WorldWideScience

Sample records for extremely high speeds

  1. High speed digital phonoscopy of selected extreme vocalization (Conference Presentation)

    Science.gov (United States)

    Izdebski, Krzysztof; Blanco, Matthew; Di Lorenzo, Enrico; Yan, Yuling

    2017-02-01

    We used HSDP (KayPENTAX Model 9710, NJ, USA) to capture the kinematics of vocal folds in the production of extreme vocalization used by heavy metal performers. The vibrations of the VF were captured at 4000 f/s using transoral rigid scope. Growl, scream and inhalatory phonations were recoded. Results showed that these extreme sounds are produced predominantly by supraglottic tissues rather than by the true vocal folds, which explains while these sounds do not injure the mucosa of the true vocal folds. In addition, the HSDI were processed using custom software (Vocalizer®) that clearly demonstrated the contribution of each vocal fold to the generation of the sound.

  2. Mesoscale high-resolution modeling of extreme wind speeds over western water areas of the Russian Arctic

    Science.gov (United States)

    Platonov, Vladimir S.; Kislov, Alexander V.

    2016-11-01

    A statistical analysis of extreme weather events over coastal areas of the Russian Arctic based on observational data has revealed many interesting features of wind velocity distributions. It has been shown that the extremes contain data belonging to two different statistical populations. Each of them is reliably described by a Weibull distribution. According to the standard terminology, these sets of extremes are named ‘black swans’ and ‘dragons’. The ‘dragons’ are responsible for most extremes, surpassing the ‘black swans’ by 10 - 30 %. Since the data of the global climate model INM-CM4 do not contain ‘dragons’, the wind speed extremes are investigated on the mesoscale using the COSMO-CLM model. The modelling results reveal no differences between the ‘swans’ and ‘dragons’ situations. It could be associated with the poor sample data used. However, according to many case studies and modeling results we assume that it is caused by a rare superposition of large-scale synoptic factors and many local meso- and microscale factors (surface, coastline configuration, etc.). Further studies of extreme wind speeds in the Arctic, such as ‘black swans’ and ‘dragons’, are necessary to focus on non-hydrostatic high-resolution atmospheric modelling using downscaling techniques.

  3. Estimation of the high-spatial-resolution variability in extreme wind speeds for forestry applications

    Science.gov (United States)

    Venäläinen, Ari; Laapas, Mikko; Pirinen, Pentti; Horttanainen, Matti; Hyvönen, Reijo; Lehtonen, Ilari; Junila, Päivi; Hou, Meiting; Peltola, Heli M.

    2017-07-01

    The bioeconomy has an increasing role to play in climate change mitigation and the sustainable development of national economies. In Finland, a forested country, over 50 % of the current bioeconomy relies on the sustainable management and utilization of forest resources. Wind storms are a major risk that forests are exposed to and high-spatial-resolution analysis of the most vulnerable locations can produce risk assessment of forest management planning. In this paper, we examine the feasibility of the wind multiplier approach for downscaling of maximum wind speed, using 20 m spatial resolution CORINE land-use dataset and high-resolution digital elevation data. A coarse spatial resolution estimate of the 10-year return level of maximum wind speed was obtained from the ERA-Interim reanalyzed data. Using a geospatial re-mapping technique the data were downscaled to 26 meteorological station locations to represent very diverse environments. Applying a comparison, we find that the downscaled 10-year return levels represent 66 % of the observed variation among the stations examined. In addition, the spatial variation in wind-multiplier-downscaled 10-year return level wind was compared with the WAsP model-simulated wind. The heterogeneous test area was situated in northern Finland, and it was found that the major features of the spatial variation were similar, but in some locations, there were relatively large differences. The results indicate that the wind multiplier method offers a pragmatic and computationally feasible tool for identifying at a high spatial resolution those locations with the highest forest wind damage risks. It can also be used to provide the necessary wind climate information for wind damage risk model calculations, thus making it possible to estimate the probability of predicted threshold wind speeds for wind damage and consequently the probability (and amount) of wind damage for certain forest stand configurations.

  4. Polar summer mesospheric extreme horizontal drift speeds during interplanetary corotating interaction regions (CIRs) and high-speed solar wind streams: Coupling between the solar wind and the mesosphere

    Science.gov (United States)

    Lee, Young-Sook; Kirkwood, Sheila; Kwak, Young-Sil; Kim, Kyung-Chan; Shepherd, Gordon G.

    2014-05-01

    We report the observation of echo extreme horizontal drift speed (EEHS, ≥ 300 m s-1) during polar mesospheric (80-90 km) summer echoes (PMSEs) by the VHF (52 MHz) radar at Esrange, Sweden, in years of 2006 and 2008. The EEHS occur in PMSEs as correlated with high-speed solar wind streams (HSSs), observed at least once in 12-17% of all hours of observation for the two summers. The EEHS rate peaks occur either during high solar wind speed in the early part of the PMSE season or during the arrival of interplanetary corotating interaction regions (CIRs) followed by peaks in PMSE occurrence rate after 1-4 days, in the latter part of the 2006 summer. The cause of EEHS rate peaks is likely under the competition between the interval of the CIR and HSS passage over the magnetosphere. A candidate process in producing EEHS is suggested to be localized strong electric field, which is caused by solar wind energy transfer from the interaction of CIR and HSS with the magnetosphere in a sequential manner. We suggest that EEHS are created by strong electric field, estimated as > 10-30 V m-1 at 85 km altitude, exceeding the mesospheric breakdown threshold field.

  5. High speed data converters

    CERN Document Server

    Ali, Ahmed MA

    2016-01-01

    This book covers high speed data converters from the perspective of a leading high speed ADC designer and architect, with a strong emphasis on high speed Nyquist A/D converters. For our purposes, the term 'high speed' is defined as sampling rates that are greater than 10 MS/s.

  6. Comb-based radio-frequency photonic filters: rounts to nanosecond tuning speed and extremely high stopband attenuation

    CERN Document Server

    Supradeepa, V R; Wu, Rui; Ferdous, Fahmida; Hamidi, Ehsan; Leaird, Daniel E; Weiner, Andrew M

    2011-01-01

    Photonic technologies have received considerable attention for enhancement of radio-frequency (RF) electrical systems, including high-frequency analog signal transmission, control of phased arrays, analog-to-digital conversion, and signal processing. Although the potential of radio-frequency photonics for implementation of tunable electrical filters over broad RF bandwidths has been much discussed, realization of programmable filters with highly selective filter lineshapes has faced significant challenges. In this paper we show that a new approach based on optical frequency combs enables dramatic progress. A novel comb generation scheme employing tailored electro-optic modulation and cascaded four-wave mixing results in approximately Gaussian RF filter lineshapes with extremely high (>60 dB) out-of-band suppression. A modification of our approach provides RF filter tuning through optical delay variation and decouples filter tuning and lineshape control. By exploiting a dual-comb scheme, the optical delay and ...

  7. Magnetic-Driven Winds from Post-AGB Stars: Solutions for High Speed Winds and Extreme Collimation

    CERN Document Server

    García-Segura, G; Franco, J; Garcia-Segura, Guillermo; Lopez, Jose Alberto; Franco, Jose

    2004-01-01

    This paper explores the effects of post-AGB winds driven solely by magnetic pressure from the stellar surface. It is found that winds can reach high speeds under this assumption, and lead to the formation of highly collimated proto-planetary nebulae. Bipolar knotty jets with periodic features and constant velocity are well reproduced by the models. Several wind models with terminal velocities from a few tens of $\\kms$ up to $10^3$ $\\kms$ are calculated, yielding outflows with linear momenta in the range $10^{36}-10^{40} \\gcms$, and kinetic energies in the range $10^{42}-10^{47} $ erg. These results are in accord with recent observations of proto-planetary nebulae that have pointed out serious energy and momentum deficits if radiation pressure is considered as the only driver for these outflows. Our models strengthen the notion that the large mass-loss rates of post-AGB stars, together with the short transition times from the late AGB to the planetary nebula stage, could be directly linked with the generation ...

  8. Extreme wind speeds in mixed climates revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Nicholas J.; Ian Harris, R. [Anemos Associates Ltd., 14 The Chestnuts, Hemel Hempstead HP3 0DZ (United Kingdom); Whiting, Richard [Department of Aerospace, University of Bristol, Bristol BS8 1TR (United Kingdom)

    2003-02-01

    The methodology for the analysis of extreme wind speeds in mixed climates originally proposed in 1978 by Gomes and Vickery is updated to take advantage of recent improvements in methodology and available data records. The revised methodology is demonstrated for two sites in Australia: Onslow and Brisbane. This work shows that the observed curvature in the upper tail is due to incomplete convergence to the Fisher-Tippett Type 1 asymptote and is not an indicator of Type 3 behaviour as sometimes supposed. It is also shown that moving from a reference epoch of 1 year to an epoch of 50 years frees the method from most of the rate-dependent assumptions, and simplifies the problem to a single, dominant wind mechanism.

  9. Climate projection of extreme wind speed regime in the Arctic

    Science.gov (United States)

    Surkova, Galina; Sokolova, Larisa

    2016-04-01

    Extreme surface wind events over the Arctic (60-90N, 0-360 E) are studied for the modern climate and for its future possible changes on the base of ERA-Interim reanalysis data and CMIP5 scenario RCP8.5. Horizontal surface wind speed (10 m) probability distribution functions in every grid point of reanalysis and models data over the Arctic were evaluated as well as wind speed for 50, 95, 99, 99.9 percentiles (V0.50, V0.95, V0.99, V0.999). At first, changes of V0.50, V0.95, V0.99, V0.999 were studied on the base of ERA-Interim reanalysis for 1981-2010. Results showed regional inhomogenity of wind speed trend intensity. Also, analysis was made for zonal means and separate sectors of the Arctic. To study climate projection of high wind speed there were taken u,v values from CMIP5 numerical experiments for 1961-1990 (Historical) and 2081-2100 (RCP8.5). RCP8.5 scenario was chosen as having the most pronounced response in the climate system, which gave more statistical significance to the calculated trends. Modeled extreme wind speeds for the total Arctic and zonal means show rather good agreement with reanalysis data (compared for decades 1981-1990, 1991-2000). At the same time regional intermodel variability of wind speed is revealed. Trend of extreme surface wind speed in 21 century and for 2081-2100 over the Arctic are analyzed for each model. The study was supported by the Russian Science Foundation (project no. 14-37-00038).

  10. Enhanced horizontal extreme-echo speed occurrence leading to polar mesospheric summer echoes (PMSE) increase at solar-wind pressure enhancement during high-speed solar wind stream events

    Science.gov (United States)

    Lee, Y.; Kirkwood, S.; Kwak, Y.; Kim, K.; Shepherd, G. G.

    2013-12-01

    We report on horizontal extreme echo speeds (HEES, ≥ 300 ms^{-1}) observed in long-periodic polar mesospheric summer echoes (PMSE) correlated with solar-wind speed in high speed solar wind streams (HSS) events. The observations were made from VHF 52 MHz radar measurements at Esrange (67.8°N, 20.4°E) between June 1-August 8 in 2006 and 2008. The periodicities of PMSE counts and the volume reflectivity primarily occur at 7, 9 and 13.5 days possibly by the effects of HSS, while the periodicities at 4-6 days are competitively coherent between planetary waves appearing in temperature and solar-wind speed during HSS events. The peaks of both HEES occurrence rate relative to PMSE and turbulence dominantly occur at solar-wind pressure enhancement with minor peaks continued under the passage of HSS over the magnetopause, followed by PMSE peaks in 1-3 days later. This study gives the results that the precipitating high-energetic particles (> 30 keV) during HSS likely induce D-region ionization involved with the consecutive processes of HEES, turbulence and PMSE. The turbulence evolved from the HEES can be explained with the Kelvin-Helmholtz instability, which was observed in PMSE by Röttger et al. [11th International Workshop on technical and scientific aspects of MST Radar, 2006] and firstly simulated for PMSE generation by Hill et al. [Earth Planets Space, 1999]. The HEES is understood as the speed of fast moving ions, accelerated by strong electric field as Lee & Shepherd [JGR, 2010] suggested with the supersonic velocities persisting in polar mesospheric clouds (PMC) region observed at enhanced O(^1S) emission rate ( 10 kR) by WINDII/UARS satellite.

  11. High speed heterostructure devices

    CERN Document Server

    Beer, Albert C; Willardson, R K; Kiehl, Richard A; Sollner, T C L Gerhard

    1994-01-01

    Volume 41 includes an in-depth review of the most important, high-speed switches made with heterojunction technology. This volume is aimed at the graduate student or working researcher who needs a broad overview andan introduction to current literature. Key Features * The first complete review of InP-based HFETs and complementary HFETs, which promise very low power and high speed * Offers a complete, three-chapter review of resonant tunneling * Provides an emphasis on circuits as well as devices.

  12. High-Speed TCP Testing

    Science.gov (United States)

    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.

  13. High Speed Video Insertion

    Science.gov (United States)

    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.

  14. High speed multiphoton imaging

    Science.gov (United States)

    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.

  15. High speed flywheel

    Science.gov (United States)

    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.

  16. HIGH SPEED CAMERA

    Science.gov (United States)

    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.

  17. High-speed AC motors

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, T.; Arkkio, A. [Helsinki University of Technology Laboratory of Electromechanics, Otaniemi (Finland)

    1997-12-31

    The paper deals with various types of highspeed electric motors, and their limiting powers. Standard machines with laminated rotors can be utilised if the speed is moderate. The solid rotor construction makes it possible to reach higher power and speed levels than those of laminated rotors. The development work on high-speed motors done at Helsinki University of Technology is presented, too. (orig.) 12 refs.

  18. Potential of Offshore Wind Energy and Extreme Wind Speed Forecasting on the West Coast of Taiwan

    Directory of Open Access Journals (Sweden)

    Pei-Chi Chang

    2015-02-01

    Full Text Available It is of great importance and urgency for Taiwan to develop offshore wind power. However, relevant data on offshore wind energy resources are limited. This study imported wind speeds measured by a tidal station and a buoy into the software WAsP to estimate the high-altitude wind speeds in the two areas. A light detection and ranging (Lidar system was set up near the tidal station and buoy. High-altitude wind speeds measured by the Lidar system were compared with the WAsP-estimated values, and it was discovered that the two data sets were consistent. Then, long-term wind speed data observed by buoys and tidal stations at various locations were imported into WAsP to forecast wind speeds at heights of 55–200 m on the west coast of Taiwan. The software WAsP Engineering was used to analyze the extreme wind speeds in the same areas. The results show that wind speeds at 100 m are approximately 9.32–11.24 m/s, which means that the coastal areas of west Taiwan are rich in wind energy resources. When a long-term 10-min average wind speed is used, the extreme wind speed on the west coast is estimated to be between 36.4 and 55.3 m/s.

  19. High Speed Compressor Study

    Science.gov (United States)

    2011-12-21

    are listed below, and some of these are discussed at length later. o Heat capacity issues in low temperature regenerators o Pressure drop losses...carried out on a relatively old design of compressor, initially developed for use with a Stirling cycle domestic freezer12, and subsequently used in a...2003), pp 247-253. 3 Wang, X, Dai, W., et al, “Performance of a Stirling -Type Pulse Tube Cooler for High Efficiency Operation at 100Hz

  20. High speed preprocessing system

    Indian Academy of Sciences (India)

    M Sankar Kishore

    2000-10-01

    In systems employing tracking, the area of interest is recognized using a high resolution camera and is handed overto the low resolution receiver. The images seen by the low resolution receiver and by the operator through the high resolution camera are different in spatial resolution. In order to establish the correlation between these two images, the high-resolution camera image needsto be preprocessed and made similar to the low-resolution receiver image. This paper discusses the implementation of a suitable preprocessing technique, emphasis being given to develop a system both in hardware and software to reduce processing time. By applying different software/hardware techniques, the execution time has been brought down from a few seconds to a few milliseconds for a typical set of conditions. The hardware is designed around i486 processors and software is developed in PL/M. The system is tested to match the images obtained by two different sensors of the same scene. The hardware and software have been evaluated with different sets of images.

  1. High speed optical networks

    Science.gov (United States)

    Frankel, Michael Y.; Livas, Jeff

    2005-02-01

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

  2. Performance evaluation of high speed compressors for high speed multipliers

    Directory of Open Access Journals (Sweden)

    Nirlakalla Ravi

    2011-01-01

    Full Text Available This paper describes high speed compressors for high speed parallel multipliers like Booth Multiplier, Wallace Tree Multiplier in Digital Signal Processing (DSP. This paper presents 4-3, 5-3, 6-3 and 7-3 compressors for high speed multiplication. These compressors reduce vertical critical path more rapidly than conventional compressors. A 5-3 conventional compressor can take four steps to reduce bits from 5 to 3, but the proposed 5-3 takes only 2 steps. These compressors are simulated with H-Spice at a temperature of 25°C at a supply voltage 2.0V using 90nm MOSIS technology. The Power, Delay, Power Delay Product (PDP and Energy Delay Product (EDP of the compressors are calculated to analyze the total propagation delay and energy consumption. All the compressors are designed with half adder and full Adders only.

  3. High-speed photonics interconnects

    CERN Document Server

    Chrostowski, Lukas

    2013-01-01

    Dramatic increases in processing power have rapidly scaled on-chip aggregate bandwidths into the Tb/s range. This necessitates a corresponding increase in the amount of data communicated between chips, so as not to limit overall system performance. To meet the increasing demand for interchip communication bandwidth, researchers are investigating the use of high-speed optical interconnect architectures. Unlike their electrical counterparts, optical interconnects offer high bandwidth and negligible frequency-dependent loss, making possible per-channel data rates of more than 10 Gb/s. High-Speed

  4. High-speed pulse techniques

    CERN Document Server

    Coekin, J A

    1975-01-01

    High-Speed Pulse Techniques covers the many aspects of technique in digital electronics and encompass some of the more fundamental factors that apply to all digital systems. The book describes the nature of pulse signals and their deliberate or inadvertent processing in networks, transmission lines and transformers, and then examines the characteristics and transient performance of semiconductor devices and integrated circuits. Some of the problems associated with the assembly of these into viable systems operating at ultra high speed are also looked at. The book examines the transients and w

  5. High-speed OTDM switching

    DEFF Research Database (Denmark)

    Jepsen, Kim Stokholm; Mikkelsen, Benny; Clausen, Anders

    1998-01-01

    Optical TDM (OTDM) continues to be of interest both for point-point transmission and as a networking technology for both LANs and long-distance fibre transmission. Recent research has demonstrated enabling techniques for OTDM networks at high speeds. In conclusion, OTDM is emerging as an attracti...

  6. Relativistic QED Plasma at Extremely High Temperature

    CERN Document Server

    Masood, Samina S

    2016-01-01

    Renormalization scheme of QED (Quantum Electrodynamics) at high temperatures is used to calculate the effective parameters of relativistic plasma in the early universe. Renormalization constants of QED play role of effective parameters of the theory and can be used to determine the collective behavior of the medium. We explicitly show that the dielectric constant, magnetic reluctivity, Debye length and the plasma frequency depend on temperature in the early universe. Propagation speed, refractive index, plasma frequency and Debye shielding length of a QED plasma are computed at extremely high temperatures in the early universe. We also found the favorable conditions for the relativistic plasma from this calculations.

  7. "Extreme events" in STT-MRAM speed retention and reliability (Conference Presentation)

    Science.gov (United States)

    Wang, Xiaobin; Zhang, Jing; Wang, Zihui; Hao, Xiaojie; Zhou, Yuchen; Gan, Huadong; Jun, Dongha; Satoh, Kimihiro; Yen, Bing K.; Huai, Yiming

    2016-10-01

    Fast operation speed, high retention and high reliability are the most attractive features of the spin transfer torque magnetic random access memory (STT-MRAM) based upon perpendicular magnetic tunneling junction (pMTJ). For state-of-the-art pMTJ STT-MRAM, its device performance is fundamentally determined by material "extreme events" physics. For example, nanosecond write bit error rate is determined by extremely high probability (>(1-10^(-7))) stochastic magnetization switching events, retention is determined by magnetization configurations with extremely low switching probability, reliability is determined by extremely low probability (MRAM write, read, retention and reliability. Specifically, we will present our model that accurately calculates extremely low write BER for various magnetization configurations. We will review our study of thermal magnetization switching through the dynamic optimal reversal path approach, capable of characterizing extreme thermal magnetization switching events under both low frequency (e.g. static retention) and high frequency (e.g. fast read) excitations. We will also discuss a new MTJ breakdown reliability model that quantifies extreme events uniformly at different failure mode regions.

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

    Science.gov (United States)

    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

  9. Small Scale High Speed Turbomachinery

    Science.gov (United States)

    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.

  10. Exploring of Chinese High-speed Railways

    Institute of Scientific and Technical Information of China (English)

    liuYoumei

    2004-01-01

    Based ion experiences of high-speed railways in foreign countries,the speed-raise situation of the Chinese railways,the research & development and test of high-speed transportation carries,as well as the prospective of high-speed railway in China are introduced.

  11. Cutting tool materials for high speed machining

    Institute of Scientific and Technical Information of China (English)

    LIU Zhanqiang; AI Xing

    2005-01-01

    High speed machining (HSM) is one of the emerging cutting processes, which is machining at a speed significantlyhigher than the speed commonly in use on the shop floor. In the last twenty years, high speed machining has received great attentions as a technological solution for high productivity in manufacturing. This article reviews the developments of tool materials in high speed machining operations, and the properties, applications and prospective developments of tool materials in HSM are also presented.

  12. Flexible high-speed CODEC

    Science.gov (United States)

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

    1993-08-01

    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.

  13. Towards high-speed scanning tunneling microscopy

    NARCIS (Netherlands)

    Tabak, Femke Chantal

    2013-01-01

    In this thesis, two routes towards high-speed scanning tunneling microscopy (STM) are described. The first possibility for high-speed scanning that is discussed is the use of MEMS (Micro-Electro Mechanical Systems) devices as high-speed add-ons in STM microscopes. The functionality of these devices

  14. High Speed Viterbi Decoder Architecture

    DEFF Research Database (Denmark)

    Paaske, Erik; Andersen, Jakob Dahl

    1998-01-01

    The fastest commercially available Viterbi decoders for the (171,133) standard rate 1/2 code operate with a decoding speed of 40-50 Mbit/s (net data rate). In this paper we present a suitable architecture for decoders operating with decoding speeds of 150-300 Mbit/s.......The fastest commercially available Viterbi decoders for the (171,133) standard rate 1/2 code operate with a decoding speed of 40-50 Mbit/s (net data rate). In this paper we present a suitable architecture for decoders operating with decoding speeds of 150-300 Mbit/s....

  15. Analysis and Modelling of Extreme Wind Speed Distributions in Complex Mountainous Regions

    Science.gov (United States)

    Laib, Mohamed; Kanevski, Mikhail

    2016-04-01

    Modelling of wind speed distributions in complex mountainous regions is an important and challenging problem which interests many scientists from several fields. In the present research, high frequency (10 min) Swiss wind speed monitoring data (IDAWEB service, Meteosuisse) are analysed and modelled with different parametric distributions (Weibull, GEV, Gamma, etc.) using maximum likelihood method. In total, 111 stations placed in different geomorphological units and at different altitude (from 203 to 3580 meters) are studied. Then, this information is used for training machine learning algorithms (Extreme Learning Machines, Support vector machine) to predict the distribution at new places, potentially useful for aeolian energy generation. An important part of the research deals with the construction and application of a high dimensional input feature space, generated from digital elevation model. A comprehensive study was carried out using feature selection approach to get the best model for the prediction. The main results are presented as spatial patterns of distributions' parameters.

  16. Experimental high-speed network

    Science.gov (United States)

    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.

  17. Extreme midlatitude cyclones and their implications for precipitation and wind speed extremes in simulations of the Maunder Minimum versus present day conditions

    Energy Technology Data Exchange (ETDEWEB)

    Raible, C.C.; Casty, C. [University of Bern, Climate and Environmental Physics, Physics Institute, Bern (Switzerland); Yoshimori, M. [University of Bern, Climate and Environmental Physics, Physics Institute, Bern (Switzerland); Rutgers University, Center for Environmental Prediction, New Brunswick, NJ (United States); Stocker, T.F. [University of Bern, Climate and Environmental Physics, Physics Institute, Bern (Switzerland); University of Hawaii, International Pacific Research Center, SOEST, Honolulu, HI (United States)

    2007-03-15

    Extreme midlatitude cyclone characteristics, precipitation, wind speed events, their inter-relationships, and the connection to large-scale atmospheric patterns are investigated in simulations of a prolonged cold period, known as the Maunder Minimum from 1640 to 1715 and compared with today. An ensemble of six simulations for the Maunder Minimum as well as a control simulation for perpetual 1990 conditions are carried out with a coupled atmosphere-ocean general circulation model, i.e., the Climate Community System Model (CCSM). The comparison of the simulations shows that in a climate state colder than today the occurrence of cyclones, the extreme events of precipitation and wind speed shift southward in all seasons in the North Atlantic and the North Pacific. The extremes of cyclone intensity increases significantly in winter in almost all regions, which is related to a stronger meridional temperature gradient and an increase in lower tropospheric baroclinicity. Extremes of cyclone intensity in subregions of the North Atlantic are related to extremes in precipitation and in wind speed during winter. Moreover, extremes of cyclone intensity are also connected to distinct large-scale atmospheric patterns for the different subregions, but these relationships vanish during summer. Analyzing the mean 1,000 hPa geopotential height change of the Maunder Minimum simulations compared with the control simulation, we find a similar pattern as the correlation pattern with the cyclone intensity index of the southern Europe cyclones. This illustrates that changes in the atmospheric high-frequency, i.e., the simulated southward shift of cyclones in the North Atlantic and the related increase of extreme precipitation and wind speed in particular in the Mediterranean in winter, are associated with large-scale atmospheric circulation changes. (orig.)

  18. High speed imaging - An important industrial tool

    Science.gov (United States)

    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.

  19. Comparison of High Speed Congestion Control Protocols

    Directory of Open Access Journals (Sweden)

    Jawhar Ben Abed

    2012-10-01

    Full Text Available Congestion control limits the quantity of information input at a rate less important than that of thetransmission one to ensure good performance as well as protect against overload and blocking of thenetwork. Researchers have done a great deal of work on improving congestion control protocols,especially on high speed networks.In this paper, we will be studying the congestion control alongside low and high speed congestion controlprotocols. We will be also simulating, evaluating, and comparing eight of high speed congestion controlprotocols : Bic TCP, Cubic TCP, Hamilton TCP, HighSpeed TCP, Illinois TCP, Scalable TCP,Compound TCP and YeAH TCP, with multiple flows.

  20. High Speed On-Wafer Characterization Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — At the High Speed On-Wafer Characterization Laboratory, researchers characterize and model devices operating at terahertz (THz) and millimeter-wave frequencies. The...

  1. High Speed On-Wafer Characterization Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — At the High Speed On-Wafer Characterization Laboratory, researchers characterize and model devices operating at terahertz (THz) and millimeter-wave frequencies. The...

  2. High-Speed Ring Bus

    Science.gov (United States)

    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

  3. Predicting extreme wind speeds on a tropical island for multi-peril catastrophe modelling

    Science.gov (United States)

    Thornton, James; Moncoulon, David; Millinship, Ian; Raven, Emma

    2013-04-01

    Catastrophe models are important tools used by the reinsurance industry for assessing and managing risk. Here, we present the methods used to develop high-resolution wind hazard maps for the Indian Ocean island of La Réunion. As the recent Cyclone Dumile (January 2013) reminded us, the island is at considerable risk from the extreme weather associated with tropical cyclones. It also contains a significant proportion of the total value insured in French overseas territories. The wind maps, alongside flood and storm surge maps, were ultimately combined with exposure information in a multi-peril catastrophe model to provide probabilistic estimates of insured loss. Our wind mapping methodology used established extreme value theory statistics to estimate the annual probability of extreme wind speeds, including those exceeding the observed maxima of our 19 year record, at meteorological stations. This gave approximate wind speeds for a range of return periods at these specific locations. Since the spatial density of the stations was insufficient to resolve the numerous potential effects of the complex island topography, geographically weighted regression (GWR) models were then developed to interpolate these cyclonic wind speeds across the entire island. Factors known to affect local wind speed such as elevation, surface roughness and coastal proximity were explicitly accounted for. Using this advanced interpolation method, wind hazard maps were produced for six return periods between 1 in 10 and 1 in 1000 years. Our maps compared favourably with those of historical events, and also showed patterns of wind speed in agreement with the findings of other studies investigating the effects of topography. Leave-one-out cross-validation (LOOCV) further confirmed the satisfactory performance of the models in providing a robust and comprehensive description of wind patterns during cyclone passage. Uncertainty increased with return period as more extrapolation of the limited

  4. Reducing Heating In High-Speed Cinematography

    Science.gov (United States)

    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.

  5. High-speed Stochastic Fatigue Testing

    DEFF Research Database (Denmark)

    Brincker, Rune; Sørensen, John Dalsgaard

    1990-01-01

    Good stochastic fatigue tests are difficult to perform. One of the major reasons is that ordinary servohydraulic loading systems realize the prescribed load history accurately at very low testing speeds only. If the speeds used for constant amplitude testing are applied to stochastic fatigue...... the analog control device remain as the basic control mechanism in the system, but distorting the input signal by computer in order to minimize the errors of the load history extremes. The principle proves to be very efficient to reduce all kinds of system errors and has shown to be able to increase...

  6. Application Of High Speed Photography In Science And Technology

    Science.gov (United States)

    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. Secondary Containment Design for a High Speed Centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, K.W.

    1999-03-01

    Secondary containment for high speed rotating machinery, such as a centrifuge, is extremely important for operating personnel safety. Containment techniques can be very costly, ungainly and time consuming to construct. A novel containment concept is introduced which is fabricated out of modular sections of polycarbonate glazed into a Unistrut metal frame. A containment study for a high speed centrifuge is performed which includes the development of parameters for secondary containment design. The Unistrut/polycarbonate shield framing concept is presented including design details and proof testing procedures. The economical fabrication and modularity of the design indicates a usefulness for this shielding system in a wide variety of containment scenarios.

  8. Active control system for high speed windmills

    Science.gov (United States)

    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.

  9. ERROR CORRECTION IN HIGH SPEED ARITHMETIC,

    Science.gov (United States)

    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)

  10. Damping Bearings In High-Speed Turbomachines

    Science.gov (United States)

    Von Pragenau, George L.

    1994-01-01

    Paper presents comparison of damping bearings with traditional ball, roller, and hydrostatic bearings in high-speed cryogenic turbopumps. Concept of damping bearings described in "Damping Seals and Bearings for a Turbomachine" (MFS-28345).

  11. On China's High-Speed Railway Technology

    Institute of Scientific and Technical Information of China (English)

    You-tong FANG

    2011-01-01

    Energy and environmental issues have become increasingly prominent in matters of transportation.Compared with road,air,and sea transportation,railway transportation has the advantages of a large transmission capacity,with rapid,safe,and on-time travel,requiring less land resources,with lower energy consumption,less environmental pollution,and the capacity to operate under most weather conditions.In particular,high-speed railway technology has been growing rapidly.Since the world's first high-speed railway was built in Japan in 1964,more than ten countries and regions have developed high-speed railways,operating over a total of more than 10000 km.High-speed railways not only provide the public with a new type of rapid,convenient,safe,and comfortable travel,but also greatly boost the socio-economic development of the country.

  12. Switching speed limitations of high power IGBT modules

    DEFF Research Database (Denmark)

    Incau, Bogdan Ioan; Trintis, Ionut; Munk-Nielsen, Stig

    2015-01-01

    In this paper the switching speed limits of high power IGBT modules are investigated. The limitation of turn-on and turn-off switching speeds of the IGBTs are experimentally detected in a pulse tester. Different dc-bus stray inductances are considered, as well as the worst case scenario...... for the blocking dc-link voltage. Switching losses are analyzed upon a considerable variation of resistor value from turn-on gate driver side. Short circuit operations are investigated along with safe operating area for entire module to validate electrical capabilities under extreme conditions....

  13. Flat belt continuously variable high speed drive

    Energy Technology Data Exchange (ETDEWEB)

    Kumm, E.L.

    1992-02-01

    A study was undertaken at Kumm Industries funded by DOE in the NBS/DOE Energy-Related Inventions Program starting in August 1990 to design, construct and test a novel very high speed flat belt drive. The test arrangement as shown in Figure 1 consists of a multiple belt-pulley configuration that transmits power from a low speed (2000--4000 RPM) input to a small pulley turbine'' (27,000 to 55,000 RPM) and then to the low speed output variable radius pulley (2000--5000 RPM) via a special self-active tensioner. Transmitting 25 HP to and from the turbine'' corresponds to obtaining 50 HP in one direction only in a possible turbo compounded engine application. The high speed of the turbine'' belts, i.e. 100 meters/sec. at 55,000 RPM, while transferring substantial power is a new much higher operating regime for belts. The study showed that the available belts gave overall test rig efficiencies somewhat above 80% for the higher speeds (50,000 RPM) and higher powers (corresponding to above 90% in the turbocompound application) and a significantly better efficiencies at slightly lower speeds. The tests revealed a number of improved approaches in the design of such high speed drives. It appears that there is considerable possibility for further improvement and application of such equipment.

  14. Changes in Wind Speed and Extremes in Beijing during 1960-2008 Based on Homogenized Observations

    Institute of Scientific and Technical Information of China (English)

    LI Zhen; YAN Zhongwei; TU Kai; LIU Weidong; WANG Yingchun

    2011-01-01

    Daily observations of wind speed at 12 stations in the Greater Beijing Area during 1960-2008 were homogenized using the Multiple Analysis of Series for Homogenization method. The linear trends in the regional mean annual and seasonal (winter, spring, summer and autumn) wind speed series were -0.26,-0.39, -0.30, -0.12 and -0.22 m s-1 (10 yr)-1, respectively. Winter showed the greatest magnitude in declining wind speed, followed by spring, autumn and summer. The annual and seasonal frequencies of wind speed extremes (days) also decreased, more prominently for winter than for the other seasons. The declining trends in wind speed and extremes were formed mainly by some rapid declines during the 1970s and 1980s. The maximum declining trend in wind speed occurred at Chaoyang (CY), a station within the central business district (CBD) of Beijing with the highest level of urbanization. The declining trends were in general smaller in magnitude away from the city center, except for the winter case in which the maximum declining trend shifted northeastward to rural Miyun (MY). The influence of urbanization on the annual wind speed was estimated to be about -0.05 m s-1 (10 yr)-1 during 1960-2008, accounting for around one fifth of the regional mean declining trend. The annual and seasonal geostrophic wind speeds around Beijing, based on daily mean sea level pressure (MSLP) from the ERA-40 reanalysis dataset, also exhibited decreasing trends, coincident with the results from site observations. A comparative analysis of the MSLP fields between 1966-1975 and 1992-2001 suggested that the influences of both the winter and summer monsoons on Beijing were weaker in the more recent of the two decades. It is suggested that the bulk of wind in Beijing is influenced considerably by urbanization, while changes in strong winds or wind speed extremes are prone to large-scale climate change in the region.

  15. Design of a High Speed Adder

    OpenAIRE

    Aritra Mitra; Amit Bakshi; Bhavesh Sharma; Nilesh Didwania

    2015-01-01

    In this paper we have compared different addition algorithms such as Ripple Carry Adder, Carry Save Adder, Carry Select Adder, Carry Look Ahead Adder & Kogge Stone Adder for different performance parameters i.e. Area Utilization, Speed of operation and Power Consumption. A high speed Adder is then designed by merging Kogge Stone & Carry Select Algorithms. The circuits have been designed using Verilog HDL & Synthesize using TSMC 180 nm standard cell. The performance parameters are ...

  16. Compressibility, turbulence and high speed flow

    CERN Document Server

    Gatski, Thomas B

    2013-01-01

    Compressibility, Turbulence and High Speed Flow introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range, through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. The book provides the reader with the necessary background and current trends in the theoretical and experimental aspects of compressible turbulent flows and compressible turbulence. Detailed derivations of the pertinent equations describing the motion of such turbulent flows is provided and

  17. Mapping of extreme wind speed for landscape modelling of the Bohemian Forest, Czech Republic

    Directory of Open Access Journals (Sweden)

    L. Pop

    2014-01-01

    Full Text Available Extreme wind events are among the most damaging weather-related hazards in the Czech Republic, forestry is heavily affected. In order to successfully run a landscape model dealing with such effects, spatial distribution of extreme wind speed statistics is needed. The presented method suggests using sector-wise wind field calculations together with extreme value statistics fitted at a reference station. A special algorithm is proposed to provide the data in the form expected by the landscape model, i.e. raster data of annual wind speed maxima. The method is demonstrated on the area of Bohemian Forest that represents one of largest and most compact forested mountains in Central Europe. The reference meteorological station Churáňov is located within the selected domain. Numerical calculations were based on linear model of WAsP Engineering methodology. Observations were cleaned of inhomogeneity and classified into convective and non-convective cases using index CAPE. Due to disjunct sampling of synoptic data, appropriate corrections were applied to the observed extremes. Finally they were fitted with Gumbel distribution. The output of numerical simulation is presented for the windiest direction sector. Another map shows probability that annual extreme exceeds required threshold. The method offers a tool for generation of spatially variable annual maxima of wind speed. It assumes a small limited model domain containing a reliable wind measurement. We believe that this is typical setup for applications similar to one presented in the paper.

  18. VLSI Circuits for High Speed Data Conversion

    Science.gov (United States)

    1994-05-16

    Meeting, pp. 289-292, Sept. 199 1. [4] Behzad Razavi , "High-Speed, Nigh-Resolution Analog-to-Digital Conversion in VLSI Technologies, Ph.D. Thesis... Behzad Razavi and Bruce A. Wooley, "Design Techniques for High-Speed, High- Resolution Comparators," IEEE J. Solid-State Circuits, vol. 27, pp. 1916-192...Dec. 1992. [8] Behzad Razavi and Bruce A. Wooley, "A 12-Bkt 5-MSamplesoc Two-Step CMOS A/D Converter," IEEE J. Solid-State Circuits, vol. 27, pp

  19. Lower Extremity Biomechanical Relationships with Different Speeds in Traditional, Minimalist, and Barefoot Footwear

    Directory of Open Access Journals (Sweden)

    William Fredericks, Seth Swank, Madeline Teisberg, Bethany Hampton, Lance Ridpath, Jandy B. Hanna

    2015-06-01

    Full Text Available Minimalist running footwear has grown increasingly popular. Prior studies that have compared lower extremity biomechanics in minimalist running to traditional running conditions are largely limited to a single running velocity. This study compares the effects of running at various speeds on foot strike pattern, stride length, knee angles and ankle angles in traditional, barefoot, and minimalist running conditions. Twenty-six recreational runners (19-46 years of age ran on a treadmill at a range of speeds (2.5-4.0 m·sec-1. Subjects ran with four different footwear conditions: personal, standard, and minimalist shoes and barefoot. 3D coordinates from video data were collected. The relationships between speed, knee and ankle angles at foot strike and toe-off, relative step length, and footwear conditions were evaluated by ANCOVA, with speed as the co-variate. Distribution of non-rearfoot strike was compared across shod conditions with paired t-tests. Non-rearfoot strike distribution was not significantly affected by speed, but was different between shod conditions (p < 0.05. Footwear condition and speed significantly affected ankle angle at touchdown, independent of one another (F [3,71] = 10.28, p < 0.001, with barefoot and minimalist running exhibiting greater plantarflexion at foot strike. When controlling for foot strike style, barefoot and minimalist runners exhibited greater plantarflexion than other conditions (p < 0.05. Ankle angle at lift-off and relative step length exhibited a significant interaction between speed and shod condition. Knee angles had a significant relationship with speed, but not with footwear. There is a clear influence of footwear, but not speed, on foot strike pattern. Additionally, speed and footwear predict ankle angles (greater plantarflexion at foot strike and may have implications for minimalist runners and their risk of injury. Long-term studies utilizing various speeds and habituation times are needed.

  20. Extreme wind speed regime and weather patterns in the Barents Sea

    Science.gov (United States)

    Surkova, Galina; Krylov, Aleksey

    2016-04-01

    The synoptic patterns of extreme wind events over the Barents Sea during 1981-2010 are studied on the base of ERA-Interim reanalysis data (6-hours, 0.75x0.75 degrees of latitude and longitude). Frequency of events was defined after analysis of 50, 95, 99, 99.9 percentiles (V(0.50), V(0.95), V(0.99), V(0.999)) of wind speed probability distribution function over the central part of the sea where wind speed is the highest. First part of the study was devoted to the features of seasonal and interannual variability of the surface (10 m) wind speed. Results showed very slow and statistically almost insignificant decreasing of wind speed for all percentile speed values during 1981-2010. The highest standard deviation for annual percentile speed values were derived for the most seldom events, V(0.999). Mean values for the central part of the Barents Sea are V(0.95)=14.3 m/s, V(0.99)=17.2 m/s, V(0.999)=20.3 m/s. At the next stage the calendar of extreme events with wind speed more the threshold value V(0.99) was extracted. Sea level pressure (SLP) fields for these extreme events were classified by cluster analysis. Formal detection of typical SLP fields accompanying by storm winds allows to evaluate their frequency in different time periods. It is more reliable then use of wind speed data because the accuracy of SLP simulation in re-analysis and climate models is higher than that for the wind speed. The progress of the work is seen as further development of climate projection of extreme events on the base of CMIP5 scenarios through the projection of synoptic situations that create these events as it was shown in our previous works. Developed methodology allows to assess the frequency of synoptic events accompanying by hazards, not only in the past, but in the future. The study was supported by the Russian Science Foundation (project no. 14-37-00038).

  1. Aerodynamics of High-Speed Trains

    Science.gov (United States)

    Schetz, Joseph A.

    This review highlights the differences between the aerodynamics of high-speed trains and other types of transportation vehicles. The emphasis is on modern, high-speed trains, including magnetic levitation (Maglev) trains. Some of the key differences are derived from the fact that trains operate near the ground or a track, have much greater length-to-diameter ratios than other vehicles, pass close to each other and to trackside structures, are more subject to crosswinds, and operate in tunnels with entry and exit events. The coverage includes experimental techniques and results and analytical and numerical methods, concentrating on the most recent information available.

  2. DAC 22 High Speed Civil Transport Model

    Science.gov (United States)

    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.

  3. A high speed digital noise generator

    Science.gov (United States)

    Obrien, J.; Gaffney, B.; Liu, B.

    In testing of digital signal processing hardware, a high speed pseudo-random noise generator is often required to simulate an input noise source to the hardware. This allows the hardware to be exercised in a manner analogous to actual operating conditions. In certain radar and communication environments, a noise generator operating at speeds in excess of 60 MHz may be required. In this paper, a method of generating high speed pseudo-random numbers from an arbitrarily specified distribution (Gaussian, Log-Normal, etc.) using a transformation from a uniform noise source is described. A noise generator operating at 80 MHz has been constructed. Different distributions can be readily obtained by simply changing the ROM set. The hardware and test results will be described. Using this approach, the generation of pseudo-random sequences with arbitrary distributions at word rates in excess of 200 MHz can be readily achieved.

