Science.gov

Sample records for high speed phenomena

  1. Thermomechanical phenomena in high speed rubbing

    NASA Technical Reports Server (NTRS)

    Kennedy, F. E.

    1980-01-01

    An analytical approach is presented for the modeling of the thermomechanical interactions which occur in high speed sliding situations. These sliding contact problems which are characterized by active and interrelated thermal and mechanical phenomena could be called 'rub energetics' problems. Analytical models were developed to simulate two different rub situations: high energy braking of disk brakes and high speed rubs of gas path seals in turbine engines. The models proved to be particularly useful in predicting the severe temperatures and deformations near hot contact patches on the rubbing surfaces. The size of the hot patches is generally determined by normal load and the properties of the contacting materials. Temperatures at the contact patches can approach the melting point of the materials, especially at high sliding velocities. These high temperatures can lead to large amounts of near-surface deformation and high wear rates. Decreased contact temperatures can result from using materials with increased thermal conductivity and increased heat capacity or choosing mechanical properties (decreased stiffness, yield stress or coefficient of thermal expansion) which give larger hot spot size.

  2. High-speed imaging system for observation of discharge phenomena

    NASA Astrophysics Data System (ADS)

    Tanabe, R.; Kusano, H.; Ito, Y.

    2008-11-01

    A thin metal electrode tip instantly changes its shape into a sphere or a needlelike shape in a single electrical discharge of high current. These changes occur within several hundred microseconds. To observe these high-speed phenomena in a single discharge, an imaging system using a high-speed video camera and a high repetition rate pulse laser was constructed. A nanosecond laser, the wavelength of which was 532 nm, was used as the illuminating source of a newly developed high-speed video camera, HPV-1. The time resolution of our system was determined by the laser pulse width and was about 80 nanoseconds. The system can take one hundred pictures at 16- or 64-microsecond intervals in a single discharge event. A band-pass filter at 532 nm was placed in front of the camera to block the emission of the discharge arc at other wavelengths. Therefore, clear images of the electrode were recorded even during the discharge. If the laser was not used, only images of plasma during discharge and thermal radiation from the electrode after discharge were observed. These results demonstrate that the combination of a high repetition rate and a short pulse laser with a high speed video camera provides a unique and powerful method for high speed imaging.

  3. High-speed photography of microscale blast wave phenomena

    NASA Astrophysics Data System (ADS)

    Dewey, John M.; Kleine, Harald

    2005-03-01

    High-speed photography has been a primary tool for the study of blast wave phenomena, dating from the work of Toepler, even before the invention of the camera! High-speed photography was used extensively for the study of blast waves produced by nuclear explosions for which, because of the large scale, cameras running at a few hundred frames per second were adequate to obtain sharp images of the supersonic shock fronts. For the study of the blast waves produced by smaller explosive sources, ever-increasing framing rates were required. As a rough guide, for every three orders of magnitude decrease in charge size a ten-fold increase of framing rate was needed. This severely limited the use of photography for the study of blast waves from laboratory-scale charges. There are many techniques for taking single photographs of explosive phenomena, but the strongly time-dependent development of a blast wave, requires the ability to record a high-speed sequence of photographs of a single event. At ICHSPP25, Kondo et al of Shimadzu Corporation demonstrated a 1 M fps video camera that provides a sequence of up to 100 high-resolution frames. This was subsequently used at the Shock Wave Research Center of Tohoku University to record the blast waves generated by an extensive series of silver azide charges ranging in size from 10 to 0.5mg. The resulting images were measured to provide radius-time histories of the primary and secondary shocks. These were analyzed with techniques similar to those used for the study of explosions from charges with masses ranging from 500 kg to 5 kt. The analyses showed the cube-root scaling laws to be valid for the very small charges, and provided a detailed record of the peak hydrostatic pressure as a function of radius for a unit charge of silver azide, over a wide range of scaled distances. The pressure-radius variation was compared to that from a unit charge of TNT and this permitted a detailed determination of the TNT equivalence of silver azide

  4. Wind Tunnel Studies in Aerodynamic Phenomena at High Speed

    NASA Technical Reports Server (NTRS)

    Caldwell, F W; Fales, E N

    1921-01-01

    A great amount of research and experimental work has been done and fair success obtained in an effort to place airplane and propeller design upon an empirical basis. However, one can not fail to be impressed by the apparent lack of data available toward establishing flow phenomena upon a rational basis, such that they may be interpreted in terms of the laws of physics. With this end in view it was the object of the authors to design a wind tunnel differing from the usual type especially in regard to large power and speed of flow. This report describes the wind tunnel at Mccook Field and gives the results of experiments conducted in testing the efficiency of the wind tunnel.

  5. Visualization of high speed phenomena using high-speed infrared camera

    NASA Astrophysics Data System (ADS)

    Yaoita, T.; Marcotte, F.

    2017-02-01

    The standard infrared camera has taken certain integration time with the photography per once, it was unsuitable for high-speed photography. By the infrared camera which can buffer photography data efficiently continually, high-speed photography of 2,000fps is enabled in 320X240 pixels and 11,000fps in128X100 pixels by windowing mode. The heat generation of specimen phenomenon is used for the monitoring of the start point of the destruction and the thermometry of combustion gases.

  6. Nonreproducible phenomena in thermal ink jets with real high-speed cine photomicrography

    NASA Astrophysics Data System (ADS)

    Rembe, Christian; aus der Wiesche, Stefan; Beuten, Michael; Hofer, Eberhard P.

    1998-09-01

    In the ink jet printer industry the stroboscopic visualization method is a standard tool for the characterization of printheads. However, this method fails for thermal ink jets in case of the existence of satellite droplets which are very critical considering print quality. This is also true for the bubble formation inside the ink chamber of the printhead. Detailed studies have shown that the phenomenon of satellite droplets is a nonreproducible dynamic process. Real high speed cine photomicrography forms the basis of a new test setup which allows the visualization of such highly dynamic nonreproducible phenomena. This new setup has been used to study the ejection, the free flight, and the impact of droplets of an ink jet on print media under real printing conditions.

  7. Ultra-high-speed studies of shock phenomena in a miniaturized system: A preliminary evaluation

    SciTech Connect

    Trott, W.M.; Erickson, K.L.

    1997-09-01

    A laboratory-scale experimental test system for small-scale of shock phenomena has been assembled. This system uses a variety of miniature test platforms in which shock loading is provided by laser-driven flyer impact. Acceptor materials include thin-film explosives and high-density metal foils. Optical access is provided for high-speed optical diagnostics such as optically recording velocity interferometry and single-pulse Raman spectroscopy. The experimental assembly for Raman studies features a common laser source for both flyer generation and excitation of Raman scattering (to achieve high timing precision) and a detection scheme that uses the coupling fiber for the excitation source to collect with high efficiency backscattered Raman light. Preliminary system evaluation experiments indicate that detailed particle velocity studies of the dynamic material properties of high-density metals under short-pulse, high-strain-rate loading can be performed in a miniaturized test configuration. Single-pulse Raman studies on shock compressed thin film explosives also appear feasible if the thickness and grain structure of these films can be tailored to enhance the Raman scattering signal sufficiently. Possible improvements in the experimental design and a number of likely applications of these techniques are also discussed.

  8. Investigating high speed phenomena in laser plasma interactions using dilation x-ray imager (invited)

    SciTech Connect

    Nagel, S. R. Bell, P. M.; Bradley, D. K.; Ayers, M. J.; Piston, K.; Felker, B.; Hilsabeck, T. J.; Kilkenny, J. D.; Chung, T.; Sammuli, B.; Hares, J. D.; Dymoke-Bradshaw, A. K. L.

    2014-11-15

    The DIlation X-ray Imager (DIXI) is a new, high-speed x-ray framing camera at the National Ignition Facility (NIF) sensitive to x-rays in the range of ≈2–17 keV. DIXI uses the pulse-dilation technique to achieve a temporal resolution of less than 10 ps, a ≈10× improvement over conventional framing cameras currently employed on the NIF (≈100 ps resolution), and otherwise only attainable with 1D streaked imaging. The pulse-dilation technique utilizes a voltage ramp to impart a velocity gradient on the signal-bearing electrons. The temporal response, spatial resolution, and x-ray sensitivity of DIXI are characterized with a short x-ray impulse generated using the COMET laser facility at Lawrence Livermore National Laboratory. At the NIF a pinhole array at 10 cm from target chamber center (tcc) projects images onto the photocathode situated outside the NIF chamber wall with a magnification of ≈64×. DIXI will provide important capabilities for warm-dense-matter physics, high-energy-density science, and inertial confinement fusion, adding important capabilities to temporally resolve hot-spot formation, x-ray emission, fuel motion, and mix levels in the hot-spot at neutron yields of up to 10{sup 17}. We present characterization data as well as first results on electron-transport phenomena in buried-layer foil experiments.

  9. A high sensitivity 20Mfps CMOS image sensor with readout speed of 1Tpixel/sec for visualization of ultra-high speed phenomena

    NASA Astrophysics Data System (ADS)

    Kuroda, R.; Sugawa, S.

    2017-02-01

    Ultra-high speed (UHS) CMOS image sensors with on-chop analog memories placed on the periphery of pixel array for the visualization of UHS phenomena are overviewed in this paper. The developed UHS CMOS image sensors consist of 400H×256V pixels and 128 memories/pixel, and the readout speed of 1Tpixel/sec is obtained, leading to 10 Mfps full resolution video capturing with consecutive 128 frames, and 20 Mfps half resolution video capturing with consecutive 256 frames. The first development model has been employed in the high speed video camera and put in practical use in 2012. By the development of dedicated process technologies, photosensitivity improvement and power consumption reduction were simultaneously achieved, and the performance improved version has been utilized in the commercialized high-speed video camera since 2015 that offers 10 Mfps with ISO16,000 photosensitivity. Due to the improved photosensitivity, clear images can be captured and analyzed even under low light condition, such as under a microscope as well as capturing of UHS light emission phenomena.

  10. Digital holographic high-speed 3D imaging for the vibrometry of fast-occurring phenomena.

    PubMed

    Kakue, Takashi; Endo, Yutaka; Nishitsuji, Takashi; Shimobaba, Tomoyoshi; Masuda, Nobuyuki; Ito, Tomoyoshi

    2017-09-05

    Digital holography allows production of high-speed three-dimensional images at rates over 100,000 frames per second; however, simultaneously obtaining suitable performance and levels of accuracy using digital holography is difficult. This problem prevents high-speed three-dimensional imaging from being used for vibrometry. In this paper, we propose and test a digital holography method that can produce vibration measurements. The method is based on single-shot phase-shifting interferometry. Herein, we imaged the surface of a loudspeaker diaphragm and measured its displacement due to the vibrations produced by a frequency sweep signal. We then analyzed the frequency of the experimental data and confirmed that the frequency spectra inferred from the reconstructed images agreed well with the spectra produced by the sound recorded by a microphone. This method can be used for measuring vibrations with three-dimensional imaging for loudspeakers, microelectromechanical systems, surface acoustic wave filters, and biological tissues and organs.

  11. Phenomena associated with complex (dusty) plasmas in the ionosphere during high-speed meteor showers

    SciTech Connect

    Kopnin, S. I.; Popel, S. I.; Yu, M. Y.

    2009-06-15

    Formation of dusty plasmas in the Earth's ionosphere at 80-120 km altitudes during high-speed meteor showers and its detectable manifestations are discussed. Emphasis is given to ground-based observations such as detection of low-frequency (<50 Hz) ionospheric radio noise, ground-based observations of infrasonic waves, and amplification of the intensity of green radiation at 557.7 nm from a layer at the 110-120 km altitude in the lower ionosphere. The physical processes responsible for these manifestations are considered.

  12. Design Considerations for Remote High-Speed Pressure Measurements of Dynamic Combustion Phenomena

    SciTech Connect

    Straub, D.L.; Ferguson, D.H.; Rohrssen, Robert; Perez, Eduardo

    2007-01-01

    As gas turbine combustion systems evolve to achieve ultra-low emission targets, monitoring and controlling dynamic combustion processes becomes increasingly important. These dynamic processes may include flame extinction, combustion-driven instabilities, or other dynamic combustion phenomena. Pressure sensors can be incorporated into the combustor liner design, but this approach is complicated by the harsh operating environment. One practical solution involves locating the sensor in a more remote location, such as outside the pressure casing. The sensor can be connected to the measurement point by small diameter tubing. Although this is a practical approach, the dynamics of the tubing can introduce significant errors into the pressure measurement. This paper addresses measurement errors associated with semi-infinite coil remote sensing setups and proposes an approach to improve the accuracy of these types of measurements.

  13. Pressure measurements and high speed visualizations of the cavitation phenomena at deep part load condition in a Francis turbine

    NASA Astrophysics Data System (ADS)

    Yamamoto, K.; Müller, A.; Favrel, A.; Landry, C.; Avellan, F.

    2014-03-01

    In a hydraulic power plant, it is essential to provide a reliable, sustainable and flexible energy supply. In recent years, in order to cover the variations of the renewable electricity production, hydraulic power plants are demanded to operate with more extended operating range. Under these off-design conditions, a hydraulic turbine is subject to cavitating swirl flow at the runner outlet. It is well-known that the helically/symmetrically shaped cavitation develops at the runner outlet in part load/full load condition, and it gives severe damage to the hydraulic systems under certain conditions. Although there have been many studies about partial and full load conditions, contributions reporting the deep part load condition are limited, and the cavitation behaviour at this condition is not yet understood. This study aims to unveil the cavitation phenomena at deep part load condition by high speed visualizations focusing on the draft tube cone as well as the runner blade channel, and pressure fluctuations associated with the phenomena were also investigated.

  14. Local Limit Phenomena, Flow Compression, and Fuel Cracking Effects in High-Speed Turbulent Flames

    DTIC Science & Technology

    2015-06-01

    components are frequently employed to develop chemical kinetic models to capture the major properties of the real fuels, e.g. the distillation curves...pure n-dodecane can be a sufficiently accurate jet fuel surrogate for high-T ignition and extinction, such that a simple chemical kinetic mechanism...6. A dynamic adaptive hybrid method for stiff chemistry integration (AHI) Detailed chemical kinetic models are expensive to be accommodated in CFD

  15. High-Speed Visualization of Evaporation Phenomena from Tungsten Based Electrode in Multi-Phase AC Arc

    NASA Astrophysics Data System (ADS)

    Tanaka, Manabu; Hashizume, Taro; Imatsuji, Tomoyuki; Nawata, Yushi; Watanabe, Takayuki

    2015-09-01

    A multi-phase AC arc has been developed for applications in various fields of engineering because it possesses unique advantages such as high energy efficiency. However, understanding of fundamental phenomena in the multi-phase AC arc is still insufficient for practical use. Purpose of this study is to investigate electrode erosion mechanism by high-speed visualization of the electrode metal vapor in the arc. Results indicated that the electrode mainly evaporated at anodic period, leading to the arc constriction. Moreover, evaporation of W electrode with 2wt% La2O3 at the anodic period was much higher than that with 2wt% ThO2. This can be explained by different properties of these oxide additives. Evaporation of the oxide additive resulted in the arc constriction, which accelerated the evaporation of W electrode. Therefore, addition of La2O3 with lower melting and boiling point than ThO2 lead to stronger arc constriction, resulting in severer evaporation of W electrode.

  16. Acceleration phenomena of high-speed wind observed at 0.1-0.3 AU with interplanetary scintillation

    NASA Technical Reports Server (NTRS)

    Kojima, M.; Misawa, H.; Watanabe, H.; Yamauchi, Y.

    1995-01-01

    The radial distance dependence of solar wind speeds, which were measured by interplanetary scintillation method, has been studied especially for a high-speed solar wind, and large increase of the IPS speeds (300 km/s) was observed at the distance range of 0.1 - 0.3 AU. When the streams are mapped back onto the source surface, they distribute in polar coronal holes or their boundaries. Since the IPS measurement can be biased by several effects such as of line-of-sight integration, strong scattering and random velocities, we examined these biasing effects and have found difficulty to explain the large IPS speed increase with the biasing effects.

  17. Examining the temporal evolution of hypervelocity impact phenomena via high-speed imaging and ultraviolet-visible emission spectroscopy

    SciTech Connect

    Tandy, J. D.; Mihaly, J. M.; Adams, M. A.; Rosakis, A. J.

    2014-07-21

    The temporal evolution of a previously observed hypervelocity impact-induced vapor cloud [Mihaly et al., Int. J. Impact Eng. 62, 13 (2013)] was measured by simultaneously recording several full-field, near-IR images of the resulting emission using an OMA-V high-speed camera. A two-stage light-gas gun was used to accelerate 5 mg Nylon 6/6 right-cylinders to speeds between 5 km/s and 7 km/s to impact 1.5 mm thick 6061-T6 aluminum target plates. Complementary laser-side-lighting [Mihaly et al., Int. J. Impact Eng. 62, 13 (2013); Proc. Eng. 58, 363 (2013)] and front-of-target (without laser illumination) images were also captured using a Cordin ultra-high-speed camera. The rapid expansion of the vapor cloud was observed to contain a bright, emitting exterior, and a darker, optically thick interior. The shape of this phenomenon was also observed to vary considerably between experiments due to extremely high-rate (>250 000 rpm) of tumbling of the cylindrical projectiles. Additionally, UV-vis emission spectra were simultaneously recorded to investigate the temporal evolution of the atomic and molecular composition of the up-range, impact-induced vapor plume. A PI-MAX3 high-speed camera coupled to an Acton spectrograph was utilized to capture the UV-vis spectra, which shows an overall peak in emission intensity between approximately 6–10 μs after impact trigger, corresponding to an increased quantity of emitting vapor/plasma passing through the spectrometer slit during this time period. The relative intensity of the numerous spectral bands was also observed to vary according to the exposure delay of the camera, indicating that the different atomic/molecular species exhibit a varied temporal evolution during the vapor cloud expansion. Higher resolution spectra yielded additional emission lines/bands that provide further evidence of interaction between fragmented projectile material and the 1 mmHg atmosphere inside the target chamber. A comparison of the

  18. Examining the temporal evolution of hypervelocity impact phenomena via high-speed imaging and ultraviolet-visible emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Tandy, J. D.; Mihaly, J. M.; Adams, M. A.; Rosakis, A. J.

    2014-07-01

    The temporal evolution of a previously observed hypervelocity impact-induced vapor cloud [Mihaly et al., Int. J. Impact Eng. 62, 13 (2013)] was measured by simultaneously recording several full-field, near-IR images of the resulting emission using an OMA-V high-speed camera. A two-stage light-gas gun was used to accelerate 5 mg Nylon 6/6 right-cylinders to speeds between 5 km/s and 7 km/s to impact 1.5 mm thick 6061-T6 aluminum target plates. Complementary laser-side-lighting [Mihaly et al., Int. J. Impact Eng. 62, 13 (2013); Proc. Eng. 58, 363 (2013)] and front-of-target (without laser illumination) images were also captured using a Cordin ultra-high-speed camera. The rapid expansion of the vapor cloud was observed to contain a bright, emitting exterior, and a darker, optically thick interior. The shape of this phenomenon was also observed to vary considerably between experiments due to extremely high-rate (>250 000 rpm) of tumbling of the cylindrical projectiles. Additionally, UV-vis emission spectra were simultaneously recorded to investigate the temporal evolution of the atomic and molecular composition of the up-range, impact-induced vapor plume. A PI-MAX3 high-speed camera coupled to an Acton spectrograph was utilized to capture the UV-vis spectra, which shows an overall peak in emission intensity between approximately 6-10 μs after impact trigger, corresponding to an increased quantity of emitting vapor/plasma passing through the spectrometer slit during this time period. The relative intensity of the numerous spectral bands was also observed to vary according to the exposure delay of the camera, indicating that the different atomic/molecular species exhibit a varied temporal evolution during the vapor cloud expansion. Higher resolution spectra yielded additional emission lines/bands that provide further evidence of interaction between fragmented projectile material and the 1 mmHg atmosphere inside the target chamber. A comparison of the data to down

  19. Visualization of explosion phenomena using a high-speed video camera with an uncoupled objective lens by fiber-optic

    NASA Astrophysics Data System (ADS)

    Tokuoka, Nobuyuki; Miyoshi, Hitoshi; Kusano, Hideaki; Hata, Hidehiro; Hiroe, Tetsuyuki; Fujiwara, Kazuhito; Yasushi, Kondo

    2008-11-01

    Visualization of explosion phenomena is very important and essential to evaluate the performance of explosive effects. The phenomena, however, generate blast waves and fragments from cases. We must protect our visualizing equipment from any form of impact. In the tests described here, the front lens was separated from the camera head by means of a fiber-optic cable in order to be able to use the camera, a Shimadzu Hypervision HPV-1, for tests in severe blast environment, including the filming of explosions. It was possible to obtain clear images of the explosion that were not inferior to the images taken by the camera with the lens directly coupled to the camera head. It could be confirmed that this system is very useful for the visualization of dangerous events, e.g., at an explosion site, and for visualizations at angles that would be unachievable under normal circumstances.

  20. Investigation of high speed phenomena

    NASA Technical Reports Server (NTRS)

    Becker, D. G.; Slattery, J. C.

    1972-01-01

    Experimental research is reported for laboratory simulation of meteors and meteoroid impacts on solid surfaces. Two types of mass measurements are discussed: impact ionization risetime effect, and luminous efficiency measurements.

  1. Electronic phenomena at high pressure

    SciTech Connect

    Drickamer, H.G.

    1981-01-01

    High pressure research is undertaken either to investigate intrinsically high pressure phenomena or in order to get a better understanding of the effect of the chemical environment on properties or processes at one atmosphere. Studies of electronic properties which fall in each area are presented. Many molecules and complexes can assume in the excited state different molecular arrangements and intermolecular forces depending on the medium. Their luminescence emission is then very different in a rigid or a fluid medium. With pressure one can vary the viscosity of the medium by a factor of 10/sup 7/ and thus control the distribution and rate of crossing between the excited state conformations. In rare earth chelates the efficiency of 4f-4f emission of the rare earth is controlled by the feeding from the singlet and triplet levels of the organic ligand. These ligand levels can be strongly shifted by pressure. A study of the effect of pressure on the emission efficiency permits one to understand the effect of ligand chemistry at one atmosphere. At high pressure electronic states can be sufficiently perturbed to provide new ground states. In EDA complexes these new ground states exhibit unusual chemical reactivity and new products.

  2. High speed handpieces

    PubMed Central

    Bhandary, Nayan; Desai, Asavari; Shetty, Y Bharath

    2014-01-01

    High speed instruments are versatile instruments used by clinicians of all specialties of dentistry. It is important for clinicians to understand the types of high speed handpieces available and the mechanism of working. The centers for disease control and prevention have issued guidelines time and again for disinfection and sterilization of high speed handpieces. This article presents the recent developments in the design of the high speed handpieces. With a view to prevent hospital associated infections significant importance has been given to disinfection, sterilization & maintenance of high speed handpieces. How to cite the article: Bhandary N, Desai A, Shetty YB. High speed handpieces. J Int Oral Health 2014;6(1):130-2. PMID:24653618

  3. High Speed Research Program

    NASA Technical Reports Server (NTRS)

    Anderson, Robert E.; Corsiglia, Victor R.; Schmitz, Frederic H. (Technical Monitor)

    1994-01-01

    An overview of the NASA High Speed Research Program will be presented from a NASA Headquarters perspective. The presentation will include the objectives of the program and an outline of major programmatic issues.

  4. High-Speed Photography

    SciTech Connect

    Paisley, D.L.; Schelev, M.Y.

    1998-08-01

    The applications of high-speed photography to a diverse set of subjects including inertial confinement fusion, laser surgical procedures, communications, automotive airbags, lightning etc. are briefly discussed. (AIP) {copyright} {ital 1998 Society of Photo-Optical Instrumentation Engineers.}

  5. High speed flywheel

    SciTech Connect

    McGrath, S.V.

    1990-01-01

    This invention relates generally to flywheels and relates more particularly to the construction of a high speed, low-mass flywheel. Flywheels with which this invention is to be compared include those constructed of circumferentially wound filaments or fibers held together by a matrix or bonding material. Flywheels of such construction are known to possess a relatively high hoop strength but a relatively low radial strength. Hoop-wound flywheels are, therefore, particularly susceptible to circumferential cracks, and the radial stress limitations of such a flywheel substantially limit its speed capabilities. It is an object of the present invention to provide a new and improved flywheel which experiences reduced radial stress at high operating speeds. Another object of the present invention is to provide flywheel whose construction allows for radial growth as flywheel speed increases while providing the necessary stiffness for transferring and maintaining kinetic energy within the flywheel. Still another object of the present invention is to provide a flywheel having concentrically-disposed component parts wherein rotation induced radial stresses at the interfaces of such component parts approach zero. Yet another object of the present invention is to provide a flywheel which is particularly well-suited for high speed applications. 5 figs.

  6. High Speed Ice Friction

    NASA Astrophysics Data System (ADS)

    Seymour-Pierce, Alexandra; Sammonds, Peter; Lishman, Ben

    2014-05-01

    Many different tribological experiments have been run to determine the frictional behaviour of ice at high speeds, ostensibly with the intention of applying results to everyday fields such as winter tyres and sports. However, experiments have only been conducted up to linear speeds of several metres a second, with few additional subject specific studies reaching speeds comparable to these applications. Experiments were conducted in the cold rooms of the Rock and Ice Physics Laboratory, UCL, on a custom built rotational tribometer based on previous literature designs. Preliminary results from experiments run at 2m/s for ice temperatures of 271 and 263K indicate that colder ice has a higher coefficient of friction, in accordance with the literature. These results will be presented, along with data from further experiments conducted at temperatures between 259-273K (in order to cover a wide range of the temperature dependent behaviour of ice) and speeds of 2-15m/s to produce a temperature-velocity-friction map for ice. The effect of temperature, speed and slider geometry on the deformation of ice will also be investigated. These speeds are approaching those exhibited by sports such as the luge (where athletes slide downhill on an icy track), placing the tribological work in context.

  7. High speed door assembly

    DOEpatents

    Shapiro, Carolyn

    1993-01-01

    A high speed door assembly, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

  8. High speed door assembly

    DOEpatents

    Shapiro, C.

    1993-04-27

    A high speed door assembly is described, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

  9. High Speed Vortex Flows

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Wilcox, Floyd J., Jr.; Bauer, Steven X. S.; Allen, Jerry M.

    2000-01-01

    A review of the research conducted at the National Aeronautics and Space Administration (NASA), Langley Research Center (LaRC) into high-speed vortex flows during the 1970s, 1980s, and 1990s is presented. The data reviewed is for flat plates, cavities, bodies, missiles, wings, and aircraft. These data are presented and discussed relative to the design of future vehicles. Also presented is a brief historical review of the extensive body of high-speed vortex flow research from the 1940s to the present in order to provide perspective of the NASA LaRC's high-speed research results. Data are presented which show the types of vortex structures which occur at supersonic speeds and the impact of these flow structures to vehicle performance and control is discussed. The data presented shows the presence of both small- and large scale vortex structures for a variety of vehicles, from missiles to transports. For cavities, the data show very complex multiple vortex structures exist at all combinations of cavity depth to length ratios and Mach number. The data for missiles show the existence of very strong interference effects between body and/or fin vortices and the downstream fins. It was shown that these vortex flow interference effects could be both positive and negative. Data are shown which highlights the effect that leading-edge sweep, leading-edge bluntness, wing thickness, location of maximum thickness, and camber has on the aerodynamics of and flow over delta wings. The observed flow fields for delta wings (i.e. separation bubble, classical vortex, vortex with shock, etc.) are discussed in the context of' aircraft design. And data have been shown that indicate that aerodynamic performance improvements are available by considering vortex flows as a primary design feature. Finally a discussing of a design approach for wings which utilize vortex flows for improved aerodynamic performance at supersonic speed is presented.

  10. High Speed Video Insertion

    NASA Astrophysics Data System (ADS)

    Janess, Don C.

    1984-11-01

    This paper describes a means of inserting alphanumeric characters and graphics into a high speed video signal and locking that signal to an IRIG B time code. A model V-91 IRIG processor, developed by Instrumentation Technology Systems under contract to Instrumentation Marketing Corporation has been designed to operate in conjunction with the NAC model FHS-200 High Speed Video Camera which operates at 200 fields per second. The system provides for synchronizing the vertical and horizontal drive signals such that the vertical sync precisely coincides with five millisecond transitions in the IRIG time code. Additionally, the unit allows for the insertion of an IRIG time message as well as other data and symbols.

  11. High speed multiphoton imaging

    NASA Astrophysics Data System (ADS)

    Li, Yongxiao; Brustle, Anne; Gautam, Vini; Cockburn, Ian; Gillespie, Cathy; Gaus, Katharina; Lee, Woei Ming

    2016-12-01

    Intravital multiphoton microscopy has emerged as a powerful technique to visualize cellular processes in-vivo. Real time processes revealed through live imaging provided many opportunities to capture cellular activities in living animals. The typical parameters that determine the performance of multiphoton microscopy are speed, field of view, 3D imaging and imaging depth; many of these are important to achieving data from in-vivo. Here, we provide a full exposition of the flexible polygon mirror based high speed laser scanning multiphoton imaging system, PCI-6110 card (National Instruments) and high speed analog frame grabber card (Matrox Solios eA/XA), which allows for rapid adjustments between frame rates i.e. 5 Hz to 50 Hz with 512 × 512 pixels. Furthermore, a motion correction algorithm is also used to mitigate motion artifacts. A customized control software called Pscan 1.0 is developed for the system. This is then followed by calibration of the imaging performance of the system and a series of quantitative in-vitro and in-vivo imaging in neuronal tissues and mice.

  12. High speed civil transport

    NASA Technical Reports Server (NTRS)

    Bogardus, Scott; Loper, Brent; Nauman, Chris; Page, Jeff; Parris, Rusty; Steinbach, Greg

    1990-01-01

    The design process of the High Speed Civil Transport (HSCT) combines existing technology with the expectation of future technology to create a Mach 3.0 transport. The HSCT was designed to have a range in excess of 6000 nautical miles and carry up to 300 passengers. This range will allow the HSCT to service the economically expanding Pacific Basin region. Effort was made in the design to enable the aircraft to use conventional airports with standard 12,000 foot runways. With a takeoff thrust of 250,000 pounds, the four supersonic through-flow engines will accelerate the HSCT to a cruise speed of Mach 3.0. The 679,000 pound (at takeoff) HSCT is designed to cruise at an altitude of 70,000 feet, flying above most atmospheric disturbances.

  13. An Undergraduate Experiment for the Measurement of the Speed of Sound in Air: Phenomena and Discussion

    ERIC Educational Resources Information Center

    Yang, Hujiang; Zhao, Xiaohong; Wang, Xin; Xiao, Jinghua

    2012-01-01

    In this paper, we present and discuss some phenomena in an undergraduate experiment for the measurement of the speed of sound in air. A square wave distorts when connected to a piezoelectric transducer. Moreover, the amplitude of the receiving signal varies with the driving frequency. Comparing with the Gibbs phenomenon, these phenomena can be…

  14. An Undergraduate Experiment for the Measurement of the Speed of Sound in Air: Phenomena and Discussion

    ERIC Educational Resources Information Center

    Yang, Hujiang; Zhao, Xiaohong; Wang, Xin; Xiao, Jinghua

    2012-01-01

    In this paper, we present and discuss some phenomena in an undergraduate experiment for the measurement of the speed of sound in air. A square wave distorts when connected to a piezoelectric transducer. Moreover, the amplitude of the receiving signal varies with the driving frequency. Comparing with the Gibbs phenomenon, these phenomena can be…

  15. Unstable phenomena of low speed compressible natural convection with open boundaries by multi-GPU implementation

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Hsiang; Fu, Wu-Shung; Tsubokura, Makoto

    2016-11-01

    Unstable phenomena of low speed compressible natural convection are investigated numerically. Geometry contains parallel square plates or single heated plate with open boundaries is taken into consideration. Numerical methods of the Roe scheme, preconditioning and dual time stepping matching the DP-LUR method are used for low speed compressible flow. The absorbing boundary condition and modified LODI method is adopted to solve open boundary problems. High performance parallel computation is achieved by multi-GPU implementation with CUDA platform. The effects of natural convection by isothermal plates facing upwards in air is then carried out by the methods mentioned above Unstable behaviors appeared upon certain Rayleigh number with characteristic length respect to the width of plates or height between plates.

  16. High speed flywheel

    DOEpatents

    McGrath, Stephen V.

    1991-01-01

    A flywheel for operation at high speeds utilizes two or more ringlike coments arranged in a spaced concentric relationship for rotation about an axis and an expansion device interposed between the components for accommodating radial growth of the components resulting from flywheel operation. The expansion device engages both of the ringlike components, and the structure of the expansion device ensures that it maintains its engagement with the components. In addition to its expansion-accommodating capacity, the expansion device also maintains flywheel stiffness during flywheel operation.

  17. High speed flywheel

    SciTech Connect

    McGrath, S.V.

    1991-05-07

    This patent describes a flywheel for operation at high speed which utilizes two or more ringlike components arranged in a spaced concentric relationship for rotation about an axis and an expansion device interposed between the components for accommodating radial growth of the components resulting from flywheel operation. The expansion device engages both of the ringlike components, and the structure of the expansion device ensures that it maintains its engagement with the components. In addition to its expansion-accommodating capacity, the expansion device also maintains flywheel stiffness during flywheel operation.

  18. High speed transient sampler

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A high speed sampler comprises a meandered sample transmission line for transmitting an input signal, a straight strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates along the transmission lines. The sampling gates comprise a four terminal diode bridge having a first strobe resistor connected from a first terminal of the bridge to the positive strobe line, a second strobe resistor coupled from the third terminal of the bridge to the negative strobe line, a tap connected to the second terminal of the bridge and to the sample transmission line, and a sample holding capacitor connected to the fourth terminal of the bridge. The resistance of the first and second strobe resistors is much higher than the signal transmission line impedance in the preferred system. This results in a sampling gate which applies a very small load on the sample transmission line and on the strobe generator. The sample holding capacitor is implemented using a smaller capacitor and a larger capacitor isolated from the smaller capacitor by resistance. The high speed sampler of the present invention is also characterized by other optimizations, including transmission line tap compensation, stepped impedance strobe line, a multi-layer physical layout, and unique strobe generator design. A plurality of banks of such samplers are controlled for concatenated or interleaved sample intervals to achieve long sample lengths or short sample spacing.

  19. High speed transient sampler

    DOEpatents

    McEwan, T.E.

    1995-11-28

    A high speed sampler comprises a meandered sample transmission line for transmitting an input signal, a straight strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates along the transmission lines. The sampling gates comprise a four terminal diode bridge having a first strobe resistor connected from a first terminal of the bridge to the positive strobe line, a second strobe resistor coupled from the third terminal of the bridge to the negative strobe line, a tap connected to the second terminal of the bridge and to the sample transmission line, and a sample holding capacitor connected to the fourth terminal of the bridge. The resistance of the first and second strobe resistors is much higher than the signal transmission line impedance in the preferred system. This results in a sampling gate which applies a very small load on the sample transmission line and on the strobe generator. The sample holding capacitor is implemented using a smaller capacitor and a larger capacitor isolated from the smaller capacitor by resistance. The high speed sampler of the present invention is also characterized by other optimizations, including transmission line tap compensation, stepped impedance strobe line, a multi-layer physical layout, and unique strobe generator design. A plurality of banks of such samplers are controlled for concatenated or interleaved sample intervals to achieve long sample lengths or short sample spacing. 17 figs.

  20. HIGH SPEED CAMERA

    DOEpatents

    Rogers, B.T. Jr.; Davis, W.C.

    1957-12-17

    This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

  1. High speed nozzles task

    NASA Technical Reports Server (NTRS)

    Hamed, Awatef

    1995-01-01

    Supersonic cruise exhaust nozzles for advanced applications are optimized for a high nozzle pressure ratio (NPR) at design supersonic cruise Mach number and altitude. The performance of these nozzles with large expansion ratios are severely degraded for operations at subsonic speeds near sea level for NPR significantly less than the design values. The prediction of over-expanded 2DCD nozzles performance is critical to evaluating the internal losses and to the optimization of the integrated vehicle and propulsion system performance. The reported research work was aimed at validating and assessing existing computational methods and turbulence models for predicting the flow characteristics and nozzle performance at over-expanded conditions. Flow simulations in 2DCD nozzles were performed using five different turbulence models. The results are compared with the experimental data for the wall pressure distribution and thrust and flow coefficients at over-expanded static conditions.

  2. High speed packet switching

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This document constitutes the final report prepared by Proteon, Inc. of Westborough, Massachusetts under contract NAS 5-30629 entitled High-Speed Packet Switching (SBIR 87-1, Phase 2) prepared for NASA-Greenbelt, Maryland. The primary goal of this research project is to use the results of the SBIR Phase 1 effort to develop a sound, expandable hardware and software router architecture capable of forwarding 25,000 packets per second through the router and passing 300 megabits per second on the router's internal busses. The work being delivered under this contract received its funding from three different sources: the SNIPE/RIG contract (Contract Number F30602-89-C-0014, CDRL Sequence Number A002), the SBIR contract, and Proteon. The SNIPE/RIG and SBIR contracts had many overlapping requirements, which allowed the research done under SNIPE/RIG to be applied to SBIR. Proteon funded all of the work to develop new router interfaces other than FDDI, in addition to funding the productization of the router itself. The router being delivered under SBIR will be a fully product-quality machine. The work done during this contract produced many significant findings and results, summarized here and explained in detail in later sections of this report. The SNIPE/RIG contract was completed. That contract had many overlapping requirements with the SBIR contract, and resulted in the successful demonstration and delivery of a high speed router. The development that took place during the SNIPE/RIG contract produced findings that included the choice of processor and an understanding of the issues surrounding inter processor communications in a multiprocessor environment. Many significant speed enhancements to the router software were made during that time. Under the SBIR contract (and with help from Proteon-funded work), it was found that a single processor router achieved a throughput significantly higher than originally anticipated. For this reason, a single processor router was

  3. Breakdown phenomena in high power klystrons

    SciTech Connect

    Vlieks, A.E.; Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Hoyt, E.W.; Lebacqz, J.V.; Lee, T.G.

    1988-03-01

    In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. Consequently many studies and tests were made to understand and alleviate window breakdown phenomena. Some of the results in this area, especially the effects of surface coatings, window materials and processing techniques and their effects on breakdown will be discussed. Another important source of klystron failure in the recent past at SLAC has been the puncturing of the high voltage ceramic insulator in the gun region. A way of alleviating this problem has been found although the actual cause of the puncturing is not yet clear. The ''practical'' solution to this breakdown process will be described and a possible mechanism for the puncturing will be presented. 9 refs., 5 figs., 3 tabs.

  4. High speed civil transport

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This report discusses the design and marketability of a next generation supersonic transport. Apogee Aeronautics Corporation has designated its High Speed Civil Transport (HSCT): Supercruiser HS-8. Since the beginning of the Concorde era, the general consensus has been that the proper time for the introduction of a next generation Supersonic Transport (SST) would depend upon the technical advances made in the areas of propulsion (reduction in emissions) and material composites (stronger, lighter materials). It is believed by many in the aerospace industry that these beforementioned technical advances lie on the horizon. With this being the case, this is the proper time to begin the design phase for the next generation HSCT. The design objective for a HSCT was to develop an aircraft that would be capable of transporting at least 250 passengers with baggage at a distance of 5500 nmi. The supersonic Mach number is currently unspecified. In addition, the design had to be marketable, cost effective, and certifiable. To achieve this goal, technical advances in the current SST's must be made, especially in the areas of aerodynamics and propulsion. As a result of these required aerodynamic advances, several different supersonic design concepts were reviewed.

  5. High speed transition prediction

    NASA Technical Reports Server (NTRS)

    Gasperas, Gediminis

    1992-01-01

    The main objective of this work period was to develop, acquire and apply state-of-the-art tools for the prediction of transition at high speeds at NASA Ames. Although various stability codes as well as basic state codes were acquired, the development of a new Parabolized Stability Equation (PSE) code was minimal. The time that was initially allocated for development was used on other tasks, in particular for the Leading Edge Suction problem, in acquiring proficiency in various graphics tools, and in applying these tools to evaluate various Navier-Stokes and Euler solutions. The second objective of this work period was to attend the Transition and Turbulence Workshop at NASA Langley in July and August, 1991. A report on the Workshop follows. From July 8, 1991 to August 2, 1991, the author participated in the Transition and Turbulence Workshop at NASA Langley. For purposes of interest here, analysis can be said to consist of solving simplified governing equations by various analytical methods, such as asymptotic methods, or by use of very meager computer resources. From the composition of the various groups at the Workshop, it can be seen that analytical methods are generally more popular in Great Britain than they are in the U.S., possibly due to historical factors and the lack of computer resources. Experimenters at the Workshop were mostly concerned with subsonic flows, and a number of demonstrations were provided, among which were a hot-wire experiment to probe the boundary layer on a rotating disc, a hot-wire rake to map a free shear layer behind a cylinder, and the use of heating strips on a flat plate to control instability waves and consequent transition. A highpoint of the demonstrations was the opportunity to observe the rather noisy 'quiet' supersonic pilot tunnel in operation.

  6. The high-speed camera ULTRACAM

    NASA Astrophysics Data System (ADS)

    Marsh, T. R.; Dhillon, V. S.

    2006-08-01

    ULTRACAM is a high-speed, tri-band CCD camera designed for observations of time variable celestial objects. Commissioned on the 4.2m WHT in La Palma, it has now been used for observations of many types of phenomena and objects including stellar occultations, accreting black-holes, neutron stars and white dwarfs, pulsars, eclipsing binaries and pulsating stars. In this paper we describe the salient features of ULTRACAM and discuss some of the results of its use.

  7. High Speed Metal Removal

    DTIC Science & Technology

    1982-10-01

    values showed an unusual wear pattern, so the cutting speed was lowered to 440 feet per minute. When the results of these tests were plotted, this curve...again showed unusual wear. From this chart. Figure 6, Page 16, values of 3100 square inches of machined area, at a surface speed of 440 feet per...G RA DE _ 5P0 / f— r- s FM _ 4 00 F r. /M IN / O F RF D _ ,0 22 i N. / RPV / UJ 3 0 0 0- t // / Q. / / — LU O < t / / LL / / W 2 0 0

  8. High speed metal removal

    NASA Astrophysics Data System (ADS)

    Pugh, R. F.; Pohl, R. F.

    1982-10-01

    Four types of steel (AISI 1340, 4140, 4340, and HF-1) which are commonly used in large caliber projectile manufacture were machined at different hardness ranges representing the as-forged and the heat treated condition with various ceramic tools using ceramic coated tungsten carbide as a reference. Results show that machining speeds can be increased significantly using present available tooling.

  9. Focused Mission High Speed Combatant

    DTIC Science & Technology

    2003-05-09

    hull types to determine which hull type best meets the requirements for the Focused Mission High Speed Combatant. The first step in the analysis...MAPC, uses parametric models and scaling to create high level designs of various hull types. The inputs are desired speed , range, payload, sea state...reached 10 SWATH vessels exhibit superior seakeeping at near zero speed compared to other hull forms 5 Assumes 2 equal-sized GE Gas Turbines 11

  10. High energy phenomena during solar flares

    NASA Astrophysics Data System (ADS)

    Correia, Emilia

    1989-11-01

    The main purpose is to analyze the characteristics of peculiar solar events that could be produced by ultrarelativistic electrons and try to define the new boundary conditions for the primary energy release during impulsive phase. It seems that submillimeter emission in solar flares is not a rare phenomenon, there is not much evidence, due to the lack of observations in this range of the spectrum. During May 1984 the Sun was observed at 90 GHz with high time resolution and high sensitivity, and evidence was obtained. The May 21, 1984 event, at 1326 UT is the best example of the high energy manifestation during the spectrum and gave us new boundary conditions for the physical phenomena in the Sun. The May 21 event required a detailed analysis of the current interpretation models and suggested the presence of relativistic electrons during the impulsive phase. In this case Syncrotron/inverse compton mechanism was suggested to explain submillimeter/x ray emission and short pulse duration. The new boundary conditions for primary energy release favored Tajima and Sakai's model, based in magnetic island coalescence theory.

  11. Some novel phenomena at high density

    NASA Astrophysics Data System (ADS)

    Berkowitz, Evan Scott

    Astrophysical environments probe matter in ways impossible on Earth. In particular, matter in compact objects are extraordinarily dense. In this thesis we discuss two phenomena that may occur at high density. First, we study toroidal topological solitons called vortons, which can occur in the kaon-condensed color-flavor-locked phase of high-density quark matter, a candidate phase for the core of some neutron stars. We show that vortons have a large radius compared to their thickness if their electrical charge is on the order of 104 times the fundamental charge. We show that shielding of electric fields by electrons dramatically reduces the size of a vorton. Second, we study an unusual phase of degenerate electrons and nonrelativistic Bose-condensed helium nuclei that may exist in helium white dwarfs. We show that this phase supports a previously-unknown gapless mode, known as the half-sound, that radically alters the material's specific heat, and can annihilate into neutrinos. We provide evidence that this neutrino radiation is negligible compared to the star's surface photoemission.

  12. Minimum rotation speed to prevent coning phenomena in compendium paddle dissolution apparatus.

    PubMed

    Higuchi, Mizuki; Yoshihashi, Yasuo; Tarada, Katsuhide; Sugano, Kiyohiko

    2014-12-18

    The purpose of the present study was to investigate the applicability of the Zwietering equation to coning phenomena which often occur during dissolution testing. The minimum rotation speed at which coning phenomena disappeared (no coning rpm, NCrpm) was experimentally determined for various particle and fluid properties in a compendium paddle apparatus with a round-bottom unbaffled vessel. The particle size, relative density and kinematic viscosity exponents in the Zwietering equation were optimized for NCrpm. The particle size and relative density exponents were found to be similar with those for the general tank configurations of cylindrical flat-bottom baffled vessels. However, the kinematic viscosity exponent was significantly different. The equation obtained in this study showed sufficient accuracy (r(2)=0.98, average error=12rpm) to estimate the occurrence of coning. The Zwietering equation was found to be applicable to the coning phenomena in the compendium paddle apparatus.

  13. High-Speed Electrochemical Imaging.

    PubMed

    Momotenko, Dmitry; Byers, Joshua C; McKelvey, Kim; Kang, Minkyung; Unwin, Patrick R

    2015-09-22

    The design, development, and application of high-speed scanning electrochemical probe microscopy is reported. The approach allows the acquisition of a series of high-resolution images (typically 1000 pixels μm(-2)) at rates approaching 4 seconds per frame, while collecting up to 8000 image pixels per second, about 1000 times faster than typical imaging speeds used up to now. The focus is on scanning electrochemical cell microscopy (SECCM), but the principles and practicalities are applicable to many electrochemical imaging methods. The versatility of the high-speed scan concept is demonstrated at a variety of substrates, including imaging the electroactivity of a patterned self-assembled monolayer on gold, visualization of chemical reactions occurring at single wall carbon nanotubes, and probing nanoscale electrocatalysts for water splitting. These studies provide movies of spatial variations of electrochemical fluxes as a function of potential and a platform for the further development of high speed scanning with other electrochemical imaging techniques.

  14. SEAL FOR HIGH SPEED CENTRIFUGE

    DOEpatents

    Skarstrom, C.W.

    1957-12-17

    A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

  15. Development of a Revolutionary High Speed Spindle

    NASA Technical Reports Server (NTRS)

    Agba, Emmanuel I.

    1999-01-01

    This report presents the development of a hydraulic motor driven spindle system to be employed for high speed machining of composite materials and metals. The spindle system is conceived to be easily retrofitted into conventional milling machines. The need for the hydraulic spindle arises because of the limitations placed on conventional electric motor driven spindles by the low cutting power and the presence of vibrational phenomena associated with voltage frequency at high rotational speeds. Also, the electric motors are usually large and expensive when power requirements are moderately high. In contrast, hydraulic motor driven spindles promise a distinct increase in spindle life over the conventional electric motor driven spindles. In this report, existing technologies applicable to spindle holder for severe operating conditions were reviewed, conceptual designs of spindle holder system were developed and evaluated, and a detailed design of an acceptable concept was conducted. Finally, a rapid prototype of the design was produced for design evaluation.

  16. Gated high speed optical detector

    NASA Technical Reports Server (NTRS)

    Green, S. I.; Carson, L. M.; Neal, G. W.

    1973-01-01

    The design, fabrication, and test of two gated, high speed optical detectors for use in high speed digital laser communication links are discussed. The optical detectors used a dynamic crossed field photomultiplier and electronics including dc bias and RF drive circuits, automatic remote synchronization circuits, automatic gain control circuits, and threshold detection circuits. The equipment is used to detect binary encoded signals from a mode locked neodynium laser.

  17. High speed optical networks

    NASA Astrophysics Data System (ADS)

    Frankel, Michael Y.; Livas, Jeff

    2005-02-01

    This overview will discuss core network technology and cost trade-offs inherent in choosing between "analog" architectures with high optical transparency, and ones heavily dependent on frequent "digital" signal regeneration. The exact balance will be related to the specific technology choices in each area outlined above, as well as the network needs such as node geographic spread, physical connectivity patterns, and demand loading. Over the course of a decade, optical networks have evolved from simple single-channel SONET regenerator-based links to multi-span multi-channel optically amplified ultra-long haul systems, fueled by high demand for bandwidth at reduced cost. In general, the cost of a well-designed high capacity system is dominated by the number of optical to electrical (OE) and electrical to optical (EO) conversions required. As the reach and channel capacity of the transport systems continued to increase, it became necessary to improve the granularity of the demand connections by introducing (optical add/drop multiplexers) OADMs. Thus, if a node requires only small demand connectivity, most of the optical channels are expressed through without regeneration (OEO). The network costs are correspondingly reduced, partially balanced by the increased cost of the OADM nodes. Lately, the industry has been aggressively pursuing a natural extension of this philosophy towards all-optical "analog" core networks, with each demand touching electrical digital circuitry only at the in/egress nodes. This is expected to produce a substantial elimination of OEO costs, increase in network capacity, and a notionally simpler operation and service turn-up. At the same time, such optical "analog" network requires a large amount of complicated hardware and software for monitoring and manipulating high bit rate optical signals. New and more complex modulation formats that provide resiliency to both optical noise and nonlinear propagation effects are important for extended

  18. Flexible high speed CODEC

    NASA Technical Reports Server (NTRS)

    Wernlund, James V.

