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Sample records for high speed switching

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Ultra High-Speed Radio Frequency Switch Based on Photonics

    PubMed Central

    Ge, Jia; Fok, Mable P.

    2015-01-01

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches. PMID:26608349

  7. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    PubMed

    Ge, Jia; Fok, Mable P

    2015-11-26

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  8. 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.

  9. 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.

  10. 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.

  11. High-Speed Computer-Controlled Switch-Matrix System

    NASA Technical Reports Server (NTRS)

    Spisz, E.; Cory, B.; Ho, P.; Hoffman, M.

    1985-01-01

    High-speed computer-controlled switch-matrix system developed for communication satellites. Satellite system controlled by onboard computer and all message-routing functions between uplink and downlink beams handled by newly developed switch-matrix system. Message requires only 2-microsecond interconnect period, repeated every millisecond.

  12. High-Speed Computer-Controlled Switch-Matrix System

    NASA Technical Reports Server (NTRS)

    Spisz, E.; Cory, B.; Ho, P.; Hoffman, M.

    1985-01-01

    High-speed computer-controlled switch-matrix system developed for communication satellites. Satellite system controlled by onboard computer and all message-routing functions between uplink and downlink beams handled by newly developed switch-matrix system. Message requires only 2-microsecond interconnect period, repeated every millisecond.

  13. MPLS switch architecture supporting Diffserv for high-speed switching and QoS

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Won; Kim, Young-Chul; Lee, Mike M.

    2004-03-01

    In this paper, we propose the architecture of the MPLS switch supporting Differentiated Services in the MPLS-based network. The traffic conditioner consists of a classifier, a meter, and a marker. The VOQ-PHB module which combines input queue with each PHB queue is implemented to utilize the resources more efficiently, employing the Priority-iSLIP scheduling algorithm to support high-speed switching. The proposed MPLS switch architecture is modeled and synthesized by Very High Speed Integrated Circuits Hardware Description Language (VHDL), verified and then implemented by commercialized CAD tools to justify the validity of the proposed hardware architecture.

  14. Electrically Switched Holographic Film for High Speed Optical Beam Steering

    NASA Astrophysics Data System (ADS)

    Sutherland, R. L.; Natarajan, L. V.; Tondiglia, V. P.; Bunning, T. J.

    1997-03-01

    We have developed a novel composite material which forms electrically switchable gratings upon standard holographic recording. The gratings consist of periodic arrays of nanometer scale liquid crystal domains in a dense polymer host. NMR and SEM studies indicate a homeotropic alignment of the liquid crystal with an axial defect or symmetry axis along the long axis of prolate sheroid droplets. Samples exhibit good optical quality with high diffraction efficiency in a single Bragg mode. The diffraction efficiency can be modulated by an external electric field, and wide on/off dynamic range switching (>25 dB) is achieved. Simple models relate the dynamic range, switching voltage (<5 V/μm), and response time (25 μs) to the material morphology. Applications incorporating high speed beam steering will be discussed.

  15. 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.

  16. Wideband, high speed switch matrix development for SS-TDMA applications

    NASA Technical Reports Server (NTRS)

    Prather, W. H.; Cory, B. J.; Wade, R. F.; Taft, W. J.; Buzinski, R. E.

    1981-01-01

    The paper describes the design of an SS-TDMA microwave switch matrix being developed as part of the NASA 30/20 GHz Communications Satellite Program. A critical element in the systems development is the high-speed wideband switching capability necessary for 30/20 GHz SS-TDMA trunking service interconnections. A proof-of-concept model of a 20-by-20 microwave switch matrix with a 2.5 GHz bandwidth and 10-nanosecond switching speeds is being developed to realize this capability.

  17. High switching speed electrically tuned microwave magnetic resonance devices

    NASA Astrophysics Data System (ADS)

    Radio, G. T.; Vittoria, C.; Ferrari, J. M.

    1984-12-01

    The present invention relates to a high speed tunable microwave cavity. More specifically the present invention relates to a microwave cavity loaded with a ferrite which exhibits the magneto-electric effect and that has a voltage applied across the ferrite which determines the resonance frequency of the cavity. Microwave beam shifting was originally produced by mechanical systems, or by a system of manifolding to distribute microwave energy to individual waveguide elements, where each element contains a phase shifter followed by an antenna transmitter. In the manifolded system, beam shifting is accomplished by applying electric currents to the phase shifters. The mechanical method of beam shifting is slow and readily subject to wear and malfunction. The manifolded method of beam shifting requires a considerable amount of space to accomplish power distribution and each consecutive phase shifter must shift a greater amount to maintain proper beam proportion, since phase shift is not additive or reciprocal.

  18. Quantifying and optimizing single-molecule switching nanoscopy at high speeds.

    PubMed

    Lin, Yu; Long, Jane J; Huang, Fang; Duim, Whitney C; Kirschbaum, Stefanie; Zhang, Yongdeng; Schroeder, Lena K; Rebane, Aleksander A; Velasco, Mary Grace M; Virrueta, Alejandro; Moonan, Daniel W; Jiao, Junyi; Hernandez, Sandy Y; Zhang, Yongli; Bewersdorf, Joerg

    2015-01-01

    Single-molecule switching nanoscopy overcomes the diffraction limit of light by stochastically switching single fluorescent molecules on and off, and then localizing their positions individually. Recent advances in this technique have greatly accelerated the data acquisition speed and improved the temporal resolution of super-resolution imaging. However, it has not been quantified whether this speed increase comes at the cost of compromised image quality. The spatial and temporal resolution depends on many factors, among which laser intensity and camera speed are the two most critical parameters. Here we quantitatively compare the image quality achieved when imaging Alexa Fluor 647-immunolabeled microtubules over an extended range of laser intensities and camera speeds using three criteria - localization precision, density of localized molecules, and resolution of reconstructed images based on Fourier Ring Correlation. We found that, with optimized parameters, single-molecule switching nanoscopy at high speeds can achieve the same image quality as imaging at conventional speeds in a 5-25 times shorter time period. Furthermore, we measured the photoswitching kinetics of Alexa Fluor 647 from single-molecule experiments, and, based on this kinetic data, we developed algorithms to simulate single-molecule switching nanoscopy images. We used this software tool to demonstrate how laser intensity and camera speed affect the density of active fluorophores and influence the achievable resolution. Our study provides guidelines for choosing appropriate laser intensities for imaging Alexa Fluor 647 at different speeds and a quantification protocol for future evaluations of other probes and imaging parameters.

  19. Quantifying and Optimizing Single-Molecule Switching Nanoscopy at High Speeds

    PubMed Central

    Lin, Yu; Long, Jane J.; Huang, Fang; Duim, Whitney C.; Kirschbaum, Stefanie; Zhang, Yongdeng; Schroeder, Lena K.; Rebane, Aleksander A.; Velasco, Mary Grace M.; Virrueta, Alejandro; Moonan, Daniel W.; Jiao, Junyi; Hernandez, Sandy Y.; Zhang, Yongli; Bewersdorf, Joerg

    2015-01-01

    Single-molecule switching nanoscopy overcomes the diffraction limit of light by stochastically switching single fluorescent molecules on and off, and then localizing their positions individually. Recent advances in this technique have greatly accelerated the data acquisition speed and improved the temporal resolution of super-resolution imaging. However, it has not been quantified whether this speed increase comes at the cost of compromised image quality. The spatial and temporal resolution depends on many factors, among which laser intensity and camera speed are the two most critical parameters. Here we quantitatively compare the image quality achieved when imaging Alexa Fluor 647-immunolabeled microtubules over an extended range of laser intensities and camera speeds using three criteria – localization precision, density of localized molecules, and resolution of reconstructed images based on Fourier Ring Correlation. We found that, with optimized parameters, single-molecule switching nanoscopy at high speeds can achieve the same image quality as imaging at conventional speeds in a 5–25 times shorter time period. Furthermore, we measured the photoswitching kinetics of Alexa Fluor 647 from single-molecule experiments, and, based on this kinetic data, we developed algorithms to simulate single-molecule switching nanoscopy images. We used this software tool to demonstrate how laser intensity and camera speed affect the density of active fluorophores and influence the achievable resolution. Our study provides guidelines for choosing appropriate laser intensities for imaging Alexa Fluor 647 at different speeds and a quantification protocol for future evaluations of other probes and imaging parameters. PMID:26011109

  20. Research on 1x2 all fiber high-speed magneto-optic switch

    NASA Astrophysics Data System (ADS)

    Lin, Shaohan; Weng, Zihua; Wang, Minfeng; Chen, Xu; Ruan, Jianjian

    2008-11-01

    In this paper two new types of 1x2 all fiber high-speed magneto-optic switches with thick film ferromagnetic bismuth-substituted rare-earth iron garnets are proposed and tested. Two types of magneto-optic switches are discussed by using two kinds of crystals. One is the ordinary switch which needs indurance magnetic field to maintain its state; And the other is latching type switch, the crystal remains in a given magnetic state for unlimited duration without energy supply. Circuits used to generate magnetic field are also discussed. The theoretical and experimental analysis of optical route, measurement of switching time and magnetic filed etc. are included. The extinction ratio of the switches are currently about 20 dB. It can be improved further by additional Faraday rotation created by another magneto-optic (MO) material in the light path. The switching time of MO material is under 100 ns, it can be ignored. Magnetic field should be able to change the voltage rapidly in order to obtain fast operating time of the optical switch. The inductance of the solenoid used for generating the required magnetic field is the bottleneck for rapid switching of the magnetic field in the MO material. The switching time of the two optical switch are discussed.

  1. Simultaneous Switching Noise Analysis for High-Speed Interface

    NASA Astrophysics Data System (ADS)

    Takahashi, Narimasa; Kagawa, Kenji; Honda, Yutaka; Takahashi, Yo

    This paper describes the modeling and the analysis methodology to evaluate Simultaneous Switching Noise (SSN) for the combined system of the package with the 4-layer Printed Circuit Board (PCB), which the 64 Simultaneous Switching Outputs (SSOs) were included using a simple IBIS model. Simulation results showed that the ground plane in both package and PCB can be used as the reference to reduce SSN more effectively than the power plane. For the source synchronous timing technique such as used in a DDR SDRAM memory bus in the model shown in this paper, the skew control circuit tequiniqe is easy to apply in the chip design instead of using embedded capacitors in the package's substrate. And also the radiated emission and eye diagram analysis were studied.

  2. Fiber Fabry-Perot tunable filter for high-speed optical packet switching

    SciTech Connect

    Taranenko, N.L.; Tenbrink, S.C.; Hsu, K.; Miller, C.M.

    1997-01-01

    Tunable optical filters are important building blocks for All-Optical systems and networks. Fast optical tuning in several microseconds is necessary to perform high-speed optical packet switching. Multi- Gigabit/sec packet-switching will provide flexibility and higher network throughput when large numbers of users communicate simultaneously. One approach to achieve fast wavelength tuning is to use high-speed piezoelectrically-driven Fiber Fabry-Perot tunable filters (FFP-TFs). The requirement for tuning in microseconds raises a whole new set of challenges, such as ringing, thermostability and mechanical inertia control. It was shown that correlation between the mechanical resonance and optical response of the filter is important for the filter`s speed and for mounting hardware and control circuitry optimization. These features together with the FFP-TF`s high capacitance (approximately 0.25-0.5 microfarad) are being folded into building a special controller to substantially improve the shape of the driving signal and the response of the filter. The resultant controller enables tuning the high-speed FFP-TF three-orders-of- magnitude faster than that possible with standard commercial FFP-TFS. The fastest switching time achieved is 2.5 microseconds. As the result, a new packet-switched media access control protocol is being designed to minimize the searching time. The filter scans only once through the entire optical region and then tunes to all the required channels one after another in a few microseconds. It can help update Rainbow-2 Broadcast-and-Select High-Speed Wavelength Division Multiplexing All-Optical network that currently has a circuit- switched protocol using standard FFP-TFS.

  3. A high-performance angular speed measurement method based on adaptive hysteresis switching techniques

    NASA Astrophysics Data System (ADS)

    Huang, Haiming; Chou, Wusheng; Zhang, Zuojiang

    2015-12-01

    The high-performance measurement of angular speed (AS) is an essential requirement for achieving the high accuracy of machine control and monitoring. This paper proposes a new adaptive AS measurement system, which minimizes AS errors and fluctuations from conventional AS methods in a wide range of AS measurement. Unlike the conventional switches used previously, the system is composed of two layers of hysteresis switches, hereinafter referred to as the inner and outer hysteresis switch, respectively, to count pulses from an optical encoder adaptively. To highlight the key techniques used, the system is named as a hysteresis switch-based adaptation AS measurement (HS-AASM). The proposed method is designed and implemented based on a cost-effective TMS320F28335 digital signal controller (DSC). The performance analyses and experimental verifications show that the HS-AASM method outperforms the existing methods.

  4. The MAJIC-FET - A high speed power switch with low on-resistance

    NASA Astrophysics Data System (ADS)

    Baliga, B. J.

    1982-07-01

    A new device, called the MAJIC-FET, has been developed for high power switching applications that exhibits a low on-resistance during current conduction in order to minimize the steady-state conduction losses, and high speed turn-off to minimize the switching losses. The semiconductor device operates at high current densities during forward conduction, and the chip size can be minimized for any given current handling capacity. In this device, the injection of minority carriers from the gate junction controls its admittance.

  5. Motor models and transient analysis for high-temperature, superconductor switch-based adjustable speed drive applications. Final report

    SciTech Connect

    Bailey, J.M.

    1996-06-01

    New high-temperature superconductor (HTSC) technology may allow development of an energy-efficient power electronics switch for adjustable speed drive (ASD) applications involving variable-speed motors, superconducting magnetic energy storage systems, and other power conversion equipment. This project developed a motor simulation module for determining optimal applications of HTSC-based power switches in ASD systems.

  6. Study of Electromagnetic Repulsion Switch to High Speed Reclosing and Recover Time Characteristics of Superconductor

    NASA Astrophysics Data System (ADS)

    Koyama, Tomonori; Kaiho, Katsuyuki; Yamaguchi, Iwao; Yanabu, Satoru

    Using a high-temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor and vacuum interrupter as the commutation switch were connected in parallel using a bypass coil. When the fault current flows in this equipment, the superconductor is quenched and the current is then transferred to the parallel coil due to the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter and the current in the superconductor is broken. Using this equipment, the current flow time in the superconductor can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of the parallel coil. This system has many merits. So, we introduced to electromagnetic repulsion switch. There is duty of high speed re-closing after interrupting fault current in the electrical power system. So the SFCL should be recovered to superconducting state before high speed re-closing. But, superconductor generated heat at the time of quench. It takes time to recover superconducting state. Therefore it is a matter of recovery time. In this paper, we studied recovery time of superconductor. Also, we proposed electromagnetic repulsion switch with reclosing system.

  7. Attenuation of front-end reflections in an impulse radar using high-speed switching

    NASA Astrophysics Data System (ADS)

    Mazzaro, Gregory J.; Ressler, Marc A.; Smith, Gregory D.

    2011-06-01

    Pulse reflection between front-end components is a common problem for impulse radar systems. Such reflections arise because radio frequency components are rarely impedance-matched over an ultra-wide bandwidth. Any mismatch between components causes a portion of the impulse to reflect within the radar front-end. If the reflection couples into the transmit antenna, the radar emits an unintended, delayed and distorted replica of the intended radar transmission. These undesired transmissions reflect from the radar environment, produce echoes in the radar image, and generate false alarms in the vicinity of actual targets. The proposed solution for eliminating these echoes, without redesigning the transmit antenna, is to dissipate pulse reflections in a matched load before they are emitted. A high-speed switch directs the desired pulse to the antenna and redirects the undesired reflection from the antenna to a matched load. The Synchronous Impulse Reconstruction (SIRE) radar developed by the Army Research Laboratory (ARL) is the case-study. This paper reviews the current front-end design, provides a recent radar image which displays the aforementioned echoes, and describes the switch-cable-load circuit solution for eliminating the echoes. The consequences of inserting each portion of the new hardware into the radar front-end are explained. Measurements on the front-end with the high-speed switch show an attenuation of the undesired pulse transmissions of more than 18 dB and an attenuation in the desired pulse transmission of less than 3 dB.

  8. High speed Deans switch for low duty cycle comprehensive two-dimensional gas chromatography.

    PubMed

    Ghosh, Abhijit; Bates, Carly T; Seeley, Stacy K; Seeley, John V

    2013-05-24

    A new high-speed valve-based modulator has been designed and tested for use in comprehensive two-dimensional gas chromatography (GC×GC). The modulator is a Deans switch constructed from two micro-volume fittings and a solenoid valve. Modulator performance was characterized over a wide range of device settings including the magnitude of the switching flow, the gap between the tips of the primary and secondary column, the primary column flow rate, and the carrier gas identity. Under optimized conditions, the modulator was found to be capable of generating narrow pulses (<50ms) of primary effluent with a 2mL/min secondary column flow. This capability will ultimately allow the modulator to be used with GC×GC separations employing a wide range of detectors and secondary column geometries. The main disadvantage of this modulator is that it employs a low sampling duty cycle, and thus it produces separations with sensitivities that are lower than those produced with thermal modulators or differential flow modulators. The efficacy of the new high-speed Deans switch modulator was demonstrated through the GC×GC separation of a hydrocarbon standard and gasoline. Precise quantitation of individual components was possible provided the modulation ratio was kept greater than 2.0.

  9. Switching speed effect of phase shift keying in SLED for generating high power microwaves

    NASA Astrophysics Data System (ADS)

    Xiong, Zheng-Feng; Cheng, Cheng; Yu, Jian; Chen, Huai-Bi; Ning, Hui

    2016-01-01

    SLAC energy doubler (SLED) type radio-frequency pulse compressors are widely used in large-scale particle accelerators for converting long-duration moderate-power input pulses into short-duration high-power output pulses. Phase shift keying (PSK) is one of the key components in SLED pulse compression systems. Performance of the PSK will influence the output characteristics of the SLED, such as the rise-time of the output pulse, maximal peak power gain, and energy efficiency. In this paper, a high power microwave source based on power combining and pulse compression of conventional klystrons is introduced. The effects of nonideal PSK with slow switching speed and PSK without power output during the switching process are investigated, and the experimental results with nonideal PSK agree well with the analytical results.

  10. Integrated tests of a high speed VXS switch card and 250 MSPS flash ADCs

    SciTech Connect

    H. Dong, C. Cuevas, D. Curry, E. Jastrzembski, F. Barbosa, J. Wilson, M. Taylor, B. Raydo

    2008-01-01

    High trigger rate nuclear physics experiments proposed for the 12 GeV upgrade at the Thomas Jefferson National Accelerator Facility create a need for new high speed digital systems for energy summing. Signals from electronic detectors will be captured with the Jefferson Lab FADC module, which collects and processes data from 16 charged particle sensors with 10 or 12 bit resolution at 250 MHz sample rate. Up to sixteen FADC modules transfer energy information to a central energy summing module for each readout crate. The sums from the crates are combined to form a global energy sum that is used to trigger data readout for all modules. The Energy Sum module and FADC modules have been designed using the VITA-41 VME64 switched serial (VXS) standard. The VITA- 41 standard defines payload and switch slot module functions, and offers an elegant engineered solution for Multi-Gigabit serial transmission on a standard VITA-41 backplane. The Jefferson Lab Energy Sum module receives data serially at a rate of up to 6 Giga-bits per second from the FADC modules. Both FADC and Energy Sum modules have been designed and assembled and this paper describes the integrated tests using both high speed modules in unison

  11. CHEETAH: circuit-switched high-speed end-to-end transport architecture

    NASA Astrophysics Data System (ADS)

    Veeraraghavan, Malathi; Zheng, Xuan; Lee, Hyuk; Gardner, M.; Feng, Wuchun

    2003-10-01

    Leveraging the dominance of Ethernet in LANs and SONET/SDH in MANs and WANs, we propose a service called CHEETAH (Circuit-switched High-speed End-to-End Transport ArcHitecture). The service concept is to provide end hosts with high-speed, end-to-end circuit connectivity on a call-by-call shared basis, where a "circuit" consists of Ethernet segments at the ends that are mapped into Ethernet-over-SONET long-distance circuits. This paper focuses on the file-transfer application for such circuits. For this application, the CHEETAH service is proposed as an add-on to the primary Internet access service already in place for enterprise hosts. This allows an end host that is sending a file to first attempt setting up an end-to-end Ethernet/EoS circuit, and if rejected, fall back to the TCP/IP path. If the circuit setup is successful, the end host will enjoy a much shorter file-transfer delay than on the TCP/IP path. To determine the conditions under which an end host with access to the CHEETAH service should attempt circuit setup, we analyze mean file-transfer delays as a function of call blocking probability in the circuit-switched network, probability of packet loss in the IP network, round-trip times, link rates, and so on.

  12. Monolithic, High-Speed Fiber-Optic Switching Array for Lidar

    NASA Technical Reports Server (NTRS)

    Suckow, Will; Roberts, Tony; Switzer, Gregg; Terwilliger, Chelle

    2011-01-01

    Current fiber switch technologies use mechanical means to redirect light beams, resulting in slow switch time, as well as poor reliability due to moving parts wearing out quickly at high speeds. A non-mechanical ability to switch laser output into one of multiple fibers within a fiber array can provide significant power, weight, and costs savings to an all-fiber system. This invention uses an array of crystals that act as miniature prisms to redirect light as an electric voltage changes the prism s properties. At the heart of the electro-optic fiber-optic switch is an electro- optic crystal patterned with tiny prisms that can deflect the beam from the input fiber into any one of the receiving fibers arranged in a linear array when a voltage is applied across the crystal. Prism boundaries are defined by a net dipole moment in the crystal lattice that has been poled opposite to the surrounding lattice fabricated using patterned, removable microelectrodes. When a voltage is applied across the crystal, the resulting electric field changes the index of refraction within the prism boundaries relative to the surrounding substrate, causing light to deflect slightly according to Snell s Law. There are several materials that can host the necessary monolithic poled pattern (including, but not limited to, SLT, KTP, LiNbO3, and Mg:LiNbO3). Be cause this is a solid-state system without moving parts, it is very fast, and does not wear down easily. This invention is applicable to all fiber networks, as well as industries that use such networks. The unit comes in a compact package, can handle both low and high voltages, and has a high reliability (100,000 hours without maintenance).

  13. A low-voltage high-speed electronic switch based on piezoelectric transduction

    NASA Astrophysics Data System (ADS)

    Newns, Dennis; Elmegreen, Bruce; Hu Liu, Xiao; Martyna, Glenn

    2012-04-01

    We propose a novel digital switch, the piezoelectronic transistor or PET. Based on properties of known materials, we predict that a nanometer-scale PET can operate at low voltages and relatively high speeds, exceeding the capabilities of any conventional field effect transistor (FET). Depending on the degree to which these attributes can be simultaneously achieved, the device has a broad array of potential applications in digital logic. The PET is a 3-terminal switch in which a gate voltage is applied to a piezoelectric (PE), resulting in expansion compressing a piezoresistive (PR) material comprising the channel, which then undergoes a continuous, reversible insulator-metal transition. The channel becomes conducting in response to the gate voltage. A high piezoelectric coefficient PE, e.g., a relaxor piezoelectric, leads to low voltage operation. Suitable channel materials manifesting a pressure-induced metal-insulator transition can be found amongst rare earth chalcogenides, transition metal oxides, and among others. Mechanical requirements include a high PE/PR area ratio to step up pressure, a rigid surround material to constrain the PE and PR external boundaries normal to the strain axis, and a void space to enable free motion of the component side walls. Using static mechanical modeling and dynamic electro-acoustic simulations, we optimize device structure and materials and predict performance.

  14. High-speed pulsed mixing in a short distance with high-frequency switching of pumping from three inlets

    NASA Astrophysics Data System (ADS)

    Sugano, K.; Nakata, A.; Tsuchiya, T.; Tabata, O.

    2015-08-01

    In this study, we propose a mixing method using alternate pulsed flows from three inlets with flow direction control. In conventional pulsed mixing, a residual flow near the sidewalls inhibits the rapid mixing of two solutions at high switching frequency. In this study, we addressed this issue in order to perform rapid mixing in a short distance with a low Reynolds number. We fabricated a microfluidic mixing device consisting of a cross-shaped mixing channel with three inlet microchannels and three valveless micropumps. In conventional T-shaped or Y-shaped mixing channels, a residual flow is observed because of the incomplete switching of solutions. The three inlet configuration enabled us to split the residual flow at a switching frequency of pumping of up to 200 Hz, thus resulting in rapid mixing. Furthermore, by controlling the flow direction at the confluent area using the reverse flow of the micropump, the mixing speed was dramatically increased because of the complete switching of the two solutions. As a result, we achieved the mixing time of 3.6 ms and the mixing length of 20.7 µm, which were necessary to achieve a 90% mixing ratio at a high micropump switching frequency of 400 Hz and reverse flow ratio of 1/4.