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

    Science.gov (United States)

    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,…

  5. High-Speed Non-Volatile Optical Memory: Achievements and Challenges

    Directory of Open Access Journals (Sweden)

    Vadym Zayets

    2017-01-01

    Full Text Available We have proposed, fabricated, and studied a new design of a high-speed optical non-volatile memory. The recoding mechanism of the proposed memory utilizes a magnetization reversal of a nanomagnet by a spin-polarized photocurrent. It was shown experimentally that the operational speed of this memory may be extremely fast above 1 TBit/s. The challenges to realize both a high-speed recording and a high-speed reading are discussed. The memory is compact, integratable, and compatible with present semiconductor technology. If realized, it will advance data processing and computing technology towards a faster operation speed.

  6. High speed technology development and evaluation

    Science.gov (United States)

    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.

  7. High Speed Wireless Signal Generation and Demodulation

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Sambaraju, Rakesh; Zibar, Darko;

    We present the experimental demonstration of high speed wireless generation, up to 40 Gb/s, in the 75-110 GHz wireless band. All-optical OFDM and photonic up-conversion are used for generation and single side-band modulation with digital coherent detection for demodulation....

  8. High-speed Power Line Communications

    Directory of Open Access Journals (Sweden)

    Matthew N. O. Sadiku,

    2015-11-01

    Full Text Available This is the idea of using existing power lines for communication purposes. Power line communications (PLC enables network communication of voice, data, and video over direct power lines. High-speed PLC involves data rates in excess of 10 Mbps. PLC has attracted a lot of attention and has become an interesting subject of research lately.

  9. High-Speed Rail & Air Transport Competition

    NARCIS (Netherlands)

    Adler, Nicole; Nash, Chris; Pels, Eric

    2008-01-01

    This paper develops a methodology to assess transport infrastructure investments and their effects on a Nash equilibria taking into account competition between multiple privatized transport operator types. The operators, including high-speed rail, hub and spoke legacy airlines and low cost carriers,

  10. High speed adaptive liquid microlens array

    NARCIS (Netherlands)

    Murade, C.U.; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther

    2012-01-01

    Liquid microlenses are attractive for adaptive optics because they offer the potential for both high speed actuation and parallelization into large arrays. Yet, in conventional designs, resonances of the liquid and the complexity of driving mechanisms and/or the device architecture have hampered a

  11. High speed multiplier design using Decomposition Logic

    Directory of Open Access Journals (Sweden)

    Ramanathan Palaniappan

    2009-01-01

    Full Text Available The multiplier forms the core of a Digital Signal Processor and is a major source of power dissipation. Often, the multiplier forms the limiting factor for the maximum speed of operation of a Digital Signal Processor. Due to continuing integrating intensity and the growing needs of portable devices, low-power, high-performance design is of prime importance. A new technique of implementing a multiplier circuit using Decomposition Logic is proposed here which improves speed with very little increase in power dissipation when compared to tree structured Dadda multipliers. Tanner EDA was used for simulation in the TSMC 180nm technology.

  12. High Speed SPM of Functional Materials

    Energy Technology Data Exchange (ETDEWEB)

    Huey, Bryan D. [Univ. of Connecticut, Storrs, CT (United States)

    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.

  13. Sensor study for high speed autonomous operations

    Science.gov (United States)

    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. High speed electrical transmission line design and characterization

    Science.gov (United States)

    Bates, R.; Buttar, C.; Buytaert, J.; Eklund, L.; de Acedo, L. F. S.; Longstaff, I.; Naik, S.; Sullivan, S.; Wraight, K.

    2017-02-01

    High Energy Physics (HEP) experiments have unique requirements for data communication. High data speeds, combined with extreme restrictions on materials allowed, leads to custom transmission lines. This paper will present transmission line design theory, simulation and testing methods. Transmission line designs options like flexes and rigid PCBs as well as cables will be studied. Finite Element Analysis (FEA) software packages simulate energy dissipation and quality of transmitted signals. The characterisation techniques of time-domain reflectometry and frequency-domain measurements are discussed and compared. Bit-error-rate testing is presented and its limitations for design discussed. Methods to improve quality, like three different types of equalization are described.

  15. Lower extremity biomechanical relationships with different speeds in traditional, minimalist, and barefoot footwear.

    Science.gov (United States)

    Fredericks, William; Swank, Seth; Teisberg, Madeline; Hampton, Bethany; Ridpath, Lance; Hanna, Jandy B

    2015-06-01

    Minimalist running footwear has grown increasingly popular. Prior studies that have compared lower extremity biomechanics in minimalist running to traditional running conditions are largely limited to a single running velocity. This study compares the effects of running at various speeds on foot strike pattern, stride length, knee angles and ankle angles in traditional, barefoot, and minimalist running conditions. Twenty-six recreational runners (19-46 years of age) ran on a treadmill at a range of speeds (2.5-4.0 m·sec(-1)). Subjects ran with four different footwear conditions: personal, standard, and minimalist shoes and barefoot. 3D coordinates from video data were collected. The relationships between speed, knee and ankle angles at foot strike and toe-off, relative step length, and footwear conditions were evaluated by ANCOVA, with speed as the co-variate. Distribution of non-rearfoot strike was compared across shod conditions with paired t-tests. Non-rearfoot strike distribution was not significantly affected by speed, but was different between shod conditions (p barefoot and minimalist running exhibiting greater plantarflexion at foot strike. When controlling for foot strike style, barefoot and minimalist runners exhibited greater plantarflexion than other conditions (p barefoot and traditional shoes.Plantarflexion at touchdown does change with speed and with shoe type, with barefoot and minimalist shoes exhibiting a greater plantarflexion angle than traditional running shoes.Knee angles change with speed in all shod conditions, but knee flexion at touchdown is not different between shod conditions.Relative step length changes with speed and shod condition, but there is an interaction between these variables such that step length increases more quickly in traditional shoes as speed increases.

  16. High speed printing with polygon scan heads

    Science.gov (United States)

    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.

  17. Safety issues in high speed machining

    Science.gov (United States)

    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.

  18. High speed, high current pulsed driver circuit

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. High speed sub-micrometric microscopy using optical polymer microlens

    Institute of Scientific and Technical Information of China (English)

    X.H.Zeng; J.Plain; S.Jradi; P.Renaud Goud; R.Deturche; P.Royer; R.Bachelot

    2009-01-01

    We report the high speed scanning submicronic microscopy (SSM) using a low cost polymer microlens integrated at the extremity of an optical fiber.These microlenses are fabricated by a free-radical photopolymerization method.Using a polymer microlens with a radius of curvature of 250 nm,a sub-micrometric gold pattern is imaged experimentally by SSM.Different distances between the tip and the sample are used with a high scanning speed of 200 cm/s.In particular,metallic absorption contrasts are described with an optical spatial resolution of 250 nm at the wavelength of 532 nm.Moreover,finite-difference time-domain (FDTD) simulations concerning the focal lengths of microlenses with different geometries and heights support the experimental data.

  20. Development of a Revolutionary High Speed Spindle

    Science.gov (United States)

    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.

  1. Nanometer lapping technology at high speed

    Institute of Scientific and Technical Information of China (English)

    YANG JianDong; TIAN ChunLin; WANG ChangXing

    2007-01-01

    In floating lapping with solid abrasives, the workpiece is taken as an isolated body. The forces that act on it are analyzed. A differential equation about the forces that act on it is set up, so the forces that act on it and its motion rule are received. Combining it with known lapping tool motion, the relative motion rule between the lapping tool and workpiece is determined too. According to the relative motion, the distribution of abrasives density is designed reasonably, which makes the lapping tool wear uniformly, which, in turn, avoids redressing the lapping tool, saves abrasives, and increases machining accuracy. Combining it with advantages in high speed lapping with solid abrasives, the low cost, high efficiency nanometer lapping at high speed is realized.

  2. Nanometer lapping technology at high speed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In floating lapping with solid abrasives, the workpiece is taken as an isolated body. The forces that act on it are analyzed. A differential equation about the forces that act on it is set up, so the forces that act on it and its motion rule are received. Combining it with known lapping tool motion, the relative motion rule between the lapping tool and workpiece is determined too. According to the relative motion, the distribution of abrasives density is designed reasonably, which makes the lapping tool wear uniformly, which, in turn, avoids redressing the lapping tool, saves abra-sives, and increases machining accuracy. Combining it with advantages in high speed lapping with solid abrasives, the low cost, high efficiency nanometer lapping at high speed is realized.

  3. Flow Characteristics at the Pump-Turbine Interface of a Torque Converter at Extreme Speed Ratios

    Directory of Open Access Journals (Sweden)

    A. Habsieger

    2003-01-01

    Full Text Available The average velocity field at the pump–turbine interface in a scaled version of a truck torque converter was studied. Seven different turbine-to-pump rotational-speed ratios were examined, ranging from near stall (0.065 to overspeed (1.050 so as to determine the effect of the speed ratio on the flow field and on the mass flow rate. Laser velocimetry was used to measure the flow velocity through the pump's exit and the turbine's inlet plane. At the pump's exit, as the speed ratio increases, the high velocities move to the pressure-shell corner and then to both the core-suction and the pressureshell corners. Concentrated velocity gradients are largest at the lowest speed ratio, but areas of velocity gradients are largest near the coupling point. Near the coupling point, the flow field is most nonuniform, which yields a highly periodic flow into the turbine inlet. Above the coupling point, the high velocity remains in the pressure-shell corner but separation is seen to develop at the highest speed ratio. At the turbine's inlet, reverse flow is seen at low speed ratios and is an indicator of flow leakage through the core. Velocity gradients are very large at low speed ratios. As the speed ratio increases to the coupling point, the high velocities remain on the shell side. Above the coupling point, the high-velocity flow migrates from the shell side to the core side. The mass flow rate decreases significantly and nonlinearly with the increase of the speed ratio, but for speed ratios greater than 1.000, the negative slope decreases.

  4. CMOS Image Sensors for High Speed Applications

    Directory of Open Access Journals (Sweden)

    M. Jamal Deen

    2009-01-01

    Full Text Available 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.

  5. CMOS Image Sensors for High Speed Applications.

    Science.gov (United States)

    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).

  6. High-speed tensile test instrument.

    Science.gov (United States)

    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.

  7. High speed functional magnetic resonance imaging

    CERN Document Server

    Gibson, A M

    2002-01-01

    The work in this thesis has been undertaken by the except where indicated by reference, within the Magnetic Resonance Centre at the University of Nottingham during the period from October 1998 to October 2001. This thesis documents the implementation and application of a novel high-speed imaging technique, the multi-slice, echo shifted, echo planar imaging technique. This was implemented on the Nottingham 3 T imaging system, for functional magnetic resonance imaging. The technique uses echo shifting over the slices in a multi-slice echo planar imaging acquisition scheme, making the echo time longer than the repetition time per slice. This allows for rapid volumar sampling of the blood oxygen level dependent effect in the human brain. The new high-speed technique was used to investigate the variability of measuring the timing differences between haemodynamic responses, at the same cortical location, to simple cued motor tasks. The technique was also used in an investigation into motor cortex functional connect...

  8. High-speed massively parallel scanning

    Science.gov (United States)

    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.

  9. The Aerodynamics of High Speed Aerial Weapons

    OpenAIRE

    Prince, Simon A.

    1999-01-01

    The focus of this work is the investigation of the complex compressible flow phenomena associated with high speed aerial weapons. A three dimen- sional multiblock finite volume flow solver was developed with the aim of studying the aerodynamics of missile configurations and their component structures. The first component of the study involved the aerodynamic investigation of the isolated components used in the design of conventional missile config- urations. The computati...

  10. A High-Speed Information Retrieval System

    Institute of Scientific and Technical Information of China (English)

    SHI Shu-dong; LI Zhi-tang

    2004-01-01

    We cleveloped a high-speed information retrieval system. The system hased on the IXP 2800 is one of the dedicute device. The velocily of the information retrieval is 6.8 Gb/s. The protocol support Telnet, FTP, SMTP, POP3 etc. various networks protocols. The information retrieval supports the key word and the natural language process. This paper explains the hardware system, software system and the index of the performance.

  11. Network Based High Speed Product Innovation

    DEFF Research Database (Denmark)

    Lindgren, Peter

    In the first decade of the 21st century, New Product Development has undergone major changes in the way NPD is managed and organised. This is due to changes in technology, market demands, and in the competencies of companies. As a result NPD organised in different forms of networks is predicted...... to be of ever-increasing importance to many different kinds of companies. This happens at the same times as the share of new products of total turnover and earnings is increasing at unprecedented speed in many firms and industries. The latter results in the need for very fast innovation and product development...... - a need that can almost only be resolved by organising NPD in some form of network configuration. The work of Peter Lindgren is on several aspects of network based high speed product innovation and contributes to a descriptive understanding of this phenomenon as well as with normative theory on how NPD...

  12. High-Speed Propeller for Aircraft

    Science.gov (United States)

    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.

  13. Initial performance of the High Speed Photometer

    Science.gov (United States)

    Richards, Evan; Percival, Jeff; Nelson, Matt; Hatter, ED; Fitch, John; White, Rick

    1991-01-01

    The Hubble Space Telescope High Speed Photometer has four image dissector tubes, two with UV sensitive photocathodes, two sensitive to the near UV and to visual light, and a single red sensitive photomultiplier tube. The HSP is capable of photometric measurements from 1200 to 7500 A with time resolution of 11 microseconds and has no moving parts. An initial analysis of the on-orbit engineering performance of the HSP is presented with changes in operating procedures resulting from the primary mirror spherical aberration and experience gained during the verification period.

  14. High Speed Solid State Circuit Breaker

    Science.gov (United States)

    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.

  15. Accident Safety Design for High Speed Elevator

    Directory of Open Access Journals (Sweden)

    Tawiwat Veeraklaew

    2012-12-01

    Full Text Available There have been many elevators exist in buildings for such a long time; however, an accident might happen as a free fall due to lacks of maintenance or some other accident such as firing. Although this situation is rarely occurred, many people are still concerned about it. The question here is how to make passengers to feel safe and confident when they are using an elevator, especially, high speed elevator. This problem is studied here in this paper as a free fall spring-mass-damper system with the stiffness and damping coefficient can be computed as minimum jerk of the system with given constraints on trajectories.

  16. Extreme Transients in the High Energy Universe

    Science.gov (United States)

    Kouveliotou, Chryssa

    2013-01-01

    The High Energy Universe is rich in diverse populations of objects spanning the entire cosmological (time)scale, from our own present-day Milky Way to the re-ionization epoch. Several of these are associated with extreme conditions irreproducible in laboratories on Earth. Their study thus sheds light on the behavior of matter under extreme conditions, such as super-strong magnetic fields (in excess of 10^14 G), high gravitational potentials (e.g., Super Massive Black Holes), very energetic collimated explosions resulting in relativistic jet flows (e.g., Gamma Ray Bursts, exceeding 10^53 ergs). In the last thirty years, my work has been mostly focused on two apparently different but potentially linked populations of such transients: magnetars (highly magnetized neutron stars) and Gamma Ray Bursts (strongly beamed emission from relativistic jets), two populations that constitute unique astrophysical laboratories, while also giving us the tools to probe matter conditions in the Universe to redshifts beyond z=10, when the first stars and galaxies were assembled. I did not make this journey alone I have either led or participated in several international collaborations studying these phenomena in multi-wavelength observations; solitary perfection is not sufficient anymore in the world of High Energy Astrophysics. I will describe this journey, present crucial observational breakthroughs, discuss key results and muse on the future of this field.

  17. Extremely high frequency RF effects on electronics.

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  18. High Speed Telescopic Imaging of Sprites

    Science.gov (United States)

    McHarg, M. G.; Stenbaek-Nielsen, H. C.; Kanmae, T.; Haaland, R. K.

    2010-12-01

    A total of 21 sprite events were recorded at Langmuir Laboratory, New Mexico, during the nights of 14 and 15 July 2010 with a 500 mm focal length Takahashi Sky 90 telescope. The camera used was a Phantom 7.3 with a VideoScope image intensifier. The images were 512x256 pixels for a field of view of 1.3x0.6 degrees. The data were recorded at 16,000 frames per second (62 μs between images) and an integration time of 20 μs per image. Co-aligned with the telescope was a second similar high-speed camera, but with an 85 mm Nikon lens; this camera recorded at 10,000 frames per second with 100 μs exposure. The image format was also 512x256 pixels for a field of view of 7.3x3.7 degrees. The 21 events recorded include all basic sprite elements: Elve, sprite halos, C-sprites, carrot sprites, and large jellyfish sprites. We compare and contrast the spatial details seen in the different types of sprites, including streamer head size and the number of streamers subsequent to streamer head splitting. Telescopic high speed image of streamer tip splitting in sprites recorded at 07:06:09 UT on 15 July 2010.

  19. Extremely compliant and highly stretchable patterned graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Shuze; Huang, Yinjun; Li, Teng, E-mail: LiT@umd.edu [Department of Mechanical Engineering and Maryland NanoCenter, University of Maryland, College Park, Maryland 20742 (United States)

    2014-04-28

    Graphene is intrinsically ultra-stiff in its plane. Its huge mechanical mismatch when interfacing with ultra-compliant biological tissues and elastomers (7–9 orders of magnitude difference in stiffness) poses significant challenge in its application to functional devices such as epidermal electronics and sensing prosthesis. We offer a feasible and promising solution to this significant challenge by suitably patterning graphene into a nanomesh. Through systematic coarse-grained simulations, we show that graphene nanomesh can be made extremely compliant with nearly zero stiffness up to about 20% elongation and then remain highly compliant up to about 50% elongation.

  20. Solidification at the High and Low Rate Extreme

    Energy Technology Data Exchange (ETDEWEB)

    Meco, Halim [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    The microstructures formed upon solidification are strongly influenced by the imposed growth rates on an alloy system. Depending on the characteristics of the solidification process, a wide range of growth rates is accessible. The prevailing solidification mechanisms, and thus the final microstructure of the alloy, are governed by these imposed growth rates. At the high rate extreme, for instance, one can have access to novel microstructures that are unattainable at low growth rates. While the low growth rates can be utilized for the study of the intrinsic growth behavior of a certain phase growing from the melt. Although the length scales associated with certain processes, such as capillarity, and the diffusion of heat and solute, are different at low and high rate extremes, the phenomena that govern the selection of a certain microstructural length scale or a growth mode are the same. Consequently, one can analyze the solidification phenomena at both high and low rates by using the same governing principles. In this study, we examined the microstructural control at both low and high extremes. For the high rate extreme, the formation of crystalline products and factors that control the microstructure during rapid solidification by free-jet melt spinning are examined in Fe-Si-B system. Particular attention was given to the behavior of the melt pool at different quench-wheel speeds. Since the solidification process takes place within the melt-pool that forms on the rotating quench-wheel, we examined the influence of melt-pool dynamics on nucleation and growth of crystalline solidification products and glass formation. High-speed imaging of the melt-pool, analysis of ribbon microstructure, and measurement of ribbon geometry and surface character all indicate upper and lower limits for melt-spinning rates for which nucleation can be avoided, and fully amorphous ribbons can be achieved. Comparison of the relevant time scales reveals that surface-controlled melt

  1. High-Speed RaPToRS

    Science.gov (United States)

    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.

  2. High-speed ACR/NEMA interface

    Science.gov (United States)

    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.

  3. High Speed Fibre Optic Backbone LAN

    Science.gov (United States)

    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.

  4. High Speed Magnetostrictive MEMS Actuated Mirror Deflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main goal of this proposal is to develop high speed magnetostrictive and MEMS actuators for rapidly deflecting or deforming mirrors. High speed, light-weight,...

  5. High Speed Magnetostrictive MEMS Actuated Mirror Deflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop high speed magnetostrictive and MEMS actuators for rapidly deflecting or deforming mirrors. High speed, light-weight, low voltage beam...

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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…

  8. HIGH SPEED INJECTION MOLDING OF HIGH DENSITY POLYETHYLENE - EFFECTS OF INJECTION SPEED ON STRUCTURE AND PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    Kun Jiang; Feng Chen; Qiang Fu; Fei-long Yu; Run Su; Jing-hui Yang; Tian-nan Zhou; Jian Gao; Hua Deng; Ke Wang; Qin Zhang

    2011-01-01

    Thin wall samples of high density polyethylene (HDPE) were prepared via injection molding with differentinjection speeds ranging from 100 mm/s to 1200 mm/s. A significant decrease in the tensile strength and Young's moduluswas observed with increasing injection speed. In order to investigate the mechanism behind this decrease, the orientation,molecular weight, molecular weight distribution, melt flow rate, crystallinity and crystal morphology of HDPE werecharacterized using two-dimensional wide-angle X-ray diffraction (2D-WAXD), gel permeation chromatography (GPC),capillary rheometry and differential scanning calorimetry (DSC), respectively. It is demonstrated that the orientation,molecular weight, molecular weight distribution, melt flow rate and crystallinity have no obvious change with increasinginjection speed. Nevertheless, the content of extended chain crystals or large folded chain crystals was found to decreasewith increasing injection speed. Therefore, it is concluded that the decrease in tensile properties is mainly contributed by the reduced content of extended chain crystals or large folded chain crystals. This study provides industry with valuableinformation for the application of high speed injection molding.

  9. Design of A Novel High Speed Dynamic Comparator with Low Power Dissipation for High Speed ADCs

    Directory of Open Access Journals (Sweden)

    Sougata Ghosh

    2013-01-01

    Full Text Available A new CMOS dynamic comparator using dual input single output differential amplifier as latch stage suitable for high speed analog-to-digital converters with High Speed, low power dissipation and immune to noise than the previous reported work is proposed. Back to-back inverter in the latch stage is replaced with dual-input single output differential amplifier. This topology completely removes the noise that is present in the input. The structure shows lower power dissipation and higher speed than the conventional comparators. The circuit is simulated with 1V DC supply voltage and 250 MHz clock frequency. The proposed topology is based on two cross coupled differential pairs positive feedback and switchable current sources, has a lower power dissipation, higher speed, less area, and it is shown to be very robust against transistor mismatch, noise immunity. Previous reported comparators are designed and simulated their DC response and Transient response in Cadence®Virtuoso Analog Design Environment using GPDK 90nm technology. Layouts of the proposed comparator have been done in Cadence® Virtuoso Layout XL Design Environment. DRC and LVS has been checked and compared with the corresponding circuits and RC extracted diagram has been generated. After that post layout simulation with 1V supply voltage has been done and compared the speed, power dissipation, Area, delay with the results before layout and the superior features of the proposed comparator are established

  10. Neutron and high speed photogrammetric arcjet diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Merging of high speed argon plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Case, A.; Messer, S.; Brockington, S.; Wu, L.; Witherspoon, F. D. [HyperV Technologies Corp., Chantilly, Virginia 22180 (United States); Elton, R. [University of Maryland, College Park, Maryland 20742 (United States)

    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.

  12. HIGH SPEED KERR CELL FRAMING CAMERA

    Science.gov (United States)

    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)

  13. High Speed Water Sterilization Using One-Dimensional Nanostructures

    KAUST Repository

    Schoen, David T.

    2010-09-08

    The removal of bacteria and other organisms from water is an extremely important process, not only for drinking and sanitation but also industrially as biofouling is a commonplace and serious problem. We here present a textile based multiscale device for the high speed electrical sterilization of water using silver nanowires, carbon nanotubes, and cotton. This approach, which combines several materials spanning three very different length scales with simple dying based fabrication, makes a gravity fed device operating at 100000 L/(h m2) which can inactivate >98% of bacteria with only several seconds of total incubation time. This excellent performance is enabled by the use of an electrical mechanism rather than size exclusion, while the very high surface area of the device coupled with large electric field concentrations near the silver nanowire tips allows for effective bacterial inactivation. © 2010 American Chemical Society.

  14. Extreme Precipitation and High-Impact Landslides

    Science.gov (United States)

    Kirschbaum, Dalia; Adler, Robert; Huffman, George; Peters-Lidard, Christa

    2012-01-01

    It is well known that extreme or prolonged rainfall is the dominant trigger of landslides; however, there remain large uncertainties in characterizing the distribution of these hazards and meteorological triggers at the global scale. Researchers have evaluated the spatiotemporal distribution of extreme rainfall and landslides at local and regional scale primarily using in situ data, yet few studies have mapped rainfall-triggered landslide distribution globally due to the dearth of landslide data and consistent precipitation information. This research uses a newly developed Global Landslide Catalog (GLC) and a 13-year satellite-based precipitation record from Tropical Rainfall Measuring Mission (TRMM) data. For the first time, these two unique products provide the foundation to quantitatively evaluate the co-occurence of precipitation and rainfall-triggered landslides globally. The GLC, available from 2007 to the present, contains information on reported rainfall-triggered landslide events around the world using online media reports, disaster databases, etc. When evaluating this database, we observed that 2010 had a large number of high-impact landslide events relative to previous years. This study considers how variations in extreme and prolonged satellite-based rainfall are related to the distribution of landslides over the same time scales for three active landslide areas: Central America, the Himalayan Arc, and central-eastern China. Several test statistics confirm that TRMM rainfall generally scales with the observed increase in landslide reports and fatal events for 2010 and previous years over each region. These findings suggest that the co-occurrence of satellite precipitation and landslide reports may serve as a valuable indicator for characterizing the spatiotemporal distribution of landslide-prone areas in order to establish a global rainfall-triggered landslide climatology. This research also considers the sources for this extreme rainfall, citing

  15. High-Speed Low-Jitter Frequency Multiplication in CMOS

    NARCIS (Netherlands)

    van de Beek, R.C.H.

    2004-01-01

    This thesis deals with high-speed Clock and Frequency Multiplication. The term `high-speedù applies to both the output and the reference frequency of the multiplier. Much emphasis is placed on analysis and optimization of the total timing inaccuracies, and on implementing a high-speed feedback

  16. Photodetector having high speed and sensitivity

    Science.gov (United States)

    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.

  17. High Speed/ Low Effluent Process for Ethanol

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. VLSI circuits for high speed data conversion

    Science.gov (United States)

    Wooley, Bruce A.

    1994-05-01

    The focus of research has been the study of fundamental issues in the design and testing of data conversion interfaces for high performance VLSI signal processing and communications systems. Because of the increased speed and density that accompany the continuing scaling of VLSI technologies, digital means of processing, communicating, and storing information are rapidly displacing their analog counterparts across a broadening spectrum of applications. In such systems, the limitations on system performance generally occur at the interfaces between the digital representation of information and the analog environment in which the system is embedded. Specific results of this research include the design and implementation of low-power BiCMOS comparators and sample-and-hold amplifiers operating at clock rates as high as 200 MHz, the design and integration of a 12-bit, 5 MHz CMOS A/D converter employing a two-step architecture and a novel self-calibrating comparator, the design and integration of an optoelectronic communications receiver front-end in a GaAs-on-Si technology, the initiation of research into the use of an active silicon substrate probe card for fully testing high-performance mixed-signal circuits at the wafer level, and a preliminary study of means for correcting dynamic errors in high-performance A/D converters.

  19. Sensor network architecture for intelligent high-speed train on-board monitoring

    Institute of Scientific and Technical Information of China (English)

    Xiao-fan WU; Chun CHEN; Jia-jun BU; Gang CHEN

    2011-01-01

    The China's high-speed railway is experiencing a rapid growth.Its operating mileage and the number of operating trains will exceed 45000 km and 1500 trains by 2015,respectively.During the long range and constant high-speed operation,the high-speed trains have extremely complex and varied work conditions.Such a situation creates a huge demand for high-speed train on-board monitoring.In this paper,architecture for high-speed train on-board monitoring sensor network is proposed.This architecture is designed to achieve the goals of reliable sensing,scalable data transporting,and easy management.The three design goals are realized separately.The reliable sensing is achieved by deploying redundant sensor nodes in the same components.Then a hierarchal transporting scheme is involved to meet the second goal.Finally,an electronic-tag based addressing method is introduced to solve the management problem.

  20. Optical characterization of high speed microscanners based on static slit profiling method

    Science.gov (United States)

    Alaa Elhady, A.; Sabry, Yasser M.; Khalil, Diaa

    2017-01-01

    Optical characterization of high-speed microscanners is a challenging task that usually requires special high speed, extremely expensive camera systems. This paper presents a novel simple method to characterize the scanned beam spot profile and size in high-speed optical scanners under operation. It allows measuring the beam profile and the spot sizes at different scanning angles. The method is analyzed theoretically and applied experimentally on the characterization of a Micro Electro Mechanical MEMS scanner operating at 2.6 kHz. The variation of the spot size versus the scanning angle, up to ±15°, is extracted and the dynamic bending curvature effect of the micromirror is predicted.

  1. High-tech maintenance for high-speed trains

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Javier Rutz [Nertus Mantenimiento Ferroviario, S.A., Madrid (Spain); Hofmann, Manfred [Siemens AG, Erlangen (Germany). Mobility Div., Integrated Services

    2011-03-15

    Reliable, punctual trains cannot do without professional maintenance. Nertus S.A., a joint subsidiary of Siemens and Renfe, is responsible for providing precisely this for the Spanish high-speed train, Velaro E (AVE S103), which operates between Madrid and Barcelona. (orig.)

  2. High-Speed Smart Camera with High Resolution

    Directory of Open Access Journals (Sweden)

    J. Dubois

    2007-02-01

    Full Text Available High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs, readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded processing. Two types of algorithms have been implemented. A compression algorithm, specific to high-speed imaging constraints, has been implemented. This implementation allows to reduce the large data flow (6.55 Gbps and to propose a transfer on a serial output link (USB 2.0. The second type of algorithm is dedicated to feature extraction such as edge detection, markers extraction, or image analysis, wavelet analysis, and object tracking. These image processing algorithms have been implemented into an FPGA embedded inside the camera. These implementations are low-cost in terms of hardware resources. This FPGA technology allows us to process in real time 500 images per second with a 1280×1024 resolution. This camera system is a reconfigurable platform, other image processing algorithms can be implemented.

  3. High-Speed Smart Camera with High Resolution

    Directory of Open Access Journals (Sweden)

    Mosqueron R

    2007-01-01

    Full Text Available High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs, readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded processing. Two types of algorithms have been implemented. A compression algorithm, specific to high-speed imaging constraints, has been implemented. This implementation allows to reduce the large data flow (6.55 Gbps and to propose a transfer on a serial output link (USB 2.0. The second type of algorithm is dedicated to feature extraction such as edge detection, markers extraction, or image analysis, wavelet analysis, and object tracking. These image processing algorithms have been implemented into an FPGA embedded inside the camera. These implementations are low-cost in terms of hardware resources. This FPGA technology allows us to process in real time 500 images per second with a 1280×1024 resolution. This camera system is a reconfigurable platform, other image processing algorithms can be implemented.

  4. High-temperature MAS-NMR at high spinning speeds.

    Science.gov (United States)

    Kirchhain, Holger; Holzinger, Julian; Mainka, Adrian; Spörhase, Andreas; Venkatachalam, Sabarinathan; Wixforth, Achim; van Wüllen, Leo

    2016-09-01

    A low cost version to enable high temperature MAS NMR experiments at temperatures of up to 700°C and spinning speeds of up to 10kHz is presented. The method relies on inductive heating using a metal coated rotor insert. The metal coating is accomplished via a two step process involving physical vapor deposition and galvanization.

  5. Material constraints on high-speed design

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Taveniku, Mikael

    2013-01-01

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

  7. High Speed, Low Weight Momentum/Reaction Wheels

    OpenAIRE

    1999-01-01

    Advancements in several critical areas have made possible lightweight, strong and highly reliable momentum / reaction wheels. The development of reliable bearings with design features that allow high speed operation for space flight applications has significantly altered the weight / speed / wheel design considerations. Current designs typically operate at speeds at or below 6,000 RPM The new retainerless can achieve speeds 10 times that and meet or improve all other significant bearing opera...

  8. Hybrid Short Term Wind Speed Forecasting Using Variational Mode Decomposition and a Weighted Regularized Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Nantian Huang

    2016-11-01

    Full Text Available Accurate wind speed forecasting is a fundamental element of wind power prediction. Thus, a new hybrid wind speed forecasting model, using variational mode decomposition (VMD, the partial autocorrelation function (PACF, and weighted regularized extreme learning machine (WRELM, is proposed to improve the accuracy of wind speed forecasting. First, the historic wind speed time series is decomposed into several intrinsic mode functions (IMFs. Second, the partial correlation of each IMF sequence is analyzed using PACF to select the optimal subfeature set for particular predictors of each IMF. Then, the predictors of each IMF are constructed in order to enhance its strength using WRELM. Finally, wind speed is obtained by adding up all the predictors. The experiment, using real wind speed data, verified the effectiveness and advancement of the new approach.

  9. Modeling of high-speed electronic devices

    Directory of Open Access Journals (Sweden)

    V. G. Kudrya

    2013-09-01

    Full Text Available Introduction. The theme of this publication is the modeling of electronic tools that operate in the frequency range from zero to terahertz and higher. Application of new concepts and technologies, including biotechnology and nanotechnology in the development of monolithic integrated circuits led to a backlog of technologies of projecting from technologies and experimental research and manufacturing. The aim of this work is to develop algorithms for analysis, reflecting not only topological as well as morphological properties of the object, that is designing within the framework of accounting EMI communicational  transmission of energy and information in the volume of the monolithic integrated circuit. Basic steps for constructing the algorithm. The object of design is presented in the form of basic elements, which can be combined with a communication structure. The object of design is presented in the form of basic elements, which can be combined with a communication structure. There are three types of matrix equations: component; component - communication structure; communication structure. Systems of equations are reduced to standardized descriptors of mathematical model by which to understand current of poles and voltage arcs whole set of basic elements. In this way obtained mathematical model that can be implemented in CAD nano and micro technology electronics. Conclusions. Mathematical models of analysis of high-speed digital and analog electronic means. The algorithm allows morphological optimization is to minimize the adverse effects outside the system of electromagnetic interaction between the components and communicator.

  10. Enhanced high-speed coherent diffraction imaging

    Science.gov (United States)

    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 image matching with coaxial holographic optical correlator

    Science.gov (United States)

    Ikeda, Kanami; Watanabe, Eriko

    2016-09-01

    A computation speed of more than 100 Gbps is experimentally demonstrated using our developed ultrahigh-speed optical correlator. To verify this high computation speed practically, the computation speeds of our optical correlator and conventional digital image matching are quantitatively compared. We use a population count function that achieves the fastest calculation speed when calculating binary matching by a central processing unit (CPU). The calculation speed of the optical correlator is dramatically faster than that using a CPU (2.40 GHz × 4) and 16 GB of random access memory, especially when the calculation data are large-scale.

  12. High Speed Dynamics in Brittle Materials

    Science.gov (United States)

    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

  13. Experimental determination of the critical welding speed in high speed MAG welding

    Institute of Scientific and Technical Information of China (English)

    Hu Zhikun; Wu Chuansong

    2008-01-01

    In high speed MAG welding process, some weld formation defects may be encountered. To get good weld quality, the critical welding speed beyond which humping or undercutting weld bead can occur must be known for different conditions. In this research, high speed MAG welding tests were carried out to check out the effects of different factors on the critical welding speed. Through observing the weld bead profiles and the macrographs of the transverse sections of MAG welds, the occurrence tendency of humping weld was analyzed, and the values of critical welding speed were determined under different levels of welding current or voltage, and the effect of shielding gas compositions on the critical welding speed was also investigated.

  14. 622 Mbps High-speed satellite communication system for WINDS

    Science.gov (United States)

    Ogawa, Yasuo; Hashimoto, Yukio; Yoshimura, Naoko; Suzuki, Ryutaro; Gedney, Richard T.; Dollard, Mike

    2006-07-01

    WINDS is the experimental communications satellite currently under joint development by Japanese Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). The high-speed satellite communication system is very effective for quick deployment of high-speed networks economically. The WINDS will realize ultra high-speed networking and demonstrate operability of satellite communication systems in high-speed internet. NICT is now developing high-speed satellite communication system for WINDS. High-speed TDMA burst modem with high performance TPC error correction is underdevelopment. Up to the DAC on the transmitter and from the ADC on the receiver, all modem functions are performed in the digital processing technology. Burst modem has been designed for a user data rate up to 1244 Mbps. NICT is developing the digital terminal as a user interface and a network controller for this earth station. High compatibility with the Internet will be provided.

  15. High Speed Link Radiated Emission Reduction

    Science.gov (United States)

    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

  16. Extreme Environment High Temperature Communication Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to develop and demonstrate a communications system capable of operation at extreme temperatures and pressures in hostile and corrosive...

  17. 33 CFR 84.24 - High-speed craft.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 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...

  18. Chicago-St. Louis high speed rail plan

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. High Speed Switching Micoplasma in High Pressure Gases

    Science.gov (United States)

    Wakim, Dani; Staack, David

    2012-10-01

    Micro-plasma discharges with switching times approaching 1 ns are studied at pressures from 1 to 16 atm. Applications of these devices are robust high speed switching transistors able to withstand electric interference, high temperatures and harsh environments. Measured discharge conditions at 250 psia in Nitrogen are: gas temperature 2900 K, discharge diameter ˜7 μm and electron density ˜10^17 cm-3. High speed switching is achieved by taking advantage of rapid dynamics of instabilities at high pressure and high electron density. The capacitance and inductance of the circuit also significantly affect transients. Tradeoffs are observed in switching times. By reducing capacitances from 10 pF to ˜1pF attainment of steady state conditions can be reduced from 1 us to ˜ 20 ns. However current rise times increase from 1 ns at high capacitance to 20 ns at low capacitance. A decrease in switching time with increased pressure is also observed. Also investigated are configurations with a third electrode acting as a gate or trigger and various high temperature (>2000K) materials such as platinum rhodium alloys and ceria stabilized zirconia ceramics for device fabrication.

  20. High-speed cinematography of muscle contraction.

    Science.gov (United States)

    HAUPT, R E; WALL, D M

    1962-07-13

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

  1. High Speed and Wide Bandwidth Delta-Sigma ADCs

    NARCIS (Netherlands)

    Bolatkale, M.

    2013-01-01

    This thesis describes the theory, design and implementation of a high-speed, high-performance continuous-time delta-sigma (CTΔΣ) ADC for applications such as medical imaging, high-definition video processing, and wireline and wireless communications. In order to achieve a GHz clocking speed, this

  2. High Speed and Wide Bandwidth Delta-Sigma ADCs

    NARCIS (Netherlands)

    Bolatkale, M.

    2013-01-01

    This thesis describes the theory, design and implementation of a high-speed, high-performance continuous-time delta-sigma (CTΔΣ) ADC for applications such as medical imaging, high-definition video processing, and wireline and wireless communications. In order to achieve a GHz clocking speed, this th

  3. Installation position determination of wind speed sensors on steel pole along a high-speed railway

    Institute of Scientific and Technical Information of China (English)

    熊小慧; 梁习锋

    2016-01-01

    In order to consider the influence of steel pole on the measurement of wind speed sensors and determinate the installation position of wind speed sensors, the flow field around wind speed sensors was investigated. Based on the three-dimensional steady Reynolds-averaged Navier-Stokes equations andk-ε double equations turbulent model, the field flow around the wind speed sensor and the steel pole along a high-speed railway was simulated on an unstructured grid. The grid-independent validation was conducted and the accuracy of the present numerical simulation method was validated by experiments and simulations carried out by previous researchers. Results show that the steel pole has a significant influence on the measurement results of wind speed sensors. As the distance between two wind speed sensors is varied from 0.3 to 1.0 m, the impact angles are less than ±20°, it is proposed that the distance between two wind speed sensors is 0.8 m at least, and the interval between wind speed sensors and the steel pole is more than 1.0 m with the sensors located on the upstream side.

  4. Time optimal paths for high speed maneuvering

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Does dance-based therapy increase gait speed in older adults with chronic lower extremity pain: a feasibility study.

    Science.gov (United States)

    Krampe, Jean; Wagner, Joanne M; Hawthorne, Kelly; Sanazaro, Deborah; Wong-Anuchit, Choochart; Budhathoki, Chakra; Lorenz, Rebecca A; Raaf, Soren

    2014-01-01

    A decreased gait speed in older adults can lead to dependency when the individuals are no longer able to participate in activities or do things for themselves. Thirty-seven senior apartment residents (31 females; Mean age=80.6 years; SD=8.9) with lower extremity pain/stiffness participated in a feasibility and preliminary efficacy study of 12 weeks (24 sessions). Healthy-Steps dance therapy compared to a wait-list control group. Small improvements in gait speed ([ES]=0.33) were noted for participants completing 19-24 dance sessions. Improvements in gait speed measured by a 10 Meter Walk Test (0.0517 m/s) exceeded 0.05 m/s, a value deemed to be meaningful in community dwelling older adults. These feasibility study findings support the need for additional research using dance-based therapy for older adults with lower extremity pain.

  6. Design and Analysis of a High Speed Carry Select Adder

    OpenAIRE

    Simarpreet Singh Chawla; Swapnil Aggarwal; Anshika; Nidhi Goel

    2015-01-01

    An optimal high-speed and low-power VLSI architecture requires an efficient arithmetic processing unit that is optimized for speed and power consumption. Adders are one of the widely used in digital integrated circuit and system design.High speed adder is the necessary component in a data path, e.g. Microprocessors and a Digital signal processor. The present paper proposes a novel high-speed adder by combining the advantages of Carry Look Ahead Adder (CLAA) and Carry Select Adder (CSA), devis...

  7. Design and Analysis of a High Speed Carry Select Adder

    OpenAIRE

    Simarpreet Singh Chawla; Swapnil Aggarwal; Anshika; Nidhi Goel

    2015-01-01

    An optimal high-speed and low-power VLSI architecture requires an efficient arithmetic processing unit that is optimized for speed and power consumption. Adders are one of the widely used in digital integrated circuit and system design. High speed adder is the necessary component in a data path, e.g. Microprocessors and a Digital signal processor. The present paper proposes a novel high-speed adder by combining the advantages of Carry Look Ahead Adder (CLAA) and Carry Select Adder (CSA), devi...

  8. High speed twin roll casting of 6061 alloy strips

    OpenAIRE

    T. Haga; Sakaguchi, H.; H. Watari; S. Kumai

    2008-01-01

    Purpose: of this paper is to clear the possibility of high speed roll casting of thin strips of two aluminum alloys:6061 and recycled 6061. Mechanical properties of the roll cast 6061 and recycled 6061 strips were investigated inthe frame of this purpose.Design/methodology/approach: Methods used in the present study were high speed twin roll caster and lowtemperature casting. These methods were used to realize rapid solidification and increase the casting speed.Findings: are that 6061 and rec...

  9. Structural vulnerability and intervention of high speed railway networks

    Science.gov (United States)

    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.

  10. High speed matrix processors using floating point representation

    Energy Technology Data Exchange (ETDEWEB)

    Birkner, D.A.

    1980-01-01

    The author describes the architecture of a high-speed matrix processor which uses a floating-point format for data representation. It is shown how multipliers and other LSI devices are used in the design to obtain the high speed of the processor.

