WorldWideScience

Sample records for operating speed

  1. 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.

  2. Speed-sensing device aids crane operators

    Science.gov (United States)

    1964-01-01

    So that crane operators can judge payload movements accurately, a friction-driven multilobed cam device energizes a buzzer and indicator lamp in the crane cab. The signal frequency of this speed sensor has a sensitivity to hoist movement of 1/8 inch.

  3. 14 CFR 23.1507 - Operating maneuvering speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  4. 14 CFR 25.1505 - Maximum operating limit speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  5. 49 CFR 174.86 - Maximum allowable operating speed.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Maximum allowable operating speed. 174.86 Section... operating speed. (a) For molten metals and molten glass shipped in packagings other than those prescribed in § 173.247 of this subchapter, the maximum allowable operating speed may not exceed 24 km/hour (15...

  6. 14 CFR 29.49 - Performance at minimum operating speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Performance at minimum operating speed. 29... minimum operating speed. (a) For each Category A helicopter, the hovering performance must be determined... than helicopters, the steady rate of climb at the minimum operating speed must be determined over...

  7. 14 CFR 27.49 - Performance at minimum operating speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Performance at minimum operating speed. 27... minimum operating speed. (a) For helicopters— (1) The hovering ceiling must be determined over the ranges... climb at the minimum operating speed must be determined over the ranges of weight, altitude,...

  8. Survey of variable speed operation of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Ola; Hylander, J.; Thorborg, K. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

    1996-12-01

    During the last five years the production and operation of variable-speed wind turbines have advanced from a few experimental machines to a serial production of at least 10 MW of installed capacity of variable speed machines per week. The rated power of serial wind turbines is today around 600 kW and for the prototypes up to 3000 kW. Variable speed operation of wind turbines can be obtained with several different types of electrical generating systems, such as synchronous generators with diode rectifiers and thyristor inverters or induction generators with IGBT-converters, for the wide speed range. For the narrow speed range the wound motor induction generator with a rotor cascade or a controlled rotor resistance is preferable. The development of permanent magnetic material and the reduction of costs of the power electronic components have opened a possibility of designing cost-effective wind turbines with a directly driven generator. Pitch control together with variable speed will make it possible to limit the power variation within a few percent, 2 to 5 %, of the rated power. 7 refs, 4 figs, 2 tabs

  9. Application of operational car crew universal speed stenogram

    Directory of Open Access Journals (Sweden)

    Volodymyr Gradusov

    2014-12-01

    Full Text Available Purpose: experimentally to check up possibility and efficiency of application of operative cars of universal speed shorthand records of unknown roads crews. Materials and Methods: theoretical analysis and generalization, pedagogical supervisions, pedagogical experiment, methods of mathematical statistics. In research took part 20 professional crews road patrol State Automobile Inspectorate, in all 40 persons, up-diffused on 2 groups for 10 crews: experimental and control. Results: application of methods of universal speed shorthand record of СД an experimental group allowed to shorten time-of-flight of segment of control distance on 7,37%. Conclusion: the results of pedagogical experiment at participation of professional crews road patrol State Automobile Inspectorate on official cars in the contention terms of the real route testify to possibility and efficiency of application of operative cars of the special setting of universal speed shorthand records of unknown roads crews during their professional activity.

  10. Short-Term Wind Speed Forecasting for Power System Operations

    KAUST Repository

    Zhu, Xinxin

    2012-04-01

    The emphasis on renewable energy and concerns about the environment have led to large-scale wind energy penetration worldwide. However, there are also significant challenges associated with the use of wind energy due to the intermittent and unstable nature of wind. High-quality short-term wind speed forecasting is critical to reliable and secure power system operations. This article begins with an overview of the current status of worldwide wind power developments and future trends. It then reviews some statistical short-term wind speed forecasting models, including traditional time series approaches and more advanced space-time statistical models. It also discusses the evaluation of forecast accuracy, in particular, the need for realistic loss functions. New challenges in wind speed forecasting regarding ramp events and offshore wind farms are also presented. © 2012 The Authors. International Statistical Review © 2012 International Statistical Institute.

  11. Operational Modal Analysis of Wind Turbine Speed-increase Gearbox

    Directory of Open Access Journals (Sweden)

    LI Yafeng

    2013-11-01

    Full Text Available Speed increase transmission gear box is the primary vibration and noise source of wind turbine, Operational modal method was adopted to collect impact data and response data of each point based on the gearbox test model. ANSYS finite element model is established to simulate the wind turbine gearbox. Then the modal frequencies of the two methods were compared to ensure the test model is correct. The results show that operational modal method can be applied in wind turbine gearbox modal analysis and it has important guiding significance to gearbox fault diagnosis and reliability and maintainability improving.  

  12. High-Speed Operation of Interband Cascade Lasers

    Science.gov (United States)

    Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Wright, Malcom W.; Farr, William H.; Yang, Rui Q.; Liu, H. C.

    2010-01-01

    Optical sources operating in the atmospheric window of 3-5 microns are of particular interest for the development of free-space optical communication link. It is more advantageous to operate the free-space optical communication link in 3-5-microns atmospheric transmission window than at the telecom wavelength of 1.5 m due to lower optical scattering, scintillation, and background radiation. However, the realization of optical communications at the longer wavelength has encountered significant difficulties due to lack of adequate optical sources and detectors operating in the desirable wavelength regions. Interband Cascade (IC) lasers are novel semiconductor lasers that have a great potential for the realization of high-power, room-temperature optical sources in the 3-5-microns wavelength region, yet no experimental work, until this one, was done on high-speed direct modulation of IC lasers. Here, highspeed interband cascade laser, operating at wavelength 3.0 m, has been developed and the first direct measurement of the laser modulation bandwidth has been performed using a unique, highspeed quantum well infrared photodetector (QWIP). The developed laser has modulation bandwidth exceeding 3 GHz. This constitutes a significant increase of the IC laser modulation bandwidth over currently existing devices. This result has demonstrated suitability of IC lasers as a mid-IR light source for multi-GHz free-space optical communications links

  13. INFLUENCE OF OPERABILITY CRITERIA LIMITING VALUES ON SHIP SPEED

    Directory of Open Access Journals (Sweden)

    Jasna Prpić-Oršić

    2016-09-01

    Full Text Available When the ship is caught in heavy seas, there are two manoeuvres that the shipmaster can undertake to avoid excessive ship motion and hull damage: changing course or voluntary speed reduction. This paper presents a study of the effect of the various voluntary speed reduction criteria to attainable speed of ship on seaway. The speed loss is calculated by taking into account wind and wave effect on ship speed, the engine and propeller performance in actual seas as well as the mass inertia of the ship. The attainable ship speed for ship in head, following and beam waves by accounting for voluntary speed reduction is estimated for various significant wave height. The criteria of slamming, deck wetness, propeller emergence, excessive accelerations and roll are taken into account. The impact of variations of the limiting values of certain criteria due to which the captain intentionally reduces the ship speed is analysed and discussed.

  14. 49 CFR 213.9 - Classes of track: operating speed limits.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Classes of track: operating speed limits. 213.9... speed limits. (a) Except as provided in paragraph (b) of this section and §§ 213.57(b), 213.59(a), 213.113(a), and 213.137(b) and (c), the following maximum allowable operating speeds apply— Over...

  15. An Algorithm for the Optimal Matching Speeds of Passenger and Freight Trains in Mixed Operations

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    This paper models the calculation of the optimal matching speeds of passenger and freight trains with various stage control methods for speed in mixed operations, presents a algorithm for the solution and justifies it with a practical example.

  16. 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.

  17. 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.

  18. Performance Improvement of Servo Machine Low Speed Operation Using RBFN Disturbance Observer

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2004-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Networks (RBFN) is applied. The effectiveness of the proposed inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed...

  19. Robust and Stable Disturbance Observer of Servo System for Low-Speed Operation

    DEFF Research Database (Denmark)

    Lee, Kyo Beum; Blaabjerg, Frede

    2007-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of inertia. To esti......A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...

  20. On the maximum speed of operation of a quantum "black box"

    CERN Document Server

    Dugic, M

    2001-01-01

    We investigate the minimum time needed for (i.e. the maximum speed of) a quantum "black box" ("oracle") operation which employs "quantum parallelism" to be executed. We emphasize that the operation considered employs the quantum-measurement-like establishing of entanglement in the composite system "input register + output register" of a quantum computer's hardware, and we show that the speed of the operation can be increased by increasing the coupling (strength of interaction) in the composite system, as well as by some local operations (e.g., a proper state preparation) performed on the output register. It also proves that the operation employing a macroscopic (or at least a mesoscopic) system to mediate the registers' interaction should be much faster than the operation performed through direct registers' interaction. Finally, we show that adding energy to the composite system needs not to speed up the operation considered. Rather, e.g., in the case of mutually directly interacting registers, the requiremen...

  1. New geometric design consistency model based on operating speed profiles for road safety evaluation.

    Science.gov (United States)

    Camacho-Torregrosa, Francisco J; Pérez-Zuriaga, Ana M; Campoy-Ungría, J Manuel; García-García, Alfredo

    2013-12-01

    To assist in the on-going effort to reduce road fatalities as much as possible, this paper presents a new methodology to evaluate road safety in both the design and redesign stages of two-lane rural highways. This methodology is based on the analysis of road geometric design consistency, a value which will be a surrogate measure of the safety level of the two-lane rural road segment. The consistency model presented in this paper is based on the consideration of continuous operating speed profiles. The models used for their construction were obtained by using an innovative GPS-data collection method that is based on continuous operating speed profiles recorded from individual drivers. This new methodology allowed the researchers to observe the actual behavior of drivers and to develop more accurate operating speed models than was previously possible with spot-speed data collection, thereby enabling a more accurate approximation to the real phenomenon and thus a better consistency measurement. Operating speed profiles were built for 33 Spanish two-lane rural road segments, and several consistency measurements based on the global and local operating speed were checked. The final consistency model takes into account not only the global dispersion of the operating speed, but also some indexes that consider both local speed decelerations and speeds over posted speeds as well. For the development of the consistency model, the crash frequency for each study site was considered, which allowed estimating the number of crashes on a road segment by means of the calculation of its geometric design consistency. Consequently, the presented consistency evaluation method is a promising innovative tool that can be used as a surrogate measure to estimate the safety of a road segment.

  2. Dynamic analysis of a high-speed train operating on a curved track with failed fasteners

    Institute of Scientific and Technical Information of China (English)

    Li ZHOU; Zhi-yun SHEN

    2013-01-01

    A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners.The model considers a high-speed train consisting of eight vehicles coupled with a ballasted track.The vehicle is modeled as a multi-body system,and the rail is modeled with a Timoshenko beam resting on the discrete sleepers.The vehicle model considers the effect of the end connections of the neighboring vehicles on the dynamic behavior.The track model takes into account the lateral,vertical,and torsional deformations of the rails and the effect of the discrete sleeper support on the coupling dynamics of the vehicles and the track.The sleepers are assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed.The train model couples with the track model by using a Hertzian contact model for the wheel/rail normal force calculation,and the nonlinear creep theory by Shen et al.(1984) is used for wheel/rail tangent force calculation.In the analysis,a curved track of 7000-m radius with failed fasteners is selected,and the effects of train operational speed and the number of failed fasteners on the dynamic behaviors of the train and the track are investigated in detail.Furthermore,the wheel/rail forces and derailment coefficient and the wheelset loading reduction are analyzed when the high-speed train passes over the curved track with the different number of continuously failed fasteners at different operational speeds.Through the detailed numerical analysis,it is found that the high-speed train can operate normally on the curved track of 7000-m radius at the speeds of 200 km/h to 350 km/h.

  3. Analysis of Variable Speed Optimization Operation Effect of Different-type Pumps in Jiangdu Pumping Station

    Science.gov (United States)

    Jinxian, Qiu; Jilin, Cheng; Jinyao, Luo; Rentian, Zhang; Lihua, Zhang; Yi, Gong

    2010-06-01

    The following paper puts forward 45 combination schemes of different-type pumps in different daily-average heads and operation loads in Jiangdu Pumping Station. Based on every scheme, the minimum electricity consumption cost selected as the objective function, this paper gives the results of variable speed optimal operations with dynamic planning methods in both considering time-sharing electricity prices and not, simultaneously, it gives the results of fixed speed conventional operation considering time-sharing electricity prices. Then according to the unit energy consumption cost, the paper gives comparison analysis of the effect of different-type pumps in variable speed optimization operation, the conclusions can offer decision-making bases for optimization research of pumping stations considering time-sharing electricity prices and tide levels of Yangtze River, and offer references for transformation and economical operation of large and medium-size pumping stations.

  4. WIND TURBINE OPERATION PARAMETER CHARACTERISTICS AT A GIVEN WIND SPEED

    Directory of Open Access Journals (Sweden)

    Zdzisław Kamiński

    2014-06-01

    Full Text Available This paper discusses the results of the CFD simulation of the flow around Vertical Axis Wind Turbine rotor. The examined rotor was designed following patent application no. 402214. The turbine operation is characterised by parameters, such as opening angle of blades, power, torque, rotational velocity at a given wind velocity. Those parameters have an impact on the performance of entire assembly. The distribution of forces acting on the working surfaces in the turbine can change, depending on the angle of rotor rotation. Moreover, the resultant force derived from the force acting on the oncoming and leaving blades should be as high as possible. Accordingly, those parameters were individually simulated over time for each blade in three complete rotations. The attempts to improve the performance of the entire system resulted in a new research trend to improve the performance of working turbine rotor blades.

  5. Operational amplifier speed and accuracy improvement analog circuit design with structural methodology

    CERN Document Server

    Ivanov, Vadim V

    2004-01-01

    Operational Amplifier Speed and Accuracy Improvement proposes a new methodology for the design of analog integrated circuits. The usefulness of this methodology is demonstrated through the design of an operational amplifier. This methodology consists of the following iterative steps: description of the circuit functionality at a high level of abstraction using signal flow graphs; equivalent transformations and modifications of the graph to the form where all important parameters are controlled by dedicated feedback loops; and implementation of the structure using a library of elementary cells. Operational Amplifier Speed and Accuracy Improvement shows how to choose structures and design circuits which improve an operational amplifier's important parameters such as speed to power ratio, open loop gain, common-mode voltage rejection ratio, and power supply rejection ratio. The same approach is used to design clamps and limiting circuits which improve the performance of the amplifier outside of its linear operat...

  6. Operation ranges and dynamic capabilities of variable-speed pumped-storage hydropower

    Science.gov (United States)

    Mercier, Thomas; Olivier, Mathieu; Dejaeger, Emmanuel

    2017-04-01

    The development of renewable and intermittent power generation creates incentives for the development of both energy storage solutions and more flexible power generation assets. Pumped-storage hydropower (PSH) is the most established and mature energy storage technology, but recent developments in power electronics have created a renewed interest by providing PSH units with a variable-speed feature, thereby increasing their flexibility. This paper reviews technical considerations related to variable-speed PSH in link with the provision of primary frequency control, also referred to as frequency containment reserves (FCRs). Based on the detailed characteristics of a scale model pump-turbine, the variable-speed operation ranges in pump and turbine modes are precisely assessed and the implications for the provision of FCRs are highlighted. Modelling and control for power system studies are discussed, both for fixed- and variable-speed machines and simulation results are provided to illustrate the high dynamic capabilities of variable-speed PSH.

  7. Repressing the effects of variable speed harmonic orders in operational modal analysis

    Science.gov (United States)

    Randall, R. B.; Coats, M. D.; Smith, W. A.

    2016-10-01

    Discrete frequency components such as machine shaft orders can disrupt the operation of normal Operational Modal Analysis (OMA) algorithms. With constant speed machines, they have been removed using time synchronous averaging (TSA). This paper compares two approaches for varying speed machines. In one method, signals are transformed into the order domain, and after the removal of shaft speed related components by a cepstral notching method, are transformed back to the time domain to allow normal OMA. In the other simpler approach an exponential shortpass lifter is applied directly in the time domain cepstrum to enhance the modal information at the expense of other disturbances. For simulated gear signals with speed variations of both ±5% and ±15%, the simpler approach was found to give better results The TSA method is shown not to work in either case. The paper compares the results with those obtained using a stationary random excitation.

  8. Unsteady Operation of New Type Turbofan Engine with Aerodynamic Torque Converter Reducing Front Fan Speed

    Institute of Scientific and Technical Information of China (English)

    Toshiaki KANEMOTO; Seita SEKI; Kazunori IDENO; Ahmed Mohamed GALAL

    2005-01-01

    It is desired to increase the rotational speed of the core engine of the turbofan so as to get the best efficiency for the next leap of engine technology. The conventional mechanism in which the front fan is directly connected to the output shaft of a core engine, have a limit of increasing the spool speed, because the fan diameter is very large. The authors have proposed a new driving system in which the front fan is driven through the aerodynamic torque converter. The front fan can work at the best performance at slower speed while the core engine runs more efficiently at higher speed. Continuously, this paper discusses the response of the front fan in the unsteady operation of the core engine, accompanying with the internal flow. The system has the acceptable responsibility in the unsteady operation which is very important for the aircrafts.

  9. The experimental studies of operating modes of a diesel-generator set at variable speed

    Science.gov (United States)

    Obukhov, S. G.; Plotnikov, I. A.; Surkov, M. A.; Sumarokova, L. P.

    2017-02-01

    A diesel generator set working at variable speed to save fuel is studied. The results of experimental studies of the operating modes of an autonomous diesel generator set are presented. Areas for regulating operating modes are determined. It is demonstrated that the transfer of the diesel generator set to variable speed of the diesel engine makes it possible to improve the energy efficiency of the autonomous generator source, as well as the environmental and ergonomic performance of the equipment as compared with general industrial analogues.

  10. High-speed flow visualization in a pump-turbine under off-design operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hasmatuchi, V; Roth, S; Botero, F; Avellan, F; Farhat, M, E-mail: vlad.hasmatuchi@epfl.c [Laboratory for Hydraulic Machines, Ecole Polytechnique Federale de Lausanne Av. de Cour 33bis, Lausanne, CH-1007 (Switzerland)

    2010-08-15

    The flow hydrodynamics in a low specific speed radial pump-turbine reduced scale model is experimentally investigated under off-design operating conditions in generating mode. Wall pressure measurements, in the stator, synchronized with high-speed flow visualizations in the vaneless space between the impeller and the guide vanes using air bubbles injection are performed. When starting from the best efficiency point and increasing the runner speed, a significant increase of the pressure fluctuations is observed mainly in channels between wicket gates. The spectral analysis shows a rise of one stall cell, rotating with about 70% of the impeller frequency, at runaway, which further increases as the zero discharge condition is approached. Then a specific image processing technique is detailed and applied to create a synthetic instantaneous view of the flow pattern on the entire guide vanes circumference for an operating point in turbine-brake mode, where backflow and vortices accompany the stall passage.

  11. Gain-scheduled Linear Quadratic Control of Wind Turbines Operating at High Wind Speed

    DEFF Research Database (Denmark)

    Østergaard, Kasper Zinck; Stoustrup, Jakob; Brath, Per

    2007-01-01

    This paper addresses state estimation and linear quadratic (LQ) control of variable speed variable pitch wind turbines. On the basis of a nonlinear model of a wind turbine, a set of operating conditions is identified and a LQ controller is designed for each operating point. The controller gains....... Simulation results are given that display good performance of the observers and comparisons with a controller designed by classical methods displays the potential of the method.  ...

  12. 49 CFR 213.307 - Class of track: operating speed limits.

    Science.gov (United States)

    2010-10-01

    ... hazardous material, as defined at 49 CFR 171.8, except as provided in Column 9A of the Hazardous Materials Table (49 CFR 172.101) for movement in the same train as a passenger-carrying vehicle or in Column 9B of... 49 Transportation 4 2010-10-01 2010-10-01 false Class of track: operating speed limits....

  13. Variable speed induction motor operation from a 20-kHz power bus

    Science.gov (United States)

    Hansen, Irving G.

    Induction motors are recognized for their simple rugged construction to date, however, their application to variable speed or servo drives has been hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation offrequency and voltage allows independent control of rotor and stator flux, full four-quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.

  14. Operational Influence on Thermal Behavior of High-Speed Helical Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Kilmain, Charles J.

    2006-01-01

    An experimental effort has been conducted on an aerospace-quality helical gear train to investigate the thermal behavior of the gear system as many important operational conditions were varied. Drive system performance measurements were made at varying speeds and loads (to 5,000 hp and 15,000 rpm). Also, an analytical effort was undertaken for comparison to the measured results. The influence of the various loss mechanisms from the analysis for this high speed helical gear train gearbox will be presented and compared to the experimental results.

  15. A high-speed CMOS current op amp for very low supply voltage operation

    DEFF Research Database (Denmark)

    Bruun, Erik

    1994-01-01

    A CMOS implementation of a high-gain current mode operational amplifier (op amp) with a single-ended input and a differential output is described. This configuration is the current mode counterpart of the traditional voltage mode op amp. In order to exploit the inherent potential for high speed......, low voltage operation normally associated with current mode analog signal processing, the op amp has been designed to operate off a supply voltage of 1.5 V, and the signal path has been confined to N-channel transistors. With this design, a gain of 94 dB and a gain-bandwidth product of 65 MHz has been...

  16. Strategy for the Operation of Cooling Towers with variable Speed Fans

    CERN Document Server

    Iñigo-Golfín, J

    2001-01-01

    Within the SPS Cooling Water Project at CERN aimed at the reduction of water consumption, this primary open cooling loop will be closed and all the primary cooling circuit components will be upgraded to the new required duty and brought to the necessary safety and operability standards. In particular the tower fans will be fitted with variable frequency drives to replace the existing two speed motors. This paper presents a study to optimize the operation of SPS cooling towers taking into account outdoor conditions (wet and dry bulb temperatures) and the entirety of the primary circuit in which they will operate.

  17. Gait Speed and Operative Mortality in Older Adults Following Cardiac Surgery.

    Science.gov (United States)

    Afilalo, Jonathan; Kim, Sunghee; O'Brien, Sean; Brennan, J Matthew; Edwards, Fred H; Mack, Michael J; McClurken, James B; Cleveland, Joseph C; Smith, Peter K; Shahian, David M; Alexander, Karen P

    2016-06-01

    Prediction of operative risk is a critical step in decision making for cardiac surgery. Existing risk models may be improved by integrating a measure of frailty, such as 5-m gait speed, to better capture the heterogeneity of the older adult population. To determine the association of 5-m gait speed with operative mortality and morbidity in older adults undergoing cardiac surgery. A prospective cohort study was conducted from July 1, 2011, to March 31, 2014, at 109 centers participating in the Society of Thoracic Surgeons Adult Cardiac Surgery Database. The 5-m gait speed test was performed in 15 171 patients aged 60 years or older undergoing coronary artery bypass graft, aortic valve surgery, mitral valve surgery, or combined procedures. All-cause mortality during the first 30 days after surgery; secondarily, a composite outcome of mortality or major morbidity during the index hospitalization. Among the cohort of 15 171 patients undergoing cardiac surgery, the median age was 71 years and 4622 were female (30.5%). Compared with patients in the fastest gait speed tertile (>1.00 m/s), operative mortality was increased for those in the middle tertile (0.83-1.00 m/s; odds ratio [OR], 1.77; 95% CI, 1.34-2.34) and slowest tertile (cardiac surgery, with each 0.1-m/s decrease conferring an 11% relative increase in mortality. Gait speed can be used to refine estimates of operative risk, to support decision-making and, since incremental value is modest when used as a sole criterion for frailty, to screen older adults who could benefit from further assessment.

  18. Design of Stirrer Impeller with Variable Operational Speed for a Food Waste Homogenizer

    Directory of Open Access Journals (Sweden)

    Idris A. Kayode

    2016-05-01

    Full Text Available A conceptualized impeller called KIA is designed for impact agitation of food waste in a homogenizer. A comparative analysis of the performance of KIA is made with three conventional impeller types, Rushton, Anchor, and Pitched Blade. Solid–liquid mixing of a moisture-rich food waste is simulated under various operational speeds, in order to compare the dispersions and thermal distributions at homogenous slurry conditions. Using SolidWorks, the design of the impellers employs an Application Programming Interface (API which acts as the canvas for creating a graphical user interface (GUI for automation of its assembly. A parametric analysis of the homogenizer, at varying operational speeds, enables the estimation of the critical speed of the mixing shaft diameter and the deflection under numerous mixing conditions and impeller configurations. The numerical simulation of the moisture-rich food waste (approximated as a Newtonian carrot–orange soup is performed with ANSYS CFX v.15.0. The velocity and temperature field distribution of the homogenizer for various impeller rotational speeds are analyzed. It is anticipated that the developed model will help in the selection of a suitable impeller for efficient mixing of food waste in the homogenizer.

  19. Optimization of a PCRAM Chip for high-speed read and highly reliable reset operations

    Science.gov (United States)

    Li, Xiaoyun; Chen, Houpeng; Li, Xi; Wang, Qian; Fan, Xi; Hu, Jiajun; Lei, Yu; Zhang, Qi; Tian, Zhen; Song, Zhitang

    2016-10-01

    The widely used traditional Flash memory suffers from its performance limits such as its serious crosstalk problems, and increasing complexity of floating gate scaling. Phase change random access memory (PCRAM) becomes one of the most potential nonvolatile memories among the new memory techniques. In this paper, a 1M-bit PCRAM chip is designed based on the SMIC 40nm CMOS technology. Focusing on the read and write performance, two new circuits with high-speed read operation and highly reliable reset operation are proposed. The high-speed read circuit effectively reduces the reading time from 74ns to 40ns. The double-mode reset circuit improves the chip yield. This 1M-bit PCRAM chip has been simulated on cadence. After layout design is completed, the chip will be taped out for post-test.

  20. Development of control strategy of variable speed limits for improving traffic operations at freeway bottlenecks

    Institute of Scientific and Technical Information of China (English)

    李志斌; 刘攀; 王炜; 徐铖铖

    2014-01-01

    A control strategy of variable speed limits (VSL) was developed to reduce the travel time at freeway recurrent bottleneck areas. The proposed control strategy particularly focused on preventing the capacity drop and increasing the discharge flow. A cell transmission model (CTM) was developed to evaluate the effects of the proposed VSL control strategy on the traffic operations. The results show that the total travel time is reduced by 25.5% and the delay is reduced by 56.1%. The average travel speed is increased by 34.3% and the queue length is reduced by 31.0%. The traffic operation is improved by the proposed VSL control strategy. The way to use the proposed VSL control strategy in different types of freeway bottlenecks was also discussed by considering different traffic flow characteristics. It is concluded that the VSL control strategy is effective for merge bottlenecks but is less effective for diverge bottlenecks.

  1. Modeling and Operational Testing of an Isolated Variable Speed PMSG Wind Turbine with Battery Energy Storage

    OpenAIRE

    BAROTE, L.; MARINESCU, C.

    2012-01-01

    This paper presents the modeling and operational testing of an isolated permanent magnet synchronous generator (PMSG), driven by a small wind turbine with a battery energy storage system during wind speed and load variations. The whole system is initially modeled, including the PMSG, the boost converter and the storage system. The required power for the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropri...

  2. Development and Evaluation of Bus Operation Control System Based on Cooperative Speed Guidance

    Directory of Open Access Journals (Sweden)

    Jing Teng

    2015-01-01

    Full Text Available Buses often have strong bunching or large interval tendency when traveling further along the route. To restrain this further deterioration of operation service, this paper developed a bus operation control system to dynamically adjust bus speed, bus dwell time, and traffic signal timings along the running path. In addition, a simulation platform was developed to evaluate the proposed control system with the actual data collected from bus route number 210 in Shanghai. The simulation results show that the proposed control system can mitigate the amplification trend of the headway deviation along the route to produce headways within a given tolerance.

  3. Gas Bearing Control for Safe Operation in Critical Speed Regions - Experimental Verification

    DEFF Research Database (Denmark)

    Theisen, Lukas R. S.; Niemann, Hans H.; Galeazzi, Roberto

    2015-01-01

    Gas bearings are popular for their high speed capabilities, low friction and clean operation, but require low clearances and suffer from poor damping properties. The poor damping properties cause high disturbance amplification near the natural frequencies. These become critical when the rotation...... supported by gas bearings to extend their operating range. Using H∞-design methods, active lubrication techniques are proposed to enhance the damping, which in turn reduces the vibrations to a desired safe level. The control design is validated experimentally on a laboratory test rig, and shown to allow...

  4. High-speed operation of optical exclusive OR circuit based on balanced detection and intensity modulation

    Directory of Open Access Journals (Sweden)

    Koichi Takiguchi

    2015-12-01

    Full Text Available We report the evaluated results of an optical exclusive OR (XOR circuit for high-speed binary signals, which operates based on balanced detection and intensity modulation. This circuit partly adopts simple electronics in order to achieve simple configuration and operation. Two input optical binary signals into a balanced photo detector produce an electrical signal for directly driving a modulator. The modulator modulates the lightwave from a laser diode and generates optical XOR output of the two input optical signals. After briefly explaining its configuration and operating principle, We demonstrate some experimental results to show its potential. We show its successful operation at 40 Gbit/s binary signals including bit error rate measurement.

  5. Progress in load prediction for speed-no-load operation in Francis turbines

    Science.gov (United States)

    Mende, C.; Weber, W.; Seidel, U.

    2016-11-01

    Francis turbines are increasingly required to operate from 0-100% of power output. For the design of these turbines, a sound understanding of formerly “off-design” operating points, e.g. speed-no-load, is necessary. One way to assess loads at these operating points is to apply scale resolving CFD methods in order to account for the broad-band turbulence spectrum. This results in stochastic load patterns, which are characteristic for these off-design points. In this paper, two CFD approaches for scale resolving simulations are applied to a Francis model turbine to resolve the larger anisotropic scales in turbine flow at speed-no-load operation. The first uses a hybrid RANS-LES model presented by Menter & Egorov [2]. Here the resolved scales are adapted continuously by RANS-LES blending based on the actual flow condition. The second approach is a LES with a dynamic model based on Germano et al. [3]. For both approaches, spectra of resulting pressure fluctuations at the draft tube cone wall are presented. Additionally, pressure loads from LES are applied to calculate mean and dynamic stresses. The dynamic stresses are finally compared with measurements in the corresponding prototype turbine.

  6. High speed rail trends, technologies and operational patterns: a comparison of established and emerging networks

    Directory of Open Access Journals (Sweden)

    Roberto PALACIN

    2014-10-01

    Full Text Available This paper is set within the framework of the RailNewcastle Summer School program 2014 run by Newcastle University (UK. It presents a short history of high speed rail describing its main design and operational characteristics. The focus of the paper is on assessing the two key distinct models emerging from this trend: the Japanese or Shinkansen model and the French or TGV model. The study then applies these two models to an emerging high speed network such as the planned corridors in California (U.S. to assess the extent of applicability and suitability of applying established high speed models to the Californian network. The results suggest that a suitable possibility would be to apply the French model for the operational aspects given the similarities in terms of geography, population distribution and distance. Implementing the lessons learned from the Japanese model in terms of construction and infrastructure design would be more suitable given the striking similarities in geological characteristics linked to the latent earthquake threat.

  7. Design of operation parameters of a high speed TDI CCD line scan camera

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper analyzes the operation parameters of the time delay and integration (TDI) line scan CCD camera, such as resolution, line rate, clock frequency, etc. and their mathematical relationship is deduced. By analyzing and calculating these parameters, the working clocks of the TDI CCD line scan camera are designed,which guarantees the synchronization of the line scan rate and the camera movement speed. The IL - E2 TDI CCD of DALSA Co. is used as the sensor of the camera in the paper. The working clock generator used for the TDI CCD sensor is realized by using the programmable logic device (PLD). The experimental results show that the working clock generator circuit satisfies the requirement of high speed TDI CCD line scan camera.

  8. 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...

  9. Robust and Stable Disturbance Observer of Servo System for Low Speed Operation Using the Radial Basis Function Network

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2005-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of inertia. To esti......A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...

  10. FINITE ELEMENT ANALYSIS FOR CHIP FORMATION IN HIGH SPEED TURNING OPERATIONS BY ARBITRARY LAGRANGIAN EULERIAN METHOD

    Institute of Scientific and Technical Information of China (English)

    USAMA Umer; XIE Lijing; WANG Xibin

    2006-01-01

    A two-dimensional finite element (FE) model for the high speed turning operations when orthogonally machining AISI H13 tool steel at 49HRC using poly crystalline cubic boron nitride(PCBN) is described. An arbitrary Lagrangian Eulerian (ALE) method has been adopted which does not need any chip separation criteria as opposed to the traditional Lagrangian approach. Through FE simulations temperature and stresses distributions are presented that could be helpful in predicting tool life and improving process parameters. The results show that high temperatures are generated along the tool rake face as compared to the shear zone temperatures due to high thermal conductivity of PCBN tools.

  11. The impact of materials technology and operational constraints on the economics of cruise speed selection

    Science.gov (United States)

    Clauss, J. S., Jr.; Bruckman, F. A.; Horning, D. L.; Johnston, R. H.; Werner, J. V.

    1981-01-01

    Six material concepts at Mach 2.0 and three material concepts at Mach 2.55 were proposed. The resulting evaluations, based on projected development, production, and operating costs, indicate that aircraft designs with advanced composites as the primary material ingredient have the lowest fare premiums at both Mach 2.0 and 2.55. Designs having advanced metallics as the primary material ingredient are not economical. Advanced titanium, employing advanced manufacturing methods such as SFF/DB, requires a fare premium of about 30 percent at both Mach 2.0 and 2.55. Advanced aluminum, usable only at the lower Mach number, requires a fare premium of 20 percent. Cruise speeds in the Mach 2.0-2.3 regime are preferred because of the better economics and because of the availability of two material concepts to reduce program risk - advanced composites and advanced aluminums. This cruise speed regime also avoids the increase in risk associated with the more complex inlets and airframe systems and higher temperature composite matrices required at the higher Mach numbers typified by Mach 2.55.

  12. Study and Performance Analysis of High Frequency and High Speed Operational Amplifier

    Directory of Open Access Journals (Sweden)

    Puneet Goyal

    2013-03-01

    Full Text Available The performance analysis of the two stage CMOS operational amplifiers employing Miller capacitor in conjunction with the common gate current buffer is presented. Unlike the previously reported design strategies of the opamp of this type, this results in the opamp with a lower power supply requirements, better phase margin and better speed. The Opamp is designed to exhibit a unity gain frequency of 1.46GHz and exhibits a gain of 115dB with a 117˚ phase margin. The slew rate is found as high as 50 V/µs. Power supply noise rejection is also better in case of current buffer compensation. As compared to the conventional approach, the current buffer compensation method results in a higher unity gain frequency hence higher bandwidth under the same load condition. Simulation has been carried out in LT-SPICE

  13. Modeling and Operational Testing of an Isolated Variable Speed PMSG Wind Turbine with Battery Energy Storage

    Directory of Open Access Journals (Sweden)

    BAROTE, L.

    2012-05-01

    Full Text Available This paper presents the modeling and operational testing of an isolated permanent magnet synchronous generator (PMSG, driven by a small wind turbine with a battery energy storage system during wind speed and load variations. The whole system is initially modeled, including the PMSG, the boost converter and the storage system. The required power for the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropriate control method. Energy storage devices are required for power balance and power quality in stand alone wind energy systems. The main purpose is to supply 230 V / 50 Hz domestic appliances through a single-phase inverter. The experimental waveforms, compared to the simulation results, show a good prediction of the electrical variable parameters. Furthermore, it can be seen that the results validate the stability of the supply.

  14. Partial inversion of elliptic operator to speed up computation of likelihood in Bayesian inference

    KAUST Repository

    Litvinenko, Alexander

    2017-08-09

    In this paper, we speed up the solution of inverse problems in Bayesian settings. By computing the likelihood, the most expensive part of the Bayesian formula, one compares the available measurement data with the simulated data. To get simulated data, repeated solution of the forward problem is required. This could be a great challenge. Often, the available measurement is a functional $F(u)$ of the solution $u$ or a small part of $u$. Typical examples of $F(u)$ are the solution in a point, solution on a coarser grid, in a small subdomain, the mean value in a subdomain. It is a waste of computational resources to evaluate, first, the whole solution and then compute a part of it. In this work, we compute the functional $F(u)$ direct, without computing the full inverse operator and without computing the whole solution $u$. The main ingredients of the developed approach are the hierarchical domain decomposition technique, the finite element method and the Schur complements. To speed up computations and to reduce the storage cost, we approximate the forward operator and the Schur complement in the hierarchical matrix format. Applying the hierarchical matrix technique, we reduced the computing cost to $\\\\mathcal{O}(k^2n \\\\log^2 n)$, where $k\\\\ll n$ and $n$ is the number of degrees of freedom. Up to the $\\\\H$-matrix accuracy, the computation of the functional $F(u)$ is exact. To reduce the computational resources further, we can approximate $F(u)$ on, for instance, multiple coarse meshes. The offered method is well suited for solving multiscale problems. A disadvantage of this method is the assumption that one has to have access to the discretisation and to the procedure of assembling the Galerkin matrix.

  15. High Speed Operation and Testing of a Fault Tolerant Magnetic Bearing

    Science.gov (United States)

    DeWitt, Kenneth; Clark, Daniel

    2004-01-01

    Research activities undertaken to upgrade the fault-tolerant facility, continue testing high-speed fault-tolerant operation, and assist in the commission of the high temperature (1000 degrees F) thrust magnetic bearing as described. The fault-tolerant magnetic bearing test facility was upgraded to operate to 40,000 RPM. The necessary upgrades included new state-of-the art position sensors with high frequency modulation and new power edge filtering of amplifier outputs. A comparison study of the new sensors and the previous system was done as well as a noise assessment of the sensor-to-controller signals. Also a comparison study of power edge filtering for amplifier-to-actuator signals was done; this information is valuable for all position sensing and motor actuation applications. After these facility upgrades were completed, the rig is believed to have capabilities for 40,000 RPM operation, though this has yet to be demonstrated. Other upgrades included verification and upgrading of safety shielding, and upgrading control algorithms. The rig will now also be used to demonstrate motoring capabilities and control algorithms are in the process of being created. Recently an extreme temperature thrust magnetic bearing was designed from the ground up. The thrust bearing was designed to fit within the existing high temperature facility. The retrofit began near the end of the summer, 04, and continues currently. Contract staff authored a NASA-TM entitled "An Overview of Magnetic Bearing Technology for Gas Turbine Engines", containing a compilation of bearing data as it pertains to operation in the regime of the gas turbine engine and a presentation of how magnetic bearings can become a viable candidate for use in future engine technology.

  16. Rolling element bearing defect diagnosis under variable speed operation through angle synchronous averaging of wavelet de-noised estimate

    Science.gov (United States)

    Mishra, C.; Samantaray, A. K.; Chakraborty, G.

    2016-05-01

    Rolling element bearings are widely used in rotating machines and their faults can lead to excessive vibration levels and/or complete seizure of the machine. Under special operating conditions such as non-uniform or low speed shaft rotation, the available fault diagnosis methods cannot be applied for bearing fault diagnosis with full confidence. Fault symptoms in such operating conditions cannot be easily extracted through usual measurement and signal processing techniques. A typical example is a bearing in heavy rolling mill with variable load and disturbance from other sources. In extremely slow speed operation, variation in speed due to speed controller transients or external disturbances (e.g., varying load) can be relatively high. To account for speed variation, instantaneous angular position instead of time is used as the base variable of signals for signal processing purposes. Even with time synchronous averaging (TSA) and well-established methods like envelope order analysis, rolling element faults in rolling element bearings cannot be easily identified during such operating conditions. In this article we propose to use order tracking on the envelope of the wavelet de-noised estimate of the short-duration angle synchronous averaged signal to diagnose faults in rolling element bearing operating under the stated special conditions. The proposed four-stage sequential signal processing method eliminates uncorrelated content, avoids signal smearing and exposes only the fault frequencies and its harmonics in the spectrum. We use experimental data1

  17. IMPROVED METHOD OF DETERMINATION OF ECONOMIC EFFICIENCY OF CONSTRUCTION AND OPERATION OF HIGH SPEED MAINLINE IN UKRAINE

    Directory of Open Access Journals (Sweden)

    YU. S. Barash

    2014-01-01

    Full Text Available Purpose. To develop an advanced methodology and formulate the measures concerning the definition of economic efficiency of high-speed movement organization taking into account the operating experience of rapid transportations in Ukraine, travel time, number of stops on the route, schedule and the demand for these transportations. Methodology. The economic feasibility for appropriateness of high-speed movement organization in Ukraine is an investment project, which involves step-by-step money investment to the construction. To solve such problems one uses net present value, which UZ or newly created companies can get during the project realization and after its completion. Findings. On the basis of obtained studies one can state that the methodology of complex determination of construction efficiency and high-speed passenger trains operation taking into account the cost of infrastructure, rolling stock, impact of environmental factors, etc. was developed in the article. Originality. We propose a scientific approach to determine the economic efficiency of the construction and high-speed main lines operation. This approach, unlike the existing one, includes the improved principles of determining the passenger traffic, the cost of high-speed mainline construction, the number of rolling stock; optimizes income and expenditure calculations in the context of competitive advantages and impact of the external factors on the company. For the first time it was taken into account the transit flow of passengers departing from CIS countries to the vacation in the Crimea, the Carpathians, Odessa and Lviv regions. The account of these factors increases the feasibility of administrative decisions concerning ensuring the efficiency of high-speed traffic functioning. Practical value. The proposed methodology and the research results allowed determining the construction reasonability of high-speed mainline for the passenger trains with a speed at least250 km/h in

  18. Verification of high-speed solar wind stream forecasts using operational solar wind models

    OpenAIRE

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.; Nikolic, Ljubomir; Vennerstrom, Susanne; Schoengassner, Florian; Hofmeister, Stefan J.