    1993-01-01

    HARRIS, under contract with NASA Lewis, has developed a hard decision BCH (Bose-Chaudhuri-Hocquenghem) triple error correcting block CODEC ASIC, that can be used in either a bursted or continuous mode. the ASIC contains both encoder and decoder functions, programmable lock thresholds, and PSK related functions. The CODEC provides up to 4 dB of coding gain for data rates up to 300 Mbps. The overhead is selectable from 7/8 to 15/16 resulting in minimal band spreading, for a given BER. Many of the internal calculations are brought out enabling the CODEC to be incorporated in more complex designs. The ASIC has been tested in BPSK, QPSK and 16-ary PSK link simulators and found to perform to within 0.1 dB of theory for BER's of 10(exp -2) to 10(exp -9). The ASIC itself, being a hard decision CODEC, is not limited to PSK modulation formats. Unlike most hard decision CODEC's, the HARRIS CODEC doesn't upgrade BER performance significantly at high BER's but rather becomes transparent.

  19. High speed multiwire photon camera

    NASA Technical Reports Server (NTRS)

    Lacy, Jeffrey L. (Inventor)

    1991-01-01

    An improved multiwire proportional counter camera having particular utility in the field of clinical nuclear medicine imaging. The detector utilizes direct coupled, low impedance, high speed delay lines, the segments of which are capacitor-inductor networks. A pile-up rejection test is provided to reject confused events otherwise caused by multiple ionization events occuring during the readout window.

  20. High speed multiwire photon camera

    NASA Technical Reports Server (NTRS)

    Lacy, Jeffrey L. (Inventor)

    1989-01-01

    An improved multiwire proportional counter camera having particular utility in the field of clinical nuclear medicine imaging. The detector utilizes direct coupled, low impedance, high speed delay lines, the segments of which are capacitor-inductor networks. A pile-up rejection test is provided to reject confused events otherwise caused by multiple ionization events occurring during the readout window.

  1. Experiments on high speed ejectors

    NASA Technical Reports Server (NTRS)

    Wu, J. J.

    1986-01-01

    Experimental studies were conducted to investigate the flow and the performance of thrust augmenting ejectors for flight Mach numbers in the range of 0.5 to 0.8, primary air stagnation pressures up to 107 psig (738 kPa), and primary air stagnation temperatures up to 1250 F (677 C). The experiment verified the existence of the second solution ejector flow, where the flow after complete mixing is supersonic. Thrust augmentation in excess of 1.2 was demonstrated for both hot and cold primary jets. The experimental ejector performed better than the corresponding theoretical optimal first solution ejector, where the mixed flow is subsonic. Further studies are required to realize the full potential of the second solution ejector. The research program was started by the Flight Dynamics Research Corporation (FDRC) to investigate the characteristic of a high speed ejector which augments thrust of a jet at high flight speeds.

  2. Small Scale High Speed Turbomachinery

    NASA Technical Reports Server (NTRS)

    London, Adam P. (Inventor); Droppers, Lloyd J. (Inventor); Lehman, Matthew K. (Inventor); Mehra, Amitav (Inventor)

    2015-01-01

    A small scale, high speed turbomachine is described, as well as a process for manufacturing the turbomachine. The turbomachine is manufactured by diffusion bonding stacked sheets of metal foil, each of which has been pre-formed to correspond to a cross section of the turbomachine structure. The turbomachines include rotating elements as well as static structures. Using this process, turbomachines may be manufactured with rotating elements that have outer diameters of less than four inches in size, and/or blading heights of less than 0.1 inches. The rotating elements of the turbomachines are capable of rotating at speeds in excess of 150 feet per second. In addition, cooling features may be added internally to blading to facilitate cooling in high temperature operations.

  3. High Speed Photometry for BUSCA

    NASA Astrophysics Data System (ADS)

    Cordes, O.; Reif, K.

    The camera BUSCA (Bonn University Simultaneous CAmera) is a standard instrument at the 2.2m telescope at Calar Alto Observatory (Spain) since 2001. At the moment some modifications of BUSCA are planned and partially realised. One major goal is the replacement of the old thick CCDs in the blue, yellow-green, and near-infrared channels. The newer CCDs have better cosmetics and performance in sensitivity. The other goal is to replace the old "Heidelberg"-style controller with a newly designed controller with the main focus on high-speed readout and on an advanced windowing mechanism. We present a theoretical analysis of the new controller design and its advantage in high speed photometry of rapidly pulsating stars. As an example PG1605+072 was chosen which was observed with BUSCA before in 2001 and 2002.

  4. High-speed rotorcraft propulsion

    NASA Technical Reports Server (NTRS)

    Rutherford, John W.; Fitzpatrick, Robert E.

    1991-01-01

    Recently completed high-speed rotorcraft design studies for NASA provide the basis to assess technology needs for the development of these aircraft. Preliminary analysis of several concepts possessing helicopter-like hover characteristics and cruise capabilities in the 450 knot regime, led to the selection of two concepts for further study. The concepts selected included the Rotor/Wing and the Tilt Wing. The two unique concepts use turbofan and turboshaft engines respectively. Designs, based on current technology for each, established a baseline configuration from which technology trade studies could be conducted. Propulsion technology goals from the IHPTET program established the advanced technolgy year. Due to high-speed requirements, each concept possesses its own unique propulsion challenges. Trade studies indicate that achieving th IHPTET Phase III goals significantly improves the effectiveness of both concepts. Increased engine efficiency is particularly important to VTOL aircraft by reducing gross weight.

  5. Highly energetic phenomena in water electrolysis.

    PubMed

    Postnikov, A V; Uvarov, I V; Lokhanin, M V; Svetovoy, V B

    2016-12-16

    Water electrolysis performed in microsystems with a fast change of voltage polarity produces optically invisible nanobubbles containing H2 and O2 gases. In this form the gases are able to the reverse reaction of water formation. Here we report extreme phenomena observed in a millimeter-sized open system. Under a frequency of driving pulses above 100 kHz the process is accompanied by clicking sounds repeated every 50 ms or so. Fast video reveals that synchronously with the click a bubble is growing between the electrodes which reaches a size of 300 μm in 50 μs. Detailed dynamics of the system is monitored by means of a vibrometer by observing a piece of silicon floating above the electrodes. The energy of a single event is estimated as 0.3 μJ and a significant part of this energy is transformed into mechanical work moving the piece. The observations are explained by the combustion of hydrogen and oxygen mixture in the initial bubble with a diameter of about 40 μm. Unusual combustion mechanism supporting spontaneous ignition at room temperature is responsible for the process. The observed effect demonstrates a principal possibility to build a microscopic internal combustion engine.

  6. Highly energetic phenomena in water electrolysis

    PubMed Central

    Postnikov, A. V.; Uvarov, I. V.; Lokhanin, M. V.; Svetovoy, V. B.

    2016-01-01

    Water electrolysis performed in microsystems with a fast change of voltage polarity produces optically invisible nanobubbles containing H2 and O2 gases. In this form the gases are able to the reverse reaction of water formation. Here we report extreme phenomena observed in a millimeter-sized open system. Under a frequency of driving pulses above 100 kHz the process is accompanied by clicking sounds repeated every 50 ms or so. Fast video reveals that synchronously with the click a bubble is growing between the electrodes which reaches a size of 300 μm in 50 μs. Detailed dynamics of the system is monitored by means of a vibrometer by observing a piece of silicon floating above the electrodes. The energy of a single event is estimated as 0.3 μJ and a significant part of this energy is transformed into mechanical work moving the piece. The observations are explained by the combustion of hydrogen and oxygen mixture in the initial bubble with a diameter of about 40 μm. Unusual combustion mechanism supporting spontaneous ignition at room temperature is responsible for the process. The observed effect demonstrates a principal possibility to build a microscopic internal combustion engine. PMID:27982103

  7. Highly energetic phenomena in water electrolysis

    NASA Astrophysics Data System (ADS)

    Postnikov, A. V.; Uvarov, I. V.; Lokhanin, M. V.; Svetovoy, V. B.

    2016-12-01

    Water electrolysis performed in microsystems with a fast change of voltage polarity produces optically invisible nanobubbles containing H2 and O2 gases. In this form the gases are able to the reverse reaction of water formation. Here we report extreme phenomena observed in a millimeter-sized open system. Under a frequency of driving pulses above 100 kHz the process is accompanied by clicking sounds repeated every 50 ms or so. Fast video reveals that synchronously with the click a bubble is growing between the electrodes which reaches a size of 300 μm in 50 μs. Detailed dynamics of the system is monitored by means of a vibrometer by observing a piece of silicon floating above the electrodes. The energy of a single event is estimated as 0.3 μJ and a significant part of this energy is transformed into mechanical work moving the piece. The observations are explained by the combustion of hydrogen and oxygen mixture in the initial bubble with a diameter of about 40 μm. Unusual combustion mechanism supporting spontaneous ignition at room temperature is responsible for the process. The observed effect demonstrates a principal possibility to build a microscopic internal combustion engine.

  8. High-speed code validation

    NASA Technical Reports Server (NTRS)

    Barnwell, Richard W.; Rogers, R. Clayton; Pittman, James L.; Dwoyer, Douglas L.

    1987-01-01

    The topics are presented in viewgraph form and include the following: NFL body experiment; high-speed validation problems; 3-D Euler/Navier-Stokes inlet code; two-strut inlet configuration; pressure contours in two longitudinal planes; sidewall pressure distribution; pressure distribution on strut inner surface; inlet/forebody tests in 60 inch helium tunnel; pressure distributions on elliptical missile; code validations; small scale test apparatus; CARS nonintrusive measurements; optimized cone-derived waverider study; etc.

  9. High Speed Holographic Movie Camera

    NASA Astrophysics Data System (ADS)

    Hentschel, W.; Lauterborn, W.

    1985-08-01

    A high speed holographic movie camera system has been developed to investigate the dynamic behavior of cavitation bubbles in liquids. As a light source for holography, a high power multiply cavity-dumped argonion laser is used to record very long hologram series with framing rates up to 300 kHz. For separating successively recorded holograms, two spatial multiplexing techniques are applied simultaneously: rotation of the holographic plate or film and acousto-optic beam deflection. With the combination of these two techniques we achieve up to 4000 single holograms in one series.

  10. High Speed Holographic Movie Camera

    NASA Astrophysics Data System (ADS)

    Hentschel, W.; Lauterborn, W.

    1985-02-01

    A high speed holographic movie camera system has been developed in our laboratories at the Third Physical Institute of the University of Gdttingen. As a light source for holography a high power multiply cavity-dumped argonion laser is used to record very long hologram series with framing rates up to 300 kHz. For separating successively recorded holograms two spatial multiplexing techniques are applied simultaneously: rotating of the holographic plate or film and acousto-optic beam deflection. With the combination of these two techniques we achieve up to 4000 single holograms in one series.

  11. High-Speed TCP Testing

    NASA Technical Reports Server (NTRS)

    Brooks, David E.; Gassman, Holly; Beering, Dave R.; Welch, Arun; Hoder, Douglas J.; Ivancic, William D.

    1999-01-01

    Transmission Control Protocol (TCP) is the underlying protocol used within the Internet for reliable information transfer. As such, there is great interest to have all implementations of TCP efficiently interoperate. This is particularly important for links exhibiting long bandwidth-delay products. The tools exist to perform TCP analysis at low rates and low delays. However, for extremely high-rate and lone-delay links such as 622 Mbps over geosynchronous satellites, new tools and testing techniques are required. This paper describes the tools and techniques used to analyze and debug various TCP implementations over high-speed, long-delay links.

  12. Faster than "g", Revisited with High-Speed Imaging

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2012-01-01

    The introduction of modern high-speed cameras in physics teaching provides a tool not only for easy visualization, but also for quantitative analysis of many simple though fast occurring phenomena. As an example, we present a very well-known demonstration experiment--sometimes also discussed in the context of falling chimneys--which is commonly…

  13. Faster than "g", Revisited with High-Speed Imaging

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2012-01-01

    The introduction of modern high-speed cameras in physics teaching provides a tool not only for easy visualization, but also for quantitative analysis of many simple though fast occurring phenomena. As an example, we present a very well-known demonstration experiment--sometimes also discussed in the context of falling chimneys--which is commonly…

  14. Quiet High-Speed Fan

    NASA Technical Reports Server (NTRS)

    Lieber, Lysbeth; Repp, Russ; Weir, Donald S.

    1996-01-01

    A calibration of the acoustic and aerodynamic prediction methods was performed and a baseline fan definition was established and evaluated to support the quiet high speed fan program. A computational fluid dynamic analysis of the NASA QF-12 Fan rotor, using the DAWES flow simulation program was performed to demonstrate and verify the causes of the relatively poor aerodynamic performance observed during the fan test. In addition, the rotor flowfield characteristics were qualitatively compared to the acoustic measurements to identify the key acoustic characteristics of the flow. The V072 turbofan source noise prediction code was used to generate noise predictions for the TFE731-60 fan at three operating conditions and compared to experimental data. V072 results were also used in the Acoustic Radiation Code to generate far field noise for the TFE731-60 nacelle at three speed points for the blade passage tone. A full 3-D viscous flow simulation of the current production TFE731-60 fan rotor was performed with the DAWES flow analysis program. The DAWES analysis was used to estimate the onset of multiple pure tone noise, based on predictions of inlet shock position as a function of the rotor tip speed. Finally, the TFE731-60 fan rotor wake structure predicted by the DAWES program was used to define a redesigned stator with the leading edge configured to minimize the acoustic effects of rotor wake / stator interaction, without appreciably degrading performance.

  15. Merging of high speed argon plasma jets

    SciTech Connect

    Case, A.; Messer, S.; Brockington, S.; Wu, L.; Witherspoon, F. D.; Elton, R.

    2013-01-15

    Formation of an imploding plasma liner for the plasma liner experiment (PLX) requires individual plasma jets to merge into a quasi-spherical shell of plasma converging on the origin. Understanding dynamics of the merging process requires knowledge of the plasma phenomena involved. We present results from the study of the merging of three plasma jets in three dimensional geometry. The experiments were performed using HyperV Technologies Corp. 1 cm Minirailguns with a preionized argon plasma armature. The vacuum chamber partially reproduces the port geometry of the PLX chamber. Diagnostics include fast imaging, spectroscopy, interferometry, fast pressure probes, B-dot probes, and high speed spatially resolved photodiodes, permitting measurements of plasma density, temperature, velocity, stagnation pressure, magnetic field, and density gradients. These experimental results are compared with simulation results from the LSP 3D hybrid PIC code.

  16. High-speed phosphor thermometry.

    PubMed

    Fuhrmann, N; Baum, E; Brübach, J; Dreizler, A

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm.

  17. High-speed phosphor thermometry

    NASA Astrophysics Data System (ADS)

    Fuhrmann, N.; Baum, E.; Brübach, J.; Dreizler, A.

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm.

  18. Elementary particle physics and high energy phenomena

    SciTech Connect

    Barker, A.R.; Cumalat, J.P.; de Alwis, S.P.; DeGrand, T.A.; Ford, W.T.; Mahanthappa, K.T.; Nauenberg, U.; Rankin, P.; Smith, J.G.

    1992-06-01

    This report discusses the following research in high energy physics: the properties of the z neutral boson with the SLD detector; the research and development program for the SDC muon detector; the fixed-target k-decay experiments; the Rocky Mountain Consortium for HEP; high energy photoproduction of states containing heavy quarks; and electron-positron physics with the CLEO II and Mark II detectors. (LSP).

  19. High speed quantitative digital microscopy

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

    1984-01-01

    Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

  20. A high speed sequential decoder

    NASA Technical Reports Server (NTRS)

    Lum, H., Jr.

    1972-01-01

    The performance and theory of operation for the High Speed Hard Decision Sequential Decoder are delineated. The decoder is a forward error correction system which is capable of accepting data from binary-phase-shift-keyed and quadriphase-shift-keyed modems at input data rates up to 30 megabits per second. Test results show that the decoder is capable of maintaining a composite error rate of 0.00001 at an input E sub b/N sub o of 5.6 db. This performance has been obtained with minimum circuit complexity.

  1. High speed holographic digital recorder.

    PubMed

    Roberts, H N; Watkins, J W; Johnson, R H

    1974-04-01

    Concepts, feasibility experiments, and key component developments are described for a holographic digital record/reproduce system with the potential for 1.0 Gbit/sec rates and higher. Record rates of 500 Mbits/sec have been demonstrated with a ten-channel acoustooptic modulator array and a mode-locked, cavity-dumped argon-ion laser. Acoustooptic device technology has been advanced notably during the development of mode lockers, cavity dumpers, beam deflectors, and multichannel modulator arrays. The development of high speed multichannel photodetector arrays for the readout subsystem requires special attention. The feasibility of 1.0 Gbits/sec record rates has been demonstrated.

  2. Flexible high-speed CODEC

    NASA Technical Reports Server (NTRS)

    Segallis, Greg P.; Wernlund, Jim V.; Corry, Glen

    1993-01-01

    This report is prepared by Harris Government Communication Systems Division for NASA Lewis Research Center under contract NAS3-25087. It is written in accordance with SOW section 4.0 (d) as detailed in section 2.6. The purpose of this document is to provide a summary of the program, performance results and analysis, and a technical assessment. The purpose of this program was to develop a flexible, high-speed CODEC that provides substantial coding gain while maintaining bandwidth efficiency for use in both continuous and bursted data environments for a variety of applications.

  3. High speed quantitative digital microscopy

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

    1984-01-01

    Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

  4. Remote Transmission at High Speed

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Omni and NASA Test Operations at Stennis entered a Dual-Use Agreement to develop the FOTR-125, a 125 megabit-per-second fiber-optic transceiver that allows accurate digital recordings over a great distance. The transceiver s fiber-optic link can be as long as 25 kilometers. This makes it much longer than the standard coaxial link, which can be no longer than 50 meters.The FOTR-125 utilizes laser diode transmitter modules and integrated receivers for the optical interface. Two transmitters and two receivers are employed at each end of the link with automatic or manual switchover to maximize the reliability of the communications link. NASA uses the transceiver in Stennis High-Speed Data Acquisition System (HSDAS). The HSDAS consists of several identical systems installed on the Center s test stands to process all high-speed data related to its propulsion test programs. These transceivers allow the recorder and HSDAS controls to be located in the Test Control Center in a remote location while the digitizer is located on the test stand.

  5. (Studies of high energy phenomena using muons)

    SciTech Connect

    Not Available

    1991-01-01

    This report covers the activities of the NIU high energy physics group as supported by DOE contract FG02-91ER40641 during the period from March 1991 to December 1991. Our group has three main efforts. The first is the D0 experiment at the Fermilab proton-antiproton collider, with major emphasis on its muon system. The second is the involvement of a portion of the group in Fermilab Experiment 789. Finally, we are also members of the SDC collaboration at the SSC.

  6. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    1960-01-01

    High-Speed Schlieren Movies of Decelerators at Supersonic Speeds. Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps. [Entire movie available on DVD from CASI as Doc ID 20070030973. Contact help@sti.nasa.gov

  7. High-speed data search

    NASA Technical Reports Server (NTRS)

    Driscoll, James N.

    1994-01-01

    The high-speed data search system developed for KSC incorporates existing and emerging information retrieval technology to help a user intelligently and rapidly locate information found in large textual databases. This technology includes: natural language input; statistical ranking of retrieved information; an artificial intelligence concept called semantics, where 'surface level' knowledge found in text is used to improve the ranking of retrieved information; and relevance feedback, where user judgements about viewed information are used to automatically modify the search for further information. Semantics and relevance feedback are features of the system which are not available commercially. The system further demonstrates focus on paragraphs of information to decide relevance; and it can be used (without modification) to intelligently search all kinds of document collections, such as collections of legal documents medical documents, news stories, patents, and so forth. The purpose of this paper is to demonstrate the usefulness of statistical ranking, our semantic improvement, and relevance feedback.

  8. Flexible High Speed Codec (FHSC)

    NASA Technical Reports Server (NTRS)

    Segallis, G. P.; Wernlund, J. V.

    1991-01-01

    The ongoing NASA/Harris Flexible High Speed Codec (FHSC) program is described. The program objectives are to design and build an encoder decoder that allows operation in either burst or continuous modes at data rates of up to 300 megabits per second. The decoder handles both hard and soft decision decoding and can switch between modes on a burst by burst basis. Bandspreading is low since the code rate is greater than or equal to 7/8. The encoder and a hard decision decoder fit on a single application specific integrated circuit (ASIC) chip. A soft decision applique is implemented using 300 K emitter coupled logic (ECL) which can be easily translated to an ECL gate array.

  9. Preliminary study of high-speed machining

    SciTech Connect

    Jordan, R.E.

    1980-07-01

    The feasibility of a high speed machining process has been established for application to Bendix aluminum products, based upon information gained through visits to existing high speed machining facilities and by the completion of a representative Bendix part using this process. The need for an experimental high speed machining capability at Bendix for further process evaluation is established.

  10. High speed sampler and demultiplexer

    DOEpatents

    McEwan, T.E.

    1995-12-26

    A high speed sampling demultiplexer based on a plurality of sampler banks, each bank comprising a sample transmission line for transmitting an input signal, a strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates at respective positions along the sample transmission line for sampling the input signal in response to the strobe signal. Strobe control circuitry is coupled to the plurality of banks, and supplies a sequence of bank strobe signals to the strobe transmission lines in each of the plurality of banks, and includes circuits for controlling the timing of the bank strobe signals among the banks of samplers. Input circuitry is included for supplying the input signal to be sampled to the plurality of sample transmission lines in the respective banks. The strobe control circuitry can repetitively strobe the plurality of banks of samplers such that the banks of samplers are cycled to create a long sample length. Second tier demultiplexing circuitry is coupled to each of the samplers in the plurality of banks. The second tier demultiplexing circuitry senses the sample taken by the corresponding sampler each time the bank in which the sampler is found is strobed. A plurality of such samples can be stored by the second tier demultiplexing circuitry for later processing. Repetitive sampling with the high speed transient sampler induces an effect known as ``strobe kickout``. The sample transmission lines include structures which reduce strobe kickout to acceptable levels, generally 60 dB below the signal, by absorbing the kickout pulses before the next sampling repetition. 16 figs.

  11. High speed sampler and demultiplexer

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A high speed sampling demultiplexer based on a plurality of sampler banks, each bank comprising a sample transmission line for transmitting an input signal, a strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates at respective positions along the sample transmission line for sampling the input signal in response to the strobe signal. Strobe control circuitry is coupled to the plurality of banks, and supplies a sequence of bank strobe signals to the strobe transmission lines in each of the plurality of banks, and includes circuits for controlling the timing of the bank strobe signals among the banks of samplers. Input circuitry is included for supplying the input signal to be sampled to the plurality of sample transmission lines in the respective banks. The strobe control circuitry can repetitively strobe the plurality of banks of samplers such that the banks of samplers are cycled to create a long sample length. Second tier demultiplexing circuitry is coupled to each of the samplers in the plurality of banks. The second tier demultiplexing circuitry senses the sample taken by the corresponding sampler each time the bank in which the sampler is found is strobed. A plurality of such samples can be stored by the second tier demultiplexing circuitry for later processing. Repetitive sampling with the high speed transient sampler induces an effect known as "strobe kickout". The sample transmission lines include structures which reduce strobe kickout to acceptable levels, generally 60 dB below the signal, by absorbing the kickout pulses before the next sampling repetition.

  12. The use of high-speed imaging in education

    NASA Astrophysics Data System (ADS)

    Kleine, H.; McNamara, G.; Rayner, J.

    2017-02-01

    Recent improvements in camera technology and the associated improved access to high-speed camera equipment have made it possible to use high-speed imaging not only in a research environment but also specifically for educational purposes. This includes high-speed sequences that are created both with and for a target audience of students in high schools and universities. The primary goal is to engage students in scientific exploration by providing them with a tool that allows them to see and measure otherwise inaccessible phenomena. High-speed imaging has the potential to stimulate students' curiosity as the results are often surprising or may contradict initial assumptions. "Live" demonstrations in class or student- run experiments are highly suitable to have a profound influence on student learning. Another aspect is the production of high-speed images for demonstration purposes. While some of the approaches known from the application of high speed imaging in a research environment can simply be transferred, additional techniques must often be developed to make the results more easily accessible for the targeted audience. This paper describes a range of student-centered activities that can be undertaken which demonstrate how student engagement and learning can be enhanced through the use of high speed imaging using readily available technologies.

  13. ADVANCED HIGH SPEED PROGRAMMABLE PREFORMING

    SciTech Connect

    Norris Jr, Robert E; Lomax, Ronny D; Xiong, Fue; Dahl, Jeffrey S; Blanchard, Patrick J

    2010-01-01

    Polymer-matrix composites offer greater stiffness and strength per unit weight than conventional materials resulting in new opportunities for lightweighting of automotive and heavy vehicles. Other benefits include design flexibility, less corrosion susceptibility, and the ability to tailor properties to specific load requirements. However, widespread implementation of structural composites requires lower-cost manufacturing processes than those that are currently available. Advanced, directed-fiber preforming processes have demonstrated exceptional value for rapid preforming of large, glass-reinforced, automotive composite structures. This is due to process flexibility and inherently low material scrap rate. Hence directed fiber performing processes offer a low cost manufacturing methodology for producing preforms for a variety of structural automotive components. This paper describes work conducted at the Oak Ridge National Laboratory (ORNL), focused on the development and demonstration of a high speed chopper gun to enhance throughput capabilities. ORNL and the Automotive Composites Consortium (ACC) revised the design of a standard chopper gun to expand the operational envelope, enabling delivery of up to 20kg/min. A prototype unit was fabricated and used to demonstrate continuous chopping of multiple roving at high output over extended periods. In addition fiber handling system modifications were completed to sustain the high output the modified chopper affords. These hardware upgrades are documented along with results of process characterization and capabilities assessment.

  14. Hypereutectoid high-speed steels

    SciTech Connect

    Kremnev, L.S.

    1986-01-01

    Half of the tungsten and molybdenum contained in R6M5 and R18 steels is concentrated in the undissolved eutectic carbides hindering austenitic grain gowth in hardening and providing the necessary strength and impact strength. This article describes the tungsten-free low-alloy high-speed steel 11M5F with a chemical composition of 1.03-1.10% C, 5.2-5.7% Mo, 3.8-4.2% Cr, 1.3-1.7% V, 0.3-0.6% Si, and 0.3% Ce. The properties of 11M5F and R6M5 steels are examined and compared. The results of production and laboratory tests of the cutting properties of tools of the steels developed showed their high effectiveness, especially of 11M5F steel with 1% A1. The life of tools of the tungsten-free steels is two or three times greater than the life of tools of R6M5 steel.

  15. High speed imager test station

    DOEpatents

    Yates, G.J.; Albright, K.L.; Turko, B.T.

    1995-11-14

    A test station enables the performance of a solid state imager (herein called a focal plane array or FPA) to be determined at high image frame rates. A programmable waveform generator is adapted to generate clock pulses at determinable rates for clock light-induced charges from a FPA. The FPA is mounted on an imager header board for placing the imager in operable proximity to level shifters for receiving the clock pulses and outputting pulses effective to clock charge from the pixels forming the FPA. Each of the clock level shifters is driven by leading and trailing edge portions of the clock pulses to reduce power dissipation in the FPA. Analog circuits receive output charge pulses clocked from the FPA pixels. The analog circuits condition the charge pulses to cancel noise in the pulses and to determine and hold a peak value of the charge for digitizing. A high speed digitizer receives the peak signal value and outputs a digital representation of each one of the charge pulses. A video system then displays an image associated with the digital representation of the output charge pulses clocked from the FPA. In one embodiment, the FPA image is formatted to a standard video format for display on conventional video equipment. 12 figs.

  16. High speed imager test station

    DOEpatents

    Yates, George J.; Albright, Kevin L.; Turko, Bojan T.

    1995-01-01

    A test station enables the performance of a solid state imager (herein called a focal plane array or FPA) to be determined at high image frame rates. A programmable waveform generator is adapted to generate clock pulses at determinable rates for clock light-induced charges from a FPA. The FPA is mounted on an imager header board for placing the imager in operable proximity to level shifters for receiving the clock pulses and outputting pulses effective to clock charge from the pixels forming the FPA. Each of the clock level shifters is driven by leading and trailing edge portions of the clock pulses to reduce power dissipation in the FPA. Analog circuits receive output charge pulses clocked from the FPA pixels. The analog circuits condition the charge pulses to cancel noise in the pulses and to determine and hold a peak value of the charge for digitizing. A high speed digitizer receives the peak signal value and outputs a digital representation of each one of the charge pulses. A video system then displays an image associated with the digital representation of the output charge pulses clocked from the FPA. In one embodiment, the FPA image is formatted to a standard video format for display on conventional video equipment.

  17. High speed holographic cine-recorder

    NASA Astrophysics Data System (ADS)

    Snyder, Donald; Watts, David; Gordon, Joseph; Lysogorski, Charles; Powers, Aaron; Perry, John; Chenette, Eugene; Hudson, Roger; Young, Raymond

    2005-08-01

    Air Force Research Laboratory and North Dancer Labs researchers have completed the initial development and transition to operational use of a high-speed holographic movie system. This paper documents the first fully operational use of a novel and unique experimental capability for high-speed holographic movies and high-speed cinema interferometry. In this paper we document the initial experiments that were performed with the High Speed Holographic Recorder (HSHR) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the possibilities for high-speed cine-laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool. After successful integration and testing the system was delivered to Arnold Engineering Development Center.

  18. 8-Foot High Speed Tunnel

    NASA Technical Reports Server (NTRS)

    1936-01-01

    Control panel below the test section of the 8-Foot High Speed Tunnel (8-Foot HST). Authorized July 17, 1933, construction of the 8-Foot HST was paid for with funds from the Federal Public Works Administration. Manly Hood and Russell Robinson designed the unusual facility which could produce a 500 mph wind stream across an 8-Foot test section. The concrete shell was not part of the original design. Like most projects funded through New Deal programs, the PWA restricted the amount of money which could be spent on materials. The majority of funds were supposed to be expended on labor. Though originally, Hood and Robinson had planned a welded steel pressure vessel around the test section, PWA officials proposed the idea of concrete. This picture shows the test section inside the igloo-like structure with walls of 1-foot thick reinforced concrete. The thick walls were needed 'because of the Bernoulli effect, [which meant that] the text chamber had to withstand powerful, inwardly directed pressure. Operating personnel located inside the igloo were subjected to pressures equivalent to 10,000-foot altitude and had to wear oxygen masks and enter through airlocks. A heat exchanger removed the large quantities of heat generated by the big fan.'

  19. Experimental high-speed network

    NASA Astrophysics Data System (ADS)

    McNeill, Kevin M.; Klein, William P.; Vercillo, Richard; Alsafadi, Yasser H.; Parra, Miguel V.; Dallas, William J.

    1993-09-01

    Many existing local area networking protocols currently applied in medical imaging were originally designed for relatively low-speed, low-volume networking. These protocols utilize small packet sizes appropriate for text based communication. Local area networks of this type typically provide raw bandwidth under 125 MHz. These older network technologies are not optimized for the low delay, high data traffic environment of a totally digital radiology department. Some current implementations use point-to-point links when greater bandwidth is required. However, the use of point-to-point communications for a total digital radiology department network presents many disadvantages. This paper describes work on an experimental multi-access local area network called XFT. The work includes the protocol specification, and the design and implementation of network interface hardware and software. The protocol specifies the Physical and Data Link layers (OSI layers 1 & 2) for a fiber-optic based token ring providing a raw bandwidth of 500 MHz. The protocol design and implementation of the XFT interface hardware includes many features to optimize image transfer and provide flexibility for additional future enhancements which include: a modular hardware design supporting easy portability to a variety of host system buses, a versatile message buffer design providing 16 MB of memory, and the capability to extend the raw bandwidth of the network to 3.0 GHz.

  20. High speed all optical networks

    NASA Technical Reports Server (NTRS)

    Chlamtac, Imrich; Ganz, Aura

    1990-01-01

    An inherent problem of conventional point-to-point wide area network (WAN) architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. The first solution to wavelength division multiplexing (WDM) based WAN networks that overcomes this limitation is presented. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs. The principle of the Lightnet architecture is the construction and use of virtual topology networks, embedded in the original network in the wavelength domain. For this construction Lightnets utilize the new concept of lightpaths which constitute the links of the virtual topology. Lightpaths are all-optical, multihop, paths in the network that allow data to be switched through intermediate nodes using high throughput passive optical switches. The use of the virtual topologies and the associated switching design introduce a number of new ideas, which are discussed in detail.

  1. High-speed pressure clamp.

    PubMed

    Besch, Stephen R; Suchyna, Thomas; Sachs, Frederick

    2002-10-01

    We built a high-speed, pneumatic pressure clamp to stimulate patch-clamped membranes mechanically. The key control element is a newly designed differential valve that uses a single, nickel-plated piezoelectric bending element to control both pressure and vacuum. To minimize response time, the valve body was designed with minimum dead volume. The result is improved response time and stability with a threefold decrease in actuation latency. Tight valve clearances minimize the steady-state air flow, permitting us to use small resonant-piston pumps to supply pressure and vacuum. To protect the valve from water contamination in the event of a broken pipette, an optical sensor detects water entering the valve and increases pressure rapidly to clear the system. The open-loop time constant for pressure is 2.5 ms for a 100-mmHg step, and the closed-loop settling time is 500-600 micros. Valve actuation latency is 120 micros. The system performance is illustrated for mechanically induced changes in patch capacitance.

  2. High-speed Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Ackeret, J

    1936-01-01

    Wind tunnel construction and design is discussed especially in relation to subsonic and supersonic speeds. Reynolds Numbers and the theory of compressible flows are also taken into consideration in designing new tunnels.

  3. High speed imaging - An important industrial tool

    NASA Technical Reports Server (NTRS)

    Moore, Alton; Pinelli, Thomas E.

    1986-01-01

    High-speed photography, which is a rapid sequence of photographs that allow an event to be analyzed through the stoppage of motion or the production of slow-motion effects, is examined. In high-speed photography 16, 35, and 70 mm film and framing rates between 64-12,000 frames per second are utilized to measure such factors as angles, velocities, failure points, and deflections. The use of dual timing lamps in high-speed photography and the difficulties encountered with exposure and programming the camera and event are discussed. The application of video cameras to the recording of high-speed events is described.

  4. High-Speed Ring Bus

    NASA Technical Reports Server (NTRS)

    Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

    2010-01-01

    The high-speed ring bus at the Jet Propulsion Laboratory (JPL) allows for future growth trends in spacecraft seen with future scientific missions. This innovation constitutes an enhancement of the 1393 bus as documented in the Institute of Electrical and Electronics Engineers (IEEE) 1393-1999 standard for a spaceborne fiber-optic data bus. It allows for high-bandwidth and time synchronization of all nodes on the ring. The JPL ring bus allows for interconnection of active units with autonomous operation and increased fault handling at high bandwidths. It minimizes the flight software interface with an intelligent physical layer design that has few states to manage as well as simplified testability. The design will soon be documented in the AS-1393 standard (Serial Hi-Rel Ring Network for Aerospace Applications). The framework is designed for "Class A" spacecraft operation and provides redundant data paths. It is based on "fault containment regions" and "redundant functional regions (RFR)" and has a method for allocating cables that completely supports the redundancy in spacecraft design, allowing for a complete RFR to fail. This design reduces the mass of the bus by incorporating both the Control Unit and the Data Unit in the same hardware. The standard uses ATM (asynchronous transfer mode) packets, standardized by ITU-T, ANSI, ETSI, and the ATM Forum. The IEEE-1393 standard uses the UNI form of the packet and provides no protection for the data portion of the cell. The JPL design adds optional formatting to this data portion. This design extends fault protection beyond that of the interconnect. This includes adding protection to the data portion that is contained within the Bus Interface Units (BIUs) and by adding to the signal interface between the Data Host and the JPL 1393 Ring Bus. Data transfer on the ring bus does not involve a master or initiator. Following bus protocol, any BIU may transmit data on the ring whenever it has data received from its host. There

  5. High spatial resolution measurements of ram accelerator gas dynamic phenomena

    NASA Technical Reports Server (NTRS)

    Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

    1992-01-01

    High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

  6. High speed nano-metrology

    SciTech Connect

    Humphris, Andrew D. L.; Zhao Bin; Catto, David; Kohli, Priyanka; Howard-Knight, Jeremy P.; Hobbs, Jamie K.

    2011-04-15

    For manufacturing at the nanometre scale a method for rapid and accurate measurement of the resultant functional devices is required. Although atomic force microscopy (AFM) has the requisite spatial resolution, it is severely limited in scan speed, the resolution and repeatability of vertical and lateral measurements being degraded when speed is increased. Here we present a new approach to AFM that makes a direct and feedback-independent measurement of surface height using a laser interferometer focused onto the back of the AFM tip. Combining this direct height measurement with a passive, feedback-free method for maintaining tip-sample contact removes the constraint on scan speed that comes from the bandwidth of the z-feedback loop. Conventional laser reflection detection is used for feedback control, which now plays the role of minimising tip-sample forces, rather than producing the sample topography. Using the system in conjunction with a rapid scanner, true height images are obtained with areas up to (36 x 36) {mu}m{sup 2} at 1 image/second, suitable for in-line applications.

  7. Lightweight, high speed bearing balls: A concept

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1974-01-01

    Low mass bearing balls with hardened iron-plated surfaces can eliminate problems of low fatigue strength and flexure fatigue, and lead to increased life and reliability of high speed ball bearings. Low mass balls exert lower centrifugal forces on outer race of bearing thus eliminating detrimental effect of high speed operation.

  8. High Speed Video for Airborne Instrumentation Application

    NASA Technical Reports Server (NTRS)

    Tseng, Ting; Reaves, Matthew; Mauldin, Kendall

    2006-01-01

    A flight-worthy high speed color video system has been developed. Extensive system development and ground and environmental. testing hes yielded a flight qualified High Speed Video System (HSVS), This HSVS was initially used on the F-15B #836 for the Lifting Insulating Foam Trajectory (LIFT) project.

  9. Reducing Heating In High-Speed Cinematography

    NASA Technical Reports Server (NTRS)

    Slater, Howard A.

    1989-01-01

    Infrared-absorbing and infrared-reflecting glass filters simple and effective means for reducing rise in temperature during high-speed motion-picture photography. "Hot-mirror" and "cold-mirror" configurations, employed in projection of images, helps prevent excessive heating of scenes by powerful lamps used in high-speed photography.

  10. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  11. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  12. High speed flow past wings

    NASA Technical Reports Server (NTRS)

    Norstrud, H.

    1973-01-01

    The analytical solution to the transonic small perturbation equation which describes steady compressible flow past finite wings at subsonic speeds can be expressed as a nonlinear integral equation with the perturbation velocity potential as the unknown function. This known formulation is substituted by a system of nonlinear algebraic equations to which various methods are applicable for its solution. Due to the presence of mathematical discontinuities in the flow solutions, however, a main computational difficulty was to ensure uniqueness of the solutions when local velocities on the wing exceeded the speed of sound. For continuous solutions this was achieved by embedding the algebraic system in an one-parameter operator homotopy in order to apply the method of parametric differentiation. The solution to the initial system of equations appears then as a solution to a Cauchy problem where the initial condition is related to the accompanying incompressible flow solution. In using this technique, however, a continuous dependence of the solution development on the initial data is lost when the solution reaches the minimum bifurcation point. A steepest descent iteration technique was therefore, added to the computational scheme for the calculation of discontinuous flow solutions. Results for purely subsonic flows and supersonic flows with and without compression shocks are given and compared with other available theoretical solutions.

  13. High Speed Dynamics in Brittle Materials

    NASA Astrophysics Data System (ADS)

    Hiermaier, Stefan

    2015-06-01

    Brittle Materials under High Speed and Shock loading provide a continuous challenge in experimental physics, analysis and numerical modelling, and consequently for engineering design. The dependence of damage and fracture processes on material-inherent length and time scales, the influence of defects, rate-dependent material properties and inertia effects on different scales make their understanding a true multi-scale problem. In addition, it is not uncommon that materials show a transition from ductile to brittle behavior when the loading rate is increased. A particular case is spallation, a brittle tensile failure induced by the interaction of stress waves leading to a sudden change from compressive to tensile loading states that can be invoked in various materials. This contribution highlights typical phenomena occurring when brittle materials are exposed to high loading rates in applications such as blast and impact on protective structures, or meteorite impact on geological materials. A short review on experimental methods that are used for dynamic characterization of brittle materials will be given. A close interaction of experimental analysis and numerical simulation has turned out to be very helpful in analyzing experimental results. For this purpose, adequate numerical methods are required. Cohesive zone models are one possible method for the analysis of brittle failure as long as some degree of tension is present. Their recent successful application for meso-mechanical simulations of concrete in Hopkinson-type spallation tests provides new insight into the dynamic failure process. Failure under compressive loading is a particular challenge for numerical simulations as it involves crushing of material which in turn influences stress states in other parts of a structure. On a continuum scale, it can be modeled using more or less complex plasticity models combined with failure surfaces, as will be demonstrated for ceramics. Models which take microstructural

  14. Thermomagnetic phenomena in the mixed state of high temperature superconductors

    NASA Technical Reports Server (NTRS)

    Meilikhov, E. Z.

    1995-01-01

    Galvano- and thermomagnetic-phenomena in high temperature superconductors, based on kinetic coefficients, are discussed, along with a connection between the electric field and the heat flow in superconductor mixed state. The relationship that determines the transport coefficients of high temperature superconductors in the mixed state based on Seebeck and Nernst effects is developed. It is shown that this relationship is true for a whole transition region of the resistive mixed state of a superconductor. Peltier, Ettingshausen and Righi-Leduc effects associated with heat conductivity as related to high temperature superconductors are also addressed.

  15. Active control system for high speed windmills

    DOEpatents

    Avery, Don E.

    1988-01-01

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

  16. Active control system for high speed windmills

    DOEpatents

    Avery, D.E.

    1988-01-12

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

  17. The VK-8L High - Speed Camera

    NASA Astrophysics Data System (ADS)

    Venatovsky, I. V.; Tsukanov, A. A.; Kirillov, V. A.

    1985-02-01

    To enhance the time resolution of high-speed cine equipment during the investigation of rapidly flowing processes, a light source to illumi late an object under test is represented b7 solid-state laser exposure devices operating in the mode of Q-factor flodulation. With a high-speed eine cafiera being run in the continuous scanning mode, these devices will permit a sequence of fra Mlles to be obtained within a short exposure time of 150 ns to 200 nanoseconds. At scanning speeds of up to 250 m/s this will ensure satisfactory image quality from the slear viewpoint. In the case of faster continuous scanuin speeds and of shorter exposure times, it becomes necessary to run the high-speed cauera in the fl ode of frame-by-frame cinematography.

  18. Thermodynamics and Transport Phenomena in High Temperature Steam Electrolysis Cells

    SciTech Connect

    James E. O'Brien

    2012-03-01

    Hydrogen can be produced from water splitting with relatively high efficiency using high temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high temperature process heat. The overall thermal-to-hydrogen efficiency for high temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. An overview of high temperature electrolysis technology will be presented, including basic thermodynamics, experimental methods, heat and mass transfer phenomena, and computational fluid dynamics modeling.

  19. ERROR CORRECTION IN HIGH SPEED ARITHMETIC,

    DTIC Science & Technology

    The errors due to a faulty high speed multiplier are shown to be iterative in nature. These errors are analyzed in various aspects. The arithmetic coding technique is suggested for the improvement of high speed multiplier reliability. Through a number theoretic investigation, a large class of arithmetic codes for single iterative error correction are developed. The codes are shown to have near-optimal rates and to render a simple decoding method. The implementation of these codes seems highly practical. (Author)

  20. Lubrication and cooling for high speed gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1985-01-01

    The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

  1. Speed control with end cushion for high speed air cylinder

    DOEpatents

    Stevens, Wayne W.; Solbrig, Charles W.

    1991-01-01

    A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

  2. Optical Diagnostics of Nonequilibrium Phenomena in Highly Rarefied Gas Flows

    NASA Astrophysics Data System (ADS)

    Niimi, Tomohide

    2003-05-01

    The necessity of non-intrusive measurement of the thermodynamic variables in rarefied gas flows has motivated the development of optical diagnostics, such as electron beam fluorescence, laser induced fluorescence, coherent anti-Stokes Raman scattering, and so on. These spectroscopic methods have enabled to detect the nonequilibrium in the gas flows, based on the internal energy distributions obtained from spectral profiles. In this paper, the laser-based techniques for detection of the nonequilibrium phenomena in the highly rarefied gas flows and some results obtained by us are described.

  3. Agile Electromagnetics Exploiting High Speed Logic (AEEHSL).

    DTIC Science & Technology

    2014-09-26

    examination and alteration of codes and filter weights 3. READ Mode - This mode enables the reading or replaying of the data from the digital tape recorder...available in this subsystems are used to initialize the * radar, clock the code from the high-speed code storage memory to drive the code modulator, delay...correlation process. There is storage space within the high speed memory for 32 codes of length 64 bits or less. The radiated code can be changed by a

  4. High-speed mirror-scanning tracker

    NASA Astrophysics Data System (ADS)

    Tong, HengWei

    1999-06-01

    This paper introduces a high speed single-mirror scanner developed by us as a versatile tracker. It can be connected with a high speed camera, a TV tracker (or color video recorder) /measurer/recorder. It can be guided by a computer, a joystick (automatic or manual) or TV tracker. In this paper, we also present the advantages of our scanner contrasted with the limitations of fixed camera system. In addition, several usable projects of mirror scanner are discussed.

  5. A High Vacuum High Speed Ion Pump

    DOE R&D Accomplishments Database

    Foster, J. S. Jr.; Lawrence, E. O.; Lofgren, E. J.

    1952-08-27

    A vacuum pump based on the properties of a magnetically collimated electric discharge is described. It has a speed in the range 3000 to 7000 liters a second and a base pressure in the order of 10{sup -6} mm. (auth)

  6. Unusual gyroscopic system eigenvalue behavior in high-speed planetary gears

    NASA Astrophysics Data System (ADS)

    Cooley, Christopher G.; Parker, Robert G.

    2013-04-01

    This study demonstrates unusual gyroscopic system eigenvalue behavior observed in a lumped-parameter planetary gear model. While the model has been used for dynamic analyses in industrial applications, the focus is on the eigenvalue phenomena that occur at especially high speeds rather than practical planetary gear behavior. The behaviors include calculation of exact trajectories across critical speeds, uncommon stability features near degenerate critical speeds, and unique stability transitions. These eigenvalue behaviors are not evident in the vast literature on gyroscopic systems.

  7. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - A Hennessey Venom GT stands on the 3.5-mile long runway between test runs at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  8. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - An engineer readies a Hennessey Venom GT for test runs on the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  9. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - Mechanics and engineers ready a Hennessey Venom GT for test runs on the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  10. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - Mechanics, engineers and Driver Brian Smith, in jumpsuit, ready a Hennessey Venom GT for test runs on the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  11. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - The Performance Power Racing and Hennessey Performance teams pose with a Hennessey Venom GT at the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The teams are, from left, Hennessey's John Heinricy, John Hennessey, Brian Smith, Performance Power Racing's Johnny Bohmer, Matt Lundy and Jeff McEachran. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles.

  12. High-speed oblique drop impact on thin liquid films

    NASA Astrophysics Data System (ADS)

    Guo, Yisen; Lian, Yongsheng

    2017-08-01

    We numerically investigate high-speed drop impact on thin liquid films with a focus on oblique impact. The flow behavior is described by solving the incompressible Navier-Stokes equations using the variable density pressure projection method. The phase interfaces are captured using the moment-of-fluid method. The numerical method is validated against experiments and theoretical predictions. Our study on high-speed oblique impact reveals that the tangential velocity can significantly alter impact phenomena: a higher tangential velocity leads to a lower lamella height and radius on the side behind the advancing drop, and the higher tangential velocity also leads to stronger vortices at the drop and film interface due to Kelvin-Helmholtz instability. Our investigation on the effect of liquid film thickness shows that a thinner liquid film leads to an earlier crown breakup. Last, our study shows that lowering the film density can prompt earlier splashing.

  13. Machine Vision Techniques For High Speed Videography

    NASA Astrophysics Data System (ADS)

    Hunter, David B.

    1984-11-01

    The priority associated with U.S. efforts to increase productivity has led to, among other things, the development of Machine Vision systems for use in manufacturing automation requirements. Many such systems combine solid state television cameras and data processing equipment to facilitate high speed, on-line inspection and real time dimensional measurement of parts and assemblies. These parts are often randomly oriented and spaced on a conveyor belt under continuous motion. Television imagery of high speed events has historically been achieved by use of pulsed (strobe) illumination or high speed shutter techniques synchronized with a camera's vertical blanking to separate write and read cycle operation. Lack of synchronization between part position and camera scanning in most on-line applications precludes use of this vertical interval illumination technique. Alternatively, many Machine Vision cameras incorporate special techniques for asynchronous, stop-motion imaging. Such cameras are capable of imaging parts asynchronously at rates approaching 60 hertz while remaining compatible with standard video recording units. Techniques for asynchronous, stop-motion imaging have not been incorporated in cameras used for High Speed Videography. Imaging of these events has alternatively been obtained through the utilization of special, high frame rate cameras to minimize motion during the frame interval. High frame rate cameras must undoubtedly be utilized for recording of high speed events occurring at high repetition rates. However, such cameras require very specialized, and often expensive, video recording equipment. It seems, therefore, that Machine Vision cameras with capability for asynchronous, stop-motion imaging represent a viable approach for cost effective video recording of high speed events occurring at repetition rates up to 60 hertz.

  14. High speed flight effects on noise propagation

    NASA Astrophysics Data System (ADS)

    Burrin, R. H.; Ahuja, K. K.; Salikuddin, M.

    1987-01-01

    An experimental study to investigate the effects of source motion on sound propagation at high Mach numbers was devised to determine, in particular, if the large amplifications in the forward arc to high speeds, predicted by the 'convective amplification' factors normally used for low speeds, are realistic. An acoustic point source and a microphone, both immersed in flows up to a Mach number of 0.8, were used to obtain the convective amplification factors for comparison with predictions. The results confirmed the existence of high levels of noise propagating ahead of an aircraft flying at high speed. The commonly adopted prediction formula, namely (1 - M sub 0 cos theta sub E) exp -4, was categorically confirmed by the data for frequencies up to 5 kHz and Mach numbers of 0.2 to 0.8. At higher frequencies, the predictions are followed up to emission angles of 120 deg, but then deviate downward towards the direction of flight.