  11. High-Speed Photo-Polarimetry of Magnetic Cataclysmic Variables

    Directory of Open Access Journals (Sweden)

    S. B. Potter

    2015-02-01

    Full Text Available I review recent highlights of the SAAO High-speed Photo-POlarimeter (HIPPO on the study of magnetic Cataclysmic Variables. Its high-speed capabilities are demonstrated with example observations made of the intermediate polar NY Lup and the polar IGRJ14536-5522.

  12. High Speed Turning of H-13 Tool Steel Using Ceramics and PCBN

    Science.gov (United States)

    Umer, Usama

    2012-09-01

    H-13 is the toughest tool steel used in machined die casting and forging dies. Due to its extreme hardness and poor thermal conductivity high speed cutting results in high temperature and stresses. This gives rise to surface damage of the workpiece and accelerated tool wear. This study evaluates the performance of different tools including ceramics and PCBN using practical finite element simulations and high speed orthogonal cutting tests. The machinability of H-13 was evaluated by tool wear, surface roughness, and cutting force measurements. From the 2D finite element model for orthogonal cutting, stresses and temperature distributions were predicted and compared for the different tool materials.

  13. High Speed Linear Induction Motor Efficiency Optimization

    Science.gov (United States)

    2005-06-01

    rotor d. 2 heightrotor ae + overhang length scon p-r length~~ 0 .5 7eto siemens .85 cru=5. 7-10 7 ___ se esc l:-z2.-17 siemens width: 100ikn 3.5 N:= 3...Vsnhs1482 Fp ot( slip1 ot) I K_______iplo)slppo speed ( slippiot) Vsych’ I~ nx sip (lipot 7t 2.106 1.5-.10 6 _ F~l0(s 5-100~ 5 50~ 0.9 0.8 0.7 0.6 0.5

  14. High Speed Laser 3D Measurement System

    Institute of Scientific and Technical Information of China (English)

    SONG Yuan-he; FAN Chang-zhou; GUO Ying; LI Hong-wei; ZHAO Hong

    2003-01-01

    Using the method of line structure light produced by a laser diode,three dimensional profile measurement is deeply researched.A hardware circuit developed is used to get the center position of light section for the improvement of the measurement speed.A double CCD compensation technology is used to improve the measurement precision. An easy and effective calibration method of the least squares to fit the parameter of system structure is used to get the relative coordinate relationship of objects and images of light section in the directions of height and axis. Sensor scanning segment by segment and layer by layer makes the measurement range expand greatly.

  15. Maneuverability Estimation of High-Speed Craft

    Science.gov (United States)

    2015-06-01

    different g-forces. The air-to-surface missile (Penguin anti-ship missile , AGM-114B/K/M Hellfire missile ) has a maximum speed around Mach 1.2. I assume...attacked by a missile . Three different attacking situations are analyzed in missile -vessel interactions for the safety of the vessel, and the optimum...distance has been found to start the escape maneuver. According to these escape situations, the missile should maintain a certain g-force to make an

  16. High Speed Sonar Array Depressor Program

    Science.gov (United States)

    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

  17. Spontaneous sidebanding in high speed rotordynamics

    Science.gov (United States)

    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.

  18. Intelligent high-speed cutting database system development

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the components of a high-speed cutting system are analyzed firstly.The component variables of the high-speed cutting system are classified into four types:uncontrolled variables,process variables,control variables,and output variables.The relationships and interactions of these variables are discussed.Then,by analyzing and comparing intelligent reasoning methods frequently used,the hybrid reasoning is employed to build the high-speed cutting database system.Then,the data structures of high-speed cutting case base and databases are determined.Finally,the component parts and working process of the high-speed cutting database system on the basis of hybrid reasoning are presented.

  19. Wake flow characteristics at high wind speed

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Larsen, Torben J.; Larsen, Gunner Chr.

    2016-01-01

    power. In the present study we simulate the wake flow for a row of turbines with the wind aligned with the row using a simplified approach. The velocity deficit, being a function of the thrust coefficient, is simulated based on the BEM solution for wake expansion. An axis-symmetric boundary layer...... equation model (the same as implemented in the DWM model) is subsequently used to develop the deficit down to the next turbine, and then the approach is successively repeated. Simulation results for four different spacing’s in a row with eight turbines show that there are two major flow regimes...... in the intersection region between the two flow regimes a strong variation in power and thrust occur, e.g. going from almost zero power to rated power for a wind speed change of 4m/s. Another result is that the inflow profile to the last turbine in the row at a wind speed of 16m/s for a spacing of 3D shows...

  20. Effect of welding current and speed on occurrence of humping bead in high-speed GMAW

    Institute of Scientific and Technical Information of China (English)

    Chen Ji; Wu Chuansong

    2009-01-01

    The developed mathematical model of humping formation mechanism in high-speed gas metal arc welding (GMAW) is used to analyze the effects of welding current and welding speed on the occurrence of humping bead. It considers both the momentum and heat content of backward flowing molten jet inside weld pool. Three-dimensional geometry of weld pool, the spacing between two adjacent humps and hump height along humping weld bead are calculated under different levels of welding current and welding speed. It shows that wire feeding rate, power intensity and the moment of backward flowing molten jet are the major factors on humping bead formation.

  1. Next Generation Modeling Technology for High Speed Rotorcraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a new generation of high speed rotorcraft has been hampered by both an absence of strong predictive methods for rotors operating at very high advance...

  2. High-speed camera characterization of voluntary eye blinking kinematics.

    Science.gov (United States)

    Kwon, Kyung-Ah; Shipley, Rebecca J; Edirisinghe, Mohan; Ezra, Daniel G; Rose, Geoff; Best, Serena M; Cameron, Ruth E

    2013-08-01

    Blinking is vital to maintain the integrity of the ocular surface and its characteristics such as blink duration and speed can vary significantly, depending on the health of the eyes. The blink is so rapid that special techniques are required to characterize it. In this study, a high-speed camera was used to record and characterize voluntary blinking. The blinking motion of 25 healthy volunteers was recorded at 600 frames per second. Master curves for the palpebral aperture and blinking speed were constructed using palpebral aperture versus time data taken from the high-speed camera recordings, which show that one blink can be divided into four phases; closing, closed, early opening and late opening. Analysis of data from the high-speed camera images was used to calculate the palpebral aperture, peak blinking speed, average blinking speed and duration of voluntary blinking and compare it with data generated by other methods previously used to evaluate voluntary blinking. The advantages of the high-speed camera method over the others are discussed, thereby supporting the high potential usefulness of the method in clinical research.

  3. High speed sampling circuit design for pulse laser ranging

    Science.gov (United States)

    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.

  4. Research on Aerodynamic Noise Reduction for High-Speed Trains

    OpenAIRE

    Yadong Zhang; Jiye Zhang; Tian Li; Liang Zhang; Weihua Zhang

    2016-01-01

    A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES) using the finite volume method with high-order difference schemes. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD)/Ffowcs Williams-Hawkings (FW-H)...

  5. Research on Aerodynamic Noise Reduction for High-Speed Trains

    OpenAIRE

    Yadong Zhang; Jiye Zhang; Tian Li; Liang Zhang; Weihua Zhang

    2016-01-01

    A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES) using the finite volume method with high-order difference schemes. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD)/Ffowcs Williams-Hawkings (FW-H)...

  6. Characterizing speed-independence of high-level designs

    DEFF Research Database (Denmark)

    Kishinevsky, Michael; Staunstrup, Jørgen

    1994-01-01

    types, and internal as well as external non-determinism. This makes it possible to verify the speed-independence of a design without providing an explicit realization of the environment. The verification can be done mechanically. A number of experimental designs have been verified including a speed......This paper characterizes the speed-independence of high-level designs. The characterization is a condition on the design description ensuring that the behavior of the design is independent of the speeds of its components. The behavior of a circuit is modeled as a transition system, that allows data...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. High-speed display system for animation using multimicrocomputer

    Energy Technology Data Exchange (ETDEWEB)

    Onda, K.; Oako, Y.

    1983-01-01

    A high-speed display system architecture for computer animation is proposed. Many picture memories, each of which is connected to a microcomputer, and display controller are used for producing and displaying pictures in parallel. This system can be realized with low-speed processors without specific hardwares to display natural movement. 1 ref.

  9. HULL GESTURE AND RESISTANCE PREDICTION OF HIGH-SPEED VESSELS*

    Institute of Scientific and Technical Information of China (English)

    NI Chong-ben; ZHU Ren-chuan; MIAO Guo-ping; FAN Ju

    2011-01-01

    Since trim and sinkage are significant while vessels are advancing forward with high speed, the predicted vessel resistance based on restrained model theory or experiment may not be real resistance of vessels during voyage. It is necessary to take the influence of hull gesture into account for oredicting the resistance of high-speed ship. In the present work the resistance problem of high speed ship is treated with the viscous flow theory, and the dynamic mesh technique is adopted to coincide with variation of hull gesture of high speed vessel on voyage. The simulation of the models of S60 ship and a trimaran moving in towing tank with high speed are conducted by using the above theory and technique. The corresponding numerical results are in good agreement with the experimental data. It indicates that the resistance prediction for high speed vessels should take hull gesture into consideration and the dynamic mesh method proposed here is effective in calculating the resistance of high speed vessels.

  10. Thermal Conductance Engineering for High-Speed TES Microcalorimeters

    Science.gov (United States)

    Hays-Wehle, J. P.; Schmidt, D. R.; Ullom, J. N.; Swetz, D. S.

    2016-07-01

    Many current and future applications for superconducting transition-edge sensor (TES) microcalorimeters require significantly faster pulse response than is currently available. X-ray spectroscopy experiments at next-generation synchrotron light sources need to successfully capture very large fluxes of photons, while detectors at free-electron laser facilities need pulse response fast enough to match repetition rates of the source. Additionally, neutrino endpoint experiments such as HOLMES need enormous statistics, yet are extremely sensitive to pile-up effects that can distort spectra. These issues can be mitigated only by fast rising and falling edges. To address these needs, we have designed high-speed TES detectors with novel geometric enhancements to increase the thermal conductance of pixels suspended on silicon nitride membranes. This paper shows that the thermal conductivity can be precisely engineered to values spanning over an order of magnitude to achieve fast thermal relaxation times tailored to the relevant applications. Using these pixel prototypes, we demonstrate decay time constants faster than 100 μ s, while still maintaining spectral resolution of 3 eV FWHM at 1.5 keV. This paper also discusses the trade-offs inherent in reducing the pixel time constant, such as increased bias current leading to degradation in energy resolution, and potential modifications to improve performance.

  11. A high-speed linear algebra library with automatic parallelism

    Science.gov (United States)

    Boucher, Michael L.

    1994-01-01

    Parallel or distributed processing is key to getting highest performance workstations. However, designing and implementing efficient parallel algorithms is difficult and error-prone. It is even more difficult to write code that is both portable to and efficient on many different computers. Finally, it is harder still to satisfy the above requirements and include the reliability and ease of use required of commercial software intended for use in a production environment. As a result, the application of parallel processing technology to commercial software has been extremely small even though there are numerous computationally demanding programs that would significantly benefit from application of parallel processing. This paper describes DSSLIB, which is a library of subroutines that perform many of the time-consuming computations in engineering and scientific software. DSSLIB combines the high efficiency and speed of parallel computation with a serial programming model that eliminates many undesirable side-effects of typical parallel code. The result is a simple way to incorporate the power of parallel processing into commercial software without compromising maintainability, reliability, or ease of use. This gives significant advantages over less powerful non-parallel entries in the market.

  12. Improving the critical speeds of high-speed trains using magnetorheological technology

    Science.gov (United States)

    Sun, Shuaishuai; Deng, Huaxia; Li, Weihua; Du, Haiping; Qing Ni, Yi; Zhang, Jin; Yang, Jian

    2013-11-01

    With the rapid development of high-speed railways, vibration control for maintaining stability, passenger comfort, and safety has become an important area of research. In order to investigate the mechanism of train vibration, the critical speeds of various DOFs with respect to suspension stiffness and damping are first calculated and analyzed based on its dynamic equations. Then, the sensitivity of the critical speed is studied by analyzing the influence of different suspension parameters. On the basis of these analyses, a conclusion is drawn that secondary lateral damping is the most sensitive suspension damper. Subsequently, the secondary lateral dampers are replaced with magnetorheological fluid (MRF) dampers. Finally, a high-speed train model with MRF dampers is simulated by a combined ADAMS and MATLAB simulation and tested in a roller rig test platform to investigate the mechanism of how the MRF damper affects the train’s stability and critical speed. The results show that the semi-active suspension installed with MRF dampers substantially improves the stability and critical speed of the train.

  13. High speed twin roll casting of 6016 strip

    OpenAIRE

    Haga, T.; Ikawa, M; H.Watari; S. Kumai

    2006-01-01

    Purpose: of this paper is to clear the possibility of high speed roll casting of thin aluminum alloy strip. 6016aluminum alloy is used for sheet metal of the automobile. Therefore, casting of 6016 was tried in this study.Castability and characteristics of roll cast 6016 strip were investigated.Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designedto overcome the low castability of the twin roll caster.Findings: are as below. The 6016 could...

  14. High-speed AFM of human chromosomes in liquid

    Science.gov (United States)

    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.

  15. Trend on High-speed Power Line Communication Technology

    Science.gov (United States)

    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.

  16. AN ANALYSIS METHOD FOR HIGH-SPEED CIRCUIT SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new method for analyzing high-speed circuit systems is presented. The method adds transmission line end currents to the circuit variables of the classical modified nodal approach. Then the matrix equation describing high-speed circuit system can be formulated directly and analyzed conveniently for its normative form. A time-domain analysis method for transmission lines is also introduced. The two methods are combined together to efficiently analyze high-speed circuit systems having general transmission lines. Numerical experiment is presented and the results are compared with that calculated by Hspice.

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

    Science.gov (United States)

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

    2017-06-01

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

  18. High speed high dynamic range high accuracy measurement system

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-29

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

  19. FPGA Flash Memory High Speed Data Acquisition

    Science.gov (United States)

    Gonzalez, April

    2013-01-01

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

  20. EXPERIMENTAL INVESTIGATION ON SOUND SPEED PROPAGATING THROUGH HIGH SPEED AERATED FLOW IN OPEN CHANNEL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experiment concerning the sound propaga-tion in aerated open channel flow was designed and conductedin a variable slope chute. The acquisition of sound data wasdone by the hydro-phones installed into the bottom wall of thechute. The data were analyzed and processed by the tape re-corder and a 3562A analyzer. The primary experimetal resultsindicated that the sound speed in aerated flow is varied with the air concentration and highly lower than each of the soundspeed in pure water or air. As released by the derived theoryformula, the minimum sound of 24m/s in aerated flow hap-pened when the air concentration achieved to 50%. This resultshows that the compressibility of high speed aerated flowshould be considered when the air concentration is near to50%. A criterion of compressibility of high speed aerated flowwas also giv. En in this paper.

  1. Extreme-value time-series analysis of Australian Region A gust wind speeds to examine instrument bias

    Science.gov (United States)

    Cechet, R. P.; Sanabria, L. A.

    2010-08-01

    Australian building codes through the Australia/New Zealand Wind Actions Standard as well as the wind engineering community in general rely to a significant extent on the peak gust wind speed observations collected over more than 70 years by the Australian Bureau of Meteorology (BoM). In the mid-1980's BoM commenced a program to replace the aging pressure tube Dines anemometers with cup anemometers. During the replacement procedure, many localities had more than one type of anemometer operating, recording extreme events. Systematic differences between instrument measurements during this overlap period raised serious concerns about the utility of the peak gust wind speed database. This paper presents the results of a reanalysis of the current BoM peak wind gust database for the non-cyclonic region (Region A) of the Australia/New Zealand Wind Actions Standard. The study utilises extreme value distribution analysis and compares estimates of the 500-year return-period (RP) peak gust wind exceedance level derived from segments of the record measured with the Dines and replacement anemometers. Results indicate that the later period appears to have a significant reduction in extreme events; 17 of 31 sites have a mean 500 year RP exceedance level for the replacement anemometer section of the record below the lower 95% confidence limit for the Dines anemometer part of the record. The 3PM mean wind speed time-series observations have also been examined, and they exhibit a similar trend.

  2. Effects of High-Speed Power Training on Muscle Performance and Braking Speed in Older Adults

    Directory of Open Access Journals (Sweden)

    Stephen P. Sayers

    2012-01-01

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

  3. INTELLIGENT TOOL CONDITION MONITORING IN HIGH-SPEED ...

    African Journals Online (AJOL)

    MR PRINCE

    work model has been developed for on-line condition monitoring of tool wear in high-speed ... degraded behaviours in wire electrical dis- ... mathematical models such as regression (Lin et ... an 11 kW Computer Numerical Controlled.

  4. High-Speed Thermal Characterization of Cryogenic Flows Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna proposes to continue development on a high-speed fiber optic sensor and readout system for cryogenic temperature measurements in liquid oxygen (LOX) and liquid...

  5. High speed railway track dynamics models, algorithms and applications

    CERN Document Server

    Lei, Xiaoyan

    2017-01-01

    This book systematically summarizes the latest research findings on high-speed railway track dynamics, made by the author and his research team over the past decade. It explores cutting-edge issues concerning the basic theory of high-speed railways, covering the dynamic theories, models, algorithms and engineering applications of the high-speed train and track coupling system. Presenting original concepts, systematic theories and advanced algorithms, the book places great emphasis on the precision and completeness of its content. The chapters are interrelated yet largely self-contained, allowing readers to either read through the book as a whole or focus on specific topics. It also combines theories with practice to effectively introduce readers to the latest research findings and developments in high-speed railway track dynamics. It offers a valuable resource for researchers, postgraduates and engineers in the fields of civil engineering, transportation, highway & railway engineering.

  6. implementation and comparative study of a high speed multimode ...

    African Journals Online (AJOL)

    SUMAN HALDAR, SOUMITA HALDAR CHAKRABORTY, PRADIPTAMAITI, PRATIK KUMAR SINHA, PIJUSH BISWAS, Dr. AMITAVA SINHA

    2016-07-07

    Jul 7, 2016 ... The key feature of the work is reduced power and simple circuitry, without ... Keywords: Digital Communication, Multimode Modulator, High Speed ..... Implementation of Universal Modulator using Co-ordinate Rotation Digital ...

  7. Next Generation Modeling Technology for High Speed Rotorcraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent R&D associated with designing high speed rotorcraft has been greatly hampered by a lack of test data and confidence in predictions for rotors operating...

  8. CSIR National Laser Centre develops a high speed OCT system

    CSIR Research Space (South Africa)

    Sharma, Ameeth

    2016-11-01

    Full Text Available impact areas and applications include polymer characterisation, surface and thin-film characterisation and biometrics. The National laser Centre has developed a high speed, large area optical coherence tomography (OCT) prototype for fingerprint scanning...

  9. Parallelism and pipelining in high-speed digital simulators

    Science.gov (United States)

    Karplus, W. J.

    1983-01-01

    The attainment of high computing speed as measured by the computational throughput is seen as one of the most challenging requirements. It is noted that high speed is cardinal in several distinct classes of applications. These classes are then discussed; they comprise (1) the real-time simulation of dynamic systems , (2) distributed parameter systems, and (3) mixed lumped and distributed systems. From the 1950s on, the quest for high speed in digital simulators concentrated on overcoming the limitations imposed by the so-called von Neumann bottleneck. Two major architectural approaches have made ig possible to circumvent this bottleneck and attain high speeds. These are pipelining and parallelism. Supercomputers, peripheral array processors, and microcomputer networks are then discussed.

  10. Design of high speed camera based on CMOS technology

    Science.gov (United States)

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

    2007-12-01

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

  11. Supersonic stall flutter of high-speed fans

    Science.gov (United States)

    Adamczyk, J. J.; Stevans, W.; Jutras, R.

    1981-01-01

    An analytical model is proposed for predicting the onset of supersonic stall bending flutter in high-speed rotors. The analysis is based on a modified two-dimensional, compressible, unsteady actuator disk theory. The stability boundary predicted by the analysis is shown to be in good agreement with the measured boundary of a high speed fan. The prediction that the flutter mode would be a forward traveling wave sensitive to wheel speed and aerodynamic loading is confirmed by experimental measurements. In addition, the analysis shows that reduced frequency and dynamic head also play a significant role in establishing the supersonic stall bending flutter boundary of an unshrouded fan.

  12. Application of Beyond Bound Decoding for High Speed Optical Communications

    DEFF Research Database (Denmark)

    Li, Bomin; Larsen, Knud J.; Vegas Olmos, Juan José;

    2013-01-01

    This paper studies the application of beyond bound decoding method for high speed optical communications. This hard-decision decoding method outperforms traditional minimum distance decoding method, with a total net coding gain of 10.36 dB.......This paper studies the application of beyond bound decoding method for high speed optical communications. This hard-decision decoding method outperforms traditional minimum distance decoding method, with a total net coding gain of 10.36 dB....

  13. A Multiprocessor Communication Architecture For High Speed Networks

    CERN Document Server

    S, Iyengar; Roy, A A; Sanyal, S; Singhi, N M; Feng, Wu Geng

    2010-01-01

    Over the years, communication speed of networks has increased from a few Kbps to several Mbps, as also the bandwidth demand, Communication Protocols, however have not improved to that extent. With the advent of Wavelength Division Multiplexing (WDM), it is now possible to "tune" protocols to current and future demands. The purpose of this paper is to evolve a High Speed Network architecture, which will cater to the needs of bandwidth-consuming applications, such as voice, video and high definition image transmission.

  14. High-speed optical signal processing using time lenses

    DEFF Research Database (Denmark)

    Galili, Michael; Hu, Hao; Guan, Pengyu;

    2015-01-01

    This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

  15. High Speed Frame Synchronization and Viterbi Decoding

    DEFF Research Database (Denmark)

    Paaske, Erik; Justesen, Jørn; Larsen, Knud J.

    1996-01-01

    The purpose of Phase 1 of the study is to describe the system structure and algorithms in sufficient detail to allow drawing the high level architecture of units containing frame synchronization and Viterbi decoding. The systems we consider are high data rate space communication systems. Also......, the systems use some form of QPSK modulation and transmit data in frames separated by a sync marker and protected by error-correcting codes. We first give a survey of trends within the area of space modulation systems. We then discuss and define the interfaces and operating modes of the relevant system...... components. Node synchronization performed within a Viterbi decoder is discussed, and algorithms for frame synchronization are described and analyzed. We present a list of system configurations that we find potentially useful. Further, the high level architecture of units that contain frame synchronization...

  16. Flat belt continuously variable high speed drive. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kumm, E.L.

    1992-02-01

    A study was undertaken at Kumm Industries funded by DOE in the NBS/DOE Energy-Related Inventions Program starting in August 1990 to design, construct and test a novel very high speed flat belt drive. The test arrangement as shown in Figure 1 consists of a multiple belt-pulley configuration that transmits power from a low speed (2000--4000 RPM) input to a small pulley ``turbine`` (27,000 to 55,000 RPM) and then to the low speed output variable radius pulley (2000--5000 RPM) via a special self-active tensioner. Transmitting 25 HP to and from the ``turbine`` corresponds to obtaining 50 HP in one direction only in a possible turbo compounded engine application. The high speed of the ``turbine`` belts, i.e. 100 meters/sec. at 55,000 RPM, while transferring substantial power is a new much higher operating regime for belts. The study showed that the available belts gave overall test rig efficiencies somewhat above 80% for the higher speeds (50,000 RPM) and higher powers (corresponding to above 90% in the turbocompound application) and a significantly better efficiencies at slightly lower speeds. The tests revealed a number of improved approaches in the design of such high speed drives. It appears that there is considerable possibility for further improvement and application of such equipment.

  17. Analysis of external noise spectrum of high-speed railway

    Institute of Scientific and Technical Information of China (English)

    邓永权; 肖新标; 何宾; 金学松

    2014-01-01

    A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteristics considered here include identifying the exterior main sources and their locations, their frequency components including the Doppler effect due to the noise sources moving at high speed, the sound field intensity around the train in high-speed operation, the sound radiation path out of the train, and the pressure level and frequency components of the noise at the measuring points specified by the International Organization for Standardization(ISO). The characteristics of the high-speed train exterior noise of the high speed railways in operation were introduced. The advanced measuring systems and their principles for clearly indentifying the exterior noise sources were discussed in detail. Based on the concerned noise results measured at sites, a prediction model was developed to calculate the sound level and the characteristics of the exterior noise at any point where it is difficult to measure and to help to make the exterior noise spectrums. This model was also verified with the test results. The verification shows that there is a good agreement between the theoretical and experimental results.

  18. High-speed precision motion control

    CERN Document Server

    Yamaguchi, Takashi; Pang, Chee Khiang

    2011-01-01

    Written for researchers and postgraduate students in Control Engineering, as well as professionals in the Hard Disk Drive industry, this book discusses high-precision and fast servo controls in Hard Disk Drives (HDDs). The editors present a number of control algorithms that enable fast seeking and high precision positioning, and propose problems from commercial products, making the book valuable to researchers in HDDs. Each chapter is self contained, and progresses from concept to technique, present application examples that can be used within automotive, aerospace, aeronautical, and manufactu

  19. High speed multispectral fluorescence lifetime imaging

    NARCIS (Netherlands)

    Fereidouni, F.; Reitsma, K.; Gerritsen, H.C.

    2013-01-01

    We report a spectrally resolved fluorescence lifetime imaging system based on time gated single photon detection with a fixed gate width of 200 ps and 7 spectral channels. Time gated systems can operate at high count rates but usually have large gate widths and sample only part of the fluorescence d

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

    Science.gov (United States)

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

    1991-04-01

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

  1. High Speed Frame Synchronization and Viterbi Decoding

    DEFF Research Database (Denmark)

    Paaske, Erik; Justesen, Jørn; Larsen, Knud J.

    1998-01-01

    The study has been divided into two phases. The purpose of Phase 1 of the study was to describe the system structure and algorithms in sufficient detail to allow drawing the high level architecture of units containing frame synchronization and Viterbi decoding. After selection of which specific...... separated by a sync marker and protected by error-correcting codes. We first give a survey of trends within the area of space modulation systems. We then discuss and define the interfaces and operating modes of the relevant system components. We present a list of system configurations that we find...... potentially useful.Algorithms for frame synchronization are described and analyzed. Further, the high level architecture of units that contain frame synchronization and various other functions needed in a complete system is presented. Two such units are described, one for placement before the Viterbi decoder...

  2. High-speed quantum networking by ship

    Science.gov (United States)

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

    2016-11-01

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

  3. High-speed quantum networking by ship.

    Science.gov (United States)

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

    2016-11-02

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

  4. High-speed cineradiography using electronic imaging

    Science.gov (United States)

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

    1993-01-01

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

  5. High speed cineradiography using electronic imaging

    Science.gov (United States)

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

    1992-12-01

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

  6. High Speed Blood and Transfusion Equipment

    Science.gov (United States)

    2013-10-14

    used to calculate percent hemolysis of red blood cells. Plasma Free Hemoglobin Assay - pRBCs samples were assayed for plasma free hemoglobin (PFH...resulting in high temperatures gradients that preludes blood hemolysis if fluid flow stops. • The solenoid valve has been replaced with a valve of a more...pRBCs to test efficacy. Both pre and post cartridge blood samples were evaluated to determine if any damage may have occurred to blood cells. The

  7. Rad-Tolerant, Thermally Stable, High-Speed Fiber-Optic Network for Harsh Environments

    Science.gov (United States)

    Leftwich, Matt; Hull, Tony; Leary, Michael; Leftwich, Marcus

    2013-01-01

    Future NASA destinations will be challenging to get to, have extreme environmental conditions, and may present difficulty in retrieving a spacecraft or its data. Space Photonics is developing a radiation-tolerant (rad-tolerant), high-speed, multi-channel fiber-optic transceiver, associated reconfigurable intelligent node communications architecture, and supporting hardware for intravehicular and ground-based optical networking applications. Data rates approaching 3.2 Gbps per channel will be achieved.

  8. Common lower extremity injuries in female high school soccer ...

    African Journals Online (AJOL)

    Common lower extremity injuries in female high school soccer players in ... and fitness and not wearing shin guards are risk factors for injury in female soccer ... do not differ from the studies done in male adolescent and adult soccer players.

  9. Advanced Extremely High Frequency Satellite (AEHF)

    Science.gov (United States)

    2015-12-01

    High Frequency Satellite (AEHF) is a joint service satellite communications system that provides global , survivable, secure, protected, and jam...three satellites fully integrated into the Milstar constellation. October 2014: On October 16, 2014, the program received PEO certification for the...Combined Orbital Operation, Logistics Sustainment ( COOLS ) contract, it will be completed and coordinated in CY 2016. The AEHF system being sustained

  10. Extremely high Q-factor toroidal metamaterials

    CERN Document Server

    Basharin, Alexey A; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N; Ustinov, Alexey V

    2016-01-01

    We demonstrate that, owing to the unique topology of the toroidal dipolar mode, its electric/magnetic field can be spatially confined within subwavelength, externally accessible regions of the metamolecules, which makes the toroidal planar metamaterials a viable platform for high Q-factor resonators due to interfering toroidal and other dipolar modes in metamolecules.

  11. High-speed integrated electroabsorption modulators

    Science.gov (United States)

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

    1997-04-01

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

  12. Workshop on extremely high energy density plasmas and their diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Shozo (ed.)

    2001-09-01

    Compiled are the papers presented at the workshop on 'Extremely High Energy Density Plasmas and Their Diagnostics' held at National Institute for Fusion Science. The papers cover physics and applications of extremely high-energy density plasmas such as dense z-pinch, plasma focus, and intense pulsed charged beams. Separate abstracts were presented for 7 of the papers in this report. The remaining 25 were considered outside the subject scope of INIS. (author)

  13. Giga bit per second Differential Scheme for High Speed Interconnect

    Directory of Open Access Journals (Sweden)

    Mandeep Singh Narula

    2012-02-01

    Full Text Available The performance of many digital systems today is limited by the interconnection bandwidth between chips. Although the processing performance of a single chip has increased dramatically since the inception of the integrated circuit technology, the communication bandwidth between chips has not enjoyed as much benefit. Most CMOS chips, when communicating off-chip, drive un terminated lines with full-swing CMOS drivers. Such full-swing CMOS interconnect ring-up the line, and hence has a bandwidth that is limited by the length of the line rather than the performance of the semiconductor technology. Thus, as VLSI technology scales, the pin bandwidth does not improve with the technology, but rather remains limited by board and cable geometry, making off-chip bandwidth an even more critical bottleneck. In order to increase the I/O Bandwidth, some efficient high speed signaling standard must be used which considers the line termination, signal integrity, power dissipation, noise immunity etc In this work, a transmitter has been developed for high speed off chip communication. It consists of low speed input buffer, serializer which converts parallel input data into serial data and a current mode driver which converts the voltage mode input signals into current over the transmission line. Output of 32 low speed input buffers is fed to two serializer, each serializer converting 16 bit parallel data into serial data stream. Output of two serializers is fed to LVDS current mode driver. The serial link technique used in this work is the time division multiplex (TDM and point-to-point technique. It means that the low-speed parallel signals are transferred to the high-speed serial signal at the transmitter end and the high-speed serial signal is transferred to the low-speed parallel signals at the receiver end. Serial link is the design of choice in any application where the cost of the communication channel is high and duplicating the links in large numbers is

  14. Giga bit per second Differential Scheme for High Speed Interconnect

    Directory of Open Access Journals (Sweden)

    Mandeep Singh Narula

    2012-03-01

    Full Text Available The performance of many digital systems today is limited by the interconnection bandwidth between chips. Although the processing performance of a single chip has increased dramatically since the inception of the integrated circuit technology, the communication bandwidth between chips has not enjoyed as much benefit. Most CMOS chips, when communicating off-chip, drive unterminated lines with full-swing CMOS drivers. Such full-swing CMOS interconnect ring-up the line, and hence has a bandwidth that is limited by the length of the line rather than the performance of the semiconductor technology. Thus, as VLSI technology scales, the pin bandwidth does not improve with the technology, but rather remains limited by board and cable geometry, making off-chip bandwidth an even more critical bottleneck. In order to increase the I/O Bandwidth, some efficient high speed signaling standard must be used which considers the line termination, signal integrity, power dissipation, noise immunity etc In this work, a transmitter has been developed for high speed offchip communication. It consists of low speed input buffer, serializer which converts parallel input data into serial data and a current mode driver which converts the voltage mode input signals into current over the transmission line. Output of 32 low speed input buffers is fed to two serializer, each serializer converting 16 bit parallel data into serial data stream. Output of two serializers is fed to LVDS current mode driver. The serial link technique used in this work is the time division multiplex (TDM and point-to-point technique. It means that the low-speed parallel signals are transferred to the high-speed serial signal at the transmitter end and the high-speed serial signal is transferred to the low-speed parallel signals at the receiver end. Serial link is the design of choice in any application where the cost of the communication channel is high and duplicating the links in large numbers is

  15. High-speed analog-to-digital conversion

    CERN Document Server

    Demler, Michael J

    1991-01-01

    This book covers the theory and applications of high-speed analog-to-digital conversion. An analog-to-digital converter takes real-world inputs (such as visual images, temperature readings, and rates of speed) and transforms them into digital form for processing by computer. This book discusses the design and uses of such circuits, with particular emphasis on improving the speed of the conversion process and the accuracy of its output--how well the output is a corresponding digital representation of the output*b1input signal. As computers become increasingly interfaced to the outside world, ""

  16. High speed inspection of ceramic fuels

    Energy Technology Data Exchange (ETDEWEB)

    McLemore, D. R.

    1979-03-01

    A fuel pellet inspection system is under development and evaluation for use in the High Performance Fuel Laboratory (HPFL) at Richland, Washington. A major operation in this process is the gaging of fuel pellets for dimensions (length and diameter), surface flaws and weight. The system is modularly designed to simplify maintenance operations thereby reducing personnel exposure. The inspection system is divided into two parts: mechanical and electronic. The mechanical portion consists of a pellet handling system; inspection stations for measuring length, diameter, weight and surface flaws; and a glovebox-like containment which isolates Special Nuclear Material (SNM) from the surrounding environment. The electronic portion is a dedicated minicomputer for process control and a supervisory computer system which will be located in a centralized control center and be shared with other development activities in the HPFL.

  17. The association between social participation and lower extremity muscle strength, balance, and gait speed in US adults.

    Science.gov (United States)

    Warren, Meghan; Ganley, Kathleen J; Pohl, Patricia S

    2016-12-01

    Social participation is associated with healthy aging, and although associations have been reported between social participation and demographics, no published studies have examined a relationship between social participation and measures amenable to intervention. The purpose was to explore the association between self-reported social participation and lower extremity strength, balance, and gait speed. A cross-sectional analysis of US adults (n = 2291; n = 1,031 males; mean ± standard deviation age 63.5 ± 0.3 years) from the 2001-2 National Health and Nutrition Examination Survey was conducted. Two questions about self-reported difficulty with social participation were categorized into limited (yes/no). The independent variables included knee extension strength (n = 1537; classified as tertiles of weak, normal, and strong), balance (n = 1813; 3 tests scored as pass/fail), and gait speed (n = 2025; dichotomized as slow [less than 1.0 m/s] and fast [greater than or equal to 1.0 m/s]). Logistic regression, accounting for the complex survey design and adjusting for age, sex, physical activity, and medical conditions, was used to estimate the odds of limitation in social participation with each independent variable. Alpha was decreased to 0.01 due to multiple tests. Slower gait speed was significantly associated with social participation limitation (odds ratio = 3.1; 99% confidence interval: 1.5-6.2). No significant association was found with social participation and lower extremity strength or balance. The odds of having limitation in social participation were 3 times greater in those with slow gait speed. Prospective studies should examine the effect of improved gait speed on levels of social participation.

  18. The association between social participation and lower extremity muscle strength, balance, and gait speed in US adults

    Directory of Open Access Journals (Sweden)

    Meghan Warren

    2016-12-01

    Full Text Available Social participation is associated with healthy aging, and although associations have been reported between social participation and demographics, no published studies have examined a relationship between social participation and measures amenable to intervention. The purpose was to explore the association between self-reported social participation and lower extremity strength, balance, and gait speed. A cross-sectional analysis of US adults (n = 2291; n = 1,031 males; mean ± standard deviation age 63.5 ± 0.3 years from the 2001–2 National Health and Nutrition Examination Survey was conducted. Two questions about self-reported difficulty with social participation were categorized into limited (yes/no. The independent variables included knee extension strength (n = 1537; classified as tertiles of weak, normal, and strong, balance (n = 1813; 3 tests scored as pass/fail, and gait speed (n = 2025; dichotomized as slow [less than 1.0 m/s] and fast [greater than or equal to 1.0 m/s]. Logistic regression, accounting for the complex survey design and adjusting for age, sex, physical activity, and medical conditions, was used to estimate the odds of limitation in social participation with each independent variable. Alpha was decreased to 0.01 due to multiple tests. Slower gait speed was significantly associated with social participation limitation (odds ratio = 3.1; 99% confidence interval: 1.5–6.2. No significant association was found with social participation and lower extremity strength or balance. The odds of having limitation in social participation were 3 times greater in those with slow gait speed. Prospective studies should examine the effect of improved gait speed on levels of social participation.

  19. High Speed Imaging of Diesel Fuel Sprays

    Science.gov (United States)

    Jackson, Ja'kira; Bittle, Joshua

    2016-11-01

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

  20. SPH simulations of high-speed collisions

    Science.gov (United States)

    Rozehnal, Jakub; Broz, Miroslav

    2016-10-01

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

  1. ALICE HLT high speed tracking on GPU

    CERN Document Server

    Gorbunov, Sergey; Aamodt, Kenneth; Alt, Torsten; Appelshauser, Harald; Arend, Andreas; Bach, Matthias; Becker, Bruce; Bottger, Stefan; Breitner, Timo; Busching, Henner; Chattopadhyay, Sukalyan; Cleymans, Jean; Cicalo, Corrado; Das, Indranil; Djuvsland, Oystein; Engel, Heiko; Erdal, Hege Austrheim; Fearick, Roger; Haaland, Oystein Senneset; Hille, Per Thomas; Kalcher, Sebastian; Kanaki, Kalliopi; Kebschull, Udo Wolfgang; Kisel, Ivan; Kretz, Matthias; Lara, Camillo; Lindal, Sven; Lindenstruth, Volker; Masoodi, Arshad Ahmad; Ovrebekk, Gaute; Panse, Ralf; Peschek, Jorg; Ploskon, Mateusz; Pocheptsov, Timur; Ram, Dinesh; Rascanu, Theodor; Richter, Matthias; Rohrich, Dieter; Ronchetti, Federico; Skaali, Bernhard; Smorholm, Olav; Stokkevag, Camilla; Steinbeck, Timm Morten; Szostak, Artur; Thader, Jochen; Tveter, Trine; Ullaland, Kjetil; Vilakazi, Zeblon; Weis, Robert; Yin, Zhong-Bao; Zelnicek, Pierre

    2011-01-01

    The on-line event reconstruction in ALICE is performed by the High Level Trigger, which should process up to 2000 events per second in proton-proton collisions and up to 300 central events per second in heavy-ion collisions, corresponding to an inp ut data stream of 30 GB/s. In order to fulfill the time requirements, a fast on-line tracker has been developed. The algorithm combines a Cellular Automaton method being used for a fast pattern recognition and the Kalman Filter method for fitting of found trajectories and for the final track selection. The tracker was adapted to run on Graphics Processing Units (GPU) using the NVIDIA Compute Unified Device Architecture (CUDA) framework. The implementation of the algorithm had to be adjusted at many points to allow for an efficient usage of the graphics cards. In particular, achieving a good overall workload for many processor cores, efficient transfer to and from the GPU, as well as optimized utilization of the different memories the GPU offers turned out to be cri...

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

    Science.gov (United States)

    Kottapalli, Sesi B. R.

    2010-01-01

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

  3. Quality of service on high-speed data networks

    Science.gov (United States)

    Barbero, Ezio; Antonelli, Ferruccio

    1995-02-01

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

  4. Recent progress on high-speed optical transmission

    Directory of Open Access Journals (Sweden)

    Jianjun Yu

    2016-05-01

    Full Text Available The recently reported high spectral efficiency (SE and high-baud-rate signal transmission are all based on digital coherent optical communications and digital signal processing (DSP. DSP simplifies the reception of advanced modulation formats and also enables the major electrical and optical impairments to be processed and compensated in the digital domain, at the transmitter or receiver side. In this paper, we summarize the research progress on high-speed signal generation and detection and also show the progress on DSP for high-speed signal detection. We also report the latest progress on multi-core and multi-mode multiplexing.

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

    Science.gov (United States)

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

    2016-10-20

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

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

    Science.gov (United States)

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

    2014-06-01

    In the present study, rural soundscapes with high-speed train noise were assessed through laboratory experiments. A total of ten sites with varying landscape metrics were chosen for audio-visual recording. The acoustical characteristics of the high-speed train noise were analyzed using various noise level indices. Landscape metrics such as the percentage of natural features (NF) and Shannon's diversity index (SHDI) were adopted to evaluate the landscape features of the ten sites. Laboratory experiments were then performed with 20 well-trained listeners to investigate the perception of high-speed train noise in rural areas. The experiments consisted of three parts: 1) visual-only condition, 2) audio-only condition, and 3) combined audio-visual condition. The results showed that subjects' preference for visual images was significantly related to NF, the number of land types, and the A-weighted equivalent sound pressure level (LAeq). In addition, the visual images significantly influenced the noise annoyance, and LAeq and NF were the dominant factors affecting the annoyance from high-speed train noise in the combined audio-visual condition. In addition, Zwicker's loudness (N) was highly correlated with the annoyance from high-speed train noise in both the audio-only and audio-visual conditions. © 2013.

  7. High speed twin roll caste for aluminum alloy thin strip

    Directory of Open Access Journals (Sweden)

    T. Haga

    2007-09-01

    Full Text Available Purpose: In the present study, effectiveness of a high-speed twin roll caster for recycling aluminum alloy was investigated.Design/methodology/approach: The effects of the high-speed twin roll caster on alleviating the deterioration of mechanical properties by impurities were investigated. Properties of the cast strip were investigated by metalography, a tension test, and a bending test.Findings: A vertical type twin roll caster for strip casting of aluminum alloys was devised. The strip, which was thinner than 3 mm, could be cast at speeds higher than 60 m/min. Features of the twin roll casters are as below. Copper rolls were used and lubricant was not used in order to increase the casting speed. A casting nozzle was used to set the solidification length precisely. Heat transfer between melt and the roll was improved by hydrostatic pressure of the melt. Separating force was very small in order to prevent sticking of the strip to the roll. Low superheat casting was carried out in order to improve microstructure of the strip. In the present study, effectiveness of a high-speed and high-cooling rate twin roll caster of the present study for recycling aluminum alloy was investigated. Fe was added as impurity to 6063 and A356. The roll caster of the present study was useful to decrease the influence of impurity of Fe.Research limitations/implications: A high-speed twin roll caster of vertical type was designed and assembled to cast aluminum alloy thin strip.Originality/value: The results demonstrate that the high-speed twin roll caster can improve the deterioration by impurities.