    2016-01-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the ACE spacecraft for ...

  19. Application of artificial neural networks for operating speed prediction at horizontal curves:a case study in Egypt

    Institute of Scientific and Technical Information of China (English)

    Ahmed Mohamed Semeida

    2014-01-01

    Horizontal alignment greatly affects the speed of vehicles at rural roads. Therefore, it is necessary to analyze and predict vehicles speed on curve sections. Numerous studies took rural two-lane as research subjects and provided models for predicting operating speeds. However, less attention has been paid to multi-lane high-ways especially in Egypt. In this research, field operating speed data of both cars and trucks on 78 curve sections of four multi-lane highways is collected. With the data, cor-relation between operating speed (V85) and alignment is analyzed. The paper includes two separate relevant analy-ses. The first analysis uses the regression models to investigate the relationships between V85 as dependent variable, and horizontal alignment and roadway factors as independent variables. This analysis proposes two pre-dicting models for cars and trucks. The second analysis uses the artificial neural networks (ANNs) to explore the previous relationships. It is found that the ANN modeling gives the best prediction model. The most influential var-iable on V85 for cars is the radius of curve. Also, for V85 for trucks, the most influential variable is the median width. Finally, the derived models have statistics within the acceptable regions and they are conceptually reasonable.

  20. 75 FR 25927 - Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations

    Science.gov (United States)

    2010-05-10

    ... From the Federal Register Online via the Government Publishing Office ] Part II Department of Transportation Federal Railroad Administration 49 CFR Parts 213 and 238 Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations; Proposed Rule #0;#0;Federal Register / Vol....

  1. The experimental research of the operating processes in slow speed stages of air reciprocating medium-pressure compressors

    Science.gov (United States)

    Yusha, V. L.; Busarov, S. S.; Goshlya, R. Yu.; Vasiliev, V. K.

    2017-08-01

    To study operating processes of slow speed long-stroke compressors with special structural parameters, a test bench is developed. Experimental dependences of the gas instantaneous parameters in a working chamber and integral characteristics of a stage with intensive cylinder external cooling are obtained.

  2. Verification of high-speed solar wind stream forecasts using operational solar wind models

    Science.gov (United States)

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.; Nikolic, Ljubomir; Vennerstrom, Susanne; Schöngassner, Florian; Hofmeister, Stefan J.

    2016-07-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the Advanced Composition Explorer (ACE) spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near-Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona and the background solar wind conditions. We found that both solar wind models are capable of predicting the large-scale features of the observed solar wind speed (root-mean-square error, RMSE ≈100 km/s) but tend to either overestimate (ESWF) or underestimate (WSA) the number of high-speed solar wind streams (threat score, TS ≈ 0.37). The predicted high-speed streams show typical uncertainties in the arrival time of about 1 day and uncertainties in the speed of about 100 km/s. General advantages and disadvantages of the investigated solar wind models are diagnosed and outlined.

  3. Linearity improvement of high-speed avalanche photodiodes using thin depleted absorber operating with higher order modulation format.

    Science.gov (United States)

    Nada, Masahiro; Hoshi, Takuya; Yamazaki, Hiroshi; Hashimoto, Toshikazu; Matsuzaki, Hideaki

    2015-10-19

    We present an avalanche photodiode (APD) with high-speed, high-responsivity and high-linearity operation to cope with higher order modulation format, such as pulse-amplitude modulation (PAM). A hybrid absorber configuration with thin depleted region which we newly employed successfully eliminates the space charge effect in the APD while maintaining high responsivity and operating speed. The fabricated APD shows an improved optical-input-electrical-output linearity for an optical input power over -8 dBm, and an optical receiver with this APD achieves both an error-free operation with a KP4 FEC and a high sensitivity of -17 dBm against a 28-Gbaud PAM4 signal.

  4. Estimated wind speed feed forward control for wind turbine operation optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Van der Hooft, E.L.; Van Engelen, T.G. [ECN Wind Energy, Petten (Netherlands)

    2004-11-01

    For a pitch controlled variable speed wind turbine, a feed forward control structure based on the estimation of rotor averaged wind speed has been developed and analyzed. The additional control action will accelerate ordinary rotor speed feedback control to resist disturbances of wind speed turbulence and wind gusts. Wind speed estimation is based on reconstruction of aerodynamic torque from measurements and a priori knowledge of rotor behaviour. The theoretical base arises from the energy balance between captured aerodynamic energy from wind on the one hand and extracted electric energy (generator), stored kinetic energy (rotor inertia) and losses on the other hand. A tabular implementation for use in real-time control has been derived and evaluated by time domain simulations, stability analysis and parametric uncertainty studies. Without stability drawbacks, the proposed method has shown to be a powerful for reduction of rotor speed variations (30-40%) and wind gust suppression. Energy yield increase is feasible (0.9%) if temporarily torque excesses are not allowed.

  5. Verification of high-speed solar wind stream forecasts using operational solar wind models

    DEFF Research Database (Denmark)

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.

    2016-01-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate...... high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the Advanced Composition Explorer (ACE) spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation...... between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near-Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona...

  6. Detecting moving objects in an optic flow field using direction- and speed-tuned operators.

    Science.gov (United States)

    Royden, Constance S; Holloway, Michael A

    2014-05-01

    An observer moving through a scene must be able to identify moving objects. Psychophysical results have shown that people can identify moving objects based on the speed or direction of their movement relative to the optic flow field generated by the observer's motion. Here we show that a model that uses speed- and direction-tuned units, whose responses are based on the response properties of cells in the primate visual cortex, can successfully identify the borders of moving objects in a scene through which an observer is moving.

  7. Two-axis hydraulic joint for high speed, heavy lift robotic operations

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, M.R.; Robinett, R.D.; Phelan, J.R.; VanZuiden, D.M.

    1994-04-01

    A hydraulically driven universal joint was developed for a heavy lift, high speed nuclear waste remediation application. Each axis is driven by a simple hydraulic cylinder controlled by a jet pipe servovalve. Servovalve behavior is controlled by a force feedback control system, which damps the hydraulic resonance. A prototype single joint robot was built and tested. A two joint robot is under construction.

  8. Speed regulated drives save energy and operating cost; Drehzahlvariable Antriebe senken Energie- und Betriebskosten

    Energy Technology Data Exchange (ETDEWEB)

    Possberg, Norbert

    2009-12-15

    The cement factory of the Lafarge group at Hope, United Kingdom, retrofitted the last two drive units of the production chain by an electronic speed regulation. By utilization of frequency converters in the cooler ventilation sector the total energy consumption lowered to more than 15 %. (orig./GL)

  9. Robustness of Multiple High Speed TCP CUBIC Connections Under Severe Operating Conditions

    DEFF Research Database (Denmark)

    Pilimon, Artur; Ruepp, Sarah Renée; Berger, Michael Stübert

    2015-01-01

    We study the adaptation capabilities and robustness of the high-speed TCP CUBIC algorithm. For this purpose we consider a network environment with variable and high random packet loss and a large Bandwidth-Delay product, shared by multiple heterogeneous TCP connections. The analysis is based on a...

  10. Results and conclusions: perception sensor study for high speed autonomous operations

    Science.gov (United States)

    Schneider, Anne; LaCelle, Zachary; Lacaze, Alberto; Murphy, Karl; Close, Ryan

    2016-05-01

    Previous research has presented work on sensor requirements, specifications, and testing, to evaluate the feasibility of increasing autonomous vehicle system speeds. Discussions included the theoretical background for determining sensor requirements, and the basic test setup and evaluation criteria for comparing existing and prototype sensor designs. This paper will present and discuss the continuation of this work. In particular, this paper will focus on analyzing the problem via a real-world comparison of various sensor technology testing results, as opposed to previous work that utilized more of a theoretical approach. LADAR/LIDAR, radar, visual, and infrared sensors are considered in this research. Results are evaluated against the theoretical, desired perception specifications. Conclusions for utilizing a suite of perception sensors, to achieve the goal of doubling ground vehicle speeds, is also discussed.

  11. Impact of Wind Speed Correlation on the Operation of Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Davril Mathieu

    2016-01-01

    Full Text Available Renewable resources technologies such as wind power currently demonstrate a worldwide popularity thanks to their environmental friendly status and their economic potential. The variability of the wind power output implies the use of practical solutions such as energy storage systems in order to retain the power system stability and reliability. The wind geographical correlation between different wind farms also impacts the system reliability. This paper studies the effects of the wind speed correlation level on the performance of the associated energy storage system (ESS. Wind correlated model using Weibull probability distribution and Nataf transformation is presented. Energy storage system model and energy management algorithm are developed. Both are applied to a modified IEEE-RTS power generation and load model. The case simulation results indicate that the wind speed correlation level between two wind farms impacts the power distribution inside energy storages and that it needs to be considered in order not to overestimate ESS benefits on the system.

  12. Operating styles, working time and daily driving distance in relation to a taxi driver's speeding offenses in Taiwan.

    Science.gov (United States)

    Tseng, Chien-Ming

    2013-03-01

    This study explored the determinant factors of taxi drivers' speeding violations in Taiwan. Data were gathered from a nation wide survey and included 6923 professional taxi drivers in 2006. The results indicated that 96.6% were males and 92.5% had less than a college level education. Daily working hours were from 2.5 h to 15 h with a mean of 10.12 h. The data also indicated that taxi drivers worked approximately 27.35 days and only took 2.65 days rest per month. Of the observed taxi drivers, 25.6% reported at least one speeding violation in a one-year period. The results of a generalized linear model (GLM) revealed that the determinant factors associating with a taxi driver's speeding violation were not related to gender or educational level. However, age, job experience, operating styles, kilometers driven daily, driving late at night, and monthly off duty days were significantly associated with committing the speeding violations. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. DEVELOPMENT OF NEUROMORPHIC SIFT OPERATOR WITH APPLICATION TO HIGH SPEED IMAGE MATCHING

    Directory of Open Access Journals (Sweden)

    M. Shankayi

    2015-12-01

    Full Text Available There was always a speed/accuracy challenge in photogrammetric mapping process, including feature detection and matching. Most of the researches have improved algorithm's speed with simplifications or software modifications which increase the accuracy of the image matching process. This research tries to improve speed without enhancing the accuracy of the same algorithm using Neuromorphic techniques. In this research we have developed a general design of a Neuromorphic ASIC to handle algorithms such as SIFT. We also have investigated neural assignment in each step of the SIFT algorithm. With a rough estimation based on delay of the used elements including MAC and comparator, we have estimated the resulting chip's performance for 3 scenarios, Full HD movie (Videogrammetry, 24 MP (UAV photogrammetry, and 88 MP image sequence. Our estimations led to approximate 3000 fps for Full HD movie, 250 fps for 24 MP image sequence and 68 fps for 88MP Ultracam image sequence which can be a huge improvement for current photogrammetric processing systems. We also estimated the power consumption of less than10 watts which is not comparable to current workflows.

  14. Verification of high-speed solar wind stream forecasts using operational solar wind models

    CERN Document Server

    Reiss, Martin A; Veronig, Astrid M; Nikolic, Ljubomir; Vennerstrom, Susanne; Schoengassner, Florian; Hofmeister, Stefan J

    2016-01-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the ACE spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near-Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona and the background solar wind conditions. We found that both solar wind models are capable of predicting the large-scale features of the observed sol...

  15. Spindle speed variation technique in turning operations: Modeling and real implementation

    Science.gov (United States)

    Urbikain, G.; Olvera, D.; de Lacalle, L. N. López; Elías-Zúñiga, A.

    2016-11-01

    Chatter is still one of the most challenging problems in machining vibrations. Researchers have focused their efforts to prevent, avoid or reduce chatter vibrations by introducing more accurate predictive physical methods. Among them, the techniques based on varying the rotational speed of the spindle (or SSV, Spindle Speed ​​Variation) have gained great relevance. However, several problems need to be addressed due to technical and practical reasons. On one hand, they can generate harmful overheating of the spindle especially at high speeds. On the other hand, the machine may be unable to perform the interpolation properly. Moreover, it is not trivial to select the most appropriate tuning parameters. This paper conducts a study of the real implementation of the SSV technique in turning systems. First, a stability model based on perturbation theory was developed for simulation purposes. Secondly, the procedure to realistically implement the technique in a conventional turning center was tested and developed. The balance between the improved stability margins and acceptable behavior of the spindle is ensured by energy consumption measurements. Mathematical model shows good agreement with experimental cutting tests.

  16. Advantages of variable-speed operation of hydraulic turbo-engines; Vorteile durch den drehzahlvariablen Betrieb von hydraulischen Stroemungsmaschinen

    Energy Technology Data Exchange (ETDEWEB)

    Harbort, T. [Stuttgart Univ. (Germany). Inst. fuer Stroemungsmechanik und Hydraulische Stroemungsmaschinen

    1997-12-31

    The performance of current hydraulic turbo-engines in the variable speed sector is monitored and judged. The study covers radial and axial engines as well as Pelton turbines. Variable-speed operation of hydraulic turbo-engines can be realized by means of different combinations of electrical rotating machines and frequency converters. The operating range of the frequency converter plays an important role in the optimization of performance and is taken into account. The smoothness of run of reaction turbines and their cavitation performance can be enhanced by speed regulation. But above all, efficiency is more or less substantially enhanced during partial load or in the case of greatly varying heights of drop. The latter holds true also of Pelton turbines. (orig.) [Deutsch] Das Betriebsverhalten der gaengigen hydraulischen Stroemungsmaschinen wird in Hinblick auf den drehzahlvariablen Betrieb erfasst und beurteilt. Die Untersuchung erfolgt fuer Radialmaschinen, Axialmaschinen und Peltonturbinen. Der drehzahlvariable Betrieb hydraulischer Stroemungsmaschinen kann mit verschiedenen Kombinationen von elektrischen Maschinen und Frequenzumrichtern realisiert werden. Der Arbeitsbereich des Frequenzumrichters spielt eine wichtige Rolle fuer die Optimierung des Betriebsverhaltens und wird beruecksichtigt. Bei Ueberdruckturbinen kann man durch Drehzahlregelung eine groessere Laufruhe sowie ein guenstigeres Kavitationsverhalten erreichen. Vor allem aber sind im Teillastbereich oder bei stark schwankenden Fallhoehen mehr oder weniger grosse Wirkungsgradgewinne erzielbar. Das letztere gilt auch fuer Peltonturbinen. (orig.)

  17. Minimum-Voltage Vector Injection Method for Sensorless Control of PMSM for Low-Speed Operations

    DEFF Research Database (Denmark)

    Xie, Ge; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

    2016-01-01

    In this paper, a simple signal injection method is proposed for sensorless control of PMSM at low speed, which ideally requires one voltage vector only for position estimation. The proposed method is easy to implement resulting in low computation burden. No filters are needed for extracting...... may also be further developed to inject two opposite voltage vectors to reduce the effects of inverter voltage error on the position estimation accuracy. The effectiveness of the proposed method is demonstrated by comparing with other sensorless control method. Theoretical analysis and experimental...

  18. Online Load Operating Mode of Oil Film Bearing in High Speed Wire Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    LI Yugui; PANG Siqing; HUANG Qingxue; WANG Jianmei; ZHAO Chunjiang

    2006-01-01

    To study the mechanism of burnt damage of oil film bearing in high-speed wire rolling mill, reasonable temperature sensors are designed and calibrated, pressure block of rolling mill has been transformed into pressure sensors. Online temperature and load of oil film bearing in a domestic precision rolling F15 have been tested. Consequently, a large sum of valuable test data was obtained. The distributions rules of pressure and temperature under continuous online rolling state are recorded in detail. Theoretical and experimental results are beneficial to damage mechanism of oil film bearing, thus its service life could be prolonged. Moreover, such results could provide an important reference for online test and control.

  19. Torque control of synchronous and induction generators for variable speed operation of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Ola; Ulen, E. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

    1996-12-01

    The aim of this paper is to investigate variable speed electrical systems. Synchronous generators with diode rectifiers and line-commutated thyristor converters are compared with induction generators with force commutated transistor converters and scalar control. The system characteristics are examined regarding possible speed of response (bandwidth) of the torque control, including the sensitivity to disturbances for the drive train and also the possibility to get damping of the drive train resonance. Analyses, simulations and laboratory tests with a 40 kW machine set-up have been performed. The investigation shows that the system with synchronous generator is well suited for wind power applications. A rapid standard DC-current regulator is included in the torque control and can be used for damping of the resonance. The torque control has a bandwidth up to about 3 Hz and the DC-voltage controller up to about 1 Hz. The system with induction generator with scalar control (no transformations) is more difficult to control. A linear approach is only possible up to about 1.5 Hz. In this region it turns out that the behaviour can be visualized as an added inertia on the generator side that can be rather big. 4 refs, 9 figs

  20. Twenty First Century Warfare -- Theater Operations at the Speed of Light

    Science.gov (United States)

    2007-11-02

    advised for two reasons. First, certain DEW assets can provide operational fires from outside the AOR. For example, fixed GBL sites located in the United...allocation of DEW operational fires. For example, a commander may elect to use the same GBL weapon to conduct a counterspace mission in the morning, a...other DEW concepts, such as RF weapons and GBL /relay mirror systems. Currently, training and war gaming for DEW systems focuses largely on the practical

  1. Remote operation over low speed, high latency links; Operacao remota confiavel usando circuitos de baixa velocidade e alta latencia

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Marcelo D.; Nunes, Ildemar P. [Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Remote Control and monitoring of a compressor station with more than 3000 tags can be a hard task to accomplish over a low speed satellite link. This paper presents Datasync, an application specially developed to provide acceptable performance levels over a VSAT link. One of its main features is to enable the establishment of communication dead bands. The dead bands can be altered while the application is running (no restart is needed), so that the operator is able to increase a specific tag's dead band immediately after detecting that it is reporting too many exceptions, which would cause an increase on the traffic and response times. (author)

  2. Speed-variable Switched Differential Pump System for Direct Operation of Hydraulic Cylinders

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Roemer, Daniel Beck; Pedersen, Henrik Clemmensen;

    2015-01-01

    Efforts to overcome the inherent loss of energy due to throttling in valve driven hydraulic systems are many, and various approaches have been proposed by research communities as well as the industry. Recently, a so-called speed-variable differential pump was proposed for direct drive of hydraulic...... differential cylinders. The main idea was here to utilize an electric rotary drive, with the shaft interconnected to two antiparallel fixed displacement gear pumps, to actuate a differential cylinder. With the design carried out such that the area ratio of the cylinder matches the displacement ratio of the two...... gear pumps, the throttling losses are confined to cross port leakage in the cylinder and leakage of the pumps. However, it turns out that the volumetric pump losses and the pressure dynamics of the cylinder and connecting pipes may cause pressure increase- or decrease in the cylinder chambers, which...

  3. Fifteen Years of Operation at NASA's National Transonic Facility with the World's Largest Adjustable Speed Drive

    Science.gov (United States)

    Sydnor, George H.; Bhatia, Ram; Krattiger, Hansueli; Mylius, Justus; Schafer, D.

    2012-01-01

    In September 1995, a project was initiated to replace the existing drive line at NASA's most unique transonic wind tunnel, the National Transonic Facility (NTF), with a single 101 MW synchronous motor driven by a Load Commutated Inverter (LCI). This Adjustable Speed Drive (ASD) system also included a custom four-winding transformer, harmonic filter, exciter, switch gear, control system, and feeder cable. The complete system requirements and design details have previously been presented and published [1], as well as the commissioning and acceptance test results [2]. The NTF was returned to service in December 1997 with the new drive system powering the fan. Today, this installation still represents the world s largest horizontal single motor/drive combination. This paper describes some significant events that occurred with the drive system during the first 15 years of service. These noteworthy issues are analyzed and root causes presented. Improvements that have substantially increased the long term viability of the system are given.

  4. Preload-based starling-like control for rotary blood pumps: numerical comparison with pulsatility control and constant speed operation.

    Directory of Open Access Journals (Sweden)

    Mahdi Mansouri

    Full Text Available In this study, we evaluate a preload-based Starling-like controller for implantable rotary blood pumps (IRBPs using left ventricular end-diastolic pressure (PLVED as the feedback variable. Simulations are conducted using a validated mathematical model. The controller emulates the response of the natural left ventricle (LV to changes in PLVED. We report the performance of the preload-based Starling-like controller in comparison with our recently designed pulsatility controller and constant speed operation. In handling the transition from a baseline state to test states, which include vigorous exercise, blood loss and a major reduction in the LV contractility (LVC, the preload controller outperformed pulsatility control and constant speed operation in all three test scenarios. In exercise, preload-control achieved an increase of 54% in mean pump flow ([Formula: see text] with minimum loading on the LV, while pulsatility control achieved only a 5% increase in flow and a decrease in mean pump speed. In a hemorrhage scenario, the preload control maintained the greatest safety margin against LV suction. PLVED for the preload controller was 4.9 mmHg, compared with 0.4 mmHg for the pulsatility controller and 0.2 mmHg for the constant speed mode. This was associated with an adequate mean arterial pressure (MAP of 84 mmHg. In transition to low LVC, [Formula: see text] for preload control remained constant at 5.22 L/min with a PLVED of 8.0 mmHg. With regards to pulsatility control, [Formula: see text] fell to the nonviable level of 2.4 L/min with an associated PLVED of 16 mmHg and a MAP of 55 mmHg. Consequently, pulsatility control was deemed inferior to constant speed mode with a PLVED of 11 mmHg and a [Formula: see text] of 5.13 L/min in low LVC scenario. We conclude that pulsatility control imposes a danger to the patient in the severely reduced LVC scenario, which can be overcome by using a preload-based Starling-like control approach.

  5. BEGA Starter/Alternator—Vector Control Implementation and Performance for Wide Speed Range at Unity Power Factor Operation

    DEFF Research Database (Denmark)

    Boldea, Ion; Coroban-Schramel, Vasile; Andreescu, Gheorghe-Daniel

    2010-01-01

    The Biaxial Excitation Generator for Automobiles (BEGA) is proposed as a solution for integrated starter/alternator systems used in hybrid electric vehicles. This paper demonstrates through experiments and simulations that BEGA has a very large constant power speed range. A vector control structure...... is proposed for BEGA operation during motoring and generating, at unity power factor with zero d-axis current (id) and zero q-axis flux (Ψq) control. In such conditions, BEGA behaves like a separately excited dc brush(commutator) machine, in the sense that no stator inductance voltage drop occurs...... in such constraint control conditions. A high iq current is required in order to cancel the q-axis flux, during unity power factor operation. This engages higher copper losses in the machine under light load. In order to minimize the copper losses, for lower load levels, a current referencer is proposed. Due...

  6. The Design and Operation of a Simple Low-Speed Flutter-Suppression Model.

    Science.gov (United States)

    1984-04-01

    Library Flying Operations and Airworthiness Division Statutory and State Authorities and Industry Trans-Australia Airlines, Library Qantas Airways ...detailed mathematical analysis , a small dynamic flutter model has been designed and tested, in order to explore the problems of instrument- ation and...Henry A. Cole Jnr. - NASA CR-2205 March 1973 2. Adaptive Flutter Suppression - Analysis and Test. Johnson, E.H., - AGARD-R-703 Harvey, C.A., January

  7. Design and Characterization of two stage High-Speed CMOS Operational Amplifier

    Directory of Open Access Journals (Sweden)

    Rahul Chaudhari

    2014-03-01

    Full Text Available A method described in this paper is to design a Two Stage CMOS operational amplifier and analyze the effect of various aspect ratios on the characteristics of this Op-Amp, which operates at 1.8V power supply using tsmc 0.18μm CMOS technology. In this paper trade-off curves are computed between all characteristics such as Gain, PM, GBW, ICMRR, CMRR, Slew Rate etc. The OPAMP designed is a two-stage CMOS OPAMP. The OPAMP is designed to exhibit a unity gain frequency of 14MHz and exhibits a gain of 59.98dB with a 61.235 phase margin. Design has been carried out in Mentor graphics tools. Simulation results are verified using Model Sim Eldo and Design Architect IC. The task of CMOS operational amplifiers (Op-Amps design optimization is investigated in this work. This Paper focused on the optimization of various aspect ratios, which gave the result of different parameter. When this task is analyzed as a search problem, it can be translated into a multi-objective optimization application in which various Op-Amps’ specifications have to be taken into account, i.e., Gain, GBW (gain-bandwidth product, phase margin and others. The results are compared with respect to standard characteristics of the op-amp with the help of graph and table. Simulation results agree with theoretical predictions. Simulations confirm that the settling time can be further improved by increasing the value of GBW, the settling time is achieved 19ns. It has been demonstrated that when W/L increases the parameters GBW increases and settling time reduces.

  8. Six-step Voltage Control of PM Brushless AC Motors under High Speed Flux-weakening Operation for EV/HEV Applications

    Institute of Scientific and Technical Information of China (English)

    诸自强

    2008-01-01

    The torque-speed characteristics of brushless motor having an interior permanent magnet rotor and a sinusoidalback-emf waveform are compared experimentally when it is operated in brushless AC (BLAC) mode and brushless DC(BLDC) modes with both 2-phase, 120° conduction (BLDC-120) and 3-phase,180° conduction (BLDC-180).Particularemphasis is on high-speed,six-step voltage controlled,flux-weakening operation.h is shown that for EV/HEV applications,even for interior PM brushless motors which have sinusoidal back-emf waveforms,in order to achieve maximum torque perampere capability over wide operation speed range,it is advantageous to employ a hybrid operation mode-BLAC operationin the constant torque region and six-step voltage control (BLDC-180 operation, together with current phase control) inthe flux-weakening region.

  9. Speed-variable Switched Differential Pump System for Direct Operation of Hydraulic Cylinders

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Roemer, Daniel Beck; Pedersen, Henrik Clemmensen

    2015-01-01

    proportional valves, this design allows to control the lower chamber pressure levels, throttling excess compression flow to tank. The resulting design introduces additional losses due to throttling of excess compression flow, but also improves the dynamic properties of the system significantly. The proposed...... differential cylinders. The main idea was here to utilize an electric rotary drive, with the shaft interconnected to two antiparallel fixed displacement gear pumps, to actuate a differential cylinder. With the design carried out such that the area ratio of the cylinder matches the displacement ratio of the two...... may seriously influence the dynamics and hence the performance during operation. This paper presents an analysis of these properties, and a redesign of the hydraulic system concept is proposed. Here the area- and displacement ratios are deliberately mismatched, causing inherent pressure build...

  10. Simulation model of a variable-speed pumped-storage power plant in unstable operating conditions in pumping mode

    Science.gov (United States)

    Martínez-Lucas, G.; Pérez-Díaz, J. I.; Sarasúa, J. I.; Cavazzini, G.; Pavesi, G.; Ardizzon, G.

    2017-04-01

    This paper presents a dynamic simulation model of a laboratory-scale pumped-storage power plant (PSPP) operating in pumping mode with variable speed. The model considers the dynamic behavior of the conduits by means of an elastic water column approach, and synthetically generates both pressure and torque pulsations that reproduce the operation of the hydraulic machine in its instability region. The pressure and torque pulsations are generated each from a different set of sinusoidal functions. These functions were calibrated from the results of a CFD model, which was in turn validated from experimental data. Simulation model results match the numerical results of the CFD model with reasonable accuracy. The pump-turbine model (the functions used to generate pressure and torque pulsations inclusive) was up-scaled by hydraulic similarity according to the design parameters of a real PSPP and included in a dynamic simulation model of the said PSPP. Preliminary conclusions on the impact of unstable operation conditions on the penstock fatigue were obtained by means of a Monte Carlo simulation-based fatigue analysis.

  11. Binary CMOS image sensor with a gate/body-tied MOSFET-type photodetector for high-speed operation

    Science.gov (United States)

    Choi, Byoung-Soo; Jo, Sung-Hyun; Bae, Myunghan; Kim, Sang-Hwan; Shin, Jang-Kyoo

    2016-05-01

    In this paper, a binary complementary metal oxide semiconductor (CMOS) image sensor with a gate/body-tied (GBT) metal oxide semiconductor field effect transistor (MOSFET)-type photodetector is presented. The sensitivity of the GBT MOSFET-type photodetector, which was fabricated using the standard CMOS 0.35-μm process, is higher than the sensitivity of the p-n junction photodiode, because the output signal of the photodetector is amplified by the MOSFET. A binary image sensor becomes more efficient when using this photodetector. Lower power consumptions and higher speeds of operation are possible, compared to the conventional image sensors using multi-bit analog to digital converters (ADCs). The frame rate of the proposed image sensor is over 2000 frames per second, which is higher than those of the conventional CMOS image sensors. The output signal of an active pixel sensor is applied to a comparator and compared with a reference level. The 1-bit output data of the binary process is determined by this level. To obtain a video signal, the 1-bit output data is stored in the memory and is read out by horizontal scanning. The proposed chip is composed of a GBT pixel array (144 × 100), binary-process circuit, vertical scanner, horizontal scanner, and readout circuit. The operation mode can be selected from between binary mode and multi-bit mode.

  12. INCREASE THE RESOURCE OF CURRENT COLLECTOR ELEMENTS OF THE ELECTRIFIED HIGH-SPEED TRANSPORT IN OPERATING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Y. L. Bolshakov

    2015-07-01

    Full Text Available Purpose. The paper is aimed to determinate the main ways of increasing resource efficiency and exploitation of coal current collector surface inserts of speed electric rolling stock. Methodology. The research is based on the technique relies on the use of theory regulations of technical systems reliability, electromechanical processes, theory of statistics. Findings. The existing approaches to the production of current collector surface inserts in Europe and Ukraine were considered, a number of information sources was analyzed. The most effective ways of increasing current carrying capacity and wear resistance of current collector elements were determined. It has been established that the existing system for determining the quality of manufacturing of current collector elements have a number of drawbacks that make it difficult to control the input and makes diagnosing current collecting elements in operation impossible. On the basis of the facts, for the needs of the locomotive depot, we propose a new booth allowing avoiding the existing difficulties with diagnosing of current collector elements. During the study were established pervasive transgressions of technological standards of service pantographs. Originality. Based on the results of operational research carried out on the basis of the locomotive depot, obtained depending, based on which, it is proposed to introduce an operative diagnosing system of the current collector elements state during operation. In the course of a comparative analysis of existing and perspective development directions of current collector elements with high load current carrying capacity and durability, were definited constructive conditions for the optimal ratio is inserts. It was established that a significant proportion of failures occur due to imperfect maintenance system for which, on the basis of operational data, recommendations were developed. Practical value. Obtained results of the information sources

  13. Validation of Generic Models for Variable Speed Operation Wind Turbines Following the Recent Guidelines Issued by IEC 61400-27

    Directory of Open Access Journals (Sweden)

    Andrés Honrubia-Escribano

    2016-12-01

    Full Text Available Considerable efforts are currently being made by several international working groups focused on the development of generic, also known as simplified or standard, wind turbine models for power system stability studies. In this sense, the first edition of International Electrotechnical Commission (IEC 61400-27-1, which defines generic dynamic simulation models for wind turbines, was published in February 2015. Nevertheless, the correlations of the IEC generic models with respect to specific wind turbine manufacturer models are required by the wind power industry to validate the accuracy and corresponding usability of these standard models. The present work conducts the validation of the two topologies of variable speed wind turbines that present not only the largest market share, but also the most technological advances. Specifically, the doubly-fed induction machine and the full-scale converter (FSC topology are modeled based on the IEC 61400-27-1 guidelines. The models are simulated for a wide range of voltage dips with different characteristics and wind turbine operating conditions. The simulated response of the IEC generic model is compared to the corresponding simplified model of a wind turbine manufacturer, showing a good correlation in most cases. Validation error sources are analyzed in detail, as well. In addition, this paper reviews in detail the previous work done in this field. Results suggest that wind turbine manufacturers are able to adjust the IEC generic models to represent the behavior of their specific wind turbines for power system stability analysis.

  14. Results of an Advanced Fan Stage Operating Over a Wide Range of Speed and Bypass Ratio. Part 1; Fan Stage Design and Experimental Results

    Science.gov (United States)

    Suder, Kenneth L.; Prahst, Patricia S.; Thorp, Scott A.

    2011-01-01

    NASA s Fundamental Aeronautics Program is investigating turbine-based combined cycle (TBCC) propulsion systems for access to space because it provides the potential for aircraft-like, space-launch operations that may significantly reduce launch costs and improve safety. To this end, National Aeronautics and Space Administration (NASA) and General Electric (GE) teamed to design a Mach 4 variable cycle turbofan/ramjet engine for access to space. To enable the wide operating range of a Mach 4+ variable cycle turbofan ramjet required the development of a unique fan stage design capable of multi-point operation to accommodate variations in bypass ratio (10 ), fan speed (7 ), inlet mass flow (3.5 ), inlet pressure (8 ), and inlet temperature (3 ). In this paper, NASA has set out to characterize a TBCC engine fan stage aerodynamic performance and stability limits over a wide operating range including power-on and hypersonic-unique "windmill" operation. Herein, we will present the fan stage design, and the experimental test results of the fan stage operating from 15 to 100 percent corrected design speed. Whereas, in the companion paper, we will provide an assessment of NASA s APNASA code s ability to predict the fan stage performance and operability over a wide range of speed and bypass ratio.

  15. Mathematical modeling of MSW combustion and SNCR in a full-scale municipal incinerator and effects of grate speed and oxygen-enriched atmospheres on operating conditions.

    Science.gov (United States)

    Liang, Zengying; Ma, Xiaoqian

    2010-12-01

    The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathematical modeling and accurate prediction of pollutant emissions. In this paper, mathematical modeling methods for both solid and gaseous phases were employed to simulate the operation of a 450 t/d MSW-burning incinerator to obtain detailed information on the flow and combustion characteristics in the furnace and to predict the amount of pollutant emissions. The predicted data were compared to on-site measurements of gas temperature, gas composition and SNCR de-NO(X) system. The major operating conditions considered in this paper were grate speed and oxygen concentration. A suitable grate speed ensures complete waste combustion. The predictions are as follows: volatile release increases with increasing grate speed, and the maximal value is within the range of 700-800 kg/m(2)h; slow grate speeds result in incomplete combustion of fixed carbon; the gas temperature at slow grate speeds is higher due to adequate oxygenation for fixed carbon combustion, and the deviation reaches 200K; NO(X) emission decreases, but CO emission and O(2) concentrations increase, and the deviation is 63%, 34% and 35%, respectively. Oxygen-enriched atmospheres promote the destruction of most pollutants due to the high oxygen partial pressure and temperature. The furnace temperature, NO production and CO emission increase as the oxygen concentration increases, and the deviation of furnace exit temperature, NO and CO concentration is 38.26%, 58.43% and 86.67%, respectively. Finally, oxygen concentration is limited to below 35% to prevent excessive CO and NO(X) emission without compromising plant performance. The current work greatly helps to understand the operating characteristics of large-scale MSW-burning plants. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Results of an Advanced Fan Stage Operating Over a Wide Range of Speed and Bypass Ratio. Part 2; Comparison of CFD and Experimental Results

    Science.gov (United States)

    Celestina, Mark L.; Suder, Kenneth L.; Kulkarni, Sameer

    2010-01-01

    NASA and GE teamed to design and build a 57 percent engine scaled fan stage for a Mach 4 variable cycle turbofan/ramjet engine for access to space with multipoint operations. This fan stage was tested in NASA's transonic compressor facility. The objectives of this test were to assess the aerodynamic and aero mechanic performance and operability characteristics of the fan stage over the entire range of engine operation including: 1) sea level static take-off; 2) transition over large swings in fan bypass ratio; 3) transition from turbofan to ramjet; and 4) fan wind-milling operation at high Mach flight conditions. This paper will focus on an assessment of APNASA, a multistage turbomachinery analysis code developed by NASA, to predict the fan stage performance and operability over a wide range of speeds (37 to 100 percent) and bypass ratios.

  17. Kidney shear wave speed values in subjects with and without renal pathology and inter-operator reproducibility of acoustic radiation force impulse elastography (ARFI--preliminary results.

    Directory of Open Access Journals (Sweden)

    Flaviu Bob

    Full Text Available to assess the inter-operator reproducibility of kidney shear wave speed, evaluated by means of Acoustic Radiation Force Impulse (ARFI elastography, and the factors which influence it.Our prospective pilot study included 107 subjects with or without kidney pathology in which kidney shear wave speed was evaluated by means of ARFI elastography. Intraclass correlation coefficient (ICC was used to assess ARFI elastography reproducibility.A strong agreement was obtained between kidney shear wave speed measurements obtained by the two operators: ICC = 0.71 (right kidney and 0.69 (left kidney. Smaller ICCs were obtained in "healthy subjects", as compared to patients with kidney diseases (0.68 vs. 0.75, in women as compared with men (0.59 vs. 0.78, in subjects younger than 50 years as compared with those aged at least 50 years (0.63 vs. 0.71, in obese as compared with normal weight and overweight subjects (0.36 vs. 0.66 and 0.78 and in case of measurements depth 6 cm as compared with those performed at a depth of 4-6 cm from the skin (0.32 and 0.60 vs. 0.81.ARFI elastography is a reproducible method for kidney shear wave speed assessment.

  18. High-Speed and Low-Energy Flip-Flop Operation of Asymmetric Active-Multimode Interferometer Bi-Stable Laser Diodes

    DEFF Research Database (Denmark)

    Jiang, Haisong; Chaen, Yutaka; Hagio, Takuma;

    2011-01-01

    High-speed (121/25 ps rise/fall time) and low-switching energy (7.1 and 3.4 fJ) alloptical flip-flop operation of single-wavelength high-mesa asymmetric active-MMI bi-stable laser diodes is demonstrated for the first time using 25 ps long switching pulses.......High-speed (121/25 ps rise/fall time) and low-switching energy (7.1 and 3.4 fJ) alloptical flip-flop operation of single-wavelength high-mesa asymmetric active-MMI bi-stable laser diodes is demonstrated for the first time using 25 ps long switching pulses....

  19. Experimental study on the effect of varying syngas composition on the emissions of dual fuel CI engine operating at various engine speeds

    Science.gov (United States)

    Mahgoub, B. K. M.; Sulaiman, S. A.; Karim, Z. A. A.; Hagos, F. Y.

    2015-12-01

    Using syngas as a supplement fuel of diesel in dual fuel mode is a proposed solution in the effort to protect the environment and control the serious threats posed by greenhouse gas emissions from compression ignition engines. The objective of this study was to experimentally examine the effect of syngas composition on the exhaust emission of dual fuel compression ignition (CI) engine at various engine speeds, and to compare the operating ranges of imitated syngas versus pure diesel. The study was conducted using a naturally aspirated, two strokes, single cylinder 3.7 kW diesel engine operated at speeds of 1200, 2000 and 3000 rpm. The engine was tested with three different syngas compositions. Diesel fuel was partially substituted by syngas through the air inlet. The test results disclose the impact of using syngas in CI engines on emission of CO2, NOx, unburned hydrocarbons and carbon monoxide. The experimental measurements confirmed that all syngas compositions are capable of reducing the emissions of CO2 and NOX compared with diesel fuel. Wide range of diesel replacement ratios (up to 72%) was attained without any penalty. Syngas with composition of 49% N2, 12% CO2, 25% CO, 10% H2, and 4% CH4 reduced the emissions of CO2 and NOx at engine speed of 1200 rpm up to 1% and 108 ppm, respectively. The lowest emission of UHC and NOx was emitted when the engine was operating at speed of 2000 rpm and 3000 rpm, respectively with composition of 38% N2, 8% Co2, 29% CO, 19% H2, and 6% CH4. Therefore, syngas could be a promising technique for controlling NOx emissions in CI engines. However, hydrogen content in syngas is important parameter that needs to be further investigation for its effect.

  20. Foil bearings for axial and radial support of high speed rotors: Design, development, and determination of operating characteristics

    Science.gov (United States)

    Licht, L.

    1978-01-01

    Flexible surface thrust and journal foil bearings were fabricated, and their performance was demonstrated, both individually and jointly as a unified rotor support system. Experimental results are documented with graphs and oscilloscopic data of trajectories, waveforms, and scans of amplitude response. At speeds of 40,000 to 45,000 rpm and a mean clearance of the order of 15 to 20 micrometers (600 to 800 micrometers, the resilient, air lubricated, spiral groove thrust bearings support a load of 127 N (29 lb; 13 kgf), equivalent to 3.0 N/sq cm (4.5 lb/sq in 0.31 kgf sq cm). Journal bearings with polygonal sections provided stable and highly damped supports at speeds up to 50,000 rpm.