  15. Scientific Visualization in High Speed Network Environments

    NASA Technical Reports Server (NTRS)

    Vaziri, Arsi; Kutler, Paul (Technical Monitor)

    1997-01-01

    In several cases, new visualization techniques have vastly increased the researcher's ability to analyze and comprehend data. Similarly, the role of networks in providing an efficient supercomputing environment have become more critical and continue to grow at a faster rate than the increase in the processing capabilities of supercomputers. A close relationship between scientific visualization and high-speed networks in providing an important link to support efficient supercomputing is identified. The two technologies are driven by the increasing complexities and volume of supercomputer data. The interaction of scientific visualization and high-speed networks in a Computational Fluid Dynamics simulation/visualization environment are given. Current capabilities supported by high speed networks, supercomputers, and high-performance graphics workstations at the Numerical Aerodynamic Simulation Facility (NAS) at NASA Ames Research Center are described. Applied research in providing a supercomputer visualization environment to support future computational requirements are summarized.

  16. Exploring High-Energy Phenomena in Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Chilingarian, Ashot A.

    2013-12-01

    The study of high-energy phenomena in the atmosphere provides unique information about particle acceleration and multiplication in the lower and upper atmosphere during thunderstorms. Generation and propagation of large fluxes of electrons, positrons, gamma rays, and neutrons in the atmosphere and in near space are related to the development of thunderstorms and may be used for monitoring dangerous consequences of extreme weather. Electromagnetic emissions connected with thunderstorms trigger various dynamic processes in the Earth's magnetosphere, causing global geomagnetic storms and changing electrodynamics properties of the ionosphere. The large fluences of energetic electrons, photons, and neutrons produced by runaway electron avalanches can potentially be a danger to aircraft crews, passengers, and onboard electronic systems.

  17. a Unified Model of High-Energy Astrophysical Phenomena

    NASA Astrophysics Data System (ADS)

    de Rújula, A.

    I outline a unified model of high-energy astrophysics, in which the gamma background radiation, cluster "cooling flows", gamma-ray bursts, X-ray flashes and cosmic-ray electrons and nuclei of all energies — share a common origin. The mechanism underlying these phenomena is the emission of relativistic "cannonballs" by ordinary supernovae, analogous to the observed ejection of plasmoids by quasars and microquasars. I concentrate on Cosmic Rays: the longest-lasting conundrum in astrophysics. The distribution of Cosmic Rays in the Galaxy, their total "luminosity", the broken power-law spectra with their observed slopes, the position of the knee(s) and ankle(s), and the alleged variations of composition with energy are all explained in terms of simple and "standard" physics. The model is only lacking a satisfactory theoretical understanding of the "cannon" that emits the cannonballs in catastrophic episodes of accretion onto a compact object.

  18. High speed hydrogen/graphite interaction

    NASA Technical Reports Server (NTRS)

    Kelly, A. J.; Hamman, R.; Sharma, O. P.; Harrje, D. T.

    1974-01-01

    Various aspects of a research program on high speed hydrogen/graphite interaction are presented. Major areas discussed are: (1) theoretical predictions of hydrogen/graphite erosion rates; (2) high temperature, nonequilibrium hydrogen flow in a nozzle; and (3) molecular beam studies of hydrogen/graphite erosion.

  19. High Speed Digital Camera Technology Review

    NASA Technical Reports Server (NTRS)

    Clements, Sandra D.

    2009-01-01

    A High Speed Digital Camera Technology Review (HSD Review) is being conducted to evaluate the state-of-the-shelf in this rapidly progressing industry. Five HSD cameras supplied by four camera manufacturers participated in a Field Test during the Space Shuttle Discovery STS-128 launch. Each camera was also subjected to Bench Tests in the ASRC Imaging Development Laboratory. Evaluation of the data from the Field and Bench Tests is underway. Representatives from the imaging communities at NASA / KSC and the Optical Systems Group are participating as reviewers. A High Speed Digital Video Camera Draft Specification was updated to address Shuttle engineering imagery requirements based on findings from this HSD Review. This draft specification will serve as the template for a High Speed Digital Video Camera Specification to be developed for the wider OSG imaging community under OSG Task OS-33.

  20. DAC 22 High Speed Civil Transport Model

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Between tests, NASA research engineer Dave Hahne inspects a tenth-scale model of a supersonic transport model in the 30- by 60-Foot Tunnel at NASA Langley Research Center, Hampton, Virginia. The model is being used in support of NASA's High-Speed Research (HSR) program. Langley researchers are applying advance aerodynamic design methods to develop a wing leading-edge flap system which significantly improves low-speed fuel efficiency and reduces noise generated during takeoff operation. Langley is NASA's lead center for the agency's HSR program, aimed at developing technology to help U.S. industry compete in the rapidly expanding trans-oceanic transport market. A U.S. high-speed civil transport is expected to fly in about the year 2010. As envisioned, it would fly 300 passengers across the Pacific in about four hours at Mach 2.4 (approximately 1,600 mph/1950 kph) for a modest increase over business class fares.

  1. Numerical investigation of the flow phenomena around a low specific speed Francis turbine's guide vane cascade

    NASA Astrophysics Data System (ADS)

    Chitrakar, Sailesh; Singh Thapa, Biraj; Dahlhaug, Ole Gunnar; Prasad Neopane, Hari

    2016-11-01

    Guide vanes of Francis turbines convey a significant influence on the flow field at the inlet of the runner. This influence is in the form of pressure pulsation, caused due to rotor-stator-interaction. A guide vane cascade containing a single blade passage was developed to predict the flow field experimentally. Firstly, this paper investigates flow phenomena around the guide vane cascade through computational techniques. A numerical model is prepared with three different turbulence models. The velocity distribution obtained from these models are compared with experimental results at two circumferential midspan locations. Secondly, the influence of increasing the clearance gap on the flow is studied. Such gaps are expected to increase when the flow containing eroding particles passes through the turbine. This paper also shows that the pressure difference between the pressure and the suction side of guide vane influences the leakage flow through the gap. Hence, reduction of the pressure gradient will reduce leakages through clearance gaps, hereby condensing the subsequent effect of pressure pulsations and erosion. This study also shows that the effect of the gap is prominent in the near wall regions which are close to the gap, whereas it dissipates gradually towards the midspan.

  2. High Speed and Slow Motion: The Technology of Modern High Speed Cameras

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2011-01-01

    The enormous progress in the fields of microsystem technology, microelectronics and computer science has led to the development of powerful high speed cameras. Recently a number of such cameras became available as low cost consumer products which can also be used for the teaching of physics. The technology of high speed cameras is discussed,…

  3. High Speed and Slow Motion: The Technology of Modern High Speed Cameras

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2011-01-01

    The enormous progress in the fields of microsystem technology, microelectronics and computer science has led to the development of powerful high speed cameras. Recently a number of such cameras became available as low cost consumer products which can also be used for the teaching of physics. The technology of high speed cameras is discussed,…

  4. Phenomena and Performance of High-Efficiency Split Spectrum Photovoltaics

    NASA Astrophysics Data System (ADS)

    Downs, Chandler

    High-efficiency photovoltaics are one of the most promising technologies for supplying sustainable energy in the near future. These technologies allow for high energy conversion efficiencies and long system lifetimes, which is becoming an increasingly profitable power generation option. One high-efficiency photovoltaic technology gaining increasing attention recent years is that of split-spectrum photovoltaics. This technology divides the incident solar spectrum on the basis of wavelength, directing each portion of the spectrum to a different cell where the light can be utilized most efficiently. In this dissertation, a number of aspects of high-efficiency photovoltaics, most notably split-spectrum photovoltaics, are examined. First, the ideal bandgap placements of the subcells of a split-spectrum photovoltaic system are calculated, specifically determined with an eye towards practical fabrication of the cells. Two viable designs are determined which improve theoretical absolute conversion efficiency by 4-5%. Next, those systems are simulated using the TCAD Sentaurus software package to project conversion efficiencies and determine additional device specifications (doping levels, layer thicknesses, etc.). These cells show comparable conversion efficiencies to high performing, full-spectrum multijunction photovoltaics in fabrication today. In the last section, a theoretical examination of semiconductor performance under high optical concentration is performed, including the prediction and characterization of various phenomena in those devices. This work aims to improve the understanding of the performance of high concentration photovoltaics, most notably split-spectrum photovoltaics. This understanding will aid in the advancement of this technology as a widespread, sustainable energy source for use worldwide, reducing greenhouse emissions and providing cheap, clean energy.

  5. High speed technology development and evaluation

    NASA Astrophysics Data System (ADS)

    Parker, D. R.; Brown, E. R.; Dickson, J. F.

    1986-10-01

    Semiconductor technology suited to high on-board data handling rates was investigated. Very high speed discrete logic and high speed gate arrays; single chip digital signal processors and single chip floating point processing peripherals; and analog CCD technologies and custom designed CCD chips for synthetic aperture radar applications were assessed. The 2 micron CMOS technology is highly reliable, supporting semicustom design techniques. Process JGC, the CCD technology, is highly reliable except for tolerance to ionizing radiation. Reliability of the ECL 16-bit serial-parallel parallel-serial converter junction isolated bipolar process, process WZA, is compromised by a design error and oxide contamination contributing to high leakage levels. The bipolar circuit is tolerant to an ionizing radiation of 20kRad. Step stress environmental testing to 200 C produces no failures in CMOS and CCD technologies, but accelerates the degradation of the oxide contaminated bipolar process. All technologies are susceptible to single event upsets.

  6. New High-Energy Phenomena in Aircraft Triggered Lightning

    NASA Astrophysics Data System (ADS)

    Kochkin, P.; Van Deursen, A.; de Boer, A.; Bardet, M.; Boissin, J. F.

    2016-12-01

    High-energy phenomena associated with lighting have been proposed in the twenties, observed for the first time in the sixties, and further investigated more recently by e.g. rocket triggered lightning. Similarly, x-rays have been detected in meter-long discharges in air at standard atmospheric conditions. Questions came up whether lightning triggered by aircraft would also generate hard radiation in-flight, its timing with respect to lightning current, its intensity and spectrum. In an earlier project, we developed a system ILDAS (http://ildas.nlr.nl) to determine the lightning current and its pattern over the aircraft with high accuracy and time-resolution. Later we added two x-ray detectors fore and aft in the aircraft.In many flights X-rays were detected indeed associated with lightning strikes. Up to now we could attribute the observed x-rays to the lightning discharge initiation, first due to leader steps in the attachment phase of the lightning channel which lasts several milliseconds, and secondly during several microseconds before the recoil current pulses. Mostly the x-rays appeared to originate from the cathode spot on the aircraft. The required fast electrons are accelerated in the high electric fields in air just before the current starts.In recent flights we observed a new phenomenon, a series of x-rays pulses lasting 8 microseconds, synchronous with the recoil current maximum of about 20 kA. From the current pattern and the relative intensity observed on both detectors, we again concluded that the x-ray originated somewhere in a region near the cathode, which was in this case the tail of the aircraft. The association with the current maximum is remarkable since an arc usually does not go with large electric fields. Arc jumps are a less likely because of the limited aircraft displacement. An alternative explanation is discharge initiation in the vicinity where the aircraft is not a part of that discharge current.In the presentation we will address such

  7. High speed optical tomography for flow visualization

    NASA Technical Reports Server (NTRS)

    Snyder, Ray; Hesselink, Lambertus

    1987-01-01

    A novel optical architecture (based on holographic optical elements) for making high speed tomographic measurements is presented. The system is designed for making density or species concentration measurements in a nonsteady fluid or combustion flow. Performance evaluations of the optical system are discussed, and a test phase object was successfully reconstructed using this optical arrangement.

  8. Maneuverability Estimation of High-Speed Craft

    DTIC Science & Technology

    2015-06-01

    derived based on equations by Lewandowski and Denny- Hubble in order to find the fundamental maneuvering characteristics. The model is developed in...characteristic of high- speed craft. A mathematical model is derived based on equations by Lewandowski and Denny- Hubble in order to find the fundamental...33 C. EQUATIONS BY DENNY AND HUBBLE ................................................43 D. NOMOTO

  9. High-Speed Sealift Technology. Volume 1

    DTIC Science & Technology

    1998-09-01

    Engineering Directorate Technology Projection Report HIGH-SPEED SEALIFT TECHNOLOGY Volume 1 BY OWEN K. RITTER MICHAEL T. TEMPLEMAN...7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Surface Warfare Center,Carderock Division,Total Ship Systems Engineering Directorate...11 3.4.3.2 Diesel Engines

  10. Laser Trigger For High Speed Camera

    NASA Astrophysics Data System (ADS)

    Chang, Rong-Seng; Lin, Chin-Wu; Cheng, Tung

    1987-09-01

    High speed camera coorperated with laser trigger to catch high speed unpredictable events has many applications: such as scoring system for the end game of missile interception, war head explosive study etc. When the event happening in a very short duration, the repetition rate of the laser ranging must be as high as 5K herze and the pulse duration should be less than 10 nsec. In some environment, like inside the aircraft, the abailable space for high speed camera to set up is limited, large film capacity camera could not be used. In order to use the small capacity film, the exact trigger time for the camera are especially important. The target velocity, camera acceleration characteristics, speed regulation, camera size, weight and the ruggedness are all be considered before the laser trigger be designed. Electric temporal gate is used to measure the time of flight ranging datum. The triangular distance measurement principle are also used to get the ranging when the base line i.e. the distance between the laser transmitter and receiver are large enough.

  11. Italian High-speed Airplane Engines

    NASA Technical Reports Server (NTRS)

    Bona, C F

    1940-01-01

    This paper presents an account of Italian high-speed engine designs. The tests were performed on the Fiat AS6 engine, and all components of that engine are discussed from cylinders to superchargers as well as the test set-up. The results of the bench tests are given along with the performance of the engines in various races.

  12. Impedance Matching for High Speed Optical Communication

    DTIC Science & Technology

    1988-06-01

    OPTICAL COMMUNICATION 16, PERaPNAL AUATHOR(S)ur. Kenry Zmuda IfTYJE OF REPORT 13b TIMý COVA5ED 14. DATE OF REPORT (Year, Month. Day) I5 PAGE COUNT EnaJ...294. 5. D. J. Nicholson and H. Zmuda, "Matching Structures for High Speed Optical Communication ", To be published in the Proceedings of Society of

  13. High-speed data word monitor

    NASA Technical Reports Server (NTRS)

    Wirth, M. N.

    1975-01-01

    Small, portable, self-contained device provides high-speed display of bit pattern or any selected portion of transmission, can suppress filler patterns so that display is not updated, and can freeze display so that specific event may be observed in detail.

  14. High-Speed Photometry of Catalina Sources

    NASA Astrophysics Data System (ADS)

    Warner, Brian; Woudt, Patrick A.

    2010-12-01

    High-speed photometry of cataclysmic variables selected from the Catalina Real-Time Transient (CRTS) survey results in orbital periods for 12 objects (10 dwarf novae and 2 polars). The period distribution for all CRTS sources has a pronounced peak near 80 minutes, confirming previous results from the Sloan Digital Sky Survey cataclysmic variables.

  15. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    1960-01-01

    Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps.

  16. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    1960-01-01

    Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps.

  17. Pulsed laser triggered high speed microfluidic switch

    NASA Astrophysics Data System (ADS)

    Wu, Ting-Hsiang; Gao, Lanyu; Chen, Yue; Wei, Kenneth; Chiou, Pei-Yu

    2008-10-01

    We report a high-speed microfluidic switch capable of achieving a switching time of 10 μs. The switching mechanism is realized by exciting dynamic vapor bubbles with focused laser pulses in a microfluidic polydimethylsiloxane (PDMS) channel. The bubble expansion deforms the elastic PDMS channel wall and squeezes the adjacent sample channel to control its fluid and particle flows as captured by the time-resolved imaging system. A switching of polystyrene microspheres in a Y-shaped channel has also been demonstrated. This ultrafast laser triggered switching mechanism has the potential to advance the sorting speed of state-of-the-art microscale fluorescence activated cell sorting devices.

  18. Some problems of high speed travel

    PubMed Central

    Reader, D. C.

    1975-01-01

    Some aspects of high speed flight are examined to investigate whether increase in speed implies any lowering of safety standards. The problem of circadian dysrhythmia is discussed and methods of attenuating its effects are explained and some new hypnotic drugs are mentioned. The risk of decompression has been quantified and predictions have been made for risks in commercial service. Cosmic radiation in supersonic aircraft is unlikely to limit commercial operation or significantly increase risks to passengers and crew. The supersonic boom is likely to limit the terrain over which supersonic aircraft can operate and regulations covering engine noise on the ground could restrict some flights. PMID:1208294

  19. High Speed SPM of Functional Materials

    SciTech Connect

    Huey, Bryan D.

    2015-08-14

    The development and optimization of applications comprising functional materials necessitates a thorough understanding of their static and dynamic properties and performance at the nanoscale. Leveraging High Speed SPM and concepts enabled by it, efficient measurements and maps with nanoscale and nanosecond temporal resolution are uniquely feasible. This includes recent enhancements for topographic, conductivity, ferroelectric, and piezoelectric properties as originally proposed, as well as newly developed methods or improvements to AFM-based mechanical, friction, thermal, and photoconductivity measurements. The results of this work reveal fundamental mechanisms of operation, and suggest new approaches for improving the ultimate speed and/or efficiency, of data storage systems, magnetic-electric sensors, and solar cells.

  20. High-speed spectroradiometer for remote sensing.

    PubMed

    Miyazaki, T; Shimizu, H; Yasuoka, Y

    1987-11-15

    A high-speed spectroradiometer designed for spectral reflectance measurement in remote sensing is described. This instrument uses a monochromatic grating and a photomultiplier system for light detection and sweeps over the 400-850-nm wavelength spectral range with the spectral resolution of 2 nm within 1 s. The instrument has the inherent advantage of portability and speed of operation which make it particularly suitable for field work in the area of fast moving surfaces, e.g., water with wave motion. Some applications of its use in laboratory and field experiments also have been presented. The instrument would seem to be an appropriate instrument for ground data collection in remote sensing.

  1. Elucidation of high-power fibre laser welding phenomena of stainless steel and effect of factors on weld geometry

    NASA Astrophysics Data System (ADS)

    Kawahito, Yousuke; Mizutani, Masami; Katayama, Seiji

    2007-10-01

    The fibre laser has been receiving great attention due to its advantages of high efficiency, high power and high beam quality, and is expected to be one of the most desirable heat sources for high-speed and deep-penetration welding. In this study, therefore, in bead-on-plate welding of Type 304 stainless steel plates with 6 kW fibre laser, the effects of laser power, power density and welding speed on the formation of sound welds were investigated with four laser beams of 130, 200, 360 and 560 µm in spot diameter, and their welding phenomena were clarified with high-speed video cameras and an x-ray transmission real-time imaging system. The weld beads showed a keyhole type of penetration at any diameter, and the maximum penetration of 11 mm in depth was obtained at 130 µm spot diameter and 0.6 m min-1 welding speed. It was found that the laser power density exerted a remarkable effect on the increase in weld penetration at higher welding speeds, and sound partially penetrated welds without welding defects such as porosity, underfilling or humping could be produced at wide process windows of welding speeds between 4.5 and 10 m min-1 with fibre laser beams of 360 µm or 560 µm in spot diameter. The high-speed video observation pictures and the x-ray images of the welding phenomena at 6 m min-1 welding speed and 360 µm spot diameter show that a sound weld bead was formed owing to a long molten pool suppressing and accommodating spattering and a stable keyhole generating no bubbles from the tip, respectively.

  2. Sensor study for high speed autonomous operations

    NASA Astrophysics Data System (ADS)

    Schneider, Anne; La Celle, Zachary; Lacaze, Alberto; Murphy, Karl; Del Giorno, Mark; Close, Ryan

    2015-06-01

    As robotic ground systems advance in capabilities and begin to fulfill new roles in both civilian and military life, the limitation of slow operational speed has become a hindrance to the wide-spread adoption of these systems. For example, military convoys are reluctant to employ autonomous vehicles when these systems slow their movement from 60 miles per hour down to 40. However, these autonomous systems must operate at these lower speeds due to the limitations of the sensors they employ. Robotic Research, with its extensive experience in ground autonomy and associated problems therein, in conjunction with CERDEC/Night Vision and Electronic Sensors Directorate (NVESD), has performed a study to specify system and detection requirements; determined how current autonomy sensors perform in various scenarios; and analyzed how sensors should be employed to increase operational speeds of ground vehicles. The sensors evaluated in this study include the state of the art in LADAR/LIDAR, Radar, Electro-Optical, and Infrared sensors, and have been analyzed at high speeds to study their effectiveness in detecting and accounting for obstacles and other perception challenges. By creating a common set of testing benchmarks, and by testing in a wide range of real-world conditions, Robotic Research has evaluated where sensors can be successfully employed today; where sensors fall short; and which technologies should be examined and developed further. This study is the first step to achieve the overarching goal of doubling ground vehicle speeds on any given terrain.

  3. Technology needs for high speed rotorcraft (2)

    NASA Technical Reports Server (NTRS)

    Scott, Mark W.

    1991-01-01

    An analytical study was conducted to identify rotorcraft concepts best capable of combining a cruise speed of 350 to 450 knots with helicopter-like low speed attributes, and to define the technology advancements needed to make them viable by the year 2000. A systematic approach was used to compare the relative attributes and mission gross weights for a wide range of concepts, resulting in a downselect to the most promising concept/mission pairs. For transport missions, tilt-wing and variable diameter tilt-rotor (VDTR) concepts were found to be superior. For a military scout/attack role, the VDTR was best, although a shrouded rotor concept could provide a highly agile, low observable alternative if its weight empty fraction could be reduced. A design speed of 375 to 425 knots was found to be the maximum desirable for transport missions, with higher speed producing rapidly diminishing benefits in productivity. The key technologies that require advancement to make the tilt-wing and VDTR concepts viable are in the areas of wing and proprotor aerodynamics, efficient structural design, flight controls, refinement of the geared flap pitch control system, expansion of the speed/descent envelope, and the structural and aerodynamic tradeoffs of wing thickness and forward sweep. For the shrouded rotor, weight reduction is essential, particularly with respect to the mechanism for covering the rotor in cruise.

  4. High speed printing with polygon scan heads

    NASA Astrophysics Data System (ADS)

    Stutz, Glenn

    2016-03-01

    To reduce and in many cases eliminate the costs associated with high volume printing of consumer and industrial products, this paper investigates and validates the use of the new generation of high speed pulse on demand (POD) lasers in concert with high speed (HS) polygon scan heads (PSH). Associated costs include consumables such as printing ink and nozzles, provisioning labor, maintenance and repair expense as well as reduction of printing lines due to high through put. Targets that are applicable and investigated include direct printing on plastics, printing on paper/cardboard as well as printing on labels. Market segments would include consumer products (CPG), medical and pharmaceutical products, universal ID (UID), and industrial products. In regards to the POD lasers employed, the wavelengths include UV(355nm), Green (532nm) and IR (1064nm) operating within the repetition range of 180 to 250 KHz.

  5. Safety issues in high speed machining

    NASA Astrophysics Data System (ADS)

    1994-05-01

    There are several risks related to High-Speed Milling, but they have not been systematically determined or studied so far. Increased loads by high centrifugal forces may result in dramatic hazards. Flying tools or fragments from a tool with high kinetic energy may damage surrounding people, machines and devices. In the project, mechanical risks were evaluated, theoretic values for kinetic energies of rotating tools were calculated, possible damages of the flying objects were determined and terms to eliminate the risks were considered. The noise levels of the High-Speed Machining center owned by the Helsinki University of Technology (HUT) and the Technical Research Center of Finland (VTT) in practical machining situation were measured and the results were compared to those after basic preventive measures were taken.

  6. High speed, high current pulsed driver circuit

    DOEpatents

    Carlen, Christopher R.

    2017-03-21

    Various technologies presented herein relate to driving a LED such that the LED emits short duration pulses of light. This is accomplished by driving the LED with short duration, high amplitude current pulses. When the LED is driven by short duration, high amplitude current pulses, the LED emits light at a greater amplitude compared to when the LED is driven by continuous wave current.

  7. Data Capture Technique for High Speed Signaling

    DOEpatents

    Barrett, Wayne Melvin; Chen, Dong; Coteus, Paul William; Gara, Alan Gene; Jackson, Rory; Kopcsay, Gerard Vincent; Nathanson, Ben Jesse; Vranas, Paylos Michael; Takken, Todd E.

    2008-08-26

    A data capture technique for high speed signaling to allow for optimal sampling of an asynchronous data stream. This technique allows for extremely high data rates and does not require that a clock be sent with the data as is done in source synchronous systems. The present invention also provides a hardware mechanism for automatically adjusting transmission delays for optimal two-bit simultaneous bi-directional (SiBiDi) signaling.

  8. High Speed Blood and Fluid Transfusion Equipment

    DTIC Science & Technology

    2010-06-01

    it stores energy for heating fluid when not attached to an external power source, (2) that it provides for high heating and infusion rates, up to...8217 % High Speed Blood and Fluid Transfusion Equipment Final Report Prepared by: Rocky Research 1598 Foothill Drive Boulder City, NV 89005...University of Nevada School of Medicine Trauma Institute Department of Surgery 2040 W. Charleston Blvd #302 Las Vegas, NV 89102 Principal

  9. Recombination phenomena in high efficiency silicon solar cells

    NASA Technical Reports Server (NTRS)

    Sah, C. T.

    1985-01-01

    The dominant recombination phenomena which limit the highest efficiency attainable in silicon solar cells under terrestrial sunlight are reviewed. The ultimate achievable efficiency is limited by the two intrinsic recombination mechanisms, the interband Auger recombination and interband Radiative recombination, both of which occur in the entire cell body but principally in the base layer. It is suggested that an optimum (26%) cell design is one with lowly doped 50 to 100 micron thick base, a perfect BSF, and zero extrinsic recombination such as the thermal mechanism at recombination centers the Shockley-Read-Hall process (SRH) in the bulk, on the surface and at the interfaces. The importance of recombination at the interfaces of a high-efficiency cell is demonstrated by the ohmic contact on the back surface whose interface recombination velocity is infinite. The importance of surface and interface recombination is demonstrated by representing the auger and radiative recombination losses by effective recombination velocities. It is demonstrated that the three highest efficiency cells may all be limited by the SRH recombination losses at recombination centers in the base layer.

  10. High-speed civil transport study

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A system study of the potential for a high-speed commercial transport has addressed technological, economic, and environmental constraints. Market projections indicate a need for fleets of transports with supersonic or greater cruise speeds by the year 2000 to 2005. The associated design requirements called for a vehicle to carry 250 to 300 passengers over a range of 5,000 to 6,000 nautical miles. The study was initially unconstrained in terms of vehicle characteristic, such as cruise speed, propulsion systems, fuels, or structural materials. Analyses led to a focus on the most promising vehicle concepts. These were concepts that used a kerosene-type fuel and cruised at Mach numbers between 2.0 to 3.2. Further systems study identified the impact of environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high-speed civil transport; significant advances are required to reduce takeoff gross weight and allow for both economic attractiveness and environmental accepatability. Specific technological requirements were identified to meet these needs.

  11. High-speed civil transport study. Summary

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A system of study of the potential for a high speed commercial transport aircraft addressed technology, economic, and environmental constraints. Market projections indicated a need for fleets of transport with supersonic or greater cruise speeds by the years 2000 to 2005. The associated design requirements called for a vehicle to carry 250 to 300 passengers over a range of 5000 to 6000 nautical miles. The study was initially unconstrained in terms of vehicle characteristics, such as cruise speed, propulsion systems, fuels, or structural materials. Analyses led to a focus on the most promising vehicle concepts. These were concepts that used a kerosene type fuel and cruised at Mach numbers between 2.0 to 3.2. Further systems study identified the impact of environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high speed civil transport. Significant advances are needed to take off gross weight and allow for both economic attractiveness and environment acceptability. Specific technological requirements were identified to meet these needs.

  12. High Speed Research Program Sonic Fatigue

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A. (Technical Monitor); Beier, Theodor H.; Heaton, Paul

    2005-01-01

    The objective of this sonic fatigue summary is to provide major findings and technical results of studies, initiated in 1994, to assess sonic fatigue behavior of structure that is being considered for the High Speed Civil Transport (HSCT). High Speed Research (HSR) program objectives in the area of sonic fatigue were to predict inlet, exhaust and boundary layer acoustic loads; measure high cycle fatigue data for materials developed during the HSR program; develop advanced sonic fatigue calculation methods to reduce required conservatism in airframe designs; develop damping techniques for sonic fatigue reduction where weight effective; develop wing and fuselage sonic fatigue design requirements; and perform sonic fatigue analyses on HSCT structural concepts to provide guidance to design teams. All goals were partially achieved, but none were completed due to the premature conclusion of the HSR program. A summary of major program findings and recommendations for continued effort are included in the report.

  13. Architectures and applications of high-speed vision

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshihiro; Oku, Hiromasa; Ishikawa, Masatoshi

    2014-11-01

    With the progress made in high-speed imaging technology, image processing systems that can process images at high frame rates, as well as their applications, are expected. In this article, we examine architectures for high-speed vision systems, and also dynamic image control, which can realize high-speed active optical systems. In addition, we also give an overview of some applications in which high-speed vision is used, including man-machine interfaces, image sensing, interactive displays, high-speed three-dimensional sensing, high-speed digital archiving, microvisual feedback, and high-speed intelligent robots.

  14. CMOS Image Sensors for High Speed Applications.

    PubMed

    El-Desouki, Munir; Deen, M Jamal; Fang, Qiyin; Liu, Louis; Tse, Frances; Armstrong, David

    2009-01-01

    Recent advances in deep submicron CMOS technologies and improved pixel designs have enabled CMOS-based imagers to surpass charge-coupled devices (CCD) imaging technology for mainstream applications. The parallel outputs that CMOS imagers can offer, in addition to complete camera-on-a-chip solutions due to being fabricated in standard CMOS technologies, result in compelling advantages in speed and system throughput. Since there is a practical limit on the minimum pixel size (4∼5 μm) due to limitations in the optics, CMOS technology scaling can allow for an increased number of transistors to be integrated into the pixel to improve both detection and signal processing. Such smart pixels truly show the potential of CMOS technology for imaging applications allowing CMOS imagers to achieve the image quality and global shuttering performance necessary to meet the demands of ultrahigh-speed applications. In this paper, a review of CMOS-based high-speed imager design is presented and the various implementations that target ultrahigh-speed imaging are described. This work also discusses the design, layout and simulation results of an ultrahigh acquisition rate CMOS active-pixel sensor imager that can take 8 frames at a rate of more than a billion frames per second (fps).

  15. Abbreviated annealing of high-speed steel

    SciTech Connect

    Zablotskii, V.K.; Bartel, G.P.

    1987-07-01

    The authors investigate the structural and phase transformations during the heating, holding, and cooling of high-speed steels of two basic groups: tungsten (R18, R12, R12F3, and R12F4K5) and tungsten-molybdenum (R6M5, 10R6M5, R6M5K5, R8M3, 10R8M3, and R8M3K6S) steels in the forged state. They propose a cooling regime with complete alpha-gamma recrystallization whose implementation at a Soviet steel plant has made it possible to reduce the duration of heat treatment and increase productivity by 20% in cutting the annealed high-speed steels.

  16. High-speed massively parallel scanning

    DOEpatents

    Decker, Derek E.

    2010-07-06

    A new technique for recording a series of images of a high-speed event (such as, but not limited to: ballistics, explosives, laser induced changes in materials, etc.) is presented. Such technique(s) makes use of a lenslet array to take image picture elements (pixels) and concentrate light from each pixel into a spot that is much smaller than the pixel. This array of spots illuminates a detector region (e.g., film, as one embodiment) which is scanned transverse to the light, creating tracks of exposed regions. Each track is a time history of the light intensity for a single pixel. By appropriately configuring the array of concentrated spots with respect to the scanning direction of the detection material, different tracks fit between pixels and sufficient lengths are possible which can be of interest in several high-speed imaging applications.

  17. Pulse Detonation Engines for High Speed Flight

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.

    2002-01-01

    Revolutionary concepts in propulsion are required in order to achieve high-speed cruise capability in the atmosphere and for low cost reliable systems for earth to orbit missions. One of the advanced concepts under study is the air-breathing pulse detonation engine. Additional work remains in order to establish the role and performance of a PDE in flight applications, either as a stand-alone device or as part of a combined cycle system. In this paper, we shall offer a few remarks on some of these remaining issues, i.e., combined cycle systems, nozzles and exhaust systems and thrust per unit frontal area limitations. Currently, an intensive experimental and numerical effort is underway in order to quantify the propulsion performance characteristics of this device. In this paper, we shall highlight our recent efforts to elucidate the propulsion potential of pulse detonation engines and their possible application to high-speed or hypersonic systems.

  18. High-speed tensile test instrument.

    PubMed

    Mott, P H; Twigg, J N; Roland, D F; Schrader, H S; Pathak, J A; Roland, C M

    2007-04-01

    A novel high-speed tensile test instrument is described, capable of measuring the mechanical response of elastomers at strain rates ranging from 10 to 1600 s(-1) for strains through failure. The device employs a drop weight that engages levers to stretch a sample on a horizontal track. To improve dynamic equilibrium, a common problem in high speed testing, equal and opposite loading was applied to each end of the sample. Demonstrative results are reported for two elastomers at strain rates to 588 s(-1) with maximum strains of 4.3. At the higher strain rates, there is a substantial inertial contribution to the measured force, an effect unaccounted for in prior works using the drop weight technique. The strain rates were essentially constant over most of the strain range and fill a three-decade gap in the data from existing methods.

  19. High speed receiver for capsule endoscope.

    PubMed

    Woo, S H; Yoon, K W; Moon, Y K; Lee, J H; Park, H J; Kim, T W; Choi, H C; Won, C H; Cho, J H

    2010-10-01

    In this study, a high-speed receiver for a capsule endoscope was proposed and implemented. The proposed receiver could receive 20 Mbps data that was sufficient to receive images with a higher resolution than conventional receivers. The receiver used a 1.2 GHz band to receive radio frequency (RF) signal, and demodulated the signal to an intermediate frequency (IF) stage (150 MHz). The demodulated signal was amplified, filtered, and under-sampled by a high-speed analog-to-digital converter (ADC). In order to decode the under-sampled data in real time, a simple frequency detection algorithm was selected and was implemented by using a FPGA. The implemented system could receive 20 Mbps data.

  20. The NASA high-speed turboprop program

    NASA Technical Reports Server (NTRS)

    Dugan, J. F.; Miller, B. A.; Graber, E. J.; Sagerser, D. A.

    1980-01-01

    Technology readiness for Mach 0.7 to 0.8 turboprop powered aircraft with the potential for fuel savings and DOC reductions of up to 30 and 15 percent respectively relative to current in-service aircraft is addressed. The areas of propeller aeroacoustics, propeller structures, turboprop installed performance, aircraft cabin environment, and turboprop engine and aircraft studies are emphasized. Large scale propeller characteristics and high speed propeller flight research tests using a modified testbed aircraft are also considered.

  1. High-speed Digital Color Imaging Pyrometry

    DTIC Science & Technology

    2011-08-01

    and environment of the events. To overcome these challenges, we have characterized and calibrated a digital high-speed color camera that may be...correction) to determine their effect on the calculated temperature. Using this technique with a Phantom color camera , we measured the temperature of...constant value of approximately 1980~K. 15. SUBJECT TERMS Pyrometry, color camera 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

  2. High Speed Crystal Growth by Q-switched Laser Melting

    NASA Technical Reports Server (NTRS)

    Cullis, A. G.

    1984-01-01

    The modification of the structural and electrical properties of semiconductors short radiation pulses obtained from Q-switched lasers is described. These modifications are accomplished by high heating and cooling rates. This processing revealed novel crystal growth and high speed resolidification phenomena. The behavior of semiconductor Si is analyzed. The annealing process typically employs short pulses of radiation in or near the visible region of the spectrum. The Q-switched ruby and Nd-YAG lasers are commonly used and these are sometimes mode locked to reduce the pulse length still further. Material to be annealed can be processed with a single large area radiation spot. Alternatively, a small radiation spot size can be used and a large sample area is covered by overlapping irradiated regions.

  3. Technology needs for high speed rotorcraft (3)

    NASA Technical Reports Server (NTRS)

    Detore, Jack; Conway, Scott

    1991-01-01

    The spectrum of vertical takeoff and landing (VTOL) type aircraft is examined to determine which aircraft are most likely to achieve high subsonic cruise speeds and have hover qualities similar to a helicopter. Two civil mission profiles are considered: a 600-n.mi. mission for a 15- and a 30-passenger payload. Applying current technology, only the 15- and 30-passenger tiltfold aircraft are capable of attaining the 450-knot design goal. The two tiltfold aircraft at 450 knots and a 30-passenger tiltrotor at 375 knots were further developed for the Task II technology analysis. A program called High-Speed Total Envelope Proprotor (HI-STEP) is recommended to meet several of these issues based on the tiltrotor concept. A program called Tiltfold System (TFS) is recommended based on the tiltrotor concept. A task is identified to resolve the best design speed from productivity and demand considerations based on the technology that emerges from the recommended programs. HI-STEP's goals are to investigate propulsive efficiency, maneuver loads, and aeroelastic stability. Programs currently in progress that may meet the other technology needs include the Integrated High Performance Turbine Engine Technology (IHPTET) (NASA Lewis) and the Advanced Structural Concepts Program funded through NASA Langley.

  4. MM-122: High speed civil transport

    NASA Technical Reports Server (NTRS)

    Demarest, Bill; Anders, Kurt; Manchec, John; Yang, Eric; Overgaard, Dan; Kalkwarf, Mike

    1992-01-01

    The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

  5. 14 CFR 25.253 - High-speed characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false High-speed characteristics. 25.253 Section...-speed characteristics. (a) Speed increase and recovery characteristics. The following speed increase and... inadvertent speed increases (including upsets in pitch and roll) must be simulated with the airplane trimmed...

  6. 14 CFR 25.253 - High-speed characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false High-speed characteristics. 25.253 Section...-speed characteristics. (a) Speed increase and recovery characteristics. The following speed increase and... inadvertent speed increases (including upsets in pitch and roll) must be simulated with the airplane trimmed...

  7. Flow Analysis By High Speed Photography And Pictures

    NASA Astrophysics Data System (ADS)

    Werle, H.

    1985-02-01

    At the ONERA hydrodynamic visualization laboratory, high-speed photography and cinematography are used for analysing flow-phenomena around fixed or mobile models in the test section of three vertical water tunnels, operating by gravity draining. These studies in water are based on the hydraulic analogy of aerodynamic incompressible flows. Flow visualization is archieved by liquid tracers (dye emissions) or gaseous tracers (fine air bubbles in suspension in water). In many cases, the pictures at normal speed or long exposure time are insufficient, for they do not permit to distinguish all the details of the phenomena, due to an averaging or motion effect. Furthermore they must be completed with high speed pictures. This is illustrated by a few visua-lization examples recently obtained on following themes - two dimensional flow around a fixed cylinder, first at the start of the flow (symmetrical vortex), then in steady regime (periodic vortex street) ; - laminar-turbulent transition in a boundary layer along a cylindrical body at zero angle of attack ; - flow separation around a sphere and wake in steady regime at small and high Reynolds numbers; - flow separation around a profile, first with fixed incidence, then with harmonic oscillations in pitch ; - core structure of a longitudinal vortex issued from a wing first organized, then disintegrated under the effect of a lengthwise pressure gradient (vortex breakdown) ; - mixing zone around a turbulent axisymmetric jet, characterized by the formation of large vortex struc-tures ; - hovering tests of an helicopter rotor, first at the start of the rotation, then in established regime, finally in cruise flight ; - case of a complete helicopter model in cruise-flight, with air-intake simulation, gas exhaust and tail rotor ; - flow around a complete delta-wing aircraft model at mean or high angle of attack, first in steady regime, then with harmonic oscillations in yaw or pitch. These results illustrate the contribution of

  8. Detailed thermodynamic analyses of high-speed compressible turbulence

    NASA Astrophysics Data System (ADS)

    Towery, Colin; Darragh, Ryan; Poludnenko, Alexei; Hamlington, Peter

    2016-11-01

    Interactions between high-speed turbulence and flames (or chemical reactions) are important in the dynamics and description of many different combustion phenomena, including autoignition and deflagration-to-detonation transition. The probability of these phenomena to occur depends on the magnitude and spectral content of turbulence fluctuations, which can impact a wide range of science and engineering problems, from the hypersonic scramjet engine to the onset of Type Ia supernovae. In this talk, we present results from new direct numerical simulations (DNS) of homogeneous isotropic turbulence with turbulence Mach numbers ranging from 0 . 05 to 1 . 0 and Taylor-scale Reynolds numbers as high as 700. A set of detailed analyses are described in both Eulerian and Lagrangian reference frames in order to assess coherent (structural) and incoherent (stochastic) thermodynamic flow features. These analyses provide direct insights into the thermodynamics of strongly compressible turbulence. Furthermore, presented results provide a non-reacting baseline for future studies of turbulence-chemistry interactions in DNS with complex chemistry mechanisms. This work was supported by the Air Force Office of Scientific Research (AFOSR) under Award No. FA9550-14-1-0273, and the Department of Defense (DoD) High Performance Computing Modernization Program (HPCMP) under a Frontier project award.

  9. High-speed neutron tomography of dynamic processes

    NASA Astrophysics Data System (ADS)

    Dierick, M.; Vlassenbroeck, J.; Masschaele, B.; Cnudde, V.; Van Hoorebeke, L.; Hillenbach, A.

    2005-04-01

    The study of fluid flow in porous media is of great importance to petrology, archeology, geology, etc. Different techniques have been developed such as visual inspection or radiography with X-rays or neutrons. The latter are particularly well suited because of the high neutron cross-section of hydrogen. This results in good contrast for water or organic fluids while being able to penetrate the bulk relatively easy. This article describes a high-speed tomography setup that enables the visualization of such phenomena in 3D instead of the classical 2D radiography. It was developed at the Ghent University (Belgium) and installed at the high-flux Neutrograph beamline at the ILL in Grenoble (France). For each tomography 100 projections of 320×240 pixels were taken at a rate of 10 frames per second, i.e. 10 s in total. This allows one to image dynamic processes that are slow compared to the measuring time. The samples studied in this experiment were mostly natural porous rocks commonly used in historical monuments. To protect these against degradation by water, much research is done on treatments with products such as consolidants and water repellents. The penetration of these products was successfully studied, as well as the resulting effects on the uptake of water. Other possible applications are transport mechanisms in soils, oil spills, wood, etc. All these are currently studied mostly in 2D. Expanding this to 3D can offer a clearer insight into these phenomena.

  10. Cryogenic, high speed, turbopump bearing cooling requirements

    NASA Technical Reports Server (NTRS)

    Dolan, Fred J.; Gibson, Howard G.; Cannon, James L.; Cody, Joe C.

    1988-01-01

    Although the Space Shuttle Main Engine (SSME) has repeatedly demonstrated the capability to perform during launch, the High Pressure Oxidizer Turbopump (HPOTP) main shaft bearings have not met their 7.5 hour life requirement. A tester is being employed to provide the capability of subjecting full scale bearings and seals to speeds, loads, propellants, temperatures, and pressures which simulate engine operating conditions. The tester design permits much more elaborate instrumentation and diagnostics than could be accommodated in an SSME turbopump. Tests were made to demonstrate the facilities; and the devices' capabilities, to verify the instruments in its operating environment and to establish a performance baseline for the flight type SSME HPOTP Turbine Bearing design. Bearing performance data from tests are being utilized to generate: (1) a high speed, cryogenic turbopump bearing computer mechanical model, and (2) a much improved, very detailed thermal model to better understand bearing internal operating conditions. Parametric tests were also made to determine the effects of speed, axial loads, coolant flow rate, and surface finish degradation on bearing performance.

  11. Pressure Distribution Over Airfoils at High Speeds

    NASA Technical Reports Server (NTRS)

    Briggs, L J; Dryden, H L

    1927-01-01

    This report deals with the pressure distribution over airfoils at high speeds, and describes an extension of an investigation of the aerodynamic characteristics of certain airfoils which was presented in NACA Technical Report no. 207. The results presented in report no. 207 have been confirmed and extended to higher speeds through a more extensive and systematic series of tests. Observations were also made of the air flow near the surface of the airfoils, and the large changes in lift coefficients were shown to be associated with a sudden breaking away of the flow from the upper surface. The tests were made on models of 1-inch chord and comparison with the earlier measurements on models of 3-inch chord shows that the sudden change in the lift coefficient is due to compressibility and not to a change in the Reynolds number. The Reynolds number still has a large effect, however, on the drag coefficient. The pressure distribution observations furnish the propeller designer with data on the load distribution at high speeds, and also give a better picture of the air-flow changes.

  12. High-speed multichannel optical switching

    SciTech Connect

    Mikaelian, A.L.; Salakhutdinov, V.K.

    1994-12-31

    The programmable interconnection between N input and N output channels based on a matrix of microholograms is considered. Such a system can be used for optical switching having high speed, about gigabits-per-second. An example of such a system using bacteriorhodopsin film is investigated both theoretically and experimentally. The thickness of bacteriorhodopsin was 50 {micro}m and the cell size 3cmx2cm. To maintain interconnects each microhologram was regenerated by means of a routing system composed of a He-Ne laser, deflectors and optical elements. Experimentally, 20 channels were used. The diameter of the microhologram was 1 mm, and the diffraction efficiency was about 2%. The tests and calculations show the possibility of arranging 10{sup 4} switching channels with speed about 1 gigabit per second.

  13. High-Speed Propeller for Aircraft

    NASA Technical Reports Server (NTRS)

    Sagerser, D. A.; Gatzen, B. S.

    1986-01-01

    Engine efficiency increased. Propeller blades required to be quite thin and highly swept to minimize compressibility losses and propeller noise during high-speed cruise. Use of 8 or 10 blades with highpropeller-power loading allows overall propeller diameter to be kept relatively small. Area-ruled spinner and integrated nacelle shape reduce compressibility losses in propeller hub region. Finally, large modern turboshaft engine and gearbox provide power to advanced propeller. Fuel savings of 30 to 50 percent over present systems anticipated. Propfan system adaptable to number of applications, such as highspeed (subsonic) business and general-aviation aircraft, and military aircraft including V/STOL.

  14. An SAE high speed ring bus overview

    NASA Astrophysics Data System (ADS)

    Kroeger, Brian W.; Shih, Hubert

    An overview of the protocols and important features of the SAE high-speed ring bus (HSRB) standard is presented here, along with the functional design of a typical ring interface unit architecture. The counterrotating ring topology, with both loopback and bypass mechanisms, provides the high degree of fault tolerance desirable in many military and avionic systems. The error-detection, fault-detection, and recovery mechanisms are briefly described to illustrate the robustness of the HSRB system. The reserved-priority token-passing protocol is shown to provide efficient and deterministic performance, uselful in real-time applications where messages must be transmitted predictably, quickly, and reliably.

  15. Conclusions from high-speed rotorcraft studies

    NASA Technical Reports Server (NTRS)

    Conway, Scott

    1991-01-01

    Under the tutelage of NASA-Ames, evaluations have been made of the technology required for high-speed rotorcraft flight with a view to the performance potential and development risks of several candidate configurations. Configurational performance limitations were associated with rotor performance at high Mach numbers and advance ratios, nacelle interference effects on rotor flow, and wing/rotor aeroelastic stability requirements. Attention is given to tiltwing, tilt-for-VTOL/fold-for-cruise rotor, and conventional tiltrotor configurations capable of carrying 30 passengers for the intercity commuter market.

  16. The World in Slow Motion: Using a High-Speed Camera in a Physics Workshop

    ERIC Educational Resources Information Center

    Dewanto, Andreas; Lim, Geok Quee; Kuang, Jianhong; Zhang, Jinfeng; Yeo, Ye

    2012-01-01

    We present a physics workshop for college students to investigate various physical phenomena using high-speed cameras. The technical specifications required, the step-by-step instructions, as well as the practical limitations of the workshop, are discussed. This workshop is also intended to be a novel way to promote physics to Generation-Y…

  17. High-speed and high-definition infrared imaging for material characterization in experimental mechanics

    NASA Astrophysics Data System (ADS)

    Gagnon, Marc-André; Marcotte, Frédérick; Lagueux, Philippe; Farley, Vincent; Guyot, Éric; Morton, Vince

    2017-05-01

    Heat transfers are involved in many phenomena such as friction, tensile stress, shear stress and material rupture. Among the challenges encountered during the characterization of such thermal patterns is the need for both high spatial and temporal resolution. Infrared imaging provides information about surface temperature that can be attributed to the stress response of the material and breaking of chemical bounds. In order to illustrate this concept, tensile and shear tests were carried out on steel, aluminum and carbon fiber composite materials and monitored using high-speed (Telops FAST-M2K) and high-definition (Telops HD-IR) infrared imaging. Results from split-Hopkinson experiments carried out on a polymer material at high strain-rate are also presented. The results illustrate how high-speed and high-definition infrared imaging in the midwave infrared (MWIR, 3 - 5 μm) spectral range can provide detailed information about the thermal properties of materials undergoing mechanical testing.

  18. High-Speed, high-power, switching transistor

    NASA Technical Reports Server (NTRS)

    Carnahan, D.; Ohu, C. K.; Hower, P. L.

    1979-01-01

    Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

  19. High-speed high-efficiency photodetectors based on heterostructures

    NASA Astrophysics Data System (ADS)

    Korolkov, V. I.

    Recent advances in the development of high-speed high-efficiency heterostructure photodetectors (HPs) are reviewed. It is noted that the performance of semiconductor photodetectors has been improved by forbidden bandwidth control. Various types of HPs are examined, including modifications of heterophotodiodes and detectors with internal amplification; avalanche photodiodes; bipolar phototransistors; and planar photoresistance devices and field-effect phototransistors. These devices are compared in terms of speed and efficiency.

  20. High-Speed, high-power, switching transistor

    NASA Technical Reports Server (NTRS)

    Carnahan, D.; Ohu, C. K.; Hower, P. L.

    1979-01-01

    Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

  1. Exhaust emissions from high speed passenger ferries

    NASA Astrophysics Data System (ADS)

    Cooper, D. A.

    Exhaust emission measurements have been carried out on-board three high-speed passenger ferries (A, B and C) during normal service routes. Ship A was powered by conventional, medium-speed, marine diesel engines, Ship B by gas turbine engines and Ship C conventional, medium-speed, marine diesel engines equipped with selective catalytic reduction (SCR) systems for NO x abatement. All ships had similar auxiliary engines (marine diesels) for generating electric power on-board. Real-world emission factors of NOx, SO2, CO, CO 2, NMVOC, CH4, N2O, NH3, PM and PAH at steady-state engine loads and for complete voyages were determined together with an estimate of annual emissions. In general, Ship B using gas turbines showed favourable NO x, PM and PAH emissions but at the expense of higher fuel consumption and CO 2 emissions. Ship C with the SCR had the lowest NO x emissions but highest NH 3 emissions especially during harbour approaches and stops. The greatest PM and PAH specific emissions were measured from auxiliary engines operating at low engine loads during harbour stops. Since all ships used a low-sulphur gas oil, SO 2 emissions were relatively low in all cases.

