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Sample records for aerodynamic lens system

  1. Computerized method and system for designing an aerodynamic focusing lens stack

    DOEpatents

    Gard, Eric; Riot, Vincent; Coffee, Keith; Woods, Bruce; Tobias, Herbert; Birch, Jim; Weisgraber, Todd

    2011-11-22

    A computerized method and system for designing an aerodynamic focusing lens stack, using input from a designer related to, for example, particle size range to be considered, characteristics of the gas to be flowed through the system, the upstream temperature and pressure at the top of a first focusing lens, the flow rate through the aerodynamic focusing lens stack equivalent at atmosphere pressure; and a Stokes number range. Based on the design parameters, the method and system determines the total number of focusing lenses and their respective orifice diameters required to focus the particle size range to be considered, by first calculating for the orifice diameter of the first focusing lens in the Stokes formula, and then using that value to determine, in iterative fashion, intermediate flow values which are themselves used to determine the orifice diameters of each succeeding focusing lens in the stack design, with the results being output to a designer. In addition, the Reynolds numbers associated with each focusing lens as well as exit nozzle size may also be determined to enhance the stack design.

  2. Implementation of an aerodynamic lens for TRIGA-SPEC

    NASA Astrophysics Data System (ADS)

    Grund, J.; Düllmann, Ch. E.; Eberhardt, K.; Nagy, Sz.; van de Laar, J. J. W.; Renisch, D.; Schneider, F.

    2016-06-01

    We report on the optimization of the gas-jet system employed to couple the TRIGA-SPEC experiment to the research reactor TRIGA Mainz. CdI2 aerosol particles suspended in N2 as carrier gas are used for an effective transport of fission products from neutron induced 235 U fission from the target chamber to a surface ion source. Operating conditions of the gas-jet were modified to enable the implementation of an aerodynamic lens, fitting into the limited space available in front of the ion source. The lens boosts the gas-jet efficiency by a factor of 4-10. The characterization of the gas-jet system as well as the design of the aerodynamic lens and efficiency studies are presented and discussed.

  3. Developing Supersonic Impactor and Aerodynamic Lens for Separation and Handling of Nano-Sized Particles

    SciTech Connect

    Goodarz Ahmadi

    2008-06-30

    A computational model for supersonic flows of compressible gases in an aerodynamic lens with several lenses and in a supersonic/hypersonic impactor was developed. Airflow conditions in the aerodynamic lens were analyzed and contour plots for variation of Mach number, velocity magnitude and pressure field in the lens were evaluated. The nano and micro-particle trajectories in the lens and their focusing and transmission efficiencies were evaluated. The computational model was then applied to design of a aerodynamic lens that could generate focus particle beams while operating under atmospheric conditions. The computational model was also applied to airflow condition in the supersonic/hypersonic impactor. Variations of airflow condition and particle trajectories in the impactor were evaluated. The simulation results could provide understanding of the performance of the supersonic and hypersonic impactors that would be helpful for the design of such systems.

  4. Collection Mode Lens System

    DOEpatents

    Fletcher, Daniel A.; Kino, Gordon S.

    2002-11-05

    A lens system including a collection lens and a microlens spaced from the collection lens adjacent the region to be observed. The diameter of the observablel region depends substantially on the radius of the microlens.

  5. Aberration design of zoom lens systems using thick lens modules.

    PubMed

    Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

    2014-12-20

    A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

  6. Evaporation of Water from Particles in the Aerodynamic Lens Inlet: An Experimental Study

    SciTech Connect

    Zelenyuk, Alla; Imre, Dan G.; Cuadra-Rodriguez, Luis A.

    2006-10-01

    The extremely high particle transmission efficiency of aerodynamic lens inlets resulted in their wide use in aerosol mass spectrometers. One of the consequences of a transport of particles from high ambient pressure into the vacuum is that it is accompanied by a rapid drop in relative humidity (RH). Since many atmospheric particles exist in the form of hygroscopic water droplets, a drop in RH may result in a significant loss of water and even a change in phase. To predict how much water will be evaporated is not feasible. Because water loss can effect in addition to particle size, its transmission efficiency, ionization probability and mass spectrum it is imperative to provide definitive experimental data that can serve to guide the field to a reasonable and uniform sampling approach. In this study we present the results of a number of carefully conducted measurements that provide the first experimentally determined benchmark of water evaporation from a range of particles, during their transport through an aerodynamic lens inlet. We conclude that the only sure way to avoid ambiguities during measurements of aerodynamic diameter in instruments that utilize low pressure aerodynamic lens inlets is to dry the particles prior to sampling.

  7. Lens system for a photo ion spectrometer

    DOEpatents

    Gruen, Dieter M.; Young, Charles E.; Pellin, Michael J.

    1990-01-01

    A lens system in a photo ion spectrometer for manipulating a primary ion beam and ionized atomic component. The atomic components are removed from a sample by a primary ion beam using the lens system, and the ions are extracted for analysis. The lens system further includes ionization resistant coatings for protecting the lens system.

  8. Lens system for a photo ion spectrometer

    DOEpatents

    Gruen, D.M.; Young, C.E.; Pellin, M.J.

    1990-11-27

    A lens system in a photo ion spectrometer for manipulating a primary ion beam and ionized atomic component is disclosed. The atomic components are removed from a sample by a primary ion beam using the lens system, and the ions are extracted for analysis. The lens system further includes ionization resistant coatings for protecting the lens system. 8 figs.

  9. System for determining aerodynamic imbalance

    NASA Technical Reports Server (NTRS)

    Churchill, Gary B. (Inventor); Cheung, Benny K. (Inventor)

    1994-01-01

    A system is provided for determining tracking error in a propeller or rotor driven aircraft by determining differences in the aerodynamic loading on the propeller or rotor blades of the aircraft. The system includes a microphone disposed relative to the blades during the rotation thereof so as to receive separate pressure pulses produced by each of the blades during the passage thereof by the microphone. A low pass filter filters the output signal produced by the microphone, the low pass filter having an upper cut-off frequency set below the frequency at which the blades pass by the microphone. A sensor produces an output signal after each complete revolution of the blades, and a recording display device displays the outputs of the low pass filter and sensor so as to enable evaluation of the relative magnitudes of the pressure pulses produced by passage of the blades by the microphone during each complete revolution of the blades.

  10. Automated Fresnel lens tester system

    SciTech Connect

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  11. Tevatron electron lens magnetic system

    SciTech Connect

    Vladimir Shiltsev et al.

    2001-07-12

    In the framework of collaboration between IHEP and FNAL, a magnetic system of the Tevatron Electron Lens (TEL) has been designed and built. The TEL is currently installed in the superconducting ring of the Tevatron proton-antiproton collider and used for experimental studies of beam-beam compensation [1].

  12. Optmization design of zoom lens systems

    NASA Astrophysics Data System (ADS)

    Li, Xiaotong; Cen, Zhaofeng

    2002-09-01

    A zoom lens system is usually composed of several components. Some of the components can be moved to change the focal length or magnification. Zoom lens system design is more complicated than fixed-focus lens design due to the moving of some components. In this paper, an optimization method that is used to design zoom lens systems is presented. Using this method, the Gaussian parameters of zoom lens systems are optimized at first, and then the initial structure parameters in each component are generated and optimized. At last the aberration balance is made using multi-configuration. In this paper the flowchart of optimization design for such complex optical systems is showed and the algorithms are described. As a conclusion, the relationship between power distribution, initial structure and the aberrations is considered at the beginning, the evaluation criteria are reliable and efficiency for designing zoom lens systems.

  13. Algorithm design of liquid lens inspection system

    NASA Astrophysics Data System (ADS)

    Hsieh, Lu-Lin; Wang, Chun-Chieh

    2008-08-01

    In mobile lens domain, the glass lens is often to be applied in high-resolution requirement situation; but the glass zoom lens needs to be collocated with movable machinery and voice-coil motor, which usually arises some space limits in minimum design. In high level molding component technology development, the appearance of liquid lens has become the focus of mobile phone and digital camera companies. The liquid lens sets with solid optical lens and driving circuit has replaced the original components. As a result, the volume requirement is decreased to merely 50% of the original design. Besides, with the high focus adjusting speed, low energy requirement, high durability, and low-cost manufacturing process, the liquid lens shows advantages in the competitive market. In the past, authors only need to inspect the scrape defect made by external force for the glass lens. As to the liquid lens, authors need to inspect the state of four different structural layers due to the different design and structure. In this paper, authors apply machine vision and digital image processing technology to administer inspections in the particular layer according to the needs of users. According to our experiment results, the algorithm proposed can automatically delete non-focus background, extract the region of interest, find out and analyze the defects efficiently in the particular layer. In the future, authors will combine the algorithm of the system with automatic-focus technology to implement the inside inspection based on the product inspective demands.

  14. Sensor Systems Collect Critical Aerodynamics Data

    NASA Technical Reports Server (NTRS)

    2010-01-01

    With the support of Small Business Innovation Research (SBIR) contracts with Dryden Flight Research Center, Tao of Systems Integration Inc. developed sensors and other components that will ultimately form a first-of-its-kind, closed-loop system for detecting, measuring, and controlling aerodynamic forces and moments in flight. The Hampton, Virginia-based company commercialized three of the four planned components, which provide sensing solutions for customers such as Boeing, General Electric, and BMW and are used for applications such as improving wind turbine operation and optimizing air flow from air conditioning systems. The completed system may one day enable flexible-wing aircraft with flight capabilities like those of birds.

  15. HSCT high lift system aerodynamic requirements

    NASA Technical Reports Server (NTRS)

    Paulson, John A.

    1992-01-01

    The viewgraphs and discussion of high lift system aerodynamic requirements are provided. Low speed aerodynamics has been identified as critical to the successful development of a High Speed Civil Transport (HSCT). The airplane must takeoff and land at a sufficient number of existing or projected airports to be economically viable. At the same time, community noise must be acceptable. Improvements in cruise drag, engine fuel consumption, and structural weight tend to decrease the wing size and thrust required of engines. Decreasing wing size increases the requirements for effective and efficient low speed characteristics. Current design concepts have already been compromised away from better cruise wings for low speed performance. Flap systems have been added to achieve better lift-to-drag ratios for climb and approach and for lower pitch attitudes for liftoff and touchdown. Research to achieve improvements in low speed aerodynamics needs to be focused on areas most likely to have the largest effect on the wing and engine sizing process. It would be desirable to provide enough lift to avoid sizing the airplane for field performance and to still meet the noise requirements. The airworthiness standards developed in 1971 will be the basis for performance requirements for an airplane that will not be critical to the airplane wing and engine size. The lift and drag levels that were required to meet the performance requirements of tentative airworthiness standards established in 1971 and that were important to community noise are identified. Research to improve the low speed aerodynamic characteristics of the HSCT needs to be focused in the areas of performance deficiency and where noise can be reduced. Otherwise, the wing planform, engine cycle, or other parameters for a superior cruising airplane would have to be changed.

  16. In-situ characterization of nanoparticle beams focused with an aerodynamic lens by Laser-Induced Breakdown Detection.

    PubMed

    Barreda, F-A; Nicolas, C; Sirven, J-B; Ouf, F-X; Lacour, J-L; Robert, E; Benkoula, S; Yon, J; Miron, C; Sublemontier, O

    2015-01-01

    The Laser-Induced Breakdown Detection technique (LIBD) was adapted to achieve fast in-situ characterization of nanoparticle beams focused under vacuum by an aerodynamic lens. The method employs a tightly focused, 21 μm, scanning laser microprobe which generates a local plasma induced by the laser interaction with a single particle. A counting mode optical detection allows the achievement of 2D mappings of the nanoparticle beams with a reduced analysis time thanks to the use of a high repetition rate infrared pulsed laser. As an example, the results obtained with Tryptophan nanoparticles are presented and the advantages of this method over existing ones are discussed. PMID:26498694

  17. In-situ characterization of nanoparticle beams focused with an aerodynamic lens by Laser-Induced Breakdown Detection

    PubMed Central

    Barreda, F.-A.; Nicolas, C.; Sirven, J.-B.; Ouf, F.-X.; Lacour, J.-L.; Robert, E.; Benkoula, S.; Yon, J.; Miron, C.; Sublemontier, O.

    2015-01-01

    The Laser-Induced Breakdown Detection technique (LIBD) was adapted to achieve fast in-situ characterization of nanoparticle beams focused under vacuum by an aerodynamic lens. The method employs a tightly focused, 21 μm, scanning laser microprobe which generates a local plasma induced by the laser interaction with a single particle. A counting mode optical detection allows the achievement of 2D mappings of the nanoparticle beams with a reduced analysis time thanks to the use of a high repetition rate infrared pulsed laser. As an example, the results obtained with Tryptophan nanoparticles are presented and the advantages of this method over existing ones are discussed. PMID:26498694

  18. In-situ characterization of nanoparticle beams focused with an aerodynamic lens by Laser-Induced Breakdown Detection.

    PubMed

    Barreda, F-A; Nicolas, C; Sirven, J-B; Ouf, F-X; Lacour, J-L; Robert, E; Benkoula, S; Yon, J; Miron, C; Sublemontier, O

    2015-10-26

    The Laser-Induced Breakdown Detection technique (LIBD) was adapted to achieve fast in-situ characterization of nanoparticle beams focused under vacuum by an aerodynamic lens. The method employs a tightly focused, 21 μm, scanning laser microprobe which generates a local plasma induced by the laser interaction with a single particle. A counting mode optical detection allows the achievement of 2D mappings of the nanoparticle beams with a reduced analysis time thanks to the use of a high repetition rate infrared pulsed laser. As an example, the results obtained with Tryptophan nanoparticles are presented and the advantages of this method over existing ones are discussed.

  19. System Identification of a Vortex Lattice Aerodynamic Model

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Kholodar, Denis; Dowell, Earl H.

    2001-01-01

    The state-space presentation of an aerodynamic vortex model is considered from a classical and system identification perspective. Using an aerodynamic vortex model as a numerical simulator of a wing tunnel experiment, both full state and limited state data or measurements are considered. Two possible approaches for system identification are presented and modal controllability and observability are also considered. The theory then is applied to the system identification of a flow over an aerodynamic delta wing and typical results are presented.

  20. 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.

  1. Zoom optical system using tunable polymer lens

    NASA Astrophysics Data System (ADS)

    Liang, Dan; Wang, Xuan Yin

    2016-07-01

    This paper demonstrated a zoom optical system with variable magnification based on the tunable polymer lens. The designed system mainly consists of two polymer lenses, voice coil motors, a doublet lens and CMOS chip. The zoom magnification can be adjusted by altering the focal length of the two elastic polymer lenses synergistically through controlling the output displacement of the voice coil motor. A static doublet lens in combination with the polymer lenses stabilize the image plane at the CMOS chip. The optical structure of the zoom system is presented, as well as a detailed description including the lens materials and fabrication process. Images with each zoom magnification are captured, and the Spot diagram and MTF are simulated using Zemax software. A change in magnification from 0.13×to 8.44×is demonstrated within the tiny 0.4 mm variation of the displacement load, and produce a 16.1×full range of magnification experimentally. Simulation analyses show that all the radii of the spot diagram under different magnifications are less than 11.3 um, and the modulation transfer function reaches 107 line pairs per mm. The designed optical system shows the potential for developing stable, integrated, and low-cost zoom systems with large magnification range.

  2. Aerodynamic preliminary analysis system 2. Part 1: Theory

    NASA Technical Reports Server (NTRS)

    Bonner, E.; Clever, W.; Dunn, K.

    1981-01-01

    A subsonic/supersonic/hypersonic aerodynamic analysis was developed by integrating the Aerodynamic Preliminary Analysis System (APAS), and the inviscid force calculation modules of the Hypersonic Arbitrary Body Program. APAS analysis was extended for nonlinear vortex forces using a generalization of the Polhamus analogy. The interactive system provides appropriate aerodynamic models for a single input geometry data base and has a run/output format similar to a wind tunnel test program. The user's manual was organized to cover the principle system activities of a typical application, geometric input/editing, aerodynamic evaluation, and post analysis review/display. Sample sessions are included to illustrate the specific task involved and are followed by a comprehensive command/subcommand dictionary used to operate the system.

  3. 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.

  4. Fabrication of a fluidic membrane lens system

    NASA Astrophysics Data System (ADS)

    Draheim, J.; Schneider, F.; Kamberger, R.; Mueller, C.; Wallrabe, U.

    2009-09-01

    We present the fabrication process of a fluidic membrane lens system with an integrated piezoelectric pumping actuator. The optical unit and the pumping unit are fabricated through casting using a hot embossing machine. Two different systems, one with a homogeneous membrane thickness, and one with an inhomogeneous membrane thickness distribution, are manufactured. The influence of the volume shrinkage of the silicone during curing on the membrane shape and on the focal length is analyzed. The assembled system achieves a focal length between +52.4 mm and -70.9 mm at a piezovoltage of ±40 V. The full-scale response time of the system is below 24 ms.

  5. Space Launch System Ascent Static Aerodynamic Database Development

    NASA Technical Reports Server (NTRS)

    Pinier, Jeremy T.; Bennett, David W.; Blevins, John A.; Erickson, Gary E.; Favaregh, Noah M.; Houlden, Heather P.; Tomek, William G.

    2014-01-01

    This paper describes the wind tunnel testing work and data analysis required to characterize the static aerodynamic environment of NASA's Space Launch System (SLS) ascent portion of flight. Scaled models of the SLS have been tested in transonic and supersonic wind tunnels to gather the high fidelity data that is used to build aerodynamic databases. A detailed description of the wind tunnel test that was conducted to produce the latest version of the database is presented, and a representative set of aerodynamic data is shown. The wind tunnel data quality remains very high, however some concerns with wall interference effects through transonic Mach numbers are also discussed. Post-processing and analysis of the wind tunnel dataset are crucial for the development of a formal ascent aerodynamics database.

  6. System Identification and POD Method Applied to Unsteady Aerodynamics

    NASA Technical Reports Server (NTRS)

    Tang, Deman; Kholodar, Denis; Juang, Jer-Nan; Dowell, Earl H.

    2001-01-01

    The representation of unsteady aerodynamic flow fields in terms of global aerodynamic modes has proven to be a useful method for reducing the size of the aerodynamic model over those representations that use local variables at discrete grid points in the flow field. Eigenmodes and Proper Orthogonal Decomposition (POD) modes have been used for this purpose with good effect. This suggests that system identification models may also be used to represent the aerodynamic flow field. Implicit in the use of a systems identification technique is the notion that a relative small state space model can be useful in describing a dynamical system. The POD model is first used to show that indeed a reduced order model can be obtained from a much larger numerical aerodynamical model (the vortex lattice method is used for illustrative purposes) and the results from the POD and the system identification methods are then compared. For the example considered, the two methods are shown to give comparable results in terms of accuracy and reduced model size. The advantages and limitations of each approach are briefly discussed. Both appear promising and complementary in their characteristics.

  7. 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.

  8. Aerodynamic preliminary analysis system 2. Part 1: Theory

    NASA Technical Reports Server (NTRS)

    Bonner, E.; Clever, W.; Dunn, K.

    1991-01-01

    An aerodynamic analysis system based on potential theory at subsonic and/or supersonic speeds and impact type finite element solutions at hypersonic conditions is described. Three dimensional configurations having multiple nonplanar surfaces of arbitrary planform and bodies of noncircular contour may be analyzed. Static, rotary, and control longitudinal and lateral directional characteristics may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. The program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

  9. Aerodynamic preliminary analysis system 2. Part 2: User's manuals

    NASA Technical Reports Server (NTRS)

    Divan, P.

    1981-01-01

    An aerodynamic analysis system based on potential theory at subsonic/supersonic speeds and impact type finite element solutions at hypersonic conditions is described. Three dimensional configurations having multiple nonplanar surfaces of arbitrary planform and bodies of noncircular contour may be analyzed. Static, rotary, and control longitudinal and lateral directional chracteristics may be generated. The analysis has been implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Typical simulation indicates that program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

  10. The analysis of optical wave beams propagation in lens systems

    NASA Astrophysics Data System (ADS)

    Kazakov, I.; Mosentsov, S.; Moskaletz, O.

    2016-08-01

    In this paper some aspects of the formation and propagation of optical wave beams in lens systems were considered. As an example, the two-lens optical information processing system was considered. Analysis of the two-lens optical circuit has been made with a systems approach perspective. As part of the radio-optical analogies had been applied certain provisions of the theory of dynamical systems to the spatial optical system. The lens system is represented as a simple series-connected optical elements with known spatial impulse response. General impulse response of such a system has been received, as well as consider some special cases of the impulse response. The question of the relationship between the parameters and the size of the input aperture lenses for undistorted transmission of the optical signal has been considered. Analysis of the energy loss resulting from the finite aperture of the lens. It's based on an assessment of the fraction of radiation that propagates beyond the lens. Analysis showed that the energy losses depend explicitly on the following parameters: radiation wavelength, distance between input aperture and lens, and ratio of the input aperture and lens aperture. With the computer help simulation the dependence of losses was shown on the above parameters

  11. An electrostatically and a magnetically confined electron gun lens system

    NASA Technical Reports Server (NTRS)

    Bernius, Mark T.; Man, Kin F.; Chutjian, Ara

    1988-01-01

    Focal properties, electron trajectory calculations, and geometries are given for two electron 'gun' lens systems that have a variety of applications in, for example, electron-neutral and electron-ion scattering experiments. One nine-lens system utilizes only electrostatic confinement and is capable of focusing electrons onto a fixed target with extremely small divergence angles, over a range of final energies 1-790 eV. The second gun lens system is a simpler three-lens system suitable for use in a uniform, solenoidal magnetic field. While the focusing properties of such a magnetically confined lens systenm are simpler to deal with, the system does illustrate features of electron extraction and Brillouin flow that have not been suitably emphasized in the literature.

  12. Oxygen transfer in the corneal-contact lens system.

    PubMed

    Garr-Peters, J M; Ho, C S

    1987-01-01

    The clinical results of contact lens wearers indicate that materials which theoretically are adequate to prevent corneal hypoxia and edema do not perform optimally under actual wearing conditions. Optimization of the cornea-tear-lens system requires an analysis of the modes of oxygen transport, mass transfer resistances, and characteristic dimensions. The lens properties are a function of polymer composition. Thus, investigations for ideal lens materials may result in limitless test copolymers and graft polymers of siloxane, methylmethacrylate, 2-hydroxyethyl-methacrylate, vinylpyrollidone, vinylacetate, and cellulose acetate butyrate of varying degrees of cross-linking and crystallinity. In an attempt to channel research efforts, this review will state the developments to date and the desirable properties of an optimal cornea-tear-lens system. The logic should encompass a theory and model whereby parameters are identified and varied within satisfactory physiological limitations, and experiments which provide data indicative of the in vivo conditions. The parameters must reflect the inherent transport properties of the corneal-contact lens system. Contact lenses may be categorized as soft, gas-permeable rigid/hydrophobic flexible, or hard. The major differences between these three categories are the properties: equilibrium water content or degree of hydration, tendency for water pervaporation and/or dehydration, surface hydrophobicity, thermal conductivity, oxygen diffusivity and solubility, lens thickness, rest height over corneal tear, flexibility, lens mobility over the cornea, cross-linking, crystallinity, stagnant boundary layer resistances, and manufacturing processes. Aside from complications presented by lens coatings and cleansing solutions, the most common problems experienced by lens wearers include corneal edema, dehydration involving the lens and the cornea, "blurry" vision due to localized corneal anoxia, debris trapped under the lens, and deposits on

  13. Note: A combined aerodynamic lens/ambient pressure x-ray photoelectron spectroscopy experiment for the on-stream investigation of aerosol surfaces

    SciTech Connect

    Mysak, Erin R.; Starr, David E.; Wilson, Kevin R.; Bluhm, Hendrik

    2010-01-15

    We discuss a new approach for the measurement of the surfaces of free aerosol particles with diameters from 50 to 1000 nm. Particles in this size range have significant influence on the heterogeneous chemistry in the atmosphere and affect human health. Interfacing an aerodynamic lens to an ambient pressure x-ray photoelectron spectrometer permits measurement of the surface chemical composition of unsupported aerosol particles in real time. We discuss the basic considerations for the design of such an instrument, its current limitations and potentials for improvement. Results from a proof-of-principle experiment on silicon oxide particles with average diameters of 270 nm are shown.

  14. Studies of gravitational lens systems discovered in the Cosmic Lens All-Sky Survey

    NASA Astrophysics Data System (ADS)

    Rusin, David Joseph

    2001-11-01

    This thesis describes research conducted on and inspired by the Cosmic Lens All-Sky Survey (CLASS), which searches for new cases of gravitational lensing among compact radio sources. CLASS aims to provide the largest and best-studied sample of lens systems for use in constraining the properties of galaxy mass distributions, determining the Hubble parameter and placing limits on the cosmological constant. The goal of this thesis was to complete observations of the CLASS sample, discover and thoroughly investigate new lenses, and apply them to interesting astrophysical problems. We begin with a detailed overview of the CLASS project, including scientific goals, the radio source sample, survey observations, candidate selection and follow-ups. Results are then presented from the third phase of the CLASS survey (CLASS-3), which yielded three new gravitational lens systems. 130850+054 and 131152+199 both consist of a pair of lensed images. 131359+154 features six images of a single source, and is the first arcsecond-scale system in which a source is lensed into more than four images. We also present observations and modeling of the CLASS-2 gravitational lens B2319+051. We use the absence of detectable central images in deep radio maps of CLASS lens systems to place powerful constraints on the inner mass profiles of leasing galaxies. These analyses imply that the profile slopes cannot be much shallower than isothermal. Finally, we consider the relative frequency of two and four-image lens systems, and demonstrate that there is a statistically significant overdensity of quads in the CLASS sample. We investigate a range of factors that may be increasing the frequency of radio quads, including external shear fields, mass distributions flatter than the light, shallow leasing mass profiles, finite core radii, satellite galaxies, and alterations to the luminosity function for faint flat-spectrum radio sources. Surprisingly, none of these mechanisms provide a particularly

  15. High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients

    PubMed Central

    Sengor, Tomris; Kurna, Sevda Aydin; Aki, Suat; Özkurt, Yelda

    2011-01-01

    Background: The aim of the study was to examine the clinical success of high Dk (oxygen permeability) piggyback contact lens (PBCL) systems for the correction of contact lens intolerant keratoconus patients. Methods: Sixteen patients (29 eyes) who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen transmissibility or Dk/t = 150 units) and fluorosilicone methacrylate copolymer (Dk/t = 100 units) lenses were chosen as the PBCL systems. The clinical examinations included visual acuity and corneal observation by biomicroscopy, keratometer reading, and fluorescein staining before and after fitting the PBCL system. Results: Indications for using PBCL system were: lens stabilization and comfort, improving comfort, and adding protection to the cone. Visual acuities increased significantly in all of the patients compared with spectacles (P = 0). Improvement in visual acuity compared with rigid lenses alone was recorded in 89.7% of eyes and no alteration of the visual acuity was observed in 10.3% of the eyes. Wearing time of PBCL systems for most of the patients was limited time (mean 6 months, range 3–12 months); thereafter they tolerated rigid lenses alone except for 2 patients. Conclusion: The PBCL system is a safe and effective method to provide centering and corneal protection against mechanical trauma by the rigid lenses for keratoconus patients and may increase contact lens tolerance. PMID:21468342

  16. Aerodynamic-structural analysis of dual bladed helicopter systems

    NASA Technical Reports Server (NTRS)

    Selberg, B. P.; Cronin, D. L.; Rokhsaz, K.; Dykman, J. R.; Yager, C. J.

    1980-01-01

    The aerodynamic and structural feasibility of the birotor blade concept is assessed. The inviscid flow field about the dual bladed rotor was investigated to determine the aerodynamic characteristics for various dual rotor blade placement combinations with respect to blade stagger, gap, and angle of attack between the two blades. The boundary layer separation on the rotors was studied and three dimensional induced drag calculations for the dual rotor system are presented. The thrust and power requirements of the rotor system were predicted. NASTRAN, employed as the primary modeling tool, was used to obtain a model for predicting in plane bending, out of plane bending, and the torsional behavior of the birotors. Local hub loads, blade loads, and the natural frequencies for the birotor configuration are discussed.

  17. Parameter identification for nonlinear aerodynamic systems

    NASA Technical Reports Server (NTRS)

    Pearson, Allan E.

    1991-01-01

    Work continues on frequency analysis for transfer function identification, both with respect to the continued development of the underlying algorithms and in the identification study of two physical systems. Some new results of a theoretical nature were recently obtained that lend further insight into the frequency domain interpretation of the research. Progress in each of those areas is summarized. Although not related to the system identification problem, some new results were obtained on the feedback stabilization of linear time lag systems.

  18. Aerodynamic preliminary analysis system. Part 1: Theory. [linearized potential theory

    NASA Technical Reports Server (NTRS)

    Bonner, E.; Clever, W.; Dunn, K.

    1978-01-01

    A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple non-planar surfaces of arbitrary planform and open or closed slender bodies of non-circular contour may be analyzed. Longitudinal and lateral-directional static and rotary derivative solutions may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

  19. Lens-coupled x-ray imaging systems

    NASA Astrophysics Data System (ADS)

    Fan, Helen Xiang

    Digital radiography systems are important diagnostic tools for modern medicine. The images are produced when x-ray sensitive materials are coupled directly onto the sensing element of the detector panels. As a result, the size of the detector panels is the same size as the x-ray image. An alternative to the modern DR system is to image the x-ray phosphor screen with a lens onto a digital camera. Potential advantages of this approach include rapid readout, flexible magnification and field of view depending on applications. We have evaluated lens-coupled DR systems for the task of signal detection by analyzing the covariance matrix of the images for three cases, using a perfect detector and lens, when images are affected by blurring due to the lens and screen, and for a signal embedded in a complex random background. We compared the performance of lens-coupled DR systems using three types of digital cameras. These include a scientific CCD, a scientific CMOS, and a prosumer DSLR camera. We found that both the prosumer DSLR and the scientific CMOS have lower noise than the scientific CCD camera by looking at their noise power spectrum. We have built two portable low-cost DR systems, which were used in the field in Nepal and Utah. We have also constructed a lens-coupled CT system, which included a calibration routine and an iterative reconstruction algorithm written in CUDA.

  20. Adaptive neuro-fuzzy estimation of optimal lens system parameters

    NASA Astrophysics Data System (ADS)

    Petković, Dalibor; Pavlović, Nenad T.; Shamshirband, Shahaboddin; Mat Kiah, Miss Laiha; Badrul Anuar, Nor; Idna Idris, Mohd Yamani

    2014-04-01

    Due to the popularization of digital technology, the demand for high-quality digital products has become critical. The quantitative assessment of image quality is an important consideration in any type of imaging system. Therefore, developing a design that combines the requirements of good image quality is desirable. Lens system design represents a crucial factor for good image quality. Optimization procedure is the main part of the lens system design methodology. Lens system optimization is a complex non-linear optimization task, often with intricate physical constraints, for which there is no analytical solutions. Therefore lens system design provides ideal problems for intelligent optimization algorithms. There are many tools which can be used to measure optical performance. One very useful tool is the spot diagram. The spot diagram gives an indication of the image of a point object. In this paper, one optimization criterion for lens system, the spot size radius, is considered. This paper presents new lens optimization methods based on adaptive neuro-fuzzy inference strategy (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated.

  1. Light Vehicle-Trailer Systems' Aerodynamics Testing and Simulation

    NASA Astrophysics Data System (ADS)

    Boyer, Henry; Sigurdson, Lorenz; Lange, Carlos

    2014-11-01

    A wide range of trailers with very poor aerodynamics are hauled long distances across a vast North American highway system. Our goal was to use preliminary smoke-wire flow visualizations to learn: the characteristic flow patterns over models representing modern Vehicle-Trailer Systems (VTS); what improvements need to be made in the experimental set-up; and if there is an opportunity for reduction in aerodynamic drag. Visualization tests were done in an open circuit wind tunnel, with a cross-sectional area of 0.3 m2. Detailed models of light duty trucks and trailers were used at a Reynolds number of 13,700. Images of the streaklines indicated two characteristic features. One was the presence of a stagnation point on the leading face of the trailer followed by a separation bubble on its top. The other feature was an unexpected separation bubble on the hood of the towing vehicle. We determined that it did not have a significant effect on the downstream flow pattern. By adding a small wedge deflector on the cab of the vehicle it was concluded that there is an opportunity for significant improvement of the VTS aerodynamics. Computational simulation of the flow is underway. Support from the Natural Sciences and Engineering Research Council of Canada Discovery Grant Number 41747 is gratefully acknowledged.

  2. Aerodynamic Flow Field Measurements for Automotive Systems

    NASA Technical Reports Server (NTRS)

    Hepner, Timothy E.

    1999-01-01

    The design of a modern automotive air handling system is a complex task. The system is required to bring the interior of the vehicle to a comfortable level in as short a time as possible. A goal of the automotive industry is to predict the interior climate of an automobile using advanced computational fluid dynamic (CFD) methods. The development of these advanced prediction tools will enable better selection of engine and accessory components. The goal of this investigation was to predict methods used by the automotive industry. To accomplish this task three separate experiments were performed. The first was a laboratory setup where laser velocimeter (LV) flow field measurements were made in the heating and air conditioning unit of a Ford Windstar. The second involved flow field measurements in the engine compartment of a Ford Explorer, with the engine running idle. The third mapped the flow field exiting the center dashboard panel vent inside the Explorer, while the circulating fan operated at 14 volts. All three experiments utilized full-coincidence three-component LV systems. This enabled the mean and fluctuating velocities to be measured along with the Reynolds stress terms.

  3. EHF dielectric lens antenna for Satellite Communication Systems

    NASA Astrophysics Data System (ADS)

    Rotman, W.

    1983-01-01

    Dielectric lens antennas are applicable to the design of multiple-beam antenna (MBA) systems on EHF communication satellites. Advantages include excellent wide angle scanning properties and elimination of feed blockage. This report describes an experimental 90 lambda dia. zoned dielectric lens, operating at 44 GHz, which was fabricated and tested in order to estimate the performance of a dielectric lens MBA. Measurements showed that the lens generated a beam with a half-power beamwidth (HPBW) of 0.7 deg which could be steered over a total scan angle of 18 deg (corresponding to the Earth's field-of-view from a geosynchronous satellite) with a scanning loss of less than 1 dB and a gain in excess of 47 dBi measured at the sub-satellite point over a 5% bandwidth. A theoretical analysis of the radiation characteristics of the lens antenna, using ray tracing and geometric optics techniques, gave excellent agreement with the measurements. Simplified design equations were developed to facilitate evaluation and development of lens antenna systems of this type.

  4. Improved illumination system of laparoscopes using an aspherical lens array

    PubMed Central

    Wu, Rengmao; Qin, Yi; Hua, Hong

    2016-01-01

    The current fiber-based illumination systems of laparoscopes are unable to uniformly illuminate a large enough area in abdomen due to the limited numerical aperture (NA) of the fiber bundle. Most energy is concentrated in a small region at the center of the illumination area. This limitation becomes problematic in laparoscopes which require capturing a wide field of view. In this paper, we propose an aspherical lens array which is used to direct the outgoing rays from the fiber bundle of laparoscope to produce a more uniformly illuminated, substantially larger field coverage than standalone fiber source. An intensity feedback method is developed to design the aspherical lens unit for extended non-Lambertian sources, which is the key to the design of this lens array. By this method, the lens unit is obtained after only one iteration, and the lens array is constructed by Boolean operation. Then, the ray-tracing technique is used to verify the design. Further, the lens array is fabricated and experimental tests are performed. The results clearly show that the well-illuminated area is increased to about 0.107m2 from 0.02m2 (about 5x larger than a standard fiber illumination source). More details of the internal organs can be clearly observed under this improved illumination condition, which also reflects the significant improvement in the optical performance of the laparoscope. PMID:27375940

  5. Improved illumination system of laparoscopes using an aspherical lens array.

    PubMed

    Wu, Rengmao; Qin, Yi; Hua, Hong

    2016-06-01

    The current fiber-based illumination systems of laparoscopes are unable to uniformly illuminate a large enough area in abdomen due to the limited numerical aperture (NA) of the fiber bundle. Most energy is concentrated in a small region at the center of the illumination area. This limitation becomes problematic in laparoscopes which require capturing a wide field of view. In this paper, we propose an aspherical lens array which is used to direct the outgoing rays from the fiber bundle of laparoscope to produce a more uniformly illuminated, substantially larger field coverage than standalone fiber source. An intensity feedback method is developed to design the aspherical lens unit for extended non-Lambertian sources, which is the key to the design of this lens array. By this method, the lens unit is obtained after only one iteration, and the lens array is constructed by Boolean operation. Then, the ray-tracing technique is used to verify the design. Further, the lens array is fabricated and experimental tests are performed. The results clearly show that the well-illuminated area is increased to about 0.107m(2) from 0.02m(2) (about 5x larger than a standard fiber illumination source). More details of the internal organs can be clearly observed under this improved illumination condition, which also reflects the significant improvement in the optical performance of the laparoscope. PMID:27375940

  6. One dimensional wavefront distortion sensor comprising a lens array system

    DOEpatents

    Neal, D.R.; Michie, R.B.

    1996-02-20

    A 1-dimensional sensor for measuring wavefront distortion of a light beam as a function of time and spatial position includes a lens system which incorporates a linear array of lenses, and a detector system which incorporates a linear array of light detectors positioned from the lens system so that light passing through any of the lenses is focused on at least one of the light detectors. The 1-dimensional sensor determines the slope of the wavefront by location of the detectors illuminated by the light. The 1 dimensional sensor has much greater bandwidth that 2 dimensional systems. 8 figs.

  7. One dimensional wavefront distortion sensor comprising a lens array system

    DOEpatents

    Neal, Daniel R.; Michie, Robert B.

    1996-01-01

    A 1-dimensional sensor for measuring wavefront distortion of a light beam as a function of time and spatial position includes a lens system which incorporates a linear array of lenses, and a detector system which incorporates a linear array of light detectors positioned from the lens system so that light passing through any of the lenses is focused on at least one of the light detectors. The 1-dimensional sensor determines the slope of the wavefront by location of the detectors illuminated by the light. The 1 dimensional sensor has much greater bandwidth that 2 dimensional systems.

  8. Aerodynamic Tests of the Space Launch System for Database Development

    NASA Technical Reports Server (NTRS)

    Pritchett, Victor E.; Mayle, Melody N.; Blevins, John A.; Crosby, William A.; Purinton, David C.

    2014-01-01

    The Aerosciences Branch (EV33) at the George C. Marshall Space Flight Center (MSFC) has been responsible for a series of wind tunnel tests on the National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) vehicles. The primary purpose of these tests was to obtain aerodynamic data during the ascent phase and establish databases that can be used by the Guidance, Navigation, and Mission Analysis Branch (EV42) for trajectory simulations. The paper describes the test particulars regarding models and measurements and the facilities used, as well as database preparations.

  9. Aerodynamic thermal simulation system. Part 1: Radiant array (instruction manual)

    NASA Technical Reports Server (NTRS)

    Kitchar, A. F.; Steuffen, R. L.

    1973-01-01

    An aerodynamic thermal simulation system (ATSS) is presented. The construction of the system, the maintenance, set up, and operations are reported. System description of the radiant array is given along with the array subsystems modular heating unit, adjustable stanchion frame, cooling water system, and the gaseous nitrogen cooling system. The array configuration procedure outlines the set up and the start up. Maintenance procedures involve both lamp maintenance and reflector maintenance along with weather protection. Drawing codes are included. Descriptions of the 36 zone ATSS controls are also given. Each zone is an independent closed loop temperature control circuit. Procedures are presented for starting and stopping the system. The DATA-TRAK programmer and its operation, instruction manuals for the temperature controller and the power regulator and discriptions of peripheral equipment are discussed.

  10. A smoke generator system for aerodynamic flight research

    NASA Technical Reports Server (NTRS)

    Richwine, David M.; Curry, Robert E.; Tracy, Gene V.

    1989-01-01

    A smoke generator system was developed for in-flight vortex flow studies on the F-18 high alpha research vehicle (HARV). The development process included conceptual design, a survey of existing systems, component testing, detailed design, fabrication, and functional flight testing. Housed in the forebody of the aircraft, the final system consists of multiple pyrotechnic smoke cartridges which can be fired simultaneously or in sequence. The smoke produced is ducted to desired locations on the aircraft surface. The smoke generator system (SGS) has been used successfully to identify vortex core and core breakdown locations as functions of flight condition. Although developed for a specific vehicle, this concept may be useful for other aerodynamic flight research which requires the visualization of local flows.

  11. A laser velocimeter system for large-scale aerodynamic testing

    NASA Technical Reports Server (NTRS)

    Reinath, M. S.; Orloff, K. L.; Snyder, P. K.

    1984-01-01

    A unique laser velocimeter was developed that is capable of sensing two orthogonal velocity components from a variable remote distance of 2.6 to 10 m for use in the 40- by 80-Foot and 80- by 120-Foot Wind Tunnels and the Outdoor Aerodynamic Research Facility at Ames Research Center. The system hardware, positioning instrumentation, and data acquisition equipment are described in detail; system capabilities and limitations are discussed; and expressions for systematic and statistical accuracy are developed. Direct and coupled laboratory measurements taken with the system are compared with measurements taken with a laser velocimeter of higher spatial resolution, and sample data taken in the open circuit exhaust flow of a 1/50-scale model of the 80- by 120-Foot Wind Tunnel are presented.

  12. Innovative light collimator with afocal lens and total internal reflection lens for daylighting system.

    PubMed

    Chen, Bo-Jian; Chen, Yin-Ti; Ullah, Irfan; Chou, Chun-Han; Chan, Kai-Cyuan; Lai, Yi-Lung; Lin, Chia-Ming; Chang, Cheng-Ming; Whang, Allen Jong-Woei

    2015-10-01

    This research presents a novel design of the collimator, which uses total internal reflection (TIR), convex, and concave lenses for the natural light illumination system (NLIS). The concept of the NLIS is to illuminate building interiors with natural light, which saves energy consumption. The TIR lens is used to collimate the light, and convex and concave lenses are used to converge the light to the required area. The results have shown that the efficiency in terms of achieving collimated light using the proposed collimator at the output of the light collector is better than that of a previous system without a collimator. PMID:26479648

  13. Aerodynamic preliminary analysis system 2. Part 2: User's manual

    NASA Technical Reports Server (NTRS)

    Sova, G.; Divan, P.; Spacht, L.

    1991-01-01

    An aerodynamic analysis system based on potential theory at subsonic and/or supersonic speeds and impact type finite element solutions at hypersonic conditions is described. Three dimensional configurations have multiple nonplanar surfaces of arbitrary planforms and bodies of noncircular contour may be analyzed. Static, rotary, and control longitudinal and lateral-directional characteristics may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis. Computation times on an IBM 3081 are typically less than one minute of CPU/Mach number at subsonic, supersonic, or hypersonic speeds. This is a user manual for the computer programming.

  14. Development of a contact lens quality monitoring system

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; Shen, Chih-Ping; Sprinkle, Danny R.

    1992-01-01

    The quality of contact lens samples depends strongly on their free volume fractions. It is expected that the free volume fraction of the test samples will also impact their attenuation coefficients for soft x rays. Samples with larger free volume fractions should have lower linear attenuation coefficients. Linear attenuation coefficients for Cd-109/Ag-109 x rays have been measured in five contact lens samples. It has been shown that the difference in the linear attenuation coefficients of discs from any given sample are entirely due to the difference in their respective volume fractions. It is therefore concluded that an x ray attenuation measurement system can serve as a quality monitor for contact lens polymers.

  15. Intraocular camera for retinal prostheses: Refractive and diffractive lens systems

    NASA Astrophysics Data System (ADS)

    Hauer, Michelle Christine

    The focus of this thesis is on the design and analysis of refractive, diffractive, and hybrid refractive/diffractive lens systems for a miniaturized camera that can be surgically implanted in the crystalline lens sac and is designed to work in conjunction with current and future generation retinal prostheses. The development of such an intraocular camera (IOC) would eliminate the need for an external head-mounted or eyeglass-mounted camera. Placing the camera inside the eye would allow subjects to use their natural eye movements for foveation (attention) instead of more cumbersome head tracking, would notably aid in personal navigation and mobility, and would also be significantly more psychologically appealing from the standpoint of personal appearances. The capability for accommodation with no moving parts or feedback control is incorporated by employing camera designs that exhibit nearly infinite depth of field. Such an ultracompact optical imaging system requires a unique combination of refractive and diffractive optical elements and relaxed system constraints derived from human psychophysics. This configuration necessitates an extremely compact, short focal-length lens system with an f-number close to unity. Initially, these constraints appear highly aggressive from an optical design perspective. However, after careful analysis of the unique imaging requirements of a camera intended to work in conjunction with the relatively low pixellation levels of a retinal microstimulator array, it becomes clear that such a design is not only feasible, but could possibly be implemented with a single lens system.

  16. The Anatomy of a Quadruply Imaged Gravitational Lens System

    SciTech Connect

    Suyu, Sherry H.; Blandford, R.D.; /Caltech /KIPAC, Menlo Park

    2005-06-29

    The key to using a strong gravitational lens system to measure the Hubble constant is to obtain an accurate model of the lens potential. In this paper, we investigate the properties of gravitational lens B1608+656, a quadruply-imaged lens system with an extended source intensity distribution. Our analysis is valid for generic quadruply-lensed systems. Limit curves and isophotal separatrices are defined for such systems, and we show that the isophotal separatrices must intersect at the critical curves and the satellite isophotes must be tangent to the limit curves. The current model of B1608+656 (Koopmans et al. 2003) satisfies these criteria for some, but not all, of the isophotal separatrices within the observational uncertainty.We study a non-parametric method of potential reconstruction proposed by Blandford, Surpi & Kundic (2001) and demonstrate that although the method works in principle and elucidates image formation, the initial potential only converges to the true model when it is within {approx} 1 percent of the true model.

  17. 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.

  18. Global Optimization Methods for Gravitational Lens Systems with Regularized Sources

    NASA Astrophysics Data System (ADS)

    Rogers, Adam; Fiege, Jason D.

    2012-11-01

    Several approaches exist to model gravitational lens systems. In this study, we apply global optimization methods to find the optimal set of lens parameters using a genetic algorithm. We treat the full optimization procedure as a two-step process: an analytical description of the source plane intensity distribution is used to find an initial approximation to the optimal lens parameters; the second stage of the optimization uses a pixelated source plane with the semilinear method to determine an optimal source. Regularization is handled by means of an iterative method and the generalized cross validation (GCV) and unbiased predictive risk estimator (UPRE) functions that are commonly used in standard image deconvolution problems. This approach simultaneously estimates the optimal regularization parameter and the number of degrees of freedom in the source. Using the GCV and UPRE functions, we are able to justify an estimation of the number of source degrees of freedom found in previous work. We test our approach by applying our code to a subset of the lens systems included in the SLACS survey.

  19. Task-based evaluation of practical lens designs for lens-coupled digital mammography systems

    NASA Astrophysics Data System (ADS)

    Chen, Liying; Foo, Leslie D.; Cortesi, Rebecca L.; Thompson, Kevin P.; Barrett, Harrison H.

    2007-03-01

    Recent developments in low-noise, large-area CCD detectors have renewed interest in radiographic systems that use a lens to couple light from a scintillation screen to a detector. The lenses for this application must have very large numerical apertures and high spatial resolution over a FOV. This paper expands on our earlier work by applying the principles of task-based assessment of image quality to development of meaningful figures of merit for the lenses. The task considered in this study is detection of a lesion in a mammogram, and the figure of merit used is the lesion detectability, expressed as a task-based signal-to-noise ratio (SNR), for a channelized Hotelling observer (CHO). As in the previous work, the statistical model accounts for the random structure in the breast, the statistical properties of the scintillation screen, the random coupling of light to the CCD, the detailed structure of the shift-variant lens point spread function (PSF), and Poisson noise of the X-ray flux. The lenses considered range from F/0.9 to F/1.2. All yield nominally the same spot size at a given field. Among the F/0.9 lenses, some of them were designed by conventional means for high resolution and some for high contrast, and the shapes of the PSF differ considerably. The results show that excessively large lens numerical apertures do not improve the task-based SNR but dramatically increase the optics fabrication cost. Contrary to common wisdom, high-contrast designs have higher task-based SNRs than high-resolution designs when the signal is small. Additionally, we constructed a merit function to successfully tune the lenses to perform equally well anywhere in the FOV.

  20. Estimation of Aerodynamic Stability Derivatives for Space Launch System and Impact on Stability Margins

    NASA Technical Reports Server (NTRS)

    Pei, Jing; Wall, John

    2013-01-01

    This paper describes the techniques involved in determining the aerodynamic stability derivatives for the frequency domain analysis of the Space Launch System (SLS) vehicle. Generally for launch vehicles, determination of the derivatives is fairly straightforward since the aerodynamic data is usually linear through a moderate range of angle of attack. However, if the wind tunnel data lacks proper corrections then nonlinearities and asymmetric behavior may appear in the aerodynamic database coefficients. In this case, computing the derivatives becomes a non-trivial task. Errors in computing the nominal derivatives could lead to improper interpretation regarding the natural stability of the system and tuning of the controller parameters, which would impact both stability and performance. The aerodynamic derivatives are also provided at off nominal operating conditions used for dispersed frequency domain Monte Carlo analysis. Finally, results are shown to illustrate that the effects of aerodynamic cross axis coupling can be neglected for the SLS configuration studied

  1. Ultrathin Alvarez lens system actuated by artificial muscles.

    PubMed

    Petsch, S; Grewe, A; Köbele, L; Sinzinger, S; Zappe, H

    2016-04-01

    A key feature of Alvarez lenses is that they may be tuned in focal length using lateral rather than axial translation, thus reducing the overall length of a focus-tunable optical system. Nevertheless the bulk of classical microsystems actuators limits further miniaturization. We present here a new, ultrathin focus-tunable Alvarez lens fabricated using molding techniques and actuated using liquid crystal elastomer (LCE) artificial muscle actuators. The large deformation generated by the LCE actuators permits the integration of the actuators in-plane with the mechanical and optical system and thus reduces the device thickness to only 1.6 mm. Movement of the Alvarez lens pair of 178 μm results in a focal length change of 3.3 mm, based on an initial focal length of 28.4 mm. This design is of considerable interest for realization of ultraflat focus-tunable and zoom systems. PMID:27139677

  2. Effects of aerodynamic lift on the stability of tethered subsatellite system

    NASA Astrophysics Data System (ADS)

    Keshmiri, Mehdi; Misra, Arun K.

    Dynamics and stability of a two-body tethered system are investigated considering the aerodynamic lift on the subsatellite in addition to he aerodynamic drag. The Free Molecular Flow Model is used to calculate the aerodynamic forces on the subsatellite. Equilibrium configurations of the system are obtained numerically. Equations of motion are linearized analytically about the equilibrium configuration through a symbolic manipulation language, Maple V., and stability behavior of small oscillations about the equilibrium configuration is analyzed. An extensive parametric study is done to understand the effect of aerodynamic forces (lift and drag) on the stability of the uncontrolled system. It is shown that the stability behavior changes significantly if the subsatellite is changed from a body with no lift to a body with lift. Hence, an unstable system with a spherical subsatellite can be stabilized if aerodynamic surfaces are appropriately added. It is concluded that consideration of the aerodynamic lifting forces in addition to the aerodynamic drag forces on the subsatellite is indispensible for proper design of a tethered subsatellite system deployed in a low-altitude orbit.

  3. Flexible Thermal Protection System Development for Hypersonic Inflatable Aerodynamic Decelerators

    NASA Technical Reports Server (NTRS)

    DelCorso, Joseph A.; Bruce, Walter E., III; Hughes, Stephen J.; Dec, John A.; Rezin, Marc D.; Meador, Mary Ann B.; Guo, Haiquan; Fletcher, Douglas G.; Calomino, Anthony M.; Cheatwood, McNeil

    2012-01-01

    The Hypersonic Inflatable Aerodynamic Decelerators (HIAD) project has invested in development of multiple thermal protection system (TPS) candidates to be used in inflatable, high downmass, technology flight projects. Flexible TPS is one element of the HIAD project which is tasked with the research and development of the technology ranging from direct ground tests, modelling and simulation, characterization of TPS systems, manufacturing and handling, and standards and policy definition. The intent of flexible TPS is to enable large deployable aeroshell technologies, which increase the drag performance while significantly reducing the ballistic coefficient of high-mass entry vehicles. A HIAD requires a flexible TPS capable of surviving aerothermal loads, and durable enough to survive the rigors of construction, handling, high density packing, long duration exposure to extrinsic, in-situ environments, and deployment. This paper provides a comprehensive overview of key work being performed within the Flexible TPS element of the HIAD project. Included in this paper is an overview of, and results from, each Flexible TPS research and development activity, which includes ground testing, physics-based thermal modelling, age testing, margins policy, catalysis, materials characterization, and recent developments with new TPS materials.