  1. Kinematic Operating Modes of Two-Speed Two-Carrier Planetary Gear Trains with Four External Shafts

    OpenAIRE

    Troha, Sanjin; Žigulić, Roberto; Karaivanov, Dimitar

    2014-01-01

    Two-speed planetary gear trains with four external shafts, composed of two simple planetary gear trains, are considered in this paper. The labelling system of these trains is defined and all possible variants are determined. Planetary gear trains are divided into three different design groups, and characteristics of trains of each group are given. Possible power flows through the train at both gears for every group are described. An example of determining the function of transmission ratios o...

  2. STUDY REGARDING THE OPERATING SPEED OF FORAGE HARVESTING MACHINERY IN ORDER TO OPTIMIZE THE WORKING CAPACITY AND FUEL CONSUME

    OpenAIRE

    V. MOISE

    2013-01-01

    The efficiency of forage production machinery system is partially reflected in someclassical economical indices, because the real efficiency of mechanical tillageutilization at forage harvesting and preparation must be reflected in the foragequality increasing and feed superior valorization by the farm livestock. An area of7.8 alfalfa ha was harvested with U-650M tractor and ROTO 165 rotary mower andwith U-650M tractor and Zakaz rotary mower at different speeds in field work.Average values of...

  3. THE CHARACTERISTICS OF THE OPERATING PARAMETERS OF THE VERTICAL AXIS WIND TURBINE FOR THE SELECTED WIND SPEED

    Directory of Open Access Journals (Sweden)

    Zbigniew Czyż

    2017-03-01

    Full Text Available The article presents the results of examining a wind turbine on the vertical axis of rotation. The study was conducted in an open circuit wind tunnel Gunt HM 170 in the laboratory of the Department of Thermodynamics, Fluid Mechanics and Aviation Propulsion Systems in Lublin University of Technology. The subject of research was a rotor based on the patent PL 219985. The research object in the form of rotor consists of blades capable of altering the surface of the active area (receiving kinetic energy of the wind. The study was performed on appropriately scaled and geometrically similar models with maintaining, relevant to the type of research, the criterion numbers. Research objects in the form of rotors with different angles of divergence of blades were made using a 3D powder printer ZPrinter® 450. The results of the research conducted were carried out at the selected flow velocity of 6.5 m/s for three angles of divergence, ie. 30°, 60°, and 90° at variable rotational speed. The applied research station allows braking of the turbine to the required speed, recording velocity and torque, which allows to obtain characteristics of torque and power as a function of rotor speed.

  4. STUDY REGARDING THE OPERATING SPEED OF FORAGE HARVESTING MACHINERY IN ORDER TO OPTIMIZE THE WORKING CAPACITY AND FUEL CONSUME

    Directory of Open Access Journals (Sweden)

    V. MOISE

    2013-12-01

    Full Text Available The efficiency of forage production machinery system is partially reflected in someclassical economical indices, because the real efficiency of mechanical tillageutilization at forage harvesting and preparation must be reflected in the foragequality increasing and feed superior valorization by the farm livestock. An area of7.8 alfalfa ha was harvested with U-650M tractor and ROTO 165 rotary mower andwith U-650M tractor and Zakaz rotary mower at different speeds in field work.Average values of the speed in parcel work, work effective capacity, work capacityduring shift, specific work capacity on cutter width, fuel consume per land unit, andspecific fuel consume per mass unit were determined for each speed in field work.Power matching between the tractor and the mower do not always meet therequirements when forming harvesting mechanized systems. Classical mowers withcommon cutting units do not sufficiently load the U-650M tractor existing inmany Romanian farms, which determines an unfavorable functioning regime ofthe tractor engine correlated with increased fuel consumes.

  5. Design and analysis of various multifunctional operations at ultrahigh speed by using a semiconductor optical amplifier-Mach-Zehnder interferometer

    Science.gov (United States)

    Lovkesh; Marwaha, Anupma

    2016-03-01

    Various multifunctional operations are performed by proposing designs of optical adder, subtractor, comparator, and decoder at 60 Gb/s. In all operations, constructive interference is produced by choosing optimized parameters, i.e., optical pulse generator power, input power, semiconductor optical amplifier-Mach-Zehnder interferometer parameters, and so on, for delivering a true output signal. An optical pulse-generated signal is required for all operations except addition, subtraction and equal to in a comparator.

  6. The ALMA high speed optical communication link is here: an essential component for reliable present and future operations

    Science.gov (United States)

    Filippi, G.; Ibsen, J.; Jaque, S.; Liello, F.; Ovando, N.; Astudillo, A.; Parra, J.; Saldias, Christian

    2016-07-01

    Announced in 2012, started in 2013 and completed in 2015, the ALMA high bandwidth communication system has become a key factor to achieve the operational and scientific goals of ALMA. This paper summarizes the technical, organizational, and operational goals of the ALMA Optical Link Project, focused in the creation and operation of an effective and sustainable communication infrastructure to connect the ALMA Operations Support Facility and Array Operations Site, both located in the Atacama Desert in the Northern region of Chile, with the point of presence of REUNA in Antofagasta, about 400km away, and from there to the Santiago Central Office in the Chilean capital through the optical infrastructure created by the EC-funded EVALSO project and now an integral part of the REUNA backbone. This new infrastructure completed in 2014 and now operated on behalf of ALMA by REUNA, the Chilean National Research and Education Network, uses state of the art technologies, like dark fiber from newly built cables and DWDM transmission, allowing extending the reach of high capacity communication to the remote region where the Observatory is located. The paper also reports on the results obtained during the first year and a half testing and operation period, where different operational set ups have been experienced for data transfer, remote collaboration, etc. Finally, the authors will present a forward look of the impact of it to both the future scientific development of the Chajnantor Plateau, where many installations area are (and will be) located, as well as the potential Chilean scientific backbone long term development.

  7. Stack optimization of oxide-based RRAM for fast write speed (<1 μs) at low operating current (<10 μA)

    Science.gov (United States)

    Chen, C. Y.; Goux, L.; Fantini, A.; Degraeve, R.; Redolfi, A.; Groeseneken, G.; Jurczak, M.

    2016-11-01

    In this paper we engineer a TiN ⧹ Al2O3 ⧹ (Hf,Al)O2 ⧹ Ta2O5 ⧹ Hf Oxide Resistive Random Access Memory (OxRRAM) device for fast switching at low operation current without sacrificing the retention and endurance properties. The integrated 40 nm × 40 nm cell switches at 10 μA using write pulses shorter than 100 ns (resp. 1 μs) for Reset (resp. Set) and with amplitude speed by more than 1 decade compared to state-of-the-art OxRRAM stacks at same current level.

  8. BEGA Starter/Alternator - Vector Control Implementation and Performance for Wide Speed Range at Unity Power Factor Operation

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Boldea, Ion; Coroban-Schramel, Vasile

    2008-01-01

    to infinite. A vector control structure is proposed for BEGA operation during motoring and generating, at unity power factor with zero d-axis current (id) and zero q-axis flux (Ψq) control. In such conditions BEGA behaves like a truly dc. brush machine (with zero reactance in steady state !). A high iq...... current is required in order to cancel the q-axis flux, during unity power factor operation. This engages higher copper losses in the machine. In order to minimize the copper losses, for lower load levels, a current referencer is proposed. Due to higher dc field excitation time constant, the dc field...

  9. Observer-based scheme for tuning the control of variable speed wind turbines operating in hostile environments

    DEFF Research Database (Denmark)

    Caruana, Cedric; Al-Durra, Ahmed; Blaabjerg, Frede

    2016-01-01

    the control law. The proposed observer identifies variations in the power coefficient surface over time due to the effect of the environment on the rotor blades. Simulations for both open- and closed-loop operations are shown. The proposed technique shows the potential to alleviate the performance degradation...

  10. 大型低风速风电场运行分析%An Analysis of Large Low-speed Wind Farm Operation

    Institute of Scientific and Technical Information of China (English)

    张小雷; 高崇伦; 吴爱国

    2013-01-01

      近年来,风能资源丰富的区域受到资源和规模等因素的限制,人们悄然把目光转向更为广阔的低风速区域。安徽来安低风速风电场是全国首个低风速风电场。本文介绍了来安风电场的基本情况,从海拔高度对发电量的影响、森林(粗糙度)对发电量的影响、风切变和湍流强度对功率曲线的影响等四个方面分析风电场的运行情况,总结了低风速风电场运行的特点和部分规律,为以后风电场建设提供参考。%In recent years, the development of wind areas with rich wind resource gradually is limited by the resources and the scale of wind farm. People turned to explore broad low-speed wind area.The low-speed wind farm of Lai'an is the frst one in China.The paper introduced the main situation of the Lai'an wind farm. According to comparison of the impact of altitude and forest(roughness) for power generation, the impact of wind shear and turbulence intensity for the power curve, this paper analyzed the operating conditions of the wind farm and summed up the characteristics and regularities of low-speed wind farm operation. It aims to provide reference for the future construction of the wind farm.

  11. EAM-based high-speed 100-km OFDM transmission featuring tolerant modulator operation enabled using SSII cancellation.

    Science.gov (United States)

    Chen, Hsing-Yu; Wei, Chia-Chien; Lu, I-Cheng; Chen, Yu-Chao; Chu, Hsuan-Hao; Chen, Jyehong

    2014-06-16

    In this study, a technique was developed to compensate for nonlinear distortion through cancelling subcarrier-to-subcarrier intermixing interference (SSII) in an electroabsorption modulator (EAM)-based orthogonal frequency-division multiplexing (OFDM) transmission system. The nonlinear distortion to be compensated for is induced by both EAM nonlinearity and fiber dispersion. Because an OFDM signal features an inherently high peak-to-average power ratio, a trade-off exists between the optical modulation index (OMI) and modulator nonlinearity. Therefore, the nonlinear distortion limits the operational tolerance of the bias voltage and the driving power to a small region. After applying the proposed SSII cancellation, the OMI of an OFDM signal was increased yielding only a small increment of nonlinear distortion, and the tolerance region of the operational conditions was also increased. By employing the proposed scheme, this study successfully demonstrates 50-Gbps OFDM transmission over 100-km dispersion-uncompensated single-mode fiber based on a single 10-GHz EAM.

  12. Computer data processing operation speed influencing factors%计算机数据处理的运算速度影响因素探讨

    Institute of Scientific and Technical Information of China (English)

    吕睿

    2015-01-01

    In view of the current speed of the computer data processing is difficult to meet people's growing entertainment and office demand, restricts the development and progress of computer technology, this paper made a brief analysis of the basic concepts of computer data processing, clear focus its data processing features, combined with the computer data processing of the professional theory, the influence of the operation speed of the computer data processing with the factors, including the central processing unit, computer, computer hard drives, memory, etc., it is concluded that the central processing unit (CPU), computer memory, computer hard disk is the main factors influencing the speed of computer data processing, suggested comprehensive optimization, in order to improve the operation speed of computer data processing.%针对当前计算机数据处理的运算速度难以满足人们日渐增长的娱乐与办公需求,制约着计算机技术的发展与进步,本文通过对计算机数据处理的基本概念进行简要的分析,重点明确其数据处理特征,结合计算机数据处理的专业理论,深入剖析计算机数据处理的运算速度的影响因素,包括中央处理器、计算机内存、计算机硬盘等方面,得出了中央处理器、计算机内存、计算机硬盘是影响计算机数据处理的运算速度的主要因素的结论,建议全面优化,以提高计算机数据处理的运算速度。

  13. Study and implementation high speed operating of induced magnetization machines; Etude et mise en oeuvre de machines a aimantation induite fonctionnant a haute vitesse

    Energy Technology Data Exchange (ETDEWEB)

    Alhassoun, Y.

    2005-05-15

    Actually, electromechanical machines are characterized by their low cost and reduced maintenance. Therefore, new types of magnetic materials such as soft magnetic composites (SMC), have to be considered not only for multiple applications (small motors for automotive) for cost reduction, but also when considering other special requirements such as high speed drive (aircraft and space applications). Our report of thesis is articulated around four chapters: The first chapter show the various types of magnetic interactions used in the electromagnetic actuators. The second chapter is devoted to the modelling of the induced magnetic machines by analytical resolution of equations of the field in two dimensions. The third chapter presents the four configurations prototypes of switched reluctance machine which mix the exploitation of laminated materials and the soft magnetic powders. The fourth chapter discusses the critical conditions of this machines operating at high speed. We conclude, insisting on the efforts carried out in term of analytical modelling of the induced magnetization machines for their dimensions and exploited in this same structure, the soft magnetic composite materials. The results show the potential of soft magnetic powders when considering in particular the high frequency losses and their ability to favour the heat dissipation in this structure. (author)

  14. A High-Performance Operational Amplifier for High-Speed High-Accuracy Switch-Capacitor Cells

    Institute of Scientific and Technical Information of China (English)

    Qi Fan; Ning Ning; Qi Yu; Da Chen

    2007-01-01

    A highspeed highaccuracy fully differenttial operational amplifier (opamp) is realized based on noMillercapacitor feedforward (NMCF) compensation scheme. In order to achieve a good phase margin, the NMCF compensation scheme uses the positive phase shift of lefthalfplane (LHP) zero caused by the feedforward path to counteract the negative phase shift of the nondominant pole. Compared to traditional Miller compensation method, the opamp obtains high gain and wide band synchronously without the polesplitting effect while saves significant chip area due to the absence of the Miller capacitor. Simulated by the 0.35 μm CMOS RF technology, the result shows that the openloop gain of the opamp is 118 dB with the unity gainbandwidth (UGBW)of 1 GHz, and the phase margin is 61°while the settling time is 5.8 ns when achieving 0.01% accuracy. The opamp is especially suitable for the frontend sample/hold (S/H)cell and the multiplying D/A converter(MDAC) module of the highspeed highresolution pipelined A/D converters(ADCs).

  15. Impact of semiconductor/metal interfaces on contact resistance and operating speed of organic thin film transistors

    KAUST Repository

    Wondmagegn, Wudyalew T.

    2010-09-24

    The contact resistance of field effect transistors based on pentacene and parylene has been investigated by experimental and numerical analysis. The device simulation was performed using finite element two-dimensional drift-diffusion simulation taking into account field-dependent mobility, interface/bulk trap states and fixed charge density at the organic/insulator interface. The width-normalized contact resistance extracted from simulation which included an interface dipole layer between the gold source/drain electrodes and pentacene was 91 kΩcm. However, contact resistance extracted from the simulation, without consideration of interface dipole was 52.4 kΩcm, which is about half of the experimentally extracted 108 kΩcm. This indicates that interface dipoles are critical effects which degrade performances of organic field effect transistors by increasing the contact resistance. Using numerical calculations and circuit simulations, we have predicted a 1 MHz switching frequency for a 1 μm channel length transistor without dipole interface between gold and pentacene. The transistor with dipole interface is predicted, via the same methods, to exhibit an operating frequency of less than 0.5 MHz. © 2010 Springer Science+Business Media LLC.

  16. OBLIQUE TOWING TEST AND MANEUVER SIMULATION AT LOW SPEED AND LARGE DRIFT ANGLE FOR DEEP SEA OPEN-FRAMED REMOTELY OPERATED VEHICLE

    Institute of Scientific and Technical Information of China (English)

    FAN Shi-bo; LIAN Lian; REN Ping; HUANG Guo-liang

    2012-01-01

    This article presents the newly designed oblique towing test in the horizontal plane for the scaled model of 4 500 m deep sea open-framed Remotely Operated Vehicle (ROV),which is being researched and developed by Shanghai Jiao Toug University.Accurate hydrodynamics coefficients measurement is significant for the maneuverability and control system design.The scaled model of ROV was constructed by 1∶1.6.Hydrodynamics tests of large drift angle were conducted through Large Amplitude Horizontal Planar Motion Mechanism (LAHPMM) under low speed.Multiple regression method is adopted to process the test data and obtain the related hydrodynamic coefficients.Simulations were designed for the horizontal plane motion of large drift angle to verify the coefficients calculated.And the results show that the data can satisfy with the design requirements of the ROV developed.

  17. Speeding Up

    Institute of Scientific and Technical Information of China (English)

    YU SHUJUN

    2010-01-01

    In the wake of the global financial crisis, China has amazed the world with the speed of its economic recovery. But what has been even more surprising is the speed of its railway evolution. The unveiling of the 1,069-km Wuhan-Guangzhou High-speed Railway on December 26, 2009 pushed China's high-speed rail sys-tem-the total mileage, the average speed and the technology-to rank first in the world almost overnight.

  18. Development of a novel parallel-spool pilot operated high-pressure solenoid valve with high flow rate and high speed

    Science.gov (United States)

    Dong, Dai; Li, Xiaoning

    2015-03-01

    High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system. However, traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously. A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system. A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design. Mathematical models of the opening process and flow rate of the valve are established. Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response. Corresponding formulas to solve 4 parts of the response time are derived. Key factors that influence the opening response time are analyzed. According to the mathematical model of the valve, a simulation of the opening process is carried out by MATLAB. Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve. Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool. The experimental results are in agreement with the simulated results, therefore the validity of the theoretical analysis is verified. Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa. The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s. According to the result of the load driving test, the valve can meet the demands of the driving system. The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

  19. Development of a Novel Parallel-spool Pilot Operated High-pressure Solenoid Valve with High Flow Rate and High Speed

    Institute of Scientific and Technical Information of China (English)

    DONG Dai; LI Xiaoning

    2015-01-01

    High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system. However, traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously. A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system. A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design. Mathematical models of the opening process and flow rate of the valve are established. Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response. Corresponding formulas to solve 4 parts of the response time are derived. Key factors that influence the opening response time are analyzed. According to the mathematical model of the valve, a simulation of the opening process is carried out by MATLAB. Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve. Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool. The experimental results are in agreement with the simulated results, therefore the validity of the theoretical analysis is verified. Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa. The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s. According to the result of the load driving test, the valve can meet the demands of the driving system. The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

  20. More Than Just Speed

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The 1,318-km Beijing-Shanghai High-Speed Railway will finally come into operation at the end of June.Since construction began three years ago,the speedy railway has grabbed worldwide attention because of its design as the world’s longest and fastesthigh-speed rail line utilizing the most advanced technology.

  1. 高速列车运行产生的轮轨噪声预测%Prediction of Wheel - rail Noise by Operating High Speed Train

    Institute of Scientific and Technical Information of China (English)

    杨新文; 翟婉明; 和振兴

    2011-01-01

    With the rising of train operation speed, wheel/rail noises are significantly increased. Based on vehicle-track coupled dynamics, random vibration theory and acoustics theory, a model is produced to predict wheel/rail noises by high speed hain operating due to wheel and rail surface roughness, geometric discontinuity in contact, and so on. And the corresponding software WRNOISE (Wheel/Rail Noise)is developed. Compared with existing prediction model TWINS (Track-Wheel Interaction Noise Software), the result shows that the main frequency ranges and trends of the noise of TWINS software simulation values and the present model computation values are consistent. Compared with the model STTIN (Simulation of Train-Track Interaction Noise), the present prediction model can be more fully taken into account the vibration and noise contribution in the axial direction of wheels and the lateral direction of rails. Compared with the noise test values of the high-speed train running on ballasted track and slab track, there are some differences between prediction values of the present model WRNOISE and noise test values, but both trends are in agreement mutually from the viewpoint of wheel-rail noise radiation dominant frequencies.%轮轨噪声随着列车运营速度的提高而显著增大,综合应用车辆-轨道耦合动力学、随机振动理论和声辐射理论,预测由轮轨表面粗糙度、接触不连续几何缺陷等激起的高速列车轮轨噪声,建立轮轨噪声预测模型,并开发相应软件WRNOISE(Wheel/rail Noise).与已有的轮轨噪声预测模型TWINS(Track-Wheel Interaction Noise Software)比较,预测的噪声主频和变化趋势与TWINS的预测结果一致;与STTIN(Simulation ofTrain-TrackInteraction Noise)模型相比,预测模型考虑车轮辐板和钢轨轨腰横向振动噪声的贡献;与有砟和无砟轨道路基区段噪声实测结果的对比表明,WRNOISE模型计算结果与实测结果仍存在一定差异,但

  2. High-speed highly temperature stable 980 nm VCSELs operating at 25 Gb/s at up to 85 °C for short reach optical interconnects

    Science.gov (United States)

    Mutig, Alex; Lott, James A.; Blokhin, Sergey A.; Moser, Philip; Wolf, Philip; Hofmann, Werner; Nadtochiy, Alexey M.; Bimberg, Dieter

    2011-03-01

    The progressive penetration of optical communication links into traditional copper interconnect markets greatly expands the applications of vertical cavity surface emitting lasers (VCSELs) for the next-generation of board-to-board, moduleto- module, chip-to-chip, and on-chip optical interconnects. Stability of the VCSEL parameters at high temperatures is indispensable for such applications, since these lasers typically reside directly on or near integrated circuit chips. Here we present 980 nm oxide-confined VCSELs operating error-free at bit rates up to 25 Gbit/s at temperatures as high as 85 °C without adjustment of the drive current and peak-to-peak modulation voltage. The driver design is therefore simplified and the power consumption of the driver electronics is lowered, reducing the production and operational costs. Small and large signal modulation experiments at various temperatures from 20 up to 85 °C for lasers with different oxide aperture diameters are presented in order to analyze the physical processes controlling the performance of the VCSELs. Temperature insensitive maximum -3 dB bandwidths of around 13-15 GHz for VCSELs with aperture diameters of 10 μm and corresponding parasitic cut-off frequencies exceeding 22 GHz are observed. Presented results demonstrate the suitability of our VCSELs for practical high speed and high temperature stable short-reach optical links.

  3. Effect of operating methods of wind turbine-generator system on net power extraction under wind speed fluctuations in fields; Hendo fukyoka deno doryoku chushutsu kara mita furyoku hatsuden system no unten seigyoho ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, T. [Japan Society for the Promotion of Science, Tokyo (Japan); Hashizume, T.; Ota, E. [Waseda University, Tokyo (Japan). School of Science and Engineering

    2000-01-25

    The effect of operating methods of wind turbine-generator system on net power extraction under wind speed fluctuations is discussed in relation to the dynamic behavior of the system. The system is composed of a Darrieus-Savonius hybrid wind turbine and a load generator. In this paper, two types of operating method are examined; constant tip speed ratio operation for stand-alone power systems (Scheme 1) and synchronous operation for utility power systems (Scheme 2). The computed results of the net extracting power using our dynamic simulation model show that the dominant factor of power extraction in Scheme 1 is the dynamic characteristics of rotational components and that it is important to select the appropriate rated wind speed in Scheme 2. Thus, it is concluded that a conformable operating method and rated power output of the system exist for each wind condition. In particular, small-scale systems, which are smaller than approximately 10 kW-system range, are desirable to be operated under a constant tip speed ratio as stand-alone power systems. (author)

  4. 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....

  5. Desempenho operacional de semeadura-adubadora em diferentes manejos da cobertura e da velocidade Operational performance of seeder in different forward speed and winter cover crop management

    Directory of Open Access Journals (Sweden)

    Carlos E. A. Furlani

    2007-08-01

    analysis. When the value of the F test was significant at 0.05 of probability, the Tukey test was carried out to compare the averages. The three managements in the vegetal covering culture did not influence the seeder performance. The force decreased with the increasing of the forward speed, the opposite happened to the operational field capacity and the power in the bar. The hourly consumption of fuel increased with the speed, while the operational decreased.

  6. Variable speed controller

    Science.gov (United States)

    Estes, Christa; Spiggle, Charles; Swift, Shannon; Vangeffen, Stephen; Younger, Frank

    1992-01-01

    This report details a new design for a variable speed controller which can be used to operate lunar machinery without the astronaut using his or her upper body. In order to demonstrate the design, a treadle for an industrial sewing machine was redesigned to be used by a standing operator. Since the invention of an electrically powered sewing machine, the operator has been seated. Today, companies are switching from sit down to stand up operation involving modular stations. The old treadle worked well with a sitting operator, but problems have been found when trying to use the same treadle with a standing operator. Emphasis is placed on the ease of use by the operator along with the ergonomics involved. Included with the design analysis are suggestions for possible uses for the speed controller in other applications.

  7. Do speed cameras reduce speeding in urban areas?

    Science.gov (United States)

    Oliveira, Daniele Falci de; Friche, Amélia Augusta de Lima; Costa, Dário Alves da Silva; Mingoti, Sueli Aparecida; Caiaffa, Waleska Teixeira

    2015-11-01

    This observational study aimed to estimate the prevalence of speeding on urban roadways and to analyze associated factors. The sample consisted of 8,565 vehicles circulating in areas with and without fixed speed cameras in operation. We found that 40% of vehicles 200 meters after the fixed cameras and 33.6% of vehicles observed on roadways without speed cameras were moving over the speed limit (p cameras, more women drivers were talking on their cell phones and wearing seatbelts when compared to men (p < 0.05 for both comparisons), independently of speed limits. The results suggest that compliance with speed limits requires more than structural interventions.

  8. Modification of AISI M2 high speed tool steels after laser surface melting under different operation conditions; Modificacion de los aceros rapidos de herramientas AISI M2 por fusion superficial con laser bajo diferentes condiciones de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Arias, J.; Cabeza, M.; Castro, G.; Feijoo, I.; Merino, P.; Pena, G.

    2010-07-01

    We applied a laser surface melting treatment to AISIM2 high-speed steel hardened and tempered- and studied the resulting surface characteristics (microstructure) and mechanical behavior (hardness and wear performance). The steel was treated using a Nd:YAG continuous-wave laser with different operation conditions. The influence of the laser processing parameters on the single tracks and on melted surface layer obtained by multipass system with 50% overlap were studied. The microstructure for all conditions is formed by MC- and M{sub 2}C-type carbides, martensite and retained austenite; the quantities of this phase depends on the operations conditions. It has been determined that low levels of power density and high speed scanning of the beam leads to greater homogeneity in the microstructure with high hardness values and wear resistance. (Author) 26 refs.

  9. Speed mathematics

    CERN Document Server

    Handley, Bill

    2012-01-01

    This new, revised edition of the bestselling Speed Mathematics features new chapters on memorising numbers and general information, calculating statistics and compound interest, square roots, logarithms and easy trig calculations. Written so anyone can understand, this book teaches simple strategies that will enable readers to make lightning-quick calculations. People who excel at mathematics use better strategies than the rest of us; they are not necessarily more intelligent. With Speed Mathematics you'll discover methods to make maths easy and fun. This book is perfect for stud

  10. Automatic speed control of highway traffic

    Science.gov (United States)

    Klingman, E. E.

    1973-01-01

    Vehicle control system monitors all vehicles in its range, and automatically slows down speeding vehicles by activating governor in vehicle. System determines only maximum speed; speeds below maximum are controlled by vehicle operator. Loss of transmitted signal or activation of emergency over-ride will open fuel line and return control to operator.

  11. Research on Operating Characteristics and Driving Method of High—speed On—off Valve in Clutch Starting%离合起步用高速开关阀工作特性与驱动方法研究

    Institute of Scientific and Technical Information of China (English)

    夏晶晶

    2012-01-01

    In general pulse width modulation (PWM) signal driven,the high - speed on - off solenoid valve opening and closing time are longer,slower reaction, which affected the high-speed on-off solenoid valve control performance. In order to improve the control performance of the high-speed valve,on the basis of the analyses in the operating characteristics of high - speed on - off valve, a multi - hybrid driving method was designed to shorten the opening and closing time,reduce the pressure fluctuations in pressure control to improve the control performance of the valve. In vehicle clutch control,the use of the above method can improve the starting performance,and the engine speed is relatively stable,the driven plate speed increasing trend fluctuation is smaller.%在普通脉宽调制(PWM)信号驱动下,高速开关电磁阀的开启和关闭时间较长,反应慢,影响了高速开关电磁阀的控制性能.为了进一步提高高速开关阀的控制性能,在分析高速开关阀工作特性的基础上,提出了多路混合驱动方法,缩短了高速开关阀的开启和关闭时间,减小了压力控制时的压力波动,改善了高速开关阀的控制性能.在汽车离合器起步控制中,使用该方法很好地改善了汽车的起步性能,发动机转速比较平稳,从动盘转速增加趋势的波动较小.

  12. 一级公路路侧冲突强度与运行速度的相关性%Relationship between Roadside Conflict Intensity and Operating Speed of First Class Highway

    Institute of Scientific and Technical Information of China (English)

    常成利; 荣建; 任福田

    2011-01-01

    First class highway is one type of general multi-lane highway which takes the role of arterial function and collector-distributor function in domestic road network. Mixed traffic is very popular in Chinese highway system. Roadside conflict affects traffic operating speed, and quantitative analysis of influence of roadside conflict on traffic operating speed is an important job in highway design stage. Through investigation of driver's visual impression on different roadside conflict types, roadside conflict intensities were classified into four levels. Seven typical first class highway sections were chosen for observing traffic data, which were analysed by the method of variance analysis. The result indicates that when using V85 as the evaluation index of operating speed, the effect of roadside conflict is remarkable. By establishing the relationship between roadside conflict intensity level and V85 free flow operating speed, the influence of roadside conflict intensity on operating speed of first class highway was quantified.%一级公路是我国公路网中承担干线功能和集散功能的多车道普通公路形式.混行交通在我国公路交通中普遍存在,路侧冲突对交通流运行速度产生影响,定量分析路侧冲突对交通流的影响是公路设计的重要工作.通过调查驾驶员对不同路侧冲突类型的直观印象,为路侧冲突定义了4个强度等级,选择国内7个具有代表性的典型一级公路路段进行交通流数据观测,采用方差分析技术对试验数据进行分析.结果表明:当采用自由流速度的85%位车速作为运行速度的评价指标时,路侧冲突强度的影响是显著的.通过建立起路侧冲突强度等级与85%位自由流速度之间的关系,量化了路侧冲突强度对一级公路运行速度的影响.

  13. 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.

  14. 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.

  15. Research on Inserting Turnout into High Speed Ballastless Track Railway in Operation%高速铁路运营线无砟轨道地段插入道岔技术研究

    Institute of Scientific and Technical Information of China (English)

    李秋义

    2016-01-01

    随着我国高速铁路网建设的不断深入和完善,大量新建线路需要引入既有车站或枢纽,我国高速铁路建设运营线无砟轨道地段插入道岔的功能需求日显迫切,已成为制约我国高速铁路建设的关键技术难题。结合某新建高速铁路引入既有高铁站的接轨方案,提出拆除既有无砟轨道、新铺无砟道岔技术方案,通过设置安全隔离板墙,封锁一线施工,相邻正线单线行车,采用新材料、新工艺、新技术等系列措施,可确保施工安全和缩短工期,减少对运营的影响。该方案解决了高铁车站或枢纽无砟轨道接轨的技术难题,实现新建高速铁路线路与既有枢纽的成功引入。%With the development and improvement of China high-speed railway network, a large number of new railways are introduced into the existing stations or hubs and turnouts need to be installed urgently on busy ballastless track lines, which challenges high-speed railway development. With reference to the track connection scheme of one high-speed railway to the existing high-speed railway station, this paper proposes the technological scheme by removing existing ballastless track and laying new ballastless turnout. Such measures as setting up security isolation wall, blocking one line for construction while allowing the adjacent line in operation, and employing new materials, new processes and new technologies are taken to ensure construction safety, shorten construction period and reduce impact on railway operation. The scheme resolves the technological problem of track connection in high-speed railway stations or hubs and fulfills the introduction of new high-speed railway into existing hubs.

  16. 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.

  17. 14 CFR 91.117 - Aircraft speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft speed. 91.117 Section 91.117... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Flight Rules General § 91.117 Aircraft speed. (a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10...

  18. Research on ergonomics experimental system of emergency operation for high-speed train%高速列车应急作业工效学实验系统研究

    Institute of Scientific and Technical Information of China (English)

    郭北苑; 巨建涛; 王雅楠; 方卫宁

    2013-01-01

    高速列车司机应急作业的可靠性对维护列车正点安全运行具有重要作用,但在实际列车运行中无法开展针对司机应急作业特性的工效学实验,因此有必要构建高速列车应急作业流程工效学实验系统,以便在实验室环境下开展相关研究.高速列车应急作业流程工效学实验系统由实验管理子系统、应急作业子系统和工效学数据采集子系统3个子系统组成,该系统设计中引入了故障注入技术,实现了故障注入、辅助处理等管理操作;系统还能完成司机应急作业操作中相关工效学数据采集功能.系统已成功应用于CRH2型高速列车应急作业流程工效学实验中.%Emergency operation reliability of the high-speed train drivers plays an important role in train safe operation maintenance, but in actual train operation, since the driver operation is forbidden from disturbance and the fault scenario is unable to be controlled, the ergonomics experiment about driver emergency operation characteristics can't be carried out, so it is necessary to construct an ergonomics experiment system with highspeed train emergency operation procedures and carry out some related experiments in laboratory environment. This system consists of experimental management subsystem, emergency operation subsystem and ergonomics data acquisition subsystem. In the design of the system, the fault injection technology is introduced to realize the two experimental management operations of fault injection and the auxiliary handle. Also this system can acquire the ergonomics data about the driver emergency operations. This system has been successfully used in the ergonomics experiment on the emergency operation procedures of CRH2 high-speed train.

  19. Transplantio semi-mecanizado de mudas de tomate em função da velocidade de operação = Semi-mechanized transplanting of tomato seedlings under operating speeds

    Directory of Open Access Journals (Sweden)

    Túlio de Almeida Machado

    2015-03-01

    Full Text Available O transplantio semi-mecanizado de mudas de tomate industrial tem se tornado uma alternativa viável para os produtores, visto que possibilita o aumento da capacidade operacional. Com o objetivo de avaliar a influência da velocidade de operação e repasse dos trabalhadores do campo no estande final, o trabalho foi conduzido em uma área de 58 ha irrigada por meio de um pivô central. O presente trabalho foi realizado a partir da implantação do híbrido HEINZ 9553, empregando uma transplantadora da marca Ferrari modelo FX, tracionada por um trator da marca New Holland, modelo TM 7010, 4x2 com tração dianteira auxiliar. As velocidades analisadas foram de 1,83; 1,66 e 1,56 km h-1, sendo que a contagem das mudas foi obtida após a demarcação e a passagem do conjunto mecanizado pelas parcelas delimitadas. A análise da influência da velocidade no transplantio foi realizada por meio da utilização de cartas de controle e da média móvel exponencialmente ponderada (MMEP, na qual os dados foram analisados em função das velocidades e dos estandes estimados em cada ponto. As velocidades de transplantio modificaram os estandes finais nos processos estudados e esse fato pode ser explicado devido a uma falta de uniformidade de espaçamento entre as mudas transplantadas. Apenas na velocidade de 1,83 km h-1 todas as observações se mantiveram sob controle em ambas as situações. O controle estatístico de processos através da utilização de cartas de controle e da média móvel exponencialmente ponderada foram ferramentas adequadas para avaliação do estande final. = The tomato semi-mechanized transplanting has become a viable alternative for producers, since it allows increased operational capacity of fieldwork. In order to evaluate the influence of operating speed of the transplanting process, a study was conducted in an experimental area of 58 ha irrigated by a center pivot. This study was conducted from the deployment of the hybrid HEINZ

  20. 高速列车节能运行优化控制方法研究%Research on Optimization Control Method of Energy-saving Operation of High-speed Trains

    Institute of Scientific and Technical Information of China (English)

    刘建强; 魏远乐; 胡辉

    2014-01-01

    Energy-saving operation of high-speed trains is of utmost importance to saving energy and reducing consumption .In this paper ,applying the modern optimal control theory and considering feedback of regenera-tive braking energy ,the minimum energy consumption calculation model of high-speed trains was established under constraint of fixed running time .The optimal control principle was worked cut with the minimum formu-la ,which was the combination of four kinds of operation modes ,i .e .,the maximum traction ,uniform speed , idle running and maximum braking .Then according to the actual train characteristic curve and measured resist-ance curve ,a new energy-saving operation control method was proposed .With this method ,the maximum train running speed corresponding to the lowest energy consumption was found .Thus every working point of the maximum traction ,uniform speed ,idle running and maximum braking versus the minimum energy con-sumption for the whole journey was calculated .In order to verify the effectiveness of the proposed method ,the energy-saving operation control method was applied to CRH3 (EMUs) running between Beijing and Tianjin . The results show that the energy consumption decreases about 14% compared with the actual test results .The study provides a basis for energy-saving operation control of high-speed trains .%高速列车节能运行控制对高速列车节能降耗至关重要。基于现代最优控制理论,考虑列车再生制动能量反馈,建立高速列车在定时约束条件下最小能耗计算模型,利用极小值公式推导得到最佳控制原则为最大牵引、匀速、惰行及最大制动这4种运行方式组合。在此基础上,依据高速列车牵引特性和阻力特性曲线,提出一种列车节能运行控制方法,基于此方法求解得到列车运行能量消耗最低所对应的最大速度值,从而计算得出整个运行过程中列车运行能量消耗最小时最大牵引、匀速、惰

  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 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...

  3. Seeding quality and soybean yields from using different furrowers and operation speedsQualidade de semeadura e produtividade da soja sob diferentes sulcadores e velocidades de operação

    Directory of Open Access Journals (Sweden)

    Alcir José Modolo

    2012-12-01

    Full Text Available The sowing process for annual no-till crops affects the physical soil conditions around the seeds by exposing them to adverse conditions that may limit initial plant development and reduce potential yield. The use of seed drills that are not compatible with field conditions and the use of inappropriate seed drill speeds affect sowing performance. Therefore, this study aims to evaluate the effect of different seed drill types and operating speeds on soybean quality parameters and yield components. Two furrow opener (double disc and chisel and four operating speed (0.86; 1.22; 1.47 and 1.94 m s-1 treatments were used. The following variables were evaluated: mean number of days until emergence, plant distribution uniformity, sowing depth, area of the soil disturbed, crop stand and grain yield. Overall, the chisel furrow opener provided a greater sowing depth and increased the disturbed soil area more than the double disc furrow opener. Increased operating speeds reduced crop stands and yields and increased the disturbed soil area. Em culturas anuais submetidas ao sistema plantio direto o processo de semeadura afeta o condicionamento físico do solo ao redor das sementes expondo as mesmas a condições adversas, podendo limitar o desenvolvimento inicial das plantas e minimizar o potencial produtivo. O uso de sulcadores não condizentes com a situação de campo e de velocidades inadequadas são fatores que afetam o bom desempenho da semeadura. Nesse contexto, este trabalho teve por objetivo, avaliar o efeito de diferentes sulcadores e velocidades de operação sobre parâmetros de qualidade de semeadura e componentes de produtividade da cultura da soja. Os tratamentos foram compostos pela combinação entre dois sulcadores (disco e haste e quatro velocidades de operação (0,86; 1,22; 1,47 e 1,94 m s-1. Foram avaliados: o número médio de dias para a emergência, a uniformidade de distribuição de plantas, a profundidade de semeadura, a área de

  4. 14 CFR 25.1515 - Landing gear speeds.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  5. 32 CFR 935.132 - Speed limits.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Speed limits. 935.132 Section 935.132 National... WAKE ISLAND CODE Motor Vehicle Code § 935.132 Speed limits. Each person operating a motor vehicle on..., or both; and (b) That does not exceed 40 miles an hour or such lesser speed limit as may be posted....

  6. Analysis on the Failure Mode of Power - operated High - speed Precision Chuck%高速精密动力卡盘的失效形式分析研究

    Institute of Scientific and Technical Information of China (English)

    龚俊; 汤文成; 韦鸣; 张震宇

    2012-01-01

    对高速精密动力卡盘的失效形式进行了分析研究,提出了避免在预定寿命期内失效的要求,建立了失效鱼骨图.分析动力卡盘的材料选择和热处理技术、摩擦磨损和精度对动力卡盘失效的影响,对卡盘的优化设计和应用以及夹紧力计算具有指导意义.%It analyzes the failure mode of power - operated high speed precision chuck, proposes the requirements of failure in the lifespan, builds the fishbone diagram. It gives the detail about the impact of the material selection of chuck and heat treatment technology, the precision impact analysis on wear and tear. The results provide reliable technical supports for the optimization of the design and application of power - operated high speed precision chuck.

  7. Comparison of Computational and Experimental Results for a Transonic Variable-speed Power-Turbine Blade Operating with Low Inlet Turbulence Levels

    Science.gov (United States)

    Booth, David T.; Flegel, Ashlie B.