  8. Effects of obesity on lower extremity muscle function during walking at two speeds.

    Science.gov (United States)

    Lerner, Zachary F; Board, Wayne J; Browning, Raymond C

    2014-03-01

    Walking is a recommended form of physical activity for obese adults, yet the effects of obesity and walking speed on the biomechanics of walking are not well understood. The purpose of this study was to examine joint kinematics, muscle force requirements and individual muscle contributions to the walking ground reaction forces (GRFs) at two speeds (1.25 ms(-1) and 1.50 ms(-1)) in obese and nonobese adults. Vasti (VAS), gluteus medius (GMED), gastrocnemius (GAST), and soleus (SOL) forces and their contributions to the GRFs were estimated using three-dimensional musculoskeletal models scaled to the anthropometrics of nine obese (35.0 (3.78 kg m(-2))); body mass index mean (SD)) and 10 nonobese (22.1 (1.02 kg m(-2))) subjects. The obese individuals walked with a straighter knee in early stance at the faster speed and greater pelvic obliquity during single limb support at both speeds. Absolute force requirements were generally greater in obese vs. nonobese adults, the main exception being VAS, which was similar between groups. At both speeds, lean mass (LM) normalized force output for GMED was greater in the obese group. Obese individuals appear to adopt a gait pattern that reduces VAS force output, especially at speeds greater than their preferred walking velocity. Greater relative GMED force requirements in obese individuals may contribute to altered kinematics and increased risk of musculoskeletal injury/pathology. Our results suggest that obese individuals may have relative weakness of the VAS and hip abductor muscles, specifically GMED, which may act to increase their risk of musculoskeletal injury/pathology during walking, and therefore may benefit from targeted muscle strengthening. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Gabriel P. [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000, Brazil and Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Viana, Rodrigo S. S.; Yoriyaz, Hélio [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000 (Brazil); Podesta, Mark [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Rubo, Rodrigo A.; Sales, Camila P. de [Hospital das Clínicas da Universidade de São Paulo—HC/FMUSP, São Paulo 05508-000 (Brazil); Reniers, Brigitte [Department of Radiation Oncology - MAASTRO, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Research Group NuTeC, CMK, Hasselt University, Agoralaan Gebouw H, Diepenbeek B-3590 (Belgium); Verhaegen, Frank, E-mail: frank.verhaegen@maastro.nl [Department of Radiation Oncology - MAASTRO, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec H3G 1A4 (Canada)

    2015-01-15

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

  10. High resolution spectroscopy of six new extreme helium stars

    Science.gov (United States)

    Heber, U.; Jones, G.; Drilling, J. S.

    1986-01-01

    High resolution spectra of six newly discovered extreme helium stars are presented. LSS 5121 is shown to be a spectroscopical twin of the hot extreme helium star HD 160641. A preliminary LTE analysis of LSS 3184 yielded an effective temperature of 22,000 K and a surface gravity of log g = 3.2. Four stars form a new subgroup, classified by sharp-lined He I spectra and pronounced O II spectra, and it is conjectured that these lie close to the Eddington limit. The whole group of extreme helium stars apparently is inhomogeneous with respect to luminosity to mass ratio and chemical composition.

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

    Science.gov (United States)

    Handschuh, Robert F.

    2003-01-01

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

  12. Review of actuators for high speed active flow control

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; LUO ZhenBing; XIA ZhiXun; LIU Bing; DENG Xiong

    2012-01-01

    Actuators are one of the key points for the development of active flow control technology.Efficient methods of high speed flow control can provide enhanced propulsive efficiency and at the same time enable safe and maneuverable high speed flight.The development of high speed flight technology promotes the emergence of novel and robust actuators.This review introduces the state of the art in the development of actuators that can be used in high speed active flow control.The classification and different operation criteria of the actuators are discussed.The specifications,mechanisms and applications of various popular actuator types including fluidic,mechanical,and plasma actuators are described.Based on the realistic need of high speed flow control and the existing results of actuators,a new actuator design method is proposed.At last,the merits and drawbacks of the actuators are summarized and some suggestions on the development of active flow control technology are put forward.

  13. Ping-Pong Robotics with High-Speed Vision System

    DEFF Research Database (Denmark)

    Li, Hailing; Wu, Haiyan; Lou, Lei

    2012-01-01

    , a multithreshold legmentation algorithm is applied in a stereo-vision running at 150Hz. Based on the estimated 3D ball positions, a novel two-phase trajectory prediction is exploited to determine the hitting position. Benefiting from the high-speed visual feedback, the hitting position and thus the motion planning......The performance of vision-based control is usually limited by the low sampling rate of the visual feedback. We address Ping-Pong robotics as a widely studied example which requires high-speed vision for highly dynamic motion control. In order to detect a flying ball accurately and robustly...

  14. Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ding Youliang

    2016-01-01

    Full Text Available Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

  15. Estimation of extreme wind speeds in the mixed strong wind climate of South Africa

    CSIR Research Space (South Africa)

    Kruger, AC

    2010-08-01

    Full Text Available The South African Weather Service, with the support of the Council for Scientific and Industrial Research (CSIR) and the University of Stellenbosch, is in the process of updating the extreme surface wind statistics for South Africa. A previous...

  16. Research on Aerodynamic Noise Reduction for High-Speed Trains

    Directory of Open Access Journals (Sweden)

    Yadong Zhang

    2016-01-01

    Full Text Available A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES using the finite volume method with high-order difference schemes. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD/Ffowcs Williams-Hawkings (FW-H acoustic analogy. An analysis of noise reduction methods based on the main noise sources was performed. An aerodynamic noise model for a full-scale high-speed train, including three coaches with six bogies, two inter-coach spacings, two windscreen wipers, and two pantographs, was established. Several low-noise design improvements for the high-speed train were identified, based primarily on the main noise sources; these improvements included the choice of the knuckle-downstream or knuckle-upstream pantograph orientation as well as different pantograph fairing structures, pantograph fairing installation positions, pantograph lifting configurations, inter-coach spacings, and bogie skirt boards. Based on the analysis, we designed a low-noise structure for a full-scale high-speed train with an average sound pressure level (SPL 3.2 dB(A lower than that of the original train. Thus, the noise reduction design goal was achieved. In addition, the accuracy of the aerodynamic noise calculation method was demonstrated via experimental wind tunnel tests.

  17. MARVIN : high speed 3D imaging for seedling classification

    NARCIS (Netherlands)

    Koenderink, N.J.J.P.; Wigham, M.L.I.; Golbach, F.B.T.F.; Otten, G.W.; Gerlich, R.J.H.; Zedde, van de H.J.

    2009-01-01

    The next generation of automated sorting machines for seedlings demands 3D models of the plants to be made at high speed and with high accuracy. In our system the 3D plant model is created based on the information of 24 RGB cameras. Our contribution is an image acquisition technique based on

  18. Adaptations to speed endurance training in highly trained soccer players

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Fiorenza, Matteo; Lund, Anders

    2016-01-01

    PURPOSE: The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I...... and II muscle fibers. METHODS: During the last nine weeks of the season, thirteen semi-professional soccer players performed additional speed endurance training sessions consisting of 2-3 sets of 8 - 10 repetitions of 30 m sprints with 10 s of passive recovery (SET). Before and after SET, subjects...... in type I and II fibers did not change. CONCLUSION: In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V˙O2 kinetics and mechanical efficiency in type I fibers...

  19. Extreme states of matter high energy density physics

    CERN Document Server

    Fortov, Vladimir E

    2016-01-01

    With its many beautiful colour pictures, this book gives fascinating insights into the unusual forms and behaviour of matter under extremely high pressures and temperatures. These extreme states are generated, among other things, by strong shock, detonation and electric explosion waves, dense laser beams,electron and ion beams, hypersonic entry of spacecraft into dense atmospheres of planets, and in many other situations characterized by extremely high pressures and temperatures.Written by one of the world's foremost experts on the topic, this book will inform and fascinate all scientists dealing with materials properties and physics, and also serve as an excellent introduction to plasma-, shock-wave and high-energy-density physics for students and newcomers seeking an overview. This second edition is thoroughly revised and expanded, in particular with new material on high energy-density physics, nuclear explosions and other nuclear transformation processes.

  20. VCA Direct-Drive High Speed and Precision XY Table

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xingyu; FENG Xiaomei; ZHANG Dawei

    2007-01-01

    In order to compensate for the limitation of conventional XY table used in semiconductor integrated circuits(IC) packaging and improve its speed and accuracy, a voice coil actuator (VCA)direct-drive high-speed and precision positioning XY table used in wire bonder was proposed. Also, a novel flexible decoupling mechanism was used in the positioning table, and the small moving mass enabled the positioning table to move at high speed and precision. XY table deformation interference caused by assembly error and instant interference generated by dynamic load moving with high speed and acceleration can be eliminated through the flexible decoupling mechanism. Considering the positioning table as lumped mass spring system, the dynamic equations of the mechanical sys-tem and the VCA were built according to the Newton mechanics principle and electromagnetic theory. Then the electromechanical coupling control model of the system was created through Laplace transform. Based on displacement PID controller, the Icop-locked controlling algorithm of the positioning system was investigated. The dynamic control algorithm effectively improved the system dynamic performance. The precision test of the prototype machine was carried out, and the results val-idated the correctness of the model and the theory. Compared with traditional XY table, the tablehas higher speed, acceleration and positioning accuracy.

  1. High Pressure Sensing and Dynamics Using High Speed Fiber Bragg Grating Interrogation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, G. [LANL; Sandberg, R. L. [LANL; Lalone, B. M. [NSTec; Marshall, B. R. [NSTec; Grover, M. [NSTec; Stevens, G. D. [NSTec; Udd, E. [Columbia Gorge Research

    2014-06-01

    Fiber Bragg gratings (FBGs) are developing into useful sensing tools for measuring high pressure dynamics in extreme environments under shock loading conditions. Approaches using traditional diode array coupled FBG interrogation systems are often limited to readout speeds in the sub-MHz range. For shock wave physics, required detection speeds approaching 100 MHz are desired. We explore the use of two types of FBG sensing systems that are aimed at applying this technology as embedded high pressure probes for transient shock events. Both approaches measure time resolved spectral shifts in the return light from short (few mm long) uniform FBGs at 1550 nm. In the first approach, we use a fiber coupled spectrometer to demultiplex spectral channels into an array (up to 12) of single element InGaAs photoreceivers. By monitoring the detectors during a shock impact event with high speed recording, we are able to track the pressure induced spectral shifting in FBG down to a time resolution of 20 ns. In the second approach, developed at the Special Technologies Lab, a coherent mode-locked fiber laser is used to illuminate the FBG sensor. After the sensor, wavelength-to-time mapping is accomplished with a chromatic dispersive element, and entire spectra are sampled using a single detector at the modelocked laser repetition rate of 50 MHz. By sampling with a 12 GHz InGaAs detector, direct wavelength mapping in time is recorded, and the pressure induced FBG spectral shift is sampled at 50 MHz. Here, the sensing systems are used to monitor the spectral shifts of FBGs that are immersed into liquid water and shock compressed using explosives. In this configuration, the gratings survive to pressures approaching 50 kbar. We describe both approaches and present the measured spectral shifts from the shock experiments.

  2. High Speed, Low Power Current Comparators with Hysteresis

    Directory of Open Access Journals (Sweden)

    Neeraj K. Chasta

    2012-02-01

    Full Text Available This paper, presents a novel idea for analog current comparison which compares input signal current and reference currents with high speed, low power and well controlled hysteresis. Proposed circuit is based on current mirror and voltage latching techniques which produces rail to rail output voltage as a result of current comparison. The same design can be extended to a simple current comparator without hysteresis (or very less hysteresis, where comparator gives high accuracy (less than 50nA and speed at the cost of moderate power consumption. The comparators are designed optimally and studied at 180 nm CMOS process technology for a supply voltage of 3V.

  3. High Speed, Low Power Current Comparators with Hysteresis

    Directory of Open Access Journals (Sweden)

    Neeraj K. Chasta

    2012-03-01

    Full Text Available This paper, presents a novel idea for analog current comparison which compares input signal current and reference currents with high speed, low power and well controlled hysteresis. Proposed circuit is based on current mirror and voltage latching techniques which produces rail to rail output voltage as a result of current comparison. The same design can be extended to a simple current comparator without hysteresis (or very less hysteresis, where comparator gives high accuracy (less than 50nA and speed at the cost of moderate power consumption. The comparators are designed optimally and studied at 180nm CMOS process technology for a supply voltage of 3V.

  4. Method for high-speed Manchester encoded optical signal generation

    DEFF Research Database (Denmark)

    Zhang, Jianfeng; Chi, Nan; Holm-Nielsen, Pablo Villanueva

    2004-01-01

    A method for high-speed Manchester encoded optical signal generation is proposed and demonstrated with a specially configured electro-optical modulator. A 10 Gb/s Manchester encoded optical signal was generated, and its bit-error-ratio (BER) performance was evaluated.......A method for high-speed Manchester encoded optical signal generation is proposed and demonstrated with a specially configured electro-optical modulator. A 10 Gb/s Manchester encoded optical signal was generated, and its bit-error-ratio (BER) performance was evaluated....

  5. Necking Point in PET High-speed Fiber Spinning

    Institute of Scientific and Technical Information of China (English)

    王夏琴; 唐志廉

    2001-01-01

    Cross-over method is established to predict necking point for PET high- speed fiber spinning. Even slowly crystallizing polymers such as PET can crystallize on the spinline at sufficiently high spinning speed. The development of rtmning velocity, temperature, crystallinity and theological force is investigated for the take-up velocity over a range of 6 000 - 10 000 m/min. The position of necking point, temperature rise and abrupt increase of crystallinity move closer to the spinneret with the increase of take-up velocity,

  6. High Speed, Low Power Current Comparators with Hysteresis

    CERN Document Server

    Chasta, Neeraj K

    2012-01-01

    This paper, presents a novel idea for analog current comparison which compares input signal current and reference currents with high speed, low power and well controlled hysteresis. Proposed circuit is based on current mirror and voltage latching techniques which produces rail to rail output voltage as a result of current comparison. The same design can be extended to a simple current comparator without hysteresis (or very less hysteresis), where comparator gives high accuracy (less than 50nA) and speed at the cost of moderate power consumption. The comparators are designed optimally and studied at 180nm CMOS process technology for a supply voltage of 3V.

  7. Miniature high speed compressor having embedded permanent magnet motor

    Science.gov (United States)

    Zhou, Lei (Inventor); Zheng, Liping (Inventor); Chow, Louis (Inventor); Kapat, Jayanta S. (Inventor); Wu, Thomas X. (Inventor); Kota, Krishna M. (Inventor); Li, Xiaoyi (Inventor); Acharya, Dipjyoti (Inventor)

    2011-01-01

    A high speed centrifugal compressor for compressing fluids includes a permanent magnet synchronous motor (PMSM) having a hollow shaft, the being supported on its ends by ball bearing supports. A permanent magnet core is embedded inside the shaft. A stator with a winding is located radially outward of the shaft. The PMSM includes a rotor including at least one impeller secured to the shaft or integrated with the shaft as a single piece. The rotor is a high rigidity rotor providing a bending mode speed of at least 100,000 RPM which advantageously permits implementation of relatively low-cost ball bearing supports.

  8. Improvement of die life in high speed injection die casting

    Institute of Scientific and Technical Information of China (English)

    Yasuhiro Arisuda; Akihito Hasuno; Junji Yoshida; Kazunari Tanii

    2008-01-01

    High-speed injection die casting is an efficient manufacturing technology for upgrading aluminum die-cast products. However, deficiencies (such as die damage in eady period) due to larger load on the molding die compared with conventional technology have brought new challenges. In this study, the cause of damage generated in super high-speed injection was investigated by the combination of experimental observation of the dies and CAE simulation (e.g. die temperature analysis, flow analysis and thermal stress analysis). The potential countermeasures to solve the above problems were also proposed.

  9. Improvement of die life in high speed injection die casting

    Directory of Open Access Journals (Sweden)

    Akihito Hasuno

    2008-11-01

    Full Text Available High-speed injection die casting is an effi cient manufacturing technology for upgrading aluminum die-cast products. However, defi ciencies (such as die damage in early period due to larger load on the molding die compared with conventional technology have brought new challenges. In this study, the cause of damage generated in super high-speed injection was investigated by the combination of experimental observation of the dies and CAE simulation (e.g. die emperature analysis, fl ow analysis and thermal stress analysis. The potential countermeasures to solve the above problems were also proposed.

  10. Compact Models and Measurement Techniques for High-Speed Interconnects

    CERN Document Server

    Sharma, Rohit

    2012-01-01

    Compact Models and Measurement Techniques for High-Speed Interconnects provides detailed analysis of issues related to high-speed interconnects from the perspective of modeling approaches and measurement techniques. Particular focus is laid on the unified approach (variational method combined with the transverse transmission line technique) to develop efficient compact models for planar interconnects. This book will give a qualitative summary of the various reported modeling techniques and approaches and will help researchers and graduate students with deeper insights into interconnect models in particular and interconnect in general. Time domain and frequency domain measurement techniques and simulation methodology are also explained in this book.

  11. Magneto-optical system for high speed real time imaging

    Science.gov (United States)

    Baziljevich, M.; Barness, D.; Sinvani, M.; Perel, E.; Shaulov, A.; Yeshurun, Y.

    2012-08-01

    A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

  12. Microstructural development and mechanical properties of high speed steels

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, A.; Gordo, E.; Velasco, F.; Candela, N.; Torralba, J.M. [Dept. de Ciencia de Materiales e Ing. Metalurgica, Univ. Carlos III de Madrid (Spain)

    2001-07-01

    A study was made of the sintering of high speed steel (HSS), M3/2, with different percentage additions - (0%, 2.5%, 5% and 8% by vol.) - of niobium carbide. The mixture was ground in a high speed ball mill to ensure smooth distribution and a material free from agglomerates. All the mixtures were sintered at temperatures above that of solidus, higher temperatures being required as the proportion of the niobium carbide was increased. The variation of the density and hardness were measured, as well as the evolution of the microstructure and the composition of the carbides with the sintering temperature. (orig.)

  13. Plasma-Assisted Chemistry in High-Speed Flow

    Institute of Scientific and Technical Information of China (English)

    Sergey B.LEONOV; Dmitry A.YARANTSEV; Anatoly P.NAPARTOVICH; Igor V.KOCHETOV

    2007-01-01

    Fundamental problems related to the high-speed combustion are analyzed. The result of plasma-chemical modeling is presented as a motivation of experimental activity.Numerical simulations of the effect of uniform non-equilibrium discharge on the premixed hydrogen and ethylene-air mixture in supersonic flow demonstrate an advantage of such a technique over a heating.Experimental results on multi-electrode non-uniform discharge maintenance behind wallstep and in cavity of supersonic flow are presented.The model test on hydrogen and ethylene ignition is demonstrated at direct fuel injection to low-temperature high-speed airflow.

  14. Gait Transitions in Human Infants: Coping with Extremes of Treadmill Speed.

    Directory of Open Access Journals (Sweden)

    Erin V Vasudevan

    Full Text Available Spinal pattern generators in quadrupedal animals can coordinate different forms of locomotion, like trotting or galloping, by altering coordination between the limbs (interlimb coordination. In the human system, infants have been used to study the subcortical control of gait, since the cerebral cortex and corticospinal tract are immature early in life. Like other animals, human infants can modify interlimb coordination to jump or step. Do human infants possess functional neuronal circuitry necessary to modify coordination within a limb (intralimb coordination in order to generate distinct forms of alternating bipedal gait, such as walking and running? We monitored twenty-eight infants (7-12 months stepping on a treadmill at speeds ranging between 0.06-2.36 m/s, and seventeen adults (22-47 years walking or running at speeds spanning the walk-to-run transition. Six of the adults were tested with body weight support to mimic the conditions of infant stepping. We found that infants could accommodate a wide range of speeds by altering stride length and frequency, similar to adults. Moreover, as the treadmill speed increased, we observed periods of flight during which neither foot was in ground contact in infants and in adults. However, while adults modified other aspects of intralimb coordination and the mechanics of progression to transition to a running gait, infants did not make comparable changes. The lack of evidence for distinct walking and running patterns in infants suggests that the expression of different functional, alternating gait patterns in humans may require neuromuscular maturation and a period of learning post-independent walking.

  15. High-speed wavefront modulation in complex media (Conference Presentation)

    Science.gov (United States)

    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.

  16. Ultra-high-speed optical and electronic distributed devices

    Energy Technology Data Exchange (ETDEWEB)

    Hietala, V.M.; Plut, T.A.; Kravitz, S.H.; Vawter, G.A.; Wendt, J.R.; Armendariz, M.G.

    1995-08-01

    This report summarizes work on the development of ultra-high-speed semiconductor optical and electronic devices. High-speed operation is achieved by velocity matching the input stimulus to the output signal along the device`s length. Electronic devices such as field-effect transistors (FET`s), should experience significant speed increases by velocity matching the electrical input and output signals along the device. Likewise, optical devices, which are typically large, can obtain significant bandwidths by velocity matching the light being generated, detected or modulated with the electrical signal on the device`s electrodes. The devices discussed in this report utilize truly distributed electrical design based on slow-wave propagation to achieve velocity matching.

  17. High-speed pulse-shape generator, pulse multiplexer

    Science.gov (United States)

    Burkhart, Scott C.

    2002-01-01

    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  18. TCP-Adaptive in High Speed Long Distance Networks

    Directory of Open Access Journals (Sweden)

    Quan Liu

    2014-02-01

    Full Text Available With the development of high performance computing and increasing of network bandwidth, more and more applications require fast data transfer over high-speed long-distance networks. Research shows that the standard TCP Reno cannot fulfill the requirement of fast transfer of massive data due to its conservative congestion control mechanism. Some works have been proposed to improve the TCP throughput performance using more aggressive window increasing tactics and obtain substantial achievements. However, they cannot be strictly proved to be comprehensively suitable for high-speed complex network environments. In this paper, we propose TCP-Adaptive, an adaptive congestion control algorithm adjusting the increasing congestion window dynamically. The algorithm improves logarithmic detection procedure for available bandwidth in the flow path by distinguishing the first detection in congestion avoidance and retransmission timeout. On the other hand, an adaptive control algorithm is proposed to achieve better performance in high-speed long-distance networks. The algorithm uses round trip time (RTT variations to predict the congestion trends to update the increments of congestion window. Simulations verify the property of TCP-Adaptive and show satisfying performance in throughput, RTT fairness aspects over high-speed long-distance networks. Especially in sporadic loss environment, TCP-Adaptive shows a significant adaptability with the variations of link quality

  19. High-speed traveling-wave electro-absorption modulators

    Science.gov (United States)

    Westergren, Urban; Yu, Yichuan; Thylén, Lars

    2006-07-01

    Electroabsorption modulators (EAM) based on quantum-confined Stark effect (QCSE) in multiplequantum wells (MQW) have been demonstrated to provide high-speed, low drive voltage, and high extinction ratio. They are compact in size and can be monolithically integrated with continuous-wave (CW) lasers. In order to achieve both high speed and low drive-voltage operation, travelling-wave (TW) electrode structures can be used for EAMs. The inherently low impedance of high-speed EAMs may be transformed to values close to the standard 50Ohm impedance using periodic microwave structures with a combination of passive transmission lines with high characteristic impedance and active modulator sections with low impedance. Modulation bandwidths of 100GHz (-3dBe) have been accomplished with electrical reflections lower than -10dB in a 50Ohm system. Transmission at 80Gbit/s with non-return-to-zero (NRZ) code has been demonstrated for InP-based TWEAMs using electronic time-domain multiplexing (ETDM), indicating the possibility of reaching speeds of 100Gbit/s and beyond.

  20. Strain rate effect in high-speed wire drawing process

    Science.gov (United States)

    He, S.; Van Houtte, P.; Van Bael, A.; Mei, F.; Sarban, A.; Boesman, P.; Galvez, F.; Atienza, J. M.

    2002-05-01

    This paper presents a study on the strain rate effect during high-speed wire drawing process by means of finite element simulation. Based on the quasistatic stresses obtained by normal tensile tests and dynamic stresses at high strain rates by split Hopkinson pressure bar tests, the wire drawing process was simulated for low carbon steel and high carbon steel. The results show that both the deformation process and the final properties of drawn wires are influenced by the strain rate.

  1. Extremely High Q-factor metamaterials due to Anapole Excitation

    CERN Document Server

    Basharin, Alexey A; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N

    2016-01-01

    We demonstrate that ideal anapole metamaterials have infinite Q-factor. We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit anapole behavior in the sense that the electric dipole radiation is almost cancelled by the toroidal dipole one, producing thus an extremely high Q-factor at the resonance frequency. The size of the system, at the mm range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q-factor. In spite of the very low radiation losses the local fields at the metamolecules are extremely high, of the order of higher than the external incoming field.

  2. Investigation of the effects of sleeper-passing impacts on the high-speed train

    Science.gov (United States)

    Wu, Xingwen; Cai, Wubin; Chi, Maoru; Wei, Lai; Shi, Huailong; Zhu, Minhao

    2015-12-01

    The sleeper-passing impact has always been considered negligible in normal conditions, while the experimental data obtained from a High-speed train in a cold weather expressed significant sleeper-passing impacts on the axle box, bogie frame and car body. Therefore, in this study, a vertical coupled vehicle/track dynamic model was developed to investigate the sleeper-passing impacts and its effects on the dynamic performance of the high-speed train. In the model, the dynamic model of vehicle is established with 10 degrees of freedom. The track model is formulated with two rails supported on the discrete supports through the finite element method. The contact forces between the wheel and rail are estimated using the non-linear Hertz contact theory. The parametric studies are conducted to analyse effects of both the vehicle speeds and the discrete support stiffness on the sleeper-passing impacts. The results show that the sleeper-passing impacts become extremely significant with the increased support stiffness of track, especially when the frequencies of sleeper-passing impacts approach to the resonance frequencies of wheel/track system. The damping of primary suspension can effectively lower the magnitude of impacts in the resonance speed ranges, but has little effect on other speed ranges. Finally, a more comprehensively coupled vehicle/track dynamic model integrating with a flexible wheel set is developed to discuss the sleeper-passing-induced flexible vibration of wheel set.

  3. Toward high-speed access technologies: results from MUSE

    Science.gov (United States)

    Wellen, Jeroen; Smets, Rob; Hellenthal, Wim; Lepley, Jason; Tsalamanis, Ioannis; Walker, Stuart; Ng'oma, Anthony; Rijckenberg, Gert-Jan; Koonen, Ton; Habel, Kai; Langer, Klaus-Dieter

    2006-10-01

    The European MUSE project, which aims to enable "MUlti Service and access Everywhere", studies architectures, technologies and business scenarios facilitating the deployment of new Broadband Access Networks and Services. This paper gives an overview and particularly discusses results of some of the high-speed access technologies that are developed.

  4. Size Reduction of Tunable Micromachined Filters for High Speed Operations

    Institute of Scientific and Technical Information of China (English)

    Tomoyuki; Hino; Takeru; Amano; Wiganes; Janto; Fumio; Koyama

    2003-01-01

    The size reduction of tunable micromachined filters is carried out for high-speed wavelength tuning. We fabricated micromachined filters having a miniature structure with an air gap of 300 run and a short cantilever of 45 urn, exhibiting fast response of below 3 us.

  5. Size Reduction of Tunable Micromachined Filters for High Speed Operations

    Institute of Scientific and Technical Information of China (English)

    Tomoyuki Hino; Takeru Amano; Wiganes Janto; Fumio Koyama

    2003-01-01

    The size reduction of tunable micromachined filters is carried out for high-speed wavelength tuning. We fabricated micromachined filters having a miniature structure with an air gap of 300 nm and a short cantilever of 45 μm, exhibiting fast response of below 3 μs.

  6. APPLICATION OF POWDER HIGH-SPEED STEEL AS ANTIFRICTION MATERIAL

    Directory of Open Access Journals (Sweden)

    M. Beznak

    2011-01-01

    Full Text Available The influence of disulphide molybdenum additives on antifriction characteristics of powder high-speed steel produced by means of hot hydrostatic pressing is investigated. It is shown that disulphide molybdenum additives promote the decrease of coefficient of friction and temperature in hearth of friction as a result the increase of wear resistance of steel.

  7. Modelling Of Residual Stresses Induced By High Speed Milling Process

    Science.gov (United States)

    Desmaison, Olivier; Mocellin, Katia; Jardin, Nicolas

    2011-05-01

    Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction. Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge® software, is based on data taken from Outeiro & al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature. Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R&D to those given by numerical simulations is achieved.

  8. Minimum Plate Thickness in High-Speed Craft

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    The minimum plate thickness requirements specified by the classification societies for high-speed craft are supposed to ensure adequate resistance to impact loads such as collision with floating objects and objects falling on the deck. The paper presents analytical methods of describing such impact...

  9. Exploring THz band for high speed wireless communications

    DEFF Research Database (Denmark)

    Yu, Xianbin; Zhang, Hangkai; Jia, Shi;

    2016-01-01

    We overview recent trend in developing high speed wireless communication systems by exploring large bandwidth available in the THz band, and we also present our recent experimental achievements on 400 GHz wireless transmission with a data rate of up to 60 Gbit/s by using a uni-travelling carrier...

  10. High Speed Lunar Navigation for Crewed and Remotely Piloted Vehicles

    Science.gov (United States)

    Pedersen, L.; Allan, M.; To, V.; Utz, H.; Wojcikiewicz, W.; Chautems, C.

    2010-01-01

    Increased navigation speed is desirable for lunar rovers, whether autonomous, crewed or remotely operated, but is hampered by the low gravity, high contrast lighting and rough terrain. We describe lidar based navigation system deployed on NASA's K10 autonomous rover and to increase the terrain hazard situational awareness of the Lunar Electric Rover crew.

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

    Science.gov (United States)

    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-Frequency Technical Trading: The Importance of Speed

    NARCIS (Netherlands)

    M.L. Scholtus (Martin); D.J.C. van Dijk (Dick)

    2012-01-01

    textabstractThis paper investigates the importance of speed for technical trading rule performance for three highly liquid ETFs listed on NASDAQ over the period January 6, 2009 up to September 30, 2009. In addition we examine the characteristics of market activity over the day and within subperiods

  13. Intel Legend and CERN would build up high speed Internet

    CERN Multimedia

    2002-01-01

    Intel, Legend and China Education and Research Network jointly announced on the 25th of April that they will be cooperating with each other to build up the new generation high speed internet, over the next three years (1/2 page).

  14. High Speed Rail (HSR) in the United States

    Science.gov (United States)

    2009-12-08

    passenger rail service, while trying to help rail 25 Available at http://www.fomento.es/MFOMWeb/ paginas ...Offers Guideposts for U.S.,” The New York Times On the Web , May 30, 2009. High Speed Rail (HSR) in the United States Congressional Research

  15. Recent Advances in Ultra-High-Speed Optical Signal Processing

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Hu, Hao;

    2012-01-01

    We review recent advances in the optical signal processing of ultra-high-speed serial data signals up to 1.28 Tbit/s, with focus on applications of time-domain optical Fourier transformation. Experimental methods for the generation of symbol rates up to 1.28 Tbaud are also described....

  16. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    OpenAIRE

    Shih-Chen Shi; Chieh-Chang Su

    2016-01-01

    The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate prom...

  17. Characterising argon-bomb balloons for high-speed photography

    CSIR Research Space (South Africa)

    Olivier, M

    2013-08-01

    Full Text Available A method to optimise the geometry, explosive charge mass and volume of an argon bomb for specific lighting requirements has been proposed. The method is specifically aimed at applications that require photographic diagnostics with ultra-high speed...

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

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter

    2012-01-01

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

  19. Research and practice: The European High Speed Station

    NARCIS (Netherlands)

    Triggianese, M.

    2014-01-01

    The practices of planning and architecture are undergoing considerable transformation especially for urban developments asso-ciated to infrastructural changes. This paper considers the proliferation of high-speed railways in Europe as a research opportunity to better understand the practice of compl

  20. Towards a high-speed quantum random number generator

    Science.gov (United States)

    Stucki, Damien; Burri, Samuel; Charbon, Edoardo; Chunnilall, Christopher; Meneghetti, Alessio; Regazzoni, Francesco

    2013-10-01

    Randomness is of fundamental importance in various fields, such as cryptography, numerical simulations, or the gaming industry. Quantum physics, which is fundamentally probabilistic, is the best option for a physical random number generator. In this article, we will present the work carried out in various projects in the context of the development of a commercial and certified high speed random number generator.

  1. Modeling of high speed micro rotors in moderate flow confinement

    NARCIS (Netherlands)

    Dikmen, E.; Hoogt, van der P.J.M.; Aarts, R.G.K.M.

    2008-01-01

    The recent developments in high speed micro rotating machinery lead to the need for multiphysical modeling of the rotor and the surrounding medium. In this study, thermal and flow induced effects on rotor dynamics of geometries with moderate flow confinement are studied. The structure is modeled via

  2. Design criteria for light high speed desert air cushion vehicles

    Science.gov (United States)

    Abulnaga, B. E.

    An evaluation is made of the applicability and prospective performance of ACVs in trans-Saharan cargo transport, in view of the unique characteristics of the dry sand environment. The lightweight/high-speed ACV concept envisioned is essentially ground effect aircraftlike, with conventional wheels as a low-speed backup suspension system. A propeller is used in ground effect cruise. Attention is given to the effects on vehicle stability and performance of sandy surface irregularities of the desert topography and of cross-winds from various directions relative to vehicle movement.

  3. Study on High-Speed Magnitude Approximation for Complex Vectors

    Institute of Scientific and Technical Information of China (English)

    陈建春; 杨万海; 许少英

    2003-01-01

    High-speed magnitude approximation algorithms for complex vectors are discussed intensively. The performance and the convergence speed of these approximation algorithms are analyzed. For the polygon fitting algorithms, the approximation formula under the least mean square error criterion is derived. For the iterative algorithms, a modified CORDIC (coordinate rotation digital computer) algorithm is developed. This modified CORDIC algorithm is proved to be with a maximum relative error about one half that of the original CORDIC algorithm. Finally, the effects of the finite register length on these algorithms are also concerned, which shows that 9 to 12-bit coefficients are sufficient for practical applications.

  4. Development of small bore, high speed tapered roller bearing

    Science.gov (United States)

    Morrison, F. R.; Gassel, S. S.; Bovenkerk, R. L.

    1981-01-01

    The performance of four rolling bearing configurations for use on the input pinion shaft of a proposed commercial helicopter transmission was evaluated. The performance characteristics of a high speed tapered roller bearing operating under conditions comparable to those existing at this input pinion shaft were defined. The tapered roller bearing shaft support configuration was developed for the gearbox using commercially available bearing designings. The configuration was optimized and interactive thermomechanically system analyzed. Automotive pinion quality tapered roller bearings were found to be reliable under load and speed conditions in excess of those anticipated in the helicopter transmission. However, it is indicated that the elastohydrodynamic lubricant films are inadequate.

  5. Research of high speed optical switch based on compound semiconductor

    Institute of Scientific and Technical Information of China (English)

    WANG MingHua; QI Wei; YU Hui; JIANG XiaoQing; YANG JianYi

    2009-01-01

    High-speed optical switch and its array are the crucial components of all-optical switching system. This paper presents the analytical model of a total-internal-reflection (TIR) optical switch. By employing the carrier injection effect in GaAs and the GaAs/AlGaAs double heterojunction structure, the X-junction TIR switch and the Mach-Zehnder interference (MZI) switch are demonstrated at 1.55 IJm. The measured results show that the extinction ratio of both switches exceeds 20 dB. The switching speed reaches the scale of 10 ns.

  6. Design of a high speed rotating mechanical shutter

    Energy Technology Data Exchange (ETDEWEB)

    Stowers, I.F.; Merritt, B.T.; McFann, C.B.

    1979-11-06

    A high-speed rotating shutter was designed to operate in a 10/sup -6/ Torr vacuum at the optical focus of a laser spatial filter. The shutter is basically a wheel, with a single 3 x 10-mm slot at the perimeter, which rotates with a peripheral speed of 1 km/s. The motor to drive the rotating wheel is magnetically suspended and synchronously wound. The wheel achieves a 4 ..mu..s opening time and a timing accuracy of better than 0.2 ..mu..s. (MOW)

  7. High-Speed Low Power Design in CMOS

    DEFF Research Database (Denmark)

    Ghani, Arfan; Usmani, S. H.; Stassen, Flemming

    2004-01-01

    Static CMOS design displays benefits such as low power consumption, dominated by dynamic power consumption. In contrast, MOS Current Mode Logic (MCML) displays static rather than dynamic power consumption. High-speed low-power design is one of the many application areas in VLSI that require...... the appropriate domains of performance and power requirements in which MCML presents benefits over standard CMOS. An optimized cell library is designed and implemented in both CMOS and MCML in order to make a comparison with reference to speed and power. Much more time is spent in order to nderstand...

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

    Science.gov (United States)

    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.

  9. Design the High Speed Kogge-Stone Adder by Using

    Directory of Open Access Journals (Sweden)

    MUX

    2015-08-01

    Full Text Available In this Technical era the high speed and low area of VLSI chip are very- very essential factors. Day by day number of transistors and other active and passive elements are growing on VLSI chip. In Integral part of the processor adders play an important role. In this paper we are using proposed kogge-stone adders for binary addition to reduce the size and increase the efficiency or processors speed. Proposing kogge stone adder provides less components, less path delay and better speed compare to other existing kogge stone adder and other adders. Here we are comparing the kogge stone adders of different-different word size from other adders. The design and experiment can be done by the aid of Xilinx 14.1i Spartan 3 device family.

  10. Extremely high-power tongue projection in plethodontid salamanders

    NARCIS (Netherlands)

    Deban, S.M.; O'Reilly, J.C.; Dicke, U.; Leeuwen, van J.L.

    2007-01-01

    Many plethodontid salamanders project their tongues ballistically at high speed and for relatively great distances. Capturing evasive prey relies on the tongue reaching the target in minimum time, therefore it is expected that power production, or the rate of energy release, is maximized during tong

  11. Numerical simulation of high speed incremental forming of aluminum alloy

    Science.gov (United States)

    Giuseppina, Ambrogio; Teresa, Citrea; Luigino, Filice; Francesco, Gagliardi

    2013-12-01

    In this study, an innovative process is analyzed with the aim to satisfy the industrial requirements, such as process flexibility, differentiation and customizing of products, cost reduction, minimization of execution time, sustainable production, etc. The attention is focused on incremental forming process, nowadays used in different fields such as: rapid prototyping, medical sector, architectural industry, aerospace and marine, in the production of molds and dies. Incremental forming consists in deforming only a small region of the workspace through a punch driven by a NC machine. SPIF is the considered variant of the process, in which the punch gives local deformation without dies and molds; consequently, the final product geometry can be changed by the control of an actuator without requiring a set of different tools. The drawback of this process is its slowness. The aim of this study is to assess the IF feasibility at high speeds. An experimental campaign will be performed by a CNC lathe with high speed to test process feasibility and the influence on materials formability mainly on aluminum alloys. The first results show how the material presents the same performance than in conventional speed IF and, in some cases, better material behavior due to the temperature field. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process substantially confirming experimental evidence.

  12. Sound transmission loss of windows on high speed trains

    Science.gov (United States)

    Zhang, Yumei; Xiao, Xinbiao; Thompson, David; Squicciarini, Giacomo; Wen, Zefeng; Li, Zhihui; Wu, Yue

    2016-09-01

    The window is one of the main components of the high speed train car body structure through which noise can be transmitted. To study the windows’ acoustic properties, the vibration of one window of a high speed train has been measured for a running speed of 250 km/h. The corresponding interior noise and the noise in the wheel-rail area have been measured simultaneously. The experimental results show that the window vibration velocity has a similar spectral shape to the interior noise. Interior noise source identification further indicates that the window makes a contribution to the interior noise. Improvement of the window's Sound Transmission Loss (STL) can reduce the interior noise from this transmission path. An STL model of the window is built based on wave propagation and modal superposition methods. From the theoretical results, the window's STL property is studied and several factors affecting it are investigated, which provide indications for future low noise design of high speed train windows.

  13. High speed intravascular photoacoustic imaging of atherosclerotic arteries (Conference Presentation)

    Science.gov (United States)

    Piao, Zhonglie; Ma, Teng; Qu, Yueqiao; Li, Jiawen; Yu, Mingyue; He, Youmin; Shung, K. Kirk; Zhou, Qifa; Kim, Chang-Seok; Chen, Zhongping

    2016-02-01

    Cardiovascular disease is the leading cause of death in the industrialized nations. Accurate quantification of both the morphology and composition of lipid-rich vulnerable atherosclerotic plaque are essential for early detection and optimal treatment in clinics. In previous works, intravascular photoacoustic (IVPA) imaging for detection of lipid-rich plaque within coronary artery walls has been demonstrated in ex vivo, but the imaging speed is still limited. In order to increase the imaging speed, a high repetition rate laser is needed. In this work, we present a high speed integrated IVPA/US imaging system with a 500 Hz optical parametric oscillator laser at 1725 nm. A miniature catheter with 1.0 mm outer diameter was designed with a 200 μm multimode fiber and an ultrasound transducer with 45 MHz center frequency. The fiber was polished at 38 degree and enclosed in a glass capillary for total internal reflection. An optical/electrical rotary junction and pull-back mechanism was applied for rotating and linearly scanning the catheter to obtain three-dimensional imaging. Atherosclerotic rabbit abdominal aorta was imaged as two frame/second at 1725 nm. Furthermore, by wide tuning range of the laser wavelength from 1680 nm to 1770 nm, spectroscopic photoacoustic analysis of lipid-mimicking phantom and an human atherosclerotic artery was performed ex vivo. The results demonstrated that the developed IVPA/US imaging system is capable for high speed intravascular imaging for plaque detection.

  14. Differences in energy expenditure during high-speed versus standard-speed yoga: A randomized sequence crossover trial.

    Science.gov (United States)

    Potiaumpai, Melanie; Martins, Maria Carolina Massoni; Rodriguez, Roberto; Mooney, Kiersten; Signorile, Joseph F

    2016-12-01

    To compare energy expenditure and volume of oxygen consumption and carbon dioxide production during a high-speed yoga and a standard-speed yoga program. Randomized repeated measures controlled trial. A laboratory of neuromuscular research and active aging. Sun-Salutation B was performed, for eight minutes, at a high speed versus and a standard-speed separately while oxygen consumption was recorded. Caloric expenditure was calculated using volume of oxygen consumption and carbon dioxide production. Difference in energy expenditure (kcal) of HSY and SSY. Significant differences were observed in energy expenditure between yoga speeds with high-speed yoga producing significantly higher energy expenditure than standard-speed yoga (MD=18.55, SE=1.86, pyoga for volume of oxygen consumed and carbon dioxide produced. High-speed yoga results in a significantly greater caloric expenditure than standard-speed yoga. High-speed yoga may be an effective alternative program for those targeting cardiometabolic markers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. High Speed Oblivious Random Access Memory (HS-ORAM)

    Science.gov (United States)

    2015-09-01

    and Automated Teller Machines ( ATM ) security while generally impractical due to performance limitations and high acquisition costs. This idea has...HIGH SPEED OBLIVIOUS RANDOM ACCESS MEMORY (HS-ORAM) PRIVATE MACHINES , INC. SEPTEMBER 2015 FINAL TECHNICAL REPORT...UNIT NUMBER I1 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Private Machines Inc. 164 20th Street #3D Brooklyn, NY 11232 8. PERFORMING

  16. Overall optimization of high-speed semiconductor laser modules

    Institute of Scientific and Technical Information of China (English)

    LIU Yu; CHEN ShuoFu; WANG Xin; YUAN HaiQing; XIE Liang; ZHU NingHua

    2009-01-01

    Based on the high frequency techniques such as frequency response measurement, equivalent circuit modeling and packaging parasitics compensation, a comprehensive optimization method for packag-ing high-speed semiconductor laser module is presented in this paper. The experiments show that the small-signal magnitude frequency response of the TO packaged laser module is superior to that of laser diode in frequencies, and the in-band flatness and the phase-frequency linearity are also im-proved significantly.