  4. Creative optomechanical tolerancing in lens systems

    NASA Astrophysics Data System (ADS)

    Lee, Kim H.; Yoon, Youngshik; Maxwell, Jonathan

    1998-09-01

    The interface between optical design and fine-mechanical design is a creatively fertile stage in the design of an optical system. The optical designer learns `What the system is all about' and the fine-mechanical engineer is liberated creatively by finding out what the priorities are. On the other hand, optical tolerancing as a discipline, which is an attractive mix of optical physics at one end and hard-nosed mechanical pragmatism at the other, has a relatively fragmented literature. It is the purpose of this paper to (1) Point out some cultural contrasts between optical engineers, mechanical engineers and physicists in this context, (2) To present a new method of displaying the optical surface sensitivities so that one may identify datum surfaces in an intuitive way and (3) To summarize some useful formulae which provide a key to the mounting of optical components. Together these three aspects illustrate the scenery of this fertile terrain.

  5. Integrated Computational System for Aerodynamic Steering and Visualization

    NASA Technical Reports Server (NTRS)

    Hesselink, Lambertus

    1999-01-01

    In February of 1994, an effort from the Fluid Dynamics and Information Sciences Divisions at NASA Ames Research Center with McDonnel Douglas Aerospace Company and Stanford University was initiated to develop, demonstrate, validate and disseminate automated software for numerical aerodynamic simulation. The goal of the initiative was to develop a tri-discipline approach encompassing CFD, Intelligent Systems, and Automated Flow Feature Recognition to improve the utility of CFD in the design cycle. This approach would then be represented through an intelligent computational system which could accept an engineer's definition of a problem and construct an optimal and reliable CFD solution. Stanford University's role focused on developing technologies that advance visualization capabilities for analysis of CFD data, extract specific flow features useful for the design process, and compare CFD data with experimental data. During the years 1995-1997, Stanford University focused on developing techniques in the area of tensor visualization and flow feature extraction. Software libraries were created enabling feature extraction and exploration of tensor fields. As a proof of concept, a prototype system called the Integrated Computational System (ICS) was developed to demonstrate CFD design cycle. The current research effort focuses on finding a quantitative comparison of general vector fields based on topological features. Since the method relies on topological information, grid matching and vector alignment is not needed in the comparison. This is often a problem with many data comparison techniques. In addition, since only topology based information is stored and compared for each field, there is a significant compression of information that enables large databases to be quickly searched. This report will (1) briefly review the technologies developed during 1995-1997 (2) describe current technologies in the area of comparison techniques, (4) describe the theory of our new

  6. Achromatic lens systems for near infrared instruments.

    NASA Astrophysics Data System (ADS)

    Oliva, E.; Gennari, S.

    1995-11-01

    The chromatic characteristics of glasses transmitting in the near infrared (λ<=2.5μm) are analyzed. Achromatic systems with superb characteristics can be obtained by coupling the crystals BaF_2_, SrF_2_ and CaF_2_ with the IR Schott glasses irg2, irg3 and irg7, respectively. The best performances are obtained using BaF_2_-irg2 and SrF_2_- irg3 while CaF_2_-irg7 is worse (due to the lower Abbe number of CaF_2_) but significantly better than other pairs normally used in IR astronomical instrumentation. Use of these combinations could much simplify the design of astronomical focal plane instruments. Measurements of the refraction index of the IR glasses at cryogenic temperatures are however necessary. As a practical application we present the preliminary design of a F/11-F/4.3 focal reducer for the Italian 3.5 m Galileo telescope. The system employs 6 spherical lenses and its image quality matches the requirements of a 1024^2^ array with 18.5μm pixels in both the imaging and spectroscopic (with grism) modes.

  7. Design of infrared zoom system with rotating lens group

    NASA Astrophysics Data System (ADS)

    Li, Yong; Yang, Changcheng; Li, Shenghui

    2008-03-01

    In surveillance applications there is a need for infrared zoom systems which give two fields of view. For such systems long operation range is the most critical parameter which is bound up with focal length and transmittance of systems. In this paper the design of an infrared zoom system with rotating lens group is described. Different from the conventional axially moving zoom systems, this system is based on a rotating mechanism consisting of two separated lenses. The system achieves dual FOVs due to different magnifications. In narrow field of view mode, the system has long focal length and higher transmittance because the rotating lens group is outside the optical path. The final design is an infrared zoom system operating in 3μm~5μm, with a F number of 4.0, EFL of 250mm/62.5mm. This paper contains the calculation of first-order parameter, the optimum design of rotating motion, the analysis of aberrations, MTF, and Narcissus, This designed system has diffraction limited image quality of in both FOVs.

  8. Designing a beam transport system for RHIC's electron lens

    SciTech Connect

    Gu, X.; Pikin, A.; Okamura, M.; Fischer, W.; Luo, Y.; Gupta, R.; Hock, J.; Raparia, D.

    2011-03-28

    We designed two electron lenses to apply head-on beam-beam compensation for RHIC; they will be installed near IP10. The electron-beam transport system is an important subsystem of the entire electron-lens system. Electrons are transported from the electron gun to the main solenoid and further to the collector. The system must allow for changes of the electron beam size inside the superconducting magnet, and for changes of the electron position by 5 mm in the horizontal- and vertical-planes.

  9. Solar energy system with pivoting lens and collector and conduit system therefor

    SciTech Connect

    Stark, V.

    1981-09-15

    A system in which solar energy is concentrated by an elongated lens in an elongated focus and collected in an elongated collector is disclosed. The lens is supported above the collector for pivotal movement with respect to the conduit about a first axis thereof to track the sun with the conduit remaining stationary. The collector further includes a container having an elongated solar energy transmitting aperture facing the lens along and adjacent to which the conduit extends, the container and lens being interconnected for pivotal movement with respect to the conduit about the first axis to maintain the aperture facing the lens with the conduit remaining stationary while the interconnected lens and container are pivoted. In one embodiment, the interconnected lens, container and conduit are also pivoted about a second axis transverse to the first axis. One embodiment of a conduit system includes an inner metal conduit having darkened outer surfaces to absorb solar energy and transmit heat to a fluid in the metal conduit. The metal conduit is enclosed by an enclosure and a dead space is provided around the inner metal conduit. In one embodiment, photovoltaic cells are installed in an inner transparent conduit in which the elongated focus of a fresnel lens is located. The inner conduit is enclosed by an outer transparent conduit of at least about 3 times larger diameter and a fluid is circulated in the outer conduit which will substantially transmit therethrough the luminous solar energy while absorbing substantial amounts of the infrared solar energy.

  10. Simultaneous Excitation of Multiple-Input Multiple-Output CFD-Based Unsteady Aerodynamic Systems

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.

    2007-01-01

    A significant improvement to the development of CFD-based unsteady aerodynamic reduced-order models (ROMs) is presented. This improvement involves the simultaneous excitation of the structural modes of the CFD-based unsteady aerodynamic system that enables the computation of the unsteady aerodynamic state-space model using a single CFD execution, independent of the number of structural modes. Four different types of inputs are presented that can be used for the simultaneous excitation of the structural modes. Results are presented for a flexible, supersonic semi-span configuration using the CFL3Dv6.4 code.

  11. Simultaneous Excitation of Multiple-Input Multiple-Output CFD-Based Unsteady Aerodynamic Systems

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.

    2008-01-01

    A significant improvement to the development of CFD-based unsteady aerodynamic reduced-order models (ROMs) is presented. This improvement involves the simultaneous excitation of the structural modes of the CFD-based unsteady aerodynamic system that enables the computation of the unsteady aerodynamic state-space model using a single CFD execution, independent of the number of structural modes. Four different types of inputs are presented that can be used for the simultaneous excitation of the structural modes. Results are presented for a flexible, supersonic semi-span configuration using the CFL3Dv6.4 code.

  12. Highly sensitive straightness measurement system using a ball-lens

    NASA Astrophysics Data System (ADS)

    Lee, Minho; Yang, Hyun-Ik; Cho, Nahm-Gyoo

    2016-01-01

    In this paper, a new and simple optical technique to accurately measure the straightness errors of a linear stage is proposed. To improve the performance, including the measurement sensitivity and resolution of the measurement system, and to simultaneously measure two-dimensional straightness errors (2D straightness errors), an optical system was designed using a laser, a retro-reflector, a ball-lens, and a two-dimensional position sensitive detector (2D PSD). The characteristics of the measurement system were analytically and experimentally investigated. A prototype measurement system was manufactured based on the investigated results, and the performances of this system have been tested. The measuring performance of the system was easily improved by about 12 times using the proposed technique and it can be further improved. It is shown that the proposed technique can easily and effectively improve the performance of a conventional straightness measurement system based on the geometric optical method using a PSD.

  13. An electro-active polymer based lens module for dynamically varying focal system

    NASA Astrophysics Data System (ADS)

    Yun, Sungryul; Park, Suntak; Nam, Saekwang; Park, Bongje; Park, Seung Koo; Mun, Seongcheol; Lim, Jeong Mook; Kyung, Ki-Uk

    2016-10-01

    We demonstrate a polymer-based active-lens module allowing a dynamic focus controllable optical system with a wide tunable range. The active-lens module is composed of parallelized two active-lenses with a convex and a concave shaped hemispherical lens structure, respectively. Under operation with dynamic input voltage signals, each active-lens produces translational movement bi-directionally responding to a hybrid driving force that is a combination of an electro-active response of a thin dielectric elastomer membrane and an electro-static attraction force. Since the proposed active lens module widely modulates a gap-distance between lens-elements, an optical system based on the active-lens module provides widely-variable focusing for selective imaging of objects in arbitrary position.

  14. Design of lens-hood in the space fisheye optical system

    NASA Astrophysics Data System (ADS)

    Zhu, Qing; Zhang, Zhao-hui; Zhang, Zhi; Yan, Aqi; Cao, Jian-zhong; Zhang, Kai-sheng

    2013-09-01

    Due to the extra wide field of view, fisheye optical systems are appropriately applied in space camera for scouting large-scale objects with near-distance. At the same time, because of the violent sunlight linger within the field of view more than other optical system and more stray light occur during the period, to design proper lens-hood can effectively reduce the sunshine time. Another distinct characteristic of fisheye optical system is the first protrude lens, which is contrived with negative focus to trace the ray with angle about even above 90 degree of incidence. Consequently, the first lens is in danger of damaging by scratching when operating the camera during the ground experiments without lens-hood. Whereas on account of the huge distortion which is the third mainly characteristic of fisheye optical system, to design appropriate lens-hood is a tough work comparing with other low-distortion optical system, especially for those whose half diagonal field is more than 90°. In this paper, an research carried out on the design lens-hood for fisheye is proposed. In the way of reverse ray-tracing, the location on the first lens and point-vector for each incident ray can be accurately calculated. Thus the incident ray intersecting the first lens corresponds to the boundary of the image sensor form the effective object space. According to the figure of the lens and the incident rays, the lens-hood can be confirmed. In the proposed method, a space fisheye lens is presented as a typical lens, whose horizontal field and vertical field are 134°, diagonal field is up to 192°, respectively. The results of design for the lens-hood show that the lingering time of sunshine is shorten because of obstructing some redundant sunlight, and the first outstanding lens are protected in the most degree.

  15. Conversion of the Aerodynamic Preliminary Analysis System (APAS) to an IBM PC Compatible Format

    NASA Technical Reports Server (NTRS)

    Kruep, John M.

    1995-01-01

    The conversion of the Aerodynamic Preliminary Analysis System (APAS) software from a Silicon Graphics UNIX-based platform to a DOS-based IBM PC compatible is discussed. Relevant background information is given, followed by a discussion of the steps taken to accomplish the conversion and a discussion of the type of problems encountered during the conversion. A brief comparison of aerodynamic data obtained using APAS with data from another source is also made.

  16. Wind Turbine Blade Design System - Aerodynamic and Structural Analysis

    NASA Astrophysics Data System (ADS)

    Dey, Soumitr

    2011-12-01

    The ever increasing need for energy and the depletion of non-renewable energy resources has led to more advancement in the "Green Energy" field, including wind energy. An improvement in performance of a Wind Turbine will enhance its economic viability, which can be achieved by better aerodynamic designs. In the present study, a design system that has been under development for gas turbine turbomachinery has been modified for designing wind turbine blades. This is a very different approach for wind turbine blade design, but will allow it to benefit from the features inherent in the geometry flexibility and broad design space of the presented system. It starts with key overall design parameters and a low-fidelity model that is used to create the initial geometry parameters. The low-fidelity system includes the axisymmetric solver with loss models, T-Axi (Turbomachinery-AXIsymmetric), MISES blade-to-blade solver and 2D wing analysis code XFLR5. The geometry parameters are used to define sections along the span of the blade and connected to the CAD model of the wind turbine blade through CAPRI (Computational Analysis PRogramming Interface), a CAD neutral API that facilitates the use of parametric geometry definition with CAD. Either the sections or the CAD geometry is then available for CFD and Finite Element Analysis. The GE 1.5sle MW wind turbine and NERL NASA Phase VI wind turbine have been used as test cases. Details of the design system application are described, and the resulting wind turbine geometry and conditions are compared to the published results of the GE and NREL wind turbines. A 2D wing analysis code XFLR5, is used for to compare results from 2D analysis to blade-to-blade analysis and the 3D CFD analysis. This kind of comparison concludes that, from hub to 25% of the span blade to blade effects or the cascade effect has to be considered, from 25% to 75%, the blade acts as a 2d wing and from 75% to the tip 3D and tip effects have to be taken into account

  17. RHIC electron lens beam transport system design considerations

    SciTech Connect

    Gu, X.; Pikin, A.; Okamura, M.; Fischer, W.; Luo, Y.; Gupta, R.; Hock, J.; Jain, A.; Raparia, D.

    2010-10-01

    To apply head-on beam-beam compensation for RHIC, two electron lenses are designed and will be installed at IP10. Electron beam transport system is one of important subsystem, which is used to transport electron beam from electron gun side to collector side. This system should be able to change beam size inside superconducting magnet and control beam position with 5 mm in horizontal and vertical plane. Some other design considerations for this beam transport system are also reported in this paper. The head-on beam-beam effect is one of important nonlinear source in storage ring and linear colliders, which have limited the luminosity improvement of many colliders, such as SppS, Tevatron and RHIC. In order to enhance the performance of colliders, beam-beam effects can be compensated with direct space charge compensation, indirect space charge compensation or betatron phase cancellation scheme. Like other colliders, indirect space charge compensation scheme (Electron Lens) was also proposed for Relativistic Heavy Ion Collider (RHIC) beam-beam compensation at Brookhaven National Laboratory. The two similar electron lenses are located in IR10 between the DX magnets. One RHIC electron lens consists of one DC electron gun, one superconducting magnet, one electron collector and beam transport system.

  18. The Shrinkage Model And Expert System Of Plastic Lens Formation

    NASA Astrophysics Data System (ADS)

    Chang, Rong-Seng

    1988-06-01

    Shrinkage causes both the appearance & dimension defects of the injected plastic lens. We have built up a model of state equations with the help of finite element analysis program to estimate the volume change (shrinkage and swelling) under the combinations of injection variables such as pressure and temperature etc., then the personal computer expert system has been build up to make that knowledge conveniently available to the user in the model design, process planning, process operation and some other work. The domain knowledge is represented by a R-graph (Relationship-graph) model which states the relationships of variables & equations. This model could be compare with other models in the expert system. If the user has better model to solve the shrinkage problem, the program will evaluate it automatically and a learning file will be trigger by the expert system to teach the user to update their knowledge base and modify the old model by this better model. The Rubin's model and Gilmore's model have been input to the expert system. The conflict has been solved both from the user and the deeper knowledge base. A cube prism and the convex lens examples have been shown in this paper. This program is written by MULISP language in IBM PC-AT. The natural language provides English Explaination of know why and know how and the automatic English translation for the equation rules and the production rules.

  19. Miniaturized unified imaging system using bio-inspired fluidic lens

    NASA Astrophysics Data System (ADS)

    Tsai, Frank S.; Cho, Sung Hwan; Qiao, Wen; Kim, Nam-Hyong; Lo, Yu-Hwa

    2008-08-01

    Miniaturized imaging systems have become ubiquitous as they are found in an ever-increasing number of devices, such as cellular phones, personal digital assistants, and web cameras. Until now, the design and fabrication methodology of such systems have not been significantly different from conventional cameras. The only established method to achieve focusing is by varying the lens distance. On the other hand, the variable-shape crystalline lens found in animal eyes offers inspiration for a more natural way of achieving an optical system with high functionality. Learning from the working concepts of the optics in the animal kingdom, we developed bio-inspired fluidic lenses for a miniature universal imager with auto-focusing, macro, and super-macro capabilities. Because of the enormous dynamic range of fluidic lenses, the miniature camera can even function as a microscope. To compensate for the image quality difference between the central vision and peripheral vision and the shape difference between a solid-state image sensor and a curved retina, we adopted a hybrid design consisting of fluidic lenses for tunability and fixed lenses for aberration and color dispersion correction. A design of the world's smallest surgical camera with 3X optical zoom capabilities is also demonstrated using the approach of hybrid lenses.

  20. Tolerance optimization of a mobile phone camera lens system.

    PubMed

    Jung, Sangjin; Choi, Dong-Hoon; Choi, Byung-Lyul; Kim, Ju Ho

    2011-08-10

    In the manufacturing process for the lens system of a mobile phone camera, various types of assembly and manufacturing tolerances, such as tilt and decenter, should be appropriately allocated. Because these tolerances affect manufacturing cost and the expected optical performance, it is necessary to choose a systematic design methodology for determining optimal tolerances. In order to determine the tolerances that minimize production cost while satisfying the reliability constraints on important optical performance indices, we propose a tolerance design procedure for a lens system. A tolerance analysis is carried out using Latin hypercube sampling for evaluating the expected optical performance. The tolerance optimization is carried out using a function-based sequential approximate optimization technique that can reduce the computational burden and smooth numerical noise occurring in the optimization process. Using the proposed design approach, the optimal production cost was decreased by 28.3% compared to the initial cost while satisfying all the constraints on the expected optical performance. We believe that the tolerance analysis and design procedure presented in this study can be applied to the tolerance optimization of other systems. PMID:21833148

  1. Automated Aerodynamic Optimization System for SST Wing-Body Configuration

    NASA Astrophysics Data System (ADS)

    Sasaki, Daisuke; Yang, Guowei; Obayashi, Shigeru

    In this paper, wing-body configurations for a next generation Supersonic Transport are designed by means of Multiobjective Evolutionary Algorithms. SST wing-body configurations are designed to reduce the aerodynamic drag and the sonic boom for supersonic flight. To lower the sonic boom intensity, the present objective function is to satisfy the equivalent area distribution for low sonic boom proposed by Darden. Wing and fuselage is defined by 131 design variables and optimized at the same time. Structured multiblock grids around SST wing-body configuration are generated automatically and an Euler solver is used to evaluate the aerodynamic performance of SST wing-body configuration. Compromised solutions are found as Pareto solutions. Although they have a variety of fuselage configurations, all of them have a similar wing planform due to the imposed constraints. The present results imply that a lifting surface should be distributed innovatively to match Darden’s distribution for low boom.

  2. Development of an aerodynamic measurement system for hypersonic rarefied flows.

    PubMed

    Ozawa, T; Fujita, K; Suzuki, T

    2015-01-01

    A hypersonic rarefied wind tunnel (HRWT) has lately been developed at Japan Aerospace Exploration Agency in order to improve the prediction of rarefied aerodynamics. Flow characteristics of hypersonic rarefied flows have been investigated experimentally and numerically. By conducting dynamic pressure measurements with pendulous models and pitot pressure measurements, we have probed flow characteristics in the test section. We have also improved understandings of hypersonic rarefied flows by integrating a numerical approach with the HRWT measurement. The development of the integration scheme between HRWT and numerical approach enables us to estimate the hypersonic rarefied flow characteristics as well as the direct measurement of rarefied aerodynamics. Consequently, this wind tunnel is capable of generating 25 mm-core flows with the free stream Mach number greater than 10 and Knudsen number greater than 0.1.

  3. Tunable-focus liquid lens system controlled by antagonistic winding-type SMA actuator.

    PubMed

    Son, Hyung-Min; Kim, Min Young; Lee, Yun-Jung

    2009-08-01

    A new tunable-focus liquid lens system is proposed that consists of a liquid-filled PDMS (polydimethylsiloxane) membrane, special liquid injection mechanism based on a cam structure, antagonistic winding-type SMA(shape memory alloys) actuator for changing the surface curvature of the membrane, and liquid injection control system, including a digital signal processing board and actuator driver board. The focal length of the liquid lens is adjusted by changing the radius of the curvature of the liquid lens through redistributing the liquid using an injection mechanism. In the case of liquid lens systems using conventional injection mechanisms, the nonlinear relationship between the focal length change and the actuator displacement makes it difficult to control the focal length of the lens system, as there is only a narrow control range for adjusting the focal length over a wide range. In addition, miniaturization of the lens system is difficult due to the requirement of bulky and heavy actuators, such as an electrical motor and pump[7]. Thus, a relatively light and small SMA actuator is proposed for a compact lens system. This paper then provides a detailed description of the proposed tunable-focus liquid lens system, and an experimental system is also implemented. Finally, the focusing performance of the proposed liquid lens system is analyzed, and its usefulness and effectiveness verified through a series of experiments.

  4. Bionic optical imaging system with aspheric solid-liquid mixed variable-focus lens

    NASA Astrophysics Data System (ADS)

    Du, Jia-Wei; Wang, Xuan-Yin; Liang, Dan

    2016-02-01

    A bionic optical imaging system with an aspheric solid-liquid mixed variable-focus lens was designed and fabricated. The entire system mainly consisted of a doublet lens, a solid-liquid mixed variable-focus lens, a connecting part, and a CCD imaging device. To mimic the structure of the crystalline lens, the solid-liquid mixed variable-focus lens consisted of a polydimethylsiloxane (PDMS) lens, a polymethyl methacrylate lens, and the liquid of ethyl silicone oil. By pumping liquid in or out of the cavity using a microinjector, the curvatures of the front and rear surfaces of the PDMS lens were varied, resulting in a change of focal length. The overall structure of the system was presented, as well as a detailed description of the solid-liquid mixed variable-focus lens, material, and fabrication process. Under different injection volumes, the deformation of the PDMS lens was measured and simulated, pictures were captured, and the optical performance was analyzed in simulations and experiments. The focal length of the system ranged from 25.05 to 14.61 mm, and the variation of the diopter was 28.5D, which was larger than that of the human eye.

  5. System and Method for Null-Lens Wavefront Sensing

    NASA Technical Reports Server (NTRS)

    Hill, Peter C. (Inventor); Thompson, Patrick L. (Inventor); Aronstein, David L. (Inventor); Bolcar, Matthew R. (Inventor); Smith, Jeffrey S. (Inventor)

    2015-01-01

    A method of measuring aberrations in a null-lens including assembly and alignment aberrations. The null-lens may be used for measuring aberrations in an aspheric optic with the null-lens. Light propagates from the aspheric optic location through the null-lens, while sweeping a detector through the null-lens focal plane. Image data being is collected at locations about said focal plane. Light is simulated propagating to the collection locations for each collected image. Null-lens aberrations may extracted, e.g., applying image-based wavefront-sensing to collected images and simulation results. The null-lens aberrations improve accuracy in measuring aspheric optic aberrations.

  6. The design of freeform surface lens for LED lighting system

    NASA Astrophysics Data System (ADS)

    Bao, Zhi-cong; Zhu, Jun; Xiong, Si-si; Jin, Guo-fan

    2013-08-01

    LED has many advantages, such as high luminous efficiency, small size, low-voltage DC drive, etc. so it has been widely used in many lighting situations. But in certain circumstances, such as uniform illumination requirements in the micro-display projection system, because LED has an analogous Lambertian radiation distribution resulting in its non-uniform light intensity, the secondary optical design should be done to achieve the specific illumination requirements. In this paper, a freeform surface lens is designed to obtain a square area with uniform illumination on the target plane with LED: Firstly, based on the law of conservation of energy, the source-target light energy mapping relationship between the incident plane and the target plane is achieved. Secondly, according to the vector form of Snell's law, the differential equations of the freeform surface are established. Finally, in order to solve the problem of surface discontinuity during the progress of designing the lens, the process of solving the differential equations is described in detail and the integrability condition is introduced to modify and adjust the points' position of freeform surface, thus reducing the errors accumulating during the progress of numerical calculation and improving the continuity of the freeform surface. By simulation, the continuity of the freeform surface and the uniform illumination improve a lot, so it is validated that the results meet the requirements and the design method using integrability condition can improve the continuity of the surface and lighting uniformity of the lighting system.

  7. Three-Dimensional Display System with Dual-Frequency Liquid-Crystal Varifocal Lens

    NASA Astrophysics Data System (ADS)

    Suyama, Shiro; Date, Munekazu; Takada, Hideaki

    2000-02-01

    A new volumetric three-dimensional (3-D) display system that provides all the visual cues to depth perception has been developed. This system provides flicker-free, large 3-D images of 250 mm in both diameter and depth with a viewing cone from {-}10\\circ to {+}10\\circ. The system is simply composed of a dual-frequency liquid-crystal (LC) varifocal lens (the key device), a two-dimensional display, and two fixed lens. The focal length of the LC varifocal lens can be continuously varied from {-}1.2 to {+}1.5 diopters (1/m) by changing the effective refractive index of LC@. Using a dual-frequency LC for the varifocal lens achieves sufficiently fast operation of at least 60 Hz for flicker-free moving 3-D images. The simple structure of our varifocal lens facilitates the fabrication of a large-diameter lens, resulting in large 3-D images with a sufficient viewing cone.

  8. The NSLS-II Multilayer Laue Lens Deposition System

    SciTech Connect

    Conley, R.; Bouet, N.; Biancarosa, J.; Shen, Q.; Boas, L.; Feraca, J.; Rosenbaum, L.

    2009-08-02

    The NSLS-II[1] program has a requirement for an unprecedented level of x-ray nanofocusing and has selected the wedged multilayer Laue lens[2,3] (MLL) as the optic of choice to meet this goal. In order to fabricate the MLL a deposition system is required that is capable of depositing depth-graded and laterally-graded multilayers with precise thickness control over many thousands of layers, with total film growth in one run up to 100m thick or greater. This machine design expounds on the positive features of a rotary deposition system[4] constructed previously for MLLs and will contain multiple stationary, horizontally-oriented magnetron sources where a transport will move a substrate back and forth in a linear fashion over shaped apertures at well-defined velocities to affect a multilayer coating.

  9. Comparison of piezoelectric systems and aerodynamic systems for aircraft vibration alleviation

    NASA Astrophysics Data System (ADS)

    Becker, Juergen; Luber, Wolfgang G.

    1998-06-01

    A comparison of active smart structure - piezoelectric control system and aerodynamic active systems for vibration alleviation and elastic mode damping of a military aircraft structure is presented. The vibration alleviation systems which are operative at flight in turbulence or during maneuvers at high incidence corresponding to severe buffeting conditions are under investigation by DASA as a part of research study on advanced aircraft structures. The active systems for elastic mode damping are designed as digital systems to provide vibration alleviation and have an interface to the flight control system (FCS) or are directly part of the FCS. The sensor concept of all different systems is the same as the sensor concept used for the FCS with the corresponding benefits of redundancy and safety. The design of systems and the comparisons of system properties are based on open and closed loop response calculations, performed with the dynamic model of the total aircraft including coupling of flight mechanics, structural dynamics, FCS dynamics and hydraulic actuator or piezo-actuator dynamics. Aerodynamic systems, like active foreplane and flap concepts, rudder and auxiliary rudder concepts, and piezoelectric systems, like piezo interface at the interconnection fin to rear fuselage and integrated piezo concepts are compared. Besides the essential effects on flexible aircraft mode stability and vibration alleviation factors system complexity and safety aspects are described.

  10. Quantifying Environmental and Line-of-Sight Effects in Models of Strong Gravitational Lens Systems

    NASA Astrophysics Data System (ADS)

    Keeton, Charles R.; McCully, Curtis; Wong, Kenneth C.; Zabludoff, Ann I.

    2016-01-01

    Mass outside a gravitational lens galaxy--around the lens or projected along the line of sight--can significantly affect the images produced by the lens. We quantify biases and uncertainties in lens-derived quantities, such as the Hubble constant, that are associated with these external effects. Specifically, we build realistic three-dimensional mass configurations and examine different treatments of the environmental and line-of-sight effects. Fitting a simple external shear in the lens plane can account for tidal stretching from perturbing galaxies at the lens redshift or in the background, but cannot fully reproduce the more complicated effects from foreground perturbers. That approach also requires a separate correction for external convergence. A better approach is to employ our new framework for multi-plane lensing, which recovers lens model parameters without bias and to a precision limited only by the lens profile degeneracy and measurement noise. Our framework now accounts for underdense regions along sightline, avoiding biases in the Hubble constant. We show that lens systems with large ellipticities are less sensitive to the lens profile degeneracy than rounder lenses, producing stronger constraints on the Hubble constant.

  11. Aerodynamic characterisation and trajectory simulations for the Ariane-5 booster recovery system

    NASA Astrophysics Data System (ADS)

    Meiboom, F. P.

    One of the most critical aspects of the early phases of the development of the Ariane-5 booster recovery system was the determination of the behavior of the booster during its atmospheric reentry, since this behavior determines the start conditions for the parachute system elements. A combination of wind-tunnel tests (subsonic and supersonic) and analytical methods was applied to define the aerodynamic characteristics of the booster. This aerodynamic characterization in combination with information of the ascent trajectory, atmospheric properties and booster mass and inertia were used as input for the 6-DOF trajectory simulations of the vehicle. Uncertainties in aerodynamic properties and deviations in atmospheric and booster properties were incorporated to define the range of initial conditions for the parachute system, utilizing stochastic (Monte-Carlo) methods.

  12. RF Lens-Embedded Massive MIMO Systems: Fabrication Issues and Codebook Design

    NASA Astrophysics Data System (ADS)

    Kwon, Taehoon; Lim, Yeon-Geun; Min, Byung-Wook; Chae, Chan-Byoung

    2016-07-01

    In this paper, we investigate a radio frequency (RF) lens-embedded massive multiple-input multiple-output (MIMO) system and evaluate the system performance of limited feedback by utilizing a technique for generating a suitable codebook for the system. We fabricate an RF lens that operates on a 77 GHz (mmWave) band. Experimental results show a proper value of amplitude gain and an appropriate focusing property. In addition, using a simple numerical technique--beam propagation method (BPM)--we estimate the power profile of the RF lens and verify its accordance with experimental results. We also design a codebook--multi-variance codebook quantization (MVCQ)--for limited feedback by considering the characteristics of the RF lens antenna for massive MIMO systems. Numerical results confirm that the proposed system shows significant performance enhancement over a conventional massive MIMO system without an RF lens.

  13. Extension of a nonlinear systems theory to general-frequency unsteady transonic aerodynamic responses

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.

    1993-01-01

    A methodology for modeling nonlinear unsteady aerodynamic responses, for subsequent use in aeroservoelastic analysis and design, using the Volterra-Wiener theory of nonlinear systems is presented. The methodology is extended to predict nonlinear unsteady aerodynamic responses of arbitrary frequency. The Volterra-Wiener theory uses multidimensional convolution integrals to predict the response of nonlinear systems to arbitrary inputs. The CAP-TSD (Computational Aeroelasticity Program - Transonic Small Disturbance) code is used to generate linear and nonlinear unit impulse responses that correspond to each of the integrals for a rectangular wing with a NACA 0012 section with pitch and plunge degrees of freedom. The computed kernels then are used to predict linear and nonlinear unsteady aerodynamic responses via convolution and compared to responses obtained using the CAP-TSD code directly. The results indicate that the approach can be used to predict linear unsteady aerodynamic responses exactly for any input amplitude or frequency at a significant cost savings. Convolution of the nonlinear terms results in nonlinear unsteady aerodynamic responses that compare reasonably well with those computed using the CAP-TSD code directly but at significant computational cost savings.

  14. 56 mm lens system for mapping displacement of centroids of stars.

    NASA Astrophysics Data System (ADS)

    Liu, Xinping

    1997-07-01

    A lens system configuration having six uncemented elements is discussed. The lens system is a 56 mm EFL with 11.3° field and a complicated Petzval configuration. It is different from the common lens used in imaging systems as this lens system is required to have a high resolving power. It was designed to determine the attitude of a space platform by detecting and mapping the geometric pattern of stars. Aberrations were controlled over a 0.46 ≡ 0.75 μm spectral region. It is required to deliver the geometric spot dispersion in the specific range at its focal surface and to lower the difference of displacements of centroids from the chief ray in the spectral range of interest. Only two kinds of common glass materials with low absorption and good properties were utilized in the lens system.

  15. Effect of vane opening on aerodynamic performance of the ram-rotor test system

    NASA Astrophysics Data System (ADS)

    Han, Ji-ang; Guan, Jian; Zhong, Jingjun; Yuan, Chenguang

    2016-06-01

    In order to research the influence of adjustable vane on the aerodynamic performance of the ram-rotor test system, FLUENT software has been adopted to simulate the flow passage of the ram-rotor test system numerically. The vane opening is controlled by changing the stagger angle of the vane blades. Results show that flow uniformity of vane outlet is influenced by the vane openings, which has an impact on the aerodynamic loss to some extent. Total pressure ratio, adiabatic efficiency and mass flow rate can be regulated by different openings of the vane. Compared with -8° vane opening, top efficiency of the ram-rotor increases by about 13.8% at +6° opening. And total pressure ratio drops by 5.87%. The rising opening increases the relative Mach number at inlet of the ram-rotor and weakens the intensity of the tip clearance leakage, which comes to a decreasing aerodynamic loss.

  16. Ring lens focusing and push-pull tracking scheme for optical disk systems

    NASA Technical Reports Server (NTRS)

    Gerber, R.; Zambuto, J.; Erwin, J. K.; Mansuripur, M.

    1993-01-01

    An experimental comparison of the ring lens and the astigmatic techniques of generating focus-error-signal (FES) in optical disk systems reveals that the ring lens generates a FES over two times steeper than that produced by the astigmat. Partly due to this large slope and, in part, because of its diffraction-limited behavior, the ring lens scheme exhibits superior performance characteristics. In particular the undesirable signal known as 'feedthrough' (induced on the FES by track-crossings during the seek operation) is lower by a factor of six compared to that observed with the astigmatic method. The ring lens is easy to align and has reasonable tolerance for positioning errors.

  17. A system for aerodynamic design and analysis of supersonic aircraft. Part 4: Test cases

    NASA Technical Reports Server (NTRS)

    Middleton, W. D.; Lundry, J. L.

    1980-01-01

    An integrated system of computer programs was developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. Representative test cases and associated program output are presented.

  18. Characterizing Aeroelastic Systems Using Eigenanalysis, Explicitly Retaining The Aerodynamic Degrees of Freedom

    NASA Technical Reports Server (NTRS)

    Heeg, Jennifer; Dowell, Earl H.

    2001-01-01

    Discrete time aeroelastic models with explicitly retained aerodynamic modes have been generated employing a time marching vortex lattice aerodynamic model. This paper presents analytical results from eigenanalysis of these models. The potential of these models to calculate the behavior of modes that represent damped system motion (noncritical modes) in addition to the simple harmonic modes is explored. A typical section with only structural freedom in pitch is examined. The eigenvalues are examined and compared to experimental data. Issues regarding the convergence of the solution with regard to refining the aerodynamic discretization are investigated. Eigenvector behavior is examined; the eigenvector associated with a particular eigenvalue can be viewed as the set of modal participation factors for that particular mode. For the present formulation of the equations of motion, the vorticity for each aerodynamic element appears explicitly as an element of each eigenvector in addition to the structural dynamic generalized coordinates. Thus, modal participation of the aerodynamic degrees of freedom can be assessed in M addition to participation of structural degrees of freedom.

  19. Assessment on EXPERT Descent and Landing System Aerodynamics

    NASA Astrophysics Data System (ADS)

    Wong, H.; Muylaert, J.; Northey, D.; Riley, D.

    2009-01-01

    EXPERT is a re-entry vehicle designed for validation of aero-thermodynamic models, numerical schemes in Computational Fluid Dynamics codes and test facilities for measuring flight data under an Earth re-entry environment. This paper addresses the design for the descent and landing sequence for EXPERT. It includes the descent sequence, the choice of drogue and main parachutes, and the parachute deployment condition, which can be supersonic or subsonic. The analysis is based mainly on an engineering tool, PASDA, together with some hand calculations for parachute sizing and design. The tool consists of a detailed 6-DoF simulation performed with the aerodynamics database of the vehicle, an empirical wakes model and the International Standard Atmosphere database. The aerodynamics database for the vehicle is generated by DNW experimental data and CFD codes within the framework of an ESA contract to CIRA. The analysis will be presented in terms of altitude, velocity, accelerations, angle-of- attack, pitch angle and angle of rigging line. Discussion on the advantages and disadvantages of each parachute deployment condition is included in addition to some comparison with the available data based on a Monte-Carlo method from a Russian company, FSUE NIIPS. Sensitivity on wind speed to the performance of EXPERT is shown to be strong. Supersonic deployment of drogue shows a better performance in stability at the expense of a larger G-load than those from the subsonic deployment of drogue. Further optimization on the parachute design is necessary in order to fulfill all the EXPERT specifications.

  20. Manufacturing injection-moleded Fresnel lens parquets for point-focus concentrating photovoltaic systems

    SciTech Connect

    Peters, E.M.; Masso, J.D.

    1995-10-01

    This project involved the manufacturing of curved-faceted, injection-molded, four-element Fresnel lens parquets for concentrating photovoltaic arrays. Previous efforts showed that high-efficiency (greater than 82%) Fresnel concentrators could be injection molded. This report encompasses the mold design, molding, and physical testing of a four-lens parquet for a solar photovoltaic concentrator system.

  1. On aerodynamic noises radiated by the pantograph system of high-speed trains

    NASA Astrophysics Data System (ADS)

    Yu, Hua-Hua; Li, Jia-Chun; Zhang, Hui-Qin

    2013-06-01

    Pantograph system of high-speed trains become significant source of aerodynamic noise when travelling speed exceeds 300 km/h. In this paper, a hybrid method of non-linear acoustic solver (NLAS) and Ffowcs Williams-Hawkings (FW-H) acoustic analogy is used to predict the aerodynamic noise of pantograph system in this speed range. When the simulation method is validated by a benchmark problem of flows around a cylinder of finite span, we calculate the near flow field and far acoustic field surrounding the pantograph system. And then, the frequency spectra and acoustic attenuation with distance are analyzed, showing that the pantograph system noise is a typical broadband one with most acoustic power restricted in the medium-high frequency range from 200 Hz to 5 kHz. The aerodynamic noise of pantograph systems radiates outwards in the form of spherical waves in the far field. Analysis of the overall sound pressure level (OASPL) at different speeds exhibits that the acoustic power grows approximately as the 4th power of train speed. The comparison of noise reduction effects for four types of pantograph covers demonstrates that only case 1 can lessen the total noise by about 3 dB as baffles on both sides can shield sound wave in the spanwise direction. The covers produce additional aerodynamic noise themselves in the other three cases and lead to the rise of OASPLs.

  2. Aerodynamic characteristics and design guidelines of push-pull ventilation systems.

    PubMed

    Huang, R F; Lin, S Y; Jan, S-Y; Hsieh, R H; Chen, Y-K; Chen, C-W; Yeh, W-Y; Chang, C-P; Shih, T-S; Chen, C-C

    2005-01-01

    Aerodynamic characteristics such as the flow patterns, velocity field, streamline evolutions, characteristic flow modes and characteristic flow regimes of the push-pull ventilation system are cross-examined by using the laser-light sheet smoked-flow visualization method and laser Doppler velocimetry. Four characteristic flow modes, which are denoted as dispersion, transition, encapsulation and strong suction, are identified in the domain of the push-jet and pull-flow velocities at various open-surface tank widths and rising gas velocities. It is argued phenomenologically, from the aerodynamic point of view, that operating the system in the strong suction regime would be a better strategy than operating it in other characteristic regimes for the consideration of capture efficiency. Design guidelines are developed and summarized based on the results obtained from this study. The regression formulas for calculating the critical values of the push-jet and the pull-flow velocities are provided for easy access. The sulfur hexafluoride tracer gas validation technique is performed to measure the capture efficiency. The results of tracer gas validations are consistent with those obtained from the aerodynamic visualization and measurements. The operation points obtained by employing the American Conference of Governmental Industrial Hygienists design criteria are compared with the results obtained in this study for both the aerodynamics and the capture efficiency. Methods for improving the capture efficiency and energy consumptions are suggested.

  3. A computational system for aerodynamic design and analysis of supersonic aircraft. Part 2: User's manual

    NASA Technical Reports Server (NTRS)

    Middleton, W. D.; Lundry, J. L.; Coleman, R. G.

    1976-01-01

    An integrated system of computer programs was developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. This user's manual contains a description of the system, an explanation of its usage, the input definition, and example output.

  4. System Dynamic Analysis of a Wind Tunnel Model with Applications to Improve Aerodynamic Data Quality

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph David

    1997-01-01

    The research investigates the effect of wind tunnel model system dynamics on measured aerodynamic data. During wind tunnel tests designed to obtain lift and drag data, the required aerodynamic measurements are the steady-state balance forces and moments, pressures, and model attitude. However, the wind tunnel model system can be subjected to unsteady aerodynamic and inertial loads which result in oscillatory translations and angular rotations. The steady-state force balance and inertial model attitude measurements are obtained by filtering and averaging data taken during conditions of high model vibrations. The main goals of this research are to characterize the effects of model system dynamics on the measured steady-state aerodynamic data and develop a correction technique to compensate for dynamically induced errors. Equations of motion are formulated for the dynamic response of the model system subjected to arbitrary aerodynamic and inertial inputs. The resulting modal model is examined to study the effects of the model system dynamic response on the aerodynamic data. In particular, the equations of motion are used to describe the effect of dynamics on the inertial model attitude, or angle of attack, measurement system that is used routinely at the NASA Langley Research Center and other wind tunnel facilities throughout the world. This activity was prompted by the inertial model attitude sensor response observed during high levels of model vibration while testing in the National Transonic Facility at the NASA Langley Research Center. The inertial attitude sensor cannot distinguish between the gravitational acceleration and centrifugal accelerations associated with wind tunnel model system vibration, which results in a model attitude measurement bias error. Bias errors over an order of magnitude greater than the required device accuracy were found in the inertial model attitude measurements during dynamic testing of two model systems. Based on a theoretical modal

  5. A passive autofocus system by using standard deviation of the image on a liquid lens

    NASA Astrophysics Data System (ADS)

    Rasti, Pejman; Kesküla, Arko; Haus, Henry; Schlaak, Helmut F.; Anbarjafari, Gholamreza; Aabloo, Alvo; Kiefer, Rudolf

    2015-04-01

    Today most of applications have a small camera such as cell phones, tablets and medical devices. A micro lens is required in order to reduce the size of the devices. In this paper an auto focus system is used in order to find the best position of a liquid lens without any active components such as ultrasonic or infrared. In fact a passive auto focus system by using standard deviation of the images on a liquid lens which consist of a Dielectric Elastomer Actuator (DEA) membrane between oil and water is proposed.

  6. Aerodynamic characteristics of the National Launch System (NLS) 1 1/2 stage launch vehicle

    NASA Technical Reports Server (NTRS)

    Springer, A. M.; Pokora, D. C.

    1994-01-01

    The National Aeronautics and Space Administration (NASA) is studying ways of assuring more reliable and cost effective means to space. One launch system studied was the NLS which included the l l/2 stage vehicle. This document encompasses the aerodynamic characteristics of the 1 l/2 stage vehicle. To support the detailed configuration definition two wind tunnel tests were conducted in the NASA Marshall Space Flight Center's 14x14-Inch Trisonic Wind Tunnel during 1992. The tests were a static stability and a pressure test, each utilizing 0.004 scale models. The static stability test resulted in the forces and moments acting on the vehicle. The aerodynamics for the reference configuration with and without feedlines and an evaluation of three proposed engine shroud configurations were also determined. The pressure test resulted in pressure distributions over the reference vehicle with and without feedlines including the reference engine shrouds. These pressure distributions were integrated and balanced to the static stability coefficients resulting in distributed aerodynamic loads on the vehicle. The wind tunnel tests covered a Mach range of 0.60 to 4.96. These ascent flight aerodynamic characteristics provide the basis for trajectory and performance analysis, loads determination, and guidance and control evaluation.

  7. Space Launch System Booster Separation Aerodynamic Database Development and Uncertainty Quantification

    NASA Technical Reports Server (NTRS)

    Chan, David T.; Pinier, Jeremy T.; Wilcox, Floyd J., Jr.; Dalle, Derek J.; Rogers, Stuart E.; Gomez, Reynaldo J.

    2016-01-01

    The development of the aerodynamic database for the Space Launch System (SLS) booster separation environment has presented many challenges because of the complex physics of the ow around three independent bodies due to proximity e ects and jet inter- actions from the booster separation motors and the core stage engines. This aerodynamic environment is dicult to simulate in a wind tunnel experiment and also dicult to simu- late with computational uid dynamics. The database is further complicated by the high dimensionality of the independent variable space, which includes the orientation of the core stage, the relative positions and orientations of the solid rocket boosters, and the thrust lev- els of the various engines. Moreover, the clearance between the core stage and the boosters during the separation event is sensitive to the aerodynamic uncertainties of the database. This paper will present the development process for Version 3 of the SLS booster separa- tion aerodynamic database and the statistics-based uncertainty quanti cation process for the database.

  8. An approach for the development of an aerodynamic-structural interaction numerical simulation for aeropropulsion systems

    SciTech Connect

    Naziar, J.; Couch, R.; Davis, M.

    1996-01-01

    Traditionally, aeropropulsion structural performance and aerodynamic performance have been designed separately and later mated together via flight testing. In today`s atmosphere of declining resources, it is imperative that more productive ways of designing and verifying aeropropulsion performance and structural interaction be made available to the aerospace industry. One method of obtaining a more productive design and evaluation capability is through the use of numerical simulations. Currently, Lawrence Livermore National Laboratory has developed a generalized fluid/structural interaction code known as ALE3D. This code is capable of characterizing fluid and structural interaction for components such as the combustor, fan/stators, inlet and/or nozzles. This code solves the 3D Euler equations and has been applied to several aeropropulsion applications such as a supersonic inlet and a combustor rupture simulation. To characterize aerodynamic-structural interaction for rotating components such as the compressor, appropriate turbomachinery simulations would need to be implemented within the ALE3D structure. The Arnold Engineering Development Center is currently developing a three-dimensional compression system code known as TEACC (Turbine Engine Analysis Compressor Code). TEACC also solves the 3D Euler equations and is intended to simulate dynamic behavior such as inlet distortion, surge or rotating stall. The technology being developed within the TEACC effort provides the necessary turbomachinery simulation for implementation into ALE3D. This paper describes a methodology to combine three-dimensional aerodynamic turbomachinery technology into the existing aerodynamic-structural interaction simulation, ALE3D to obtain the desired aerodynamic and structural integrated simulation for an aeropropulsion system.

  9. A PDMS-based cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems.

    PubMed

    Lin, Bor-Shyh; Yang, Yu-Ching; Ho, Chong-Yi; Yang, Han-Yu; Wang, Hsiang-Yu

    2014-02-13

    Microfluidic systems based on fluorescence detection have been developed and applied for many biological and chemical applications. Because of the tiny amount of sample in the system; the induced fluorescence can be weak. Therefore, most microfluidic systems deploy multiple optical components or sophisticated equipment to enhance the efficiency of fluorescence detection. However, these strategies encounter common issues of complex manufacturing processes and high costs. In this study; a miniature, cylindrical and hybrid lens made of polydimethylsiloxane (PDMS) to improve the fluorescence detection in microfluidic systems is proposed. The hybrid lens integrates a laser focusing lens and a fluorescence collecting lens to achieve dual functions and simplify optical setup. Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components. The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red. The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively. The hybrid lens is further applied to the detection of Nile red-labeled Chlorella vulgaris cells and it increases both signal intensity and detection sensitivity by more than 520%. The proposed hybrid lens also dramatically reduces the variation in detected signal caused by the deviation in incident angle of excitation light.

  10. Abort System Using Supersonic Aerodynamic Interaction for Capsule-Type Space Transportation System

    NASA Astrophysics Data System (ADS)

    小澤, 啓伺; 北村, 圭一; 花井, 勝祥; 三好, 理也; 森, 浩一; 中村, 佳朗

    The space transportation system using capsule/rocket configurations such as Apollo and Soyuz are simple compared with Space Shuttle, and have several merits from the viewpoint of reliability. The capsule/rocket system will take over the Space Shuttle, after it retires in 2010. As the Space Shuttle accidents had been caused by several factors, e.g., aerodynamic interaction of shock waves ahead of its wing, advanced abort systems such as LAS (Launch Abort System) are required for the capsule/rocket system. In the present study, as a baseline configuration, a combination of a cone and a cylinder is employed as a CEV (Crew Exploration Vehicle), which consists of a capsule (LAV: Launch Abort Vehicle) and a rocket (SM: Service Module). By changing the relative position of the two components as well as the profile area of the rocket, their effects on the capsule/rocket aerodynamic interaction and characteristics (drag and pitching moment) are experimentally and numerically investigated at a supersonic speed (M∞ = 3.0). It is found from the results that the clearance have little effects on the flow field for the case of the baseline configuration. The capsule always showed a positive drag (CD = 0.34), which means that thrust is required to overcome the drag. Otherwise the capsule will recontact the rocket. However in the case where the rocket contact area is 2.2 times as large as the capsule profile, more favorable effects were obtained. Especially in the case of a certain clearance (h/D = 0.40), the drag coefficient of the capsule is CD = -0.35, which means that the capsule suffers a thrust force from the aerodynamic interaction. Under this condition, if capsule has a pitch angle with 5 degrees instantaneously, then pitching moment coefficient becomes CMp = -0.41 therefore capsule stabilize. However, in the case of a very small clearance (h/D ∝ 0.00), the flow becomes unsteady involving pulsating shock wave, leading to a potentially risky separation of the capsule.

  11. Prospects for Integrating a Hollow Electron Lens into the LHC Collimation System

    SciTech Connect

    Smith, Jeffrey Claiborne; Assmann, Ralph; Previtali, Valentina; Shiltsev, Vladimir; Valishev, Alexander; /CERN /Fermilab

    2009-08-03

    It has been proposed to use a hollow electron lens with the LHC beam collimation system [1]. The hollow electron beam would be used as a beam scraper and positioned at a closer sigma than the primary collimators to increase the halo particle diffusion rate striking the primaries. In this paper we use multi-turn beam tracking simulations to analyze the effectiveness of such a lens when integrated into the LHC collimation system.

  12. Calibration of a trinocular system formed with wide angle lens cameras.

    PubMed

    Ricolfe-Viala, Carlos; Sanchez-Salmeron, Antonio-Jose; Valera, Angel

    2012-12-01

    To obtain 3D information of large areas, wide angle lens cameras are used to reduce the number of cameras as much as possible. However, since images are high distorted, errors in point correspondences increase and 3D information could be erroneous. To increase the number of data from images and to improve the 3D information, trinocular sensors are used. In this paper a calibration method for a trinocular sensor formed with wide angle lens cameras is proposed. First pixels locations in the images are corrected using a set of constraints which define the image formation in a trinocular system. When pixels location are corrected, lens distortion and trifocal tensor is computed.

  13. A program to evaluate a control system based on feedback of aerodynamic pressure differentials

    NASA Technical Reports Server (NTRS)

    Levy, D. W.; Finn, P.; Roskam, J.

    1981-01-01

    The use of aerodynamic pressure differentials to position a control surface is evaluated. The system is a differential pressure command loop, analogous to a position command loop, where the surface is commanded to move until a desired differential pressure across the surface is achieved. This type of control is more direct and accurate because it is the differential pressure which causes the control forces and moments. A frequency response test was performed in a low speed wind tunnel to measure the performance of the system. Both pressure and position feedback were tested. The pressure feedback performed as well as position feedback implying that the actuator, with a break frequency on the order of 10 Rad/sec, was the limiting component. Theoretical considerations indicate that aerodynamic lags will not appear below frequencies of 50 Rad/sec, or higher.

  14. Finite Difference Time Domain Analysis of Underwater Acoustic Lens System for Ambient Noise Imaging

    NASA Astrophysics Data System (ADS)

    Mori, Kazuyoshi; Miyazaki, Ayano; Ogasawara, Hanako; Yokoyama, Tomoki; Nakamura, Toshiaki

    2006-05-01

    Much attention has been paid to the new idea of detecting objects using ocean ambient noise. This concept is called ambient noise imaging (ANI). In this study, sound fields focused by an acoustic lens system constructed with a single biconcave lens were analyzed using the finite difference time domain (FDTD) method for realizing an ANI system. The size of the lens aperture that would have sufficient resolution—for example, the beam width is 1° at 60 kHz—was roughly determined by comparing the image points and -3 dB areas of sound pressure fields generated by lenses with various apertures. Then, in another FDTD analysis, we successfully used a lens with a determined aperture to detect rigid target objects in an acoustic noise field generated by a large number of point sources.