  15. Analytical modeling of trilayer graphene nanoribbon Schottky-barrier FET for high-speed switching applications.

    PubMed

    Rahmani, Meisam; Ahmadi, Mohammad Taghi; Abadi, Hediyeh Karimi Feiz; Saeidmanesh, Mehdi; Akbari, Elnaz; Ismail, Razali

    2013-01-30

    Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistors. The current-voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current-voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption.

  16. Analytical modeling of trilayer graphene nanoribbon Schottky-barrier FET for high-speed switching applications

    PubMed Central

    2013-01-01

    Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistors. The current–voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current–voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption. PMID:23363692

  17. Investigation of DC hybrid circuit breaker based on high-speed switch and arc generator.

    PubMed

    Wu, Yifei; Rong, Mingzhe; Wu, Yi; Yang, Fei; Li, Mei; Zhong, Jianying; Han, Guohui; Niu, Chunping; Hu, Yang

    2015-02-01

    A new design of DC hybrid circuit breaker based on high-speed switch (HSS) and arc generator (AG), which can drastically profit from low heat loss in normal state and fast current breaking under fault state, is presented and analyzed in this paper. AG is designed according to the magnetic pinch effect of liquid metal. By utilizing the arc voltage generated across AG, the fault current is rapidly commutated from HSS into parallel connected branch. As a consequence, the arcless open of HSS is achieved. The post-arc conducting resume time (Δ tc) of AG and the commutation original voltage (Uc), two key factors in the commutation process, are investigated experimentally. Particularly, influences of the liquid metal channel diameter (Φ) of AG, fault current rate of rise (di/dt) and Uc on Δ tc are focused on. Furthermore, a suitable Uc is determined during the current commutation process, aiming at the reliable arcless open of HSS and short breaking time. Finally, the fault current breaking test is carried out for the current peak value of 11.8 kA, and the validity of the design is confirmed by the experimental results.

  18. Investigation of DC hybrid circuit breaker based on high-speed switch and arc generator

    NASA Astrophysics Data System (ADS)

    Wu, Yifei; Rong, Mingzhe; Wu, Yi; Yang, Fei; Li, Mei; Zhong, Jianying; Han, Guohui; Niu, Chunping; Hu, Yang

    2015-02-01

    A new design of DC hybrid circuit breaker based on high-speed switch (HSS) and arc generator (AG), which can drastically profit from low heat loss in normal state and fast current breaking under fault state, is presented and analyzed in this paper. AG is designed according to the magnetic pinch effect of liquid metal. By utilizing the arc voltage generated across AG, the fault current is rapidly commutated from HSS into parallel connected branch. As a consequence, the arcless open of HSS is achieved. The post-arc conducting resume time (Δ tc) of AG and the commutation original voltage (Uc), two key factors in the commutation process, are investigated experimentally. Particularly, influences of the liquid metal channel diameter (Φ) of AG, fault current rate of rise (di/dt) and Uc on Δ tc are focused on. Furthermore, a suitable Uc is determined during the current commutation process, aiming at the reliable arcless open of HSS and short breaking time. Finally, the fault current breaking test is carried out for the current peak value of 11.8 kA, and the validity of the design is confirmed by the experimental results.

  19. Analysis of Fault Arc in High-Speed Switch Applied in Hybrid Circuit Breaker

    NASA Astrophysics Data System (ADS)

    Wu, Yifei; Ren, Zhigang; Feng, Ying; Li, Mei; Zhang, Hantian

    2016-03-01

    The behavior of fault arc in a high-speed switch (HSS) has been studied theoretically and experimentally. A simplified HSS setup is designed to support this work. A two-dimensional arc model is developed to analyze the characteristics of fault arc based on magnetic-hydrodynamic (MHD) theory. The advantage of such a model is that the thermal transfer coefficient can be determined by depending on the numerical method alone. The influence of net emission coefficients (NEC) radiation model and P1 model on fault arc is analyzed in detail. Results show that NEC model predicts more radiation energy and less pressure rise without the re-absorption effect considered. As a consequence, P1 model is more suitable to calculate the pressure rise caused by fault arc. Finally, the pressure rise during longer arcing time for different arc currents is predicted. supported by National Key Basic Research Program of China (973 Program) (No. 2015CB251001), National Natural Science Foundation of China (Nos. 51221005, 51177124, 51377128, 51323012), the Science and Technology Project Funds of the Grid State Corporation SGSNKYOOKJJS1501564 and Shaanxi Province Natural Science Foundation of China (No. 2013JM-7010)

  20. High Speed Switches for Reconfigurable Optical Logic Arrays and Optical Interconnections

    DTIC Science & Technology

    2007-11-02

    VCSELs with heterojunction phototransistors (HPTs) and photothyristors produced several families of high performance optical switches with alternatively...components - such as heterojunction phototransistors (HPTs), photothyristors (PNPNs), or p-i-n photodiodes (PINs) - and with electronics, such as...heterojunction phototransistors (3T-HPTs) and a VCSEL, demonstrated optical switching and optoelectronic signal conversion at >200 Mb/s (0.8 ns rise time

  1. High-performance prediction for variable-speed switched reluctance drives

    SciTech Connect

    Ismail, F.; Wahsh, S.; Mohamed, A.Z.

    1997-12-31

    This work presents a simple developed nonlinear dynamic model of variable reluctance motor (VRM) based on its magnetic characteristics, considering the saturation effect. Most preliminary design work is centered on a fixed speed, or a small number of fixed speeds, even when the requirement is for operation over a wide speed range. This work deals with both constant and variable speed operation. Model development is motivated by the good performance predictions required to support and simplify the design of a high performance controller. Because the magnetization curves do not need to be pre-calculated, measured, stored, curve-fitted, or idealized the model is extremely simple, fast, and accurate. Simulation results of the phase current and torque on both chopping and single-pulse mode of operations are presented.

  2. A switched capacitor array based system for high-speed calorimetry

    SciTech Connect

    Levi, M.; Bebek, C.; Ely, R.; Jared, R.; Kipnis, I.; Kirsten, F.; Kleinfelder, S.; Merrick, T.; Milgrome, O.

    1991-12-01

    A sixteen channel analog transient recorder with 256 cells per channel has been fabricated as an integrated circuit. The circuit uses switched capacitor array technology to achieve simultaneous read/write capability and twelve bit dynamic range. Combined with highly parallel analog-to-digital converter and readout control circuitry being developed this system should satisfy the demanding electronics requirements for calorimeter detectors at the SSC. The system design and test results are presented.

  3. Displacement monitoring of switch track and its slab on a bridge of high speed railway by FBG

    NASA Astrophysics Data System (ADS)

    Li, Weilai; Li, He; Cheng, Jian; Huang, Xiaomei; Pan, Jianjun; Zhou, Ciming; Yang, Minghong

    2011-05-01

    In a 350km/h high speed railway line, there is a seamless switch with ballastless slabs built on a bridge. 54 Fiber Bragg Grating detecting cells are employed to monitor the displacement of track and slab. The cell is of extending function of measurement range, up to 50mm displacement, and is of good linearity. Protecting methods for cells and fiber are adopted to keep them surviving from the harsh conditions. The results show that in 75 days, the displacement of the track and sleeper slab was 8-9mm, and the displacement is of high correlation with daily environmental temperature change.

  4. Design and Implementation of High-Speed Input-Queued Switches Based on a Fair Scheduling Algorithm

    NASA Astrophysics Data System (ADS)

    Hu, Qingsheng; Zhao, Hua-An

    To increase both the capacity and the processing speed for input-queued (IQ) switches, we proposed a fair scalable scheduling architecture (FSSA). By employing FSSA comprised of several cascaded sub-schedulers, a large-scale high performance switches or routers can be realized without the capacity limitation of monolithic device. In this paper, we present a fair scheduling algorithm named FSSA_DI based on an improved FSSA where a distributed iteration scheme is employed, the scheduler performance can be improved and the processing time can be reduced as well. Simulation results show that FSSA_DI achieves better performance on average delay and throughput under heavy loads compared to other existing algorithms. Moreover, a practical 64 × 64 FSSA using FSSA_DI algorithm is implemented by four Xilinx Vertex-4 FPGAs. Measurement results show that the data rates of our solution can be up to 800Mbps and the tradeoff between performance and hardware complexity has been solved peacefully.

  5. A Study of Quality of Service Communication for High-Speed Packet-Switching Computer Sub-Networks

    NASA Technical Reports Server (NTRS)

    Cui, Zhenqian

    1999-01-01

    In this thesis, we analyze various factors that affect quality of service (QoS) communication in high-speed, packet-switching sub-networks. We hypothesize that sub-network-wide bandwidth reservation and guaranteed CPU processing power at endpoint systems for handling data traffic are indispensable to achieving hard end-to-end quality of service. Different bandwidth reservation strategies, traffic characterization schemes, and scheduling algorithms affect the network resources and CPU usage as well as the extent that QoS can be achieved. In order to analyze those factors, we design and implement a communication layer. Our experimental analysis supports our research hypothesis. The Resource ReSerVation Protocol (RSVP) is designed to realize resource reservation. Our analysis of RSVP shows that using RSVP solely is insufficient to provide hard end-to-end quality of service in a high-speed sub-network. Analysis of the IEEE 802.lp protocol also supports the research hypothesis.

  6. High speed imaging of dynamic processes with a switched source x-ray CT system

    NASA Astrophysics Data System (ADS)

    Thompson, William M.; Lionheart, William R. B.; Morton, Edward J.; Cunningham, Mike; Luggar, Russell D.

    2015-05-01

    Conventional x-ray computed tomography (CT) scanners are limited in their scanning speed by the mechanical constraints of their rotating gantries and as such do not provide the necessary temporal resolution for imaging of fast-moving dynamic processes, such as moving fluid flows. The Real Time Tomography (RTT) system is a family of fast cone beam CT scanners which instead use multiple fixed discrete sources and complete rings of detectors in an offset geometry. We demonstrate the potential of this system for use in the imaging of such high speed dynamic processes and give results using simulated and real experimental data. The unusual scanning geometry results in some challenges in image reconstruction, which are overcome using algebraic iterative reconstruction techniques and explicit regularisation. Through the use of a simple temporal regularisation term and by optimising the source firing pattern, we show that temporal resolution of the system may be increased at the expense of spatial resolution, which may be advantageous in some situations. Results are given showing temporal resolution of approximately 500 µs with simulated data and 3 ms with real experimental data.

  7. Ultra-High Speed Optical Communication and Switching via Novel Quantum Devices.

    DTIC Science & Technology

    1995-09-01

    A joint theoretical experimental research program was undertaken to initiate the development of novel quantum devices for greatly improved optical ... communication and switching in both local network and long haul applications. Specifically, Northwest University theoretically investigated and

  8. High-speed switching of biphoton delays through electro-optic pump frequency modulation

    DOE PAGES

    Odele, Ogaga D.; Lukens, Joseph M.; Jaramillo-Villegas, Jose A.; ...

    2016-12-08

    The realization of high-speed tunable delay control has received significant attention in the scene of classical photonics. In quantum optics, however, such rapid delay control systems for entangled photons have remained undeveloped. Here for the first time, we demonstrate rapid (2.5 MHz) modulation of signal-idler arrival times through electro-optic pump frequency modulation. Our technique applies the quantum phenomenon of nonlocal dispersion cancellation along with pump frequency tuning to control the relative delay between photon pairs. Chirped fiber Bragg gratings are employed to provide large amounts of dispersion which result in biphoton delays exceeding 30 ns. This rapid delay modulation schememore » could be useful for on-demand single-photon distribution in addition to quantum versions of pulse position modulation.« less

  9. High-speed switching of biphoton delays through electro-optic pump frequency modulation

    NASA Astrophysics Data System (ADS)

    Odele, Ogaga D.; Lukens, Joseph M.; Jaramillo-Villegas, Jose A.; Imany, Poolad; Langrock, Carsten; Fejer, Martin M.; Leaird, Daniel E.; Weiner, Andrew M.

    2017-01-01

    The realization of high-speed tunable delay control has received significant attention in the scene of classical photonics. In quantum optics, however, such rapid delay control systems for entangled photons have remained undeveloped. Here for the first time, we demonstrate rapid (2.5 MHz) modulation of signal-idler arrival times through electro-optic pump frequency modulation. Our technique applies the quantum phenomenon of nonlocal dispersion cancellation along with pump frequency tuning to control the relative delay between photon pairs. Chirped fiber Bragg gratings are employed to provide large amounts of dispersion which result in biphoton delays exceeding 30 ns. This rapid delay modulation scheme could be useful for on-demand single-photon distribution in addition to quantum versions of pulse position modulation.

  10. High-speed rapid single-flux-quantum (RSFQ) Batcher-banyan switching core

    NASA Astrophysics Data System (ADS)

    Zinoviev, Dmitry Y.

    1996-11-01

    We have carried out a paper feasibility study of the implementation of most common packet switching cores (crossbar, Batcher-banyan, time-division shared bus, and token ring) using the superconductor rapid single flux quantum (RSFQ) digital technology. According to our estimates, the best performance-to-complexity ratio may be obtained for the Batcher-banyan network. For example, a 128 by 128 switching core with self-routing (but without address translation, contention resolution, and broadcast features), consisting of about 180,000 Josephson junctions with the internal clock frequency of 60 GHz could handle a workload of 7.5 Tbps. This core could fit on a single 1 cm by 1 cm chip and dissipate as low as 45 mW. The estimated parameters are achievable using a simple 1.5-micrometer niobium- trilayer technology.

  11. Conceptual design of a high-speed electromagnetic switch for a modified flux-coupling-type SFCL and its application in renewable energy system.

    PubMed

    Chen, Lei; Chen, Hongkun; Yang, Jun; Shu, Zhengyu; He, Huiwen; Shu, Xin

    2016-01-01

    The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch's response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL's application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL's performance behaviors.

  12. Development of a High-Speed Static Switch for Distributed Energy and Microgrid Applications

    SciTech Connect

    Kroposki, B.; Pink, C.; Lynch, J.; John, V.; Meor Daniel, S.; Benedict, E.; Vihinen, I.

    2007-01-01

    Distributed energy resources can provide power to local loads in the electric distribution system and benefits such as improved reliability. Microgrids are intentional islands formed at a facility or in an electrical distribution system that contains at least one distributed resource and associated loads. Microgrids that operate both electrical generation and loads in a coordinated manner can offer additional benefits to the customer and local utility. The loads and energy sources can be disconnected from and reconnected to the area or local utility with minimal disruption to the local loads, thereby improving reliability. This paper details the development and testing of a highspeed static switch for distributed energy and microgrid applications.

  13. Localised polymer networks in chiral nematic liquid crystals for high speed photonic switching

    SciTech Connect

    Tartan, Chloe C. E-mail: steve.elston@eng.ox.ac.uk; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J. E-mail: steve.elston@eng.ox.ac.uk

    2016-05-14

    Self-assembled periodic structures based upon chiral liquid crystalline materials have significant potential in the field of photonics ranging from fast-switching optoelectronic devices to low-threshold lasers. The flexoelectro-optic effect, which is observed in chiral nematic liquid crystals (LCs) when an electric field is applied perpendicular to the helical axis, has significant potential as it exhibits analogue switching in 10–100 μs. However, the major technological barrier that prohibits the commercial realisation of this electro-optic effect is the requirement of a uniform, in-plane alignment of the helix axis between glass substrates. Here, it is shown that periodic polymer structures engineered in the nematic phase of a chiral nematic LC device using direct laser writing can result in the spontaneous formation of the necessary uniform lying helix (ULH) state. Specifically, two-photon polymerization is used in conjunction with a spatial light modulator so as to correct for aberrations introduced by the bounding glass substrates enabling the polymer structures to be fabricated directly into the device. The ULH state appears to be stable in the absence of an externally applied electric field, and the optimum contrast between the bright and dark states is obtained using polymer structures that have periodicities of the order of the device thickness.

  14. Localised polymer networks in chiral nematic liquid crystals for high speed photonic switching

    NASA Astrophysics Data System (ADS)

    Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

    2016-05-01

    Self-assembled periodic structures based upon chiral liquid crystalline materials have significant potential in the field of photonics ranging from fast-switching optoelectronic devices to low-threshold lasers. The flexoelectro-optic effect, which is observed in chiral nematic liquid crystals (LCs) when an electric field is applied perpendicular to the helical axis, has significant potential as it exhibits analogue switching in 10-100 μs. However, the major technological barrier that prohibits the commercial realisation of this electro-optic effect is the requirement of a uniform, in-plane alignment of the helix axis between glass substrates. Here, it is shown that periodic polymer structures engineered in the nematic phase of a chiral nematic LC device using direct laser writing can result in the spontaneous formation of the necessary uniform lying helix (ULH) state. Specifically, two-photon polymerization is used in conjunction with a spatial light modulator so as to correct for aberrations introduced by the bounding glass substrates enabling the polymer structures to be fabricated directly into the device. The ULH state appears to be stable in the absence of an externally applied electric field, and the optimum contrast between the bright and dark states is obtained using polymer structures that have periodicities of the order of the device thickness.

  15. Power applications of high-temperature superconductivity: Variable speed motors, current switches, and energy storage for end use

    SciTech Connect

    Hawsey, R.A.; Banerjee, B.B.; Grant, P.M.

    1996-08-01

    The objective of this project is to conduct joint research and development activities related to certain electric power applications of high-temperature superconductivity (HTS). The new superconductors may allow development of an energy-efficient switch to control current to variable speed motors, superconducting magnetic energy storage (SMES) systems, and other power conversion equipment. Motor types that were considered include induction, permanent magnet, and superconducting ac motors. Because it is impractical to experimentally alter certain key design elements in radial-gap motors, experiments were conducted on an axial field superconducting motor prototype using 4 NbTi magnets. Superconducting magnetic energy storage technology with 0.25--5 kWh stored energy was studied as a viable solution to short duration voltage sag problems on the customer side of the electric meter. The technical performance characteristics of the device wee assembled, along with competing technologies such as active power line conditioners with storage, battery-based uninterruptible power supplies, and supercapacitors, and the market potential for SMES was defined. Four reports were prepared summarizing the results of the project.

  16. Study of the effect of switching speed of the a-SiC/c-Si(p)-based, thyristor-like, ultra-high-speed switches, using two-dimensional simulation techniques

    NASA Astrophysics Data System (ADS)

    Dimitriadis, Evangelos I.; Georgoulas, Nikolaos

    2017-06-01

    A parametric study for a series of technological and geometrical parameters affecting rise time of Al/a-SiC/c-Si(p)/c-Si(n+)/Al thyristor-like switches, is presented here for the first time, using two-dimensional simulation techniques. By varying anode current values in simulation procedure we achieved very good agreement between simulation and experimental results for the rising time characteristics of the switch. A series of factors affecting the rising time of the switches are studied here. Two factors among all others studied here, exerting most significant influence, of more than one order of magnitude on the rising time, are a-SiC and c-Si(p) region widths, validating our earlier presented model for device operation. The above widths can be easily varied on device manufacture procedure. We also successfully simulated the rising time characteristics of our earlier presented simulated improved switch, with forward breakover voltage {V}{BF}=11 {{V}} and forward voltage drop {V}{{F}}=9.5 {{V}} at the ON state, exhibiting an ultra low rise time value of less than 10 ps, which in conjunction with its high anode current density values of 12 A/mm2 and also cheap and easy fabrication techniques, makes this switch appropriate for ESD protection as well as RF MEMS and NEMS applications.

  17. Reconfigurable high-speed optical fibre networks: Optical wavelength conversion and switching using VCSELs to eliminate channel collisions

    NASA Astrophysics Data System (ADS)

    Boiyo, Duncan Kiboi; Chabata, T. V.; Kipnoo, E. K. Rotich; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

    2017-01-01

    We experimentally provide an alternative solution to channel collisions through up-wavelength conversion and switching by using vertical cavity surface-emitting lasers (VCSELs). This has been achieved by utilizing purely optical wavelength conversion on VCSELs at the low attenuation, 1550 nm transmission window. The corresponding transmission and bit error-rate (BER) performance evaluation is also presented. In this paper, two 1550 nm VCSELs with 50-150 GHz channel spacing are modulated with a 10 Gb/s NRZ PRBS 27-1 data and their interferences investigated. A channel interference penalty range of 0.15-1.63 dB is incurred for 150-50 GHz channel spacing without transmission. To avoid channel collisions and to minimize high interference penalties, the transmitting VCSEL with data is injected into the side-mode of a slave VCSEL to obtain a new up converted wavelength. A 16 dB extinction ratio of the incoming wavelength is achieved when a 15 dBm transmitting beam is injected into the side-mode of a -4.5 dBm slave VCSEL. At 8.5 Gb/s, a 1.1 dB conversion and a 0.5 dB transmission penalties are realized when the converted wavelength is transmitted over a 24.7 km G.655 fibre. This work offers a low-cost, effective wavelength conversion and channel switching to reduce channel collision probability by reconfiguring channels at the node of networks.

  18. Structural characterization of neutral glycosphingolipids using high-performance liquid chromatography-electrospray ionization mass spectrometry with a repeated high-speed polarity and MSn switching system.

    PubMed

    Ito, Emi; Waki, Hiroaki; Miseki, Kozo; Shimada, Takashi; Sato, Taka-Aki; Kakehi, Kazuaki; Suzuki, Minoru; Suzuki, Akemi

    2013-12-01

    Four types of neutral glycosphingolipids (LacCer, Gb3Cer, Gb4Cer, and IV3αGalNAc-Gb4Cer; 10 pmol each) were analyzed using high-performance liquid chromatography (HPLC)-electrospray ionization quadrupole ion trap time-of-flight (ESI-QIT-TOF) mass spectrometry (MS) with a repeated high-speed polarity and MSn switching system. This system can provide six types of mass spectra, including positive and negative ion MS, MS2, and MS3 spectra, within 1 s per cycle. Using HPLC with a normal-phase column, information on the molecular weights of major molecular species of four neutral glycosphingolipids was obtained by detecting [M+Na]+ in the positive ion mode mass spectra and [M−H]− in the negative ion mode mass spectra. Sequences of glycosphingolipid oligosaccharide were obtained in the negative ion MS2 spectra. In addition, information on the ceramide structures was clearly obtained in the negative ion MS3 mass spectra. GlcCer molecular species were analyzed by HPLC-ESI-QIT-TOF MS with a reversed-phase column using 1 pmole of GlcCer. The structures of the seven molecular species of GlcCer, namely, d18:1-C16:0, d18:1-C18:0, d18:1-C20:0, d18:1-C22:0, d18:1-C23:0, d18:1-C24:1, and d18:1-C24:0, were characterized using positive ion MS and negative ion MS, MS2, and MS3. The established HPLC-ESI-QIT-TOF MS with MSn switching and a normal phase column has been successfully applied to the structural characterization of LacCer and Gb4Cer in a crude mixture prepared from human erythrocytes.

  19. A Precision and High-Speed Behavioral Simulation Method for Transient Response and Frequency Characteristics of Switching Converters

    NASA Astrophysics Data System (ADS)

    Sai, Toru; Sugimoto, Shoko; Sugimoto, Yasuhiro

    We propose a fast and precise transient response and frequency characteristics simulation method for switching converters. This method uses a behavioral simulation tool without using a SPICE-like analog simulator. The nonlinear operation of the circuit is considered, and the nonlinear function is realized by defining the nonlinear formula based on the circuit operation and by applying feedback. To assess the accuracy and simulation time of the proposed simulation method, we designed current-mode buck and boost converters and fabricated them using a 0.18-µm high-voltage CMOS process. The comparison in the transient response and frequency characteristics among SPICE, the proposed program on a behavioral simulation tool which we named NSTVR (New Simulation Tool for Voltage Regulators) and experiments of fabricated IC chips showed good agreement, while NSTVR was more than 22 times faster in transient response and 85 times faster in frequency characteristics than SPICE in CPU time in a boost converter simulation.

  20. A Study of Quality of Service Communication for High-Speed Packet-Switching Computer Sub-Networks

    NASA Technical Reports Server (NTRS)

    Cui, Zhenqian

    1999-01-01

    With the development of high-speed networking technology, computer networks, including local-area networks (LANs), wide-area networks (WANs) and the Internet, are extending their traditional roles of carrying computer data. They are being used for Internet telephony, multimedia applications such as conferencing and video on demand, distributed simulations, and other real-time applications. LANs are even used for distributed real-time process control and computing as a cost-effective approach. Differing from traditional data transfer, these new classes of high-speed network applications (video, audio, real-time process control, and others) are delay sensitive. The usefulness of data depends not only on the correctness of received data, but also the time that data are received. In other words, these new classes of applications require networks to provide guaranteed services or quality of service (QoS). Quality of service can be defined by a set of parameters and reflects a user's expectation about the underlying network's behavior. Traditionally, distinct services are provided by different kinds of networks. Voice services are provided by telephone networks, video services are provided by cable networks, and data transfer services are provided by computer networks. A single network providing different services is called an integrated-services network.