    2015-01-01

    A computational assessment of the aerodynamic performance of the midspan section of a variable-speed power-turbine blade is described. The computation comprises a periodic single blade that represents the 2-D Midspan section VSPT blade that was tested in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. A commercial, off-the-shelf (COTS) software package, Pointwise and CFD++, was used for the grid generation and RANS and URANS computations. The CFD code, which offers flexibility in terms of turbulence and transition modeling options, was assessed in terms of blade loading, loss, and turning against test data from the transonic tunnel. Simulations were assessed at positive and negative incidence angles that represent the turbine cruise and take-off design conditions. The results indicate that the secondary flow induced at the positive incidence cruise condition results in a highly loaded case and transitional flow on the blade is observed. The negative incidence take-off condition is unloaded and the flow is very two-dimensional. The computational results demonstrate the predictive capability of the gridding technique and COTS software for a linear transonic turbine blade cascade with large incidence angle variation.

  8. High speed flux feedback for tuning a universal field oriented controller capable of operating in direct and indirect field orientation modes

    Science.gov (United States)

    De Doncker, Rik W. A. A.

    1992-01-01

    The direct (d) and quadrature (q) components of flux, as sensed by flux sensors or determined from voltage and current measurements in a direct field orientation scheme, are processed rapidly and accurately to provide flux amplitude and angular position values for use by the vector rotator of a universal field-oriented (UFO) controller. Flux amplitude (linear or squared) is provided as feedback to tune the UFO controller for operation in direct and indirect field orientation modes and enables smooth transitions from one mode to the other.

  9. Combining conventional and thermal drilling in order to increase speed and reduce costs of drilling operations to access deep geothermal resources

    Science.gov (United States)

    Rossi, Edoardo; Kant, Michael A.; von Rohr, Philipp Rudolf; Saar, Martin O.

    2017-04-01

    The exploitation of deep geothermal resources for energy production relies on finding cost effective solutions to increase the drilling performance in hard rocks. Conventional rotary drilling techniques, based on mechanical rock exportation, result in high rates of drilling tool wearing, causing significant costs. Additionally, rotary drilling results in low drilling speeds in the typically hard crystalline basement rocks targeted for enhanced geothermal energy utilization technologies. Furthermore, even lower overall drilling rates result, when considering tripping times required to exchange worn drill tools. Therefore, alternative drilling techniques, such as hammering, thermal drilling, plasma drilling, and jetting processes are widely investigated in order to provide cost-effective alternatives to conventional drilling methods. A promising approach, that combines conventional rotary and thermal drilling techniques, is investigated in the present work. Here, the rock material is thermally weakened before being exported by conventional cutters. Heat is locally provided by a flame, which moves over the rock surface, heat-treating the material. Besides reducing the rock strength, an in-depth smoothening effect of the mechanical rock properties is observed due to the thermal treatment. This results in reduced rates of drill bit wearing and higher rates of penetration, which in turn decreases drilling costs significantly, particularly for deep-drilling projects. Due to the high heating rates, rock-hardening, commonly observed at moderate temperatures, can be avoided. The flame action can be modelled as a localized, high heat transfer coefficient flame treatment, which results in orders of magnitude higher heating rates than conventional oven treatments. Therefore, we analyse rock strength variations after different maximum temperatures, flame-based heating rates, and rock confinement pressures. The results show that flame treatments lead to a monotonous decrease of

  10. Risk identification and optimization of the post chain on the high-speed rail operation process%高铁运营过程岗位链条安全风险识别与优化分析

    Institute of Scientific and Technical Information of China (English)

    王洪德; 孙海云

    2016-01-01

    为有效预防和减少高铁运营事故,消除高铁运营过程岗位链条安全风险识别存在的主观性较强、可操作性较弱的缺陷,降低安全风险因子获取的随机性,基于危险与可操作性研究方法,研究高速铁路运营过程岗位链条安全风险识别与优化问题.首先,基于对线路基础、运行调度、列控中心及列车运行系统的研究,建立高铁运营过程岗位链条模型;然后,采用危险与可操作性分析方法对运行调度进行安全风险因子识别,涉及“钢轨”、“道床”、“路基”、“桥隧建筑物”、“道岔”、“信号设备”、“接触网”、“供电设备”8大设施设备;最后,运用粗集理论对安全风险指标体系进行优化分析.结果表明,外轨超高、路基翻浆冒泥、桥隧建筑物坍塌、道岔故障、信号设备故障、接触网供电线路中断6大因素为运行调度单元的核心风险影响因素.%The paper is aimed at proposing an hazard and operability analysis (HAZOP) method for the high-speed railway operation and management in hoping to prevent or at least to reduce the high-speed railway transportation accidents remarkably.For the said purpose,we have to explore the possibility on how to reduce the liabilities of the objectionable subjectivity and mindless commanding in the actual process.Therefore,it is of great need to define and determine the appropriate instructions,the degree of deviation of the parameters in each area,in addition to the failure and adverse effects of the operation involved,so as to fulfill the high speed railway operation process,for which great attention should be paid to the safety risk identification and optimization of the operation.In doing so,first of all,it is necessary to establish a railway operational control center and system based on the total rail-line operation schedule system based on the duty-service chain models.Secondly,it is necessary to illustrate all the safety

  11. 灾变事件下高速公路限速标准的可靠性分析%RELIABILITY ANALYSIS OF MAXIMUM SPEED LIMIT FOR EXPRESSWAY OPERATION AGAINST DISASTROUS EVENTS

    Institute of Scientific and Technical Information of China (English)

    陈富坚; 黄世斌; 包惠明

    2011-01-01

    To solve the problems in the current deterministic method for determining a maximum speed limit for expressway operation against disastrous events, a reliability method was presented. The dynamic analysis was made for vehicle traveling at a horizontal curve of expressway, and respective maximum allowable speeds were deduced for vehicle in horizontal circular motion without sliding and that in emergency stopping without hitting an obstacle in the visual range. Based on Reliability engineering, the reliability of a maximum speed limit was defined. With safety of horizontal circular motion and emergency stopping as constraints, the performance function of the maximum speed limit was established and the model for calculation of its reliability and reliable indicator were deduced. For solution of the reliability model, Monte Carlo method was recommended due to multi-parameter high complexity of the non-linear performance function. With a self-developed program, a case study was conducted to illustrate the reliability analysis of the maximum speed limit for expressway safety management under a detrimental event. The reliability method for determining a maximum speed limit of expressway operation is helpful for improving traffic safety.%针对灾变事件下高速公路安全管理中采用定值型限速标准存在的问题,对基于可靠性的限速标准进行了探讨.通过对高速公路平曲线路段车辆行驶的动力学分析,推导了车辆作圆周运动而不发生横向滑移的最大允许车速,以及司机在弯道内发现障碍物而紧急安全停车的最大允许速度.以可靠性工程理论为依据,对高速公路限速标准的可靠度进行了定义,并以圆周运动安全和紧急刹车安全为约束条件建立了高速公路限速标准的功能函数,推导了相应的可靠性计算模型.针对限速标准功能函数的多参数复杂非线性特征,提出采用Monte Carlo法对限速标准可靠性计算模型进行求解.以所

  12. 49 CFR 213.57 - Curves; elevation and speed limitations.

    Science.gov (United States)

    2010-10-01

    ... the following formula— ER22JN98.001 Where— Vmax = Maximum allowable operating speed (miles per hour... appendix A is a table of maximum allowable operating speed computed in accordance with this formula for... following formula— ER22JN98.002 Where— Vmax = Maximum allowable operating speed (miles per hour)....

  13. 实心转子感应电动机高速运转性能分析%Analysis of high-speed operation performance of induction motor with solid rotor

    Institute of Scientific and Technical Information of China (English)

    王映红

    2013-01-01

    The paper analyzed magnetic circuit and M-S curve of induction motor with solid rotor,used Ansoft finite element software to simulate dynamic process of variable frequency starting of the motor,and got dynamic data of no-load starting including magnetic field distribution,stator and rotor current,starting torque and so on.It detected performance of the motor under the condition of high frequency and high speed,and demonstrated feasibility of high-speed operation of the induction motor with solid rotor.%分析了实心转子感应电动机的磁路及M-S曲线;采用Ansoft有限元软件对电动机变频启动的动态过程进行仿真,得到了空载启动的磁场分布、定转子电流、启动转矩等动态数据;测试了电动机在高频高速状态下的性能,论证了实心转子感应电动机高速运行的可行性.

  14. Influence of subway train speed on operation-induced settlement of shield tunnel%地铁行车速度对盾构隧道运营沉降的影响分析

    Institute of Scientific and Technical Information of China (English)

    姜洲; 高广运; 赵宏

    2015-01-01

    increases. The longitudinal differential settlement has significant adverse effect on the operation of subway tunnel. As the train speed increases, this effect becomes more significant. When the tunnel differential settlement is small and the track condition is good, tunnel operation settlement decreases as the metro driving speed increases. However, the long-term settlement of tunnel significantly increases as vehicle speed increases, while the foundation differential settlement becomes pronounced and the track irregularities are significant.

  15. 某款车用发电机低速噪声源的识别与控制%Identification and Reduction of the Noise Source of a Vehicle's Generator Operation in Low Speed Range

    Institute of Scientific and Technical Information of China (English)

    石晓辉; 昌诗力; 施全; 易鹏

    2015-01-01

    针对某款车用发电机低速噪声偏大的问题,首先进行发电机台架噪声试验,运用阶次分析找到主要特征阶次.采用数值模拟和试验验证相结合的方法对车用发电机结构进行模态分析,计算出发电机的前几阶固有频率与模态振型.结合噪声试验分析结果与模态特性,得出低速噪声偏大是由于发电机在电磁力波的激励下发生了共振的结论.最后提出改进建议,改进后的电机低速下噪声得到明显的改善,总体声压级降低约2 dB(A),共振处声压级降低约5 dB(A).%The problem of overlarge noise of a vehicle's generator operating in low speed range was studied. Firstly, the noise was tested in a test bench and the main orders of the noise were found by order analysis. Secondly, both numerical simulation and experimental test were applied to the modal analysis of the vehicle's generator, and the natural frequencies and vibration modes of the previous orders of the vehicle's generator were calculated. Thirdly, through the comprehensive analysis of the test results of noise and the modal characteristics, it was concluded that the overlarge noise in low speed range was caused by the generator's resonance inspired by electromagnetic force wave. Finally, some improvement suggestions were provided and the noise of the vehicle's generator operating in low speed range was reduced distinctly, the overall noise dropped by 2 dB(A), and the noise in the resonance point dropped by 5 dB(A).

  16. Speed Optimization in Liner Shipping Network Design

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard; Karsten, Christian Vad; Pisinger, David

    In the Liner Shipping Network Design Problem (LSNDP) services sail at a given speed throughout a round trip. In reality most services operate with a speed differentiated head- and back-haul, or even individual speeds on every sailing between two ports. The speed of a service is decisive...... for the bunker consumption in the network as well as the transit time of cargo. Speed optimization has been considered for tramp shipping showing significant reductions in fuel consumption. However, variable speeds has not been considered for post optimization of the LSNDP, where speed optimization could result...... in changes to the cargo flow due to transit time restrictions as well as significant savings in fuel consumption and required vessel deployment due to a weekly frequency requirement. We present a heuristic method to calculate variable speed on a service and present computational results for improving...

  17. 电力牵引货运列车节能运行研究(二):速度跟踪组合控制方法%Energy-efficient Freight Train Operation-Part Ⅱ:Combined Control of Speed Tracking

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Based on the given optimized target speed profile and in view of the nonlinear,large lag,multi-con-straint and multi-objective characteristics of freight train operation,this paper focused on the study of speed tracking control.Firstly,according to the characteristics of the controlled object,a multi-modal fuzzy PID (MMFPID)control algorithm was presented on the basis of a brief analysis of the PI control,which is general-ly used in trains in active service.Secondly,in order to deal with the large lag of freight trains,the paper a-dopted the traction feed forward approach,which improved the dynamic performance of the controller.Third-ly,for the bump line brake problems in low speed limit sections caused by speed overshoot,the strategy of lo-cal output limit was adopted and received satisfactory results without increasing the safety allowance for speed limit.Finally,with the help of a self-developed software simulation platform,the combined control method presented in this paper was compared with the traditional PID and fuzzy control.The results showed the satis-factory control effect of MMFPID,and excellent adaptability to different application scenarios with its multi-modal structure.%本文在目标速度优化曲线给定的基础上,针对货运列车运行过程的非线性、大滞后、多目标、多约束的特点,围绕速度跟踪控制问题展开研究.在对现役列车普遍采用的PI控制进行简要分析的基础上,针对被控对象的特点,提出多模态模糊PID控制算法(MMFPID).为应对货运列车的大滞后特性,采用牵引力前馈的方法,较好地提升了控制器的动态性能.针对车速超调在低限速区段引起的撞线制动问题,采用局部输出限幅的策略,在无需增加限速安全裕量的同时,收到了满意的效果.借助于自行开发的软件仿真平台,将本文提出的组合控制方法与经典的PID和模糊控制进行了对比仿真.结果表明,MMFPID不仅具有满意的控制效果,

  18. 14 CFR 29.931 - Shafting critical speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting critical speed. 29.931 Section 29... speed. (a) The critical speeds of any shafting must be determined by demonstration except that...) If any critical speed lies within, or close to, the operating ranges for idling, power-on,...

  19. 14 CFR 27.931 - Shafting critical speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting critical speed. 27.931 Section 27... speed. (a) The critical speeds of any shafting must be determined by demonstration except that...) If any critical speed lies within, or close to, the operating ranges for idling, power on,...

  20. 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.

  1. 49 CFR 213.329 - Curves, elevation and speed limitations.

    Science.gov (United States)

    2010-10-01

    ... by the following formula: ER22JN98.009 Where— Vmax = Maximum allowable operating speed (miles per... with this formula for various elevations and degrees of curvature for track speeds greater than 90 m.p... maximum operating speed for each curve may be determined by the following formula: ER22JN98.008...

  2. Study of the Current Compensation Control Strategy for EPS in High-speed and Large Steering Angle Operation%高速大转角工况下EPS电流补偿控制策略研究

    Institute of Scientific and Technical Information of China (English)

    吴星男; 江浩斌; 唐斌; 王志忠

    2013-01-01

    为提高车辆在高速大转角工况下的横向稳定性,以装备管柱式EPS的某微型乘用车为研究对象,建立其非线性3自由度整车模型,对车辆转向特性和转向行驶稳定性进行理论分析;在没有电子稳定程序或车辆动态稳定性控制装置的情况下,引入可控的补偿电流对EPS控制策略进行改进,并在matlab/simulink中进行仿真分析。结果表明,所研究的EPS电流补偿控制策略有效提高了高速大转角时车辆转向系统阻尼,增强了车辆的横向稳定性和驾驶员“路感”,使车辆的横摆运动得到良好控制。%In order to improve the vehicle's lateral stability in high-speed and large steering angle operation, the researchers established a 3-DOF model of the whole vehicle using a mini passenger car equipped with column-type EPS as research object, and analyzed vehicle steering characteristic and steering stability theoretically. A controllable compensation current has been introduced to improve the control strategy for EPS with the absence of electronic stability program (ESP) or vehicle dynamic control (VDC) system. The simulation was made in Matlab/Simulink. The results show that the EPS current compensation control strategy has effectively increased the steering system damping in high-speed and large steering angle operation, it has also enhanced the lateral stability and the road feel. The vehicle's yaw motion is well controlled.

  3. Measures for speed management.

    NARCIS (Netherlands)

    2009-01-01

    Measures for speed management are essential for limiting the negative effects of driving too fast and at inappropriate speeds. To begin with, safe and credible speed limits need to be determined. Dynamic and variable speed limits that take into account the current circumstances, such as weather cond

  4. 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.

  5. 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

  6. Operational Modal Analysis of Bogie Frame and Its Effect on Vibration Transfer of High-speed Train%转向架构架工作模态及其对车下振动传递影响初探

    Institute of Scientific and Technical Information of China (English)

    刘佳; 赵悦; 凌亮; 圣小珍

    2015-01-01

    In order to learn the dynamic characteristics of the bogie frames of high-speed trains in traveling status, an operational modal test of the bogie was carried out. The cross spectra between the response points of the bogie frame were obtained and the modal parameters were identified by using the Least Square Complex-Frequency Method. According to the results of the identification, the pseudo modals corresponding to the obvious vibration peaks in the acceleration of the bogie induced by the excitation of the axle box were removed so that the true modal parameters were obtained. According to the measured frequency spectrum of the axle box and floor vibration, sources of the floor vibration peak frequencies were found, and the effect of the bogie frame’s operational modes on the prominent peaks was analyzed. The measured data is very useful for understanding the dynamic characteristics of the train bogie frames in operation status and the mechanism of obvious peaks of the carriage’s floor vibration. The methods of the test and modal parameter identification may provide a reference for part’s operational modal test of high-speed trains.%为进一步了解运行过程中转向架构架的真实动态特性,对实际线路运行的某高速列车进行工作模态测试,获取构架响应点之间的互谱信号并进行模态参数识别。模态参数识别方法采用最小二乘复频域法。根据其识别结果,剔除由轴箱传至构架且引起构架显著峰值的虚假模态,获得构架真实工作模态参数。结合轴箱、车体外地板振动实测频谱,找到车体外地板显著振动频率来源,进而分析转向架工作模态对车体外地板振动显著峰值的影响。本文的相关实测结果为了解运行过程中转向架构架真实动力学行为、研究车体外地板振动显著频率的产生、传递机理提供依据;同时,测试及模态参数识别方法为车体运行部件工作模态试验提供参考。

  7. Manejos de cobertura vegetal e velocidades de operação em condições de semeadura e produtividade de milho Management of cover vegetation and speed of operation on conditions of sowing and corn yield

    Directory of Open Access Journals (Sweden)

    Emerson Trogello

    2013-07-01

    Full Text Available Objetivou-se, com este trabalho, avaliar parâmetros da qualidade de semeadura e o desenvolvimento e rendimento da cultura do milho semeada no sistema plantio direto sobre diferentes manejos de cobertura vegetal e velocidades de operação da semeadora-adubadora na região sudoeste do estado do Paraná. Utilizou-se esquema de parcelas subdivididas, as quais constituíram os manejos de cobertura vegetal da aveia preta (aveia gradeada, rolada, triturada e dessecada e as subparcelas as velocidades de operação (4,5 e 7,0 km h-1 no delineamento de blocos ao acaso, com quatro repetições. Avaliaram-se o espaçamento entre plantas, a uniformidade de distribuição de sementes, a profundidade de semeadura, o índice de velocidade de emergência, o estande de plantas, a área de solo mobilizada e a produtividade média da cultura. Os dados tabulados foram analisados pelo teste F a 0,05 e, apresentando significância, as médias foram comparadas pelo teste de Tukey a 0,05 de probabilidade. Concluiu-se que a melhor distribuição de sementes foi observada na menor velocidade e a produtividade média da cultura não foi influenciada pelos tratamentos. Os manejos de cobertura vegetal não se mostraram eficientes na melhoria das condições de semeadura.The objective of this study was to evaluate quality parameters of sowing and the development and yield of maize sown in no tillage system under different vegetation managements and operating speeds of the seeder in the southwest region of the S tate of Paraná. A split-plot design was used, where the plots were the vegetation management of the oat (oat latticed, rolled, chopped and desiccated and split plot the operation speeds (4.5 and 7.0 km h-1, in a randomized block design with four replications. The spacing between plants, uniformity distribution of seed, sowing depth, rate of emergence, plant stand, soil area mobilized and yield of the crop were evaluated. The tabulated data were analysed by F test at

  8. 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...

  9. 一种带有增益提高技术的高速CMOS运算放大器设计%Design of a high speed CMOS operational amplifier with gain boosting technique

    Institute of Scientific and Technical Information of China (English)

    宋奇伟; 陆安江; 张正平

    2012-01-01

    设计了一种用于高速ADC中的高速高增益的全差分CMOS运算放大器。主运放采用带开关电容共模反馈的折叠式共源共栅结构,利用增益提高和三支路电流基准技术实现一个可用于12~14 bit精度,100 MS/s采样频率的高速流水线(Pipelined)ADC的运放。设计基于SMIC 0.25μm CMOS工艺,在Cadence环境下对电路进行Spectre仿真。仿真结果表明,在2.5 V单电源电压下驱动2 pF负载时,运放的直流增益可达到124 dB,单位增益带宽720 MHz,转换速率高达885 V/μs,达到0.1%的稳定精度的建立时间只需4 ns,共模抑制比153 dB。%A fully differential opamp used in a high speed ADC was designed.The main amplifier is a folded cascode amplifier with SC CMFB.The opamp can be used in a 12 bit、100MS/s high speed Pipelined ADC with gain boosting and the triple-branch current reference technique.The operational amplifier is implemented in a standard 0.25 μm CMOS process,simulated with Spectre under Cadence.With 2.5 V power supply and 2 pF load capacitance has a DC gain of 124 dB,a unity gain bandwidth of 720 MHz,Slew Rate of 885 V/μs,4 ns settling time and 153dB CMRR.

  10. Operation Optimization of Constant-speed Circulating Water Pumps in a Thermal Power Plant under Full Conditions%火电机组定速循环水泵的全工况运行优化

    Institute of Scientific and Technical Information of China (English)

    刘吉臻; 王玮; 曾德良; 常太华; 柳玉

    2011-01-01

    为解决枚举法得出的定速循环水泵最优运行方式的局限性,通过分析汽轮机低压缸、冷却塔及凝汽器真空的全工况计算模型,提出了在环境温度相等的前提下进行循环水泵全工况运行优化,并对其流程进行了阐述,将排汽压力对汽轮机功率的修正曲线进行了全工况拟合,利用二分法求解机组各工况下循环水泵相邻运行方式的等效益点,进而获得等效益曲线,并采用二分法对某电厂的定速循环水泵进行了等效益曲线实例验证.结果表明:循环水泵优化运行后,平均可降低煤耗0.594g/(kw·h).%In order to overcome the limitation of optimized operation of constant-speed circulating water pumps obtained by enumeration method, the idea of optimizing the operation of circulating water pumps under full conditions was proposed on the premise of equal inlet temperature of cooling water, based on a- nalysis of full-condition calculation models for low-pressure cylinder, cooling tower and condenser vacuum. The specific optimization process is to fit the corrective curve between turbine power and exhaust pressure under full conditions, then to solve the equal efficiency points between adjacent operating modes of circu- lating water pumps by dichotomy method, and finally to acquire the equal efficiency curves. Verification results on the equal efficiency curves in a certain power plant show that an average of 0. 594 g/(kw .h) net coal consumption can be saved after the optimization of relevant circulating water pumps.

  11. Study on a constant-tip-speed-ratio operation of wind power generation system. Effect of load control system on dynamic behavior; Furyoku hatsuden system no hensoku seigyo unten ni kansuru kenkyu. Fuka seigyokei ga system no rikigakuteki kyodo ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, T.; Yamaguchi, K. [Waseda University, Tokyo (Japan); Tanzawa, Y. [Nippon Institute of Technology, Saitama (Japan); Hashizume, T.; Ota, E. [Waseda University, Tokyo (Japan). School of Science and Engineering

    1998-06-01

    The effect that the set data of the load control system in a wind power generation system exerts on the dynamic behavior of a system was investigated. The wind power generation system consists of a hybrid wind turbine with combined Darrieus and Savonius rotors, load with a generator and battery in the center, and a controller. A constant-tip-speed ratio operation that holds the circumferential speed ratio in which the power coefficient is maximized irrespective of the change in wind velocity was used to extract and convert the wind energy more effectively. In a high-wind velocity area, the system is operated at a fixed speed, and the increase in rotation is suppressed to protect the wing strength. In a large system, the response characteristics are only slightly improved by the limited load operation range and influenced rotor inertial. Power cannot be fully extracted even if the control system is changed in setting, and the applicability to the wind situation remains low. During the actual operation, the adjustment value of the control system should be set so that the output operation is satisfactorily possible in the specified load operation range, that is, the change in the instantaneous value of an effective power coefficient indicates almost flat gain characteristics in frequency characteristics. 14 refs., 10 figs., 2 tabs.

  12. Speeding Into a New Era

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ A 202-km high-speed railway linking two major Chinese cities was officially put into operation on October 19,the latest landmark in the country's largest railway construction boom. Two bullet trains equipped with China's CRH380A system jumpstarted simultaneously at 9:00 a.m.on October 26 from Hongqiao Station in Shanghai and Hangzhou Station in Zhejiang Province,marking the inaugural run of the Shanghai-Hangzhou highspeed railway.

  13. 40 GW Created "Datang's Speed"

    Institute of Scientific and Technical Information of China (English)

    Huang Yuan; Yang Liu; Ye Qing

    2006-01-01

    @@ As the unit No.1 of Wangtan Power Plant, Hebei Datang International, completed 168-hour trial operation successively and was delivered to operation on December 7th, 2005, the power installed capacity of China Datang Corporation (CDT) reached 40.2496 GW. It indicated CDT, of which the installed capacity breaks 40 GW level, had become the second power generation group in China. In the meantime, it has also been the power generation group with most power units commissioned at a fastest speed since three years of power institutional reform. The yearly commissioned capacity reached 13.6406 GW.

  14. Speed in Acquisitions

    DEFF Research Database (Denmark)

    Meglio, Olimpia; King, David R.; Risberg, Annette

    2017-01-01

    The advantage of speed is often invoked by academics and practitioners as an essential condition during post-acquisition integration, frequently without consideration of the impact earlier decisions have on acquisition speed. In this article, we examine the role speed plays in acquisitions across...... the acquisition process using research organized around characteristics that display complexity with respect to acquisition speed. We incorporate existing research with a process perspective of acquisitions in order to present trade-offs, and consider the influence of both stakeholders and the pre......-deal-completion context on acquisition speed, as well as the organization’s capabilities to facilitating that speed. Observed trade-offs suggest both that acquisition speed often requires longer planning time before an acquisition and that associated decisions require managerial judgement. A framework for improving...

  15. Ship speed optimization: Concepts, models and combined speed-routing scenarios

    DEFF Research Database (Denmark)

    Psaraftis, Harilaos N.; Kontovas, Christos A.

    2014-01-01

    The purpose of this paper is to clarify some important issues as regards ship speed optimization at the operational level and develop models that optimize ship speed for a spectrum of routing scenarios in a single ship setting. The paper's main contribution is the incorporation of those fundament...

  16. 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,

  17. 46 CFR 154.1864 - Vessel speed within speed reduction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vessel speed within speed reduction. 154.1864 Section... Vessel speed within speed reduction. The master shall ensure that the speed of the vessel is not greater than the posted speed reduction....

  18. 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.

  19. 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.

  20. Speed control system for an access gate

    Science.gov (United States)

    Bzorgi, Fariborz M.

    2012-03-20

    An access control apparatus for an access gate. The access gate typically has a rotator that is configured to rotate around a rotator axis at a first variable speed in a forward direction. The access control apparatus may include a transmission that typically has an input element that is operatively connected to the rotator. The input element is generally configured to rotate at an input speed that is proportional to the first variable speed. The transmission typically also has an output element that has an output speed that is higher than the input speed. The input element and the output element may rotate around a common transmission axis. A retardation mechanism may be employed. The retardation mechanism is typically configured to rotate around a retardation mechanism axis. Generally the retardation mechanism is operatively connected to the output element of the transmission and is configured to retard motion of the access gate in the forward direction when the first variable speed is above a control-limit speed. In many embodiments the transmission axis and the retardation mechanism axis are substantially co-axial. Some embodiments include a freewheel/catch mechanism that has an input connection that is operatively connected to the rotator. The input connection may be configured to engage an output connection when the rotator is rotated at the first variable speed in a forward direction and configured for substantially unrestricted rotation when the rotator is rotated in a reverse direction opposite the forward direction. The input element of the transmission is typically operatively connected to the output connection of the freewheel/catch mechanism.

  1. Speed-Selector Guard For Machine Tool

    Science.gov (United States)

    Shakhshir, Roda J.; Valentine, Richard L.

    1992-01-01

    Simple guardplate prevents accidental reversal of direction of rotation or sudden change of speed of lathe, milling machine, or other machine tool. Custom-made for specific machine and control settings. Allows control lever to be placed at only one setting. Operator uses handle to slide guard to engage or disengage control lever. Protects personnel from injury and equipment from damage occurring if speed- or direction-control lever inadvertently placed in wrong position.

  2. 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 ...

  3. Bio-inspired speed detection and discrimination

    OpenAIRE

    Cerda, Mauricio; Terissi, Lucas; Girau, Bernard

    2009-01-01

    International audience; In the field of computer vision, a crucial task is the detection of motion (also called optical flow extraction). This operation allows analysis such as 3D reconstruction, feature tracking, time-to-collision and novelty detection among others. Most of the optical flow extraction techniques work within a finite range of speeds. Usually, the range of detection is extended towards higher speeds by combining some multiscale information in a serial architecture. This serial...

  4. Handbook of asynchronous machines with variable speed

    CERN Document Server

    Razik, Hubert

    2013-01-01

    This handbook deals with the asynchronous machine in its close environment. It was born from a reflection on this electromagnetic converter whose integration in industrial environments takes a wide part. Previously this type of motor operated at fixed speed, from now on it has been integrated more and more in processes at variable speed. For this reason it seemed useful, or necessary, to write a handbook on the various aspects from the motor in itself, via the control and while finishing by the diagnosis aspect. Indeed, an asynchronous motor is used nowadays in industry where variation speed a

  5. Speed enforcement in Norway

    DEFF Research Database (Denmark)

    Elvik, Rune

    2015-01-01

    This paper probes the relationship between changes in the risk of apprehension for speeding in Norway and changes in the amount of speeding. The paper is based on a game-theoretic model of how the rate of violations and the amount of enforcement is determined by the interaction between drivers...

  6. Speed and income

    DEFF Research Database (Denmark)

    Fosgerau, Mogens

    2005-01-01

    between speed and income is found again in the empirical analysis of a cross-sectional dataset comprising 60,000 observations of car trips. This is used to perform regressions of speed on income, distance travelled, and a number of controls. The results are clearly statistically significant and indicate...

  7. Effectiveness of Motorcycle speed controlled by speed hump

    Directory of Open Access Journals (Sweden)

    Pornsiri Urapa

    2014-09-01

    Full Text Available Speed humps are one of the traffic calming measures widely accepted to control vehicle speed in the local road. Humps standards from the western countries are designed mainly for the passenger car. This study, therefore, aims to reveal the effectiveness of speed hump to control the motorcycle speed. This study observes the free-flow speed of the riders at the total of 20 speed bumps and humps. They are 0.3-14.8 meter in width and 5-18 centimeter in height. The results reveal that the 85th percentile speeds reduce 15-65 percent when crossing the speed bumps and speed humps. Besides, this study develops the speed model to predict the motorcycle mean speed and 85th percentile speed. It is found that speed humps follow the ITE standard can control motorcycle crossing speeds to be 25-30 Kph which are suitable to travel on the local road.

  8. 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.

  9. Traffic speed management

    Directory of Open Access Journals (Sweden)

    Subotić Jovana Lj.

    2014-01-01

    Full Text Available Speed, and vehicles themselves, affect the level of service and road safety, quality of life, noise from traffic, the environment, health, air pollution, emission of carbon dioxide, global warming, the economy and consumption of non-renewable energy such as oil. Therefore, the speed management of the traffic of multiple significance and that should be primarily to provide effective and economical conditions of the modern and preventive protection of human life as the greatest treasure and then the material resources. The way to accomplish this is by using various (different measures such as: appropriate planning and projecting roads and streets, speed control, the legislation, enforcement, campaigns, education, advanced technologies (ITS.

  10. Gas speed flow transducer

    Directory of Open Access Journals (Sweden)

    Godovaniouk V. N.

    2011-08-01

    Full Text Available The design of a gas speed flow transducer using the coupling of gas speed and heat streams within the transducer itself is proposed. To maintain the heat balance between two thermoresistors under gas stream at different temperatures, it provides energy consumption monitoring. The detailed combined planar technology for the transducer production is presented. The worked-out measurement procedure allows to make measurements in the temperature range. Information enough to organize production of cheap, reliable and precise gas speed flow transducers is given.

  11. 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.

  12. Speed estimator for induction motor drive based on synchronous speed tracking

    Indian Academy of Sciences (India)

    S B Bodkhe; M V Aware; J G Chaudhari; J G Agrawal

    2015-06-01

    This paper presents a new open-loop speed estimation method for a three-phase induction motor drive. The open-loop speed estimators available in literature have the advantage of reduced computational stress over the observers but they share a common limitation of being largely dependent on flux and machine parameters. They involve integrations and differentiation in the algorithm that leads to serious error in estimation when subject to different operating conditions. The proposed estimator is based on synchronous speed tracking and is cost-effective. It is immune to any variation in machine parameters and noise. The synchronous speed is computed from stator frequency which is estimated on-line using the stator current signals. A unique, non-adaptive method for estimation of stator frequency within one-sixteenth of time period is also proposed to enhance the speed of estimation. Computer simulation and experimentation on a 2.2 kW Field oriented controlled induction motor drive is carried out to verify the performance of proposed speed estimator. The results show excellent response over a wide range of rotor speed in both directions including low speed and under different operating conditions. This confirms the effectiveness of the proposed method.

  13. Wind_Speeds_Master

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set included wind speeds for each subregion in the study (Georges Bank, Gulf of Maine, Southern New England, Middle Atlantic Bight) . The data came from...

  14. Speeding up Transportation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 2007 was an excellent year for the transportation industry, marked by high speed railway transportation, development of the national expressway network and launch of the Chang'e lunar probe satellite.

  15. 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.

  16. DEVELOPMENT OF THE COMPLEX-ALLOYED STEEL OF INCREASED HARDENABILITY, VISCOSITY AND HEAT-RESISTANCE FOR CUTTING PARTS OF HIGH-SPEED INSTRUMENT, OPERATING IN CONDITIONS OF HEATING UP AND DYNAMIC LOADS

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2006-01-01

    Full Text Available The theoretical aspects of development of the complex-alloyed steel compounds for cutting parts of high-speed instrument, particularly influence of alloying elements on its structure and characteristics are considered. It is shown that combined alloying of steel by carbon, chrome, silicon, manganese, vanadium and molybdenum in a certain proportion allows to reach the intended aim, achieving at the same time increase of solidity, impact elasticity and heat stability.

  17. Police enforcement and driving speed.

    NARCIS (Netherlands)

    2008-01-01

    Speed limits are violated frequently in the Netherlands. As speed is an important factor in road crashes, the surveillance of driving speeds is one of the spearheads in the policy plans of the Dutch police. Different methods of speed enforcement have proved to be effective in reducing speed and cras

  18. Calculating Speed of Sound

    Science.gov (United States)

    Bhatnagar, Shalabh

    2017-01-01

    Sound is an emerging source of renewable energy but it has some limitations. The main limitation is, the amount of energy that can be extracted from sound is very less and that is because of the velocity of the sound. The velocity of sound changes as per medium. If we could increase the velocity of the sound in a medium we would be probably able to extract more amount of energy from sound and will be able to transfer it at a higher rate. To increase the velocity of sound we should know the speed of sound. If we go by the theory of classic mechanics speed is the distance travelled by a particle divided by time whereas velocity is the displacement of particle divided by time. The speed of sound in dry air at 20 °C (68 °F) is considered to be 343.2 meters per second and it won't be wrong in saying that 342.2 meters is the velocity of sound not the speed as it's the displacement of the sound not the total distance sound wave covered. Sound travels in the form of mechanical wave, so while calculating the speed of sound the whole path of wave should be considered not just the distance traveled by sound. In this paper I would like to focus on calculating the actual speed of sound wave which can help us to extract more energy and make sound travel with faster velocity.

  19. Torque- and Speed Control of a Pitch Regulated Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rasila, Mika

    2003-07-01

    Variable speed operated wind turbines has the potential to reduce fatigue loads, compared to fixed speed wind turbines. With pitch controllable rotor blades limitation of the power at high wind speeds is obtained. The thesis describes different controlling aspects concerning wind turbines and how these together can be used to optimize the system's performance. Torque control is used in order to achieve reduction on the mechanical loads on the drive-train for low wind speeds and limitation of power output for high wind speeds. In the high wind speed interval torque control is effective in order to limit the output power if a sufficiently fast pitch actuator is used. In the middle wind speed interval filter utilization can be used to give a reference signal to the controller in order to reduce speed and torque variations.

  20. Efficient Method for Improving the Reliability of Decentralized Operation Control System of High-speed Maglev Train%高速磁浮列车分区运行控制系统可靠性提高方法研究

    Institute of Scientific and Technical Information of China (English)

    周鹏; 徐洪泽

    2011-01-01

    The decentralized operation control system is a kind of safety-critical computer control system, which realizes the function of operation command and safety protection for high-speed maglev trains. On the basis of the experience of developing, debugging and running the engineering prototype of the decentralized operation control system on the 1. 5km high-speed maglev experimental railway line, the status collection model was set up. Based on the model, an efficient method for improving reliability was proposed. The feasibility of the method was proved. At last, the method was applied in the decentralized operation control system, and the reliability of the high-speed maglev train operation control system was improved efficiently, which is useful to nationalize the high-speed maglev decentralized operation control system.%分区运行控制系统是实现高速磁浮列车运行指挥及安全防护的安全苛求计算机控制系统.本文借鉴上海同济大学1.5km高速磁浮列车试验线的分区运行控制系统工程样机研制与现场运行调试经验,建立状态回采模型.基于该模型提出一套适用于高速磁浮列车分区运行控制系统软件的可靠性提高方法:状态回采法,并从理论上证明了这种方法的可行性,最终将该方法运用于分区运行控制系统,提高了其可靠性,为高速磁浮列车分区控制系统的国产化工作提供了技术支持.

  1. 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.

  2. A New Simple Ultrahigh Speed Decoding Algorithm for BCH Code

    Institute of Scientific and Technical Information of China (English)

    唐建军; 纪越峰

    2002-01-01

    In order to content with forward error correction (FEC) technology of the high-speed optical communication system, a new simple decoding algorithm for triple-error correcting Bose, Chaudhuri, and Hocquenghem (BCH) code is proposed. Without complicated matrix-operation or division-operation or intricate iterative algorithm, the algorithm is high efficient and high-speed because of its simplicity in structure. The result of hardware emulation confirms that the algorithm is feasible completely. Introduction of the parallel structure increases the speed of coding greatly. The algorithm can be used in the high-speed optical communication system and other fields.

  3. 14 CFR 25.1583 - Operating limitations.

    Science.gov (United States)

    2010-01-01

    ... or pilot training. (2) If an airspeed limitation is based upon compressibility effects, a statement... engine powers. (5) The landing gear operating speed or speeds, and a statement explaining the speeds as defined in § 25.1515(a). (6) The landing gear extended speed V LE, if greater than V LO, and a...

  4. Variable Speed Rotor System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Variable speed rotors will give helicopters several advantages: higher top speed, greater fuel efficiency, momentary emergency over-power, resonance detuning...

  5. 跨境电商全球速卖通平台店铺运营分析与实践%Analysis and practice of cross-border electronic business store operation on global speed-selling platform

    Institute of Scientific and Technical Information of China (English)

    刘世鹏; 张欣雨

    2016-01-01

    With the improvement of global e-commerce system, the emergence of global speed-selling platform provides a new carrier and path for cross-border electronic business. In order to adapt to the characteristics of electronic commerce, internationalization and interconnection, cross-border electronic merchants should make full use of the global speed-selling platform to speed up the flattening of cross-border electronic business transactions, automation of the process, and promote the change and innovation process from the aspects of logistics, talents and trade, so as to make the effective support and active adaptation for the development of cross-border electronic business.%在全球电子商务体系逐步完善的今天,全球速卖通平台的出现为跨境电商提供了新的载体和路径。为了顺应商务电子化、国际化和互联互通的时代特点,跨境电商要更好地运用全球速卖通平台,以店铺运营作为中心,加速跨境电商交易的扁平化、流程的自动化,从物流、人才、交易等各个层面推进变革与创新的进程,达到对跨境电商发展的有效支持和积极适应。

  6. On Hamiltonians Generating Optimal-Speed Evolutions

    OpenAIRE

    2008-01-01

    We present a simple derivation of the formula for the Hamiltonian operator(s) that achieve the fastest possible unitary evolution between given initial and final states. We discuss how this formula is modified in pseudo-Hermitian quantum mechanics and provide an explicit expression for the most general optimal-speed quasi-Hermitian Hamiltonian. Our approach allows for an explicit description of the metric- (inner product-) dependence of the lower bound on the travel time and the universality ...

  7. A conceptual framework for evaluating variable speed generator options for wind energy applications

    Science.gov (United States)

    Reddoch, T. W.; Lipo, T. A.; Hinrichsen, E. N.; Hudson, T. L.; Thomas, R. J.

    1995-01-01

    Interest in variable speed generating technology has accelerated as greater emphasis on overall efficiency and superior dynamic and control properties in wind-electric generating systems are sought. This paper reviews variable speed technology options providing advantages and disadvantages of each. Furthermore, the dynamic properties of variable speed systems are contrasted with synchronous operation. Finally, control properties of variable speed systems are examined.