  15. Propulsion System Airframe Integration Issues and Aerodynamic Database Development for the Hyper-X Flight Research Vehicle

    NASA Technical Reports Server (NTRS)

    Engelund, Walter C.; Holland, Scott D.; Cockrell, Charles E., Jr.; Bittner, Robert D.

    1999-01-01

    NASA's Hyper-X Research Vehicle will provide a unique opportunity to obtain data on an operational airframe integrated scramjet propulsion system at true flight conditions. The airframe integrated nature of the scramjet engine with the Hyper-X vehicle results in a strong coupling effect between the propulsion system operation and the airframe s basic aerodynamic characteristics. Comments on general airframe integrated scramjet propulsion system effects on vehicle aerodynamic performance, stability, and control are provided, followed by examples specific to the Hyper-X research vehicle. An overview is provided of the current activities associated with the development of the Hyper-X aerodynamic database, including wind tunnel test activities and parallel CFD analysis efforts. A brief summary of the Hyper-X aerodynamic characteristics is provided, including the direct and indirect effects of the airframe integrated scramjet propulsion system operation on the basic airframe stability and control characteristics.

  16. Numerical simulations of interactions among aerodynamics, structural dynamics, and control systems

    NASA Astrophysics Data System (ADS)

    Preidikman, Sergio

    A robust technique for performing numerical simulations of nonlinear unsteady aeroelastic behavior is developed. The technique is applied to long-span bridges and the wing of a modern business jet. The heart of the procedure is combining the aerodynamic and structural models. The aerodynamic model is a general unsteady vortex-lattice method. The structural model for the bridges is a rigid roadbed supported by linear and torsional springs. For the aircraft wing, the structural model is a cantilever beam with rigid masses attached at various positions along the span; it was generated with the NASTRAN program. The structure, flowing air, and control devices are considered to be the elements of a single dynamic system. All the governing equations are integrated simultaneously and interactively in the time domain; a predictor-corrector method was adapted to perform this integration. For long-span bridges, the simulation predicts the onset of flutter accurately, and the numerical results strongly suggest that an actively controlled wing attached below the roadbed can easily suppress the wind-excited oscillations. The governing equations for a proposed passive system were developed. The wing structure is modelled with finite elements. The deflections are expressed as an expansion in terms of the free-vibration modes. The time-dependent coefficients are the generalized coordinates of the entire dynamic system. The concept of virtual work was extended to develop a method to transfer the aerodynamic loads to the structural nodes. Depending on the speed of the aircraft, the numerical results show damped responses to initial disturbances (although there are no viscous terms in either the aerodynamic or structural model), merging of modal frequencies, the development of limit-cycle oscillations, and the occurrence of a supercritical Hopf bifurcation leading to motion on a torus.

  17. The EarLens System: New Sound Transduction Methods

    PubMed Central

    Perkins, Rodney; Fay, Jonathan P.; Rucker, Paul; Rosen, Micha; Olson, Lisa; Puria, Sunil

    2010-01-01

    The hypothesis is tested that an open-canal hearing device, with a microphone in the ear canal, can be designed to provide amplification over a wide bandwidth and without acoustic feedback. In the design under consideration, a transducer consisting of a thin silicone platform with an embedded magnet is placed directly on the tympanic membrane. Sound picked up by a microphone in the ear canal, including sound-localization cues thought to be useful for speech perception in noisy environments, is processed and amplified, and then used to drive a coil near the tympanic-membrane transducer. The perception of sound results from the vibration of the transducer in response the electromagnetic field produced by the coil. Sixteen subjects (ranging from normal-hearing to moderately hearing-impaired) wore this transducer for up to a ten-month period, and were monitored for any adverse reactions. Three key functional characteristics were measured: 1) the maximum equivalent pressure output (MEPO) of the transducer; 2) the feedback gain margin (GM), which describes the maximum allowable gain before feedback occurs; and 3) the tympanic-membrane damping effect (DTM), which describes the change in hearing level due to placement of the transducer on the eardrum. Results indicate that the tympanic-membrane transducer remains in place and is well tolerated. The system can produce sufficient output to reach threshold for those with as much as 60 dBHL of hearing impairment for up to 8 kHz in 86% of the study population, and up to 11.2 kHz in 50% of the population. The feedback gain margin is on average 30 dB except at the ear canal resonance frequencies of 3 and 9 kHz, where the average was reduced to 12 dB and 23 dB respectively. The average value of DTM is close to 0 dB everywhere except in the 2–4 kHz range, where it peaks at 8 dB. A new alternative system that uses photonic energy to transmit both the signal and power to a photodiode and micro-actuator on an EarLens platform is

  18. Evaluating Directional Resolution of Aplanatic Acoustic Lens for Designing Ambient Noise Imaging System

    NASA Astrophysics Data System (ADS)

    Mori, Kazuyoshi; Ogasawara, Hanako; Nakamura, Toshiaki; Sato, Yuji; Tsuchiya, Takenobu; Endoh, Nobuyuki

    2009-07-01

    In our previous studies, it was verified that a spherical biconcave lens with an aperture diameter of 2.0 m has a sufficient directional resolution (e.g., a beam width of 1° at 60 kHz) for realizing an ambient noise imaging (ANI) system. In this study, an aplanatic lens that corrects both spherical and coma aberrations with the same aperture was designed for an ANI system, and its directional resolution was evaluated. First, in order to predict the resolution, we performed a numerical analysis using the finite difference time domain (FDTD) method. Second, the numerical analysis results were verified by a small-scale trial of one-fifth of full size in a water tank. The shapes of the -3 dB areas were similar between the numerical analysis and experimental results at small incidence angles, and the -3 dB areas do not overlap at 1° increments of incidence angle. The resolution of the aplanatic lens was closer to that of an ideal lens than to that of the spherical lens. Finally, it was satisfied that the present lens has sufficient directional resolution for use in an ANI system.

  19. Aerodynamic preliminary analysis system. Part 2: User's manual and program description

    NASA Technical Reports Server (NTRS)

    Divan, P.; Dunn, K.; Kojima, J.

    1978-01-01

    A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple nonplanar surfaces of arbitrary planform and open or closed slender bodies or noncircular contour are analyzed. Longitudinal and lateral-directional static and rotary derivative solutions are generated. The analysis is implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

  20. Dynamic interactions between hypersonic vehicle aerodynamics and propulsion system performance

    NASA Technical Reports Server (NTRS)

    Flandro, G. A.; Roach, R. L.; Buschek, H.

    1992-01-01

    Described here is the development of a flexible simulation model for scramjet hypersonic propulsion systems. The primary goal is determination of sensitivity of the thrust vector and other system parameters to angle of attack changes of the vehicle. Such information is crucial in design and analysis of control system performance for hypersonic vehicles. The code is also intended to be a key element in carrying out dynamic interaction studies involving the influence of vehicle vibrations on propulsion system/control system coupling and flight stability. Simple models are employed to represent the various processes comprising the propulsion system. A method of characteristics (MOC) approach is used to solve the forebody and external nozzle flow fields. This results in a very fast computational algorithm capable of carrying out the vast number of simulation computations needed in guidance, stability, and control studies. The three-dimensional fore- and aft body (nozzle) geometry is characterized by the centerline profiles as represented by a series of coordinate points and body cross-section curvature. The engine module geometry is represented by an adjustable vertical grid to accommodate variations of the field parameters throughout the inlet and combustor. The scramjet inlet is modeled as a two-dimensional supersonic flow containing adjustable sidewall wedges and multiple fuel injection struts. The inlet geometry including the sidewall wedge angles, the number of injection struts, their sweepback relative to the vehicle reference line, and strut cross-section are user selectable. Combustion is currently represented by a Rayleigh line calculation including corrections for variable gas properties; improved models are being developed for this important element of the propulsion flow field. The program generates (1) variation of thrust magnitude and direction with angle of attack, (2) pitching moment and line of action of the thrust vector, (3) pressure and temperature

  1. Wake imaging system applications at the Boeing Aerodynamics Laboratory

    NASA Astrophysics Data System (ADS)

    Crowder, O. P.

    1985-10-01

    The wake imaging system (WIS) for rapid mappings of wind-tunnel model flowfields is described and a summary of recent results is presented. Three different types of systems are discussed. These are: (1) photographic WIS in low-speed wind tunnels, (2) computer graphics WIS in transonic wind tunnels, and (3) flying-strut traverser for large low-speed wind tunnels. In addition, progress toward developing a low intrusive WIS for high-pressure transonic wind tunnels and for flight test applications is described.

  2. A system for aerodynamically sizing ultrafine environmental radioactive particles

    SciTech Connect

    Olawoyin, L.

    1995-09-01

    The unattached environmental radioactive particles/clusters, produced mainly by {sup 222}Rn in indoor air, are usually few nanometers in size. The inhalation of these radioactive clusters can lead to deposition of radioactivity on the mucosal surface of the tracheobronchial tree. The ultimate size of the cluster together with the flow characteristics will determine the depositional site in the human lung and thus, the extent of damage that can be caused. Thus, there exists the need for the determination of the size of the radioactive clusters. However, the existing particle measuring device have low resolution in the sub-nanometer range. In this research, a system for the alternative detection and measurement of the size of particles/cluster in the less than 2 nm range have been developed. The system is a one stage impactor which has a solid state spectrometer as its impaction plate. It`s major feature is the nozzle-to-plate separation, L. The particle size collected changes with L and thus, particle size spectroscopy is achieved by varying L. The number of collected particles is determined by alpha spectroscopy. The size-discriminating ability of the system was tested with laboratory generated radon particles and it was subsequently used to characterize the physical (size) changes associated with the interaction of radon progeny with water vapor and short chain alcohols in various support gases. The theory of both traditional and high velocity jet impactors together with the design and evaluation of the system developed in this study are discussed in various chapters of this dissertation. The major results obtained in the course of the study are also presented.

  3. An Efficient Multiblock Method for Aerodynamic Analysis and Design on Distributed Memory Systems

    NASA Technical Reports Server (NTRS)

    Reuther, James; Alonso, Juan Jose; Vassberg, John C.; Jameson, Antony; Martinelli, Luigi

    1997-01-01

    The work presented in this paper describes the application of a multiblock gridding strategy to the solution of aerodynamic design optimization problems involving complex configurations. The design process is parallelized using the MPI (Message Passing Interface) Standard such that it can be efficiently run on a variety of distributed memory systems ranging from traditional parallel computers to networks of workstations. Substantial improvements to the parallel performance of the baseline method are presented, with particular attention to their impact on the scalability of the program as a function of the mesh size. Drag minimization calculations at a fixed coefficient of lift are presented for a business jet configuration that includes the wing, body, pylon, aft-mounted nacelle, and vertical and horizontal tails. An aerodynamic design optimization is performed with both the Euler and Reynolds Averaged Navier-Stokes (RANS) equations governing the flow solution and the results are compared. These sample calculations establish the feasibility of efficient aerodynamic optimization of complete aircraft configurations using the RANS equations as the flow model. There still exists, however, the need for detailed studies of the importance of a true viscous adjoint method which holds the promise of tackling the minimization of not only the wave and induced components of drag, but also the viscous drag.

  4. Aerodynamic Interference Due to MSL Reaction Control System

    NASA Technical Reports Server (NTRS)

    Dyakonov, Artem A.; Schoenenberger, Mark; Scallion, William I.; VanNorman, John W.; Novak, Luke A.; Tang, Chun Y.

    2009-01-01

    An investigation of effectiveness of the reaction control system (RCS) of Mars Science Laboratory (MSL) entry capsule during atmospheric flight has been conducted. The reason for the investigation is that MSL is designed to fly a lifting actively guided entry with hypersonic bank maneuvers, therefore an understanding of RCS effectiveness is required. In the course of the study several jet configurations were evaluated using Langley Aerothermal Upwind Relaxation Algorithm (LAURA) code, Data Parallel Line Relaxation (DPLR) code, Fully Unstructured 3D (FUN3D) code and an Overset Grid Flowsolver (OVERFLOW) code. Computations indicated that some of the proposed configurations might induce aero-RCS interactions, sufficient to impede and even overwhelm the intended control torques. It was found that the maximum potential for aero-RCS interference exists around peak dynamic pressure along the trajectory. Present analysis largely relies on computational methods. Ground testing, flight data and computational analyses are required to fully understand the problem. At the time of this writing some experimental work spanning range of Mach number 2.5 through 4.5 has been completed and used to establish preliminary levels of confidence for computations. As a result of the present work a final RCS configuration has been designed such as to minimize aero-interference effects and it is a design baseline for MSL entry capsule.

  5. Long-range visible light communication system based on LED collimating lens

    NASA Astrophysics Data System (ADS)

    Chen, Yingcong; Wen, Shangsheng; Wu, Yuxiang; Ren, Yuanyuan; Guan, Weipeng; Zhou, Yunlin

    2016-10-01

    An advanced visible light communication (VLC) system is proposed for long-range VLC, such as marine communication. The design of the system is conducted into two parts. Firstly, we design and optimize a collimating lens for the optical antenna by using Taguchi method. The lighting effects and optical power of the receiving end in different distances are simulated by TracePro software. Then, the long-range VLC channel is reconstructed by integrating the influence of the atmospheric attenuation and frequency response. The performance of the OOK coding VLC system is tested by Matlab software. The results show that: the emitting angle of the optimized collimating lens is 1.7°. By using 1 W LED and collimating lens as an optical antenna, the system can achieve a data rate of 210 Mbit/s at a bit error rate of 10-3 in 90 m.

  6. Construction of a 300-keV compact ion microbeam system with a three-stage acceleration lens

    NASA Astrophysics Data System (ADS)

    Ishii, Yasuyuki; Ohkubo, Takeru; Kojima, Takuji; Kamiya, Tomihiro

    2014-08-01

    Hydrogen ion microbeams were experimentally formed at beam energies below 150 keV using a 300-keV compact microbeam system that was constructed at the Japan Atomic Energy Agency. This paper is a preliminary report on the performance of the three-stage acceleration lens used in the compact microbeam system. This system consists of a three-stage acceleration lens and a plasma-type ion source. Since the three-stage acceleration lens was designed to simultaneously accelerate and focus the ion beam, the compact microbeam system is only about 1-m high and can be placed in a small experimental room. To evaluate the effectiveness of the three-stage acceleration lens, experimentally measured beam sizes are compared with theoretically calculated ones. The calculated and measured beam sizes were consistent within 10%. This shows that the three-stage acceleration lens is effective as a focusing lens for forming microbeams.

  7. Integrated aerodynamic and dynamic optimization of tiltrotor wing and rotor systems

    NASA Astrophysics Data System (ADS)

    Orr, Stanley

    Rotorcraft analysis and design must account for interdisciplinary interactions, especially between aerodynamics, structural, and dynamics responses. In this design domain, the work of disciplinary experts is segregated to a large extent. Furthermore, the design of subsystems is also segregated. In this environment it is difficult to account for interdisciplinary interactions and exploit the coupling between sub systems. This work examined the multidisciplinary nature of a tiltrotor aircraft focusing on the aerodynamic design of the rotor, and the structural and dynamic design of the rotor and wing systems. The design was considered to be in the preliminary design phase, after the basic configuration is set and before fine details of the design are defined. Attention was focused on developing an optimization problem formulation that was sufficiently complete so that optimization technologies and heuristic strategies could be developed and evaluated for tiltrotor design. Furthermore the level of detail in the analysis was consistent with the phase of design. Coupling between the aerodynamic, dynamic, and structural design was shown to be significant. Additionally, the coupling between the design of the wing and rotor systems was also significant, so that an integrated design was required. This work developed integrated design strategies for solving this design problem efficiently, while exploiting the couplings. Sum of system weights was the main objective along with vibratory rotor hub loads while hover performance, strength, frequency placement, and stability were constraints. Design variables included blade aerodynamic planform and twist as well as the details of composite D-spar blade sections, and details of composite torque-box wing sections. Cruise mode rotor speed and wing thickness were also included as design variables. A genetic algorithm based collaborative optimization was used as the solution framework for the global optimal search. The problem was

  8. The effects of unsteady aerodynamics on single and clustered parachute systems

    SciTech Connect

    Waye, D.E.; Johnson, D.W.

    1989-01-01

    A study was performed to evaluate the performance of equivalent drag area single parachute systems and cluster parachute systems during the early inflation and initial deceleration phase. Analytical work showed that the cluster system could exhibit better performance during this unsteady aerodynamic phase due to a significant decrease in the apparent mass of air influenced by the parachutes. Two test programs have been performed in support of these assumptions. The first compared systems with parachute drag areas of approximately 750 ft/sup 2/ and a payload of 2400 lbs. The cluster system exhibited increased performance and less susceptibility to parachute collapse due to wake recontact. The second series compared systems with parachute drag areas of approximately 260 ft/sup 2/ with a payload of 800 lbs. The advantages of the cluster system were less apparent but performance was moderately improved. 4 refs., 7 figs.

  9. A capacitor-based sensor and a contact lens sensing system for intraocular pressure monitoring

    NASA Astrophysics Data System (ADS)

    Chiou, Jin-Chern; Huang, Yu-Chieh; Yeh, Guan-Ting

    2016-01-01

    This study proposes a capacitor-based sensor on a soft contact lens for the measurement of intraocular pressure (IOP). The sensor was designed and fabricated via microelectromechanical system fabrication technologies. The soft contact lens is designed to be worn on a cornea such that the curvature of the contact lens corresponds substantially to that of the cornea. In addition, the contact lens was fabricated via a cast-molding method using poly-2-hydroxyethyl methacrylate to achieve a lens with high oxygen permeability, which can be worn comfortably for a long time. An IOP sensor prototype was implemented, which exhibited 1.2239 pF mmHg-1 (13,171 ppm mmHg-1) sensitivity during measurements of an artificial anterior chamber at pressures between 18 and 30 mmHg. The results indicate that the developed capacitor-based IOP sensor exhibited high stability and reproducibility in a series of measurements performed under various pressures. The capacitance of the proposed IOP sensor can successfully be converted into a digital value via a capacitor-to-digital converter and be transmitted via a commercial wireless telemetry system in this study.

  10. Aerodynamic design of a Coanda induced force and thruster anti-torque system

    NASA Technical Reports Server (NTRS)

    Velkoff, Henry R.; Tung, Chee

    1991-01-01

    A general method of analysis of the external and internal aerodynamics of a generic Coanda induced circulation anti-torque system is presented. The technique gives moment about the yaw axis and download induced on the boom as well as the force developed by an aft jet. The external flows including downwash, wake swirl and the boom circulation are considered. The internal flow and losses through the duct, fan, blown slots, cascades and nozzle are considered on a step-by-step basis. Limited comparison is made with open data where available.

  11. Integration of a supersonic unsteady aerodynamic code into the NASA FASTEX system

    NASA Technical Reports Server (NTRS)

    Appa, Kari; Smith, Michael J. C.

    1987-01-01

    A supersonic unsteady aerodynamic loads prediction method based on the constant pressure method was integrated into the NASA FASTEX system. The updated FASTEX code can be employed for aeroelastic analyses in subsonic and supersonic flow regimes. A brief description of the supersonic constant pressure panel method, as applied to lifting surfaces and body configurations, is followed by a documentation of updates required to incorporate this method in the FASTEX code. Test cases showing correlations of predicted pressure distributions, flutter solutions, and stability derivatives with available data are reported.

  12. Horizontal Axis Wind Energy Conversion System with Aerodynamic Blade Pitch Control

    SciTech Connect

    Rossman, W. E.

    1983-12-27

    The horizontal axis wind turbine converts wind into electrical energy and includes a pitch control vane with a flyweight mechanism on each rotor blade to provide aerodynamic efficiency at operating wind velocities, near constant speed and zero lift pitch of the rotor blades when speeds exceed the design speed of the system. A gravity neutralization means composed of a bevel gear and pinions couples the blades together while a flyweight arrangement connected to the bevel gear acts to neutralize centrifugal torque on the blades.

  13. An RFID-based on-lens sensor system for long-term IOP monitoring.

    PubMed

    Hsu, Shun-Hsi; Chiou, Jin-Chern; Liao, Yu-Te; Yang, Tzu-Sen; Kuei, Cheng-Kai; Wu, Tsung-Wei; Huang, Yu-Chieh

    2015-01-01

    In this paper, an RFID-based on-lens sensor system is proposed for noninvasive long-term intraocular pressure monitoring. The proposed sensor IC, fabricated in a 0.18um CMOS process, consists of capacitive sensor readout circuitry, RFID communication circuits, and digital processing units. The sensor IC is integrated with electroplating capacitive sensors and a receiving antenna on the contact lens. The sensor IC can be wirelessly powered, communicate with RFID compatible equipment, and perform IOP measurement using on-lens capacitive sensor continuously from a 2cm distance while the incident power from an RFID reader is 20 dBm. The proposed system is compatible to Gen2 RFID protocol, extending the flexibility and reducing the self-developed firmware efforts. PMID:26738033

  14. An RFID-based on-lens sensor system for long-term IOP monitoring.

    PubMed

    Hsu, Shun-Hsi; Chiou, Jin-Chern; Liao, Yu-Te; Yang, Tzu-Sen; Kuei, Cheng-Kai; Wu, Tsung-Wei; Huang, Yu-Chieh

    2015-01-01

    In this paper, an RFID-based on-lens sensor system is proposed for noninvasive long-term intraocular pressure monitoring. The proposed sensor IC, fabricated in a 0.18um CMOS process, consists of capacitive sensor readout circuitry, RFID communication circuits, and digital processing units. The sensor IC is integrated with electroplating capacitive sensors and a receiving antenna on the contact lens. The sensor IC can be wirelessly powered, communicate with RFID compatible equipment, and perform IOP measurement using on-lens capacitive sensor continuously from a 2cm distance while the incident power from an RFID reader is 20 dBm. The proposed system is compatible to Gen2 RFID protocol, extending the flexibility and reducing the self-developed firmware efforts.

  15. Development of the Dual Aerodynamic Nozzle Model for the NTF Semi-Span Model Support System

    NASA Technical Reports Server (NTRS)

    Jones, Greg S.; Milholen, William E., II; Goodliff, Scott L.

    2011-01-01

    The recent addition of a dual flow air delivery system to the NASA Langley National Transonic Facility was experimentally validated with a Dual Aerodynamic Nozzle semi-span model. This model utilized two Stratford calibration nozzles to characterize the weight flow system of the air delivery system. The weight flow boundaries for the air delivery system were identified at mildly cryogenic conditions to be 0.1 to 23 lbm/sec for the high flow leg and 0.1 to 9 lbm/sec for the low flow leg. Results from this test verified system performance and identified problems with the weight-flow metering system that required the vortex flow meters to be replaced at the end of the test.

  16. Comparison of Some Aspherical Curved Surfaces of A Single Biconcave Acoustic Lens System for Ambient Noise Imaging

    NASA Astrophysics Data System (ADS)

    Mori, K.; Ogasawara, H.; Nakamura, T.

    Ambient Noise Imaging (ANI) is a revolutionary method for detecting silent objects using the ocean's background noise. In this study, a sound field focused by an acoustic lens system constructed with a single biconcave lens was analyzed using the 2-D Finite Difference Time Domain (FDTD) method in order to design an ANI system. The -3dB areas and relative pressure level at image points were surveyed using lenses with some aspherical curved surfaces, such as popular aspherical lenses (elliptical, parabolic, and hyperbolic) and an aplanatic lens. The analysis results indicate that the effects of both spherical and coma aberrations were corrected by the aplanatic lens.

  17. Conceptual design study of a 5 kilowatt solar dynamic Brayton power system using a dome Fresnel lens solar concentrator

    NASA Technical Reports Server (NTRS)

    Oneill, Mark J.; Mcdanal, A. J.; Spears, Don H.

    1989-01-01

    The primary project objective was to generate a conceptual design for a nominal 5 kW solar dynamic space power system, which uses a unique, patented, transmittance-optimized, dome-shaped, point-focus Fresnel lens as the optical concentrator. Compared to reflective concentrators, the dome lens allows 200 times larger slope errors for the same image displacement. Additionally, the dome lens allows the energy receiver, the power conversion unit (PCU), and the heat rejection radiator to be independently optimized in configuration and orientation, since none of these elements causes any aperture blockage. Based on optical and thermal trade studies, a 6.6 m diameter lens with a focal length of 7.2 m was selected. This lens should provide 87 percent net optical efficienty at 800X geometric concentration ratio. The large lens is comprised of 24 gores, which compactly stow together during launch, and automatically deploy on orbit. The total mass of the microglass lens panels, the graphite/epoxy support structure, and miscellaneous hardware is about 1.2 kg per square meter of aperture. The key problem for the dome lens approach relates to the selection of a space-durable lens material. For the first time, all-glass Fresnel lens samples were successfully made by a sol-gel casting process.

  18. The Total In-Flight Simulator (TIFS) aerodynamics and systems: Description and analysis. [maneuver control and gust alleviators

    NASA Technical Reports Server (NTRS)

    Andrisani, D., II; Daughaday, H.; Dittenhauser, J.; Rynaski, E.

    1978-01-01

    The aerodynamics, control system, instrumentation complement and recording system of the USAF Total In/Flight Simulator (TIFS) airplane are described. A control system that would allow the ailerons to be operated collectively, as well as, differentially to entrance the ability of the vehicle to perform the dual function of maneuver load control and gust alleviation is emphasized. Mathematical prediction of the rigid body and the flexible equations of longitudinal motion using the level 2.01 FLEXSTAB program are included along with a definition of the vehicle geometry, the mass and stiffness distribution, the calculated mode frequencies and mode shapes, and the resulting aerodynamic equations of motion of the flexible vehicle. A complete description of the control and instrumentation system of the aircraft is presented, including analysis, ground test and flight data comparisons of the performance and bandwidth of the aerodynamic surface servos. Proposed modification for improved performance of the servos are also presented.

  19. HST observations of the gravitational lens systems HE 1104-1805 and J03.13

    NASA Technical Reports Server (NTRS)

    Remy, M.; Claeskens, J. F.; Surdej, J.

    1997-01-01

    High angular resolution Principle Component Image (PC1) images of the gravitational lens systems HE 1104-1805 and J03.13 are presented. Using a method described in Remy et al. (1997a), optimal TinyTim Point Spread Function (PSFs) are constructed to fit at best the lensed point-like components. The derived photometry of the GL components and the detection of the lens galaxy for HE 1104-1805 are discussed. Textbook case Faint Object Spectrograph (FOS) spectra of J03.13 A and B clearly show that this double QSO is a cosmic mirage.

  20. Dynamical systems analysis of electrostatic and aerodynamic forced vibrations of a thin flexible electrode

    NASA Astrophysics Data System (ADS)

    Madanu, Sushma Bala

    Transverse vibrations of an electrostatically actuated thin flexible cantilever perturbed by low-speed air flow is studied using both experiments and numerical modeling. In the experiments the dynamic characteristics of the cantilever are studied by supplying a DC voltage with an AC component for electrostatic forcing and a constant uniform air flow around the cantilever system for aerodynamic forcing. The maximum voltage applied varies from 1 - 9 kV and air flow speeds range from 0.224 - 3.58 m/s (0.5 - 8 mile/hr). The Reynolds numbers for these speeds lie in the range of 1000 - 20000. A range of control parameters leading to stable vibrations are established using the Strouhal number as the operating parameter whose inverse values change from 100 - 2500. The Numerical results are validated with experimental results. Assuming the amplitude of vibrations are small, then a non-linear dynamic Euler-Bernoulli beam equation with viscous damping and gravitational effects is used to model the vibrations of the dynamical system. Aerodynamic forcing is modeled as a temporally sinusoidal and uniform force acting perpendicular to the beam length. The forcing amplitude is found to be proportional to square of air flow velocity by obtaining relationship between the experimental amplitude of vibrations and air flow velocity. Numerical results strongly agree with those of experiments predicting accurate vibration amplitudes, displacement frequency and quasi-periodic displacements of the cantilever tip.

  1. Aerodynamic performance of a full-scale lifting ejector system in a STOVL fighter aircraft

    NASA Technical Reports Server (NTRS)

    Smith, Brian E.; Garland, Doug; Poppen, William A.

    1992-01-01

    The aerodynamic characteristics of an advanced lifting ejector system incorporated into a full-scale, powered, fighter aircraft model were measured at statically and at transition airspeeds in the 40- by 80- and 80- by 120-Foot Wind Tunnels at NASA-Ames. The ejector system was installed in an ejector-lift/vectored thrust STOVL (Short Take-Off Vertical Landing) fighter aircraft configuration. Ejector thrust augmentation ratios approaching 1.6 were demonstrated during static testing. Changes in the internal aerodynamics and exit flow conditions of the ejector ducts are presented for a variety of wind-off and forward-flight test conditions. Wind-on test results indicate a small decrease in ejector performance and increase in exit flow nonuniformity with forward speed. Simulated ejector start-up at high speed, nose-up attitudes caused only small effects on overall vehicle forces and moments despite the fact that the ejector inlet flow was found to induce large regions of negative pressure on the upper surface of the wing apex adjacent to the inlets.

  2. Aerodynamics of the advanced launch system (ALS) propulsion and avionics (P/A) module

    NASA Technical Reports Server (NTRS)

    Ferguson, Stan; Savage, Dick

    1992-01-01

    This paper discusses the design and testing of candidate Advanced Launch System (ALS) Propulsion and Avionics (P/A) Module configurations. The P/A Module is a key element of future launch systems because it is essential to the recovery and reuse of high-value propulsion and avionics hardware. The ALS approach involves landing of first stage (booster) and/or second stage (core) P/A modules near the launch site to minimize logistics and refurbishment cost. The key issue addressed herein is the aerodynamic design of the P/A module, including the stability characteristics and the lift-to-drag (L/D) performance required to achieve the necessary landing guidance accuracy. The reference P/A module configuration was found to be statically stable for the desired flight regime, to provide adequate L/D for targeting, and to have effective modulation of the L/D performance using a body flap. The hypersonic aerodynamic trends for nose corner radius, boattail angle and body flap deflections were consistent with pretest predictions. However, the levels for the L/D and axial force for hypersonic Mach numbers were overpredicted by impact theories.

  3. Student Satisfaction with Learning Management Systems: A Lens of Critical Success Factors

    ERIC Educational Resources Information Center

    Naveh, Gali; Tubin, Dorit; Pliskin, Nava

    2012-01-01

    Institutions of higher education have invested heavily in learning management systems (LMS) for creating course websites. Yet, how to assess LMS effectiveness is not fully agreed upon. Based on institutional theory, this article considers student satisfaction as indicative of LMS success and proposes a lens of critical success factors (CSF) as a…

  4. Auto-measurement system of aerial camera lens' resolution based on orthogonal linear CCD

    NASA Astrophysics Data System (ADS)

    Zhao, Yu-liang; Zhang, Yu-ye; Ding, Hong-yi

    2010-10-01

    The resolution of aerial camera lens is one of the most important camera's performance indexes. The measurement and calibration of resolution are important test items in in maintenance of camera. The traditional method that is observing resolution panel of collimator rely on human's eyes using microscope and doing some computing. The method is of low efficiency and susceptible to artificial factors. The measurement results are unstable, too. An auto-measurement system of aerial camera lens' resolution, which uses orthogonal linear CCD sensor as the detector to replace reading microscope, is introduced. The system can measure automatically and show result real-timely. In order to measure the smallest diameter of resolution panel which could be identified, two orthogonal linear CCD is laid on the imaging plane of measured lens and four intersection points are formed on the orthogonal linear CCD. A coordinate system is determined by origin point of the linear CCD. And a circle is determined by four intersection points. In order to obtain the circle's radius, firstly, the image of resolution panel is transformed to pulse width of electric signal which is send to computer through amplifying circuit and threshold comparator and counter. Secondly, the smallest circle would be extracted to do measurement. The circle extraction made using of wavelet transform which has character of localization in the domain of time and frequency and has capability of multi-scale analysis. Lastly, according to the solution formula of lens' resolution, we could obtain the resolution of measured lens. The measuring precision on practical measurement is analyzed, and the result indicated that the precision will be improved when using linear CCD instead of reading microscope. Moreover, the improvement of system error is determined by the pixel's size of CCD. With the technique of CCD developed, the pixel's size will smaller, the system error will be reduced greatly too. So the auto

  5. 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.

  6. Aerodynamic potpourri

    NASA Technical Reports Server (NTRS)

    Wilson, R. E.

    1981-01-01

    Aerodynamic developments for vertical axis and horizontal axis wind turbines are given that relate to the performance and aerodynamic loading of these machines. Included are: (1) a fixed wake aerodynamic model of the Darrieus vertical axis wind turbine; (2) experimental results that suggest the existence of a laminar flow Darrieus vertical axis turbine; (3) a simple aerodynamic model for the turbulent windmill/vortex ring state of horizontal axis rotors; and (4) a yawing moment of a rigid hub horizontal axis wind turbine that is related to blade coning.

  7. Aerodynamic potpourri

    NASA Astrophysics Data System (ADS)

    Wilson, R. E.

    1981-05-01

    Aerodynamic developments for vertical axis and horizontal axis wind turbines are given that relate to the performance and aerodynamic loading of these machines. Included are: (1) a fixed wake aerodynamic model of the Darrieus vertical axis wind turbine; (2) experimental results that suggest the existence of a laminar flow Darrieus vertical axis turbine; (3) a simple aerodynamic model for the turbulent windmill/vortex ring state of horizontal axis rotors; and (4) a yawing moment of a rigid hub horizontal axis wind turbine that is related to blade coning.

  8. An unstructured-grid software system for solving complex aerodynamic problems

    NASA Technical Reports Server (NTRS)

    Frink, Neal T.; Pirzadeh, Shahyar; Parikh, Paresh

    1995-01-01

    A coordinated effort has been underway over the past four years to elevate unstructured-grid methodology to a mature level. The goal of this endeavor is to provide a validated capability to non-expert users for performing rapid aerodynamic analysis and design of complex configurations. The Euler component of the system is well developed, and is impacting a broad spectrum of engineering needs with capabilities such as rapid grid generation and inviscid flow analysis, inverse design, interactive boundary layers, and propulsion effects. Progress is also being made in the more tenuous Navier-Stokes component of the system. A robust grid generator is under development for constructing quality thin-layer tetrahedral grids, along with a companion Navier-Stokes flow solver. This paper presents an overview of this effort, along with a perspective on the present and future status of the methodology.

  9. Design study for a 16x zoom lens system for visible surveillance camera

    NASA Astrophysics Data System (ADS)

    Vella, Anthony; Li, Heng; Zhao, Yang; Trumper, Isaac; Gandara-Montano, Gustavo A.; Xu, Di; Nikolov, Daniel K.; Chen, Changchen; Brown, Nicolas S.; Guevara-Torres, Andres; Jung, Hae Won; Reimers, Jacob; Bentley, Julie

    2015-09-01

    *avella@ur.rochester.edu Design study for a 16x zoom lens system for visible surveillance camera Anthony Vella*, Heng Li, Yang Zhao, Isaac Trumper, Gustavo A. Gandara-Montano, Di Xu, Daniel K. Nikolov, Changchen Chen, Nicolas S. Brown, Andres Guevara-Torres, Hae Won Jung, Jacob Reimers, Julie Bentley The Institute of Optics, University of Rochester, Wilmot Building, 275 Hutchison Rd, Rochester, NY, USA 14627-0186 ABSTRACT High zoom ratio zoom lenses have extensive applications in broadcasting, cinema, and surveillance. Here, we present a design study on a 16x zoom lens with 4 groups (including two internal moving groups), designed for, but not limited to, a visible spectrum surveillance camera. Fifteen different solutions were discovered with nearly diffraction limited performance, using PNPX or PNNP design forms with the stop located in either the third or fourth group. Some interesting patterns and trends in the summarized results include the following: (a) in designs with such a large zoom ratio, the potential of locating the aperture stop in the front half of the system is limited, with ray height variations through zoom necessitating a very large lens diameter; (b) in many cases, the lens zoom motion has significant freedom to vary due to near zero total power in the middle two groups; and (c) we discuss the trade-offs between zoom configuration, stop location, packaging factors, and zoom group aberration sensitivity.

  10. Toward a Wirelessly Powered On-Lens Intraocular Pressure Monitoring System.

    PubMed

    Chiou, Jin-Chern; Hsu, Shun-Hsi; Liao, Yu-Te; Huang, Yu-Chieh; Yeh, Guan-Ting; Kuei, Cheng-Kai; Dai, Kai-Shiun

    2016-09-01

    This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 μm thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-μW power. The on-lens capacitive sensor could detect dielectric variation caused by changes in water content from a distance of 2 cm by using incident power from an RFID reader at 20 dBm. The maximum detectable distance was 11 cm with 30-dBm incident RF power. The rise in eye tissue temperature under 30-dBm RF exposure over an interval of 1 s was simulated and found to be less than 0.01°C.

  11. Optical Systems Design With Reference To The Evolution Of The Double Gauss Lens

    NASA Astrophysics Data System (ADS)

    Woltche, Walter

    1980-09-01

    This year 140 years have elapsed since the first photographic objective was designed, more than 90 years have passed since the first anastigmatic lenses were created and about 20 years ago computer-aided lens design was started. The double Gauss lens will be used as an example to outline the problems, procedures and results obtained in designing optical systems. In retrospect a search will be made for the first introduction and development of the double Gauss lens in order to draw further conclusions from the historical facts as to the ideas that have led to the present state of the art. Contemporary systems of the double Gauss lens will be demonstrated with regard to the available construction parameters and the numerous fields of application. While discussing several variants emphasis will be placed on the choice of glass types for high speed lenses, the relationship between refractive index and image quality and the comparison between performance and costs. Recent explorations led to double Gauss lenses with special properties. New objectives with stabilized performance, ultra high speed lenses and lenses with reduced secondary spectrum will be presented.

  12. Toward a Wirelessly Powered On-Lens Intraocular Pressure Monitoring System.

    PubMed

    Chiou, Jin-Chern; Hsu, Shun-Hsi; Liao, Yu-Te; Huang, Yu-Chieh; Yeh, Guan-Ting; Kuei, Cheng-Kai; Dai, Kai-Shiun

    2016-09-01

    This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 μm thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-μW power. The on-lens capacitive sensor could detect dielectric variation caused by changes in water content from a distance of 2 cm by using incident power from an RFID reader at 20 dBm. The maximum detectable distance was 11 cm with 30-dBm incident RF power. The rise in eye tissue temperature under 30-dBm RF exposure over an interval of 1 s was simulated and found to be less than 0.01°C. PMID:27479980

  13. 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.

  14. Multitarget tracking system based on an infrared fish-eye lens.

    PubMed

    Li, Gang; Li, Li; Shen, Hongbin; He, Yongqiang; Huang, Jingxia; Mao, Shaojuan; Wang, Yuanbo

    2013-11-20

    A multitarget tracking system based on an infrared (IR) fish-eye lens is built to satisfy urgent requirements of large-field IR, multitarget, real-time reconnaissance and tracking. Utilizing an IR fish-eye lens and a 512×512 pixel PtSi detector, the system can detect threatening targets at the whole space domain and the whole time domain. The hardware of the system based on a dual-digital signal processor is designed to implement data processing for multitarget tracking algorithms, which include a track initiation algorithm and a modified generalized probability data association algorithm. We also carried out a tracking experiment for two aerial maneuvering targets. Comparing the theoretical and experimental tracks, the availability of the system and the real-time capability of multitarget tracking are validated.

  15. Nonlinear Predictive Control of Wind Energy Conversion System Using Dfig with Aerodynamic Torque Observer

    NASA Astrophysics Data System (ADS)

    Kamel, Ouari; Mohand, Ouhrouche; Toufik, Rekioua; Taib, Nabil

    2015-01-01

    In order to improvement of the performances for wind energy conversions systems (WECS), an advanced control techniques must be used. In this paper, as an alternative to conventional PI-type control methods, a nonlinear predictive control (NPC) approach is developed for DFIG-based wind turbine. To enhance the robustness of the controller, a disturbance observer is designed to estimate the aerodynamic torque which is considered as an unknown perturbation. An explicitly analytical form of the optimal predictive controller is given consequently on-line optimization is not necessary The DFIG is fed through the rotor windings by a back-to-back converter controlled by Pulse Width Modulation (PWM), where the stator winding is directly connected to the grid. The presented simulation results show a good performance in trajectory tracking of the proposed strategy and rejection of disturbances is successfully achieved.

  16. On the Use of Parmetric-CAD Systems and Cartesian Methods for Aerodynamic Design

    NASA Technical Reports Server (NTRS)

    Nemec, Marian; Aftosmis, Michael J.; Pulliam, Thomas H.

    2004-01-01

    Automated, high-fidelity tools for aerodynamic design face critical issues in attempting to optimize real-life geometry arid in permitting radical design changes. Success in these areas promises not only significantly shorter design- cycle times, but also superior and unconventional designs. To address these issues, we investigate the use of a parmetric-CAD system in conjunction with an embedded-boundary Cartesian method. Our goal is to combine the modeling capabilities of feature-based CAD with the robustness and flexibility of component-based Cartesian volume-mesh generation for complex geometry problems. We present the development of an automated optimization frame-work with a focus on the deployment of such a CAD-based design approach in a heterogeneous parallel computing environment.

  17. Systems Thinking: A Lens and Scalpel for Organizational Learning.

    ERIC Educational Resources Information Center

    Galbraith, Peter

    This paper examines the role of systems thinking in higher education, explaining that university examples provide a sense of what systems thinking entails when applied within large, complex organizations. It shares insights provided by the system dynamics approach for approaches to organizational leadership in education. A system dynamics approach…

  18. Potential impacts of advanced aerodynamic technology on air transportation system productivity

    NASA Technical Reports Server (NTRS)

    Bushnell, Dennis M. (Editor)

    1994-01-01

    Summaries of a workshop held at NASA Langley Research Center in 1993 to explore the application of advanced aerodynamics to airport productivity improvement are discussed. Sessions included discussions of terminal area productivity problems and advanced aerodynamic technologies for enhanced high lift and reduced noise, emissions, and wake vortex hazard with emphasis upon advanced aircraft configurations and multidisciplinary solution options.

  19. An Aeroelastic Evaluation of the Flexible Thermal Protection System for an Inatable Aerodynamic Decelerator

    NASA Astrophysics Data System (ADS)

    Goldman, Benjamin D.

    The purpose of this dissertation is to study the aeroelastic stability of a proposed flexible thermal protection system (FTPS) for the NASA Hypersonic Inflatable Aerodynamic Decelerator (HIAD). A flat, square FTPS coupon exhibits violent oscillations during experimental aerothermal testing in NASA's 8 Foot High Temperature Tunnel, leading to catastrophic failure. The behavior of the structural response suggested that aeroelastic flutter may be the primary instability mechanism, prompting further experimental investigation and theoretical model development. Using Von Karman's plate theory for the panel-like structure and piston theory aerodynamics, a set of aeroelastic models were developed and limit cycle oscillations (LCOs) were calculated at the tunnel flow conditions. Similarities in frequency content of the theoretical and experimental responses indicated that the observed FTPS oscillations were likely aeroelastic in nature, specifically LCO/flutter. While the coupon models can be used for comparison with tunnel tests, they cannot predict accurately the aeroelastic behavior of the FTPS in atmospheric flight. This is because the geometry of the flight vehicle is no longer a flat plate, but rather (approximately) a conical shell. In the second phase of this work, linearized Donnell conical shell theory and piston theory aerodynamics are used to calculate natural modes of vibration and flutter dynamic pressures for various structural models composed of one or more conical shells resting on several circumferential elastic supports. When the flight vehicle is approximated as a single conical shell without elastic supports, asymmetric flutter in many circumferential waves is observed. When the elastic supports are included, the shell flutters symmetrically in zero circumferential waves. Structural damping is found to be important in this case, as "hump-mode" flutter is possible. Aeroelastic models that consider the individual FTPS layers as separate shells exhibit

  20. Multimodal 3-D reconstruction of human anatomical structures using SurLens Visualization System.

    PubMed

    Adeshina, A M; Hashim, R; Khalid, N E A; Abidin, S Z Z

    2013-03-01

    In the medical diagnosis and treatment planning, radiologists and surgeons rely heavily on the slices produced by medical imaging devices. Unfortunately, these image scanners could only present the 3-D human anatomical structure in 2-D. Traditionally, this requires medical professional concerned to study and analyze the 2-D images based on their expert experience. This is tedious, time consuming and prone to error; expecially when certain features are occluding the desired region of interest. Reconstruction procedures was earlier proposed to handle such situation. However, 3-D reconstruction system requires high performance computation and longer processing time. Integrating efficient reconstruction system into clinical procedures involves high resulting cost. Previously, brain's blood vessels reconstruction with MRA was achieved using SurLens Visualization System. However, adapting such system to other image modalities, applicable to the entire human anatomical structures, would be a meaningful contribution towards achieving a resourceful system for medical diagnosis and disease therapy. This paper attempts to adapt SurLens to possible visualisation of abnormalities in human anatomical structures using CT and MR images. The study was evaluated with brain MR images from the department of Surgery, University of North Carolina, United States and CT abdominal pelvic, from the Swedish National Infrastructure for Computing. The MR images contain around 109 datasets each of T1-FLASH, T2-Weighted, DTI and T1-MPRAGE. Significantly, visualization of human anatomical structure was achieved without prior segmentation. SurLens was adapted to visualize and display abnormalities, such as an indication of walderstrom's macroglobulinemia, stroke and penetrating brain injury in the human brain using Magentic Resonance (MR) images. Moreover, possible abnormalities in abdominal pelvic was also visualized using Computed Tomography (CT) slices. The study shows SurLens' functionality as

  1. Systems Thinking: A New Lens for Old Problems

    ERIC Educational Resources Information Center

    Bierema, Laura L.

    2003-01-01

    This article introduces systems thinking and identifies its implications for practice-based learning and improvement. The article defines systems, identifies fundamental aspects of systems thinking, and provides strategies for creating more practice-based learning environments in medical contexts. (Contains 1 table.)

  2. Modal liquid crystal lens driven by low voltage produced from a wireless controlling and driving system

    NASA Astrophysics Data System (ADS)

    Zhang, Xinyu; Loktev, Mikhail; Vdovin, Gleb

    2005-04-01

    A wireless driving and controlling setup constructed by a coil system and a simple power metal-oxide-semiconductor field effect transistor switch circuit for modal liquid crystal lens has been designed, fabricated and characterized. Electrical and structural modeling and analysis have been applied to the design of the wireless power transforming and controlling system. Some key electrical characteristics of coils with different diameter and winding, such as resistance, impedance, capacitance, inductance, and Q factor, which determine the driving and controlling behaviors of the coil system constructed, are given. The liquid crystal lens can be operated under relatively low driving voltage ranging from about 1.5to12Vrms. Under dynamic operation, the prototype system has shown a stable driving and controlling performance to liquid crystal lens under the condition of switching mode of a few KHz. The possibility of integrating very small coils connected in series onto a small-size silicon chip as an integrated receiver in biomedicine application has been shown experimentally.

  3. Novel compact panomorph lens based vision system for monitoring around a vehicle

    NASA Astrophysics Data System (ADS)

    Thibault, Simon

    2008-04-01

    Automotive applications are one of the largest vision-sensor market segments and one of the fastest growing ones. The trend to use increasingly more sensors in cars is driven both by legislation and consumer demands for higher safety and better driving experiences. Awareness of what directly surrounds a vehicle affects safe driving and manoeuvring of a vehicle. Consequently, panoramic 360° Field of View imaging can contributes most to the perception of the world around the driver than any other sensors. However, to obtain a complete vision around the car, several sensor systems are necessary. To solve this issue, a customized imaging system based on a panomorph lens will provide the maximum information for the drivers with a reduced number of sensors. A panomorph lens is a hemispheric wide angle anamorphic lens with enhanced resolution in predefined zone of interest. Because panomorph lenses are optimized to a custom angle-to-pixel relationship, vision systems provide ideal image coverage that reduces and optimizes the processing. We present various scenarios which may benefit from the use of a custom panoramic sensor. We also discuss the technical requirements of such vision system. Finally we demonstrate how the panomorph based visual sensor is probably one of the most promising ways to fuse many sensors in one. For example, a single panoramic sensor on the front of a vehicle could provide all necessary information for assistance in crash avoidance, lane tracking, early warning, park aids, road sign detection, and various video monitoring views.

  4. Light field and crosshair quality assurance test using a simple lens system

    SciTech Connect

    Hadley, Scott W.; Lam, Kwok

    2006-04-15

    We describe here a simple lens system to test the positioning of the field light source and mylar crosshair for radiation therapy linear accelerators. Ideally the light source for the field light and the crosshair should be centered on the axis of rotation of the collimator. The traditional method for testing this coincidence uses the shadow of the crosshair caused by the field light source. The shadow of the crosshair is dependent on the position of both the field light source and mylar crosshair. Geometrically it is possible for the field light source and the mylar crosshair to be off the axis of rotation of the collimator and still cause the shadow of the crosshair to be on the axis of rotation at some distance. Using a lens system the motion of the field light source and crosshair can be observed in sharp focus independently of one another as the collimator is rotated.

  5. Experimental demonstration of reduced tilt-to-length coupling by a two-lens imaging system.

    PubMed

    Schuster, Sönke; Tröbs, Michael; Wanner, Gudrun; Heinzel, Gerhard

    2016-05-16

    The coupling between beam tilt and longitudinal path length readout in a setup representing a LISA test mass interferometer was reduced to below 2 µm/rad using a two lens imaging system. This was achieved by the use of a homodyne equal arm-length Mach-Zehnder interferometer and suppression of the dominating effects of higher order Gaussian modes and longitudinal actuator movement. The latter was subtracted using the phase signal of a large single element photo diode. PMID:27409870

  6. Design and development of a laminated glass-plastic Fresnel lens for point focus photovoltaic systems

    SciTech Connect

    Matalon, L. A.

    1982-08-01

    The design and development of a laminated glass-plastic Fresnel lens for point focus photovoltaic systems use is described. The objective of this development was to examine the feasibility of producing lenses with a cost effectiveness superior to that of lenses made by casting of acrylic. The procedure used in executing this development, the method used in cost effectiveness evaluation, results obtained and recommendations for further work are presented.

  7. Aerodynamic heating environment definition/thermal protection system selection for the HL-20

    NASA Technical Reports Server (NTRS)

    Wurster, K. E.; Stone, H. W.

    1993-01-01

    Definition of the aerothermal environment is critical to any vehicle such as the HL-20 Personnel Launch System that operates within the hypersonic flight regime. Selection of an appropriate thermal protection system design is highly dependent on the accuracy of the heating-environment prediction. It is demonstrated that the entry environment determines the thermal protection system design for this vehicle. The methods used to predict the thermal environment for the HL-20 Personnel Launch System vehicle are described. Comparisons of the engineering solutions with computational fluid dynamic predictions, as well as wind-tunnel test results, show good agreement. The aeroheating predictions over several critical regions of the vehicle, including the stagnation areas of the nose and leading edges, windward centerline and wing surfaces, and leeward surfaces, are discussed. Results of predictions based on the engineering methods found within the MINIVER aerodynamic heating code are used in conjunction with the results of the extensive wind-tunnel tests on this configuration to define a flight thermal environment. Finally, the selection of the thermal protection system based on these predictions and current technology is described.

  8. Deep Tissue Microscopic Imaging of the Kidney with a Gradient-Index Lens System

    PubMed Central

    Li, Xin; Yu, Weiming

    2008-01-01

    Intravital microscopy using two-photon excitation is proven to be a valuable tool for studying the kidney and associated disease processes. However, routine performance of intravital kidney imaging is limited by the fact that fluorescence signal is attenuated by the tissue and at certain tissue depth lost its strength completely. For most of the animal tissues, this finite imaging depth is limited to a few hundred microns. Currently it is not possible to non-invasively image the kidney beyond the superficial tissue layers of the cortex. This has imposed significant limitations on the animal models one can use for imaging since structure such the glomerulus is typically located below the superficial layer of the cortex that can not be imaged using a conventional fluorescence microscope. Here we report the use of a needle-like lens system based on gradient-index (GRIN) microlenses capable of transferring high quality fluorescence images of the tissue through a regular microscope objective for deep tissue imaging of the kidney. By combining this GRIN lens system with a Zeiss LSM 510 NLO microscope, we are able to extend the imaging depth for kidney tissues far beyond the few hundred microns limit. This GRIN lens imaging system provides an alternative microendoscopic imaging tool that will enhance current intravital kidney imaging techniques for studying structural and functional properties of local tissues at locations below the superficial layers of the kidney. PMID:19572038

  9. Deep Tissue Microscopic Imaging of the Kidney with a Gradient-Index Lens System.

    PubMed

    Li, Xin; Yu, Weiming

    2008-04-01

    Intravital microscopy using two-photon excitation is proven to be a valuable tool for studying the kidney and associated disease processes. However, routine performance of intravital kidney imaging is limited by the fact that fluorescence signal is attenuated by the tissue and at certain tissue depth lost its strength completely. For most of the animal tissues, this finite imaging depth is limited to a few hundred microns. Currently it is not possible to non-invasively image the kidney beyond the superficial tissue layers of the cortex. This has imposed significant limitations on the animal models one can use for imaging since structure such the glomerulus is typically located below the superficial layer of the cortex that can not be imaged using a conventional fluorescence microscope. Here we report the use of a needle-like lens system based on gradient-index (GRIN) microlenses capable of transferring high quality fluorescence images of the tissue through a regular microscope objective for deep tissue imaging of the kidney. By combining this GRIN lens system with a Zeiss LSM 510 NLO microscope, we are able to extend the imaging depth for kidney tissues far beyond the few hundred microns limit. This GRIN lens imaging system provides an alternative microendoscopic imaging tool that will enhance current intravital kidney imaging techniques for studying structural and functional properties of local tissues at locations below the superficial layers of the kidney.