  17. Ultra-high-speed serial optical communications: Enabling technologies

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Galili, Michael; Mulvad, Hans Christian Hansen

    2008-01-01

    This paper will present recently identified and demonstrated key technologies for ultra-high-speed serial communications. Certain key components such as stabilised highly non-linear fibre switches, periodically poled Lithium Niobate devices and semiconductor optical amplifiers will be described...... with demonstrations of 640 Gb/s transmission, clock recovery, demultiplexing, add/drop, wavelength conversion and channel identification. Timing jitter tolerance is addressed through techniques to create flat-top pulses....

  18. Galvanometer deflection: a precision high-speed system.

    Science.gov (United States)

    Jablonowski, D P; Raamot, J

    1976-06-01

    An X-Y galvanometer deflection system capable of high precision in a random access mode of operation is described. Beam positional information in digitized form is obtained by employing a Ronchi grating with a sophisticated optical detection scheme. This information is used in a control interface to locate the beam to the required precision. The system is characterized by high accuracy at maximum speed and is designed for operation in a variable environment, with particular attention placed on thermal insensitivity.

  19. Is Extremely High Life Satisfaction during Adolescence Advantageous?

    Science.gov (United States)

    Suldo, Shannon M.; Huebner, E. Scott

    2006-01-01

    This study examined whether extremely high life satisfaction was associated with adaptive functioning or maladaptive functioning. Six hundred ninety-eight secondary level students completed the Students' Life Satisfaction Scale [Huebner, 1991a, School Psychology International, 12, pp. 231-240], Youth Self-Report of the Child Behavior Checklist…

  20. common lower extremity injuries in female high school soccer ...

    African Journals Online (AJOL)

    studies on soccer concentrate on male soccer players.5-7 Although participation ... the prevalence and injury profile of lower extremity injuries in female high school ... An extended duration of skills (p=0.0001) and fitness (p=0.02) training in this .... The results (Table V) show that shin guards were associated with a reduced ...

  1. Phosphoglucose isomerase genotype affects running speed and heat shock protein expression after exposure to extreme temperatures in a montane willow beetle.

    Science.gov (United States)

    Rank, Nathan E; Bruce, Douglas A; McMillan, David M; Barclay, Colleen; Dahlhoff, Elizabeth P

    2007-03-01

    Eastern Sierra Nevada populations of the willow beetle Chrysomela aeneicollis commonly experience stressfully high and low environmental temperatures that may influence survival and reproduction. Allele frequencies at the enzyme locus phosphoglucose isomerase (PGI) vary across a climatic latitudinal gradient in these populations, with PGI allele 1 being most common in cooler regions and PGI allele 4 in warmer ones. PGI genotypes differ in heat and cold tolerance and in expression of a 70 kDa heat shock protein. Here we examine genetic, behavioral and environmental factors affecting a performance character, running speed, for willow beetles, and assess effects of consecutive cold and heat exposure on running speed and expression of Hsp70 in the laboratory. In nature, running speed depends on air temperature and is higher for males than females. Mating beetles ran faster than single beetles, and differences among PGI genotypes in male running speed depended on the presence of females. In the laboratory, exposure to cold reduced subsequent running speed, but the amount of this reduction depended on PGI genotype and previous thermal history. Effects of exposure to heat also depended on life history stage and PGI genotype. Adults possessing allele 1 ran fastest after a single exposure to stressful temperature, whereas those possessing allele 4 ran faster after repeated exposure. Larvae possessing allele 4 ran fastest after a single stressful exposure, but running speed generally declined after a second exposure to stressful temperature. The ranking of PGI genotypes after the second exposure depended on whether a larva had been exposed to cold or heat. Effects of temperature on Hsp70 expression also varied among PGI genotypes and depended on type of exposure, especially for adults (single heat exposure, two cold exposures: PGI 1-1>1-4>4-4; other multiple extreme exposures: 4-4>1-4>1-1). There was no consistent association between alleles at other polymorphic enzyme loci

  2. VERY HIGH-SPEED DRILL STRING COMMUNICATIONS NETWORK

    Energy Technology Data Exchange (ETDEWEB)

    David S. Pixton

    2002-11-01

    Testing of a high-speed digital data transmission system for drill pipe is described. Passive transmission of digital data through 1000 ft of telemetry drill pipe has been successfully achieved. Data rates of up to 2 Mbit/sec have been tested through the 1000 ft system with very low occurrence of data errors: required error correction effort is very low or nonexistent. Further design modifications have been made to improve manufacturability and high pressure robustness of the transmission line components. Failure mechanisms of previous designs at high pressure and high temperature are described. Present design limitations include high temperature application.

  3. Convective high-speed flow and field-aligned high-speed flows explored by TC-1

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; LIU ZhenXing; MA ZhiWei; W.BAUMJOHANN; M.W.DUNLOP4; WANG GuangJun; WANG Xiao; H.REME; C.CARR

    2008-01-01

    From June 1, 2004 to October 31, 2006, a total 465 high-speed flow events are observed by the TC-1 satellite in the near-Earth region (-13 RE < X < -9 RE, |Y|<10 RE, |2|<5 RE). Based on the angle between the flow and the magnetic field, the high-speed flow events are further divided into two types, that is,field-aligned high-speed flow (FAHF) in the plasma sheet boundary and convective bursty bulk flow (BBF) in the center plasma sheet. Among the total 465 high-speed flow events, there are 371 FAHFs,and 94 BBFs. The CHF are mainly concentrated in the plasma sheet, the intersection angle between the flow and the magnetic field is larger, the magnetic field intensity is relatively weak. The FHF are mainly distributed near the boundary layer of the plasma sheet, the intersection angle between the flow and magnetic field is smaller, and the magnetic field intensity is relatively strong. The convective BBFs have an important effect on the substorm.

  4. Extreme high-head portables provide more pumping options

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2006-10-15

    Three years ago, Godwin Pumps, one of the largest manufacturers of portable pumps, introduced its Extreme Duty High Lift (HL) series of pumps and more mines are finding unique applications for these pumps. The Extreme HL series is a range single-stage Dri-Prime pumps with heads up to 600 feet and flows up to 5,000 gallons per minute. The American Coal Co.'s Galatia mine, an underground longwall mine in southern Illinois, used an HL 160 to replace a multiple-staged centrifugal pump. It provided Galatia with 1,500 gpm at 465 ft. 3 photos.

  5. Methodology development and integrated control power-speed high-class handball players

    Directory of Open Access Journals (Sweden)

    Josan I.A.

    2014-05-01

    Full Text Available Purpose : based practices and identify effective means of controlling the level of development of power-speed high-class handball players. Material : The study involved 24 women's handball team player of Super League of Ukraine "Dneprjanka" Kherson. Results : methodical conditions defined development speed-strength. Revealed significant changes in terms of the development of power-speed after applying the proposed method of training. Hit run handball throws the ball with 7 meters at best point guards (4.9 ball and welterweight (4.6 ball players, and the lowest at the extremes (4.4 ball and linear (4.4 ball players. Analyzing the accuracy of the shots from a 9-meter mark, found no significant differences between the mean values are not established. Conclusions : Exercise speed-strength of character necessary to carry out the preparatory and in the early part of the basic training. Handball is recommended to use individual tasks to improve the general and special speed-strength training.

  6. Difference in muscle activation patterns during high-speed versus standard-speed yoga: A randomized sequence crossover study.

    Science.gov (United States)

    Potiaumpai, Melanie; Martins, Maria Carolina Massoni; Wong, Claudia; Desai, Trusha; Rodriguez, Roberto; Mooney, Kiersten; Signorile, Joseph F

    2017-02-01

    To compare the difference in muscle activation between high-speed yoga and standard-speed yoga and to compare muscle activation of the transitions between poses and the held phases of a yoga pose. Randomized sequence crossover trial SETTING: A laboratory of neuromuscular research and active aging Interventions: Eight minutes of continuous Sun Salutation B was performed, at a high speed versus a standard-speed, separately. Electromyography was used to quantify normalized muscle activation patterns of eight upper and lower body muscles (pectoralis major, medial deltoids, lateral head of the triceps, middle fibers of the trapezius, vastus medialis, medial gastrocnemius, thoracic extensor spinae, and external obliques) during the high-speed and standard-speed yoga protocols. Difference in normalized muscle activation between high-speed yoga and standard-speed yoga. Normalized muscle activity signals were significantly higher in all eight muscles during the transition phases of poses compared to the held phases (pyoga across the entire session. Our results show that transitions from one held phase of a pose to another produces higher normalized muscle activity than the held phases of the poses and that overall activity is greater during highspeed yoga than standard-speed yoga. Therefore, the transition speed and associated number of poses should be considered when targeting specific improvements in performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Development of a high speed crowbar for LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Friedrichs, C. Jr.; Lyles, J.T.M.; Doub, J.M.

    1997-08-01

    Each of the four 200 MHz Final Power Amplifiers (FPAs) in the LANSCE proton linac has its own capacitor bank and crowbar. The dissipation in the 10{Omega} crowbar limiting resistor is as high as 67 kW, and oil cooling is used. The authors stated upgrade goal was to substantially reduce the limiting resistor dissipation and eliminate the oil cooling. Early tests showed that the fault energy quickly rose to unacceptable levels as the current limiting resistance was reduced. FPA arcs are normally quenched by interrupting the FPA modulator current, and the crowbar waits 10 {mu}s for this to occur. The successful upgrade strategy was to replace the 10{Omega} resistor with a 3{Omega} air cooled resistor and to add a high speed crowbar circuit which operates only if there are simultaneous arcs in the FPA and its modulator. This paper describes the high speed circuit and its interface with the existing crowbar. Test results are also given.

  8. REDUCTION OF EMISSIONS FROM A HIGH SPEED FERRY

    Energy Technology Data Exchange (ETDEWEB)

    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

  9. Fine micro-welding of thin metal sheet by high speed laser scanning

    Science.gov (United States)

    Okamoto, Yasuhiro; Gillner, Arnold; Olowinsky, Alexander; Gedicke, Jens; Uno, Yoshiyuki

    2007-05-01

    Recently, since the size of component becomes smaller, then the welding of thin metal sheet has been required. Besides, the flexibility of process is important according to the accessibility especially for small components. Fraunhofer Institute for Laser Technology had developed the SHADOW ® welding technology, in which the high speed joining with small distortion is possible using pulsed Nd:YAG laser. The possibility of high speed and high quality welding had been reported by using single-mode fiber laser. The combination of micro beam and high speed laser scanning has the advantages for thin metal sheet welding. Therefore, the characteristics of micro-welding for thin metal sheet were investigated by high speed laser scanning, in which the welding was carried out by high speed scanner system with single-mode fiber laser and pulsed Nd:YAG laser. The proper welding region was narrow by the laser beam with a large focus diameter of 160 μm without pulse control, while a small focus diameter of 22 μm can control the welding state widely. A small focus diameter can perform the excellent welding seam from the extreme beginning without pulse control. The penetration depth can be controlled by the energy density with a small focus diameter of 22 μm at the energy densities less than 1 J/mm2. Besides, the unique periodic structure appeared at the high velocity of beam scanning with a small focus diameter. Moreover, the overlap welding of 25 μm thickness sheet can be performed regardless of small gap distance between two sheets by the laser beam with a small focus diameter of 22 μm.

  10. High-speed optical frequency-domain imaging

    OpenAIRE

    Yun, S. H.; Tearney, G. J.; Boer; Iftimia, N. V.; Bouma, B. E.

    2003-01-01

    We demonstrate high-speed, high-sensitivity, high-resolution optical imaging based on optical frequency-domain interferometry using a rapidly-tuned wavelength-swept laser. We derive and show experimentally that frequency-domain ranging provides a superior signal-to-noise ratio compared with conventional time-domain ranging as used in optical coherence tomography. A high sensitivity of −110 dB was obtained with a 6 mW source at an axial resolution of 13.5 µm and an A-line rate of 15.7 kHz, rep...

  11. ACUTE EFFECTS OF STATIC STRETCHING, DYNAMIC EXERCISES, AND HIGH VOLUME UPPER EXTREMITY PLYOMETRIC ACTIVITY ON TENNIS SERVE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Ertugrul Gelen

    2012-12-01

    Full Text Available The purpose of this study was to compare the acute effects of static stretching; dynamic exercises and high volume upper extremity plyometric activity on tennis serve performance. Twenty-six elite young tennis players (15.1 ± 4.2 years, 167.9 ± 5.8 cm and 61.6 ± 8.1 kg performed 4 different warm-up (WU routines in a random order on non-consecutive days. The WU methods consisted of traditional WU (jogging, rally and serve practice (TRAD; traditional WU and static stretching (TRSS; traditional WU and dynamic exercise (TRDE; and traditional WU and high volume upper extremity plyometric activity (TRPLYP. Following each WU session, subjects were tested on a tennis serve ball speed test. TRAD, TRSS, TRDE and TRPLYO were compared by repeated measurement analyses of variance and post-hoc comparisons. In this study a 1 to 3 percent increase in tennis serve ball speed was recorded in TRDE and TRPLYO when compared to TRAD (p 0.05. ICCs for ball speed showed strong reliability (0.82 to 0.93 for the ball speed measurements.The results of this study indicate that dynamic and high volume upper extremity plyometric WU activities are likely beneficial to serve speed of elite junior tennis players.

  12. High Speed Video Applications In The Pharmaceutical Industry

    Science.gov (United States)

    Stapley, David

    1985-02-01

    The pursuit of quality is essential in the development and production of drugs. The pursuit of excellence is relentless, a never ending search. In the pharmaceutical industry, we all know and apply wide-ranging techniques to assure quality production. We all know that in reality none of these techniques are perfect for all situations. We have all experienced, the damaged foil, blister or tube, the missing leaflet, the 'hard to read' batch code. We are all aware of the need to supplement the traditional techniques of fault finding. This paper shows how high speed video systems can be applied to fully automated filling and packaging operations as a tool to aid the company's drive for high quality and productivity. The range of products involved totals some 350 in approximately 3,000 pack variants, encompassing creams, ointments, lotions, capsules, tablets, parenteral and sterile antibiotics. Pharmaceutical production demands diligence at all stages, with optimum use of the techniques offered by the latest technology. Figure 1 shows typical stages of pharmaceutical production in which quality must be assured, and highlights those stages where the use of high speed video systems have proved of value to date. The use of high speed video systems begins with the very first use of machine and materials: commissioning and validation, (the term used for determining that a process is capable of consistently producing the requisite quality) and continues to support inprocess monitoring, throughout the life of the plant. The activity of validation in the packaging environment is particularly in need of a tool to see the nature of high speed faults, no matter how infrequently they occur, so that informed changes can be made precisely and rapidly. The prime use of this tool is to ensure that machines are less sensitive to minor variations in component characteristics.

  13. Improved pulse laser ranging algorithm based on high speed sampling

    Science.gov (United States)

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

    2016-10-01

    Narrow pulse laser ranging achieves long-range target detection using laser pulse with low divergent beams. Pulse laser ranging is widely used in military, industrial, civil, engineering and transportation field. In this paper, an improved narrow pulse laser ranging algorithm is studied based on the high speed sampling. Firstly, theoretical simulation models have been built and analyzed including the laser emission and pulse laser ranging algorithm. An improved pulse ranging algorithm is developed. This new algorithm combines the matched filter algorithm and the constant fraction discrimination (CFD) algorithm. After the algorithm simulation, a laser ranging hardware system is set up to implement the improved algorithm. The laser ranging hardware system includes a laser diode, a laser detector and a high sample rate data logging circuit. Subsequently, using Verilog HDL language, the improved algorithm is implemented in the FPGA chip based on fusion of the matched filter algorithm and the CFD algorithm. Finally, the laser ranging experiment is carried out to test the improved algorithm ranging performance comparing to the matched filter algorithm and the CFD algorithm using the laser ranging hardware system. The test analysis result demonstrates that the laser ranging hardware system realized the high speed processing and high speed sampling data transmission. The algorithm analysis result presents that the improved algorithm achieves 0.3m distance ranging precision. The improved algorithm analysis result meets the expected effect, which is consistent with the theoretical simulation.

  14. Micro Mirrors for High-speed Laser Deflection and Patterning

    Science.gov (United States)

    Schenk, Harald; Grahmann, Jan; Sandner, Thilo; Wagner, Michael; Dauderstädt, Ulrike; Schmidt, Jan-Uwe

    This paper focuses on high-speed optical MEMS Scanners and Micro Mirror Arrays. Devices supporting spot/pixel rateshigher than 10 Mpixel/s are considered and discussed regarding limits and possibilities to further improve speed and optical properties. Several variants of both types, developed by our group, are presented. Scanning Micro Mirrors with frequencies up to 100 kHz enable spot rates of up to 130 Mpixels / s at 650 nm. Bragg-coatings enable high power applications up to 20 W (beam ø2 mm). Challenges like static and dynamic mirror planariy are discussed. A 29-kHz-scanner for laser projection serves as application example. Highly parallel operated Micro Mirror Arrays extend pattern speed to 10 Gpixel / s including analog grey scaling. Irradiation tests prove stable operation of the mirrors at DUV. Prospects regarding optical planarity and high reflective coatings are discussed. By means of two examples, laser patterning of semiconductor masks and laser patterning of Printed Circuit Boards, properties of the spatial light modulators are presented. The two device classes are compared regarding spot/pixel rate and frequency. The comparison includes representative MEMS device examples from literature.

  15. Research of inverse mathematical model to high-speed trains

    Institute of Scientific and Technical Information of China (English)

    朱涛; 肖守讷; 马卫华; 阳光武

    2014-01-01

    Operation safety and stability of the train mainly depend on the interaction between the wheel and rail. Knowledge of wheel/rail contact force is important for vehicle control systems that aim to enhance vehicle stability and passenger safety. Since wheel/rail contact forces of high-speed train are very difficult to measure directly, a new estimation process for wheel/rail contact forces was introduced in this work. Based on the state space equation, dynamic programming methods and the Bellman principle of optimality, the main theoretical derivation of the inversion mathematical model was given. The new method overcomes the weakness of large fluctuations which exist in current inverse techniques. High-speed vehicle was chosen as the research object, accelerations of axle box as input conditions, 10 degrees of freedom vertical vibration model and 17 degrees of freedom lateral vibration model were established, respectively. Under 250 km/h, the vertical and lateral wheel/rail forces were identified. From the time domain and frequency domain, the comparison of the results between inverse and SIMPACK models were given. The results show that the inverse mathematical model has high precision for inversing the wheel/rail contact forces of an operation high-speed vehicle.

  16. Thermal analysis of high speed permanent magnetic generator

    Institute of Scientific and Technical Information of China (English)

    LI WeiLi; ZHANG XiaoChen; CHENG ShuKang; CAO JunCi; ZHANG YiHuang

    2012-01-01

    High-speed permanent magnetic generators (HSPMG) are common and important power generation equipments used in distributed generation systems.A 100 kW level HSPMG is investigated in this paper,and it is fluid-thermal coupling analyzed.The transient 2D electromagnetic field while machine is under rated operating is analyzed by using the time-stepping FEM,from which the electromagnetic performances and the loss distributions are obtained.Then,an analysis model for fluid-solid temperature field analysis is established.Taking losses as the distributed heat sources,the 3D thermal field is coupling calculated.The variations of heat transfer coefficient and temperature of fluid in stator grooves along the axial direction,as well as the whole region 3D temperature distribution in HSPMG are obtained.Then,considering the variations of heat sources distributions and heat transfer conditions,3D temperature fields of HSPMG operating under different speeds are calculated,and the influences of machine operating speed on the HSPMG thermal performance are studied,based on which,the functions of machine temperature with operating speed and stator windings resistance are proposed.The obtained conclusions may provide a useful reference for the design and research of HSPMG.

  17. High speed multiplier using Nikhilam Sutra algorithm of Vedic mathematics

    Science.gov (United States)

    Pradhan, Manoranjan; Panda, Rutuparna

    2014-03-01

    This article presents the design of a new high-speed multiplier architecture using Nikhilam Sutra of Vedic mathematics. The proposed multiplier architecture finds out the compliment of the large operand from its nearest base to perform the multiplication. The multiplication of two large operands is reduced to the multiplication of their compliments and addition. It is more efficient when the magnitudes of both operands are more than half of their maximum values. The carry save adder in the multiplier architecture increases the speed of addition of partial products. The multiplier circuit is synthesised and simulated using Xilinx ISE 10.1 software and implemented on Spartan 2 FPGA device XC2S30-5pq208. The output parameters such as propagation delay and device utilisation are calculated from synthesis results. The performance evaluation results in terms of speed and device utilisation are compared with earlier multiplier architecture. The proposed design has speed improvements compared to multiplier architecture presented in the literature.

  18. High resolution modelling of extreme precipitation events in urban areas

    Science.gov (United States)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

  19. Characterizing pyrotechnic igniter output with high-speed schlieren imaging

    Science.gov (United States)

    Skaggs, M. N.; Hargather, M. J.; Cooper, M. A.

    2017-01-01

    Small-scale pyrotechnic igniter output has been characterized using a high-speed schlieren imaging system for observing critical features of the post-combustion flow. The diagnostic, with laser illumination, was successfully applied towards the quantitative characterization of the output from Ti/KClO_4 and TiH_{1.65}/KClO_4 pyrotechnic igniters. The high-speed image sequences showed shock motion, burned gas expansion, and particle motion. A statistical-based analysis methodology for tracking the full-field shock motion enabled straightforward comparisons across the experimental parameters of pyrotechnic material and initial density. This characterization of the mechanical energy of the shock front within the post-combustion environment is a necessary addition to the large body of literature focused on pyrotechnic combustion behavior within the powder bed. Ultimately, understanding the role that the combustion behavior has on the resulting multiphase environment is required for tailored igniter development and comparative performance assessments.

  20. Numerical Simulation for Ventilated Supercavitation High Speed Underwater Vehicle

    Institute of Scientific and Technical Information of China (English)

    YANG Wu-gang; YANG Zhen-cai; CHU Yan; DENG Qiu-xia; LI Ya-rong; ZHANG Yu-wen

    2009-01-01

    Supercavitation is a revolutionary technique to achieve high drag reduction for underwater vehicle. It can help us to break through the conventional speed barrier. This article presents a numerical algorithm for ventilated supercavitation flow field based on mixture multiphase flow model, briefs the calculation results and compares them with that tested in high-speed water tunnel and towing tank. The mathematical model, its numerical calculation method, computational region and boundary conditions are discussed in detail. Some pertinent nondimensional parameters about the ventilated supercavitation, such as geometrical configuration of supercavity, drag coefficient and ventilation rate are investigated. Reynolds number is selected to predict gas ventilation rate instead of Froude number. Finally, based on the test and simulation results, a semi-empirical formula of the ventilation rate estimation suitable for different conical angle caritators is proposed.

  1. High Speed Photography What Role Does It Play In Mining?

    Science.gov (United States)

    Crosby, William A.

    1987-09-01

    High speed photography is being employed to help improve the efficiency of a number of different mining activities. Its principal use, however, is as an aid in the optimization of blasting operations. Blasts are commonly of very short duration and great benefit can thus be gained by being able to observe the events at a suitably selected slow motion over an extended period of time. This paper presents an overview of some of the high speed photographic applications in both surface and underground operations using qualitative and quantitative techniques. The primary use is the direct photography of the blast, the analysis of the resulting films representing the bulk of the optimization work. Other applications are designed to check out individual blast components, particularly evaluating blast tamping, and actual delay element times for such accessories as detonating relays, down-the-hole delays and other delaying and initiating systems.

  2. Photonic Technologies for Ultra-High-Speed Information Highways

    DEFF Research Database (Denmark)

    Bouchoule, S; Lèfevre, R.; Legros, E.;

    1999-01-01

    The ACTS project HIGHWAY (AC067) addresses promising ultra-high speed optoelectronic components and system technologies for 40 Gbit/s time-division-multiplexed (TDM) transport systems. Advanced 40 Gbit/s TDM system lab demonstrators are to be realized and tested over installed field fiber testbed....... This paper reviews the current status of 40 Gbit/s TDM components and subsystem technologies achieved in HIGHWAY. The results of HIGHWAY 40 Gbit/s TDM systems and field tests will be reported in a subsequent paper. (C) 1999 Academic Press.......The ACTS project HIGHWAY (AC067) addresses promising ultra-high speed optoelectronic components and system technologies for 40 Gbit/s time-division-multiplexed (TDM) transport systems. Advanced 40 Gbit/s TDM system lab demonstrators are to be realized and tested over installed field fiber testbeds...

  3. Soliton-based ultra-high speed optical communications

    Indian Academy of Sciences (India)

    Akira Hasegawa

    2001-11-01

    Multi-terabit/s, ultra-high speed optical transmissions over several thousands kilometers on fibers are becoming a reality. Most use RZ (Return to Zero) format in dispersion-managed fibers. This format is the only stable waveform in the presence of fiber Kerr nonlinearity and dispersion in all optical transmission lines with loss compensated by periodic amplifications. The nonlinear Schrödinger equation assisted by the split step numerical solutions is commonly used as the master equation to describe the information transfer in optical fibers. All these facts are the outcome of research on optical solitons in fibers in spite of the fact that the commonly used RZ format is not always called a soliton format. The overview presented here attempts to incorporate the role of soliton-based communications research in present day ultra-high speed communications.

  4. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    Directory of Open Access Journals (Sweden)

    Shih-Chen Shi

    2016-07-01

    Full Text Available The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC, hydroxypropyl methylcellulose phthalate (HPMCP, and hydroxypropyl methylcellulose acetate succinate (HPMCAS film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives.

  5. High Speed Reconfigurable FFT Design by Vedic Mathematics

    CERN Document Server

    Raman, Ashish; Sarin, R K

    2010-01-01

    The Fast Fourier Transform (FFT) is a computationally intensive digital signal processing (DSP) function widely used in applications such as imaging, software-defined radio, wireless communication, instrumentation. In this paper, a reconfigurable FFT design using Vedic multiplier with high speed and small area is presented. Urdhava Triyakbhyam algorithm of ancient Indian Vedic Mathematics is utilized to improve its efficiency. In the proposed architecture, the 4x4 bit multiplication operation is fragmented reconfigurable FFT modules. The 4x4 multiplication modules are implemented using small 2x2bit multipliers. Reconfigurability at run time is provided for attaining power saving. The reconfigurable FFT has been designed, optimized and implemented on an FPGA based system. This reconfigurable FFT is having the high speed and small area as compared to the conventional FFT.

  6. High-speed Integrated Circuits for electrical/Optical Interfaces

    DEFF Research Database (Denmark)

    Jespersen, Christoffer Felix

    2008-01-01

    This thesis is a continuation of the effort to increase the bandwidth of communicationnetworks. The thesis presents the results of the design of several high-speed electrical ircuits for an electrical/optical interface. These circuits have been a contribution to the ESTA project in collaboration ...... as examples. Finally, it is concluded that the VIP-2 process is suitable technology for creating circuits for 100 Gb/s communication networks. Keywords: Indium Phosphide (InP), DHBT, VCO, Colpitt, Static Divider, CDR, PLL, Transceiver...... represents the avant-garde of InP technology, with ft and fmax well above 300 GHz. Principles of high speed design are presented and described as a useful background before proceeding to circuits. A static divider is used as an example to illustrate many of the design principles. Theory and fundamentals...

  7. High speed single charge coupled device Cranz-Schardin camera

    Science.gov (United States)

    Deblock, Y.; Ducloux, O.; Derbesse, L.; Merlen, A.; Pernod, P.

    2007-03-01

    This article describes an ultrahigh speed visualization system based on a miniaturization of the Cranz-Schardin principle. It uses a set of high power light emitting diodes (LEDs) (Golden Dragon) as the light source and a highly sensitive charge coupled device (CCD) camera for reception. Each LED is fired in sequence and images the refraction index variation between two relay lenses, on a partial region of a CCD image sensor. The originality of this system consists in achieving several images on a single CCD during a frame time. The number of images is 4. The time interval between successive firings determines the speed of the imaging system. This time lies from 100nsto10μs. The light pulse duration lies from 100nsto10μs. The principle and the optical and electronic parts of such a system are described. As an example, some images of acoustic waves propagating in water are presented.

  8. High-speed measurement of firearm primer blast waves

    CERN Document Server

    Courtney, Michael; Eng, Jonathan; Courtney, Amy

    2012-01-01

    This article describes a method and results for direct high-speed measurements of firearm primer blast waves employing a high-speed pressure transducer located at the muzzle to record the blast pressure wave produced by primer ignition. Key findings are: 1) Most of the lead styphnate based primer models tested show 5.2-11.3% standard deviation in the magnitudes of their peak pressure. 2) In contrast, lead-free diazodinitrophenol (DDNP) based primers had standard deviations of the peak blast pressure of 8.2-25.0%. 3) Combined with smaller blast waves, these large variations in peak blast pressure of DDNP-based primers led to delayed ignition and failure to fire in brief field tests.

  9. High-Speed Coherent Raman Fingerprint Imaging of Biological Tissues

    CERN Document Server

    Camp, Charles H; Heddleston, John M; Hartshorn, Christopher M; Walker, Angela R Hight; Rich, Jeremy N; Lathia, Justin D; Cicerone, Marcus T

    2014-01-01

    We have developed a coherent Raman imaging platform using broadband coherent anti-Stokes Raman scattering (BCARS) that provides an unprecedented combination of speed, sensitivity, and spectral breadth. The system utilizes a unique configuration of laser sources that probes the Raman spectrum over 3,000 cm$^{-1}$ and generates an especially strong response in the typically weak Raman "fingerprint" region through heterodyne amplification of the anti-Stokes photons with a large nonresonant background (NRB) while maintaining high spectral resolution of $<$ 13 cm$^{-1}$. For histology and pathology, this system shows promise in highlighting major tissue components in a non-destructive, label-free manner. We demonstrate high-speed chemical imaging in two- and three-dimensional views of healthy murine liver and pancreas tissues and interfaces between xenograft brain tumors and the surrounding healthy brain matter.

  10. High-speed measurement of rifle primer blast waves

    CERN Document Server

    Courtney, Michael

    2011-01-01

    This article describes a method and results for direct high-speed measurements of rifle primer blast waves employing a high-speed pressure transducer located at the muzzle to record the blast pressure wave produced by primer ignition. Our key findings are: 1) Most of the primer models tested show 5-12% standard deviation in the magnitudes of their peak pressure. 2) For most primer types tested, peak pressure magnitudes are well correlated with measured primer masses so that significant reductions in standard deviation are expected to result from sorting primers by mass. 3) A range of peak pressures from below 200 psi to above 500 psi is available in different primer types.

  11. Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

    Directory of Open Access Journals (Sweden)

    Jamaliah Idris

    2013-01-01

    Full Text Available Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis parameters, such as cathodic current density and temperature at constant pH, on electrodeposition and microstructure of Ni-Co alloys were examined. A homogeneous surface morphology was obtained at all current densities of the plated samples, and it was evident that the current density and temperature affect the coating thickness of Ni-Co alloy coatings.

  12. High-speed imaging polarimetry using liquid crystal modulators

    Directory of Open Access Journals (Sweden)

    Ambs P.

    2010-06-01

    Full Text Available This paper deals with dynamic polarimetric imaging techniques. The basics of modern polarimetry have been known for one and a half century, but no practical high-speed implementation providing the full polarization information is currently available. Various methods are reviewed which prove to be a trade-off between the complexity of the optical set-up and the amount of polarimetric information they provide (ie the number of components of the Stokes vector. Techniques using liquid crystal devices, incepted in the late 1990's, are emphasized. Optical set-ups we implemented are presented. We particularly focus on high-speed techniques (i.e. faster than 200 Hz using ferroelectric liquid crystal devices.

  13. Extremely high Q -factor metamaterials due to anapole excitation

    Science.gov (United States)

    Basharin, Alexey A.; Chuguevsky, Vitaly; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N.

    2017-01-01

    We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit unusual, almost perfect anapole behavior in the sense that the electric dipole radiation is almost canceled by the toroidal dipole one, producing thus an extremely high Q -factor at the resonance frequency. Thus we have demonstrated theoretically and experimentally that metamaterials approaching ideal anapole behavior have very high Q -factor. The size of the system, at the millimeter range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q -factor. In spite of the very low radiation losses the estimated local fields at the metamolecules are extremely high, of the order of 104 higher than the external incoming field.

  14. High speed preprocessing in real time telemetry systems

    Science.gov (United States)

    Strock, O. J.; O'Brien, Michael

    A versatile high-speed preprocessor, the EMR 8715, is described which is used as a closed-coupled input device for the host computer in a telemetry system. Much of the data and time merging, number conversion, floating-point processing, and data distribution are performed by the system, reducing the host load. The EMR 8715 allows a choice of serial processing, parallel processing, or a combination of the two, on a measurement-by-measurement basis.

  15. High Speed Friction Microscopy and Nanoscale Friction Coefficient Mapping

    OpenAIRE

    Bosse, James L.; Lee, Sungjun; Huey, Bryan D; Andersen, Andreas Sø; Sutherland, Duncan S

    2014-01-01

    As mechanical devices in the nano/micro length scale are increasingly employed, it is crucial to understand nanoscale friction and wear especially at technically relevant sliding velocities. Accordingly, a novel technique has been developed for Friction Coefficient Mapping (FCM), leveraging recent advances in high speed AFM. The technique efficiently acquires friction versus force curves based on a sequence of images at a single location, each with incrementally lower loads. As a result, true...

  16. A new approach of high speed cutting modelling: SPH method

    OpenAIRE

    LIMIDO, Jérôme; Espinosa, Christine; Salaün, Michel; Lacome, Jean-Luc

    2006-01-01

    The purpose of this study is to introduce a new approach of high speed cutting numerical modelling. A lagrangian Smoothed Particle Hydrodynamics (SPH) based model is carried out using the Ls-Dyna software. SPH is a meshless method, thus large material distortions that occur in the cutting problem are easily managed and SPH contact control permits a “natural” workpiece/chip separation. Estimated chip morphology and cutting forces are compared to machining dedicated code results and experimenta...

  17. SPH method applied to high speed cutting modelling

    OpenAIRE

    LIMIDO, Jérôme; Espinosa, Christine; Salaün, Michel; Lacome, Jean-Luc

    2007-01-01

    The purpose of this study is to introduce a new approach of high speed cutting numerical modelling. A Lagrangian smoothed particle hydrodynamics (SPH)- based model is arried out using the Ls-Dyna software. SPH is a meshless method, thus large material distortions that occur in the cutting problem are easily managed and SPH contact control permits a "natural" workpiece/chip separation. The developed approach is compared to machining dedicated code results and experimental data. The SPH cutting...

  18. NASA/GE Collaboration on Open Rotors - High Speed Testing

    Science.gov (United States)

    VanZante, Dale E.

    2011-01-01

    A low-noise open rotor system is being tested in collaboration with General Electric and CFM International, a 50/50 joint company between Snecmaand GE. Candidate technologies for lower noise will be investigated as well as installation effects such as pylon integration. Current test status for the 8x6 SWT high speed testing is presented as well as future scheduled testing which includes the FAA/CLEEN test entry. The tunnel blockage and propeller thrust calibration configurations are shown.

  19. Instrumentation for propulsion systems development. [high speed fans and turbines

    Science.gov (United States)

    Warshawsky, I.

    1978-01-01

    Apparatus and techniques developed or used by NASA-Lewis to make steady state or dynamic measurements of gas temperature, pressure, and velocity and of the temperature, tip clearance, and vibration of the blades of high-speed fans or turbines are described. The advantages and limitations of each instrument and technique are discussed and the possibility of modifying them for use in developing various propulsion systems is suggested.

  20. Beijing-Tianjin Intercity High-speed Line

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Ever since 2003, under the guidance of the scientific development concept and in line with the decisions and deployments made by the Party Central Committee and the State Council, China Railways has eagerly taken the golden opportunity for development, to facilitate the implementation of the Mid-term and Long-term Railway Network Development Program, and so it has achieved bumper significant accomplishments in the modernization progress, with Beijing-Tianjin Intercity High-speed Line as one of the exemplary representatives.

  1. Study on Electromagnetic Interference of high-speed railway EMU

    OpenAIRE

    Cheng, Qiang; Liu, Jin-Jiang; Cheng, Ning

    2013-01-01

    Electromagnetic radiation generated by pantograph-catenaries detachment is one of the inevitable problems with the development of high-speed railway this paper is focusing on the generating mechanism and characteristics of electromagnetic noise caused by pantograph-catenaries system. Based on previous research, we build an integrated model of catenaries and locomotive system, and study the electromagnetic disturbance characteristics using software FEKO. The simulation experiment results in th...

  2. Gearbox Reliability Collaborative High-Speed Shaft Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Keller, J.; McNiff, B.

    2014-09-01

    Instrumentation has been added to the high-speed shaft, pinion, and tapered roller bearing pair of the Gearbox Reliability Collaborative gearbox to measure loads and temperatures. The new shaft bending moment and torque instrumentation was calibrated and the purpose of this document is to describe this calibration process and results, such that the raw shaft bending and torque signals can be converted to the proper engineering units and coordinate system reference for comparison to design loads and simulation model predictions.

  3. High Speed Area Efficient 8-point FFT using Vedic Multiplier

    Directory of Open Access Journals (Sweden)

    Avneesh Kumar Mishra

    2014-12-01

    Full Text Available A high speed fast fourier transform (FFT design by using three algorithm is presented in this paper. In algorithm 3, 4-bit Vedic multiplier based technique are used in FFT. In this technique used in three 4-bit ripple carry adder and four 2*2 Vedic multiplier. The main parameter of this paper is number of slice, 4-input LUTS and maximum combinational path delay were calculate.

  4. Determination of aminocresol isomers by high-speed liquid chromatography.

    Science.gov (United States)

    Sakurai, H; Kito, M

    Aminocresol isomers (4-hydroxy-m-toluidine [II], 3-hydroxy-p-toluidine [II], 2-hydroxy-p-toluidine [III]) and p-aminophenol have been separated and determined by a high-speed liquid Chromatographie method. Since this method is applicable in aqueous media, it was used to investigate the suitability of a haemin-cysteine system as a model for the cytochrome P-450 mono-oxygenase system, by determination of the [I], [II], [III] and p-aminophenol formed.

  5. Wetting dynamics at high values of contact line speed

    OpenAIRE

    Пономарев, К. О.; Феоктистов, Дмитрий Владимирович; Орлова, Евгения Георгиевна

    2015-01-01

    Experimental results analyses of dynamic contact angle change under the conditions of substrate wetting by distilled water at high values of the contact line speed was conducted. Three spreading modes for copper substrates with different roughness were selected: drop formation, spreading and equilibrium contact angle formation. Peculiarity of droplet spreading on superhydrophobic surface is found. It consists in a monotonic increase of the advancing dynamic contact angle. The effect of the dr...

  6. High Speed White Dwarf Asteroseismology with the Herty Hall Cluster

    Science.gov (United States)

    Gray, Aaron; Kim, A.

    2012-01-01

    Asteroseismology is the process of using observed oscillations of stars to infer their interior structure. In high speed asteroseismology, we complete that by quickly computing hundreds of thousands of models to match the observed period spectra. Each model on a single processor takes five to ten seconds to run. Therefore, we use a cluster of sixteen Dell Workstations with dual-core processors. The computers use the Ubuntu operating system and Apache Hadoop software to manage workloads.

  7. Florida Turbine Technology (FTT). High Speed Machining of IN100

    Science.gov (United States)

    2006-06-01

    which burnish the surface and develop the fine finish for which deep hole gun drilling is known. Gun drilling was developed for use in drilling of...current process in place to manufacture the rotor shaft. The NCDMM will evaluate methods of manufacturing a .250” diameter hole , 4.0 inches deep in the...forged IN100 material. The hole will need to maintain a geometric tolerance of .002” true position. The NCDMM will also evaluate methods for High Speed

  8. Engineering models of high speed penetration into geological shields

    Science.gov (United States)

    Ben-Dor, Gabi; Dubinsky, Anatoly; Elperin, Tov

    2014-03-01

    The survey is dedicated to approximate empirical and analytical models which were suggested for describing high-speed penetration into geological shields. This review differs from the previously published reviews on this topic in the following respects: (i) includes a large number of models; (ii) describes models suggested during recent years; (iii) much attention is given to models which have been originally published in Russian and are not well known in the West. References list includes 81 items.

  9. Analysis of OFDM Applied to Powerline High Speed Digital Communication

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Jian; YANG Gong-xu

    2003-01-01

    The low voltage powerline is becoming a powerful solution to home network, building automation, and internet access as a result of its wide distribution, easy access and little maintenance. The character of powerline channel is very complicated because it is an open net. This article analysed the character of the powerline channel,introduced the basics of OFDM(Orthogonal Frequency Division Multiplexing), and studied the OFDM applied into powerline high speed digital communication.

  10. Picosecond Semiconductor Lasers For Characterizing High-Speed Image Shutters

    Science.gov (United States)

    Pagano, T. S.; Janson, F. J.; Yates, G. J.; Jaramillo, S. A.

    1986-01-01

    A portable system that utilizes solid state electronic timing circuits and a pulsed semiconductor laser for characterizing the optical gate sequence of high-speed image shutters, including microchannel-plate intensifier tubes (MCPTs), and silicon-intensified target vidicons (SITVs), is described and compared to earlier methods of characterization. Gate sequences obtained using the system and streak camera data of the semiconductor laser pulse are presented, with a brief discussion of the electronic delay timing and avalanche circuits used in the system.

  11. Route toward high-speed nano-magnonics provided by pure spin currents

    Science.gov (United States)

    Divinskiy, B.; Demidov, V. E.; Demokritov, S. O.; Rinkevich, A. B.; Urazhdin, S.

    2016-12-01

    We study experimentally the possibility to utilize pulses of pure spin current, produced via the nonlocal spin injection mechanism, to generate short packets of spin waves propagating in nanoscale magnetic waveguides. Spatially and time-resolved micro-focus Brillouin light scattering spectroscopy measurements demonstrate that the excitation by spin current results in extremely fast transient response, enabling efficient generation of short spin-wave packets with duration down to a few nanoseconds. The proposed method opens a route for the implementation of high-speed magnonic systems for transmission and processing of information on the nanoscale.