  2. High-speed Civil Transport Aircraft Emissions

    NASA Technical Reports Server (NTRS)

    Miake-Lye, Richard C.; Matulaitis, J. A.; Krause, F. H.; Dodds, Willard J.; Albers, Martin; Hourmouziadis, J.; Hasel, K. L.; Lohmann, R. P.; Stander, C.; Gerstle, John H.

    1992-01-01

    Estimates are given for the emissions from a proposed high speed civil transport (HSCT). This advanced technology supersonic aircraft would fly in the lower stratosphere at a speed of roughly Mach 1.6 to 3.2 (470 to 950 m/sec or 920 to 1850 knots). Because it would fly in the stratosphere at an altitude in the range of 15 to 23 km commensurate with its design speed, its exhaust effluents could perturb the chemical balance in the upper atmosphere. The first step in determining the nature and magnitude of any chemical changes in the atmosphere resulting from these proposed aircraft is to identify and quantify the chemically important species they emit. Relevant earlier work is summarized, dating back to the Climatic Impact Assessment Program of the early 1970s and current propulsion research efforts. Estimates are provided of the chemical composition of an HSCT's exhaust, and these emission indices are presented. Other aircraft emissions that are not due to combustion processes are also summarized; these emissions are found to be much smaller than the exhaust emissions. Future advances in propulsion technology, in experimental measurement techniques, and in understanding upper atmospheric chemistry may affect these estimates of the amounts of trace exhaust species or their relative importance.

  3. Simple high-speed confocal line-scanning microscope.

    PubMed

    Im, Kang-Bin; Han, Sumin; Park, Hwajoon; Kim, Dongsun; Kim, Beop-Min

    2005-06-27

    Using a line scan camera and an acousto-optic deflector (AOD), we constructed a high-speed confocal laser line-scanning microscope that can generate confocal images (512 x 512 pixels) with up to 191 frames/s without any mechanically moving parts. The line scanner consists of an AOD and a cylindrical lens, which creates a line focus sweeping over the sample. The measured resolutions in z (depth), x (perpendicular to line focus), and y (direction of line focus) directions are 3.3 mum, 0.7 mum and 0.9 mum, respectively, with a 50x objective lens. This confocal microscope may be useful for analyzing fast phenomena during biological and chemical interactions and for fast 3D image reconstruction.

  4. Optical buffer films for high-speed interferometric imaging

    NASA Astrophysics Data System (ADS)

    Lysogorski, Charles D.

    1995-02-01

    To understand wind tunnel flow-field turbulence, it is necessary to understand how high speed (kHz) transient events develop in time. The framing rates necessary to record such imagery are too high for conventional video camera systems to be used. While high-speed, film-based cameras (e.g. Cordin drum film recorders) have sufficient spatial resolution and framing rates, analyzing the data acquired with these cameras is time consuming, possibly taking days to process and digitize the film images. These limitations in existing digital imaging technologies, and pulsed flow-field illumination systems have prevented digital movies of phenomena in turbulent and unstable flow-field regions to be made with sufficient spatial and temporal resolution. To address this need, I am presenting two techniques which can record data onto an intermediate optical buffer with the desired temporal and spatial resolution. These optical buffers incorporate real-time erasable recording film which consist of a phosphor or bacteriorhodopsin (BR) that would be used to temporarily store the images which were recorded at kHz rates. These images are then reconstructed and digitized at standard video rates, and stored on an optical disk. The primary advantage of this technique is in the ability to record images at extremely fast rates (60 kHz or faster) and then digitize the images at standard video recording rates.

  5. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

  6. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

  7. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. Link to an amendment published at 76 FR 75755, December 2, 2011. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed...

  8. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

  9. Flow imaging by high speed transmission tomography.

    PubMed

    Johansen, Geir Anton; Hampel, Uwe; Hjertaker, Bjørn Tore

    2010-01-01

    Fourth generation medical X-ray scanners using a gantry with a rotating X-ray source and a fixed circular detector array as sensor head, are too slow for imaging of the process dynamics for instance in multiphase flows. To avoid inconsistent measurements and motion blurring, all measurements need to be carried out in a short time compared to the time constants of the process dynamics. Two different high speed tomographic imaging systems are presented here demonstrating that image rates of several thousand images per second is possible. Copyright 2009 Elsevier Ltd. All rights reserved.

  10. Characterization and Compensation of High Speed Digitizers

    SciTech Connect

    Fong, P; Teruya, A; Lowry, M

    2005-04-04

    Increasingly, ADC technology is being pressed into service for single single-shot instrumentation applications that were formerly served by vacuum-tube based oscilloscopes and streak cameras. ADC technology, while convenient, suffers significant performance impairments. Thus, in these demanding applications, a quantitative and accurate representation of these impairments is critical to an understanding of measurement accuracy. We have developed a phase-plane behavioral model, implemented it in SIMULINK and applied it to interleaved, high-speed ADCs (up to 4 gigasamples/sec). We have also developed and demonstrated techniques to effectively compensate for these impairments based upon the model.

  11. High Speed Solid State Circuit Breaker

    NASA Technical Reports Server (NTRS)

    Podlesak, Thomas F.

    1993-01-01

    The U.S. Army Research Laboratory, Fort Monmouth, NJ, has developed and is installing two 3.3 MW high speed solid state circuit breakers at the Army's Pulse Power Center. These circuit breakers will interrupt 4160V three phase power mains in no more than 300 microseconds, two orders of magnitude faster than conventional mechanical contact type circuit breakers. These circuit breakers utilize Gate Turnoff Thyristors (GTO's) and are currently utility type devices using air cooling in an air conditioned enclosure. Future refinements include liquid cooling, either water or two phase organic coolant, and more advanced semiconductors. Each of these refinements promises a more compact, more reliable unit.

  12. The Hubble Space Telescope high speed photometer

    NASA Technical Reports Server (NTRS)

    Vancitters, G. W., Jr.; Bless, R. C.; Dolan, J. F.; Elliot, J. L.; Robinson, E. L.; White, R. L.

    1988-01-01

    The Hubble Space Telescope will provide the opportunity to perform precise astronomical photometry above the disturbing effects of the atmosphere. The High Speed Photometer is designed to provide the observatory with a stable, precise photometer with wide dynamic range, broad wavelenth coverage, time resolution in the microsecond region, and polarimetric capability. Here, the scientific requirements for the instrument are examined, the unique design features of the photometer are explored, and the improvements to be expected over the performance of ground-based instruments are projected.

  13. Finite element methods for high speed flows

    NASA Technical Reports Server (NTRS)

    Loehner, R.; Morgan, K.; Peraire, J.; Zienkiewicz, O. C.

    1985-01-01

    An explicit finite element based solution procedure for solving the equations of compressible viscous high speed flow is presented. The method uses domain splitting to advance the solution with different timesteps on different portions of the mesh. For steady inviscid flows, adaptive mesh refinement procedures are successfully employed to enhance the definition of discontinuities. Preliminary ideas on the application of adaptive mesh refinement to the solution of problems involving steady viscous flow are presented. Sample timings are given for the performance of the finite element code on modern supercomputers.

  14. Continuous QKD and high speed data encryption

    NASA Astrophysics Data System (ADS)

    Zbinden, Hugo; Walenta, Nino; Guinnard, Olivier; Houlmann, Raphael; Wen, Charles Lim Ci; Korzh, Boris; Lunghi, Tommaso; Gisin, Nicolas; Burg, Andreas; Constantin, Jeremy; Legré, Matthieu; Trinkler, Patrick; Caselunghe, Dario; Kulesza, Natalia; Trolliet, Gregory; Vannel, Fabien; Junod, Pascal; Auberson, Olivier; Graf, Yoan; Curchod, Gilles; Habegger, Gilles; Messerli, Etienne; Portmann, Christopher; Henzen, Luca; Keller, Christoph; Pendl, Christian; Mühlberghuber, Michael; Roth, Christoph; Felber, Norbert; Gürkaynak, Frank; Schöni, Daniel; Muheim, Beat

    2013-10-01

    We present the results of a Swiss project dedicated to the development of high speed quantum key distribution and data encryption. The QKD engine features fully automated key exchange, hardware key distillation based on finite key security analysis, efficient authentication and wavelength division multiplexing of the quantum and the classical channel and one-time pas encryption. The encryption device allows authenticated symmetric key encryption (e.g AES) at rates of up to 100 Gb/s. A new quantum key can uploaded up to 1000 times second from the QKD engine.

  15. High-speed multispectral confocal biomedical imaging

    PubMed Central

    Carver, Gary E.; Locknar, Sarah A.; Morrison, William A.; Krishnan Ramanujan, V.; Farkas, Daniel L.

    2014-01-01

    Abstract. A new approach for generating high-speed multispectral confocal images has been developed. The central concept is that spectra can be acquired for each pixel in a confocal spatial scan by using a fast spectrometer based on optical fiber delay lines. This approach merges fast spectroscopy with standard spatial scanning to create datacubes in real time. The spectrometer is based on a serial array of reflecting spectral elements, delay lines between these elements, and a single element detector. The spatial, spectral, and temporal resolution of the instrument is described and illustrated by multispectral images of laser-induced autofluorescence in biological tissues. PMID:24658777

  16. Novel collective phenomena in high-energy proton-proton and proton-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Dusling, Kevin; Li, Wei; Schenke, Björn

    2016-01-01

    The observation of long-range rapidity correlations among particles in high-multiplicity p-p and p-Pb collisions has created new opportunities for investigating novel high-density QCD phenomena in small colliding systems. We review experimental results related to the study of collective phenomena in small systems at RHIC and the LHC along with the related developments in theory and phenomenology. Perspectives on possible future directions for research are discussed with the aim of exploring emergent QCD phenomena.

  17. Protective Effectiveness of Porous Shields Under the Influence of High-Speed Impact Loading

    NASA Astrophysics Data System (ADS)

    Kramshonkov, E. N.; Krainov, A. V.; Shorohov, P. V.

    2016-02-01

    The results of numerical simulations of a compact steel impactor with the aluminum porous shields under high-speed shock loading are presented. The porosity of barrier varies in wide range provided that its mass stays the same, but the impactor has always equal (identical) mass. Here presented the final assessment of the barrier perforation speed depending on its porosity and initial shock speed. The range of initial impact speed varies from 1 to 10 km/s. Physical phenomena such as: destruction, melting, vaporization of a interacting objects are taken into account. The analysis of a shield porosity estimation disclosed that the protection effectiveness of porous shield reveals at the initial impact speed grater then 1.5 km/s, and it increases when initial impact speed growth.

  18. Study of high-speed civil transports

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A systems study to identify the economic potential for a high-speed commercial transport (HSCT) has considered technology, market characteristics, airport infrastructure, and environmental issues. Market forecasts indicate a need for HSCT service in the 2000/2010 time frame conditioned on economic viability and environmental acceptability. Design requirements focused on a 300 passenger, 3 class service, and 6500 nautical mile range based on the accelerated growth of the Pacific region. Compatibility with existing airports was an assumed requirement. Mach numbers between 2 and 25 were examined in conjunction with the appropriate propulsion systems, fuels, structural materials, and thermal management systems. Aircraft productivity was a key parameter with aircraft worth, in comparison to aircraft price, being the airline-oriented figure of merit. Aircraft screening led to determination that Mach 3.2 (TSJF) would have superior characteristics to Mach 5.0 (LNG) and the recommendation that the next generation high-speed commercial transport aircraft use a kerosene fuel. The sensitivity of aircraft performance and economics to environmental constraints (e.g., sonic boom, engine emissions, and airport/community noise) was identified together with key technologies. In all, current technology is not adequate to produce viable HSCTs for the world marketplace. Technology advancements must be accomplished to meet environmental requirements (these requirements are as yet undetermined for sonic boom and engine emissions). High priority is assigned to aircraft gross weight reduction which benefits both economics and environmental aspects. Specific technology requirements are identified and national economic benefits are projected.

  19. Applications for high-speed infrared imaging

    NASA Astrophysics Data System (ADS)

    Richards, Austin A.

    2005-03-01

    The phrase high-speed imaging is generally associated with short exposure times, fast frame rates or both. Supersonic projectiles, for example, are often impossible to see with the unaided eye, and require strobe photography to stop their apparent motion. It is often necessary to image high-speed objects in the infrared region of the spectrum, either to detect them or to measure their surface temperature. Conventional infrared cameras have time constants similar to the human eye, so they too, are often at a loss when it comes to photographing fast-moving hot targets. Other types of targets or scenes such as explosions change very rapidly with time. Visualizing those changes requires an extremely high frame rate combined with short exposure times in order to slow down a dynamic event so that it can be studied and quantified. Recent advances in infrared sensor technology and computing power have pushed the envelope of what is possible to achieve with commercial IR camera systems.

  20. TOPICAL REVIEW: Plasmas in high speed aerodynamics

    NASA Astrophysics Data System (ADS)

    Bletzinger, P.; Ganguly, B. N.; Van Wie, D.; Garscadden, A.

    2005-02-01

    A review is presented of the studies in the former Soviet Union and in the USA of the mutual interactions of plasmas and high speed flows and shocks. There are reports from as early as the 1980s of large changes in the standoff distance ahead of a blunt body in ballistic tunnels, significantly reduced drag and modifications of travelling shocks in bounded weakly ionized gases. Energy addition to the flow results in an increase in the local sound speed that leads to expected modifications of the flow and changes to the pressure distribution around a vehicle due to the decrease in local Mach number. The critical question was, did a plasma provide a significant energy multiplier for the system? There have been a large number of experimental studies on the influence of a weakly ionized plasma on relatively low Mach number shocks and inherently also on the influence of the shock on the plasma. This literature is reviewed and illustrated with representative examples. The convergence through more controlled experiments and improved modelling to a physics understanding of the effects being essentially due to heating is outlined. It is demonstrated that the heating in many cases is global; however, tailored experiments with positive columns, dielectric barrier discharges and focused microwave plasmas can produce very localized heating. The latter appears more attractive for energy efficiency in flow control. Tailored localized ionization and thermal effects are also of interest for high speed inlet shock control and for producing reliable ignition for short residence time combustors, and work in these areas is also reviewed.

  1. Quantitative Image Analysis Techniques with High-Speed Schlieren Photography

    NASA Technical Reports Server (NTRS)

    Pollard, Victoria J.; Herron, Andrew J.

    2017-01-01

    Optical flow visualization techniques such as schlieren and shadowgraph photography are essential to understanding fluid flow when interpreting acquired wind tunnel test data. Output of the standard implementations of these visualization techniques in test facilities are often limited only to qualitative interpretation of the resulting images. Although various quantitative optical techniques have been developed, these techniques often require special equipment or are focused on obtaining very precise and accurate data about the visualized flow. These systems are not practical in small, production wind tunnel test facilities. However, high-speed photography capability has become a common upgrade to many test facilities in order to better capture images of unsteady flow phenomena such as oscillating shocks and flow separation. This paper describes novel techniques utilized by the authors to analyze captured high-speed schlieren and shadowgraph imagery from wind tunnel testing for quantification of observed unsteady flow frequency content. Such techniques have applications in parametric geometry studies and in small facilities where more specialized equipment may not be available.

  2. Surface and Bulk Carbide Transformations in High-Speed Steel

    NASA Astrophysics Data System (ADS)

    Godec, M.; Večko Pirtovšek, T.; Šetina Batič, B.; McGuiness, P.; Burja, J.; Podgornik, B.

    2015-11-01

    We have studied the transformation of carbides in AISI M42 high-speed steels in the temperature window used for forging. The annealing was found to result in the partial transformation of the large, metastable M2C carbides into small, more stable grains of M6C, with an associated change in the crystal orientation. In addition, MC carbides form during the transformation of M2C to M6C. From the high-speed-steel production point of view, it is beneficial to have large, metastable carbides in the cast structure, which later during annealing, before the forging, transform into a structure of polycrystalline carbides. Such carbides can be easily decomposed into several small carbides, which are then randomly distributed in the microstructure. The results also show an interesting difference in the carbide-transformation reactions on the surface versus the bulk of the alloy, which has implications for in-situ studies of bulk phenomena that are based on surface observations.

  3. Surface and Bulk Carbide Transformations in High-Speed Steel.

    PubMed

    Godec, M; Večko Pirtovšek, T; Šetina Batič, B; McGuiness, P; Burja, J; Podgornik, B

    2015-11-05

    We have studied the transformation of carbides in AISI M42 high-speed steels in the temperature window used for forging. The annealing was found to result in the partial transformation of the large, metastable M2C carbides into small, more stable grains of M6C, with an associated change in the crystal orientation. In addition, MC carbides form during the transformation of M2C to M6C. From the high-speed-steel production point of view, it is beneficial to have large, metastable carbides in the cast structure, which later during annealing, before the forging, transform into a structure of polycrystalline carbides. Such carbides can be easily decomposed into several small carbides, which are then randomly distributed in the microstructure. The results also show an interesting difference in the carbide-transformation reactions on the surface versus the bulk of the alloy, which has implications for in-situ studies of bulk phenomena that are based on surface observations.

  4. Surface and Bulk Carbide Transformations in High-Speed Steel

    PubMed Central

    Godec, M.; Večko Pirtovšek, T.; Šetina Batič, B.; McGuiness, P.; Burja, J.; Podgornik, B.

    2015-01-01

    We have studied the transformation of carbides in AISI M42 high-speed steels in the temperature window used for forging. The annealing was found to result in the partial transformation of the large, metastable M2C carbides into small, more stable grains of M6C, with an associated change in the crystal orientation. In addition, MC carbides form during the transformation of M2C to M6C. From the high-speed-steel production point of view, it is beneficial to have large, metastable carbides in the cast structure, which later during annealing, before the forging, transform into a structure of polycrystalline carbides. Such carbides can be easily decomposed into several small carbides, which are then randomly distributed in the microstructure. The results also show an interesting difference in the carbide-transformation reactions on the surface versus the bulk of the alloy, which has implications for in-situ studies of bulk phenomena that are based on surface observations. PMID:26537780

  5. Nanopatterned Quantum Dot Lasers for High Speed, High Efficiency, Operation

    DTIC Science & Technology

    2015-04-27

    SECURITY CLASSIFICATION OF: Quantum dot (QD) active regions hold potential for realizing extremely high performance semiconductor diode lasers...2009 31-Dec-2014 Approved for Public Release; Distribution Unlimited Final Report: Nanopatterned Quantum Dot Lasers for High Speed, High Efficiency...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 quantum dots , nanopatterning, MOCVD, laser REPORT DOCUMENTATION PAGE 11

  6. ACTS High-Speed VSAT Demonstrated

    NASA Technical Reports Server (NTRS)

    Tran, Quang K.

    1999-01-01

    The Advanced Communication Technology Satellite (ACTS) developed by NASA has demonstrated the breakthrough technologies of Ka-band transmission, spot-beam antennas, and onboard processing. These technologies have enabled the development of very small and ultrasmall aperture terminals (VSAT s and USAT's), which have capabilities greater than have been possible with conventional satellite technologies. The ACTS High Speed VSAT (HS VSAT) is an effort at the NASA Glenn Research Center at Lewis Field to experimentally demonstrate the maximum user throughput data rate that can be achieved using the technologies developed and implemented on ACTS. This was done by operating the system uplinks as frequency division multiple access (FDMA), essentially assigning all available time division multiple access (TDMA) time slots to a single user on each of two uplink frequencies. Preliminary results show that, using a 1.2-m antenna in this mode, the High Speed VSAT can achieve between 22 and 24 Mbps of the 27.5 Mbps burst rate, for a throughput efficiency of 80 to 88 percent.

  7. High-speed optogenetic circuit mapping

    NASA Astrophysics Data System (ADS)

    Augustine, George J.; Chen, Susu; Gill, Harin; Katarya, Malvika; Kim, Jinsook; Kudolo, John; Lee, Li M.; Lee, Hyunjeong; Lo, Shun Qiang; Nakajima, Ryuichi; Park, Min-Yoon; Tan, Gregory; Tang, Yanxia; Teo, Peggy; Tsuda, Sachiko; Wen, Lei; Yoon, Su-In

    2013-03-01

    Scanning small spots of laser light allows mapping of synaptic circuits in brain slices from transgenic mice expressing channelrhodopsin-2 (ChR2). These light spots photostimulate presynaptic neurons expressing ChR2, while postsynaptic responses can be monitored in neurons that do not express ChR2. Correlating the location of the light spot with the amplitude of the postsynaptic response elicited at that location yields maps of the spatial organization of the synaptic circuits. This approach yields maps within minutes, which is several orders of magnitude faster than can be achieved with conventional paired electrophysiological methods. We have applied this high-speed technique to map local circuits in many brain regions. In cerebral cortex, we observed that maps of excitatory inputs to pyramidal cells were qualitatively different from those measured for interneurons within the same layers of the cortex. In cerebellum, we have used this approach to quantify the convergence of molecular layer interneurons on to Purkinje cells. The number of converging interneurons is reduced by treatment with gap junction blockers, indicating that electrical synapses between interneurons contribute substantially to the spatial convergence. Remarkably, gap junction blockers affect convergence in sagittal cerebellar slices but not in coronal slices, indicating sagittal polarization of electrical coupling between interneurons. By measuring limb movement or other forms of behavioral output, this approach also can be used in vivo to map brain circuits non-invasively. In summary, ChR2-mediated high-speed mapping promises to revolutionize our understanding of brain circuitry.

  8. High-Speed Photography and Digital Optical Measurement Techniques for Geomaterials: Fundamentals and Applications

    NASA Astrophysics Data System (ADS)

    Xing, H. Z.; Zhang, Q. B.; Braithwaite, C. H.; Pan, B.; Zhao, J.

    2017-06-01

    Geomaterials (i.e. rock, sand, soil and concrete) are increasingly being encountered and used in extreme environments, in terms of the pressure magnitude and the loading rate. Advancing the understanding of the mechanical response of materials to impact loading relies heavily on having suitable high-speed diagnostics. One such diagnostic is high-speed photography, which combined with a variety of digital optical measurement techniques can provide detailed insights into phenomena including fracture, impact, fragmentation and penetration in geological materials. This review begins with a brief history of high-speed imaging. Section 2 discusses of the current state of the art of high-speed cameras, which includes a comparison between charge-coupled device and complementary metal-oxide semiconductor sensors. The application of high-speed photography to geomechanical experiments is summarized in Sect. 3. Section 4 is concerned with digital optical measurement techniques including photoelastic coating, Moiré, caustics, holographic interferometry, particle image velocimetry, digital image correlation and infrared thermography, in combination with high-speed photography to capture transient phenomena. The last section provides a brief summary and discussion of future directions in the field.

  9. Driver speed selection on high-speed two-lane highways: Comparing speed profiles between uniform and differential speed limits.

    PubMed

    Russo, Brendan J; Savolainen, Peter T; Gates, Timothy J; Kay, Jonathan J; Frazier, Sterling

    2017-07-04

    Although a considerable amount of prior research has investigated the impacts of speed limits on traffic safety and operations, much of this research, and nearly all of the research related to differential speed limits, has been specific to limited access freeways. The unique safety and operational issues on highways without access control create difficulty relating the conclusions from prior freeway-related speed limit research to 2-lane highways, particularly research on differential limits due to passing limitations and subsequent queuing. Therefore, the objective of this study was to assess differences in driver speed selection with respect to the posted speed limit on rural 2-lane highways, with a particular emphasis on the differences between uniform and differential speed limits. Data were collected from nearly 59,000 vehicles across 320 sites in Montana and 4 neighboring states. Differences in mean speeds, 85th percentile speeds, and the standard deviation in speeds for free-flowing vehicles were examined across these sites using ordinary least squares regression models. Ultimately, the results of the analysis show that the mean speed, 85th percentile speed, and variability in travel speeds for free-flowing vehicles on 2-lane highways are generally lower at locations with uniform 65 mph speed limits, compared to locations with differential limits of 70 mph for cars and 60 mph for trucks. In addition to posted speed limits, several site characteristics were shown to influence speed selection including shoulder widths, frequency of horizontal curves, percentage of the segment that included no passing zones, and hourly volumes. Differences in vehicle speed characteristics were also observed between states, indicating that speed selection may also be influenced by local factors, such as driver population or enforcement.

  10. High-speed spatial scanning pyrometer

    NASA Technical Reports Server (NTRS)

    Cezairliyan, A.; Chang, R. F.; Foley, G. M.; Miller, A. P.

    1993-01-01

    A high-speed spatial scanning pyrometer has been designed and developed to measure spectral radiance temperatures at multiple target points along the length of a rapidly heating/cooling specimen in dynamic thermophysical experiments at high temperatures (above about 1800 K). The design, which is based on a self-scanning linear silicon array containing 1024 elements, enables the pyrometer to measure spectral radiance temperatures (nominally at 650 nm) at 1024 equally spaced points along a 25-mm target length. The elements of the array are sampled consecutively every 1 microsec, thereby permitting one cycle of measurements to be completed in approximately 1 msec. Procedures for calibration and temperature measurement as well as the characteristics and performance of the pyrometer are described. The details of sources and estimated magnitudes of possible errors are given. An example of measurements of radiance temperatures along the length of a tungsten rod, during its cooling following rapid resistive pulse heating, is presented.

  11. Very high-speed digital holography

    NASA Astrophysics Data System (ADS)

    Pérez López, Carlos; Mendoza Santoyo, Fernando; Rodríguez Vera, Ramón; Moreno, David; Barrientos, Bernardino

    2006-08-01

    It is reported for the first time the use of a high speed camera in digital holography with an out of plane sensitivity. The camera takes the image plane holograms of a cw laser illuminated rectangular framed polyester material at a rate of 5000 per second, that is a spacing of 200 microseconds between holograms, and 512 by 500 pixels at 10 bit resolution. The freely standing object has a random movement due to non controlled environmental air currents. As is usual with this technique each digital hologram is Fourier processed in order to obtain upon comparison with a consecutive digital hologram the phase map of the displacement. High quality results showing the amplitude and direction of the random movement are presented.

  12. Interpolation circuit with high resolution and high response speed

    NASA Astrophysics Data System (ADS)

    Piao, Weiying; Yuan, Yibao; Xu, Lianhu; Zhang, Hao

    2009-05-01

    An interpolation circuit based upon the looking-up table by hardware is presented. Output data of two A/D convertors are connected to ROM's address bus. The memory space of ROM is divided. When the address bus is activated by A/D conversion's output data, the ROM's output data is interpolation data. This circuit has high response speed, and it is easy to obtain high interpolation multiple. The same kind of hardware circuit can achieve different interpolation multiple by modifying ROM's data. It is very convenient and flexible. The principle of direction judgment and counting is analyzed; the implementation speed and maximal interpolation multiple are discussed in this paper. Finally through experiment, make sure this circuit not only has the characteristic of high response speed and high interpolation multiple, but also avoids the counting error of micro-computer interpolation.

  13. High-speed ACR/NEMA interface

    NASA Astrophysics Data System (ADS)

    Reijns, Gerard L.; Santilli, D.; Schellingerhout, G.; Jochem, A. J.; Ottes, Fenno P.; van Aken, I. W.

    1990-08-01

    The design and implementation of a standard high speed ACR-NEMA communications interface is described. The upper layers e.g. the Presentation layer, Session layer and part of the Transport/Network layer have been implemented in software. In order to reach the speed requirement of 8M byte/sec. the lower layers e.g. part of the Transport/Network layer and Data Link layer have been implemented in hardware. We have developed and built an interface for an IBM personal computer P5/2 model 50, working under the operating system OS/2. The PS/2, model 50 has been equipped with a fast micro-channel bus, which enables a large throughput. The operating systern OS/2 has a multitasking capability, which enables concurrent programming. In order to minimize the delays, we used this multitasking facility to create a number of parallel operating "threads". The Transport/Network layer functions have been implemented using a receive thread, two send threads and a device driver with three hardware registers. The time to transfer a packet by DMA, to initiate the DMA logic and to execute the required Kernal functions have each been measured and figures are shown. The Data Link layer provides for storage of two packets in two separate random access memories (RAM's). These two RAM's enable a pipelined operation, which minimizes the delay in the Data Link layer.

  14. High Speed Fibre Optic Backbone LAN

    NASA Astrophysics Data System (ADS)

    Tanimoto, Masaaki; Hara, Shingo; Kajita, Yuji; Kashu, Fumitoshi; Ikeuchi, Masaru; Hagihara, Satoshi; Tsuzuki, Shinji

    1987-09-01

    Our firm has developed the SUMINET-4100 series, a fibre optic local area network (LAN), to serve the communications system trunk line needs for facilities, such as steel refineries, automobile plants and university campuses, that require large transmission capacity, and for the backbone networks used in intelligent building systems. The SUMINET-4100 series is already in service in various fields of application. Of the networks available in this series, the SUMINET-4150 has a trunk line speed of 128 Mbps and the multiplexer used for time division multiplexing (TDM) was enabled by designing an ECL-TTL gate array (3000 gates) based custom LSI. The synchronous, full-duplex V.24 and V.3.5 interfaces (SUMINET-2100) are provided for use with general purpose lines. And the IBM token ring network, the SUMINET-3200, designed for heterogeneous PCs and the Ethernet can all be connected to sub loops. Further, the IBM 3270 TCA and 5080 CADAM can be connected in the local mode. Interfaces are also provided for the NTT high-speed digital service, the digital PBX systems, and the Video CODEC system. The built-in loop monitor (LM) and network supervisory processor (NSP) provide management of loop utilization and send loop status signals to the host CPU's network configuration and control facility (NCCF). These built-in functions allow both the computer system and LAN to be managed from a single source at the host. This paper outlines features of the SUMINET-4150 and provides an example of its installation.

  15. High-speed cameras at Los Alamos

    NASA Astrophysics Data System (ADS)

    Brixner, Berlyn

    1997-05-01

    In 1943, there was no camera with the microsecond resolution needed for research in Atomic Bomb development. We had the Mitchell camera (100 fps), the Fastax (10 000), the Marley (100 000), the drum streak (moving slit image) 10-5 s resolution, and electro-optical shutters for 10-6 s. Julian Mack invented a rotating-mirror camera for 10-7 s, which was in use by 1944. Small rotating mirror changes secured a resolution of 10-8 s. Photography of oscilloscope traces soon recorded 10-6 resolution, which was later improved to 10-8 s. Mack also invented two time resolving spectrographs for studying the radiation of the first atomic explosion. Much later, he made a large aperture spectrograph for shock wave spectra. An image dissecting drum camera running at 107 frames per second (fps) was used for studying high velocity jets. Brixner invented a simple streak camera which gave 10-8 s resolution. Using a moving film camera, an interferometer pressure gauge was developed for measuring shock-front pressures up to 100 000 psi. An existing Bowen 76-lens frame camera was speeded up by our turbine driven mirror to make 1 500 000 fps. Several streak cameras were made with writing arms from 4 1/2 to 40 in. and apertures from f/2.5 to f/20. We made framing cameras with top speeds of 50 000, 1 000 000, 3 500 000, and 14 000 000 fps.

  16. High-Speed RaPToRS

    NASA Astrophysics Data System (ADS)

    Henchen, Robert; Esham, Benjamin; Becker, William; Pogozelski, Edward; Padalino, Stephen; Sangster, Thomas; Glebov, Vladimir

    2008-11-01

    The High-Speed Rapid Pneumatic Transport of Radioactive Samples (HS-RaPToRS) system, designed to quickly and safely move radioactive materials, was assembled and tested at the Mercury facility of the Naval Research Laboratory (NRL) in Washington D.C. A sample, which is placed inside a four-inch-diameter carrier, is activated before being transported through a PVC tube via airflow. The carrier travels from the reaction chamber to the end station where it pneumatically brakes prior to the gate. A magnetic latch releases the gate when the carrier arrives and comes to rest. The airflow, optical carrier-monitoring devices, and end gate are controlled manually or automatically with LabView software. The installation and testing of the RaPToRS system at NRL was successfully completed with transport times of less than 3 seconds. The speed of the carrier averaged 16 m/s. Prospective facilities for similar systems include the Laboratory for Laser Energetics and the National Ignition Facility.

  17. Using a High-Speed Camera to Measure the Speed of Sound

    ERIC Educational Resources Information Center

    Hack, William Nathan; Baird, William H.

    2012-01-01

    The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

  18. Using a High-Speed Camera to Measure the Speed of Sound

    ERIC Educational Resources Information Center

    Hack, William Nathan; Baird, William H.

    2012-01-01

    The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

  19. High speed operation of permanent magnet machines

    NASA Astrophysics Data System (ADS)

    El-Refaie, Ayman M.

    This work proposes methods to extend the high-speed operating capabilities of both the interior PM (IPM) and surface PM (SPM) machines. For interior PM machines, this research has developed and presented the first thorough analysis of how a new bi-state magnetic material can be usefully applied to the design of IPM machines. Key elements of this contribution include identifying how the unique properties of the bi-state magnetic material can be applied most effectively in the rotor design of an IPM machine by "unmagnetizing" the magnet cavity center posts rather than the outer bridges. The importance of elevated rotor speed in making the best use of the bi-state magnetic material while recognizing its limitations has been identified. For surface PM machines, this research has provided, for the first time, a clear explanation of how fractional-slot concentrated windings can be applied to SPM machines in order to achieve the necessary conditions for optimal flux weakening. A closed-form analytical procedure for analyzing SPM machines designed with concentrated windings has been developed. Guidelines for designing SPM machines using concentrated windings in order to achieve optimum flux weakening are provided. Analytical and numerical finite element analysis (FEA) results have provided promising evidence of the scalability of the concentrated winding technique with respect to the number of poles, machine aspect ratio, and output power rating. Useful comparisons between the predicted performance characteristics of SPM machines equipped with concentrated windings and both SPM and IPM machines designed with distributed windings are included. Analytical techniques have been used to evaluate the impact of the high pole number on various converter performance metrics. Both analytical techniques and FEA have been used for evaluating the eddy-current losses in the surface magnets due to the stator winding subharmonics. Techniques for reducing these losses have been

  20. Development and Fielding of High-Speed Laser Shadowgraphy for Electro-Magnetically Driven Cylindrical Implosions

    DTIC Science & Technology

    2013-06-01

    shockwave in a cylindrical geometry provides fundamental benchmarks used in the modeling of 1-D and 2-D hydrodynamic phenomena from high or solid...DEVELOPMENT AND FIELDING OF HIGH-SPEED LASER SHADOWGRAPHY FOR ELECTRO -MAGNETICALLY DRIVEN CYLINDRICAL IMPLOSIONS J. P. Roberts, G. Rodriguez...an electro -magnetically driven solid density liner implosion in Lucite is described. The laser shadowgraphy system utilizes an advanced high-energy

  1. Combustion in High Speed Air Flows.

    DTIC Science & Technology

    1982-05-01

    objective is the analysis of reacting multiphase flows in advanced air-breathing propulsion systems. This work involves the formulation and evaluation...of new theoretical descriptions of multiphase turbulent mixing and chemical kinetic phenomena in subsonic and supersonic air flows , and the gen...area involves the development of analyti- cal models of the phenomena occurring in the multiphase turbulent reacting flows involved in spray flame

  2. Neutron and high speed photogrammetric arcjet diagnosis

    NASA Technical Reports Server (NTRS)

    Stewart, P. A. E.; Rogers, J. D.; Fowler, P. H.; Deininger, W. D.; Taylor, A. D.

    1989-01-01

    Two methods for real time internal diagnostics of arcjet engines are described. One method uses cold, thermal, or epithermal neutrons. Cold neutrons are used to detect the presence and location of hydrogenous propellants. Thermal neutrons are used to delineate the edge contours of anode and cathode surfaces and to measure stress/strain. Epithermal neutrons are used to measure temperatures on arcjet surfaces, bulk material temperatures, and point temperatures in bulk materials. It is found that this method, with an exposure time of 10 min, produces at temperature accuracy for W or Re of + or - 2.5 C. The other method uses visible-light high-speed photogrammetry to obtain images of the transient behavior of the arc during start-up and to relate this behavior to electrial supply characteristics such as voltage, current, and ripple.

  3. High Speed Photography In The United Kingdom

    NASA Astrophysics Data System (ADS)

    Lunn, George H.

    1989-06-01

    At the 13th Congress in Tokyo, I presented a paper with this title in which some early history was mentioned followed by a more detailed study of the activities of the main research groups in Britain from the period between 1950 and 1978. On this occasion, some early topics will be mentioned. The period since 1978 has seen quite a few changes in that research is now more in the hands of commercial groups as opposed to the previous governmental laboratories. It is true that the pricipal camera systems have reached towards their physical limits. However other new techniques are still expanding, for example, Lasers, Holography and Videography. The new systems are principally in the hands of major or specialist companies with the offical and industrial research groups using their products. The Association for High Speed Photography continues to encourage both researchers and users by providing oportunities for users, suppliers and manufacturers to meet and discuss.

  4. Design of a high speed business transport

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The design of a High Speed Business Transport (HSBT) was considered by the Aeronautical Design Class during the academic year 1989 to 1990. The project was chosen to offer an opportunity to develop user friendliness for some computer codes such as WAVE DRAG, supplied by NASA/Langley, and to experiment with several design lessons developed by Dr. John McMasters and his colleages at Boeing. Central to these design lessons was an appeal to marketing and feasibility considerations. There was an emphasis upon simplified analytical techniques to study trades and to stimulate creative thinking before committing to extensive analytical activity. Two designs stood out among all the rest because of the depth of thought and consideration of alternatives. One design, the Aurora, used a fixed wing design to satisfy the design mission: the Viero used a swept wing configuration to overcome problems related to supersonic flight. A summary of each of these two designs is given.

  5. High speed civil transport aerodynamic optimization

    NASA Technical Reports Server (NTRS)

    Ryan, James S.

    1994-01-01

    This is a report of work in support of the Computational Aerosciences (CAS) element of the Federal HPCC program. Specifically, CFD and aerodynamic optimization are being performed on parallel computers. The long-range goal of this work is to facilitate teraflops-rate multidisciplinary optimization of aerospace vehicles. This year's work is targeted for application to the High Speed Civil Transport (HSCT), one of four CAS grand challenges identified in the HPCC FY 1995 Blue Book. This vehicle is to be a passenger aircraft, with the promise of cutting overseas flight time by more than half. To meet fuel economy, operational costs, environmental impact, noise production, and range requirements, improved design tools are required, and these tools must eventually integrate optimization, external aerodynamics, propulsion, structures, heat transfer, controls, and perhaps other disciplines. The fundamental goal of this project is to contribute to improved design tools for U.S. industry, and thus to the nation's economic competitiveness.

  6. Technology needs for high-speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Rutherford, John; Orourke, Matthew; Martin, Christopher; Lovenguth, Marc; Mitchell, Clark

    1991-01-01

    A study to determine the technology development required for high-speed rotorcraft development was conducted. The study begins with an initial assessment of six concepts capable of flight at, or greater than 450 knots with helicopter-like hover efficiency (disk loading less than 50 pfs). These concepts were sized and evaluated based on measures of effectiveness and operational considerations. Additionally, an initial assessment of the impact of technology advances on the vehicles attributes was made. From these initial concepts a tilt wing and rotor/wing concepts were selected for further evaluation. A more detailed examination of conversion and technology trade studies were conducted on these two vehicles, each sized for a different mission.

  7. High-speed electrical motor evaluation

    SciTech Connect

    Not Available

    1989-02-03

    Under this task, MTI conducted a general review of state-of-the-art high-speed motors. The purpose of this review was to assess the operating parameters, limitations and performance of existing motor designs, and to establish commercial sources for a motor compatible with the requirements of the Brayton-cycle system. After the motor requirements were established, a list of motor types, manufacturers and designs capable of achieving the requisite performance was compiled. This list was based on an in-house evaluation of designs. Following the establishment of these options, a technical evaluation of the designs selected was conducted. In parallel with their evaluations, MTI focused on the establishment of commercial sources.

  8. HIGH SPEED KERR CELL FRAMING CAMERA

    DOEpatents

    Goss, W.C.; Gilley, L.F.

    1964-01-01

    The present invention relates to a high speed camera utilizing a Kerr cell shutter and a novel optical delay system having no moving parts. The camera can selectively photograph at least 6 frames within 9 x 10/sup -8/ seconds during any such time interval of an occurring event. The invention utilizes particularly an optical system which views and transmits 6 images of an event to a multi-channeled optical delay relay system. The delay relay system has optical paths of successively increased length in whole multiples of the first channel optical path length, into which optical paths the 6 images are transmitted. The successively delayed images are accepted from the exit of the delay relay system by an optical image focusing means, which in turn directs the images into a Kerr cell shutter disposed to intercept the image paths. A camera is disposed to simultaneously view and record the 6 images during a single exposure of the Kerr cell shutter. (AEC)

  9. High-speed digital wireless battlefield network

    NASA Astrophysics Data System (ADS)

    Dao, Son K.; Zhang, Yongguang; Shek, Eddie C.; van Buer, Darrel

    1999-07-01

    In the past two years, the Digital Wireless Battlefield Network consortium that consists of HRL Laboratories, Hughes Network Systems, Raytheon, and Stanford University has participated in the DARPA TRP program to leverage the efforts in the development of commercial digital wireless products for use in the 21st century battlefield. The consortium has developed an infrastructure and application testbed to support the digitized battlefield. The consortium has implemented and demonstrated this network system. Each member is currently utilizing many of the technology developed in this program in commercial products and offerings. These new communication hardware/software and the demonstrated networking features will benefit military systems and will be applicable to the commercial communication marketplace for high speed voice/data multimedia distribution services.

  10. Very high speed cw digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Pérez-López, Carlos; de La Torre-Ibarra, Manuel H.; Mendoza Santoyo, Fernando

    2006-10-01

    It is reported for the first time the use of a very high speed camera in digital holographic interferometry with an out of plane sensitivity setup. The image plane holograms of a spherical latex balloon illuminated by a cw laser were acquired at a rate of 4000 frames per second, representing a time spacing between holograms of 250 microseconds, for 512 × 512 pixels at 8 bits resolution. Two types of tests were accomplished for a proof of principle of the technique, one with no constrains on the object which meant random movements due to non controlled environmental air currents, and the other with specific controlled conditions on the object. Results presented correspond to a random sample of sequential digital holograms, chosen from a 1 second exposure, individually Fourier processed in order to perform the usual comparison by subtraction between consecutive pairs thus obtaining the phase map of the object out of plane displacement, shown as a movie.

  11. High speed nanotechnology-based photodetector

    NASA Astrophysics Data System (ADS)

    Kurtz, Russell M.; Pradhan, Ranjit D.; Parfenov, Alexander V.; Holmstedt, Jason; Esterkin, Vladimir; Menon, Naresh; Aye, Tin M.; Chua, Kang-Bin; Schindler, Axel; Balandin, Alexander A.; Nichter, James E.

    2005-08-01

    An inexpensive, easily integrated, 40 Gbps photoreceiver operating in the communications band would revolutionize the telecommunications industry. While generation of 40 Gbps data is not difficult, its reception and decoding require specific technologies. We present a 40 Gbps photoreceiver that exceeds the capabilities of current devices. This photoreceiver is based on a technology we call "nanodust." This new technology enables nanoscale photodetectors to be embedded in matrices made from a different semiconductor, or directly integrated into a CMOS amplification circuit. Photoreceivers based on quantum dust technology can be designed to operate in any spectral region, including the telecommunications bands near 1.31 and 1.55 micrometers. This technology also lends itself to normal-incidence detection, enabling a large detector size with its associated increase in sensitivity, even at high speeds and reception wavelengths beyond the capability of silicon.

  12. Photodetector having high speed and sensitivity

    DOEpatents

    Morse, Jeffrey D.; Mariella, Jr., Raymond P.

    1991-01-01

    The present invention provides a photodetector having an advantageous combination of sensitivity and speed; it has a high sensitivity while retaining high speed. In a preferred embodiment, visible light is detected, but in some embodiments, x-rays can be detected, and in other embodiments infrared can be detected. The present invention comprises a photodetector having an active layer, and a recombination layer. The active layer has a surface exposed to light to be detected, and comprises a semiconductor, having a bandgap graded so that carriers formed due to interaction of the active layer with the incident radiation tend to be swept away from the exposed surface. The graded semiconductor material in the active layer preferably comprises Al.sub.1-x Ga.sub.x As. An additional sub-layer of graded In.sub.1-y Ga.sub.y As may be included between the Al.sub.1-x Ga.sub.x As layer and the recombination layer. The recombination layer comprises a semiconductor material having a short recombination time such as a defective GaAs layer grown in a low temperature process. The recombination layer is positioned adjacent to the active layer so that carriers from the active layer tend to be swept into the recombination layer. In an embodiment, the photodetector may comprise one or more additional layers stacked below the active and recombination layers. These additional layers may include another active layer and another recombination layer to absorb radiation not absorbed while passing through the first layers. A photodetector having a stacked configuration may have enhanced sensitivity and responsiveness at selected wavelengths such as infrared.

  13. Computation of high-speed reacting flows

    NASA Astrophysics Data System (ADS)

    Clutter, James Keith

    A computational study has been conducted for high-speed reacting flows relevant to munition problems, including shock-induced combustion and gun muzzle blast. The theoretical model considers inviscid and viscous flows, multi-species, finite rate chemical reaction schemes, and turbulence. Both the physical and numerical aspects are investigated to determine their impact on simulation accuracy. A range of hydrogen and oxygen reaction mechanisms are evaluated for the shock-induced combustion flow scenario. Characteristics of the mechanisms such as the induction time, heat release rate, and second explosion limit are found to impact the accuracy of the computation. On the numerical side, reaction source term treatments, including logarithmic weighting and scaling modifications, are investigated to determine their effectiveness in addressing numerical errors caused by disparate length scales between chemical reactions and fluid dynamics. It is demonstrated that these techniques can enhance solution accuracy. Computations of shock-induced combustion have also been performed using a κ-ɛ model to account for the turbulent transport of species and heat. An algebraic model of the temperature fluctuations has been used to estimate the impact of the turbulent effect on the chemical reaction source terms. The turbulence effects when represented with the current models are found to be minimal in the shock-induced combustion flow investigated in the present work. For the gun system simulations, computations for both a large caliber howitzer and small caliber firearms are carried out. A reduced kinetic scheme and an algebraic turbulence model are employed. The present approach, which accounts for the chemical reaction aspects of the gun muzzle blast problem, is found to improve the prediction of peak overpressures and can capture the effects produced by small caliber firearm sound suppressors. The present study has established the numerical and physical requirements for

  14. Photogrammetric Techniques Using High-Speed Cineradiography

    NASA Astrophysics Data System (ADS)

    Nusholtz, Guy S.; Bender, Max; Suggitt, Bryan R.; Kaiker, Patricia S.; Muscott, Gail J.

    1986-01-01

    A high-speed 16-mm cineradiographic system previously developed at the University of Michigan Transportation Research Institute for use in biomechanics research has been undergoing a continuous upgrading in capability. In addition to changes in the structural aspect of the cineradiography, improvements have been made in the procedures used to obtain better image quality as well as methods for interpretation of the digitized results. The current improvements in the system include: 1) filtering the X-ray source before penetration of the subject to increase image contrast as well as to protect the image tube; 2) pre-processing of the film to increase its effective speed; 3) development of a neutral density radio-contrast media for outlining anatomical structure without using the vascular system; and 4) development of procedures for obtaining analytical information about motion of non-rigid anatomical structures from digitized film. This system now consists of either a 35-mm Photosonics 4B, a 16-mm Photosonics 1B, or a 16-mm Milliken which views a 50-mm (2-inch) diameter output of a P-11 phosphor of a high gain, four-stage magnetically focused image intensifier tube, gated on and off synchronously with the motion picture camera shutter. A lens optically couples the input photocathode of the image tube to an X-ray fluorescent (rare earth) screen image produced by a smoothed DC X-ray generator of a conventional type. The system is capable of looking at a large spectrum of anatomical structures under a wide range of dynamic loading conditions.

  15. High-speed shutter for mirror cameras

    NASA Astrophysics Data System (ADS)

    Trofimenko, Vladimir V.; Klimashin, V. P.; Drozhbin, Yu. A.

    1999-06-01

    High-speed mirror cameras are mainly used for investigations of quick processes in a wide spectral range of radiation including ultraviolet and infrared regions (from 0.2 to 11 micrometer). High-speed shutters for these cameras must be non-selective and when opened must transmit the whole radiation without refraction, absorption and scattering. Electromechanical, electrodynamic and induction-dynamic shutters possess such properties because their optical channels contain no medium. Electromechanical shutters are devices where the displacement of the working blind which opens or closes an aperture is produced by a spring. Such shutters are relatively slow and are capable of closing an aperture of 50 mm in diameter in 10 - 15 ms. Electrodynamic and induction-dynamic shutters are devices where displacement of a blind is produced by the electromagnetic interaction between circuits with electric currents. In induction-dynamic shutter the secondary circuit is current-conducting blind itself in which a short-circuited loop forms. The latter is more quick because of the lower mass of its moveable secondary circuit. For this reason induction-dynamic shutters with a flat primary circuit coil and a tightly fitted to it load- bearing aluminum plate have been investigated. The blind which opens or closes an aperture was attached to this plate. The dependencies of cut-off time on the form, size and the number of turns of the primary circuit coil, on size, type of material, thickness and weight of the load-bearing plate and the blind, as well as on capacitance in the discharge circuit and the capacitor voltage have been investigated. The influence of the environmental atmosphere on the cut-off time was also studied. For this purpose the shutter was placed into the chamber where vacuum up to 10- atm could be produced. As a result the values of the above mentioned parameters have been optimized and the designs of the shutters which are shown have been developed.

  16. High Speed/ Low Effluent Process for Ethanol

    SciTech Connect

    M. Clark Dale

    2006-10-30

    n this project, BPI demonstrated a new ethanol fermentation technology, termed the High Speed/ Low Effluent (HS/LE) process on both lab and large pilot scale as it would apply to wet mill and/or dry mill corn ethanol production. The HS/LE process allows very rapid fermentations, with 18 to 22% sugar syrups converted to 9 to 11% ethanol ‘beers’ in 6 to 12 hours using either a ‘consecutive batch’ or ‘continuous cascade’ implementation. This represents a 5 to 8X increase in fermentation speeds over conventional 72 hour batch fermentations which are the norm in the fuel ethanol industry today. The ‘consecutive batch’ technology was demonstrated on a large pilot scale (4,800 L) in a dry mill corn ethanol plant near Cedar Rapids, IA (Xethanol Biofuels). The pilot demonstrated that 12 hour fermentations can be accomplished on an industrial scale in a non-sterile industrial environment. Other objectives met in this project included development of a Low Energy (LE) Distillation process which reduces the energy requirements for distillation from about 14,000 BTU/gal steam ($0.126/gal with natural gas @ $9.00 MCF) to as low as 0.40 KW/gal electrical requirements ($0.022/gal with electricity @ $0.055/KWH). BPI also worked on the development of processes that would allow application of the HS/LE fermentation process to dry mill ethanol plants. A High-Value Corn ethanol plant concept was developed to produce 1) corn germ/oil, 2) corn bran, 3) ethanol, 4) zein protein, and 5) nutritional protein, giving multiple higher value products from the incoming corn stream.