  10. The light-curve reconstruction method for measuring the time delay of gravitational lens systems

    NASA Astrophysics Data System (ADS)

    Geiger, Bernhard; Schneider, Peter

    1996-09-01

    We propose a new technique for measuring the time delay of radio-loud gravitational lens systems, which does not rely on the excessive use of interferometric observations. Instead, the method is based on single-dish flux density monitoring of the total light curve of the (unresolved) lens system, combined with additional interferometric measurements of the flux density ratio at a few epochs during that monitoring period. The basic idea of the method is to reconstruct the individual image light curves from the observed total light curve by assuming a range of potential values for the time delay and the magnification ratio of the images. It is then possible to single out the correct reconstruction, and therefore determine the time delay, by checking the consistency of the reconstructed individual light curves with the additional interferometric observations. We performed extensive numerical simulations of synthetic light curves to investigate the dependence of the performance of this method on various parameters which are involved in the problem. Probably the most promising candidates for applying the method (and also for determining the Hubble constant) are lens systems consisting of multiply imaged compact sources and an Einstein ring, such as B 0218+357 from which some of the parameters used for our simulations were adopted.

  11. Investigation of uniformity field generated from freeform lens with UV LED exposure system

    NASA Astrophysics Data System (ADS)

    Ciou, F. Y.; Chen, Y. C.; Pan, C. T.; Lin, P. H.; Lin, P. H.; Hsu, F. T.

    2015-03-01

    In the exposure process, the intensity and uniformity of light in the exposure area directly influenced the precision of products. UV-LED (Ultraviolet Light-Emitting Diode) exposure system was established to reduce the radiation leakage and increase the energy efficiency for energy saving. It is a trend that conventional mercury lamp could be replaced with UV-LED exposure system. This study was based on the law of conservation of energy and law of refraction of optical field distributing on the target plane. With these, a freeform lens with uniform light field of main exposure area could be designed. The light outside the exposure area could be concentrated into the area to improve the intensity of light. The refraction index and UV transmittance of Polydimethylsiloxane (PDMS) is 1.43 at 385 nm wavelength and 85-90%, respectively. The PDMS was used to fabricate the optics lens for UV-LEDs. The average illumination and the uniformity could be obtained by increasing the number of UV-LEDs and the spacing of different arrangement modes. After exposure process with PDMS lens, about 5% inaccuracy was obtained. Comparing to 10% inaccuracy of general exposure system, it shows that it is available to replace conventional exposure lamp with using UV-LEDs.

  12. Optical system design for lens with large relative aperture

    NASA Astrophysics Data System (ADS)

    Zhang, Kaisheng; Zhang, Zhi; Zhang, Zhaohui; Wang, Zefeng; Yan, Aqi; Fei, Jiaqi; Mei, Chao; Zhang, Gaopeng

    2015-10-01

    As the space remote sensing technology progresses, the developing trend of telescope is larger and larger aperture, higher and higher resolution. An Optical system with the relative aperture of 1:2 is introduced. The primary optical properties are: focal length of 120mm, F number of 2, field angle of 7.4°. It has the advantages of large high resolution, small size and excellent image quality. Several kinds of aberration curves and the MTF curve are given. Its imaging quality is nearly diffraction limited so that the spatial frequency is greater than 70lp/mm when its modulated transfer function (MTF) value of the optical system is equal to 0.8,and the optical system distortion is less than 1%. At last, the stray light is analyzed and the baffle of the telescope is designed. The solid model of the Optical system was constructed in Tracepro software, the point sources transmittance (PST) cure was given at different off-axis angle between 7.4°~80° the analysis result indicates that the PST values are less than 10-6 when off-axis angle are larger than soar critical angle. So the system is suitable for observation or photography of deep sky objects.

  13. Design and development of a laminated Fresnel lens for point-focus PV systems. Phase II

    SciTech Connect

    Hodge, R.C.

    1982-12-01

    A laminated glass-plastic lens parquet using injection molded point focus Fresnel lenses is described. The second phase of a program aimed at investigating the cost effectiveness of a glass-plastic concentrator lens assembly is reported. The first phase dealt with the development of a first generation lens design, the selection of the preferred glass coverplate and glass-to-lens adhesive and initial injection molding lens molding trials. The second phase has dealt with the development of an improved lens design, a full size parquet lamination process, and a second group of injection molding lens molding trials.

  14. Evaluation of lens distortion errors using an underwater camera system for video-based motion analysis

    NASA Technical Reports Server (NTRS)

    Poliner, Jeffrey; Fletcher, Lauren; Klute, Glenn K.

    1994-01-01

    Video-based motion analysis systems are widely employed to study human movement, using computers to capture, store, process, and analyze video data. This data can be collected in any environment where cameras can be located. One of the NASA facilities where human performance research is conducted is the Weightless Environment Training Facility (WETF), a pool of water which simulates zero-gravity with neutral buoyance. Underwater video collection in the WETF poses some unique problems. This project evaluates the error caused by the lens distortion of the WETF cameras. A grid of points of known dimensions was constructed and videotaped using a video vault underwater system. Recorded images were played back on a VCR and a personal computer grabbed and stored the images on disk. These images were then digitized to give calculated coordinates for the grid points. Errors were calculated as the distance from the known coordinates of the points to the calculated coordinates. It was demonstrated that errors from lens distortion could be as high as 8 percent. By avoiding the outermost regions of a wide-angle lens, the error can be kept smaller.

  15. On the origin of the flux ratio anomaly in quadruple lens systems

    NASA Astrophysics Data System (ADS)

    Inoue, Kaiki Taro

    2016-09-01

    We explore the origin of the flux ratio anomaly in quadruple lens systems. Using a semi-analytic method based on N-body simulations, we estimate the effect of a possible magnification perturbation caused by subhaloes with a mass scale of ≲109 h-1 M⊙ in lensing galaxy haloes. Taking into account astrometric shifts and assuming that the primary lens is described by a singular isothermal ellipsoid, the expected change to the flux ratios for a multiply lensed image is just a few per cent and the mean of the expected convergence perturbation at the effective Einstein radius of the lensing galaxy halo is <δκsub> = 0.003, corresponding to the mean of the ratio of a projected dark matter mass fraction in subhaloes at the effective Einstein radius = 0.006. In contrast, the expected change to the flux ratio caused by line-of-sight structures is typically ˜10 per cent and the mean of the convergence perturbation is <|δκlos|> = 0.008, corresponding to = 0.017. The contribution of the magnification perturbation caused by subhaloes is ˜40 per cent of the total at a source redshift zS = 0.7 and decreases monotonically in zS to ˜20 per cent at zS = 3.6. Assuming statistical isotropy, the convergence perturbation estimated from 11 observed quadruple lens systems has a positive correlation with the source redshift zS, which is much stronger than that with the lens redshift zL. This feature also supports that the flux ratio anomaly is caused mainly by line-of-sight structures rather than subhaloes. We also discuss a possible imprint of line-of-sight structures in the demagnification of minimum images due to locally underdense structures in the line of sight.

  16. Study of the triple-mass Tethered Satellite System under aerodynamic drag and J2 perturbations

    NASA Astrophysics Data System (ADS)

    Razzaghi, Pourya; Assadian, Nima

    2015-11-01

    The dynamics of multi-tethered satellite formations consisting of three masses are studied in this paper. The triple-mass triple-tethered satellite system is modeled under the low Earth orbit perturbations of drag and Earth's oblateness and its equilibrium conditions are derived. It is modeled as three equal end-masses connected by a uniform-mass straight tether. The lengths of tethers are supposed to be constant and in this manner the angles of the plane consisting the masses are taken as the state variables of the system. The governing equations of motion are derived using Lagrangian approach. The aerodynamic drag perturbation is expressed as an external non-conservative force and the Earth oblateness (J2 perturbation) is considered as a term of potential energy. The equilibrium conditions of this system are found and their stability is investigated through the linear stability theory. Then, the results are verified by using a nonlinear simulation for three types of equilibrium conditions.

  17. Geometries and focal properties of two electron-lens systems useful in low-energy electron or ion scattering.

    PubMed

    Chutjian, A

    1979-03-01

    Geometries and focal properties are given for two types of electron-lens systems commonly needed in electron scattering. One is an electron gun which focuses electrons from a thermionic emitter onto a fixed point (target) over a wide range of final energies. The other is an electron analyzer system which focuses scattered electrons of variable energy onto a fixed position (e.g., the entrance plane of an analyzer) at fixed energy with a zero final beam angle. Analyzer-system focusing properties are given for superelastic, elastic, and inelastically-scattered electrons. Computer calculations using recent, accurate tube-lens focal properties are used to compute lens voltages, locations and diameters of all pupils and windows, and filling factors and asymptotic rays throughout each lens system. Focus voltages as a function of electron energy and energy change are given, and limits of operation of each system discussed. Both lens systems have been in routine use for several years, and good agreement has been consistently found between calculated and operating lens voltages.

  18. Model aerodynamic test results for two variable cycle engine coannular exhaust systems at simulated takeoff and cruise conditions. Comprehensive data report. Volume 2: Tabulated aerodynamic data book 2

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.

    1981-01-01

    Tabulated aerodynamic data from coannular nozzle performance tests are given for test runs 26 through 37. The data include nozzle thrust coefficient parameters, nozzle discharge coefficients, and static pressure tap measurements.

  19. Modeling aerodynamic discontinuities and the onset of chaos in flight dynamical systems

    NASA Technical Reports Server (NTRS)

    Tobak, M.; Chapman, G. T.; Uenal, A.

    1986-01-01

    Various representations of the aerodynamic contribution to the aircraft's equation of motion are shown to be compatible within the common assumption of their Frechet differentiability. Three forms of invalidating Frechet differentiality are identified, and the mathematical model is amended to accommodate their occurrence. Some of the ways in which chaotic behavior may emerge are discussed, first at the level of the aerodynamic contribution to the equation of motion, and then at the level of the equations of motion themselves.

  20. Effective method to improve the lens F# of un-cooled IR detector systems

    NASA Astrophysics Data System (ADS)

    Dong, Li-quan; Jin, Wei-qi; Sui, Jing; Zhou, Xiao-xiao

    2008-02-01

    The Infrared thermal imaging systems has developments advance rapidly during the development of the research and the manufacture technical. And its applied field has going deep into the astronautics, industry, agriculture, medical, traffic and other fields from the national defense and military appliance. Especially in the application of the military, it has come into being a specialty IR System Engineering field. But in many important applications, the lens calibre of the IR thermal imaging systems often be made very large to advance the SNR of the systems. This increased the weight and the research cost of the whole system very much. Many research indicated that the main factor to affect the image quality of the IR systems is the fixed pattern noise (FPN) or spatial non-uniformity under the actual technical and manufacture level. If we using the effective dynamic self-adaptive non-uniformity correction algorithms for the IR system, and use the image enhancement technology simultaneity. We can advance the imaging quality greatly. With this plan, the correction image we got with large F number can receive the level that uncorrected image with 1 or 2 smaller F number. It means the lens calibre of the system will be reduced effectively. And the weight, the cubage and the research cost of the system will be reduced greatly. It will have most important value in the applied of the actual engineering.

  1. A new lens for supporting and studying science teacher reflections: situating the self in the [activity] system

    NASA Astrophysics Data System (ADS)

    Criswell, Brett; Calandra, Brendan; Puvirajah, Anton; Brantley-Dias, Laurie

    2015-12-01

    This paper presents a new lens for analyzing written reflections on the teaching experiences of pre-service [science] teachers. The lens, which borrows heavily from Activity Theory, allows science education researchers and teacher educators to identify tensions, disturbances, conflicts, and contradictions within teachers' written reflections as a means to help the participants situate their successes and challenges within the activity systems in which they operate. This paper describes the process through which the lens was crafted, defines the key constructs comprising the lens, applies the lens to the analysis of two purposefully selected reflection documents, and then considers the affordances of the lens. It also discusses how the insights gained from this lens have lead to new ways of facilitating reflection in pre-service science teachers, including the use of Kenneth Snelson's tensegrity sculptures as a metaphor for the goal of reflection. Finally, it connects the tensions identified in the individual reflections of two pre-service science teachers to broader issues being addressed in science education.

  2. Handling and safety enhancement of race cars using active aerodynamic systems

    NASA Astrophysics Data System (ADS)

    Diba, Fereydoon; Barari, Ahmad; Esmailzadeh, Ebrahim

    2014-09-01

    A methodology is presented in this work that employs the active inverted wings to enhance the road holding by increasing the downward force on the tyres. In the proposed active system, the angles of attack of the vehicle's wings are adjusted by using a real-time controller to increase the road holding and hence improve the vehicle handling. The handling of the race car and safety of the driver are two important concerns in the design of race cars. The handling of a vehicle depends on the dynamic capabilities of the vehicle and also the pneumatic tyres' limitations. The vehicle side-slip angle, as a measure of the vehicle dynamic safety, should be narrowed into an acceptable range. This paper demonstrates that active inverted wings can provide noteworthy dynamic capabilities and enhance the safety features of race cars. Detailed analytical study and formulations of the race car nonlinear model with the airfoils are presented. Computer simulations are carried out to evaluate the performance of the proposed active aerodynamic system.

  3. Investigation of Aerodynamic and Icing Characteristics of a Flush Alternate Inlet Induction System Air Scoop

    NASA Technical Reports Server (NTRS)

    Lewis, James P.

    1953-01-01

    An investigation has been made in the NACA Lewis icing research tunnel to determine the aerodynamic and icing characteristics of a full-scale induction-system air-scoop assembly incorporating a flush alternate inlet. The flush inlet was located immediately downstream of the offset ram inlet and included a 180 deg reversal and a 90 deg elbow in the ducting between inlet and carburetor top deck. The model also had a preheat-air inlet. The investigation was made over a range of mass-air- flow ratios of 0 to 0.8, angles of attack of 0 and 4 deg airspeeds of 150 to 270 miles per hour, air temperatures of 0 and 25 F various liquid-water contents, and droplet sizes. The ram inlet gave good pressure recovery in both clear air and icing but rapid blockage of the top-deck screen occurred during icing. The flush alternate inlet had poor pressure recovery in both clear air and icing. The greatest decreases in the alternate-inlet pressure recovery were obtained at icing conditions of low air temperature and high liquid-water content. No serious screen icing was observed with the alternate inlet. Pressure and temperature distributions on the carburetor top deck were determined using the preheat-air supply with the preheat- and alternate-inlet doors in various positions. No screen icing occurred when the preheat-air system was operated in combination with alternate-inlet air flow.

  4. Using a commercial CAD system for simultaneous input to theoretical aerodynamic programs and wind-tunnel model construction

    NASA Technical Reports Server (NTRS)

    Enomoto, F.; Keller, P.

    1984-01-01

    The Computer Aided Design (CAD) system's common geometry database was used to generate input for theoretical programs and numerically controlled (NC) tool paths for wind tunnel part fabrication. This eliminates the duplication of work in generating separate geometry databases for each type of analysis. Another advantage is that it reduces the uncertainty due to geometric differences when comparing theoretical aerodynamic data with wind tunnel data. The system was adapted to aerodynamic research by developing programs written in Design Analysis Language (DAL). These programs reduced the amount of time required to construct complex geometries and to generate input for theoretical programs. Certain shortcomings of the Design, Drafting, and Manufacturing (DDM) software limited the effectiveness of these programs and some of the Calma NC software. The complexity of aircraft configurations suggests that more types of surface and curve geometry should be added to the system. Some of these shortcomings may be eliminated as improved versions of DDM are made available.

  5. Aerodynamic coefficients and transformation tables

    NASA Technical Reports Server (NTRS)

    Ames, Joseph S

    1918-01-01

    The problem of the transformation of numerical values expressed in one system of units into another set or system of units frequently arises in connection with aerodynamic problems. Report contains aerodynamic coefficients and conversion tables needed to facilitate such transformation. (author)

  6. Test, Evaluation, and Demonstration of Practical Devices/Systems to Reduce Aerodynamic Drag of Tractor/Semitrailer Combination Unit Trucks

    SciTech Connect

    Scott Smith; Karla Younessi; Matt Markstaller; Dan Schlesinger; Bhaskar Bhatnagar; Donald Smith; Bruno Banceu; Ron Schoon; V.K. Sharma; Mark Kachmarsky; Srikant Ghantae; Michael Sorrels; Conal Deedy; Justin Clark; Skip Yeakel; Michael D. Laughlin; Charlotte Seigler; Sidney Diamond

    2007-04-30

    Class 8 heavy-duty trucks account for over three-quarters of the total diesel fuel used by commercial trucks (trucks with GVWRs more than 10,000 pounds) in the United States each year. At the highway speeds at which these trucks travel (i.e., 60 mph or greater), aerodynamic drag is a major part of total horsepower needed to move the truck down the highway, Reductions in aerodynamic drag can yield measurable benefits in fuel economy through the use of relatively inexpensive and simple devices. The goal of this project was to examine a number of aerodynamic drag reduction devices and systems and determine their effectiveness in reducing aerodynamic drag of Class 8 tractor/semitrailer combination-units, thus contributing to DOE's goal of reducing transportation petroleum use. The project team included major heavy truck manufacturers in the United States, along with the management and industry expertise of the Truck Manufacturers Association as the lead investigative organization. The Truck Manufacturers Association (TMA) is the national trade association representing the major North American manufacturers of Class 6-8 trucks (GVWRs over 19,500 lbs). Four major truck manufacturers participated in this project with TMA: Freightliner LLC; International Truck and Engine Corporation; Mack Trucks Inc.; and Volvo Trucks North America, Inc. Together, these manufacturers represent over three-quarters of total Class 8 truck sales in the United States. These four manufacturers pursued complementary research efforts as part of this project. The project work was separated into two phases conducted over a two-year period. In Phase I, candidate aerodynamic devices and systems were screened to focus research and development attention on devices that offered the most potential. This was accomplished using full-size vehicle tests, scale model tests, and computational fluid dynamics analyses. In Phase II, the most promising devices were installed on full-size trucks and their effect on

  7. An aerodynamic analysis computer program and design notes for low speed wing flap systems

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Walkley, K. B.

    1983-01-01

    The expanded capabilities for analysis and design of low speed flap systems afforded by recent modifications of an existing computer program is described. The program provides for the simultaneous analysis of up to 25 pairs of leading-edge and trailing-edge flap deflection schedules. Among other new features of the program are a revised attainable thrust estimation method to provide more accurate predictions for low Mach numbers, and a choice of three options for estimation of leading-edge separation vortex flow effects. Comparison of program results with low speed experimental data for an arrow wing supersonic cruise configuration with leading-edge and trailing-edge flaps showed good agreement over most of the range of flap deflections. Other force data comparisons and an independent study of airfoil and wing pressure distributions indicated that wind-tunnel measurements of the aerodynamic performance of twisted and cambered wings and wings with leading-edge flaps can be very sensitive to Reynolds number effects.

  8. System ID modern control algorithms for active aerodynamic load control and impact on gearbox loading.

    SciTech Connect

    Berg, Jonathan Charles; Halse, Chris; Crowther, Ashley; Barlas, Thanasis; Wilson, David Gerald; Berg, Dale E.; Resor, Brian Ray

    2010-06-01

    Prior work on active aerodynamic load control (AALC) of wind turbine blades has demonstrated that appropriate use of this technology has the potential to yield significant reductions in blade loads, leading to a decrease in wind cost of energy. While the general concept of AALC is usually discussed in the context of multiple sensors and active control devices (such as flaps) distributed over the length of the blade, most work to date has been limited to consideration of a single control device per blade with very basic Proportional Derivative controllers, due to limitations in the aeroservoelastic codes used to perform turbine simulations. This work utilizes a new aeroservoelastic code developed at Delft University of Technology to model the NREL/Upwind 5 MW wind turbine to investigate the relative advantage of utilizing multiple-device AALC. System identification techniques are used to identify the frequencies and shapes of turbine vibration modes, and these are used with modern control techniques to develop both Single-Input Single-Output (SISO) and Multiple-Input Multiple-Output (MIMO) LQR flap controllers. Comparison of simulation results with these controllers shows that the MIMO controller does yield some improvement over the SISO controller in fatigue load reduction, but additional improvement is possible with further refinement. In addition, a preliminary investigation shows that AALC has the potential to reduce off-axis gearbox loads, leading to reduced gearbox bearing fatigue damage and improved lifetimes.

  9. Space Launch System Booster Separation Aerodynamic Testing in the NASA Langley Unitary Plan Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.; Pinier, Jeremy T.; Chan, David T.; Crosby, William A.

    2016-01-01

    A wind-tunnel investigation of a 0.009 scale model of the Space Launch System (SLS) was conducted in the NASA Langley Unitary Plan Wind Tunnel to characterize the aerodynamics of the core and solid rocket boosters (SRBs) during booster separation. High-pressure air was used to simulate plumes from the booster separation motors (BSMs) located on the nose and aft skirt of the SRBs. Force and moment data were acquired on the core and SRBs. These data were used to corroborate computational fluid dynamics (CFD) calculations that were used in developing a booster separation database. The SRBs could be remotely positioned in the x-, y-, and z-direction relative to the core. Data were acquired continuously while the SRBs were moved in the axial direction. The primary parameters varied during the test were: core pitch angle; SRB pitch and yaw angles; SRB nose x-, y-, and z-position relative to the core; and BSM plenum pressure. The test was conducted at a free-stream Mach number of 4.25 and a unit Reynolds number of 1.5 million per foot.

  10. Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system.

    PubMed

    Yao, Jianing; Thompson, Kevin P; Ma, Bin; Ponting, Michael; Rolland, Jannick P

    2016-08-22

    In this paper, we develop the methodology, including the refraction correction, geometrical thickness correction, coordinate transformation, and layer segmentation algorithms, for 3D rendering and metrology of a layered spherical gradient refractive index (S-GRIN) lens based on the imaging data collected by an angular scan optical coherence tomography (OCT) system. The 3D mapping and rendering enables direct 3D visualization and internal defect inspection of the lens. The metrology provides assessment of the surface geometry, the lens thickness, the radii of curvature of the internal layer interfaces, and the misalignment of the internal S-GRIN distribution with respect to the lens surface. The OCT metrology results identify the manufacturing defects, and enable targeted process development for optimizing the manufacturing parameters. The newly fabricated S-GRIN lenses show up to a 7x spherical aberration reduction that allows a significantly increased utilizable effective aperture. PMID:27557217

  11. Advanced Electric Systems and Aerodynamics for Efficiency Improvements in Heavy Duty Trucks

    SciTech Connect

    Larry Slone; Jeffrey Birkel

    2007-10-31

    The Advanced Electric Systems and Aerodynamics for Efficiency Improvements in Heavy Duty Trucks program (DE-FC26-04NT42189), commonly referred to as the AES program, focused on areas that will primarily benefit fuel economy and improve heat rejection while driving over the road. The AES program objectives were to: (1) Analyze, design, build, and test a cooling system that provided a minimum of 10 percent greater heat rejection in the same frontal area with no increase in parasitic fan load. (2) Realize fuel savings with advanced power management and acceleration assist by utilizing an integrated starter/generator (ISG) and energy storage devices. (3) Quantify the effect of aerodynamic drag due to the frontal shape mandated by the area required for the cooling system. The program effort consisted of modeling and designing components for optimum fuel efficiency, completing fabrication of necessary components, integrating these components into the chassis test bed, completing controls programming, and performance testing the system both on a chassis dynamometer and on the road. Emission control measures for heavy-duty engines have resulted in increased engine heat loads, thus introducing added parasitic engine cooling loads. Truck electrification, in the form of thermal management, offers technological solutions to mitigate or even neutralize the effects of this trend. Thermal control offers opportunities to avoid increases in cooling system frontal area and forestall reduced fuel economy brought about by additional aerodynamic vehicle drag. This project explored such thermal concepts by installing a 2007 engine that is compliant with current regulations and bears additional heat rejection associated with meeting these regulations. This newer engine replaced the 2002 engine from a previous project that generated less heat rejection. Advanced power management, utilizing a continuously optimized and controlled power flow between electric components, can offer additional

  12. Computational Design and Analysis of a Micro-Tab Based Aerodynamic Loads Control System for Lifting Surfaces

    SciTech Connect

    Van Dam, C P; Nakafuji, D Y; Bauer, C; Chao, D; Standish, K

    2002-11-01

    A computational design and analysis of a microtab based aerodynamic loads control system is presented. The microtab consists of a small tab that emerges from a wing approximately perpendicular to its surface in the vicinity of its trailing edge. Tab deployment on the upper side of the wing causes a decrease in the lift generation whereas deployment on the pressure side causes an increase. The computational methods applied in the development of this concept solve the governing Reynolds-averaged Navier-Stokes equations on structured, overset grids. The application of these methods to simulate the flows over lifting surface including the tabs has been paramount in the development of these devices. The numerical results demonstrate the effectiveness of the microtab and that it is possible to carry out a sensitivity analysis on the positioning and sizing of the tabs before they are implemented in successfully controlling the aerodynamic loads.

  13. An experimental study of nanoparticle focusing with aerodynamic lenses

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoliang; McMurry, Peter H.

    2006-12-01

    High sampling efficiencies of analyte ions, molecules or particles are needed to maximize the sensitivity of mass spectrometers. "Ion funnels", which utilize electrodynamic focusing, have been shown to effectively focus ions with mass-to-charge ratio (m/z) ranging from ~100 to 5000. Focusing efficiencies of ion funnels drop for higher m/z values because very high voltages are needed to overcome the particle inertia. Conventional "aerodynamic lenses" utilize inertia to focus down to 25 nm in diameter (~5 MDa); to date, Brownian diffusion has prevented the effective focusing of particles smaller than this. We recently reported a design procedure that should, in principle, extend focusing with aerodynamic lenses to particles as small as 3 nm (~10 kDa), thereby bridging the gap between the ion funnel and the conventional aerodynamic lenses. In this paper, we report for the first time experimental results for the performance of these new "nanolenses". Measurements were done using spherical oil droplets, proteins, and sodium chloride particles ranging in size from 3 to 30 nm diameter. We found that particle transport efficiencies from atmospheric pressure to vacuum through the aerodynamic lens system were greater than 80% for 10-30 nm particles, and greater than 50% for a ~3.8 nm protein (Lysozyme from chicken egg white, molecular weight 14.3 kDa). Particle beam diameters were about a factor of two greater than predicted by our numerical simulations, but provide clear evidence that the nanolenses effectively focus all three particle types.

  14. Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells

    NASA Astrophysics Data System (ADS)

    Alkandry, Hicham

    Future missions to Mars, including sample-return and human-exploration missions, may require alternative entry, descent, and landing technologies in order to perform pinpoint landing of heavy vehicles. Two such alternatives are propulsive deceleration (PD) and reaction control systems (RCS). PD can slow the vehicle during Mars atmospheric descent by directing thrusters into the incoming freestream. RCS can provide vehicle control and steering by inducing moments using thrusters on the hack of the entry capsule. The use of these PD and RCS jets, however, involves complex flow interactions that are still not well understood. The fluid interactions induced by PD and RCS jets for Mars-entry vehicles in hypersonic freestream conditions are investigated using computational fluid dynamics (CFD). The effects of central and peripheral PD configurations using both sonic and supersonic jets at various thrust conditions are examined in this dissertation. The RCS jet is directed either parallel or transverse to the freestream flow at different thrust conditions in order to examine the effects of the thruster orientation with respect to the center of gravity of the aeroshell. The physical accuracy of the computational method is also assessed by comparing the numerical results with available experimental data. The central PD configuration decreases the drag force acting on the entry capsule due to a shielding effect that prevents mass and momentum in the hypersonic freestream from reaching the aeroshell. The peripheral PD configuration also decreases the drag force by obstructing the flow around the aeroshell and creating low surface pressure regions downstream of the PD nozzles. The Mach number of the PD jets, however, does not have a significant effect on the induced fluid interactions. The reaction control system also alters the flowfield, surface, and aerodynamic properties of the aeroshell, while the jet orientation can have a significant effect on the control effectiveness

  15. Characterization of Aerodynamic Interactions with the Mars Science Laboratory Reaction Control System Using Computation and Experiment

    NASA Technical Reports Server (NTRS)

    Schoenenberger, Mark; VanNorman, John; Rhode, Matthew; Paulson, John

    2013-01-01

    On August 5 , 2012, the Mars Science Laboratory (MSL) entry capsule successfully entered Mars' atmosphere and landed the Curiosity rover in Gale Crater. The capsule used a reaction control system (RCS) consisting of four pairs of hydrazine thrusters to fly a guided entry. The RCS provided bank control to fly along a flight path commanded by an onboard computer and also damped unwanted rates due to atmospheric disturbances and any dynamic instabilities of the capsule. A preliminary assessment of the MSL's flight data from entry showed that the capsule flew much as predicted. This paper will describe how the MSL aerodynamics team used engineering analyses, computational codes and wind tunnel testing in concert to develop the RCS system and certify it for flight. Over the course of MSL's development, the RCS configuration underwent a number of design iterations to accommodate mechanical constraints, aeroheating concerns and excessive aero/RCS interactions. A brief overview of the MSL RCS configuration design evolution is provided. Then, a brief description is presented of how the computational predictions of RCS jet interactions were validated. The primary work to certify that the RCS interactions were acceptable for flight was centered on validating computational predictions at hypersonic speeds. A comparison of computational fluid dynamics (CFD) predictions to wind tunnel force and moment data gathered in the NASA Langley 31-Inch Mach 10 Tunnel was the lynch pin to validating the CFD codes used to predict aero/RCS interactions. Using the CFD predictions and experimental data, an interaction model was developed for Monte Carlo analyses using 6-degree-of-freedom trajectory simulation. The interaction model used in the flight simulation is presented.

  16. 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.

  17. Imaging of aphakic intraocular lens with a slit-scanning tomography system

    NASA Astrophysics Data System (ADS)

    Oliveira, Cristina M.; Almeida, J. B.; Franco, S.

    2011-05-01

    Nowadays, cataract extraction with IOL implantation aims not only to restore the crystalline lens' transparency, but also to improve patients' retinal image quality. The refractive outcome and visual quality in pseudophakic eyes is mainly determined by the combination of corneal and internal optics resulting from the implanted IOLs. The optical function of the IOLs depends on its position in the eye. The IOL distance to the corneal apex determines the optical power needed for optical correction. In this paper it is described the usage of a slit-scanning imaging system to determine IOL positioning. Through the projection of the light from a slit onto the eye, this tomography system allows to acquire multiple sections of the anterior eye segment, at different meridians. The developed system's software corrects geometric and optical distortion of the images and provides 3-dimentional models of the eye's structures from the 2-dimensional sections. With this noninvasive technique, cross-sectional images of an eye with an aphakic IOL were obtained in order to reconstruct its 3- dimensional model of the lens and assess its position in the anterior segment camera.

  18. A NUMERICAL CHARACTERIZATION OF PARTICLE BEAM COLLIMATION BY AN AERODYNAMIC LENS-NOZZLE SYSTEM PART I: AN INDIVIDUAL LENS OR NOZZLE. (R825391)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  19. The development and application of aerodynamic uncertainties in the design of the entry trajectory and flight control system of the Space Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Gamble, J. D.; Young, J. C.

    1982-01-01

    In connection with the decision to conduct with the Shuttle an orbital, manned mission on its first launch, certain problems arose related to mission safety, which had to be provided without the benefit of either a graduated flight test program or an initial unmanned flight concept. In an attempt to overcome these problems, the philosophy was adopted to provide a reasonable estimate of maximum possible errors in the preflight predicted aerodynamics. The flight control system (FCS) was to be certified on the basis of the estimated errors prior to STS-1. A set of 'worst case' aerodynamic uncertainties, defined as variations, was developed. As part of the first flight certification, variations, combined with other system uncertainties, were used to 'stress' the FCS through a multitude of simulations. Attention is given to an Orbiter description, the entry mission, the correlation of aerodynamic uncertainties, the application of aerodynamic variation in FCS and trajectory design, and the flight test results.

  20. Space Launch System Liftoff and Transition Aerodynamic Characterization in the NASA Langley 14- by 22-Foot Subsonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Pinier, Jeremy T.; Erickson, Gary E.; Paulson, John W.; Tomek, William G.; Bennett, David W.; Blevins, John A.

    2015-01-01

    A 1.75% scale force and moment model of the Space Launch System was tested in the NASA Langley Research Center 14- by 22-Foot Subsonic Wind Tunnel to quantify the aerodynamic forces that will be experienced by the launch vehicle during its liftoff and transition to ascent flight. The test consisted of two parts: the first was dedicated to measuring forces and moments for the entire range of angles of attack (0deg to 90deg) and roll angles (0 deg. to 360 deg.). The second was designed to measure the aerodynamic effects of the liftoff tower on the launch vehicle for ground winds from all azimuthal directions (0 deg. to 360 deg.), and vehicle liftoff height ratios from 0 to 0.94. This wind tunnel model also included a set of 154 surface static pressure ports. Details on the experimental setup, and results from both parts of testing are presented, along with a description of how the wind tunnel data was analyzed and post-processed in order to develop an aerodynamic database. Finally, lessons learned from experiencing significant dynamics in the mid-range angles of attack due to steady asymmetric vortex shedding are presented.

  1. Development of dielectric elastomer driven micro-optical zoom lens system

    NASA Astrophysics Data System (ADS)

    Kim, Hyunseok; Park, Jongkil; Chuc, Nguyen Huu; Choi, H. R.; Nam, J. D.; Lee, Y.; Jung, H. S.; Koo, J. C.

    2007-04-01

    Normally, various micro-scale devices adopt electromechanical actuators for their basic mechanical functions. Those types of actuators require a complicated power transfer system even for generating a tiny scale motion. Since the mechanical power transfer system for the micro-scale motion may require many components, the system design to fit those components into a small space is always challenging. Micro-optical zoom lens systems are recently popularly used for many portable IT devices such as digital cameras, camcorder, and cell phones, Noting the advantages of EAP actuators over the conventional electromechanical counterparts in terms of simple actuator mechanisms, a micro-optic device that is driven with the EAP actuator is introduced in the present work. EAP material selection, device design and fabrication will be also delineated.

  2. Weak lensing by intergalactic ministructures in quadruple lens systems: simulation and detection

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryuichi; Inoue, Kaiki Taro

    2014-05-01

    We investigate the weak lensing effects of line-of-sight structures on quadruple images in quasar-galaxy strong lens systems based on N-body and ray-tracing simulations that can resolve haloes with a mass of ˜105 M⊙. The intervening haloes and voids disturb the magnification ratios of lensed images as well as their relative positions due to lensing. The magnification ratios typically change by O(10 per cent) when the shifts of relative angular positions of lensed images are constrained to <0.004 arcsec. The constrained amplitudes of projected density perturbations due to line-of-sight structures are O(108) M⊙ arcsec- 2. These results are consistent with our new analytical estimate based on the two-point correlation of density fluctuations. The observed mid-infrared flux ratios for six quasar-galaxy lens systems with quadruple images agree well with the numerically estimated values without taking into account subhalos residing in the lensing galaxies. We find that the constrained mean amplitudes of projected density perturbations in the line of sight are negative, which suggests that the fluxes of lensed images are perturbed mainly by minivoids and minihaloes in underdense regions. We derive a new fitting formula for estimating the probability distribution function of magnification perturbation. We also find that the mean amplitude of magnification perturbation roughly equals the standard deviation regardless of the model parameters.

  3. Holographic lens spectrum splitting photovoltaic system for increased diffuse collection and annual energy yield

    NASA Astrophysics Data System (ADS)

    Vorndran, Shelby D.; Wu, Yuechen; Ayala, Silvana; Kostuk, Raymond K.

    2015-09-01

    Concentrating and spectrum splitting photovoltaic (PV) modules have a limited acceptance angle and thus suffer from optical loss under off-axis illumination. This loss manifests itself as a substantial reduction in energy yield in locations where a significant portion of insulation is diffuse. In this work, a spectrum splitting PV system is designed to efficiently collect and convert light in a range of illumination conditions. The system uses a holographic lens to concentrate shortwavelength light onto a smaller, more expensive indium gallium phosphide (InGaP) PV cell. The high efficiency PV cell near the axis is surrounded with silicon (Si), a less expensive material that collects a broader portion of the solar spectrum. Under direct illumination, the device achieves increased conversion efficiency from spectrum splitting. Under diffuse illumination, the device collects light with efficiency comparable to a flat-panel Si module. Design of the holographic lens is discussed. Optical efficiency and power output of the module under a range of illumination conditions from direct to diffuse are simulated with non-sequential raytracing software. Using direct and diffuse Typical Metrological Year (TMY3) irradiance measurements, annual energy yield of the module is calculated for several installation sites. Energy yield of the spectrum splitting module is compared to that of a full flat-panel Si reference module.

  4. Lamp system with a single second-lens newly designed by using the least square method for 4 LEDs

    NASA Astrophysics Data System (ADS)

    Jo, Jae Heung; Ryu, Jae Myung; Hong, Chun Gang

    2014-05-01

    It is common for many companies to use multiple LEDs to enhance the brightness of a LED lamp and, in general, four LEDs are used in the LED lamp systems. Moreover, the second-lens must be used to obtain a straight uniform illumination from LED lights. Where four LEDs are used, four second-lenses are also assembled conventionally and those four units of second-lenses are manufactured from a single mold and assembled together with the LEDs. However, this study introduces a new method of using the Least Square Method to get a uniform illumination with the divergence angle of 40 degrees with a new single injection molded lens. Thanks to this optical design with a single lens, the assembling process of LED lamp system was simplified by eliminating the complicated assembly procedure. Also, the uniformity of illumination of this newly designed lamp system was less than 14.1%.

  5. The gravitational lens system Q0957+561 in the ultraviolet

    NASA Technical Reports Server (NTRS)

    Dolan, J. F.; Michalitsianos, A. G.; Thompson, R. W.; Boyd, P. T.; Wolinski, K. G.; Bless, R. C.; Nelson, M. J.; Percival, J. W.; Taylor, M. J.; Elliot, J. L.

    1995-01-01

    Photometric and polarimetric observations of both images of the gravitationally lensed quasar Q0957+561 (z(sub em) = 1.41) were obtained in the UV in 1993 with the High Speed Photometer on board the Hubble Space Photometer on board the Hubble Space Telescope. The images exhibited no significant polarization in a bandpass centered on 2770 A (observer's frame); p less than or = 3.2 % (2 sigma upper limit) in each image. The ratio of the flux density in image A to that in image B in late 1993 had a constant valuee, 1.021 +/- 0.008, in four different UV bandpass between 1400 A and 3040 A observer's frame). These results are consistent with the prediction of the gravitation lens interpretation that the photometric ratio of the images measured simultaneously should be independent of frequency. Reprocessed archival spectra of the two images obtained between 1981 and 1983 by the International Ultraviolet Explorer (IUE) show that the photometric ratio of A to B varies between 0.96 and 2.0 in the Ly alpha emission line, and between 0.77 and 1.8 in the O VI lambda 1037 emission line (quasar rest frame). The photometric ratio of A to B at any single epoch is often significantly different in the two emission lines. Accepting the system as a gravitational lens implies that in the quasar the flux in the Ly alpha emsisson line can vary independently of the flux in the 0 IV emission line.

  6. NASP aerodynamics

    NASA Technical Reports Server (NTRS)

    Whitehead, Allen H., Jr.

    1989-01-01

    This paper discusses the critical aerodynamic technologies needed to support the development of a class of aircraft represented by the National Aero-Space Plane (NASP). The air-breathing, single-stage-to-orbit mission presents a severe challenge to all of the aeronautical disciplines and demands an extension of the state-of-the-art in each technology area. While the largest risk areas are probably advanced materials and the development of the scramjet engine, there remains a host of design issues and technology problems in aerodynamics, aerothermodynamics, and propulsion integration. The paper presents an overview of the most significant propulsion integration problems, and defines the most critical fluid flow phenomena that must be evaluated, defined, and predicted for the class of aircraft represented by the Aero-Space Plane.

  7. Research on aspheric focusing lens processing and testing technology in the high-energy laser test system

    NASA Astrophysics Data System (ADS)

    Liu, Dan; Fu, Xiu-hua; Jia, Zong-he; Wang, Zhe; Dong, Huan

    2014-08-01

    In the high-energy laser test system, surface profile and finish of the optical element are put forward higher request. Taking a focusing aspherical zerodur lens with a diameter of 100mm as example, using CNC and classical machining method of combining surface profile and surface quality of the lens were investigated. Taking profilometer and high power microscope measurement results as a guide, by testing and simulation analysis, process parameters were improved constantly in the process of manufacturing. Mid and high frequency error were trimmed and improved so that the surface form gradually converged to the required accuracy. The experimental results show that the final accuracy of the surface is less than 0.5μm and the surface finish is □, which fulfils the accuracy requirement of aspherical focusing lens in optical system.

  8. Observations of the new gravitational lens system UM 673 = Q 0142-100

    NASA Astrophysics Data System (ADS)

    Surdej, J.; Magain, P.; Swings, J.-P.; Borgeest, U.; Courvoisier, T. J.-L.; Kayer, R.; Kellermann, K. I.; Kuhr, H.; Refsdal, S.

    1988-06-01

    The authors have recently initiated a high resolution direct imaging survey of a selected sample of highly luminous quasars (HLQs). The observations are carried out with the 2.2 m telescope at ESO, and with the VLA at the NRAO, New Mexico. Following the first observing run at ESO, the authors have reported the discovery of a new gravitational lens system for the HLQ UM 673 = Q 0142-100. Additional observations supporting this interpretation are discussed here. Application of gravitational optometry to this system is given: a value of M0 = 2.4×1011M_sun; is derived for the mass of the lensing galaxy located between UM 673 A and B and a most likely estimate of Δt = 7 weeks is found for the expected delay between the arrival times of a similar variability event in the two lensed images of the quasar (H0 = 75 km s-1Mpc-1, q0 = 0).

  9. Modeling State-Space Aeroelastic Systems Using a Simple Matrix Polynomial Approach for the Unsteady Aerodynamics

    NASA Technical Reports Server (NTRS)

    Pototzky, Anthony S.

    2008-01-01

    A simple matrix polynomial approach is introduced for approximating unsteady aerodynamics in the s-plane and ultimately, after combining matrix polynomial coefficients with matrices defining the structure, a matrix polynomial of the flutter equations of motion (EOM) is formed. A technique of recasting the matrix-polynomial form of the flutter EOM into a first order form is also presented that can be used to determine the eigenvalues near the origin and everywhere on the complex plane. An aeroservoelastic (ASE) EOM have been generalized to include the gust terms on the right-hand side. The reasons for developing the new matrix polynomial approach are also presented, which are the following: first, the "workhorse" methods such as the NASTRAN flutter analysis lack the capability to consistently find roots near the origin, along the real axis or accurately find roots farther away from the imaginary axis of the complex plane; and, second, the existing s-plane methods, such as the Roger s s-plane approximation method as implemented in ISAC, do not always give suitable fits of some tabular data of the unsteady aerodynamics. A method available in MATLAB is introduced that will accurately fit generalized aerodynamic force (GAF) coefficients in a tabular data form into the coefficients of a matrix polynomial form. The root-locus results from the NASTRAN pknl flutter analysis, the ISAC-Roger's s-plane method and the present matrix polynomial method are presented and compared for accuracy and for the number and locations of roots.

  10. Longitudinal aerodynamic characteristics of an externally blown flap powered lift model with several propulsive system simulators

    NASA Technical Reports Server (NTRS)

    Hoad, D. R.

    1974-01-01

    An investigation of a four-engine externally blown flap (EBF) powered-lift transport was conducted in the Langley V/STOL tunnel to determine the effect of different engine configurations on the longitudinal aerodynamic characteristics. The different engine configurations were simulated by five different sets of propulsion simulators on a single aircraft model. Longitudinal aerodynamic data were obtained for each simulator on each flap deflection corresponding to cruise, take-off, and landing at a range of angles of attack and various thrust coefficients. The bypass ratio (BPR) 6.2 engine simulator provided the best lift and drag characteristics of the five simulators tested in the take-off and landing configurations. The poor performance of the BPR 10.0 and 3.2 engine simulators can be attributed to a mismatch of engine-model sizes or poor engine location and orientation. Isolated engine wake surveys indicated that a reasonable assessment of the aerodynamic characteristics of an engine-wing-flap configuration could be made if qualitative information were available which defined the engine wake characteristics. All configurations could be trimmed easily with relatively small horizontal-tail incidence angles; however, the take-off landing configurations required a high-lift tail.

  11. High-temperature deformation field measurement by combining transient aerodynamic heating simulation system and reliability-guided digital image correlation

    NASA Astrophysics Data System (ADS)

    Pan, Bing; Wu, Dafang; Xia, Yong

    2010-09-01

    To determine the full-field high-temperature thermal deformation of the structural materials used in high-speed aerospace flight vehicles, a novel non-contact high-temperature deformation measurement system is established by combining transient aerodynamic heating simulation device with the reliability-guided digital image correlation (RG-DIC). The test planar sample with size varying from several mm 2 to several hundreds mm 2 can be heated from room temperature to 1100 °C rapidly and accurately using the infrared radiator of the transient aerodynamic heating simulation system. The digital images of the test sample surface at various temperatures are recorded using an ordinary optical imaging system. To cope with the possible local decorrelated regions caused by black-body radiation within the deformed images at the temperatures over 450 °C, the RG-DIC technique is used to extract full-field in-plane thermal deformation from the recorded images. In validation test, the thermal deformation fields and the values of coefficient of thermal expansion (CTEs) of a chromiumnickel austenite stainless steel sample from room temperature to 550 °C is measured and compared with the well-established handbook value, confirming the effectiveness and accuracy of the proposed technique. The experimental results reveal that the present system using an ordinary optical imaging system, is able to accurately measure full-field thermal deformation of metals and alloys at temperatures not exceeding 600 °C.

  12. Modelling Napl Dissolution from Lens and Pools Under Varying Flowfields in Heterogeneous Subsurface Systems

    NASA Astrophysics Data System (ADS)

    Prakash, P.; Nambi, I. M.

    2011-12-01

    Non- Aqueous Phase Liquids (NAPLs) such as chlorinated organic solvents are major sources of groundwater contamination throughout the world. The non-uniform distribution of these contaminants as NAPL pools and residual NAPL zones introduce additional spatial heterogeneity in the hydrological parameters such as porosity and permeability. Bench scale dissolution studies were carried out and a conceptual contaminant transport model was developed to predict the downstream NAPL concentrations in aqueous phase. The dissolution studies were carried out in a bench scale 2-D sand tank reactor for multiple NAPL configurations and various initial NAPL saturations. A complex heterogeneous subsurface system mimicking NAPL as residuals, NAPL as lens and NAPL as pools was created by embedding more than one NAPL contaminated zone of coarse sand within a clean NAPL free zone of fine sand. Dissolved NAPL concentrations were measured along the downstream of NAPL source zone. A 2-D conceptual contaminant transport model was developed and validated which successfully accounts for NAPL interphase mass transfer limitation under varying flow fields in a saturated heterogeneous subsurface systems. The analysis of multiple lens experimental data revealed that initial NAPL saturations and relative permeability have significant effect in altering mass transfer characteristics which affects the efficacy of any remedial effort to decontaminate groundwater. Non equilibrium concentrations of NAPL were observed near the source zone during dissolution from high initial NAPL saturations, whereas tailing concentrations with steep decline from equilibrium state were seen at later times. The rate limited conditions occurred much earlier under heterogeneous soil conditions when compared to those observed by researchers under homogeneous soil conditions. This behavior was attributed to the large changes in aqueous permeability fields occurring with the progress of dissolution process. Mathematical

  13. Structural Testing of a 6m Hypersonic Inflatable Aerodynamic Decelerator System

    NASA Technical Reports Server (NTRS)

    Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.

    2015-01-01

    NASA is developing low ballistic coefficient technologies to support the Nations long-term goal of landing humans on Mars. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current and future launch vehicle fairing limitations. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) are being developed to circumvent this limitation and are now considered a leading technology to enable landing of heavy payloads on Mars. At the beginning of 2014, a 6m diameter HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify its structural performance under flight-relevant loads. The inflatable structure was constructed into a 60 degree sphere-cone configuration using nine inflatable torus segments composed of fiber-reinforced thin films. The inflatable tori were joined together using adhesives and high-strength textile woven structural straps. These straps help distribute the load throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials that are designed to protect the inflatable structure from heat loads that would be seen in flight during atmospheric entry. A custom test fixture was constructed to perform the static load test series. The fixture consisted of a round structural tub with enough height and width to allow for displacement of the HIAD test article as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The rigid centerbody of the HIAD was mounted to a pedestal in the center of the structural tub. Using an impermeable membrane draped over the HIAD test article, an airtight seal was created with the top rim of the static load tub. This seal allowed partial vacuum to be pulled beneath the HIAD resulting in a uniform static pressure load applied to the outer surface. Using this technique, the test article

  14. Asymptotic solutions for the case of nearly symmetric gravitational lens systems

    NASA Astrophysics Data System (ADS)

    Wertz, O.; Pelgrims, V.; Surdej, J.

    2012-08-01

    Gravitational lensing provides a powerful tool to determine the Hubble parameter H0 from the measurement of the time delay Δt between two lensed images of a background variable source. Nevertheless, knowledge of the deflector mass distribution constitutes a hurdle. We propose in the present work interesting solutions for the case of nearly symmetric gravitational lens systems. For the case of a small misalignment between the source, the deflector and the observer, we first consider power-law (ɛ) axially symmetric models for which we derive an analytical relation between the amplification ratio and source position which is independent of the power-law slope ɛ. According to this relation, we deduce an expression for H0 also irrespective of the value ɛ. Secondly, we consider the power-law axially symmetric lens models with an external large-scale gravitational field, the shear γ, resulting in the so-called ɛ-γ models, for which we deduce simple first-order equations linking the model parameters and the lensed image positions, the latter being observable quantities. We also deduce simple relations between H0 and observables quantities only. From these equations, we may estimate the value of the Hubble parameter in a robust way. Nevertheless, comparison between the ɛ-γ and singular isothermal ellipsoid (SIE) models leads to the conclusion that these models remain most often distinct. Therefore, even for the case of a small misalignment, use of the first-order equations and precise astrometric measurements of the positions of the lensed images with respect to the centre of the deflector enables one to discriminate between these two families of models. Finally, we confront the models with numerical simulations to evaluate the intrinsic error of the first-order expressions used when deriving the model parameters under the assumption of a quasi-alignment between the source, the deflector and the observer. From these same simulations, we estimate for the case of the

  15. 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.

  16. 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.

  17. Automated synthesis of both the topology and numerical parameters for seven patented optical lens systems using genetic programming

    NASA Astrophysics Data System (ADS)

    Jones, Lee W.; Al-Sakran, Sameer H.; Koza, John R.

    2005-08-01

    This paper describes how genetic programming was used as an automated invention machine to synthesize both the topology and numerical parameters for seven previously patented optical lens systems, including one aspherical system and one issued in the 21st-century. Two of the evolved optical lens systems infringe the claims of the patents and the others are novel solutions that satisfy the design goals stated in the patent. The automatic synthesis was done "from scratch"--that is, without starting from a pre-existing good design and without pre-specifying the number of lenses, the topological layout of the lenses, or the numerical parameters of the lenses. Genetic programming is a form of evolutionary computation used to automatically solve problems. It starts from a high-level statement of what needs to be done and progressively breeds a population of candidate individuals over many generations using the principle of Darwinian natural selection and genetic recombination. The paper describes how genetic programming created eyepieces that duplicated the functionality of seven previously patented lens systems. The seven designs were created in a substantially similar and routine way, suggesting that the use of genetic programming in the automated design of both the topology and numerical parameters for optical lens systems may have widespread utility.

  18. Angular domain optical imaging using a micromachined tunnel array and a Keplerian lens system.

    PubMed

    Vasefi, F; Kaminska, B; Chapman, G H

    2008-01-01

    Angular Domain Imaging (ADI) is a technique that selects quasi-ballistic photons exiting from a highly scattering medium by an array of silicon micromachined micro-tunnels. Each channel has a limited acceptance angle based on its geometry therefore those photons that traverse within the acceptance angle of the micro-tunnels will be detected by the imager. In this paper, the ADI technique has been investigated by using newly micromachined tunnels with less spacing between the channels. Also, a Keplerian lens system is used to remove the diffracted light exiting from the tunnels that results due to internal reflection of scattered photons along the tunnel's walls. With these changes, improvements in the spatial resolution including sharper edges and definition were observed. The experiments show that the new setup can resolve test structure objects down to 100 mum embedded midway through a 2 cm long cuvette filled with 0.3% Intralipid solution in the 808 nm wavelength.