  8. PERSONALITY AND SPEEDING

    Directory of Open Access Journals (Sweden)

    Richard TAY

    2003-01-01

    Full Text Available While there has been extensive research on the effect of sensation seeking on risky driving, relatively little research has been conducted on Type-A personality. The motivations for speeding are likely to be different for each group and these differences have important implications for the design, implementation and expected efficacy of road safety countermeasures. This paper examines the influence of sensation seeking and Type-A behavior pattern on speeding behaviour. A sample of 139 staff and students in an Australian university were surveyed in July 2001 to gather information on their gender, age, personality and self-reported speeding behaviour. The data were analysed using correlations and analysis of variance procedures. Finally, some implications for road safety are discussed.

  9. Ship speed optimization: Concepts, models and combined speed-routing scenarios

    DEFF Research Database (Denmark)

    Psaraftis, Harilaos N.; Kontovas, Christos A.

    2014-01-01

    The purpose of this paper is to clarify some important issues as regards ship speed optimization at the operational level and develop models that optimize ship speed for a spectrum of routing scenarios in a single ship setting. The paper's main contribution is the incorporation of those fundamental...... parameters and other considerations that weigh heavily in a ship owner's or charterer's speed decision and in his routing decision, wherever relevant. Various examples are given so as to illustrate the properties of the optimal solution and the various trade-offs that are involved....

  10. Electromagnetic Operation Environment Analysis of Middle-low-speed Maglev Train%中低速磁悬浮列车运行电磁环境的分析

    Institute of Scientific and Technical Information of China (English)

    齐洪峰

    2012-01-01

    With electromagnetic finite element method, leakage magnetic field distribution of electromagnets and linear traction motor was simulated and calculated, the results of which were compared to test reports of electromagnetic radiation field of CMS04 middle-low-speed maglev train carried out by Institute of Electrical Engineering Chinese Academy of Science, which proved that middle-low-speed maglev train transport system was a kind of green urban rail transit system with good electromagnetic environment.%采用电磁场有限元法对悬浮电磁铁和直线牵引电机的泄漏磁场分布进行仿真计算,并将计算结果与中国科学院电工所对CMS04型中低速磁悬浮列车电磁辐射现场测试报告进行详实的比较分析,从而证明了中低速磁悬浮列车交通系统是一种电磁环境良好的绿色城市轨道交通系统.

  11. 基于CCD的自主机器人高速运行控制算法设计%Design of high-speed operation control algorithm for autonomous robot based on CCD

    Institute of Scientific and Technical Information of China (English)

    姚世选; 李秋宝; 王剑新; 康相玖; 仲崇权

    2013-01-01

    基于特定的机械结构和电气特性的单目CCD轮式机器人,提出一种高速控制算法,使机器人发挥最优速度潜能.该算法采用图像定位模型,根据当前机器人的位置信息,模拟可能的转向角下的运行轨迹,参考规则数据库,给出最优偏转角度和速度控制决策.实验研究表明:该算法具有较好的可行性.%A high-speed control algorithm is put forward to make the monocular CCD wheeled robot which is based on specific mechanical structure and electric properties play the best velocity potential. The algorithm adopts image positioning model, simulates running track in possible steering angle according to the current location information of the robot and referring to rule database to provide optimal deflection angle and speed control decision. Experimental research shows that the algorithm has good feasibility.

  12. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  13. Variable-Speed Wind System Design : Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Lauw, Hinan K.; Weigand, Claus H.; Marckx, Dallas A.; Electronic Power Conditioning, Inc.

    1993-10-01

    Almost from the onset of the development of wind energy conversion systems (WECS), it was known that variable-speed operation of the turbine would maximize energy capture. This study was commissioned to assess the cost, efficiency gain, reduction of the cost of energy (COE), and other operating implications of converting the existing hardware of a modern fixed-speed wind energy conversion system to variable-speed operation. The purpose of this study was to develop a preliminary design for the hardware required to allow variable-speed operation using a doubly-fed generator with an existing fixed-speed wind turbine design. The turbine selected for this study is the AWT-26 designed and built by Advanced Wind Turbines Inc. of Redmond, Washington. The lowest projected COE using this variable-speed generation system is projected to be $0.0499/kWh, compared to the lowest possible COE with fixed-speed generation which is projected to be $0.0546/kWh. This translates into a 8.6% reduction of the COE using this variable-speed generation option. The preliminary system design has advanced to where the printed circuit boards can be physically laid out based on the schematics and the system software can be written based on the control flow-charts. The core of hardware and software has been proven to be successful in earlier versions of VSG systems. The body of this report presents the results of the VSWG system development. Operation under normal and fault conditions is described in detail, the system performance for variable-speed operation is estimated and compared to the original fixed-speed system performance, and specifications for all system components (generator, power electronic converter, and system controller) are given. Costs for all components are estimated, and incremental system cost is compared to incremental energy production. Finally, operational features of the VSWG which are not available in the existing FSWG system are outlined.

  14. Spindle picker harvest speed effects

    Science.gov (United States)

    The gear drive of a modern John Deere Pro 16 picker unit was modified so that spindle speed was reduced without changing the drum speed. Three 1-row picking units were used in the study, one with the standard drive speeds, one with 25% reduction in spindle drive speed, and one with 50% reduction in...

  15. Speeding Up Innovation

    DEFF Research Database (Denmark)

    Sørensen, Flemming; Mattsson, Jan

    2016-01-01

    Minimisation of time-to-market strategies can provide companies with a competitive advantage in dynamic and competitive environments. Using parallel innovation processes has been emphasised as one strategy to speed up innovation processes and consequently minimise the time-to-market of innovations...

  16. More Than Just Speed

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Following more than 10 years of deliberation and planning,construc- tion of the 1,320-km Beijing-Shanghai High-speed Railway began in mid- April.Following the world’s most elevated Qinghai-Tibet Railway,which

  17. Variable speed generators

    CERN Document Server

    Boldea, Ion

    2005-01-01

    With the deregulation of electrical energy production and distribution, says Boldea (Polytechnical Institute, Timisoara, Romania) producers are looking for ways to tailor their electricity for different markets. Variable-speed electric generators are serving that purpose, up to the 400 megavolt ampere unit size, in Japan since 1996 and Germany sinc

  18. Cloud speed sensor

    Directory of Open Access Journals (Sweden)

    V. Fung

    2013-10-01

    Full Text Available Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system that measures cloud motion vectors to estimate power plant ramp rates and provide short term solar irradiance forecasts is presented. The Cloud Speed Sensor (CSS is constructed using an array of luminance sensors and high-speed data acquisition to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground measured irradiance (Linear Cloud Edge, LCE, and a UC San Diego Sky Imager (USI. The CSS detected artificial shadow directions and speeds to within 15 and 6% accuracy, respectively. The CSS detected (real cloud directions and speeds without average bias and with average weighted root mean square difference of 22° and 1.9 m s−1 when compared to USI and 33° and 1.5 m s−1 when compared to LCE results.

  19. Speed mathematics simplified

    CERN Document Server

    Stoddard, Edward

    1994-01-01

    Entertaining, easy-to-follow suggestions for developing greater speed and accuracy in doing mathematical calculations. Surefire methods for multiplying without carrying, dividing with half the pencil work of long division, plus advice on how to add and subtract rapidly, master fractions, work quickly with decimals, handle percentages, and much more.

  20. Future ultra-speed tube-flight

    Science.gov (United States)

    Salter, Robert M.

    1994-05-01

    Future long-link, ultra-speed, surface transport systems will require electromagnetically (EM) driven and restrained vehicles operating under reduced-atmosphere in very straight tubes. Such tube-flight trains will be safe, energy conservative, pollution-free, and in a protected environment. Hypersonic (and even hyperballistic) speeds are theoretically achievable. Ultimate system choices will represent tradeoffs between amoritized capital costs (ACC) and operating costs. For example, long coasting links might employ aerodynamic lift coupled with EM restraint and drag make-up. Optimized, combined EM lift, and thrust vectors could reduce energy costs but at increased ACC. (Repulsive levitation can produce lift-over-drag l/d ratios a decade greater than aerodynamic), Alternatively, vehicle-emanated, induced-mirror fields in a conducting (aluminum sheet) road bed could reduce ACC but at substantial energy costs. Ultra-speed tube flight will demand fast-acting, high-precision sensors and computerized magnetic shimming. This same control system can maintain a magnetic 'guide way' invariant in inertial space with inertial detectors imbedded in tube structures to sense and correct for earth tremors. Ultra-speed tube flight can complete with aircraft for transit time and can provide even greater passenger convenience by single-model connections with local subways and feeder lines. Although cargo transport generally will not need to be performed at ultra speeds, such speeds may well be desirable for high throughput to optimize channel costs. Thus, a large and expensive pipeline might be replaced with small EM-driven pallets at high speeds.

  1. Short-term wind speed estimation based on weather data

    OpenAIRE

    ÖZGÖNENEL, Okan; THOMAS, David W. P.

    2012-01-01

    For accurate and efficient use of wind power, it is important to know the statistical characteristics, availability, diurnal variation, and prediction of wind speed. Prediction of wind power permits the scheduling of the connection or the disconnection of wind turbines to achieve optimal operating costs. In this paper, a simple and accurate method for predicting wind speed based on weather-sensitive data is presented. The proposed wind speed prediction system is cost-effective and o...

  2. Maritime routing and speed optimization with emission control areas

    DEFF Research Database (Denmark)

    Fagerholt, Kjetil; Gausel, Nora T.; Rakke, Jørgen G.;

    2015-01-01

    minimizing their costs, it is likely that speed and routing decisions will change because of this. In this paper, we develop an optimization model to be applied by ship operators for determining sailing paths and speeds that minimize operating costs for a ship along a given sequence of ports. We perform...... a computational study on a number of realistic shipping routes in order to evaluate possible impacts on sailing paths and speeds, and hence fuel consumption and costs, from the ECA regulations. Moreover, the aim is to examine the implications for the society with regards to environmental effects. Comparisons...... of cases show that a likely effect of the regulations is that ship operators will often choose to sail longer distances to avoid sailing time within ECAs. Another effect is that they will sail at lower speeds within and higher speeds outside the ECAs in order to use less of the more expensive fuel. On some...

  3. 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.

  4. 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.

  5. Improving speed behaviour : the potential of in-car speed assistance and speed limit credibility.

    NARCIS (Netherlands)

    Nes, C.N. van Houtenbos, M. & Schagen, I.N.L.G. van

    2009-01-01

    Speeding is still a common practice on many roads and it contributes to a significant number of crashes. Two new approaches to solve speeding issues are focused on: intelligent speed assistance systems (ISA) and speed limit credibility. Research has indicated that ISA is promising with respect to im

  6. Speed Control and Coiling Temperature Control of Strip

    Institute of Scientific and Technical Information of China (English)

    CAI Xiao-hui; ZHANG Dian-hua; WANG Guo-dong; LIU Xiang-hua; FAN Lei

    2004-01-01

    Considering the strip speed during controlled laminar cooling on Baosteel 1580 hot strip mill in China, the influence of strip speed fluctuation on coiling temperature control for the tail and "neck" of the strip was analyzed. The optimization strategies were put forward and proved effective in operation.

  7. Optical correlators with fast updating speed using photorefractive semiconductor materials

    Science.gov (United States)

    Gheen, Gregory; Cheng, Li-Jen

    1988-01-01

    The performance of an updatable optical correlator which uses a photorefractive semiconductor to generate real-time matched filters is discussed. The application of compound semiconductors makes possible high-speed operation and low optical input intensities. The Bragg diffraction is considered, along with the speed and power characteristics of these materials. Experimental results on photorefractive GaAs are presented.

  8. Speed Rotating Components

    Directory of Open Access Journals (Sweden)

    S. Wittig

    1998-01-01

    Full Text Available Cooling of high speed rotating components is a typical situation found in turbomachinery as well as in automobile engines. Accurate knowledge of discharge coefficients and heat transfer of related components is essential for the high performance of the whole engine. This can be achieved by minimized cooling air flows and avoidance of hot spots. In high speed rotating clutches for example aerodynamic investigations improving heat transfer have not been considered in the past. Advanced concepts of modern plate design try to reduce thermal loads by convective cooling methods. Therefore, secondary cooling air flows have to be enhanced by an appropriate design of the rotor stator system with orifices. CFD modelling is used to improve the basic understanding of the flow field in typical geometries used in these systems.

  9. Forecasting Solar Wind Speeds

    CERN Document Server

    Suzuki, T K

    2006-01-01

    By explicitly taking into account effects of Alfven waves, I derive from a simple energetics argument a fundamental relation which predicts solar wind (SW) speeds in the vicinity of the earth from physical properties on the sun. Kojima et al. recently found from their observations that a ratio of surface magnetic field strength to an expansion factor of open magnetic flux tubes is a good indicator of the SW speed. I show by using the derived relation that this nice correlation is an evidence of the Alfven wave which accelerates SW in expanding flux tubes. The observations further require that fluctuation amplitudes of magnetic field lines at the surface should be almost universal in different coronal holes, which needs to be tested by future observations.

  10. Monitoring speed before and during a speed publicity campaign.

    Science.gov (United States)

    van Schagen, Ingrid; Commandeur, Jacques J F; Goldenbeld, Charles; Stipdonk, Henk

    2016-12-01

    Driving speeds were monitored during a period of 16 weeks encompassing different stages of an anti-speeding campaign in the Netherlands. This campaign targeted speed limit violations in built-up areas. The observation periods differed in terms of intensity and media used for the campaign. Small road-side radars, mounted in light poles, were used and registered the speeds on 20 locations in built-up areas. Speeds of over 10 million vehicles were measured. Ten locations had a posted speed limit of 50km/h; the other ten had a posted speed limit of 30km/h. Posters were placed at half of each group of locations to remind drivers of the speed limit. The average speed on the 50km/h roads was 46.2km/h, and 36.1km/h on the 30km/h roads. The average proportions of vehicles exceeding the speed limit were 33.3% and 70.1% respectively. For the 30km/h roads, the data shows differences in speed and speeding behaviour between the six distinguished observation periods, but overall these differences cannot be logically linked to the contents of the phases and, hence, cannot be explained as an effect of the campaign. The only exception was an effect of local speed limit reminders on the 30km/h roads. This effect, however, was temporary and had disappeared within a week.

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. Improved Rotor Speed Brushless DC Motor using Fuzzy Controller

    OpenAIRE

    Jafar Mostafapour; Murtaza Farsadi; Ali Badri; Ebrahim Ogabi

    2016-01-01

    A brushless DC (BLDC) Motors have advantages over brushed, direct current (DC) motors and Induction motor (IM). They have better speed verses torque characteristics, high dynamic response, high efficiency, long operating life, noiseless operation, higher speed ranges, and rugged construction. Also, torque delivered to motor size is higher, making it useful in application where space and weight are critical factors. With these advantages BLDC motors find wide spread application in automotive a...

  16. Improved Rotor Speed Brushless DC Motor Using Fuzzy Controller

    OpenAIRE

    Jafar Mostafapour; Jafar Reshadat; Murtaza Farsadi

    2015-01-01

    A brushless DC (BLDC) Motors have advantages over brushed, Direct current (DC) Motors and , Induction motor (IM). They have better speed verses torque characteristics, high dynamic response, high efficiency, long operating life, noiseless operation, higher speed ranges, and rugged construction. Also, torque delivered to motor size is higher, making it useful in application where space and weight are critical factors. With these advantages BLDC motors find wide spread application in automotive...

  17. 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....

  18. Anchor handling tug operations: a practical guide to the operation of modern anchor handling tugs engaged in anchor handling and towing operations

    National Research Council Canada - National Science Library

    Clark, I.C; Hancox, M

    2012-01-01

    ... --Turning and manoeuvring modern anchor handling vessels --The AHTS design and towing operations --The dangers of very high speed loads during deep water anchor handling operations --The dangers...

  19. Operation Anaconda. Lessons for Joint Operations

    Science.gov (United States)

    2009-03-01

    joint battle plan and commanded accordingly. For all services, fast-paced joint operations in the information era require well-honed skills that...communications. Accompanying Lessons: To carry out information - era operations, excellent joint communications at all levels are vital, as are...to employ their information - era assets to full advantage. 39 Accompanying Lessons: Modern combat requires great skill and high-speed

  20. Pay as You Speed, ISA with incentives for not speeding

    DEFF Research Database (Denmark)

    Lahrmann, Harry; Agerholm, Niels; Tradisauskas, Nerius

    2012-01-01

    The Intelligent Speed Adaptation (ISA) project we describe in this article is based on Pay as You Drive principles. These principles assume that the ISA equipment informs a driver of the speed limit, warns the driver when speeding and calculates penalty points. Each penalty point entails the redu...

  1. Monitoring speed before and during a speed publicity campaign.

    NARCIS (Netherlands)

    Schagen, I.N.L.G. van Commandeur, J.J.F. Goldenbeld, C. & Stipdonk, H.

    2016-01-01

    Driving speeds were monitored during a period of 16 weeks encompassing different stages of an anti-speeding campaign in the Netherlands. This campaign targeted speed limit violations in built-up areas. The observation periods differed in terms of intensity and media used for the campaign. Small road

  2. The role of visual processing speed in reading speed development.

    Directory of Open Access Journals (Sweden)

    Muriel Lobier

    Full Text Available A steady increase in reading speed is the hallmark of normal reading acquisition. However, little is known of the influence of visual attention capacity on children's reading speed. The number of distinct visual elements that can be simultaneously processed at a glance (dubbed the visual attention span, predicts single-word reading speed in both normal reading and dyslexic children. However, the exact processes that account for the relationship between the visual attention span and reading speed remain to be specified. We used the Theory of Visual Attention to estimate visual processing speed and visual short-term memory capacity from a multiple letter report task in eight and nine year old children. The visual attention span and text reading speed were also assessed. Results showed that visual processing speed and visual short term memory capacity predicted the visual attention span. Furthermore, visual processing speed predicted reading speed, but visual short term memory capacity did not. Finally, the visual attention span mediated the effect of visual processing speed on reading speed. These results suggest that visual attention capacity could constrain reading speed in elementary school children.

  3. Variable-speed Generators with Flux Weakening

    Science.gov (United States)

    Fardoun, A. A.; Fuchs, E. F.; Carlin, P. W.

    1993-01-01

    A cost-competitive, permanent-magnet 20 kW generator is designed such that the following criteria are satisfied: an (over) load capability of at least 30 kW over the entire speed range of 60-120 rpm, generator weight of about 550 lbs with a maximum radial stator flux density of 0.82 T at low speed, unity power factor operation, acceptably small synchronous reactances and operation without a gear box. To justify this final design four different generator designs are investigated: the first two designs are studied to obtain a speed range from 20 to 200 rpm employing rotor field weakening, and the latter two are investigated to obtain a maximum speed range of 40 to 160 rpm based on field weakening via the stator excitation. The generator reactances and induced voltages are computed using finite element/difference solutions. Generator losses and efficiencies are presented for all four designs at rated temperature of Tr=120C.

  4. A Method for Wind Power Calculation Considering Wind Speed Spatial and Temporal Distribution and Wind Turbine Operation Status%考虑风速时空分布及风机运行状态的风电场功率计算方法

    Institute of Scientific and Technical Information of China (English)

    孙辉; 徐箭; 孙元章; 雷若冰

    2015-01-01

    In the background of large-scale wind power connected to the grid,accurately calculating the output power of the wind farm is of utmost importance to the dispatching control and grid safe operation.By taking the mean wind speed and direction measured by masts on the minute-to-hour time horizon level as the inputs,the impact of the geographical distribution of wind turbine and wind turbine commitment on the wake model is studied.A new equivalent wind speed model is proposed according to the wind speed spatial and temporal distribution on the wind farm.Based on the proposed wind speed model,a method for wind power calculation considering the mechanical characteristics and operation status of wind turbines is presented. The feasibility and rationality of the method proposed are verified by simulation results of an actual wind farm”s geographical data and wind turbine parameters.%大规模风电并网背景下,准确计算风电场输出功率对调度控制和电网安全运行至关重要。以区域内测风塔观测的分钟到小时级平均风速和风向为输入,研究风机地理分布以及风机启停对尾流模型的影响,计及风速在空间分布的时延效应,建立了考虑风速时空分布特性的等效风速模型。在此基础上,进一步考虑风机的机械特性及运行状态,提出了风电场功率计算方法。以某实际风电场地理数据和风机参数为基础的仿真算例验证了所提方法的可行性和合理性。

  5. The speed of a cyclist

    Science.gov (United States)

    Hennekam, Wim

    1990-05-01

    The author illustrates an interesting application of physics teaching. The effect of a few laws of mechanics on bicycle speed are examined, and some improvements to increase bicycle speed are considered.

  6. Indirect sensorless speed control of a PMSG for wind application

    DEFF Research Database (Denmark)

    Diaz, S.A.; Silva, C.; Juliet, J.

    2009-01-01

    the method usually referred in the literature as indirect speed control (ISC). The principle of this method is the regulation of the generator torque as function of rotor speed such that the steady state operation is at the MPPT. This strategy normally requires the knowledge of the shaft speed to determinate...... in the whole wind generator system a sensorless scheme is proposed, thereby avoiding problems of electromagnetic interferences and failures in the position sensor. Usually, in wind drive system, the generator is not operated a very low speeds, therefore problems related to low back-emf for flux estimation...... by a squirrel cage induction machine used as wind turbine emulator and the permanent magnet generator. A control program uses a simulated wind profile and gives the speed reference for the induction machine drive, considering the turbine torque production and the inertia of the system. Experimental results...

  7. Improved Rotor Speed Brushless DC Motor using Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    Jafar Mostafapour

    2016-03-01

    Full Text Available A brushless DC (BLDC Motors have advantages over brushed, direct current (DC motors and Induction motor (IM. They have better speed verses torque characteristics, high dynamic response, high efficiency, long operating life, noiseless operation, higher speed ranges, and rugged construction. Also, torque delivered to motor size is higher, making it useful in application where space and weight are critical factors. With these advantages BLDC motors find wide spread application in automotive appliance, aerospace medical, and instrumentation and automation industries This paper can be seen as fuzzy controllers compared to PI control BLDC motor rotor speed has improved significantly and better result can be achieve.

  8. Improved Rotor Speed Brushless DC Motor Using Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    Jafar Mostafapour

    2015-04-01

    Full Text Available A brushless DC (BLDC Motors have advantages over brushed, Direct current (DC Motors and , Induction motor (IM. They have better speed verses torque characteristics, high dynamic response, high efficiency, long operating life, noiseless operation, higher speed ranges, and rugged construction. Also, torque delivered to motor size is higher, making it useful in application where space and weight are critical factors. With these advantages BLDC motors find wide spread application in automotive appliance, aerospace medical, and instrumentation and automation industries This paper can be seen as fuzzy controllers compared to PI control BLDC motor rotor speed has improved significantly and beter result can be achieve.

  9. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Hu, Weihao; Zhang, Yunqian; Chen, Zhe;

    2013-01-01

    Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG...

  10. The Optimum Speed Limit.

    Science.gov (United States)

    1981-05-01

    time eases the interpretation: U2 Lx -4-- where VT is the value of time (dollars (1975) per hour) V is the value of a life (dollars (1975) per L person...that for an individual, the optimal speed depends positively on his value of time and negatively on his valuation of his own life, his subjective...turn to equation (1) once again and solve for the ratio of the value of a life to the value of time , or 1 P s 2 GaS VL SP VT VT az as Rearranging

  11. 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.

  12. 网络信息加密RSA算法的运算速度和保密性优化%Optimization of Operation Speed and Confidentiality of Network Information Encryption RSA Algorithm

    Institute of Scientific and Technical Information of China (English)

    许柯; 刘绪崇; 符振艾; 徐宇宏

    2015-01-01

    According to traditional RSA algorithm has low speed of computing and bad encryption result for encrypting the network information, this article puts forward the RSA encryption algorithm of network information with relevant improved SMM algorithm. The first step is to optimize the modulus and multiplication time of SMM algorithm, the second step is to use the improved SMM algorithm to optimize the RSA algorithm, aiming at the modified algorithm of binary hamming weight in the index, the purpose is to reduce the iteration number, eventually improve the encryption of original algorithm. Seen from the algorithm simulation results, compared with SMM algorithm, the proposed RSA network information encryption algorithm based on improved SMM algorithm and traditional RSA encryption algorithm has faster process of encryption and decryption, and has stronger encryption effect.%针对传统RSA算法在对网络信息进行加密的时候还存在运算速度不快、加密效果不好的问题,本文提出有关改进SMM算法的RSA网络信息加密算法,第一步是针对SMM算法的求模运算量以及乘法时间进行优化操作,第二步是使用改进的SMM算法对RSA算法进行优化,针对其算法的二进制指数中的汉明重量进行改良,目的是为了减少迭代数,最终提升原来算法的加密功能。通过算法仿真实验结果可以看出,本文提出的基于改进SMM算法的RSA网络信息加密算法以及传统RSA加密算法,再与SMM算法进行比较,加密以及解密过程的速度更快,并且加密效果更强。

  13. Guidelines for setting speed limits

    CSIR Research Space (South Africa)

    Wium, DJW

    1986-02-01

    Full Text Available A method is described for setting the speed limit for a particular road section. Several speed limits based on different criteria are described for each of nine traffic and road factors. The most appropriate speed limit for each relevant factor...

  14. Processing at the Speed of Light

    Science.gov (United States)

    2003-01-01

    Spatial Light Modulators (SLMs) are critical elements in optical processing systems used for imaging, displaying, data storage, communications, and other applications. By taking advantage of the natural properties of light beams, the devices process information at speeds unattainable by human operators and most machines, with high-resolution results.Boulder Nonlinear Systems, Inc., is one of the world s foremost SLM manufacturers. Applications of this technology are briefly described.

  15. Speed and position sensors for electric motors

    Energy Technology Data Exchange (ETDEWEB)

    Lyyjynen, M. [Helsinki University of Technology, Otaniemi (Finland). Institute of Intelligent Power Electronics

    1997-12-31

    This paper gives an overview of speed and position measuring instruments for electric motors. The emphasis is on sensors that are designed to operate at industrial environment. In addition to that, some other, mostly magnetic sensors which are used, e.g., in automotive applications, are presented. Some of them are already applied in induction motors and some might be worth a try remembering the limitations. Automotive sensors are very cost-effective due to high production volumes. (orig.) 22 refs.

  16. Resonant speed meter for gravitational wave detection

    CERN Document Server

    Nishizawa, Atsushi; Sakagami, Masa-aki

    2008-01-01

    Gravitational-wave detectors have been well developed and operated with high sensitivity. However, they still suffer from mirror displacement noise. In this paper, we propose a resonant speed meter, as a displacement noise-canceled configuration based on a ring-shaped synchronous recycling interferometer. The remarkable feature of this interferometer is that, at certain frequencies, gravitational-wave signals are amplified, while displacement noises are not.

  17. Design, manufacture and construction of a compressor test rig and the start of experimental operation of a low speed axial compressor at Dresden. Final report; Konstruktion, Fertigung und Aufbau eines Verdichterpruefstandes und Aufnahme des Versuchsbetriebes an einem Niedergeschwindigkeits-Axialverdichter in Dresden. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, W.; Bernhard, H.; Biesinger, T.; Boos, P.; Moeckel, H.; Sauer, H.

    1996-12-01

    In this report, the design, manufacture and construction of the low speed compressor, the build-up of the compressor test rig and the measurement technique used are described. The first measured results obtained after setting to work and the start of experimental operation on the rotational symmetry at the compressor inlet and outlet and of a flow field behind the rotor and stator of the third stage are described. The operating period of 540 hours to the end of the subject shows faultfree operation of the experimental plant. (orig./AKF) [Deutsch] Im vorliegenden Bericht werden Konstruktion, Fertigung und Aufbau des Niedergeschwindigkeitsverdichters, der Aufbau des Verdichterpruefstandes und die verwendete Messtechnik beschrieben. Die nach der Inbetriebnahme und Aufnahme des Versuchsbetriebes erhaltenen ersten Messergebnisse zur Rotationssymmetrie am Ein- und Austritt des Verdichters und von einem Stroemungsfeld hinter dem Rotor und Stator der dritten Stufe werden geschildert. Die zum Abschluss des Themas erreichte Betriebszeit von 540 Stunden weist auf einen stoerungsfreien Betrieb der Versuchsanlage hin. (orig./AKF)

  18. 淮阴三站变频变速优化运行的分解-动态规划聚合法%Optimization on variable speed operation with VFD for No.3 Huaiyin pumping station based on decomposition-dynamic programming aggregation method

    Institute of Scientific and Technical Information of China (English)

    龚懿; 程吉林; 张仁田; 张礼华

    2011-01-01

    以泵站多机组变频变速运行日耗电费用最小为目标,构造泵站多机组变频变速日优化运行数学模型.考虑变频装置效率随机组转速变化情况,采用大系统分解-动态规划聚合方法求解.先以泵站日提水耗电费用最小为目标,机组提水量为协调变量,将该模型分解为若干个单机组变频变速日优化运行子模型;再以各机组提水量为决策变量,泵站提水量的离散值为状态变量,构造聚合模型,二者均采用动态规划方法求解.该方法对求解不同型号泵机组或各机组同型号但性能存在差异的泵站变频变速最优化运行问题同样适用.以南水北调东线第三梯级泵站淮阴三站运行为例,获得了一系列优化成果.%The mathematical model of optimal daily operation with variable speed for multiple pump units in single pumping station was constructed by taking the minimal daily electric cost as objective function. Considering the efficiency of variable frequency drive (VFD) varied with the unit rotational speed, the decomposition-dynamic programming aggregation method was applied to solve the model above. Taking minimal daily electric cost as objective function, the water quantity pumped by units as coordinated variable, this model was decomposed into several sub-models of daily optimal operation with variable speed for single pump unit. The constructed aggregation model took water quantity pumped by each pump unit as decision variable, the discrete values of water quantity pumped by pumping station as state variable. Both sub-model and aggregation model were solved by means of dynamic programming method. The decomposition-dynamic programming aggregation method could solve the optimal variable speed operation issues for multiple pump units with different types or the units of the same type with performance differences in single pumping station. Through the study on the operation of No.3 Huaiyin Pumping Station which is the third

  19. 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.

  20. Miniature, Variable-Speed Control Moment Gyroscope

    Science.gov (United States)

    Bilski, Steve; Kline-Schoder, Robert; Sorensen, Paul

    2011-01-01

    The Miniature Variable-Speed Control Moment Gyroscope (MVS-CMG) was designed for small satellites (mass from less than 1 kg up to 500 kg). Currently available CMGs are too large and heavy, and available miniature CMGs do not provide sufficient control authority for use on practical satellites. This primarily results from the need to greatly increase the speed of rotation of the flywheel in order to reduce the flywheel size and mass. This goal was achieved by making use of a proprietary, space-qualified, high-speed (100,000 rpm) motor technology to spin the flywheel at a speed ten times faster than other known miniature CMGs under development. NASA is supporting innovations in propulsion, power, and guidance and navigation systems for low-cost small spacecraft. One of the key enabling technologies is attitude control mechanisms. CMGs are particularly attractive for spacecraft attitude control since they can achieve higher torques with lower mass and power than reaction wheels, and they provide continuous torque capability that enables precision pointing (in contrast to on-off thruster control). The aim of this work was to develop a miniature, variable-speed CMG that is sized for use on small satellites. To achieve improved agility, these spacecraft must be able to slew at high rate, which requires attitude control actuators that can apply torques on the order of 5 N-m. The MVS-CMG is specifically designed to achieve a high-torque output with a minimum flywheel and system mass. The flywheel can be run over a wide range of speeds, which is important to help reduce/eliminate potential gimbal lock, and can be used to optimize the operational envelope of the CMG.

  1. In situ local shock speed and transit shock speed

    Directory of Open Access Journals (Sweden)

    S. Watari

    Full Text Available A useful index for estimating the transit speeds was derived by analyzing interplanetary shock observations. This index is the ratio of the in situ local shock speed and the transit speed; it is 0.6–0.9 for most observed shocks. The local shock speed and the transit speed calculated for the results of the magnetohydrodynamic simulation show good agreement with the observations. The relation expressed by the index is well explained by a simplified propagation model assuming a blast wave. For several shocks the ratio is approximately 1.2, implying that these shocks accelerated during propagation in slow-speed solar wind. This ratio is similar to that for the background solar wind acceleration.

    Keywords. Interplanetary physics (Flare and stream dynamics; Interplanetary shocks; Solar wind plasma

  2. Speed-calming measures and their Effect on driving speed

    DEFF Research Database (Denmark)

    Agerholm, Niels; Knudsen, Daniel; Variyeswaran, Kajan

    2017-01-01

    Speeding increases the risk and severity of accidents, especially for vulnerable road users. Hence, minimisation of speeding in built-up areas is vital. Some countries widely use speed-calming measures (SCs). Documentation shows that SCs reduce speeding considerably although various types...... and designs of SCs affect this reduction. This paper includes studies of the effects from establishment of sinus speed humps of height 10 cm and length 950 cm and chicanes (with a free carriageway width of 5,30 cm and a length between the 0.5 m wide obstacles of 18 m) as a before/after study where the speed...... pattern after establishing SCs is compared with the one before. Floating Car Data used for analyses includes 3,216 trips passing one/more SCs. The main results are that the effect from SCs decreases with the distance from the SCs and that a clear pattern is hard to establish above 75 m from the SC...

  3. Speed control at low wind speeds for a variable speed fixed pitch wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rosmin, N.; Watson, S.J.; Tompson, M. [Loughborough Univ., Loughborough, Leicestershire (United Kingdom)

    2010-03-09

    The maximum power regulation below rated wind speed is regulated by changing the rotor/generator speed at large frequency range in a fixed pitch, variable speed, stall-regulated wind turbine. In order to capture the power at a maximum value the power coefficient is kept at maximum peak point by maintaining the tip speed ratio at its optimum value. The wind industry is moving from stall regulated fixed speed wind turbines to newer improved innovative versions with better reliability. While a stall regulated fixed pitch wind turbine is among the most cost-effective wind turbine on the market, its problems include noise, severe vibrations, high thrust loads and low power efficiency. Therefore, in order to improve such drawbacks, the rotation of the generator speed is made flexible where the rotation can be controlled in variable speed. This paper discussed the development of a simulation model which represented the behaviour of a stall regulated variable speed wind turbine at low wind speed control region by using the closed loop scalar control with adjustable speed drive. The paper provided a description of each sub-model in the wind turbine system and described the scalar control of the induction machine. It was concluded that by using a constant voltage/frequency ratio of the generator's stator side control, the generator speed could be regulated and the generator torque could be controlled to ensure the power coefficient could be maintained close to its maximum value. 38 refs., 1 tab., 10 figs.

  4. The Role of Visual Processing Speed in Reading Speed Development

    OpenAIRE

    Muriel Lobier; Matthieu Dubois; Sylviane Valdois

    2013-01-01

    A steady increase in reading speed is the hallmark of normal reading acquisition. However, little is known of the influence of visual attention capacity on children's reading speed. The number of distinct visual elements that can be simultaneously processed at a glance (dubbed the visual attention span), predicts single-word reading speed in both normal reading and dyslexic children. However, the exact processes that account for the relationship between the visual attention span and reading s...

  5. Speed limits for quantum gates in multiqubit systems

    NARCIS (Netherlands)

    Ashhab, S.; De Groot, P.C.; Nori, F.

    2012-01-01

    We use analytical and numerical calculations to obtain speed limits for various unitary quantum operations in multiqubit systems under typical experimental conditions. The operations that we consider include single-, two-, and three-qubit gates, as well as quantum-state transfer in a chain of qubits

  6. OVER SPEED VIOLATION MANAGEMENT OF A VEHICLE THROUGH ZIGBEE

    Directory of Open Access Journals (Sweden)

    Uma Makeswari.A

    2013-02-01

    Full Text Available In the present day scenario traffic rules are frequently violated by the drivers and over speeding occur due to bad driving behavior. So, a driver assistance system is provided to prevent over speeding,violation of road rules and also to display alert messages. The proposed system has an alerting, recording and reporting system for over speed violation management. The Zigbee transmitter sends the speed limit of the particular lane entered by the vehicle and also gives alerts like “road works”, “steep slopes”, “school zone” in the form of acoustical messages and also in LCD. The receiver unit placed in the vehicle receives the messages and sends to the microcontroller. When speed of the vehicle nears the speed limit itdisplays the warning and if exceeds the limit, the microcontroller records the violated speed and time. The LCD displays the lane speed limit and shows the number of times, speed was violated. A GSMmodule sends message to the nearest traffic personnel immediately after a violation occurs. An authenticated device is also provided, which can be operated only by the traffic police in which he canretrieve the data stored at any time. Increase in the count of violation increases the penalty amount which can be collected in toll gates located nearby.

  7. Peer influence predicts speeding prevalence among teenage drivers.

    Science.gov (United States)

    Simons-Morton, Bruce G; Ouimet, Marie Claude; Chen, Rusan; Klauer, Sheila G; Lee, Suzanne E; Wang, Jing; Dingus, Thomas A

    2012-12-01

    Preventing speed-related crashes could reduce costs and improve efficiency in the transportation industry. This research examined the psychosocial and personality predictors of observed speeding among young drivers. Survey and driving data were collected from 42 newly-licensed teenage drivers during the first 18months of licensure. Speeding (i.e., driving 10mph over the speed limit; about 16km/h) was assessed by comparing speed data collected with recording systems installed in participants' vehicles with posted speed limits. Speeding was correlated with elevated g-force event rates (r=0.335, pb0.05), increased over time, and predicted by day vs. night trips, higher sensation seeking, substance use, tolerance of deviance, susceptibility to peer pressure, and number of risky friends. Perceived risk was a significant mediator of the association between speeding and risky friends. The findings support the contention that social norms may influence teenage speeding behavior and this relationship may operate through perceived risk. Copyright © 2012 National Safety Council and Elsevier Ltd. All rights reserved.

  8. Running springs: speed and animal size.

    Science.gov (United States)

    Farley, C T; Glasheen, J; McMahon, T A

    1993-12-01

    Trotting and hopping animals use muscles, tendons and ligaments to store and return elastic energy as they bounce along the ground. We examine how the musculoskeletal spring system operates at different speeds and in animals of different sizes. We model trotting and hopping as a simple spring-mass system which consists of a leg spring and a mass. We find that the stiffness of the leg spring (k(leg)) is nearly independent of speed in dogs, goats, horses and red kangaroos. As these animals trot or hop faster, the leg spring sweeps a greater angle during the stance phase, and the vertical excursion of the center of mass during the ground contact phase decreases. The combination of these changes to the spring system causes animals to bounce off the ground more quickly at higher speeds. Analysis of a wide size range of animals (0.1-140 kg) at equivalent speeds reveals that larger animals have stiffer leg springs (k(leg) [symbol: see text] M0.67, where M is body mass), but that the angle swept by the leg spring is nearly independent of body mass. As a result, the resonant period of vertical vibration of the spring-mass system is longer in larger animals. The length of time that the feet are in contact with the ground increases with body mass in nearly the same way as the resonant period of vertical vibration.

  9. Power Smoothing of a Variable-Speed Wind Turbine Generator in Association With the Rotor-Speed-Dependent Gain

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeonhee; Kang, Moses; Muljadi, Eduard; Park, Jung-Wook; Kang, Yong Cheol

    2017-07-01

    This paper proposes a power-smoothing scheme for a variable-speed wind turbine generator (WTG) that can smooth out the WTG's fluctuating power caused by varying wind speeds, and thereby keep the system frequency within a narrow range. The proposed scheme employs an additional loop based on the system frequency deviation that operates in conjunction with the maximum power point tracking (MPPT) control loop. Unlike the conventional, fixed-gain scheme, its control gain is modified with the rotor speed. In the proposed scheme, the control gain is determined by considering the ratio of the output of the additional loop to that of the MPPT loop. To improve the contribution of the scheme toward maintaining the frequency while ensuring the stable operation of WTGs, in the low rotor speed region, the ratio is set to be proportional to the rotor speed; in the high rotor speed region, the ratio remains constant. The performance of the proposed scheme is investigated under varying wind conditions for the IEEE 14-bus system. The simulation results demonstrate that the scheme successfully operates regardless of the output power fluctuation of a WTG by adjusting the gain with the rotor speed, and thereby improves the frequency-regulating capability of a WTG.

  10. 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.

  11. 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.

  12. 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.

  13. Pay as You Speed, ISA with incentive for not speeding: results and interpretation of speed data.

    Science.gov (United States)

    Lahrmann, Harry; Agerholm, Niels; Tradisauskas, Nerius; Berthelsen, Kasper K; Harms, Lisbeth

    2012-09-01

    To simulate a market introduction of Intelligent Speed Adaptation (ISA) and to study the effect of a Pay as You Speed (PAYS) concept, a field trial with 153 drivers was conducted during 2007-2009. The participants drove under PAYS conditions for a shorter or a longer period. The PAYS concept consisted of informative ISA linked with economic incentive for not speeding, measured through automatic count of penalty points whenever the speed limit was exceeded. The full incentive was set to 30% of a participant's insurance premium. The participants were exposed to different treatments, with and without incentive crossed with informative ISA present or absent. The results showed that ISA is an efficient tool for reducing speeding particularly on rural roads. The analysis of speed data demonstrated that the proportion of distance driven above the speed where the ISA equipment responded (PDA) was a sensitive measure for reflecting the effect of ISA, whereas mean free flow speed and the 85th percentile speed, were less sensitive to ISA effects. The PDA increased a little over time but still remained at a low level; however, when ISA was turned off, the participants' speeding relapsed to the baseline level. Both informative ISA and incentive ISA reduced the PDA, but there was no statistically significant interaction. Informative reduced it more than the incentive.