  12. Shape optimization of high-speed penetrators: a review

    Science.gov (United States)

    Ben-Dor, Gabi; Dubinsky, Anatoly; Elperin, Tov

    2012-12-01

    In spite of a large number of publications on shape optimization of penetrating projectiles there are no dedicated surveys of these studies. The goal of the present review is to close this gap. The review includes more than 50 studies published since 1980 and devoted to solving particular problems of shape optimization of high-speed penetrators. We analyze publications which employed analytical and numerical method for shape optimization of high-speed penetrators against concrete, metal, fiber-reinforced plastic laminate and soil shields. We present classification of the mathematical models used for describing interaction between a penetrator and a shield. The reviewed studies are summarized in the table where we display the following information: the model; indicate whether the model accounts for or neglects friction at the surface of penetrator; criterion for optimization (depth of penetration into a semi-infinite shield, ballistic limit velocity for a shield having a finite thickness, several criteria); class of considered shapes of penetrators (bodies of revolution, different classes of 3-D bodies, etc.); method of solution (analytical or numerical); in comments we present additional information on formulation of the optimization problem. The survey also includes discussion on certain methodological facets in formulating shape optimization problems for high-speed penetrators.

  13. Numerical Simulation of a Planing Vessel at High Speed

    Institute of Scientific and Technical Information of China (English)

    Yumin Su; Qingtong Chen; Hailong Shen; Wei Lu

    2012-01-01

    Planing vessels are applied widely in civil and military situations.Due to their high speed,the motion of planning vessels is complex.In order to predict the motion of planning vessels,it is important to analyze the hydrodynamic performance of planning vessels at high speeds.The computational fluid dynamic method (CFD) has been proposed to calculate hydrodynamic performance of planning vessels.However,in most traditional CFD approaches,model tests or empirical formulas are needed to obtain the running attitude of the planing vessels before calculation.This paper presents a new CFD method to calculate hydrodynamic forces of planing vessels.The numerical method was based on Reynolds-Averaged Navier-Stokes (RANS)equations.The volume of fluid (VOF) method and the six-degrees-of-freedom equation were applied.An effective process was introduced to solve the numerical divergence problem in numerical simulation.Compared with experimental results,numerical simulation results indicate that both the running attitude and hydrodynamic performance can be predicted well at high speeds.

  14. Double Helical Gear Performance Results in High Speed Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2010-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  15. High speed turboprop aeroacoustic study (counterrotation). Volume 1: Model development

    Science.gov (United States)

    Whitfield, C. E.; Mani, R.; Gliebe, P. R.

    1990-01-01

    The isolated counterrotating high speed turboprop noise prediction program was compared with model data taken in the GE Aircraft Engines Cell 41 anechoic facility, the Boeing Transonic Wind Tunnel, and in NASA-Lewis' 8x6 and 9x15 wind tunnels. The predictions show good agreement with measured data under both low and high speed simulated flight conditions. The installation effect model developed for single rotation, high speed turboprops was extended to include counterotation. The additional effect of mounting a pylon upstream of the forward rotor was included in the flow field modeling. A nontraditional mechanism concerning the acoustic radiation from a propeller at angle of attach was investigated. Predictions made using this approach show results that are in much closer agreement with measurement over a range of operating conditions than those obtained via traditional fluctuating force methods. The isolated rotors and installation effects models were combines into a single prediction program, results of which were compared with data taken during the flight test of the B727/UDF engine demonstrator aircraft. Satisfactory comparisons between prediction and measured data for the demonstrator airplane, together with the identification of a nontraditional radiation mechanism for propellers at angle of attack are achieved.

  16. On the reversed Brayton cycle with high speed machinery

    Energy Technology Data Exchange (ETDEWEB)

    Backman, J.

    1996-12-31

    This work was carried out in the laboratory of Fluid Dynamics, at Lappeenranta University of Technology during the years 1991-1996. The research was a part of larger high speed technology development research. First, there was the idea of making high speed machinery applications with the Brayton cycle. There was a clear need to deepen the knowledge of the cycle itself and to make a new approach in the field of the research. Also, the removal of water from the humid air seemed very interesting. The goal of this work was to study methods of designing high speed machinery for the reversed Brayton cycle, from theoretical principles to practical applications. The reversed Brayton cycle can be employed as an air dryer, a heat pump or a refrigerating machine. In this research the use of humid air as a working fluid has an environmental advantage, as well. A new calculation method for the Brayton cycle is developed. In this method especially the expansion process in the turbine is important because of the condensation of the water vapour in the humid air. This physical phenomena can have significant effects on the level of performance of the application. Also, the influence of calculating the process with actual, achievable process equipment efficiencies is essential for the development of future machinery. The above theoretical calculations are confirmed with two different laboratory prototypes. (53 refs.)

  17. A high-speed interconnect network using ternary logic

    DEFF Research Database (Denmark)

    Madsen, Jens Kargaard; Long, S. I.

    1995-01-01

    This paper describes the design and implementation of a high-speed interconnect network (ICN) for a multiprocessor system using ternary logic. By using ternary logic and a fast point-to-point communication technique called STARI (Self-Timed At Receiver's Input), the communication between the proc......This paper describes the design and implementation of a high-speed interconnect network (ICN) for a multiprocessor system using ternary logic. By using ternary logic and a fast point-to-point communication technique called STARI (Self-Timed At Receiver's Input), the communication between...... the processors is free of clock skew and insensitive to any delay differences in buffers and wires. In addition, the number of signal wires and pins are reduced by 50 percent in comparison with a similar binary implementation. The ICN architecture is based on a crossbar topology and the high-speed part consists...... of two LSI GaAs chips, Interface and Crossbar, which were implemented in a 0.8 μm MESFET process. In a 4×4 ICN, communication at 300 Mbit/s per wire was demonstrated, which is twice as fast as pure synchronous and four times faster than pure asynchronous communication in the specific test set-up...

  18. High-speed imaging of blood splatter patterns

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, T.E.; Albright, K.A.; King, N.S.P.; Yates, G.J. (Los Alamos National Lab., NM (United States)); Levine, G.F. (California Dept. of Justice, Sacramento, CA (United States). Bureau of Forensic Services)

    1993-01-01

    The interpretation of blood splatter patterns is an important element in reconstructing the events and circumstances of an accident or crime scene. Unfortunately, the interpretation of patterns and stains formed by blood droplets is not necessarily intuitive and study and analysis are required to arrive at a correct conclusion. A very useful tool in the study of blood splatter patterns is high-speed photography. Scientists at the Los Alamos National Laboratory, Department of Energy (DOE), and Bureau of Forensic Services, State of California, have assembled a high-speed imaging system designed to image blood splatter patterns. The camera employs technology developed by Los Alamos for the underground nuclear testing program and has also been used in a military mine detection program. The camera uses a solid-state CCD sensor operating at approximately 650 frames per second (75 MPixels per second) with a microchannel plate image intensifier that can provide shuttering as short as 5 ns. The images are captured with a laboratory high-speed digitizer and transferred to an IBM compatible PC for display and hard copy output for analysis. The imaging system is described in this paper.

  19. High-speed imaging of blood splatter patterns

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, T.E.; Albright, K.A.; King, N.S.P.; Yates, G.J. [Los Alamos National Lab., NM (United States); Levine, G.F. [California Dept. of Justice, Sacramento, CA (United States). Bureau of Forensic Services

    1993-05-01

    The interpretation of blood splatter patterns is an important element in reconstructing the events and circumstances of an accident or crime scene. Unfortunately, the interpretation of patterns and stains formed by blood droplets is not necessarily intuitive and study and analysis are required to arrive at a correct conclusion. A very useful tool in the study of blood splatter patterns is high-speed photography. Scientists at the Los Alamos National Laboratory, Department of Energy (DOE), and Bureau of Forensic Services, State of California, have assembled a high-speed imaging system designed to image blood splatter patterns. The camera employs technology developed by Los Alamos for the underground nuclear testing program and has also been used in a military mine detection program. The camera uses a solid-state CCD sensor operating at approximately 650 frames per second (75 MPixels per second) with a microchannel plate image intensifier that can provide shuttering as short as 5 ns. The images are captured with a laboratory high-speed digitizer and transferred to an IBM compatible PC for display and hard copy output for analysis. The imaging system is described in this paper.

  20. High-speed imaging of blood splatter patterns

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, T.E.; Albright, K.A.; King, N.S.P.; Yates, G.J. [Los Alamos National Lab., NM (United States); Levine, G.F. [California Dept. of Justice, Sacramento, CA (United States). Bureau of Forensic Services

    1993-05-01

    The interpretation of blood splatter patterns is an important element in reconstructing the events and circumstances of an accident or crime scene. Unfortunately, the interpretation of patterns and stains formed by blood droplets is not necessarily intuitive and study and analysis are required to arrive at a correct conclusion. A very useful tool in the study of blood splatter patterns is high-speed photography. Scientists at the Los Alamos National Laboratory, Department of Energy (DOE), and Bureau of Forensic Services, State of California, have assembled a high-speed imaging system designed to image blood splatter patterns. The camera employs technology developed by Los Alamos for the underground nuclear testing program and has also been used in a military mine detection program. The camera uses a solid-state CCD sensor operating at approximately 650 frames per second (75 MPixels per second) with a microchannel plate image intensifier that can provide shuttering as short as 5 ns. The images are captured with a laboratory high-speed digitizer and transferred to an IBM compatible PC for display and hard copy output for analysis. The imaging system is described in this paper.

  1. Numerical Simulation of Flow Instabilities in High Speed Multistage Compressors

    Institute of Scientific and Technical Information of China (English)

    JunHu; ThomasPeters; 等

    1999-01-01

    In the present paper,a nonlinear multi“actuator disk” model is proposed to analyze the dynamic behavior of flow instabilities,including rotating stall and surge,in high speed multistage axial compressors.The model describes the duct flow fields using two dimensional,compressible and unsteady Euler equations,and accounts for the influences of downstream plenum and throttle in the system as well.It replaces each blade row of multistage compressore with a disk.For numerical calculations,the time marching procedure,using MacCormack two steps scheme,is used.The main pupose of this paper is to predict the mechanism of two dimensional short wavelength rotating stall inception and the interation between blade rows in high speed multistage compressors.It has been demonstrated that the model has the ability to predict those phenomena,and the results show that some system parameters have a strong effect on the stall features as well.Results for a five stage high speed compressor are analyzed in detail,and comparison with the experimental data demonstrates that the model and calculating results are reliable.

  2. High speed turbulent reacting flows: DNS and LES

    Science.gov (United States)

    Givi, Peyman

    1990-01-01

    Work on understanding the mechanisms of mixing and reaction in high speed turbulent reacting flows was continued. Efforts, in particular, were concentrated on taking advantage of modern computational methods to simulate high speed turbulent flows. In doing so, two methodologies were used: large eddy simulations (LES) and direct numerical simulations (DNS). In the work related with LES the objective is to study the behavior of the probability density functions (pdfs) of scalar properties within the subgrid in reacting turbulent flows. The data base obtained by DNS for a detailed study of the pdf characteristics within the subgrid was used. Simulations are performed for flows under various initializations to include the effects of compressibility on mixing and chemical reactions. In the work related with DNS, a two-dimensional temporally developing high speed mixing layer under the influence of a second-order non-equilibrium chemical reaction of the type A + B yields products + heat was considered. Simulations were performed with different magnitudes of the convective Mach numbers and with different chemical kinetic parameters for the purpose of examining the isolated effects of the compressibility and the heat released by the chemical reactions on the structure of the layer. A full compressible code was developed and utilized, so that the coupling between mixing and chemical reactions is captured in a realistic manner.

  3. A low power high speed radiation hard serializer for High Energy Physics experiments

    CERN Document Server

    AUTHOR|(CDS)2080243; Marchioro, Alessandro; Ottavi, Marco

    This Ph.D. thesis focuses on the development and the characterization of novel solutions for electronic systems for high-speed data transmission in extremely high radio-active environment (e.g. high energy physics application). The text proposes two alternative full-custom solutions for a fundamental enabling block for a lowpower serial data transmission system, the serializer. This block will find place in a future transceiver conceived for the future upgraded phase of the Large Hadron Collider, or LHC, at CERN. The first solution proposed, called “triple module redundancy”, is based on hardware redundancy, a well-known solution, to obtain protection against the temporary malfunctioning induced by radiation. In the second case a new architecture, called “code protected”, is proposed. This architecture takes advantage of the error correction code present in the data word to obtain radiation robustness on data and some parts of the control logic and to further reduce the power consumption. A test chip ...

  4. The Interaction of High-Speed Turbulence with Flames: Turbulent Flame Speed

    CERN Document Server

    Poludnenko, Alexei Y; 10.1016/j.combustflame.2010.09.002

    2011-01-01

    (Abridged) Direct numerical simulations of the interaction of a premixed flame with driven, subsonic, homogeneous, isotropic, Kolmogorov-type turbulence in an unconfined system are used to study the mechanisms determining the turbulent flame speed, S_T, in the thin reaction zone regime. High intensity turbulence is considered with the r.m.s. velocity 35 times the laminar flame speed, S_L, resulting in the Damkohler number Da = 0.05. Here we show that: (1) The flame brush has a complex internal structure, in which the isosurfaces of higher fuel mass fractions are folded on progressively smaller scales. (2) Global properties of the turbulent flame are best represented by the structure of the region of peak reaction rate, which defines the flame surface. (3) In the thin reaction zone regime, S_T is predominantly determined by the increase of the flame surface area, A_T, caused by turbulence. (4) The observed increase of S_T relative to S_L exceeds the corresponding increase of A_T relative to the surface area of...

  5. Development of High-speed Machining Database with Case-based Reasoning

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Applying high-speed machining technology in shop floor has many benefits, such as manufacturing more accurate parts with better surface finishes. The selection of the appropriate machining parameters plays a very important role in the implementation of high-speed machining technology. The case-based reasoning is used in the developing of high-speed machining database to overcome the shortage of available high-speed cutting parameters in machining data handbooks and shop floors. The high-speed machining data...

  6. Assessment of Gearbox Operational Loads and Reliability under High Mean Wind Speeds

    DEFF Research Database (Denmark)

    Dabrowski, Dariusz; Natarajan, Anand

    2015-01-01

    wind turbine that operates in storm conditions with mean wind speeds less than 30 m/s is presented. In the study, normal shut-downs of a wind turbine in storm conditions were investigated. The analysis were conducted for two storm control strategies and different wind conditions from an extreme...... of the model was based on the experimental data provided by NREL for 750 kW prototype gearbox. Failures of gearboxes caused by high dynamic loads have a significant influence on the cost of operation of wind farms. For these reasons in the study, the probability of failure of the gearbox working in an offshore...... operating gust, normal turbulence model and extreme turbulence model. In the paper, loads in the planetary gear are quantified as well as the torsional moments in the main shaft. On the basis of simulation results the annual probability of failure of the gearbox in a wind turbine with soft storm controller...

  7. High-speed seatbelt pretensioner loading of the abdomen.

    Science.gov (United States)

    Foster, Craig D; Hardy, Warren N; Yang, King H; King, Albert I; Hashimoto, Syuzo

    2006-11-01

    This study characterizes the response of the human cadaver abdomen to high-speed seatbelt loading using pyrotechnic pretensioners. A test apparatus was developed to deliver symmetric loading to the abdomen using a seatbelt equipped with two low-mass load cells. Eight subjects were tested under worst-case scenario, out-of-position (OOP) conditions. A seatbelt was placed at the level of mid-umbilicus and drawn back along the sides of the specimens, which were seated upright using a fixed-back configuration. Penetration was measured by a laser, which tracked the anterior aspect of the abdomen, and by high-speed video. Additionally, aortic pressure was monitored. Three different pretensioner designs were used, referred to as system A, system B and system C. The B and C systems employed single pretensioners. The A system consisted of two B system pretensioners. The vascular systems of the subjects were perfused. Peak anterior abdominal loads due to the seatbelt ranged from 2.8 kN to 10.1 kN. Peak abdominal penetration ranged from 49 mm to 138 mm. Peak penetration speed ranged from 4.0 m/s to 13.3 m/s. Three cadavers sustained liver injury: one AIS 2, and two AIS 3. Cadaver abdominal response corridors for the A and B system pretensioners are proposed. The results are compared to the data reported by Hardy et al. (2001) and Trosseille et al. (2002).

  8. A second-generation high speed civil transport: Stingray

    Science.gov (United States)

    Engdahl, Sean; Lopes, Kevin; Ngan, Angelen; Perrin, Joseph; Phipps, Marcus; Westman, Blake; Yeo, Urn

    1992-01-01

    The Stingray is the second-generation High Speed Civil Transport (HSCT) designed for the 21st Century. This aircraft is designed to be economically viable and environmentally sound transportation competitive in markets currently dominated by subsonic aircraft such as the Boeing 747 and upcoming McDonnell Douglas MD-12. With the Stringray coming into service in 2005, a ticket price of 21 percent over current subsonic airlines will cover operational costs with a 10 percent return on investment. The cost per aircraft will be $202 million with the Direct Operating Cost equal to $0.072 per mile per seat. This aircraft has been designed to be a realistic aircraft that can be built within the next ten to fifteen years. There was only one main technological improvement factor used in the design, that being for the engine specific fuel consumption. The Stingray, therefore, does not rely on technology that does not exist. The Stingray will be powered by four mixed flow turbofans that meet both nitrous oxide emissions and FAR 36 Stage 3 noise regulations. It will carry 250 passengers a distance of 5200 nautical miles at a speed of Mach 2.4. The shape of the Stingray, while optimized for supersonic flight, is compatible with all current airline facilities in airports around the world. As the demand for economical, high-speed flight increases, the Stingray will be ready and able to meet those demands.

  9. High speed digital holographic interferometry for hypersonic flow visualization

    Science.gov (United States)

    Hegde, G. M.; Jagdeesh, G.; Reddy, K. P. J.

    2013-06-01

    Optical imaging techniques have played a major role in understanding the flow dynamics of varieties of fluid flows, particularly in the study of hypersonic flows. Schlieren and shadowgraph techniques have been the flow diagnostic tools for the investigation of compressible flows since more than a century. However these techniques provide only the qualitative information about the flow field. Other optical techniques such as holographic interferometry and laser induced fluorescence (LIF) have been used extensively for extracting quantitative information about the high speed flows. In this paper we present the application of digital holographic interferometry (DHI) technique integrated with short duration hypersonic shock tunnel facility having 1 ms test time, for quantitative flow visualization. Dynamics of the flow fields in hypersonic/supersonic speeds around different test models is visualized with DHI using a high-speed digital camera (0.2 million fps). These visualization results are compared with schlieren visualization and CFD simulation results. Fringe analysis is carried out to estimate the density of the flow field.

  10. Decomposition of forging die for high speed machining

    CERN Document Server

    Tapie, Laurent

    2009-01-01

    Today's forging die manufacturing process must be adapted to several evolutions in machining process generation: CAD/CAM models, CAM software solutions and High Speed Machining (HSM). In this context, the adequacy between die shape and HSM process is in the core of machining preparation and process planning approaches. This paper deals with an original approach of machining preparation integrating this adequacy in the main tasks carried out. In this approach, the design of the machining process is based on two levels of decomposition of the geometrical model of a given die with respect to HSM cutting conditions (cutting speed and feed rate) and technological constrains (tool selection, features accessibility). This decomposition assists machining assistant to generate an HSM process. The result of this decomposition is the identification of machining features.

  11. Unwinding of a carbon nanoscroll due to high speed rotation

    Directory of Open Access Journals (Sweden)

    Hang Yin

    2015-10-01

    Full Text Available A carbon nanoscroll (CNS can be formed easily by rolling a graphene sheet around a carbon nanotube (CNT [Zhang and Li, 2010, APL, 97, 081909]. When the CNS is driven by the rotary CNT to rotate at a high speed, the attractive interaction within the CNS or between the CNS and CNT is crippled by the centrifugal force on the CNS. The unwinding of CNS is triggered when the kinetic energy increment approaches to the variation of interaction energy of the system during CNS formation. Numerical experiments also indicate that the unwinding of CNS happens earlier when the CNT has a higher rotational speed or the system is at a higher temperature.

  12. Marshall Space Flight Center High Speed Turbopump Bearing Test Rig

    Science.gov (United States)

    Gibson, Howard; Moore, Chip; Thom, Robert

    2000-01-01

    The Marshall Space Flight Center has a unique test rig that is used to test and develop rolling element bearings used in high-speed cryogenic turbopumps. The tester is unique in that it uses liquid hydrogen as the coolant for the bearings. This test rig can simulate speeds and loads experienced in the Space Shuttle Main Engine turbopumps. With internal modifications, the tester can be used for evaluating fluid film, hydrostatic, and foil bearing designs. At the present time, the test rig is configured to run two ball bearings or a ball and roller bearing, both with a hydrostatic bearing. The rig is being used to evaluate the lifetimes of hybrid bearings with silicon nitride rolling elements and steel races.

  13. High Speed Gear Sized and Configured to Reduce Windage Loss

    Science.gov (United States)

    Kunz, Robert F. (Inventor); Medvitz, Richard B. (Inventor); Hill, Matthew John (Inventor)

    2013-01-01

    A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

  14. High-speed spectral tuning CARS microscopy using AOTF laser

    Science.gov (United States)

    Hashimoto, Mamoru; Iwatsuka, Junichi; Niioka, Hirohiko; Araki, Tsutomu

    2012-03-01

    We have developed a high speed spectral tuning CARS microscopy system using a mode-locked Ti:Sapphire laser with an acousto-optic tunable filter (AOTF) in the cavity. Since the wavelength of the laser is tunable with the applied radio frequency to the AOTF, the wavelength is electrically tunable.The pulse duration of the laser is about 10 ps, tunable range is 800 nm to 930 nm, and the tuning speed is ms order. The laser is synchronized with another mode-locked Ti:Sapphire laser laser our own method using a balance cross-correlator and phase lock loop technique. The synchronized lasers are used for light source of multi-focus CARS microscopy system using a microlens array scanner, and the hyperspectral imaging of adipocyte cells is demonstrated.

  15. High Speed Boosted Cmos Differential Logic for Ripple Carry Adders

    Directory of Open Access Journals (Sweden)

    Meenu Roy,

    2014-01-01

    Full Text Available This paper describes a high speed boosted CMOS differential logic which is applicable in Ripple Carry Adders. The proposed logic operating with supply voltage approaching the MOS threshold voltage. The logic style improves switching speed by boosting the gate-source voltage of transistors along timing critical signal path. It allows a single boosting circuit to be shared by complementary outputs as a result the area overhead also minimizes. As compared to the conventional logic gates the EDP (energy delay product is improved. The test sets of logic gates and adders where designed in tsmc0.18μm of Mentor Graphics EDA tool. The experimental result for Ripple Carry Adders using the proposed logic style revealed that the addition time is reduced as compared with the conventional CMOS circuits.

  16. High speed coding for velocity by archerfish retinal ganglion cells

    Directory of Open Access Journals (Sweden)

    Kretschmer Viola

    2012-06-01

    Full Text Available Abstract Background Archerfish show very short behavioural latencies in response to falling prey. This raises the question, which response parameters of retinal ganglion cells to moving stimuli are best suited for fast coding of stimulus speed and direction. Results We compared stimulus reconstruction quality based on the ganglion cell response parameters latency, first interspike interval, and rate. For stimulus reconstruction of moving stimuli using latency was superior to using the other stimulus parameters. This was true for absolute latency, with respect to stimulus onset, as well as for relative latency, with respect to population response onset. Iteratively increasing the number of cells used for reconstruction decreased the calculated error close to zero. Conclusions Latency is the fastest response parameter available to the brain. Therefore, latency coding is best suited for high speed coding of moving objects. The quantitative data of this study are in good accordance with previously published behavioural response latencies.

  17. A high-speed BCI based on code modulation VEP

    Science.gov (United States)

    Bin, Guangyu; Gao, Xiaorong; Wang, Yijun; Li, Yun; Hong, Bo; Gao, Shangkai

    2011-04-01

    Recently, electroencephalogram-based brain-computer interfaces (BCIs) have attracted much attention in the fields of neural engineering and rehabilitation due to their noninvasiveness. However, the low communication speed of current BCI systems greatly limits their practical application. In this paper, we present a high-speed BCI based on code modulation of visual evoked potentials (c-VEP). Thirty-two target stimuli were modulated by a time-shifted binary pseudorandom sequence. A multichannel identification method based on canonical correlation analysis (CCA) was used for target identification. The online system achieved an average information transfer rate (ITR) of 108 ± 12 bits min-1 on five subjects with a maximum ITR of 123 bits min-1 for a single subject.

  18. High speed automated microtomography of nuclear emulsions and recent application

    Energy Technology Data Exchange (ETDEWEB)

    Tioukov, V.; Aleksandrov, A.; Consiglio, L. [INFN Napoli (Italy); De Lellis, G. [Universita di Napoli (Italy); Vladymyrov, M. [LPI Moscow (Russian Federation)

    2015-12-31

    The development of high-speed automatic scanning systems was the key-factor for massive and successful emulsions application for big neutrino experiments like OPERA. The emulsion detector simplicity, the unprecedented sub-micron spatial resolution and the unique ability to provide intrinsically 3-dimensional spatial information make it a perfect device for short-living particles study, where the event topology should be precisely reconstructed in a 10-100 um scale vertex region. Recently the exceptional technological progress in image processing and automation together with intensive R&D done by Italian and Japanese microscopy groups permit to increase the scanning speed to unbelievable few years ago m{sup 2}/day scale and so greatly extend the range of the possible applications for emulsion-based detectors to other fields like: medical imaging, directional dark matter search, nuclear physics, geological and industrial applications.

  19. Containment of high-speed rotating disk fragments

    Institute of Scientific and Technical Information of China (English)

    Hai-jun XUAN; Lu-lu LIU; Yi-ming FENG; Qing HE; Juan-juan LI

    2012-01-01

    Disk burst accidents sometimes happen in aeroengines.To avoid tragic consequences,aeroengine casings must have sufficient containment capability.Experiments and simulations need to be conducted to study the impact,distortion,and perforation caused by disk burst and which may give important clues to potential failure mechanisms.This paper presents some containment tests of high-speed rotating disk fragments,in which the original disks were burst into three equal fragments within a predetermined rotating speed range.The failure modes of the containment casing varied significantly with the thickness of the containment casing.Shearing,tearing,tensile fracture,and large plastic stretching deformation occurred in a thin-walled containment casing,while a thick-walled casing could contain disk fragments and withstand large plastic deformation.Numerical simulations were carried out to study the impact process and failure modes further.Good agreement was found between the results of the simulations and the tests.

  20. Implementation of High Speed Distributed Data Acquisition System

    Science.gov (United States)

    Raju, Anju P.; Sekhar, Ambika

    2012-09-01

    This paper introduces a high speed distributed data acquisition system based on a field programmable gate array (FPGA). The aim is to develop a "distributed" data acquisition interface. The development of instruments such as personal computers and engineering workstations based on "standard" platforms is the motivation behind this effort. Using standard platforms as the controlling unit allows independence in hardware from a particular vendor and hardware platform. The distributed approach also has advantages from a functional point of view: acquisition resources become available to multiple instruments; the acquisition front-end can be physically remote from the rest of the instrument. High speed data acquisition system transmits data faster to a remote computer system through Ethernet interface. The data is acquired through 16 analog input channels. The input data commands are multiplexed and digitized and then the data is stored in 1K buffer for each input channel. The main control unit in this design is the 16 bit processor implemented in the FPGA. This 16 bit processor is used to set up and initialize the data source and the Ethernet controller, as well as control the flow of data from the memory element to the NIC. Using this processor we can initialize and control the different configuration registers in the Ethernet controller in a easy manner. Then these data packets are sending to the remote PC through the Ethernet interface. The main advantages of the using FPGA as standard platform are its flexibility, low power consumption, short design duration, fast time to market, programmability and high density. The main advantages of using Ethernet controller AX88796 over others are its non PCI interface, the presence of embedded SRAM where transmit and reception buffers are located and high-performance SRAM-like interface. The paper introduces the implementation of the distributed data acquisition using FPGA by VHDL. The main advantages of this system are high

  1. High-speed and high-fidelity system and method for collecting network traffic

    Science.gov (United States)

    Weigle, Eric H.

    2010-08-24

    A system is provided for the high-speed and high-fidelity collection of network traffic. The system can collect traffic at gigabit-per-second (Gbps) speeds, scale to terabit-per-second (Tbps) speeds, and support additional functions such as real-time network intrusion detection. The present system uses a dedicated operating system for traffic collection to maximize efficiency, scalability, and performance. A scalable infrastructure and apparatus for the present system is provided by splitting the work performed on one host onto multiple hosts. The present system simultaneously addresses the issues of scalability, performance, cost, and adaptability with respect to network monitoring, collection, and other network tasks. In addition to high-speed and high-fidelity network collection, the present system provides a flexible infrastructure to perform virtually any function at high speeds such as real-time network intrusion detection and wide-area network emulation for research purposes.

  2. Tactile shoe inlays for high speed pressure monitoring

    DEFF Research Database (Denmark)

    Drimus, Alin; Mátéfi-Tempfli, Stefan

    2015-01-01

    pressure sensitive cells and the use of high speed electronics and multiplexing algorithms provides frame rates of 100 Hz. The sensors tolerate overloads while showing a consistent output. The developed prototypes show a high potential not only for robotics, but also for use in sensorised human prosthetics.......This work describes the development of flexible tactile sensor shoe inlays for humanoid robots. Their design is based on a sandwich structure of flexible layers with a thin sheet of piezoresistive rubber as main transducer element. The layout and patterning of top and bottom electrodes give 1024...

  3. The Impact of High Speed Machining on Computing and Automation

    Institute of Scientific and Technical Information of China (English)

    KKB Hon; BT Hang Tuah Baharudin

    2006-01-01

    Machine tool technologies, especially Computer Numerical Control (CNC) High Speed Machining (HSM) have emerged as effective mechanisms for Rapid Tooling and Manufacturing applications. These new technologies are attractive for competitive manufacturing because of their technical advantages, i.e. a significant reduction in lead-time, high product accuracy, and good surface finish. However, HSM not only stimulates advancements in cutting tools and materials, it also demands increasingly sophisticated CAD/CAM software, and powerful CNC controllers that require more support technologies. This paper explores the computational requirement and impact of HSM on CNC controller, wear detection,look ahead programming, simulation, and tool management.

  4. III-V alloy heterostructure high speed avalanche photodiodes

    Science.gov (United States)

    Law, H. D.; Nakano, K.; Tomasetta, L. R.

    1979-01-01

    Heterostructure avalanche photodiodes have been successfully fabricated in several III-V alloy systems: GaAlAs/GaAs, GaAlSb/GaAlSb, and InGaAsP/InP. These diodes cover optical wavelengths from 0.4 to 1.8 micron. Early stages of development show very encouraging results. High speed response of less than 35 ps and high quantum efficiency more than 95 percent have been obtained. The dark currents and the excess avalanche noise are also dicussed. A direct comparison of GaAlSb, GaAlAsSb, and In GaAsP avalanche photodiodes is given.

  5. Signal Conditioning in Process of High Speed Imaging

    Directory of Open Access Journals (Sweden)

    Libor Hargas

    2015-01-01

    Full Text Available The accuracy of cinematic analysis with camera system depends on frame rate of used camera. Specific case of cinematic analysis is in medical research focusing on microscopic objects moving with high frequencies (cilia of respiratory epithelium. The signal acquired by high speed video acquisition system has very amount of data. This paper describes hardware parts, signal condition and software, which is used for image acquiring thru digital camera, intelligent illumination dimming hardware control and ROI statistic creation. All software parts are realized as virtual instruments.

  6. The high-speed after pulse measurement system for PMT

    CERN Document Server

    Cheng, Yaping; Ning, Zhe; Xia, Jingkai; Wang, Wenwen; Wang, Yifang; Cao, Jun; Jiang, Xiaoshan; Wang, Zheng; Li, Xiaonan; Qi, Ming; Heng, Yuekun; Liu, Shulin; Lei, Xiangcui; Wu, Zhi

    2014-01-01

    A system employing a desktop FADC has been developed to investigate the features of 8 inches Hamamatsu PMT. The system stands out for its high-speed and informative results as a consequence of adopting fast waveform sampling technology. Recording full waveforms allows us to perform digital signal processing, pulse shape analysis, and precision timing extraction. High precision after pulse time and charge distribution characteristics are presented in this manuscript. Other photomultipliers characteristics, such as dark rate and transit time spread, can also be obtained by exploiting waveform analysis using this system.

  7. Hunting For Eclipses: High Speed Observations of Cataclysmic Variables

    CERN Document Server

    Hardy, Liam K; Dhillon, Vik S; Littlefair, Stuart P; Bours, Madelon C P; Breedt, Elme; Butterley, Tim; Chakpor, Anurak; Irawati, Puji; Kerry, Paul; Marsh, Tom R; Parsons, Steven G; Savoury, Chris D J; Wilson, Richard W; Woudt, Patrick A

    2016-01-01

    We present new time-resolved photometry of 74 cataclysmic variables (CVs), 47 of which are eclipsing. 13 of these eclipsing systems are newly discovered. For all 47 eclipsing systems we show high cadence (1-20 seconds) 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 which appear to be suitable for future study.

  8. Ping-Pong Robotics with High-Speed Vision System

    OpenAIRE

    Li, Hailing; Wu, Haiyan; Lou, Lei; Kühnlenz, Kolja; Ravn, Ole

    2012-01-01

    The performance of vision-based control is usually limited by the low sampling rate of the visual feedback. We address Ping-Pong robotics as a widely studied example which requires high-speed vision for highly dynamic motion control. Inorder to detect a flying ball accurately and robustly, a multithreshold legmentation algorithm is applied in a stereo-vision running at 150Hz. Based on the estimated 3D ball positions, a novel two-phase trajectory prediction is exploited to determine the hittin...

  9. Extremely High Current, High-Brightness Energy Recovery Linac

    CERN Document Server

    Ben-Zvi, Ilan; Beavis, Dana; Blaskiewicz, Michael; Bluem, Hans; Brennan, Joseph M; Burger, Al; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Chang, Xiangyun; Cole, Michael; Connolly, Roger; Delayen, Jean R; Favale, Anthony; Gassner, David M; Grimes, Jacob T; Hahn, Harald; Hershcovitch, Ady; Holmes, Douglas; Hseuh Hsiao Chaun; Johnson, Peter; Kayran, Dmitry; Kewisch, Jorg; Kneisel, Peter; Lambiase, Robert; Litvinenko, Vladimir N; McIntyre, Gary; Meng, Wuzheng; Nehring, Thomas; Nicoletti, Tony; Oerter, Brian; Pate, David; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Roser, Thomas; Russo, Thomas; Scaduto, Joseph; Schultheiss, Tom; Segalov, Zvi; Smith, Kevin T; Todd, Alan M M; Warren-Funk, L; Williams, Neville; Wu, Kuo-Chen; Yakimenko, Vitaly; Yip, Kin; Zaltsman, Alex; Zhao, Yongxiang

    2005-01-01

    Next generation ERL light-sources, high-energy electron coolers, high-power Free-Electron Lasers, powerful Compton X-ray sources and many other accelerators were made possible by the emerging technology of high-power, high-brightness electron beams. In order to get the anticipated performance level of ampere-class currents, many technological barriers are yet to be broken. BNL's Collider-Accelerator Department is pursuing some of these technologies for its electron cooling of RHIC application, as well as a possible future electron-hadron collider. We will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun and an accelerator cavity capable of producing low emittance (about 1 micron rms normalized) one nano-Coulomb bunches at currents of the order of one ampere average.

  10. Fusion: ultra-high-speed and IR image sensors

    Science.gov (United States)

    Etoh, T. Goji; Dao, V. T. S.; Nguyen, Quang A.; Kimata, M.

    2015-08-01

    Most targets of ultra-high-speed video cameras operating at more than 1 Mfps, such as combustion, crack propagation, collision, plasma, spark discharge, an air bag at a car accident and a tire under a sudden brake, generate sudden heat. Researchers in these fields require tools to measure the high-speed motion and heat simultaneously. Ultra-high frame rate imaging is achieved by an in-situ storage image sensor. Each pixel of the sensor is equipped with multiple memory elements to record a series of image signals simultaneously at all pixels. Image signals stored in each pixel are read out after an image capturing operation. In 2002, we developed an in-situ storage image sensor operating at 1 Mfps 1). However, the fill factor of the sensor was only 15% due to a light shield covering the wide in-situ storage area. Therefore, in 2011, we developed a backside illuminated (BSI) in-situ storage image sensor to increase the sensitivity with 100% fill factor and a very high quantum efficiency 2). The sensor also achieved a much higher frame rate,16.7 Mfps, thanks to the wiring on the front side with more freedom 3). The BSI structure has another advantage that it has less difficulties in attaching an additional layer on the backside, such as scintillators. This paper proposes development of an ultra-high-speed IR image sensor in combination of advanced nano-technologies for IR imaging and the in-situ storage technology for ultra-highspeed imaging with discussion on issues in the integration.

  11. Development of centrifugal casting high speed steel rolls

    Institute of Scientific and Technical Information of China (English)

    Hanguang Fu; Aimin Zhao; Jiandong Xing

    2003-01-01

    The present study aims at developing the high speed steel (HSS) as roll materials to replace the traditional roll materials such as the alloy cast iron and powder metallurgical (PM) hard alloy. The HSS roll billet was formed by centrifugal casting, and the billet was rough machined after soften annealing heat treatment, then it was quenched and tempered to get suitable hardness and toughness. After that the HSS roll was finish machined to the final dimension of φ285 mm in the outer diameter, φ160 mm in the inner diameter and 120 mm in width and its surface hardness was tested. Finally the HSS roll was used in high speed wire rod mill. The test results show that a high and homogeneous hardness can obtain on the work surface of HSS rolls, the surface hardness is 63-65HRC and its variation is smaller than 2HRC. The impact toughness of this kind of HSS is about 16 J/cra2. The results of on-line service investigation in high speed wire rod mill indicate that the HSS rolls have excellent wear resistance, the steel rolling quantity per mm of HSS rolls is 3120 t, the service life-span of HSS rolls is 4 times longer than that of high chromium cast iron rolls and it is close to that of the PM hard alloy rolls. The manufacturing burden of HSS rolls is obviously lower than that of the PM hard alloy rolls, it is only 25% of that of the PM hard alloy rolls.

  12. High Speed and High Resolution Table-Top Nanoscale Imaging

    CERN Document Server

    Tadesse, G K; Demmler, S; HÄdrich, S; Wahyutama, I; Steinert, M; Spielmann, C; ZÜrch, M; TÜnnermann, A; Limpert, J; Rothhardt, J

    2016-01-01

    We present a table-top coherent diffraction imaging (CDI) experiment based on high-order harmonics generated at 18 nm by a high average power femtosecond fiber laser system. The high photon flux, narrow spectral bandwidth and high degree of spatial coherence allow for ultra-high sub-wavelength resolution imaging at a high numerical aperture. Our experiments demonstrate a half-pitch resolution of 13.6 nm, very close to the actual Abbe-limit of 12.4 nm, which is the highest resolution achieved from any table-top XUV or X-ray microscope. In addition, 20.5 nm resolution was achieved with only 3 sec of integration time bringing live diffraction imaging and 3D tomography on the nanoscale one step closer to reality. The current resolution is solely limited by the wavelength and the detector size. Thus, table-top nanoscopes with only a few-nm resolutions are in reach and will find applications in many areas of science and technology.

  13. ULTRA HIGH SPEED FACTORIAL DESIGN IN SUB-NANOMETER TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Arindam Banerjee

    2013-02-01

    Full Text Available This work proposes a high speed and low power factorial design in 22nm technology and also it counts the effect of sub nano-meter constraints on this circuit. A comparative study for this design has been done for 90nm, 45nm and 22nm technology. The rise in circuit complexity and speed is accompanied by the scaling of MOSFET’s. The transistor saturation current Idsat is an important parameter because the transistor current determines the time needed to charge and discharge the capacitive loads on chip, and thus impacts the product speed more than any other transistor parameter. The efficient implementation of a factorial number is carried out by using a decremented and multipliers which has been lucidly discussed in this paper. Normally in a factorial module a number is calculated as the iterative multiplication of the given number to the decremented value of the given number. A Parallel adder based decremented has been proposed for calculating the factorial of any number that also includes 0 and 1. The performances are calculated by using the existing 90-nm CMOS technology and scaling down the existing technology to 45-nm and 22-nm.

  14. High speed superconducting flywheel system for energy storage

    Science.gov (United States)

    Bornemann, H. J.; Urban, C.; Boegler, P.; Ritter, T.; Zaitsev, O.; Weber, K.; Rietschel, H.

    1994-12-01

    A prototype of a flywheel system with auto stable high temperature superconducting bearings was built and tested. The bearings offered good vertical and lateral stability. A metallic flywheel disk, ø 190 mm x 30 mm, was safely rotated at speeds up to 15000 rpm. The disk was driven by a 3 phase synchronous homopolar motor/generator. Maximum energy capacity was 3.8 Wh, maximum power was 1.5 KW. The dynamic behavior of the prototype was tested, characterized and evaluated with respect to axial and lateral stiffness, decay torques (bearing drag), vibrational modes and critical speeds. The bearings supports a maximum weight of 65 N at zero gap, axial and lateral stiffness at 1 mm gap were 440 N/cm and 130 N/cm, respectively. Spin down experiments were performed to investigate the energy efficiency of the system. The decay rate was found to depend upon background pressure in the vacuum chamber and upon the gap width in the bearing. At a background pressure of 5x10 -4 Torr, the coefficient of friction (drag-to-lift ratio) was measured to be 0.000009 at low speeds for 6 mm gap width in the bearing. Our results indicate that further refinement of this technology will allow operation of higly efficient superconducting flywheels in the kWh range.

  15. Development of a Large Scale, High Speed Wheel Test Facility

    Science.gov (United States)

    Kondoleon, Anthony; Seltzer, Donald; Thornton, Richard; Thompson, Marc

    1996-01-01

    Draper Laboratory, with its internal research and development budget, has for the past two years been funding a joint effort with the Massachusetts Institute of Technology (MIT) for the development of a large scale, high speed wheel test facility. This facility was developed to perform experiments and carry out evaluations on levitation and propulsion designs for MagLev systems currently under consideration. The facility was developed to rotate a large (2 meter) wheel which could operate with peripheral speeds of greater than 100 meters/second. The rim of the wheel was constructed of a non-magnetic, non-conductive composite material to avoid the generation of errors from spurious forces. A sensor package containing a multi-axis force and torque sensor mounted to the base of the station, provides a signal of the lift and drag forces on the package being tested. Position tables mounted on the station allow for the introduction of errors in real time. A computer controlled data acquisition system was developed around a Macintosh IIfx to record the test data and control the speed of the wheel. This paper describes the development of this test facility. A detailed description of the major components is presented. Recently completed tests carried out on a novel Electrodynamic (EDS) suspension system, developed by MIT as part of this joint effort are described and presented. Adaptation of this facility for linear motor and other propulsion and levitation testing is described.