  19. Speckle-reduced holographic display by modulating complex amplitude in single-lens system

    NASA Astrophysics Data System (ADS)

    Chang, Chenliang; Xia, Jun; Qi, Yijun; Yuan, Caojin; Nie, Shouping

    2016-06-01

    This paper proposes a method for calculating phase-only computer-generated hologram (CGH) in holographic display with reduced speckle noise. The method works by encoding the desired complex-amplitude field of object into a phase-only CGH by a linear canonical transform algorithm. The complex-amplitude field can then be reconstructed independently from the encoded CGH using a filter at the Fourier plane of a single-lens optical system. The feasibility and effectiveness of the proposed method was verified by a simulation experiment. An optical experiment for holographic display was also conducted with reduced speckle using a single phase-only spatial-light modulator. The object was, in fact, reconstructed with different depth of focus clearly without speckle noise due to the simultaneous modulation of both amplitude and phase, confirming our method's ability to suppress speckle noise in holographic displays by modulating complex amplitude in three-dimensional space.

  20. Thin film fabrication and system integration test run for a microactuator for a tuneable lens

    NASA Astrophysics Data System (ADS)

    Hoheisel, Dominik; Rissing, Lutz

    2014-03-01

    An electromagnetic microactuator, for controlling of a tuneable lens, with an integrated electrostatic element is fabricated by thin film technology. The actuator consists of two parts: the first part with microcoil and flux guide and the second part with a ring shaped back iron on a polyimide membrane. The back iron is additionally useable as electrode for electrostatic measurement of the air gap and for electrostatic actuation. By attracting the back iron an optical liquid is displaced and forms a liquid lens inside the back iron ring covered by the membrane. For testing the thin film fabrication sequence, up-scaled systems are generated in a test run. To fabricate the flux guide in an easy and quick way, a Ni-Fe foil with a thickness of 50 μm is laminated on the Si-wafer. This foil is also utilized in the following fabrication sequence as seed layer for electroplating. Compared to Ni-Fe structures deposited by electroplating, the foil is featuring better soft magnetic properties. The foil is structured by wet chemical etching and the backside of the wafer is structured by deep reactive ion etching (DRIE). For post fabrication thinning, the polyimide membrane is treated by oxygen plasma etching. To align the back iron to the microcoil and the flux guide, a flip-chip-bonder is used during test run of system integration. To adjust a constant air gap, a water solvable polymer is tested. A two component epoxy and a polyimide based glue are compared for their bonding properties of the actuator parts.

  1. An all-silicone zoom lens in an optical imaging system

    NASA Astrophysics Data System (ADS)

    Zhao, Cun-Hua

    2013-09-01

    An all-silicone zoom lens is fabricated. A tunable metal ringer is fettered around the side edge of the lens. A nylon rope linking a motor is tied, encircling the notch in the metal ringer. While the motor is operating, the rope can shrink or release to change the focal length of the lens. A calculation method is developed to obtain the focal length and the zoom ratio. The testing is carried out in succession. The testing values are compared with the calculated ones, and they tally with each other well. Finally, the imaging performance of the all-silicone lens is demonstrated. The all-silicone lens has potential uses in cellphone cameras, notebook cameras, micro monitor lenses, etc.

  2. Aerodynamics overview of the ground transportation systems (GTS) project for heavy vehicle drag reduction

    SciTech Connect

    Gutierrez, W.T.; Hassan, B.; Croll, R.H.; Rutledge, W.H.

    1995-12-31

    The focus of the research was to investigate the fundamental aerodynamics of the base flow of a tractor trailer that would prove useful in fluid flow management. Initially, industry design needs and constraints were defined. This was followed by an evaluation of state-of-the-art Navier-Stokes based computational fluid dynamics tools. Analytical methods were then used in combination with computational tools in a design process. Several geometries were tested at 1:8 scale in a low speed wind tunnel. In addition to the baseline geometry, base add-on devices of the class of ogival boattails and slants were analyzed.

  3. Integrated Design Engineering Analysis (IDEA) Environment - Aerodynamics, Aerothermodynamics, and Thermal Protection System Integration Module

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hilmi N.

    2011-01-01

    This report documents the work performed during from March 2010 October 2011. The Integrated Design and Engineering Analysis (IDEA) environment is a collaborative environment based on an object-oriented, multidisciplinary, distributed environment using the Adaptive Modeling Language (AML) as the underlying framework. This report will focus on describing the work done in the area of extending the aerodynamics, and aerothermodynamics module using S/HABP, CBAERO, PREMIN and LANMIN. It will also detail the work done integrating EXITS as the TPS sizing tool.

  4. Computational aerodynamics and supercomputers

    NASA Technical Reports Server (NTRS)

    Ballhaus, W. F., Jr.

    1984-01-01

    Some of the progress in computational aerodynamics over the last decade is reviewed. The Numerical Aerodynamic Simulation Program objectives, computational goals, and implementation plans are described.

  5. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    PubMed

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm. PMID:27661578

  6. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    PubMed

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm.

  7. An automated system for the acoustical and aerodynamic characterization of small air moving devices

    NASA Astrophysics Data System (ADS)

    Schmitt, Jeff G.; Nelson, David A.; Phillips, John

    2005-09-01

    A plenum fixture for use in the measurement of acoustic emissions of air moving devices used to cool electronic equipment under the actual aerodynamic conditions of operation has been standardized in ISO 10302 and ANSI S12.11. This fixture has proven to be a valuable tool for use in the characterization of these devices. However, as many in industry have discovered, the construction of the plenum to the standardized specifications can quite complex, and the use of the plenum to fully characterize air moving devices can be quite laborious and tedious. Under contract to the NASA Glenn Research Center, which has a significant interest in the acoustic emissions of the air moving devices it uses to cool racks and payloads that are installed on the International Space Station, the authors have developed a fully automated fan test plenum that operates under software control. This plenum has been developed to facilitate rapid acoustic characterization of fans and other air moving devices, both independently and when operating into real world inlet conditions, obstructions and aerodynamic loads. The plenum slider has been calibrated to allow full development of fan curve data in parallel with acoustic emission data.

  8. Adaptive Optics Imaging of the CLASS Gravitational Lens System B1359+154 with the Canada-France-Hawaii Telescope.

    PubMed

    Rusin; Hall; Nichol; Marlow; Richards; Myers

    2000-04-20

    We present adaptive optics imaging of the CLASS gravitational lens system B1359+154 obtained with the Canada-France-Hawaii Telescope (CFHT) in the infrared K band. The observations show at least three brightness peaks within the ring of lensed images, which we identify as emission from multiple lensing galaxies. The results confirm the suspected compound nature of the lens, as deduced from preliminary mass modeling. The detection of several additional nearby galaxies suggests that B1359+154 is lensed by the compact core of a small galaxy group. We attempted to produce an updated lens model based on the CFHT observations and new 5 GHz radio data obtained with the MERLIN array, but there are too few constraints to construct a realistic model at this time. The uncertainties inherent with modeling compound lenses make B1359+154 a challenging target for Hubble constant determination through the measurement of differential time delays. However, time delays will offer additional constraints to help pin down the mass model. This lens system therefore presents a unique opportunity to directly measure the mass distribution of a galaxy group at intermediate redshift.

  9. Adaptive Optics Imaging of the CLASS Gravitational Lens System B1359+154 with the Canada-France-Hawaii Telescope.

    PubMed

    Rusin; Hall; Nichol; Marlow; Richards; Myers

    2000-04-20

    We present adaptive optics imaging of the CLASS gravitational lens system B1359+154 obtained with the Canada-France-Hawaii Telescope (CFHT) in the infrared K band. The observations show at least three brightness peaks within the ring of lensed images, which we identify as emission from multiple lensing galaxies. The results confirm the suspected compound nature of the lens, as deduced from preliminary mass modeling. The detection of several additional nearby galaxies suggests that B1359+154 is lensed by the compact core of a small galaxy group. We attempted to produce an updated lens model based on the CFHT observations and new 5 GHz radio data obtained with the MERLIN array, but there are too few constraints to construct a realistic model at this time. The uncertainties inherent with modeling compound lenses make B1359+154 a challenging target for Hubble constant determination through the measurement of differential time delays. However, time delays will offer additional constraints to help pin down the mass model. This lens system therefore presents a unique opportunity to directly measure the mass distribution of a galaxy group at intermediate redshift. PMID:10770697

  10. Telescopic vision contact lens

    NASA Astrophysics Data System (ADS)

    Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

    2011-03-01

    We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

  11. An Aerodynamic Force Estimation Method for Winged Models at the JAXA 60cm Magnetic Suspension and Balance System

    NASA Astrophysics Data System (ADS)

    澤田, 秀夫

    The aerodynamic performance of an AGARD-B model, as an example of a winged model, was measured in a low-speed wind tunnel equipped with the JAXA 60cm Magnetic Suspension and Balance System (MSBS). The flow speed was in the range between 25m/s and 35m/s, and the angle of attack and the yaw angle were in the range of [- 8, 4] and [- 3, 3] degrees, respectively. Six components of the aerodynamic force were evaluated by using the control coil currents of the MSBS. In evaluating the drag, the effect of the lift on the drag must be evaluated at MSBS when the lift is much larger than drag. A new evaluation method for drag and lift was proposed and was examined successfully by subjecting the model to the same loads as in the wind tunnel test. The drag coefficient at zero lift and the derivatives of the lift and pitching moment coefficient with respect to the angle of attack were evaluated and compared with other source data sets. The obtained data agreed well with the corresponding values of the other sources. The side force, yawing moment and rolling moment coefficients were also evaluated on the basis of corresponding calibration test results, and reasonable results were obtained, although they could not be compared due to the lack of reliable data sets.

  12. Experimental aerodynamic and acoustic model testing of the Variable Cycle Engine (VCE) testbed coannular exhaust nozzle system

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.; Morris, P. M.

    1980-01-01

    Aerodynamic performance and jet noise characteristics of a one sixth scale model of the variable cycle engine testbed exhaust system were obtained in a series of static tests over a range of simulated engine operating conditions. Model acoustic data were acquired. Data were compared to predictions of coannular model nozzle performance. The model, tested with an without a hardwall ejector, had a total flow area equivalent to a 0.127 meter (5 inch) diameter conical nozzle with a 0.65 fan to primary nozzle area ratio and a 0.82 fan nozzle radius ratio. Fan stream temperatures and velocities were varied from 422 K to 1089 K (760 R to 1960 R) and 434 to 755 meters per second (1423 to 2477 feet per second). Primary stream properties were varied from 589 to 1089 K (1060 R to 1960 R) and 353 to 600 meters per second (1158 to 1968 feet per second). Exhaust plume velocity surveys were conducted at one operating condition with and without the ejector installed. Thirty aerodynamic performance data points were obtained with an unheated air supply. Fan nozzle pressure ratio was varied from 1.8 to 3.2 at a constant primary pressure ratio of 1.6; primary pressure ratio was varied from 1.4 to 2.4 while holding fan pressure ratio constant at 2.4. Operation with the ejector increased nozzle thrust coefficient 0.2 to 0.4 percent.

  13. Geometry Control System for Exploratory Shape Optimization Applied to High-Fidelity Aerodynamic Design of Unconventional Aircraft

    NASA Astrophysics Data System (ADS)

    Gagnon, Hugo

    This thesis represents a step forward to bring geometry parameterization and control on par with the disciplinary analyses involved in shape optimization, particularly high-fidelity aerodynamic shape optimization. Central to the proposed methodology is the non-uniform rational B-spline, used here to develop a new geometry generator and geometry control system applicable to the aerodynamic design of both conventional and unconventional aircraft. The geometry generator adopts a component-based approach, where any number of predefined but modifiable (parametric) wing, fuselage, junction, etc., components can be arbitrarily assembled to generate the outer mold line of aircraft geometry. A unique Python-based user interface incorporating an interactive OpenGL windowing system is proposed. Together, these tools allow for the generation of high-quality, C2 continuous (or higher), and customized aircraft geometry with fast turnaround. The geometry control system tightly integrates shape parameterization with volume mesh movement using a two-level free-form deformation approach. The framework is augmented with axial curves, which are shown to be flexible and efficient at parameterizing wing systems of arbitrary topology. A key aspect of this methodology is that very large shape deformations can be achieved with only a few, intuitive control parameters. Shape deformation consumes a few tenths of a second on a single processor and surface sensitivities are machine accurate. The geometry control system is implemented within an existing aerodynamic optimizer comprising a flow solver for the Euler equations and a sequential quadratic programming optimizer. Gradients are evaluated exactly with discrete-adjoint variables. The algorithm is first validated by recovering an elliptical lift distribution on a rectangular wing, and then demonstrated through the exploratory shape optimization of a three-pronged feathered winglet leading to a span efficiency of 1.22 under a height

  14. Characterization of a microflow cytometer with an integrated three-dimensional optofluidic lens system.

    PubMed

    Rosenauer, M; Vellekoop, M J

    2010-01-01

    Flow cytometry is a standard analytical method in cell biology and clinical diagnostics and is widely distributed for the experimental investigation of microparticle characteristics. In this work, the design, realization, and measurement results of a novel planar optofluidic flow cytometric device with an integrated three-dimensional (3D) adjustable optofluidic lens system for forward-scattering∕extinction-based biochemical analysis fabricated by silicon micromachining are presented. To our knowledge, this is the first planar cytometric system with the ability to focus light three-dimensionally on cells∕particles by the application of fluidic lenses. The single layer microfluidic platform enables versatile 3D hydrodynamic sample focusing to an arbitrary position in the channel and incorporates integrated fiber grooves for the insertion of glass fibers. To confirm the fluid dynamics and raytracing simulations and to characterize the sensor, different cell lines and sets of microparticles were investigated by detecting the extinction (axial light loss) signal, demonstrating the high sensitivity and sample discrimination capability of this analysis system. The unique features of this planar microdevice enable new biotechnological analysis techniques due to the highly increased sensitivity.

  15. Characterization of a microflow cytometer with an integrated three-dimensional optofluidic lens system.

    PubMed

    Rosenauer, M; Vellekoop, M J

    2010-01-01

    Flow cytometry is a standard analytical method in cell biology and clinical diagnostics and is widely distributed for the experimental investigation of microparticle characteristics. In this work, the design, realization, and measurement results of a novel planar optofluidic flow cytometric device with an integrated three-dimensional (3D) adjustable optofluidic lens system for forward-scattering∕extinction-based biochemical analysis fabricated by silicon micromachining are presented. To our knowledge, this is the first planar cytometric system with the ability to focus light three-dimensionally on cells∕particles by the application of fluidic lenses. The single layer microfluidic platform enables versatile 3D hydrodynamic sample focusing to an arbitrary position in the channel and incorporates integrated fiber grooves for the insertion of glass fibers. To confirm the fluid dynamics and raytracing simulations and to characterize the sensor, different cell lines and sets of microparticles were investigated by detecting the extinction (axial light loss) signal, demonstrating the high sensitivity and sample discrimination capability of this analysis system. The unique features of this planar microdevice enable new biotechnological analysis techniques due to the highly increased sensitivity. PMID:21267437

  16. Characterization of a microflow cytometer with an integrated three-dimensional optofluidic lens system

    PubMed Central

    Rosenauer, M.; Vellekoop, M. J.

    2010-01-01

    Flow cytometry is a standard analytical method in cell biology and clinical diagnostics and is widely distributed for the experimental investigation of microparticle characteristics. In this work, the design, realization, and measurement results of a novel planar optofluidic flow cytometric device with an integrated three-dimensional (3D) adjustable optofluidic lens system for forward-scattering∕extinction-based biochemical analysis fabricated by silicon micromachining are presented. To our knowledge, this is the first planar cytometric system with the ability to focus light three-dimensionally on cells∕particles by the application of fluidic lenses. The single layer microfluidic platform enables versatile 3D hydrodynamic sample focusing to an arbitrary position in the channel and incorporates integrated fiber grooves for the insertion of glass fibers. To confirm the fluid dynamics and raytracing simulations and to characterize the sensor, different cell lines and sets of microparticles were investigated by detecting the extinction (axial light loss) signal, demonstrating the high sensitivity and sample discrimination capability of this analysis system. The unique features of this planar microdevice enable new biotechnological analysis techniques due to the highly increased sensitivity. PMID:21267437

  17. Experimental aerodynamic and acoustic model testing of the Variable Cycle Engine (VCE) testbed coannular exhaust nozzle system: Comprehensive data report

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.; Morris, P. M.

    1980-01-01

    The component detail design drawings of the one sixth scale model of the variable cycle engine testbed demonstrator exhaust syatem tested are presented. Also provided are the basic acoustic and aerodynamic data acquired during the experimental model tests. The model drawings, an index to the acoustic data, an index to the aerodynamic data, tabulated and graphical acoustic data, and the tabulated aerodynamic data and graphs are discussed.

  18. The impact of a preloaded intraocular lens delivery system on operating room efficiency in routine cataract surgery

    PubMed Central

    Jones, Jason J; Chu, Jeffrey; Graham, Jacob; Zaluski, Serge; Rocha, Guillermo

    2016-01-01

    Purpose The aim of this study was to evaluate the operational impact of using preloaded intraocular lens (IOL) delivery systems compared with manually loaded IOL delivery processes during routine cataract surgeries. Methods Time and motion data, staff and surgery schedules, and cost accounting reports were collected across three sites located in the US, France, and Canada. Time and motion data were collected for manually loaded IOL processes and preloaded IOL delivery systems over four surgery days. Staff and surgery schedules and cost accounting reports were collected during the 2 months prior and after introduction of the preloaded IOL delivery system. Results The study included a total of 154 routine cataract surgeries across all three sites. Of these, 77 surgeries were performed using a preloaded IOL delivery system, and the remaining 77 surgeries were performed using a manual IOL delivery process. Across all three sites, use of the preloaded IOL delivery system significantly decreased mean total case time by 6.2%–12.0% (P<0.001 for data from Canada and the US and P<0.05 for data from France). Use of the preloaded delivery system also decreased surgeon lens time, surgeon delays, and eliminated lens touches during IOL preparation. Conclusion Compared to a manual IOL delivery process, use of a preloaded IOL delivery system for cataract surgery reduced total case time, total surgeon lens time, surgeon delays, and eliminated IOL touches. The time savings provided by the preloaded IOL delivery system provide an opportunity for sites to improve routine cataract surgery throughput without impacting surgeon or staff capacity. PMID:27382245

  19. Amoebicidal activity of a preserved contact lens multipurpose disinfecting solution compared to a disinfection/neutralisation peroxide system.

    PubMed

    Buck, S L; Rosenthal, R A; Abshire, R L

    1998-01-01

    The amoebicidal activity of a contact lens multipurpose disinfecting solution (MPDS) containing polyquaternium-1 and myristamidopropyl dimethylamine was compared to a disinfection/neutralisation peroxide system against Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites and cysts. A quantitative microtitre method was used to evaluate the solutions. The MPDS showed similar amoebicidal activity to the disinfection/neutralisation peroxide system against the trophozoites of both species and equal or more rapid activity against the cysts of both species. PMID:16303382

  20. Single Lens Dual-Aperture 3D Imaging System: Color Modeling

    NASA Technical Reports Server (NTRS)

    Bae, Sam Y.; Korniski, Ronald; Ream, Allen; Fritz, Eric; Shearn, Michael

    2012-01-01

    In an effort to miniaturize a 3D imaging system, we created two viewpoints in a single objective lens camera. This was accomplished by placing a pair of Complementary Multi-band Bandpass Filters (CMBFs) in the aperture area. Two key characteristics about the CMBFs are that the passbands are staggered so only one viewpoint is opened at a time when a light band matched to that passband is illuminated, and the passbands are positioned throughout the visible spectrum, so each viewpoint can render color by taking RGB spectral images. Each viewpoint takes a different spectral image from the other viewpoint hence yielding a different color image relative to the other. This color mismatch in the two viewpoints could lead to color rivalry, where the human vision system fails to resolve two different colors. The difference will be closer if the number of passbands in a CMBF increases. (However, the number of passbands is constrained by cost and fabrication technique.) In this paper, simulation predicting the color mismatch is reported.

  1. A Spectroscopically Confirmed Double Source Plane Lens System in the Hyper Suprime-Cam Subaru Strategic Program

    NASA Astrophysics Data System (ADS)

    Tanaka, Masayuki; Wong, Kenneth C.; More, Anupreeta; Dezuka, Arsha; Egami, Eiichi; Oguri, Masamune; Suyu, Sherry H.; Sonnenfeld, Alessandro; Higuchi, Ryo; Komiyama, Yutaka; Miyazaki, Satoshi; Onoue, Masafusa; Oyamada, Shuri; Utsumi, Yousuke

    2016-08-01

    We report the serendipitous discovery of HSC J142449-005322, a double source plane lens system in the Hyper Suprime-Cam Subaru Strategic Program. We dub the system Eye of Horus. The lens galaxy is a very massive early-type galaxy with stellar mass of ˜ 7× {10}11 {M}⊙ located at {z}{{L}}=0.795. The system exhibits two arcs/rings with clearly different colors, including several knots. We have performed spectroscopic follow-up observations of the system with FIRE on Magellan. The outer ring is confirmed at {z}{{S}2}=1.988 with multiple emission lines, while the inner arc and counterimage is confirmed at {z}{{S}1}=1.302. This makes it the first double source plane system with spectroscopic redshifts of both sources. Interestingly, redshifts of two of the knots embedded in the outer ring are found to be offset by {{Δ }}z=0.002 from the other knots, suggesting that the outer ring consists of at least two distinct components in the source plane. We perform lens modeling with two independent codes and successfully reproduce the main features of the system. However, two of the lensed sources separated by ˜0.7 arcsec cannot be reproduced by a smooth potential, and the addition of substructure to the lens potential is required to reproduce them. Higher-resolution imaging of the system will help decipher the origin of this lensing feature and potentially detect the substructure.

  2. A Spectroscopically Confirmed Double Source Plane Lens System in the Hyper Suprime-Cam Subaru Strategic Program

    NASA Astrophysics Data System (ADS)

    Tanaka, Masayuki; Wong, Kenneth C.; More, Anupreeta; Dezuka, Arsha; Egami, Eiichi; Oguri, Masamune; Suyu, Sherry H.; Sonnenfeld, Alessandro; Higuchi, Ryo; Komiyama, Yutaka; Miyazaki, Satoshi; Onoue, Masafusa; Oyamada, Shuri; Utsumi, Yousuke

    2016-08-01

    We report the serendipitous discovery of HSC J142449‑005322, a double source plane lens system in the Hyper Suprime-Cam Subaru Strategic Program. We dub the system Eye of Horus. The lens galaxy is a very massive early-type galaxy with stellar mass of ˜ 7× {10}11 {M}ȯ located at {z}{{L}}=0.795. The system exhibits two arcs/rings with clearly different colors, including several knots. We have performed spectroscopic follow-up observations of the system with FIRE on Magellan. The outer ring is confirmed at {z}{{S}2}=1.988 with multiple emission lines, while the inner arc and counterimage is confirmed at {z}{{S}1}=1.302. This makes it the first double source plane system with spectroscopic redshifts of both sources. Interestingly, redshifts of two of the knots embedded in the outer ring are found to be offset by {{Δ }}z=0.002 from the other knots, suggesting that the outer ring consists of at least two distinct components in the source plane. We perform lens modeling with two independent codes and successfully reproduce the main features of the system. However, two of the lensed sources separated by ˜0.7 arcsec cannot be reproduced by a smooth potential, and the addition of substructure to the lens potential is required to reproduce them. Higher-resolution imaging of the system will help decipher the origin of this lensing feature and potentially detect the substructure.

  3. Teaching lens, optical systems, and opto-mechanical systems design at the Irvine Center for Applied Competitive Technologies (CACT)

    NASA Astrophysics Data System (ADS)

    Doushkina, Valentina V.; Silberman, Donn M.

    2007-09-01

    For well over a decade, the Laser Electro-Optics Technology (LET) program has been teaching introductory laser and optics classes at Irvine Valley College (IVC). At the beginning of the telecom boom, the Irvine CACT was established to teach optics fabrication to support the many optics fabrication businesses in Southern California. In the past few years, these two programs have merged - with some help from the Optics Institute of Southern California (OISC) - and grown under the newly established Advanced Technology and Education Park (ATEP). IVC and ATEP are both operated by the South Orange County Community College District (SOCCCD). This year a new program of three courses was established to teach, in sequence, lens, optical systems and optomechanical systems design. This paper reviews the reasons for establishing these courses and their content, the students' motivations for taking them and their employers' incentives for encouraging the students.

  4. Airframe-propulsion system aerodynamic interference predictions at high transonic Mach numbers including off-design engine airflow effects

    NASA Technical Reports Server (NTRS)

    Kulfan, R. M.; Sigalla, A.

    1981-01-01

    The transonic speed regime for airplanes at conditions where inlet spillage takes place is discussed. A wind tunnel test program to evaluate aerodynamic performance penalties associated with propulsion system installation and operation at subsonic through low supersonic speeds was conducted. The accuracy of analytic methods for predicting transonic engine airframe interference effects was assessed. Study variables included Mach number, angle of attack, relative nacelle location, and nacelle mass flow ratio. Results include test theory comparisons of forces as well as induced pressure fields. Prediction capability of induced shock wave strength and locations is assessed. It was found that large interference forces due to engine location and flow spillage occur at transonic speeds, that theory explains these effects; and that theory can predict quantitatively these effects.

  5. Miniature hybrid optical imaging lens

    DOEpatents

    Sitter, D.N. Jr.; Simpson, M.L.

    1997-10-21

    A miniature lens system that corrects for imaging and chromatic aberrations is disclosed, the lens system being fabricated from primarily commercially-available components. A first element at the input to a lens housing is an aperture stop. A second optical element is a refractive element with a diffractive element closely coupled to, or formed a part of, the rear surface of the refractive element. Spaced closely to the diffractive element is a baffle to limit the area of the image, and this is closely followed by a second refractive lens element to provide the final correction. The image, corrected for aberrations exits the last lens element to impinge upon a detector plane were is positioned any desired detector array. The diffractive element is fabricated according to an equation that includes, as variables, the design wavelength, the index of refraction and the radius from an optical axis of the lens system components. 2 figs.

  6. Miniature hybrid optical imaging lens

    DOEpatents

    Sitter, Jr., David N.; Simpson, Marc L.

    1997-01-01

    A miniature lens system that corrects for imaging and chromatic aberrations, the lens system being fabricated from primarily commercially-available components. A first element at the input to a lens housing is an aperture stop. A second optical element is a refractive element with a diffractive element closely coupled to, or formed a part of, the rear surface of the refractive element. Spaced closely to the diffractive element is a baffle to limit the area of the image, and this is closely followed by a second refractive lens element to provide the final correction. The image, corrected for aberrations exits the last lens element to impinge upon a detector plane were is positioned any desired detector array. The diffractive element is fabricated according to an equation that includes, as variables, the design wavelength, the index of refraction and the radius from an optical axis of the lens system components.

  7. Refraction limit of miniaturized optical systems: a ball-lens example.

    PubMed

    Kim, Myun-Sik; Scharf, Toralf; Mühlig, Stefan; Fruhnert, Martin; Rockstuhl, Carsten; Bitterli, Roland; Noell, Wilfried; Voelkel, Reinhard; Herzig, Hans Peter

    2016-04-01

    We study experimentally and theoretically the electromagnetic field in amplitude and phase behind ball-lenses across a wide range of diameters, ranging from a millimeter scale down to a micrometer. Based on the observation, we study the transition between the refraction and diffraction regime. The former regime is dominated by observables for which it is sufficient to use a ray-optical picture for an explanation, e.g., a cusp catastrophe and caustics. A wave-optical picture, i.e. Mie theory, is required to explain the features, e.g., photonic nanojets, in the latter regime. The vanishing of the cusp catastrophe and the emergence of the photonic nanojet is here understood as the refraction limit. Three different criteria are used to identify the limit: focal length, spot size, and amount of cross-polarization generated in the scattering process. We identify at a wavelength of 642 nm and while considering ordinary glass as the ball-lens material, a diameter of approximately 10 µm as the refraction limit. With our study, we shed new light on the means necessary to describe micro-optical system. This is useful when designing optical devices for imaging or illumination.

  8. Design of no blind area perimeter intrusion recognition system based on fisheye lens

    NASA Astrophysics Data System (ADS)

    Dai, Jun-jian; Han, Wen-bo

    2013-08-01

    The Perimeter intrusion recognition technology has slowly become an indispensable function in the intelligent video surveillance system. The existed always use the multiple video acquisition nodes to respectively control a monitoring area and each node alarm independently. However, the existed solutions are difficult to avoid the existence of monitoring blind area, and can't suitable for the perimeter environment with irregular outline, and at the same time, because of the too many nodes, it inevitably decreased the overall accuracy of intrusion recognition system and increased the cost of system. To avoid the above defects, this paper mainly talks about the following three aspects. Firstly, we used the fisheye lens as the optical system of video acquisition node, and it evidently enhances each node's information acquisition ability. And in this way, we just need to decorate a small amount of video acquisition node to get no blind area environmental information of the perimeter when against a larger monitoring situation. Secondly, due to the inexistence of blind area, the system will have enough video image information to generate the 360 degree panoramic image for monitoring environment, and finally the system server collected the wide-angle image information to splice into the panoramic video image. Finally, the system will use the panoramic image to complete the intrusion behavior recognition, thus we can effectively avoid the parallel computation in many nodes independently invasion of recognition, and this can greatly reduces the dependence for the multiple CPU operation platform and enhances the reliability of the system. The field test results show that, with the help of this paper's solution, the perimeter of the invasion of recognition system can effectively avoids the recognition of blind area. In the same recognition algorithm and same level delay premise, it greatly reduces the monitoring system server configuration requirements, especially for the

  9. The effects of a low-energy, high frequency liquid optic interface femtosecond laser system on lens capsulotomy

    PubMed Central

    Williams, Geraint P.; George, Ben L.; Wong, Yoke R.; Seah, Xin-Yi; Ang, Heng-Pei; Loke, Mun Kitt A.; Tay, Shian Chao; Mehta, Jod S.

    2016-01-01

    The introduction of femtosecond laser assisted cataract surgery (FLACS) is a paradigm changing approach in cataract surgery, the most commonly performed surgical procedure. FLACS has the potential to optimize the creation of an anterior lens capsulotomy, a critical step in accessing the cataractous lens. The merits of using a laser instead of a manual approach include a potentially more circular, consistent, and stronger aperture. In this study we demonstrated for the first time in both a porcine and human experimental setting that with a low energy, high repetition FLACS system, that a circular, smooth and strong capsulotomy was achievable. While there was no demonstrable difference in the resistance to rupture before or after the removal of the nucleus, larger capsulotomies had an increase in tensile strength. The LDV Z8 system appeared to create circular, rupture-resistant and smooth capsulotomies in both porcine and more importantly human globes. PMID:27090745

  10. The application of aerodynamic uncertainties in the design of the entry trajectory and flight control system of the space shuttle orbiter

    NASA Technical Reports Server (NTRS)

    Gamble, J. D.

    1983-01-01

    The process used in the application of aerodynamic uncertainties for the design and verification of the Space Shuttle Orbiter Entry Flight Control System is presented. The uncertainties were used to help set center of gravity, angle of attack and dynamic pressure lateral control divergence parameter as well as C sub n sub beta dynamic were instrumental in setting these placards.

  11. Lens auto-centering

    NASA Astrophysics Data System (ADS)

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève; Tremblay, Mathieu

    2015-09-01

    In a typical optical system, optical elements usually need to be precisely positioned and aligned to perform the correct optical function. This positioning and alignment involves securing the optical element in a holder or mount. Proper centering of an optical element with respect to the holder is a delicate operation that generally requires tight manufacturing tolerances or active alignment, resulting in costly optical assemblies. To optimize optical performance and minimize manufacturing cost, there is a need for a lens mounting method that could relax manufacturing tolerance, reduce assembly time and provide high centering accuracy. This paper presents a patent pending lens mounting method developed at INO that can be compared to the drop-in technique for its simplicity while providing the level of accuracy close to that achievable with techniques using a centering machine (usually < 5 μm). This innovative auto-centering method is based on the use of geometrical relationship between the lens diameter, the lens radius of curvature and the thread angle of the retaining ring. The autocentering principle and centering test results performed on real optical assemblies are presented. In addition to the low assembly time, high centering accuracy, and environmental robustness, the INO auto-centering method has the advantage of relaxing lens and barrel bore diameter tolerances as well as lens wedge tolerances. The use of this novel lens mounting method significantly reduces manufacturing and assembly costs for high performance optical systems. Large volume productions would especially benefit from this advancement in precision lens mounting, potentially providing a drastic cost reduction.

  12. Understanding pathways for scaling up health services through the lens of complex adaptive systems.

    PubMed

    Paina, Ligia; Peters, David H

    2012-08-01

    Despite increased prominence and funding of global health initiatives, efforts to scale up health services in developing countries are falling short of the expectations of the Millennium Development Goals. Arguing that the dominant assumptions for scaling up are inadequate, we propose that interpreting change in health systems through the lens of complex adaptive systems (CAS) provides better models of pathways for scaling up. Based on an understanding of CAS behaviours, we describe how phenomena such as path dependence, feedback loops, scale-free networks, emergent behaviour and phase transitions can uncover relevant lessons for the design and implementation of health policy and programmes in the context of scaling up health services. The implications include paying more attention to local context, incentives and institutions, as well as anticipating certain types of unintended consequences that can undermine scaling up efforts, and developing and implementing programmes that engage key actors through transparent use of data for ongoing problem-solving and adaptation. We propose that future efforts to scale up should adapt and apply the models and methodologies which have been used in other fields that study CAS, yet are underused in public health. This can help policy makers, planners, implementers and researchers to explore different and innovative approaches for reaching populations in need with effective, equitable and efficient health services. The old assumptions have led to disappointed expectations about how to scale up health services, and offer little insight on how to scale up effective interventions in the future. The alternative perspectives offered by CAS may better reflect the complex and changing nature of health systems, and create new opportunities for understanding and scaling up health services.

  13. X-shooter observations of the gravitational lens system CASSOWARY 5

    NASA Astrophysics Data System (ADS)

    Christensen, Lise; D'Odorico, Sandro; Pettini, Max; Belokurov, Vasily; Evans, N. Wyn; Kellogg, Melinda; Vernet, Joël

    2010-08-01

    We confirm an eighth gravitational lens system in the CAmbridge Sloan Survey Of Wide ARcs in the skY (CASSOWARY) catalogue. Exploratory observations with the X-shooter spectrograph on the Very Large Telescope of the European Southern Observatory show the system CASSOWARY 5 (CSWA5) to consist of at least three images of a blue star-forming galaxy at z = 1.0686, lensed by an apparent foreground group of red galaxies, one of which is at z = 0.3877. The lensed galaxy exhibits a rich spectrum with broad interstellar absorption lines and a wealth of nebular emission lines. Preliminary analysis of these features shows the galaxy to be young, with an age of ~25-50Myr. With a star formation rate of ~20Msolaryr-1, the galaxy has already assembled a stellar mass M* ~ 3 × 109Msolar and reached half-solar metallicity. Its blue spectral energy distribution and Balmer line ratios suggest negligible internal dust extinction. A more in-depth analysis of the properties of this system is currently hampered by the lack of a viable lensing model. However, it is already clear that CSWA5 shares many of its physical characteristics with the general population of UV-selected galaxies at redshifts z = 1-3, motivating further study of both the source and the foreground mass concentration responsible for the gravitational lensing. Based on public data from the X-shooter commissioning observations collected at the European Southern Observatory VLT/Melipal telescope, Paranal, Chile. E-mail: lise.christensen@ph.tum.de

  14. Understanding pathways for scaling up health services through the lens of complex adaptive systems.

    PubMed

    Paina, Ligia; Peters, David H

    2012-08-01

    Despite increased prominence and funding of global health initiatives, efforts to scale up health services in developing countries are falling short of the expectations of the Millennium Development Goals. Arguing that the dominant assumptions for scaling up are inadequate, we propose that interpreting change in health systems through the lens of complex adaptive systems (CAS) provides better models of pathways for scaling up. Based on an understanding of CAS behaviours, we describe how phenomena such as path dependence, feedback loops, scale-free networks, emergent behaviour and phase transitions can uncover relevant lessons for the design and implementation of health policy and programmes in the context of scaling up health services. The implications include paying more attention to local context, incentives and institutions, as well as anticipating certain types of unintended consequences that can undermine scaling up efforts, and developing and implementing programmes that engage key actors through transparent use of data for ongoing problem-solving and adaptation. We propose that future efforts to scale up should adapt and apply the models and methodologies which have been used in other fields that study CAS, yet are underused in public health. This can help policy makers, planners, implementers and researchers to explore different and innovative approaches for reaching populations in need with effective, equitable and efficient health services. The old assumptions have led to disappointed expectations about how to scale up health services, and offer little insight on how to scale up effective interventions in the future. The alternative perspectives offered by CAS may better reflect the complex and changing nature of health systems, and create new opportunities for understanding and scaling up health services. PMID:21821667

  15. Enhancement of the optical performances for the LED backlight systems with a novel lens cap

    NASA Astrophysics Data System (ADS)

    Chang, Jee-Gong; Liao, Charles Lun-De; Hwang, Chi-Chuan

    2006-08-01

    A novel dual-cone-shaped side-emitting lens cap for High Brightness Light Emitting Diodes (HB-LEDs) is proposed for improving brightness and high uniformity of the direct LED acklight Units (BLUs) for large area LCD-TVs. Combining the designed lens cap with red, green and blue (RGB) chips on a Metal Core Printed Circuit Board (MCPCB), the LED module with the proposed cap is able to provide a compact white light source with unique features such as instant color variability and lower power usage, etc. The dual-cone-shaped of the proposed lens cap is designed to emitting most of the light rays to the sides, only a small portion of light upward along the optical axis of the lens, providing a uniform luminance distribution and the high brightness on the backlight. In addition, a small, half-circle eflective surface is designed and upon the proposed LED module about 10mm, the surfaces of which are attached with reflective films to increase the level of light mixing in the larger, global reflector optical box. With the structure of the LED module well designed, the LED backlight Module would design for the large area LCD-TV using the fewer number of LEDs and also have low power consumption. The results indeed identify the attributes of the BLU, which make it possible to achieve excellent backlight performance using a direct illumination approach from the light source of "Dual-Cone-Shaped Side-Emitting Lens Cap of LEDs".

  16. High-precision optomechanical lens system for space applications assembled by a local soldering technique

    NASA Astrophysics Data System (ADS)

    Pleguezuelo, Pol Ribes; Koechlin, Charlie; Hornaff, Marcel; Kamm, Andreas; Beckert, Erik; Fiault, Guillaume; Eberhardt, Ramona; Tünnermann, Andreas

    2016-06-01

    Soldering using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glass, ceramics, and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard using specifications and requirements found for the optical beam expander for the European Space Agency EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands of handling high mechanical and thermal loads without losing the optical performance. Finally, a high-precision optomechanical lens mount has been assembled with minimal localized stress (<1 MPa) showing outstanding performance in terms of wave-front error and beam depolarization ratio before and after environmental tests.

  17. Advanced gradient-index lens design tools to maximize system performance and reduce SWaP

    NASA Astrophysics Data System (ADS)

    Campbell, Sawyer D.; Nagar, Jogender; Brocker, Donovan E.; Easum, John A.; Turpin, Jeremiah P.; Werner, Douglas H.

    2016-05-01

    GRadient-INdex (GRIN) lenses have long been of interest due to their potential for providing levels of performance unachievable with traditional homogeneous lenses. While historically limited by a lack of suitable materials, rapid advancements in manufacturing techniques, including 3D printing, have recently kindled a renewed interest in GRIN optics. Further increasing the desire for GRIN devices has been the advent of Transformation Optics (TO), which provides the mathematical framework for representing the behavior of electromagnetic radiation in a given geometry by "transforming" it to an alternative, usually more desirable, geometry through an appropriate mapping of the constituent material parameters. Using TO, aspherical lenses can be transformed to simpler spherical and flat geometries or even rotationally-asymmetric shapes which result in true 3D GRIN profiles. Meanwhile, there is a critical lack of suitable design tools which can effectively evaluate the optical wave propagation through 3D GRIN profiles produced by TO. Current modeling software packages for optical lens systems also lack advanced multi-objective global optimization capability which allows the user to explicitly view the trade-offs between all design objectives such as focus quality, FOV, ▵nand focal drift due to chromatic aberrations. When coupled with advanced design methodologies such as TO, wavefront matching (WFM), and analytical achromatic GRIN theory, these tools provide a powerful framework for maximizing SWaP (Size, Weight and Power) reduction in GRIN-enabled optical systems. We provide an overview of our advanced GRIN design tools and examples which minimize the presence of mono- and polychromatic aberrations in the context of reducing SWaP.

  18. Validation of a pair of computer codes for estimation and optimization of subsonic aerodynamic performance of simple hinged-flap systems for thin swept wings

    NASA Technical Reports Server (NTRS)

    Carlson, Harry W.; Darden, Christine M.

    1988-01-01

    Extensive correlations of computer code results with experimental data are employed to illustrate the use of linearized theory attached flow methods for the estimation and optimization of the aerodynamic performance of simple hinged flap systems. Use of attached flow methods is based on the premise that high levels of aerodynamic efficiency require a flow that is as nearly attached as circumstances permit. A variety of swept wing configurations are considered ranging from fighters to supersonic transports, all with leading- and trailing-edge flaps for enhancement of subsonic aerodynamic efficiency. The results indicate that linearized theory attached flow computer code methods provide a rational basis for the estimation and optimization of flap system aerodynamic performance at subsonic speeds. The analysis also indicates that vortex flap design is not an opposing approach but is closely related to attached flow design concepts. The successful vortex flap design actually suppresses the formation of detached vortices to produce a small vortex which is restricted almost entirely to the leading edge flap itself.

  19. Deep optical imaging and spectroscopy of the lens system SDSS J1339+1310

    NASA Astrophysics Data System (ADS)

    Shalyapin, V. N.; Goicoechea, L. J.

    2014-08-01

    We present deep I-band imaging (NOT-ALFOSC) and spectroscopic (GTC-OSIRIS) observations of the gravitational lens system SDSS J1339+1310. This consists of two images of a lensed quasar, A and B, and a lensing galaxy G between the two quasar images. Our observations led to the following main results: (1) We obtained new accurate positions for B and G (relative to A), as well as structure parameters for the light distribution of G. The new position angle for G is separated by ~50° from the previously determined value. (2) The spectrum of G is typical for early-type galaxies, and we measured its redshift (0.609 ± 0.001) for the first time. (3) We determined the flux ratio B/A for the cores of the emission lines in the two quasar spectra. They were used to constrain the macrolens flux ratio MBA and dust extinction parameters. (4) The continuum flux ratio was appropriately corrected to obtain the microlensing magnification ratio of the continuum μBA. This μBA indicates that B is amplified (relative to A) by a factor of about 3-5, with larger amplifications at shorter wavelengths. The observed microlensing chromaticity coincides with a sharp drop in the r-band flux of B. (5) We reconstructed the lensing mass from the new observational constraints on the relative astrometry, MBA and the luminous structure of G. We also used the redshift of G to predict the time delay between quasar images (43 ± 5 d, A is leading).

  20. THE OPTIMAL GRAVITATIONAL LENS TELESCOPE

    SciTech Connect

    Surdej, J.; Hanot, C.; Sadibekova, T.; Delacroix, C.; Habraken, S.; Coleman, P.; Dominik, M.; Le Coroller, H.; Mawet, D.; Quintana, H.; Sluse, D.

    2010-05-15

    Given an observed gravitational lens mirage produced by a foreground deflector (cf. galaxy, quasar, cluster, ...), it is possible via numerical lens inversion to retrieve the real source image, taking full advantage of the magnifying power of the cosmic lens. This has been achieved in the past for several remarkable gravitational lens systems. Instead, we propose here to invert an observed multiply imaged source directly at the telescope using an ad hoc optical instrument which is described in the present paper. Compared to the previous method, this should allow one to detect fainter source features as well as to use such an optimal gravitational lens telescope to explore even fainter objects located behind and near the lens. Laboratory and numerical experiments illustrate this new approach.

  1. In-Flight Aeroelastic Stability of the Thermal Protection System on the NASA HIAD, Part II: Nonlinear Theory and Extended Aerodynamics

    NASA Technical Reports Server (NTRS)

    Goldman, Benjamin D.; Dowell, Earl H.; Scott, Robert C.

    2015-01-01

    Conical shell theory and a supersonic potential flow aerodynamic theory are used to study the nonlinear pressure buckling and aeroelastic limit cycle behavior of the thermal protection system for NASA's Hypersonic Inflatable Aerodynamic Decelerator. The structural model of the thermal protection system consists of an orthotropic conical shell of the Donnell type, resting on several circumferential elastic supports. Classical Piston Theory is used initially for the aerodynamic pressure, but was found to be insufficient at low supersonic Mach numbers. Transform methods are applied to the convected wave equation for potential flow, and a time-dependent aerodynamic pressure correction factor is obtained. The Lagrangian of the shell system is formulated in terms of the generalized coordinates for all displacements and the Rayleigh-Ritz method is used to derive the governing differential-algebraic equations of motion. Aeroelastic limit cycle oscillations and buckling deformations are calculated in the time domain using a Runge-Kutta method in MATLAB. Three conical shell geometries were considered in the present analysis: a 3-meter diameter 70 deg. cone, a 3.7-meter 70 deg. cone, and a 6-meter diameter 70 deg. cone. The 6-meter configuration was loaded statically and the results were compared with an experimental load test of a 6-meter HIAD. Though agreement between theoretical and experimental strains was poor, the circumferential wrinkling phenomena observed during the experiments was captured by the theory and axial deformations were qualitatively similar in shape. With Piston Theory aerodynamics, the nonlinear flutter dynamic pressures of the 3-meter configuration were in agreement with the values calculated using linear theory, and the limit cycle amplitudes were generally on the order of the shell thickness. The effect of axial tension was studied for this configuration, and increasing tension was found to decrease the limit cycle amplitudes when the circumferential

  2. Auto-measuring system of aero-camera lens focus using linear CCD

    NASA Astrophysics Data System (ADS)

    Zhang, Yu-ye; Zhao, Yu-liang; Wang, Shu-juan

    2014-09-01

    The automatic and accurate focal length measurement of aviation camera lens is of great significance and practical value. The traditional measurement method depends on the human eye to read the scribed line on the focal plane of parallel light pipe by means of reading microscope. The method is of low efficiency and the measuring results are influenced by artificial factors easily. Our method used linear array solid-state image sensor instead of reading microscope to transfer the imaging size of specific object to be electrical signal pulse width, and used computer to measure the focal length automatically. In the process of measurement, the lens to be tested placed in front of the object lens of parallel light tube. A couple of scribed line on the surface of the parallel light pipe's focal plane were imaging on the focal plane of the lens to be tested. Placed the linear CCD drive circuit on the image plane, the linear CCD can convert the light intensity distribution of one dimension signal into time series of electrical signals. After converting, a path of electrical signals is directly brought to the video monitor by image acquisition card for optical path adjustment and focusing. The other path of electrical signals is processed to obtain the pulse width corresponding to the scribed line by electrical circuit. The computer processed the pulse width and output focal length measurement result. Practical measurement results showed that the relative error was about 0.10%, which was in good agreement with the theory.

  3. Study on the effective method to reduce the lens calibre of the un-cooled IR thermal imaging systems

    NASA Astrophysics Data System (ADS)

    Dong, Li-quan; Jin, Wei-qi; Gao, Bo; Zhou, Xiao-xiao

    2007-09-01

    During the development of the research and the manufacture technical, the Infrared thermal imaging systems has developments advance rapidly. And its applied field has going deep into the space technology, industry, agriculture, medical, traffic and other fields from the national defense and military appliance. Especially in the application of the military, it has come into being a specialty IR System Engineering field. But in many important applications, the lens calibre of the IR thermal imaging systems often be made very large to advance the SNR of the systems. This increased the weight and the research cost of the whole system very much. Many research indicated that the main factor to affect the image quality of the IR systems is the fixed pattern noise (FPN) or spatial non-uniformity under the actual technical and manufacture level. If we using the effective dynamic self-adaptive non-uniformity correction algorithms for the IR system, and use the image enhancement technology simultaneity. We can advance the imaging quality greatly. With this plan, the correction image we got with large F number can receive the level that uncorrected image with 1 or 2 smaller F number. It means the lens calibre of the system will be reduced effectively. And the weight, the cubage and the research cost of the system will be reduced greatly. It will have most important value in the applied of the actual engineering.

  4. 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.

  5. Field comparison of an eddy accumulation and an aerodynamic-gradient system for measuring pesticide volatilization fluxes

    USGS Publications Warehouse

    Majewski, M.; Desjardina, R.; Rochette, P.; Pattey, E.; Selber, J.; Glotfelty, D.

    1993-01-01

    The field experiment reported here applied the relaxed eddy accumulation (REA) technique to the measurement of triallate (TA) and trifluralin (TF) volatilization from fallow soil. A critical analysis of the REA system used in this experiment is done, and the fluxes are compared to those obtained by the aerodynamic-gradient (AG) technique. The measured cumulative volatilization losses, corrected for the effective upwind source area (footprint), for the AG system were higher than with the REA system. The differences between the methods over the first 5 days of the experiment were 27 and 13% for TA and TF, respectively. A mass balance based on the amount of parent compounds volatilized from soil during the first 5 days of the experiment showed a 110 and 70% and a 79 and 61% accountability for triallate and trifluralin by the AG and REA methods, respectively. These results also show that the non-footprint-corrected AG flux values underestimated the volatilization flux by approximately 16%. The footprint correction model used in this experiment does not presently have the capability of accounting for changes in atmospheric stability. However, these values still provide an indication of the most likely upwind area affecting the evaporative flux estimations. The soil half-lives for triallate and trifluralin were 9.8 and 7.0 days, respectively. ?? 1992 American Chemical Society.

  6. 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.

  7. 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.

  8. An aerodynamic investigation of two 1.83-meter-diameter fan systems designed to drive a subsonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Page, V. R.; Eckert, W. T.; Mort, K. W.

    1977-01-01

    An experimental, aerodynamic investigation was made of two 1.83 m diameter fan systems which are being considered for the repowered drive section of the 40- by 80-foot wind tunnel at NASA Ames Research Center. One system was low speed, the other was high speed. The low speed fan was tested at various stagger angles from 32.9 deg to 62.9 deg. At a fan blade stagger angle of 40.8 deg and operating at a tip speed of 1155 m/sec, the low speed fan developed 207.3 m of head. The high speed fan had a design blade stagger angle of 56.2 deg and was tested at this stagger angle only. The high speed fan operating at 191.5 m/sec developed 207.3 m of head. Radial distributions of static pressure coefficients, total pressure coefficients, and angles of swirl are presented. Radial surveys were conducted at four azimuth locations in front of the fan, and repeated downstream of the fan. Data were taken for various flow control devices and for two inlet contraction lengths.

  9. Bifurcations in unsteady aerodynamics

    NASA Technical Reports Server (NTRS)

    Tobak, M.; Unal, A.

    1986-01-01

    Nonlinear algebraic functional expansions are used to create a form for the unsteady aerodynamic response that is consistent with solutions of the time dependent Navier-Stokes equations. An enumeration of means of invalidating Frechet differentiability of the aerodynamic response, one of which is aerodynamic bifurcation, is proposed as a way of classifying steady and unsteady aerodynamic phenomena that are important in flight dynamics applications. Accomodating bifurcation phenomena involving time dependent equilibrium states within a mathematical model of the aerodynamic response raises an issue of memory effects that becomes more important with each successive bifurcation.

  10. About using wide field lens optics for Space Surveillance Systems in Odessa Astronomical observatory (Ukraine)

    NASA Astrophysics Data System (ADS)

    Sukhov, P. P.; Volkoff, S. K.; Karpenko, G. F.; Titenko, V. V.; Yamnitsky, V. A.; Tkachenko, A. A.

    2007-08-01

    On base results of the observations in Odessa astronomical observatory, is shown obvious fact. The possibility of the using domestic wide field lens optics for monitoring high orbital artificial Earth satellite objects for the calculations elements of orbits. With wide field lens optics "Tair-19 5003", limited magnitude consist 15m.5 per 10 seconds of the accumulation, average square-error (ASE) of the measurements of the coordinates slowly move GSS consist not more than 2 arcsec. Beside 90% measurements has ASE not more 1 arcsec. At surveillance of the area of the equator by width 5° areas 500 deg2 are discovered all 40 active "standing" GSS, 12 passive GSS and 2 high elliptical orbital satellites (HEO). Is shown perspective possibility of the use WFO for monitoring LEO height before of 2 000 km. 90% of 39 object LEO fixed in mode "beam-park" (the still telescope) in current 1 hour, surelay are identified using catalog NORAD.