  14. A Very Low-Speed Sensorless Induction Motor Drive with Online Stator Resistance identification scheme

    Directory of Open Access Journals (Sweden)

    M. Zaky

    2008-03-01

    Full Text Available Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of greatest importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is firstly verified by simulation. Experimental results are included as well to demonstrate the good performance of the proposed observer and estimation algorithms at low speed.

  15. Wind speed perception and risk.

    Directory of Open Access Journals (Sweden)

    Duzgun Agdas

    Full Text Available BACKGROUND: How accurately do people perceive extreme wind speeds and how does that perception affect the perceived risk? Prior research on human-wind interaction has focused on comfort levels in urban settings or knock-down thresholds. No systematic experimental research has attempted to assess people's ability to estimate extreme wind speeds and perceptions of their associated risks. METHOD: We exposed 76 people to 10, 20, 30, 40, 50, and 60 mph (4.5, 8.9, 13.4, 17.9, 22.3, and 26.8 m/s winds in randomized orders and asked them to estimate wind speed and the corresponding risk they felt. RESULTS: Multilevel modeling showed that people were accurate at lower wind speeds but overestimated wind speeds at higher levels. Wind speed perceptions mediated the direct relationship between actual wind speeds and perceptions of risk (i.e., the greater the perceived wind speed, the greater the perceived risk. The number of tropical cyclones people had experienced moderated the strength of the actual-perceived wind speed relationship; consequently, mediation was stronger for people who had experienced fewer storms. CONCLUSION: These findings provide a clearer understanding of wind and risk perception, which can aid development of public policy solutions toward communicating the severity and risks associated with natural disasters.

  16. Wind Speed Perception and Risk

    Science.gov (United States)

    Agdas, Duzgun; Webster, Gregory D.; Masters, Forrest J.

    2012-01-01

    Background How accurately do people perceive extreme wind speeds and how does that perception affect the perceived risk? Prior research on human–wind interaction has focused on comfort levels in urban settings or knock-down thresholds. No systematic experimental research has attempted to assess people's ability to estimate extreme wind speeds and perceptions of their associated risks. Method We exposed 76 people to 10, 20, 30, 40, 50, and 60 mph (4.5, 8.9, 13.4, 17.9, 22.3, and 26.8 m/s) winds in randomized orders and asked them to estimate wind speed and the corresponding risk they felt. Results Multilevel modeling showed that people were accurate at lower wind speeds but overestimated wind speeds at higher levels. Wind speed perceptions mediated the direct relationship between actual wind speeds and perceptions of risk (i.e., the greater the perceived wind speed, the greater the perceived risk). The number of tropical cyclones people had experienced moderated the strength of the actual–perceived wind speed relationship; consequently, mediation was stronger for people who had experienced fewer storms. Conclusion These findings provide a clearer understanding of wind and risk perception, which can aid development of public policy solutions toward communicating the severity and risks associated with natural disasters. PMID:23226230

  17. Pay as You Speed, ISA with incentive for not speeding

    DEFF Research Database (Denmark)

    Lahrmann, Harry; Agerholm, Niels; Tradisauskas, Nerius

    2012-01-01

    To simulate a market introduction of Intelligent Speed Adaptation (ISA) and to study the effect of a Pay as You Speed (PAYS) concept, a field trial with 153 drivers was conducted during 2007–2009. The participants drove under PAYS conditions for a shorter or a longer period. The PAYS concept cons...

  18. Smooth torque speed characteristic of switched reluctance motors

    DEFF Research Database (Denmark)

    Zeng, Hui; Chen, Zhe; Chen, Hao

    2014-01-01

    of the constraints of the supply voltage and peak current. Based on previous work that sought to expand the STO range, a scheme is developed in this study to determine the maximum smooth torque range at each speed. The relationship between the maximum smooth torque and speed is defined as the smooth torque speed......The torque ripple of switched reluctance motors (SRMs) is the main disadvantage that limits the industrial application of these motors. Although several methods for smooth-toque operation (STO) have been proposed, STO works well only within a certain torque and speed range because...... characteristics (STSC), a concept similar to torque speed characteristics (TSC). STSC can be utilized to evaluate torque utilization by comparing it with TSC. Thus, the concept benefits the special design of SRMs, especially for the generation of smooth torque. Furthermore, the torque sharing function (TSF...

  19. Reduction Vehicle Speed Using GPS Android Smart Phone Programming

    Directory of Open Access Journals (Sweden)

    Sameer Sami Hassan

    2017-07-01

    Full Text Available Today the new generation of smart phone such as Samsung galaxy, Sony, Motorola, HTC is used to build smart applications that made the human life more comfortable and safe. The Android open source operating system with java programming language can be used to develop such applications. In this paper a new software application has been developed using Samsung, galaxy note smart phone to control the speed of vehicle using GPS and Android programming for such smart phone. By collecting the speed and location information from Global Position System (GPS receiver and using the global map application programming interface to determine the location nearby university, school and hospital in Baghdad city. The application will be check the speed of vehicle in zone of school, hospital and university using GPS information. If the speed over the limit the application produce sound alarm to reduce the speed to set up limit.

  20. High Speed Exit Taxiways.

    Science.gov (United States)

    1981-02-01

    E -4 ’ i ~.1 ’i -i C; aa fillli -4i E E c ACKNOWLEDGEMENT This report is an edited version of the work undertaken by Max H. Coggins , Ronald B...type. (Ref. d) 2.1.4 The NASA Langley Terminal Configured Vehicle (TCV) program c:nduct,2 aircraft operational tests , collected data, and performed...analysis to demonstrate the feasibility of markedly increasing the air carrier aircraft arrival acceptance tate of suitably designed airport runways. Tests

  1. 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

  2. Is there a speed limit for trapped ion quantum computers?

    CERN Document Server

    Lau, Hoi-Kwan

    2011-01-01

    We investigate a speed limit for quantum processing for trapped ion quantum computers using the Kielpinski-Monroe-Wineland (KMW) architecture. The limiting speed for single-ion shuttling between a storage trap and a logic trap is constrained by the need to avoid excessive ion heating, excessive dephasing and decoherence due to the D.C. Stark effect. We estimate the relative significance of these errors and find that dephasing is dominant. We find that the minimum magnitude of dephasing is quadratic in the time of flight, and an inverse cubic in the operational time scale; from these relations, a limit on the operational speed of ion-trap quantum computers is deduced. Without subsequent phase correction, the maximum speed a qubit can be transferred across a 100 micron-long trap, without excessive error, in about 10 ns for calcium ion and 50 ps for beryllium ion.

  3. Operation Design of Wind Turbines in Strong Wind Conditions

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Montes, Melissa Barroso; Odgaard, Peter Fogh

    2012-01-01

    In order to reduce the impact on the electrical grid from the shutdown of MW wind turbines at wind speeds higher than the cut-out wind speed of 25 m/s, we propose in this paper to run the turbines at high wind speeds up to 40 m/s. Two different operation designs are made for both constant speed...

  4. 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.

  5. 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.

  6. Control of Variable Speed Variable Pitch Wind Turbine at Above and Below Rated Wind Speed

    Directory of Open Access Journals (Sweden)

    Saravanakumar Rajendran

    2014-01-01

    Full Text Available The paper presents a nonlinear approach to wind turbine (WT using two-mass model. The main aim of the controller in the WT is to maximize the energy output at varying wind speed. In this work, a combination of linear and nonlinear controllers is adapted to variable speed variable pitch wind turbines (VSVPWT system. The major operating regions of the WT are below (region 2 and above rated (region 3 wind speed. In these regions, generator torque control (region 2 and pitch control (region 3 are used. The controllers in WT are tested for below and above rated wind speed for step and vertical wind speed profile. The performances of the controllers are analyzed with nonlinear FAST (Fatigue, Aerodynamics, Structures, and Turbulence WT dynamic simulation. In this paper, two nonlinear controllers, that is, sliding mode control (SMC and integral sliding mode control (ISMC, have been applied for region 2, whereas for pitch control in region 3 conventional PI control is used. In ISMC, the sliding manifold makes use of an integral action to show effective qualities of control in terms of the control level reduction and sliding mode switching control minimization.

  7. Overview of Variable-Speed Power-Turbine Research

    Science.gov (United States)

    Welch, Gerard E.

    2011-01-01

    The vertical take-off and landing (VTOL) and high-speed cruise capability of the NASA Large Civil Tilt-Rotor (LCTR) notional vehicle is envisaged to enable increased throughput in the national airspace. A key challenge of the LCTR is the requirement to vary the main rotor speeds from 100% at take-off to near 50% at cruise as required to minimize mission fuel burn. The variable-speed power-turbine (VSPT), driving a fixed gear-ratio transmission, provides one approach for effecting this wide speed variation. The key aerodynamic and rotordynamic challenges of the VSPT were described in the FAP Conference presentation. The challenges include maintaining high turbine efficiency at high work factor, wide (60 deg.) of incidence variation in all blade rows due to the speed variation, and operation at low Reynolds numbers (with transitional flow). The PT -shaft of the VSPT must be designed for safe operation in the wide speed range required, and therefore poses challenges associated with rotordynamics. The technical challenges drive research activities underway at NASA. An overview of the NASA SRW VSPT research activities was provided. These activities included conceptual and preliminary aero and mechanical (rotordynamics) design of the VSPT for the LCTR application, experimental and computational research supporting the development of incidence tolerant blading, and steps toward component-level testing of a variable-speed power-turbine of relevance to the LCTR application.

  8. Capacity factors of a mixed speed railway network

    DEFF Research Database (Denmark)

    Harrod, Steven

    2009-01-01

    Fifty-four combinations of track network and speed differential are evaluated within a linear, discrete time network model that maximizes an objective function of train volume, delays, and idle train time. The results contradict accepted dispatching practice by suggesting that when introducing...... a priority, high-speed train onto a network, maximum network now is attained when the priority train operates at maximum speed. in addition, increasing siding capacity at meeting points may offer a network capacity improvement comparable to partial double track. (C) 2009 Elsevier Ltd. All rights reserved....

  9. Time-limited optimal dynamics beyond the Quantum Speed Limit

    DEFF Research Database (Denmark)

    Gajdacz, Miroslav; Das, Kunal K.; Arlt, Jan

    2015-01-01

    -off expressed in terms of the direct Hilbert velocity provides a robust prediction of the quantum speed limit and allows to adapt the control optimization such that it yields a predefined fidelity. The results are verified numerically in a multilevel system with a constrained Hamiltonian, and a classification......The quantum speed limit sets the minimum time required to transfer a quantum system completely into a given target state. At shorter times the higher operation speed has to be paid with a loss of fidelity. Here we quantify the trade-off between the fidelity and the duration in a system driven...

  10. NTF – wind speed comparison

    DEFF Research Database (Denmark)

    Vesth, Allan; Gómez Arranz, Paula

    The report describes measurements carried out on a given turbine. A comparison between wind speed on the met mast and Nacelle Wind speed are made and the results are presented on graphs and in a table. The data used for the comparison are the data that are same as used for the power curve report...

  11. Optimal Speed Control for Cruising

    DEFF Research Database (Denmark)

    Blanke, M.

    1994-01-01

    With small profit margins in merchant shipping and more than eighty percent of sailing time being cross ocean voyages, speed control is crucial for vessel profitability......With small profit margins in merchant shipping and more than eighty percent of sailing time being cross ocean voyages, speed control is crucial for vessel profitability...

  12. How to Improve Reading Speed

    Institute of Scientific and Technical Information of China (English)

    王仲亮

    2008-01-01

    @@ It is well known that reading plays an important role not only in our daily life but also in learning a foreign language.And,of course,reading depends on reading speed to some degree.So it is natural that it is important to improve reading speed.

  13. Optimal Speed Control for Cruising

    DEFF Research Database (Denmark)

    Blanke, M.

    1994-01-01

    With small profit margins in merchant shipping and more than eighty percent of sailing time being cross ocean voyages, speed control is crucial for vessel profitability......With small profit margins in merchant shipping and more than eighty percent of sailing time being cross ocean voyages, speed control is crucial for vessel profitability...

  14. Comparison of Wind Power Converter Reliability with Low-Speed and Medium-Speed Permanent-Magnet Synchronous Generators

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Franke, Toke

    2015-01-01

    of the low-speed (direct-drive) and medium-speed (one-stage) permanent-magnet synchronous generators are both promising solutions. This paper will assess and compare the reliability metrics for the machine-side converter for those two configurations. First, a translation from the mission profile......, according to the lifetime power cycles, the lifespan can be calculated when operating in various wind classes. It is concluded that, although the low-speed permanent-magnet synchronous generator is able to eliminate the gearbox, the lifespan of its machine-side converter is lower than the one-stage medium...

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

    Science.gov (United States)

    2015-04-27

    SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6. AUTHORS 7. PERFORMING ORGANIZATION NAMES AND ADDRESSES 15. SUBJECT TERMS ...growth using metalorganic chemical vapor deposition (MOCVD). These methods allowed us to realize quantum dot active regions in which the injected carriers...temperature sensitivity , commonly observed in self-assembled QD lasers2. An alternate approach to SK QD formation is the use of nanopatterning with

  16. Diesel engine torsional vibration control coupling with speed control system

    Science.gov (United States)

    Guo, Yibin; Li, Wanyou; Yu, Shuwen; Han, Xiao; Yuan, Yunbo; Wang, Zhipeng; Ma, Xiuzhen

    2017-09-01

    The coupling problems between shafting torsional vibration and speed control system of diesel engine are very common. Neglecting the coupling problems sometimes lead to serious oscillation and vibration during the operation of engines. For example, during the propulsion shafting operation of a diesel engine, the oscillation of engine speed and the severe vibration of gear box occur which cause the engine is unable to operate. To find the cause of the malfunctions, a simulation model coupling the speed control system with the torsional vibration of deformable shafting is proposed and investigated. In the coupling model, the shafting is simplified to be a deformable one which consists of several inertias and shaft sections and with characteristics of torsional vibration. The results of instantaneous rotation speed from this proposed model agree with the test results very well and are successful in reflecting the real oscillation state of the engine operation. Furthermore, using the proposed model, the speed control parameters can be tuned up to predict the diesel engine a stable and safe running. The results from the tests on the diesel engine with a set of tuned control parameters are consistent with the simulation results very well.

  17. 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.

  18. 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.

  19. The Optimum Speed Limit. Revised.

    Science.gov (United States)

    1983-07-01

    Relating U, and U to the values of life and time eases the interpretation: (2) U, -vX; (2a) U, -V. XI where: V, is the dollar value of time (more precisely...by (3) I V [ as ;as Equation (3) shows that for an individual, the optimal speed depends positively on his value of time and negatively on his...fatality rates to driving speed and gas mileage to speed. The value of time and the value of a life are harder to determine because they cannot be

  20. 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....

  1. 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.

  2. Dynamic Dazzle Distorts Speed Perception.

    Directory of Open Access Journals (Sweden)

    Joanna R Hall

    Full Text Available Static high contrast ('dazzle' patterns, such as zigzags, have been shown to reduce the perceived speed of an object. It has not escaped our notice that this effect has possible military applications and here we report a series of experiments on humans, designed to establish whether dynamic dazzle patterns can cause distortions of perceived speed sufficient to provide effective defence in the field, and the extent to which these effects are robust to a battery of manipulations. Dynamic stripe patterns moving in the same direction as the target are found to increase the perceived speed of that target, whilst dynamic stripes moving in the opposite direction to the target reduce the perceived speed. We establish the optimum position for such dazzle patches; confirm that reduced contrast and the addition of colour do not affect the performance of the dynamic dazzle, and finally, using the CO2 challenge, show that the effect is robust to stressful conditions.

  3. Predictors of Social Mobilization Speed

    CERN Document Server

    Alstott, Jeff; Velu, Chander

    2013-01-01

    Mobilization across social networks is becoming increasingly influential, but little is known about what traits of individuals and their relationships affect their speed of mobilization between them. We ran a global social mobilization contest and recorded personal traits of the participants and those they mobilized. We examined how those traits influenced the speed of mobilization. Individuals mobilized faster when they heard about the contest directly from the contest organization, and decreased in speed when hearing from less personal source types (e.g. family vs. media). Mobilization was faster when the mobilizer and the mobilized heard about the contest through the same source type, and slower when both individuals were in different countries. Females mobilized other females faster than males mobilized other males. Mobilization was faster with young recruiters and old recruits, and slower with old recruiters and young recruits. These findings suggest ways to optimize the speed of social mobilization.

  4. An Alternative Approach for High Speed Railway Carrying Capacity Calculation Based on Multiagent Simulation

    Directory of Open Access Journals (Sweden)

    Mo Gao

    2016-01-01

    Full Text Available It is a multiobjective mixed integer programming problem that calculates the carrying capacity of high speed railway based on mathematical programming method. The model is complex and difficult to solve, and it is difficult to comprehensively consider the various influencing factors on the train operation. The multiagent theory is employed to calculate high speed railway carrying capacity. In accordance with real operations of high speed railway, a three-layer agent model is developed to simulate the operating process of high speed railway. In the proposed model, railway network agent, line agent, station agent, and train agent are designed, respectively. To validate the proposed model, a case study is performed for Beijing–Shanghai high speed railway by using NetLogo software. The results are consistent with the actual data, which implies that the proposed multiagent method is feasible to calculate the carrying capacity of high speed railway.

  5. 高速铁路隧道工程水沟电缆槽一次成型施工技术%Technology for Concreting of Integrated Drainage Ditch and Cable Channel of High-speed Railway Tunnels in One Operation

    Institute of Scientific and Technical Information of China (English)

    尹忠辉

    2014-01-01

    高速铁路隧道工程水沟电缆槽一般分为通信信号槽、电力电缆槽、排水槽,三槽合一,根据高速铁路的设计理念与运营要求,水沟电缆槽必须一次成型,在施工中为了设计出一套系统的电缆槽一次成型配套模板体系,在实践的基础上利用组合模板桁架连接与走行系统结合的方式对电缆槽一次成型施工进行探索和总结。实践证明:合理地利用桁架模板与走行系统设计出的电缆槽模板,可以有效地完成高速铁路隧道工程水沟电缆槽的一次成型要求。%The drainage ditches and cable channels of tunnels on high-speed railways include communication cable channels,electrical power cable channels and drainage ditches.These three types of channels/ditches are integrated into one body and must be concreted in one operation.In the paper,a set of formworks for the concreting of the drainage ditch and cable channel is designed and the concreting of the drainage ditch and cable channel is described.The con-struction practice demonstrates that the formwork system with truss structure and moving system can meet the require-ments of the concreting of the integrated drainage ditch and cable channel in one operation.

  6. Do Speed Cameras Reduce Collisions?

    OpenAIRE

    Skubic, Jeffrey; Johnson, Steven B.; Salvino, Chris; Vanhoy, Steven; Hu, Chengcheng

    2013-01-01

    We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods – before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not indepe...

  7. Do speed cameras reduce collisions?

    Science.gov (United States)

    Skubic, Jeffrey; Johnson, Steven B; Salvino, Chris; Vanhoy, Steven; Hu, Chengcheng

    2013-01-01

    We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods - before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not independently affect the incidence of motor vehicle collisions.

  8. Code Speed Measuring for VC++

    Science.gov (United States)

    2015-10-01

    UNCLASSIFIED AD-E403 688 Technical Report ARWSE-TR-14025 CODE SPEED MEASURING FOR VC++ Tom Nealis...TYPE Final 3. DATES COVERED (From – To) 4. TITLE AND SUBTITLE CODE SPEED MEASURING FOR VC++ 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...ABSTRACT It’s often important to know how fast a snippet of code executes. This information allows the coder to make important decisions

  9. Speed Variance and Its Influence on Accidents.

    Science.gov (United States)

    Garber, Nicholas J.; Gadirau, Ravi

    A study was conducted to investigate the traffic engineering factors that influence speed variance and to determine to what extent speed variance affects accident rates. Detailed analyses were carried out to relate speed variance with posted speed limit, design speeds, and other traffic variables. The major factor identified was the difference…

  10. 36 CFR 4.21 - Speed limits.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Speed limits. 4.21 Section 4... TRAFFIC SAFETY § 4.21 Speed limits. (a) Park area speed limits are as follows: (1) 15 miles per hour... superintendent may designate a different speed limit upon any park road when a speed limit set forth in...

  11. Speed management : enforcement and new technologies.

    NARCIS (Netherlands)

    Wegman, F.C.M. & Goldenbeld, C.

    2006-01-01

    Due to the massive character of speeding and inappropriate travel speeds, speed management continues to be an important and challenging policy area. Estimates are that in about a quarter to one third of fatal crashes excessive speeds are involved, making speed one of the crucial factors in road safe

  12. Rapid Speed Modulation of a Rotary Total Artificial Heart Impeller.

    Science.gov (United States)

    Kleinheyer, Matthias; Timms, Daniel L; Tansley, Geoffrey D; Nestler, Frank; Greatrex, Nicholas A; Frazier, O Howard; Cohn, William E

    2016-09-01

    Unlike the earlier reciprocating volume displacement-type pumps, rotary blood pumps (RBPs) typically operate at a constant rotational speed and produce continuous outflow. When RBP technology is used in constructing a total artificial heart (TAH), the pressure waveform that the TAH produces is flat, without the rise and fall associated with a normal arterial pulse. Several studies have suggested that pulseless circulation may impair microcirculatory perfusion and the autoregulatory response and may contribute to adverse events such as gastrointestinal bleeding, arteriovenous malformations, and pump thrombosis. It may therefore be beneficial to attempt to reproduce pulsatile output, similar to that generated by the native heart, by rapidly modulating the speed of an RBP impeller. The choice of an appropriate speed profile and control strategy to generate physiologic waveforms while minimizing power consumption and blood trauma becomes a challenge. In this study, pump operation modes with six different speed profiles using the BiVACOR TAH were evaluated in vitro. These modes were compared with respect to: hemodynamic pulsatility, which was quantified as surplus hemodynamic energy (SHE); maximum rate of change of pressure (dP/dt); pulse power index; and motor power consumption as a function of pulse pressure. The results showed that the evaluated variables underwent different trends in response to changes in the speed profile shape. The findings indicated a possible trade-off between SHE levels and flow rate pulsatility related to the relative systolic duration in the speed profile. Furthermore, none of the evaluated measures was sufficient to fully characterize hemodynamic pulsatility.

  13. 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.

  14. Cognitive Processing Speed across the Lifespan: Beyond the Influence of Motor Speed

    Science.gov (United States)

    Ebaid, Deena; Crewther, Sheila G.; MacCalman, Kirsty; Brown, Alyse; Crewther, Daniel P.

    2017-01-01

    Traditional neuropsychological measurement of cognitive processing speed with tasks such as the Symbol Search and Coding subsets of the WAIS-IV, consistently show decline with advancing age. This is potentially problematic with populations where deficits in motor performance are expected, i.e., in aging or stroke populations. Thus, the aim of the current study was to explore the contribution of hand motor speed to traditional paper-and-pencil measures of processing speed and to a simple computer-customized non-motor perception decision task, the Inspection Time (IT) task. Participants were 67 young university students aged between 18 and 29 (59 females), and 40 older adults aged between 40 and 81 (31 females) primarily with a similar education profile. As expected, results indicated that age group differences were highly significant on the motor dexterity, Symbol Search and Coding tasks. However, no significant differences or correlations were seen between age groups and the simple visual perception IT task. Furthermore, controlling for motor dexterity did not remove significant age-group differences on the paper-and-pencil measures. This demonstrates that although much of past research into cognitive decline with age is confounded by use of motor reaction times as the operational measure, significant age differences in cognitive processing also exist on more complex tasks. The implications of the results are crucial in the realm of aging research, and caution against the use of traditional WAIS tasks with a clinical population where motor speed may be compromised, as in stroke. PMID:28381999

  15. 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.

  16. Transient stability of a fixed speed wind farm

    Energy Technology Data Exchange (ETDEWEB)

    Ledesma, P.; Usaola, J.; Rodriguez, J.L. [Universidad Carlos III de Madrid, Madrid (Spain)

    2003-07-01

    A typical fixed speed wind farm connected to a simple grid is modelled. Using this model, a three-phase fault is applied close to the wind farm, and cleared by disconnecting the affected line. The effect of several electric, mechanical and operational parameters on the critical fault-clearing time of this base case is evaluated and discussed. The studied parameters are the short-circuit power at the connection bus, the reactive power compensation, the distance to the fault, the rotor inertia, the hub-generator resonant frequency, the wind speed and the power output. For each parameter, the relationship between its value and the critical fault-clearing time is shown graphically. The results help to understand the transient stability phenomena in fixed speed wind farms, and could help to design fixed speed wind farms attending to transient stability requirements. (Author)

  17. A speed estimation of sensorless control for asymmetrical parameter type two-phase induction motor drives

    Directory of Open Access Journals (Sweden)

    Nuttapong Muangchan

    2015-06-01

    Full Text Available This paper presents the concept of a speed estimation of sensorless control for asymmetrical parameter type two-phase induction motor drive, by using the adaptive observer system. The motor speed is estimated on the rotor-flux reference frame to simplicity for application. The design guideline of the gain of speed estimate system for a motor has speed change. The experimental results for all test conditions show that the responses of current, torque and speed are stable for the entire operating region.

  18. Adaptive Backstepping design of an Observer for the Rotor Speed and Field of an Induction Motor

    DEFF Research Database (Denmark)

    Rasmussen, Henrik

    2001-01-01

    is de-veloped. The resulting scheme leads to a nonlinear full order observer for the rotor field. The rotor speed and the stator resis-tance are estimated by adaptive backstepping. Assuming motor parameters known the design achieves stability with guaran-teed region of attraction. The adaptive......High performance operation of speed controlled AC drives without mechanical speed/position sensors rely on the dynamic models for estimation of flux and speed. Using backstepping, which is a recursive nonlinear design method, a new approach for the design of observers for speed sensorless control...

  19. 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

  20. 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.

  1. High speed roll casting of Mg alloy strip by a vertical type twin roll caster

    OpenAIRE

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

    2006-01-01

    Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm wi...

  2. Control of a High Speed Flywheel System for Energy Storage in Space Applications

    Science.gov (United States)

    Kenny, Barbara H.; Kascak, Peter E.; Jansen, Ralph; Dever, Timothy; Santiago, Walter

    2004-01-01

    A novel control algorithm for the charge and discharge modes of operation of a flywheel energy storage system for space applications is presented. The motor control portion of the algorithm uses sensorless field oriented control with position and speed estimates determined from a signal injection technique at low speeds and a back EMF technique at higher speeds. The charge and discharge portion of the algorithm use command feed-forward and disturbance decoupling, respectively, to achieve fast response with low gains. Simulation and experimental results are presented demonstrating the successful operation of the flywheel control up to the rated speed of 60,000 rpm.

  3. 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.

  4. Low speed phaselock speed control system. [for brushless dc motor

    Science.gov (United States)

    Fulcher, R. W.; Sudey, J. (Inventor)

    1975-01-01

    A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

  5. Analysis of a teetered, variable-speed rotor: final report

    Energy Technology Data Exchange (ETDEWEB)

    Weber, T L; Wilson, R E; Walker, S N [Oregon State Univ., Corvallis, OR (USA). Dept. of Mechanical Engineering

    1991-06-01

    A computer model of a horizontal axis wind turbine (HOOT) with four structural degrees of freedom has been derived and verified. The four degrees of freedom include flapwise motion of the blades, teeter motion, and variable rotor speed. Options for the variable rotor speed include synchronous, induction, and constant-tip speed generator models with either start, stop, or normal operations. Verification is made by comparison with analytical solutions and mean and cyclic ESI-80 data. The Veers full-field turbulence model is used as a wind input for a synchronous and induction generator test case during normal operation. As a result of the comparison, it is concluded that the computer model can be used to predict accurately mean and cyclic loads with a turbulent wind input. 47 refs., 19 figs.

  6. Generalized Geometric Quantum Speed Limits

    Science.gov (United States)

    Pires, Diego Paiva; Cianciaruso, Marco; Céleri, Lucas C.; Adesso, Gerardo; Soares-Pinto, Diogo O.

    2016-04-01

    The attempt to gain a theoretical understanding of the concept of time in quantum mechanics has triggered significant progress towards the search for faster and more efficient quantum technologies. One of such advances consists in the interpretation of the time-energy uncertainty relations as lower bounds for the minimal evolution time between two distinguishable states of a quantum system, also known as quantum speed limits. We investigate how the nonuniqueness of a bona fide measure of distinguishability defined on the quantum-state space affects the quantum speed limits and can be exploited in order to derive improved bounds. Specifically, we establish an infinite family of quantum speed limits valid for unitary and nonunitary evolutions, based on an elegant information geometric formalism. Our work unifies and generalizes existing results on quantum speed limits and provides instances of novel bounds that are tighter than any established one based on the conventional quantum Fisher information. We illustrate our findings with relevant examples, demonstrating the importance of choosing different information metrics for open system dynamics, as well as clarifying the roles of classical populations versus quantum coherences, in the determination and saturation of the speed limits. Our results can find applications in the optimization and control of quantum technologies such as quantum computation and metrology, and might provide new insights in fundamental investigations of quantum thermodynamics.

  7. Dazzle camouflage affects speed perception.

    Directory of Open Access Journals (Sweden)

    Nicholas E Scott-Samuel

    Full Text Available Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

  8. Generalized Geometric Quantum Speed Limits

    Directory of Open Access Journals (Sweden)

    Diego Paiva Pires

    2016-06-01

    Full Text Available The attempt to gain a theoretical understanding of the concept of time in quantum mechanics has triggered significant progress towards the search for faster and more efficient quantum technologies. One of such advances consists in the interpretation of the time-energy uncertainty relations as lower bounds for the minimal evolution time between two distinguishable states of a quantum system, also known as quantum speed limits. We investigate how the nonuniqueness of a bona fide measure of distinguishability defined on the quantum-state space affects the quantum speed limits and can be exploited in order to derive improved bounds. Specifically, we establish an infinite family of quantum speed limits valid for unitary and nonunitary evolutions, based on an elegant information geometric formalism. Our work unifies and generalizes existing results on quantum speed limits and provides instances of novel bounds that are tighter than any established one based on the conventional quantum Fisher information. We illustrate our findings with relevant examples, demonstrating the importance of choosing different information metrics for open system dynamics, as well as clarifying the roles of classical populations versus quantum coherences, in the determination and saturation of the speed limits. Our results can find applications in the optimization and control of quantum technologies such as quantum computation and metrology, and might provide new insights in fundamental investigations of quantum thermodynamics.

  9. 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

  10. 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.

  11. 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.)

  12. 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.

  13. 32 CFR 634.27 - Speed-measuring devices.

    Science.gov (United States)

    2010-07-01

    ... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Traffic Supervision § 634.27 Speed-measuring.... (v) Demonstrate basic skills in checking calibration and operating the specific radar instrument(s). (vi) Demonstrate basic skills in preparing and presenting records and courtroom testimony relating...

  14. 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.

  15. Motivating Inhibition--Reward Prospect Speeds up Response Cancellation

    Science.gov (United States)

    Boehler, Carsten N.; Hopf, Jens-Max; Stoppel, Christian M.; Krebs, Ruth M.

    2012-01-01

    Reward prospect has been demonstrated to facilitate various cognitive and behavioral operations, particularly by enhancing the speed and vigor of processes linked to approaching reward. Studies in this domain typically employed task regimes in which participants' overt responses are facilitated by prospective rewards. In contrast, we demonstrate…

  16. Disturbance observer that uses radial basis function networks for the low speed control of a servo motor

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Bae, C.H.; Blaabjerg, Frede

    2005-01-01

    A scheme to estimate the moment of inertia in a servo motor drive system at very low speed is proposed. The typical speed estimation scheme used in most servo systems operated at low speed is highly sensitive to variations in the moment of inertia. An observer that uses a radial basis function ne...

  17. Instant PageSpeed optimization

    CERN Document Server

    Jaiswal, Sanjeev

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. Instant PageSpeed Optimization is a hands-on guide that provides a number of clear, step-by-step exercises for optimizing your websites for better performance and improving their efficiency.Instant PageSpeed Optimization is aimed at website developers and administrators who wish to make their websites load faster without any errors and consume less bandwidth. It's assumed that you will have some experience in basic web technologies like HTML, CSS3, JavaScript, and the basics of netw

  18. Speeding chemical reactions by focusing

    CERN Document Server

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  19. 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

  20. The Enhanced Speed Bag System

    Science.gov (United States)

    2016-03-18

    system for helicopter resupply is a crucial development in aerial sustainment .  By Capt. Jude G.B. Coe Three enhanced speed bag systems are rigged on...NI NG & ED UC AT IO N 47 Army Sustainment July–August 2015 multipurpose cargo bag with pad- ding, one speed line assembly with a cable grip that...understand- ing of how to set up and rig the ESBS inside a Black Hawk. Validation Exercise After two joint in-progress reviews , Task Force Talon and the Iron

  1. Speed of Gravity Measured for First Time

    Science.gov (United States)

    2003-01-01

    learn about this intriguing cosmic force and its relationship to the other forces in nature," Kopeikin said. This is not the first time that Jupiter has played a part in producing a measurement of a fundamental physical constant. In 1675, Olaf Roemer, a Danish astronomer working at the Paris Observatory, made the first reasonably accurate determination of the speed of light by observing eclipses of one of Jupiter's moons. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  2. Flicker study on variable speed wind turbines with doubly fed induction generators

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    Grid connected wind turbines may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a doubly fed induction generator developed in the simulation tool of PSCAD/EMTDC. Flicker emission of variable speed wind turbines...... with doubly fed induction generators is investigated during continuous operation, and the dependence of flicker emission on mean wind speed, wind turbulence intensity, short circuit capacity of grid and grid impedance angle are analyzed. A comparison is done with the fixed speed wind turbine, which leads...... to a conclusion that the factors mentioned above have different influences on flicker emission compared with that in the case of the fixed speed wind turbine. Flicker mitigation is realized by output reactive power control of the variable speed wind turbine with doubly fed induction generator. Simulation results...

  3. A Variable-Speed Approach for Preventing Cam-Follower Separation

    Science.gov (United States)

    Yan, Hong-Sen; Tsai, Wu-Jung

    The follower separation is a major impediment to the operating speed increase of force-closed cam mechanisms. This problem traditionally is solved by increasing the spring preload or spring rate to enlarge the return force. An alternative approach with variable cam speed is proposed to prevent follower separation and thereby to raise the average operating speed. By properly designing the cam speed to change the follower motion, the critical motion characteristics leading to follower separation can be avoided. The cam speed trajectory is expressed using the Bezier function. A mathematical model is developed for analyzing the cycle time and the critical times of follower separation. Then a design model for optimizing the critical average cam speed without follower separation is developed to specify the design parameters of this trajectory. Two design examples with different cam motion programs are given for demonstrating the feasibility of this approach.

  4. Time Series Model of Wind Speed for Multi Wind Turbines based on Mixed Copula

    Directory of Open Access Journals (Sweden)

    Nie Dan

    2016-01-01

    Full Text Available Because wind power is intermittent, random and so on, large scale grid will directly affect the safe and stable operation of power grid. In order to make a quantitative study on the characteristics of the wind speed of wind turbine, the wind speed time series model of the multi wind turbine generator is constructed by using the mixed Copula-ARMA function in this paper, and a numerical example is also given. The research results show that the model can effectively predict the wind speed, ensure the efficient operation of the wind turbine, and provide theoretical basis for the stability of wind power grid connected operation.

  5. Perils of using speed zone data to assess real-world compliance to speed limits.

    Science.gov (United States)

    Chevalier, Anna; Clarke, Elizabeth; Chevalier, Aran John; Brown, Julie; Coxon, Kristy; Ivers, Rebecca; Keay, Lisa

    2017-04-05

    Real-world driving studies, including those involving speeding alert devices and autonomous vehicles, can gauge an individual vehicle's speeding behavior by comparing measured speed with mapped speed zone data. However, there are complexities with developing and maintaining a database of mapped speed zones over a large geographic area that may lead to inaccuracies within the data set. When this approach is applied to large-scale real-world driving data or speeding alert device data to determine speeding behavior, these inaccuracies may result in invalid identification of speeding. We investigated speeding events based on service provider speed zone data. We compared service provider speed zone data (Speed Alert by Smart Car Technologies Pty Ltd., Ultimo, NSW, Australia) against a second set of speed zone data (Google Maps Application Programming Interface [API] mapped speed zones). We found a systematic error in the zones where speed limits of 50-60 km/h, typical of local roads, were allocated to high-speed motorways, which produced false speed limits in the speed zone database. The result was detection of false-positive high-range speeding. Through comparison of the service provider speed zone data against a second set of speed zone data, we were able to identify and eliminate data most affected by this systematic error, thereby establishing a data set of speeding events with a high level of sensitivity (a true positive rate of 92% or 6,412/6,960). Mapped speed zones can be a source of error in real-world driving when examining vehicle speed. We explored the types of inaccuracies found within speed zone data and recommend that a second set of speed zone data be utilized when investigating speeding behavior or developing mapped speed zone data to minimize inaccuracy in estimates of speeding.

  6. Hydrogen tube vehicle for supersonic transport: 2. Speed and energy

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Arnold R. [Vehicle Projects Inc and Supersonic Tubevehicle LLC, 200 Violet St, Suite 100, Golden, CO 80401 (United States)

    2010-06-15

    The central concept of a new idea in high-speed transport is that operation of a vehicle in a hydrogen atmosphere, because of the low density of hydrogen, would increase sonic speed by a factor of 3.8 and decrease drag by 15 relative to air. A hydrogen atmosphere requires that the vehicle operate within a hydrogen-filled tube or pipeline, which serves as a phase separator. The supersonic tube vehicle (STV) can be supersonic with respect to air outside the tube while remaining subsonic inside. It breathes hydrogen fuel for its propulsion fuel cells from the tube itself. This paper, second in a series on the scientific foundations of the supersonic tube vehicle, tests the hypothesis that the STV will be simultaneously fast and energy efficient by comparing its predicted speed and energy consumption with that of four long-haul passenger transport modes: road, rail, maglev, and air. The study establishes the speed ranking STV >> airplane > maglev > train > coach (intercity bus) and the normalized energy consumption ranking Airplane >> coach > maglev > train > STV. Consistent with the hypothesis, the concept vehicle is both the fastest and lowest energy consuming mode. In theory, the vehicle can cruise at Mach 2.8 while consuming less than half the energy per passenger of a Boeing 747 at a cruise speed of Mach 0.81. (author)

  7. 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.

  8. 14 CFR 25.1507 - Maneuvering speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  9. Improving homogeneity by dynamic speed limit systems.

    NARCIS (Netherlands)

    Nes, N. van Brandenberg, S. & Twisk, D.A.M.

    2010-01-01

    Homogeneity of driving speeds is an important variable in determining road safety; more homogeneous driving speeds increase road safety. This study investigates the effect of introducing dynamic speed limit systems on homogeneity of driving speeds. A total of 46 subjects twice drove a route along 12

  10. 14 CFR 27.1509 - Rotor speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor speed. 27.1509 Section 27.1509... Rotor speed. (a) Maximum power-off (autorotation). The maximum power-off rotor speed must be established... minimum power-off rotor speed must be established so that it is not less than 105 percent of the...

  11. 14 CFR 29.1509 - Rotor speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor speed. 29.1509 Section 29.1509....1509 Rotor speed. (a) Maximum power-off (autorotation). The maximum power-off rotor speed must be... minimum power-off rotor speed must be established so that it is not less than 105 percent of the...

  12. 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.

  13. 45 CFR 3.26 - Speed limit.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Speed limit. 3.26 Section 3.26 Public Welfare... INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.26 Speed limit. The speed limit is 25 miles per hour, unless otherwise posted. A driver of a vehicle may not exceed the speed limit....

  14. Effective speed management through automatic enforcement.

    NARCIS (Netherlands)

    Oei, H.-l.

    1994-01-01

    This paper analyses several aspects of the Dutch experience of speed enforcement, and presents the results of some speed management experiments in The Netherlands, using automatic warning of speeders and enforcement of speeding. Traditional approaches to manage speed there have not resulted in satis

  15. 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...

  16. Algebra 1's Speed Trap

    Science.gov (United States)

    Gupta, Neil Kenneth

    2004-01-01

    Students often look for real-life situations where they can apply the concepts they learn. A project of measuring the speed of moving cars demonstrates that they learn communication skills, teamwork skills, and develop patience specially when work in a group with a common purpose.