  16. High-speed Flight in an Ergodic Forest

    CERN Document Server

    Karaman, Sertac

    2012-01-01

    Inspired by birds flying through cluttered environments such as dense forests, this paper studies the theoretical foundations of a novel motion planning problem: high-speed navigation through a randomly-generated obstacle field when only the statistics of the obstacle generating process are known a priori. Resembling a planar forest environment, the obstacle generating process is assumed to determine the locations and sizes of disk-shaped obstacles. When this process is ergodic, and under mild technical conditions on the dynamics of the bird, it is shown that the existence of an infinite collision-free trajectory through the forest exhibits a phase transition. On one hand, if the bird flies faster than a certain critical speed, then, with probability one, there is no infinite collision-free trajectory, i.e., the bird will eventually collide with some tree, almost surely, regardless of the planning algorithm governing the bird's motion. On the other hand, if the bird flies slower than this critical speed, then...

  17. Fluid durability in a high speed electro-rheological clutch

    Science.gov (United States)

    Johnson, A. R.; Makin, J.; Bullough, W. A.; Firoozian, R.; Hosseini-Sianaki, A.

    1993-10-01

    The durability of an electro-rheological (ER) fluid was investigated by running a high speed ER clutch under different conditions and periods of operation. The tests involved running the clutch at 3000 rpm for a total period of twelve hours over a five day period. The tests subjected the fluid to a centripetal acceleration of 3000 m/sq s, and were conducted with and without an excitation field of 2 kV/mm, and with and without shearing the fluid at shear rates up to 9500/s. The condition of the fluid was assessed periodically by measuring the torque response of the clutch to a step application of voltage in respect of both magnitude and speed of response. Results at the two pole 50 Hz synchronous speed of 3000 rpm indicated that the particles in the fluid were centrifuged over the prolonged test periods. The application of a voltage across the fluid had a negligible effect on this particle migration. The effect of particle migration due to centrifugal and electro-static effects indicate future development requirements for these smart materials.

  18. High speed imaging with CW THz for security

    Science.gov (United States)

    Song, Qian; Redo-Sanchez, Albert; Zhao, Yuejin; Zhang, Cunlin

    2008-12-01

    Continuous THz wave (CW THz) has been widely used in imaging field. But for security screening such as inspection at the airport, the speed of the imaging calls for an improvement since the former CW image systems which scan point to point could not satisfy. To increase the image speed, we proposed a fast CW THz image system in which a galvanometer is introduced for the first time. The galvanometer makes the coming beam reflected in different angles by vibrating at a certain frequency which can significantly decrease the image acquisition time compare to point scan THz imaging. A big hyperbolic polyethylene lens is also used in the system to collect all the beams on to the target. A Gunn oscillator and a corresponding Schottky diode are the source and detector respectively. The image we get has ideal resolution. And after image processing, the images looked not only clear but also realistic. The system has more practicality because it is designed in reflection geometry instead of transmission geometry. Moreover, the source and detector in our system do not as ponderous as gas laser which has been used in many THz imaging system previously. Example of measurements of weapons concealed behind the cloth and box are presented and discussed. A compact high speed THz imaging system is expectable which will have a widely application in security field.

  19. Characteristics of extreme ultraviolet emission from high-Z plasmas

    Science.gov (United States)

    Ohashi, H.; Higashiguchi, T.; Suzuki, Y.; Kawasaki, M.; Suzuki, C.; Tomita, K.; Nishikino, M.; Fujioka, S.; Endo, A.; Li, B.; Otsuka, T.; Dunne, P.; O'Sullivan, G.

    2016-03-01

    We demonstrate the extreme ultraviolet (EUV) and soft x-ray sources in the 2 to 7 nm spectral region related to the beyond EUV (BEUV) question at 6.x nm and the water window source based on laser-produced high-Z plasmas. Resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs), extending below the carbon K edge (4.37 nm). An outline of a microscope design for single-shot live cell imaging is proposed based on high-Z plasma UTA source, coupled to multilayer mirror optics.

  20. A study on centrifugal casting of high speed steel roll

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    High speed steel (HSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, HSS rolls having excellent wear resistance have been manufactured. The hardness of the HSS roll is 65~ 67 HRC, the range of variation is smaller than 2 HRC and its impact toughness is 15 J/cm2. The wear rate of HSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5 × 10-4 mm per ton steel. Furthermore, the manufacturing cost of HSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.

  1. MHD Modelling of Coronal Loops: Injection of High-Speed Chromospheric Flows

    Science.gov (United States)

    Petralia, A.; Reale, F.; Orlando, S.; Klimchuk, J. A.

    2014-01-01

    Context. Observations reveal a correspondence between chromospheric type II spicules and bright upward-moving fronts in the corona observed in the extreme-ultraviolet (EUV) band. However, theoretical considerations suggest that these flows are probably not the main source of heating in coronal magnetic loops. Aims. We investigate the propagation of high-speed chromospheric flows into coronal magnetic flux tubes and the possible production of emission in the EUV band. Methods. We simulated the propagation of a dense 104 K chromospheric jet upward along a coronal loop by means of a 2D cylindrical MHD model that includes gravity, radiative losses, thermal conduction, and magnetic induction. The jet propagates in a complete atmosphere including the chromosphere and a tenuous cool (approximately 0.8 MK) corona, linked through a steep transition region. In our reference model, the jet initial speed is 70 km per second, its initial density is 10(exp 11) per cubic centimeter, and the ambient uniform magnetic field is 10 G. We also explored other values of jet speed and density in 1D and different magnetic field values in 2D, as well as the jet propagation in a hotter (approximately 1.5 MK) background loop. Results. While the initial speed of the jet does not allow it to reach the loop apex, a hot shock-front develops ahead of it and travels to the other extreme of the loop. The shock front compresses the coronal plasma and heats it to about 10(exp 6) K. As a result, a bright moving front becomes visible in the 171 Angstrom channel of the SDO/AIA mission. This result generally applies to all the other explored cases, except for the propagation in the hotter loop. Conclusions. For a cool, low-density initial coronal loop, the post-shock plasma ahead of upward chromospheric flows might explain at least part of the observed correspondence between type II spicules and EUV emission excess.

  2. Flow Analysis By High Speed Photography And Pictures

    Science.gov (United States)

    Werle, H.

    1985-02-01

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

  3. High-sensitivity, high-speed continuous imaging system

    Science.gov (United States)

    Watson, Scott A; Bender, III, Howard A

    2014-11-18

    A continuous imaging system for recording low levels of light typically extending over small distances with high-frame rates and with a large number of frames is described. Photodiode pixels disposed in an array having a chosen geometry, each pixel having a dedicated amplifier, analog-to-digital convertor, and memory, provide parallel operation of the system. When combined with a plurality of scintillators responsive to a selected source of radiation, in a scintillator array, the light from each scintillator being directed to a single corresponding photodiode in close proximity or lens-coupled thereto, embodiments of the present imaging system may provide images of x-ray, gamma ray, proton, and neutron sources with high efficiency.

  4. High-speed signal processing using highly nonlinear optical fibres

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen

    2009-01-01

    relying on the phase of the optical field. Topics covered include all-optical switching of 640 Gbit/s and 1.28 Tbit/s serial data, wavelength conversion at 640 Gbit/s, optical amplitude regeneration of differential phase shift keying (DPSK) signals, as well as midspan spectral inversion for differential 8......We review recent progress in all-optical signal processing techniques making use of conventional silica-based highly nonlinear fibres. In particular, we focus on recent demonstrations of ultra-fast processing at 640 Gbit/s and above, as well as on signal processing of novel modulation formats...

  5. Aeroelastic Calculations of Quiet High- Speed Fan Performed

    Science.gov (United States)

    Bakhle, Milind A.; Srivastava, Rakesh; Mehmed, Oral; Min, James B.

    2002-01-01

    An advanced high-speed fan was recently designed under a cooperative effort between the NASA Glenn Research Center and Honeywell Engines & Systems. The principal design goals were to improve performance and to reduce fan noise at takeoff. Scale models of the Quiet High-Speed Fan were tested for operability, performance, and acoustics. During testing, the fan showed significantly improved noise characteristics, but a self-excited aeroelastic vibration known as flutter was encountered in the operating range. Flutter calculations were carried out for the Quiet High-Speed Fan using a three-dimensional, unsteady aerodynamic, Reynolds-averaged Navier-Stokes turbomachinery code named "TURBO." The TURBO code can accurately model the viscous flow effects that can play an important role in various aeroelastic problems such as flutter with flow separation, flutter at high loading conditions near the stall line (stall flutter), and flutter in the presence of shock and boundary-layer interaction. Initially, calculations were performed with no blade vibrations. These calculations were at a constant rotational speed and a varying mass flow rate. The mass flow rate was varied by changing the backpressure at the exit boundary of the computational domain. These initial steady calculations were followed by aeroelastic calculations in which the blades were prescribed to vibrate harmonically in a natural mode, at a natural frequency, and with a fixed interblade phase angle between adjacent blades. The AE-prep preprocessor was used to interpolate the in-vacuum mode shapes from the structural dynamics mesh onto the computational fluid dynamics mesh and to smoothly propagate the grid deformations from the blade surface to the interior points of the grid. The aeroelastic calculations provided the unsteady aerodynamic forces on the blade surface due to blade vibrations. These forces were vector multiplied with the structural dynamic mode shape to calculate the work done on the blade during

  6. Magnetic Bearing Controller Improvements for High Speed Flywheel System

    Science.gov (United States)

    Dever, Timothy P.; Brown, Gerald V.; Jansen, Ralph H.; Kascak, Peter E.; Provenza, Andrew J.

    2003-01-01

    A magnetic bearing control system for a high-speed flywheel system is described. The flywheel utilizes a five axis active magnetic bearing system, using eddy current sensors for position feedback to the bearing controller. Magnetic bearing controller features designed to improve flywheel operation and testing are described. Operational improvements include feed forward control to compensate for rotor imbalance, moving notch filtering to compensate for synchronous and harmonic rotational noise, and fixed notching to prevent rotor bending mode excitation. Testing improvements include adding safe gain, bearing current hold, bearing current zero, and excitation input features. Performance and testing improvements provided by these features are measured and discussed.

  7. Stereoscopic high-speed imaging using additive colors

    Science.gov (United States)

    Sankin, Georgy N.; Piech, David; Zhong, Pei

    2012-04-01

    An experimental system for digital stereoscopic imaging produced by using a high-speed color camera is described. Two bright-field image projections of a three-dimensional object are captured utilizing additive-color backlighting (blue and red). The two images are simultaneously combined on a two-dimensional image sensor using a set of dichromatic mirrors, and stored for off-line separation of each projection. This method has been demonstrated in analyzing cavitation bubble dynamics near boundaries. This technique may be useful for flow visualization and in machine vision applications.

  8. II-IV-V2 Chalcopyrites for High Speed Devices.

    Science.gov (United States)

    1982-07-31

    fabrication to of suitable device structures; and (5) investigate novel high-speed device concepts which could utilize the unique properties of these chalco ...semi- conductor material. CdSnP2 and ZnSnP2 are crystals which grow with the chalco - pyrite lattice structure shown in Figure 1. This structure re...parameters, chalco - pyrites differing from CdSnP2 in only one constituent were reviewed for the alloy system. ZnSnP2, CdSiP2 , and CdGeP2 are all

  9. Grooved roll for a high speed twin roll caster

    OpenAIRE

    T. Haga; HIROOKA, K.; H. Watari; S. Kumai

    2008-01-01

    Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings ...

  10. "EFFECTS OF HIGH-SPEED DRILL NOISE ON DENTISTS’ HEARING "

    Directory of Open Access Journals (Sweden)

    F.Akbakhanzadeh

    1978-11-01

    Full Text Available The study deals with noise problems associated with the use of air-turbine drills in dental practice. Noise level measurements were made on various types of dental handpieces, when operated free running and when used to cut tooth tissue. Hearing acuity tests were also undertaken in 12 randomly selected dental surgeons who have been using these drills for a number of years. The results indicate that although the danger to hearing from high speed drills is small, the possibility of hazardous effects-at least, for susceptible ears- is not excluded.

  11. High-Speed Low Power Design in CMOS

    DEFF Research Database (Denmark)

    Ghani, Arfan; Usmani, S. H.; Stassen, Flemming

    2004-01-01

    Static CMOS design displays benefits such as low power consumption, dominated by dynamic power consumption. In contrast, MOS Current Mode Logic (MCML) displays static rather than dynamic power consumption. High-speed low-power design is one of the many application areas in VLSI that require...... the theorethical description of MOS Current Mode Logic, and it is found that it is more difficult to model and simulate the circuit with compare to standard CMOS because of the differential inputs and low voltage swing....

  12. MOTION VELOCITY SMOOTH LINK IN HIGH SPEED MACHINING

    Institute of Scientific and Technical Information of China (English)

    REN Kun; FU Jianzhong; CHEN Zichen

    2007-01-01

    To deal with over-shooting and gouging in high speed machining, a novel approach for velocity smooth link is proposed. Considering discrete tool path, cubic spline curve fitting is used to find dangerous points, and according to spatial geometric properties of tool path and the kinematics theory, maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system, a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves productivity greatly.

  13. High Speed Optical Tomography System for Imaging Dynamic Transparent Media

    Science.gov (United States)

    McMackin, Lenore; Hugo, Ronald J.; Pierson, R. E.; Truman, C. R.

    1997-11-01

    We describe the design and operation of a high speed optical tomography system for measuring two-dimensional images of a dynamic phase object at a rate of 5 kHz. Data from a set of eight Hartmann wavefront sensors is back-projected to produce phase images showing the details of the inner structure of a heated air flow. The tomographic reconstructions have a spatial resolution of approximately 2.0 mm and can measure temperature variations across the flow with an accuracy of about 0.7 C. Series of animated reconstructions at different downstream locations illustrate the development of flow structure and the effect of acoustic flow forcing.

  14. High-speed schlieren imaging of rocket exhaust plumes

    Science.gov (United States)

    Coultas-McKenney, Caralyn; Winter, Kyle; Hargather, Michael

    2016-11-01

    Experiments are conducted to examine the exhaust of a variety of rocket engines. The rocket engines are mounted in a schlieren system to allow high-speed imaging of the engine exhaust during startup, steady state, and shutdown. A variety of rocket engines are explored including a research-scale liquid rocket engine, consumer/amateur solid rocket motors, and water bottle rockets. Comparisons of the exhaust characteristics, thrust and cost for this range of rockets is presented. The variety of nozzle designs, target functions, and propellant type provides unique variations in the schlieren imaging.

  15. Study on Electromagnetic Interference of high-speed railway EMU

    Directory of Open Access Journals (Sweden)

    CHENG Qiang

    2013-07-01

    Full Text Available Electromagnetic radiation generated by pantograph-catenaries detachment is one of the inevitable problems with the development of high-speed railway this paper is focusing on the generating mechanism and characteristics of electromagnetic noise caused by pantograph-catenaries system. Based on previous research, we build an integrated model of catenaries and locomotive system, and study the electromagnetic disturbance characteristics using software FEKO. The simulation experiment results in the end can not only provide accurate data, but also give a more intuitive understanding of electromagnetic field distribution and attenuation characteristics generated by pantograph detachment.    

  16. Bottom Raking Damage to High-Speed Craft

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1998-01-01

    This paper presents a comparative study of the raking damage to high speed craft (HSC) and conventional ships. The analysis is based on a detailed theoretical model for the raking resistance of an assembled ship bottom structure and on the idea that the impact conditions for various ship types have...... certain similarities. Thus, damage statistics for one ship type can be scaled to another ship type.The result of a raking damage calculation is sensitive to various uncertain parameters, such as the impact velocity and the rock height and shape. Conveniently, the paper shows that the damage scaling factor...

  17. High-speed multicolor photometry with CMOS cameras

    CERN Document Server

    Pokhvala, S M; Reshetnyk, V M

    2012-01-01

    We present the results of testing the commercial digital camera Nikon D90 with a CMOS sensor for high-speed photometry with a small telescope Celestron 11" on Peak Terskol. CMOS sensor allows to perform photometry in 3 filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR color system of CMOS sensors is close to the Johnson BVR system. The results of testing show that we can measure the stars up to V $\\simeq$ 14 with the precision of 0.01 mag. Stars up to magnitude V $\\sim$ 10 can shoot at 24 frames per second in the video mode.

  18. New technique for high-speed microjet breakup analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vago, N. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Synova SA, Ch. Dent d' Oche, 1024 Ecublens (Switzerland); Spiegel, A. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Couty, P. [Institute of Imaging and Applied Optics, Swiss Federal Institute of Technology, Lausanne, BM, 1015, Lausanne (Switzerland); Wagner, F.R.; Richerzhagen, B. [Synova SA, Ch. Dent d' Oche, 1024 Ecublens (Switzerland)

    2003-10-01

    In this paper we introduce a new technique for visualizing the breakup of thin high-speed liquid jets. Focused light of a He-Ne laser is coupled into a water jet, which behaves as a cylindrical waveguide until the point where the amplitude of surface waves is large enough to scatter out the light from the jet. Observing the jet from a direction perpendicular to its axis, the light that appears indicates the location of breakup. Real-time examination and also statistical analysis of the jet disruption is possible with this method. A ray tracing method was developed to demonstrate the light scattering process. (orig.)

  19. Reflectively Coupled Waveguide Photodetector for High Speed Optical Interconnection

    Directory of Open Access Journals (Sweden)

    Shih-Hsiang Hsu

    2010-12-01

    Full Text Available To fully utilize GaAs high drift mobility, techniques to monolithically integrate In0.53Ga0.47As p-i-n photodetectors with GaAs based optical waveguides using total internal reflection coupling are reviewed. Metal coplanar waveguides, deposited on top of the polyimide layer for the photodetector’s planarization and passivation, were then uniquely connected as a bridge between the photonics and electronics to illustrate the high-speed monitoring function. The photodetectors were efficiently implemented and imposed on the echelle grating circle for wavelength division multiplexing monitoring. In optical filtering performance, the monolithically integrated photodetector channel spacing was 2 nm over the 1,520–1,550 nm wavelength range and the pass band was 1 nm at the −1 dB level. For high-speed applications the full-width half-maximum of the temporal response and 3-dB bandwidth for the reflectively coupled waveguide photodetectors were demonstrated to be 30 ps and 11 GHz, respectively. The bit error rate performance of this integrated photodetector at 10 Gbit/s with 27-1 long pseudo-random bit sequence non-return to zero input data also showed error-free operation.

  20. High speed and wide bandwidth delta-sigma ADCs

    CERN Document Server

    Bolatkale, Muhammed; Makinwa, Kofi A A

    2014-01-01

    This book describes techniques for realizing wide bandwidth (125MHz) over-sampled analog-to-digital converters (ADCs) in nanometer-CMOS processes.  The authors offer a clear and complete picture of system level challenges and practical design solutions in high-speed Delta-Sigma modulators.  Readers will be enabled to implement ADCs as continuous-time delta-sigma (CT∆Σ) modulators, offering simple resistive inputs, which do not require the use of power-hungry input buffers, as well as offering inherent anti-aliasing, which simplifies system integration. The authors focus on the design of high speed and wide-bandwidth ΔΣMs that make a step in bandwidth range which was previously only possible with Nyquist converters. More specifically, this book describes the stability, power efficiency, and linearity limits of ΔΣMs, aiming at a GHz sampling frequency.   • Provides overview of trends in Wide Bandwidth and High Dynamic Range analog-to-digital converters (ADCs); • Enables the design of a wide band...

  1. Ultra-High-Speed Image Signal Accumulation Sensor

    Directory of Open Access Journals (Sweden)

    Takeharu Goji Etoh

    2010-04-01

    Full Text Available Averaging of accumulated data is a standard technique applied to processing data with low signal-to-noise ratios (SNR, such as image signals captured in ultra-high-speed imaging. The authors propose an architecture layout of an ultra-high-speed image sensor capable of on-chip signal accumulation. The very high frame rate is enabled by employing an image sensor structure with a multi-folded CCD in each pixel, which serves as an in situ image signal storage. The signal accumulation function is achieved by direct connection of the first and the last storage elements of the in situ storage CCD. It has been thought that the multi-folding is achievable only by driving electrodes with complicated and impractical layouts. Simple configurations of the driving electrodes to overcome the difficulty are presented for two-phase and four-phase transfer CCD systems. The in situ storage image sensor with the signal accumulation function is named Image Signal Accumulation Sensor (ISAS.

  2. LES/FMDF of High Speed Spray Combustion

    Science.gov (United States)

    Irannejad, Abolfazl; Jaberi, Farhad

    2013-11-01

    High speed evaporating and combusting sprays are computed with the hybrid two-phase large eddy simulation (LES)/filtered mass density function (FMDF) methodology. In this methodology, the resolved fluid velocity is obtained by solving the filtered form of the compressible Navier-Stokes equations with high-order finite difference schemes. The scalar (temperature and species mass fractions) field is obtained by solving the FMDF transport equation with a Lagrangian stochastic method. The spray is simulated with the Lagrangian droplets together with stochastic breakup and finite rate heat and mass transfer models. The liquid volume fraction is included in the LES/FMDF for denser spray regions. Simulations of high speed evaporating sprays with and without combustion for a range of gas and spray conditions indicate that the two-phase LES/FMDF results are consistent and compare well with the experimental results for global spray variables such as the spray penetration and flame lift-off lengths. The gas velocity and turbulence generated by the spray are found to be very significant in all simulated cases. A broad spectrum of droplet sizes is also found to be generated by the complex and coupled effects of the gas flow turbulence, droplet breakup, evaporation and combustion.

  3. Research on high-speed single photon detector

    Science.gov (United States)

    Wang, Chao; Yang, Hao; Wang, Di; Ma, Haiqiang; Luo, Kaihong; Sun, Zhibin; Zhai, Guangjie

    2010-10-01

    Single-photon detector based on an InGaAs avalanche photodiode is one of hot research on the quantum photon, and is one of the key technologies on quantum communication and quantum image. It is widely used in applications as high sensitive photon spectrum, high speed optic measurement and so on. A suitable delay and comparator with latch function circuit are used to prevent positive and negative transient pulses from influencing the detection of true photon induced avalanches. A dead time modulation feedback control circuit decreases the after-pulse. Especially, ECL difference circuit is the key of high speed single photon detector. In addition, the detector uses the hot tube fan-cooling method. From the performance test, the lowest temperature reaches -62°C, the minimum gate pulse width is 2ns (Full-Width-Half-Max, FWHM) and the dark counter rate is 2.5×10-6 ns-1 with a detection rate of 10MHz when the quantum efficiency is more than 10%.

  4. Laboratory measurements of materials in extreme conditions; The use of high energy radiation sources for high pressure studies

    Energy Technology Data Exchange (ETDEWEB)

    Cauble, R.; Remington, B.A.

    1998-06-01

    High energy lasers can be used to study material conditions that are appropriate fort inertial confinement fusion: that is, materials at high densities, temperatures, and pressures. Pulsed power devices can offer similar opportunities. The National Ignition Facility (NIF) will be a high energy multi-beam laser designed to achieve the thermonuclear ignition of a mm-scale DT-filled target in the laboratory. At the same time, NE will provide the physics community with a unique tool for the study of high energy density matter at states unreachable by any other laboratory technique. Here we describe how these lasers and pulsed power tools can contribute to investigations of high energy density matter in the areas of material properties and equations of state, extend present laboratory shock techniques such as high-speed jets to new regimes, and allow study of extreme conditions found in astrophysical phenomena.

  5. Pitching Speed and Glenohumeral Adaptation in High School Pitchers.

    Science.gov (United States)

    Keller, Robert A; Marshall, Nathan E; Mehran, Nima; Moutzouros, Vasilios

    2015-08-01

    Glenohumeral internal rotational deficit and increased glenohumeral external rotation are common findings in baseball pitchers. To the authors' knowledge, no study has focused on the adaptation of glenohumeral internal rotational deficit and increased glenohumeral external rotation in relation to pitching speed. This study evaluated changes in range of motion in the throwing shoulder in high school pitchers to determine whether changes in internal and external rotation directly correlate with pitch velocity. The shoulders of 22 high school varsity pitchers were evaluated. Standard goniometric technique was used to measure passive external and internal glenohumeral range of motion in both arms. Measurements were evaluated for statistically significant differences in range of motion. Demographic features, including height, weight, and age, were assessed. Fifteen consecutive in-game pitch speeds were recorded, and the fastest pitch was used for evaluation. Pitch speeds were correlated to the player's glenohumeral internal rotational deficit, increased glenohumeral external rotation, and physical demographics. Average age was 16.9 years. Average external rotation of the throwing arm was significantly greater than that of the nonthrowing arm (143.00° vs 130.32°, P=.005). Average internal rotation of the throwing arm was significantly less than that of the nonthrowing arm (49.50° vs 65.90°, P=.006). Both shoulders had similar total arc of motion (throwing shoulder, 192.54; nonthrowing shoulder, 196.23; P=.822). Average maximum velocity was 77.7 mph (maximum, 88 mph; minimum, 66 mph). Maximum pitch velocity did not correlate with changes in glenohumeral internal rotational deficit (P=.683) or increased glenohumeral external rotation (P=.241). There was also no evidence of correlation between pitch velocity and player age, height, weight, or dominant hand. The stress of pitching creates adaptations to the throwing shoulder, even in young athletes. There appears to be

  6. Preliminary identification of buffet problems in high speed civil transport

    Science.gov (United States)

    Ravindra, Krishnaswamy

    1994-01-01

    In the present study, some effort is made to identify whether empennage buffet is a relevant factor in the design and operation of the High Speed Civil Transport (HSCT). Based on some results of the only operational supersonic transport, Concorde and the innumerable studies that exist on the tail buffet of high performance airplanes, CFD analyses on the HSCT as well as low speed wind tunnel tests on models, it appears as though buffet will be a factor that needs attention in the proper design of empennage structure. Utilizing the existing empirical relation between the reduced frequency of the leading edge vortices and the geometric parameters, it is estimated that the characteristic frequencies of the vortices from the wing cranks are in the range of certain fundamental frequencies of the wing-fuselage-empennage structure. Buffet is believed to be critical during take-off, climb, descent and landing. Computational and experimental data available in open literature indicate coherent vortex flow structure in the empennage region at supersonic cruise speeds. This raises further concern on the fatigue life of the empennage structure. Three second generation supersonic transport designs taken from open literature are briefly compared with the 'empennage buffet' in mind. Future research efforts relating to buffet studies on the HSCT are summarized. A bibliography pertaining to the present research, including relevant studies on the first generation supersonic transport is presented. The effect of rounded wing leading edges on the present frequency estimates needs further study. The effect of engine exhaust on the flow field in the empennage region also needs further study.

  7. High Speed Development and Synthesis of Novel Small Molecule Libraries

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Combinatorial chemistry has produced libraries of millions of compounds in the last decade. Screening of those compounds, unfortunately, has not yet yielded as many new drug candidates as initially expected. Among a number of possible reasons, one is that many libraries combinatorial chemistry produced in the early periods are of the nature of linear, flat, and flexible molecules such as peptides and oligonucleotides, which do not have the desired properties to selectively interact with their targets to yield high quality hits and leads. In order to increase the number of quality hits and leads, rigid, structural featurerich and drug-like compound libraries are highly desirable. Design and development of structural features-rich and natural product-like combinatorial libraries, as well as high speed library production using modern solution and solid phase synthesis techniques such as IRORI's Directed Sorting technology, will be discussed.

  8. High Speed Development and Synthesis of Novel Small Molecule Libraries

    Institute of Scientific and Technical Information of China (English)

    XIAO; Xiao-Yi

    2001-01-01

    Combinatorial chemistry has produced libraries of millions of compounds in the last decade. Screening of those compounds, unfortunately, has not yet yielded as many new drug candidates as initially expected. Among a number of possible reasons, one is that many libraries combinatorial chemistry produced in the early periods are of the nature of linear, flat, and flexible molecules such as peptides and oligonucleotides, which do not have the desired properties to selectively interact with their targets to yield high quality hits and leads. In order to increase the number of quality hits and leads, rigid, structural featurerich and drug-like compound libraries are highly desirable. Design and development of structural features-rich and natural product-like combinatorial libraries, as well as high speed library production using modern solution and solid phase synthesis techniques such as IRORI's Directed Sorting technology, will be discussed.  ……

  9. CW-HSTCP: Fair TCP in high-speed networks

    Institute of Scientific and Technical Information of China (English)

    PAN Xue-zeng; SU Fan-jun; L(U) Yong; PING Ling-di

    2006-01-01

    The congestion control mechanisms of the current standard TCP constrain the congestion windows that can be achieved by TCP in high-speed networks, which leads to low link utilization. HSTCP is one solution to solve this problem by modifying the congestion control mechanism to have the characteristics of TCP friendliness in high loss rate environment and high scalability in low loss rate environment. However, experiments revealed that HSTCP has severe RTT unfairness. After analyzing the RTT unfairness in HSTCP with a model, we proposed CW-HSTCP, which added a fair factor to decrease the difference of congestion window caused by different RTT. Fair factor of long RTT flows can cause a sharp window increment that is easy to cause a bursty traffic, so a method called block-pacing was adopted. Simulation results showed that our new proposal could alleviate the RTT unfairness while keeping advantages of HSTCP.

  10. Ultra-high-speed Optical Signal Processing using Silicon Photonics

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Ji, Hua; Jensen, Asger Sellerup

    on silicon photonics. In particular we use nano-engineered silicon waveguides (nanowires) [1] enabling efficient phasematched four-wave mixing (FWM), cross-phase modulation (XPM) or self-phase modulation (SPM) for ultra-high-speed optical signal processing of ultra-high bit rate serial data signals. We show......— In supercomputers, the optical inter-connects are getting closer and closer to the processing cores. Today, a single supercomputer system has as many optical links as the whole worldwide web together, and it is envisaged that future computing chips will contain multiple electronic processor cores...... with a photonic layer on top to interconnect them. For such systems, silicon is an attractive candidate enabling both electronic and photonic control. For some network scenarios, it may be beneficial to use optical on-chip packet switching, and for high data-density environments one may take advantage...

  11. Material Properties of High-Speed Steel Rolls

    Directory of Open Access Journals (Sweden)

    Shaohua Wu

    2017-03-01

    Full Text Available Recently, it has been required to improve the material properties of high-speed steel (HSS rolls, because of the low wear resistance and low mechanical properties. To improve them, several new steels have been proposed, which have high wear resistance as well as excellent mechanical properties, e.g., hardness and tensile properties, where additional elements (V, Cr and W were employed. However, their steels may have still technical issues, as the roll surfaces become roughened during the production process. The reason for this problem is found to be affected by the oxidation of the HSS surface. In this work, we have provided the suggestions to make high wear resistance of the HSS rolls

  12. Tool Failure Analysis in High Speed Milling of Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiuxu; MEYER Kevin; HE Rui; YU Cindy; NI Jun

    2006-01-01

    In high speed milling of titanium alloys the high rate of tool failure is the main reason for its high manufacturing cost. In this study, fractured tools which were used in a titanium alloys 5-axis milling process have been observed both in the macro scale using a PG-1000 light microscope and in the micro scale using a Scanning Electron Microscope (SEM) respectively. These observations indicate that most of these tool fractures are the result of tool chipping. Further analysis of each chipping event has shown that beachmarks emanate from points on the cutting edge. This visual evidence indicates that the cutting edge is failing in fatigue due to cyclical mechanical and/or thermal stresses. Initial analyses explaining some of the outlying conditions for this phenomenon are discussed. Future analysis regarding determining the underlying causes of the fatigue phenomenon is then outlined.

  13. In situ observation and measurement of composites subjected to extremely high temperature

    Science.gov (United States)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  14. Forecasting extreme wave events in moderate and high sea states

    Science.gov (United States)

    Magnusson, Anne Karin; Reistad, Magnar; Bitner-Gregersen, Elzbieta Maria

    2013-04-01

    Empirical studies on measurements have not yet come to conclusive relations between occurrence of rogue waves and - parameters which could be forecasted . Theoretical and tank experiments have demonstrated that high spectral peakedness and low spectral width combined (high Benjamin-Feir instability index, Onorato et al., 2006) give higher probability of rogue wave occurrence. Directional spread seems to reduce the probability of occurrence of rogue waves in these studies. Many years of experience with forecasting and discussions with people working in ocean environment indicate that rogue waves may as well occur in crossing seas. This was also indicated in a study in the Maxwave project (Toffoli et al., 2003) and the EXTREME SEAS project (Toffoli et al., 2011). We have here experimented with some indexes describing both high BFI and crossing seas and run the WAM model for some North Sea storm cases. Wave distributions measured at Ekofisk are analysed in the different cases. References • Onorato, M., Osborne, A., Serio, M., Cavaleri, L., Brandini, C., and Stansberg, C.: Extreme waves, modulational instability and second order theory: wave flume experiments on irregular waves,Europ. J. Mech. B/Fluids, 25, 586-601, 2006. • Toffoli, A., Lefevre, J.M., Monbaliu, J., Savina, H., and Bitner-Gregersen, E., "Freak Waves:Clues for Prediction in Ship Accidents?", Proc. ISOPE'2003 Conf. Hawai, USA, 2003. • Toffoli A., Bitner-Gregersen E. M., Osborne A. R., Serio M. Monbaliu J., Onorato M. (2011) Extreme Waves in Random Crossing Seas: Laboratory Experiments and Numerical Simulations. Geophys. Res. Lett., Vol. 38, L06605, 5 pp. doi: 10.1029/2011.

  15. High-speed visual feedback for realizing high-performance robotic manipulation

    Science.gov (United States)

    Huang, S.; Bergström, N.; Yamakawa, Y.; Senoo, T.; Ishikawa, M.

    2017-02-01

    High-speed vision sensing becomes a driving factor in developing new methods for robotic manipulation. In this paper we present two such methods in order to realize high-performance manipulation. First, we present a dynamic compensation approach which aims to achieve simultaneously fast and accurate positioning under various (from system to external environment) uncertainties. Second, a high-speed motion strategy for manipulating flexible objects is introduced to address the issue of deformation uncertainties. Both methods rely on high-speed visual feedback and are model independent, which we believe is essential to ensure good flexibility in a wide range of applications. The high-speed visual feedback tracks the relative error between the working tool and the target in image coordinates, which implies that there is no need for accurate calibrations of the vision system. Tasks for validating these methods were implemented and experimental results were provided to illustrate the effectiveness of the proposed methods.

  16. High-speed digital fiber optic links for satellite traffic

    Science.gov (United States)

    Daryoush, A. S.; Ackerman, E.; Saedi, R.; Kunath, R. R.; Shalkhauser, K.

    1989-09-01

    Large aperture phased array antennas operating at millimeter wave frequencies are designed for space-based communications and imaging platforms. Array elements are comprised of active T/R modules which are linked to the central processing unit through high-speed fiber-optic networks. The system architecture satisfying system requirements at millimeter wave frequency is T/R level data mixing where data and frequency reference signals are distributed independently before mixing at the T/R modules. This paper demonstrates design procedures of a low loss high-speed fiber-optic link used for transmission of data signals over 600-900 MHz bandwidth inside satellite. The fiber-optic link is characterized for transmission of analog and digital data. A dynamic range of 79 dB/MHz was measured for analog data over the bandwidth. On the other hand, for bursted SMSK satellite traffic at 220 Mbps rates, BER of 2 x 10 to the -7th was measured for E(b)/N(o) of 14.3 dB.

  17. COMPARATIVE STUDY OF NEXT GENERATION HIGH SPEED WIRELESS NETWORK

    Directory of Open Access Journals (Sweden)

    RAHUL MALHOTRA

    2011-06-01

    Full Text Available Advances in mobile communication theory have enabled the development of different wireless access technologies. Alongside the revolutionary progress in wireless access technologies, advances in wireless access devices such as laptops, palmtops, and cell phones and mobile middleware have paved the way for the deliveryof beyond-voice-type services while on the move. This sets the platform for high-speed mobile communications that provide high-speed data and both real and non-real time multimedia to mobile users. Today's wireless world uses several communication infrastructures such as Bluetooth for personal area, IEEE 802.11 for local area,Universal Mobile Telecommunication System (UMTS for wide area, and Satellite networks for global networking other hand, since these wireless networks are complementary to each other, their integration and coordinated operation can provide ubiquitous “always best connection" quality mobile communications to the users. This paper discusses the different architectures of wireless networks and the different factors to be considered while designing a hybrid wireless network. The different factors to be considered for design of ahybrid wireless network and the different networks have been explored in this paper.

  18. High-speed digital video tracking system for generic applications

    Science.gov (United States)

    Walton, James S.; Hallamasek, Karen G.

    2001-04-01

    The value of high-speed imaging for making subjective assessments is widely recognized, but the inability to acquire useful data from image sequences in a timely fashion has severely limited the use of the technology. 4DVideo has created a foundation for a generic instrument that can capture kinematic data from high-speed images. The new system has been designed to acquire (1) two-dimensional trajectories of points; (2) three-dimensional kinematics of structures or linked rigid-bodies; and (3) morphological reconstructions of boundaries. The system has been designed to work with an unlimited number of cameras configured as nodes in a network, with each camera able to acquire images at 1000 frames per second (fps) or better, with a spatial resolution of 512 X 512 or better, and an 8-bit gray scale. However, less demanding configurations are anticipated. The critical technology is contained in the custom hardware that services the cameras. This hardware optimizes the amount of information stored, and maximizes the available bandwidth. The system identifies targets using an algorithm implemented in hardware. When complete, the system software will provide all of the functionality required to capture and process video data from multiple perspectives. Thereafter it will extract, edit and analyze the motions of finite targets and boundaries.

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

    Science.gov (United States)

    Pollard, Victoria J.; Herron, Andrew J.

    2017-01-01

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

  20. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    Directory of Open Access Journals (Sweden)

    Itay Remer

    2016-09-01

    Full Text Available We demonstrate a high-speed stimulated Brillouin scattering (SBS spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (∼25 dB in water samples and ∼15 dB in tissue phantoms. These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  1. High-speed digital phonoscopy images analyzed by Nyquist plots

    Science.gov (United States)

    Yan, Yuling

    2012-02-01

    Vocal-fold vibration is a key dynamic event in voice production, and the vibratory characteristics of the vocal fold correlate closely with voice quality and health condition. Laryngeal imaging provides direct means to observe the vocal fold vibration; in the past, however, available modalities were either too slow or impractical to resolve the actual vocal fold vibrations. This limitation has now been overcome by high-speed digital imaging (HSDI) (or high-speed digital phonoscopy), which records images of the vibrating vocal folds at a rate of 2000 frames per second or higher- fast enough to resolve a specific, sustained phonatory vocal fold vibration. The subsequent image-based functional analysis of voice is essential to better understanding the mechanism underlying voice production, as well as assisting the clinical diagnosis of voice disorders. Our primary objective is to develop a comprehensive analytical platform for voice analysis using the HSDI recordings. So far, we have developed various analytical approaches for the HSDI-based voice analyses. These include Nyquist plots and associated analysese that are used along with FFT and Spectrogram in the analysis of the HSDI data representing normal voice and specific voice pathologies.

  2. Optimisation and simulation of high speed production system

    Directory of Open Access Journals (Sweden)

    J.P.T. Mo

    2008-12-01

    Full Text Available Purpose: This paper describes the project of developing the model of a high speed production system.Design/methodology/approach: High speed production systems involve significant investment and aresensitive to change. It is important to have a plan before changing the facility to minimize risks. To achieve thisgoal, it is necessary to develop a simulation model of the manufacturing process so that the system efficiencyunder different conditions can be evaluated.Findings: The investigation included evaluation of optimal system performance based on machine specificationsand values obtained over a period of observation.Practical implications: These values were used to generate a simulation model and tested under differentconditions. Four of the six recommendations were immediately accepted by the management while the tworemaining recommendations were further investigated to clarify anticipated benefits.Originality/value: This model is simulated in a discrete simulation environment and is based on values obtainedfrom the actual production process. The effect of changing the conditions and compatibility of the system toincreased work and reduced waste can be visualized.

  3. Passive control of rotorcraft high-speed impulsive noise

    Science.gov (United States)

    Szulc, O.; Doerffer, P.; Tejero, F.

    2016-10-01

    A strong, normal shock wave, terminating a local supersonic area located at the tip of a helicopter blade, not only limits the aerodynamic performance, but also constitutes an origin of the High-Speed Impulsive (HSI) noise. The application of a passive control device (a shallow cavity covered by a perforated plate) just beneath the interaction region weakens the compression level, thus reducing the main source of the HSI noise. The numerical investigation based on the URANS approach and Bohning/Doerffer (BD) transpiration law (SPARC code) confirms a large potential of the new method. Two exemplary implementations, adapted to model helicopter rotors tested at NASA Ames facility in transonic conditions: Caradonna-Tung (lifting, transonic hover) and Caradonna-Laub-Tung (non-lifting, high-speed forward flight), demonstrate the possible gains in terms of the reduction of acoustic pressure fluctuations in the near-field of the blade tip. The CFD results are validated against the experimental data obtained for the reference configurations (no control), while the analysis of the passive control arrangement is based on a purely numerical research. The normal shock wave is effectively eliminated by the wall ventilation exerting a positive impact on the generated level of the HSI noise.

  4. High-speed atomic force microscopy: imaging and force spectroscopy.

    Science.gov (United States)

    Eghiaian, Frédéric; Rico, Felix; Colom, Adai; Casuso, Ignacio; Scheuring, Simon

    2014-10-01

    Atomic force microscopy (AFM) is the type of scanning probe microscopy that is probably best adapted for imaging biological samples in physiological conditions with submolecular lateral and vertical resolution. In addition, AFM is a method of choice to study the mechanical unfolding of proteins or for cellular force spectroscopy. In spite of 28 years of successful use in biological sciences, AFM is far from enjoying the same popularity as electron and fluorescence microscopy. The advent of high-speed atomic force microscopy (HS-AFM), about 10 years ago, has provided unprecedented insights into the dynamics of membrane proteins and molecular machines from the single-molecule to the cellular level. HS-AFM imaging at nanometer-resolution and sub-second frame rate may open novel research fields depicting dynamic events at the single bio-molecule level. As such, HS-AFM is complementary to other structural and cellular biology techniques, and hopefully will gain acceptance from researchers from various fields. In this review we describe some of the most recent reports of dynamic bio-molecular imaging by HS-AFM, as well as the advent of high-speed force spectroscopy (HS-FS) for single protein unfolding.

  5. A High Speed Autofocusing System for Micro System Applications

    Institute of Scientific and Technical Information of China (English)

    Phuchong Sripolsaen; Pradit Mittrapiyanuruk; Pakorn Keawtrakulpong

    2016-01-01

    In this paper, we present a high speed autofocus system for micro system applications and design a look-up-table based autofocusing algorithm for applications when a target object is always visible, e.g., manufacturing parts with alignment fiducials. We perform an evaluation of 24 focus measures to verify that which focus measure is the best for the look-up-table based method. From the evaluation, we find that the Chebyshev moments-based focus measure (CHEB) is the most suitable. Furthermore, we also develop a look-up-table based autofocus system that uses CHEB as the focus measure. In training phase, we offline construct a table from training images of an object that are captured at several lens distances. Each entry of table consists of focus measure computed from image and lens distance. In working phase, given an input image, the algorithm first computes the focus measure and then finds the best match focus measure from the table and looks up the corresponding lens position for moving it into the in-focus position. Our algorithm can perform autofocusing within only 2 steps of lens moving. The experiment shows that the system can perform high speed autofocusing of micro objects.