  17. High-speed 3D imaging by parallel phase-shifting digital holography

    NASA Astrophysics Data System (ADS)

    Awatsuji, Yasuhiro; Xia, Peng; Matoba, Osamu

    2015-07-01

    As a high-speed three-dimensional (3D) imaging technique, parallel phase-shifting digital holography is presented. This technique records a single hologram of an object with an image sensor having a phase-shift array device and reconstructs the instantaneous 3D image of the object with a computer. In this technique, a single hologram in which the multiple holograms required for phase-shifting digital holography are multiplexed by using space-division multiplexing technique pixel by pixel. Also, we present a high-speed parallel phase-shifting digital holography system. The system consists of an interferometer, a continuous-wave laser, and a high-speed polarization imaging camera. Motion pictures of dynamic phenomena at the rate of up to 1,000,000 frames per second have been achieved by the high-speed system.

  18. Elucidation of phenomena in high-power fiber laser welding and development of prevention procedures of welding defects

    NASA Astrophysics Data System (ADS)

    Katayama, Seiji; Kawahito, Yousuke

    2009-02-01

    Fiber lasers have been receiving considerable attention because of their advantages of high power, high beam quality and high efficiency, and are expected as one of the desirable heat sources for high-speed and deep-penetration welding. In our researches, therefore, the effects of laser powers and their densities on the weld penetration and the formation of sound welds were investigated in welding of Type 304 austenitic stainless steel, A5052 aluminum alloy or high strength steel plates with four laser beams of about 0.12 to 1 mm in focused spot diameter, and their welding phenomena were observed with high-speed video cameras and X-ray transmission real-time imaging system. It was found that the laser power density exerted a remarkable effect on the increase in weld penetration at higher welding speeds, but on the other hand at low welding speeds deeper-penetration welds could be produced at higher power. Laser-induced plume behavior and its effect on weld penetration, and the mechanisms of spattering, underfilling, porosity and humping were elucidated, sound welds without welding defects could be produced under the improved welding conditions. In addition, importance of the development of focusing optics and the removal of a plume during remote welding will be emphasized in terms of the stable production of constant deep-penetration welds and the reduction in welding defects in high power laser welding.

  19. Short pulse generation and high speed communication system

    NASA Astrophysics Data System (ADS)

    Fan, Honglei

    Ultrahigh-speed optical time-division-multiplexing (TDM) transmission technologies are essential to construct ultrahigh-speed all-optical networks needed in the multimedia era. In order to realize high-speed optical TDM systems, ultra-short pulses should be generated. In this dissertation, the gain switching and mode locking techniques have been analyzed and used to produce ultra- short pulses. Gain-switched pulses with a width of ~18ps have been obtained. The theoretical analysis on gain-switching phenomena has been carried out. A new approach for the simulation of the spectrum of a gain- switched laser has been developed. The principle of mode locking has been discussed. ~6.5ps, pulses have been obtained from a monolithic mode-locked distributed Bragg reflector (DBR) laser, which are the shortest pulses from the actively mode- locked DBR lasers as we know. ~1.1ps pulses have been achieved from a colliding-pulse mode-locked (CPM) laser. The operation principle of CPM lasers has been discussed. Pulse compression using dispersion-compensating fiber has been applied in order to get shorter pulses. The semiconductor optical amplifier (SOA) plays a very important role in TDM systems. The cross gain modulation (XGM) measurements on a 2-section SOA, using both cw and pulsed pump and probe beams, have been performed. A theoretical analysis has been carried out. Wavelength conversion and fiber transmission experiments have been achieved at different bit rates. The basic idea of TDM system has been discussed. Multiplexing has been achieved using fibers. Demulitplexing has been demonstrated using XGM in SOA, four-wave mixing (FWM) in SOA, and cascaded modulators. The operation principles have been discussed in detail. The FWM experiments between two optical pulses have been performed.

  20. 8-Foot High Speed Tunnel (HST

    NASA Technical Reports Server (NTRS)

    1957-01-01

    Interior view of the slotted throat test section installed in the 8-Foot High Speed Tunnel (HST) in 1950. The slotted region is about 160 inches in length. In this photograph, the sting-type model support is seen straight on. In a NASA report, the test section is described as follows: 'The test section of the Langley 8-foot transonic tunnel is dodecagonal in cross section and has a cross-sectional area of about 43 square feet. Longitudinal slots are located between each of the 12 wall panels to allow continuous operation through the transonic speed range. The slots contain about 11 percent of the total periphery of the test section. Six of the twelve panels have windows in them to allow for schlieren observations. The entire test section is enclosed in a hemispherical shaped chamber.' John Becker noted that the tunnel's 'final achievement was the development and use in routine operations of the first transonic slotted throat. The investigations of wing-body shapes in this tunnel led to Whitcomb's discovery of the transonic area rule.' James Hansen described the origins of the the slotted throat as follows: 'In 1946 Langley physicist Ray H. Wright conceived a way to do transonic research effectively in a wind tunnel by placing slots in the throat of the test section. The concept for what became known as the slotted-throat or slotted-wall tunnel came to Wright not as a solution to the chronic transonic problem, but as a way to get rid of wall interference (i.e., the mutual effect of two or more meeting waves or vibrations of any kind caused by solid boundaries) at subsonic speeds. For most of the year before Wright came up with this idea, he had been trying to develop a theoretical understanding of wall interference in the 8-Foot HST, which was then being repowered for Mach 1 capability.' When Wright presented these ideas to John Stack, the response was enthusiastic but neither Wright nor Stack thought of slotted-throats as a solution to the transonic problem, only

  1. High speed image correlation for vibration analysis

    NASA Astrophysics Data System (ADS)

    Siebert, T.; Wood, R.; Splitthof, K.

    2009-08-01

    Digital speckle correlation techniques have already been successfully proven to be an accurate displacement analysis tool for a wide range of applications. With the use of two cameras, three dimensional measurements of contours and displacements can be carried out. With a simple setup it opens a wide range of applications. Rapid new developments in the field of digital imaging and computer technology opens further applications for these measurement methods to high speed deformation and strain analysis, e.g. in the fields of material testing, fracture mechanics, advanced materials and component testing. The high resolution of the deformation measurements in space and time opens a wide range of applications for vibration analysis of objects. Since the system determines the absolute position and displacements of the object in space, it is capable of measuring high amplitudes and even objects with rigid body movements. The absolute resolution depends on the field of view and is scalable. Calibration of the optical setup is a crucial point which will be discussed in detail. Examples of the analysis of harmonic vibration and transient events from material research and industrial applications are presented. The results show typical features of the system.

  2. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false High speed characteristics. 23.253 Section 23.253 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established...

  3. High speed exhaust gas recirculation valve

    SciTech Connect

    Fensom, Rod; Kidder, David J.

    2005-01-18

    In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

  4. Material constraints on high-speed design

    NASA Astrophysics Data System (ADS)

    Bucur, Diana; Militaru, Nicolae

    2015-02-01

    Current high-speed circuit designs with signal rates up to 100Gbps and above are implying constraints for dielectric and conductive materials and their dependence of frequency, for component elements and for production processes. The purpose of this paper is to highlight through various simulation results the frequency dependence of specific parameters like insertion and return loss, eye diagrams, group delay that are part of signal integrity analyses type. In low-power environment designs become more complex as the operation frequency increases. The need for new materials with spatial uniformity for dielectric constant is a need for higher data rates circuits. The fiber weave effect (FWE) will be analyzed through the eye diagram results for various dielectric materials in a differential signaling scheme given the fact that the FWE is a phenomenon that affects randomly the performance of the circuit on balanced/differential transmission lines which are typically characterized through the above mentioned approaches. Crosstalk between traces is also of concern due to propagated signals that have tight rise and fall times or due to high density of the boards. Criteria should be considered to achieve maximum performance of the designed system requiring critical electronic properties.

  5. Complex Three-Dimensional Turbulent Flow Phenomena of High-Alpha Projectile Aerodynamics

    NASA Astrophysics Data System (ADS)

    Chen, Guang-Wu.

    An impulsively started turbulent flow of Mach 0.96 past a Secant-Ogive-Cylinder-Boattail projectile model with sting at 60-degree angle of attack is considered for investigating the complex three-dimensional vortical flow physics and phenomena. The governing equations used for the vortical flow simulation are the Reynolds-averaged thin-layer Navier-Stokes equations implemented with a modified Baldwin-Lomax algebraic eddy viscosity model for ideal gases. The turbulence model has been shown to provide an acceptably accurate surface pressure distribution in the crossflow separation region by Degani and Schiff. The implication of the turbulence model for a proper description of flow solutions away from the boundary-layer region has been intensively investigated in this study. The comparison of the simulated flow characteristics against those obtained from employing the original Baldwin-Lomax model clearly shows that the modified turbulence model employed in this study can give at least qualitatively correct vortical flow physics and phenomena. In this study the numerical simulation has revealed a number of interesting and important fundamental characteristics of complex vortical flow. The onset times for primary and secondary crossflow separations are found to be linearly dependent on the diameter of the cross-section. The evolution of the crossflow vortex patterns on the cylinder, boattail and sting sections of the projectile shows a transition from a stable node to an unstable spiral through the appearance of a stable limiting cycle. The unstable spiral vortex on the ogive; however, is formed through an entirely different mechanism, consisting of a two-saddle-point flow structure. It is also shown that the development of primary vortices has induced a high speed axial jet stream in the leeward side of the ogive and cylinder sections. Moreover, the alternating vortex shedding is simulated on the projectile sting and the shedding frequency in terms of the Strouhal

  6. High-Speed Data Recorder for Space, Geodesy, and Other High-Speed Recording Applications

    NASA Technical Reports Server (NTRS)

    Taveniku, Mikael

    2013-01-01

    A high-speed data recorder and replay equipment has been developed for reliable high-data-rate recording to disk media. It solves problems with slow or faulty disks, multiple disk insertions, high-altitude operation, reliable performance using COTS hardware, and long-term maintenance and upgrade path challenges. The current generation data recor - ders used within the VLBI community are aging, special-purpose machines that are both slow (do not meet today's requirements) and are very expensive to maintain and operate. Furthermore, they are not easily upgraded to take advantage of commercial technology development, and are not scalable to multiple 10s of Gbit/s data rates required by new applications. The innovation provides a softwaredefined, high-speed data recorder that is scalable with technology advances in the commercial space. It maximally utilizes current technologies without being locked to a particular hardware platform. The innovation also provides a cost-effective way of streaming large amounts of data from sensors to disk, enabling many applications to store raw sensor data and perform post and signal processing offline. This recording system will be applicable to many applications needing realworld, high-speed data collection, including electronic warfare, softwaredefined radar, signal history storage of multispectral sensors, development of autonomous vehicles, and more.

  7. High-speed non-intrusive measurements of fuel velocity fields at high-pressure injectors

    NASA Astrophysics Data System (ADS)

    Gürtler, Johannes; Schlüßler, Raimund; Fischer, Andreas; Czarske, Jürgen

    2017-03-01

    Using a single high-speed camera and a frequency modulated laser, a novel approach is presented for fast velocity field measurements in unsteady spray flows. The velocity range is from zero up to several 100 m/s, which requires a high measurement rate and a large dynamic. Typically, flow measurements require to seed tracer particles to the fluid. A paradigm shift to seeding-free measurements is presented. The light scattered at the phase boundaries of the fluid droplets is evaluated. In order to validate the high-speed measurement system, a detailed uncertainty analysis is performed by means of measurements as well as simulations. Thereby, variations of the scattered light intensity, which are based on the high temporal velocity gradients, are found to be the main contribution to the uncertainty. The eventually measurement results, obtained at a measurement rate of 500 kHz, exhibit spray velocities ranging from 0 m/s up to 400 m/s in less than 1 ms, and the detection of unsteady and irregular flow phenomena with a characteristic time of several μs is achieved. This demonstrates the high measurement rate, the high temporal resolution and the large measurement range of the proposed high-speed measurement system.

  8. High-speed imaging of sound using parallel phase-shifting interferometry.

    PubMed

    Ishikawa, Kenji; Yatabe, Kohei; Chitanont, Nachanant; Ikeda, Yusuke; Oikawa, Yasuhiro; Onuma, Takashi; Niwa, Hayato; Yoshii, Minoru

    2016-06-13

    Sound-field imaging, the visualization of spatial and temporal distribution of acoustical properties such as sound pressure, is useful for understanding acoustical phenomena. This study investigated the use of parallel phase-shifting interferometry (PPSI) with a high-speed polarization camera for imaging a sound field, particularly high-speed imaging of propagating sound waves. The experimental results showed that the instantaneous sound field, which was generated by ultrasonic transducers driven by a pure tone of 40 kHz, was quantitatively imaged. Hence, PPSI can be used in acoustical applications requiring spatial information of sound pressure.

  9. High speed imaging technology: yesterday, today, and tomorrow

    NASA Astrophysics Data System (ADS)

    Pendley, Gil J.

    2003-07-01

    The purpose of this discussion is to familiarize readers with an overview of high-speed imaging technology as a means of analyzing objects in motion that occur too fast for the eye to see or conventional photography or video to capture. This information is intended to provide a brief historical narrative from the inception of high-speed imaging in the USA and the acceptance of digital video technology to augment or replace high-speed motion picture cameras. It is not intended a definitive work on the subject. For those interested in greater detail, such as application techniques, formulae, very high-speed and ultra speed technology etc. I recommend the latest text on the subject: High Speed Photography and Photonics first published in 1997 by Focal Press in the UK and copyrighted by the Association for High Speed Photography in the United Kingdom.

  10. Analysis of coupling between high-speed railway and common speed railway system in transportation corridor

    NASA Astrophysics Data System (ADS)

    Zhou, Hongchang; Li, Haijun; Chen, Xiaohong; Zhu, Changfeng

    2017-04-01

    The high-speed railway and common speed railway subsystems as important components of the railway transportation system, can make railway traffic organization more orderly, when there are a rational division and balance development between them. In order to quantitatively evaluate the coordinate relations between high-speed railway subsystem and common speed railway subsystem, this paper takes the railway transportation corridor from Baoji to Lanzhou as an example. Firstly, using Logit model and grey forecasting model predict the passenger volume, passenger turnover and time value of high-speed railway and common speed railway in the Baoji-Lanzhou corridor. And then, the coupling forecast model of these two subsystems is established. Lastly, the coupling and coupling coordination of these two subsystems using are predicted and analyzed at theatrically level.

  11. The unstable behavior of low and high-speed compressors

    SciTech Connect

    Day, I.J. . Whittle Lab.); Freeman, C. )

    1994-04-01

    By far the greater part of the understanding about stall and surge in axial compressors comes from work on low-speed laboratory machines. As a general rule, these machines do not model the compressibility effects present in high-speed compressors and therefore doubt has always existed about the application of low-speed results to high-speed machines. In recent years interest in active control has led to a number of studies of compressor stability in engine-type compressors. The instrumentation used in these experiments has been sufficiently detailed that, for the first time, adequate data are available to make direct comparisons between high-speed and low-speed compressors. This paper presents new data from an eight-stage fixed geometry engine compressor and compares then with low-speed laboratory data. The results show remarkable similarities in both the stalling and surging behavior of the two machines, particularly when the engine compressor is run at intermediate speeds. The engine results also show that, as in the laboratory tests, surge is precipitated by the onset of rotating stall. This is true even at very high speeds where it had previously been thought that surge might be the result of a blast wave moving through the compressor. This paper therefore contains new information about high-speed compressors and confirms that low-speed testing is an effective means of obtaining insight into the behavior of high-speed machines.

  12. High-speed cinematography of muscle contraction.

    PubMed

    HAUPT, R E; WALL, D M

    1962-07-13

    Motion pictures of the "twitch" of an excised frog gastrocnemius muscle taken at rates of 6000 frames per second provide a means of very accurately timing the phases. The extreme "slow motion" reveals surface phenomena not observable by other techniques. Evidence of "active relaxation" is suggested by results of frame-by-frame analysis.

  13. The high speed civil transport and NASA's High Speed Research (HSR) program

    NASA Technical Reports Server (NTRS)

    Shaw, Robert J.

    1994-01-01

    Ongoing studies being conducted not only in this country but in Europe and Asia suggest that a second generation supersonic transport, or High-Speed Civil Transport (HSCT), could become an important part of the 21st century international air transportation system. However, major environmental compatibility and economic viability issues must be resolved if the HSCT is to become a reality. This talk will overview the NASA High-Speed Research (HSR) program which is aimed at providing the U.S. industry with a technology base to allow them to consider launching an HSCT program early in the next century. The talk will also discuss some of the comparable activities going on within Europe and Japan.

  14. How to Combine Engines to Achieve High Speed, Hypersonic Speed, Speed of Light and Even Higher-Applications

    NASA Astrophysics Data System (ADS)

    Mwizerwa, Celestin; Nishimwe, Celestine

    2014-03-01

    When Einstein left us, he left us a really big problem to solve, does anything can travel faster than the speed of light? There hasn't been any way to try this in the past, because there were any technology which could accelerate objects at this speed. What researchers tried to do, was to accelerate particles. But there must be a way to play with speeds so that, as we do math, we may practically multiply the speed by any number we want, we also may practically divide the speed by any number we want. In this paper I will try to show how. Also, In our real life, there might be a need of such high speeds, so that a lot of problems may be solved, as for example the airplane technology, electric power, space travel, car transmission, industrial high temperature and so on ...I do not say for sure that, the object will move faster than the speed of light, but, people who have ability may try to accelerate it at this speed and even faster to see what will happen as now it is very easy to realize. There are two ways; you go to space to do it or, you create a vacuum and move it inside.

  15. High speed point derivative microseismic detector

    DOEpatents

    Uhl, James Eugene; Warpinski, Norman Raymond; Whetten, Ernest Blayne

    1998-01-01

    A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves.

  16. High speed point derivative microseismic detector

    DOEpatents

    Uhl, J.E.; Warpinski, N.R.; Whetten, E.B.

    1998-06-30

    A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves. 9 figs.

  17. Computation of High Speed Jet Noise

    NASA Technical Reports Server (NTRS)

    Freund, Jonathan B.

    2002-01-01

    The objective of this work was to use direct numerical simulation (DNS) techniques to study the physics of noise generation by a high-speed turbulent jet. A Mach 0.9, Reynolds number 3,600 jet was selected because of available experimental data. New numerical methods for generating disturbances at the nozzle and computing far-field sound were developed and reported in the course of this work. Over 25 million mesh points were used in the simulations which ran for over 50,000 timesteps and required over 50,000 processor hours on state-of-the-art parallel computer systems to complete. Figures show a visualization of the jet and sound field, a comparison of the mean flow development with the experiment, a directivity comparison with the experiment, and time spectrum comparison with the experiment. Agreement is seen to be excellent. These are fully document in the attached references. Full details of the work, detailed achievements and conclusions are discussed in appendices, which are copies of publications that resulted from this work. We have studied noise mechanisms in supersonic jets, the refraction of sound by turbulence in subsonic jets, and noise sources in conjunction with a DNS of a Mach 0.9 jet.

  18. 8-Foot High Speed Tunnel (HST)

    NASA Technical Reports Server (NTRS)

    1953-01-01

    Semi-automatic readout equipment installed in the 1950s used for data recording and reduction in the 8-Foot High Speed Tunnel (HST). A 1957 NACA report on wind tunnel facilities at Langley included these comments on the data recording and reduction equipment for the 8-foot HST: 'The data recording and reduction equipment used for handling steady force and pressure information at the Langley 8-foot transonic tunnel is similar to that described for the Langley 16-foot transonic tunnel. Very little dynamic data recording equipment, however, is available.' The description of the 16-foot transonic tunnel equipment is as follows: 'A semiautomatic force data readout system provides tabulated raw data and punch card storage of raw data concurrent with the operation of the wind tunnel. Provision is made for 12 automatic channels of strain gage-data output, and eight channels of four-digit manually operated inputs are available for tabulating and punching constants, configuration codes, and other information necessary for data reduction and identification. The data are then processed on electronic computing machines to obtain the desired coefficients. These coefficients and their proper identification are then machine tabulated to provide a printed record of the results. The punched cards may also be fed into an automatic plotting device for the preparation of plots necessary for data analysis.'

  19. High-transonic-speed transport aircraft study

    NASA Technical Reports Server (NTRS)

    Kulfan, R. M.

    1974-01-01

    An initial design study of high-transonic-speed transport aircraft has been completed. Five different design concepts were developed. These included fixed swept wing, variable-sweep wing, delta wing, double-fuselage yawed-wing, and single-fuselage yawed-wing aircraft. The boomless supersonic design objectives of range = 5560 km (3000 nmi), payload = 18,143 kg (40,000 lb), Mach = 1.2, and FAR Part 36 aircraft noise levels were achieved by the single-fuselage yawed-wing configuration with a gross weight of 211,828 kg (467,000 lb). A noise level of 15 EPNdB below FAR Part 36 requirements was obtained with a gross weight increase to 226,796 kg (500,000 lb). The off-design subsonic range capability for this configuration exceeded the Mach 1.2 design range by more than 20%. Although wing aeroelastic divergence was a primary design consideration for the yawed-wing concepts, the graphite-epoxy wings of this study were designed by critical gust and maneuver loads rather than by divergence requirements. The transonic nacelle drag is shown to be very sensitive to the nacelle installation. A six-degree-of-freedom dynamic stability analysis indicated that the control coordination and stability augmentation system would require more development than for a symmetrical airplane but is entirely feasible. A three-plane development plan is recommended to establish the full potential of the yawed-wing concept.

  20. High speed imaging in icing windtunnel tests

    NASA Astrophysics Data System (ADS)

    de Pauw, Dennis; Graham, Percival; Dolatabadi, Ali

    2012-11-01

    The detailed visualization and behavior of a spray impinging on a hydrophilic, and superhydrophobic aerodynamic shape in isothermal room and icing conditions can provide deep understanding of in-flight icing. A superhydrophobic coating has a very low surface energy so it can be used to counteract the ice accumulation. It also reduces the adhesion strength of ice to the surface which ensures easier removal of the ice during flight. The focus of the experiments primarily lies on the fundamental study of multiple droplet, i.e. spray, impact on a NACA 0012 airfoil in room and icing conditions. Under such conditions, important icing features such as rivulets and runback flow are observed. This provides us with the basics of ice formation on an aerodynamic surface. The study also focuses on the comparison between aluminum and superhydrophobic surfaces for ice accumulation in conditions which approach flight conditions. All the experiments are carried out in a small scale icing windtunnel using high speed photography with frame rates ranging from five thousand to fifty thousand frames per second.

  1. Flickering aurora studies using high speed cameras

    NASA Astrophysics Data System (ADS)

    McHarg, M. G.; Stenbaek-Nielsen, H. C.; Samara, M.; Michell, R.; Hampton, D. L.; Haaland, R. K.

    2009-12-01

    We report on observations of flickering aurora using two different digital camera systems. The first, a high speed Phantom 7 camera with a Video Scope HS 1845 HS image intensifier coupled with an 50mm lens provides fast frame rates with data recorded at 200 and 400 frames per second with a 512x384 pixel, 11.8x8.8 degree FOV. The second system is an Andor Electron-Multiplying Charge Couple Device (EMCCD) running at 33 frames per second using a 256 by 256 format covering 16x16 degrees field of view. Both systems made observations of flickering aurora in the magnetic zenith, using optical filters transmitting the prompt blue and red emissions of nitrogen. The Andor system was deployed at the Poker Flat rocket range near Fairbanks AK, while the Phantom system was deployed approximately 400 miles north of Poker Flat at Toolik Lake observatory. We find both narrow band low frequency (~5-10 Hz) and wider band, higher frequency (50- 70 Hz) oscillations in the optical intensity of flickering aurora. Direct comparison of the optical data and the dispersion relation for ion cyclotron waves thought to be responsible for the modulation of electrons causing the intensity fluctuations seen in flickering aurora are presented.

  2. High speed ground transportation study. Executive summary

    SciTech Connect

    Not Available

    1992-10-01

    In 1991, the Washington State Legislature enacted Chapter 231, Laws of 1991 (SHB 1452), which directed that a comprehensive assessment be made of the feasibility of developing a high speed ground transportation (HSGT) system in the State of Washington. The legislation came about because there was a growing recognition that major transportation corridors were reaching unacceptable levels of congestion, and that even though most large metropolitan areas were developing specific plans to ease that congestion within their urban boundaries, intercity travel between those areas was becoming increasingly difficult. The study area included the State of Washington plus the Portland, OR urban area and the lower mainland of British Columbia. Two major corridors were identified and analyzed. The study was not meant to focus on the technologies but rather on the economic, environmental, institutional and financial feasibility of implementing HSGT in this state. The study was not meant to be a siting study. Alignments and station locations were assumed only to test feasibility, and to evaluate corridors and service areas. Specific location decisions will require more detailed engineering and operations studies.

  3. Enhanced high-speed coherent diffraction imaging

    NASA Astrophysics Data System (ADS)

    Potier, Jonathan; Fricker, Sebastien; Idir, Mourad

    2011-03-01

    Due to recent advances in X-ray microscopy, we are now able to image objects with nanometer resolution thanks to Synchrotron beam lines or Free Electron Lasers (FEL). The PCI (Phase Contrast Imaging) is a robust technique that can recover the wavefront from measurements of only few intensity pictures in the Fresnel diffraction region. With our fast straightforward calculus methods, we manage to provide the phase induced by a microscopic specimen in few seconds. We can therefore obtain high contrasted images from transparent materials at very small scales. To reach atomic resolution imaging and thus make a transition from the near to the far field, the Coherent Diffraction Imaging (CDI) technique finds its roots in the analysis of diffraction patterns to obtain the phase of the altered complex wave. Theoretical results about existence and uniqueness of this retrieved piece of information by both iterative and direct algorithms have already been released. However, performances of algorithms remain limited by the coherence of the X-ray beam, presence of random noise and the saturation threshold of the detector. We will present reconstructions of samples using an enhanced version of HIO algorithm improving the speed of convergence and its repeatability. As a first step toward a practical X-Ray CDI system, initial images for reconstructions are acquired with the laser-based CDI system working in the visible spectrum.

  4. High speed curved position sensitive detector

    DOEpatents

    Hendricks, Robert W.; Wilson, Jack W.

    1989-01-01

    A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

  5. High speed radiometric measurements of IED detonation fireballs

    NASA Astrophysics Data System (ADS)

    Spidell, Matthew T.; Gordon, J. Motos; Pitz, Jeremey; Gross, Kevin C.; Perram, Glen P.

    2010-04-01

    Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step in moving from "laboratory" measurements to a rugged, fieldable system. To explore phenomena not observable in previous experiments, a high speed (10μs resolution) radiometer with four channels spanning the infrared spectrum observed the detonation of nine home made explosive (HME) devices in the < 100lb class. Radiometric measurements indicate that the detonation fireball is well approximated as a single temperature blackbody at early time (0 < t <~ 3ms). The effective radius obtained from absolute intensity indicates fireball growth at supersonic velocity during this time. Peak fireball temperatures during this initial detonation range between 3000.3500K. The initial temperature decay with time (t <~ 10ms) can be described by a simple phenomenological model based on radiative cooling. After this rapid decay, temperature exhibits a small, steady increase with time (10 <~ t <~ 50ms) and peaking somewhere between 1000.1500K-likely the result of post-detonation combustion-before subsequent cooling back to ambient conditions . Radius derived from radiometric measurements can be described well (R2 > 0.98) using blast model functional forms, suggesting that energy release could be estimated from single-pixel radiometric detectors. Comparison of radiometer-derived fireball size with FLIR infrared imagery indicate the Planckian intensity size estimates are about a factor of two smaller than the physical extent of the fireball.

  6. 8-Foot High Speed Tunnel (HST)

    NASA Image and Video Library

    1957-03-19

    Interior view of the slotted throat test section installed in the 8-Foot High Speed Tunnel (HST) in 1950. The slotted region is about 160 inches in length. In this photograph, the sting-type model support is seen straight on. In a NASA report, the test section is described as follows: The test section of the Langley 8-foot transonic tunnel is dodecagonal in cross section and has a cross-sectional area of about 43 square feet. Longitudinal slots are located between each of the 12 wall panels to allow continuous operation through the transonic speed range. The slots contain about 11 percent of the total periphery of the test section. Six of the twelve panels have windows in them to allow for schlieren observations. The entire test section is enclosed in a hemispherical shaped chamber. John Becker noted that the tunnel s final achievement was the development and use in routine operations of the first transonic slotted throat. The investigations of wing-body shapes in this tunnel led to Whitcomb s discovery of the transonic area rule. James Hansen described the origins of the the slotted throat as follows: In 1946 Langley physicist Ray H. Wright conceived a way to do transonic research effectively in a wind tunnel by placing slots in the throat of the test section. The concept for what became known as the slotted-throat or slotted-wall tunnel came to Wright not as a solution to the chronic transonic problem, but as a way to get rid of wall interference (i.e., the mutual effect of two or more meeting waves or vibrations of any kind caused by solid boundaries) at subsonic speeds. For most of the year before Wright came up with this idea, he had been trying to develop a theoretical understanding of wall interference in the 8-Foot HST, which was then being repowered for Mach 1 capability. When Wright presented these ideas to John Stack, the response was enthusiastic but neither Wright nor Stack thought of slotted-throats as a solution to the transonic problem, only the

  7. Novel collective phenomena in high-energy proton–proton and proton–nucleus collisions

    DOE PAGES

    Dusling, Kevin; Li, Wei; Schenke, Björn

    2016-01-22

    The observation of long-range rapidity correlations among particles in high-multiplicity p–p and p–Pb collisions created new opportunities for investigating novel high-density QCD phenomena in small colliding systems. We also review experimental results related to the study of collective phenomena in small systems at RHIC and the LHC along with the related developments in theory and phenomenology. Finally, perspectives on possible future directions for research are discussed with the aim of exploring emergent QCD phenomena.

  8. Chromotomosynthesis for high speed hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Bostick, Randall L.; Perram, Glen P.

    2012-09-01

    A rotating direct vision prism, chromotomosynthetic imaging (CTI) system operating in the visible creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a pointlike target show that performance is limited by chromatic aberration. The accuracy and utility of the instrument is assessed by comparing the CTI results to spatial data collected by a wideband image and hyperspectral data collected using a liquid crystal tunable filter (LCTF). The wide-band spatial content of the scene reconstructed from the CTI data is of same or better quality as a single frame collected by the undispersed imaging system with projections taken at every 1°. Performance is dependent on the number of projections used, with projections at 5° producing adequate results in terms of target characterization. The data collected by the CTI system can provide spatial information of equal quality as a comparable imaging system, provide high-frame rate slitless 1-D spectra, and generate 3-D hyperspectral imagery which can be exploited to provide the same results as a traditional multi-band spectral imaging system. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz. The instrument has considerable potential for characterizing bomb detonations, muzzle flashes, and other battlefield combustion events.

  9. Three-dimensional device characterization by high-speed cinematography

    NASA Astrophysics Data System (ADS)

    Maier, Claus; Hofer, Eberhard P.

    2001-10-01

    Testing of micro-electro-mechanical systems (MEMS) for optimization purposes or reliability checks can be supported by device visualization whenever an optical access is available. The difficulty in such an investigation is the short time duration of dynamical phenomena in micro devices. This paper presents a test setup to visualize movements within MEMS in real-time and in two perpendicular directions. A three-dimensional view is achieved by the combination of a commercial high-speed camera system, which allows to take up to 8 images of the same process with a minimum interframe time of 10 ns for the first direction, with a second visualization system consisting of a highly sensitive CCD camera working with a multiple exposure LED illumination in the perpendicular direction. Well synchronized this provides 3-D information which is treated by digital image processing to correct image distortions and to perform the detection of object contours. Symmetric and asymmetric binary collisions of micro drops are chosen as test experiments, featuring coalescence and surface rupture. Another application shown here is the investigation of sprays produced by an atomizer. The second direction of view is a prerequisite for this measurement to select an intended plane of focus.

  10. Calibration of GPS based high accuracy speed meter for vehicles

    NASA Astrophysics Data System (ADS)

    Bai, Yin; Sun, Qiao; Du, Lei; Yu, Mei; Bai, Jie

    2015-02-01

    GPS based high accuracy speed meter for vehicles is a special type of GPS speed meter which uses Doppler Demodulation of GPS signals to calculate the speed of a moving target. It is increasingly used as reference equipment in the field of traffic speed measurement, but acknowledged standard calibration methods are still lacking. To solve this problem, this paper presents the set-ups of simulated calibration, field test signal replay calibration, and in-field test comparison with an optical sensor based non-contact speed meter. All the experiments were carried out on particular speed values in the range of (40-180) km/h with the same GPS speed meter. The speed measurement errors of simulated calibration fall in the range of +/-0.1 km/h or +/-0.1%, with uncertainties smaller than 0.02% (k=2). The errors of replay calibration fall in the range of +/-0.1% with uncertainties smaller than 0.10% (k=2). The calibration results justify the effectiveness of the two methods. The relative deviations of the GPS speed meter from the optical sensor based noncontact speed meter fall in the range of +/-0.3%, which validates the use of GPS speed meter as reference instruments. The results of this research can provide technical basis for the establishment of internationally standard calibration methods of GPS speed meters, and thus ensures the legal status of GPS speed meters as reference equipment in the field of traffic speed metrology.

  11. Towards High Resolution Numerical Algorithms for Wave Dominated Physical Phenomena

    DTIC Science & Technology

    2009-01-30

    couple these elements using Finite- Volume-like surface Riemann solvers. This hybrid, dual-layer design allows DGTD to combine advantages from both of...electromagnetic waves , J. Comput. Phys., 114 (1994), pp. 185-200. [62] F. COLLINO, High order absorbing boundary conditions for wave propagation...formulation with high order absorbing boundary conditions for time-dependent waves , Comput. Meth. Appl. Mech., 195 (2006), pp. 3666-3690. [69] M. GUDDATI

  12. High Speed Balancing Applied to the T700 Engine

    NASA Technical Reports Server (NTRS)

    Walton, J.; Lee, C.; Martin, M.

    1989-01-01

    The work performed under Contracts NAS3-23929 and NAS3-24633 is presented. MTI evaluated the feasibility of high-speed balancing for both the T700 power turbine rotor and the compressor rotor. Modifications were designed for the existing Corpus Christi Army Depot (CCAD) T53/T55 high-speed balancing system for balancing T700 power turbine rotors. Tests conducted under these contracts included a high-speed balancing evaluation for T700 power turbines in the Army/NASA drivetrain facility at MTI. The high-speed balancing tests demonstrated the reduction of vibration amplitudes at operating speed for both low-speed balanced and non-low-speed balanced T700 power turbines. In addition, vibration data from acceptance tests of T53, T55, and T700 engines were analyzed and a vibration diagnostic procedure developed.

  13. High Speed Link Radiated Emission Reduction

    NASA Astrophysics Data System (ADS)

    Bisognin, P.; Pelissou, P.; Cissou, R.; Giniaux, M.; Vargas, O.

    2016-05-01

    To control the radiated emission of high-speed link and associated unit, the current approach is to implement overall harness shielding on cables bundles. This method is very efficient in the HF/ VHF (high frequency/ very high frequency) and UHF (ultra-high frequency) ranges when the overall harness shielding is properly bonded on EMC back-shell. Unfortunately, with the increasing frequency, the associated half wavelength matches with the size of Sub-D connector that is the case for the L band. Therefore, the unit connectors become the main source of interference emission. For the L-band and S-band, the current technology of EMC back-shell leaves thin aperture matched with the L band half wavelength and therefore, the shielding effectiveness is drastically reduced. In addition, overall harness shielding means significant increases of the harness mass.Airbus D&S Toulouse and Elancourt investigated a new solution to avoid the need of overall harness shielding. The objective is to procure EM (Electro-Magnetic) clean unit connected to cables bundles free of any overall harness shielding. The proposed solution is to implement EMC common mode filtering on signal interfaces directly on unit PCB as close as possible the unit connector.Airbus D&S Elancourt designed and manufactured eight mock-ups of LVDS (Low Voltage Differential Signaling) interface PCBs' with different solutions of filtering. After verification of the signal integrity, three mock-ups were retained (RC filter and two common mode choke coil) in addition to the reference one (without EMC filter).Airbus D&S Toulouse manufactured associated LVDS cable bundles and integrated the RX (Receiver) and TX (Transmitter) LVDS boards in shielded boxes.Then Airbus D&S performed radiated emission measurement of the LVDS links subassemblies (e.g. RX and TX boxes linked by LVDS cables) according to the standard test method. This paper presents the different tested solutions and main conclusions on the feasibility of such

  14. Studies of high energy phenomena using muons. [Northern Illinois Univ

    SciTech Connect

    Hedin, D.; Kaplan, D.; Green, J.

    1993-02-01

    The NIU high energy physics group has three main efforts. The first is the D0 experiment at the Fermilab proton-antiproton collider, with major emphasis on its muon system. The second is the involvement of a portion of the group in Fermilab Experiment 789. Finally, members of the group participate in the SDC collaboration at the SSC.

  15. Collision phenomena involving highly-charged ions in astronomical objects

    NASA Technical Reports Server (NTRS)

    Chutjian, A.

    2001-01-01

    A description of the role of highly charged ions in various astronomical objects; includes the use of critical quantities such as cross sections for excitation, charge-exchange, X-ray emission, radiative recombination (RR) and dielectronic recombination (DR); and lifetimes, branching ratios, and A-values.

  16. High Speed, High Accuracy Stage for Advanced Lithography. Phase I

    DTIC Science & Technology

    2007-11-02

    noise and 5nm LSB of our laser interferometer. Zerodur Mounting bar Base expended in this direction Sensor heads Interferometer mirror ...state of the art. Their CORE machine claims an accuracy of 80nm over a 6- inch square field. This machine uses high-speed mirrors to scan multiple...variety of optical paths. If the laboratory is not quiet (e.g. if the interferometer mirror is moving, or if people are talking in the laboratory

  17. Study on the Striation of an Atmospheric Pressure Plasma Flare Using a High Speed Camera

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yutaka; Sakakita, Hajime; Yamada, Hiromasa; Itagaki, Hirotomo; Kiyama, Satoru; Fujiwara, Masanori; Ikehara, Yuzuru; Kim, Jaeho

    2015-09-01

    Characteristics of a low energy atmospheric pressure plasma (LEAPP) specially designed for a medical application has been studied by the visualization of plasma emissions using a high speed camera. The formation of striations in the LEAPP was observed between a nozzle exit and a target material. This result indicates that the plasma propagation is not a bullet type. Detail structure of the striation phenomena will be presented in the conference.

  18. Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

    NASA Technical Reports Server (NTRS)

    Ackeret, J.; Feldmann, F.; Rott, N.

    1947-01-01

    The mutual influences of compression shocks and friction boundary layers were investigated by means of high speed wind tunnels.Schlieren optics provided a clear picture of the flow phenomena and were used for determining the location of the compression shocks, measurement of shock angles, and also for Mach angles. Pressure measurement and humidity measurements were also taken into consideration.Results along with a mathematical model are described.

  19. High speed flow cytometric separation of viable cells

    DOEpatents

    Sasaki, Dennis T.; Van den Engh, Gerrit J.; Buckie, Anne-Marie

    1995-01-01

    Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

  20. High speed flow cytometric separation of viable cells

    DOEpatents

    Sasaki, D.T.; Van den Engh, G.J.; Buckie, A.M.

    1995-11-14

    Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

  1. Wave phenomena in a high Reynolds number compressible boundary layer

    NASA Technical Reports Server (NTRS)

    Bayliss, A.; Maestrello, L.; Parikh, P.; Turkel, E.

    1985-01-01

    Growth of unstable disturbances in a high Reynolds number compressible boundary layer is numerically simulated. Localized periodic surface heating and cooling as a means of active control of these disturbances is studied. It is shown that compressibility in itself stabilizes the flow but at a lower Mach number, significant nonlinear distortions are produced. Phase cancellation is shown to be an effective mechanism for active boundary layer control.

  2. Studies of high energy phenomena using muons. Final progress report

    SciTech Connect

    Hedin, D.; Kaplan, D.; Green, J.

    1993-05-01

    This report covers the activities of the NIU high energy physics group as supported by DOE contract AC02-87ER40368 during the period from July of 1990 to June of 1991 and from February to March 1992. Our group has three main efforts which will be discussed in this paper. The first is the D0 experiment at the Fermilab proton-antiproton collider, with major emphasis on its muon system. The second is the involvement of a portion of the group in Fermilab Experiment 789 which involved detection of meson decays. Finally, we discuss our work with the SDC collaboration at the SSC.

  3. Wave phenomena in a high Reynolds number compressible boundary layer

    NASA Technical Reports Server (NTRS)

    Bayliss, A.; Maestrello, L.; Parikh, P.; Turkel, E.

    1987-01-01

    The behavior of spatially unstable waves in a high Reynolds number compressible laminar boundary layer is investigated by solution of the laminar two-dimensional compressible Navier-Stokes equations (solved to fourth-order accuracy) over a flat plate with a fluctuating disturbance generated at the inflow. A significant nonlinear distortion is produced, in qualitative agreement with experimental data. It is shown that increasing compressibility can significantly stabilize the flow over a flat plate, and that the mechanism of phase cancellation is a viable mechanism for the control of growing disturbances.

  4. Novel High Transverse Momentum Phenomena in Hadronic and Nuclear Collisions

    SciTech Connect

    Brodsky, Stanley J.; /SLAC

    2009-04-10

    I discuss a number of novel phenomenological features of QCD in high transverse momentum reactions. The presence of direct higher-twist processes, where a proton is produced directly in the hard subprocess, can explain the 'baryon anomaly' - the large proton-to-pion ratio seen at RHIC in high centrality heavy ion collisions. Direct hadronic processes can also account for the deviation from leading-twist PQCD scaling at fixed x{sub T} = 2 p{sub T}/{radical}s. I suggest that the 'ridge' --the same-side long-range rapidity correlation observed at RHIC in high centrality heavy ion collisions is due to the imprint of semihard DGLAP gluon radiation from initial-state partons which have transverse momenta biased toward the trigger. A model for early thermalization of the quark-gluon medium is also outlined. Rescattering interactions from gluon-exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam-Tung relation in Drell-Yan reactions, nuclear shadowing--all leading-twist dynamics not incorporated in the light-front wavefunctions of the target computed in isolation. Anti shadowing is shown to be quark flavor specific and thus different in charged and neutral deep inelastic lepton-nucleus scattering. I also discuss other aspects of quantum effects in heavy ion collisions, such as tests of hidden color in nuclear wavefunctions, the use of diffraction to materialize the Fock states of a hadronic projectile and test QCD color transparency, and the important consequences of color-octet intrinsic heavy quark distributions in the proton for particle and Higgs production at high x{sub F}. I also discuss how the AdS/CFT correspondence between Anti-de Sitter space and conformal gauge theories allows one to compute the analytic form of frame-independent light-front wavefunctions of

  5. High-speed line scanning confocal microscope for biological imaging

    NASA Astrophysics Data System (ADS)

    Jung, Seung-Hwan; Kim, Chang-Keun; Ju, Sung-Bin; Cho, Yong-Jin; Jeong, Hyun-Woo; Kim, Beop-Min

    2007-02-01

    We constructed a high-speed laser line-scanning confocal microscope (LSCM) using He-Ne laser (633 nm), a line CCD camera, and an acousto-optic deflector (AOD). The line scanner consists of an AOD and a cylindrical lens, which create a line focus sweeping over the sample. The line scanner generates two-dimensional confocal images (512× 512 pixel image) up to 191 frames per second with no mechanically-moving parts. This system is configured as an inverted microscope for imaging biological organisms or tissues. Images of various biological samples were obtained including rabbit cornea, onion cells, mouse melanoma tumor cells (B16BL6), and human breast tumor cells (BT-20). The frame rate may be further improved up to over 700 frames per second when the image size is reduced (512×128 pixel image). This system may be useful for analyzing fast phenomena during biological and chemical interactions and for imaging 3D structures rapidly.

  6. Measurements of speed of response of high-speed visible and IR optical detectors

    NASA Technical Reports Server (NTRS)

    Rowe, H. E.; Osmundson, J. S.

    1972-01-01

    A technique for measuring speed of response of high speed visible and IR optical detectors to mode-locked Nd:YAG laser pulses is described. Results of measurements of response times of four detectors are presented. Three detectors that can be used as receivers in a 500-MHz optical communication system are tested.

  7. Chicago-St. Louis high speed rail plan

    SciTech Connect

    Stead, M.E.

    1994-12-31

    The Illinois Department of Transportation (IDOT), in cooperation with Amtrak, undertook the Chicago-St. Louis High Speed Rail Financial and Implementation Plan study in order to develop a realistic and achievable blueprint for implementation of high speed rail in the Chicago-St. Louis corridor. This report presents a summary of the Price Waterhouse Project Team`s analysis and the Financial and Implementation Plan for implementing high speed rail service in the Chicago-St. Louis corridor.

  8. Water Containment Systems for Testing High-Speed Flywheels

    NASA Technical Reports Server (NTRS)

    Trase, Larry; Thompson, Dennis

    2006-01-01

    Water-filled containers are used as building blocks in a new generation of containment systems for testing high-speed flywheels. Such containment systems are needed to ensure safety by trapping high-speed debris in the event of centrifugal breakup or bearing failure. Traditional containment systems for testing flywheels consist mainly of thick steel rings. The effectiveness of this approach to shielding against high-speed debris was demonstrated in a series of tests.

  9. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

  10. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

  11. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

  12. Phenomena Elucidation of High Brightness Fiber Laser Welding of Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kawahito, Yousuke; Mizutani, Masami; Katayama, Seiji

    A high-brigthness fiber laser can produce an ultra-high peak power density of MW/mm2 level corresponding to a focused electron beam, and is promising as one of the desirable heat sources for deep-penetration welding. The objectives of this research are to elucidate the factors affecting weld penetration and defects formation mechanisms, to obtain a fundamental knowledge of interaction between a fiber laser beam and the laser-induced plume, and to assess laser absorption with water-calorimetric method in bead-on-plate welding of Type 304 austenitic stainless steel plates with a 10 kW fiber laser beam. Concerning the weldablity and defects, the penetration depth reached 18 mm at the maximum. At 50 mm/s or lower welding speeds, porosity was generated under the conventionally-focused and tightly-focused conditions. X-ray transmission in-site observation images demonstrated that pores were formed not only at the tip of the keyhole but also near the upper part. The keyhole behavior was stabilized by using nitrogen shielding gas, which led to the porosity prevention. As for the interaction under the normal Ar shielding gas conditions, the temperature and ionization degree of the laser-induced plumes were calculated to be 6,000 K and 0.02, respectively, by the Bolzman plots and Saha's equation. It was also found that the attenuation and the refraction between the 10-kW fiber laser beam and the short weakly-ionized plume were too small to exert the reduction in weld penetration. The laser absorption of the stainless steel plate was approximately 85 % high at 10 kW laser power and 50 mm/s welding speed. Compared X-ray transmission observation images of the keyhole with the focusing feature of the fiber laser beam, most of the incident laser passed through the keyhole inlet, and the center part of the beam was delivered directly to the tip of the deep keyhole. Consequently, as far as the adquate welding procedures were utilized on the basis of eclucidation of the welding

  13. High-frequency phenomena in magnetic recording and inductive devices

    NASA Astrophysics Data System (ADS)

    Jury, Jason Charles

    At high frequencies (>1 GHz), ferromagnetic materials and associated electronic circuitry show interesting and sometimes undesirable behavior. In this dissertation, we examine high-frequency effects in magnetic recording and magnetic inductive devices. We analyze "impedance profiling" of the disk drive interconnect, as a way of shaping the write current waveform. This proves to be useful under somewhat limited conditions (for write head with low impedance, characteristic time of the shaped waveform less than the one-way interconnect propagation delay). We then analyze a buffer amplifier (consisting of a single transistor in an emitter-follower configuration) as a means of improving the electronic signal to noise ratio (SNR) associated with high-resistance read sensors. We develop and utilize a "matched filter bound" SNR for assessing the performance of the disk drive read-path. For a hypothetical recording system at an areal density of 1 terabit/in2, the buffer amplifier improves SNR anywhere from 0.5 dB for 670 Mb/s up to 1 dB for 4.17 Gb/s. We then present measurements and quantitative analysis for magnetic fluctuation noise in read sensors. The analysis is enabled by rigorous calibration of the noise measurement setup. We are able to explain the behavior of the mag-noise (primary) resonance frequency versus bias current and externally-applied field, by using a micromagnetic model (NIST-OOMMF) where we also account for sensor heating and associated reduction in free-layer and biasing magnet saturation moment. We then analyze the behavior of multi-domain magnetic materials and the associated inductive device behaviors. First we utilize micromagnetic modeling to calculate the spin-resonance modes associated with multi-domain films. We find agreement in trend between the modeling results and experimentally-observed sub-FMR permeability resonances, particularly that both model and experiment predict a power-law dependence of frequency on the ratio of thickness to

  14. Anomolous Fatigue Crack Growth Phenomena in High-Strength Steel

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; James, Mark A.; Johnston, William M., Jr.; Newman, James C., Jr.

    2004-01-01

    The growth of a fatigue crack through a material is the result of a complex interaction between the applied loading, component geometry, three-dimensional constraint, load history, environment, material microstructure and several other factors. Previous studies have developed experimental and computational methods to relate the fatigue crack growth rate to many of the above conditions, with the intent of discovering some fundamental material response, i.e. crack growth rate as a function of something. Currently, the technical community uses the stress intensity factor solution as a simplistic means to relate fatigue crack growth rate to loading, geometry and all other variables. The stress intensity factor solution is a very simple linear-elastic representation of the continuum mechanics portion of crack growth. In this paper, the authors present fatigue crack growth rate data for two different high strength steel alloys generated using standard methods. The steels exhibit behaviour that appears unexplainable, compared to an aluminium alloy presented as a baseline for comparison, using the stress intensity factor solution.