  1. High Power Switching Transistor

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Kao, Y. C.; Carnahan, D. C.

    1983-01-01

    Improved switching transistors handle 400-A peak currents and up to 1,200 V. Using large diameter silicon wafers with twice effective area as D60T, form basis for D7 family of power switching transistors. Package includes npn wafer, emitter preform, and base-contact insert. Applications are: 25to 50-kilowatt high-frequency dc/dc inverters, VSCF converters, and motor controllers for electrical vehicles.

  2. High optical switching speed and flexible electrochromic display based on WO3 nanoparticles with ZnO nanorod arrays' supported electrode.

    PubMed

    Wang, Mingjun; Fang, Guojia; Yuan, Longyan; Huang, Huihui; Sun, Zhenhua; Liu, Nishuang; Xia, Shanhong; Zhao, Xingzhong

    2009-05-06

    The electrochromic (EC) property of WO(3) nanoparticles grown on vertically self-aligned ZnO nanorods (ZNRs) is reported. An electrochromic character display based on WO(3) nanoparticle-modified ZnO nanorod arrays on a flexible substrate has been fabricated and demonstrated. The ZNRs were first synthesized on ZnO-seed-coated In(2)O(3):Sn (ITO) glass (1 cm(2) cell) and polyethylene terephthalate (PET) (4 cm(2) cell) substrates by a low temperature hydrothermal method, and then amorphous WO(3) nanoparticles were grown directly on the surface of the ZNRs by the pulsed laser deposition (PLD) method. The ZNR-based EC device shows high transparence, good electrochromic stability and fast switching speed (4.2 and 4 s for coloration and bleaching, respectively, for a 1 cm(2) cell). The good performance of the ZNR electrode-based EC display can be attributed to the large surface area, high crystallinity and good electron transport properties of the ZNR arrays. Its high contrast, fast switching, good memory and flexible characteristics indicate it is a promising candidate for flexible electrochromic displays or electronic paper.

  3. High PRF high current switch

    DOEpatents

    Moran, Stuart L.; Hutcherson, R. Kenneth

    1990-03-27

    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  4. Unipolar poling-induced high switching speed and improved imprint behaviors for poly(vinylidene fluoride-trifluoroethylene) copolymer ultrathin films

    NASA Astrophysics Data System (ADS)

    Hou, Ying; Lü, Zhaoyue; Pu, Tiansong; Zhang, Yuan; Meng, Xiangjian; Xu, Haisheng

    2013-12-01

    The polarization switching and imprint behaviors with different pulse and unipolar poling processes for ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer ultrathin films have been studied. Compared with results for samples only through the certain protocol we studied previously, the much faster switching speed and lower voltage shift are observed for films with certain protocol as well as certain unipolar poling. The analyses show that these properties are strongly dependent on the directions of the switching and unipolar poling field. The results provide another effective route to design the optimum protocol for ferroelectric random access memory based on P(VDF-TrFE) copolymer ultrathin film.

  5. Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

    DOEpatents

    He, Jianliang; Rote, Donald M.

    1996-01-01

    A stabilization and propulsion system comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the super conducting magnets on the vehicle.

  6. Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

    DOEpatents

    He, J.; Rote, D.M.

    1996-05-21

    A stabilization and propulsion system are disclosed comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the superconducting magnets on the vehicle. 12 figs.

  7. 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.

  8. 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

  9. Demonstration of 20Gb/s polarization-insensitive wavelength switching system for high-speed free-space optical network

    NASA Astrophysics Data System (ADS)

    Qian, Feng-chen; Ye, Ya-lin; Wen, Yu; Duan, Tao; Feng, Huan

    2015-10-01

    A 20Gb/s polarization-insensitive all-optical wavelength switching system for high-speed free-space optical communication (FSO) network is experimentally demonstrated All-optical wavelength conversion (AOWC) is implemented using four-wave mixing (FWM) by highly-nonlinear fiber (HNLF). In the experimental setup, a simple actively mode-locked fiber ring laser (AML-FRL) with repetition frequency from 1 to 15 GHz is used to generate eight 2.5Gb/s tributary signals, which are multiplexed into one 20Gb/s optical data stream. At the receiver, the 20 Gb/s OTDM data stream is demultiplexed down to 2.5 Gb/s via a polarization-insensitive FWM scheme. The whole space communication distance is over 10 meters in building hallway. The experimental results show that this system can stably run over 24 hours at 10-9 BER level, thus the proposed architecture can work at higher rate with wavelength-division multiplexing (WDM) and high order modulation schemes.

  10. High-speed cutting of thin materials with a Q-switched laser in a water-jet versus conventional laser cutting with a free running laser

    NASA Astrophysics Data System (ADS)

    Wagner, Frank R.; Boillat, Christophe; Buchilly, Jean-Marie; Spiegel, Akos; Vago, Nandor; Richerzhagen, Bernold

    2003-07-01

    Cutting of thin material, c.f. stencils, stents and thin wafers, is an important market for laser machining. Traditionally this task is performed using flash-lamp pumped, free-running Nd:YAG lasers. Using the water-jet guided laser technology, we experienced that the use of Q-switched lasers leads to superior results while cutting a variety of thin materials. In this technique, the laser is conducted to the work piece by total internal reflection in a thin stable water-jet, comparable to the core of an optical fiber. Utilizing this system, we obtain burr-free, slightly tapered cuts at the same speed as the classical laser cutting and without distinguishable heat affected zone. The main difference is, except the water-jet usage, the pulse duration which is approximately 400 ns instead of 20 to 200 μs in the case of free running lasers. Up to 40'000 high quality apertures per hour can be achieved in stencil mask cutting with the new system. We will compare qualitatively the two possibilities: conventional laser cutting with free-running lasers and water-jet guided laser cutting with Q-switched lasers. The results will be discussed in terms of the different physical effects involved in the material removal upon both methods. In particular the importance of molten material expulsion by the water-jet will be pointed out and compared to the action of the assist-gas. The mentioned effects show that the combination of short pulse laser and water-jet will be beneficial for the production of a wide range of precision parts.

  11. An anti-ferroelectric gated Landau transistor to achieve sub-60 mV/dec switching at low voltage and high speed

    NASA Astrophysics Data System (ADS)

    Karda, Kamal; Jain, Ankit; Mouli, Chandra; Alam, Muhammad Ashraful

    2015-04-01

    Landau field effect transistors promise to lower the power-dissipation of integrated circuits (ICs) by reducing the subthreshold swing (S) below the Boltzmann limit of 60 mV/dec. The key idea is to replace the classical gate insulator with dielectrics that exhibit negative capacitance (NC) associated with double-well energy landscape, for example, ferroelectrics (FE), air-gap capacitors, or a combination thereof. Indeed, S is dramatically reduced, constrained only by the limits of hysteresis-free operation. Unfortunately, the following limitations apply (i) the need for capacitance matching constrains steep S only to the small subthreshold region for FE based negative capacitance field effect transistor (NCFET) and requires an insulator too thick for sub-20 nm scaling; (ii) the kinetics of mechanical switching for airgap based NCFET obviate high-speed operation; and (iii) the lattice mismatch between the substrate and the dielectric makes defect-free integration difficult. In this article, we demonstrate that a FET integrated with 10 nm HfO2-based anti-ferroelectric and FE hetero stack would achieve ultralow S with ON-current ( Io n) at par with classical transistors at significantly lower voltage and would simplify integration. Our results address the well-known challenges/criticisms of classical Landau transistors, thereby, making them technology relevant for modern ICs.

  12. High voltage coaxial switch

    DOEpatents

    Rink, John P.

    1983-07-19

    A coaxial high voltage, high current switch having a solid cylindrical cold cathode coaxially surrounded by a thin hollow cylindrical inner electrode and a larger hollow cylindrical outer electrode. A high voltage trigger between the cathode and the inner electrode causes electrons to be emitted from the cathode and flow to the inner electrode preferably through a vacuum. Some of the electrons penetrate the inner electrode and cause a volumetric discharge in the gas (which may be merely air) between the inner and outer electrodes. The discharge provides a low impedance path between a high voltage charge placed on the outer electrode and a load (which may be a high power laser) coupled to the inner electrode. For high repetition rate the gas between the inner and outer electrodes may be continuously exchanged or refreshed under pressure.

  13. High voltage coaxial switch

    DOEpatents

    Rink, J.P.

    1983-07-19

    A coaxial high voltage, high current switch having a solid cylindrical cold cathode coaxially surrounded by a thin hollow cylindrical inner electrode and a larger hollow cylindrical outer electrode. A high voltage trigger between the cathode and the inner electrode causes electrons to be emitted from the cathode and flow to the inner electrode preferably through a vacuum. Some of the electrons penetrate the inner electrode and cause a volumetric discharge in the gas (which may be merely air) between the inner and outer electrodes. The discharge provides a low impedance path between a high voltage charge placed on the outer electrode and a load (which may be a high power laser) coupled to the inner electrode. For high repetition rate the gas between the inner and outer electrodes may be continuously exchanged or refreshed under pressure. 3 figs.

  14. 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.

  15. 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.}

  16. 25-Gbit/s burst-mode optical receiver using high-speed avalanche photodiode for 100-Gbit/s optical packet switching.

    PubMed

    Nada, Masahiro; Nakamura, Makoto; Matsuzaki, Hideaki

    2014-01-13

    25-Gbit/s error-free operation of an optical receiver is successfully demonstrated against burst-mode optical input signals without preambles. The receiver, with a high-sensitivity avalanche photodiode and burst-mode transimpedance amplifier, exhibits sufficient receiver sensitivity and an extremely quick response suitable for burst-mode operation in 100-Gbit/s optical packet switching.

  17. Buffer allocation in an ATM switch with output buffer and speed constraints

    NASA Astrophysics Data System (ADS)

    Gupta, Anil K.; Georganas, N. D.

    A synchronous nonblocking N times N switch for asynchronous transfer mode (ATM) networks or high speed packet switching networks transporting fixed length packets called cells is considered. Such a switch with output queuing achieves the optimal performance, however it requires the switch fabric to work at the speed of N. In practice the switch may operate L times faster than the input/output trunk. It is assumed that queues at each output port have a limited buffer space and whenever an output queue is full, the back-pressure is applied and the packets are retained at the head of the input queues. The upper bound on the packet loss probability at the input queues in such a switch are computed. To achieve a given packet loss rate, the switch with L equals 2 requires almost the same amount of input and output buffers as with L equals 4 up to 70 percent input load, but as the load increases beyond 70 percent the switch with L equals 4 would require more output buffers and less input buffers in comparison with a switch operating at L equals 2. The performance of a switch with L equals 3 is very similar to that for L equals 4 and is not considered.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. High-speed optical beam alignment based on a motion control technique for three-dimensional microelectromechanical systems optical switch modules

    NASA Astrophysics Data System (ADS)

    Mizukami, Masato; Yamaguchi, Joji; Nemoto, Naru

    2011-07-01

    For optical axis alignment when light deflection control of a MEMS mirror is done at high speed, we propose a method based on identifying the quadratic surface shape. The method uses information about the optical power monitored when the mirror is inclined to a small angle. It is shown that the search for maximum optical power is possible by using this method. We also designed a control system with a band-stop filter for resonance frequency to decrease residual vibration generated when the mirror is moved at high speed. We confirm that the searchable level of optical power can be improved.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Optically controlled waveplate at a telecom wavelength using a ladder transition in Rb atoms for all-optical switching and high speed Stokesmetric imaging.

    PubMed

    Krishnamurthy, Subramanian; Tu, Y; Wang, Y; Tseng, S; Shahriar, M S

    2014-11-17

    We demonstrate an optically controlled waveplate at ~1323 nm using the 5S(1/2)-5P(1/2)-6S(1/2) ladder transition in a Rb vapor cell. The lower leg of the transitions represents the control beam, while the upper leg represents the signal beam. We show that we can place the signal beam in any arbitrary polarization state with a suitable choice of polarization of the control beam. Specifically, we demonstrate a differential phase retardance of ~180 degrees between the two circularly polarized components of a linearly polarized signal beam. We also demonstrate that the system can act as a Quarter Wave plate. The optical activity responsible for the phase retardation process is explained in terms of selection rules involving the Zeeman sublevels. As such, the system can be used to realize a fast Stokesmetric imaging system with a speed of ~3 MHz. When implemented using a tapered nano fiber embedded in a vapor cell, this system can be used to realize an ultra-low power all-optical switch as well as a Quantum Zeno Effect based all-optical logic gate by combining it with an optically controlled polarizer, previously demonstrated by us. We present numerical simulations of the system using a comprehensive model which incorporates all the relevant Zeeman sub-levels in the system, using a novel algorithm recently developed by us for efficient computation of the evolution of an arbitrary large scale quantum system.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. High speed optical networks

    NASA Astrophysics Data System (ADS)

    Frankel, Michael Y.; Livas, Jeff

    2005-02-01

    unregenerated reach. More sophisticated optical amplifiers provide lower noise for increased reach and increased spectral bandwidth for higher wavelength count lower wavelength blocking probability. Optical analog networks also require methods for mitigating optical power transients, for controlling optical spectral flatness, and for dynamically managing changes (e.g. in chromatic dispersion and polarization mode dispersion.) Since signals stay in the optical domain, optical performance monitoring techniques are required for fault isolation and correction. Efficient routing of optical signals also requires sophisticated switching nodes with an ability to selectively steer optical signals into several directions with single-channel spectral granularity. Most of these technologies are not modular and require interruption of service if not deployed at the initial system installation, thereby increasing first install costs substantially, even if initial capacity loading is small. Further, validation of systems and software targeting a specific network design is complex. Only a small fraction of the total network may be reasonably reproduced in the lab, and many field configurations are not predictable or even dynamic. Thus, extra system margin has to be allocated to handle the behavior uncertainty. To constrain the complexity of both hardware technology and software algorithms, regions of network transparency can be established with OEO forced at perimeters. Thus, "analog" regions are surrounded by "digital" interfaces. Following are some example tradeoffs that will be discussed. What is a good modulation format choice, and does increased reach and impairment resiliency justify hardware and controls that are more complicated? What are reasonable amplifier choices to make under specific network assumptions? Can high transport system capacity be leveraged to simplify optical switch node design by reducing spectral efficiency?

  18. High gain GaAs photoconductive semiconductor switches: Switch longevity

    SciTech Connect

    Loubriel, G.M.; Zutavern, F.J.; Mar, A.

    1998-07-01

    Optically activated, high gain GaAs switches are being tested for many different pulsed power applications that require long lifetime (longevity). The switches have p and n contact metallization (with intentional or unintentional dopants) configured in such a way as to produce p-i-n or n-i-n switches. The longevity of the switches is determined by circuit parameters and by the ability of the contacts to resist erosion. This paper will describe how the switches performed in test-beds designed to measure switch longevity. The best longevity was achieved with switches made with diffused contacts, achieving over 50 million pulses at 10 A and over 2 million pulses at 80 A.

  19. High Power Switch Development.

    DTIC Science & Technology

    1979-11-29

    LUBBOCK Unclassified SECURITY €! ION 0 THIS PAGE (When Doat Entered) E RT DOCUMENTATION PAGE READ INSTRUCTONS9 . , -- RBEFORE COMPLETIDG FORM off...investigations, we used the electrodes in an Ion Physics Corp. FX-15 generator made available to us by the AFWL. Considerable modifications were necessary...the high pressure vessel of such as fusion, the production of high energy- the Ion Physics Corporation FX-15 (Fig 2). The particle beams, and the

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. High power ferrite microwave switch

    NASA Technical Reports Server (NTRS)

    Bardash, I.; Roschak, N. K.

    1975-01-01

    A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

  5. High-speed ablation of ultradeep channels by a phase-conjugate dynamically controlled passively Q-switched Nd:YAG laser

    SciTech Connect

    Basiev, T T; Garnov, S V; Klimentov, S M; Pivovarov, P A; Gavrilov, A V; Smetanin, S N; Solokhin, S A; Fedin, A V

    2007-10-31

    Parameters of high-speed ablation of ultradeep channels by controlled pulse trains from a single-mode phase-conjugate dynamic cavity Nd:YAG laser emitting 20-200-ns, 70-250-mJ pulses at a pulse repetition rate in a train of 40-250 kHz are studied. The optimal parameters of ablation are found, for which a long-lived region of a hot rarefied gas was maintained in the ultradeep channel, which suppressed the shielding action of the surface plasma. The control of the lasing process during ablation optimises not only the heating and plasma formation, but also the removal of the processed material in the pause between laser pulses. Adaptive regulation of lasing parameters during ablation made it possible to obtain ultradeep channels of length 8-27 mm and diameters 80-300 {mu}m of the input and output holes in metals (aluminium, steel and Inconel 718 nickel superalloy) and ultrahard ceramics (Al{sub 2}O{sub 3}, AlN, SiC). (special issue devoted to the 25th anniversary of the a.m. prokhorov general physics institute)

  6. 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

  7. A Close Loop Low-Power and High Speed 130 nm CMOS Sample and Hold Circuit Based on Switched Capacitor for ADC Module

    NASA Astrophysics Data System (ADS)

    Nasir, Z.; Ruslan, S. H.

    2017-08-01

    A sample and hold (S/H) block is typically used as an analogue to digital interface in the analogue to digital converter (ADC) system. Since ADC is widely used in processing signals, the power consumption of the ADC must be lowered to conserve energy. Therefore the S/H circuit must be of a low powered too. Sampling phase and hold phase are the two phases of the operation cycle of the S/H circuit. Switched capacitor (SC) techniques have been developed in order to allow the integration on a single silicon chip of both digital and analogue functions. By controlling switches around the SC, the SC circuit works by passing charge into and out of a capacitor. SC circuits are suitable for on chip implementations because they replace a resistor with switches and capacitors. In this research, a closed-loop sample and hold circuit based on SC is designed and simulated with Cadence EDA tools. The schematic, layout, and simulation of the circuit is done using generic Silterra 130 nm technology file. All the analysis is done using Virtuoso Analog Design Environment. Layout and schematic are drawn using Virtuoso Schematic Editor and Virtuoso Layout Editor, Calibre is used for post layout simulation. The closed loop S/H circuit based on SC is successfully designed and able to sample and hold the analogue input waveform. The power consumption of the circuit is 0.919 mW and the propagation delay is 64.96 ps.

  8. A high capacity satellite switched TDMA microwave switch matrix

    NASA Technical Reports Server (NTRS)

    Cory, B. J.; Berkowitz, M.

    1981-01-01

    A description is given of the conceptual design of a high-capacity satellite switched-time division multiple access (SS-TDMA) microwave switch matrix fabricated with GaAs monolithic microwave integrated circuits (MMICs), including integration of both microwave and control logic circuits into the monolithic design. The technology required for a 30/20 GHz communications system includes an on-board SS-TDMA switch matrix. A conceptual design study that has been completed for a wideband, high-capacity (typically 100 x 100) channel switch matrix using technology anticipated for 1987 is described, noting that the study resulted in a switch matrix design concept using a coupled crossbar architecture implemented with MMIC. The design involves basic building block MMIC, permitting flexible growth and efficient wraparound redundancy to increase reliability.

  9. Photoconductive switching for high power microwave generation

    SciTech Connect

    Pocha, M.D.; Hofer, W.W.

    1990-10-01

    Photoconductive switching is a technology that is being increasingly applied to generation of high power microwaves. Two primary semiconductors used for these devices are silicon and gallium arsenide. Diamond is a promising future candidate material. This paper discusses the important material parameters and switching modes, critical issues for microwave generation, and future directions for this high power, photoconductive switching technology.

  10. High-speed and low-energy nitride memristors

    DOE PAGES

    Choi, Byung Joon; Torrezan, Antonio C.; Strachan, John Paul; ...

    2016-05-24

    High-performance memristors based on AlN films have been demonstrated, which exhibit ultrafast ON/OFF switching times (≈85 ps for microdevices with waveguide) and relatively low switching current (≈15 μA for 50 nm devices). Physical characterizations are carried out to understand the device switching mechanism, and rationalize speed and energy performance. The formation of an Al-rich conduction channel through the AlN layer is revealed. Here, the motion of positively charged nitrogen vacancies is likely responsible for the observed switching.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Air-bridge and Vertical CNT Switches for High Performance Switching Applications

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Wong, Eric W.; Epp, Larry; Bronikowski, Michael J.; Hunt, BBrian D.

    2006-01-01

    Carbon nanotubes are attractive for switching applications since electrostatically-actuated CNT switches have low actuation voltages and power requirements, while allowing GHz switching speeds that stem from the inherently high elastic modulus and low mass of the CNT.Our first NEM structure, the air-bridge switch, consists of suspended single-walled nanotubes (SWNTs) that lie above a sputtered Nb base electrode, where contact to the CNTs is made using evaporated Au/Ti. Electrical measurements of these air-bridge devices show well-defined ON and OFF states as a dc bias of a few volts is applied between the CNT and the Nb-base electrode. The CNT air-bridge switches were measured to have switching times down to a few nanoseconds. Our second NEM structure, the vertical CNT switch, consists of nanotubes grown perpendicular to the substrate. Vertical multi-walled nanotubes (MWNTs) are grown directly on a heavily doped Si substrate, from 200 - 300 nm wide, approximately 1 micrometer deep nano-pockets, with Nb metal electrodes to result in the formation of a vertical single-pole-double-throw switch architecture.

  16. Study of switching transients in high frequency converters

    NASA Astrophysics Data System (ADS)

    Zinger, Donald S.; Elbuluk, Malik E.; Lee, Tony

    1993-06-01

    As the semiconductor technologies progress rapidly, the power densities and switching frequencies of many power devices are improved. With the existing technology, high frequency power systems become possible. Use of such a system is advantageous in many aspects. A high frequency ac source is used as the direct input to an ac/ac pulse-density-modulation (PDM) converter. This converter is a new concept which employs zero voltage switching techniques. However, the development of this converter is still in its infancy stage. There are problems associated with this converter such as a high on-voltage drop, switching transients, and zero-crossing detecting. Considering these problems, the switching speed and power handling capabilities of the MOS-Controlled Thyristor (MCT) makes the device the most promising candidate for this application. A complete insight of component considerations for building an ac/ac PDM converter for a high frequency power system is addressed. A power device review is first presented. The ac/ac PDM converter requires switches that can conduct bi-directional current and block bi-directional voltage. These bi-directional switches can be constructed using existing power devices. Different bi-directional switches for the converter are investigated. Detailed experimental studies of the characteristics of the MCT under hard switching and zero-voltage switching are also presented. One disadvantage of an ac/ac converter is that turn-on and turn-off of the switches has to be completed instantaneously when the ac source is at zero voltage. Otherwise shoot-through current or voltage spikes can occur which can be hazardous to the devices. In order for the devices to switch softly in the safe operating area even under non-ideal cases, a unique snubber circuit is used in each bi-directional switch. Detailed theory and experimental results for circuits using these snubbers are presented.

  17. Study of switching transients in high frequency converters

    NASA Technical Reports Server (NTRS)

    Zinger, Donald S.; Elbuluk, Malik E.; Lee, Tony

    1993-01-01

    As the semiconductor technologies progress rapidly, the power densities and switching frequencies of many power devices are improved. With the existing technology, high frequency power systems become possible. Use of such a system is advantageous in many aspects. A high frequency ac source is used as the direct input to an ac/ac pulse-density-modulation (PDM) converter. This converter is a new concept which employs zero voltage switching techniques. However, the development of this converter is still in its infancy stage. There are problems associated with this converter such as a high on-voltage drop, switching transients, and zero-crossing detecting. Considering these problems, the switching speed and power handling capabilities of the MOS-Controlled Thyristor (MCT) makes the device the most promising candidate for this application. A complete insight of component considerations for building an ac/ac PDM converter for a high frequency power system is addressed. A power device review is first presented. The ac/ac PDM converter requires switches that can conduct bi-directional current and block bi-directional voltage. These bi-directional switches can be constructed using existing power devices. Different bi-directional switches for the converter are investigated. Detailed experimental studies of the characteristics of the MCT under hard switching and zero-voltage switching are also presented. One disadvantage of an ac/ac converter is that turn-on and turn-off of the switches has to be completed instantaneously when the ac source is at zero voltage. Otherwise shoot-through current or voltage spikes can occur which can be hazardous to the devices. In order for the devices to switch softly in the safe operating area even under non-ideal cases, a unique snubber circuit is used in each bi-directional switch. Detailed theory and experimental results for circuits using these snubbers are presented. A current regulated ac/ac PDM converter built using MCT's and IGBT's is

  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 VOLTAGE, HIGH CURRENT SPARK GAP SWITCH

    DOEpatents

    Dike, R.S.; Lier, D.W.; Schofield, A.E.; Tuck, J.L.