  17. Dual-Resonator Speed Meter for a Free Test Mass

    CERN Document Server

    Braginsky, V B; Khalili, F Ya; Thorne, K S; Braginsky, Vladimir B.; Gorodetsky, Mikhail L.; Khalili, Farid Ya.; Thorne, Kip S.

    2000-01-01

    A description and analysis are given of a ``speed meter'' for monitoring a classical force that acts on a test mass. This speed meter is based on two microwave resonators (``dual resonators''), one of which couples evanescently to the position of the test mass. The sloshing of the resulting signal between the resonators, and a wise choice of where to place the resonators' output waveguide, produce a signal in the waveguide that (for sufficiently low frequencies) is proportional to the test-mass velocity (speed) rather than its position. This permits the speed meter to achieve force-measurement sensitivities better than the standard quantum limit (SQL), both when operating in a narrow-band mode and a wide-band mode. A scrutiny of experimental issues shows that it is feasible, with current technology, to construct a demonstration speed meter that beats the wide-band SQL by a factor 2. A concept is sketched for an adaptation of this speed meter to optical frequencies; this adaptation forms the basis for a possib...

  18. Modeling and Application of PMSG Based Variable Speed Wind Generation System

    OpenAIRE

    S. Sajedi; F. Khalifeh; T. Karimi; Z. Khalifeh

    2012-01-01

    In the early development of wind energy, the majority of wind turbines were operated at constant speed. Recently, the number of variable-speed wind turbines installed in wind farms has increased and more wind turbine manufacturers are making variable-speed wind turbines. In this study maximum power control of wind turbine and permanent magnet synchronous generator connected with two back to back voltage source converters to grid are studied. Machine currents are controlled by indirect vector ...

  19. Hazard Avoidance for High-Speed Mobile Robots in Rough Terrain

    Science.gov (United States)

    2006-05-01

    Accepted to the Journal of Field Robotics 1 Hazard Avoidance for High-Speed Mobile Robots in Rough Terrain Matthew Spenko, Yoji Kuroda, Steven...COVERED 00-00-2006 to 00-00-2006 4. TITLE AND SUBTITLE Hazard Avoidance for High-Speed Mobile Robots in Rough Terrain 5a. CONTRACT NUMBER 5b...Fundamentals of vehicle dynamics. Warrendale, PA: Society of Automotive Engineers. Golda, D. (2003). Modeling and analysis of high-speed mobile robots operating

  20. Generation of Random Wind Speed Profiles for Evaluation of Stress in WT Power Converters

    OpenAIRE

    Pigazo, Alberto; Qin, Zian; Liserre, Marco; Blaabjerg, Frede

    2013-01-01

    Wind turbines are subjected to wind speed variations that cause a power profile that will stress the overall system. This stress is tranfered to the power converter, resulting in temperature variations of the power devices and, hence, causing the reduction of the lifetime. The lifetime expectation changes depending on the real wind speed once the wind turbine is operating. Usually, the real wind speed profiles are employed to evaluate this stress but they do not consider all possible operatio...

  1. 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.

  2. Circuit Regulates Speed Of dc Motor

    Science.gov (United States)

    Weaver, Charles; Padden, Robin; Brown, Floyd A., Jr.

    1990-01-01

    Driving circuit regulates speed of small dc permanent-magnet motor in tape recorder. Two nested feedback loops maintain speed within 1 percent of constant value. Inner loop provides coarse regulation, while outer loop removes most of variation in speed that remains in the presence of regulation by the inner loop. Compares speed of motor with commanded speed and adjusts current supplied to motor accordingly.

  3. 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.

  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. Day-Ahead Wind Speed Forecasting Using Relevance Vector Machine

    Directory of Open Access Journals (Sweden)

    Guoqiang Sun

    2014-01-01

    Full Text Available With the development of wind power technology, the security of the power system, power quality, and stable operation will meet new challenges. So, in this paper, we propose a recently developed machine learning technique, relevance vector machine (RVM, for day-ahead wind speed forecasting. We combine Gaussian kernel function and polynomial kernel function to get mixed kernel for RVM. Then, RVM is compared with back propagation neural network (BP and support vector machine (SVM for wind speed forecasting in four seasons in precision and velocity; the forecast results demonstrate that the proposed method is reasonable and effective.

  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. Unconscious local motion alters global image speed.

    Directory of Open Access Journals (Sweden)

    Sieu K Khuu

    Full Text Available Accurate motion perception of self and object speed is crucial for successful interaction in the world. The context in which we make such speed judgments has a profound effect on their accuracy. Misperceptions of motion speed caused by the context can have drastic consequences in real world situations, but they also reveal much about the underlying mechanisms of motion perception. Here we show that motion signals suppressed from awareness can warp simultaneous conscious speed perception. In Experiment 1, we measured global speed discrimination thresholds using an annulus of 8 local Gabor elements. We show that physically removing local elements from the array attenuated global speed discrimination. However, removing awareness of the local elements only had a small effect on speed discrimination. That is, unconscious local motion elements contributed to global conscious speed perception. In Experiment 2 we measured the global speed of the moving Gabor patterns, when half the elements moved at different speeds. We show that global speed averaging occurred regardless of whether local elements were removed from awareness, such that the speed of invisible elements continued to be averaged together with the visible elements to determine the global speed. These data suggest that contextual motion signals outside of awareness can both boost and affect our experience of motion speed, and suggest that such pooling of motion signals occurs before the conscious extraction of the surround motion speed.

  8. A High Revolution Speed Noncontact Ultrasonic Motor Driven by a Non-Symmetrical Electrode

    Institute of Scientific and Technical Information of China (English)

    YANG Bin; LIU Jing-Quan; CHEN Di; CAI Bing-Chu

    2005-01-01

    @@ A noncontact ultrasonic motor based on a non-symmetrical electrode is proposed. This motor has the advantages of using a simple driving electrode and having a high revolution speed. The revolution speed of its three-blade rotor can reach 5100rpm under a driving voltage of 20 V. A method operated easily is proposed to measure the output torque.

  9. Automatic in-process chatter avoidance in the high-speed milling process

    NARCIS (Netherlands)

    Dijk, N.J.M. van; Doppenberg, E.J.J.; Faassen, R.P.H.; Wouw, N. van de; Oosterling, J.A.J.; Nijmeijer, H.

    2010-01-01

    High-speed milling is often used in industry to maximize productivity of the manufacturing of high-technology components, such as aeronautical components, mold, and dies. The occurrence of chatter highly limits the efficiency and accuracy of high-speed milling operations. In this paper, two control

  10. Design of an Experimental Setup for Testing Multiphysical Effects on High Speed Mini Rotors

    NARCIS (Netherlands)

    Dikmen, Emre; Hoogt, van der Peter J.M.; Boer, de André; Aarts, Ronald G.K.M.; Jonker, Ben

    2011-01-01

    Recently, there have been numerous research projects on the development of minirotating machines. These machines mostly operate at speeds above the first critical speed and have special levitation systems. Besides, the multiphysical effects become significant in small scale. Therefore, advanced mode

  11. Relationship between speed and traffic accident and speed limit on freeway

    Institute of Scientific and Technical Information of China (English)

    CHENG Guo-zhu; PEI Yu-long

    2008-01-01

    To develop an equation between discrete degree of speed and traffic accident on freeway in China and give reasonable suggestions of speed management, the relation model was established between speed standard deviation and accident rate per 100,000,000 vehicle kilometers by regression analysis. The model shows that the more discrete is the speed distribution, the higher is the accident rate, which provides theoretical gist for speed limit on freeway. It is suggested that speed limit should be set according to 85th percentile speed obtained by the relationship between 85th percentile speed and Rcc, (curvature change rate of single circular curve), anddifferent speed limits should be set for cars and trucks. Through analyzing spot speed data of eight freeways in China, regression models were established between 85th percentile speed and RCCs and 15th percentile speed and RCCs. Reasonable speed limit suggestion values are put forward through these models.

  12. Experimental Study of the Influence of Speed and Load on Thermal Behavior of High-Speed Helical Gear Trains

    Science.gov (United States)

    Handschuh, R.; Kilmain, C.

    2005-01-01

    An experimental effort has been conducted on an aerospace-quality helical gear train to investigate the thermal behavior of the gear system as speed, load, and lubricant flow rate were varied. Temperature test data from a helical gear train at varying speeds and loads (to 5000 hp and 15000 rpm) was collected using thermocouple rakes and axial arrays. The instrumentation was able to capture the radial and axial expelled lubricant-air environment (fling-off lubricant) that is expelled during the gear meshing process. Effects of operational characteristics are presented.

  13. Design and Implementation of the DSP-Based V/f Speed Control of an Induction Motor Using Intelligent Controllers

    Directory of Open Access Journals (Sweden)

    H. Rabie

    2012-06-01

    Full Text Available This paper presents experimental results of the V/f speed control for an induction motor under different operating conditions such as step changes in reference speed and the load torque . Genetic PI-based and Fuzzy-Logic-based controllers are considered. Then, the performances of these controllers are experimentally compared with each other under these different operating conditions.

  14. Variable-Speed Instrumented Centrifuges

    Science.gov (United States)

    Chapman, David K.; Brown, Allan H.

    1991-01-01

    Report describes conceptual pair of centrifuges, speed of which varied to produce range of artificial gravities in zero-gravity environment. Image and data recording and controlled temperature and gravity provided for 12 experiments. Microprocessor-controlled centrifuges include video cameras to record stop-motion images of experiments. Potential applications include studies of effect of gravity on growth and on production of hormones in corn seedlings, experiments with magnetic flotation to separate cells, and electrophoresis to separate large fragments of deoxyribonucleic acid.

  15. 49 CFR 38.175 - High-speed rail cars, monorails and systems.

    Science.gov (United States)

    2010-10-01

    ... but not limited to those using “maglev” or high speed steel-wheel-on-steel rail technology, and monorail systems operating primarily on dedicated rail (i.e., not used by freight trains) or guideway,...

  16. Induction generator produces constant-frequency voltage from variable-speed drive

    Science.gov (United States)

    Riaz, M.

    1970-01-01

    Two-stage polyphase generator is usable as induction motor operable over range of speeds while powered from constant frequency source. It requires neither slip rings nor special adjustable-frequency power supplies or external reactive sources.

  17. Demonstration of variable speed permanent magnet generator at small, low-head hydro site

    Energy Technology Data Exchange (ETDEWEB)

    Brown Kinloch, David [Shaker Landing Hydro Associates, Inc., Louisville, KY (United States)

    2015-12-18

    Small hydro developers face a limited set of bad choices when choosing a generator for a small low-head hydro site. Direct drive synchronous generators are expensive and technically complex to install. Simpler induction generators are higher speed, requiring a speed increaser, which results in inefficiencies and maintenance problems. In addition, both induction and synchronous generators turn at a fixed speed, causing the turbine to run off its peak efficiency curve whenever the available head is different than the designed optimum head.The solution to these problems is the variable speed Permanent Magnet Generators (PMG). At the Weisenberger Mill in Midway, KY, a variable speed Permanent Magnet Generator has been installed and demonstrated. This new PMG system replaced an existing induction generator that had a HTD belt drive speed increaser system. Data was taken from the old generator before it was removed and compared to data collected after the PMG system was installed. The new variable speed PMG system is calculated to produce over 96% more energy than the old induction generator system during an average year. This significant increase was primarily due to the PMG generator operating at the correct speed at the maximum head, and the ability for the PMG generator to reduce its speed to lower optimum speeds as the stream flow increased and the net head decreased.This demonstration showed the importance of being able to adjust the speed of fixed blade turbines. All fixed blade turbines with varying net heads could achieve higher efficiencies if the speed can be matched to the optimum speed as the head changes. In addition, this demonstration showed that there are many potential efficiencies that could be realized with variable speed technology at hydro sites where mismatched turbine and generator speeds result in lower power output, even at maximum head. Funding for this project came from the US Dept. of Energy, through Award Number DE-EE0005429.

  18. Overt vs. covert speed cameras in combination with delayed vs. immediate feedback to the offender.

    Science.gov (United States)

    Marciano, Hadas; Setter, Pe'erly; Norman, Joel

    2015-06-01

    Speeding is a major problem in road safety because it increases both the probability of accidents and the severity of injuries if an accident occurs. Speed cameras are one of the most common speed enforcement tools. Most of the speed cameras around the world are overt, but there is evidence that this can cause a "kangaroo effect" in driving patterns. One suggested alternative to prevent this kangaroo effect is the use of covert cameras. Another issue relevant to the effect of enforcement countermeasures on speeding is the timing of the fine. There is general agreement on the importance of the immediacy of the punishment, however, in the context of speed limit enforcement, implementing such immediate punishment is difficult. An immediate feedback that mediates the delay between the speed violation and getting a ticket is one possible solution. This study examines combinations of concealment and the timing of the fine in operating speed cameras in order to evaluate the most effective one in terms of enforcing speed limits. Using a driving simulator, the driving performance of the following four experimental groups was tested: (1) overt cameras with delayed feedback, (2) overt cameras with immediate feedback, (3) covert cameras with delayed feedback, and (4) covert cameras with immediate feedback. Each of the 58 participants drove in the same scenario on three different days. The results showed that both median speed and speed variance were higher with overt than with covert cameras. Moreover, implementing a covert camera system along with immediate feedback was more conducive to drivers maintaining steady speeds at the permitted levels from the very beginning. Finally, both 'overt cameras' groups exhibit a kangaroo effect throughout the entire experiment. It can be concluded that an implementation strategy consisting of covert speed cameras combined with immediate feedback to the offender is potentially an optimal way to motivate drivers to maintain speeds at the

  19. The Speed of Galileon Gravity

    CERN Document Server

    Brax, Philippe; Davis, Anne-Christine

    2015-01-01

    We analyse the speed of gravitational waves in coupled Galileon models with an equation of state $\\omega_\\phi=-1$ now and a ghost-free Minkowski limit. We find that the gravitational waves propagate much faster than the speed of light unless these models are small perturbations of cubic Galileons and the Galileon energy density is sub-dominant to a dominant cosmological constant. In this case, the binary pulsar bounds on the speed of gravitational waves can be satisfied and the equation of state can be close to -1 when the coupling to matter and the coefficient of the cubic term of the Galileon Lagrangian are related. This severely restricts the allowed cosmological behaviour of Galileon models and we are forced to conclude that Galileons with a stable Minkowski limit cannot account for the observed acceleration of the expansion of the universe on their own. Moreover any sub-dominant Galileon component of our universe must be dominated by the cubic term. For such models with gravitons propagating faster than ...

  20. Time-limited optimal dynamics beyond the Quantum Speed Limit

    DEFF Research Database (Denmark)

    Gajdacz, Miroslav; Das, Kunal K.; Arlt, Jan

    2015-01-01

    The quantum speed limit sets the minimum time required to transfer a quantum system completely into a given target state. At shorter times the higher operation speed has to be paid with a loss of fidelity. Here we quantify the trade-off between the fidelity and the duration in a system driven...... by a time-varying control. The problem is addressed in the framework of Hilbert space geometry offering an intuitive interpretation of optimal control algorithms. This approach leads to a necessary criterion for control optimality applicable as a measure of algorithm convergence. The time fidelity trade......-off expressed in terms of the direct Hilbert velocity provides a robust prediction of the quantum speed limit and allows to adapt the control optimization such that it yields a predefined fidelity. The results are verified numerically in a multilevel system with a constrained Hamiltonian, and a classification...

  1. 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.

  2. Motivating inhibition - reward prospect speeds up response cancellation.

    Science.gov (United States)

    Boehler, Carsten N; Hopf, Jens-Max; Stoppel, Christian M; Krebs, Ruth M

    2012-12-01

    Reward prospect has been demonstrated to facilitate various cognitive and behavioral operations, particularly by enhancing the speed and vigor of processes linked to approaching reward. Studies in this domain typically employed task regimes in which participants' overt responses are facilitated by prospective rewards. In contrast, we demonstrate here that even the cancellation of a motor response can be accelerated by reward prospect, thus signifying reward-related benefits on restraint rather than approach behavior. Importantly, this facilitation occurred independent of strategy-related adjustments of response speed, which are known to systematically distort the estimation of response-cancellation speed. The fact that motivational factors can indeed facilitate response inhibition is not only relevant for understanding how motivation and response inhibition interact in healthy participants but also for work on various patient groups that display response-inhibition deficits, suggesting that core differences in the ability to inhibit motor responses have to be differentiated from motivational factors.

  3. Wind speed forecasting in the South Coast of Oaxaca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cadenas, Erasmo [Facultad de Ingenieria Mecanica, Universidad Michoacana de San Nicolas de Hidalgo, Santiago Tapia No. 403, Centro (Mexico); Rivera, Wilfrido [Centro de Investigacion en Energia of the Universidad Nacional Autonoma de Mexico (UNAM), Apartado Postal 34, Temixco 62580, Morelos (Mexico)

    2007-10-15

    Comparison of two techniques for wind speed forecasting in the South Coast of the state of Oaxaca, Mexico is presented in this paper. The Autoregressive Integrated Moving Average (ARIMA) and the Artificial Neural Networks (ANN) methods are applied to a time series conformed by 7 years of wind speed measurements. Six years were used in the formulation of the models and the last year was used to validate and compare the effectiveness of the generated prediction by the techniques mentioned above. Seasonal ARIMA models present a better sensitivity to the adjustment and prediction of the wind speed for this case in particular. Nevertheless, it was shown both developed models can be used to predict in a reasonable way, the monthly electricity production of the wind power stations in La Venta, Oaxaca, Mexico to support the operators of the Electric Utility Control Centre. (author)

  4. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2015-01-01

    Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

  5. Type-2 fuzzy logic control based MRAS speed estimator for speed sensorless direct torque and flux control of an induction motor drive.

    Science.gov (United States)

    Ramesh, Tejavathu; Kumar Panda, Anup; Shiva Kumar, S

    2015-07-01

    In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two adaptation mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first adaptation mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various adaptation mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation.

  6. Systems and methods for vehicle speed management

    Energy Technology Data Exchange (ETDEWEB)

    Sujan, Vivek Anand; Vajapeyazula, Phani; Follen, Kenneth; Wu, An; Forst, Howard Robert

    2016-03-01

    Controlling a speed of a vehicle based on at least a portion of a route grade and a route distance divided into a plurality of route sections, each including at least one of a section grade and section length. Controlling the speed of the vehicle is further based on determining a cruise control speed mode for the vehicle for each of the plurality of route sections and determining a speed reference command of the vehicle based on at least one of the cruise control speed mode, the section length, the section grade, and a current speed.

  7. Improving the Response of a Wheel Speed Sensor by Using a RLS Lattice Algorithm

    Science.gov (United States)

    Hernandez, Wilmar

    2006-01-01

    Among the complete family of sensors for automotive safety, consumer and industrial application, speed sensors stand out as one of the most important. Actually, speed sensors have the diversity to be used in a broad range of applications. In today's automotive industry, such sensors are used in the antilock braking system, the traction control system and the electronic stability program. Also, typical applications are cam and crank shaft position/speed and wheel and turbo shaft speed measurement. In addition, they are used to control a variety of functions, including fuel injection, ignition timing in engines, and so on. However, some types of speed sensors cannot respond to very low speeds for different reasons. What is more, the main reason why such sensors are not good at detecting very low speeds is that they are more susceptible to noise when the speed of the target is low. In short, they suffer from noise and generally only work at medium to high speeds. This is one of the drawbacks of the inductive (magnetic reluctance) speed sensors and is the case under study. Furthermore, there are other speed sensors like the differential Hall Effect sensors that are relatively immune to interference and noise, but they cannot detect static fields. This limits their operations to speeds which give a switching frequency greater than a minimum operating frequency. In short, this research is focused on improving the performance of a variable reluctance speed sensor placed in a car under performance tests by using a recursive least-squares (RLS) lattice algorithm. Such an algorithm is situated in an adaptive noise canceller and carries out an optimal estimation of the relevant signal coming from the sensor, which is buried in a broad-band noise background where we have little knowledge of the noise characteristics. The experimental results are satisfactory and show a significant improvement in the signal-to-noise ratio at the system output.

  8. Assessing variable speed pump efficiency in water distribution systems

    Directory of Open Access Journals (Sweden)

    A. Marchi

    2012-07-01

    Full Text Available Energy savings and greenhouse gas emission reductions are increasingly becoming important design targets in many industrial systems where fossil fuel based electrical energy is heavily utilised. In water distribution systems (WDSs a significant portion of operational cost is related to pumping. Recent studies have considered variable speed pumps (VSPs which aim to vary the operating point of the pump to match demand to pumping rate. Depending on the system characteristics, this approach can lead to considerable savings in operational costs. In particular, cost reductions can take advantage of the demand variability and can decrease energy consumption significantly. One of the issues in using variable speed pumping systems, however, is the total efficiency of the electric motor/pump arrangement under a given operating condition. This paper aims to provide a comprehensive discussion about the components of WDS that incorporate variable speed pumps (including electric motors, variable frequency drives and the pumps themselves to provide an insight of ways of increasing the system efficiency and hence to reduce energy consumption. In addition, specific attention is given to selection of motor types, sizing, duty cycle of pump (ratio of on-time and time period, losses due to installation and motor faults. All these factors affect the efficiency of motor drive/pump system.

  9. Assessing variable speed pump efficiency in water distribution systems

    Directory of Open Access Journals (Sweden)

    A. Marchi

    2012-03-01

    Full Text Available Energy savings and greenhouse gas emission reductions are increasingly becoming important design targets in many industrial systems where fossil fuel based electrical energy is heavily utilised. In water distribution systems (WDSs a significant portion of operational cost is related to pumping. Recent studies have considered variable speed pumps (VSPs which aim to vary the operating point of the pump to match demand to pumping rate. Depending on the system characteristics, this approach can lead to considerable savings in operational costs. In particular, cost reductions can take advantage of the demand variability and can decrease energy consumption significantly. One of the issues in using variable speed pumping systems, however, is the total efficiency of the electric motor/pump arrangement under a given operating condition. This paper aims to provide a comprehensive discussion about the components of WDS that incorporate variable speed pumps (including electric motors, inverters and the pumps themselves to provide an insight of ways of increasing the system efficiency and hence to reduce energy consumption. In addition, specific attention is given to selection of motor types, sizing, duty cycle of pump (ratio of on-time and time period, losses due to installation and motor faults. All these factors affect the efficiency of motor drive/pump system.

  10. Operational amplifiers

    CERN Document Server

    Dostal, Jiri

    1993-01-01

    This book provides the reader with the practical knowledge necessary to select and use operational amplifier devices. It presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits.Provides the reader with practical knowledge necessary to select and use operational amplifier devices. Presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits

  11. Meaningful improvement in gait speed in hip fracture recovery.

    Science.gov (United States)

    Alley, Dawn E; Hicks, Gregory E; Shardell, Michelle; Hawkes, William; Miller, Ram; Craik, Rebecca L; Mangione, Kathleen K; Orwig, Denise; Hochberg, Marc; Resnick, Barbara; Magaziner, Jay

    2011-09-01

    To estimate meaningful improvements in gait speed observed during recovery from hip fracture and to evaluate the sensitivity and specificity of gait speed changes in detecting change in self-reported mobility. Secondary longitudinal data analysis from two randomized controlled trials Twelve hospitals in the Baltimore, Maryland, area. Two hundred seventeen women admitted with hip fracture. Usual gait speed and self-reported mobility (ability to walk 1 block and climb 1 flight of stairs) measured 2 and 12 months after fracture. Effect size-based estimates of meaningful differences were 0.03 for small differences and 0.09 for substantial differences. Depending on the anchor (stairs vs walking) and method (mean difference vs regression), anchor-based estimates ranged from 0.10 to 0.17 m/s for small meaningful improvements and 0.17 to 0.26 m/s for substantial meaningful improvement. Optimal gait speed cutpoints yielded low sensitivity (0.39-0.62) and specificity (0.57-0.76) for improvements in self-reported mobility. Results from this sample of women recovering from hip fracture provide only limited support for the 0.10-m/s cut point for substantial meaningful change previously identified in community-dwelling older adults experiencing declines in walking abilities. Anchor-based estimates and cut points derived from receiver operating characteristic curve analysis suggest that greater improvements in gait speed may be required for substantial perceived mobility improvement in female hip fracture patients. Furthermore, gait speed change performed poorly in discriminating change in self-reported mobility. Estimates of meaningful change in gait speed may differ based on the direction of change (improvement vs decline) or between patient populations. © 2011, Copyright the Authors. Journal compilation © 2011, The American Geriatrics Society.

  12. Evaluating the operations capability of Freedom's Data Management System

    Science.gov (United States)

    Sowizral, Henry A.

    1990-01-01

    Three areas of Data Management System (DMS) performance are examined: raw processor speed, the subjective speed of the Lynx OS X-Window system, and the operational capacity of the Runtime Object Database (RODB). It is concluded that the proposed processor will operate at its specified rate of speed and that the X-Window system operates within users' subjective needs. It is also concluded that the RODB cannot provide the required level of service, even with a two-order of magnitude (100 fold) improvement in speed.

  13. 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.

  14. Speed Control of Induction Motor Using PLC and SCADA System

    Directory of Open Access Journals (Sweden)

    Ayman Seksak Elsaid,

    2016-01-01

    Full Text Available Automation or automatic control is the use of various control systems for operating equipment such as machinery, processes in factories, boilers and heat-treating ovens, switching in telephone networks, steering and stabilization of ships, aircraft and other applications with minimal or reduced human intervention. Some processes have been completely automated. The motor speed is controlled via the driver as an open loop control. To make a more precise closed loop control of motor speed we will use a tachometer to measure the speed and feed it back to the PLC, which compares to the desired value and take a control action, then the signal is transferred to the motor – via driver – to increase / decrease the speed. We will measure the speed of the motor using an incremental rotary encoder by adjusting parameters (PLC, driver and also we need to reduce the overall cost of the system. Our control system will be held using the available Siemens PLC. In addition, we will monitor motor parameters via SCADA system.

  15. Automated Bearing Fault Diagnosis Using 2D Analysis of Vibration Acceleration Signals under Variable Speed Conditions

    Directory of Open Access Journals (Sweden)

    Sheraz Ali Khan

    2016-01-01

    Full Text Available Traditional fault diagnosis methods of bearings detect characteristic defect frequencies in the envelope power spectrum of the vibration signal. These defect frequencies depend upon the inherently nonstationary shaft speed. Time-frequency and subband signal analysis of vibration signals has been used to deal with random variations in speed, whereas design variations require retraining a new instance of the classifier for each operating speed. This paper presents an automated approach for fault diagnosis in bearings based upon the 2D analysis of vibration acceleration signals under variable speed conditions. Images created from the vibration signals exhibit unique textures for each fault, which show minimal variation with shaft speed. Microtexture analysis of these images is used to generate distinctive fault signatures for each fault type, which can be used to detect those faults at different speeds. A k-nearest neighbor classifier trained using fault signatures generated for one operating speed is used to detect faults at all the other operating speeds. The proposed approach is tested on the bearing fault dataset of Case Western Reserve University, and the results are compared with those of a spectrum imaging-based approach.

  16. Rotordynamic Feasibility of a Conceptual Variable-Speed Power Turbine Propulsion System for Large Civil Tilt-Rotor Applications

    Science.gov (United States)

    Howard, Samuel

    2012-01-01

    A variable-speed power turbine concept is analyzed for rotordynamic feasibility in a Large Civil Tilt-Rotor (LCTR) class engine. Implementation of a variable-speed power turbine in a rotorcraft engine would enable high efficiency propulsion at the high forward velocities anticipated of large tilt-rotor vehicles. Therefore, rotordynamics is a critical issue for this engine concept. A preliminary feasibility study is presented herein to address this concern and identify if variable-speed is possible in a conceptual engine sized for the LCTR. The analysis considers critical speed placement in the operating speed envelope, stability analysis up to the maximum anticipated operating speed, and potential unbalance response amplitudes to determine that a variable-speed power turbine is likely to be challenging, but not impossible to achieve in a tilt-rotor propulsion engine.

  17. Assessment of C-Type Darrieus Wind Turbine Under Low Wind Speed Condition

    Science.gov (United States)

    Misaran, M. S.; Rahman, Md. M.; Muzammil, W. K.; Ismail, M. A.

    2017-07-01

    Harvesting wind energy in in a low wind speed region is deem un-economical if not daunting task. Study shows that a minimum cut in speed of 3.5 m/s is required to extract a meaningful wind energy for electricity while a mean speed of 6 m/s is preferred. However, in Malaysia the mean speed is at 2 m/s with certain potential areas having 3 m/s mean speed. Thus, this work aims to develop a wind turbine that able to operate at lower cut-in speed and produce meaningful power for electricity generation. A C-type Darrieus blade is selected as it shows good potential to operate in arbitrary wind speed condition. The wind turbine is designed and fabricated in UMS labs while the performance of the wind turbine is evaluated in a simulated wind condition. Test result shows that the wind turbine started to rotate at 1 m/s compared to a NACA 0012 Darrieus turbine that started to rotate at 3 m/s. The performance of the turbine shows that it have good potential to be used in an intermittent arbitrary wind speed condition as well as low mean wind speed condition.

  18. Design Optimization of a Variable-Speed Power Turbine

    Science.gov (United States)

    Hendricks, Eric S.; Jones, Scott M.; Gray, Justin S.

    2014-01-01

    NASA's Rotary Wing Project is investigating technologies that will enable the development of revolutionary civil tilt rotor aircraft. Previous studies have shown that for large tilt rotor aircraft to be viable, the rotor speeds need to be slowed significantly during the cruise portion of the flight. This requirement to slow the rotors during cruise presents an interesting challenge to the propulsion system designer as efficient engine performance must be achieved at two drastically different operating conditions. One potential solution to this challenge is to use a transmission with multiple gear ratios and shift to the appropriate ratio during flight. This solution will require a large transmission that is likely to be maintenance intensive and will require a complex shifting procedure to maintain power to the rotors at all times. An alternative solution is to use a fixed gear ratio transmission and require the power turbine to operate efficiently over the entire speed range. This concept is referred to as a variable-speed power-turbine (VSPT) and is the focus of the current study. This paper explores the design of a variable speed power turbine for civil tilt rotor applications using design optimization techniques applied to NASA's new meanline tool, the Object-Oriented Turbomachinery Analysis Code (OTAC).

  19. 14 CFR 25.103 - Stall speed.

    Science.gov (United States)

    2010-01-01

    ... standard; (5) The center of gravity position that results in the highest value of reference stall speed... speed. VSR is expressed as: ER26NO02.001 where: VCL MAX = Calibrated airspeed obtained when the load...

  20. Intelligent Speed Adaptation in Company Vehicles

    DEFF Research Database (Denmark)

    Agerholm, Niels; Tradisauskas, Nerius; Waagepetersen, Rasmus;

    2008-01-01

    This paper describes an intelligent speed adaptation project for company vehicles. The intelligent speed adaptation function in the project is both information and incentive, which means that the intelligent speed adaptation equipment gives a warning as well as penalty points if the driver...... is speeding. Each month the driver with that monthpsilas fewest points wins an award. The paper presents results concerning speed attitude on the first three of a planned 12 months test period. In all 26 vehicles and 51 drivers from six companies participate in the project. The key result is that speeding...... is reduced from 18.7% to 7.4% on urban roads with a speed limit of 50 km/h while it is reduced from 18.9% to 4.7% on rural roads with a speed limit of 80 km/h....

  1. Concepts for Multi-Speed Rotorcraft Drive System - Status of Design and Testing at NASA GRC

    Science.gov (United States)

    Stevens, Mark A.; Lewicki, David G.; Handschuh, Robert F.

    2015-01-01

    In several studies and on-going developments for advanced rotorcraft, the need for variable/multi-speed capable rotors has been raised. Speed changes of up to 50 percent have been proposed for future rotorcraft to improve vehicle performance. A rotor speed change during operation not only requires a rotor that can perform effectively over the operating speed/load range, but also requires a propulsion system possessing these same capabilities. A study was completed investigating possible drive system arrangements that can accommodate up to a 50 percent speed change. Key drivers were identified from which simplicity and weight were judged as central. This paper presents the current status of two gear train concepts coupled with the first of two clutch types developed and tested thus far with focus on design lessons learned and areas requiring development. Also, a third concept is presented, a dual input planetary differential as leveraged from a simple planetary with fixed carrier.

  2. 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.

  3. Hanford Site peak gust wind speeds

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, J.V.

    1998-09-29

    Peak gust wind data collected at the Hanford Site since 1945 are analyzed to estimate maximum wind speeds for use in structural design. The results are compared with design wind speeds proposed for the Hanford Site. These comparisons indicate that design wind speeds contained in a January 1998 advisory changing DOE-STD-1020-94 are excessive for the Hanford Site and that the design wind speeds in effect prior to the changes are still appropriate for the Hanford Site.

  4. Deterministic prediction of surface wind speed variations

    OpenAIRE

    Drisya, G. V.; Kiplangat, D. C.; Asokan, K; K. Satheesh Kumar

    2014-01-01

    Accurate prediction of wind speed is an important aspect of various tasks related to wind energy management such as wind turbine predictive control and wind power scheduling. The most typical characteristic of wind speed data is its persistent temporal variations. Most of the techniques reported in the literature for prediction of wind speed and power are based on statistical methods or probabilistic distribution of wind speed data. In this paper we demonstrate that determin...

  5. 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.

  6. 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.

  7. Thermoelasticity with Finite Wave Speeds

    CERN Document Server

    Ignaczak, Józef

    2009-01-01

    Generalized dynamic thermoelasticity is a vital area of research in continuum mechanics, free of the classical paradox of infinite propagation speeds of thermal signals in Fourier-type heat conduction. Besides that paradox, the classical dynamic thermoelasticity theory offers either unsatisfactory or poor descriptions of a solid's response at low temperatures or to a fast transient loading (say, due to short laser pulses). Several models have been developed and intensively studiedover the past four decades, yet this book, which aims to provide a point of reference in the field, is the first mo

  8. Using Appropriate Speed Tables Regarding to the Speed Limit of Streets

    Directory of Open Access Journals (Sweden)

    Amir Falamarzi

    2014-04-01

    Full Text Available In the present decade along the increasing trend of using private vehicles, calming the local streets and residential areas has been important for local authorities. There are many unsuccessful experiences of traffic calming implementations because of lacking knowledge and engineered assessment before implementing them. Considering the design speed of traffic, calming measure is an essential factor to employ these measures. Design speed of different size of speed humps is investigated in previous studies because of its circular shape but for speed tables it is unknown. In this research the design speeds of two common speed tables in the city of Tehran have been examined, 6.5 and 8.5 m speed table. For calculating the design speed of the speed tables, we asked 220 drivers to participate in our experiment by installing a GPS tracker in their vehicles and encouraging them to drive normally. Crossing speeds over 6.5 and 8.5 m speed tables have been analyzed by collecting totally 220 samples. We pick out 100 correct samples for each speed table and the 85th percentile speed has been calculated for them, consequently the results of 85th percentile calculation of the crossing speeds have been proposed as the design speeds. For 6.5 m speed table, design speed is calculated 41.5 km/h and for 8.5 m speed table, design speed is calculated 47.5 km/h. the comparison of recent findings and past finding of 9.5 m speed table which is used in Denmark with a design speed of 80 km/h reveals that 1 m increasing with the length of a 6.5 speed table plateau will result 3 km/h increase in its design speed. The findings of this research can help traffic calming experts to take in consideration of the relation between speed table physical characteristics and its design speed. Furthermore by finding the design speed of speed tables, we can choose suitable speed tables for streets with different speed limits according to the design speed of speed tables.

  9. The History and State of the Art of Variable-Speed Wind Turbine Technology

    Science.gov (United States)

    Carlin, P. W.; Laxson, A. S.; Muljadi, E. B.

    2003-04-01

    Early wind turbines used for performing mechanical work (pumping, grinding and cutting) optimized aerodynamics by being allowed to run at variable speed. Some of the earliest DC electric wind turbines were allowed to run at variable speed. With the advent of grid-connected AC turbines, rotational speeds were limited in order to control the wind turbine AC frequency output to equal the grid frequency. With the advent of semiconductor devices, attempts began as early as the 1970s to allow variable-speed operation of large-scale turbines. The introduction of a new generation of high-voltage, high-speed power electronic components allows a wide range of variable-speed operation for very-large-scale machines. Over the past 30 years a number of designs have been tested, a few of which have entered commercial operation. A number of these designs and their histories are described. A detailed description of a wide range of electrical methods for allowing variable-speed operation is provided.

  10. 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.

  11. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...... dependent of the operating point, which is characterised by the speed and load. If the requirements to the controller performance is large, then it is difficult to maintain specified controller performance with a fixed controller, because of the open loop variations. An auto-tuner based on least squares......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...

  12. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...... dependent of the operating point, which is characterised by the speed and load. If the requirements to the controller performance is large, then it is difficult to maintain specified controller performance with a fixed controller, because of the open loop variations. An auto-tuner based on least squares......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...

  13. Does Extensive Reading Promote Reading Speed?

    Science.gov (United States)

    He, Mu

    2014-01-01

    Research has shown a wide range of learning benefits accruing from extensive reading. Not only is there improvement in reading, but also in a wide range of language uses and areas of language knowledge. However, few research studies have examined reading speed. The existing literature on reading speed focused on students' reading speed without…

  14. 49 CFR 236.811 - Speed, medium.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour. ...

  15. Green maritime transportation: Speed and route optimization

    DEFF Research Database (Denmark)

    Psaraftis, Harilaos N.; Kontovas, Christos A.

    2015-01-01

    Among the spectrum of logistics-based measures for green maritime transportation, this chapter focuses on speed optimization. This involves the selection of an appropriate speed by the vessel, so as to optimize a certain objective. As ship speed is not fixed, depressed shipping markets and/or high...

  16. Reading Speed of Contracted French Braille

    Science.gov (United States)

    Laroche, Louise; Boule, Jacinthe; Wittich, Walter

    2012-01-01

    This study was designed to address three hypotheses: (1) The reading speed of both readers of French braille and readers of French print will be faster in the silent condition; however, this gain in speed will be larger for print readers; (2) Individuals who acquired braille before age 10 will display faster reading speeds at lower error rates…

  17. The relation between speed and crashes.

    NARCIS (Netherlands)

    2006-01-01

    The exact relation between speed and crashes depends on many factors. However, in a general sense the relation is very clear: if on a road the driven speeds become higher, the crash rate will also increase. The crash rate is also higher for an individual vehicle that drives at higher speed than the

  18. 49 CFR 229.117 - Speed indicators.

    Science.gov (United States)

    2010-10-01

    ... normal position under all light conditions. (b) Each speed indicator required shall be tested as soon as... 49 Transportation 4 2010-10-01 2010-10-01 false Speed indicators. 229.117 Section 229.117... § 229.117 Speed indicators. (a) After December 31, 1980, each locomotive used as a...

  19. Generation Speed in Raven's Progressive Matrices Test.

    Science.gov (United States)

    Verguts, Tom; De Boeck, Paul; Maris, Eric

    1999-01-01

    Studied the role of response fluency on results of the Raven's Advanced Progressive Matrices (APM) Test by comparing scores on a test of generation speed (speed of generating rules that govern the items) with APM test performance for 127 Belgian undergraduates. Discusses the importance of generation speed in intelligence. (SLD)

  20. Automatic speed management systems : great safety potential ?

    NARCIS (Netherlands)

    Oei, H.-l.

    1992-01-01

    An account is given of speed management experiments carried out in The Netherlands on four 2-lane rural roads with a speed limit of 80 km/h. The experiment involved an information campaign, warning signs and a radar camera system. Fixed signs advised a speed of between 60 and 80 km/h and an automati

  1. 49 CFR 236.813 - Speed, slow.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Speed, slow. 236.813 Section 236.813 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, slow. A speed not exceeding 20 miles per hour....

  2. 33 CFR 401.28 - Speed limits.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Speed limits. 401.28 Section 401... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Seaway Navigation § 401.28 Speed limits. (a) The maximum speed over the bottom for a vessel of more than 12 m in overall length shall be regulated so as not...

  3. 50 CFR 38.13 - Speed limits.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Speed limits. 38.13 Section 38.13 Wildlife... NATIONAL WILDLIFE REFUGE SYSTEM MIDWAY ATOLL NATIONAL WILDLIFE REFUGE Prohibitions § 38.13 Speed limits. No person on Midway Atoll National Wildlife Refuge will exceed the speed limit for automobiles,...

  4. 36 CFR 1004.21 - Speed limits.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Speed limits. 1004.21 Section... limits. (a) Speed limits in the area administered by the Presidio Trust are as follows: (1) 15 miles per... Presidio Trust roads. (b) The Board may designate a different speed limit upon any Presidio Trust road...