  15. High-speed phase-shifting interferometry using triangular prism for time-resolved temperature measurement.

    PubMed

    Shoji, Eita; Komiya, Atsuki; Okajima, Junnosuke; Kawamura, Hiroshi; Maruyama, Shigenao

    2015-07-10

    This study proposes a high-speed phase-shifting interferometer with an original optical prism. This phase-shifting interferometer consists of a polarizing Mach-Zehnder interferometer, an original optical prism, a high-speed camera, and an image-processing unit for a three-step phase-shifting technique. The key aspect of the application of the phase-shifting technique to high-speed experiments is an original prism, which is designed and developed specifically for a high-speed phase-shifting technique. The arbaa prism splits an incident beam into four output beams with different information. The interferometer was applied for quantitative visualization of transient heat transfer. In order to test the optical system for measuring high-speed phenomena, the temperature during heat conduction was measured around a heated thin tungsten wire (diameter of 5 μm) in water. The visualization area is approximately 90  μm×210  μm, and the spatial resolution is 3.5 μm at 300,000 fps of the maximum temporal resolution with a high-speed camera. The temperature fields around the heated wire were determined by converting phase-shifted data using the inverse Abel transform. Finally, the measured temperature distribution was compared with numerical calculations to validate the proposed system; a good agreement was obtained.

  16. Studies of high energy phenomena using muons. Final report

    SciTech Connect

    1995-12-31

    This report covers the activities of the NIU high energy physics group as supported by DOE contract DE-FG02-91ER40641.A000 during the period from 1992 to 1995, and is the final report for this award. The group had three main efforts. The first was the D0 experiment at the Fermilab proton-antiproton collider, with major emphasis on its muon system. The second is the involvement of a portion of the group in Fermilab Experiment 789. Finally, the authors were members of the SDC collaboration at the SSC. The group consisted of four faculty members, three research associates, and undergraduate and graduate students. The D0 experiment at Fermilab is one of two (the other is CDF) general purpose experiments operating at the Tevatron proton-antiproton collider. Starting in the Fall of 1992, the first data collection occurred at D0. Physics publications are tabulated in the Appendix, with the discovery of the top quark in 1995 being the most prominent. Members of the NIU group worked on a variety of physics topics: Hedin on B-physics and the top-quark search, Fortner on Drell-Yan and other QCD topics, Green on di-Boson production, and Markeloff on excited-quark states. Hedin was also co-coordinator of the B-physics group during this period. The primary emphasis of the NIU D0 group was the muon system. NIU had particular responsibilities for data acquisition; chamber calibration; the Level-2 trigger; and the reconstruction. Hedin also was coordinator of muon software and had the responsibility for muon identification. Work on these items is summarized in a series of D0 Notes listed in the Appendix. Willis, Sirotenko, Hedin and Fortener were also members of the SDC collaboration at the SSC. NIU was a key participant in the calculation of low-energy neutron and photon backgrounds in the SDC experiment, and in designing shielding for the proposed muon system.

  17. NETL Extreme Drilling Laboratory Studies High Pressure High Temperature Drilling Phenomena

    SciTech Connect

    Lyons, K.D.; Honeygan, S.; Moroz, T

    2007-06-01

    The U.S. Department of Energy’s National Energy Technology Laboratory (NETL) established an Extreme Drilling Lab to engineer effective and efficient drilling technologies viable at depths greater than 20,000 feet. This paper details the challenges of ultra-deep drilling, documents reports of decreased drilling rates as a result of increasing fluid pressure and temperature, and describes NETL’s Research and Development activities. NETL is invested in laboratory-scale physical simulation. Their physical simulator will have capability of circulating drilling fluids at 30,000 psi and 480 °F around a single drill cutter. This simulator will not yet be operational by the planned conference dates; therefore, the results will be limited to identification of leading hypotheses of drilling phenomena and NETL’s test plans to validate or refute such theories. Of particular interest to the Extreme Drilling Lab’s studies are the combinatorial effects of drilling fluid pressure, drilling fluid properties, rock properties, pore pressure, and drilling parameters, such as cutter rotational speed, weight on bit, and hydraulics associated with drilling fluid introduction to the rock-cutter interface. A detailed discussion of how each variable is controlled in a laboratory setting will be part of the conference paper and presentation.

  18. NETL Extreme Drilling Laboratory Studies High Pressure High Temperature Drilling Phenomena

    SciTech Connect

    Lyons, K.D.; Honeygan, S.; Moroz, T.H.

    2008-12-01

    The U.S. Department of Energy's National Energy Technology Laboratory (NETL) established the Extreme Drilling Laboratory to engineer effective and efficient drilling technologies viable at depths greater than 20,000 ft. This paper details the challenges of ultradeep drilling, documents reports of decreased drilling rates as a result of increasing fluid pressure and temperature, and describes NETL's research and development activities. NETL is invested in laboratory-scale physical simulation. Its physical simulator will have capability of circulating drilling fluids at 30,000 psi and 480°F around a single drill cutter. This simulator is not yet operational; therefore, the results will be limited to the identification of leading hypotheses of drilling phenomena and NETL's test plans to validate or refute such theories. Of particular interest to the Extreme Drilling Laboratory's studies are the combinatorial effects of drilling fluid pressure, drilling fluid properties, rock properties, pore pressure, and drilling parameters, such as cutter rotational speed, weight on bit, and hydraulics associated with drilling fluid introduction to the rock-cutter interface. A detailed discussion of how each variable is controlled in a laboratory setting will be part of the conference paper and presentation.

  19. High-speed dual Langmuir probe.

    PubMed

    Lobbia, Robert B; Gallimore, Alec D

    2010-07-01

    In an effort to temporally resolve the electron density, electron temperature, and plasma potential for turbulent plasma discharges, a unique high-speed dual Langmuir probe (HDLP) has been developed. A traditional single Langmuir probe of cylindrical geometry (exposed to the plasma) is swept simultaneously with a nearby capacitance and noise compensating null probe (fully insulated from the plasma) to enable bias sweep rates on a microsecond timescale. Traditional thin-sheath Langmuir probe theory is applied for interpretation of the collected probe data. Data at a sweep rate of 100 kHz are presented; however the developed system is capable of running at 1 MHz-near the upper limit of the applied electrostatic Langmuir probe theory for the investigated plasma conditions. Large sets (100,000 sweeps at each of 352 spatial locations) of contiguous turbulent plasma properties are collected using simple electronics for probe bias driving and current measurement attaining 80 dB signal-to-noise measurements with dc to 1 MHz bandwidth. Near- and far-field plume measurements with the HDLP system are performed downstream from a modern Hall effect thruster where the time-averaged plasma properties exhibit the approximate ranges: electron density n(e) from (1x10(15))-(5x10(16)) m(-3), electron temperature T(e) from 1 to 3.5 eV, and plasma potential V(p) from 5 to 15 V. The thruster discharge of 200 V (constant anode potential) and 2 A (average discharge current) displays strong, 2.2 A peak-to-peak, current oscillations at 19 kHz, characteristic of the thruster "breathing mode" ionization instability. Large amplitude discharge current fluctuations are typical for most Hall thrusters, yet the HDLP system reveals the presence of the same 19 kHz fluctuations in n(e)(t), T(e)(t), and V(p)(t) throughout the entire plume with peak-to-peak divided by mean plasma properties that average 94%. The propagation delays between the discharge current fluctuations and the corresponding plasma

  20. High speed data transmission for the SSC solenoidal detector

    NASA Astrophysics Data System (ADS)

    Leskovar, B.

    1991-04-01

    High speed data transmission using fiber optics for the Superconducting Super Collider solenoidal detector has been studied. The solenoidal detector system will consist of nine subsystems involving more than a total 10(exp 7) channels of readout electronics. Consequently, a new high performance data acquisition system, incorporating high-speed optical fiber networks, will be required to process this large quantity of data.

  1. Numerical and experimental investigation of wave dynamic processes in high-speed train/tunnels

    NASA Astrophysics Data System (ADS)

    Zonglin, Jiang; Matsuoka, K.; Sasoh, A.; Takayama, K.

    2002-06-01

    Numerical and experimental investigation on wave dynamic processes induced by high-speed trains entering railway tunnels are presented. Experiments were conducted by using a 1:250 scaled train-tunnel simulator. Numerical simulations were carried out by solving the axisymmetric Euler equations with the dispersion-controlled scheme implemented with moving boundary conditions. Pressure histories at various positions inside the train-tunnel simulator at different distance measured from the entrance of the simulator are recorded both numerically and experimentally, and then compared with each other for two train speeds. After the validation of nonlinear wave phenomena, detailed numerical simulations were then conducted to account for the generation of compression waves near the entrance, the propagation of these waves along the train tunnel, and their gradual development into a weak shock wave. Four wave dynamic processes observed are interpreted by combining numerical results with experiments. They are: high-speed trains moving over a free terrain before entering railway tunnels; the abrupt-entering of high-speed trains into railway tunnels; the abrupt-entering of the tail of high-speed trains into railway tunnels; and the interaction of compression and expansion waves ahead of high-speed trains. The effects of train-tunnel configuration, such as the train length and the train-tunnel blockage ratio, on these wave processes have been investigated as well.

  2. Time optimal paths for high speed maneuvering

    SciTech Connect

    Reister, D.B.; Lenhart, S.M.

    1993-01-01

    Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

  3. Sand Behavior Induced by High-Speed Penetration of Projectile. Phenomenological studies of the response of granular and geological media to high-speed (Mach 1-5) projectiles

    DTIC Science & Technology

    2011-02-07

    Sand Behavior Induced by High-Speed Penetration of Projectile Keiko Watanabe*, Koichi Tanaka**, Keisuke Iwane*, Syungo Fukuma*, Kazuyoshi...phenomena, which were the behavior of ejecta and projectile , the penetration depth and speed of projectile , fractured grains and the pressure...are summarized as follows: Sands around the penetrated projectile were smashed to fine powder of 5 µm or less like a potato starch. Circumferential

  4. High-speed optical 3D sensing and its applications

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshihiro

    2016-12-01

    This paper reviews high-speed optical 3D sensing technologies for obtaining the 3D shape of a target using a camera. The focusing speed is from 100 to 1000 fps, exceeding normal camera frame rates, which are typically 30 fps. In particular, contactless, active, and real-time systems are introduced. Also, three example applications of this type of sensing technology are introduced, including surface reconstruction from time-sequential depth images, high-speed 3D user interaction, and high-speed digital archiving.

  5. High-speed ground transportation: some current and future alternatives

    SciTech Connect

    Morita, T.

    1984-01-01

    High-speed ground transportation (HSGT), the value of time, and the social and technological considerations of inter-city transportation are discussed in this article. A particularly promising mode of high-speed ground transportation (MAGLEV) is discussed in some detail. An average speed for HSGT service, 400 kilometers per hour, seems to be attainable. In conclusion, the proposal for a hypersonic subway will be analyzed. 2 figures, 1 table.

  6. Kevlar Properties Investigation High Speed Abrasion Resistance

    DTIC Science & Technology

    1980-02-01

    leading edge of the warp knuckle . These fibers were obviously flattened and smeared at the tips due to abrasion. The lack of severe cracking and...Parallel Configuration at a Speed of 160 fps Using a Contact Force of 15 Lb and a Contact Time of 30 Seconds 68 Photographs of Scorched Knuckle and...of filaments were protruding from the yarn knuckles giving the yarn an open appearance. Figure 4B shows photographs of the piled and unpiled surfaces

  7. High Speed Cascadable Signal Processing Circuits

    DTIC Science & Technology

    1988-04-29

    Mexico 88002 / "’ . Otavio J. Morales . Assistant Principal Investigator ~, . - .-" " The views, opinions, and/or findings contained in this report...T Fort Collins, Colorado 80525 U.S.Army White Sands Missile Ranpe New Mexico 88002-91h3 go. NAME OF FUNDING i SPONSOXINd 9b. OFFICE SYMBOL 9...general purpos; data processor. The Vector Processing Hardware ( VPH ) is a speed-optimized architecture capable of processing vectors of complex data. The

  8. High loading, low speed fan study, 5

    NASA Technical Reports Server (NTRS)

    Keenan, M. J.; Burdsall, E. A.

    1973-01-01

    A low speed, low noise, single stage fan was designed and tested. Design pressure ratio was 1.5 at a rotor tip speed of 1000 ft/sec. No inlet guide vane was used, the rotor stator was spaced and the number of rotor and stator airfoils was selected for low noise. Tests were conducted with uniform and distorted inlet flows. Stall margin of the initial design was too low for practical application. Airfoil slots and boundary layer and endwall devices did not improve stall margin sufficiently. A redesigned stator with reduced loadings increased stall margin, giving a fan efficiency of 0.883, 15% stall margin, and a 1.474 pressure radio at a specific flow of 41.7 lb/sec sq ft. Casing treatment over rotor tips improved stall margin with distorted inlet flow; vortex generators did not. Blade passing frequency noise increased with rotor relative Mach number. No supersonic fan noise was measured below 105% of design speed. Slotting airfoils, casing treatments, and a reduction of the ratio (number-stators/number-rotors) from (2n + 16) to (2n + 2) had no significant effects on noise.

  9. High-speed optical correlator with coaxial holographic system

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Watanabe, Eriko

    2015-09-01

    A high-speed volume holographic optical correlator is developed, which takes advantage of a coaxial holographic system. We have realized this high-speed correlator using an optimal design of the signal pattern, which improves the shift multiplex recording shift pitch. The speed of this correlator was further improved by increasing the number of pixels in the spatial light modulator and using a high speed rotating actuator. This correlation system successfully achieved an equal error rate of 0% by performing optical correlation over 900 times. It also achieved optical correlation experiment, at a shift pitch of 2.45 µm and a disk rotation speed of 900 rpm. In terms of optical correlation calculation speed, it yielded a peak interval of 542 ns, which corresponds to 1.846 × 106 frames per second.

  10. Structural vulnerability and intervention of high speed railway networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Hu, Funian; Wang, Shuliang; Dai, Yang; Wang, Yixing

    2016-11-01

    This paper employs complex network theory to assess the structural vulnerability of high speed railway networks subjected to two different malicious attacks. Chinese, US and Japanese high speed railway networks are used to discuss the vulnerable characteristics of systems. We find that high speed railway networks are very fragile when suffering serious disturbances and two attack rules can cause analogous damages to one high speed railway network, which illustrates that the station with large degree possesses high betweenness, vice versa. Meanwhile, we discover that Japanese high speed railway network has the best global connectivity, but Chinese high speed railway network has the best local connectivity and possesses the largest transport capacity. Moreover, we find that there exist several redundant paths in Chinese high speed railway network and discover the critical stations of three HSRNs. Furthermore, the nearest-link method is adopted to implement topological interventions and to improve the connectivity and reliability of high speed railway networks. In addition, the feasibility and effectiveness of topological interventions are shown by simulations.

  11. High-speed wireless optical LANs

    NASA Astrophysics Data System (ADS)

    Oe, Kunishige; Sato, Syuichi; Okayama, Motoyuki; Kubota, Toshihiro

    2001-11-01

    Study on high speed indoor wireless optical LAN system enabling 100Mbps signal transmission with low bit error rate (10-9) is presented. To realize the optical LAN system handling 100 Mbps signal, a directed line of sight (LOS) system is adopted as the optical receiver sensitivity for a bit error rate of 10-9 for 100 Mbps signals is fairly large. In the system, new approaches are introduced: WDM technology which enables bi-directional transmission in full duplex manner is applied using a 1.3 micrometers laser diode for down-link and 0.65 micrometers red laser diode for up-link light sources. As the wavelengths of the two lasers are quite separated from each other, this WDM technology brings an advantage that two kind of semiconductor materials can be used for detectors; GaInAs is used for down-link while Si is applied for up-link. GaInAs PD cannot detect the up-link laser light of 0.65 micrometers and Si PD or APD cannot detect the down-link laser light of 1.3micrometers . Therefore full duplex transmission can be achieved in this configuration. In the indoor wireless optical LAN system, one of the critical points is the transmitter configuration for down- link which enables to deliver optical power enough for 100 Mbps transmission to user areas as wide as possible with inexpensive prices. To realize the point, a special 1.3micrometers laser diode, a spot-size converter integrated laser (SS-LD), is introduced in company with convex lens and an object lens to deliver optical power to areas as wide as possible. As the far-field patterns of the SS-LD are fairly narrow, most of the output power of the LD could be collected to and spread wide by the object lens of 40 magnifications. Using the device, 3m diameter circle area in the plane 2m apart from the 1.3micrometers SS-LD emitting 20 mW optical power, could receive optical power above the receiver sensitivity for a bit error rate of 10-9 for 100 Mbps signals. The visible red light is convenient for not only position

  12. High-resolution high-speed panoramic cardiac imaging system

    PubMed Central

    Evertson (In Memoriam), Dale W.; Holcomb, Mark R.; Eames, Matthew D.C.; Bray, Mark-Anthony P.; Sidorov, Veniamin Y.; Xu, Junkai; Wingard, Holley; Dobrovolny, Hana M.; Woods, Marcella C.; Gauthier, Daniel J.; Wikswo, John P.

    2008-01-01

    A panoramic cardiac imaging system consisting of three high-speed CCD cameras has been developed to image the surface electrophysiology of a rabbit heart via fluorescence imaging using a voltage-sensitive fluorescent dye. A robust, unique mechanical system was designed to accommodate the three cameras and to adapt to the requirements of future experiments. A unified computer interface was created for this application – a single workstation controls all three CCD cameras, illumination, and stimulation, and the stepping motor rotates the heart. The geometric reconstruction algorithms were adapted from a previous cardiac imaging system. We demonstrate the system by imaging a polymorphic cardiac tachycardia. PMID:18334422

  13. The Advantages of ISDN for High-Speed Remote Access.

    ERIC Educational Resources Information Center

    Galvin, Mark; Hauf, Al

    1997-01-01

    Explains why ISDN (integrated services digital network) is the most practical solution for high-speed remote access, including reliability, cost, flexibility, scaleability, standards, and manageability. Other data transmission options are discussed, including asymmetric digital subscriber lines (ADSL), high-speed digital subscriber lines (HDSL),…

  14. HIGH-SPEED GC/MS FOR AIR ANALYSIS

    EPA Science Inventory

    High speed or fast gas chromatography (FGC) consists of narrow bandwidth injection into a high-speed carrier gas stream passing through a short column leading to a fast detector. Many attempts have been made to demonstrate FGC, but until recently no practical method for routin...

  15. Seakeeping Analysis of Small Displacement High-Speed Vessels

    DTIC Science & Technology

    2003-03-01

    72 73 74 75 76 77 78 79 80 81 82 83 VI. LIST OF REFERENCES [1] Kennell, Colen. Design ... trends in High-Speed Transport. Marine Technology, Vol. 35, No. 3, July 1998, pp.127-134. [2] Ritter, Owen K., Templeman, Michael T. High-Speed

  16. HIGH-SPEED GC/MS FOR AIR ANALYSIS

    EPA Science Inventory

    High speed or fast gas chromatography (FGC) consists of narrow bandwidth injection into a high-speed carrier gas stream passing through a short column leading to a fast detector. Many attempts have been made to demonstrate FGC, but until recently no practical method for routin...

  17. High-Speed Video Analysis of Damped Harmonic Motion

    ERIC Educational Resources Information Center

    Poonyawatpornkul, J.; Wattanakasiwich, P.

    2013-01-01

    In this paper, we acquire and analyse high-speed videos of a spring-mass system oscillating in glycerin at different temperatures. Three cases of damped harmonic oscillation are investigated and analysed by using high-speed video at a rate of 120 frames s[superscript -1] and Tracker Video Analysis (Tracker) software. We present empirical data for…

  18. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of the isosceles triangle formed by the side lights and masthead light when seen in end elevation is... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at...

  19. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of the isosceles triangle formed by the side lights and masthead light when seen in end elevation is... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at...

  20. High-Speed Video Analysis of Damped Harmonic Motion

    ERIC Educational Resources Information Center

    Poonyawatpornkul, J.; Wattanakasiwich, P.

    2013-01-01

    In this paper, we acquire and analyse high-speed videos of a spring-mass system oscillating in glycerin at different temperatures. Three cases of damped harmonic oscillation are investigated and analysed by using high-speed video at a rate of 120 frames s[superscript -1] and Tracker Video Analysis (Tracker) software. We present empirical data for…

  1. High Speed Sonar Array Depressor Program

    DTIC Science & Technology

    1981-11-30

    were conducted in the Exuma Sound In August 1981. 33 Report 12482 1000 4000 z 3000 2000 - 500 1000 0 1I 0 0 5 10 15 20 25 30 SPEED-KNOTS 700 1:11 IS z...the ONR Sea Trial 1A6 on the R/V ATHENA. The depressor was deployed during that portion of the trials occuring on 5, 6, 7 and 8 August 1981 in Exuma ...Before the Exuma Sound runs the bolt holes in tVe depressor were permanently plugged and faired. From then on no relation was seen between the sign

  2. Spontaneous sidebanding in high speed rotordynamics

    NASA Astrophysics Data System (ADS)

    Ehrich, F. F.

    1992-10-01

    It is noted that the spontaneous sideband spacing frequency seems to be a whole number fraction (1/J) of the operating speed which indicates that the wave form is periodic and completes a full cycle every J rotations of the rotor. Employing a numerical model of a rotor that simulates local contact with a stator in close proximity as a bilinear spring, studies have been conducted to explore the circumstances for this spontaneous sidebanding. Two general classes of this type of response are determined in a system that is effectively single-degree-of-freedom.

  3. High speed all-optical networks

    NASA Technical Reports Server (NTRS)

    Chlamtac, Imrich

    1993-01-01

    An inherent problem of conventional point-to-point WAN architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. This report presents the first solution to WDM based WAN networks that overcomes this limitation. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs.

  4. Spin-current phenomena at high magnetic fields and high temperatures

    NASA Astrophysics Data System (ADS)

    Uchida, Ken-Ichi

    In the field of spintronics, many experimental and theoretical studies have been focused on spin-transport phenomena in paramagnet/ferromagnet junction systems, where a spin current plays a central role. After the first demonstration of spin transport in insulator-based systems, a Pt/YIG junction system becomes one of the prototype samples. In this system, itinerant spins in Pt and localized magnetic moments in YIG interact with each other via the interface s-d interaction, i.e., the spin-mixing conductance; this interaction is the basic mechanism underlying various spin-current-related phenomena, such as the spin pumping, the spin Seebeck effect, and the recently-discovered spin Hall magnetoresistance (SMR). In this talk, we report the observation of the longitudinal spin Seebeck effect (LSSE) and the SMR in Pt/YIG systems at high magnetic fields and high temperatures. The LSSE measurements in a high magnetic field range confirm that the observed voltage in the Pt/YIG systems is of magnon origin, providing a useful way to distinguish the LSSE from the anomalous Nernst effect induced by proximity ferromagnetism in Pt. The LSSE and SMR at high temperatures highlight the importance of the temperature dependence of the spin-mixing conductance at the Pt/YIG interface. These results will be helpful for obtaining full understanding of the mechanism of the LSSE and SMR. We thank E. Saitoh, S. Maekawa, G. E. W. Bauer, H. Adachi, Y. Ohnuma, T. Kikkawa, S. Daimon, Y. Shiomi, and J. Shiomi for their support and valuable discussions.

  5. New image-capturing techniques for a high-speed motion analyzer

    NASA Astrophysics Data System (ADS)

    Balch, Kris S.

    1991-01-01

    A motion analyzer is used to capture and store high-speed images. Once the images are stored they may be reviewed in slow motion while quantitative measurements can be made for analysis. New techniques for capturing images are now available in a high speed motion analyzer. These new image capturing techniques have opened the technology door for new opportunities and allows the use of motion analysis in ways not feasible before. Current motion analysis design philosophy uses magnetic tape as the storage medium for recording images. The advantages of this medium high density and non-volatility have been used in the SP2000 Motion Analysis System and KODAK EKTAPRO 1000 Motion Analyzer. Based on industrial experience with motion analysis new image capturing techniques have been developed. These new image capturing techniques are well suited for imaging repetitive processes continuous flow processes controlled events uncontrolled events and varying demand events. An important part of these new image capturing techniques is electronic triggering. The electronic trigger is used to detect a physical phenomena unique to the event to be recorded. The phenomena that sets the trigger can be as simple as a flash switch closure sound temperature or a voltage change. Trigger requirements are application specific. Determining the trigger requirements will require innovation and creativity by the user of the motion analyzer. Given a set of detectors and the hardware for interfacing their outputs the user need to determine the setup to detect the phenomena unique to the event recorded. This paper will address the new image capturing techniques and their application to high speed motion analysis. 2 / SPIE Vol. 1346 Ultrahigh- and High-Speed Photography Videography Photonics and Velocimetry ''90

  6. Nonparametric analysis of high wind speed data

    NASA Astrophysics Data System (ADS)

    Francisco-Fernández, Mario; Quintela-del-Río, Alejandro

    2013-01-01

    In this paper, nonparametric curve estimation methods are applied to analyze time series of wind speeds, focusing on the extreme events exceeding a chosen threshold. Classical parametric statistical approaches in this context consist in fitting a generalized Pareto distribution (GPD) to the tail of the empirical cumulative distribution, using maximum likelihood or the method of the moments to estimate the parameters of this distribution. Additionally, confidence intervals are usually computed to assess the uncertainty of the estimates. Nonparametric methods to estimate directly some quantities of interest, such as the probability of exceedance, the quantiles or return levels, or the return periods, are proposed. Moreover, bootstrap techniques are used to develop pointwise and simultaneous confidence intervals for these functions. The proposed models are applied to wind speed data in the Gulf Coast of US, comparing the results with those using the GPD approach, by means of a split-sample test. Results show that nonparametric methods are competitive with respect to the standard GPD approximations. The study is completed generating synthetic data sets and comparing the behavior of the parametric and the nonparametric estimates in this framework.

  7. Kinetic phenomena in organic conductors in high magnetic fields (Review Article)

    NASA Astrophysics Data System (ADS)

    Peschansky, V. G.; Stepanenko, D. I.

    2016-11-01

    A review of experimental and theoretical studies of transport phenomena in strongly anisotropic organic conductors is presented. Considerable attention is paid to the phenomena that are specific to quasi-2D and quasi-1D conductive structures and have no analogues both in ordinary metals and in truly 2D or 1D conducting systems. Angular magnetoresistance oscillations, de Haas-van Alphen and Shubnikov-de Haas phenomena, high-temperature quantum oscillations of the magnetoresistance, and high-frequency resonances, including those arising due to the motion of electrons open trajectories, are discussed. The resonant angular oscillations of high-frequency conductivity and weakly damped electromagnetic waves in quasi-2D organic conductors under strong spatial dispersion are considered.

  8. High-Speed Tests of Radial-Engine Cowlings

    NASA Technical Reports Server (NTRS)

    Robinson, Russell G.; Becker, John V.

    1939-01-01

    The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the N.A.C.A. 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination mere used in the tests.

  9. High-speed OCT light sources and systems [Invited

    PubMed Central

    Klein, Thomas; Huber, Robert

    2017-01-01

    Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems. PMID:28270988

  10. High-Speed Tests of Conventional Radial-Engine Cowlings

    NASA Technical Reports Server (NTRS)

    Robinson, Russell G; Becker, John V

    1942-01-01

    The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the NACA 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination were used in the tests.

  11. A MHz speed wavelength sweeping for ultra-high speed FBG interrogation

    NASA Astrophysics Data System (ADS)

    Kim, Gyeong Hun; Lee, Hwi Don; Eom, Tae Joong; Jeong, Myung Yung; Kim, Chang-Seok

    2015-09-01

    We demonstrated a MHz speed wavelength-swept fiber laser based on the active mode locking (AML) technique and applied to interrogation system of an array of fiber Bragg grating (FBG) sensors. MHz speed wavelength sweeping of wavelength-swept fiber laser can be obtained by programmable frequency modulation of the semiconductor optical amplifier (SOA) without any wavelength tunable filter. Both static and dynamic strain measurement of FBG sensors were successfully characterized with high linearity of an R-square value of 0.9999 at sweeping speed of 50 kHz.

  12. Study of the binding zone of electrical discharge to the liquid cathode by high-speed visualization

    NASA Astrophysics Data System (ADS)

    Tazmeev, G. Kh; Timerkaev, B. A.; Tazmeev, Kh K.

    2017-01-01

    This work is devoted to the experimental study of the properties of the binding zone of gas discharge to the liquid electrolyte cathode. Detailed description of the processes on the border “plasma-liquid” was analysis by of high-speed shooting. Were installed the regularities of phenomena of transfer substance and electric charges from the liquid electrolyte in the plasma column.

  13. Investigation of High-Latitude Phenomena Using Polar Data and Global Simulations

    NASA Technical Reports Server (NTRS)

    Russell, Christopher T.; Hoffman, Robert (Technical Monitor)

    2001-01-01

    The goal of this one-year project was to use data from the Polar satellite in conjunction with global simulations of Earth's magnetosphere to investigate phenomena in the high-latitude magnetosphere. Specifically, we addressed reconnection at the cusp during periods of northward interplanetary magnetic field (IMF), and the effects of substorms on the high-latitude magnetosphere.

  14. High speed demodulation systems for fiber optic grating sensors

    NASA Technical Reports Server (NTRS)

    Udd, Eric (Inventor); Weisshaar, Andreas (Inventor)

    2002-01-01

    Fiber optic grating sensor demodulation systems are described that offer high speed and multiplexing options for both single and multiple parameter fiber optic grating sensors. To attain very high speeds for single parameter fiber grating sensors ratio techniques are used that allow a series of sensors to be placed in a single fiber while retaining high speed capability. These methods can be extended to multiparameter fiber grating sensors. Optimization of speeds can be obtained by minimizing the number of spectral peaks that must be processed and it is shown that two or three spectral peak measurements may in specific multiparameter applications offer comparable or better performance than processing four spectral peaks. Combining the ratio methods with minimization of peak measurements allows very high speed measurement of such important environmental effects as transverse strain and pressure.

  15. Thermomechanical simulations and experimental validation for high speed incremental forming

    NASA Astrophysics Data System (ADS)

    Ambrogio, Giuseppina; Gagliardi, Francesco; Filice, Luigino; Romero, Natalia

    2016-10-01

    Incremental sheet forming (ISF) consists in deforming only a small region of the workspace through a punch driven by a NC machine. The drawback of this process is its slowness. In this study, a high speed variant has been investigated from both numerical and experimental points of view. The aim has been the design of a FEM model able to perform the material behavior during the high speed process by defining a thermomechanical model. An experimental campaign has been performed by a CNC lathe with high speed to test process feasibility. The first results have shown how the material presents the same performance than in conventional speed ISF and, in some cases, better material behavior due to the temperature increment. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process confirming substantially experimental evidence.

  16. Traction contact performance evaluation at high speeds

    NASA Technical Reports Server (NTRS)

    Tevaarwerk, J. L.

    1981-01-01

    The results of traction tests performed on two fluids are presented. These tests covered a pressure range of 1.0 to 2.5 GPa, an inlet temperature range of 30 'C to 70 'C, a speed range of 10 to 80 m/sec, aspect ratios of .5 to 5 and spin from 0 to 2.1 percent. The test results are presented in the form of two dimensionless parameters, the initial traction slope and the maximum traction peak. With the use of a suitable rheological fluid model the actual traction curves measured can now be reconstituted from the two fluid parameters. More importantly, the knowledge of these parameters together with the fluid rheological model, allow the prediction of traction under conditions of spin, slip and any combination thereof. Comparison between theoretically predicted traction under these conditions and those measured in actual traction tests shows that this method gives good results.

  17. Thermometry of a high temperature high speed micro heater.

    PubMed

    Xu, M; Slovin, G; Paramesh, J; Schlesinger, T E; Bain, J A

    2016-02-01

    A high temperature high-speed tungsten micro heater was fabricated and tested for application in phase change switches to indirectly heat and transform phase change material. Time domain transmissometry was used to measure heater temperature transients for given electrical inputs. Finite element modeling results on heater temperature transients show a good consistency between experiments and simulations with 0.2% mismatch in the best case and 13.1% in the worst case. The heater described in this work can reliably reach 1664 K at a rate of 1.67 × 10(10) K/s and quench to room temperature with a thermal RC time constant (time for T to fall by a factor of e) of less than 40 ns.

  18. High-Speed, High-Temperature Finger Seal Test Results

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.; Kumar, Arun; Delgado, Irebert R.

    2002-01-01

    Finger seals have significantly lower leakage rates than conventional labyrinth seals used in gas turbine engines and are expected to decrease specific fuel consumption by over 1 percent and to decrease direct operating cost by over 0.5 percent. Their compliant design accommodates shaft growth and motion due to thermal and dynamic loads with minimal wear. The cost to fabricate these finger seals is estimated to be about half the cost to fabricate brush seals. A finger seal has been tested in NASA's High Temperature, High Speed Turbine Seal Test Rig at operating conditions up to 1200 F, 1200 ft/s, and 75 psid. Static, performance and endurance test results are presented. While seal leakage and wear performance are acceptable, further design improvements are needed to reduce the seal power loss.

  19. Lee-surface heating and flow phenomena on space shuttle orbiters at large angles of attack and hypersonic speeds

    NASA Technical Reports Server (NTRS)

    Hefner, J. N.

    1972-01-01

    The lee-surface flow phenomena on a delta-wing orbiter and a straight-wing orbiter have been investigated at angles of attack between 0 deg and 50 deg at a Mach number of 6. Limited studies of the delta-wing orbiter were conducted at a Mach number of 19. Heat-transfer data, pressure distributions, and oil-flow studies were employed to experimentally examine the nature of the surface flow and the severity of the lee-surface heating. The effects of Reynolds number on the flow field and heating were investigated. Problem areas are defined and areas for further study are recommended.

  20. High speed sampling circuit design for pulse laser ranging

    NASA Astrophysics Data System (ADS)

    Qian, Rui-hai; Gao, Xuan-yi; Zhang, Yan-mei; Li, Huan; Guo, Hai-chao; Guo, Xiao-kang; He, Shi-jie

    2016-10-01

    In recent years, with the rapid development of digital chip, high speed sampling rate analog to digital conversion chip can be used to sample narrow laser pulse echo. Moreover, high speed processor is widely applied to achieve digital laser echo signal processing algorithm. The development of digital chip greatly improved the laser ranging detection accuracy. High speed sampling and processing circuit used in the laser ranging detection system has gradually been a research hotspot. In this paper, a pulse laser echo data logging and digital signal processing circuit system is studied based on the high speed sampling. This circuit consists of two parts: the pulse laser echo data processing circuit and the data transmission circuit. The pulse laser echo data processing circuit includes a laser diode, a laser detector and a high sample rate data logging circuit. The data transmission circuit receives the processed data from the pulse laser echo data processing circuit. The sample data is transmitted to the computer through USB2.0 interface. Finally, a PC interface is designed using C# language, in which the sampling laser pulse echo signal is demonstrated and the processed laser pulse is plotted. Finally, the laser ranging experiment is carried out to test the pulse laser echo data logging and digital signal processing circuit system. The experiment result demonstrates that the laser ranging hardware system achieved high speed data logging, high speed processing and high speed sampling data transmission.

  1. Turbomachinery technology for high-speed civil flight

    NASA Technical Reports Server (NTRS)

    Saunders, Neal T.; Glassman, Arthur J.

    1989-01-01

    NASA Lewis' research and technology efforts applicable to turbomachinery for high-speed flight are discussed. The potential benefits and cycle requirements for advanced variable cycle engines and the supersonic throughflow fan engine for a high-speed civil transport application are presented. The supersonic throughflow fan technology program is discussed. Technology efforts in the basic discipline areas addressing the severe operating conditions associated with high-speed flight turbomachinery are reviewed. Included are examples of work in internal fluid mechanics, high-temperature materials, structural analysis, instrumentation and controls.

  2. First Annual High-Speed Research Workshop, part 4

    NASA Technical Reports Server (NTRS)

    Whitehead, Allen H., Jr. (Compiler)

    1992-01-01

    Papers presented at the First Annual High Speed Research Workshop held in Williamsburg, Viginia, on May 14-16, 1991 are presented. This NASA-sponsored workshop provided a national forum for presenting and discussing important technology issues related to the definition of an economically viable and environmentally compatible High Speed Civil Transport. The sessions are developed around the technical components of NASA's Phase 1 High Speed Research Program which addresses the environmental issues of atmospheric emissions, community noise, and sonic boom. In particular, this part of the publication, Part 4, addresses high lift research and supersonic laminar flow control.

  3. Experimental ball bearing dynamics study. [by high speed photography

    NASA Technical Reports Server (NTRS)

    Signer, H. R.

    1973-01-01

    A photographic method was employed to record the kinematic performance of rolling elements in turbo machinery ball bearings. The 110 mm split inner ring test bearings had nominal contact angles of 26 deg and 34 deg. High speed films were taken at inner ring speeds of 4,000, 8,000 and 12,000 rpm and at thrust loads of 4,448 N and 22,240 N (1,000 and 5,000 lbs). The films were measured and this data reduced to obtain separator speed, ball speed and ball spin axis orientation.

  4. Review of High-Speed Fiber Optic Grating Sensors Systems

    SciTech Connect

    Udd, E; Benterou, J; May, C; Mihailov, S J; Lu, P

    2010-03-24

    Fiber grating sensors can be used to support a wide variety of high speed measurement applications. This includes measurements of vibrations on bridges, traffic monitoring on freeways, ultrasonic detection to support non-destructive tests on metal plates and providing details of detonation events. This paper provides a brief overview of some of the techniques that have been used to support high speed measurements using fiber grating sensors over frequency ranges from 10s of kHz, to MHZ and finally toward frequencies approaching the GHz regime. Very early in the development of fiber grating sensor systems it was realized that a high speed fiber grating sensor system could be realized by placing an optical filter that might be a fiber grating in front of a detector so that spectral changes in the reflection from a fiber grating were amplitude modulated. In principal the only limitation on this type of system involved the speed of the output detector which with the development of high speed communication links moved from the regime of 10s of MHz toward 10s of GHz. The earliest deployed systems involved civil structures including measurements of the strain fields on composite utility poles and missile bodies during break tests, bridges and freeways. This was followed by a series of developments that included high speed fiber grating sensors to support nondestructive testing via ultrasonic wave detection, high speed machining and monitoring ship hulls. Each of these applications involved monitoring mechanical motion of structures and thus interest was in speeds up to a few 10s of MHz. Most recently there has been interest in using fiber grating to monitor the very high speed events such as detonations and this has led to utilization of fiber gratings that are consumed during an event that may require detection speeds of hundreds of MHz and in the future multiple GHz.

  5. High-speed LWR transients simulation for optimizing emergency response

    SciTech Connect

    Wulff, W.; Cheng, H.S.; Lekach, S.V.; Mallen, A.N.; Stritar, A.

    1984-11-19

    The purpose of computer-assisted emergency response in nuclear power plants, and the requirements for achieving such a response, are presented. An important requirement is the attainment of realistic high-speed plant simulations at the reactor site. Currently pursued development programs for plant simulations are reviewed. Five modeling principles are established and a criterion is presented for selecting numerical procedures and efficient computer hardware to achieve high-speed simulations. A newly developed technology for high-speed power plant simulation is described and results are presented. It is shown that simulation speeds ten times greater than real-time process-speeds are possible, and that plant instrumentation can be made part of the computational loop in a small, on-site minicomputer. Additional technical issues are presented which must still be resolved before the newly developed technology can be implemented in a nuclear power plant.

  6. The Lag Model Applied to High Speed Flows

    NASA Technical Reports Server (NTRS)

    Olsen, Michael E.; Coakley, Thomas J.; Lillard, Randolph P.

    2005-01-01

    The Lag model has shown great promise in prediction of low speed and transonic separations. The predictions of the model, along with other models (Spalart-Allmaras and Menter SST) are assessed for various high speed flowfields. In addition to skin friction and separation predictions, the prediction of heat transfer are compared among these models, and some fundamental building block flowfields, are investigated.

  7. Incorporating YBCO Coated Conductors in High-speed Superconducting Generators

    DTIC Science & Technology

    2008-07-01

    4.0 kW/lb (8.82 kW/kg). The machine configuration chosen by GE for design was a homopolar inductor alternator (HIA) which locates the...extremely severe ac loss environment. Even if this is ultimately impossible for high speed generators, it may not preclude lower speed motors and

  8. Application Of High Speed Photography In Science And Technology

    NASA Astrophysics Data System (ADS)

    Wu Ji-Zong, Wu; Yu-Ju, Lin

    1983-03-01

    The service works in high-speed photography carried out by the Department of Precision Instruments, Tianjin University are described in this paper. A compensation type high-speed camera was used in these works. The photographic methods adopted and better results achieved in the studies of several technical fields, such as velocity field of flow of overflow surface of high dam, combustion process of internal combustion engine, metal cutting, electrical are welding, experiment of piling of steel tube piles for supporting the marine platforms and characteristics of motion of wrist watch escape mechanism and so on are illustrated in more detail. As the extension of human visual organs and for increasing the abi-lities of observing and studying the high-speed processes, high-speed photography plays a very important role. In order to promote the application and development on high-speed photography, we have carried out the consultative and service works inside and outside Tianjin Uni-versity. The Pentazet 35 compensation type high-speed camera, made in East Germany, was used to record the high-speed events in various kinds of technical investigations and necessary results have been ob-tained. 1. Measurement of flow velocity on the overflow surface of high dam. In the design of a key water control project with high head, it is extremely necessary to determinate various characteristics of flow velocity field on the overflow surface of high dam. Since the water flow on the surface of high overflow dam possesses the features of large flow velocity and shallow water depth, therefore it is difficult to use the conventional current meters such as pilot tube, miniature cur-rent meter or electrical measuring methods of non-electrical quantities for studying this problem. Adopting the high-speed photographic method to study analogously the characteristics of flow velocity field on the overflow surface of high dam is a kind of new measuring method. People

  9. Design of high speed LVDS transceiver ICs

    NASA Astrophysics Data System (ADS)

    Jian, Xu; Zhigong, Wang; Xiaokang, Niu

    2010-07-01

    The design of low-power LVDS (low voltage differential signaling) transceiver ICs is presented. The LVDS transmitter integrates a common-mode feedback control on chip, while a specially designed pre-charge circuit is proposed to improve the speed of the circuit, making the highest data rate up to 622 Mb/s. For the LVDS receiver design, the performance degradation issues are solved when handling the large input common mode voltages of the conventional LVDS receivers. In addition, the LVDS receiver also supports the failsafe function. The transceiver chips were verified with the CSMC 0.5-μm CMOS process. The measured results showed that, for the LVDS transmitter with the pre-charge technique proposed, the maximum data rate is higher than 622 Mb/s. The power consumption is 6 mA with a 5-V power supply. The LVDS receiver can work properly with a larger input common mode voltage (0.1-2.4 V) but a differential input voltage as low as 100 mV. The power consumption is only 1.2 mA with a 5-V supply at the highest data rate of 400 Mb/s. The chip set meets the TIA/EIA-644-A standards and shows its potential prospects in LVDS transmission systems.

  10. High Speed Measurements using Fiber-optic Bragg Grating Sensors

    SciTech Connect

    Benterou, J J; May, C A; Udd, E; Mihailov, S J; Lu, P

    2011-03-26

    Fiber grating sensors may be used to monitor high-speed events that include catastrophic failure of structures, ultrasonic testing and detonations. This paper provides insights into the utility of fiber grating sensors to measure structural changes under extreme conditions. An emphasis is placed on situations where there is a structural discontinuity. Embedded chirped fiber Bragg grating (CFBG) sensors can track the very high-speed progress of detonation waves (6-9 km/sec) inside energetic materials. This paper discusses diagnostic instrumentation and analysis techniques used to measure these high-speed events.

  11. Trend on High-speed Power Line Communication Technology

    NASA Astrophysics Data System (ADS)

    Ogawa, Osamu

    High-speed power line communication (PLC) is useful technology to easily build the communication networks, because construction of new infrastructure is not necessary. In Europe and America, PLC has been used for broadband networks since the beginning of 21th century. In Japan, high-speed PLC was deregulated only indoor usage in 2006. Afterward it has been widely used for home area network, LAN in hotels and school buildings and so on. And recently, PLC is greatly concerned as communication technology for smart grid network. In this paper, the author surveys the high-speed PLC technology and its current status.

  12. High-speed AFM of human chromosomes in liquid

    NASA Astrophysics Data System (ADS)

    Picco, L. M.; Dunton, P. G.; Ulcinas, A.; Engledew, D. J.; Hoshi, O.; Ushiki, T.; Miles, M. J.

    2008-09-01

    Further developments of the previously reported high-speed contact-mode AFM are described. The technique is applied to the imaging of human chromosomes at video rate both in air and in water. These are the largest structures to have been imaged with high-speed AFM and the first imaging in liquid to be reported. A possible mechanism that allows such high-speed contact-mode imaging without significant damage to the sample is discussed in the context of the velocity dependence of the measured lateral force on the AFM tip.

  13. High speed measurements using fiber-optic Bragg gratings

    NASA Astrophysics Data System (ADS)

    Benterou, Jerry; May, Chadd; Udd, Eric; Mihailov, Stephen J.; Lu, Ping

    2011-06-01

    Fiber grating sensors may be used to monitor high-speed events that include catastrophic failure of structures, ultrasonic testing and detonations. This paper provides insights into the utility of fiber grating sensors to measure structural changes under extreme conditions. An emphasis is placed on situations where there is a structural discontinuity. Embedded chirped fiber Bragg grating (CFBG) sensors can track the very high-speed progress of detonation waves (6-9 km/sec) inside energetic materials. This paper discusses diagnostic instrumentation and analysis techniques used to measure these high-speed events.

  14. First Annual High-Speed Research Workshop, part 3

    NASA Technical Reports Server (NTRS)

    Whitehead, Allen H., Jr. (Compiler)

    1992-01-01

    The First High-Speed Research (HSR) Workshop was hosted by NASA LaRC and was held 14-16 May 1991, in Williamsburg, Virginia. The purpose of the workshop was to provide a national forum for the government, industry, and university participants to present and discuss important technology issues related to the development of a commercially viable, environmentally compatible, U.S. High-Speed Civil Transport. The workshop sessions are organized around the major task elements in NASA's Phase 1 High-Speed Research Program which basically addresses the environmental issues of atmospheric emissions, community noise, and sonic boom.

  15. High-speed digital project, HSD test capability

    NASA Astrophysics Data System (ADS)

    Markley, R. E.; Elarton, J. L.; Allen, C. T.

    1994-04-01

    Establishing a high-speed digital (HSD) test capability for the Digital Waveform Synthesizer (DWS) multichip module (MCM) has required the development of several areas: a detailed test plan for the MCM; design, fabrication and proving of the high-speed test console; and the specification, design, and development of the high-speed test and environmental conditioning interface to the DWS. These development activities have been successfully completed at the Allied Signal Inc., Kansas City Division (KCD), and the test capability described herein is currently supporting DWS MCM testing and can be adapted to similar HSD module testing.

  16. Rat muscle blood flows during high-speed locomotion

    SciTech Connect

    Armstrong, R.B.; Laughlin, M.H.

    1985-10-01

    We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance.

  17. High speed high dynamic range high accuracy measurement system

    SciTech Connect

    Deibele, Craig E.; Curry, Douglas E.; Dickson, Richard W.; Xie, Zaipeng

    2016-11-29

    A measuring system includes an input that emulates a bandpass filter with no signal reflections. A directional coupler connected to the input passes the filtered input to electrically isolated measuring circuits. Each of the measuring circuits includes an amplifier that amplifies the signal through logarithmic functions. The output of the measuring system is an accurate high dynamic range measurement.

  18. MEMS-based high speed scanning probe microscopy.

    PubMed

    Disseldorp, E C M; Tabak, F C; Katan, A J; Hesselberth, M B S; Oosterkamp, T H; Frenken, J W M; van Spengen, W M

    2010-04-01

    The high speed performance of a scanning probe microscope (SPM) is improved if a microelectromechanical systems (MEMS) device is employed for the out-of-plane scanning motion. We have carried out experiments with MEMS high-speed z-scanners (189 kHz fundamental resonance frequency) in both atomic force microscope and scanning tunneling microscope modes. The experiments show that with the current MEMS z-scanner, lateral tip speeds of 5 mm/s can be achieved with full feedback on surfaces with significant roughness. The improvement in scan speed, obtained with MEMS scanners, increases the possibilities for SPM observations of dynamic processes. Even higher speed MEMS scanners with fundamental resonance frequencies in excess of a megahertz are currently under development.

  19. Highly Reliable, High-Speed, Unidirectional Serial Data Links

    NASA Technical Reports Server (NTRS)

    Cole, Robert M.; Bishop, Jamie

    2005-01-01

    Highly reliable, high-speed, unidirectional serial data-communication subsystems have been proposed to be installed in an upgrade of the computing systems aboard the space shuttles. The basic design concept of these serial data links is also adaptable to terrestrial use in applications in which there are requirements for highly reliable serial data communications. The hardware and software aspects of the architecture of the data links are dictated largely by a requirement, in the original space-shuttle application, for one computer to monitor the memory transactions and memory contents of other computers in real time with high reliability and without reliance on requests for retransmission. To minimize weight while affording a capability to transfer data at a required rate of 2.56 x 10(exp 8) bits per second, it was decided that the links would be serial ones of the fiber-channel type. [Fiber channel denotes a type of serial computer bus that is used to connect a computer (usually a supercomputer) with a high-speed data storage device. Depending on the specific application, the physical connection between the transmitter and receiver could be made via an optical fiber or a twisted pair of wires.] Heretofore, fiber-channel links have ordinarily been bidirectional and have operated under protocols that provide for receiving stations to detect errors and request retransmission when necessary. In the present case, the time taken by processing to request retransmission would conflict with the requirement for real-time transfer of data. To ensure reliability without retransmission, a link according to the proposal would utilize a modified version of the normal fiberchannel character set in conjunction with forward error correction by means of a Reed-Solomon code (see figure). The Reed-Solomon encoding and decoding and the translations between the normal and modified character sets would be effected by logic circuitry external to the fiber-channel transmitter and receiver

  20. Low- and high-frequency nonlinear acoustic phenomena in a magnesite.

    PubMed

    Nazarov, V E; Kolpakov, A B

    2014-02-01

    The results of experimental and theoretical studies of nonlinear acoustic phenomena (amplitude-dependent losses, resonant frequency shifts, damping of weak ultrasonic pulses and their carrier frequency phase delay under action of a powerful low-frequency pumping wave as well as amplitude-phase self-action of the finite-amplitude ultrasonic pulses) in a magnesite rod are presented. Analytical description of the observed phenomena was carried out within the frameworks of the phenomenological state equations that contain low-frequency hysteretic nonlinearity and both high-frequency dissipative and elastic nonlinearity. From comparison of experimental and analytical amplitude-frequency dependences of nonlinear phenomena, the values of magnesite acoustic nonlinearity parameters were determined. The frequency dependences have been discovered for hysteretic (in a range 3.6-17.2 kHz) as well as dissipative and elastic nonlinearity (in a range 50-370 kHz).