    1962-04-17

    A high voltage and current spark gap switch comprising two main electrodes insulatingly supported in opposed spaced relationship and a middle electrode supported medially between the main electrodes and symmetrically about the median line of the main electrodes is described. The middle electrode has a perforation aligned with the median line and an irradiation electrode insulatingly supported in the body of the middle electrode normal to the median line and protruding into the perforation. (AEC)

  20. W-band exciter delivers fast switching speed

    NASA Astrophysics Data System (ADS)

    Oleson, Chuk; Archdale, Anthony

    1990-10-01

    Millimeter-wave radar systems used in target discrimination applications require exciters that provide fast frequency switching, excellent phase noise, and fast pulse rise and fall times. A 512-channel W-band exciter design that uses MMIC oscillators and amplifiers and IF phase-locking techniques provides frequency switching with less than 1-microsec setting time and 2-deg absolute phase coherency.

  1. Pulse switching for high energy lasers

    NASA Technical Reports Server (NTRS)

    Laudenslager, J. B.; Pacala, T. J. (Inventor)

    1981-01-01

    A saturable inductor switch for compressing the width and sharpening the rise time of high voltage pulses from a relatively slow rise time, high voltage generator to an electric discharge gas laser (EDGL) also provides a capability for efficient energy transfer from a high impedance primary source to an intermediate low impedance laser discharge network. The switch is positioned with respect to a capacitive storage device, such as a coaxial cable, so that when a charge build-up in the storage device reaches a predetermined level, saturation of the switch inductor releases or switches energy stored in the capactive storage device to the EDGL. Cascaded saturable inductor switches for providing output pulses having rise times of less than ten nanoseconds and a technique for magnetically biasing the saturable inductor switch are disclosed.

  2. 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.

  3. 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.

  4. High-performance quantitative robust switching control for optical telescopes

    NASA Astrophysics Data System (ADS)

    Lounsbury, William P.; Garcia-Sanz, Mario

    2014-07-01

    This paper introduces an innovative robust and nonlinear control design methodology for high-performance servosystems in optical telescopes. The dynamics of optical telescopes typically vary according to azimuth and altitude angles, temperature, friction, speed and acceleration, leading to nonlinearities and plant parameter uncertainty. The methodology proposed in this paper combines robust Quantitative Feedback Theory (QFT) techniques with nonlinear switching strategies that achieve simultaneously the best characteristics of a set of very active (fast) robust QFT controllers and very stable (slow) robust QFT controllers. A general dynamic model and a variety of specifications from several different commercially available amateur Newtonian telescopes are used for the controller design as well as the simulation and validation. It is also proven that the nonlinear/switching controller is stable for any switching strategy and switching velocity, according to described frequency conditions based on common quadratic Lyapunov functions (CQLF) and the circle criterion.

  5. High average power switching for linear accelerators

    NASA Astrophysics Data System (ADS)

    Dicapua, M. S.

    This report summarizes the presentations and the findings of the Workshop on High Average Power Switching (WHAPS) that took place in Livermore, California, on October 10 to 11, 1990. The WHAPS discussed switching technologies that could meet requirements that arise in applications of linear induction accelerators also known as induction linacs. Induction linacs require a switch that will hold-off 250 kV, conduct 30 kA for 150 to 200 ns, operate at 1 to 2 kHz for several second bursts, have better than 1 ns jitter, and last in excess of 10(exp 8) pulses. The workshop reviewed the state-of-the-art of Super-Emissive Cathode Switches, Magnetically Delayed Vacuum Switches and Solid State Switches and considered research and development steps that would allow these technologies to meet these requirements.

  6. Diamond switches for high temperature electronics

    SciTech Connect

    Prasad, R.R.; Rondeau, G.; Qi, Niansheng

    1996-04-25

    Diamond switches are well suited for use in high temperature electronics. Laboratory feasibility of diamond switching at 1 kV and 18 A was demonstrated. DC blocking voltages up to 1 kV were demonstrated. A 50 {Omega} load line was switched using a diamond switch, with switch on-state resistivity {approx}7 {Omega}-cm. An electron beam, {approx}150 keV energy, {approx}2 {mu}s full width at half maximum was used to control the 5 mm x 5 mm x 100 {mu}m thick diamond switch. The conduction current temporal history mimics that of the electron beam. These data were taken at room temperature.

  7. High power solid state switches

    NASA Astrophysics Data System (ADS)

    Gundersen, Martin

    1991-11-01

    We have successfully produced an optically triggered thyristor based in Gallium Arsenide, developed a model for breakdown, and are developing two related devices, including a Gallium Arsenide based static inductor thyristor. We are getting at the basic limitations of Gallium Arsenide for these applications, and are developing models for the physical processes that will determine device limitations. The previously supported gas phase work - resulting in the back-lighted thyratron (BLT) - has actually resulted in a very changed view of how switching can be accomplished, and this is impacting the design of important machines. The BLT is being studied internationally: in Japan for laser fusion and laser isotope separation. ITT has built a BLT that has switched 30 kA at 60 kV in testing at NSWC Dahlgren and the device is being commercialized by another American company. Versions of the switch are now being tested for excimer laser and other applications. Basically, the switch, which arose from pulse power physics studies at USC, can switch more current faster (higher di/dt), with less housekeeping, and with other advantageous properties. There are a large number of other new applications, include kinetic energy weapons, pulsed microwave sources and R.F. accelerators.

  8. Picosecond High Pressure Gas Switch experiment

    SciTech Connect

    Cravey, W.R.; Freytag, E.K.; Goerz, D.A.; Poulsen, P.; Pincosy, P.A.

    1993-08-01

    A high Pressure Gas Switch has been developed and tested at LLNL. Risetimes on the order of 200 picoseconds have been observed at 1 kHz prf and 1 atmosphere pressures. Calculations show that switching closure times on the order of tens of picoseconds can be achieved at higher pressures and electric fields. A voltage hold-off of 1 MV/cm has been measured at 10 atmospheres and several MV/cm appears possible with the HPGS. With such high electric field levels, energy storage of tens of Joules in a reasonably sized package is achievable. Initial HPGS performance has been characterized using the WASP pulse generator at LLNL. A detailed description of the switch used for initial testing is given. Switch recovery times of 1-ms have been measured at 1 atmosphere. Data on the switching uniformity, voltage hold-off recovery, and pulse repeatability, is presented. In addition, a physics switch model is described and results are compared with experimental data. Modifications made to the WASP HV pulser in order to drive the HPGS will also be discussed. Recovery times of less than 1 ms were recorded without gas flow in the switch chambers. Low pressure synthetic air was used as the switch dielectric. Longer recovery times were required when it was necessary to over-voltage the switch.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. High-explosive driven crowbar switch

    DOEpatents

    Dike, Robert S.; Kewish, Jr., Ralph W.

    1976-01-13

    The disclosure relates to a compact explosive driven switch for use as a low resistance, low inductance crowbar switch. A high-explosive charge extrudes a deformable conductive metallic plate through a polyethylene insulating layer to achieve a hard current contact with a supportive annular conductor.

  14. 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.

  15. 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.

  16. High voltage MOSFET switching circuit

    DOEpatents

    McEwan, Thomas E.

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  17. High voltage MOSFET switching circuit

    DOEpatents

    McEwan, T.E.

    1994-07-26

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET. 2 figs.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. High voltage photoconductive switch package

    SciTech Connect

    Caporaso, George J.

    2016-11-22

    A photoconductive switch having a wide bandgap material substrate between opposing electrodes, and a doped dielectric filler that is in contact with both the electrodes and the substrate at the triple point. The dielectric filler material is doped with a conductive material to make it partially or completely conducting, to minimize the field enhancement near the triple point both when the substrate is not conducting in the "off" state and when the substrate is rendered conducting by radiation in the "on" state.

  3. A Comparison of High-Voltage Switches

    SciTech Connect

    Chu, K.W.; Scott, G.L.

    1999-02-01

    This report summarizes our work on high-voltage switches during the past few years. With joint funding from the Department of Energy (DOE) and the Department of Defense (DOD), we tested a wide variety of switches to a common standard. This approach permitted meaningful comparisons between disparate switches. Most switches were purchased from commercial sources, though some were experimental devices. For the purposes of this report, we divided the switches into three generic types (gas, vacuum, and semiconductor) and selected data that best illustrates important strengths and weaknesses of each switch type. Test techniques that indicate the state of health of the switches are emphasized. For example, a good indicator of residual gas in a vacuum switch is the systematic variation of the switching delay in response to changes in temperature and/or operating conditions. We believe that the presentation of this kind of information will help engineers to select and to test switches for their particular applications. Our work was limited to switches capable of driving slappers. Also known as exploding-foil initiators, slappers are detonators that initiate a secondary explosive by direct impact with a small piece of matter moving at the detonation velocity (several thousands of meters per second). A slapper is desirable for enhanced safety (no primary explosive), but it also places extra demands on the capacitor-discharge circuit to deliver a fast-rising current pulse (greater than 10 A/ns) of several thousand amperes. The required energy is substantially less than one joule; but this energy is delivered in less than one microsecond, taking the peak power into the megawatt regime. In our study, the switches operated in the 1 kV to 3 kV range and were physically small, roughly 1 cm{sup 3} or less. Although a fuze functions only once in actual use, multiple-shot capability is important for production testing and for research work. For this reason, we restricted this report

  4. Fast vortex core switching at high temperatures

    NASA Astrophysics Data System (ADS)

    Lebecki, Kristof M.; Legut, Dominik

    2016-08-01

    Fast ferromagnetic vortex core switching is investigated employing micromagnetic simulations. Short pulse (in the range of a few hundreds of picoseconds) of an in-plane oscillating magnetic field is applied to a thin disk (diameter 200 nm and thickness 20 nm) with material parameters resembling permalloy. Fundamental frequency of this excitation field is close to the resonance with the material spin waves. Thermal effects are introduced by replacing the Landau-Lifshitz-Gilbert equation by the Landau-Lifshitz-Bloch equation. Temperature from 300 K to 850 K is considered, just below the Curie temperature TC = 870 K. Calculations are done within the OOMMF simulation framework. We find that: (i) Period of the field necessary to switch the vortex increases approximately from 141 ps at 300 K to 572 ps for the high-temperature limit. (ii) Amplitude of the field necessary to switch the vortex core decreases roughly from 60 mT to 15 mT - even at high temperatures this amplitude is nonzero, contrary to the case of quasi-static switching. (iii) Time span between the excitation and switching (switching time) seems not to depend on the temperature. (iv) Duration of the switching itself (movement of the Bloch point in the sample) increases from a few picoseconds at low temperatures to tens of picoseconds at high temperatures.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Study of high current commutation by explosive switch

    NASA Astrophysics Data System (ADS)

    Usuba, S.; Kakudate, Y.; Yoshida, M.; Fujiwara, S.; Miyamoto, M.; Morita, T.; Kubota, A.; den, M.

    1993-01-01

    The study presents the basic experimental data obtained with a large current opening switch for current commutation using explosives. It is shown that currents up to a maximum of 40 kA can be completely interrupted within 30 microsec. The mechanism of current interruption using a thin conductor plate and methods of measuring interrupting current with a pickup coil and taking photographs with a high-speed camera (one frame per microsec) are discussed.

  12. 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.

  13. Exploring new dielectrics to improve switching speeds of carbon nanotube memory devices

    NASA Astrophysics Data System (ADS)

    Lucas, Kristin Anne

    2011-12-01

    The hysteresis in carbon nanotube field effect transistor's (CNTFET) current vs. gate voltage curves can be used for memory devices. Testing possible changes to device structure and design, could improve both their endurance and switching speed characteristics. Preliminary work in the literature shows that the type of dielectric layer is a large factor in the device switching speed. Here, a new dielectric layer and a different device design will be tested to study how they affect the device performance. Results are compared to devices that are commercially available.

  14. A simple figure of merit for high temperature superconducting switches

    SciTech Connect

    Honig, E.M.

    1989-01-01

    The discovery of the new high temperature superconductors has revived interest in many special applications, including superconducting switches. For comparison of switch types, a simple figure of merit based in switch performance is proposed, derived for superconducting switches, and then calculated for thyristors and vacuum switches. The figure of merit is then used to show what critical current density would be needed for superconducting switches to compete with more conventional switches. 46 refs., 1 fig.

  15. A picosecond high pressure gas switch

    SciTech Connect

    Cravey, W.R.; Poulsen, P.P.; Pincosy, P.A.

    1992-06-01

    Work is being done to develop a high pressure gas switch (HPGS) with picosecond risetimes for UWB applications. Pulse risetimes on the order of 200 picoseconds have been observed at 1 kHz prf and 1 atmosphere. Calculations show that switching closure times on the order of tens of picoseconds can be achieved at high pressures and higher electric fields. A voltage hold-off of 1 MV/cm has been measured at 10 atmospheres and several MV/cm appears possible with the HPGS. With these high electric field levels, energy storage of tens of Joules in a reasonably sized package is achievable. Initial HPGS performance has been characterized on the WASP pulse generator at LLNL. A detailed description of the switch used for initial testing is given. Switch recovery times of 1-ms have been measured at 1 atmosphere. Data on the switching uniformity, voltage hold-off recovery, and pulse repeatability, is presented. In addition, a physics switch model is described and results are compared with lab data.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Pulse laser high speed schlieren photographic system and its application

    NASA Astrophysics Data System (ADS)

    Lin, Yuju; Li, Shicheng; Wang, Qingyou; Ni, Wenjun; Xiang, Yong

    1989-06-01

    Two models of a pulsed Q-switched ruby laser high speed schlieren photographic system are introduced. The models are described and results are presented from tests using each model. One model is used to record the armor-piercing process of the terminal trajectory and the chamber shooting process of the midway trajectory. The other model is used to study the detonating mechanism of high energy dynamite. Also, possibilities for future development of the system are considered.

  2. Compact high voltage solid state switch

    DOEpatents

    Glidden, Steven C.

    2003-09-23

    A compact, solid state, high voltage switch capable of high conduction current with a high rate of current risetime (high di/dt) that can be used to replace thyratrons in existing and new applications. The switch has multiple thyristors packaged in a single enclosure. Each thyristor has its own gate drive circuit that circuit obtains its energy from the energy that is being switched in the main circuit. The gate drives are triggered with a low voltage, low current pulse isolated by a small inexpensive transformer. The gate circuits can also be triggered with an optical signal, eliminating the trigger transformer altogether. This approach makes it easier to connect many thyristors in series to obtain the hold off voltages of greater than 80 kV.

  3. Liquid Nitrogen as Fast High Voltage Switching Medium

    NASA Astrophysics Data System (ADS)

    Dickens, J.; Neuber, A.; Haustein, M.; Krile, J.; Krompholz, H.

    2002-12-01

    Compact pulsed power systems require new switching technologies. For high voltages, liquid nitrogen seems to be a suitable switching medium, with high hold-off voltage, low dielectric constant, and no need for pressurized systems as in high pressure gas switches. The discharge behavior in liquid nitrogen, such as breakdown voltages, formative times, current rise as function of voltage, recovery, etc. are virtually unknown, however. The phenomenology of breakdown in liquid nitrogen is investigated with high speed (temporal resolution < 1 ns) electrical and optical diagnostics, in a coaxial system with 50-Ohm impedance. Discharge current and voltage are determined with transmission line type current sensors and capacitive voltage dividers. The discharge luminosity is measured with photomultiplier tubes. Preliminary results of self-breakdown investigations (gap 1 mm, breakdown voltage 44 kV, non-boiling supercooled nitrogen) show a fast (2 ns) transition from an unknown current level to several mA, a long-duration (100 ns) phase with constant current superimposed by ns-spikes, and a final fast transition to the impedance limited current during several nanoseconds. The optical measurements will be expanded toward spectroscopy and high speed photography with the aim of clarifying the overall breakdown mechanisms, including electronic initiation, bubble formation, bubble dynamics, and their role in breakdown, for different electrode geometries (different macroscopic field enhancements).

  4. 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.

  5. 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.

  6. A corona stabilized, high PRF closing switch

    SciTech Connect

    MacGregor, S.J.; Turnbull, S.M.; Tuema, F.A.

    1996-12-31

    This paper explains how the phenomenon of corona stabilization can be applied to high voltage, high PRF switching. A sealed corona stabilized spark gap has been operated at voltages of up to 50 kV, currents of up to 2 kA, and pulse repetition frequencies (PRFs) of up to 1 kHz and up to 5 kHz in burst mode. The effect of the corona is to stabilize the conditions in the switch at short times after breakdown and to create a suitable period for the reapplied voltage to reach the previous level before breakdown occurs. The switch therefore exhibits a much faster voltage recovery time compared to a more conventional uniform field spark gap and can therefore operate at high PRFs.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.'

  12. 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.

  13. 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.

  14. High-contrast and fast electrochromic switching enabled by plasmonics

    PubMed Central

    Xu, Ting; Walter, Erich C.; Agrawal, Amit; Bohn, Christopher; Velmurugan, Jeyavel; Zhu, Wenqi; Lezec, Henri J.; Talin, A. Alec

    2016-01-01

    With vibrant colours and simple, room-temperature processing methods, electrochromic polymers have attracted attention as active materials for flexible, low-power-consuming devices. However, slow switching speeds in devices realized to date, as well as the complexity of having to combine several distinct polymers to achieve a full-colour gamut, have limited electrochromic materials to niche applications. Here we achieve fast, high-contrast electrochromic switching by significantly enhancing the interaction of light—propagating as deep-subwavelength-confined surface plasmon polaritons through arrays of metallic nanoslits, with an electrochromic polymer—present as an ultra-thin coating on the slit sidewalls. The switchable configuration retains the short temporal charge-diffusion characteristics of thin electrochromic films, while maintaining the high optical contrast associated with thicker electrochromic coatings. We further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-colour response with high contrast and fast switching speeds, while relying on just one electrochromic polymer. PMID:26814453

  15. High-contrast and fast electrochromic switching enabled by plasmonics

    DOE PAGES

    Xu, Ting; Walter, Erich C.; Agrawal, Amit; ...

    2016-01-27

    With vibrant colours and simple, room-temperature processing methods, electrochromic polymers have attracted attention as active materials for flexible, low-power-consuming devices. However, slow switching speeds in devices realized to date, as well as the complexity of having to combine several distinct polymers to achieve a full-colour gamut, have limited electrochromic materials to niche applications. Here we achieve fast, high-contrast electrochromic switching by significantly enhancing the interaction of light—propagating as deep-subwavelength-confined surface plasmon polaritons through arrays of metallic nanoslits, with an electrochromic polymer—present as an ultra-thin coating on the slit sidewalls. The switchable configuration retains the short temporal charge-diffusion characteristics of thinmore » electrochromic films, while maintaining the high optical contrast associated with thicker electrochromic coatings. In conclusion, we further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-colour response with high contrast and fast switching speeds, while relying on just one electrochromic polymer.« less

  16. High-contrast and fast electrochromic switching enabled by plasmonics

    SciTech Connect

    Xu, Ting; Walter, Erich C.; Agrawal, Amit; Bohn, Christopher; Velmurugan, Jeyavel; Zhu, Wenqi; Lezec, Henri J.; Talin, A. Alec

    2016-01-27

    With vibrant colours and simple, room-temperature processing methods, electrochromic polymers have attracted attention as active materials for flexible, low-power-consuming devices. However, slow switching speeds in devices realized to date, as well as the complexity of having to combine several distinct polymers to achieve a full-colour gamut, have limited electrochromic materials to niche applications. Here we achieve fast, high-contrast electrochromic switching by significantly enhancing the interaction of light—propagating as deep-subwavelength-confined surface plasmon polaritons through arrays of metallic nanoslits, with an electrochromic polymer—present as an ultra-thin coating on the slit sidewalls. The switchable configuration retains the short temporal charge-diffusion characteristics of thin electrochromic films, while maintaining the high optical contrast associated with thicker electrochromic coatings. In conclusion, we further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-colour response with high contrast and fast switching speeds, while relying on just one electrochromic polymer.

  17. High-contrast and fast electrochromic switching enabled by plasmonics

    NASA Astrophysics Data System (ADS)

    Talin, Albert; Xu, Ting; Walter, Erich; Agrawal, Amit; Bohn, Christopher; Velmurugan, Jeyavel; Zhu, Wenqi; Lezec, Henri

    With vibrant colors and simple, room-temperature processing methods, electrochromic polymers have long attracted attention as active materials for flexible, low-power consuming devices such as smart windows and displays. However, despite their many advantages, slow switching speed and complexity of combining several separate polymers to achieve full-color gamut has limited electrochromic materials to niche applications. Here we exploit the enhanced light-matter interaction associated with the deep-subwavelength mode confinement of surface plasmon polaritons propagating in metallic nanoslit arrays coated with ultra-thin electrochromic polymers to build a novel configuration for achieving high-contrast and fast electrochromic switching. The switchable configuration retains the short temporal charge-diffusion characteristics of thin electrochromic films while maintaining the high optical-contrast associated with thicker electrochromic coatings. We further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-color response with high-contrast and fast switching-speeds while relying on just one electrochromic polymer.

  18. High-contrast and fast electrochromic switching enabled by plasmonics

    NASA Astrophysics Data System (ADS)

    Xu, Ting; Walter, Erich C.; Agrawal, Amit; Bohn, Christopher; Velmurugan, Jeyavel; Zhu, Wenqi; Lezec, Henri J.; Talin, A. Alec

    2016-01-01

    With vibrant colours and simple, room-temperature processing methods, electrochromic polymers have attracted attention as active materials for flexible, low-power-consuming devices. However, slow switching speeds in devices realized to date, as well as the complexity of having to combine several distinct polymers to achieve a full-colour gamut, have limited electrochromic materials to niche applications. Here we achieve fast, high-contrast electrochromic switching by significantly enhancing the interaction of light--propagating as deep-subwavelength-confined surface plasmon polaritons through arrays of metallic nanoslits, with an electrochromic polymer--present as an ultra-thin coating on the slit sidewalls. The switchable configuration retains the short temporal charge-diffusion characteristics of thin electrochromic films, while maintaining the high optical contrast associated with thicker electrochromic coatings. We further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-colour response with high contrast and fast switching speeds, while relying on just one electrochromic polymer.

  19. High-contrast and fast electrochromic switching enabled by plasmonics.

    PubMed

    Xu, Ting; Walter, Erich C; Agrawal, Amit; Bohn, Christopher; Velmurugan, Jeyavel; Zhu, Wenqi; Lezec, Henri J; Talin, A Alec

    2016-01-27

    With vibrant colours and simple, room-temperature processing methods, electrochromic polymers have attracted attention as active materials for flexible, low-power-consuming devices. However, slow switching speeds in devices realized to date, as well as the complexity of having to combine several distinct polymers to achieve a full-colour gamut, have limited electrochromic materials to niche applications. Here we achieve fast, high-contrast electrochromic switching by significantly enhancing the interaction of light--propagating as deep-subwavelength-confined surface plasmon polaritons through arrays of metallic nanoslits, with an electrochromic polymer--present as an ultra-thin coating on the slit sidewalls. The switchable configuration retains the short temporal charge-diffusion characteristics of thin electrochromic films, while maintaining the high optical contrast associated with thicker electrochromic coatings. We further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-colour response with high contrast and fast switching speeds, while relying on just one electrochromic polymer.

  20. 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.

  1. 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.

  2. Bidirectional all-optical switches based on highly nonlinear optical fibers

    NASA Astrophysics Data System (ADS)

    Liu, Wenjun; Yang, Chunyu; Liu, Mengli; Yu, Weitian; Zhang, Yujia; Lei, Ming; Wei, Zhiyi

    2017-05-01

    All-optical switches have become one of the research focuses of nonlinear optics due to their fast switching speed. They have been applied in such fields as ultrafast optics, all-optical communication and all-optical networks. In this paper, based on symbolic computation, bidirectional all-optical switches are presented using analytic two-soliton solutions. Various types of soliton interactions are analyzed through choosing the different parameters of high-order dispersion and nonlinearity. Results indicate that bidirectional all-optical switches can be effectively achieved using highly nonlinear optical fibers.

  3. Accelerated domain switching speed in single-crystal LiNbO{sub 3} thin films

    SciTech Connect

    Jiang, J.; Jiang, A. Q.; Meng, X. J.; Geng, D. Q.