  11. The Optical Design of a System using a Fresnel Lens that Gathers Light for a Solar Concentrator and that Feeds into Solar Alignment Optics

    NASA Technical Reports Server (NTRS)

    Wilkerson, Gary W.; Huegele, Vinson

    1998-01-01

    The Marshall Space Flight Center (MSFC) has been developing a space deployable, lightweight membrane concentrator to focus solar energy into a solar furnace while remaining aligned to the sun. For an inner surface, this furnace has a cylindrical heat exchanger cavity coaligned to the optical axis; the furnace warms gas to propel the spacecraft. The membrane concentrator is a 1727 mm (68.00 in.) diameter, F/1.7 Fresnel lens. This large membrane is made from polyimide and is 0.076 mm (0.0030 in.) thick; it has the Fresnel grooves cast into it. The solar concentrator system has a super fast paraboloid reflector near the lens focus and immediately adjacent to the cylindrical exchanger cavity. The paraboloid collects the wide bandwidth and some of the solar energy scattered by the Fresnel lens. Finally, the paraboloid feeds the light into the cylinder. The Fresnel lens also possesses a narrow annular zone that focuses a reference beam toward four detectors that keep the optical system aligned to the sun; thus, occurs a refracting lens that focuses two places! The result can be summarized as a composite Fresnel lens for solar concentration and alignment.

  12. 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.

  13. Aerodynamic design and analysis system for supersonic aircraft. Part 2: User's manual

    NASA Technical Reports Server (NTRS)

    Middleton, W. D.; Lundry, J. L.; Coleman, R. G.

    1975-01-01

    An integrated system of computer programs for supersonic configurations is described. An explanation of system usage, the input definitions, and example output are included. For Part 1, see N75-18185; for Part 3, see N75-18186.

  14. 14 CFR 25.445 - Auxiliary aerodynamic surfaces.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Auxiliary aerodynamic surfaces. 25.445... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.445 Auxiliary aerodynamic surfaces. (a) When significant, the aerodynamic influence...

  15. Long-term monitoring, time delay, and microlensing in the gravitational lens system Q0142-100

    SciTech Connect

    Oscoz, A.; Serra-Ricart, M.; Mediavilla, E.

    2013-12-20

    We present 12 yr of monitoring of the gravitational lens Q0142-100 from the Teide Observatory. The data, taken from 1999 to 2010, comprise 105 observing nights with the IAC80 Telescope. The application of the δ{sup 2} method to the dataset leads to a value for the time delay between both components of the system of 72 ± 22 days (68% confidence level), consistent within uncertainties with the most recent results. With this value in mind a possible microlensing event is detected in Q0142-100.

  16. Subsonic and supersonic static aerodynamic characteristics of a family of bulbous base cones measured with a magnetic suspension and balance system

    NASA Technical Reports Server (NTRS)

    Vlajinac, M.; Stephens, T.; Gilliam, G.; Pertsas, N.

    1972-01-01

    Results of subsonic and supersonic wind-tunnel tests with a magnetic balance and suspension system on a family of bulbous based cone configurations are presented. At subsonic speeds the base flow and separation characteristics of these configurations is shown to have a pronounced effect on the static data. Results obtained with the presence of a dummy sting are compared with support interference free data. Support interference is shown to have a substantial effect on the measured aerodynamic coefficient.

  17. Computational Aerodynamic Simulations of an 840 ft/sec Tip Speed Advanced Ducted Propulsor Fan System Model for Acoustic Methods Assessment and Development

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2014-01-01

    Computational Aerodynamic simulations of an 840 ft/sec tip speed, Advanced Ducted Propulsor fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, lownoise research fan/nacelle model that has undergone extensive experimental testing in the 9- by 15- foot Low Speed Wind Tunnel at the NASA Glenn Research Center, resulting in quality, detailed aerodynamic and acoustic measurement data. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating conditions simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, excluding a long core duct section downstream of the core inlet guide vane. As a result, only fan rotational speed and system bypass ratio, set by specifying static pressure downstream of the core inlet guide vane row, were adjusted in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. The computed blade row flow fields for all five fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the computed flow fields reveals no excessive boundary layer separations or related secondary-flow problems. A few spanwise comparisons between

  18. A program to evaluate a control system based on feedback of aerodynamic pressure differentials, part 1

    NASA Technical Reports Server (NTRS)

    Hrabak, R. R.; Levy, D. W.; Finn, P.; Roskam, J.

    1981-01-01

    The use of pressure differentials in a flight control system was evaluated. The pressure profile around the test surface was determined using two techniques: (1) windtunnel data (actual); and (2) NASA/Langley Single Element Airfoil Computer Program (theoretical). The system designed to evaluate the concept of using pressure differentials is composed of a sensor drive and power amplifiers, actuator, position potentiometer, and a control surface. The characteristics (both desired and actual) of the system and each individual component were analyzed. The desired characteristics of the system as a whole are given. The flight control system developed, the testing procedures and data reduction methods used, and theoretical frequency response analysis are described.

  19. New merit values for lens performance.

    NASA Astrophysics Data System (ADS)

    Nakagawa, J.

    1995-08-01

    New merit values for lens performance m=Σ(Qh)2 and m¯=Σ(Qh¯)2 were introduced, where Q is Abbe's invariant, h is paraxial ray height and the bar indicates principal ray. The studies showed that m and m¯ are useful for the evaluation of potentialities of lens systems and for the optimization of lens designs.

  20. Kiloparsec Mass/Light Offsets in the Galaxy Pair-Lyα Emitter Lens System SDSS J1011+0143

    NASA Astrophysics Data System (ADS)

    Shu, Yiping; Bolton, Adam S.; Moustakas, Leonidas A.; Stern, Daniel; Dey, Arjun; Brownstein, Joel R.; Burles, Scott; Spinrad, Hyron

    2016-03-01

    We report the discovery of significant mass/light offsets in the strong gravitational lensing system SDSS J1011+0143. We use the high-resolution Hubble Space Telescope (HST) F555W- and F814W-band imaging and Sloan Digital Sky Survey (SDSS) spectroscopy of this system, which consists of a close galaxy pair with a projected separation of ≈ 4.2 {{kpc}} at zlens ˜ 0.331 lensing an Lyα emitter (LAE) at zsource = 2.701. Comparisons between the mass peaks inferred from lens models and light peaks from HST imaging data reveal significant spatial mass/light offsets as large as 1.72 ± 0.24 ± 0.34 kpc in both filter bands. Such large mass/light offsets, not seen in isolated field lens galaxies and relaxed galaxy groups, may be related to the interactions between the two lens galaxies. The detected mass/light offsets can potentially serve as an important test for the self-interacting dark matter model. However, other mechanisms such as dynamical friction on spatially differently distributed dark matter and stars could produce similar offsets. Detailed hydrodynamical simulations of galaxy-galaxy interactions with self-interacting dark matter could accurately quantify the effects of different mechanisms. The background LAE is found to contain three distinct star-forming knots with characteristic sizes from 116 to 438 pc. It highlights the power of strong gravitational lensing in probing the otherwise too faint and unresolved structures of distance objects below subkiloparsec or even 100 pc scales through its magnification effect. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with program #10831.

  1. 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.

  2. Aerodynamic Stabilization of Flexible Optical Disk with Triangularly Arranged Stabilizer System

    NASA Astrophysics Data System (ADS)

    Aman, Yasutomo; Onagi, Nobuaki; Murata, Shozo; Uchida, Keisuke

    2005-05-01

    We have developed a flexible optical disk (FOD) system comprising a flexible disk and stabilizer, which can achieve a small axial runout of the disk through simplified stabilizer control. The approach adopts a new stabilizer system made up of triangularly arranged stabilizers (TASs), which consists of one main stabilizer (MS) that stabilizes the pickup focus area on the disk and two auxiliary stabilizers (ASs) that control the balancing conditions around the MS. We experimentally demonstrated that the TAS system could effectively stabilize a flexible disk even under conditions with no active stabilizer adjustments, such as axial position control and tilt control, which could not be eliminated in our previous single-stabilizer system. The suppressed axial runout without active adjustments was sufficiently small of less than 5 μm at linear velocities from 5.7 to 13.0 m/s up to double the speed of Blu-ray disk system. The results indicated that the FOD system with the TASs, which is easily operated, could be implemented in high-density optical disk systems with a high numerical-aperture (NA) pickup.

  3. Metamaterial lens design

    NASA Astrophysics Data System (ADS)

    Shepard, Ralph Hamilton, III

    Developments in nanotechnology and material science have produced optical materials with astonishing properties. Theory and experimentation have demonstrated that, among other properties, the law of refraction is reversed at an interface between a naturally occurring material and these so-called metamaterials. As the technology advances metamaterials have the potential to vastly impact the field of optical science. In this study we provide a foundation for future work in the area of geometric optics and lens design with metamaterials. The concept of negative refraction is extended to derive a comprehensive set of first-order imaging principles as well as an exhaustive aberration theory to 4th order. Results demonstrate congruence with the classical theory; however, negative refraction introduces a host of novel properties. In terms of aberration theory, metamaterials present the lens designer with increased flexibility. A singlet can be bent to produce either positive or negative spherical aberration (regardless of its focal length), its contribution to coma can become independent of its conjugate factor, and its field curvature takes on the opposite sign of its focal power. This is shown to be advantageous in some designs such as a finite conjugate relay lens; however, in a wider field of view landscape lens we demonstrate a metamaterial's aberration properties may be detrimental. This study presents the first comprehensive investigation of metamaterial lenses using industry standard lens design software. A formal design study evaluates the performance of doublet and triplet lenses operating at F/5 with a 100 mm focal length, a 20° half field of view, and specific geometric constraints. Computer aided optimization and performance evaluation provide experimental controls to remove designer-induced bias from the results. Positive-index lenses provide benchmarks for comparison to metamaterial systems subjected to identical design constraints. We find that

  4. 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.

  5. Distortion correction for microscopic fringe projection system with Scheimpflug telecentric lens.

    PubMed

    Peng, Junzheng; Wang, Meng; Deng, Dingnan; Liu, Xiaoli; Yin, Yongkai; Peng, Xiang

    2015-12-01

    To increase the measurement range of 3D microscopy, Scheimpflug adjustment, in which the imaging plane is tilted with respect to the telecentric lens plane, is often employed. However, the inclined imaging plane will introduce certain distortion to the captured image, which further affects the accuracy of the 3D reconstruction result. In this paper, a distortion model was derived based on the geometric optics theory. With it, the imaging distortion caused by the Scheimpflug condition can be effectively corrected. Experimental results will be presented to demonstrate the feasibility and validity of the proposed method. PMID:26836660

  6. Fresnel Lens Characterization for Potential Use in an Unpiloted Atmospheric Vehicle DIAL Receiver System

    NASA Technical Reports Server (NTRS)

    Fastig, Shlomo; Deoung, Russell J.

    1998-01-01

    Acrylic plastic Fresnel lenses are very light and can have large diameters. Such lenses could be used in lidar telescope receivers if the focal spot is not too large or distorted. This research effort characterizes the focal spot diameter produced by a Fresnel lens with a diameter of 30.5 cm (12 in.). It was found that the focal spot diameter varied from 1.2 mm at 750 nm to 1.6 mm at 910 nm. The focal spot was irregular and not easily described by a Gaussian profile.

  7. System maintenance manual for master modeling of aerodynamic surfaces by three-dimensional explicit representation

    NASA Technical Reports Server (NTRS)

    Gibson, A. F.

    1983-01-01

    A system of computer programs has been developed to model general three-dimensional surfaces. Surfaces are modeled as sets of parametric bicubic patches. There are also capabilities to transform coordinate to compute mesh/surface intersection normals, and to format input data for a transonic potential flow analysis. A graphical display of surface models and intersection normals is available. There are additional capabilities to regulate point spacing on input curves and to compute surface intersection curves. Internal details of the implementation of this system are explained, and maintenance procedures are specified.

  8. Aerodynamic surface distension system for high angle of attack forebody vortex control

    NASA Technical Reports Server (NTRS)

    Zell, Peter T. (Inventor)

    1994-01-01

    A deployable system is introduced for assisting flight control under certain flight conditions, such as at high angles of attack, whereby two inflatable membranes are located on the forebody portion of an aircraft on opposite sides thereof. The members form control surfaces for effecting lateral control forces if one is inflated and longitudinal control forces if both are inflated.

  9. Aerodynamic design and analysis system for supersonic aircraft. Part 3: Computer program description

    NASA Technical Reports Server (NTRS)

    Middleton, W. D.; Lundry, J. L.; Coleman, R. G.

    1975-01-01

    The computer program for the design and analysis of supersonic aircraft configurations is presented. The schematics of the program structure are provided. The individual overlays and subroutines are described. The system is useful in determining surface pressures and supersonic area rule concepts.

  10. Golf Aerodynamics

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A former Martin Marietta Manned Space Systems engineer, Robert T. Thurman went from analyzing airloads on the Space Shuttle External Tank to analyzing airloads on golf balls for Wilson Sporting Goods Company. Using his NASA know-how, Thurman designed the Ultra 500 golf ball, which has three different-sized dimples in 60 triangular faces (instead of the usual 20) formed by a series of intersecting "parting" lines. This balances the asymmetry caused by the molding line in all golf balls. According to Wilson, the ball sustains initial velocity longer and produces the most stable ball flight for "unmatched" accuracy and distance.

  11. Aerodynamics of the Large-Volume, Flow-Through Detector System. Final report

    SciTech Connect

    Reed, H.; Saric, W.; Laananen, D.; Martinez, C.; Carrillo, R.; Myers, J.; Clevenger, D.

    1996-03-01

    The Large-Volume Flow-Through Detector System (LVFTDS) was designed to monitor alpha radiation from Pu, U, and Am in mixed-waste incinerator offgases; however, it can be adapted to other important monitoring uses that span a number of potential markets, including site remediation, indoor air quality, radon testing, and mine shaft monitoring. Goal of this effort was to provide mechanical design information for installation of LVFTDS in an incinerator, with emphasis on ability to withstand the high temperatures and high flow rates expected. The work was successfully carried out in three stages: calculation of pressure drop through the system, materials testing to determine surrogate materials for wind-tunnel testing, and wind-tunnel testing of an actual configuration.

  12. Modeling transonic aerodynamic response using nonlinear systems theory for use with modern control theory

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.

    1993-01-01

    The presentation begins with a brief description of the motivation and approach that has been taken for this research. This will be followed by a description of the Volterra Theory of Nonlinear Systems and the CAP-TSD code which is an aeroelastic, transonic CFD (Computational Fluid Dynamics) code. The application of the Volterra theory to a CFD model and, more specifically, to a CAP-TSD model of a rectangular wing with a NACA 0012 airfoil section will be presented.

  13. Pediatric genetic disorders of lens.

    PubMed

    Nihalani, Bharti R

    2014-12-01

    Pediatric genetic disorders of lens include various cataractous and non-cataractous anomalies. The purpose of this review is to help determine the genetic cause based on the lens appearance, ocular and systemic associations. Children with bilateral cataracts require a comprehensive history, ophthalmic and systemic examination to guide further genetic evaluation. With advancements in genetics, it is possible to determine the genetic mutations and assess phenotype genotype correlation in different lens disorders. The genetic diagnosis helps the families to better understand the disorder and develop realistic expectations as to the course of their child's disorder. PMID:27625879

  14. Pediatric genetic disorders of lens

    PubMed Central

    Nihalani, Bharti R.

    2014-01-01

    Pediatric genetic disorders of lens include various cataractous and non-cataractous anomalies. The purpose of this review is to help determine the genetic cause based on the lens appearance, ocular and systemic associations. Children with bilateral cataracts require a comprehensive history, ophthalmic and systemic examination to guide further genetic evaluation. With advancements in genetics, it is possible to determine the genetic mutations and assess phenotype genotype correlation in different lens disorders. The genetic diagnosis helps the families to better understand the disorder and develop realistic expectations as to the course of their child's disorder.

  15. 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.

  16. In vivo human crystalline lens topography

    PubMed Central

    Ortiz, Sergio; Pérez-Merino, Pablo; Gambra, Enrique; de Castro, Alberto; Marcos, Susana

    2012-01-01

    Custom high-resolution high-speed anterior segment spectral domain optical coherence tomography (OCT) was used to characterize three-dimensionally (3-D) the human crystalline lens in vivo. The system was provided with custom algorithms for denoising and segmentation of the images, as well as for fan (scanning) and optical (refraction) distortion correction, to provide fully quantitative images of the anterior and posterior crystalline lens surfaces. The method was tested on an artificial eye with known surfaces geometry and on a human lens in vitro, and demonstrated on three human lenses in vivo. Not correcting for distortion overestimated the anterior lens radius by 25% and the posterior lens radius by more than 65%. In vivo lens surfaces were fitted by biconicoids and Zernike polynomials after distortion correction. The anterior lens radii of curvature ranged from 10.27 to 14.14 mm, and the posterior lens radii of curvature ranged from 6.12 to 7.54 mm. Surface asphericities ranged from −0.04 to −1.96. The lens surfaces were well fitted by quadrics (with variation smaller than 2%, for 5-mm pupils), with low amounts of high order terms. Surface lens astigmatism was significant, with the anterior lens typically showing horizontal astigmatism (Z22 ranging from −11 to −1 µm) and the posterior lens showing vertical astigmatism (Z22 ranging from 6 to 10 µm). PMID:23082289

  17. The aerodynamic performance of several flow control devices for internal flow systems

    NASA Technical Reports Server (NTRS)

    Eckert, W. T.; Wettlaufer, B. M.; Mort, K. W.

    1982-01-01

    An experimental reseach and development program was undertaken to develop and document new flow-control devices for use in the major modifications to the 40 by 80 Foot wind tunnel at Ames Research Center. These devices, which are applicable to other facilities as well, included grid-type and quasi-two-dimensional flow straighteners, louver panels for valving, and turning-vane cascades with net turning angles from 0 deg to 90 deg. The tests were conducted at model scale over a Reynolds number range from 2 x 100,000 to 17 x 100,000, based on chord. The results showed quantitatively the performance benefits of faired, low-blockage, smooth-surface straightener systems, and the advantages of curved turning-vanes with hinge-line gaps sealed and a preferred chord-to-gap ratio between 2.5 and 3.0 for 45 deg or 90 deg turns.

  18. Aerodynamics of a Simple Three-Dimensional High-Lift System

    NASA Technical Reports Server (NTRS)

    Storms, Bruce; Ross, James C.; Takahashi, Timothy T.

    1997-01-01

    Experimental results are presented for a three-element high-lift system with a half-span flap and both a full- and three-quarter span slat. The simplified wing spanned the wind-tunnel test section with no wing sweep or wing tip. Full- and part-span slat configurations were tested to investigate the three-dimensional effects of a finite-span slat in a landing configuration. With a part-span slat, flow visualization and surface pressures revealed two vortices at the flap tip and one at the slat tip. Compared to the full-span slat case, the part-span slat configuration stalled at a lower angle of attack and yielded reduced lift at all angles of attack. At a representative approach attitude (10 deg), wake surveys indicated comparable induced drag for the full- and part-span slat configurations while the profile drag was more than doubled with a part-span slat. The vorticity contribution of the slat-tip vortex was minimal, suggesting that the vortex dissipates through viscous interaction with the main-element boundary layer. The addition of a lower-surface fence at the slat tip yielded two co-rotating vortices and partially alleviated the profile drag increase of the part-span slat.

  19. Adjustable hybrid diffractive/refractive achromatic lens.

    PubMed

    Valley, Pouria; Savidis, Nickolaos; Schwiegerling, Jim; Dodge, Mohammad Reza; Peyman, Gholam; Peyghambarian, N

    2011-04-11

    We demonstrate a variable focal length achromatic lens that consists of a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping points. The refractive lens includes a fluid chamber with a flat glass surface and an opposing elastic polydimethylsiloxane (PDMS) membrane surface. Inserting fluid volume through a pump system into the clear aperture region alters the membrane curvature and adjusts the refractive lens' focal position. Primary chromatic aberration is remarkably reduced through the coupling of the fluidic and diffractive lenses at selected focal lengths. Potential applications include miniature color imaging systems, medical and ophthalmic devices, or any design that utilizes variable focal length achromats.

  20. Aerodynamic flow control of a high lift system with dual synthetic jet arrays

    NASA Astrophysics Data System (ADS)

    Alstrom, Robert Bruce

    Implementing flow control systems will mitigate the vibration and aeroacoustic issues associated with weapons bays; enhance the performance of the latest generation aircraft by reducing their fuel consumption and improving their high angle-of-attack handling qualities; facilitate steep climb out profiles for military transport aircraft. Experimental research is performed on a NACA 0015 airfoil with a simple flap at angle of attack of 16o in both clean and high lift configurations. The results of the active control phase of the project will be discussed. Three different experiments were conducted; they are Amplitude Modulated Dual Location Open Loop Control, Adaptive Control with Amplitude Modulation using Direct Sensor Feedback and Adaptive Control with Amplitude Modulation using Extremum Seeking Control. All the closed loop experiments are dual location. The analysis presented uses the spatial variation of the root mean square pressure fluctuations, power spectral density estimates, Fast Fourier Transforms (FFTs), and time frequency analysis which consists of the application of the Morlet and Mexican Hat wavelets. Additionally, during the course of high speed testing in the wind tunnel, some aeroacoustic phenomena were uncovered; those results will also be presented. A cross section of the results shows that the shape of the RMS pressure distributions is sensitive to forcing frequency. The application of broadband excitation in the case adaptive control causes the flow to select a frequency to lock in to. Additionally, open loop control results in global synchronization via switching between two stable states and closed loop control inhibits the switching phenomena, but rather synchronizes the flow about multiple stable shedding frequencies.

  1. Bidimensional Lens Systems : A Rational Approach To Group Displacements During Focusing And/Or Zooming

    NASA Astrophysics Data System (ADS)

    Angénieux, J. P. L.

    1987-06-01

    Modern objective lenses for cinematography, television or photography, and particularly zoom lenses, are composed of several groups of lenses which are axially displaced during zooming and/or focusing. The number of these groups has increased recently as well as the complexity of their relative movements and functions. In this paper, we give a short history of zooming and focusing techniques ; we discuss the inconvenience of traditional solutions. We then introduce the concept of bidimensional law. We propose a systematic classification of possible lens-types according to the 4 possible types of group. We finally present a few types of lenses in the form of truth tables and parametered diagrams explaining which groups move and how during focusing and/or zooming.

  2. A new VLA/e-MERLIN limit on central images in the gravitational lens system CLASS B1030+074

    NASA Astrophysics Data System (ADS)

    Quinn, Jonathan; Jackson, Neal; Tagore, Amitpal; Biggs, Andrew; Birkinshaw, Mark; Chapman, Scott; De Zotti, Gianfranco; McKean, John; Pérez-Fournon, Ismael; Scott, Douglas; Serjeant, Stephen

    2016-07-01

    We present the new Very Large Array 22 GHz and extended Multi-Element Remote-Linked Interferometer Network 5 GHz observations of CLASS B1030+074, a two-image strong gravitational lens system whose background source is a compact flat-spectrum radio quasar. In such systems we expect a third image of the background source to form close to the centre of the lensing galaxy. The existence and brightness of such images is important for investigation of the central mass distributions of lensing galaxies, but only one secure detection has been made so far in a galaxy-scale lens system. The noise levels achieved in our new B1030+074 images reach 3 μJy beam-1 and represent an improvement in central image constraints of nearly an order of magnitude over previous work, with correspondingly better resulting limits on the shape of the central mass profile of the lensing galaxy. Simple models with an isothermal outer power-law slope now require either the influence of a central supermassive black hole (SMBH), or an inner power-law slope very close to isothermal, in order to suppress the central image below our detection limit. Using the central mass profiles inferred from light distributions in Virgo galaxies, moved to z = 0.5, and matching to the observed Einstein radius, we now find that 45 per cent of such mass profiles should give observable central images, 10 per cent should give central images with a flux density still below our limit, and the remaining systems have extreme demagnification produced by the central SMBH. Further observations of similar objects will therefore allow proper statistical constraints to be placed on the central properties of elliptical galaxies at high redshift.

  3. A liquid crystal adaptive lens

    NASA Technical Reports Server (NTRS)

    Kowel, S. T.; Cleverly, D.

    1981-01-01

    Creation of an electronically controlled liquid crystal lens for use as a focusing mechanism in a multi-element lens system or as an adaptive optical element is analyzed. Varying the index of refraction is shown to be equivalent to the shaping of a solid refracting material. Basic characteristics of liquid crystals, essential for the creation of a lens, are reviewed. The required variation of index of refraction is provided by choosing appropriate electrode voltages. The configuration required for any incoming polarization is given and its theoretical performance in terms of modulation transfer function derived.

  4. Unsteady transonic aerodynamics

    SciTech Connect

    Nixon, D.

    1989-01-01

    Various papers on unsteady transonic aerodynamics are presented. The topics addressed include: physical phenomena associated with unsteady transonic flows, basic equations for unsteady transonic flow, practical problems concerning aircraft, basic numerical methods, computational methods for unsteady transonic flows, application of transonic flow analysis to helicopter rotor problems, unsteady aerodynamics for turbomachinery aeroelastic applications, alternative methods for modeling unsteady transonic flows.

  5. 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.

  6. Assessing Age-Related Changes in the Biomechanical Properties of Rabbit Lens Using a Coaligned Ultrasound and Optical Coherence Elastography System

    PubMed Central

    Wu, Chen; Han, Zhaolong; Wang, Shang; Li, Jiasong; Singh, Manmohan; Liu, Chih-hao; Aglyamov, Salavat; Emelianov, Stanislav; Manns, Fabrice; Larin, Kirill V.

    2015-01-01

    Purpose. To evaluate the capability of a novel, coaligned focused ultrasound and phase-sensitive optical coherence elastography (US-OCE) system to assess age-related changes in biomechanical properties of the crystalline lens in situ. Methods. Low-amplitude elastic deformations in young and mature rabbit lenses were measured by an US-OCE system consisting of a spectral-domain optical coherence tomography (OCT) system coaligned with a focused ultrasound system used to produce a transient force on the lens surface. Uniaxial compressional tests were used to validate the OCE data. Results. The OCE measurements showed that the maximum displacements of the young rabbit lenses were significantly larger than those of the mature lenses, indicating a gradual increase of the lens stiffness with age. Temporal analyses of the displacements also demonstrate a similar trend of elastic properties in these lenses. The stress-strain measurements using uniaxial mechanical tests confirmed the results obtained by the US-OCE system. Conclusions. The results demonstrate that the US-OCE system can be used for noninvasive analysis and quantification of lens biomechanical properties in situ and possibly in vivo. PMID:25613945

  7. Aerodynamic Simulation of the MARINTEK Braceless Semisubmersible Wave Tank Tests

    NASA Astrophysics Data System (ADS)

    Stewart, Gordon; Muskulus, Michael

    2016-09-01

    Model scale experiments of floating offshore wind turbines are important for both platform design for the industry as well as numerical model validation for the research community. An important consideration in the wave tank testing of offshore wind turbines are scaling effects, especially the tension between accurate scaling of both hydrodynamic and aerodynamic forces. The recent MARINTEK braceless semisubmersible wave tank experiment utilizes a novel aerodynamic force actuator to decouple the scaling of the aerodynamic forces. This actuator consists of an array of motors that pull on cables to provide aerodynamic forces that are calculated by a blade-element momentum code in real time as the experiment is conducted. This type of system has the advantage of supplying realistically scaled aerodynamic forces that include dynamic forces from platform motion, but does not provide the insights into the accuracy of the aerodynamic models that an actual model-scale rotor could provide. The modeling of this system presents an interesting challenge, as there are two ways to simulate the aerodynamics; either by using the turbulent wind fields as inputs to the aerodynamic model of the design code, or by surpassing the aerodynamic model and using the forces applied to the experimental turbine as direct inputs to the simulation. This paper investigates the best practices of modeling this type of novel aerodynamic actuator using a modified wind turbine simulation tool, and demonstrates that bypassing the dynamic aerodynamics solver of design codes can lead to erroneous results.

  8. Quiet Clean Short-Haul Experimental Engine (QCSEE) Over-The-Wing (OTW) propulsion system test report. Volume 2: Aerodynamics and performance. [engine performance tests to define propulsion system performance on turbofan engines

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The design and testing of the over the wing engine, a high bypass, geared turbofan engine, are discussed. The propulsion system performance is examined for uninstalled performance and installed performance. The fan aerodynamic performance and the D nozzle and reverser thrust performance are evaluated.

  9. High Resolution Imaging of the Anomalous Flux-Ratio Gravitational Lens System CLASS B2045+265: Dark Or Luminous Satellites?

    SciTech Connect

    McKean, J.P.; Koopmans, L.V.E.; Flack, C.E.; Fassnacht, C.D.; Thompson, D.; Matthews, K.; Blandford, R.D.; Readhead, A.C.S.; Soifer, B.T.; /UC, Davis /Bonn, Max Planck Inst., Radioastron. /Kapteyn Astron. Inst., Groningen /Bemidji State U. /Caltech /KIPAC, Menlo Park /Cornell U., Astron. Dept.

    2006-11-10

    The existence of flux-ratio anomalies between fold and cusp images in galaxy-scale strong-lens systems has led to an interpretation based on the presence of a high mass-fraction of cold-dark-matter (CDM) substructures around galaxies, as predicted by numerical N-body simulations. These substructures can cause large perturbations of the image magnifications, leading to changes in the image flux ratios. The flux-ratio anomaly is particularly evident in the radio-loud quadruple gravitational lens system CLASS B2045+265. In this paper, new high-resolution radio, optical, and infrared imaging of B2045+265 is presented which sheds more light on this anomaly and its possible causes. First, deep Very Long Baseline Array observations show very compact images, possibly with a hint of a jet, but with no evidence for differential scattering or scatter broadening. Hence, the flux-ratio anomaly is unlikely to be caused by refractive scattering in either the Milky Way or the lens galaxy. Second, optical and infrared observations with the Hubble Space Telescope and through Adaptive-Optics imaging with the W. M. Keck Telescope, show a previously undiscovered object--interpreted as a (tidally disrupted) dwarf satellite based on its colors and slight extension--between the main lens galaxy and the three anomalous flux-ratio images. Third, color variations in the early-type lens galaxy indicate recent star-formation, possibly the result of secondary infall of gas-rich satellites. A population of young galaxies around the lens system could explain the previously discovered strong [O II] emission. However, spiral structure and/or normal star formation in the lens galaxy cannot be excluded. In light of these new data, we propose a lens model for the system, including the observed dwarf satellite, which reproduces all positional and flux-ratio constraints, without the need for additional CDM substructure. Although the model is peculiar in that the dwarf galaxy must be highly flattened

  10. Propagation of flat-topped multi-Gaussian beams through a double-lens system with apertures.

    PubMed

    Gao, Yanqi; Zhu, Baoqiang; Liu, Daizhong; Lin, Zunqi

    2009-07-20

    A general model for different apertures and flat-topped laser beams based on the multi-Gaussian function is developed. The general analytical expression for the propagation of a flat-topped beam through a general double-lens system with apertures is derived using the above model. Then, the propagation characteristics of the flat-topped beam through a spatial filter are investigated by using a simplified analytical expression. Based on the Fluence beam contrast and the Fill factor, the influences of a pinhole size on the propagation of the flat-topped multi-Gaussian beam (FMGB) through the spatial filter are illustrated. An analytical expression for the propagation of the FMGB through the spatial filter with a misaligned pinhole is presented, and the influences of the pinhole offset are evaluated.

  11. Oblique incidence reflectometry: optical models and measurements using a side-viewing gradient index lens-based endoscopic imaging system

    NASA Astrophysics Data System (ADS)

    Wall, R. Andrew; Barton, Jennifer K.

    2014-06-01

    A side-viewing, 2.3-mm diameter oblique incidence reflectometry endoscope has been designed to obtain optical property measurements of turbid samples. Light from a single-mode fiber is relayed obliquely onto the tissue with a gradient index lens-based distal optics assembly and the resulting diffuse reflectance profile is imaged and collected with a 30,000 element, 0.72 mm clear aperture fiber bundle. Sampling the diffuse reflectance in two-dimensions allows for fitting of the reflected intensity profile to a well-known theoretical model, permitting the extraction of both absorption and reduced scattering coefficients of the tissue sample. Models and measurements of the endoscopic imaging system are presented in tissue phantoms and in vivo mouse colon, verifying the endoscope's capabilities to accurately measure effective attenuation coefficient and differentiate diseased from normal colon.

  12. Computational Aerodynamic Simulations of a 1215 ft/sec Tip Speed Transonic Fan System Model for Acoustic Methods Assessment and Development

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2014-01-01

    Computational Aerodynamic simulations of a 1215 ft/sec tip speed transonic fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, low-noise research fan/nacelle model that has undergone extensive experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating points simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, which for this model did not include a split flow path with core and bypass ducts. As a result, it was only necessary to adjust fan rotational speed in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. Computed blade row flow fields at all fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the flow fields at all operating conditions reveals no excessive boundary layer separations or related secondary-flow problems.

  13. Imaging characteristics of ball lens

    NASA Astrophysics Data System (ADS)

    Li, Qinghui; Shao, Xiaopeng

    2014-05-01

    In most digital imaging applications, high-resolution imaging or videos are usually desired for later processing and analysis. The desire for high-resolution stems from two principal application areas: improvement of pictorial information for human interpretation, and helping representation for automatic machine preception. While the image sensors limit the spatial resolution of the image, the image details are also limited by the optical system, due to diffraction, and aberration1. Monocentric lens are an attractive option for gigapixel camera because the symmetrical design focuses light identically coming from any direction. Marks and Brady proposed a monocentric lens design imaging 40 gigapixels with an f-number of 2.5 and resolving 2 arcsec over a 120 degrees field of view2. Recently, Cossairt, Miau, and Nayer proposed a proof-of-concept gigapixel computational camera consisting of a large ball lens shared by several small planar sensors coupled with a deblurring step3. The design consists of a ball element resulting in a lens that is both inexpensive to produce and easy to align. Because the resolution of spherical lens is fundamentally limited by geometric aberrations, the imaging characteristics of the ball lens is expressed by the geometrical aberrations, in which the general equations for the primary aberration of the ball lens are given. The effect of shifting the stop position on the aberrations of a ball lens is discussed. The variation of the axial chromatic aberration with the Abbe V-number when the refraction index takes different values is analyzed. The variation of the third-order spherical aberration ,the fifth-order spherical aberration and the spherical aberration obtained directly from ray tracing with the f-number is discussed. The other imaging evaluation merits, such as the spot diagram, the modulation transfer function(MTF) and the encircled energy are also described. Most of the analysis of the ball lens is carried out using OSLO optics

  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. 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.

  16. In-Situ Load System for Calibrating and Validating Aerodynamic Properties of Scaled Aircraft in Ground-Based Aerospace Testing Applications

    NASA Technical Reports Server (NTRS)

    Commo, Sean A. (Inventor); Lynn, Keith C. (Inventor); Landman, Drew (Inventor); Acheson, Michael J. (Inventor)

    2016-01-01

    An In-Situ Load System for calibrating and validating aerodynamic properties of scaled aircraft in ground-based aerospace testing applications includes an assembly having upper and lower components that are pivotably interconnected. A test weight can be connected to the lower component to apply a known force to a force balance. The orientation of the force balance can be varied, and the measured forces from the force balance can be compared to applied loads at various orientations to thereby develop calibration factors.

  17. Low-speed aerodynamic characteristics of a 42 deg swept high-wing model having a double-slotted flap system and a supercritical airfoil

    NASA Technical Reports Server (NTRS)

    Fournier, P. G.; Goodson, K. W.

    1974-01-01

    A low-speed investigation was conducted over an angle-of-attack range from about -4 deg to 20 deg in the Langley V/STOL tunnel to determine the effects of a double-slotted flap, high-lift system on the aerodynamic characteristics of a 42 deg swept high-wing model having a supercritical airfoil. The wing had an aspect ratio of 6.78 and a taper ratio of 0.36; the double-slotted flap consisted of a 35-percent-chord flap with a 15-percent-chord vane. The model was tested with a 15-percent-chord leading-edge slat.

  18. A New Lens for Supporting and Studying Science Teacher Reflections: Situating the Self in the [Activity] System

    ERIC Educational Resources Information Center

    Criswell, Brett; Calandra, Brendan; Puvirajah, Anton; Brantley-Dias, Laurie

    2015-01-01

    This paper presents a new lens for analyzing written reflections on the teaching experiences of pre-service [science] teachers. The lens, which borrows heavily from Activity Theory, allows science education researchers and teacher educators to identify tensions, disturbances, conflicts, and contradictions within teachers' written reflections as a…

  19. Lens coupled tunable Young's double pinhole system for hard X-ray spatial coherence characterization.

    PubMed

    Lyubomirskiy, Mikhail; Snigireva, Irina; Snigirev, Anatoly

    2016-06-13

    We have implemented a modified Young's double slit experiment using pinholes with tunable separation distance coupled with compound refractive lens for hard X-ray spatial coherence characterization. Varying distance between the apertures provides a high sensitivity to the determination of spatial coherence across a wide range of experimental parameters. The use of refractive lenses as a Fourier transformer ensures far field registration conditions and allows the realization of a very compact experimental setup in comparison with the classical Young technique and its derivatives. The tunable double aperture interferometer was experimentally tested at the ESRF ID06 beamline in the energy range from 8 to 25 keV. The spatial coherence and the source size were measured by evaluating the visibility of the interference fringes at various separation distances between the apertures and this value agrees very well with the data obtained by other techniques. The proposed scheme can be used for comprehensive characterization of the coherence properties of the source on low emittance synchrotrons in the hard X-ray region.

  20. Cataract produced by tyrosinase and tyrosine systems in rabbit lens in vitro

    PubMed Central

    Srivastava, Satish K.; Beutler, Ernest

    1969-01-01

    1. Cataracts were developed by incubating rabbit lenses for 22hr. at 37° in a culture medium containing tyrosine and tyrosinase (EC 1.10.3.1). 2. A 45% diminution in the content of GSH and significant inhibition of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) activity were observed in the cataractous lenses compared with controls. 3. GSSG accumulated in both cataractous and control lenses. Significant amounts of GSSG were transported outward from the cataractous lenses and small amounts from control lenses. 4. Transport of GSSG from rabbit lens incubated in a diffusate of plasma from a naphthalene-fed rabbit was also observed. 5. GSSG was found in the aqueous humour obtained between 2 and 24hr. after feeding of naphthalene to rabbits; subsequently the GSSG in the aqueous humour decreased to almost undetectable amounts in 48hr.; in controls, GSSG was not detectable. 6. A possible mechanism of formation of experimental and senile cataract is briefly discussed. PMID:4979383

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Converging or Diverging Lens?

    ERIC Educational Resources Information Center

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  6. The SADI Personal Health Lens: A Web Browser-Based System for Identifying Personally Relevant Drug Interactions

    PubMed Central

    Vandervalk, Ben; McCarthy, E Luke; Cruz-Toledo, José; Klein, Artjom; Baker, Christopher J O; Dumontier, Michel

    2013-01-01

    Background The Web provides widespread access to vast quantities of health-related information that can improve quality-of-life through better understanding of personal symptoms, medical conditions, and available treatments. Unfortunately, identifying a credible and personally relevant subset of information can be a time-consuming and challenging task for users without a medical background. Objective The objective of the Personal Health Lens system is to aid users when reading health-related webpages by providing warnings about personally relevant drug interactions. More broadly, we wish to present a prototype for a novel, generalizable approach to facilitating interactions between a patient, their practitioner(s), and the Web. Methods We utilized a distributed, Semantic Web-based architecture for recognizing personally dangerous drugs consisting of: (1) a private, local triple store of personal health information, (2) Semantic Web services, following the Semantic Automated Discovery and Integration (SADI) design pattern, for text mining and identifying substance interactions, (3) a bookmarklet to trigger analysis of a webpage and annotate it with personalized warnings, and (4) a semantic query that acts as an abstract template of the analytical workflow to be enacted by the system. Results A prototype implementation of the system is provided in the form of a Java standalone executable JAR file. The JAR file bundles all components of the system: the personal health database, locally-running versions of the SADI services, and a javascript bookmarklet that triggers analysis of a webpage. In addition, the demonstration includes a hypothetical personal health profile, allowing the system to be used immediately without configuration. Usage instructions are provided. Conclusions The main strength of the Personal Health Lens system is its ability to organize medical information and to present it to the user in a personalized and contextually relevant manner. While this

  7. Contact lens in keratoconus

    PubMed Central

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  8. The Lens Capsule

    PubMed Central

    Danysh, Brian P.; Duncan, Melinda K.

    2009-01-01

    The lens capsule is a modified basement membrane that completely surrounds the ocular lens. It is known that this extracellular matrix is important for both the structure and biomechanics of the lens in addition to providing informational cues to maintain lens cell phenotype. This review covers the development and structure of the lens capsule, lens diseases associated with mutations in extracellular matrix genes and the role of the capsule in lens function including those proposed for visual accommodation, selective permeability to infectious agents, and cell signaling. PMID:18773892

  9. Influences of Detection Pinhole and Sample Flow on Thermal Lens Detection in Microfluidic Systems

    NASA Astrophysics Data System (ADS)

    Liu, Mingqiang; Franko, Mladen

    2014-12-01

    Thermal lens microscopy (TLM), due to its high temporal () and spatial resolution (), has been coupled to lab-on-chip chemistry for detection of a variety of compounds in chemical or biological fields. Due to the very short optical path length (usually below 100 ) in a microchip, the sensitivity of TLM is unfortunately still 10 to 100 times lower than conventional TLS with 1 cm sample length. Optimization of the TLM optical configuration was made with respect to different pinhole aperture-to-beam size ratios for the best signal-to-noise ratio. In the static mode, the instrumental noise comes mainly from the shot noise of the probe beam when the chopper frequency is over 1 kHz or from the flicker noise of the probe beam at low frequencies. In the flowing mode, the flow-induced noise becomes dominant when the flow rate is high. At a given flow rate, fluids with a higher density and/or a higher viscosity will cause larger flow-induced noise. As an application, a combined microfluidic flow injection analysis ()-TLM device was developed for rapid determination of pollutants by colorimetric reactions. Hexavalent chromium [Cr(VI)] was measured as a model analyte. Analytical signals for 12 sample injections in 1 min have been recorded by the FIA-TLM. For injections of sub-L samples into the microfluidic stream in a deep microchannel, a limit of detection of was achieved for Cr(VI) in water at 60 mW excitation power.

  10. Role of the lens capsule on the mechanical accommodative response in a lens stretcher

    PubMed Central

    Ziebarth, Noël M.; Borja, David; Arrieta, Esdras; Aly, Mohamed; Manns, Fabrice; Dortonne, Isabelle; Nankivil, Derek; Jain, Rakhi; Parel, Jean-Marie

    2009-01-01

    Purpose To determine if changes in elastic properties of the lens capsule ex vivo with age contribute to the forces required to accommodate. Methods Post-mortem human (n=22; age average: 41±17years, range: 6–71 years) and cynomolgus monkey (n=19; age average: 7.7±1.8 years, range: 4.2–10 years) tissues including the lens, capsule, zonules, ciliary body, and sclera were mounted in an optomechanical lens stretching system. Starting at zero load, the sclera was symmetrically stretched to 2mm in 0.25 steps at a speed of 0.1mm.s−1. The load and lens diameter were measured at each step. The lens contents were removed through a mini-capsulorhexis. The stretching cycles were repeated on the empty capsular bag. The forces required to stretch the natural lens and empty bag were quantified as a function of age and compared. Results The force required to stretch the empty lens capsule was independent of age (human=2.6–34.9g/mm [25.2–342.7mN/mm], monkey=8.2–21.3g/mm [80.3–208.6mN/mm]). The ratio of the force required to stretch the empty lens capsule to the force required to stretch the natural lens decreases with age in human and monkey lenses (p=0.003, p=0.72, respectively). Conclusions The mechanical properties of the empty lens capsule assessed ex vivo in a lens stretcher remain constant with age, suggesting that the changes in elasticity of the lens capsule do not play a significant role in presbyopia. In young eyes, the lens capsule determines the force required to stretch the whole lens. The age-related increase in force required to stretch the lens is due to changes in the lens contents. PMID:18515568

  11. Aerodynamic and Aeroelastic Insights using Eigenanalysis

    NASA Technical Reports Server (NTRS)

    Heeg, Jennifer; Dowell, Earl H.

    1999-01-01

    This paper presents novel analytical results for eigenvalues and eigenvectors produced using discrete time aerodynamic and aeroelastic models. An unsteady, incompressible vortex lattice aerodynamic model is formulated in discrete time; the importance of several modeling parameters is examined. A detailed study is made of the behavior of the aerodynamic eigenvalues both in discrete and continuous time. The aerodynamic model is then incorporated into aeroelastic equations of motion. Eigenanalyses of the coupled equations produce stability results and modal characteristics which are valid for critical and non-critical velocities. Insight into the modeling and physics associated with aeroelastic system behavior is gained by examining both the eigenvalues and the eigenvectors. Potential pitfalls in discrete time model construction and analysis are examined.

  12. Lens design based on lens form parameters using Gaussian brackets

    NASA Astrophysics Data System (ADS)

    Yuan, Xiangyu; Cheng, Xuemin

    2014-11-01

    The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.

  13. Small-Scale Trial for Evaluating Directional Resolution of Single Spherical Biconcave Acoustic Lens in Designing of Ambient Noise Imaging System

    NASA Astrophysics Data System (ADS)

    Mori, Kazuyoshi; Ogasawara, Hanako; Nakamura, Toshiaki

    2008-05-01

    Ambient noise imaging (ANI) is the revolutionary idea of detecting objects by using natural ocean background noise. From the analysis results obtained by the finite difference time domain (FDTD) method in our previous studies, it was supposed that a spherical biconcave lens with an aperture diameter of 2.0 m has a sufficient directional resolution (for example, the beam width is 1° at 60 kHz) for realizing an ANI system. In this study, to confirm the analysis results, we performed a small-scale trial of one-fifth space in a water tank. The lens, made of acrylic resin, has an aperture diameter of 400 mm and a radius of curvature of 500 mm. A burst pulse of 25 cycles at 300 kHz, whose frequency increases 5 times, was radiated from the sound source. The sound pressure after passage through the acoustic lens was measured by moving the receiver around the image point. Results show that the shapes of -3 dB areas are similar to the FDTD analysis results at small incidence angles. It was verified that this lens has a sufficient directional resolution for use in the ANI system, because -3 dB areas do not overlap each other.

  14. Advanced turboprop installation aerodynamics

    NASA Technical Reports Server (NTRS)

    Smith, R. C.

    1981-01-01

    The expected aerodynamic effects of a propfan installed on a thick supercritical wing are summarized qualitatively. Nacelle/wing and jet interactions, slipstream incremental velocity, nonuniform inflow, and swirl loss recovery are discussed.

  15. 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)

  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. 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.

  18. Aerodynamic investigation by infrared imaging

    NASA Technical Reports Server (NTRS)

    Roberts, A. Sidney, Jr.; Mcree, Griffith J.; Gartenberg, Ehud

    1988-01-01

    Infrared imaging systems can be used to measure temperatures of actively heated bodies immersed in an airstream. This monitoring of the convective heat transfer process, provides also information about the interaction between the body and the flow. The concept appeals to Nusselt/Reynolds numbers relations in order to produce data of interest from surface temperatures. Two test cases are presented and reference is made to analytical results: the mapping of a laminar jet and the temperature distribution along a constant power heated flat plate in laminar boundary layer regime. Although this research is currently focused on low speed aerodynamics, the extension to high speed aerodynamics, where the body undergoes frictional heating is of interest in this context, too.

  19. 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.

  20. Endoscopic inspection using a panoramic annular lens

    NASA Technical Reports Server (NTRS)

    Gilbert, John A.; Matthys, Donald R.

    1991-01-01

    The objective of this one year study was to design, build, and demonstrate a prototype system for cavity inspection. A cylindrical view of the cavity interior was captured in real time through a compound lens system consisting of a unique panoramic annular lens and a collector lens. Images, acquired with a digitizing camera and stored in a desktop computer, were manipulated using image processing software to aid in visual inspection and qualitative analysis. A detailed description of the lens and its applications is given.

  1. The robustness of angular diameter distances to the lens in the B1608+656 and RXJ1131-1231 systems

    NASA Astrophysics Data System (ADS)

    Holanda, R. F. L.

    2016-11-01

    The angular diameter distance of lens, DAol, of strong gravitational lensing systems has been claimed as a cosmic standard ruler. The first measurements for this distance were recently obtained to two well-known systems: B1608+656 and RXJ1131-1231. However, there is a range of possible systematic uncertainties which must be addressed in order to turn these systems into useful cosmic probes. In this paper, we confront DAol with luminosity distances of type Ia supernovae and angular diameter distances of galaxy clusters to search for tensions between these cosmological measurements using the cosmic distance duality relation. No tension was verified with the present data, showing the robustness of the assumptions used to describe the lens systems.

  2. Effect of rotor wake on aerodynamic characteristics of a 1/6 scale model of the rotor systems research aircraft. [in the Langley V/STOL tunnel

    NASA Technical Reports Server (NTRS)

    Mineck, R. E.

    1977-01-01

    Tests were conducted in the Langley V/STOL tunnel to determine the effect of the main-rotor wake on the aerodynamic characteristics of the rotor systems research aircraft. A 1/6-scale model with a 4-blade articulated rotor was used to determine the effect of the rotor wake for the compound configuration. Data were obtained over a range of angles of attack, angles of sideslip, auxiliary engine thrusts, rotor collective pitch angles, and rotor tip-path plane angles for several main-rotor advance ratios. Separate results are presented for the forces and moments on the airframe, the wing, and the tail. An analysis of the test data indicates significant changes in the aerodynamic characteristics. The rotor wake increases the longitudinal static stability, the effective dihedral, and the lateral static stability of the airframe. The rotor induces a downwash on the wing. This downwash decreases the wing lift and increases the drag. The asymmetrical rotor wake induces a differential lift across the wing and a subsequent rolling moment. These rotor induced effects on the wing become smaller with increasing forward speed.

  3. Computational Aerodynamic Simulations of a 1484 ft/sec Tip Speed Quiet High-Speed Fan System Model for Acoustic Methods Assessment and Development

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2014-01-01

    Computational Aerodynamic simulations of a 1484 ft/sec tip speed quiet high-speed fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, low-noise research fan/nacelle model that has undergone experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating points simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, which includes a core duct and a bypass duct that merge upstream of the fan system nozzle. As a result, only fan rotational speed and the system bypass ratio, set by means of a translating nozzle plug, were adjusted in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. Computed blade row flow fields at all fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the computed flow fields reveals no excessive or critical boundary layer separations or related secondary-flow problems, with the exception of the hub boundary layer at the core duct entrance. At that location a significant flow separation is present. The region of local flow

  4. Multi-fields direct design approach in 3D: calculating a two-surface freeform lens with an entrance pupil for line imaging systems.

    PubMed

    Nie, Yunfeng; Thienpont, Hugo; Duerr, Fabian

    2015-12-28

    Including an entrance pupil in optical systems provides clear benefits for balancing the overall performance of freeform and/or rotationally symmetric imaging systems. Current existing direct design methods that are based on perfect imaging of few discrete ray bundles are not well suited for wide field of view systems. In this paper, a three-dimensional multi-fields direct design approach is proposed to balance the full field imaging performance of a two-surface freeform lens. The optical path lengths and image points of numerous fields are calculated during the procedures, wherefore very few initial parameters are needed in advance. Design examples of a barcode scanner lens as well as a line imaging objective are introduced to demonstrate the effectiveness of this method. PMID:26832061

  5. 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.

  6. Aerodynamic-structural study of canard wing, dual wing, and conventional wing systems for general aviation applications

    NASA Technical Reports Server (NTRS)

    Selberg, B. P.; Cronin, D. L.

    1985-01-01

    An analytical aerodynamic-structural airplane configuration study was conducted to assess performance gains achievable through advanced design concepts. The mission specification was for 350 mph, range of 1500 st. mi., at altitudes between 30,000 and 40,000 ft. Two payload classes were studied - 1200 lb (6 passengers) and 2400 lb (12 passengers). The configurations analyzed included canard wings, closely coupled dual wings, swept forward - swept rearward wings, joined wings, and conventional wing tail arrangements. The results illustrate substantial performance gains possible with the dual wing configuration. These gains result from weight savings due to predicted structural efficiencies. The need for further studies of structural efficiencies for the various advanced configurations was highlighted.

  7. Aerodynamics model for a generic ASTOVL lift-fan aircraft

    NASA Technical Reports Server (NTRS)

    Birckelbaw, Lourdes G.; Mcneil, Walter E.; Wardwell, Douglas A.