  1. Distance phenomena in high-dimensional chemical descriptor spaces: consequences for similarity-based approaches.

    PubMed

    Rupp, Matthias; Schneider, Petra; Schneider, Gisbert

    2009-11-15

    Measuring the (dis)similarity of molecules is important for many cheminformatics applications like compound ranking, clustering, and property prediction. In this work, we focus on real-valued vector representations of molecules (as opposed to the binary spaces of fingerprints). We demonstrate the influence which the choice of (dis)similarity measure can have on results, and provide recommendations for such choices. We review the mathematical concepts used to measure (dis)similarity in vector spaces, namely norms, metrics, inner products, and, similarity coefficients, as well as the relationships between them, employing (dis)similarity measures commonly used in cheminformatics as examples. We present several phenomena (empty space phenomenon, sphere volume related phenomena, distance concentration) in high-dimensional descriptor spaces which are not encountered in two and three dimensions. These phenomena are theoretically characterized and illustrated on both artificial and real (bioactivity) data.

  2. FPGA Flash Memory High Speed Data Acquisition

    NASA Technical Reports Server (NTRS)

    Gonzalez, April

    2013-01-01

    The purpose of this research is to design and implement a VHDL ONFI Controller module for a Modular Instrumentation System. The goal of the Modular Instrumentation System will be to have a low power device that will store data and send the data at a low speed to a processor. The benefit of such a system will give an advantage over other purchased binary IP due to the capability of allowing NASA to re-use and modify the memory controller module. To accomplish the performance criteria of a low power system, an in house auxiliary board (Flash/ADC board), FPGA development kit, debug board, and modular instrumentation board will be jointly used for the data acquisition. The Flash/ADC board contains four, 1 MSPS, input channel signals and an Open NAND Flash memory module with an analog to digital converter. The ADC, data bits, and control line signals from the board are sent to an Microsemi/Actel FPGA development kit for VHDL programming of the flash memory WRITE, READ, READ STATUS, ERASE, and RESET operation waveforms using Libero software. The debug board will be used for verification of the analog input signal and be able to communicate via serial interface with the module instrumentation. The scope of the new controller module was to find and develop an ONFI controller with the debug board layout designed and completed for manufacture. Successful flash memory operation waveform test routines were completed, simulated, and tested to work on the FPGA board. Through connection of the Flash/ADC board with the FPGA, it was found that the device specifications were not being meet with Vdd reaching half of its voltage. Further testing showed that it was the manufactured Flash/ADC board that contained a misalignment with the ONFI memory module traces. The errors proved to be too great to fix in the time limit set for the project.

  3. High-speed digital signal normalization for feature identification

    NASA Technical Reports Server (NTRS)

    Ortiz, J. A.; Meredith, B. D.

    1983-01-01

    A design approach for high speed normalization of digital signals was developed. A reciprocal look up table technique is employed, where a digital value is mapped to its reciprocal via a high speed memory. This reciprocal is then multiplied with an input signal to obtain the normalized result. Normalization improves considerably the accuracy of certain feature identification algorithms. By using the concept of pipelining the multispectral sensor data processing rate is limited only by the speed of the multiplier. The breadboard system was found to operate at an execution rate of five million normalizations per second. This design features high precision, a reduced hardware complexity, high flexibility, and expandability which are very important considerations for spaceborne applications. It also accomplishes a high speed normalization rate essential for real time data processing.

  4. How do Turkish High School Graduates Use the Wave Theory of Light to Explain Optics Phenomena?

    ERIC Educational Resources Information Center

    Sengoren, S. K.

    2010-01-01

    This research was intended to investigate whether Turkish students who had graduated from high school used the wave theory of light properly in explaining optical phenomena. The survey method was used in this research. The data, which were collected from 175 first year university students in Turkey, were analysed quantitatively and qualitatively.…

  5. How do Turkish High School Graduates Use the Wave Theory of Light to Explain Optics Phenomena?

    ERIC Educational Resources Information Center

    Sengoren, S. K.

    2010-01-01

    This research was intended to investigate whether Turkish students who had graduated from high school used the wave theory of light properly in explaining optical phenomena. The survey method was used in this research. The data, which were collected from 175 first year university students in Turkey, were analysed quantitatively and qualitatively.…

  6. Plasma measurement by optical visualization and triple probe method under high-speed impact

    NASA Astrophysics Data System (ADS)

    Sakai, T.; Umeda, K.; Kinoshita, S.; Watanabe, K.

    2017-02-01

    High-speed impact on spacecraft by space debris poses a threat. When a high-speed projectile collides with target, it is conceivable that the heat created by impact causes severe damage at impact point. Investigation of the temperature is necessary for elucidation of high-speed impact phenomena. However, it is very difficult to measure the temperature with standard methods for two main reasons. One reason is that a thermometer placed on the target is instantaneously destroyed upon impact. The other reason is that there is not enough time resolution to measure the transient temperature changes. In this study, the measurement of plasma induced by high-speed impact was investigated to estimate temperature changes near the impact point. High-speed impact experiments were performed with a vertical gas gun. The projectile speed was approximately 700 m/s, and the target material was A5052. The experimental data to calculate the plasma parameters of electron temperature and electron density were measured by triple probe method. In addition, the diffusion behavior of plasma was observed by optical visualization technique using high-speed camera. The frame rate and the exposure time were 260 kfps and 1.0 μs, respectively. These images are considered to be one proof to show the validity of plasma measurement. The experimental results showed that plasma signals were detected for around 70 μs, and the rising phase of the wave form was in good agreement with timing of optical visualization image when the plasma arrived at the tip of triple probe.

  7. High-speed event detector for embedded nanopore bio-systems.

    PubMed

    Huang, Yiyun; Magierowski, Sebastian; Ghafar-Zadeh, Ebrahim; Wang, Chengjie

    2015-08-01

    Biological measurements of microscopic phenomena often deal with discrete-event signals. The ability to automatically carry out such measurements at high-speed in a miniature embedded system is desirable but compromised by high-frequency noise along with practical constraints on filter quality and sampler resolution. This paper presents a real-time event-detection method in the context of nanopore sensing that helps to mitigate these drawbacks and allows accurate signal processing in an embedded system. Simulations show at least a 10× improvement over existing on-line detection methods.

  8. Effects of high-speed power training on muscle performance and braking speed in older adults.

    PubMed

    Sayers, Stephen P; Gibson, Kyle

    2012-01-01

    We examined whether high-speed power training (HSPT) improved muscle performance and braking speed using a driving simulator. 72 older adults (22 m, 50 f; age = 70.6 ± 7.3 yrs) were randomized to HSPT at 40% one-repetition maximum (1RM) (HSPT: n = 25; 3 sets of 12-14 repetitions), slow-speed strength training at 80%1RM (SSST: n = 25; 3 sets of 8-10 repetitions), or control (CON: n = 22; stretching) 3 times/week for 12 weeks. Leg press and knee extension peak power, peak power velocity, peak power force/torque, and braking speed were obtained at baseline and 12 weeks. HSPT increased peak power and peak power velocity across a range of external resistances (40-90% 1RM; P < 0.05) and improved braking speed (P < 0.05). Work was similar between groups, but perceived exertion was lower in HSPT (P < 0.05). Thus, the less strenuous HSPT exerted a broader training effect and improved braking speed compared to SSST.

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

    NASA Astrophysics Data System (ADS)

    Gallier, Kirk

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

  10. Driver assist behaviors for high-speed small UGVs

    NASA Astrophysics Data System (ADS)

    Yamauchi, Brian

    2011-05-01

    Currently deployed small UGVs operate at speeds up to around 6 mph and have proven their usefulness in explosives ordnance disposal (EOD) missions. As part of the TARDEC-funded Stingray Project, iRobot is investigating techniques to increase the speed of small UGVs so they can be useful in a wider range of missions, such as high-speed reconnaissance and infantry assault missions. We have developed a prototype Stingray PackBot, using wheels rather than tracks, that is capable of traveling at speeds up to 18 mph. A key issue when traveling at such speeds is how to maintain stability during sharp turns and over rough terrain. We are developing driver assist behaviors that will provide dynamic stability control for high-speed small UGVs using techniques such as dynamic weight shifting to limit oversteer and understeer. These driver assist behaviors will enable operators to use future high-speed small UGVs in high optempo infantry missions and keep warfighters out of harm's way.

  11. High-speed seal and bearing test facility

    NASA Technical Reports Server (NTRS)

    Panos, Jean B.

    1994-01-01

    The following topics are discussed in this viewgraph presentation: high speed seal/bearing rig background, project status, facility features, test rig capabilities, EMD testing advantages, and future opportunities.

  12. Design of high speed camera based on CMOS technology

    NASA Astrophysics Data System (ADS)

    Park, Sei-Hun; An, Jun-Sick; Oh, Tae-Seok; Kim, Il-Hwan

    2007-12-01

    The capacity of a high speed camera in taking high speed images has been evaluated using CMOS image sensors. There are 2 types of image sensors, namely, CCD and CMOS sensors. CMOS sensor consumes less power than CCD sensor and can take images more rapidly. High speed camera with built-in CMOS sensor is widely used in vehicle crash tests and airbag controls, golf training aids, and in bullet direction measurement in the military. The High Speed Camera System made in this study has the following components: CMOS image sensor that can take about 500 frames per second at a resolution of 1280*1024; FPGA and DDR2 memory that control the image sensor and save images; Camera Link Module that transmits saved data to PC; and RS-422 communication function that enables control of the camera from a PC.

  13. High speed testing of the hollow roller bearing

    NASA Astrophysics Data System (ADS)

    Bowen, W. L.; Murphy, T. W., Jr.

    1980-08-01

    This bearing with its preloaded, hollow rollers has the qualities required for high speed operation. Roller hollowness improves cooling ability and its lighter weight reduces the centrifugal force against the raceway. Preloading between inner and outer races for 360 deg insures good roller guidance and minimizes roller skidding. However, the problems of operating a full complement of rollers at very high speeds were unknown. Also, limitations caused by roller bending fatigue needed investigation. To answer these questions, a high speed test machine was constructed and a hollow roller test bearing was designed for operation at 3 million DN. This paper describes the construction of a high speed test cell and subsequent testing of a full complement, preloaded, 115 mm hollow roller bearing. Testing culminated in a successful endurance test of 1000 hours at 26,100 RPM (3 million DN). The results verified several advantages regarding roller stability and antiskidding qualities as well as demonstrating a unique fail-safe condition.

  14. Discharge characteristics of a high speed fuel injection system

    NASA Technical Reports Server (NTRS)

    Matthews, Robertson

    1925-01-01

    Discussed here are some discharge characteristics of a fuel injection system intended primarily for high speed service. The system consisted of a cam actuated fuel pump, a spring loaded automatic injection valve, and a connecting tube.

  15. The High Speed Photometer for the Space Telescope

    NASA Technical Reports Server (NTRS)

    Bless, R. C.

    1982-01-01

    An overview of the high speed photometer (HSP), its optics and detectors, its electronics, its mechanical structure, and some observational considerations are presented. The capabilities and limitations of the HSP are outlined.

  16. The flight of an autogiro at high speed

    NASA Technical Reports Server (NTRS)

    Bennett, J A J

    1933-01-01

    This report presents a method for computing the flight performance of an autogiro at high speed, the velocity component along the blades being accounted for by calculation of the profile drag and the equation for zero torque.

  17. High-speed vertical cavity surface emitting lasers

    SciTech Connect

    Lear, K.L.; Ochiai, M.; Hietala, V.M.

    1997-03-01

    High speed modulation and pulsing are reported for oxide-confined vertical cavity surface emitting laser diodes (VCSELs) with inverted doping and proton implantation to reduce the extrinsic limitations.

  18. High Speed Multiplex Bus Protocol Study.

    DTIC Science & Technology

    1980-06-15

    Transaction 42-45 3.3.4.1-1 High Level Bus State Transition Diagram; BC-RT 48 Poll or Transaction Request 3.3.4.1-2 Response Time Out Interval Measurement 49...61 3.4-2 General Message Types 62 3.4.3-1 High Level BC State Transition Diagram - BC-RT 64 Transaction Request 3.4.3-2 High Level RT State Transition...the data base for each bus unit contains the current state of that bus unit with respect to ongoing bus communications. The bus control data base

  19. Explosive-driven, high speed, arcless switch

    DOEpatents

    Skogmo, P.J.; Tucker, T.J.

    1987-07-14

    An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed. 7 figs.

  20. Explosive-driven, high speed, arcless switch

    DOEpatents

    Skogmo, P.J.; Tucker, T.J.

    1986-05-02

    An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

  1. Explosive-driven, high speed, arcless switch

    DOEpatents

    Skogmo, Phillip J.; Tucker, Tillman J.

    1987-01-01

    An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

  2. Technology needs for high-speed rotorcraft, volume 1

    NASA Technical Reports Server (NTRS)

    Wilkerson, J. B.; Schneider, J. J.; Bartie, K. M.

    1991-01-01

    High-speed rotorcraft concepts and the technology needed to extend rotorcraft cruise speeds up to 450 knots (while retaining the helicopter attributes of low downwash velocities) were identified. Task I identified 20 concepts with high-speed potential. These concepts were qualitatively evaluated to determine the five most promising ones. These five concepts were designed with optimum wing loading and disk loading to a common NASA-defined military transport mission. The optimum designs were quantitatively compared against 11 key criteria and ranked accordingly. The two highest ranking concepts were selected for the further study.

  3. Reduced Order Modeling For High Speed Flows with Moving Shocks

    DTIC Science & Technology

    2001-12-03

    use of Proper Orthogonal Decomposition ( POD ) for reduced order modeling (ROM)of fluid problems is extended to high-speed compressible fluid flows. The...challenge in using POD for high-speed flows is presented by the presence of moving discontinuities in the flow field. To ovecome these difficulties...difficulty. The accuracy and order reduction of the domain decomposition POD /ROM approach is quantified for each application. ROMs with as large as three

  4. High speed data transmission at the Superconducting Super Collider

    SciTech Connect

    Leskovar, B. )

    1991-04-01

    In this paper high speed data transmission using fiber optics in the data acquisition system of the Superconducting Super Collider has been investigated. Emphasis is placed on the high speed data transmission system overview, the local data network and on subassemblies, such as optical transmitters and receivers. Also, the performance of candidate subassemblies having a low power dissipation for the data acquisition system is discussed.

  5. High Speed Computing, LANs, and WAMs

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.; Monacos, Steve

    1994-01-01

    Optical fiber networks may one day offer potential capacities exceeding 10 terabits/sec. This paper describes present gigabit network techniques for distributed computing as illustrated by the CASA gigabit testbed, and then explores future all-optic network architectures that offer increased capacity, more optimized level of service for a given application, high fault tolerance, and dynamic reconfigurability.

  6. High Speed Computing, LANs, and WAMs

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.; Monacos, Steve

    1994-01-01

    Optical fiber networks may one day offer potential capacities exceeding 10 terabits/sec. This paper describes present gigabit network techniques for distributed computing as illustrated by the CASA gigabit testbed, and then explores future all-optic network architectures that offer increased capacity, more optimized level of service for a given application, high fault tolerance, and dynamic reconfigurability.

  7. High-speed photography of high-resolution moire patterns

    NASA Astrophysics Data System (ADS)

    Whitworth, Martin B.; Huntley, Jonathan M.; Field, John E.

    1991-04-01

    The techniques of high resolution moire photography and high speed photography have been combined to allow measurement of the in-plane components of a transient displacement field with microsecond time resolution. Specimen gratings are prepared as casts in a thin layer of epoxy resin on the surface of a specimen. These are illuminated with a flash tube and imaged onto a reference grating with a specially modified camera lens, which incorporates a slotted mask in the aperture plane. For specimen gratings of 75 lines mm1, this selects the +1 and -1 order diffracted beams, thus doubling the effective grating frequency to 150 lines mm1. The resulting real-time moire fringes are recorded with a Hadland 792 image converter camera (Imacon) at an inter-frame time of 2-5ts. The images are digitised and an automatic fringe analysis technique based on the 2-D Fourier transform method is used to extract the displacement information. The technique is illustrated by the results of an investigation into the transient deformation of composite disc specimens, impacted with rectangular metal sliders fired from a gas gun.

  8. The Use Of High Speed Photography In Reactor Safety Studies At The Atomic Energy Establishment, Winfrith

    NASA Astrophysics Data System (ADS)

    Maddison, R. J.

    1985-02-01

    The investigation of certain areas of nuclear reactor safety involves the study of high speed phenomena with timescales ranging from microseconds to a few hundreds of milliseconds. Examples which have been extensively studied at Winfrith are firstly, the thermal interaction of molten fuel and reactor coolant which can generate high pressures on the 100 msec timescale, and which involves phenomena such as vapour film collapse which takes place on the microsecond timescale. Secondly, there is the response of reactor structures to such pressures, and finally there is the response of structural materials such as metals and concrete to the impulsive loading arising from the impact of heavy, high velocity missiles. A wide range of experimental techniques is used in these studies, many of which have been developed specially for this type of work which ranges from small laboratory scale to large field scale experiments. There are two important features which characterise many of these experiments:- i) a long period of meticulous preparation of very heavily instrumented, short duration experiments and; ii) the destructive nature of the experiments. Various forms of High Speed photography are included in the inventory of experimental techniques. These include the use of single and double exposure, short duration, spark photography; the use of an Image Convertor Camera (IMACON 790); and a number of rotating prism cine cameras. High Speed Photography is used both in a primary experimental role in the studies, and in a supportive role for other instrumentation. Because of the sometimes violent nature of these experiments, cameras are often heavily protected and operated remotely; lighting systems are sometimes destroyed. This has led to the development of unconventional techniques for camera operation and subject lighting. This paper will describe some of the experiments and the way in which High Speed Photography has been applied as an essential experimental tool. It will be

  9. A new design for a high speed spindle

    SciTech Connect

    Weck, M.; Fischer, S.; Holster, P.; Carlisle, K.; Chen, Y.

    1996-12-31

    Precision grinding and micromachining both impose high demands on the machine behavior, since the achievable workpiece accuracy is determined not only by the technological parameters but also by the characteristics of the applicated machine components. Ultraprecision surface quality and the mechanical fabrication of structures in the micron range can only be achieved by using machine tools which have appropriate spindles. Structures cannot be manufactured using spindle types of which the radial error motion is greater than the level of contour accuracy or surface roughness required. In addition, the spindle speed is an important value. Not only a certain cutting speed is needed from the technological point of view, but also the machining time required for microstructuring surfaces is reduced by deploying a high frequency spindle, thereby increasing the economic efficiency of the technique. Hence, the main purpose of the project was to develop a high speed spindle with properties concerning accuracy, speed and stiffness beyond commercially available ones.

  10. High speed cineradiography using electronic imaging

    NASA Astrophysics Data System (ADS)

    Lucero, J. P.; Fry, D. A.; Gaskill, W. E.; Henderson, R. L.; Crawford, T. R.; Carey, N. E.

    1992-12-01

    The Los Alamos National Laboratory has constructed and is now operating a cineradiography system for imaging and evaluation of ballistic interaction events at the 1200 meter range of the Terminal Effects Research and Analysis (TERA) Group at the New Mexico Institute of Mining and Technology. Cineradiography is part of a complete firing, tracking, and analysis system at the range. The cine system consists of flash x-ray sources illuminating a one-half meter by two meter fast phosphor screen which is viewed by gated-intensified high resolution still video cameras via turning mirrors. The entire system is armored to protect against events containing up to 13.5 kg of high explosive. Digital images are available for immediate display and processing. The system is capable of frame rates up to 10(exp 5)/sec for up to five total images.

  11. High-speed cineradiography using electronic imaging

    NASA Astrophysics Data System (ADS)

    Lucero, Jacob P.; Fry, David A.; Gaskill, William E.; Henderson, R. L.; Crawford, Ted R.; Carey, N. E.

    1993-01-01

    The Los Alamos National Laboratory has constructed and is now operating a cineradiography system for imaging and evaluation of ballistic interaction events at the 1200 meter range of the Terminal Effects Research and Analysis (TERA) Group at the New Mexico Institute of Mining and Technology. Cineradiography is part of a complete firing, tracking, and analysis system at the range. The cine system consists of flash x-ray sources illuminating a one-half meter by two meter fast phosphor screen which is viewed by gated-intensified high resolution still video cameras via turning mirrors. The entire system is armored to protect against events containing up to 13.5 kg of high explosive. Digital images are available for immediate display and processing. The system is capable of frame rates up to 105/sec for up to five total images.

  12. High-speed quantum networking by ship

    PubMed Central

    Devitt, Simon J.; Greentree, Andrew D.; Stephens, Ashley M.; Van Meter, Rodney

    2016-01-01

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet. PMID:27805001

  13. High-speed quantum networking by ship.

    PubMed

    Devitt, Simon J; Greentree, Andrew D; Stephens, Ashley M; Van Meter, Rodney

    2016-11-02

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet.

  14. High-speed quantum networking by ship

    NASA Astrophysics Data System (ADS)

    Devitt, Simon J.; Greentree, Andrew D.; Stephens, Ashley M.; van Meter, Rodney

    2016-11-01

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet.

  15. Influence of ordering phenomena on the magnetostriction of high Si alloys for electrical applications

    SciTech Connect

    Ros-Yanez, Tanya; Ruiz, Daniel; Lopez, Diego; Hilgert, Tom; Dupre, Luc; Vandenberghe, Robert E.; Houbaert, Yvan

    2005-05-15

    The present work attempts to assess the influence of order phenomena on the magnetostriction of high Fe-Si alloys for electrical applications. The magnetostriction of high silicon electrical steels in the range of 4 to 6 wt. % Si was studied regarding the effect of processing and thermal treatment. In addition, power losses and saturation magnetization measurements were performed and {sup 57}Fe Moessbauer spectroscopy was used to evaluate and quantify the degree of order.

  16. High-speed integrated electroabsorption modulators

    NASA Astrophysics Data System (ADS)

    Johnson, John E.; Morton, Paul A.; Park, Yong-Kwan; Ketelsen, Leonard J. P.; Grenko, J. A.; Miller, Thomas J.; Sputz, Sharon K.; Tanbun-Ek, Tawee; Vandenberg, J. M.; Yadvish, R. D.; Fullowan, Thomas R.; Sciortino, Paul F., Jr.; Sergent, A. M.; Tsang, Won-Tien

    1997-04-01

    The explosive growth in internet, multimedia and wireless traffic in recent years is rapidly exhausting capacity in public networks worldwide, forcing network service providers to aggressively install new lines and upgrade old ones. Fortunately, technological breakthroughs in the areas of erbium-doped fiber amplifiers (EDFA's), passive wavelength demultiplexers and low chirp sources have made all-optical dense wavelength-division multiplexed (WDM) systems a cost- effective way to utilize the vast bandwidth already available in the embedded fiber plant. WDM systems offer additional operational advantages, including high ultimate capacity, bit-rate transparency, flexible growth strategies, and the potential to use all-optical wavelength routing in future broadband network architectures. Commercial WDM systems operating at the OC-48 (2.5 Gbit/s) line rate are now available, and OC-192 (10 Gbit/s) terminal equipment which is under development will further enhance the capacity of these systems. One of the keys to viable WDM systems is the availability of inexpensive low-chirp optical transmitters. By taking advantage of photonic integrated circuit technology, it is possible to produce monolithically integrated DFB laser/EA modulators (EML's) with low chirp, low drive voltage and high extinction ratio, in a single compact package. In this talk we discuss the operating characteristics of these devices and their relationship to WDM system performance.

  17. Coal-fueled high-speed diesel engine development

    SciTech Connect

    Kakwani, R. M.; Winsor, R. E.; Ryan, III, T. W.; Schwalb, J. A.; Wahiduzzaman, S.; Wilson, Jr., R. P.

    1991-11-01

    The objectives of this program are to study combustion feasibility by running Series 149 engine tests at high speeds with a fuel injection and combustion system designed for coal-water-slurry (CWS). The following criteria will be used to judge feasibility: (1) engine operation for sustained periods over the load range at speeds from 600 to 1900 rpm. The 149 engine for mine-haul trucks has a rated speed of 1900 rpm; (2) reasonable fuel economy and coal burnout rate; (3) reasonable cost of the engine design concept and CWS fuel compared to future oil prices.

  18. Faster Fluorescence Microscopy: Advances in High Speed Biological Imaging

    PubMed Central

    Winter, Peter W.; Shroff, Hari

    2014-01-01

    The past decade has seen explosive growth in new high speed imaging methods. These can broadly be classified as either point-scanning (which offer better depth penetration) or parallelized systems (which offer higher speed). We discuss each class generally, and cover specific advances in diffraction-limited microscopes (laser-scanning confocal, spinning-disk, and light-sheet) and super-resolution microscopes (single-molecule imaging, stimulated emission-depletion, and structured illumination). A theme of our review is that there is no free lunch: each technique has strengths and weaknesses, and an advance in speed usually comes at the expense of either spatial resolution or depth penetration. PMID:24815857

  19. Faster fluorescence microscopy: advances in high speed biological imaging.

    PubMed

    Winter, Peter W; Shroff, Hari

    2014-06-01

    The past decade has seen explosive growth in new high speed imaging methods. These can broadly be classified as either point-scanning (which offer better depth penetration) or parallelized systems (which offer higher speed). We discuss each class generally, and cover specific advances in diffraction-limited microscopes (laser-scanning confocal, spinning-disk, and light-sheet) and superresolution microscopes (single-molecule imaging, stimulated emission-depletion, and structured illumination). A theme of our review is that there is no free lunch: each technique has strengths and weaknesses, and an advance in speed usually comes at the expense of either spatial resolution or depth penetration.

  20. Control structures for high speed processors

    NASA Technical Reports Server (NTRS)

    Maki, G. K.; Mankin, R.; Owsley, P. A.; Kim, G. M.

    1982-01-01

    A special processor was designed to function as a Reed Solomon decoder with throughput data rate in the Mhz range. This data rate is significantly greater than is possible with conventional digital architectures. To achieve this rate, the processor design includes sequential, pipelined, distributed, and parallel processing. The processor was designed using a high level language register transfer language. The RTL can be used to describe how the different processes are implemented by the hardware. One problem of special interest was the development of dependent processes which are analogous to software subroutines. For greater flexibility, the RTL control structure was implemented in ROM. The special purpose hardware required approximately 1000 SSI and MSI components. The data rate throughput is 2.5 megabits/second. This data rate is achieved through the use of pipelined and distributed processing. This data rate can be compared with 800 kilobits/second in a recently proposed very large scale integration design of a Reed Solomon encoder.

  1. Aeroacoustics of Turbulent High-Speed Jets

    NASA Technical Reports Server (NTRS)

    Rao, Ram Mohan; Lundgren, Thomas S.

    1996-01-01

    Aeroacoustic noise generation in a supersonic round jet is studied to understand in particular the effect of turbulence structure on the noise without numerically compromising the turbulence itself. This means that direct numerical simulations (DNS's) are needed. In order to use DNS at high enough Reynolds numbers to get sufficient turbulence structure we have decided to solve the temporal jet problem, using periodicity in the direction of the jet axis. Physically this means that turbulent structures in the jet are repeated in successive downstream cells instead of being gradually modified downstream into a jet plume. Therefore in order to answer some questions about the turbulence we will partially compromise the overall structure of the jet. The first section of chapter 1 describes some work on the linear stability of a supersonic round jet and the implications of this for the jet noise problem. In the second section we present preliminary work done using a TVD numerical scheme on a CM5. This work is only two-dimensional (plane) but shows very interesting results, including weak shock waves. However this is a nonviscous computation and the method resolves the shocks by adding extra numerical dissipation where the gradients are large. One wonders whether the extra dissipation would influence small turbulent structures like small intense vortices. The second chapter is an extensive discussion of preliminary numerical work using the spectral method to solve the compressible Navier-Stokes equations to study turbulent jet flows. The method uses Fourier expansions in the azimuthal and streamwise direction and a 1-D B-spline basis representation in the radial direction. The B-spline basis is locally supported and this ensures block diagonal matrix equations which are solved in O(N) steps. A very accurate highly resolved DNS of a turbulent jet flow is expected.

  2. Influence of sterilization on the corrosion resistance of high-speed dental handpieces.

    PubMed

    Angelini, E

    1992-03-01

    Ball bearings of high-speed dental handpieces were sterilized by various procedures and examined under scanning electron microscopy for evidence of corrosion. The metallic parts of ball bearings (rings and spheres), if not correctly lubricated, were dramatically corroded in chemical vapor and steam sterilizer. The nonmetallic parts (the retainers made of phenolic resins) appeared to be more sensitive to heat treatments, as revealed by the occurrence of darkening and embrittlement phenomena. In the absence of correct lubrication procedures, the performance of high-speed dental handpieces appears to be adversely influenced by sterilization, mostly in wet environments. On the other hand, daily maintenance that follows the manufacturer's instructions reduces and delays the damage to a great extent.

  3. High speed cine film studies of plasma behaviour and plasma surface interactions in tokamaks

    NASA Astrophysics Data System (ADS)

    Goodall, D. H. J.

    1982-12-01

    High speed cine photography is a useful diagnostic aid for studying plasma behaviour and plasma surface interactions. Several workers have filmed discharges in tokamaks including ASDEX, DITE, DIVA, ISX, JFT2, TFR and PLT. These films are discussed and examples given of the observed phenomena which include plasma limiter interactions, diverted discharges, disruptions, magnetic islands and moving glowing objects often known as 'UFOs'. Examples of plasma structures in ASDEX and DITE not previously published are also given. The paper also reports experiments in DITE to determine the origin of UFOs.

  4. Ultraviolet photometry of Nova Cygni 1992 obtained with the high speed photometer

    NASA Technical Reports Server (NTRS)

    Taylor, M.; Bless, R. C.; Oegelman, H.; Elliot, J. L.; Gallagher, J. S.; Nelson, M. J.; Percival, J. W.; Robinson, E. L.; Van Citters, G. W.

    1994-01-01

    In this Letter we present the first high-speed ultraviolet photometry of an active, classical nova, Nova Cygni 1992. The 45 minute observation shows significant evidence for power at frequencies that correspond to periods of about 565 and 900 s. Each of these periods has an amplitude of about 3 mmag. Since this data set is short, we cannot establish the nature of the detected variability and so, we discuss possible physical mechanisms ranging from short-lived phenomena to stable periodic modulations that could result in the observed variations.

  5. SPH simulations of high-speed collisions

    NASA Astrophysics Data System (ADS)

    Rozehnal, Jakub; Broz, Miroslav

    2016-10-01

    Our work is devoted to a comparison of: i) asteroid-asteroid collisions occurring at lower velocities (about 5 km/s in the Main Belt), and ii) mutual collisions of asteroids and cometary nuclei usually occurring at significantly higher relative velocities (> 10 km/s).We focus on differences in the propagation of the shock wave, ejection of the fragments and possible differences in the resultingsize-frequency distributions of synthetic asteroid families. We also discuss scaling with respect to the "nominal" target diameter D = 100 km, projectile velocity 3-7 km/s, for which a number of simulations were done so far (Durda et al. 2007, Benavidez et al. 2012).In the latter case of asteroid-comet collisions, we simulate the impacts of brittle or pre-damaged impactors onto solid monolithic targets at high velocities, ranging from 10 to 15 km/s. The purpose of this numerical experiment is to better understand impact processes shaping the early Solar System, namely the primordial asteroid belt during during the (late) heavy bombardment (as a continuation of Broz et al. 2013).For all hydrodynamical simulations we use a smoothed-particle hydrodynamics method (SPH), namely the lagrangian SPH3D code (Benz & Asphaug 1994, 1995). The gravitational interactions between fragments (re-accumulation) is simulated with the Pkdgrav tree-code (Richardson et al. 2000).

  6. High Speed Imaging of Diesel Fuel Sprays

    NASA Astrophysics Data System (ADS)

    Jackson, Ja'kira; Bittle, Joshua

    2016-11-01

    Fuel sprays primarily serve as methods for fuel distribution, fuel/air mixing, and atomization. In this research, a constant pressure flow rig vessel is being tested at various pressures and temperatures using n-heptane. The experiment requires two imaging techniques: color Schlieren and Mie-scatter. Schlieren captures density gradients in a spray which includes both liquid and vapor phases while Mie-scatter is only sensitive to the liquid phase of the fuel spray. Essentially, studies are mainly focused on extracting the liquid boundary from the Schlieren to possibly eliminate the need for acquiring the Mie-Scatter technique. Four test conditions (combination of low and high pressure and temperatures) are used in the application to attempt to find the liquid boundary independent of the Mie-scatter technique. In this pursuit the following methods were used: a color threshold, a value threshold, and the time variation in color. All methods provided some indication of the liquid region but none were able to capture the full liquid boundary as obtained by the Mie-scatter results. Funding from NSF REU site Grant EEC 1358991 is greatly appreciated.

  7. Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi B. R.

    2010-01-01

    Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

  8. Quantum Interference Phenomena and Novel Switching in Split Gate High Electron Mobility Transistors.

    NASA Astrophysics Data System (ADS)

    Wu, Jong-Ching

    Nanometer scales electronic channels with and without a discontinuity were made in modulation-doped AlGaAs/GaAs heterojunctions using a split-gate technique. Quantum interference phenomena in an electron cavity, and fast switching behavior due to hot electron effects in a lateral double potential barrier structure were explored. First, one-dimensional channels with a double bend discontinuity were examined in the mK temperature range. Low-field ac-conductance measurements have evidenced quantum wave guide effects: resonant features were observed in the one-dimensional conductance plateaus in which the number of peaks was directly related to the geometry of the double bend. Temperature and magnetic field studies, along with a standing wave model have provided a better understanding of quantum interference phenomena in electron wave guide and cavity structures. Secondly, a structure containing two cascaded double bend discontinuities was studied. The structure behaves as a constricted cavity coupling two point-contacts, in which the depletion by the split gate was used to form and control the lateral double potential barriers. The low temperature source-drain characteristics exhibited a pronounced S-shaped negative differential conductance that can be attributed to a nonlinear electron temperature effect along the conducting path. The data presented show two types of conducting state: electron tunneling in the off state and hot electron conduction (thermionic emission) in the on state. The estimated switching speed of the device could be as fast as 5 ps due to short transit time.

  9. Quantum interference phenomena and novel switching in split gate high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Wu, Jong-Ching

    Nanometer scale electronic channels with and without a discontinuity were made in modulation-doped AlGaAs/GaAs heterojunctions using a split gate technique. Quantum interference phenomena in an electron cavity and fast switching behavior due to hot electron effects in a lateral double potential barrier structure were explored. First, one dimensional channels with a double bend discontinuity were examined in the mK temperature range. Low-field ac-conductance measurements have evidenced quantum waveguide effects: resonant features were observed in the one dimensional conductance plateaus in which the number of peaks was directly related to the geometry of the double bend. Temperature and magnetic field studies, along with a standing wave model, have provided a better understanding of quantum interference phenomena in electron wave guide and cavity structures. Secondly, a structure containing two cascaded double bend discontinuities was studied. The structure behaves as a constricted cavity coupling two point-contacts, in which the depletion by the split gate was used to form and control the lateral double potential barriers. The low temperature source-drain characteristics exhibited a pronounced S-shaped negative differential conductance that can be attributed to a nonlinear electron temperature effect along the conducting path. The data presented show two types of conducting state: electron tunneling in the off state and hot electron conduction (thermionic emission) in the on state. The estimated switching speed of the device could be as fast as 5 ps due to short transit time.

  10. Novel Applications of High Speed Optical-Injection Locked Lasers

    DTIC Science & Technology

    2010-07-31

    frequency response of high speed phototransistors . We have also shown the OIL lasers can significantly extend the reach of optical communications, to I20km...speed InP Heterojunction PhotoTransistors (HPTs). 1 HPT test wafers have been designed and taped out, consisting of single ended HPTs... phototransistors . Light transmitted by the lens fiber and waveguide into the base of the transistor modulates the base current in the device. The

  11. Ultra high speed image processing techniques. [electronic packaging techniques

    NASA Technical Reports Server (NTRS)

    Anthony, T.; Hoeschele, D. F.; Connery, R.; Ehland, J.; Billings, J.

    1981-01-01

    Packaging techniques for ultra high speed image processing were developed. These techniques involve the development of a signal feedthrough technique through LSI/VLSI sapphire substrates. This allows the stacking of LSI/VLSI circuit substrates in a 3 dimensional package with greatly reduced length of interconnecting lines between the LSI/VLSI circuits. The reduced parasitic capacitances results in higher LSI/VLSI computational speeds at significantly reduced power consumption levels.

  12. Quality of service on high-speed data networks

    NASA Astrophysics Data System (ADS)

    Barbero, Ezio; Antonelli, Ferruccio

    1995-02-01

    Since the beginning of this century the issue of `quality' has been gaining increasing importance in a number of fields of human activities. For telecommunication services, too, the quality perceived by customers has been taken into account early on as an issue of strategic importance. Whilst for telephony the Quality of Service (QoS) has been already investigated and identified in terms of parameters and related test methodology, the situation for high speed data services (i.e. CBDS/SMDS, Frame Relay, etc.), provided by means of high speed network based on Asynchronous Transfer Moe (ATM) or Metropolitan Area Network technologies, can still be considered `under study'. There is a death of experience not only in terms of measurement instruments and procedures, but also in terms of knowledge of the relationship between the QoS provided at a network level and the quality perceived by the user on his or her terminal. The complexity of the equipment involved in setting up an end-to-end solution based on high speed data communications makes the problems of knowledge and supply of quality very hard to solve. Starting from the experience gained in carrying out high- speed network field trials based on Metropolitan Area Networks and, more recently, on ATM technology, the paper mainly deals with the problem of defining, measuring and then offering a specific QoS. First, the issue of what the user expects from the `high-speed network' is addressed. This analysis is carried out trying to gather what is peculiar to high-speed data communications from the user standpoint. Next, the focus is on how to cope with the requirements due to users' expectations, while carefully considering the basic principles of quality. Finally, a solution is proposed, starting from the experience gained from high speed networks installed in Italy.

  13. Material requirements for the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.; Hecht, Ralph J.; Johnson, Andrew M.

    1993-01-01

    Under NASA-sponsored High Speed Research (HSR) programs, the materials and processing requirements have been identified for overcoming the environmental and economic barriers of the next generation High Speed Civil Transport (HSCT) propulsion system. The long (2 to 5 hours) supersonic cruise portion of the HSCT cycle will place additional durability requirements on all hot section engine components. Low emissions combustor designs will require high temperature ceramic matrix composite liners to meet an emission goal of less than 5g NO(x) per Kg fuel burned. Large axisymmetric and two-dimensional exhaust nozzle designs are now under development to meet or exceed FAR 36 Stage III noise requirements, and will require lightweight, high temperature metallic, intermetallic, and ceramic matrix composites to reduce nozzle weight and meet structural and acoustic component performance goals. This paper describes and discusses the turbomachinery, combustor, and exhaust nozzle requirements of the High Speed Civil Transport propulsion system.

  14. Material requirements for the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.; Hecht, Ralph J.; Johnson, Andrew M.

    1993-01-01

    Under NASA-sponsored High Speed Research (HSR) programs, the materials and processing requirements have been identified for overcoming the environmental and economic barriers of the next generation High Speed Civil Transport (HSCT) propulsion system. The long (2 to 5 hours) supersonic cruise portion of the HSCT cycle will place additional durability requirements on all hot section engine components. Low emissions combustor designs will require high temperature ceramic matrix composite liners to meet an emission goal of less than 5g NO(x) per Kg fuel burned. Large axisymmetric and two-dimensional exhaust nozzle designs are now under development to meet or exceed FAR 36 Stage III noise requirements, and will require lightweight, high temperature metallic, intermetallic, and ceramic matrix composites to reduce nozzle weight and meet structural and acoustic component performance goals. This paper describes and discusses the turbomachinery, combustor, and exhaust nozzle requirements of the High Speed Civil Transport propulsion system.

  15. Robust emergent climate phenomena associated with the high-sensitivity tail.

    SciTech Connect

    Backus, George A.; Levy, Michael Nathan; Boslough, Mark Bruce Elrick

    2010-12-01

    Because the potential effects of climate change are more severe than had previously been thought, increasing focus on uncertainty quantification is required for risk assessment needed by policy makers. Current scientific efforts focus almost exclusively on establishing best estimates of future climate change. However, the greatest consequences occur in the extreme tail of the probability density functions for climate sensitivity (the 'high-sensitivity tail'). To this end, we are exploring the impacts of newly postulated, highly uncertain, but high-consequence physical mechanisms to better establish the climate change risk. We define consequence in terms of dramatic change in physical conditions and in the resulting socioeconomic impact (hence, risk) on populations. Although we are developing generally applicable risk assessment methods, we have focused our initial efforts on uncertainty and risk analyses for the Arctic region. Instead of focusing on best estimates, requiring many years of model parameterization development and evaluation, we are focusing on robust emergent phenomena (those that are not necessarily intuitive and are insensitive to assumptions, subgrid-parameterizations, and tunings). For many physical systems, under-resolved models fail to generate such phenomena, which only develop when model resolution is sufficiently high. Our ultimate goal is to discover the patterns of emergent climate precursors (those that cannot be predicted with lower-resolution models) that can be used as a 'sensitivity fingerprint' and make recommendations for a climate early warning system that would use satellites and sensor arrays to look for the various predicted high-sensitivity signatures. Our initial simulations are focused on the Arctic region, where underpredicted phenomena such as rapid loss of sea ice are already emerging, and because of major geopolitical implications associated with increasing Arctic accessibility to natural resources, shipping routes, and

  16. Ultra-high-speed spectropolarimeter based on photoelastic modulator.

    PubMed

    Zhang, Rui; Li, Kewu; Chen, Yuanyuan; Wen, Tingdun; Zhang, Minjuan; Wang, Yaoli; Xue, Peng; Wang, Zhibin

    2016-10-20

    Combined with the advantages of photoelastic modulator (PEM) ultra-high-speed modulation, this paper presents a method of ultra-high-speed spectropolarimeter based on PEM. The method provides the necessary measuring instruments for ultra-high-speed polarization spectroscopy. The main idea of this method is that an intensity modulator consisting of two retarders is placed before the PEM. The incident light under test goes through two retarders to the PEM. The interference signals are obtained by the PEM modulation. The different Stokes element interference signals are modulated by the PEM at different positions of the optical path difference. This method realizes the separation of Stokes element interference signals. The interference signals corresponding to each element are extracted, and the incident light Stokes element spectra can be obtained from the Fourier transforms of the interference signals. The modulation frequency of the PEM is high (tens to hundreds of kilohertz), so this method can realize ultra-high-speed full polarization spectroscopy. A prototype ultra-high-speed spectropolarimeter based on PEM was designed and tested. If the single-sided Fourier transformation is used, the single-sided interferogram scanning time is approximately 5 μs (i.e., the prototype is capable of scanning 20,000 interferograms per second). Polychromatic light polarization spectroscopy is measured by the prototype. The experimental results show that the average error of the prototype is less than 0.03.

  17. Assessment of rural soundscapes with high-speed train noise.

    PubMed

    Lee, Pyoung Jik; Hong, Joo Young; Jeon, Jin Yong

    2014-06-01

    In the present study, rural soundscapes with high-speed train noise were assessed through laboratory experiments. A total of ten sites with varying landscape metrics were chosen for audio-visual recording. The acoustical characteristics of the high-speed train noise were analyzed using various noise level indices. Landscape metrics such as the percentage of natural features (NF) and Shannon's diversity index (SHDI) were adopted to evaluate the landscape features of the ten sites. Laboratory experiments were then performed with 20 well-trained listeners to investigate the perception of high-speed train noise in rural areas. The experiments consisted of three parts: 1) visual-only condition, 2) audio-only condition, and 3) combined audio-visual condition. The results showed that subjects' preference for visual images was significantly related to NF, the number of land types, and the A-weighted equivalent sound pressure level (LAeq). In addition, the visual images significantly influenced the noise annoyance, and LAeq and NF were the dominant factors affecting the annoyance from high-speed train noise in the combined audio-visual condition. In addition, Zwicker's loudness (N) was highly correlated with the annoyance from high-speed train noise in both the audio-only and audio-visual conditions.

  18. High prevalence of false-positive plateau phenomena during VO2max testing in adolescents.

    PubMed

    Beltrami, Fernando G; Wong, Del P; Noakes, Timothy D

    2014-09-01

    It is believed that a plateau in oxygen consumption (VO2) at the end of an incremental exercise test identifies the upper limits of cardiovascular capacity. We investigated how different criteria influence the frequency with which the "plateau phenomenon" is detected and the prevalence at which "false" plateau phenomena occurs during sub-maximal exercise. Cross-sectional. Six different criteria with 3 different sampling intervals each were used to identify the "plateau phenomenon" from a single data set comprising 63 incremental exercise tests along with secondary criteria based on target heart rate (HR) and respiratory exchange ratio (RER). A single criterion from the original 18 (HALF) was also used to detect the incidence of any plateau phenomena during each test. The plateau phenomenon was detected in 16-82% of the tests depending on the criteria used, mostly as a result of the different sampling intervals. HALF identified 103 "plateau phenomena" but 73 (70.9%) of these occurred during sub-maximal exercise and so were "false". "False" plateaus were verified by at least one secondary criterion in 27% of cases. Participants reached the HR and RER targets after 83.6 ± 11.7% and 81.9 ± 18.1% of total test duration, respectively. The wide range in the percentage of plateau phenomena detected by different criteria plus the high rate (71%) of "false" plateau during sub-maximal exercise could indicate that this phenomenon is a calculation artifact rather than an indicator of true physiological events. Secondary criteria can be reached early in exercise and often identify "false" plateau phenomena as "true". Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  19. High-speed quantitative phase imaging of dynamic thermal deformation in laser irradiated films

    NASA Astrophysics Data System (ADS)

    Taylor, Lucas N.; Brown, Andrew K.; Olson, Kyle D.; Talghader, Joseph J.

    2015-11-01

    We present a technique for high-speed imaging of the dynamic thermal deformation of transparent substrates under high-power laser irradiation. Traditional thermal sensor arrays are not fast enough to capture thermal decay events. Our system adapts a Mach-Zender interferometer, along with a high-speed camera to capture phase images on sub-millisecond time-scales. These phase images are related to temperature by thermal expansion effects and by the change of refractive index with temperature. High power continuous-wave and long-pulse laser damage often hinges on thermal phenomena rather than the field-induced effects of ultra-short pulse lasers. Our system was able to measure such phenomena. We were able to record 2D videos of 1 ms thermal deformation waves, with 6 frames per wave, from a 100 ns, 10 mJ Q-switched Nd:YAG laser incident on a yttria-coated glass slide. We recorded thermal deformation waves with peak temperatures on the order of 100 degrees Celsius during non-destructive testing.

  20. HDR {sup 192}Ir source speed measurements using a high speed video camera

    SciTech Connect

    Fonseca, Gabriel P.; Rubo, Rodrigo A.; Sales, Camila P. de; Verhaegen, Frank

    2015-01-15

    Purpose: The dose delivered with a HDR {sup 192}Ir afterloader can be separated into a dwell component, and a transit component resulting from the source movement. The transit component is directly dependent on the source speed profile and it is the goal of this study to measure accurate source speed profiles. Methods: A high speed video camera was used to record the movement of a {sup 192}Ir source (Nucletron, an Elekta company, Stockholm, Sweden) for interdwell distances of 0.25–5 cm with dwell times of 0.1, 1, and 2 s. Transit dose distributions were calculated using a Monte Carlo code simulating the source movement. Results: The source stops at each dwell position oscillating around the desired position for a duration up to (0.026 ± 0.005) s. The source speed profile shows variations between 0 and 81 cm/s with average speed of ∼33 cm/s for most of the interdwell distances. The source stops for up to (0.005 ± 0.001) s at nonprogrammed positions in between two programmed dwell positions. The dwell time correction applied by the manufacturer compensates the transit dose between the dwell positions leading to a maximum overdose of 41 mGy for the considered cases and assuming an air-kerma strength of 48 000 U. The transit dose component is not uniformly distributed leading to over and underdoses, which is within 1.4% for commonly prescribed doses (3–10 Gy). Conclusions: The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases.

  1. High Energy Phenomena on the Sun. [conference on solar activity effects and solar radiation

    NASA Technical Reports Server (NTRS)

    Ramaty, R. (Editor); Stone, R. G. (Editor)

    1973-01-01

    The proceedings of a symposium of high energy phenomena on the sun are presented. The subjects discussed include the following: (1) flare theories and optical observations, (2) microwave and hard X-ray observations, (3) ultraviolet and soft X-ray emissions, (4) nuclear reactions in solar flares, (5) energetic particles from the sun, (6) magnetic fields and particle storage, and (7) radio emissions in the corona and interplanetary space.

  2. Jet production and high p/sub T/ phenomena in photon-photon reactions

    SciTech Connect

    Wermes, N.

    1983-05-01

    The status of experimental investigations of high p/sub T/ phenomena and jet production in photon-photon collisions is reviewed. Taking the challenging questions on hard scattering processes in ..gamma gamma.. reactions as a guide, the experimental approach to these questions is summarized. Results from the PETRA experiments CELLO, JADE, PLUTO, and TASSO are presented including preliminary results on the Q/sup 2/-dependence of jet cross sections. Experimental limitations and background problems are discussed. 36 references.

  3. High speed commercial transport fuels considerations and research needs

    NASA Technical Reports Server (NTRS)

    Lee, C. M.; Niedzwiecki, R. W.

    1989-01-01

    NASA is currently evaluating the potential of incorporating High Speed Civil Transport (HSCT) aircraft in the commercial fleet in the beginning of the 21st century. NASA sponsored HSCT enabling studies currently underway with airframers and engine manufacturers, are addressing a broad range of technical, environmental, economic, and related issues. Supersonic cruise speeds for these aircraft were originally focused in the Mach 2 to 5 range. At these flight speeds, both jet fuels and liquid methane were considered potential fuel candidates. For the year 2000 to 2010, cruise Mach numbers of 2 to 3+ are projected for aircraft fuel with thermally stable liquid jet fuels. For 2015 and beyond, liquid methane fueled aircraft cruising at Mach numbers of 4+ may be viable candidates. Operation at supersonic speeds will be much more severe than those encountered at subsonic flight. One of the most critical problems is the potential deterioration of the fuel due to the high temperature environment. HSCT fuels will not only be required to provide the energy necessary for flight, but will also be subject to aerodynamic heating and, will be required to serve as the primary heat sink for cooling the engine and airframe. To define fuel problems for high speed flight, a fuels workshop was conducted at NASA Lewis Research Center. The purpose of the workshop was to gather experts on aviation fuels, airframe fuel systems, airport infrastructure, and combustion systems to discuss high speed fuel alternatives, fuel supply scenarios, increased thermal stability approaches and measurements, safety considerations, and to provide directional guidance for future R and D efforts. Subsequent follow-up studies defined airport infrastructure impacts of high speed fuel candidates. The results of these activities are summarized. In addition, an initial case study using modified in-house refinery simulation model Gordian code (1) is briefly discussed. This code can be used to simulate different

  4. The application of high-speed digital image correlation.

    SciTech Connect

    Reu, Phillip L.; Miller, Timothy J.