    2015-03-14

    By using ionic implantation and wafer bonding technologies, we peeled off a single-crystal LiNbO{sub 3} thin film in the atomic-layer smoothness from the surface of a bulk Z-cut LiNbO{sub 3} single crystal. X-ray diffraction patterns showed only (00l) orientation of the film. From positive-up-negative–down pulse characterization, we measured domain switching current transients under various short-pulse voltages, where we observed domain switching currents to occur separately at time after initial capacitor charging currents. This is similar to early observations in bulk ferroelectric single crystals, where apparent positive/negative coercive fields of domain switching determined from polarization-electric field hysteresis loops always equal maximum/minimum applied fields. However, after pulse stressing of the film for more than 1000 cycles, the domain switching speed is accelerated, where domain switching current overlaps with the initial capacitor charging current with a well-defined coercive field independent of the applied-field strength. Finally, we simulated the whole domain switching current transients with the assumption of the resistance degradation across interfacial passive layers between the film and electrodes.

  4. 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.

  5. 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.

  6. 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.

  7. The generic enhancement of photochromic dye switching speeds in a rigid polymer matrix.

    PubMed

    Evans, Richard A; Hanley, Tracey L; Skidmore, Melissa A; Davis, Thomas P; Such, Georgina K; Yee, Lachlan H; Ball, Graham E; Lewis, David A

    2005-03-01

    The switching or isomerization speed of photochromic dyes in a rigid polymeric matrix (such as an ophthalmic lens) is generally significantly slower than that observed in the mobile environment of a solution. Here we describe that the attachment of flexible oligomers having a low glass-transition temperature-such as poly(dimethylsiloxane)-to photochromic dyes greatly increases their switching speeds in a rigid polymer matrix. The greatest impact was observed in the thermal fade parameters T(1/2) and T(3/4)-the times it takes for the optical density to reduce by half and three quarters of the initial optical density of the coloured state-which were reduced by 40-95% and 60-99% respectively for spirooxazines, chromenes and an azo dye in a host polymer with a glass-transition temperature of 120 degrees C. The method does not alter the electronic nature of the dyes but simply protects them from the host matrix and provides greater molecular mobility for the switching process. In addition to ophthalmic lenses, the generic nature of the method may find further utility in data recording or optical switching.

  8. 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.

  9. 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.

  10. 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.

  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 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)

  13. 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.

  14. Optically triggered high voltage switch network and method for switching a high voltage

    DOEpatents

    El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  15. An SFQ-based high-performance packet switch for next-generation high-end routers

    NASA Astrophysics Data System (ADS)

    Yorozu, S.; Kameda, Y.; Tahara, S.

    2001-08-01

    Switching throughput capacities of over 10 Tbps will be required of high-end systems on the backbones of nationwide telecommunications networks within the next decade. However conventional technologies cannot accommodate such capacities. Superconducting single flux quantum (SFQ) technology is a promising approach because of its ultra-low power consumption and ultra-high speed characteristics. We have proposed an opto-electronic-SFQ hybrid switching system. This system is separated into three functions: SFQ packet switching, high-performance CMOS control, and optical transmission. The packet switch is an improved Batcher-Banyan switch that uses a time-shifted internal speedup unit, and shuffle and grouping exchange schemes. Simulation showed good scalability; no conventional router could ever attain this capacity. We report on the numerical analysis and architectural-level design results for this packet switch.

  16. Redefining the Speed Limit of Phase Change Memory Revealed by Time-resolved Steep Threshold-Switching Dynamics of AgInSbTe Devices

    PubMed Central

    Shukla, Krishna Dayal; Saxena, Nishant; Durai, Suresh; Manivannan, Anbarasu

    2016-01-01

    Although phase-change memory (PCM) offers promising features for a ‘universal memory’ owing to high-speed and non-volatility, achieving fast electrical switching remains a key challenge. In this work, a correlation between the rate of applied voltage and the dynamics of threshold-switching is investigated at picosecond-timescale. A distinct characteristic feature of enabling a rapid threshold-switching at a critical voltage known as the threshold voltage as validated by an instantaneous response of steep current rise from an amorphous off to on state is achieved within 250 picoseconds and this is followed by a slower current rise leading to crystallization. Also, we demonstrate that the extraordinary nature of threshold-switching dynamics in AgInSbTe cells is independent to the rate of applied voltage unlike other chalcogenide-based phase change materials exhibiting the voltage dependent transient switching characteristics. Furthermore, numerical solutions of time-dependent conduction process validate the experimental results, which reveal the electronic nature of threshold-switching. These findings of steep threshold-switching of ‘sub-50 ps delay time’, opens up a new way for achieving high-speed non-volatile memory for mainstream computing. PMID:27886266

  17. Redefining the Speed Limit of Phase Change Memory Revealed by Time-resolved Steep Threshold-Switching Dynamics of AgInSbTe Devices

    NASA Astrophysics Data System (ADS)

    Shukla, Krishna Dayal; Saxena, Nishant; Durai, Suresh; Manivannan, Anbarasu

    2016-11-01

    Although phase-change memory (PCM) offers promising features for a ‘universal memory’ owing to high-speed and non-volatility, achieving fast electrical switching remains a key challenge. In this work, a correlation between the rate of applied voltage and the dynamics of threshold-switching is investigated at picosecond-timescale. A distinct characteristic feature of enabling a rapid threshold-switching at a critical voltage known as the threshold voltage as validated by an instantaneous response of steep current rise from an amorphous off to on state is achieved within 250 picoseconds and this is followed by a slower current rise leading to crystallization. Also, we demonstrate that the extraordinary nature of threshold-switching dynamics in AgInSbTe cells is independent to the rate of applied voltage unlike other chalcogenide-based phase change materials exhibiting the voltage dependent transient switching characteristics. Furthermore, numerical solutions of time-dependent conduction process validate the experimental results, which reveal the electronic nature of threshold-switching. These findings of steep threshold-switching of ‘sub-50 ps delay time’, opens up a new way for achieving high-speed non-volatile memory for mainstream computing.

  18. 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.

  19. 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.

  20. 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.

  1. Noise isolation system for high-speed circuits

    DOEpatents

    McNeilly, David R.

    1986-01-01

    A noise isolation circuit is provided that consists of a dual function bypass which confines high-speed switching noise to the component or circuit which generates it and isolates the component or circuit from high-frequency noise transients which may be present on the ground and power supply busses. A local circuit ground is provided which is coupled to the system ground by sufficient impedance to force the dissipation of the noise signal in the local circuit or component generating the noise. The dual function bypass network couples high-frequency noise signals generated in the local component or circuit through a capacitor to the local ground while isolating the component or circuit from noise signals which may be present on the power supply busses or system ground. The network is an effective noise isolating system and is applicable to both high-speed analog and digital circuits.

  2. Noise isolation system for high-speed circuits

    DOEpatents

    McNeilly, D.R.

    1983-12-29

    A noise isolation circuit is provided that consists of a dual function bypass which confines high-speed switching noise to the component or circuit which generates it and isolates the component or circuit from high-frequency noise transients which may be present on the ground and power supply busses. A local circuit ground is provided which is coupled to the system ground by sufficient impedance to force the dissipation of the noise signal in the local circuit or component generating the noise. The dual function bypass network couples high-frequency noise signals generated in the local component or circuit through a capacitor to the local ground while isolating the component or circuit from noise signals which may be present on the power supply busses or system ground. The network is an effective noise isolating system and is applicable to both high-speed analog and digital circuits.

  3. 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.

  4. Isolated Fast High-Voltage Switching Circuit

    NASA Technical Reports Server (NTRS)

    Rizzi, Anthony

    1992-01-01

    Electrically isolated switching circuit supplies pulses at potentials up to 6.5 kV and currents up to 6.5 A, lasting as long as few microseconds. Turn-on time about 40 ns; turn-off time about 3 microseconds. Electrically isolated from control circuitry by means of fiber-optic signal coupling and isolated power supply. Electrical isolation protects both technician and equipment. This and similar circuits useful in such industrial and scientific applications as high-voltage, high-frequency test equipment; electrostatic-discharge test equipment; plasma-laboratory instrumentation; spark chambers; and electromagnetic-interference test equipment.

  5. 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)

  6. 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.

  7. 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.

  8. Optoelectronic techniques for broadband switching

    NASA Astrophysics Data System (ADS)

    Su, S. F.; Jou, L.; Lenart, J.

    1988-01-01

    Optoelectronic switching employs a hybrid optical/electronic principle to perform the switching function and is applicable for either analog broadband or high-bit rate digital switching. The major advantages of optoelectronic switching include high isolation, low crosstalk, small physical size, light weight, and low power consumption. These advantages make optoelectronic switching an excellent candidate for on-board satellite switching. This paper describes a number of optoelectronic switching architectures. System components required for implementing these switching architectures are discussed. Performance of these architectures are evaluated by calculating their crosstalk, isolation, insertion loss, matrix size, drive power, throughput, and switching speed. Technologies needed for monolithic optoelectronic switching are also identified.

  9. Arc-Free High-Power dc Switch

    NASA Technical Reports Server (NTRS)

    Miller, W. N.; Gray, O. E.

    1982-01-01

    Hybrid switch allows high-power direct current to be turned on and off without arcing or erosion. Switch consists of bank of transistors in parallel with mechanical contacts. Transistor bank makes and breaks switched circuit; contacts carry current only during steady-state "on" condition. Designed for Space Shuttle orbiter, hybrid switch can be used also in high-power control circuits in aircraft, electric autos, industrial furnaces, and solar-cell arrays.

  10. Characterization of surface discharge switches and high performance applications

    SciTech Connect

    Reinovsky, R.E.; Goforth, J.H.; Greene, A.E.; Graham, J.

    1987-01-01

    Results of experiments which were conducted to characterize the performance of a surface discharge as a high-performance, self-closing isolation switch for high energy applications are described. These experiments, conducted under both dc and pulsed conditions, lead to a model of switch operation which enables the design of such switches for multi-megajoule operation. The paper describes the successful implementation of a surface switch as an operational component in a multi-megampere pulse-power system.

  11. 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

  12. 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.

  13. Improved Lifetime High Voltage Switch Electrode.

    DTIC Science & Technology

    2014-09-26

    and T.R. Burkes, "Erosion of Spark Gap Electrodes", IEEE Trans. Plasma Sci., PS-8, 149, (1980). 5. L.B. Gordon, M. Kristiansen, M.O. Hagler, H.C...Kirbie, R.M. Ness, L.L. Hatfield and 3.N. Marx, "Material Studies in a High Energy Spark Gap", IEEE Trans. Plasma Sci., PS-10, 286, (1982). 6. A.L...identify by block number) Spark switches, electrodes, ion implantation. _. / 20. ABSTRACT (Cqntnu* on ,.as maide Ii necossery and Identify by block number

  14. 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)

  15. A new very high voltage semiconductor switch

    NASA Technical Reports Server (NTRS)

    Sundberg, G. R.

    1985-01-01

    A new family of semiconductor switches using double injection techniques and compensated deep impurities is described. They have the potential to raise switching voltages a factor of 10 higher (up to 100 kV) than p-n junction devices while exhibiting extremely low (or zero) forward voltage. Several potential power switching applications are indicated.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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.

  1. Fast high-temperature superconductor switch for high current applications

    SciTech Connect

    Solovyov, VF; Li, Q

    2013-07-15

    Reversible operation of a high current superconductor switch based on the quench of high-resistance second generation high temperature superconducting wire is demonstrated. The quench is induced by a burst of an ac field generated by an inductively coupled radio-frequency coil. The switch makes a superconducting-to-normal transition within 5 ms and also has a rapid recovery to the superconducting state. The device has potential applications as an active current limiter or as a storage switch for superconducting magnetic energy storage systems. Operation in a full flux penetration/flow regime can effectively minimize the detrimental effects of the intrinsic conductor non-uniformity. (C) 2013 AIP Publishing LLC.

  2. Solid state switch provides high input-to-output isolation

    NASA Technical Reports Server (NTRS)

    Magee, R. L.; Trowbridge, L. E.

    1970-01-01

    Switch uses a combination of N-channel and P-channel Metal Oxide Semiconductor Field Effect Transistors /MOSFET/ to obtain a normally open switch with no power applied. Series-shunt-series MOSFET switching achieves high input-output isolation.

  3. Phase controlled dc-ac converter with high frequency switching

    NASA Astrophysics Data System (ADS)

    Harada, Koosuke; Sakamoto, Hiroshi; Shoyama, Masahito

    A sinusoidal dc-ac converter is presented in which a pair of switches is placed on each side of the primary and secondary of the isolation transformer. This converter is controlled by the phase difference between the two pairs of switches. The transformer is miniaturized by making the switching frequency high. This converter is especially suitable for small uninterruptible power supply systems.

  4. A cross-stacked plasmonic nanowire network for high-contrast femtosecond optical switching

    NASA Astrophysics Data System (ADS)

    Lin, Yuanhai; Zhang, Xinping; Fang, Xiaohui; Liang, Shuyan

    2016-01-01

    We report an ultrafast optical switching device constructed by stacking two layers of gold nanowires into a perpendicularly crossed network, which works at a speed faster than 280 fs with an on/off modulation depth of about 22.4%. The two stacks play different roles in enhancing consistently the optical switching performance due to their different dependence on the polarization of optical electric fields. The cross-plasmon resonance based on the interaction between the perpendicularly stacked gold nanowires and its Fano-coupling with Rayleigh anomaly is the dominant mechanism for such a high-contrast optical switching device.

  5. K-band high power latching switch

    NASA Astrophysics Data System (ADS)

    Mlinar, M. J.; Piotrowski, W. S.; Raue, J. E.

    1980-12-01

    A 19 GHz waveguide latching switch with a bandwidth of 1400 MHz and an exceptionally low insertion loss of 0.25 dB was demonstrated. The RF and driver ferrites are separate structures and can be optimized individually. This analysis for each structure is separately detailed. Basically, the RF section features a dual turnstile junction. The circulator consists of a dielectric tube which contains two ferrite rods, and a dielectric spacer separating the ferrite parts along the center of symmetry of the waveguide to form two turnstiles. This subassembly is indexed and locked in the center of symmetry of a uniform junction of three waveguides by the metallic transformers installed in the top and bottom walls of the housing. The switching junction and its actuating circuitry met all RF performance objectives and all shock and vibration requirements with no physical damage or performance degradation. It exceeds thermal requirements by operating over a 100 C temperature range (-44 C to +56 C) and has a high power handling capability allowing up to 100 W of CW input power.

  6. 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.

  7. 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.

  8. 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.

  9. In vitro assessment of fiber sweeping speed during Q-switched 532-nm laser tissue ablation

    NASA Astrophysics Data System (ADS)

    Rajabhandharaks, Danop; Kang, Hyun Wook; Ko, Woo Jin; Stinson, Douglas; Choi, Benjamin

    2011-03-01

    Photoselective vaporization of the prostate (PVP) is considered a minimally invasive procedure to treat benign prostatic hyperplasia (BPH). During the PVP, the prostate gland is irradiated by the 532-nm laser and the fiber is swept and dragged along the urethra. In this study the speed of sweeping fiber during the PVP is being investigated. In vitro porcine kidney model was used (N=100) throughout the experiment. A Q-switched 532-nm laser, equipped with sidefiring 750-Um fiber, was employed and set to power levels of 120 and 180 W. The speed of fiber sweeping was the only variable in this study and varied at 0 (i.e. no sweeping), 0.5, 1.0, 1.5, and 2.0 sweep/s. Ablation rate, depth, and coagulation thickness were quantified. Based on the current settings, ablation rate decreased as sweeping speed increased and was maximized between 0 to 1.0 sweep/s for 120-W power level and between 0 to 0.5 sweep/s for 180-W power level. Ablation rate at 180 W was higher than that at 120 W, regardless of sweeping speed. Ablation depth at both 120 and 180 W was maximized at 0 sweep/s and decreased 35% at 0.5 sweep/s. The overall coagulation thickness was less than 1.5 mm and comparable from 0 to 1.5 sweep/s (0.8~0.9 mm) and increased at 2.0 sweep/s (~1.1 mm). This study demonstrated that tissue ablation performance was contingent upon sweeping speed and maximized at slow sweeping speed due to longer laser-tissue interaction time and larger area coverage by the 532-nm light.

  10. 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.

  11. 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.

  12. A Double-Pole High Voltage High Current Switch

    DTIC Science & Technology

    2005-12-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited A DOUBLE- POLE HIGH...December 2005 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: A Double- Pole High Voltage High Current Switch 6. AUTHOR(S...to divert heavy charged particles, e.g. Cu+. 15. NUMBER OF PAGES 68 14. SUBJECT TERMS Double- Pole , Pulse Forming Inductive Network, PFIN

  13. 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.

  14. 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,…

  15. 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,…

  16. High-frequency switching in Candida albicans.

    PubMed Central

    Soll, D R

    1992-01-01

    Most strains of Candida albicans are capable of switching frequently and reversibly between a number of phenotypes distinguishable by colony morphology. A number of different switching systems have been defined according to the limited set of phenotypes in each switching repertoire, and each strain appears to possess a single system. Switching can affect many aspects of cellular physiology and morphology and appears to be a second level of phenotypic variability superimposed upon the bud-hypha transition. The most dramatic switching system so far identified is the "white-opaque transition." This system dramatizes the extraordinary effects switching can have on the budding cell phenotype, including the synthesis of opaque-specific antigens, the expression of white-specific and opaque-specific genes, and the genesis of unique cell wall structures. Switching has been demonstrated to occur at sites of infection and between episodes of recurrent vaginitis, and it may function to generate variability in commensal and infecting populations for adaptive reasons. Although the molecular mechanisms involved in the switch event are not understood, recent approaches to its elucidation are discussed and an epigenetic mechanism is proposed. Images PMID:1576587

  17. Highball: A high speed, reserved-access, wide area network

    NASA Technical Reports Server (NTRS)

    Mills, David L.; Boncelet, Charles G.; Elias, John G.; Schragger, Paul A.; Jackson, Alden W.

    1990-01-01

    A network architecture called Highball and a preliminary design for a prototype, wide-area data network designed to operate at speeds of 1 Gbps and beyond are described. It is intended for applications requiring high speed burst transmissions where some latency between requesting a transmission and granting the request can be anticipated and tolerated. Examples include real-time video and disk-disk transfers, national filestore access, remote sensing, and similar applications. The network nodes include an intelligent crossbar switch, but have no buffering capabilities; thus, data must be queued at the end nodes. There are no restrictions on the network topology, link speeds, or end-end protocols. The end system, nodes, and links can operate at any speed up to the limits imposed by the physical facilities. An overview of an initial design approach is presented and is intended as a benchmark upon which a detailed design can be developed. It describes the network architecture and proposed access protocols, as well as functional descriptions of the hardware and software components that could be used in a prototype implementation. It concludes with a discussion of additional issues to be resolved in continuing stages of this project.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Modelling and Analysis of High Pressure Peaking Switch

    NASA Astrophysics Data System (ADS)

    S, Bindu; Parekh, Mrunal; Mangalvedekar, H. A.; Sharma, Archana; Chakravarthy, D. P.

    2012-07-01

    This paper presents modelling and analysis of peaking switch used in Marx generator, such that the rise time of the pulse produced by the Marx generator is reduced substantially. Towards this FEMM (Finite Element Methods Magnetics) software is used for the field modelling of the switch and MATLAB for circuit modelling to observe the rise time. The switch has to produce pulse with sub-nanosecond rise time, hence the electrode distance has to be minimum. This switch can withstand high voltage only under high pressure. A mathematical model is simulated in MATLAB to see the performance under high pressure.

  13. 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.

  14. 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.

  15. A High Isolation Series-Shunt RF MEMS Switch

    PubMed Central

    Yu, Yuan-Wei; Zhu, Jian; Jia, Shi-Xing; Shi, Yi

    2009-01-01

    This paper presents a wide band compact high isolation microelectromechanical systems (MEMS) switch implemented on a coplanar waveguide (CPW) with three ohmic switch cells, which is based on the series-shunt switch design. The ohmic switch shows a low intrinsic loss of 0.1 dB and an isolation of 24.8 dB at 6 GHz. The measured average pull-in voltage is 28 V and switching time is 47 μs. In order to shorten design period of the high isolation switch, a structure-based small-signal model for the 3-port ohmic MEMS switch is developed and parameters are extracted from the measured results. Then a high isolation switch has been developed where each 3-port ohmic MEMS switch is closely located. The agreement of the measured and modeled radio frequency (RF) performance demonstrates the validity of the electrical equivalent model. Measurements of the series-shunt switch indicate an outstanding isolation of more than 40 dB and a low insertion loss of 0.35 dB from DC to 12 GHz with total chip size of 1 mm × 1.2 mm. PMID:22408535

  16. Switch on the high thermal conductivity of graphene paper.

    PubMed

    Xie, Yangsu; Yuan, Pengyu; Wang, Tianyu; Hashemi, Nastaran; Wang, Xinwei

    2016-10-14

    This work reports on the discovery of a high thermal conductivity (κ) switch-on phenomenon in high purity graphene paper (GP) when its temperature is reduced from room temperature down to 10 K. The κ after switch-on (1732 to 3013 W m(-1) K(-1)) is 4-8 times that before switch-on. The triggering temperature is 245-260 K. The switch-on behavior is attributed to the thermal expansion mismatch between pure graphene flakes and impurity-embedded flakes. This is confirmed by the switch behavior of the temperature coefficient of resistance. Before switch-on, the interactions between pure graphene flakes and surrounding impurity-embedded flakes efficiently suppress phonon transport in GP. After switch-on, the structure separation frees the pure graphene flakes from the impurity-embedded neighbors, leading to a several-fold κ increase. The measured κ before and after switch-on is consistent with the literature reported κ values of supported and suspended graphene. By conducting comparison studies with pyrolytic graphite, graphene oxide paper and partly reduced graphene paper, the whole physical picture is illustrated clearly. The thermal expansion induced switch-on is feasible only for high purity GP materials. This finding points out a novel way to switch on/off the thermal conductivity of graphene paper based on substrate-phonon scattering.

  17. Characteristics of current filamentation in high gain photoconductive semiconductor switching

    SciTech Connect

    Zutavern, F J; Loubriel, G M; O'Malley, M W; Helgeson, W D; McLaughlin, D L; Denison, G J

    1992-01-01

    Characteristics of current filamentation are reported for high gain photoconductive semiconductor switches (PCSS). Infrared photoluminescence is used to monitor carrier recombination radiation during fast initiation of high gain switching in large (1.5 cm gap) lateral GaAs PCSS. Spatial modulation of the optical trigger, a 200--300 ps pulse width laser, is examined. Effects on the location and number of current filaments, rise time, and delay to high gain switching, minimum trigger energy, and degradation of switch contacts are presented. Implications of these measurements for the theoretical understanding and practical development of these switches are discussed. Efforts to increase current density and reduce switch size and optical trigger energy requirements are described. Results from contact development and device lifetime testing are presented and the impact of these results on practical device applications is discussed.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, Rodney J.

    1996-01-01

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources.

  6. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, R.J.

    1996-10-22

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode is disclosed. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources. 12 figs.

  7. High voltage switches having one or more floating conductor layers

    SciTech Connect

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  8. 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.

  9. 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.

  10. Low-Cost High-Speed Techniques for Real-Time Simulation of Power Electronic Systems

    DTIC Science & Technology

    2007-06-01

    simulations. The other parts of the math model (switching logic, PWM control functions) are more readily converted into FPGA functions. Some progress has...7 3.3 High-Speed Real-Time Simulation with the FPGA ..................... 8 4.0 STABILITY ANALYSIS...increasing use of higher- frequency, pulse-width modulation ( PWM ) controllers a need arose for higher-speed, but lower cost, real-time simulators. This

  11. Hunting for eclipses: high-speed observations of cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Hardy, L. K.; McAllister, M. J.; Dhillon, V. S.; Littlefair, S. P.; Bours, M. C. P.; Breedt, E.; Butterley, T.; Chakpor, A.; Irawati, P.; Kerry, P.; Marsh, T. R.; Parsons, S. G.; Savoury, C. D. J.; Wilson, R. W.; Woudt, P. A.

    2017-03-01

    We present new time-resolved photometry of 74 cataclysmic variables (CVs), 47 of which are eclipsing. Thirteen of these eclipsing systems are newly discovered. For all 47 eclipsing systems, we show high cadence (1-20 s) light curves obtained with the high-speed cameras ULTRACAM and ULTRASPEC. We provide new or refined ephemerides, and supply mid-eclipse times for all observed eclipses. We assess the potential for light-curve modelling of all 47 eclipsing systems to determine their system parameters, finding 20 systems that appear to be suitable for future study. Systems of particular interest include V713 Cep, in which we observed a temporary switching-off of accretion; and ASASSN-14mv and CSS111019:233313-155744, which both have orbital periods well below the CV period minimum. The short orbital periods and light-curve shapes suggest that they may be double degenerate (AM CVn) systems or CVs with evolved donor stars.