    1995-01-01

    This report describes the aerodynamics model used in a simulation model of an advanced short takeoff and vertical landing (ASTOVL) lift-fan fighter aircraft. The simulation model was developed for use in piloted evaluations of transition and hover flight regimes, so that only low speed (M approximately 0.2) aerodynamics are included in the mathematical model. The aerodynamic model includes the power-off aerodynamic forces and moments and the propulsion system induced aerodynamic effects, including ground effects. The power-off aerodynamics data were generated using the U.S. Air Force Stability and Control Digital DATCOM program and a NASA Ames in-house graphics program called VORVIEW which allows the user to easily analyze arbitrary conceptual aircraft configurations using the VORLAX program. The jet-induced data were generated using the prediction methods of R. E. Kuhn et al., as referenced in this report.

  8. Aerodynamics of high-speed railway train

    NASA Astrophysics Data System (ADS)

    Raghunathan, Raghu S.; Kim, H.-D.; Setoguchi, T.

    2002-10-01

    Railway train aerodynamic problems are closely associated with the flows occurring around train. Much effort to speed up the train system has to date been paid on the improvement of electric motor power rather than understanding the flow around the train. This has led to larger energy losses and performance deterioration of the train system, since the flows around train are more disturbed due to turbulence of the increased speed of the train, and consequently the flow energies are converted to aerodynamic drag, noise and vibrations. With the speed-up of train, many engineering problems which have been neglected at low train speeds, are being raised with regard to aerodynamic noise and vibrations, impulse forces occurring as two trains intersect each other, impulse wave at the exit of tunnel, ear discomfort of passengers inside train, etc. These are of major limitation factors to the speed-up of train system. The present review addresses the state of the art on the aerodynamic and aeroacoustic problems of high-speed railway train and highlights proper control strategies to alleviate undesirable aerodynamic problems of high-speed railway train system.

  9. Unsteady Aerodynamic Force Sensing from Measured Strain

    NASA Technical Reports Server (NTRS)

    Pak, Chan-Gi

    2016-01-01

    , velocity, and acceleration sensors. This research demonstrates the feasibility of obtaining induced drag and lift forces through the use of distributed sensor technology with measured strain data. An active induced drag control system thus can be designed using the two computed aerodynamic forces, induced drag and lift, to improve the fuel efficiency of an aircraft. Interpolation elements between structural finite element grids and the CFD grids and centroids are successfully incorporated with the unsteady aeroelastic computation scheme. The most critical technology for the success of the proposed approach is the robust on-line parameter estimator, since the least-squares curve fitting method depends heavily on aeroelastic system frequencies and damping factors.

  10. Aerodynamics. [numerical simulation using supercomputers

    NASA Technical Reports Server (NTRS)

    Graves, Randolph 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 CO2.

  11. 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/.

  12. Contact Lens Care

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More ... 1088, www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative ...

  13. Contact Lens Solution Toxicity

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  14. Precision evaluation of lens systems using a nodal slide/MTF optical bench

    NASA Astrophysics Data System (ADS)

    Doherty, Victor J.; Chapnik, Philip D.

    1992-01-01

    A compact, self-contained production instrument designed to permit the rapid and precise performance characterization of a wide variety of lenses and optical systems has been developed by Eidolon Corporation. The Eidolon Production Nodal Slide/MTF Measurement System can be used to measure effective focal length (EFL), distortion, field curvature, chromatic aberration, spot size, and modulation transfer function (MTF).

  15. 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.

  16. Adaptive neuro-fuzzy prediction of modulation transfer function of optical lens system

    NASA Astrophysics Data System (ADS)

    Petković, Dalibor; Shamshirband, Shahaboddin; Anuar, Nor Badrul; Md Nasir, Mohd Hairul Nizam; Pavlović, Nenad T.; Akib, Shatirah

    2014-07-01

    The quantitative assessment of image quality is an important consideration in any type of imaging system. The modulation transfer function (MTF) is a graphical description of the sharpness and contrast of an imaging system or of its individual components. The MTF is also known and spatial frequency response. The MTF curve has different meanings according to the corresponding frequency. The MTF of an optical system specifies the contrast transmitted by the system as a function of image size, and is determined by the inherent optical properties of the system. In this study, the adaptive neuro-fuzzy (ANFIS) estimator is designed and adapted to predict MTF value of the actual optical system. Neural network in ANFIS adjusts parameters of membership function in the fuzzy logic of the fuzzy inference system. The back propagation learning algorithm is used for training this network. This intelligent estimator is implemented using MATLAB/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

  17. Modulation transfer function estimation of optical lens system by adaptive neuro-fuzzy methodology

    NASA Astrophysics Data System (ADS)

    Petković, Dalibor; Shamshirband, Shahaboddin; Pavlović, Nenad T.; Anuar, Nor Badrul; Kiah, Miss Laiha Mat

    2014-07-01

    The quantitative assessment of image quality is an important consideration in any type of imaging system. The modulation transfer function (MTF) is a graphical description of the sharpness and contrast of an imaging system or of its individual components. The MTF is also known and spatial frequency response. The MTF curve has different meanings according to the corresponding frequency. The MTF of an optical system specifies the contrast transmitted by the system as a function of image size, and is determined by the inherent optical properties of the system. In this study, the adaptive neuro-fuzzy (ANFIS) estimator is designed and adapted to estimate MTF value of the actual optical system. Neural network in ANFIS adjusts parameters of membership function in the fuzzy logic of the fuzzy inference system. The back propagation learning algorithm is used for training this network. This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

  18. Optical tweezers and surface plasmon resonance combination system based on the high numerical aperture lens

    NASA Astrophysics Data System (ADS)

    Shan, Xuchen; Zhang, Bei; Lan, Guoqiang; Wang, Yiqiao; Liu, Shugang

    2015-11-01

    Biology and medicine sample measurement takes an important role in the microscopic optical technology. Optical tweezer has the advantage of accurate capture and non-pollution of the sample. The SPR(surface plasmon resonance) sensor has so many advantages include high sensitivity, fast measurement, less consumption of sample and label-free detection of biological sample that the SPR sensing technique has been used for surface topography, analysis of biochemical and immune, drug screening and environmental monitoring. If they combine, they will play an important role in the biological, chemical and other subjects. The system we propose use the multi-axis cage system, by using the methods of reflection and transmiss ion to improve the space utilization. The SPR system and optical tweezer were builtup and combined in one system. The cage of multi-axis system gives full play to its accuracy, simplicity and flexibility. The size of the system is 20 * 15 * 40 cm3 and thus the sample can be replaced to switch between the optical tweezers system and the SPR system in the small space. It means that we get the refractive index of the sample and control the particle in the same system. In order to control the revolving stage, get the picture and achieve the data stored automatically, we write a LabVIEW procedure. Then according to the data from the back focal plane calculate the refractive index of the sample. By changing the slide we can trap the particle as optical tweezer, which makes us measurement and trap the sample at the same time.

  19. 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.

  20. Comparison of aerodynamic characteristics of pentagonal and hexagonal shaped bridge decks

    NASA Astrophysics Data System (ADS)

    Haque, Md. Naimul; Katsuchi, Hiroshi; Yamada, Hitoshi; Nishio, Mayuko

    2016-07-01

    Aerodynamics of the long-span bridge deck should be well understood for an efficient design of the bridge system. For practical bridges various deck shapes are being recommended and adopted, yet not all of their aerodynamic behaviors are well interpreted. In the present study, a numerical investigation was carried out to explore the aerodynamic characteristics of pentagonal and hexagonal shaped bridge decks. A relative comparison of steady state aerodynamic responses was made and the flow field was critically analyzed for better understanding the aerodynamic responses. It was found that the hexagonal shaped bridge deck has better aerodynamic characteristics as compared to the pentagonal shaped bridge deck.

  1. Nonlinear aerodynamic wing design

    NASA Technical Reports Server (NTRS)

    Bonner, Ellwood

    1985-01-01

    The applicability of new nonlinear theoretical techniques is demonstrated for supersonic wing design. The new technology was utilized to define outboard panels for an existing advanced tactical fighter model. Mach 1.6 maneuver point design and multi-operating point compromise surfaces were developed and tested. High aerodynamic efficiency was achieved at the design conditions. A corollary result was that only modest supersonic penalties were incurred to meet multiple aerodynamic requirements. The nonlinear potential analysis of a practical configuration arrangement correlated well with experimental data.

  2. Computational aerodynamics and design

    NASA Technical Reports Server (NTRS)

    Ballhaus, W. F., Jr.

    1982-01-01

    The role of computational aerodynamics in design is reviewed with attention given to the design process; the proper role of computations; the importance of calibration, interpretation, and verification; the usefulness of a given computational capability; and the marketing of new codes. Examples of computational aerodynamics in design are given with particular emphasis on the Highly Maneuverable Aircraft Technology. Finally, future prospects are noted, with consideration given to the role of advanced computers, advances in numerical solution techniques, turbulence models, complex geometries, and computational design procedures. Previously announced in STAR as N82-33348

  3. A Magnification Lens for Interactive Volume Visualization

    SciTech Connect

    LaMar, E; Hamann, B; Joy, K I

    2001-07-19

    Volume visualization of large data sets suffers from the same problem that many other visualization modalities suffer from: either one can visualize the entire data set and lose small details or visualize a small region and lose the context. In this paper, they present a magnification lens technique for volume visualization. While the notion of a magnification-lens is not new, and other techniques attempt to simulate the physical properties of a magnifying lens, their contribution is in developing a magnification lens that is fast, can be implemented using a fairly small software overhead, and has a natural, intuitive appearance. The issue with magnification lens is the border, or transition, region. The lens center and exterior have a constant zoom factor, and are simple to render. It is the border region that blends between the external and interior magnification, and has a non-constant magnification. They use the perspective-correct textures capability, available in most current graphics systems, to produce a lens with a tessellated border region that approximates linear compression with respect to the radius of the magnification lens. They discuss how a cubic border can mitigate the discontinuities resulting from the use of a linear function, without significant performance loss. They discuss various issues concerning development of a three-dimensional magnification lens.

  4. The evolution of early cellular systems viewed through the lens of biological interactions

    PubMed Central

    Poole, Anthony M.; Lundin, Daniel; Rytkönen, Kalle T.

    2015-01-01

    The minimal cell concept represents a pragmatic approach to the question of how few genes are required to run a cell. This is a helpful way to build a parts-list, and has been more successful than attempts to deduce a minimal gene set for life by inferring the gene repertoire of the last universal common ancestor, as few genes trace back to this hypothetical ancestral state. However, the study of minimal cellular systems is the study of biological outliers where, by practical necessity, coevolutionary interactions are minimized or ignored. In this paper, we consider the biological context from which minimal genomes have been removed. For instance, some of the most reduced genomes are from endosymbionts and are the result of coevolutionary interactions with a host; few such organisms are “free-living.” As few, if any, biological systems exist in complete isolation, we expect that, as with modern life, early biological systems were part of an ecosystem, replete with organismal interactions. We favor refocusing discussions of the evolution of cellular systems on processes rather than gene counts. We therefore draw a distinction between a pragmatic minimal cell (an interesting engineering problem), a distributed genome (a system resulting from an evolutionary transition involving more than one cell) and the looser coevolutionary interactions that are ubiquitous in ecosystems. Finally, we consider the distributed genome and coevolutionary interactions between genomic entities in the context of early evolution. PMID:26539175

  5. Development of a pulsed uniform supersonic gas expansion system based on an aerodynamic chopper for gas phase reaction kinetic studies at ultra-low temperatures.

    PubMed

    Jiménez, E; Ballesteros, B; Canosa, A; Townsend, T M; Maigler, F J; Napal, V; Rowe, B R; Albaladejo, J

    2015-04-01

    A detailed description of a new pulsed supersonic uniform gas expansion system is presented together with the experimental validation of the setup by applying the CRESU (French acronym for Cinétique de Réaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique to the gas-phase reaction of OH radicals with 1-butene at ca. 23 K and 0.63 millibars of helium (carrier gas). The carrier gas flow, containing negligible mixing ratios of OH-precursor and 1-butene, is expanded from a high pressure reservoir (337 millibars) to a low pressure region (0.63 millibars) through a convergent-divergent nozzle (Laval type). The novelty of this experimental setup is that the uniform supersonic flow is pulsed by means of a Teflon-coated aerodynamic chopper provided with two symmetrical apertures. Under these operational conditions, the designed Laval nozzle achieves a temperature of (22.4 ± 1.4) K in the gas jet. The spatial characterization of the temperature and the total gas density within the pulsed uniform supersonic flow has also been performed by both aerodynamical and spectroscopic methods. The gas consumption with this technique is considerably reduced with respect to a continuous CRESU system. The kinetics of the OH+1-butene reaction was investigated by the pulsed laser photolysis/laser induced fluorescence technique. The rotation speed of the disk is temporally synchronized with the exit of the photolysis and the probe lasers. The rate coefficient (k(OH)) for the reaction under investigation was then obtained and compared with the only available data at this temperature.

  6. A frozen matrix hybrid optical nonlinear system enhanced by a particle lens

    NASA Astrophysics Data System (ADS)

    Chen, Lianwei; Zheng, Xiaorui; Du, Zheren; Jia, Baohua; Gu, Min; Hong, Minghui

    2015-09-01

    In this work, a Graphene Oxide (GO) nano-sheet and SiO2 micro-bead hybrid system based on a frozen matrix was investigated for its enhanced optical nonlinear performance. A frozen matrix is a novel approach that hosts the optical nonlinear nano-particles, which combines the strengths from both liquid and solid phase systems for high performance photonic applications. SiO2 micro-beads were used to induce a local field enhancement effect that improved the optical nonlinearity of GO nano-sheets. The nonlinear performance of the hybrid system is several orders higher than the existing GO nano-sheet liquid dispersion. In addition, this frozen matrix and the local field enhancement effect are two facile and versatile methods that can be applied to many types of nano-particle dispersions.In this work, a Graphene Oxide (GO) nano-sheet and SiO2 micro-bead hybrid system based on a frozen matrix was investigated for its enhanced optical nonlinear performance. A frozen matrix is a novel approach that hosts the optical nonlinear nano-particles, which combines the strengths from both liquid and solid phase systems for high performance photonic applications. SiO2 micro-beads were used to induce a local field enhancement effect that improved the optical nonlinearity of GO nano-sheets. The nonlinear performance of the hybrid system is several orders higher than the existing GO nano-sheet liquid dispersion. In addition, this frozen matrix and the local field enhancement effect are two facile and versatile methods that can be applied to many types of nano-particle dispersions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03304g

  7. High-precision opto-mechanical lens system for space applications assembled by innovative local soldering technique

    NASA Astrophysics Data System (ADS)

    Ribes, P.; Koechlin, C.; Burkhardt, T.; Hornaff, M.; Burkhardt, D.; Kamm, A.; Gramens, S.; Beckert, E.; Fiault, G.; Eberhardt, R.; Tünnermann, A.

    2016-02-01

    Solder joining using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glasses, ceramics and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard taking as input specifications the requirements found for the optical beam expander for the European Space Agency (ESA) EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands; handling high mechanical and thermal loads without losing its optical performances. Finally a high-precision opto-mechanical lens mount has been assembled with a minimal localized stress (<1 MPa) showing outstanding performances in terms of wave-front error measurements and beam depolarization ratio before and after environmental tests.

  8. Quasi-null lens optical system for the fabrication of an oblate convex ellipsoidal mirror: application to the Wide Angle Camera of the Rosetta space mission.

    PubMed

    Pelizzo, Maria-Guglielmina; Da Deppo, Vania; Naletto, Giampiero; Ragazzoni, Roberto; Novi, Andrea

    2006-08-20

    The design of a quasi-null lens system for the fabrication of an aspheric oblate convex ellipsoidal mirror is presented. The Performance and tolerance of the system have been analyzed. The system has been applied successfully for the fabrication of the primary mirror of the Wide Angle Camera (WAC), the imaging system onboard the Rosetta, the European Space Agency cornerstone mission dedicated to the exploration of a comet. The WAC is based on an off-axis two-mirror configuration, in which the primary mirror is an oblate convex ellipsoid with a significant conic constant.

  9. Exploring Teaching Programming Online through Web Conferencing System: The Lens of Activity Theory

    ERIC Educational Resources Information Center

    Çakiroglu, Ünal; Kokoç, Mehmet; Kol, Elvan; Turan, Ebru

    2016-01-01

    The purpose of this qualitative study was to understand activities and behaviors of learners and instructor in an online programming course. Adobe Connect web conferencing system was used as a delivery platform. A total of fifty-six sophomore students attending a computer education and instructional technology program (online) participated in this…

  10. Looking at Graduate Medical Education Through a Different Lens: A Health Care System's Perspective.

    PubMed

    Roemer, Beth M; Azevedo, Theresa; Blumberg, Bruce

    2015-09-01

    In the era of the accountable care organization, U.S. models of physician practice are shifting from the solo, independent practitioner to the physician who is part of a multispecialty group practice or is employed by a health care institution, and from paper-based small offices to practice settings that emphasize technology-enabled, team-based systems of care. In this light, Kaiser Permanente's (KP's) long experience as an integrated, population-based health care delivery system makes it an increasingly relevant model in which to consider how graduate medical education (GME) can best prepare physicians for 21st-century health care. KP's multiple perspectives-as a GME setting, a health care delivery system, a health research enterprise, a community benefit organization, and the nation's largest private, multispecialty group practice of physicians-provide a multifaceted opportunity to consider GME in the context of health care transformation. The authors suggest that all participants in medical education have a role to play in preparing physicians for this future. They recommend that partnerships between universities and health care delivery systems serve as a highly effective model for education; that to better serve the needs of society, medical education institutions must adopt a broad community benefit mindset; and that, when medical groups and other institutions that employ physicians take the baton from GME, they need to commit to ongoing development and lifelong learning to enable their new physicians to reach their full potential.

  11. Using the Lens of Social Capital to Understand Diversity in the Earth System Sciences Workforce

    ERIC Educational Resources Information Center

    Callahan, Caitlin N.; Libarkin, Julie C.; McCallum, Carmen M.; Atchison, Christopher L.

    2015-01-01

    In this commentary, we argue that social capital theory, the idea that membership in a group creates opportunities to acquire valuable information and resources from other group members, is a useful framework in which to consider ways to increase diversity in the Earth System Sciences (ESS) and in the science, technology, engineering, and…

  12. Looking at Graduate Medical Education Through a Different Lens: A Health Care System's Perspective.

    PubMed

    Roemer, Beth M; Azevedo, Theresa; Blumberg, Bruce

    2015-09-01

    In the era of the accountable care organization, U.S. models of physician practice are shifting from the solo, independent practitioner to the physician who is part of a multispecialty group practice or is employed by a health care institution, and from paper-based small offices to practice settings that emphasize technology-enabled, team-based systems of care. In this light, Kaiser Permanente's (KP's) long experience as an integrated, population-based health care delivery system makes it an increasingly relevant model in which to consider how graduate medical education (GME) can best prepare physicians for 21st-century health care. KP's multiple perspectives-as a GME setting, a health care delivery system, a health research enterprise, a community benefit organization, and the nation's largest private, multispecialty group practice of physicians-provide a multifaceted opportunity to consider GME in the context of health care transformation. The authors suggest that all participants in medical education have a role to play in preparing physicians for this future. They recommend that partnerships between universities and health care delivery systems serve as a highly effective model for education; that to better serve the needs of society, medical education institutions must adopt a broad community benefit mindset; and that, when medical groups and other institutions that employ physicians take the baton from GME, they need to commit to ongoing development and lifelong learning to enable their new physicians to reach their full potential. PMID:26177528

  13. 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.

  14. Approach for simultaneous measurement of two-dimensional angular distribution of charged particles. III. Fine focusing of wide-angle beams in multiple lens systems

    NASA Astrophysics Data System (ADS)

    Matsuda, Hiroyuki; Daimon, Hiroshi; Tóth, László; Matsui, Fumihiko

    2007-04-01

    This paper provides a way of focusing wide-angle charged-particle beams in multiple lens systems. In previous papers [H. Matsuda , Phys. Rev. E 71, 066503 (2005); 74, 036501 (2006)], it was shown that an ellipsoidal mesh, combined with electrostatic lenses, enables correction of spherical aberration over wide acceptance angles up to ±60° . In this paper, practical situations where ordinary electron lenses are arranged behind the wide-angle electrostatic lenses are taken into account using ray tracing calculation. For practical realization of the wide-angle lens systems, the acceptance angle is set to ±50° . We note that the output beams of the wide-angle electrostatic lenses have somewhat large divergence angles which cause unacceptable or non-negligible spherical aberration in additional lenses. A solution to this problem is presented showing that lens combinations to cancel spherical aberration are available, whereby wide-angle charged-particle beams can be finely focused with considerably reduced divergence angles less than ±5° .

  15. 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.

  16. Effect of aerodynamic and angle-of-attack uncertainties on the blended entry flight control system of the Space Shuttle from Mach 10 to 2.5

    NASA Technical Reports Server (NTRS)

    Stone, H. W.; Powell, R. W.

    1984-01-01

    A six-degree-of-freedom simulation analysis has been performed for the Space Shuttle Orbiter during entry from Mach 10 to 2.5 with realistic off-nominal conditions using the entry flight control system specified in May 1978. The off-nominal conditions included the following: (1) aerodynamic uncertainties, (2) an error in deriving the angle of attack from onboard instrumentation, (3) the failure of two of the four reaction control-system thrusters on each side, and (4) a lateral center-of-gravity offset. With combinations of the above off-nominal conditions, the control system performed satisfactorily with a few exceptions. The cases that did not exhibit satisfactory performance displayed the following main weaknesses. Marginal performance was exhibited at hypersonic speeds with a sensed angle-of-attack error of 4 deg. At supersonic speeds the system tended to be oscillatory, and the system diverged for several cases because of the inability to hold lateral trim. Several system modifications were suggested to help solve these problems and to maximize safety on the first flight: alter the elevon-trim and speed-brake schedules, delay switching to rudder trim until the rudder effectiveness is adequate, and reduce the overall rudder loop gain. These and other modifications were incorporated in a flight-control-system redesign in May 1979.

  17. Microbiomes: unifying animal and plant systems through the lens of community ecology theory

    PubMed Central

    Christian, Natalie; Whitaker, Briana K.; Clay, Keith

    2015-01-01

    The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant–fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals benefit from greater access to efficient sequencing pipelines and taxonomic reference databases, perhaps due to high medical and veterinary interest. However, researchers studying plant–fungal symbionts benefit from the relative tractability of fungi under laboratory conditions and ease of cultivation. Thus each system has strengths to offer, but both suffer from the lack of a common conceptual framework. We argue that community ecology best illuminates complex species interactions across space and time. In this synthesis we compare and contrast the animal-bacterial and plant–fungal microbiomes using six core theories in community ecology (i.e., succession, community assembly, metacommunities, multi-trophic interactions, disturbance, restoration). The examples and questions raised are meant to spark discussion amongst biologists and lead to the integration of these two systems, as well as more informative, manipulatory experiments on microbiomes research. PMID:26441846

  18. Microbiomes: unifying animal and plant systems through the lens of community ecology theory.

    PubMed

    Christian, Natalie; Whitaker, Briana K; Clay, Keith

    2015-01-01

    The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant-fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals benefit from greater access to efficient sequencing pipelines and taxonomic reference databases, perhaps due to high medical and veterinary interest. However, researchers studying plant-fungal symbionts benefit from the relative tractability of fungi under laboratory conditions and ease of cultivation. Thus each system has strengths to offer, but both suffer from the lack of a common conceptual framework. We argue that community ecology best illuminates complex species interactions across space and time. In this synthesis we compare and contrast the animal-bacterial and plant-fungal microbiomes using six core theories in community ecology (i.e., succession, community assembly, metacommunities, multi-trophic interactions, disturbance, restoration). The examples and questions raised are meant to spark discussion amongst biologists and lead to the integration of these two systems, as well as more informative, manipulatory experiments on microbiomes research.

  19. Applying a global justice lens to health systems research ethics: an initial exploration.

    PubMed

    Pratt, Bridget; Hyder, Adnan A

    2015-03-01

    Recent scholarship has considered what, if anything, rich people owe to poor people to achieve justice in global health and the implications of this for international research. Yet this work has primarily focused on international clinical research. Health systems research is increasingly being performed in low and middle income countries and is essential to reducing global health disparities. This paper provides an initial description of the ethical issues related to priority setting, capacity-building, and the provision of post-study benefits that arise during the conduct of such research. It presents a selection of issues discussed in the health systems research literature and argues that they constitute ethical concerns based on their being inconsistent with a particular theory of global justice (the health capability paradigm). Issues identified include the fact that priority setting for health systems research at the global level is often not driven by national priorities and that capacity-building efforts frequently utilize one-size-fits-all approaches.

  20. Microbiomes: unifying animal and plant systems through the lens of community ecology theory.

    PubMed

    Christian, Natalie; Whitaker, Briana K; Clay, Keith

    2015-01-01

    The field of microbiome research is arguably one of the fastest growing in biology. Bacteria feature prominently in studies on animal health, but fungi appear to be the more prominent functional symbionts for plants. Despite the similarities in the ecological organization and evolutionary importance of animal-bacterial and plant-fungal microbiomes, there is a general failure across disciplines to integrate the advances made in each system. Researchers studying bacterial symbionts in animals benefit from greater access to efficient sequencing pipelines and taxonomic reference databases, perhaps due to high medical and veterinary interest. However, researchers studying plant-fungal symbionts benefit from the relative tractability of fungi under laboratory conditions and ease of cultivation. Thus each system has strengths to offer, but both suffer from the lack of a common conceptual framework. We argue that community ecology best illuminates complex species interactions across space and time. In this synthesis we compare and contrast the animal-bacterial and plant-fungal microbiomes using six core theories in community ecology (i.e., succession, community assembly, metacommunities, multi-trophic interactions, disturbance, restoration). The examples and questions raised are meant to spark discussion amongst biologists and lead to the integration of these two systems, as well as more informative, manipulatory experiments on microbiomes research. PMID:26441846

  1. Viewing the Kenyan health system through an equity lens: implications for universal coverage

    PubMed Central

    2011-01-01

    Introduction Equity and universal coverage currently dominate policy debates worldwide. Health financing approaches are central to universal coverage. The way funds are collected, pooled, and used to purchase or provide services should be carefully considered to ensure that population needs are addressed under a universal health system. The aim of this paper is to assess the extent to which the Kenyan health financing system meets the key requirements for universal coverage, including income and risk cross-subsidisation. Recommendations on how to address existing equity challenges and progress towards universal coverage are made. Methods An extensive review of published and gray literature was conducted to identify the sources of health care funds in Kenya. Documents were mainly sourced from the Ministry of Medical Services and the Ministry of Public Health and Sanitation. Country level documents were the main sources of data. In cases where data were not available at the country level, they were sought from the World Health Organisation website. Each financing mechanism was analysed in respect to key functions namely, revenue generation, pooling and purchasing. Results The Kenyan health sector relies heavily on out-of-pocket payments. Government funds are mainly allocated through historical incremental approach. The sector is largely underfunded and health care contributions are regressive (i.e. the poor contribute a larger proportion of their income to health care than the rich). Health financing in Kenya is fragmented and there is very limited risk and income cross-subsidisation. The country has made little progress towards achieving international benchmarks including the Abuja target of allocating 15% of government's budget to the health sector. Conclusions The Kenyan health system is highly inequitable and policies aimed at promoting equity and addressing the needs of the poor and vulnerable have not been successful. Some progress has been made towards

  2. A Collaborative Analysis Tool for Integrated Hypersonic Aerodynamics, Thermal Protection Systems, and RBCC Engine Performance for Single Stage to Orbit Vehicles

    NASA Technical Reports Server (NTRS)

    Stanley, Thomas Troy; Alexander, Reginald; Landrum, Brian

    2000-01-01

    engine model. HYFIM performs the aerodynamic analysis of forebodies and inlet characteristics of RBCC powered SSTO launch vehicles. HYFIM is applicable to the analysis of the ramjet/scramjet engine operations modes (Mach 3-12), and provides estimates of parameters such as air capture area, shock-on-lip Mach number, design Mach number, compression ratio, etc., based on a basic geometry routine for modeling axisymmetric cones, 2-D wedge geometries. HYFIM also estimates the variation of shock layer properties normal to the forebody surface. The thermal protection system (TPS) is directly linked to determination of the vehicle moldline and the shaping of the trajectory. Thermal protection systems to maintain the structural integrity of the vehicle must be able to mitigate the heat transfer to the structure and be lightweight. Herein lies the interdependency, in that as the vehicle's speed increases, the TPS requirements are increased. And as TPS masses increase the effect on the propulsion system and all other systems is compounded. The need to analyze vehicle forebody and engine inlet is critical to be able to design the RBCC vehicle. To adequately determine insulation masses for an RBCC vehicle, the hypersonic aerodynamic environment and aeroheating loads must be calculated and the TPS thicknesses must be calculated for the entire vehicle. To accomplish this an ascent or reentry trajectory is obtained using the computer code Program to Optimize Simulated Trajectories (POST). The trajectory is then used to calculate the convective heat rates on several locations on the vehicles using the Miniature Version of the JA70 Aerodynamic Heating Computer Program (MINIVER). Once the heat rates are defined for each body point on the vehicle, then insulation thicknesses that are required to maintain the vehicle within structural limits are calculated using Systems Improved Numerical Differencing Analyzer (SINDA) models. If the TPS masses are too heavy for the performance of the vehicle

  3. 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.

  4. Advanced aerodynamics and active controls. Selected NASA research

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Aerodynamic and active control concepts for application to commercial transport aircraft are discussed. Selected topics include in flight direct strike lightning research, triply redundant digital fly by wire control systems, tail configurations, winglets, and the drones for aerodynamic and structural testing (DAST) program.

  5. FLPP IXV Re-Entry Vehicle, Aerodynamic Characterisation

    NASA Astrophysics Data System (ADS)

    Belmont, J.-P.; Cantinaud, O.; Tribot, J.-P.; Walloschek, T.

    2009-01-01

    The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues, while supporting the future generation launchers and improving in general European capabilities in the strategic field of atmospheric re-entry for space transportation, exploration, and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on- ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re- entry system, integrating the critical re-entry technologies at the system level. The current IXV vehicle is a slender body type exhibiting rounded shape and thick body. Since the beginning of the IXV project, an aerodynamic data base (AEDB) has been built up and continuously updated integrating the additional information mainly provided by means of CFD. The AEDB includes nominal aerodynamic data, a new set of free molecular aerodynamic coefficients as well as aerodynamic uncertainties. Through the phase B2/C1, complementary computations were performed (CFSE, EPFL, ASTRIUM, TAS, DAA) as well as wind tunnel tests such as ONERA S4ma, DLR H2K, DNW/NLR SST, FOI T1500. All data were analyzed and compared enabling the consolidation of the nominal aerodynamic and aerodynamic uncertainties as well. The paper presents the logic of work based on the system engineering plan with emphasis on the different prediction tools used aiming the final aerodynamic characterization of the IXV configuration.

  6. Toward the design of a motion-free tunable coupling module for varying spatial beam profiles: foundations of optimal coupling of a Gaussian mode into a fiber collimator with a dynamic two-lens system.

    PubMed

    Qasim, Muhammad; Reza, Syed Azer

    2015-11-01

    In this paper, we present analytical expressions for the coupling of the fundamental Gaussian mode into a fiber collimator (FC) using a two-lens system. For this two-lens system, we also derive the limiting condition imposed on the focal lengths of the two individual lenses and their mutual separation for near-to-perfect mode coupling into the FC. Variations in the spatial mode profile of a Gaussian beam may occur due to various reasons. These include controlled changes in the beam profile inside mode-division multiplexed systems, and undesired spatial profile variations in beams that pass through turbulent media. The necessity of a dynamic mode-coupling module is dictated by the need to optimally couple Gaussian beams with dynamically changing spatial profiles. Using the analytical expressions derived for mode-coupling efficiency and the resulting lens separation condition that is imposed on a two-lens coupling system, we propose the design of a dynamic two-lens mode-coupling system with a pair of electronically controlled tunable lenses. The proposed dynamic coupling module is motion free and involves the movement of bulk components in order to achieve optimal coupling. The experimental results are also presented to verify the theoretical claims and the working principle of a two-lens mode-coupling system. The results of the experiments are discussed in detail and an excellent agreement is demonstrated between the proposed theoretical framework and the experimental results. PMID:26560578

  7. The SNAP Strong Lens Survey

    SciTech Connect

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  8. Liquid crystal Fresnel lens display

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Qian; Abhishek Kumar, Srivastava; Alwin Tam, Ming-Wai; Zheng, Zhi-Gang; Shen, Dong; Vladimir, Chigrinov G.; Kwok, Hoi-Sing

    2016-09-01

    A novel see-through display with a liquid crystal lens array was proposed. A liquid crystal Fresnel lens display (LCFLD) with a holographic screen was demonstrated. The proposed display system has high efficiency, simple fabrication, and low manufacturing cost due to the absence of a polarizer and color filter. Project supported by Partner State Key Laboratory on Advanced Displays and Optoelectronics Technologies HKUST, China, the National Natural Science Foundation of China (Grant Nos. 61435008 and 61575063), and the Fundamental Research Funds for the Central Universities, China (Grant No. WM1514036).

  9. Liquid crystal Fresnel lens display

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Qian; Abhishek Kumar, Srivastava; Alwin Tam, Ming-Wai; Zheng, Zhi-Gang; Shen, Dong; Vladimir, Chigrinov G.; Kwok, Hoi-Sing

    2016-09-01

    A novel see-through display with a liquid crystal lens array was proposed. A liquid crystal Fresnel lens display (LCFLD) with a holographic screen was demonstrated. The proposed display system has high efficiency, simple fabrication, and low manufacturing cost due to the absence of a polarizer and color filter. Project supported by Partner State Key Laboratory on Advanced Displays and Optoelectronics Technologies HKUST, China, the National Natural Science Foundation of China (Grant Nos. 61435008 and 61575063), and the Fundamental Research Funds for the Central Universities, China (Grant No. WM1514036).

  10. Mental Health Reform at a Systems Level: Widening the Lens on Recovery-Oriented Care

    PubMed Central

    Kidd, Sean A; McKenzie, Kwame J; Virdee, Gursharan

    2014-01-01

    This paper is an initial attempt to collate the literature on psychiatric inpatient recovery-based care and, more broadly, to situate the inpatient care sector within a mental health reform dialogue that, to date, has focused almost exclusively on outpatient and community practices. We make the argument that until an evidence base is developed for recovery-oriented practices on hospital wards, the effort to advance recovery-oriented systems will stagnate. Our scoping review was conducted in line with the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (commonly referred to as PRISMA) guidelines. Among the 27 papers selected for review, most were descriptive or uncontrolled outcome studies. Studies addressing strategies for improving care quality provide some modest evidence for reflective dialogue with former inpatient clients, role play and mentorship, and pairing general training in recovery oriented care with training in specific interventions, such as Illness Management and Recovery. Relative to some other fields of medicine, evidence surrounding the question of recovery-oriented care on psychiatric wards and how it may be implemented is underdeveloped. Attention to mental health reform in hospitals is critical to the emergence of recovery-oriented systems of care and the realization of the mandate set forward in the Mental Health Strategy for Canada. PMID:25007277

  11. Automatic Element Addition and Deletion in Lens Optimization

    NASA Astrophysics Data System (ADS)

    Cheng, Xuemin; Wang, Yongtian; Hao, Qun; Sasian, Jose

    2003-03-01

    A mechanism is established for the automatic addition and deletion of optical elements during the course of lens optimization. Two lens-form parameters, quantifying the symmetry of the optical system and the optical-power distribution among the individual lens elements, are used as criteria in this automatic procedure. Design examples are provided that demonstrate the practicability of the scheme.

  12. High resolution iridocorneal angle imaging system by axicon lens assisted gonioscopy.

    PubMed

    Perinchery, Sandeep Menon; Shinde, Anant; Fu, Chan Yiu; Jeesmond Hong, Xun Jie; Baskaran, Mani; Aung, Tin; Murukeshan, Vadakke Matham

    2016-01-01

    Direct visualization and assessment of the iridocorneal angle (ICA) region with high resolution is important for the clinical evaluation of glaucoma. However, the current clinical imaging systems for ICA do not provide sufficient structural details due to their poor resolution. The key challenges in achieving high quality ICA imaging are its location in the anterior region of the eye and the occurrence of total internal reflection due to refractive index difference between cornea and air. Here, we report an indirect axicon assisted gonioscopy imaging probe with white light illumination. The illustrated results with this probe shows significantly improved visualization of structures in the ICA including TM region, compared to the current available tools. It could reveal critical details of ICA and expected to aid management by providing information that is complementary to angle photography and gonioscopy. PMID:27471000

  13. High resolution iridocorneal angle imaging system by axicon lens assisted gonioscopy

    PubMed Central

    Perinchery, Sandeep Menon; Shinde, Anant; Fu, Chan Yiu; Jeesmond Hong, Xun Jie; Baskaran, Mani; Aung, Tin; Murukeshan, Vadakke Matham

    2016-01-01

    Direct visualization and assessment of the iridocorneal angle (ICA) region with high resolution is important for the clinical evaluation of glaucoma. However, the current clinical imaging systems for ICA do not provide sufficient structural details due to their poor resolution. The key challenges in achieving high quality ICA imaging are its location in the anterior region of the eye and the occurrence of total internal reflection due to refractive index difference between cornea and air. Here, we report an indirect axicon assisted gonioscopy imaging probe with white light illumination. The illustrated results with this probe shows significantly improved visualization of structures in the ICA including TM region, compared to the current available tools. It could reveal critical details of ICA and expected to aid management by providing information that is complementary to angle photography and gonioscopy. PMID:27471000

  14. Networked Community Change: Understanding Community Systems Change through the Lens of Social Network Analysis.

    PubMed

    Lawlor, Jennifer A; Neal, Zachary P

    2016-06-01

    Addressing complex problems in communities has become a key area of focus in recent years (Kania & Kramer, 2013, Stanford Social Innovation Review). Building on existing approaches to understanding and addressing problems, such as action research, several new approaches have emerged that shift the way communities solve problems (e.g., Burns, 2007, Systemic Action Research; Foth, 2006, Action Research, 4, 205; Kania & Kramer, 2011, Stanford Social Innovation Review, 1, 36). Seeking to bring clarity to the emerging literature on community change strategies, this article identifies the common features of the most widespread community change strategies and explores the conditions under which such strategies have the potential to be effective. We identify and describe five common features among the approaches to change. Then, using an agent-based model, we simulate network-building behavior among stakeholders participating in community change efforts using these approaches. We find that the emergent stakeholder networks are efficient when the processes are implemented under ideal conditions. PMID:27221668

  15. High resolution iridocorneal angle imaging system by axicon lens assisted gonioscopy.

    PubMed

    Perinchery, Sandeep Menon; Shinde, Anant; Fu, Chan Yiu; Jeesmond Hong, Xun Jie; Baskaran, Mani; Aung, Tin; Murukeshan, Vadakke Matham

    2016-01-01

    Direct visualization and assessment of the iridocorneal angle (ICA) region with high resolution is important for the clinical evaluation of glaucoma. However, the current clinical imaging systems for ICA do not provide sufficient structural details due to their poor resolution. The key challenges in achieving high quality ICA imaging are its location in the anterior region of the eye and the occurrence of total internal reflection due to refractive index difference between cornea and air. Here, we report an indirect axicon assisted gonioscopy imaging probe with white light illumination. The illustrated results with this probe shows significantly improved visualization of structures in the ICA including TM region, compared to the current available tools. It could reveal critical details of ICA and expected to aid management by providing information that is complementary to angle photography and gonioscopy.

  16. Networked Community Change: Understanding Community Systems Change through the Lens of Social Network Analysis.

    PubMed

    Lawlor, Jennifer A; Neal, Zachary P

    2016-06-01

    Addressing complex problems in communities has become a key area of focus in recent years (Kania & Kramer, 2013, Stanford Social Innovation Review). Building on existing approaches to understanding and addressing problems, such as action research, several new approaches have emerged that shift the way communities solve problems (e.g., Burns, 2007, Systemic Action Research; Foth, 2006, Action Research, 4, 205; Kania & Kramer, 2011, Stanford Social Innovation Review, 1, 36). Seeking to bring clarity to the emerging literature on community change strategies, this article identifies the common features of the most widespread community change strategies and explores the conditions under which such strategies have the potential to be effective. We identify and describe five common features among the approaches to change. Then, using an agent-based model, we simulate network-building behavior among stakeholders participating in community change efforts using these approaches. We find that the emergent stakeholder networks are efficient when the processes are implemented under ideal conditions.

  17. Three-shell-based lens barrel for the effective athermalization of an IR optical system.

    PubMed

    Yang, Ho-Soon; Kihm, Hagyong; Moon, Il Kweon; Jung, Gil-Jae; Choi, Se-Chol; Lee, Kyung-Joo; Hwang, Hong-Yeon; Kim, Sug-Whan; Lee, Yun-Woo

    2011-11-20

    We have developed a new IR optical system that consists of three mirrors and four lenses, and that operates in the temperature range 8°C-32°C. This temperature range can induce thermoelastic deformation in the lenses and their mounting subassembly, leading to a large defocus error associated with the displacement of the lenses inside the barrel. We suggest using a new three-shell-based athermalization structure composed of two materials with different coefficients of thermal expansion (Invar and aluminum). A finite element analysis and the experiment data were used to confirm that this new athermalization barrel had a defocus error sensitivity of 11.6 nm/°C; this is an improvement on the widely used conventional single-shell titanium barrel model, which has a defocus error sensitivity of 29.8 nm/°C. This paper provides the technical details of the new athermalization design, and its computational and experimental performance results. PMID:22108878

  18. Fiber-optic-based laser vapor screen flow visualization system for aerodynamic research in larger scale subsonic and transonic wind tunnels

    NASA Technical Reports Server (NTRS)

    Erickson, Gary E.; Inenaga, Andrew S.

    1994-01-01

    Laser vapor screen (LVS) flow visualization systems that are fiber-optic based were developed and installed for aerodynamic research in the Langley 8-Foot Transonic Pressure Tunnel and the Langley 7- by 10-Foot High Speed Tunnel. Fiber optics are used to deliver the laser beam through the plenum shell that surrounds the test section of each facility and to the light-sheet-generating optics positioned in the ceiling window of the test section. Water is injected into the wind tunnel diffuser section to increase the relative humidity and promote condensation of the water vapor in the flow field about the model. The condensed water vapor is then illuminated with an intense sheet of laser light to reveal features of the flow field. The plenum shells are optically sealed; therefore, video-based systems are used to observe and document the flow field. Operational experience shows that the fiber-optic-based systems provide safe, reliable, and high-quality off-surface flow visualization in smaller and larger scale subsonic and transonic wind tunnels. The design, the installation, and the application of the Langley Research Center (LaRC) LVS flow visualization systems in larger scale wind tunnels are highlighted. The efficiency of the fiber optic LVS systems and their insensitivity to wind tunnel vibration, the tunnel operating temperature and pressure variations, and the airborne contaminants are discussed.

  19. Meta-analysis of the ocular biocompatibility of a new multipurpose lens care system

    PubMed Central

    Reindel, William; Merchea, Mohinder M; Rah, Marjorie J; Zhang, Lening

    2013-01-01

    Background The purpose of this paper is to evaluate the biocompatibility of a novel multipurpose solution (MPS) with a dual disinfectant system containing polyaminopropyl biguanide and polyquaternium-1 (Biotrue®) by analysis of biomicroscopy signs and adverse events in six large clinical trials. Methods Data from six consecutive, prospective clinical trials conducted from February 2008 to March 2010 were combined for meta-analysis. Subjects used the new MPS daily for periods of 2 weeks to 6 months. Slit-lamp signs were graded at each follow-up visit using an ordinal scale (0, one; 1, trace; 2, mild; 3, moderate; 4, severe). Analysis for biocompatibility included tracking of greater than grade 2 slit-lamp findings and number of adverse events. Results A total of 1,567 subjects (3,134 eyes) and 81 clinical investigators participated in the six studies, with 1,499 subjects completing the studies. Based on subject days in the studies, there were 72,904 exposures to the MPS and 7,212 biomicroscopy examinations. The completion rate for the studies was 96.3%. Per observation incidence of any finding greater than grade 2 at the follow-up visits were: corneal staining 0.08%, limbal injection 0.04%, bulbar injection 0.04%, tarsal conjunctiva abnormality 0.09%, and neovascularization 0.01%. There were no other slit-lamp signs greater than grade 2 and no statistically significant difference between hydrogels and silicone hydrogels for any finding. There were no reports of adverse events during the trials. Conclusion Analysis of over 72,000 daily exposures and 7,212 eye examinations showed that the novel MPS exhibited excellent biocompatibility in subjects using daily wear hydrogel or silicone hydrogel lenses. PMID:24143073

  20. 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.

  1. Aerodynamic analysis of a tumbling American football

    NASA Astrophysics Data System (ADS)

    Hare, Daniel Edmundson

    In this study, the aerodynamic effects on an American football are characterized, especially in a tumbling, or end-over-end, motion as seen in a typical kickoff or field goal attempt. The objective of this study is to establish aerodynamic coefficients for the dynamic motion of a tumbling American football. A subsonic wind tunnel was used to recreate a range of air velocities that, when coupled with rotation rates and differing laces orientations, would provide a test bed for aerodynamic drag, side, and lift coefficient analysis. Test results quantify effect of back-spin and top-spin on lift force. Results show that the presence of laces imposes a side force in the opposite direction of the laces orientation. A secondary system was installed to visualize air flow around the tumbling ball and record high-speed video of wake patterns, as a qualitative check of measured force directions.

  2. Aerodynamic Performance of Electro-Active Membrane Wings

    NASA Astrophysics Data System (ADS)

    Barbu, Ioan-Alexandru; de Kat, Roeland; Ganapathisubramani, Bharathram

    2014-11-01

    Electro-active polymers offer due to their multivariate compliant nature a great potential for integrating the lift producing system and the control system into one. This work presents the first step in describing both the mechanical and aerodynamic performance of such materials and focuses on both understanding their behaviour in aerodynamic applications and on analysing their aerodynamic performance. Photogrammetry and load measurements are conducted in a wind tunnel for both silicone-based and acrylic-based membranes at zero prestrain supported in a perimeter reinforced frame in electrically passive, active and pulsing conditions. A wide range of fixed voltages and pulsing frequencies are considered. Due to their hyper-viscoelastic nature, both short and long term hysteresis analysis are conducted in terms of aerodynamic performance. Along with these tests, analyses of the effects of the percentage electrode area and silicone content on aerodynamic performance are conducted.

  3. An Essential Role for FGF Receptor Signaling in Lens Development

    PubMed Central

    Robinson, Michael L.

    2007-01-01

    Since the days of Hans Spemann, the ocular lens has served as one of the most important developmental systems for elucidating fundamental processes of induction and differentiation. More recently, studies in the lens have contributed significantly to our understanding of cell cycle regulation and apoptosis. Over twenty years of accumulated evidence using several different vertebrate species has suggested that fibroblast growth factors (FGFs) and/or fibroblast growth factor receptors (FGFRs) play a key role in lens development. FGFR signaling has been implicated in lens induction, lens cell proliferation and survival, lens fiber differentiation and lens regeneration. Here we will review and discuss historical and recent evidence suggesting that (FGFR) signaling plays a vital and universal role in multiple aspects of lens development. PMID:17116415

  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. Rarefied-flow aerodynamics

    NASA Technical Reports Server (NTRS)

    Potter, J. Leith

    1992-01-01

    Means for relatively simple and quick procedures are examined for estimating aerodynamic coefficients of lifting reentry vehicles. The methods developed allow aerospace designers not only to evaluate the aerodynamics of specific shapes but also to optimize shapes under given constraints. The analysis was also studied of the effect of thermomolecular flow on pressures measured by an orifice near the nose of a Space Shuttle Orbiter at altitudes above 75 km. It was shown that pressures corrected for thermomolecular flow effect are in good agreement with values predicted by independent theoretical methods. An incidental product was the insight gained about the free molecular thermal accommodation coefficient applicable under 'real' conditions of high speed flow in the Earth's atmosphere. The results are presented as abstracts of referenced papers. One reference paper is presented in its entirety.

  6. 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.

  7. Aerodynamic Design of Axial Flow Compressors

    NASA Technical Reports Server (NTRS)

    Bullock, R. O. (Editor); Johnsen, I. A.

    1965-01-01

    An overview of 'Aerodynamic systems design of axial flow compressors' is presented. Numerous chapters cover topics such as compressor design, ptotential and viscous flow in two dimensional cascades, compressor stall and blade vibration, and compressor flow theory. Theoretical aspects of flow are also covered.

  8. User's guide to program FLEXSTAB. [aerodynamics

    NASA Technical Reports Server (NTRS)

    Cavin, R. K., III; Colunga, D.

    1975-01-01

    A manual is presented for correctly submitting program runs in aerodynamics on the UNIVAC 1108 computer system. All major program modules are included. Control cards are documented for the user's convenience, and card parameters are included in order to provide some idea as to reasonable time estimates for the program modules.

  9. Aerodynamic noise sources

    NASA Astrophysics Data System (ADS)

    Munin, A. G.; Kuznetsov, V. M.; Leontev, E. A.

    A general theory is developed for aerodynamic sound generation and its propagation in an inhomogeneous medium. Results of theoretical and experimental studies of the acoustic characteristics of jets are discussed, and a solution is presented to the problem concerning the noise from a section, free rotor, and a rotor located inside a channel. Sound propagation in a channel with flow and selection of soundproofing liners for the channel walls are also discussed.

  10. Canine amino acid transport system Xc(-): cDNA sequence, distribution and cystine transport activity in lens epithelial cells.

    PubMed

    Maruo, Takuya; Kanemaki, Nobuyuki; Onda, Ken; Sato, Reiichiro; Ichihara, Nobuteru; Ochiai, Hideharu

    2014-04-01

    The cystine transport activity of a lens epithelial cell line originated from a canine mature cataract was investigated. The distinct cystine transport activity was observed, which was inhibited to 28% by extracellular 1 mM glutamate. The cDNA sequences of canine cysteine/glutamate exchanger (xCT) and 4F2hc were determined. The predicted amino acid sequences were 527 and 533 amino acid polypeptides, respectively. The amino acid sequences of canine xCT and 4F2hc showed high similarities (>80%) to those of humans. The expression of xCT in lens epithelial cell line was confirmed by western blot analysis. RT-PCR analysis revealed high level expression only in the brain, and it was below the detectable level in other tissues.

  11. 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.

  12. Gravitational Lens B0218+357

    NASA Video Gallery

    This movie illustrates the components of a gravitational lens system (a kind of natural telescope formed when a rare cosmic alignment allows the gravity of a massive object to bend and amplify ligh...

  13. Lens Design Using Group Indices of Refraction

    NASA Technical Reports Server (NTRS)

    Vaughan, A. H.

    1995-01-01

    An approach to lens design is described in which the ratio of the group velocity to the speed of light (the group index) in glass is used, in conjunction with the more familiar phase index of refraction, to control certain chromatic properties of a system of thin lenses in contact. The first-order design of thin-lens systems is illustrated by examples incorporating the methods described.

  14. 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

  15. 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.

  16. On cup anemometer rotor aerodynamics.

    PubMed

    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.

  17. Singlet mega-pixel resolution lens

    NASA Astrophysics Data System (ADS)

    Lin, Chen-Hung; Lin, Hoang Yan; Chang, Horng

    2008-03-01

    There always exist some new challenges for lens designers to keep their old-line technology update. To minimize lens volume is one of the most notified examples. In this paper we designed a single thick lens, constructed by using one oblique (reflective) surface, apart from two conventional refractive surfaces, to bend the optical path of the optical system to achieve this goal. Detail design procedure, including system layout and lens performance diagrams, will be presented. Following the first order layout, we applied aspherical form to the two refractive surfaces in order to correct the spherical aberration up to an acceptable condition. Then, the reduced aberrations such as coma, astigmatism, field curvature and distortion can easily be corrected with some calculations related to spherical aberration as shown in the publication of H. H. Hopkins (1950). Plastic material is used in the design, because the aspherical surfaces can then be manufactured in a more cost effective way. The final specification of the design is: EFL is 4.6 mm, the F number is 2.8, the over all thickness of lens is 3.6 mm, its MTF is 0.3 at 227 lp/mm in center field and chief ray angle is less than 15 degrees. Lens data as well as optical performance curves are also presented in the paper. In conclusion we have successfully finished a mega-pixel resolution lens design and its overall thickness is compatible with the state of the art.