    2008-02-01

    Digital image correlation (DIC) is a method of using digital images to calculate two-dimensional displacement and deformation or for stereo systems three-dimensional shape, displacement, and deformation. While almost any imaging system can be used with DIC, there are some important challenges when working with the technique in high- and ultra-high-speed applications. This article discusses three of these challenges: camera sensor technology, camera frame rate, and camera motion mitigation. Potential solutions are treated via three demonstration experiments showing the successful application of high-speed DIC for dynamic events. The application and practice of DIC at high speeds, rather than the experimental results themselves, provide the main thrust of the discussion.

  5. Thermal Behavior of High-Speed Helical Gear Trains Investigated

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.

    2003-01-01

    High-speed and heavily loaded gearing are commonplace in the rotorcraft systems employed in helicopter and tiltrotor transmissions. The components are expected to deliver high power from the gas turbine engines to the high-torque, low-speed rotor, reducing the shaft rotational speed in the range of 25:1 to 100:1. These components are designed for high power-to-weight ratios, thus the components are fabricated as light as possible with the best materials and processing to transmit the required torque and carry the resultant loads without compromising the reliability of the drive system. This is a difficult task that is meticulously analyzed and thoroughly tested experimentally prior to being applied on a new or redesigned aircraft.

  6. Custom ASIC development for high-speed Viterbi decoding

    NASA Astrophysics Data System (ADS)

    Miller, S. P.; Becker, N.; Johnson, P. N.

    A high-speed, emitter-coupled logic (ECL) gate array which greatly facilitates the implementation of very-high-speed Viterbi algorithm processors has been developed. These high-speed Viterbi decoders were incorporated into two bandwidth-efficient, jointly optimized coded modulation systems with baseband information rates of 140 and 200 Mb/s. The 200-Mb/s system was developed for NASA under the advanced modulation technology development program. The octal phase shift keying (8PSK) modulation technique used in these systems requires symbol rates of 60 and 75 Msymbol/s. The gate array device also has the potential for use in similar systems with symbol rates in excess of 100 Msymbol/s. Some details of the coded modulation systems that require the implementation of high-speed Viterbi processors are provided to demonstrate current practical applications and the need for this processing capability. The specific gate array design is described in conjunction with the performance goals and measured parameters of the completed device. Performance measurements obtained from high-speed coded modulation systems that use the gate array are also presented to show the performance obtained.

  7. High-speed GaInNAs laser diodes

    NASA Astrophysics Data System (ADS)

    Kondow, Masahiko; Nakahara, Kouji; Fujisaki, S.; Tanaka, Shigehisa; Kudo, M.; Taniguchi, Tadashi; Terano, A.; Uchiyama, H.

    2004-05-01

    The explosive growth of Internet/intranet traffic has created a strong demand for cost-effective high-speed light-sources to be used in local access networks and data links. The frequency of relaxation oscillation (fr) is a major factor that restricts the high-speed operation of laser diodes. To achieve a high fr, the material of an active layer should have a large differential gain. By using GaInNAs, very deep quantum wells, especially in the conduction band can be formed. Deep quantum wells bring a large differential gain. In this paper, we show how GaInNAs lasers can be applied in this application

  8. Femtoliter-scale patterning by high-speed, highly scaled inverse gravure printing.

    PubMed

    Kitsomboonloha, Rungrot; Morris, S J S; Rong, Xiaoying; Subramanian, Vivek

    2012-12-04

    Pattern printing techniques have advanced rapidly in the past decade, driven by their potential applications in printed electronics. Several printing techniques have realized printed features of 10 μm or smaller, but unfortunately, they suffer from disadvantages that prevent their deployment in real applications; in particular, process throughput is a significant concern. Direct gravure printing is promising in this regard. Gravure printing delivers high throughput and has a proven history of being manufacturing worthy. Unfortunately, it suffers from scalability challenges because of limitations in roll manufacturing and limited understanding of the relevant printing mechanisms. Gravure printing involves interactions between the ink, the patterned cylinder master, the doctor blade that wipes excess ink, and the substrate to which the pattern is transferred. As gravure-printed features are scaled, the associated complexities are increased, and a detailed study of the various processes involved is lacking. In this work, we report on various gravure-related fluidic mechanisms using a novel highly scaled inverse direct gravure printer. The printer allows the overall pattern formation process to be studied in detail by separating the entire printing process into three sequential steps: filling, wiping, and transferring. We found that pattern formation by highly scaled gravure printing is governed by the wettability of the ink to the printing plate, doctor blade, and substrate. These individual functions are linked by the apparent capillary number (Ca); the printed volume fraction (φ(p)) of a feature can be constructed by incorporating these basis functions. By relating Ca and φ(p), an optimized operating point can be specified, and the associated limiting phenomena can be identified. We used this relationship to find the optimized ink viscosity and printing speed to achieve printed polymer lines and line spacings as small as 2 μm at printing speeds as high as ∼1 m/s.

  9. Unsteady Flow Simulation of High-speed Turbopumps

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Kwak, dochan; Chan, William; Housman, Jeffrey A.

    2006-01-01

    Computation of high-speed hydrodynamics requires high-fidelity simulation to resolve flow features involving transient flow, cavitation, tip vortex and multiple scales of unsteady fluctuations. One example of this type in aerospace is related to liquid-fueled rocket turbopump. Rocket turbopumps operate under severe conditions at very high rotational speeds typically at thousands of rpm. For example, the Shuttle orbiter low-pressure-fuel-turbopump creates transient flow features associated with reverse flows, tip clearance effects, secondary flows, vortex shedding, junction flows, and cavitation effects. Flow unsteadiness originating from the orbiter Low-Pressure-Fuel-Turbopump (LPFTP) inducer is one of the major contributors to the high frequency cyclic loading that results in high cycle fatigue damage to the flow liners just upstream of the LPFTP. The reverse flow generated at the tip of the inducer blades travels upstream and interacts with the bellows cavity. Simulation procedure for this type high-speed hydrodynamic problems requires a method for quantifying multi-scale and multi-phase flow as well as an efficient high-end computing strategy. The current paper presents a high-fidelity computational procedure for unsteady hydrodynamic problems using a high-speed liquid-fueled rocket turbopump.

  10. Low-cost digital visualization and high-speed tracking of supersonic shockwaves

    NASA Astrophysics Data System (ADS)

    Bryanston-Cross, Peter J.; Skeen, Andrew J.; Timmerman, Brenda H.; Dunkley, P.; Paduano, James D.; Guenette, G. R., Jr.

    2003-11-01

    A low-cost and low-maintenance digital focused shadowgraph flow visualization system has been developed to provide fast diagnostics of rapidly changing phenomena in supersonic flows. The system is particularly designed for tracking shock positions in a supersonic inlet, enabling high-speed active shock control. It is based on a low-cost, high-intensity white LED light source, which can be flashed with microsecond pulses enabling freeze-frame imaging of constant illumination quality. The system features three modes of operation: (1) High-resolution digital still frames and sequences (1280 x 1024, 2fps), (2) High-resolution digital frames and sequences showing spatial-temporal variation in flow field (1280 x 1024, 12 fps), (3) Adjustable windowed digital frames at reduced resolution, but at high frame rates (980 fps at 1280 x 8 pixel viewing area). The three modes of operation allow high-speed tracking of flow features such as moving of shock waves (up to 980 Hz) as well as overall instantaneous views of the flow. Furthermore, it allows direct identification of areas where high-speed changes occur. The positional shock data can be transmitted directly to a shock-stabilizing control system. Results are presented of the unsteady flow generated by an aspirated cone-shaped nozzle in a supersonic flow in the supersonic wind tunnel of the MIT Gas Turbine Laboratory.

  11. Differences in energy expenditure during high-speed versus standard-speed yoga: A randomized sequence crossover trial.

    PubMed

    Potiaumpai, Melanie; Martins, Maria Carolina Massoni; Rodriguez, Roberto; Mooney, Kiersten; Signorile, Joseph F

    2016-12-01

    To compare energy expenditure and volume of oxygen consumption and carbon dioxide production during a high-speed yoga and a standard-speed yoga program. Randomized repeated measures controlled trial. A laboratory of neuromuscular research and active aging. Sun-Salutation B was performed, for eight minutes, at a high speed versus and a standard-speed separately while oxygen consumption was recorded. Caloric expenditure was calculated using volume of oxygen consumption and carbon dioxide production. Difference in energy expenditure (kcal) of HSY and SSY. Significant differences were observed in energy expenditure between yoga speeds with high-speed yoga producing significantly higher energy expenditure than standard-speed yoga (MD=18.55, SE=1.86, p<0.01). Significant differences were also seen between high-speed and standard-speed yoga for volume of oxygen consumed and carbon dioxide produced. High-speed yoga results in a significantly greater caloric expenditure than standard-speed yoga. High-speed yoga may be an effective alternative program for those targeting cardiometabolic markers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. High-speed cylindrical collapse of two perfect fluids

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Ahmad, Zahid

    2007-09-01

    In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using the high-speed approximation scheme. There arise two cases, i.e., bounded and vanishing of the ratios of the pressures with densities of two fluids given by c s , d s . It is shown that the high-speed approximation scheme breaks down by non-zero pressures p 1, p 2 when c s , d s are bounded below by some positive constants. The failure of the high-speed approximation scheme at some particular time of the gravitational collapse suggests the uncertainty on the evolution at and after this time. In the bounded case, the naked singularity formation seems to be impossible for the cylindrical two perfect fluids. For the vanishing case, if a linear equation of state is used, the high-speed collapse does not break down by the effects of the pressures and consequently a naked singularity forms. This work provides the generalisation of the results already given by Nakao and Morisawa (Prog Theor Phys 113:73, 2005) for the perfect fluid.

  13. Surface roughness analysis of hardened steel after high-speed milling.

    PubMed

    Twardowski, Paweł; Wojciechowski, Szymon; Wieczorowski, Michał; Mathia, Thomas

    2011-01-01

    The work refers to analysis of various factors affecting surface roughness after end milling of hardened steel in high-speed milling (HSM) conditions. Investigations of milling parameters (cutting speed v(c) , axial depth of cut a(p) ) and the process dynamics that influence machined surface roughness were presented, and a surface roughness model, including cutter displacements, was elaborated. The work also involved analysis of surface profile charts from the point of view of vibrations and cutting force components. The research showed that theoretic surface roughness resulting from the kinematic-geometric projection of cutting edge in the workpiece is significantly different from the reality. The dominant factor in the research was not feed per tooth f(z) (according to the theoretical model) but dynamical phenomena and feed per revolution f.

  14. High speed tapping mode atomic force microscopy in liquid using an insulated piezoelectric cantilever

    NASA Astrophysics Data System (ADS)

    Rogers, B.; Sulchek, T.; Murray, K.; York, D.; Jones, M.; Manning, L.; Malekos, S.; Beneschott, B.; Adams, J. D.; Cavazos, H.; Minne, S. C.

    2003-11-01

    Quicker imaging times for tapping mode atomic force microscopy in liquid could provide a real-time imaging tool for studying dynamic phenomena in physiological conditions. We demonstrate faster imaging speed using microcantilevers with integrated piezoelectric actuators. The exposed electric components of the cantilever necessitate an insulation scheme for use in liquid; three coating schemes have been tested. Preliminary tapping mode images have been taken using the insulated microactuator to simultaneously vibrate and actuate the cantilever over topographical features in liquid, including a high speed image of steps on a mica surface in water and an image of two e coli bacteria taken in saline solution at 75.5 μm/s, a threefold improvement in bandwidth versus conventional piezotube actuators.

  15. Fiber laser for high speed laser transfer printing

    NASA Astrophysics Data System (ADS)

    Petkovšek, Rok; Novak, Vid; Agrež, Vid

    2017-01-01

    High speed industrial laser transfer printing requires high power lasers that can deliver pulses on demand and having arbitrary pulse duration in range of few nanoseconds to milliseconds or more. A special kind of MOPA fiber laser is presented using wavelength multiplexing to achieve pulses on demand with minimal transients. The system is further tested in printing application.

  16. Geometric Acoustics in High-Speed Boundary Layers

    NASA Astrophysics Data System (ADS)

    Parziale, N. J.; Shepherd, J. E.; Hornung, H. G.

    A key mechanism responsible for the instability of high-speed boundary layers are the high-frequency modes discovered by Mack [1]. These modes are primarily acoustic in nature, are always present if the edge Mach number is sufficiently large, and are the dominant instability mechanism when the wall temperature is sufficiently low compared to the recovery temperature.

  17. Noise in the passenger cars of high-speed trains.

    PubMed

    Hong, Joo Young; Cha, Yongwon; Jeon, Jin Yong

    2015-12-01

    The aim of this study is to investigate the effects of both room acoustic conditions and spectral characteristics of noises on acoustic discomfort in a high-speed train's passenger car. Measurement of interior noises in a high-speed train was performed when the train was operating at speeds of 100 km/h and 300 km/h. Acoustic discomfort caused by interior noises was evaluated by paired comparison methods based on the variation of reverberation time (RT) in a passenger car and the spectral differences in interior noises. The effect of RT on acoustic discomfort was not significant, whereas acoustic discomfort significantly varied depending on spectral differences in noise. Acoustic discomfort increased with increment of the sound pressure level (SPL) ratio at high frequencies, and variation in high-frequency noise components were described using sharpness. Just noticeable differences of SPL with low- and high-frequency components were determined to be 3.7 and 2.9 dB, respectively. This indicates that subjects were more sensitive to differences in SPLs at the high-frequency range than differences at the low-frequency range. These results support that, for interior noises, reduction in SPLs at high frequencies would significantly contribute to improved acoustic quality in passenger cars of high-speed trains.

  18. A novel two-axis parallel-kinematic high-speed piezoelectric scanner for atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Alunda, Bernard Ouma; Lee, Yong Joong; Park, Soyeun

    2016-09-01

    High-speed atomic force microscopy permits the capture of static, as well as the dynamic, processes present in various physical phenomena. Unlike visualizing static processes, capture of dynamic processes requires high-speed scanning in all three dimensions. Despite the recent increased interest in high-speed atomic force microscopy, relatively few reports concerning piezoelectric actuator-driven scanners for high-speed scanning have been published. In this paper, we propose a novel design for a high-speed two-dimensional piezoelectric scanner unit by combining the positive features developed from works published in the literature. The proposed design ensures high vertical stiffness by utilizing compliant double-hinged flexure that minimizes cross-coupling and parasitic motions. Any high-speed scanner design requires a compromise between the two main competing parameters: maximum scan size and speed. The performance of the proposed scanner was evaluated by using numerical simulations with finite element analyses in terms of the mechanical resonance frequencies and the scan range. Finally, the results from the numerical simulations are compared with the experimental measurements.

  19. Tank Tests of Two Floats for High-speed Seaplanes

    NASA Technical Reports Server (NTRS)

    Bell, Joe W

    1933-01-01

    At the request of the Bureau of Aeronautics, Navy Department, a study of the design of floats especially suitable for use on high-speed seaplanes was undertaken in the N.A.C.A. tank. This note give the results obtained in tests of one-quarter full-size models of two floats for high-speed seaplanes. One was a float similar to that used on the Macchi high-speed seaplane which competed in the 1926 Schneider Trophy races, and the other a float designed at the N.A.C.A. tank in an attempt to improve on the water performance of the Macchi float. The model of the latter showed considerably better water performance than the model of the Macchi float.

  20. LIHSP: Lucky Imaging And High Speed Photometry at LCOGT

    NASA Astrophysics Data System (ADS)

    Bianco, Federica; Street, R.; Tsapras, Y.; Shporer, A.; Tufts, J.; Lister, T.; Gomez, E.; Rosing, W.; Brown, T.; LCOGT Team

    2011-05-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) is building a world wide telescope network with an emphasis on time domain astronomy. The final LCOGT network will have at least 40 telescopes in at least 7 sites around the world to continuously cover the dark sky in both hemispheres: two 2.0m telescopes, already available on Haleakala - HI, USA (FTN), and Siding Spring - Australia (FTS), roughly fifteen 1m, and twenty-five 0.4m telescopes now in various stages of construction and commissioning. We are integrating our telescopes with high speed EMCCD cameras to provide high speed photometry as well as lucky imaging capabilities. Here we present our first generation high speed solutions, already installed at FTN and FTS and currently being integrated into our robotic system. Similar facilities are being fabricated for the 0.4m network, and designed for the 1m network.

  1. Toward a Molecular-Based Understanding of High-Temperature Solvation Phenomena in Aqueous Electrolyte Solutions

    SciTech Connect

    Chialvo, A.A.; Cummings, P.T.; Kusalik, P.G.; Simonson, J.M.

    1999-10-30

    The theoretical treatment of the solvation phenomenon of simple ions in aqueous solutions has been rather difficult, despite the apparent simplicity of the system. Long-range solvent-screened electrostatic interactions, coupled to the large variation (with state conditions) of the dielectric permittivity of water, give rise to a variety of rather complex solvation phenomena including dielectric saturation, electrostriction, and ion association. Notably, ion solvation in high-temperature/pressure aqueous solutions plays a leading role in hydrothermal chemistry, such as in the natural formation of ore deposits, the corrosion in boilers and reactors, and in high-temperature microbiology. Tremendous effort has been invested in the study of hydrothermal solutions to determine their thermodynamic, transport, and spectroscopic properties with the goal of elucidating the solute-solvent and solute-solute interactions over a wide range of state conditions. It is precisely at these conditions where our understanding and predictive capabilities are most precarious, in part, as a result of the coexistence of processes with two rather different length scales, i.e., short-ranged (solvation) and long-ranged (compressibility-driven) phenomena (Chialvo and Cummings 1994a). The latter feature makes hydrothermal systems extremely challenging to model, unless we are able to isolate the (compressibility-driven) propagation of the density perturbation from the (solvation-related) finite-density perturbation phenomena (Chialvo and Cummings 1995a).

  2. Handling qualities of the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Solies, U. Peter

    1994-01-01

    The low speed handling qualities of a High Speed Civil Transport class aircraft have been investigated by using data of the former Advanced Supersonic Transport (AST) 105. The operation of such vehicles in the airport terminal area is characterized by 'backside' performance. Main objectives of this research effort were: (Q) determination of the nature and magnitude of the speed instability associated with the backside of the thrust required curve; (2) confirmation of the validity of existing MIL-SPEC handling qualities criteria; (3) safety of operation of the vehicle in the event of autothrottle failure; and (4) correlation of required engine responsiveness with level of speed instability. Preliminary findings comprise the following: (1) The critical velocity for speed instability was determined to be 196 knots, well above the projected approach speed of 155 knots. This puts the vehicle far on the backside of its thrust required curve. While the aircraft can be configured to have static and dynamic stability at this trim point, a significant speed instability emerges, if a pilot or autopilot attempts flight path control with elevator and/or canard control surfaces only. This requires a properly configured autothrottle and/or variable aerodynamic drag devices which can provide speed stability; (2) An AST 105 type vehicle meets MIL-SPEC criteria only in part. While the damping criteria for phugoid and short period motion are met easily, the AST 105 falls short of the required minimum short period frequency, meaning that the HSCT is too sluggish in pitch to meet the military criteria. Obviously the military specification do not consider a vehicle with such high pitch inertia. With regard to speed stability and flight path stability criteria, the vehicle meets levels 2 and 3 of the military requirements, indicating that it would be landed safety with manual controls in case of an autothrottle failure, even though the pilot workload would be high; and (3) This requires

  3. Ultra-high-speed bionanoscope for cell and microbe imaging

    NASA Astrophysics Data System (ADS)

    Etoh, T. Goji; Vo Le, Cuong; Kawano, Hiroyuki; Ishikawa, Ikuko; Miyawaki, Atshushi; Dao, Vu T. S.; Nguyen, Hoang Dung; Yokoi, Sayoko; Yoshida, Shigeru; Nakano, Hitoshi; Takehara, Kohsei; Saito, Yoshiharu

    2008-11-01

    We are developing an ultra-high-sensitivity and ultra-high-speed imaging system for bioscience, mainly for imaging of microbes with visible light and cells with fluorescence emission. Scarcity of photons is the most serious problem in applications of high-speed imaging to the scientific field. To overcome the problem, the system integrates new technologies consisting of (1) an ultra-high-speed video camera with sub-ten-photon sensitivity with the frame rate of more than 1 mega frames per second, (2) a microscope with highly efficient use of light applicable to various unstained and fluorescence cell observations, and (3) very powerful long-pulse-strobe Xenon lights and lasers for microscopes. Various auxiliary technologies to support utilization of the system are also being developed. One example of them is an efficient video trigger system, which detects a weak signal of a sudden change in a frame under ultra-high-speed imaging by canceling high-frequency fluctuation of illumination light. This paper outlines the system with its preliminary evaluation results.

  4. Advanced superposition methods for high speed turbopump vibration analysis

    NASA Technical Reports Server (NTRS)

    Nielson, C. E.; Campany, A. D.

    1981-01-01

    The small, high pressure Mark 48 liquid hydrogen turbopump was analyzed and dynamically tested to determine the cause of high speed vibration at an operating speed of 92,400 rpm. This approaches the design point operating speed of 95,000 rpm. The initial dynamic analysis in the design stage and subsequent further analysis of the rotor only dynamics failed to predict the vibration characteristics found during testing. An advanced procedure for dynamics analysis was used in this investigation. The procedure involves developing accurate dynamic models of the rotor assembly and casing assembly by finite element analysis. The dynamically instrumented assemblies are independently rap tested to verify the analytical models. The verified models are then combined by modal superposition techniques to develop a completed turbopump model where dynamic characteristics are determined. The results of the dynamic testing and analysis obtained are presented and methods of moving the high speed vibration characteristics to speeds above the operating range are recommended. Recommendations for use of these advanced dynamic analysis procedures during initial design phases are given.

  5. Harnessing multicore processors for high-speed secure transfer.

    SciTech Connect

    Bresnahan, J.; Kettimuthu, R.; Link, M.; Foster, I.; Mathematics and Computer Science; Univ. of Chicago

    2007-01-01

    A growing need for ultra-high-speed data transfers has motivated continued improvements in the transmission speeds of the physical network layer. As researchers develop protocols and software to operate over such networks, they often fail to account for security. The processing power required to encrypt or sign packets of data can significantly decrease transfer rates, and thus security is often sacrificed for throughput. Emerging multicore processors provide a higher ratio of CPUs to network interfaces and can, in principle, be used to accelerate encrypted transfers by applying multiple processing and network resources to a single transfer. We discuss the attributes that network protocols and software must have to exploit such systems. In particular, we study how these attributes may be applied in the GridFTP code distributed with the globus toolkit. GridFTP is a well-accepted and robust protocol for high-speed data transfer. It has been shown to scale to near-network speeds. While GridFTP can provide encrypted and protected data transfers, it historically suffers transfer performance penalties when these features are enabled. We present configurations to the Globus GridFTP server that can achieve fully encrypted high-speed data transfers.

  6. Secondary Containment Design for a High Speed Centrifuge

    SciTech Connect

    Snyder, K.W.

    1999-03-01

    Secondary containment for high speed rotating machinery, such as a centrifuge, is extremely important for operating personnel safety. Containment techniques can be very costly, ungainly and time consuming to construct. A novel containment concept is introduced which is fabricated out of modular sections of polycarbonate glazed into a Unistrut metal frame. A containment study for a high speed centrifuge is performed which includes the development of parameters for secondary containment design. The Unistrut/polycarbonate shield framing concept is presented including design details and proof testing procedures. The economical fabrication and modularity of the design indicates a usefulness for this shielding system in a wide variety of containment scenarios.

  7. Multiply-agile encryption in high speed communication networks

    SciTech Connect

    Pierson, L.G.; Witzke, E.L.

    1997-05-01

    Different applications have different security requirements for data privacy, data integrity, and authentication. Encryption is one technique that addresses these requirements. Encryption hardware, designed for use in high-speed communications networks, can satisfy a wide variety of security requirements if that hardware is key-agile, robustness-agile and algorithm-agile. Hence, multiply-agile encryption provides enhanced solutions to the secrecy, interoperability and quality of service issues in high-speed networks. This paper defines these three types of agile encryption. Next, implementation issues are discussed. While single-algorithm, key-agile encryptors exist, robustness-agile and algorithm-agile encryptors are still research topics.

  8. High-speed multiplexing of keyboard data inputs

    NASA Technical Reports Server (NTRS)

    Anderson, T. O. (Inventor)

    1981-01-01

    A high speed multiplexing system is described in which keyboard entered data is sequentially and automatically sampled by the multiplexing system for input to a computer. A sequencer is provided which sequentially and automatically controls the multiplexer to sample each keyboard input in accordance with a predetermined sampling sequence. Whenever keyboard entered data appears on input lines to the multiplexer, the system inputs the keyboard data to the computer during a brief time interval in which the multiplexer remains at the particular keyboard address or port. Thus, a high speed sampling circuit is provided whereby the only operator action required is data entry through a keyboard. Priority or interrupt systems are not required.

  9. Summary of advanced methods for predicting high speed propeller performance

    NASA Technical Reports Server (NTRS)

    Bober, L. A.

    1980-01-01

    Three advanced analyses for predicting aircraft propeller performance at high subsonic speeds are described. Two of these analyses use a lifting line representation for the propeller blades and vortex filaments for the blade wakes but differ in the details of the solution. The third analysis is a finite difference solution of the unsteady, three dimensional Euler equations for the flow between adjacent blades. Analysis results are compared to data for a high speed propeller having eight swept blades integrally designed with the spinner and nacelle.

  10. Miniature high speed compressor having embedded permanent magnet motor

    NASA Technical Reports Server (NTRS)

    Zhou, Lei (Inventor); Zheng, Liping (Inventor); Chow, Louis (Inventor); Kapat, Jayanta S. (Inventor); Wu, Thomas X. (Inventor); Kota, Krishna M. (Inventor); Li, Xiaoyi (Inventor); Acharya, Dipjyoti (Inventor)

    2011-01-01

    A high speed centrifugal compressor for compressing fluids includes a permanent magnet synchronous motor (PMSM) having a hollow shaft, the being supported on its ends by ball bearing supports. A permanent magnet core is embedded inside the shaft. A stator with a winding is located radially outward of the shaft. The PMSM includes a rotor including at least one impeller secured to the shaft or integrated with the shaft as a single piece. The rotor is a high rigidity rotor providing a bending mode speed of at least 100,000 RPM which advantageously permits implementation of relatively low-cost ball bearing supports.

  11. High speed propeller acoustics and aerodynamics - A boundary element approach

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Myers, M. K.; Dunn, M. H.

    1989-01-01

    The Boundary Element Method (BEM) is applied in this paper to the problems of acoustics and aerodynamics of high speed propellers. The underlying theory is described based on the linearized Ffowcs Williams-Hawkings equation. The surface pressure on the blade is assumed unknown in the aerodynamic problem. It is obtained by solving a singular integral equation. The acoustic problem is then solved by moving the field point inside the fluid medium and evaluating some surface and line integrals. Thus the BEM provides a powerful technique in calculation of high speed propeller aerodynamics and acoustics.

  12. Introduction of the M-85 high-speed rotorcraft concept

    NASA Technical Reports Server (NTRS)

    Stroub, Robert H.

    1991-01-01

    As a result of studying possible requirements for high-speed rotorcraft and studying many high-speed concepts, a new high-speed rotorcraft concept, designated as M-85, was derived. The M-85 is a helicopter that is reconfigured to a fixed-wing aircraft for high-speed cruise. The concept was derived as an approach to enable smooth, stable conversion between fixed-wing and rotary-wing while retaining hover and low-speed flight characteristics of a low disk loading helicopter. The name, M-85, reflects the high-speed goals of 0.85 Mach number at high altitude. For a high-speed rotorcraft, it is expected that a viable concept must be a cruise-efficient, fixed-wing aircraft so it may be attractive for a multiplicity of missions. It is also expected that a viable high-speed rotorcraft concept must be cruise efficient first and secondly, efficient in hover. What makes the M-85 unique is the large circular hub fairing that is large enough to support the aircraft during conversion between rotary-wind and fixed-wing modes. With the aircraft supported by this hub fairing, the rotor blades can be unloaded during the 100 percent change in rotor rpm. With the blades unloaded, the potential for vibratory loads would be lessened. In cruise, the large circular hub fairing would be part of the lifting system with additional lifting panels deployed for better cruise efficiency. In hover, the circular hub fairing would slightly reduce lift potential and/or decrease hover efficiency of the rotor system. The M-85 concept is described and estimated forward flight performance characteristics are presented in terms of thrust requirements and L/D with airspeed. The forward flight performance characteristics reflect recent completed wind tunnel tests of the wing concept. Also presented is a control system technique that is critical to achieving low oscillatory loads in rotary-wing mode. Hover characteristics, C(sub p) versus C(sub T) from test data, is discussed. Other techniques pertinent to

  13. First Annual High-Speed Research Workshop, part 1

    NASA Technical Reports Server (NTRS)

    Whitehead, Allen H., Jr. (Compiler)

    1992-01-01

    The workshop was presented to provide a national forum for the government, industry, and university participants in the program to present and discuss important technology issues related to the development of a commercially viable, environmentally compatible U.S. High Speed Civil Transport. The workshop sessions were organized around the major task elements in NASA's Phase 1 High Speed Research Program which basically addressed the environmental issues of atmospheric emissions, community noise, and sonic boom. This volume is divided into three sessions entitled: Plenary Session (which gives overviews from NASA, Boeing, Douglas, GE, and Pratt & Whitney on the HSCT program); Airframe Systems Studies; and Atmospheric Effects.

  14. High speed propeller acoustics and aerodynamics - A boundary element approach

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Myers, M. K.; Dunn, M. H.

    1989-01-01

    The Boundary Element Method (BEM) is applied in this paper to the problems of acoustics and aerodynamics of high speed propellers. The underlying theory is described based on the linearized Ffowcs Williams-Hawkings equation. The surface pressure on the blade is assumed unknown in the aerodynamic problem. It is obtained by solving a singular integral equation. The acoustic problem is then solved by moving the field point inside the fluid medium and evaluating some surface and line integrals. Thus the BEM provides a powerful technique in calculation of high speed propeller aerodynamics and acoustics.

  15. Review of high-speed fiber optic grating sensor systems

    NASA Astrophysics Data System (ADS)

    Udd, Eric; Benterou, Jerry; May, Chadd; Mihailov, Stephen J.; Lu, Ping

    2010-04-01

    Fiber grating sensors can be used to support a wide variety of high speed measurement applications. This includes measurements of vibrations on bridges, traffic monitoring on freeways, ultrasonic detection to support non-destructive tests on metal plates, and providing details of detonation events. This paper provides a brief overview of some of the techniques that have been used to support high speed measurements using fiber grating sensors over frequency ranges from 10s of kHz, to MHZ and finally toward frequencies approaching the GHz regime.

  16. Proceedings: High-speed rail and maglev workshop

    SciTech Connect

    Not Available

    1993-04-01

    On October 30 and 31, 1991, the EPRI Public and Advanced Transportation Program sponsored a workshop on high-speed rail (HSR) and maglev. The purpose of this workshop was to provide utility managers with increased knowledge about these technologies, public policy regarding them, and their potential costs and benefits to utilities, including induced economic development. With this information, utilities should be better prepared to make decisions related to the development of these high speed intercity passenger options in their service areas. A main goal, achieved by the workshop, was to provide EPRI and its member utilities with ideas and information for developing an assessment and research agenda on these technologies.

  17. Development of magnetically levitated high speed transport system in Japan

    SciTech Connect

    Sawada, Kazuo

    1996-07-01

    In Japan, huge passenger traffic moves through the Tokyo-Osaka corridor and the demand is mounting on one more high speed line besides the Tokaido Shinkansen. A magnetically levitated vehicle (JR Maglev) using superconducting magnets has been developed for the Tokyo-Osaka superspeed express. JR Maglev has many advantages over conventional rail systems. This paper describes the necessity of one more high speed line in this corridor, the reason the author chose Maglev, the scheme of this system, history of the development and outline of the new Yamanashi test line project.

  18. Magneto-optical system for high speed real time imaging

    NASA Astrophysics Data System (ADS)

    Baziljevich, M.; Barness, D.; Sinvani, M.; Perel, E.; Shaulov, A.; Yeshurun, Y.

    2012-08-01

    A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

  19. Magneto-optical system for high speed real time imaging.

    PubMed

    Baziljevich, M; Barness, D; Sinvani, M; Perel, E; Shaulov, A; Yeshurun, Y

    2012-08-01

    A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

  20. A superconducting high-speed flywheel energy storage system

    NASA Astrophysics Data System (ADS)

    de Andrade, R.; Ferreira, A. C.; Sotelo, G. G.; Suemitsu, W. I.; Rolim, L. G. B.; Silva Neto, J. L.; Neves, M. A.; dos Santos, V. A.; da Costa, G. C.; Rosario, M.; Stephan, R.; Nicolsky, R.

    2004-08-01

    High-speed flywheel systems have been studied as compensators of voltage sags and momentary interruptions of energy. Besides the complexity of these systems, the main concerns are bearing losses. This work is part of the development of a superconducting high-speed flywheel energy storage prototype. In order to minimize the bearing losses, this system uses a superconducting axial thrust magnetic bearing in a vacuum chamber, which guarantees low friction losses, and a switched reluctance motor-generator to drive the flywheel system. Dynamic simulations made for this prototype, connected to the electric power network, show the viability of use it as a compensator.

  1. Multiplexed broadband beam steering system utilizing high speed MEMS mirrors.

    PubMed

    Knoernschild, Caleb; Kim, Changsoon; Lu, Felix P; Kim, Jungsang

    2009-04-27

    We present a beam steering system based on micro-electromechanical systems technology that features high speed steering of multiple laser beams over a broad wavelength range. By utilizing high speed micromirrors with a broadband metallic coating, our system has the flexibility to simultaneously incorporate a wide range of wavelengths and multiple beams. We demonstrate reconfiguration of two independent beams at different wavelengths (780 and 635 nm) across a common 5x5 array with 4 micros settling time. Full simulation of the optical system provides insights on the scalability of the system. Such a system can provide a versatile tool for applications where fast laser multiplexing is necessary.

  2. Ethylene Trace-gas Techniques for High-speed Flows

    NASA Technical Reports Server (NTRS)

    Davis, David O.; Reichert, Bruce A.

    1994-01-01

    Three applications of the ethylene trace-gas technique to high-speed flows are described: flow-field tracking, air-to-air mixing, and bleed mass-flow measurement. The technique involves injecting a non-reacting gas (ethylene) into the flow field and measuring the concentration distribution in a downstream plane. From the distributions, information about flow development, mixing, and mass-flow rates can be dtermined. The trace-gas apparatus and special considerations for use in high-speed flow are discussed. A description of each application, including uncertainty estimates is followed by a demonstrative example.

  3. Ultra-high-speed optical and electronic distributed devices

    SciTech Connect

    Hietala, V.M.; Plut, T.A.; Kravitz, S.H.; Vawter, G.A.; Wendt, J.R.; Armendariz, M.G.

    1995-08-01

    This report summarizes work on the development of ultra-high-speed semiconductor optical and electronic devices. High-speed operation is achieved by velocity matching the input stimulus to the output signal along the device`s length. Electronic devices such as field-effect transistors (FET`s), should experience significant speed increases by velocity matching the electrical input and output signals along the device. Likewise, optical devices, which are typically large, can obtain significant bandwidths by velocity matching the light being generated, detected or modulated with the electrical signal on the device`s electrodes. The devices discussed in this report utilize truly distributed electrical design based on slow-wave propagation to achieve velocity matching.

  4. Current situation: US tests under way. [High Speed Rail Transportation

    SciTech Connect

    Not Available

    1993-04-16

    Though US high-speed rail (HSR) activity is picking up, the technology is much farther advanced in Europe and Japan. Several HSR projects have been proposed for various parts of the country, but nearly all remain in the early developmental stages. The closest equivalent to regular high-speed rail service in the US still is provided by the Amtrak Metroliners running between New York and Washington. In late January, Amtrak began a three-month trial of a Swedish-built X2000 train on the New York-Washington run. Popularly known as the [open quotes]tilt train,[close quotes] it has a computer-guided suspension system that permits higher speeds on curves. The system enables trains to bank on curves, much as racing cars do, thus minimizing the queasiness that centrifugal force can cause. Passengers report feeling little or no discomfort when the X2000 tilts.

  5. High-speed wavefront modulation in complex media (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Turtaev, Sergey; Leite, Ivo T.; Cizmár, TomáÅ.¡

    2017-02-01

    Using spatial light modulators(SLM) to control light propagation through scattering media is a critical topic for various applications in biomedical imaging, optical micromanipulation, and fibre endoscopy. Having limited switching rate, typically 10-100Hz, current liquid-crystal SLM can no longer meet the growing demands of high-speed imaging. A new way based on binary-amplitude holography implemented on digital micromirror devices(DMD) has been introduced recently, allowing to reach refreshing rates of 30kHz. Here, we summarise the advantages and limitations in speed, efficiency, scattering noise, and pixel cross-talk for each device in ballistic and diffusive regimes, paving the way for high-speed imaging through multimode fibres.

  6. Research and design of high speed mass image storage system

    NASA Astrophysics Data System (ADS)

    Li, Yu-feng; Xue, Rong-kun; Liang, Fei

    2009-07-01

    The design of the high mass image storage system is introduced using DSP, FPGA and Flash structure. Texas Instruments Corporation DSP chip (TMS320VC5509APEG) is used as the main controller, Samsung's Flash chips (K9F2G08U0M) used as the main storage medium, and the Xilinx Corporation FPGA chip (XCV600E) used as logic control modules. In this system, Storage module consists of 32 Flash memory chips, which are divided into 8 groups that correspond to 8-level pipeline. The 4-Flash memory chip forms a basic 32-bit memory module. The entire system storage space is 64 G bit. Through simulation and verification, the storage speed is up to 352Mbps and readout speed is up to 290Mbps, it can meet the demand to the high-speed access, and which has strong environmental adaptability.

  7. Astronomical phenomena: events with high impact factor in teaching optics and photonics

    NASA Astrophysics Data System (ADS)

    Curticapean, Dan

    2014-07-01

    Astronomical phenomena fascinate people from the very beginning of mankind up to today. They have a enthusiastic effect, especially on young people. Among the most amazing and well-known phenomena are the sun and moon eclipses. The impact factor of such events is very high, as they are being covered by mass media reports and the Internet, which provides encyclopedic content and discussion in social networks. The principal optics and photonics topics that can be included in such lessons originate from geometrical optics and the basic phenomena of reflection, refraction and total internal reflection. Lenses and lens systems up to astronomical instruments also have a good opportunity to be presented. The scientific content can be focused on geometrical optics but also diffractive and quantum optics can be incorporated successfully. The author will present how live streams of the moon eclipses can be used to captivate the interest of young listeners for optics and photonics. The gathered experience of the last two moon eclipses visible from Germany (on Dec, 21 2010 and Jun, 15 2011) will be considered. In an interactive broadcast we reached visitors from more than 135 countries.

  8. Safety of high speed ground transportation systems: Safety of advanced braking concepts for high speed ground transportation systems. Final report

    SciTech Connect

    Wagner, D.P.; Ahlbeck, D.R.; Luedeke, J.F.; Cook, S.D.; Dielman, M.A.

    1995-09-01

    The objective of this study is to develop qualitative and quantitative information on the various braking strategies used in high-speed ground transportation systems in support of the Federal Railroad Administration (FRA). The approach employed in this study is composed of two steps: first, build a technical understanding of the various braking strategies, and second, perform a safety analysis for each system. The systems considered in this study include seven operating high-speed rail transportation systems and three existing magnetic levitation systems. The principal technique used in the system safety analysis is Failure Modes and Effects Analysis (FMEA), an inductive approach to identifying system failure modes that depends on a thorough understanding of the system design and operation. Key elements derived from the system safety analysis are the fault-tolerant and fail-safe characteristics of the braking systems. The report concludes with recommended guidance on the structure of potential future regulations governing high-speed rail braking systems.

  9. High-speed pulse-shape generator, pulse multiplexer

    DOEpatents

    Burkhart, Scott C.

    2002-01-01

    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  10. High-speed traveling-wave electro-absorption modulators

    NASA Astrophysics Data System (ADS)

    Westergren, Urban; Yu, Yichuan; Thylén, Lars

    2006-07-01

    Electroabsorption modulators (EAM) based on quantum-confined Stark effect (QCSE) in multiplequantum wells (MQW) have been demonstrated to provide high-speed, low drive voltage, and high extinction ratio. They are compact in size and can be monolithically integrated with continuous-wave (CW) lasers. In order to achieve both high speed and low drive-voltage operation, travelling-wave (TW) electrode structures can be used for EAMs. The inherently low impedance of high-speed EAMs may be transformed to values close to the standard 50Ohm impedance using periodic microwave structures with a combination of passive transmission lines with high characteristic impedance and active modulator sections with low impedance. Modulation bandwidths of 100GHz (-3dBe) have been accomplished with electrical reflections lower than -10dB in a 50Ohm system. Transmission at 80Gbit/s with non-return-to-zero (NRZ) code has been demonstrated for InP-based TWEAMs using electronic time-domain multiplexing (ETDM), indicating the possibility of reaching speeds of 100Gbit/s and beyond.

  11. High speed magneto-resistive random access memory

    NASA Technical Reports Server (NTRS)

    Wu, Jiin-Chuan (Inventor); Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor)

    1992-01-01

    A high speed read MRAM memory element is configured from a sandwich of magnetizable, ferromagnetic film surrounding a magneto-resistive film which may be ferromagnetic or not. One outer ferromagnetic film has a higher coercive force than the other and therefore remains magnetized in one sense while the other may be switched in sense by a switching magnetic field. The magneto-resistive film is therefore sensitive to the amplitude of the resultant field between the outer ferromagnetic films and may be constructed of a high resistivity, high magneto-resistive material capable of higher sensing currents. This permits higher read voltages and therefore faster read operations. Alternate embodiments with perpendicular anisotropy, and in-plane anisotropy are shown, including an embodiment which uses high permeability guides to direct the closing flux path through the magneto-resistive material. High density, high speed, radiation hard, memory matrices may be constructed from these memory elements.

  12. High-speed imaging of explosive eruptions: applications and perspectives

    NASA Astrophysics Data System (ADS)

    Taddeucci, Jacopo; Scarlato, Piergiorgio; Gaudin, Damien; Capponi, Antonio; Alatorre-Ibarguengoitia, Miguel-Angel; Moroni, Monica

    2013-04-01

    Explosive eruptions, being by definition highly dynamic over short time scales, necessarily call for observational systems capable of relatively high sampling rates. "Traditional" tools, like as seismic and acoustic networks, have recently been joined by Doppler radar and electric sensors. Recent developments in high-speed camera systems now allow direct visual information of eruptions to be obtained with a spatial and temporal resolution suitable for the analysis of several key eruption processes. Here we summarize the methods employed to gather and process high-speed videos of explosive eruptions, and provide an overview of the several applications of these new type of data in understanding different aspects of explosive volcanism. Our most recent set up for high-speed imaging of explosive eruptions (FAMoUS - FAst, MUltiparametric Set-up,) includes: 1) a monochrome high speed camera, capable of 500 frames per second (fps) at high-definition (1280x1024 pixel) resolution and up to 200000 fps at reduced resolution; 2) a thermal camera capable of 50-200 fps at 480-120x640 pixel resolution; and 3) two acoustic to infrasonic sensors. All instruments are time-synchronized via a data logging system, a hand- or software-operated trigger, and via GPS, allowing signals from other instruments or networks to be directly recorded by the same logging unit or to be readily synchronized for comparison. FAMoUS weights less than 20 kg, easily fits into four, hand-luggage-sized backpacks, and can be deployed in less than 20' (and removed in less than 2', if needed). So far, explosive eruptions have been recorded in high-speed at several active volcanoes, including Fuego and Santiaguito (Guatemala), Stromboli (Italy), Yasur (Vanuatu), and Eyjafiallajokull (Iceland). Image processing and analysis from these eruptions helped illuminate several eruptive processes, including: 1) Pyroclasts ejection. High-speed videos reveal multiple, discrete ejection pulses within a single Strombolian

  13. Strain rate effect in high-speed wire drawing process

    NASA Astrophysics Data System (ADS)

    He, S.; Van Houtte, P.; Van Bael, A.; Mei, F.; Sarban, A.; Boesman, P.; Galvez, F.; Atienza, J. M.

    2002-05-01

    This paper presents a study on the strain rate effect during high-speed wire drawing process by means of finite element simulation. Based on the quasistatic stresses obtained by normal tensile tests and dynamic stresses at high strain rates by split Hopkinson pressure bar tests, the wire drawing process was simulated for low carbon steel and high carbon steel. The results show that both the deformation process and the final properties of drawn wires are influenced by the strain rate.

  14. High-speed mass-transport phenomena during carburization of aluminum alloy by laser plasma treatment

    NASA Astrophysics Data System (ADS)

    Fariaut, F.; Boulmer-Leborgne, C.; Semmar, N.; Le Menn, E.

    2006-04-01

    In the excimer laser carburizing process reported here, aluminum alloy samples have been treated in a propylene atmosphere, producing aluminum carbide surface layers. The layers have been characterized by nuclear reaction analysis that has shown carbon incorporation. X-ray diffraction at grazing incidence has evidenced aluminum carbide (Al4C3) phase. This study helps the understanding of the incorporation mechanisms of carbon in a surface. A micro-thermocapillary effect induced by heterogeneous surface formation has been evidenced. This original mass-transport phenomenon is very efficient in improving the carbon incorporation yield and hence in obtaining carbide layers several μm in thickness with a reduced laser pulse number. In order to obtain this micro-thermocapillary effect, the binary diagram of ceramic compounds must contain a peritectic.

  15. High-Speed Cinematic Studies of Water Vaporization Phenomena in Electrothermal Hydrazine Thruster Simulations.

    DTIC Science & Technology

    1980-11-01

    EHT. The results of the flow visualiza- tion research are described, and it is concluded that Leidenfrost film-boiling effects inhibited vaporization...possibility of vaporization-rate dependence 5 2.2 The Leidenfrost phenomenon and the need for experimental study 6 2.3 The choice of water as a...boiling, and a study of some of the literature concerning the Leidenfrost phenomenon 14 ,15 suggested the possibility that propellent vaporization, and

  16. Characterization of Detonation Phenomena Observed in High-Speed Visible Imagery

    DTIC Science & Technology

    2006-03-01

    Ralph A. Anthenien Jr. (Member) date ____________________________________ ________ David W. Gerts, (Member) date...also like to express my gratitude to my committee members, Dr. Ronald Tuttle, Dr. Ralph Anthenien, and Major David Gerts for their selfless...DEMI) 4180 Watson Way Wright Patterson AFB, OH 45433 Sharon Staley , NASIC/DEMI DSN: 787-2962 11. SPONSOR/MONITOR’S REPORT NUMBER(S

  17. Background-Oriented Schlieren for Large-Scale and High-Speed Aerodynamic Phenomena

    NASA Technical Reports Server (NTRS)

    Mizukaki, Toshiharu; Borg, Stephen; Danehy, Paul M.; Murman, Scott M.; Matsumura, Tomoharu; Wakabayashi, Kunihiko; Nakayama, Yoshio

    2015-01-01

    Visualization of the flow field around a generic re-entry capsule in subsonic flow and shock wave visualization with cylindrical explosives have been conducted to demonstrate sensitivity and applicability of background-oriented schlieren (BOS) for field experiments. The wind tunnel experiment suggests that BOS with a fine-pixel imaging device has a density change detection sensitivity on the order of 10(sup -5) in subsonic flow. In a laboratory setup, the structure of the shock waves generated by explosives have been successfully reconstructed by a computed tomography method combined with BOS.

  18. Per-Pixel Coded Exposure for High-Speed and High-Resolution Imaging Using a Digital Micromirror Device Camera.

    PubMed

    Feng, Wei; Zhang, Fumin; Qu, Xinghua; Zheng, Shiwei

    2016-03-04

    High-speed photography is an important tool for studying rapid physical phenomena. However, low-frame-rate CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) camera cannot effectively capture the rapid phenomena with high-speed and high-resolution. In this paper, we incorporate the hardware restrictions of existing image sensors, design the sampling functions, and implement a hardware prototype with a digital micromirror device (DMD) camera in which spatial and temporal information can be flexibly modulated. Combined with the optical model of DMD camera, we theoretically analyze the per-pixel coded exposure and propose a three-element median quicksort method to increase the temporal resolution of the imaging system. Theoretically, this approach can rapidly increase the temporal resolution several, or even hundreds, of times without increasing bandwidth requirements of the camera. We demonstrate the effectiveness of our method via extensive examples and achieve 100 fps (frames per second) gain in temporal resolution by using a 25 fps camera.

  19. Per-Pixel Coded Exposure for High-Speed and High-Resolution Imaging Using a Digital Micromirror Device Camera

    PubMed Central

    Feng, Wei; Zhang, Fumin; Qu, Xinghua; Zheng, Shiwei

    2016-01-01

    High-speed photography is an important tool for studying rapid physical phenomena. However, low-frame-rate CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) camera cannot effectively capture the rapid phenomena with high-speed and high-resolution. In this paper, we incorporate the hardware restrictions of existing image sensors, design the sampling functions, and implement a hardware prototype with a digital micromirror device (DMD) camera in which spatial and temporal information can be flexibly modulated. Combined with the optical model of DMD camera, we theoretically analyze the per-pixel coded exposure and propose a three-element median quicksort method to increase the temporal resolution of the imaging system. Theoretically, this approach can rapidly increase the temporal resolution several, or even hundreds, of times without increasing bandwidth requirements of the camera. We demonstrate the effectiveness of our method via extensive examples and achieve 100 fps (frames per second) gain in temporal resolution by using a 25 fps camera. PMID:26959023

  20. High-speed civil transport study: Special factors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Studies relating to environmental factors associated with high speed civil transports were conducted. Projected total engine emissions for year 2015 fleets of several subsonic/supersonic transport fleet scenarios, discussion of sonic boom reduction methods, discussion of community noise level requirements, fuels considerations, and air traffic control impact are presented.