  12. 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.

  13. 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).

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. 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.

  3. 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.

  4. REDUCTION OF EMISSIONS FROM A HIGH SPEED FERRY

    SciTech Connect

    Thompson,G.; Gautam, M; Clark, N; Lyons, D; Carder, D; Riddle, W; Barnett, R; Rapp, B; George, S

    2003-08-24

    Emissions from marine vessels are being scrutinized as a major contributor to the total particulate matter (TPM), oxides of sulfur (SOx) and oxides of nitrogen (NOx) environmental loading. Fuel sulfur control is the key to SOx reduction. Significant reductions in the emissions from on-road vehicles have been achieved in the last decade and the emissions from these vehicles will be reduced by another order of magnitude in the next five years: these improvements have served to emphasize the need to reduce emissions from other mobile sources, including off road equipment, locomotives, and marine vessels. Diesel-powered vessels of interest include ocean going vessels with low- and medium-speed engines, as well as ferries with high speed engines, as discussed below. A recent study examined the use of intake water injection (WIS) and ultra low sulfur diesel (ULSD) to reduce the emissions from a high-speed passenger ferry in southern California. One of the four Detroit Diesel 12V92 two-stroke high speed engines that power the Waverider (operated by SCX, inc.) was instrumented to collect intake airflow, fuel flow, shaft torque, and shaft speed. Engine speed and shaft torque were uniquely linked for given vessel draft and prevailing wind and sea conditions. A raw exhaust gas sampling system was utilized to measure the concentration of NOx, carbon dioxide (CO2), and oxygen (O2) and a mini dilution tunnel sampling a slipstream from the raw exhaust was used to collect TPM on 70 mm filters. The emissions data were processed to yield brake-specific mass results. The system that was employed allowed for redundant data to be collected for quality assurance and quality control. To acquire the data, the Waverider was operated at five different steady state speeds. Three modes were in the open sea off Oceanside, CA, and idle and harbor modes were also used. Data have showed that the use of ULSD along with water injection (WIS) could significantly reduce the emissions of NOx and PM

  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. Triggered vacuum flashover switch for high-power applications

    SciTech Connect

    Kellogg, J.C.; Boller, J.R.; Commisso, R.J.; Jenkins, D.J. ); Ford, R.D. ); Lupton, W.H. ); Shipman, J.D. Jr. )

    1991-11-01

    A command triggered, high-power, surface-flashover closing switch that operates in vacuum has been developed for use on a prototype inductive-storage pulsed power generator, Pawn. This vacuum flashover switch isolates the high-pressure-gas tamped wire fuse from a second opening switch. The switch consists of an insulating ring sandwiched between electrodes. Plasma and ultraviolet light from eight small spark discharges driven by a 5 keV pulse initiate a flashover across the switch insulator. The entire triggering unit resides inside one of Pawn's metallic conductors. The switch can be triggered after holding off voltage for {congruent}15 {mu}s. Normally, switch closure occurs at 22--45 kV. Time to closure at a voltage of {congruent}30 kV is {congruent}320 ns, with a typical jitter of {plus minus}50 ns. Peak current is typically {congruent}1 MA. Current density in the switch is approximately 25 kA/cm{sup 2}. The average risetime of the fuse output current pulse can be varied by a factor of 2 by triggering the switch at different closing voltages.

  8. High on/off capacitance ratio RF MEMS capacitive switches

    NASA Astrophysics Data System (ADS)

    Wei, Hao; Deng, Zhongliang; Guo, Xubing; Wang, Yucheng; Yang, Hongtao

    2017-05-01

    In this paper, high on/off capacitance ratio radio frequency micro-electro-mechanical-systems (RF MEMS) switches are designed, fabricated, measured and analyzed. Two types of RF MEMS switches, a shunt switch with a contact point and an inline switch without a contact point, are presented. Metal-insulator-metal (MIM) fixed capacitors are used in the MEMS switches. The electrode topologies of RF MEMS switches are analyzed. The parameter λ is defined to describe the relationship between the capacitance ratio, the height of the beam and the actuation voltage. The measured results indicate that, for MEMS switch #1 with a contact point and gap of 1 µm, the insertion loss is better than 0.64 dB up to 40 GHz, and the isolation is more than 20 dB from 11.28 to 30.38 GHz with an actuation voltage of 42 V. For the inline MEMS with a displacement of 1.5 µm, the insertion loss is better than 0.56 dB up to 40 GHz, and the isolation is more than 20 dB from 4.45 to 30.48 GHz with an actuation voltage of 36 V. Circuit models and measured results of the proposed MEMS switches show good agreement. From the fitted results, the on/off capacitance ratio is ~227 for the MEMS switch #1 and ~313 for the MEMS switch #2, respectively. Compared with traditional MEMS capacitive switches with dielectric material Si3N4 and a relatively lower gap (1.5 µm), the proposed MEMS switches exhibit high on/off capacitance ratios.

  9. Computer modeling of plasma flow switches-high current switching on Procyon

    SciTech Connect

    Bowers, R.L.; Greene, A.E.; Peterson, D.L.; Roderick, N.F.

    1993-09-01

    Procyon is a high explosive driven pulsed power system designed to drive plasma z-pinch experiments to the 1-MJ level. Details of this system are provided elsewhere in these proceedings. The final switching stage of the Procyon system is a plasma flow switch (PFS). Our most recent experiment (April 29, 1993) included a full power test of the PFS designed for the Procyon system. In this test the Mark IX explosively driven generator delivered 22 MA of current to the storage inductor. The slight flux compression that occurs in the explosively formed fuse (EFF) opening switch increased this current to 24.5 MA. The EFF then opened and switched 16.5 MA to the PFS. The PFS switched 15.5 MA to the load region (the slot that will contain an imploding foil liner in future experiments) with a 10-90 rise time of 500 ns. In this present paper we discuss the computer modeling we have done on this Procyon plasma flow switch. In the next section we discuss the design of the Procyon switch and preshot calculations. Although the April 1993 experiment was quite successful there were significant surprizes in the performance of the PFS. In the last sections of this paper we discuss the work we have done in understanding the results of this experiment and the conclusions that we have reached to date.

  10. High Voltage Switch Using Externally Ionized Plasmas.

    DTIC Science & Technology

    1980-04-01

    circuit breakers were not considered because their re- sponse is too slow to meet the on/off and PRF requirements. These constraints narrowed the number of...ELECTRON-BEAM PLASMA SWITCH STUDY 4 2.1 Model Description 4 2.1.1 Plasma and Circuit Models 4 2.1.2 Electron Beam Source Model 8 2.2 Gas Selection...70 "usttloatIon ~in Diutribut 0. is Avail and/or sit pecial 4/ LIST OF ILLUSTRATIONS FIGURE PAGE 1. Circuit Assumed in the Switch Computer Program 6

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Optically initiated silicon carbide high voltage switch

    SciTech Connect

    Caporaso, George J; Sampayan, Stephen E; Sullivan, James S; Sanders,; David, M

    2011-02-22

    An improved photoconductive switch having a SiC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.

  18. 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.

  19. Pulse Laser High Speed Schlieren Photographic System And Its Application

    NASA Astrophysics Data System (ADS)

    Yuju, Lin; Shicheng, Li; Qingyou, Wang; Wenjun, Ni; Yong, Xiang; Jingliang, Shi

    1989-06-01

    The sequential pulsed, Q-switched ruby laser is used for the light source. Liodel 640 schilieren apparatus is used for the display optical system of image and flow field. The access type rotating mirror scanning high speed camera is used for recording unit. They are assembled into a complete set of Pulsed Laser High Speed Schlieren Photographic System. So far, we have designed and trial-manufactured two types. The Model I system is used for recording the armor-piercing process of the terminal trajectory and the chamber-shooting process of the midway trajectory. The better results have been obtained. The Eodel II system is used for studying the detonating mechanism of high energy dynamite. The framing pictures of the bullet flying attitude before bullet collides the target and the compressive deformation after it collides the target as well as the detonating process have been taken. These photos have provided the basis for research work. The future development of the system has also been discussed in this paper.

  20. Photoconductive switching for HPM (high power microwave) generation

    SciTech Connect

    Pocha, M.D.; Hofer, W.W.

    1990-01-01

    Photoconductive switching has been explored at LLNL and demonstrated to be a viable technology for high power microwave (HPM) generation. This technology enables the development of compact, portable, and efficient HPM sources. At LLNL we have successfully switched 35 KV in <200 ps using laser triggered, 1 {times} 5 {times} 20 mm GaAs switches. Based on these results we are developing an HPM generator with applications for HPM weapons and high power, wideband radar. The paper will discuss the physics limits and tradeoffs in the application of this technology. Among the topics discussed will be switching efficiency, candidate switch materials, laser requirements, applicable laser technologies, generator configurations, and cooling requirements and techniques. In addition to presenting theoretical and practical considerations, the paper will discuss on-going work at LLNL and elsewhere. 11 refs., 2 figs., 1 tab.

  1. High Power Microwave Switch Employing Electron Beam Triggering

    NASA Astrophysics Data System (ADS)

    Ivanov, O. A.; Isaev, V. A.; Lobaev, M. A.; Vikharev, A. L.; Hirshfield, J. L.

    2010-11-01

    A new type of switch for modulation of the Q-factor of a multi-mode storage resonator in a high-power active microwave pulse compressor is described. The operating principle of the switch is based on a sharp increase in the TE02→TE01 coupling coefficient, when an electron beam is injected into the switch cavity. The switch was tested at low power level in a compressor operated at X-band. A power gain of 19-20 in the compressed pulse with pulse duration of 40-50 ns was achieved. The proposed switch shows good prospects for use in high-power active pulse compressors.

  2. Photoconductive switching for HPM (High Power Microwave) generation

    NASA Astrophysics Data System (ADS)

    Pocha, M. D.; Hofer, W. W.

    Photoconductive switching has been explored at LLNL and demonstrated to be a viable technology for high power microwave (HPM) generation. This technology enables the development of compact, portable, and efficient HPM sources. At LLNL we have successfully switched 35 KV in less than 200 ps using laser triggered, 1 x 5 x 20 mm GaAs switches. Based on these results we are developing an HPM generator with applications for HPM weapons and high power, wideband radar. The paper will discuss the physics limits and tradeoffs in the application of this technology. Among the topics discussed will be switching efficiency, candidate switch materials, laser requirements, applicable laser technologies, generator configurations, and cooling requirements and techniques. In addition to presenting theoretical and practical considerations, the paper will discuss on-going work at LLNL and elsewhere.

  3. 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.

  4. 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.

  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. 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.

  17. 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.

  18. High-power microstrip RF switch

    NASA Technical Reports Server (NTRS)

    Choi, S. D.

    1971-01-01

    A microstrip-type single-pole double-throw (SPDT) switch whose RF and bias portions contain only a metallized alumina substrate and two PIN diodes has been developed. A technique developed to eliminate the dc blocking capacitors needed for biasing the diodes is described. These capacitors are extra components and could lower the reliability significantly. An SPDT switch fabricated on a 5.08 x 5.08 x 0.127-cm (2 x 2 x 0.050-in.) substrate has demonstrated an RF power-handling capability greater than 50 W at S-band. The insertion loss is less than 0.25 db and the input-to-off port isolation is greater than 36 db over a bandwidth larger than 30 MHz. The input voltage standing-wave ratio is lower than 1.07 over the same bandwidth. Theoretical development of the switch characteristics and experimental results, which are in good agreement with theory, are presented.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. Subnanosecond, high voltage photoconductive switching in GaAs

    SciTech Connect

    Druce, R.L.; Pocha, M.D.; Griffin, K.L. ); O'Bannon, B.J. )

    1990-01-01

    We are conducting research on the switching properties of photoconductive materials to explore their potential for generating high-power microwaves (HPM) and for high rep-rate switching. We have investigated the performance of Gallium Arsenide (GaAs) in linear mode (the conductivity of the device follows the optical pulse) as well as an avalanche-like mode (the optical pulse only controls switch closing). Operating in the linear mode, we have observed switch closing times of less than 200 ps with a 100 ps duration laser pulse and opening times of less than 400 ps at several kV/cm fields using neutron irradiated GaAs. In avalanche and lock-on modes, high fields are switched with lower laser pulse energies, resulting in higher efficiencies; but with measurable switching delay and jitter. We are currently investigating both large area (1 cm{sup 2}) and small area (<1 mm{sup 2}) switches illuminated by AlGaAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 {mu}m.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. High accuracy switched-current circuits using an improved dynamic mirror

    NASA Technical Reports Server (NTRS)

    Zweigle, G.; Fiez, T.

    1991-01-01

    The switched-current technique, a recently developed circuit approach to analog signal processing, has emerged as an alternative/compliment to the well established switched-capacitor circuit technique. High speed switched-current circuits offer potential cost and power savings over slower switched-capacitor circuits. Accuracy improvements are a primary concern at this stage in the development of the switched-current technique. Use of the dynamic current mirror has produced circuits that are insensitive to transistor matching errors. The dynamic current mirror has been limited by other sources of error including clock-feedthrough and voltage transient errors. In this paper we present an improved switched-current building block using the dynamic current mirror. Utilizing current feedback the errors due to current imbalance in the dynamic current mirror are reduced. Simulations indicate that this feedback can reduce total harmonic distortion by as much as 9 dB. Additionally, we have developed a clock-feedthrough reduction scheme for which simulations reveal a potential 10 dB total harmonic distortion improvement. The clock-feedthrough reduction scheme also significantly reduces offset errors and allows for cancellation with a constant current source. Experimental results confirm the simulated improvements.

  14. 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…

  15. 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…

  16. 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

  17. High-Temperature Switched-Reluctance Electric Motor

    NASA Technical Reports Server (NTRS)

    Montague, Gerald; Brown, Gerald; Morrison, Carlos; Provenza, Andy; Kascak, Albert; Palazzolo, Alan

    2003-01-01

    An eight-pole radial magnetic bearing has been modified into a switched-reluctance electric motor capable of operating at a speed as high as 8,000 rpm at a temperature as high as 1,000 F (=540 C). The motor (see figure) is an experimental prototype of starter-motor/generator units that have been proposed to be incorporated into advanced gas turbine engines and that could operate without need for lubrication or active cooling. The unique features of this motor are its electromagnet coils and, to some extent, its control software. Heretofore, there has been no commercial-off-the-shelf wire capable of satisfying all of the requirements for fabrication of electromagnet coils capable of operation at temperatures up to 1,000 F (=540 C). The issues addressed in the development of these electromagnet coils included thermal expansion, oxidation, pliability to small bend radii, micro-fretting, dielectric breakdown, tensile strength, potting compound, thermal conduction, and packing factor. For a test, the motor was supported, along with a rotor of 18 lb (.8-kg) mass, 3-in. (.7.6-cm) diameter, 21-in. (.53-cm) length, on bearings packed with high-temperature grease. The motor was located at the mid span of the rotor and wrapped with heaters. The motor stator was instrumented with thermocouples. At the time of reporting the information for this article, the motor had undergone 14 thermal cycles between room temperature and 1,000 F (.540 C) and had accumulated operating time >27.5 hours at 1,000 F (=540 C). The motor-controller hardware includes a personal computer equipped with analog-to-digital input and digital-to-analog output cards. The controller software is a C-language code that implements a switched-reluctance motor-control principle: that is, it causes the coils to be energized in a sequence timed to generate a rotating magnetic flux that creates a torque on a scalloped rotor. The controller can operate in an open- or closed-loop mode. In addition, the software has

  18. Fano resonance based ultra high-contrast electromagnetic switch

    NASA Astrophysics Data System (ADS)

    Amin, Muhammad; Ramzan, Rashad; Siddiqui, Omar

    2017-05-01

    We experimentally achieve highly asymmetrical enhanced-Q Fano resonances in metallic electromagnetic structures fabricated on conductive planes. We show that the complete destructive interference mechanism of the dark and bright resonant modes generated by a pair of electromagnetically coupled open-ended conductive arms can lead to the asymmetric resonance characterized by a near-unity transparency window followed by a deep scattering band. With the incorporation of a variable capacitor between the coupled metallic strips, the dynamic tunability of the resonant modes is achieved, which can be exploited in high isolation switches and modulators in the GHz spectrum. The switching contrast of over 50 dB achieved through Fano resonance is much higher considering its compact size (i.e., the transmission path is much smaller than the wavelength λ / 30 ). The dispersion based tunable Fano switch offers several advantages over conventional microelectromechanical system and CMOS based switches.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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.

  8. 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.

  9. 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.

  10. A microprocessor based high speed packet switch for satellite communications

    NASA Technical Reports Server (NTRS)

    Arozullah, M.; Crist, S. C.

    1980-01-01

    The architectures of a single processor, a three processor, and a multiple processor system are described. The hardware circuits, and software routines required for implementing the three and multiple processor designs are presented. A bit-slice microprocessor was designed and microprogrammed. Maximum throughput was calculated for all three designs. Queue theoretic models for these three designs were developed and utilized to obtain analytical expressions for the average waiting times, overall average response times and average queue sizes. From these expressions, graphs were obtained showing the effect on the system performance of a number of design parameters.

  11. Superconducting ''transistor'' acts as high-speed switch

    NASA Technical Reports Server (NTRS)

    Meissner, H.

    1970-01-01

    Cryogenic, three-terminal device yields current-voltage characteristics of ordinary transistor. Device consists of two superconducting tin rods in a crossed-wire geometry, separated by a thin gold film. New construction technique is described and possible applications are discussed.

  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. 6H Silicon Carbide Photoconductive Switches for High Power Applications

    DTIC Science & Technology

    2006-11-01

    6H SILICON CARBIDE PHOTOCONDUCTIVE SWITCHES FOR HIGH POWER APPLICATIONS W. C. Nunnally*, N. Islam, K. Kelkar & C. Fessler Photonics for Radars...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Photonics for Radars and Optical Systems...switches. Additional work by the UMC Photonics for Radar and Optical Systems (PROS) group has demonstrated that the relatively new material of

  18. High voltage photo switch package module

    SciTech Connect

    Sullivan, James S; Sanders, David M; Hawkins, Steven A; Sampayan, Stephen E

    2014-02-18

    A photo-conductive switch package module having a photo-conductive substrate or wafer with opposing electrode-interface surfaces, and at least one light-input surface. First metallic layers are formed on the electrode-interface surfaces, and one or more optical waveguides having input and output ends are bonded to the substrate so that the output end of each waveguide is bonded to a corresponding one of the light-input surfaces of the photo-conductive substrate. This forms a waveguide-substrate interface for coupling light into the photo-conductive wafer. A dielectric material such as epoxy is then used to encapsulate the photo-conductive substrate and optical waveguide so that only the metallic layers and the input end of the optical waveguide are exposed. Second metallic layers are then formed on the first metallic layers so that the waveguide-substrate interface is positioned under the second metallic layers.

  19. 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

  20. Switching LPV Control for High Performance Tactical Aircraft

    NASA Technical Reports Server (NTRS)

    Lu, Bei; Wu, Fen; Kim, SungWan

    2004-01-01

    This paper examines a switching Linear Parameter-Varying (LPV) control approach to determine if it is practical to use for flight control designs within a wide angle of attack region. The approach is based on multiple parameter-dependent Lyapunov functions. The full parameter space is partitioned into overlapping subspaces and a family of LPV controllers are designed, each suitable for a specific parameter subspace. The hysteresis switching logic is used to accomplish the transition among different parameter subspaces. The proposed switching LPV control scheme is applied to an F-16 aircraft model with different actuator dynamics in low and high angle of attack regions. The nonlinear simulation results show that the aircraft performs well when switching among different angle of attack regions.

  1. High-voltage, low-inductance gas switch

    DOEpatents

    Gruner, Frederick R.; Stygar, William A.

    2016-03-22

    A low-inductance, air-insulated gas switch uses a de-enhanced annular trigger ring disposed between two opposing high voltage electrodes. The switch is DC chargeable to 200 kilovolts or more, triggerable, has low jitter (5 ns or less), has pre-fire and no-fire rates of no more than one in 10,000 shots, and has a lifetime of greater than 100,000 shots. Importantly, the switch also has a low inductance (less than 60 nH) and the ability to conduct currents with less than 100 ns rise times. The switch can be used with linear transformer drives or other pulsed-power systems.

  2. 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.

  3. High voltage switch triggered by a laser-photocathode subsystem

    SciTech Connect

    Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

    2013-01-08

    A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

  4. High-voltage, high-current, solid-state closing switch

    DOEpatents

    Focia, Ronald Jeffrey

    2017-08-22

    A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. High-speed wavelength tunable DPSK demodulation using a phase modulator based loop mirror filter.

    PubMed

    Ge, Jia; Feng, Hanlin; Fok, Mable P

    2014-06-15

    A high-speed wavelength tunable differential phase-shift-keying (DPSK) signal demodulator is presented using a phase modulator (PM) based fiber loop mirror filter. By controlling the birefringence of the PM inside the loop through electro-optic effect, wavelength tuning speed of tens of GHz and tuning range of over two free spectral ranges are achieved. Stable filter spectra with extinction ratio over 30 dB are obtained through the tuning process. By combining the birefringence of polarization maintaining fiber and PM, error-free demodulation performance is experimentally achieved throughout the wavelength tuning range for DPSK signals with flexible bit-rate range from 2.5 to 10  Gb/s. This design significantly improves the wavelength tuning speed and is potentially valuable for high-speed switching and tuning applications.

  10. High Speed Imaging using Nanoprobe Arrays

    DTIC Science & Technology

    2010-06-23

    6774 2006. 13 B. Gotsmann, U. Dürig, J. Frommer , and C. J. Hawker, Adv. Funct. Mater. 16, 1499 2006. 14 S. Bakbak, P. J. Leech, B. E. Carson, S...2006. [36] B. Gotsmann, U. Dürig, J. Frommer , and C. J. Hawker, “Exploiting chemical switching in a Diels-Alder polymer for nanoscale probe litho

  11. Purely electronic switching with high uniformity, resistance tunability, and good retention in Pt-dispersed SiO2 thin films for ReRAM.

    PubMed

    Choi, Byung Joon; Chen, Albert B K; Yang, Xiang; Chen, I-Wei

    2011-09-01

    Resistance switching memory operating by a purely electronic switching mechanism, which was first realized in Pt-dispersed SiO2 thin films, satisfies criteria including high uniformity, fast switching speed, and long retention for non-volatile memory application. This resistive element obeys Ohm's law for the area dependence, but its resistance exponentially increases with the film thickness, which provides new freedom to tailor the device characteristics.

  12. Gate Drive For High Speed, High Power IGBTs

    SciTech Connect

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; /SLAC

    2007-06-18

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3{micro}S with a rate of current rise of more than 10000A/{micro}S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt.

  13. 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.

  14. 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.

  15. 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.

  16. Age differences in switching the relevant stimulus dimensions in a speeded same-different judgment paradigm.

    PubMed

    Hsieh, Shulan; Wu, Mengyao

    2010-10-01

    The present study employed a same-different judgment task-switching paradigm to re-examine the effects of age on switch costs. We manipulated perceptual and conceptual dimensions to serve as the criteria for making a same-different judgment. We also manipulated a short versus long cue-stimulus interval, while keeping the response-stimulus interval constant in order to examine whether older adults can benefit from longer preparatory intervals. The results indicate that older adults exhibited larger switch costs. In contrast to this impairment, older adults maintained the ability to prepare for an upcoming task switch. Nevertheless, even with a long preparatory interval, older adults still exhibited larger switch costs than younger adults. A more detailed analysis using a mixture model technique suggests that older adults' elevated residual costs in performing perceptual-judgment switches might be attributable to an increased probabilistic failure to complete advance preparation, whereas older adults' elevated residual costs in performing conceptual-judgment switches might be attributable to an intrinsic limitation in their ability to attain a complete task-set reconfiguration during a preparatory interval. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Optical vortex beam based optical fan for high-precision optical measurements and optical switching.

    PubMed

    Zhou, Zhi-Yuan; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Shi, Bao-Sen

    2014-09-01

    The polarization and orbital angular momentum properties of light are of great importance in optical science and technology in the fields of high-precision optical measurements and high-capacity and high-speed optical communications. Here we show a method for the construction of a simple and robust scheme to rotate a light beam such as a fan, which is based on a combination of these two properties and using the thermal-dispersion and electro-optical effect of birefringent crystals. Using a computer-based digital image-processing technique, we determine the temperature and thermal-dispersion difference of the crystal with high resolution. We also use the rotation phenomenon to realize thermo-optic and electro-optic switches. The basic operating principles for measurement and switching processes are presented in detail. The methods developed here will have wide practical applicability in various fields, including remote sensing, materials science, and optical communication networks.