  6. Analysis of high-speed digital phonoscopy pediatric images

    Science.gov (United States)

    Unnikrishnan, Harikrishnan; Donohue, Kevin D.; Patel, Rita R.

    2012-02-01

    The quantitative characterization of vocal fold (VF) motion can greatly enhance the diagnosis and treatment of speech pathologies. The recent availability of high-speed systems has created new opportunities to understand VF dynamics. This paper presents quantitative methods for analyzing VF dynamics with high-speed digital phonoscopy, with a focus on expected VF changes during childhood. A robust method for automatic VF edge tracking during phonation is introduced and evaluated against 4 expert human observers. Results from 100 test frames show a subpixel difference between the VF edges selected by algorithm and expert observers. Waveforms created from the VF edge displacement are used to created motion features with limited sensitivity to variations of camera resolution on the imaging plane. New features are introduced based on acceleration ratios of critical points over each phonation cycle, which have the potential for studying issues related to impact stress. A novel denoising and hybrid interpolation/extrapolation scheme is also introduced to reduce the impact of quantization errors and large sampling intervals relative to the phonation cycle. Features extracted from groups of 4 adults and 5 children show large differences for features related to asymmetry between the right and left fold and consistent differences for impact acceleration ratio.

  7. Influence of “J”-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion

    Directory of Open Access Journals (Sweden)

    Runxiao Wang

    2016-01-01

    Full Text Available Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of “J”-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with “J”-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with “J”-curve spring stiffness reveals that (1 both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2 at fast running speed from 25 to 40/92 m s−1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with “J”-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

  8. Short pulse generation and high speed communication system

    Science.gov (United States)

    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.

  9. Advanced Ultra-High Speed Motor for Drilling

    Energy Technology Data Exchange (ETDEWEB)

    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

  10. 14 CFR 23.253 - High speed characteristics.

    Science.gov (United States)

    2010-01-01

    ... conditions and characteristics likely to cause inadvertent speed increases (including upsets in pitch and... about any axis at any speed up to the maximum speed shown under § 23.251. Any reversal of elevator control force or tendency of the airplane to pitch, roll, or yaw must be mild and readily controllable...

  11. Ultra High-Speed CMOS Circuits Beyond 100 GHz

    CERN Document Server

    Gharavi, Sam

    2012-01-01

    The book covers the CMOS-based millimeter wave circuits and devices and presents methods and design techniques to use CMOS technology for circuits operating beyond 100 GHz.� Coverage includes a detailed description of both active and passive devices, including modeling techniques and performance optimization. Various mm-wave circuit blocks are discussed, emphasizing their design distinctions from low-frequency design methodologies. This book also covers a device-oriented circuit design technique that is essential for ultra high speed circuits and gives some examples of device/circuit co-design that can be used for mm-wave technology. Offers a detailed description of high frequency device modeling from a circuit designer perspective; Presents a set of techniques for optimizing the performance of CMOS for mm-wave technology, including noise and low noise design for mm-wave; Introduces circuit/device co-design techniques. �

  12. OPTIMA A Photon Counting High-Speed Photometer

    CERN Document Server

    Straubmeier, C; Schrey, F

    2001-01-01

    OPTIMA is a small, versatile high-speed photometer which is primarily intended for time resolved observations of young high energy pulsars at optical wavelengths. The detector system consists of eight fiber fed photon counters based on avalanche photodiodes, a GPS timing receiver, an integrating CCD camera to ensure the correct pointing of the telescope and a computerized control unit. Since January 1999 OPTIMA proves its scientific potential by measuring a very detailed lightcurve of the Crab Pulsar as well as by observing cataclysmic variable stars on very short timescales. In this article we describe the design of the detector system focussing on the photon counting units and the software control which correlates the detected photons with the GPS timing signal.

  13. Errors in particle tracking velocimetry with high-speed cameras

    CERN Document Server

    Feng, Yan; Liu, Bin

    2011-01-01

    Velocity errors in particle tracking velocimetry (PTV) are studied. When using high-speed video cameras, the velocity error may increase at a high camera frame rate. This increase in velocity error is due to particle-position uncertainty, which is one of two sources of velocity errors studied here. The other source of error is particle acceleration, which has the opposite trend of diminishing at higher frame rates. Both kinds of errors can propagate into quantities calculated from velocity, such as the kinetic temperature of particles or correlation functions. As demonstrated in a dusty plasma experiment, the kinetic temperature of particles has no unique value when measured using PTV, but depends on the sampling time interval or frame rate. It is also shown that an artifact appears in an autocorrelation function computed from particle positions and velocities, and it becomes more severe when a small sampling-time interval is used. Schemes to reduce these errors are demonstrated.

  14. High-Speed, Three Dimensional Object Composition Mapping Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, M Y

    2001-02-14

    This document overviews an entirely new approach to determining the composition--the chemical-elemental, isotopic and molecular make-up--of complex, highly structured objects, moreover with microscopic spatial resolution in all 3 dimensions. The front cover depicts the new type of pulsed laser system at the heart of this novel technology under adjustment by Alexis Wynne, and schematically indicates two of its early uses: swiftly analyzing the 3-D composition governed structure of a transistor circuit with both optical and mass-spectrometric detectors, and of fossilized dinosaur and turtle bones high-speed probed by optical detection means. Studying the composition-cued 3-D micro-structures of advanced composite materials and the microscopic scale composition-texture of biological tissues are two near-term examples of the rich spectrum of novel applications enabled by this field-opening analytic tool-set.

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

    Science.gov (United States)

    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. A novel optical burst switching architecture for high speed networks

    Institute of Scientific and Technical Information of China (English)

    Amit Kumar Garg; R. S. Kaler

    2008-01-01

    A novel optical burst switching (OBS) high speed network architecture has been proposed. To verify its feasibility and evaluate its performance, just-enough-time (JET) signaling has been considered as a high performance protocol. In the proposed architecture, to avoid burst losses, firstly, a short-priorconfirrnation-packet (SPCP) is sent over the control channel that simulates the events that the actual packet will experience. Once SPCP detects a drop at any of the intermediate nodes, the actual packet is not sent but the process repeats. In order to increase network utilization, cost effectiveness and to overcome some limitations of conventional OBS, inherent codes (e.g., orthogonal optical codes (OOC)),which are codified only in intensity, has been used. Through simulations, it shows that a decrease in burst loss probability, cost effectiveness and a gain in processing time are obtained when optical label processing is used as compared with electronic processing.

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

    Science.gov (United States)

    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.

  18. Optimization and Performance Analysis of High Speed Mobile Access Networks

    CERN Document Server

    Weerawardane, Thushara

    2012-01-01

    The design and development of cost-effective mobile broadband wireless access networks is a key challenge for many mobile network operators. The over-dimensioning or under-dimensioning of an access network results in both additional costs and customer dissatisfaction.   Thushara Weerawardane introduces new transport technologies and features for High Speed Packet Access (HSPA) and Long-Term Evolution (LTE) networks. Using advanced scientific methods, he proposes new adaptive flow control and enhanced congestion control algorithms, then defends them with highly-developed analytical models derived from Markov chains. For faster analysis, compared to long-lasting detailed simulations, these models provide optimum network performance and ensure reliable quality standards for end users during transport network congestion. Further, the author investigates and analyzes LTE transport network performance by introducing novel traffic differentiation models and buffer management techniques during intra-LTE handovers.

  19. FPGA based High Speed Data Acquisition System for High Energy Physics Application

    CERN Document Server

    Mandal, Swagata; Chakrabarti, Amlan; Chattopadhyay, Subhasis

    2015-01-01

    In high energy physics experiments (HEP), high speed and fault resilient data communication is needed between detectors/sensors and the host PC. Transient faults can occur in the communication hardware due to various external effects like presence of charged particles, noise in the environment or radiation effects in HEP experiments and that leads to single/multiple bit error. In order to keep the communication system functional in such a radiation environment where direct intervention of human is not possible, a high speed data acquisition (DAQ) architecture is necessary which supports error recovery. This design presents an efficient implementation of field programmable gate array (FPGA) based high speed DAQ system with optical communication link supported by multi-bit error correcting model. The design has been implemented on Xilinx Kintex-7 board and is tested for board to board communication as well as for PC communication using PCI (Peripheral Component Interconnect express). Data communication speed up...

  20. Measurement of Metal Cutting Forces at High Speeds

    Science.gov (United States)

    Princehouse, David W.

    1996-03-01

    Proposed numerically-controlled milling machines will cut aluminum alloys with cutter tip speeds of up to 130 m/s (300 MPH). There are a variety of challenging technical problems to be solved--high power density motors, inverters, cutter/machine dynamics, servo control systems--and compelling reasons to do so. We measured time-varying cutting forces at these tip speeds with a 25.4-cm (10-in) diameter cutter turning at rates up to 167 Hz (10,000 RPM.) We took special care to measure and compensate for the dynamic response of the force transducer (a three-axis quartz-crystal milling dynamometer), extending the useful bandwidth of the measurements well into the mechanical resonances of the dynamometer. We instrumented a production milling machine on the factory floor and processed megabytes of data, obtaining results minutes after a cut was made. This case study shows how a physicist's background in mechanics, instrumentation, signal processing, and computing hardware and software can help advance the state of the art in aerospace manufacturing.

  1. Design of an Ultimate High Speed Electrical Drive System

    Directory of Open Access Journals (Sweden)

    C. Vishnu Kiran

    2014-05-01

    Full Text Available New emerging applications in the areas of portable power generation, small turbocompressors and spindles require the development of ultrahigh-speed, low power electrical drives. A 500 000 r/min, 100 W electrical drive system is presented. Because of the ultrahigh-speed requirements, standard machine design and power electronic topology choices no longer apply and the complete drive system has to be considered. A permanent magnet machine with a slotless litz-wire winding is used, which results in a low motor inductance and a high fundamental machine frequency. Three different combinations of power electronic topologies and commutation strategies have been experimentally investigated. A voltage source inverter with block commutation and an additional dc–dc converter is selected as the most optimal choice for the power electronics interface as it results in the lowest volume of the entire drive system due to lower switching losses, no heat sink cooling required, a small number of semiconductor devices, and relatively simple control implementation in a low cost digitalsignal processor.

  2. Numerical Simulation of Oil Jet Lubrication for High Speed Gears

    Directory of Open Access Journals (Sweden)

    Tommaso Fondelli

    2015-01-01

    Full Text Available The Geared Turbofan technology is one of the most promising engine configurations to significantly reduce the specific fuel consumption. In this architecture, a power epicyclical gearbox is interposed between the fan and the low pressure spool. Thanks to the gearbox, fan and low pressure spool can turn at different speed, leading to higher engine bypass ratio. Therefore the gearbox efficiency becomes a key parameter for such technology. Further improvement of efficiency can be achieved developing a physical understanding of fluid dynamic losses within the transmission system. These losses are mainly related to viscous effects and they are directly connected to the lubrication method. In this work, the oil injection losses have been studied by means of CFD simulations. A numerical study of a single oil jet impinging on a single high speed gear has been carried out using the VOF method. The aim of this analysis is to evaluate the resistant torque due to the oil jet lubrication, correlating the torque data with the oil-gear interaction phases. URANS calculations have been performed using an adaptive meshing approach, as a way of significantly reducing the simulation costs. A global sensitivity analysis of adopted models has been carried out and a numerical setup has been defined.

  3. Application of DSP Blackfin in data acquisition of high speed

    Science.gov (United States)

    Tang, Chao

    2015-12-01

    In the traditional digital collection, the use of FIFO and MCU is usually used. Traditional data acquisition systems are expensive and slow, When the input is a fast changing signal, the output will have a large distortion, which makes the whole system performance degradation, and not suitable for large amounts of data. In this paper, a new method of high speed data acquisition based on Blackfin DSP is presented, The analog signal is processed by the signal processing circuit, so that the amplitude of the signal is limited to the input range of the A/D converter. The whole collection system is determined by the data acquisition and control circuit. In order to further improve the speed of data transmission, DSP Blackfin uses advanced DMA technology. In the algorithm, the system is mainly used in the same sampling points for the average value of the method. Experimental results show, Using the traditional system, it will lose a lot of details, the destruction of the integrity of the signal. Using this system can well reconstruct the analog signal input, Especially in the large amount of data, it shows the incomparable advantages.

  4. High Speed Computational Ghost Imaging via Spatial Sweeping

    Science.gov (United States)

    Wang, Yuwang; Liu, Yang; Suo, Jinli; Situ, Guohai; Qiao, Chang; Dai, Qionghai

    2017-01-01

    Computational ghost imaging (CGI) achieves single-pixel imaging by using a Spatial Light Modulator (SLM) to generate structured illuminations for spatially resolved information encoding. The imaging speed of CGI is limited by the modulation frequency of available SLMs, and sets back its practical applications. This paper proposes to bypass this limitation by trading off SLM’s redundant spatial resolution for multiplication of the modulation frequency. Specifically, a pair of galvanic mirrors sweeping across the high resolution SLM multiply the modulation frequency within the spatial resolution gap between SLM and the final reconstruction. A proof-of-principle setup with two middle end galvanic mirrors achieves ghost imaging as fast as 42 Hz at 80 × 80-pixel resolution, 5 times faster than state-of-the-arts, and holds potential for one magnitude further multiplication by hardware upgrading. Our approach brings a significant improvement in the imaging speed of ghost imaging and pushes ghost imaging towards practical applications. PMID:28358010

  5. High-speed simulation of transients in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-01-01

    A combination of advanced modeling techniques and modern, special-purpose peripheral minicomputer technology is presented which affords realistic predictions of plant transient and severe off-normal events in LWR power plants through on-line simulations at a speed ten times greater than actual process speeds. Results are shown for a BWR plant simulation. Results are shown to demonstrate computing capacity, accuracy, and speed. Simulation speeds have been achieved which are 110 times larger than those of a CDC-7600 mainframe computer or ten times greater than real-time speed.

  6. 36 CFR 1192.175 - High-speed rail cars, monorails and systems.

    Science.gov (United States)

    2010-07-01

    ...) All cars for high-speed rail systems, including but not limited to those using “maglev” or high speed...., not used by freight trains) or guideway, in which stations are constructed in accordance with...

  7. High-speed particle image velocimetry near surfaces.

    Science.gov (United States)

    Lu, Louise; Sick, Volker

    2013-06-24

    Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The complex nature of these flows may be studied using particle image velocimetry (PIV), a laser-based imaging technique for optically accessible flows. Though many forms of PIV exist that extend the technique beyond the original planar two-component velocity measurement capabilities, the basic PIV system consists of a light source (laser), a camera, tracer particles, and analysis algorithms. The imaging and recording parameters, the light source, and the algorithms are adjusted to optimize the recording for the flow of interest and obtain valid velocity data. Common PIV investigations measure two-component velocities in a plane at a few frames per second. However, recent developments in instrumentation have facilitated high-frame rate (>1 kHz) measurements capable of resolving transient flows with high temporal resolution. Therefore, high-frame rate measurements have enabled investigations on the evolution of the structure and dynamics of highly transient flows. These investigations play a critical role in understanding the fundamental physics of complex flows. A detailed description for performing high-resolution, high-speed planar PIV to study a transient flow near the surface of a flat plate is presented here. Details for adjusting the parameter constraints such as image and recording properties, the laser sheet properties, and processing algorithms to adapt PIV for any flow of interest are included.

  8. The SPEED Project: SPEEDing up Research and Development towards High-contrast Imaging Instruments for the E-ELT

    Science.gov (United States)

    Martinez, P.; Preis, O.; Gouvret, C.; Dejongue, J.; Daban, J.-B.; Spang, A.; Martinache, F.; Beaulieu, M.; Janin-Potiron, P.; Abe, L.; Fantei-Cujolle, Y.; Ottogalli, S.; Mattei, D.; Carbillet, M.

    2015-03-01

    An overview is presented of the Segmented Pupil Experiment for Exoplanet Detection (SPEED) testbench. This is an advanced facility in development at the Lagrange Laboratory that will address several of the most critical issues affecting high-contrast imaging for the next generation of optical/near-infrared telescopes. The SPEED testbed can be used to investigate practical solutions for broadband coronography on asymmetric, unfriendly apertures, enabling algorithmic or optical approaches to be developed to minimise segment effects and pupil discontinuity.

  9. High-speed cinematography of gas-metal atomization

    Energy Technology Data Exchange (ETDEWEB)

    Ting, Jason [ALCOA Specialty Metals Division, 100 Technical Drive, Alcoa Center, PA 15069 (United States)]. E-mail: jason.ting@alcoa.com; Connor, Jeffery [Material Science Engineering Department, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Ridder, Stephen [Metallurgical Processing Group, NIST, 100 Bureau Dr. Stop 8556, Gaithersburg, MD 20899 (United States)

    2005-01-15

    A high-speed cinematographic footage of a 304L stainless steel gas atomization, recorded at the National Institute of Standard and Technology (NIST), was analyzed using a discrete Fourier transform (DFT) algorithm. The analysis showed the gas atomization process possesses two prominent frequency ranges of melt oscillation (pulsation). A low-frequency oscillation in the melt flow occurring between 5.41 and 123 Hz, with a dominant frequency at 9.93 Hz, was seen in the recirculation zone adjacent to the melt orifice. A high-frequency melt oscillation range was observed above 123 Hz, and was more prominent one melt-tip-diameter downstream in the melt atomization image than upstream near the melt tip. This high-frequency range may reflect the melt atomization frequency used to produce finely atomized powder. This range also included a prominent high frequency at 1273 Hz, which dominated in the image further away downstream from the melt tip. This discrete high-frequency oscillation is most probably caused by the aeroacoustic ''screech'' phenomenon, intrasound (<20 kHz), a result of the atomizing gas jets undergoing flow resonance. It is hypothesized that this discrete intrinsic aeroacoustic tone may enhance melt breakup in the atomization process with evidence of this fact in the melt images.

  10. Flow structure around high-speed train in open air

    Institute of Scientific and Technical Information of China (English)

    田红旗; 黄莎; 杨明智

    2015-01-01

    According to the analysis of the turbulent intensity level around the high-speed train, the maximum turbulent intensity ranges from 0.2 to 0.5 which belongs to high turbulent flow. The flow field distribution law was studied and eight types of flow regions were proposed. They are high pressure with air stagnant region, pressure decreasing with air accelerating region, low pressure with high air flow velocity region I, turbulent region, steady flow region, low pressure with high air flow velocity region II, pressure increasing with air decelerating region and wake region. The analysis of the vortex structure around the train shows that the vortex is mainly induced by structures with complex mutation and large curvature change. The head and rear of train, the underbody structure, the carriage connection section and the wake region are the main vortex generating sources while the train body with even cross-section has rare vortexes. The wake structure development law studied lays foundation for the train drag reduction.

  11. SONIC SPEED AND SHOCK WAVE IN HIGH VELOCITY AERATED FLOWS FROM HIGH HEAD DISCHARGE STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    Dong Zhi-yong

    2003-01-01

    The compressible characteristics in aerated flows at the high velocity of about 50m/s were analyzed. Based on the theory of compressible the relations between the sonic speed and shock wave in high-velocity aerated flow were theoretically deduced. And comparisons with measured data were made. The theoretical and experimental results show the sonic speed in aerated flow is merely of the order of several-dozen meters per second, and its minimum value is only 20m/s, which is far much less than that in water or air alone. So high subsonic flow, supersonic flow and transonic flow as well as compression wave, shock wave and expansion wave similarly to aerodnamics may be produced in high velocity aerated flow at the speed of the order of 50m/s. Hence the influences of these compressible characteristics on high head discharge structures can not be neglected, especially on super high dams over 200m high.

  12. Research Progress of Key Technology of High-Speed and High Precision Motorized Spindles

    Institute of Scientific and Technical Information of China (English)

    XIONG Wan-li; MI Hai-qing; HUANG Hon-gwu

    2005-01-01

    High speed machining and high precision machining are two tendencies of the manufacturing technology worldwide. The motorized spindle is the core component of the machine tools for achieving the high speed and high precise machining, which affects the general development level of the machine tools to a great extent. Progress of the key techniques is reviewed in this paper, in which the high speed and high precision spindle bearings, the dynamical and thermal characteristics of spindles, the design technique of the high frequency motors and the drivers, the anti-electromagnetic damage technique of the motors, and the machining and assembling technique are involved. Finally, tha development tendencies of the motorized spindles are presented.

  13. Characterization of deflagrating munitions by rotating prism high speed photography

    Science.gov (United States)

    Kinsey, Trevor J.; Bussell, Tim J.; Chick, Michael C.

    1992-08-01

    We report on the use of a rotating prism high speed camera for determining the characteristics of a munition undergoing rapid deflagration in field experiments. The technique has been applied to study the controlled deflagration of Composition B filled 105 mm shell and 81 mm mortar bombs as representative thick and thin cased munitions respectively; however the report is mostly illustrated with results from the study on 105 mm shell. The deflagration event has been characterized in terms of case expansion rate, initial fragment velocity, time to case burst, time to reaction from the nose end and the deflagration rate of the filling. Products escaping from the fracturing case eventually obscured the image which limited the extent of the measurement.

  14. High-speed polysilicon CMOS photodetector for telecom and datacom

    Science.gov (United States)

    Atabaki, Amir H.; Meng, Huaiyu; Alloatti, Luca; Mehta, Karan K.; Ram, Rajeev J.

    2016-09-01

    Absorption by mid-bandgap states in polysilicon or heavily implanted silicon has been previously utilized to implement guided-wave infrared photodetectors in CMOS compatible photonic platforms. Here, we demonstrate a resonant guided-wave photodetector based on the polysilicon layer that is used for the transistor gate in a microelectronic SOI CMOS process without any change to the foundry process flow ("zero-change" CMOS). Through a combination of doping mask layers, a lateral pn junction diode in the polysilicon is demonstrated with a strong electric field to enable efficient photo-carrier extraction and high-speed operation. This photodetector has a responsivity of more than 0.14 A/W from 1300 to 1600 nm, a 10 GHz bandwidth, and 80 nA dark current at 15 V reverse bias.

  15. High-speed detection of DNA translocation in nanopipettes.

    Science.gov (United States)

    Fraccari, Raquel L; Ciccarella, Pietro; Bahrami, Azadeh; Carminati, Marco; Ferrari, Giorgio; Albrecht, Tim

    2016-04-14

    We present a high-speed electrical detection scheme based on a custom-designed CMOS amplifier which allows the analysis of DNA translocation in glass nanopipettes on a microsecond timescale. Translocation of different DNA lengths in KCl electrolyte provides a scaling factor of the DNA translocation time equal to p = 1.22, which is different from values observed previously with nanopipettes in LiCl electrolyte or with nanopores. Based on a theoretical model involving electrophoresis, hydrodynamics and surface friction, we show that the experimentally observed range of p-values may be the result of, or at least be affected by DNA adsorption and friction between the DNA and the substrate surface.

  16. High-speed analog fiber optic links for satellite communication

    Science.gov (United States)

    Daryoush, A. S.; Herczfeld, P. R.; Kunath, R. R.

    1988-01-01

    Large-aperture phased array antennas operating at millimeter wave frequencies are designed for space-based communications and imaging. Array elements are comprised of active transmit/receive (T/R) modules which are linked to the central processing unit through a high-speed fiberoptic network. This paper demonstrates optical control of active modules for satellite communication at 24 GHz. An approach called T/R level data mixing, which utilizes fiberoptic transmission of a data signal to individual T/R modules to be upconverted by an optically synchronized local oscillator, is demonstrated at 24 GHz. A free-running HEMT oscillator, used as local oscillator at 24 GHz, is synchronized using indirect subharmonic optical injection locking over a locking range of 14 MHz. Results of data link performance over 500-1000 MHz is also reported in terms of gain-bandwidth, linearity and third-order intercept, sensitivity, and dynamic range.

  17. Scratch behavior of high speed steels for hot rolls

    Institute of Scientific and Technical Information of China (English)

    Li Zhou; Dale Sun; Changsheng Liu; Chunguang Li; Lisong Yao

    2008-01-01

    The scratch behaviors of two high speed steels (HSS) for hot rolls were studied by a Micro-combi Tester, and the emphasis was placed on researching the relations between the microstructure and the scratch resistance property of different HSS. The experimental results indicate that during the scratch process, the carbides are embedded into the matrix, the penetration depth of different HSS is closely related with the matrix hardness, i.e., the higher the matrix hardness, the better the scratch resistance property; and in the matrix, the fine, dispersive carbides are beneficial to form steady friction between the indenter and the scratched materials, but the coarser carbides are easier to fall into pieces.

  18. Classically entangled optical beams for high-speed kinematic sensing

    CERN Document Server

    Berg-Johansen, Stefan; Stiller, Birgit; Banzer, Peter; Ornigotti, Marco; Giacobino, Elisabeth; Leuchs, Gerd; Aiello, Andrea; Marquardt, Christoph

    2015-01-01

    Tracking the kinematics of fast-moving objects is an important diagnostic tool for science and engineering. Existing optical methods include high-speed CCD/CMOS imaging, streak cameras, lidar, serial time-encoded imaging and sequentially timed all-optical mapping. Here, we demonstrate an entirely new approach to positional and directional sensing based on the concept of classical entanglement in vector beams of light. The measurement principle relies on the intrinsic correlations existing in such beams between transverse spatial modes and polarization. The latter can be determined from intensity measurements with only a few fast photodiodes, greatly outperforming the bandwidth of current CCD/CMOS devices. In this way, our setup enables two-dimensional real-time sensing with temporal resolution in the GHz range. We expect the concept to open up new directions in photonics-based metrology and sensing.

  19. Fracture characteristics of bulk metallic glass under high speed impact

    Institute of Scientific and Technical Information of China (English)

    Sun Bao-Ru; Zhan Zai-Ji; Liang Bo; Zhang Rui-Jun; Wang Wen-Kui

    2012-01-01

    High speed impact experiments of rectangular plate-shaped Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass(BMG)were performed using a two-stage light gas gun.Under spherical shock waves with impact velocities ranging from 0.503 km/s to 4.917 km/s,obvious traces of laminated spallation at the back(free)surface and melting(liquid droplets)at the impact point were observed.The angles about 0°,17°,36°,and 90° to the shocking direction were shown in the internal samples because of the interaction between the compressive shock waves and the rarefaction waves.The compressive normal stress was found to induce the consequent temperature rise in the core of the shear band.

  20. AGAINTS AND FOR THE HIGH SPEED TRAINS’ MULTIMPLICATION

    Directory of Open Access Journals (Sweden)

    Benea Ciprian

    2008-05-01

    Full Text Available In this exposure we intend to make visible the situation in which global warming is given by road and air transport, how could be revitalized railways, and how high speed trains could become a preferred mode of transport. But there is manifesting an opposition to railway development, nurtured by different interests, ranking from governments themselves, to oil importing countries, oil exporting countries, oil companies with their colligate partners situated along the oil distribution chain. But, there could be identified some voices which could create themselves the possibility to speak lauder in order to promote railway transportation. The greens, NGOs, the epistemic communities, for example, could unite their force to make something in order to provide the framework for rail transportation’s development, and for road and air transport reduction, for the benefit of while humankind.

  1. System and Method for High-Speed Data Recording

    Science.gov (United States)

    Taveniku, Mikael B. (Inventor)

    2017-01-01

    A system and method for high speed data recording includes a control computer and a disk pack unit. The disk pack is provided within a shell that provides handling and protection for the disk packs. The disk pack unit provides cooling of the disks and connection for power and disk signaling. A standard connection is provided between the control computer and the disk pack unit. The disk pack units are self sufficient and able to connect to any computer. Multiple disk packs are connected simultaneously to the system, so that one disk pack can be active while one or more disk packs are inactive. To control for power surges, the power to each disk pack is controlled programmatically for the group of disks in a disk pack.

  2. High speed diesel consumption and economic growth in India

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sajal [Management Development Institute (MDI), Gurgaon 122001 (India)

    2010-04-15

    This study probes the long-term equilibrium relationship among High Speed Diesel (HSD) consumption, real GDP and price of HSD in India using autoregressive distributed lag (ARDL) bounds testing approach of cointegration for the time span 1972-1973 to 2005-2006. Empirical results reveal that the series are cointegrated and long term income elasticity for HSD demand in India is 1.27 while that for short-run is 0.46. Both long-run and short-run price elasticities are found to be statistically insignificant. The study also establishes a short-run bi-directional causality between economic growth and HSD consumption and the existence of a long-run unidirectional causality running from economic growth to HSD consumption. Finally, a set of policy prescriptions have been suggested to reduce the consumption of HSD, which should have no adverse impact on economy in the long-run. (author)

  3. Flow Characterization of a Piezo-Electric High Speed Valve

    Directory of Open Access Journals (Sweden)

    T. Takiya

    2012-03-01

    Full Text Available Injecting a gas into fusion reactors or semiconductor manufacturing systems, one has to quickly control the flow rate by a piezoelectric valve. In order to construct a gas injection system with high speed valves in the future, performance tests have been conducted on a commercial piezoelectric valve. An orifice flowmeter for measuring time average flowrate and a hot wire anemometer for instantaneous flowrate were manufactured. The total flow coefficient of the orifice flowmeter was obtained experimentally under a low pressure of a 10-2 Pa and a low flowrate of a few mg/s, although they are smaller than the values specified by Japanese Industrial Standards. It is found that the hot wire anemometer installed downstream in the vicinity of the valve is suitable for detecting the change in flowrate with the response time of less than 1 ms.

  4. DAC for High Speed and Low Power Applications Using Abacus

    Directory of Open Access Journals (Sweden)

    Shankarayya G. Kambalimath

    2014-02-01

    Full Text Available This paper proposes a Chinese Abacus Digital-to-Ana log Converter (DAC for high speed and low power applications like audio and video applica tions. This circuit of DAC uses resister strings to get a good analog output. The designed D AC uses the algorithm of abacus. Instead of using binary code, here we use abacus code to contr ol the switches. So the complexity and the area will be reduced automatically. The 8-bit D AC is comprised of 12 resistors and 24 NMOS switches. The 8-bit Abacus resistor DAC requires 12 resistors and 24 switches. The 8-bit resistor-string DAC requires 255 resistors and 256 switches. The most important advantages are that the numbers of both resistors and switches are all reduced effectively. The simulation environment uses 1 μ m process technology

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

    Science.gov (United States)

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

    2005-06-27

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

  6. Titanium Alloys and Processing for High Speed Aircraft

    Science.gov (United States)

    Brewer, William D.; Bird, R. Keith; Wallace, Terryl A.

    1996-01-01

    Commercially available titanium alloys as well as emerging titanium alloys with limited or no production experience are being considered for a variety of applications to high speed commercial aircraft structures. A number of government and industry programs are underway to improve the performance of promising alloys by chemistry and/or processing modifications and to identify appropriate alloys and processes for specific aircraft structural applications. This paper discusses some of the results on the effects of heat treatment, service temperatures from - 54 C to +177 C, and selected processing on the mechanical properties of several candidate beta and alpha-beta titanium alloys. Included are beta alloys Timetal 21S, LCB, Beta C, Beta CEZ, and Ti-10-2-3 and alpha-beta alloys Ti-62222, Ti-6242S, Timetal 550, Ti-62S, SP-700, and Corona-X. The emphasis is on properties of rolled sheet product form and on the superplastic properties and processing of the materials.

  7. Capacity of High-Speed Powerline Communication in Vehicles

    Directory of Open Access Journals (Sweden)

    Deny Hamdani

    2010-10-01

    Full Text Available Powerline Communication (PLC Systems intents to use the mains network in vehicles for high-speed data transmission. Carrier frequencies in the range of MHz are required to establish data rates of some megabits per second. In this paper, typical reference channels extracted from channel measurements are presented and computation results of their capacities according to Shannon's theorem are presented. Furthermore, the effect of limitations of frequency range and power spectral density of transmitted signal on achievable capacity is investigated. This paper outlines an assessment for theoretical channel capacity and achievable data rates of vehicular PLC transmission schemes. Finally, EMC (Electromagnetics Compatibility constraint according to CISPR 25 (Comite International Special des Perturbations Radioelectrique - The International Special Committee on Radio Interference is deeply considered.

  8. High-Speed Jet Formation after Solid Object Impact

    Science.gov (United States)

    Gekle, Stephan; Gordillo, José Manuel; van der Meer, Devaraj; Lohse, Detlef

    2009-01-01

    A circular disc hitting a water surface creates an impact crater which after collapse leads to a vigorous jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in a single point halfway down the cavity. Two fast sharp-pointed jets are observed shooting up- and downwards from the closure location, which by then has turned into a stagnation point surrounded by a locally hyperbolic flow pattern. This flow, however, is not the mechanism feeding the jets. Using high-speed imaging and numerical simulations we show that jetting is fed by the local flow around the base of the jet, which is forced by the colliding cavity walls. We show how the well-known theory of a collapsing void (using a line of sinks on the symmetry axis) can be continued beyond pinch-off to obtain a new and quantitative model for jet formation which agrees well with numerical and experimental data.

  9. Dual-camera system for high-speed imaging in particle image velocimetry

    CERN Document Server

    Hashimoto, K; Hara, T; Onogi, S; Mouri, H

    2012-01-01

    Particle image velocimetry is an important technique in experimental fluid mechanics, for which it has been essential to use a specialized high-speed camera. However, the high speed is at the expense of other performances of the camera, i.e., sensitivity and image resolution. Here, we demonstrate that the high-speed imaging is also possible with a pair of still cameras.

  10. High-Speed Edge-Detecting Line Scan Smart Camera

    Science.gov (United States)

    Prokop, Norman F.

    2012-01-01

    A high-speed edge-detecting line scan smart camera was developed. The camera is designed to operate as a component in a NASA Glenn Research Center developed inlet shock detection system. The inlet shock is detected by projecting a laser sheet through the airflow. The shock within the airflow is the densest part and refracts the laser sheet the most in its vicinity, leaving a dark spot or shadowgraph. These spots show up as a dip or negative peak within the pixel intensity profile of an image of the projected laser sheet. The smart camera acquires and processes in real-time the linear image containing the shock shadowgraph and outputting the shock location. Previously a high-speed camera and personal computer would perform the image capture and processing to determine the shock location. This innovation consists of a linear image sensor, analog signal processing circuit, and a digital circuit that provides a numerical digital output of the shock or negative edge location. The smart camera is capable of capturing and processing linear images at over 1,000 frames per second. The edges are identified as numeric pixel values within the linear array of pixels, and the edge location information can be sent out from the circuit in a variety of ways, such as by using a microcontroller and onboard or external digital interface to include serial data such as RS-232/485, USB, Ethernet, or CAN BUS; parallel digital data; or an analog signal. The smart camera system can be integrated into a small package with a relatively small number of parts, reducing size and increasing reliability over the previous imaging system..

  11. Treatment algorithms for high-energy traumas of lower extremities

    Directory of Open Access Journals (Sweden)

    Jovanović Mladen

    2002-01-01

    Full Text Available Introduction High-energy traumas are open or closed injuries caused by force (missile, traffic injuries, crush or blust injuries, falling from heights, affecting the body surface and transferring high amount of kinetic energy inducing great damage to the tissue. Management of such lower extremity injuries has evolved over past several decades, but still remains a difficult task for every surgical team. Specific anatomic and functional characteristics combined with extensive injuries demands specific treatment protocols. Multiple injuries In a multiple injured patient the first priority is management of life-threatening trauma. Despite other injuries, surgical treatment of limb-threatening injuries must start as soon as life-threatening condition has been managed. Treatment algorithms Algorithms are especially beneficial in management of severely injured, but salvageable extremities and in making decision on amputation. Insight into mechanisms of injury, as well as systematic examination of the affected limb, should help us understand the extensiveness of trauma and make an adequate management plan. Prevention of infection and surgical approach Prevention of wound infection and surgical approach to high- energy limb trauma, which includes wound extension, wound excision, skeletal stabilization and if necessary muscle compartment release, should be done in the first 6 hours after injury. Methods of soft tissue reconstruction Commonly used methods for soft tissue defects must provide wound coverage in less than five days following injury. Rehabilitation Early passive and active mobilization and verticalization of patients is very important for successful treatment. Conclusion Good and timely evaluation of the injured and collaboration between plastic and orthopedic surgeons from the beginning of treatment, are crucial for final outcome.

  12. Demonstration, Testing and Qualification of a High Temperature, High Speed Magnetic Thrust Bearing

    Science.gov (United States)

    DeWitt, Kenneth

    2005-01-01

    The gas turbine industry has a continued interest in improving engine performance and reducing net operating and maintenance costs. These goals are being realized because of advancements in aeroelasticity, materials, and computational tools such as CFD and engine simulations. These advancements aid in increasing engine thrust-to-weight ratios, specific fuel consumption, pressure ratios, and overall reliability through higher speed, higher temperature, and more efficient engine operation. Currently, rolling element bearing and squeeze film dampers are used to support rotors in gas turbine engines. Present ball bearing configurations are limited in speed (bearings require extensive preventative maintenance in order to assure their safe operation. Since these bearings are at their operational limits, new technologies must be found in order to take advantage of other advances. Magnetic bearings are well suited to operate at extreme temperatures and higher rotational speeds and are a promising solution to the problems that conventional rolling element bearings present. Magnetic bearing technology is being developed worldwide and is considered an enabling technology for new engine designs. Using magnetic bearings, turbine and compressor spools can be radically redesigned to be significantly larger and stiffer with better damping and higher rotational speeds. These advances, a direct result of magnetic bearing technology, will allow significant increases in engine power and efficiency. Also, magnetic bearings allow for real-time, in-situ health monitoring of the system, lower maintenance costs and down time.

  13. High-Speed, Low-Power Digitizer (9725) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future detectors and arrays for visible, IR, and submillimeter imaging and spectroscopy require much higher speed digitizers than are currently available. In...

  14. High-Speed, Low-Power Digitizer II (2007037) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future detectors and arrays for visible, IR, and submillimeter imaging and spectroscopy require much higher speed digitizers than are currently available. In...

  15. Ptychographic hyperspectral spectromicroscopy with an extreme ultraviolet high harmonic comb

    CERN Document Server

    Zhang, Bosheng; Seaberg, Matthew H; Shanblatt, Elisabeth R; Porter, Christina L; Karl,, Robert; Mancuso, Christopher A; Kapteyn, Henry C; Murnane, Margaret M; Adams, Daniel E

    2016-01-01

    We demonstrate a new scheme of spectromicroscopy in the extreme ultraviolet (EUV) spectral range, where the spectral response of the sample at different wavelengths is imaged simultaneously. It is enabled by applying ptychographical information multiplexing (PIM) to a tabletop EUV source based on high harmonic generation, where four spectrally narrow harmonics near 30 nm form a spectral comb structure. Extending PIM from previously demonstrated visible wavelengths to the EUV/X-ray wavelengths promises much higher spatial resolution and more powerful spectral contrast mechanism, making PIM an attractive spectromicroscopy method in both the microscopy and the spectroscopy aspects. Besides the sample, the multicolor EUV beam is also imaged in situ, making our method a powerful beam characterization technique. No hardware is used to separate or narrow down the wavelengths, leading to efficient use of the EUV radiation.

  16. Detailed thermodynamic analyses of high-speed compressible turbulence

    Science.gov (United States)

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

    2016-11-01

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

  17. Plastic straw: future of high-speed signaling

    Science.gov (United States)

    Song, Ha Il; Jin, Huxian; Bae, Hyeon-Min

    2015-11-01

    The ever-increasing demand for bandwidth triggered by mobile and video Internet traffic requires advanced interconnect solutions satisfying functional and economic constraints. A new interconnect called E-TUBE is proposed as a cost-and-power-effective all-electrical-domain wideband waveguide solution for high-speed high-volume short-reach communication links. The E-TUBE achieves an unprecedented level of performance in terms of bandwidth-per-carrier frequency, power, and density without requiring a precision manufacturing process unlike conventional optical/waveguide solutions. The E-TUBE exhibits a frequency-independent loss-profile of 4 dB/m and has nearly 20-GHz bandwidth over the V band. A single-sideband signal transmission enabled by the inherent frequency response of the E-TUBE renders two-times data throughput without any physical overhead compared to conventional radio frequency communication technologies. This new interconnect scheme would be attractive to parties interested in high throughput links, including but not limited to, 100/400 Gbps chip-to-chip communications.

  18. Changes of indicators of high-speed and high-speed and power preparedness at volleyball players of 12–13 years old

    Directory of Open Access Journals (Sweden)

    Oleg Shevchenko

    2016-04-01

    Full Text Available Purpose: to define changes of indicators of high-speed and high-speed and power preparedness of volleyball players of 12–13 years old. Material & Methods: the test exercises, which are recommended by the training program of CYSS on volleyball, were used for the definition of the level of development of high-speed and high-speed and power abilities of volleyball players. 25 young volleyball players from the group of the previous basic preparation took part in the experiment. Sports experience of sportsmen is 3–4 years. The analysis of scientifically-methodical literature, pedagogical testing, pedagogical experiment, methods of mathematical statistics were carried out. Results: the analyzed level of high-speed and high-speed and power abilities of volleyball players. Conclusions: the results had reliable changes (t=2,2–2,4 at р<0,05 of the level of high-speed and high-speed and power abilities of volleyball players of 12–13years old in the experimental group at the end of the experiment, except run on 30 m that demonstrates a positive influence of application of special exercises in the educational-training process.

  19. High-speed imaging and wavefront sensing with an infrared avalanche photodiode array

    CERN Document Server

    Baranec, Christoph; Riddle, Reed; Hall, Donald; Jacobson, Shane; Law, Nicholas M; Chun, Mark

    2015-01-01

    Infrared avalanche photodiode arrays represent a panacea for many branches of astronomy by enabling extremely low-noise, high-speed and even photon-counting measurements at near-infrared wavelengths. We recently demonstrated the use of an early engineering-grade infrared avalanche photodiode array that achieves a correlated double sampling read noise of 0.73 e- in the lab, and a total noise of 2.52 e- on sky, and supports simultaneous high-speed imaging and tip-tilt wavefront sensing with the Robo-AO visible-light laser adaptive optics system at the Palomar Observatory 1.5-m telescope. We report here on the improved image quality achieved simultaneously at visible and infrared wavelengths by using the array as part of an image stabilization control-loop with adaptive-optics sharpened guide stars. We also discuss a newly enabled survey of nearby late M-dwarf multiplicity as well as future uses of this technology in other adaptive optics and high-contrast imaging applications.

  20. A High Performance Track and Hold Circuit for High-Resolution High-Speed ADC

    Institute of Scientific and Technical Information of China (English)

    Hua Cai; Ping Li

    2011-01-01

    Design of a high performance track and hold (T/H) circuit for high-resolution high-speed analog-to-digital converter (ADC) is presented,which has been implemented in 0.18 μm CMOS process.An improved bootstrapped and bulk-switching technique is introduced to greatly minimize the nonlinearity of sampling network over a wide bandwidth,and the addition of a modified pre-charge circuit helps reducing the total power consumption.The experimental results show that the proposed T/H circuit achieves over 77 dB SFDR (spurious-free dynamic range) and 70 dB THD (total harmonic distortion) at 100 MHz sampling rate and maintains the performance with input frequency up to 305 MHz while consuming 47 mW power.