  18. Structural Conditions for Collaboration and Learning in Innovation Networks: Using an Innovation System Performance Lens to Analyse Agricultural Knowledge Systems

    ERIC Educational Resources Information Center

    Hermans, Frans; Klerkx, Laurens; Roep, Dirk

    2015-01-01

    Purpose: We investigate how the structural conditions of eight different European agricultural innovation systems can facilitate or hinder collaboration and social learning in multidisciplinary innovation networks. Methodology: We have adapted the Innovation System Failure Matrix to investigate the main barriers and enablers eight countries…

  19. Electrowetting based infrared lens using ionic liquids

    NASA Astrophysics Data System (ADS)

    Hu, Xiaodong; Zhang, Shiguo; Liu, Yu; Qu, Chao; Lu, Liujin; Ma, Xiangyuan; Zhang, Xiaoping; Deng, Youquan

    2011-11-01

    We demonstrated an infrared variable focus ionic liquids lens using electrowetting, which could overcome the problems caused by use of water, e.g., evaporation and poor thermostability, while keeping good optical transparency in visible light and near-infrared region. Besides, the type of lens (convex or concave) could be tuned by applied voltage or refractive index of ILs used, and the transmittance was measured to exceed 90% over the spectrum of visible light and near-infrared. We believe this infrared variable focus ionic liquids lens has a great application prospect in both visible light and infrared image systems.

  20. Development of a tantalum pentoxide Luneberg lens

    NASA Technical Reports Server (NTRS)

    Bryan, D. A.; Chubb, C. R.; Powers, J. K.; Reed, W. R.; Dalke, E. A.; Tomaschke, H. E.

    1982-01-01

    A process has been developed for the fabrication of a tantalum pentoxide waveguide Luneburg lens as the input collimator for an optical signal processing circuit on a silicon substrate, such as an integrated wavelength demultiplexer. The development of such a lens involved improvement of the deposition mask profile, reduction of surface scattering by underlaying the lens, reduction of edge scattering by using shims under the mask, and prediction and measurement of the TE-TM polarization aberration. It is shown that polarization aberration significantly affects the design of a demultiplexer system.

  1. Model aerodynamic test results for two variable cycle engine coannular exhaust systems at simulated takeoff and cruise conditions. Comprehensive data report. Volume 2: Tabulated aeroynamic data book 1

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.

    1981-01-01

    Tabulated data from wind tunnel tests conducted to evaluate the aerodynamic performance of an advanced coannular exhaust nozzle for a future supersonic propulsion system are presented. Tests were conducted with two test configurations: (1) a short flap mechanism for fan stream control with an isentropic contoured flow splitter, and (2) an iris fan nozzle with a conical flow splitter. Both designs feature a translating primary plug and an auxiliary inlet ejector. Tests were conducted at takeoff and simulated cruise conditions. Data were acquired at Mach numbers of 0, 0.36, 0.9, and 2.0 for a wide range of nozzle operating conditions. At simulated supersonic cruise, both configurations demonstrated good performance, comparable to levels assumed in earlier advanced supersonic propulsion studies. However, at subsonic cruise, both configurations exhibited performance that was 6 to 7.5 percent less than the study assumptions. At takeoff conditions, the iris configuration performance approached the assumed levels, while the short flap design was 4 to 6 percent less. Data are provided through test run 25.

  2. Model aerodynamic test results for two variable cycle engine coannular exhaust systems at simulated takeoff and cruise conditions. [Lewis 8 by 6-foot supersonic wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.

    1980-01-01

    Wind tunnel tests were conducted to evaluate the aerodynamic performance of a coannular exhaust nozzle for a proposed variable stream control supersonic propulsion system. Tests were conducted with two simulated configurations differing primarily in the fan duct flowpaths: a short flap mechanism for fan stream control with an isentropic contoured flow splitter, and an iris fan nozzle with a conical flow splitter. Both designs feature a translating primary plug and an auxiliary inlet ejector. Tests were conducted at takeoff and simulated cruise conditions. Data were acquired at Mach numbers of 0, 0.36, 0.9, and 2.0 for a wide range of nozzle operating conditions. At simulated supersonic cruise, both configurations demonstrated good performance, comparable to levels assumed in earlier advanced supersonic propulsion studies. However, at subsonic cruise, both configurations exhibited performance that was 6 to 7.5 percent less than the study assumptions. At take off conditions, the iris configuration performance approached the assumed levels, while the short flap design was 4 to 6 percent less.

  3. A title-gap flow model for use in aerodynamic loads assessment of space shuttle thermal protection system: Parallel gap faces

    NASA Technical Reports Server (NTRS)

    Dwoyer, D. L.; Newman, P. A.; Thames, F. C.; Melson, N. D.

    1981-01-01

    The problem of predicting aerodynamic loads on the insulating tiles of the space shuttle thermal protection system (TPS) is discussed and seen to require a method for predicting pressure and mass flux in the gaps between tiles. A mathematical model of the tile-gap flow is developed, based upon a slow viscous (Stokes) flow analysis, and is verified against experimental data. The tile-gap pressure field is derived from a solution of the two-dimensional Laplace equation; the mass-flux vector is then calculated from the pressure gradient. The means for incorporating this model into a lumped-parameter network analogy for porous-media flow is given. The means for incorporating this model into a lumped-parameter network analogy for porous-media flow is given. The flow model shows tile-gap mass flux to be very sensitive to the gap width indicating a need for coupling the TPS flow and tile displacement calculation. Analytical and experimental work to improve TPS flow predictions and a possible shuttle TPS hardware modification are recommended.

  4. Tail contribution to the directional aerodynamic characteristics of a 1/6-scale model of the rotor systems research aircraft with a tail rotor

    NASA Technical Reports Server (NTRS)

    Mineck, R. E.

    1977-01-01

    The results are presented of a wind tunnel investigation to determine the tail contribution to the directional aerodynamic characteristics of a 1/6-scale model of the rotor systems research aircraft (RSRA) with a tail rotor. No main rotor was used during the investigation. Data were obtained with and without the tail rotor over a range of sideslip angle and over a range of rotor collective pitch angle. The model with the tail rotor was tested at several advance ratios with and without thrust from the auxiliary thrust engines on the RSRA fuselage. Increasing the space between the tail-rotor hub and the vertical tail reduced the tail-rotor torque required at moderate to high rotor thrust. Increasing the exit dynamic pressure of the auxiliary thrust engines decreases the tail contribution to the static directional stability. The tail-rotor thrust and its interference provide a positive increment to the static directional stability. The tail contribution increases with forward speed. The adverse yawing moment of the airframe would strongly affect the thrust required of the tail rotor when the helicopter is hovering in a crosswind.

  5. TAD- THEORETICAL AERODYNAMICS PROGRAM

    NASA Technical Reports Server (NTRS)

    Barrowman, J.

    1994-01-01

    This theoretical aerodynamics program, TAD, was developed to predict the aerodynamic characteristics of vehicles with sounding rocket configurations. These slender, axisymmetric finned vehicle configurations have a wide range of aeronautical applications from rockets to high speed armament. Over a given range of Mach numbers, TAD will compute the normal force coefficient derivative, the center-of-pressure, the roll forcing moment coefficient derivative, the roll damping moment coefficient derivative, and the pitch damping moment coefficient derivative of a sounding rocket configured vehicle. The vehicle may consist of a sharp pointed nose of cone or tangent ogive shape, up to nine other body divisions of conical shoulder, conical boattail, or circular cylinder shape, and fins of trapezoid planform shape with constant cross section and either three or four fins per fin set. The characteristics computed by TAD have been shown to be accurate to within ten percent of experimental data in the supersonic region. The TAD program calculates the characteristics of separate portions of the vehicle, calculates the interference between separate portions of the vehicle, and then combines the results to form a total vehicle solution. Also, TAD can be used to calculate the characteristics of the body or fins separately as an aid in the design process. Input to the TAD program consists of simple descriptions of the body and fin geometries and the Mach range of interest. Output includes the aerodynamic characteristics of the total vehicle, or user-selected portions, at specified points over the mach range. The TAD program is written in FORTRAN IV for batch execution and has been implemented on an IBM 360 computer with a central memory requirement of approximately 123K of 8 bit bytes. The TAD program was originally developed in 1967 and last updated in 1972.

  6. Comparisons of several aerodynamic methods for application to dynamic loads analyses

    NASA Technical Reports Server (NTRS)

    Kroll, R. I.; Miller, R. D.

    1976-01-01

    The results of a study are presented in which the applicability at subsonic speeds of several aerodynamic methods for predicting dynamic gust loads on aircraft, including active control systems, was examined and compared. These aerodynamic methods varied from steady state to an advanced unsteady aerodynamic formulation. Brief descriptions of the structural and aerodynamic representations and of the motion and load equations are presented. Comparisons of numerical results achieved using the various aerodynamic methods are shown in detail. From these results, aerodynamic representations for dynamic gust analyses are identified. It was concluded that several aerodynamic methods are satisfactory for dynamic gust analyses of configurations having either controls fixed or active control systems that primarily affect the low frequency rigid body aircraft response.

  7. Aerodynamic drag in cycling: methods of assessment.

    PubMed

    Debraux, Pierre; Grappe, Frederic; Manolova, Aneliya V; Bertucci, William

    2011-09-01

    When cycling on level ground at a speed greater than 14 m/s, aerodynamic drag is the most important resistive force. About 90% of the total mechanical power output is necessary to overcome it. Aerodynamic drag is mainly affected by the effective frontal area which is the product of the projected frontal area and the coefficient of drag. The effective frontal area represents the position of the cyclist on the bicycle and the aerodynamics of the cyclist-bicycle system in this position. In order to optimise performance, estimation of these parameters is necessary. The aim of this study is to describe and comment on the methods used during the last 30 years for the evaluation of the effective frontal area and the projected frontal area in cycling, in both laboratory and actual conditions. Most of the field methods are not expensive and can be realised with few materials, providing valid results in comparison with the reference method in aerodynamics, the wind tunnel. Finally, knowledge of these parameters can be useful in practice or to create theoretical models of cycling performance.

  8. 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.

  9. 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.

  10. Aerodynamics of high frequency flapping wings

    NASA Astrophysics Data System (ADS)

    Hu, Zheng; Roll, Jesse; Cheng, Bo; Deng, Xinyan

    2010-11-01

    We investigated the aerodynamic performance of high frequency flapping wings using a 2.5 gram robotic insect mechanism developed in our lab. The mechanism flaps up to 65Hz with a pair of man-made wing mounted with 10cm wingtip-to-wingtip span. The mean aerodynamic lift force was measured by a lever platform, and the flow velocity and vorticity were measured using a stereo DPIV system in the frontal, parasagittal, and horizontal planes. Both near field (leading edge vortex) and far field flow (induced flow) were measured with instantaneous and phase-averaged results. Systematic experiments were performed on the man-made wings, cicada and hawk moth wings due to their similar size, frequency and Reynolds number. For insect wings, we used both dry and freshly-cut wings. The aerodynamic force increase with flapping frequency and the man-made wing generates more than 4 grams of lift at 35Hz with 3 volt input. Here we present the experimental results and the major differences in their aerodynamic performances.

  11. The cellular and molecular mechanisms of vertebrate lens development

    PubMed Central

    Cvekl, Aleš; Ashery-Padan, Ruth

    2014-01-01

    The ocular lens is a model system for understanding important aspects of embryonic development, such as cell specification and the spatiotemporally controlled formation of a three-dimensional structure. The lens, which is characterized by transparency, refraction and elasticity, is composed of a bulk mass of fiber cells attached to a sheet of lens epithelium. Although lens induction has been studied for over 100 years, recent findings have revealed a myriad of extracellular signaling pathways and gene regulatory networks, integrated and executed by the transcription factor Pax6, that are required for lens formation in vertebrates. This Review summarizes recent progress in the field, emphasizing the interplay between the diverse regulatory mechanisms employed to form lens progenitor and precursor cells and highlighting novel opportunities to fill gaps in our understanding of lens tissue morphogenesis. PMID:25406393

  12. 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.

  13. 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.

  14. 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.

  15. The Aerodynamic Plane Table

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1924-01-01

    This report gives the description and the use of a specially designed aerodynamic plane table. For the accurate and expeditious geometrical measurement of models in an aerodynamic laboratory, and for miscellaneous truing operations, there is frequent need for a specially equipped plan table. For example, one may have to measure truly to 0.001 inch the offsets of an airfoil at many parts of its surface. Or the offsets of a strut, airship hull, or other carefully formed figure may require exact calipering. Again, a complete airplane model may have to be adjusted for correct incidence at all parts of its surfaces or verified in those parts for conformance to specifications. Such work, if but occasional, may be done on a planing or milling machine; but if frequent, justifies the provision of a special table. For this reason it was found desirable in 1918 to make the table described in this report and to equip it with such gauges and measures as the work should require.

  16. 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.

  17. 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…

  18. 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)

  19. Veselago lens by photonic hyper-crystals

    SciTech Connect

    Huang, Zun Narimanov, Evgenii E.

    2014-07-21

    Based on the recent concept of the photonic hyper-crystal—an artificial optical medium that combines the properties of hyperbolic materials and photonic crystals, we present the imaging system functioning as a Veselago lens. This planar lens shows a nearly constant negative refractive index with substantially reduced image aberrations, and can find potential applications in photolithography and hot-spots detection of silicon-based integrated circuits.

  20. An Aerodynamic Analysis of a Spinning Missile with Dithering Canards

    NASA Technical Reports Server (NTRS)

    Meakin, Robert L.; Nygaard, Tor A.

    2003-01-01

    A generic spinning missile with dithering canards is used to demonstrate the utility of an overset structured grid approach for simulating the aerodynamics of rolling airframe missile systems. The approach is used to generate a modest aerodynamic database for the generic missile. The database is populated with solutions to the Euler and Navier-Stokes equations. It is used to evaluate grid resolution requirements for accurate prediction of instantaneous missile loads and the relative aerodynamic significance of angle-of-attack, canard pitching sequence, viscous effects, and roll-rate effects. A novel analytical method for inter- and extrapolation of database results is also given.

  1. Compendium of NASA Langley reports on hypersonic aerodynamics

    NASA Technical Reports Server (NTRS)

    Sabo, Frances E.; Cary, Aubrey M.; Lawson, Shirley W.

    1987-01-01

    Reference is made to papers published by the Langley Research Center in various areas of hypersonic aerodynamics for the period 1950 to 1986. The research work was performed either in-house by the Center staff or by other personnel supported entirely or in part by grants or contracts. Abstracts have been included with the references when available. The references are listed chronologically and are grouped under the following general headings: (1) Aerodynamic Measurements - Single Shapes; (2) Aerodynamic Measurements - Configurations; (3) Aero-Heating; (4) Configuration Studies; (5) Propulsion Integration Experiment; (6) Propulsion Integration - Study; (7) Analysis Methods; (8) Test Techniques; and (9) Airframe Active Cooling Systems.

  2. Unsteady aerodynamics of blade rows

    NASA Technical Reports Server (NTRS)

    Verdon, Joseph M.

    1989-01-01

    The requirements placed on an unsteady aerodynamic theory intended for turbomachinery aeroelastic or aeroacoustic applications are discussed along with a brief description of the various theoretical models that are available to address these requirements. The major emphasis is placed on the description of a linearized inviscid theory which fully accounts for the affects of a nonuniform mean or steady flow on unsteady aerodynamic response. Although this linearization was developed primarily for blade flutter prediction, more general equations are presented which account for unsteady excitations due to incident external aerodynamic disturbances as well as those due to prescribed blade motions. The motivation for this linearized unsteady aerodynamic theory is focused on, its physical and mathematical formulation is outlined and examples are presented to illustrate the status of numerical solution procedures and several effects of mean flow nonuniformity on unsteady aerodynamic response.

  3. Longitudinal and lateral-directional static aerodynamic characteristics of an unpowered escape system extraction rocket model with attached launch tubes

    NASA Technical Reports Server (NTRS)

    Huffman, J. K.; Fox, C. H., Jr.; Satterthwaite, R. E.

    1977-01-01

    An escape system extraction rocket proposed for use on the Rotor Systems Research Aircraft was tested at Mach numbers of 0.1 and 0.3 through an angle of attack range from -2 deg to 102 deg and an angle of sideslip range from 0 deg to 15 deg in the Langley 7- by 10-foot high speed tunnel. The data are presented without analysis.

  4. Contact lens hygiene compliance and lens case contamination: A review.

    PubMed

    Wu, Yvonne Tzu-Ying; Willcox, Mark; Zhu, Hua; Stapleton, Fiona

    2015-10-01

    A contaminated contact lens case can act as a reservoir for microorganisms that could potentially compromise contact lens wear and lead to sight threatening adverse events. The rate, level and profile of microbial contamination in lens cases, compliance and other risk factors associated with lens case contamination, and the challenges currently faced in this field are discussed. The rate of lens case contamination is commonly over 50%. Coagulase-negative Staphylococcus, Bacillus spp., Pseudomonas aeruginosa and Serratia marcescens are frequently recovered from lens cases. In addition, we provide suggestions regarding how to clean contact lens cases and improve lens wearers' compliance as well as future lens case design for reducing lens case contamination. This review highlights the challenges in reducing the level of microbial contamination which require an industry wide approach.

  5. Unitary lens semiconductor device

    DOEpatents

    Lear, K.L.

    1997-05-27

    A unitary lens semiconductor device and method are disclosed. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors. 9 figs.

  6. Unitary lens semiconductor device

    DOEpatents

    Lear, Kevin L.

    1997-01-01

    A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

  7. Intraocular lens fabrication

    DOEpatents

    Salazar, Mike A.; Foreman, Larry R.

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  8. Intraocular lens fabrication

    DOEpatents

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  9. Ultraviolet spectrograph lens

    SciTech Connect

    Brixner, B.; Winkler, M.A.

    1981-01-01

    A 700-mm f/4.7 spectrograph camera lens was designed for imaging spectral lines in the 200 to 400-nm region on a 120-mm flat image field. Lens elements of fused silica and crystalline calcium fluoride have so little secondary spectrum that raytracing calculations predict a monochromatic resolution limit of 30 lines/mm without refocusing in the 238- to 365-nm region. Light scattering at the polished calcium-fluoride surfaces is avoided by sandwiching the fluoride elements between fused silica and cementing with silicone fluid. The constructed lens makes good spectrograms.

  10. Ultraviolet-spectrograph lens

    SciTech Connect

    Brixner, B.; Winkler, M.A.

    1981-01-01

    A 700-mm f/4.7 spectrograph camera lens was designed for imaging spectral lines in the 200- to 400-nm region on a 120-mm flat image field. Lens elements of fused silica and crystal calcium fluoride give such good achromatization that raytracing calculations predict a resolution limit of 30 lines/mm without refocusing in the 238- to 365-nm region. Light scattering at the polished calcium-fluoride surfaces is avoided by sandwiching the fluoride elements between fused silica and cementing with silicone fluid. The constructed lens makes good spectrograms.

  11. 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.

  12. Reflections From a Fresnel Lens

    ERIC Educational Resources Information Center

    Keeports, David

    2005-01-01

    Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

  13. Optical switch based on electrowetting liquid lens

    NASA Astrophysics Data System (ADS)

    Li, Lei; Liu, Chao; Peng, Hua-Rong; Wang, Qiong-Hua

    2012-05-01

    In this paper, we propose an optical switch based on an electrowetting liquid lens. The device consists of an electrowetting liquid lens and a non-transparent cap with a pin hole. When the lens is actuated to be positive, the incident light can be converged on the pin hole and pass through the hole with less attenuation. When the lens is deformed to be negative, the incident light is diverged and most of light is blocked by the cap. Our results show that the system can provide high contrast ratio (˜800:1) and reasonable response time (˜88 ms). The proposed optical switch has potential application in light shutters, variable optical attenuators, and adaptive irises.

  14. 23-gauge vitrectomy for retained lens material.

    PubMed

    Bhandari, Ramanath; Ernst, Benjamin J; Stafeeva, Ksenia; Mandava, Naresh; Quiroz-Mercado, Hugo

    2012-07-01

    A technique for removal of retained lens material is described with a three-port 23-gauge vitrectomy system. Removal of the core vitreous is first performed, followed by removal of the cortical vitreous. All vitreous adhesions to the lens are cleared. The cut rate is then decreased to 1,500 cuts per minute, and vacuum increased to 600 mm Hg. The cortical lens material is cleared first, and then the nuclear material is taken with the same vitrectomy probe using the light pipe to assist in crushing the nuclear fragments. With this technique, even large dense nuclear and cortical retained lens material can be removed from the vitreous chamber without the need for a fragmatome. PMID:22692723

  15. Luneburg lens and optical matrix algebra research

    NASA Technical Reports Server (NTRS)

    Wood, V. E.; Busch, J. R.; Verber, C. M.; Caulfield, H. J.

    1984-01-01

    Planar, as opposed to channelized, integrated optical circuits (IOCs) were stressed as the basis for computational devices. Both fully-parallel and systolic architectures are considered and the tradeoffs between the two device types are discussed. The Kalman filter approach is a most important computational method for many NASA problems. This approach to deriving a best-fit estimate for the state vector describing a large system leads to matrix sizes which are beyond the predicted capacities of planar IOCs. This problem is overcome by matrix partitioning, and several architectures for accomplishing this are described. The Luneburg lens work has involved development of lens design techniques, design of mask arrangements for producing lenses of desired shape, investigation of optical and chemical properties of arsenic trisulfide films, deposition of lenses both by thermal evaporation and by RF sputtering, optical testing of these lenses, modification of lens properties through ultraviolet irradiation, and comparison of measured lens properties with those expected from ray trace analyses.

  16. A microcontroller-based system for automated and continuous sky glow measurements with the use of digital single-lens reflex cameras

    NASA Astrophysics Data System (ADS)

    Solano Lamphar, Hétor Antonio; Kundracik, Frantisek

    2014-02-01

    In recent years, the scientific community has shown an increased interest in sky glow research. This has revealed an increased need for automated technology that enables continuous evaluation of sky glow. As a result, a reliable low-cost platform has been developed and constructed for automating sky glow measurement. The core of the system is embedded software and hardware managed by a microcontroller with ARM architecture. A monolithic photodiode transimpedance amplifier is used to allow linear light measurement. Data from the diode are collected and used to arrange the exposure time of every image captured by the digital single-lens reflex camera. This proposal supports experimenters by providing a low-cost system to analyse sky glow variations overnight without a human interface.

  17. Layer Stack Design of High Density Read-Only-Memory Discs for Near-Field Systems using a Solid Immersion Lens

    NASA Astrophysics Data System (ADS)

    Kitano, Kazutoshi; Yamaguchi, Atsushi; Miura, Masahiro; Horikawa, Kunihiko; Tagiri, Takao; Muramatsu, Eiji; Taniguchi, Shoji; Yokogawa, Fumihiko

    2009-03-01

    For high numerical aperture (NA) near-field systems using a solid immersion lens, layer stack types of first-surface read-only-memory (ROM) discs have been investigated. Complicated interactions of high-NA incident and diffracted waves with surface waves occur in multilayer-stacked subwavelength structures on the discs. Therefore, vector diffraction simulation in consideration of these effects is indispensable for the optimization of the disc structures. We used rigorous coupled wave analysis to numerically calculate readout signals from the discs. On the basis of the simulation results, we actually fabricated high-density ROM media. Consequently, a significantly low jitter of 6.8% was obtained for 100 Gbyte ROM media with a designed structure in an NA 2.0 system.

  18. Contact Lens Risks

    MedlinePlus

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  19. Proposed electron halo detector system as one of the beam overlap diagnostic tools for the new RHIC electron lens

    SciTech Connect

    Thieberger, P.; Alessi, J.; Beebe, E.; Chasman, C.; Fischer, W.; Gassner, D.; Gu, X.; Gupta, R.; Hock, J.; Lambiase, R.; Montag, C.; Luo, Y.; Minty, M.; Okamura, M.; Pikin, A.; Tan, Y.; Tuozzolo, J.; Zhang, W.

    2011-03-28

    An electron lens for head-on beam-beam compensation planned for RHIC requires precise overlap of the electron and proton beams which both can have down to 0.3 mm rms transverse radial widths along the 2m long interaction region. Here we describe a new diagnostic tool that is being considered to aid in the tuning and verification of this overlap. Some of ultra relativistic protons (100 or 250 GeV) colliding with low energy electrons (2 to 10 keV) will transfer sufficient transverse momentum to cause the electrons to spiral around the magnetic guiding field in a way that will make them detectable outside of the main solenoid. Time-of-flight of the halo electron signals will provide position-sensitive information along the overlap region. Scattering cross sections are calculated and counting rate estimates are presented as function of electron energy and detector position.

  20. Aerodynamics of Small Vehicles

    NASA Astrophysics Data System (ADS)

    Mueller, Thomas J.

    In this review we describe the aerodynamic problems that must be addressed in order to design a successful small aerial vehicle. The effects of Reynolds number and aspect ratio (AR) on the design and performance of fixed-wing vehicles are described. The boundary-layer behavior on airfoils is especially important in the design of vehicles in this flight regime. The results of a number of experimental boundary-layer studies, including the influence of laminar separation bubbles, are discussed. Several examples of small unmanned aerial vehicles (UAVs) in this regime are described. Also, a brief survey of analytical models for oscillating and flapping-wing propulsion is presented. These range from the earliest examples where quasi-steady, attached flow is assumed, to those that account for the unsteady shed vortex wake as well as flow separation and aeroelastic behavior of a flapping wing. Experiments that complemented the analysis and led to the design of a successful ornithopter are also described.

  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. Vortex flow aerodynamics

    NASA Technical Reports Server (NTRS)

    Smith, J. H. B.; Campbell, J. F.; Young, A. D. (Editor)

    1992-01-01

    The principal emphasis of the meeting was to be on the understanding and prediction of separation-induced vortex flows and their effects on vehicle performance, stability, control, and structural design loads. This report shows that a substantial amount of the papers covering this area were received from a wide range of countries, together with an attendance that was even more diverse. In itself, this testifies to the current interest in the subject and to the appropriateness of the Panel's choice of topic and approach. An attempt is made to summarize each paper delivered, and to relate the contributions made in the papers and in the discussions to some of the important aspects of vortex flow aerodynamics. This reveals significant progress and important clarifications, but also brings out remaining weaknesses in predictive capability and gaps in understanding. Where possible, conclusions are drawn and areas of continuing concern are identified.

  3. Systems design study of the Pioneer Venus spacecraft. Volume 1. Technical analyses and tradeoffs, section 7 (part 3 of 4). [aerodynamic design problems for small probe reentry

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The aerodynamic design problems for the Pioneer Venus mission are discussed for a small probe shape that enters the atmosphere, and exhibits good stability for the subsonic portion of the flight. The problems discussed include: heat shield, structures and mechanisms, thermal control, decelerator, probe communication, data handling and command, and electric power.

  4. Design and fabrication of soft zoom lens

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Cheng; Chen, Chao-Chang A.; Huang, Kuo-Cheng

    2008-08-01

    With minimization of optical-electronics devices, conventional optical zoom lens component has been explored with liquid lens and soft polymer membranes. This paper introduces a novel zoom lens system with a soft polymer material, Polydimethylsiloxane (PDMS), its shape and curvature can be controlled by pneumatic pressure. Therefore, effective focal length (EFL) of soft zoom lens (SZL) system can be controlled and altered. According to desired opto-mechanical design, this ZL has been accessed to determine the optical specifications. After the pressure activated from 0 to 0.02MPa, the change of EFL of the SZL system can reach up to 18.77% (33.44mm to 39.717mm). Experimental results show that zoom effects of the developed SZL system are significantly affected by the shape, thickness and curing parameter of PDMS soft lens. The SZL system has been verified with the function of zoom ability. Further research works on the integration of the SZL system with imaging system for mobile devices or robot vision applications.

  5. Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 4: Advanced fan section aerodynamic analysis

    NASA Technical Reports Server (NTRS)

    Crook, Andrew J.; Delaney, Robert A.

    1992-01-01

    The purpose of this study is the development of a three-dimensional Euler/Navier-Stokes flow analysis for fan section/engine geometries containing multiple blade rows and multiple spanwise flow splitters. An existing procedure developed by Dr. J. J. Adamczyk and associates and the NASA Lewis Research Center was modified to accept multiple spanwise splitter geometries and simulate engine core conditions. The procedure was also modified to allow coarse parallelization of the solution algorithm. This document is a final report outlining the development and techniques used in the procedure. The numerical solution is based upon a finite volume technique with a four stage Runge-Kutta time marching procedure. Numerical dissipation is used to gain solution stability but is reduced in viscous dominated flow regions. Local time stepping and implicit residual smoothing are used to increase the rate of convergence. Multiple blade row solutions are based upon the average-passage system of equations. The numerical solutions are performed on an H-type grid system, with meshes being generated by the system (TIGG3D) developed earlier under this contract. The grid generation scheme meets the average-passage requirement of maintaining a common axisymmetric mesh for each blade row grid. The analysis was run on several geometry configurations ranging from one to five blade rows and from one to four radial flow splitters. Pure internal flow solutions were obtained as well as solutions with flow about the cowl/nacelle and various engine core flow conditions. The efficiency of the solution procedure was shown to be the same as the original analysis.

  6. Terahertz Artificial Dielectric Lens

    NASA Astrophysics Data System (ADS)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  7. Terahertz Artificial Dielectric Lens.

    PubMed

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M

    2016-01-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices. PMID:26973294

  8. Terahertz Artificial Dielectric Lens.

    PubMed

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M

    2016-03-14

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  9. Terahertz Artificial Dielectric Lens

    PubMed Central

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-01-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices. PMID:26973294

  10. Full-scale wind turbine rotor aerodynamics research

    SciTech Connect

    Simms, D A; Butterfield, C P

    1994-11-01

    The United States Department of Energy and the National Renewable Energy Laboratory (NREL) are conducting research to improve wind turbine technology at the NREL National Wind Technology Center (NWTC). 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 in stall-controlled HAWTs. Optimally twisted blades and innovative instrumentation and data acquisition systems will be used in these tests. Data can now be acquired and viewed interactively during turbine operations. This paper describes the NREL Unsteady Aerodynamics Experiment and highlights planned future research activities.

  11. Accomplishments at NASA Langley Research Center in rotorcraft aerodynamics technology

    NASA Technical Reports Server (NTRS)

    Wilson, John C.

    1988-01-01

    In recent years, the development of aerodynamic technology for rotorcraft has continued successfully at NASA LaRC. Though the NASA Langley Research Center is not the lead NASA center in this area, the activity was continued due to facilities and individual capabilities which are recognized as contributing to helicopter research needs of industry and government. Noteworthy accomplishments which contribute to advancing the state of rotorcraft technology in the areas of rotor design, airfoil research, rotor aerodynamics, and rotor/fuselage interaction aerodynamics are described. Rotor designs were defined for current helicopters and evaluated in wind tunnel testing. These designs have incorporated advanced airfoils defined analytically and also proven in wind tunnel tests. A laser velocimetry system has become a productive tool for experimental definition of rotor inflow/wake and is providing data for rotorcraft aerodynamic code validation.

  12. Role of Aquaporin 0 in lens biomechanics

    SciTech Connect

    Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G.; Menon, Anil G.; Mathias, Richard T.; Varadaraj, Kulandaiappan

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  13. Effects of reaction control system jet flow field interactions on the aerodynamic characteristics of a 0.010-scale space shuttle orbiter model in the Langley Research Center 31 inch CFHT (OA85)

    NASA Technical Reports Server (NTRS)

    Daileda, J. J.; Marroquin, J.

    1974-01-01

    An experimental investigation was conducted to obtain detailed effects on supersonic vehicle hypersonic aerodynamic and stability and control characteristics of reaction control system jet flow field interactions with the local vehicle flow field. A 0.010-scale model was used. Six-component force data and wing, elevon, and body flap surface pressure data were obtained through an angle-of-attack range of -10 to +35 degrees with 0 deg angle of sideslip. The test was conducted with yaw, pitch and roll jet simulation at a free-stream Mach number of 10.3 and reaction control system plume simulation of flight dynamic pressures of 5, 10 and 20 PSF.

  14. Turbine Aerodynamics Design Tool Development

    NASA Technical Reports Server (NTRS)

    Huber, Frank W.; Turner, James E. (Technical Monitor)

    2001-01-01

    This paper presents the Marshal Space Flight Center Fluids Workshop on Turbine Aerodynamic design tool development. The topics include: (1) Meanline Design/Off-design Analysis; and (2) Airfoil Contour Generation and Analysis. This paper is in viewgraph form.

  15. Atmospheric determination for Shuttle aerodynamic studies

    NASA Technical Reports Server (NTRS)

    Price, J. M.

    1983-01-01

    Evaluation of the aerodynamic performance of the Shuttle during atmospheric reentry requires a determination of the free-stream atmospheric properties along the entry path. This determination must be of the best possible accuracy in order to fully utilize the Shuttle as an aerodynamic flight research vehicle. To accomplish this, two Shuttle Orbiter experiments, the Shuttle Upper Atmosphere Mass Spectrometer (SUMS) and the Shuttle Entry Air Data System (SEADS), are being developed to provide onboard measurements. SUMS will measure freestream parameters in the high altitude (above 90 km), high Mach number (M above 20) regions where conventional static pressure measurements are not available. SEADS will provide research quality data below about 90 km. Since these two experiments were not installed for the Shuttle developmental flights, an alternate method was needed to determine the freestream atmospheric properties along the entry trajectory. The method which was developed is described with a discussion of the results from the first five Shuttle flights.

  16. A systematic review of strong gravitational lens modeling software

    NASA Astrophysics Data System (ADS)

    Lefor, Alan T.; Futamase, Toshifumi; Akhlaghi, Mohammad

    2013-07-01

    Despite expanding research activity in gravitational lens modeling, there is no particular software which is considered a standard. Much of the gravitational lens modeling software is written by individual investigators for their own use. Some gravitational lens modeling software is freely available for download but is widely variable with regard to ease of use and quality of documentation. This review of 13 software packages was undertaken to provide a single source of information. Gravitational lens models are classified as parametric models or non-parametric models, and can be further divided into research and educational software. Software used in research includes the GRAVLENS package (with both gravlens and lensmodel), Lenstool, LensPerfect, glafic, PixeLens, SimpLens, Lensview, and GRALE. In this review, GravLensHD, G-Lens, Gravitational Lensing, lens and MOWGLI are categorized as educational programs that are useful for demonstrating various aspects of lensing. Each of the 13 software packages is reviewed with regard to software features (installation, documentation, files provided, etc.) and lensing features (type of model, input data, output data, etc.) as well as a brief review of studies where they have been used. Recent studies have demonstrated the utility of strong gravitational lensing data for mass mapping, and suggest increased use of these techniques in the future. Coupled with the advent of greatly improved imaging, new approaches to modeling of strong gravitational lens systems are needed. This is the first systematic review of strong gravitational lens modeling software, providing investigators with a starting point for future software development to further advance gravitational lens modeling research. http://www.ephysics.org/mowgli/

  17. Aerodynamic Reconstruction Applied to Parachute Test Vehicle Flight Data Analysis

    NASA Technical Reports Server (NTRS)

    Cassady, Leonard D.; Ray, Eric S.; Truong, Tuan H.

    2013-01-01

    The aerodynamics, both static and dynamic, of a test vehicle are critical to determining the performance of the parachute cluster in a drop test and for conducting a successful test. The Capsule Parachute Assembly System (CPAS) project is conducting tests of NASA's Orion Multi-Purpose Crew Vehicle (MPCV) parachutes at the Army Yuma Proving Ground utilizing the Parachute Test Vehicle (PTV). The PTV shape is based on the MPCV, but the height has been reduced in order to fit within the C-17 aircraft for extraction. Therefore, the aerodynamics of the PTV are similar, but not the same as, the MPCV. A small series of wind tunnel tests and computational fluid dynamics cases were run to modify the MPCV aerodynamic database for the PTV, but aerodynamic reconstruction of the flights has proven an effective source for further improvements to the database. The acceleration and rotational rates measured during free flight, before parachute inflation but during deployment, were used to con rm vehicle static aerodynamics. A multibody simulation is utilized to reconstruct the parachute portions of the flight. Aerodynamic or parachute parameters are adjusted in the simulation until the prediction reasonably matches the flight trajectory. Knowledge of the static aerodynamics is critical in the CPAS project because the parachute riser load measurements are scaled based on forebody drag. PTV dynamic damping is critical because the vehicle has no reaction control system to maintain attitude - the vehicle dynamics must be understood and modeled correctly before flight. It will be shown here that aerodynamic reconstruction has successfully contributed to the CPAS project.

  18. Tunable optofluidic birefringent lens.

    PubMed

    Wee, D; Hwang, S H; Song, Y S; Youn, J R

    2016-05-01

    An optofluidic birefringent lens is demonstrated using hydrodynamic liquid-liquid (L(2)) interfaces in a microchannel. The L(2) lens comprises a nematic liquid crystal (NLC) phase and an optically isotropic phase for the main stream and the surrounding sub-stream, respectively. When the optofluidic device is subjected to a sufficiently strong electric field perpendicular to the flow direction, NLCs are allowed to orient along the external field rather than the flow direction overcoming fluidic viscous stress. The characteristics of the optofluidic birefringence lens are investigated by experimental and numerical analyses. The difference between the refractive indices of the main stream and the sub-stream changes according to the polarization direction of incident light, which determines the optical behaviour of the lens. The incidence of s-polarized light leads to a short focal point, while p-polarized light has a relatively long focal distance from the same L(2) interface. The curvatures and focal lengths of the lens are successfully evaluated by a hydrodynamic theory of NLCs and a simple ray-tracing model. PMID:27035877

  19. Lens dislocation has a possible relationship with laser iridotomy.

    PubMed

    Mutoh, Tetsuya; Barrette, Kevin F; Matsumoto, Yukihiro; Chikuda, Makoto

    2012-01-01

    We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation. PMID:23271880

  20. A passively tunable acoustic metamaterial lens for selective ultrasonic excitation

    SciTech Connect

    Zhu, H.; Semperlotti, F.

    2014-09-07

    In this paper, we present an approach to ultrasonic beam-forming and beam-steering in structures based on the concept of embedded acoustic metamaterial lenses. The lens design exploits the principle of acoustic drop-channel that enables the dynamic coupling of multiple ultrasonic waveguides at selected frequencies. In contrast with currently available technology, the embedded lens allows exploiting the host structure as a key component of the transducer system therefore enabling directional excitation by means of a single ultrasonic transducer. The design and the performance of the lens are numerically investigated by using Plane Wave Expansion and Finite Difference Time Domain techniques applied to bulk structures. Then, the design is experimentally validated on a thin aluminum plate waveguide where the lens is implemented by through-holes. The dynamic response of the embedded lens is estimated by reconstructing, via Laser Vibrometry, the velocity field induced by a single source located at the center of the lens.

  1. 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.

  2. 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.

  3. Aerodynamics of Laminar Flames

    NASA Astrophysics Data System (ADS)

    Law, Chung K.

    2000-11-01

    The presentation will review recent advances in the understanding of the structure, dynamics, and geometry of stretched, nonequidiffusive, laminar premixed flames, as exemplified by the unsteady propagation of wrinkled flames in nonuniform flow fields. It is first shown that by considering the effects of aerodynamic stretch on the flame structure, and by allowing for mixture nonequidiffusion, the flame responses, especially the flame propagation speed, can be quantitatively as well as qualitatively modified from the idealized planar limit. Subsequently, by treating the flame as a level surface propagating with the stretch-affected flame speed, problems of increasing complexity are presented to illustrate various features of flame propagation. The illustration first treats the flame as a structureless surface propagating into a constant-density combustible with a constant velocity * the laminar flame speed, and demonstrates the phenomena of cusp formation and volumetric burning rate augmentation through flame wrinkling. By using the stretch-affected flame speed, we then describe the phenomena of cusp broadening as well as tip opening of the Bunsen flame. Finally, by allowing for the density jump across the flame surface, a unified dispersion relation is derived for the intrinsic hydrodynamic, body-force, and nonequidiffusive modes of flame

  4. Introduction. Computational aerodynamics.

    PubMed

    Tucker, Paul G

    2007-10-15

    The wide range of uses of computational fluid dynamics (CFD) for aircraft design is discussed along with its role in dealing with the environmental impact of flight. Enabling technologies, such as grid generation and turbulence models, are also considered along with flow/turbulence control. The large eddy simulation, Reynolds-averaged Navier-Stokes and hybrid turbulence modelling approaches are contrasted. The CFD prediction of numerous jet configurations occurring in aerospace are discussed along with aeroelasticity for aeroengine and external aerodynamics, design optimization, unsteady flow modelling and aeroengine internal and external flows. It is concluded that there is a lack of detailed measurements (for both canonical and complex geometry flows) to provide validation and even, in some cases, basic understanding of flow physics. Not surprisingly, turbulence modelling is still the weak link along with, as ever, a pressing need for improved (in terms of robustness, speed and accuracy) solver technology, grid generation and geometry handling. Hence, CFD, as a truly predictive and creative design tool, seems a long way off. Meanwhile, extreme practitioner expertise is still required and the triad of computation, measurement and analytic solution must be judiciously used.

  5. Turbine Aerodynamic Design System Improvements

    NASA Technical Reports Server (NTRS)

    Huber, Frank W.; Griffin, Lisa W.; Simpson, Steven P.

    2003-01-01

    Presentation outline includes the following: 1. Volute manifold design and analysis methodology. 2. Meanline modification for compatibility with engine analysis code. Objective is to develop a manifold design methodology for turbines and pumps, and to enable rapid screening of candidate flow paths.

  6. Lens transmission measurement for an absolute radiation thermometer

    SciTech Connect

    Hao, X.; Yuan, Z.; Lu, X.

    2013-09-11

    The lens transmission for the National Institute of Metrology of China absolute radiation thermometer is measured by a hybrid method. The results of the lens transmission measurements are 99.002% and 86.792% for filter radiometers with center wavelengths 633 nm and 900 nm, respectively. These results, after correcting for diffraction factors and the size-of-source effect when the lens is incorporated within the radiometer, can be used for measurement of thermodynamic temperature. The expanded uncertainty of the lens transmission measurement system has been evaluated. It is 1.3×10{sup −3} at 633 nm and 900 nm, respectively.

  7. Optically controlled spherical liquid-crystal lens: theory and experiment

    SciTech Connect

    Gural'nik, I R; Samagin, S A

    2003-05-31

    A liquid-crystal lens with the focal distance depending on the transmitted light intensity is proposed and studied. A theoretical model is developed which adequately describes the wave-front formation by the lens. The results of visualisation of the wave-front control in a setup with crossed Polaroids and the intensity distributions, which characterise the focusing properties of the lens, are presented. To illustrate the application of the lens, an adaptive-optics system is built for stabilisation of radiation power on a 1-mm diaphragm, which reduces the power fluctuations by a factor of 30. (control of laser radiation parameters)

  8. Assessing the elasticity change of cataract lens with OCE

    NASA Astrophysics Data System (ADS)

    Wu, Chen; Liu, Chih-Hao; Raghunathan, Raksha; Singh, Manmohan; Li, Jiasong; Han, Zhaolong; Larin, Kirill V.

    2016-03-01

    Cataract is one of the most common degenerative diseases that causes blindness. Careful quantification of lens biomechanical properties can greatly assist in early detection of the disease as well as personalization of treatment procedures. In this study, we utilize a phase-sensitive optical coherence elastography (OCE) system to assess the effects of the cold cataract on the biomechanical properties of porcine crystalline lens in vitro. Relaxation rates of air puff induced elastic waves were measured on the same crystalline lens with and without cold cataract. Results demonstrate that the relaxation rate and, thus, associated elasticity of the porcine lens, increased due to the presence of cold cataract.

  9. Improved Aerodynamic Analysis for Hybrid Wing Body Conceptual Design Optimization

    NASA Technical Reports Server (NTRS)

    Gern, Frank H.

    2012-01-01

    This paper provides an overview of ongoing efforts to develop, evaluate, and validate different tools for improved aerodynamic modeling and systems analysis of Hybrid Wing Body (HWB) aircraft configurations. Results are being presented for the evaluation of different aerodynamic tools including panel methods, enhanced panel methods with viscous drag prediction, and computational fluid dynamics. Emphasis is placed on proper prediction of aerodynamic loads for structural sizing as well as viscous drag prediction to develop drag polars for HWB conceptual design optimization. Data from transonic wind tunnel tests at the Arnold Engineering Development Center s 16-Foot Transonic Tunnel was used as a reference data set in order to evaluate the accuracy of the aerodynamic tools. Triangularized surface data and Vehicle Sketch Pad (VSP) models of an X-48B 2% scale wind tunnel model were used to generate input and model files for the different analysis tools. In support of ongoing HWB scaling studies within the NASA Environmentally Responsible Aviation (ERA) program, an improved finite element based structural analysis and weight estimation tool for HWB center bodies is currently under development. Aerodynamic results from these analyses are used to provide additional aerodynamic validation data.

  10. Future Challenges and Opportunities in Aerodynamics

    NASA Technical Reports Server (NTRS)

    Kumar, Ajay; Hefner, Jerry N.

    2000-01-01

    Investments in aeronautics research and technology have declined substantially over the last decade, in part due to the perception that technologies required in aircraft design are fairly mature and readily available. This perception is being driven by the fact that aircraft configurations, particularly the transport aircraft, have evolved only incrementally, over last several decades. If however, one considers that the growth in air travel is expected to triple in the next 20 years, it becomes quickly obvious that the evolutionary development of technologies is not going to meet the increased demands for safety, environmental compatibility, capacity, and economic viability. Instead, breakthrough technologies will he required both in traditional disciplines of aerodynamics, propulsion, structures, materials, controls, and avionics as well as in the multidisciplinary integration of these technologies into the design of future aerospace vehicles concepts. The paper discusses challenges and opportunities in the field of aerodynamics over the next decade. Future technology advancements in aerodynamics will hinge on our ability, to understand, model, and control complex, three-dimensional, unsteady viscous flow across the speed range. This understanding is critical for developing innovative flow and noise control technologies and advanced design tools that will revolutionize future aerospace vehicle systems and concepts. Specifically, the paper focuses on advanced vehicle concepts, flow and noise control technologies, and advanced design and analysis tools.

  11. Asymmetric Uncertainty Expression for High Gradient Aerodynamics

    NASA Technical Reports Server (NTRS)

    Pinier, Jeremy T

    2012-01-01

    When the physics of the flow around an aircraft changes very abruptly either in time or space (e.g., flow separation/reattachment, boundary layer transition, unsteadiness, shocks, etc), the measurements that are performed in a simulated environment like a wind tunnel test or a computational simulation will most likely incorrectly predict the exact location of where (or when) the change in physics happens. There are many reasons for this, includ- ing the error introduced by simulating a real system at a smaller scale and at non-ideal conditions, or the error due to turbulence models in a computational simulation. The un- certainty analysis principles that have been developed and are being implemented today do not fully account for uncertainty in the knowledge of the location of abrupt physics changes or sharp gradients, leading to a potentially underestimated uncertainty in those areas. To address this problem, a new asymmetric aerodynamic uncertainty expression containing an extra term to account for a phase-uncertainty, the magnitude of which is emphasized in the high-gradient aerodynamic regions is proposed in this paper. Additionally, based on previous work, a method for dispersing aerodynamic data within asymmetric uncer- tainty bounds in a more realistic way has been developed for use within Monte Carlo-type analyses.

  12. Overview of the multilayer-Fresnel zone plate and the kinoform lens development at MPI for intelligent systems

    NASA Astrophysics Data System (ADS)

    Tunca Sanli, Umut; Keskinbora, Kahraman; Grévent, Corinne; Schütz, Gisela

    2015-05-01

    The ultimate goal of our research is to develop novel fabrication methods for high efficiency and high resolution X-ray optics. To this end, we have been pursuing the fabrication of several innovative diffractive/refractive optics designs. One such optic is the multilayer type Fresnel zone plate (ML-FZP). Our fabrication process relies on the atomic layer deposition (ALD) of two materials on a smooth glass fiber followed by a focused ion beam (FIB) based slicing and polishing. The ALD process allows much smaller outermost zone widths than the standard electron beam lithography based FZPs, meaning FZPs with potentially higher resolutions. Moreover, by depositing the multilayer on a cm long glass-fiber FZPs with very high optical thicknesses can be fabricated that can efficiently focus harder X-rays as well. A 21 nm half-pitch resolution was achieved using the ML-FZPs. Another optic we have been working on is the kinoform lens, which is a refractive/diffractive optic with a 100 % theoretical focusing efficiency. Their fabrication is usually realized by using approximate models which limit their success. Recently the fabrication of real kinoform lenses has been successfully realized in our lab via gray-scale direct-write ion beam lithography without any approximations. The lenses have been tested in the soft X-ray range achieving up to ~90 % of the calculated efficiency which indicates outstanding replication of the designed profile. Here we give an overview of our research and discuss the future challenges and opportunities for these optics.

  13. Clinical research into hyperthermia treatment of cancer using a 430 MHz microwave heating system with a lens applicator.

    PubMed

    Matsuda, T; Kikuchi, M; Tanaka, Y; Hiraoka, M; Nishimura, Y; Akuta, K; Takahashi, M; Abe, M; Fuwa, N; Morita, K

    1991-01-01

    Tokyo Metropolitan Komagome Hospital, Kyoto University Hospital, and Aichi Cancer Center used a lens applicator microwave equipment, the HTS-100, to treat 90 patients with a total of 96 tumours. The results were analysed, and the following conclusions reached. Three clinical cases have been presented to illustrate the features of the HTS-100. (1) The results of 383 heating sessions using the HTS-100 were analysed. Even tumours larger and deeper than 5 cm could be heated above 42 degrees C. The heating area is much wider than that of the other 2450, 915, 430 MHz microwave heating equipments. (2) Hyperthermia treatment using the HTS-100 was combined with radiotherapy. The percentage effectiveness in terms of CR+PRa was 66.3% for the 89 cases which could be evaluated. Even for tumours larger than 5 cm, and deeper than 4 cm, local control was achieved in 60.7%. Thus, the indications for microwave heating have been significantly expanded. (3) Combination of microwave heating and RF heating is a new protocol which also expands the indications for hyperthermia therapy. (4) The percentage of patients experiencing the side-effects of pain, a sensation of heat, and burns was 15.6%, 6.3%, and 3.6%, respectively. Most of these side-effects were mild and temporary. The percentage of patients experiencing pain was higher than in conventional microwave heating, probably because the area of heating was wider. (5) In the future, the HTS-100 can be expected to play an important role in clinical cancer hyperthermia.

  14. Microoptical compound lens

    DOEpatents

    Sweatt, William C.; Gill, David D.

    2007-10-23

    An apposition microoptical compound lens comprises a plurality of lenslets arrayed around a segment of a hollow, three-dimensional optical shell. The lenslets collect light from an object and focus the light rays onto the concentric, curved front surface of a coherent fiber bundle. The fiber bundle transports the light rays to a planar detector, forming a plurality of sub-images that can be reconstructed as a full image. The microoptical compound lens can have a small size (millimeters), wide field of view (up to 180.degree.), and adequate resolution for object recognition and tracking.

  15. Low scatter lens design/development

    NASA Technical Reports Server (NTRS)

    Gallipeau, R. B.; Quesada, A.

    1974-01-01

    The criteria for the optimum design of optical systems are discussed along with the selection of appropriate materials. The construction details of low scatter lens systems are tabulated. Scattering analysis; total energy diffracted; and computation of delta for a scratch, bubble, and microscopic irregularities are also discussed.

  16. RHIC electron lens test bench diagnostics

    SciTech Connect

    Gassner, D.; Beebe, E.; Fischer, W.; Gu, X.; Hamdi, K.; Hock, J.; Liu, C.; Miller, T.; Pikin, A.; Thieberger, P.

    2011-05-16

    An Electron Lens (E-Lens) system will be installed in RHIC to increase luminosity by counteracting the head-on beam-beam interaction. The proton beam collisions at the RHIC experimental locations will introduce a tune spread due to a difference of tune shifts between small and large amplitude particles. A low energy electron beam will be used to improve luminosity and lifetime of the colliding beams by reducing the betatron tune shift and spread. In preparation for the Electron Lens installation next year, a test bench facility will be used to gain experience with many sub-systems. This paper will discuss the diagnostics related to measuring the electron beam parameters.

  17. A Tribute to Len Barton

    ERIC Educational Resources Information Center

    Tomlinson, Sally

    2010-01-01

    This article constitutes a short personal tribute to Len Barton in honour of his work and our collegial relationship going back over 30 years. It covers how Len saw his intellectual project of providing critical sociological and political perspectives on special education, disability and inclusion, and his own radical political perspectives. Len's…

  18. 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.

  19. Aerodynamic Flight-Test Results for the Adaptive Compliant Trailing Edge

    NASA Technical Reports Server (NTRS)

    Cumming, Stephen B.; Smith, Mark S.; Ali, Aliyah N.; Bui, Trong T.; Ellsworth, Joel C.; Garcia, Christian A.

    2016-01-01

    The aerodynamic effects of compliant flaps installed onto a modified Gulfstream III airplane were investigated. Analyses were performed prior to flight to predict the aerodynamic effects of the flap installation. Flight tests were conducted to gather both structural and aerodynamic data. The airplane was instrumented to collect vehicle aerodynamic data and wing pressure data. A leading-edge stagnation detection system was also installed. The data from these flights were analyzed and compared with predictions. The predictive tools compared well with flight data for small flap deflections, but differences between predictions and flight estimates were greater at larger deflections. This paper describes the methods used to examine the aerodynamics data from the flight tests and provides a discussion of the flight-test results in the areas of vehicle aerodynamics, wing sectional pressure coefficient profiles, and air data.

  20. 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.