  18. 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.

  19. 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.

  20. High-speed optimal steering of a tractor-semitrailer

    NASA Astrophysics Data System (ADS)

    Cheng, Caizhen; Roebuck, Richard; Odhams, Andrew; Cebon, David

    2011-04-01

    A high-speed optimal trailer steering controller for a tractor-semitrailer is discussed. A linear model of a tractor-semitrailer with steered trailer axles is described, and an optimal trailer steering controller is introduced. A path-following controller is derived to minimise the path-tracking error in steady-state manoeuvres using active trailer steering. A roll stability controller is introduced by adding the lateral acceleration of trailer centre of gravity as another objective in the steering controller, so as to improve roll stability in transient manoeuvres. A strategy to switch between these two control modes is demonstrated. Simulation results show that the steering controller can ensure good path tracking of articulated vehicles in steady-state manoeuvres and improve roll stability significantly in transient manoeuvres, while maintaining the path-tracking deviation within an acceptable range. Tests with an experimental tractor-semitrailer equipped with a high-bandwidth active steering system validate the controller design and simulation results. The roll stability controller reduces the measured rearward amplification by 27%.

  1. New Drive Train Concept with Multiple High Speed Generator

    NASA Astrophysics Data System (ADS)

    Barenhorst, F.; Serowy, S.; Andrei, C.; Schelenz, R.; Jacobs, G.; Hameyer, K.

    2016-09-01

    In the research project RapidWind (financed by the German Federal Ministry for Economic Affairs and Energy under Grant 0325642) an alternative 6 MW drive train configuration with six high-speed (n = 5000 rpm) permanent magnet synchronous generators for wind turbine generators (WTG) is designed. The gearbox for this drive train concept is assembled with a six fold power split spur gear stage in the first stage, followed by six individual 1 MW geared driven generators. Switchable couplings are developed to connect and disconnect individual geared generators depending on the input power. With this drive train configuration it is possible to improve the efficiency during partial load operation, increasing the energy yield about 1.15% for an exemplary low-wind site. The focus of this paper is the investigation of the dynamic behavior of this new WTG concept. Due to the high gear ratio the inertia relationship between rotor and generator differs from conventional WT concepts, possibly leading to intensified vibration behavior. Moreover there are switching procedures added, that might also lead to vibration issues.

  2. 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.

  3. 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.

  4. 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.

  5. 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.'

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Development of high speed power thyristor: The gate assisted turn-off thyristor

    NASA Technical Reports Server (NTRS)

    Hamilton, D. R.; Brewster, J.; Frobenius, D.; Desmond, T.

    1972-01-01

    A high speed power switch with unique turn-off capability was developed. This gate-assisted turn-off thyristor was rated at 609 V and 50 A with turn-off times of 2 microsec. Twenty-two units were delivered for evaluation in a series inverter circuit. In addition, test circuits designed to relate to the series inverter application were built and demonstrated.

  14. 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.

  15. 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

  16. 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.

  17. Scalable, high-capacity optical switches for Internet routers and moving platforms

    NASA Astrophysics Data System (ADS)

    Joe, In-Sung

    Internet traffic nearly doubles every year, and we need faster routers with higher ports count, yet lower electrical power consumption. Current internet routers use electrical switches that consume large amounts of electrical power to operate at high data rates. These internet routers dissipate ˜ 10kW per rack, and their capacity is limited by cooling constraints. The power consumption is also critical for moving platforms. As avionics advance, the demand for larger capacity networks increases. Optical fibers are already chosen for high speed data transmission in advanced aircraft. In optical communication systems, integrated passive optical components, such as Array Waveguide Gratings (AWGs), have provided larger capacity with lower power consumption, because minimal electrical power is required for their operation. In addition, compact, wavelength-tunable semiconductor lasers with wide tuning ranges that can switch their wavelengths in tens of nanoseconds have been demonstrated. Here we present a wavelength-selective optical packet switch based on Waveguide Grating Routers (WGRs), passive splitters, and combiners. Tunable lasers on the transmitter side are the only active switching elements. The WGR is operated on multiple Free Spectral Ranges (FSRs) to achieve increased port count and switching capacity while maintaining strict-sense, non-blocking operation. Switching times of less than 24ns between two wavelengths covering three FSRs is demonstrated experimentally. The electrical power consumption, size, weight, and cost of our optical switch is compared with those of conventional electrical switches, showing substantial improvements at large throughputs (˜2 Tb/s full duplex). A revised switch design that does not suffer optical loss from star couplers is proposed. This switch design uses only WGRs, and it is suitable for networks with stringent power budgets. The burst nature of the optical packet transmission requires clock recovery for every incoming

  18. Plasma-puff initiation of high Coulomb transfer switches

    NASA Technical Reports Server (NTRS)

    Han, Kwang S.; Venable, Demetrius D.; Lee, Ja H.; Choi, Eun H.; Kim, Y. K.; Kim, J. H.; Nguyen, D. X.

    1993-01-01

    The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. The optimal fill gas pressures for the azimuthally uniform plasma-puff were about 120 mTorr less than P(sub opt) less than 450 Torr for He and N2. For Argon 20 mTorr is less than P(sub opt) is less than 5 Torr. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with hypocycloidal pinch plasma-puff triggering. The main discharge of the inverse pinch switch with the plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with the hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. In order to assess the effects of plasma current density on material erosion of electrodes, emissions from both an inverse-pinch plasma switch (INPIStron) and from a spark gap switch under test were studied with an optical multichannel analyzer (OMA). The color temperature of the argon plasma was approximately 4,000 K which corresponded with the peak continuum emission near 750 nm. There are the strong line emissions of argon in the 650 - 800 nm range and a lack of line emissions of copper and other solid material used in the switch. This indicates that the plasma current density during closing is low and the hot spot or hot filament in the switch is negligible. This result also indicates considerable reduction of line emission with the INPIStron switch over that of a spark-gap switch. However, a strong carbon

  19. Plasma-puff initiation of high Coulomb transfer switches

    NASA Technical Reports Server (NTRS)

    Venable, D. D.; Han, K. S.

    1993-01-01

    The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. The optimal fill gas pressures for the azimuthally uniform plasma-puff were about 120 mTorr less than P(opt) less than 450 Torr for He and N2. For Argon 120 mTorr less than P(opt) less than 5 Torr for argon. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with hypocycloidal pinch plasma-puff triggering. The main discharge of the inverse pinch switch with the plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with the hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. In order to assess the effects of plasma current density on material erosion of electrodes, emissions from both an inverse-pinch plasma switch (INPIStron) and from a spark gap switch under test were studied with an optical multichannel analyzer (OMA). The color temperature of the argon plasma was approximately 4,000 K which corresponded with the peak continuum emission near 750 nm. There are the strong line emissions of argon in the 650 - 800 nm range and a lack of line emissions of copper and other solid material used in the switch. This indicates that the plasma current density during closing is low and the hot spot or hot filament in the switch is negligible. This result also indicates considerable reduction of line emission with the INPIStron switch over that of a spark-gap switch. However, a strong carbon line

  20. 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.

  1. 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

  2. Between-Person and Within-Person Associations among Processing Speed, Attention Switching and Working Memory in Younger and Older Adults

    PubMed Central

    Stawski, Robert S.; Sliwinski, Martin J.; Hofer, Scott M.

    2013-01-01

    Background/Study Context Theories of cognitive aging predict associations among processes that transpire within individuals, but are often tested by examining between-person relationships. The authors provide an empirical demonstration of how associations among measures of processing speed, attention switching, and working memory are different when considered between persons versus within persons over time. Methods A sample of 108 older adults (Mage: 80.8, range: 66–95) and 68 younger adults (Mage: 20.2, range:18–24) completed measures of processing speed, attention switching, and working memory on six occasions over a 14-day period. Multilevel modeling was used to examine processing speed and attention switching performance as predictors of working memory performance simultaneously across days (within-person) and across individuals (between-person). Results The findings indicates that simple comparison and response speed predicted working memory better than attention switching between persons, whereas attention switching predicted working memory better than simple comparison and response speed within persons over time. Furthermore, the authors did not observe strong evidence of age differences in these associations either within or between persons. Conclusion The findings of the current study suggest that processing speed is important for understanding between-person and age-related differences in working memory, whereas attention switching is more important for understanding within-person variation in working memory. The authors conclude that theories of cognitive aging should be evaluated by analysis of within-person processes, not exclusively age-related individual differences. PMID:23421639

  3. Simple Short-Pulse CO2 Laser Excited by Longitudinal Discharge without High-Voltage Switch

    NASA Astrophysics Data System (ADS)

    Uno, Kazuyuki; Jitsuno, Takahisa; Akitsu, Tetsuya

    2012-05-01

    We have developed a longitudinally excited CO2 laser without a high-voltage switch. The laser produces a short laser pulse similar to those from TEA and Q-switched CO2 lasers. This system, which is the simplest short-pulse CO2 laser yet constructed, includes a pulsed power supply, a high-speed step-up transformer, a storage capacitor, and a laser tube. At high pressure (4.2 kPa and above), a rapid discharge produces a short laser pulse with a sharp spike pulse. In mixed gas (CO2: N2: He = 1: 1: 2) at a pressure of 9.0 kPa, the laser pulse contains a spike pulse of 218 ns and has a pulse tail length of 16.7 μs.

  4. High-contrast and fast electrochromic switching enabled by plasmonics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Talin, A. Alec

    2016-09-01

    With vibrant colors and simple, room-temperature processing methods, electrochromic polymers have long attracted attention as active materials for flexible, low-power consuming devices such as smart windows and displays. However, despite their many advantages, slow switching speed and complexity of combining several separate polymers to achieve full-color gamut has limited electrochromic materials to niche applications. Here we exploit the enhanced light-matter interaction associated with the deep-subwavelength mode confinement of surface plasmon polaritons propagating in metallic nanoslit arrays coated with ultra-thin electrochromic polymers to build a novel configuration for achieving high-contrast and fast electrochromic switching. The switchable configuration retains the short temporal charge-diffusion characteristics of thin electrochromic films while maintaining the high optical-contrast associated with thicker electrochromic coatings. We further demonstrate that by controlling the pitch of the nanoslit arrays, it is possible to achieve a full-color response with high-contrast and fast switching-speeds while relying on just one electrochromic polymer.

  5. 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

  6. Hydrogel-stabilized droplet bilayers for high speed solution exchange.

    PubMed

    Acharya, Shiv A; Portman, Alexander; Salazar, Carl S; Schmidt, Jacob J

    2013-11-05

    Many applications utilizing artificial lipid bilayers require the ability to exchange the bilayer's solution environment. However, because of the instability of the bilayer, the rate of solution exchange is limited, which significantly hinders the measurement rate and throughput. We have developed an artificial bilayer system that can withstand high flow speeds, up to 2.1 m/s, by supporting the bilayer with a hydrogel. We demonstrated the ability to measure during flow by measuring the conductance of gramicidin-A channels while switching between solutions of two different compositions, recording a time to measure 90% change in current of approximately 2.7 seconds at a flow rate of 0.1 m/s. We also demonstrated a potential application of this system by measuring the conductance modulation of the rat TRPM8 ion channel by an agonist and antagonist at varying concentrations, obtaining 7-point IC50 and EC50 values in approximately 7 minutes and 4-point values within 4 minutes.

  7. 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.

  8. 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.

  9. High speed, high temperature electrical characterization of phase change materials: metastable phases, crystallization dynamics, and resistance drift

    NASA Astrophysics Data System (ADS)

    Dirisaglik, Faruk; Bakan, Gokhan; Jurado, Zoila; Muneer, Sadid; Akbulut, Mustafa; Rarey, Jonathan; Sullivan, Lindsay; Wennberg, Maren; King, Adrienne; Zhang, Lingyi; Nowak, Rebecca; Lam, Chung; Silva, Helena; Gokirmak, Ali

    2015-10-01

    During the fast switching in Ge2Sb2Te5 phase change memory devices, both the amorphous and fcc crystalline phases remain metastable beyond the fcc and hexagonal transition temperatures respectively. In this work, the metastable electrical properties together with crystallization times and resistance drift behaviour of GST are studied using a high-speed, device-level characterization technique in the temperature range of 300 K to 675 K.During the fast switching in Ge2Sb2Te5 phase change memory devices, both the amorphous and fcc crystalline phases remain metastable beyond the fcc and hexagonal transition temperatures respectively. In this work, the metastable electrical properties together with crystallization times and resistance drift behaviour of GST are studied using a high-speed, device-level characterization technique in the temperature range of 300 K to 675 K. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05512a

  10. Advanced Ultra-High Speed Motor for Drilling

    SciTech Connect

    Impact Technologies LLC; University of Texas at Arlington

    2007-03-31

    Three (3) designs have been made for two sizes, 6.91 cm (2.72 inch) and 4.29 cm (1.69 inch) outer diameters, of a patented inverted configured Permanent Magnet Synchronous Machines (PMSM) electric motor specifically for drilling at ultra-high rotational speeds (10,000 rpm) and that can utilize advanced drilling methods. Benefits of these motors are stackable power sections, full control (speed and direction) of downhole motors, flow hydraulics independent of motor operation, application of advanced drilling methods (water jetting and abrasive slurry jetting), and the ability of signal/power electric wires through motor(s). Key features of the final designed motors are: fixed non-rotating shaft with stator coils attached; rotating housing with permanent magnet (PM) rotor attached; bit attached to rotating housing; internal channel(s) in a nonrotating shaft; electric components that are hydrostatically isolated from high internal pressure circulating fluids ('muds') by static metal to metal seals; liquid filled motor with smoothed features for minimized turbulence in the motor during operation; and new inverted coated metal-metal hydrodynamic bearings and seals. PMSM, Induction and Switched Reluctance Machines (SRM), all pulse modulated, were considered, but PMSM were determined to provide the highest power density for the shortest motors. Both radial and axial electric PMSM driven motors were designed with axial designs deemed more rugged for ultra-high speed, drilling applications. The 6.91 cm (2.72 inch) OD axial inverted motor can generate 4.18KW (5.61 Hp) power at 10,000 rpm with a 4 Nm (2.95 ft-lbs) of torque for every 30.48 cm (12 inches) of power section. The 6.91 cm (2.72 inch) OD radial inverted motor can generate 5.03 KW (6.74 Hp) with 4.8 Nm (3.54 ft-lb) torque at 10,000 rpm for every 30.48 cm (12 inches) of power section. The 4.29 cm (1.69 inch) OD radial inverted motor can generate 2.56 KW (3.43 Hp) power with 2.44 Nm (1.8 ft-lb) torque at full speed 10

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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...

  16. 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...

  17. High performance packet switches for broadband satellite networks

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Luo, Fengguang; Luo, Zhixiang

    2005-11-01

    Buffered crossbar switches are now becoming very attractive for the high performance packet switches. An architecture that combines the VOQ architecture and internal buffers can eradicate the HOL problems and reducing the output contention. The architecture predominance and the internal distributed arbitration can fit the broadband satellite networks very well. We propose a new scheduling scheme named Rate Durative (RD), which a VOQ is served continuously at the same time considering its priority level under certain rules. Our scheme was shown to handle traffic more efficiently and better than previous schemes. In addition, this scheduling scheme also supports QoS very well

  18. High-Power Microwave Switch Employing Electron Beam Triggering

    SciTech Connect

    Hirshfield, Jay L

    2012-09-19

    A high-power active microwave pulse compressor is described that modulates the quality factor Q of the energy storage cavity by a new means involving mode conversion controlled by a triggered electron-beam discharge through a switch cavity. The electron beam is emitted from a diamond-coated molybdenum cathode. This report describes the principle of operation, the design of the switch, the configuration used for the test, and the experimental results. The pulse compressor produced output pulses with 140 - 165 MW peak power, power gain of 16 - 20, and pulse duration of 16 - 20 ns at a frequency of 11.43 GHz.

  19. The effect of tip speed ratio on a vertical axis wind turbine at high Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Parker, Colin M.; Leftwich, Megan C.

    2016-05-01

    This work visualizes the flow surrounding a scaled model vertical axis wind turbine at realistic operating conditions. The model closely matches geometric and dynamic properties—tip speed ratio and Reynolds number—of a full-size turbine. The flow is visualized using particle imaging velocimetry (PIV) in the midplane upstream, around, and after (up to 4 turbine diameters downstream) the turbine, as well as a vertical plane behind the turbine. Time-averaged results show an asymmetric wake behind the turbine, regardless of tip speed ratio, with a larger velocity deficit for a higher tip speed ratio. For the higher tip speed ratio, an area of averaged flow reversal is present with a maximum reverse flow of -0.04U_∞. Phase-averaged vorticity fields—achieved by syncing the PIV system with the rotation of the turbine—show distinct structures form from each turbine blade. There were distinct differences in results by tip speed ratios of 0.9, 1.3, and 2.2 of when in the cycle structures are shed into the wake—switching from two pairs to a single pair of vortices being shed—and how they convect into the wake—the middle tip speed ratio vortices convect downstream inside the wake, while the high tip speed ratio pair is shed into the shear layer of the wake. Finally, results show that the wake structure is much more sensitive to changes in tip speed ratio than to changes in Reynolds number.

  20. How to optimize switch virtual keyboards to trade off speed and accuracy.

    PubMed

    Zhang, Xiao; Fang, Kan; Francis, Gregory

    2016-01-01

    In some circumstances, people interact with a virtual keyboard by triggering a binary switch to guide a moving cursor to target characters or items. Such switch keyboards are commonly used by patients with severely restricted motor capabilities. Typing with such systems enables patients to interact with colleagues, but it is slow and error prone. We develop a methodology that can automate an important part of the design process for optimally structured switch keyboards. We show how to optimize the design of simple switch keyboard systems in a way that minimizes the average entry time while satisfying an acceptable error rate. The first step is to model the user's ability to use a switch keyboard correctly for different cursor durations. Once the model is defined, our optimization approach assigns characters to locations on the keyboard, identifies an optimal cursor duration, and considers a variety of cursor paths. For our particular case, we show how to build a user model from empirical data and demonstrate that the resulting optimized keyboards are quite different from existing keyboard designs.

  1. All-optical high performance graphene-photonic crystal switch

    NASA Astrophysics Data System (ADS)

    Hoseini, Mehrdad; Malekmohammad, Mohammad

    2017-01-01

    The all-optical switch is realized based on nonlinear transmission changes in Fano resonance of 2D photonic crystals (PhC) which enhances the light intensity on the graphene in PhC; and in this study, the graphene layer is used as the nonlinear material. The refractive index change of graphene layer leads to a shift in the Fano resonance frequency due to the input light intensity through the Kerr nonlinear effect. Through finite-difference time-domain simulation, it is found that the high performance of all-optical switching can be achieved by the designed structure with a threshold pump intensity as low as MW/cm2. This structure is featured by optical bistability. The obtained results are applicable in micro optical integrated circuits for modulators, switches and logic elements for optical computation.

  2. High speed, high temperature electrical characterization of phase change materials: metastable phases, crystallization dynamics, and resistance drift.

    PubMed

    Dirisaglik, Faruk; Bakan, Gokhan; Jurado, Zoila; Muneer, Sadid; Akbulut, Mustafa; Rarey, Jonathan; Sullivan, Lindsay; Wennberg, Maren; King, Adrienne; Zhang, Lingyi; Nowak, Rebecca; Lam, Chung; Silva, Helena; Gokirmak, Ali

    2015-10-28

    During the fast switching in Ge2Sb2Te5 phase change memory devices, both the amorphous and fcc crystalline phases remain metastable beyond the fcc and hexagonal transition temperatures respectively. In this work, the metastable electrical properties together with crystallization times and resistance drift behaviour of GST are studied using a high-speed, device-level characterization technique in the temperature range of 300 K to 675 K.

  3. Approximate solution for high-frequency Q-switched lasers.

    PubMed

    Agnesi, Antonio

    2016-06-01

    A simple approximation for the energy, pulse width, and build-up time valid for high-repetition-rate Q-switched lasers is discussed. This particular regime of operation is most common in industrial applications where manufacturing time must be minimized. Limits of validity and some considerations for the choice of the most appropriate laser system for specific applications are briefly discussed.

  4. High-Speed Optical Diagnostics of Laser-Interactions

    NASA Astrophysics Data System (ADS)

    Bin Suaidi, Mohamad Kadim

    Available from UMI in association with The British Library. The interaction of an 8 ns, 10 mJ and 1.06 μm infrared pulse of radiation from a Q-switched Nd-YAG laser with water near a solid boundary is studied using high speed photographic techniques. The laser-liquid interaction has been used to generate high frequency sound waves by the mechanism of dielectric breakdown of the liquid around the beam waist of the focused laser beam. This leads to the production of a short duration plasma which rapidly heats and vaporises the surrounding liquid giving rise to a vapour cavity and the formation of a cavitation bubble resulting in the emission of a spherical acoustic wave. The acoustic transient associated with the breakdown, in turn interacted with a liquid-polymer interface leading to the generation of acoustic waves at this boundary and the propagation of stress-waves in the solid. Diagnostics of the laser-interaction events are recorded using a Mach-Zehnder interferometer illuminated by a sub-nanosecond nitrogen laser-pumped dye laser and computer-controlled video-imaging and capture systems. Measurements of the transient pressure distributions from the digitally recorded interferograms are carried out using a process known as Abel inversion. Dynamic photoelastic studies of the stress-waves propagation in the solid are performed using a circular polariscope arrangement thus producing the photoelastic fringe patterns. Identification of the wave structures are greatly enhanced by also recording the events in schlieren and focused shadowgraphy as well as by the combination of the above techniques. The initial part of the project also involved the design and development of a nitrogen laser and tunable dye laser system. The short-duration and high peak power output pulse of the nitrogen laser is then used to pump the dye laser giving sufficiently high power output with good spectral linewidth to provide an ideal light source for high-speed photography of the laser

  5. 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

  6. 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.

  7. High power, electron-beam induced switching in diamond

    SciTech Connect

    Scarpetti, R.D.; Hofer, W.W.; Kania, D.R.; Schoenbach, K.H.; Joshi, R.P.; Molina, C.; Brinkmann, R.P.

    1993-07-01

    We are developing a high voltage, high average power, electron-beam controlled diamond switch that could significantly impact high power solid-state electronics in industrial and defense applications. An electron-beam controlled thin-film diamond could switch well over 100 kW average power at MHz frequencies, greater than 5 kV, and with high efficiency. This performance is due to the excellent thermal and electronic properties of diamond, the high efficiency achieved with electron beam control, and the demonstrated effectiveness of microchannel cooling. Our electron beam penetration depth measurements agree with our Monte-Carlo calculations. We have not observed electron beam damage in diamond for beam energies up to 150 keV. In this paper we describe our experimental and calculational results and research objectives.

  8. High gain GaAs Photoconductive Semiconductor Switches (PCSS): Device lifetime, high current testing, optical pulse generators

    SciTech Connect

    Zutavern, F.J.; Loubriel, G.M.; Helgeson, W.D.; O`Malley, M.W.; Gallegos, R.R.; Hjalmarson, H.P.; Baca, A.G.; Plut, T.A.

    1995-12-31

    This paper presents results from three areas of GaAs PCSS research and development: device lifetime, high current switching, and PCSS-driven laser diode arrays (LDA). The authors have performed device lifetime tests on both lateral and vertical switches as a function of current amplitude, pulse width, and charging time. At present, their longest-lived switch reached 4 {times} 10{sup 6} pulses. Scanning electron microscope (SEM) images show damage near the contacts even after only 5 pulses. They are presently searching for the threshold at which no damage is evident after a single shot. In high current tests, they have reached 5.2 kA at 4.2 kV. This was achieved using twenty fiber-optic coupled lasers to distribute current filaments over a 5 mm wide PCSS. Current waveforms and images of the current filaments as a function of current amplitude will be presented. The lasers used to trigger the high current PCSS were driven with a miniature PCSS. Low inductance, high speed GaAs PCSS are very effective as short pulse laser diode array drivers. Some types of arrays gain switch, producing a compressed optical pulse which is only 75 ps wide. Results from tests with a variety of laser diode arrays will be presented.

  9. Gain switching in high power lasers

    NASA Astrophysics Data System (ADS)

    Druehl, K.; Scully, M. O.; Overhauser, A. W.

    1981-09-01

    Consideration is given to situations in which energy could be stored in a metastable state of a high-power laser and then dumped by applying a strong electric field to enhance coupling to the lower state. The electric dipole transitions induced by an external field are compared with magnetic dipole and electric quadrupole radiation due to other types of allowed transitions, and it is noted that in order for the application of the external field to increase the gain coefficient by at least an order of magnitude, the transitions in question must be forbidden for magnetic dipole radiation and occur at wavelengths of 1 to 10 microns. Field-induced transition rates are then calculated for the homonuclear diatomic molecules H2 and N2, along with the gain coefficient for H2. It is pointed out that stronger applied fields capable of increasing the gain may be produced by high-power laser pulses, resulting in gains of several per cent per cm.

  10. 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.

  11. 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.

  12. High thermal stable and fast switching Ni-Ge-Te alloy for phase change memory applications

    NASA Astrophysics Data System (ADS)

    Cao, Liangliang; Wu, Liangcai; Zhu, Wenqing; Ji, Xinglong; Zheng, Yonghui; Song, Zhitang; Rao, Feng; Song, Sannian; Ma, Zhongyuan; Xu, Ling

    2015-12-01

    Ni-Ge-Te phase change material is proposed and investigated for phase change memory (PCM) applications. With Ni addition, the crystallization temperature, the data retention ability, and the crystallization speed are remarkably improved. The Ni-Ge-Te material has a high crystallization temperature (250 °C) and good data retention ability (149 °C). A reversible switching between SET and RESET state can be achieved by an electrical pulse as short as 6 ns. Up to ˜3 × 104 SET/RESET cycles are obtained with a resistance ratio of about two orders of magnitude. All of these demonstrate that Ni-Ge-Te alloy is a promising material for high speed and high temperature PCM applications.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 75 FR 37453 - Notice of Issuance of Final Determination Concerning Dimmer and Fan Speed Switch Controls

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ..., capacitors, diodes, integrated circuits, sockets, and connectors) were assembled. Whether an operation is... switches in the U.S. for residential and commercial use in electrical circuits of less than 1,000 volts... circuit board into a final printed circuit board (``PCB''), and the assembly of the PCB with...

  18. Optical fiber imaging for high speed plasma motion diagnostics: applied to low voltage circuit breakers.

    PubMed

    McBride, J W; Balestrero, A; Ghezzi, L; Tribulato, G; Cross, K J

    2010-05-01

    An integrated portable measurement system is described for the study of high speed and high temperature unsteady plasma flows such as those found in the vicinity of high current switching arcs. An array of optical fibers allows the formation of low spatial resolution images, with a maximum capture rate of 1 x 10(6) images per second (1 MHz), with 8 bit intensity resolution. Novel software techniques are reported to allow imaging of the arc; and to measure arc trajectories. Results are presented on high current (2 kA) discharge events in a model test fixture and on the application to a commercial low voltage circuit breaker.

  19. Optical fiber imaging for high speed plasma motion diagnostics: Applied to low voltage circuit breakers

    SciTech Connect

    McBride, J. W.; Balestrero, A.; Tribulato, G.; Ghezzi, L.; Cross, K. J.

    2010-05-15

    An integrated portable measurement system is described for the study of high speed and high temperature unsteady plasma flows such as those found in the vicinity of high current switching arcs. An array of optical fibers allows the formation of low spatial resolution images, with a maximum capture rate of 1x10{sup 6} images per second (1 MHz), with 8 bit intensity resolution. Novel software techniques are reported to allow imaging of the arc; and to measure arc trajectories. Results are presented on high current (2 kA) discharge events in a model test fixture and on the application to a commercial low voltage circuit breaker.

  20. High-speed, intra-system networks

    SciTech Connect

    Quinn, Heather M; Graham, Paul S; Manuzzato, Andrea; Fairbanks, Tom; Dallmann, Nicholas; Desgeorges, Rose

    2010-06-28

    Recently, engineers have been studying on-payload networks for fast communication paths. Using intra-system networks as a means to connect devices together allows for a flexible payload design that does not rely on dedicated communication paths between devices. In this manner, the data flow architecture of the system can be dynamically reconfigured to allow data routes to be optimized for the application or configured to route around devices that are temporarily or permanently unavailable. To use intra-system networks, devices will need network controllers and switches. These devices are likely to be affected by single-event effects, which could affect data communication. In this paper we will present radiation data and performance analysis for using a Broadcom network controller in a neutron environment.

  1. High Frequency PIN-Diode Switches for Radiometer Applications

    NASA Technical Reports Server (NTRS)

    Montes, Oliver; Dawson, Douglas E.; Kangaslahti, Pekka; Reising, Steven C.

    2011-01-01

    Internally calibrated radiometers are needed for ocean topography and other missions. Typically internal calibration is achieved with Dicke switching as one of the techniques. We have developed high frequency single-pole double-throw (SPDT) switches in the form of monolithic microwave integrated circuits (MMIC) that can be easily integrated into Dicke switched radiometers that utilize microstrip technology. In particular, the switches we developed can be used for a radiometer such as the one proposed for the Surface Water and Ocean Topography (SWOT) Satellite Mission whose three channels at 92, 130, and 166 GHz would allow for wet-tropospheric path delay correction near coastal zones and over land. This feat is not possible with the current Jason-class radiometers due to their lower frequency signal measurement and thus lower resolution. The MMIC chips were fabricated at NGST using their InP PIN diode process and measured at JPL using high frequency test equipment. Measurement and simulation results will be presented.

  2. High Frequency PIN-Diode Switches for Radiometer Applications

    NASA Technical Reports Server (NTRS)

    Montes, Oliver; Dawson, Douglas E.; Kangaslahti, Pekka; Reising, Steven C.

    2011-01-01

    Internally calibrated radiometers are needed for ocean topography and other missions. Typically internal calibration is achieved with Dicke switching as one of the techniques. We have developed high frequency single-pole double-throw (SPDT) switches in the form of monolithic microwave integrated circuits (MMIC) that can be easily integrated into Dicke switched radiometers that utilize microstrip technology. In particular, the switches we developed can be used for a radiometer such as the one proposed for the Surface Water and Ocean Topography (SWOT) Satellite Mission whose three channels at 92, 130, and 166 GHz would allow for wet-tropospheric path delay correction near coastal zones and over land. This feat is not possible with the current Jason-class radiometers due to their lower frequency signal measurement and thus lower resolution. The MMIC chips were fabricated at NGST using their InP PIN diode process and measured at JPL using high frequency test equipment. Measurement and simulation results will be presented.

  3. Utility-scale variable-speed wind turbines using a doubly-fed generator with a soft-switching power converter

    SciTech Connect

    Weigand, C.H.; Lauw, H.K.; Marckx, D.A.

    1996-12-31

    Utility-scale wind turbines operating at variable RPM have been studied for a considerable period of time. Whereas the increase in energy output originally has been considered the principal benefit of variable-speed operation, the ability to tightly control the drive-train torque by electronic means is becoming another very important cost factor, especially for turbine ratings above 500 kilowatts. This cost benefit becomes even more significant as optimum turbine ratings today are approaching (and surpassing) 1 Megawatt. Having identified the benefits for the turbine, the designer is confronted with the task of finding the most cost-effective variable-speed generation system which allows him to make use of the benefits, yet does not introduce well-known electrical problems associated with state-of-the-art variable-speed generator controls, such as drastically reduced generator winding life, excessive harmonics on the utility, and poor utility power factor. This paper will indicate that for high-power (> 500 kW), utility-scale wind turbines a doubly-fed generator system in connection with a soft-switching resonant power converter is the least-cost variable-speed generation system offering all of the desired benefits, yet avoids the introduction of the potential electrical problems stated above. 3 refs., 3 figs., 1 tab.

  4. 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.

  5. High-Resolution Mammography Detector Employing Optical Switching Readout

    NASA Astrophysics Data System (ADS)

    Irisawa, Kaku; Kaneko, Yasuhisa; Yamane, Katsutoshi; Sendai, Tomonari; Hosoi, Yuichi

    Conceiving a new detector structure, FUJIFILM Corporation has successfully put its invention of an X-ray detector employing "Optical Switching" into practical use. Since Optical Switching Technology allows an electrode structure to be easily designed, both high resolution of pixel pitch and low electrical noise readout have been achieved, which have consequently realized the world's smallest pixel size of 50×50 μm2 from a Direct-conversion FPD system as well as high DQE. The digital mammography system equipped with this detector enables to acquire high definition images while maintaining granularity. Its outstanding feature is to be able to acquire high-precision images of microcalcifications which is an important index in breast examination.

  6. 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.

  7. 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

  8. 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

  9. 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),…

  10. 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...

  11. 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

  12. 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...

  13. 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…

  14. 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...

  15. 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...

  16. 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…

  17. 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

  18. 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.

  19. 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.

  20. Steady State Analysis Of The Variable Speed Switched Reluctance Motor Drive

    NASA Astrophysics Data System (ADS)

    Materu, P.; Krishnan, R.; Farzanehfard, H.

    1987-10-01

    The switched reluctance motor (SRM) drive has recently received attention mainly because of its simple motor construction and unidirectional converter requirement. The principle of operation of the motor drive demands that the motor and converter be treated as one unit. Little has been done to develop a complete analysis of this motor-converter combination 1'2. This paper presents an approach to the steady state analysis of the SRM drive including the effects of stator winding resistance, input filter dynamics and snubber circuits which are often neglected. The analysis yields phase current waveforms providing guidelines to the optimal design of the converter and motor. A novel single-switch-per phase converter developed by one of the authors is used. The approach can be used for any other motor-converter combination.

  1. Pulsed laser triggered high speed microfluidic fluorescence activated cell sorter†‡

    PubMed Central

    Wu, Ting-Hsiang; Chen, Yue; Park, Sung-Yong; Hong, Jason; Teslaa, Tara; Zhong, Jiang F.; Di Carlo, Dino; Teitell, Michael A.

    2014-01-01

    We report a high speed and high purity pulsed laser triggered fluorescence activated cell sorter (PLACS) with a sorting throughput up to 20 000 mammalian cells s−1 with 37% sorting purity, 90% cell viability in enrichment mode, and >90% purity in high purity mode at 1500 cells s−1 or 3000 beads s−1. Fast switching (30 μs) and a small perturbation volume (~90 pL) is achieved by a unique sorting mechanism in which explosive vapor bubbles are generated using focused laser pulses in a single layer microfluidic PDMS channel. PMID:22361780

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Active high-power RF switch and pulse compression system

    DOEpatents

    Tantawi, Sami G.; Ruth, Ronald D.; Zolotorev, Max

    1998-01-01

    A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

  9. 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.

  10. 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.

  11. Solid state switch for high reliability spacecraft use

    SciTech Connect

    Kamon, D.; Dalton, J.F.

    1995-12-31

    The drive to improve interplanetary spacecraft power system reliability and fault tolerance spurred JPL to develop a Solid State Power Switch (SSPS). JPL began the development of the SSPS in the late nineteen eighties to replace the traditional mechanical relay/fuse combination with high reliability solid state designs that provide distributed fault protection and load switching. The JPL design was driven by the high reliability, fault tolerant requirements of the Cassini mission to Saturn (late 1997 launch). The Cassini spacecraft will be the first JPL spacecraft to utilize a solid state device for power distribution. One hundred and ninety-two (192) SSPS hybrid units will be used to control numerous spacecraft loads. The system approach and design philosophy of the SSPS were previously reported at the 1994, 29th IECEC conference (Dalton, et al.). This paper describes the design and implementation of the flight qualified hybridized SSPS.

  12. Analysis of tri-stage memory array for high-speed packet buffers

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Jin, Depeng; Zeng, Lieguang

    2005-02-01

    The speed of high-performance switches and routers is often limited by the bandwidth of commercially available memories. Meanwhile, the rapid growth in network bandwidth accompanied by the slowly increasing memory speed makes the problem even harder over time. There are, in fact, several techniques to build faster memories. However, some are based on the ideas from computer systems, such as parallelism, interleaving and banking, which can hardly be applied directly to packet buffering, while the others like hybrid SRAM-DRAM packet buffers are restricted by the speed of SRAM and inapplicable as the link rate exceeds the speed of SRAM. Motivated by increasing the throughput of packet buffers with only common memory arrays, we present one particular packet buffer architecture called Tri-Stage Memory Array (TSMA) that can speed up the packet buffering and retrieving processes to an arbitrary high speed theoretically. To replenish TSMA, a memory management algorithm called Most Urgent Queue First (MUQF) is also described and analyzed. It is proved that TSMA architecture coupled with MUQF algorithm can guarantee a bounded delay for each packet under any traffic arrival pattern or scheduling algorithm. Moreover, we provide an alternative architecture of TSMA to achieve simple implementation.

  13. 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.

  14. Single Longitudinal Mode, High Repetition Rate, Q-switched Ho:YLF Laser for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Bai, Yingxin; Yu, Jirong; Petzar, Paul; Petros, M.; Chen, Songsheng; Trieu, Bo; Lee, Nyung; Singh, U.

    2009-01-01

    Ho:YLF/LuLiF lasers have specific applications for remote sensing such as wind-speed measurement and carbon dioxide (CO2) concentration measurement in the atmosphere because the operating wavelength (around 2 m) is located in the eye-safe range and can be tuned to the characteristic lines of CO2 absorption and there is strong backward scattering signal from aerosol (Mie scattering). Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of with a repetition rate of 5 Hz and pulse energy of 75 mJ [1]. For highly precise CO2 measurements with coherent detection technique, a laser with high repetition rate is required to averaging out the speckle effect [2]. In addition, laser efficiency is critically important for the air/space borne lidar applications, because of the limited power supply. A diode pumped Ho:Tm:YLF laser is difficult to efficiently operate in high repetition rate due to the large heat loading and up-conversion. However, a Tm:fiber laser pumped Ho:YLF laser with low heat loading can be operated at high repetition rates efficiently [3]. No matter whether wind-speed or carbon dioxide (CO2) concentration measurement is the goal, a Ho:YLF/LuLiF laser as the transmitter should operate in a single longitudinal mode. Injection seeding is a valid technique for a Q-switched laser to obtain single longitudinal mode operation. In this paper, we will report the new results for a single longitudinal mode, high repetition rate, Q-switched Ho:YLF laser. In order to avoid spectral hole burning and make injection seeding easier, a four mirror ring cavity is designed for single longitudinal mode, high repetition rate Q-switched Ho:YLF laser. The ramp-fire technique is chosen for injection seeding.

  15. Single Longitudinal Mode, High Repetition Rate, Q-switched Ho:YLF Laser for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Bai, Yingxin; Yu, Jirong; Petzar, Paul; Petros, M.; Chen, Songsheng; Trieu, Bo; Lee, Nyung; Singh, U.

    2009-01-01

    Ho:YLF/LuLiF lasers have specific applications for remote sensing such as wind-speed measurement and carbon dioxide (CO2) concentration measurement in the atmosphere because the operating wavelength (around 2 m) is located in the eye-safe range and can be tuned to the characteristic lines of CO2 absorption and there is strong backward scattering signal from aerosol (Mie scattering). Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of with a repetition rate of 5 Hz and pulse energy of 75 mJ [1]. For highly precise CO2 measurements with coherent detection technique, a laser with high repetition rate is required to averaging out the speckle effect [2]. In addition, laser efficiency is critically important for the air/space borne lidar applications, because of the limited power supply. A diode pumped Ho:Tm:YLF laser is difficult to efficiently operate in high repetition rate due to the large heat loading and up-conversion. However, a Tm:fiber laser pumped Ho:YLF laser with low heat loading can be operated at high repetition rates efficiently [3]. No matter whether wind-speed or carbon dioxide (CO2) concentration measurement is the goal, a Ho:YLF/LuLiF laser as the transmitter should operate in a single longitudinal mode. Injection seeding is a valid technique for a Q-switched laser to obtain single longitudinal mode operation. In this paper, we will report the new results for a single longitudinal mode, high repetition rate, Q-switched Ho:YLF laser. In order to avoid spectral hole burning and make injection seeding easier, a four mirror ring cavity is designed for single longitudinal mode, high repetition rate Q-switched Ho:YLF laser. The ramp-fire technique is chosen for injection seeding.

  16. Nanosecond high-power dense microplasma switch for visible light

    SciTech Connect

    Bataller, A. Koulakis, J.; Pree, S.; Putterman, S.

    2014-12-01

    Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.

  17. High-current, fast-switching transistor development

    NASA Technical Reports Server (NTRS)

    Hower, P. L.

    1981-01-01

    The design, wafer-processing techniques, and various measurements which include forward safe operating area, dc characteristics, and switching times are described for a larger-diameter (33) transistor. An improved base contact for equalizing the base-emitter voltage at high currents was developed along with an improved emitter contact preform which increases the silicon area available for current conduction. The electrical performance achieved is consistent with the proposed optimum design.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. Response characteristic of high-speed on/off valve with double voltage driving circuit

    NASA Astrophysics Data System (ADS)

    Li, P. X.; Su, M.; Zhang, D. B.

    2017-07-01

    High-speed on/off valve, an important part of turbocharging system, its quick response has a direct impact on the turbocharger pressure cycle. The methods of improving the response characteristic of high speed on/off valve include increasing the magnetic force of armature and the voltage, decreasing the mass and current of coil. The less coil number of turns, the solenoid force is smaller. The special armature structure and the magnetic material will raise cost. In this paper a new scheme of double voltage driving circuit is investigated, in which the original driving circuit of high-speed on/off valve is replaced by double voltage driving circuit. The detailed theoretical analysis and simulations were carried out on the double voltage driving circuit, it showed that the switching time and delay time of the valve respectively are 3.3ms, 5.3ms, 1.9ms and 1.8ms. When it is driven by the double voltage driving circuit, the switching time and delay time of this valve are reduced, optimizing its response characteristic. By the comparison related factors (such as duty cycle or working frequency) about influences on response characteristic, the superior of double voltage driving circuit has been further confirmed.

  8. Piezoelectronics: a novel, high-performance, low-power computer switching technology

    NASA Astrophysics Data System (ADS)

    Newns, D. M.; Martyna, G. J.; Elmegreen, B. G.; Liu, X.-H.; Theis, T. N.; Trolier-McKinstry, S.

    2012-06-01

    Current switching speeds in CMOS technology have saturated since 2003 due to power constraints arising from the inability of line voltage to be further lowered in CMOS below about 1V. We are developing a novel switching technology based on piezoelectrically transducing the input or gate voltage into an acoustic wave which compresses a piezoresistive (PR) material forming the device channel. Under pressure the PR undergoes an insulator-to-metal transition which makes the channel conducting, turning on the device. A piezoelectric (PE) transducer material with a high piezoelectric coefficient, e.g. a domain-engineered relaxor piezoelectric, is needed to achieve low voltage operation. Suitable channel materials manifesting a pressure-induced metal-insulator transition can be found amongst rare earth chalcogenides, transition metal oxides, etc.. Mechanical requirements include a high PE/PR area ratio to step up pressure, a rigid surround material to constrain the PE and PR external boundaries normal to the strain axis, and a void space to enable free motion of the component side walls. Using static mechanical modeling and dynamic electroacoustic simulations, we optimize device structure and materials and predict performance. The device, termed a PiezoElectronic Transistor (PET) can be used to build complete logic circuits including inverters, flip-flops, and gates. This "Piezotronic" logic is predicted to have a combination of low power and high speed operation.

  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. Miniaturized, High-Speed, Modulated X-Ray Source

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith; Arzoumanian, Zaven; Kenyon, Steve; Spartana, Nick

    2013-01-01

    A low-cost, miniature x-ray source has been developed that can be modulated in intensity from completely off to full intensity on nanosecond timescales. This modulated x-ray source (MXS) has no filaments and is extremely rugged. The energy level of the MXS is adjustable from 0 to more than 100 keV. It can be used as the core of many new devices, providing the first practical, arbitrarily time-variable source of x-rays. The high-speed switching capability and miniature size make possible many new technologies including x-ray-based communication, compact time-resolved x-ray diffraction, novel x-ray fluorescence instruments, and low- and precise-dose medical x-rays. To make x-rays, the usual method is to accelerate electrons into a target material held at a high potential. When the electrons stop in the target, x-rays are produced with a spectrum that is a function of the target material and the energy to which the electrons are accelerated. Most commonly, the electrons come from a hot filament. In the MXS, the electrons start off as optically driven photoelectrons. The modulation of the x-rays is then tied to the modulation of the light that drives the photoelectron source. Much of the recent development has consisted of creating a photoelectrically-driven electron source that is robust, low in cost, and offers high intensity. For robustness, metal photocathodes were adopted, including aluminum and magnesium. Ultraviolet light from 255- to 350-nm LEDs (light emitting diodes) stimulated the photoemissions from these photocathodes with an efficiency that is maximized at the low-wavelength end (255 nm) to a value of roughly 10(exp -4). The MXS units now have much higher brightness, are much smaller, and are made using a number of commercially available components, making them extremely inexpensive. In the latest MXS design, UV efficiency is addressed by using a high-gain electron multiplier. The photocathode is vapor-deposited onto the input cone of a Burle Magnum

  11. A design approach to real-time formatting of high speed multispectral image data

    NASA Technical Reports Server (NTRS)

    Meredith, B. D.; Kelly, W. L., IV

    1981-01-01

    A design approach to formatting multispectral image data in real time at very high data rates is presented for future onboard processing applications. The approach employs a microprocessor-based alternating buffer memory configuration whose formatting function is completely programmable. Data are read from an output buffer in the desired format by applying the proper sequence of addresses to the buffer via a lookup table memory. Sensor data can be processed using this approach at rates limited by the buffer memory access time and the buffer switching process delay time. This design offers flexible high speed data processing and benefits from continuing increases in the performance of digital memories.

  12. Solvent-induced high fidelity switching between two discrete supramolecules.

    PubMed

    Betancourt, José E; Martín-Hidalgo, Mariana; Gubala, Vladimir; Rivera, José M

    2009-03-11

    Here we show the reversible high fidelity switching between two discrete self-assembled supramolecules made from a lipophilic 8-phenyl-2'-deoxyguanosine derivative induced by an indirect solvent effect. A hexadecameric supramolecule containing four stacked tetramers is formed in acetonitrile aided by higher potassium concentrations. When the amount of weakly solvated potassium decreases, due the lower activity of potassium iodide in chloroform, an octamer is formed after the dissociation of the two outer tetramers in the hexadecamer. The switching process results from an unprecedented subtle interplay between the activity of potassium iodide and the steric crowding within the self-assembled structure. Besides the possible applications in nanoconstruction, this phenomenon sheds light into the mechanism of formation of self-assembled supramolecules made from guanosine derivatives.

  13. Plasma Switch for High-Power Active Pulse Compressor

    SciTech Connect

    Hirshfield, Jay L.

    2013-11-04

    Results are presented from experiments carried out at the Naval Research Laboratory X-band magnicon facility on a two-channel X-band active RF pulse compressor that employed plasma switches. Experimental evidence is shown to validate the basic goals of the project, which include: simultaneous firing of plasma switches in both channels of the RF circuit, operation of quasi-optical 3-dB hybrid directional coupler coherent superposition of RF compressed pulses from both channels, and operation of the X-band magnicon directly in the RF pulse compressor. For incident 1.2 ?s pulses in the range 0.63 ? 1.35 MW, compressed pulses of peak powers 5.7 ? 11.3 MW were obtained, corresponding to peak power gain ratios of 8.3 ? 9.3. Insufficient bakeout and conditioning of the high-power RF circuit prevented experiments from being conducted at higher RF input power levels.

  14. State switching in regions of high modal density

    NASA Astrophysics Data System (ADS)

    Lopp, Garrett K.; Kauffman, Jeffrey L.

    2016-04-01

    Performance of piezoelectric-based, semi-active vibration reduction approaches has been studied extensively in the past decade. Originally analyzed with single-degree-of-freedom systems, these approaches have been extended to multi-mode vibration reduction. However, the accompanying analysis typically assumes well-separated modes, which is often not the case for plate structures. Because the semi-active approaches induce a shift in the structural resonance frequency (at least temporarily), targeting a specific mode for vibration reduction can actually lead to additional vibration in an adjacent mode. This paper presents an analysis using a simplified model of a two-degree-of-freedom mass-spring-damper system with lightly-coupled masses to achieve two closely-spaced modes. This investigation is especially applicable to the resonance frequency detuning approach previously proposed to reduce vibrations caused by transient excitation in turbomachinery blades where regions of high modal density exist. More generally, this paper addresses these effects of stiffness state switches in frequency ranges containing regions of high modal density and subject to frequency sweep excitation. Of the approaches analyzed, synchronized switch damping on an inductor offers the greatest vibration reduction performance, whereas resonance frequency detuning and state switching each yield similar performance. Additionally, as the relative distance between resonance peaks decreases, the performance for the vibration reduction methods approaches that of a single-degree-of-freedom system; however, there are distances between these resonant peaks that diminish vibration reduction potential.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.