  5. 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

  6. Why Does Light Have a Finite Speed?

    Science.gov (United States)

    Brusca, Stephen

    1985-01-01

    Examines the question "Why does light travel at speed c?", dispelling the widespread qualitative notion that the speed of light results from time delays in the interaction of electric and magnetic fields. Also presents information by which readers can work on their own qualitative insights concerning the speed of light. (JN)

  7. Why Does Light Have a Finite Speed?

    Science.gov (United States)

    Brusca, Stephen

    1985-01-01

    Examines the question "Why does light travel at speed c?", dispelling the widespread qualitative notion that the speed of light results from time delays in the interaction of electric and magnetic fields. Also presents information by which readers can work on their own qualitative insights concerning the speed of light. (JN)

  8. Measurement of the Speed of Gravity

    Institute of Scientific and Technical Information of China (English)

    ZHU Yin

    2011-01-01

    From the Liénard-Wiechert potential in both the gravitational field and the electromagnetic field,it is shown that the propagation speed of gravitational field (waves) can be tested by comparing the measured speed of gravitational force with the measured speed of Coulomb force.

  9. Overall impact of speed-related initiatives and factors on crash outcomes.

    Science.gov (United States)

    D'Elia, A; Newstead, S; Cameron, M

    2007-01-01

    From December 2000 until July 2002 a package of speed-related initiatives and factors took place in Victoria, Australia. The broad aim of this study was to evaluate the overall impact of the package on crash outcomes. Monthly crash counts and injury severity proportions were assessed using Poisson and logistic regression models respectively. The model measured the overall effect of the package after adjusting as far as possible for non-speed road safety initiatives and socio-economic factors. The speed-related package was associated with statistically significant estimated reductions in casualty crashes and suggested reductions in injury severity with trends towards increased reductions over time. From December 2000 until July 2002, three new speed enforcement initiatives were implemented in Victoria, Australia. These initiatives were introduced in stages and involved the following key components: More covert operations of mobile speed cameras, including flash-less operations; 50% increase in speed camera operating hours; and lowering of cameras' speed detection threshold. In addition, during the period 2001 to 2002, the 50 km/h General Urban Speed Limit (GUSL) was introduced (January 2001), there was an increase in speed-related advertising including the "Wipe Off 5" campaign, media announcements were made related to the above enforcement initiatives and there was a speeding penalty restructure. The above elements combine to make up a package of speed-related initiatives and factors. The package represents a broad, long term program by Victorian government agencies to reduce speed based on three linked strategies: more intensive Police enforcement of speed limits to deter potential offenders, i.e. the three new speed enforcement initiatives just described - supported by higher penalties; a reduction in the speed limit on local streets throughout Victoria from 60 km/h to 50 km/h; and provision of information using the mass media (television, radio and billboard) to

  10. Comparison of Global Navigation Satellite System Devices on Speed Tracking in Road (TranSPORT Applications

    Directory of Open Access Journals (Sweden)

    Matej Supej

    2014-12-01

    Full Text Available Global Navigation Satellite Systems (GNSS are, in addition to being most widely used vehicle navigation method, becoming popular in sport-related tests. There is a lack of knowledge regarding tracking speed using GNSS, therefore the aims of this study were to examine under dynamic conditions: (1 how accurate technologically different GNSS measure speed and (2 how large is latency in speed measurements in real time applications. Five GNSSs were tested. They were fixed to a car’s roof-rack: a  smart phone, a wrist watch, a handheld device, a professional system for testing vehicles and a high-end Real Time Kinematics (RTK GNSS. The speed data were recorded and analyzed during rapid acceleration and deceleration as well as at steady speed. The study produced four main findings. Higher frequency and high quality GNSS receivers track speed at least at comparable accuracy to a vehicle speedometer. All GNSS systems measured maximum speed and movement at a constant speed well. Acceleration and deceleration have different level of error at different speeds. Low cost GNSS receivers operating at 1 Hz sampling rate had high latency (up to 2.16 s and are not appropriate for tracking speed in real time, especially during dynamic movements.

  11. Speed Sensorless Induction Motor Drives for Electrical Actuators: Schemes, Trends and Tradeoffs

    Science.gov (United States)

    Elbuluk, Malik E.; Kankam, M. David

    1997-01-01

    For a decade, induction motor drive-based electrical actuators have been under investigation as potential replacement for the conventional hydraulic and pneumatic actuators in aircraft. Advantages of electric actuator include lower weight and size, reduced maintenance and operating costs, improved safety due to the elimination of hazardous fluids and high pressure hydraulic and pneumatic actuators, and increased efficiency. Recently, the emphasis of research on induction motor drives has been on sensorless vector control which eliminates flux and speed sensors mounted on the motor. Also, the development of effective speed and flux estimators has allowed good rotor flux-oriented (RFO) performance at all speeds except those close to zero. Sensorless control has improved the motor performance, compared to the Volts/Hertz (or constant flux) controls. This report evaluates documented schemes for speed sensorless drives, and discusses the trends and tradeoffs involved in selecting a particular scheme. These schemes combine the attributes of the direct and indirect field-oriented control (FOC) or use model adaptive reference systems (MRAS) with a speed-dependent current model for flux estimation which tracks the voltage model-based flux estimator. Many factors are important in comparing the effectiveness of a speed sensorless scheme. Among them are the wide speed range capability, motor parameter insensitivity and noise reduction. Although a number of schemes have been proposed for solving the speed estimation, zero-speed FOC with robustness against parameter variations still remains an area of research for speed sensorless control.

  12. 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.

  13. Speed of Light: same everywhere?

    Science.gov (United States)

    Fleischmann, Hans H.

    2012-03-01

    Analyzing the conceptual-physics consequences and interpretation of Einstein's GR, the spatial dependence of the light velocity, c, is considered - in particular the known disagreement between the ``locally measured'' c = co and the slower average speed predicted and observed in Shapiro's experiments. The usual GR formula for Shapiro's delay time, T, (e.g. (9.91) in James B. Haertle, Gravity, Addison Wesley, 2003, page 214), is essentially identical with a straight-line earth-reflector-and-back integral, using a variable local c = co(1-2M/r). And, a small change of the earth radius, rE will change the total T equivalent to that velocity at r=rE. The locally measured c at the minimum radius, r1, is given by putting the ``earth's'' and ``reflector's'' positions symmetrically around r1, at a distance dx = r1d . In this case, a dx-expansion of formula (9.90) in Haertle leads to a non-Newton delay time, dT = (2.5 M/ r1)dx/co - possibly indicating a small anisotropy of c. Thus, the interpretation of co as a constant locally-measured speed, co, clearly seems inconsistent with accepted GR calculations of the Shapiro-type measurements. Further results will be reported.

  14. 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

  15. Control of variable speed wind turbines with doubly-fed induction generators

    DEFF Research Database (Denmark)

    Hansen, A. D.; Soerensen, Poul; Iov, Florin;

    2004-01-01

    The paper presents an overall control method for variable speed pitch controlled wind turbines with double-feed induction generators (DFIG). Emphasis is on control strategies and algorithms applied at each hierarchical control level of the wind turbine. The objectives of the control system are: 1......) to control the power drawn from the wind turbine in order to track the wind turbine maximum power operation point, 2) to limit the power in case of large wind speeds, and 3) to control the reactive power interchanged between the wind turbine generator and the grid. The present control method is designed...... for normal continuous operations. The strongest feature of the implemented control method is that it allows the turbine to operate with the optimum power efficiency over a wider range of wind speeds. The model of the variable speed, variable pitch wind turbine with doubly-fed induction generator...

  16. Combined Flux Observer With Signal Injection Enhancement for Wide Speed Range Sensorless Direct Torque Control of IPMSM Drives

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Andreescu, G.-D.; Pitic, C.I.;

    2008-01-01

    This paper proposes a motion-sensorless control system using direct torque control with space vector modulation for interior permanent magnet synchronous motor (IPMSM) drives, for wide speed range operation, including standstill. A novel stator flux observer with variable structure uses a combined...... voltage-current model with PI compensator for low-speed operations. As speed increases, the observer switches gradually to a PI compensated closed-loop voltage model, which is solely used at high speeds. High-frequency rotating-voltage injection with a single D-module bandpass vector filter and a phase...

  17. Non-linear backstepping control of five-phase IM drive at low speed conditions-experimental implementation.

    Science.gov (United States)

    Echeikh, Hamdi; Trabelsi, Ramzi; Iqbal, Atif; Bianchi, Nicola; Mimouni, Mohamed Fouizi

    2016-11-01

    In this paper non-linear backstepping control (BSC) is employed for high performance five-phase induction motor drive for low speed operation. The traditional control approaches such as direct torque control and indirect rotor field oriented control introduces stability problem at low speed. The proposed BSC is shown to offer stable operation in the sense of Lyapunov and high dynamics at low speed. Experimental results are provided to present the proprieties of the proposed approach at low speed in terms of stability, torque ripple, desired control performance, achievable dynamics and complexity of implementation etc. Copyright © 2016. Published by Elsevier Ltd.

  18. 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.

  19. 76 FR 8917 - Special Conditions: Gulfstream Model GVI Airplane; Automatic Speed Protection for Design Dive Speed

    Science.gov (United States)

    2011-02-16

    ...; Automatic Speed Protection for Design Dive Speed AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... design features include a high speed protection system. These proposed special conditions contain the... Design Features The GVI is equipped with a high speed protection system that limits nose down...

  20. Behavioural effects of fixed speed cameras on motorways: overall improved speed compliance or kangaroo jumps?

    Science.gov (United States)

    De Pauw, Ellen; Daniels, Stijn; Brijs, Tom; Hermans, Elke; Wets, Geert

    2014-12-01

    The present study evaluates the speed effects of fixed speed cameras on motorways. Two locations with speed cameras were extensively examined in a quasi-experiment: (1) a two-lane motorway and (2) a three-lane motorway, each with a posted speed limit of 120 km/h and sited in Flanders, Belgium. The effect is analysed through a before-and-after comparison of travel speeds. General time trends and fluctuations were controlled through the analysis of the speeds at comparison locations. At each of the two roads, data were gathered at five measurement points from 3 km upstream to 3.8 km downstream of the camera. Three outcomes were analysed: (1) average speed, (2) the odds of drivers exceeding the speed limit and (3) the odds of drivers exceeding the speed limit by more than 10%. Speeds decreased on average by 6.4 km/h at the camera locations. Both the odds of drivers exceeding the speed limit (-80%) and the odds of drivers exceeding the speed limit by more than 10% (-86%) decreased considerably. However, before and beyond the cameras the speeds hardly, if at all, reduced. Moreover, the analyses of the speed profiles before and beyond the cameras show that drivers do slow down quite abruptly before the camera and speed up again after passing the camera. It is concluded that a V-profile is found in the spatial speed distribution for both locations.

  1. Estimating pedestrian speed using aggregated literature data

    Science.gov (United States)

    Bosina, Ernst; Weidmann, Ulrich

    2017-02-01

    Since about 80 years, human walking speed has been measured for different purposes. The comparability of the results of these measurements is low, as the walking speed is influenced by a vast amount of parameters and no standardised measurement conditions exist. This work describes the most important factors influencing walking speed based on existing literature and estimates their impact. For this purpose, all walking speed measurements available in the literature were collected and reviewed. Using this data, the parameter values for different influences were computed and grouped according to their strength, which enables to determine the most important measurement parameters in future walking speed experiments. In addition, standardised measurement conditions are proposed which would provide a baseline for future studies and thus enhance their scientific value. For each of these conditions average walking speeds are calculated and the significance of the walking speed differences was determined.

  2. Unsafe at Any (Wind) Speed?.

    Science.gov (United States)

    Schmidlin, Thomas; Hammer, Barbara; King, Paul; Ono, Yuichi; Miller, L. Scott; Thumann, Gregory

    2002-12-01

    The goal of this research was to examine the relative safety and stability of stationary motor vehicles exposed to severe winds. The focus was on private passenger vehicles. 1) The behavior of two instrumented storm-chase vehicles that were exposed to severe winds, 2) the behavior of 291 vehicles exposed to a tornado, and 3) the wind speed required to upset a sedan and a minivan exposed to winds in a wind tunnel were studied. A wind as strong as 47 m s1 (105 mph) has been measured by a storm-chase pickup truck and 44 m s1 (98 mph) by a storm chase sedan. The vehicles were not adversely affected by the wind. Also studied were 291 vehicles parked outdoors at homes struck by tornadoes, and the behavior of the vehicles was compared to the F-scale damage to the house. At sites with F1 or F2 damage, 72% of the vehicles were not moved by the wind and 96% were not tipped over. At sites with F3 or F4 damage, 50% were not moved by the wind and 82% were not tipped over. Wind tunnel tests on a sedan and minivan showed they were most vulnerable to upset (lifting of one tire from the ground) with wind directions near 45° and 135°, as measured from the front. When modeled with 5° of suspension tilt to the side, the sedan was found to be upset at wind speeds of 51-67 m s1 (115-150 mph), and the minivan was upset at wind speeds of 58-80 m s1 (130-180 mph). Although an underground shelter or sturdy building offer the best protection from severe winds, it is found that a vehicle may be a relatively stable place and may be safer than a mobile home or the outdoors. These findings may warrant changes to public recommendations made during tornado warnings and other severe storm situations.

  3. Operational calculus

    CERN Document Server

    Boehme, Thomas K

    1987-01-01

    Operational Calculus, Volume II is a methodical presentation of operational calculus. An outline of the general theory of linear differential equations with constant coefficients is presented. Integral operational calculus and advanced topics in operational calculus, including locally integrable functions and convergence in the space of operators, are also discussed. Formulas and tables are included.Comprised of four sections, this volume begins with a discussion on the general theory of linear differential equations with constant coefficients, focusing on such topics as homogeneous and non-ho

  4. Operating systems

    CERN Document Server

    Tsichritzis, Dionysios C; Rheinboldt, Werner

    1974-01-01

    Operating Systems deals with the fundamental concepts and principles that govern the behavior of operating systems. Many issues regarding the structure of operating systems, including the problems of managing processes, processors, and memory, are examined. Various aspects of operating systems are also discussed, from input-output and files to security, protection, reliability, design methods, performance evaluation, and implementation methods.Comprised of 10 chapters, this volume begins with an overview of what constitutes an operating system, followed by a discussion on the definition and pr

  5. Performance of twist-coupled blades on variable speed rotors

    Energy Technology Data Exchange (ETDEWEB)

    Lobitz, D.W.; Veers, P.S.; Laino, D.J.

    1999-12-07

    The load mitigation and energy capture characteristics of twist-coupled HAWT blades that are mounted on a variable speed rotor are investigated in this paper. These blades are designed to twist toward feather as they bend with pretwist set to achieve a desirable twist distribution at rated power. For this investigation, the ADAMS-WT software has been modified to include blade models with bending-twist coupling. Using twist-coupled and uncoupled models, the ADAMS software is exercised for steady wind environments to generate C{sub p} curves at a number of operating speeds to compare the efficiencies of the two models. The ADAMS software is also used to generate the response of a twist-coupled variable speed rotor to a spectrum of stochastic wind time series. This spectrum contains time series with two mean wind speeds at two turbulence levels. Power control is achieved by imposing a reactive torque on the low speed shaft proportional to the RPM squared with the coefficient specified so that the rotor operates at peak efficiency in the linear aerodynamic range, and by limiting the maximum RPM to take advantage of the stall controlled nature of the rotor. Fatigue calculations are done for the generated load histories using a range of material exponents that represent materials from welded steel to aluminum to composites, and results are compared with the damage computed for the rotor without twist-coupling. Results indicate that significant reductions in damage are achieved across the spectrum of applied wind loading without any degradation in power production.

  6. Schwartz operators

    Science.gov (United States)

    Keyl, M.; Kiukas, J.; Werner, R. F.

    2016-05-01

    In this paper, we introduce Schwartz operators as a non-commutative analog of Schwartz functions and provide a detailed discussion of their properties. We equip them, in particular, with a number of different (but equivalent) families of seminorms which turns the space of Schwartz operators into a Fréchet space. The study of the topological dual leads to non-commutative tempered distributions which are discussed in detail as well. We show, in particular, that the latter can be identified with a certain class of quadratic forms, therefore making operations like products with bounded (and also some unbounded) operators and quantum harmonic analysis available to objects which are otherwise too singular for being a Hilbert space operator. Finally, we show how the new methods can be applied by studying operator moment problems and convergence properties of fluctuation operators.

  7. Transition Operators

    CERN Document Server

    Alcock-Zeilinger, Judith

    2016-01-01

    In this paper, we give a generic algorithm of the transition operators between Hermitian Young projection operators corresponding to equivalent irreducible representations of SU(N), using the compact expressions of Hermitian Young projection operators derived in a companion paper. We show that the Hermitian Young projection operators together with their transition operators constitute a fully orthogonal basis for the algebra of invariants of $V^{\\otimes m}$ that exhibits a systematically simplified multiplication table. We discuss the full algebra of invariants over $V^{\\otimes 3}$ and $V^{\\otimes 4}$ as explicit examples. In our presentation we make use of various standard concepts such as Young projection operators, Clebsch-Gordan operators, and invariants (in birdtrack notation). We tie these perspectives together and use them to shed light on each other.

  8. Motor Integrated Variable Speed Drives

    DEFF Research Database (Denmark)

    Singh, Yash Veer

    A new trend in the variable speed drives (VSDs) is to develop fully integrated systems, which lead to low-cost products with shorter design cycles. Motor Integrated design of VSDs will reduce cable length to connect drive with machine windings and installation time for end user. The electric drives...... are expected to have minimum effect on grid and motor connected to it, i.e. currents drawn from grid should be within specified limits and currents injecting in to machine should not overheat the machine windings to avoid insulation failure due to harmonics. It is also necessary that electric drives should...... when it comes to the development of any kind of power converter topology for power electronic applications. Concerning the use of a power converter in motor integrated VSDs, the first two mentioned aspects receive an even greater im-portance. Power converter design for integrated drives poses a host...

  9. Determining Ship’s Safe Speed and Best Possible Speed for Sea Voyage Legs

    Directory of Open Access Journals (Sweden)

    Grzegorz Rutkowski

    2016-09-01

    Full Text Available The purpose and scope of this paper is to describe factors to consider when determining the ship’s safe speed as well as the best speed for the sea voyage legs including directions related to vessel speed that are given in ColRegs, voyage orders and charter parties. Author also tried to describe the definition for the following notions: ship maneuvering, ship handling, safe speed, best possible speed for sea voyage legs.

  10. Use of speed profile as surrogate measure: Effect of traffic calming devices on crosstown road safety performance.

    Science.gov (United States)

    Moreno, Ana Tsui; García, Alfredo

    2013-12-01

    Urban road safety management is usually characterized by the lack of sufficient, good quality crash data and low budgets to obtain it even though many traffic accidents occur there. For example, 54 percent of road crashes in Spain take place in urban areas, and 10 percent of urban fatal crashes occur on crosstown roads, which are rural roads that traverse small communities. Traffic calming measures (TCMs) are often implemented on these parts of rural roads that traverse small communities in order to reduce both the frequency and severity of crashes by lowering speeds, but evaluation of their effectiveness has been limited. The objective of this study was to develop a methodology using continuous speed profiles to evaluate the safety effectiveness of TCMs on crosstown roads as part of an integrated system in the absence of historical data. Given the strong relationship between speed and crash experience, safety performance can be related to speed. Consequently, speed can be used indirectly as a surrogate safety measure in the absence of crash and speed data. Two indexes were defined in this study as surrogate safety measures based on the continuous speed profile: Ra and Ea. Ra represents the absolute accumulated speed variations relative to the average speed and is inversely related to accumulated speed uniformity; and Ea represents the accumulated speed variations above the speed limit and is directly related to accumulated speeding. Naturalistic data were collected using GPS trackers for 12 scenarios with different TCM spacings. Then, the indexes were applied to individual observed speed profiles (individual analysis) as well as the operating speed profile (global analysis). The values obtained from individual and global analysis were statistically different. Spacing lower than 110m, which was found optimal from previous research, did not allow drivers to modify their speeds as the accumulated speed uniformity was quite similar regardless of the average operating

  11. The effects of variable speed and drive train component efficiencies on wind turbine energy capture

    Energy Technology Data Exchange (ETDEWEB)

    Fingersh, L.J.; Robinson, M.C.

    1998-05-01

    A wind turbine rotor achieves optimal aerodynamic efficiency at a single tip-speed ratio (TSR). To maintain that optimal TSR and maximize energy capture in the stochastic wind environment, it is necessary to employ variable-speed operation. Conventional constant-speed wind turbines have, in the past, been converted into variable-speed turbines by attaching power electronics to the conventional induction generator and gearbox drive train. Such turbines have shown marginal, if any, improvement in energy capture over their constant-speed counterparts. These discrepancies have been shown to be the result of drive train components that are not optimized for variable-speed operation. Traditional drive trains and power electronic converters are designed to achieve maximum efficiency at full load and speed. However, the main energy producing winds operate the turbine at light load for long periods of time. Because of this, significant losses to efficiency occur. This investigation employs a quasi-static model to demonstrate the dramatic effect that component efficiency curves can have on overall annual energy capture.

  12. Matter Flashed at Ultra Speed

    Science.gov (United States)

    2007-06-01

    Using a robotic telescope at the ESO La Silla Observatory, astronomers have for the first time measured the velocity of the explosions known as gamma-ray bursts. The material is travelling at the extraordinary speed of more than 99.999% of the velocity of light, the maximum speed limit in the Universe. ESO PR Photo 26a/07 ESO PR Photo 26a/07 The REM Telescope "With the development of fast-slewing ground-based telescopes such as the 0.6-m REM telescope at ESO La Silla, we can now study in great detail the very first moments following these cosmic catastrophes," says Emilio Molinari, leader of the team that made the discovery. Gamma-ray bursts (GRBs) are powerful explosions occurring in distant galaxies, that often signal the death of stars. They are so bright that, for a brief moment, they almost rival the whole Universe in luminosity. They last, however, for only a very short time, from less than a second to a few minutes. Astronomers have long known that, in order to emit such incredible power in so little time, the exploding material must be moving at a speed comparable with that of light, namely 300 000 km per second. By studying the temporal evolution of the burst luminosity, it has now been possible for the first time to precisely measure this velocity. Gamma-ray bursts, which are unseen by our eyes, are discovered by artificial satellites. The collision of the gamma-ray burst jets into the surrounding gas generates an afterglow visible in the optical and near-infrared that can radiate for several weeks. An array of robotic telescopes were built on the ground, ready to catch this vanishing emission (see e.g. ESO 17/07). On 18 April and 7 June 2006, the NASA/PPARC/ASI Swift satellite detected two bright gamma-ray bursts. In a matter of a few seconds, their position was transmitted to the ground, and the REM telescope began automatically to observe the two GRB fields, detecting the near-infrared afterglows, and monitored the evolution of their luminosity as a

  13. 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.

  14. A new speed optimization algorithm with application in pickling and rolling line

    Directory of Open Access Journals (Sweden)

    Xiaoyan Zhu

    2016-04-01

    Full Text Available In order to reduce equipment wear and operator pressure, as well as to improve the production efficiency of combined continuous pickling line and tandem cold rolling mill units, four sections’ speeds should be automatically optimized to control the three loopers’ abundance, which include the entry loopers’ entry speed, pickling speed, trimming speed, and tandem cold rolling mill entry speed. According to the optimal speed principle, a new optimization algorithm was proposed based on objective function. In this work, Nelder–Mead simplex method is applied to find the optimal solution by minimizing the objective function. In addition, the calculation of four initial speeds is specified, especially the initial tandem cold rolling mill entry speed. The proposed speed optimization algorithm was successfully applied to a 1450 mm continuous pickling line and tandem cold rolling mill. The acceleration and deceleration are smooth and steady when welding, trimming, or roll changing takes place in practice, the three loopers’ abundance are controlled in suitable range. Results show that the continuous pickling line unit could provide the material in maximum capacity to ensure that the tandem cold rolling mill unit’s production is efficient, and the rolling yield is greatly improved due to the decrease in the number of stops.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Spacecraft operations

    CERN Document Server

    Sellmaier, Florian; Schmidhuber, Michael

    2015-01-01

    The book describes the basic concepts of spaceflight operations, for both, human and unmanned missions. The basic subsystems of a space vehicle are explained in dedicated chapters, the relationship of spacecraft design and the very unique space environment are laid out. Flight dynamics are taught as well as ground segment requirements. Mission operations are divided into preparation including management aspects, execution and planning. Deep space missions and space robotic operations are included as special cases. The book is based on a course held at the German Space Operation Center (GSOC).

  1. Visual processing speed in old age

    DEFF Research Database (Denmark)

    Habekost, Thomas; vogel, asmus; Rostrup, Egill;

    2013-01-01

    of the speed of a particular psychological process that are not confounded by the speed of other processes. We used Bundesen's (1990) Theory of Visual Attention (TVA) to obtain specific estimates of processing speed in the visual system controlled for the influence of response latency and individual variations......Habekost, T., Vogel, A., Rostrup, E., Bundesen, C., Kyllingsbaek, S., Garde, E., Ryberg, C. & Waldemar, G. (2012). Visual processing speed in old age. Scandinavian Journal of Psychology. Mental speed is a common concept in theories of cognitive aging, but it is difficult to get measures...... of the perception threshold. A total of 33 non-demented old people (69-87 years) were tested for the ability to recognize briefly presented letters. Performance was analyzed by the TVA model. Visual processing speed decreased approximately linearly with age and was on average halved from 70 to 85 years. Less...

  2. Speed checks on the CERN site

    CERN Multimedia

    2007-01-01

    In view of the significant number of speeding incidents that have been reported, CERN will shortly start to carry out speed checks on the site. The radar used for this purpose will show drivers the speed measured. The disciplinary measures taken against those exceeding the authorised limit (generally 50 k.p.h.) will include a ban from driving on the site for a minimum of one month. Maximilian Metzger
Secretary-General

  3. Measurement of the absolute speed is possible?

    OpenAIRE

    Shevchenko, Sergey V.; Vladimir V. Tokarevsky

    2016-01-01

    One of popular problems, which  are experimentally studied in physics in a long time, is the testing of the special relativity theory, first of all – measurements of isotropy and constancy of light speed; as well as attempts to determine so called “absolute speed”, i.e. the Earth speed in the absolute spacetime (absolute reference frame), if this spacetime (ARF) exists.  Corresponding experiments aimed at the measuring of proper speed of some reference frame in oth...

  4. To measure the absolute speed is possible?

    OpenAIRE

    Shevchenko, Sergey; Tokarevsky, Vladimir

    2013-01-01

    One of popular problems, which are experimentally studied in physics in a long time, is the testing of the special relativity theory, first of all – measurements of isotropy and constancy of light speed; as well as attempts to determine so called “absolute speed”, i.e. the Earth speed in the absolute spacetime (absolute reference frame), if this spacetime (ARF) exists. Corresponding experiments aimed at the measuring of proper speed of some reference frame in other one, incl...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Pedestrian Crossing Speed: The Case of Malaysia

    Directory of Open Access Journals (Sweden)

    Boon Hoe Goh

    2012-12-01

    Full Text Available Pedestrians are vulnerable road users, and they are always at risk when making their daily trips. Hence, roadway design and traffic’ control devices need to consider pedestrians’ safety. Pedestrian walking speed is fundamental to any roadway and traffic’ control design. Unfortunately, no specific guidelines exist for pedestrian crossing speed in Malaysia. The ultimate goals of this research are to establish the local pedestrian crossing speed and to identify the contributing factors. A total of 1579 samples on pedestrian crossing speed were collected at signalized and non-signalized crosswalks. The Bi-variate analysis (chi-square test was carried out to study statistically the association of the contributing factors. The Bi-variate analysis shows that crosswalk type, age and gender significantly contribute to pedestrian speed in Malaysia. However, lighting (daytime and night-time and race are not contributing to the pedestrians’ speed. Besides, pedestrians at non-signalized crosswalk have significantly faster crossing speed than at signalized crosswalk. Chi-square test also showed that children pedestrians are the fastest group, and elderly pedestrians are the slowest group in terms of pedestrian crossing speed. Moreover, male pedestrians have significantly faster crossing speed than female pedestrians do.

  12. Apparent speed increases at low luminance

    OpenAIRE

    Vaziri-Pashkam, Maryam; Cavanagh, Patrick

    2008-01-01

    To investigate the effect of luminance on apparent speed, subjects adjusted the speed of a low-luminance rotating grating (0.31 cd/m2) to match that of a high-luminance one (1260 cd/m2). Above 4 Hz, subjects overestimated the speed of the low-luminance grating. This overestimation increased as a function of temporal rate and reached 30% around 10 Hz temporal rates. The speed overestimation became significant once the lower luminance was 2.4 log units lower than the high luminance comparison. ...

  13. 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.

  14. Operation REDWING

    Science.gov (United States)

    1956-07-31

    only 16mm cinemascope films would be available after 1 August 1956t Act- tion was taken to modify the screens of the Terrace and Starlite theaters...approximately 900, was in operation throughout the interim and operational period. The Starlite Theater, which seats approximately 600, opened in

  15. OPERATION ASKARI

    African Journals Online (AJOL)

    operation using conventional arms against Swapo Plan, while they were still massed in their .... stationed there was no real threat to our planned operation. the idea was to sow confusion in the minds ...... A four by four transport vehi- cle, based ...

  16. Operational Sequencing

    DEFF Research Database (Denmark)

    Nielsen, Thomas Rosendal; Hustvedt, Kjersti

    2016-01-01

    by Bakhtinian theory, Brian Edmiston developed a solution to this in the 1990s: the principle of ‘dialogic sequencing’. Aiming to escape the conflict between relativism and absolutism, we present an alternative to Edmiston’s approach, based on Niklas Luhmann’s theory of ‘operational closure’: operational...

  17. Business & Operations

    Science.gov (United States)

    Agron, Joe

    2007-01-01

    This article presents an interview with John D. Musso, executive director of the Association of School Business Officials (ASBO) International. Musso talks about trends and issues that will most affect school business and operations in 2007 and beyond. Despite the challenges facing school operations, he believes that the key to being successful at…

  18. Operation crosscheck

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, F. C.

    1964-11-06

    This report consists of three sections covering the three major areas of Lawrence Livermore Laboratory`s participation in Operation Crosscheck. These areas are: Diagnostic Aircraft; Radiochemical Sampling; and Device Assembly and Handling, Barbers Point. The information contained in these sections has been extracted from Crosscheck post-operation reports.

  19. Operational Amplifiers.

    Science.gov (United States)

    Foxcroft, G. E.

    1986-01-01

    Addresses the introduction of low cost equipment into high school and college physical science classes. Examines the properties of an "ideal" operational amplifier and discusses how it might be used under saturated and non-saturated conditions. Notes the action of a "real" operational amplifier. (TW)

  20. Speed-invariant encoding of looming object distance requires power law spike rate adaptation.

    Science.gov (United States)

    Clarke, Stephen E; Naud, Richard; Longtin, André; Maler, Leonard

    2013-08-13

    Neural representations of a moving object's distance and approach speed are essential for determining appropriate orienting responses, such as those observed in the localization behaviors of the weakly electric fish, Apteronotus leptorhynchus. We demonstrate that a power law form of spike rate adaptation transforms an electroreceptor afferent's response to "looming" object motion, effectively parsing information about distance and approach speed into distinct measures of the firing rate. Neurons with dynamics characterized by fixed time scales are shown to confound estimates of object distance and speed. Conversely, power law adaptation modifies an electroreceptor afferent's response according to the time scales present in the stimulus, generating a rate code for looming object distance that is invariant to speed and acceleration. Consequently, estimates of both object distance and approach speed can be uniquely determined from an electroreceptor afferent's firing rate, a multiplexed neural code operating over the extended time scales associated with behaviorally relevant stimuli.

  1. Speed Control System on Marine Diesel Engine Based on a Self-Tuning Fuzzy PID Controller

    Directory of Open Access Journals (Sweden)

    Naeim Farouk

    2012-03-01

    Full Text Available The degree of speed control of ship machinery effects on the economics and optimization of the machinery configuration and operation. All marine vessel ranging need some sort of speed control system to control and govern the speed of the marine diesel engines. This study presents a self-tuning fuzzy PID control system for speed control system of marine diesel engine. The system under consideration is a fourth-order plant with highly dynamic and uncertain environments. The current speed controllers for marine/traction diesel engines based on PID Controller cannot fully handle the uncertainties associated with such dynamic environments. A fuzzy logic control algorithm is used to estimate the PID coefficients in order to handle such uncertainties to produce a better control performance. Simulation tests were established using Simulink of MATLAB. The obtained results have demonstrated the feasibility and effectiveness of the proposed approach. Simulation results are represented in this study.

  2. A high speed data acquisition and processing system for real time data analysis and control

    Science.gov (United States)

    Ferron, J. R.

    1992-11-01

    A high speed data acquisition system which is closely coupled with a high speed digital processor is described. Data acquisition at a rate of 40 million 14 bit data values per second is possible simultaneously with data processing at a rate of 80 million floating point operations per second. This is achieved by coupling a commercially available VME format single board computer based on the Intel i860 microprocessor with a custom designed first-in, first-out memory circuit that transfers data at high speed to the processor board memory. Parallel processing to achieve increased computation speed is easily implemented because the data can be transferred simultaneously to multiple processor boards. Possible applications include high speed process control and real time data reduction. A specific example is described in which this hardware is used to implement a feedback control system for 18 parameters which uses 100 input signals and achieves a 100 μs cycle time.

  3. Fuzzy Logic Based Speed Control System for ThreePhase Induction Motor

    Directory of Open Access Journals (Sweden)

    Marwan A. Badran

    2013-05-01

    Full Text Available Three-phase induction motors have been used in a wide range of industry applications. Using modern technology, the speed of induction motor can be easily controlled by variable frequency drives (VFDs. These drives use high speed power transistors with various switching techniques, mainly PWM schemes. For several decades, conventional control systems were applied to electric drives to control the speed of induction motor. Although conventional controllers showed good results, but they still need tuning to obtain optimum results. The recent proposed control systems use fuzzy logic controller (FLC to enhance the performance of induction motor drives. In this paper, a fuzzy logic based speed control system is presented. The proposed controller has been designed with MATLAB/SIMULINK software, and it was tested for various operating conditions including load disturbance and sudden change of reference speed. The results showed better performance of the proposed controller compared with the conventional PI controller.

  4. Faults Identification and Corrective Actions in Rotating Machinery at Rated Speed

    Directory of Open Access Journals (Sweden)

    Nicolò Bachschmid

    2006-01-01

    Full Text Available Malfunction identification in rotor systems by means of a model based approach in the frequency domain during long lasting speed transients (coast-down procedures in large turbo-generators, where a huge amount of vibration data at different rotating speeds is usually collected, has proved to be very effective. This paper explores the possibility to adapt this method to the situation when the vibration data are available at one rotating speed only, which in real machines is generally the normal operating speed. It results that single speed fault identification can be successful, but does not allow to discriminate between different malfunctions that generate similar symptoms. Neverthless the identification results can be used to define corrective balancing masses.

  5. Variable-Speed Simulation of a Dual-Clutch Gearbox Tiltrotor Driveline

    Science.gov (United States)

    DeSmidt, Hans; Wang, Kon-Well; Smith, Edward C.; Lewicki, David G.

    2012-01-01

    This investigation explores the variable-speed operation and shift response of a prototypical two-speed dual-clutch transmission tiltrotor driveline in forward flight. Here, a Comprehensive Variable-Speed Rotorcraft Propulsion System Modeling (CVSRPM) tool developed under a NASA funded NRA program is utilized to simulate the drive system dynamics. In this study, a sequential shifting control strategy is analyzed under a steady forward cruise condition. This investigation attempts to build upon previous variable-speed rotorcraft propulsion studies by 1) including a fully nonlinear transient gas-turbine engine model, 2) including clutch stick-slip friction effects, 3) including shaft flexibility, 4) incorporating a basic flight dynamics model to account for interactions with the flight control system. Through exploring the interactions between the various subsystems, this analysis provides important insights into the continuing development of variable-speed rotorcraft propulsion systems.

  6. 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.

  7. Generation of Random Wind Speed Profiles for Evaluation of Stress in WT Power Converters

    DEFF Research Database (Denmark)

    Pigazo, Alberto; Qin, Zian; Liserre, Marco;

    2013-01-01

    changes depending on the real wind speed once the wind turbine is operating. Usually, the real wind speed profiles are employed to evaluate this stress but they do not consider all possible operation conditions and require intensive computations. To solve these issues, this paper proposes the generation......Wind turbines are subjected to wind speed variations that cause a power profile that will stress the overall system. This stress is tranfered to the power converter, resulting in temperature variations of the power devices and, hence, causing the reduction of the lifetime. The lifetime expectation...... of random wind speed profiles, based on the measured ones, in order to evaluate the thermal stress of the power devices based on a simplified statistical approach....

  8. High Speed Railway Environment Safety Evaluation Based on Measurement Attribute Recognition Model

    Directory of Open Access Journals (Sweden)

    Qizhou Hu

    2014-01-01

    Full Text Available In order to rationally evaluate the high speed railway operation safety level, the environmental safety evaluation index system of high speed railway should be well established by means of analyzing the impact mechanism of severe weather such as raining, thundering, lightning, earthquake, winding, and snowing. In addition to that, the attribute recognition will be identified to determine the similarity between samples and their corresponding attribute classes on the multidimensional space, which is on the basis of the Mahalanobis distance measurement function in terms of Mahalanobis distance with the characteristics of noncorrelation and nondimensionless influence. On top of the assumption, the high speed railway of China environment safety situation will be well elaborated by the suggested methods. The results from the detailed analysis show that the evaluation is basically matched up with the actual situation and could lay a scientific foundation for the high speed railway operation safety.

  9. High Speed Railway Environment Safety Evaluation Based on Measurement Attribute Recognition Model

    Science.gov (United States)

    Hu, Qizhou; Zhang, Bing

    2014-01-01

    In order to rationally evaluate the high speed railway operation safety level, the environmental safety evaluation index system of high speed railway should be well established by means of analyzing the impact mechanism of severe weather such as raining, thundering, lightning, earthquake, winding, and snowing. In addition to that, the attribute recognition will be identified to determine the similarity between samples and their corresponding attribute classes on the multidimensional space, which is on the basis of the Mahalanobis distance measurement function in terms of Mahalanobis distance with the characteristics of noncorrelation and nondimensionless influence. On top of the assumption, the high speed railway of China environment safety situation will be well elaborated by the suggested methods. The results from the detailed analysis show that the evaluation is basically matched up with the actual situation and could lay a scientific foundation for the high speed railway operation safety. PMID:25435866

  10. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    Science.gov (United States)

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  11. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  12. High speed railway environment safety evaluation based on measurement attribute recognition model.

    Science.gov (United States)

    Hu, Qizhou; Gao, Ningbo; Zhang, Bing

    2014-01-01

    In order to rationally evaluate the high speed railway operation safety level, the environmental safety evaluation index system of high speed railway should be well established by means of analyzing the impact mechanism of severe weather such as raining, thundering, lightning, earthquake, winding, and snowing. In addition to that, the attribute recognition will be identified to determine the similarity between samples and their corresponding attribute classes on the multidimensional space, which is on the basis of the Mahalanobis distance measurement function in terms of Mahalanobis distance with the characteristics of noncorrelation and nondimensionless influence. On top of the assumption, the high speed railway of China environment safety situation will be well elaborated by the suggested methods. The results from the detailed analysis show that the evaluation is basically matched up with the actual situation and could lay a scientific foundation for the high speed railway operation safety.

  13. A study of speed limits and speed control measures for the urban arterial road

    Directory of Open Access Journals (Sweden)

    Wichuda Satiennam

    2015-06-01

    Full Text Available Speed limits in accordance with environment and road functions have been used as a fundamental tool for speed management and road safety. This paper presents literatures review of speed limits measure and results from the study on speed limits problem and driver attitude toward the speed limit and speed control measure. Area of study is on the arterial road where the Mittaprab Highway passed through Khon Kaen City. The study found that improper designation of road functions is the main cause of complexity and difficulty on safety management. It suggests more researches on speed limit setting methods to accommodate the road conditions of the country. In order to increase effectiveness of speed limits measure, this paper suggests transportation-related authorities to classify this area to be the urban arterial road, to set proper speed limits, and to modify the road environment in accordance with its function. More measures to enhance speed limit effectiveness and to reduce accident are included automatic speed control devices, speed limits warning signs, and advertisement signs to use the bypass route. These could enhance the effective speed management program.

  14. 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.

  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. Low Speed PSP Testing in Production Wind Tunnels

    Science.gov (United States)

    Bell, James; Mehta, Rabi; Schairer, Ed; Hand, Larry; Nixon, David (Technical Monitor)

    1998-01-01

    The brightness signal from a pressure-sensitive paint varies inversely with absolute pressure. Consequently high signal-to-noise ratios are required to resolve aerodynamic pressure fields at low speeds, where the pressure variation around an object might only be a few percent of the mean pressure. This requirement is unavoidable, and implies that care must be taken to minimize noise sources present in the measurement. This paper discusses and compares the main noise sources in low speed PSP testing using the "classical" intensity-based single-luminophore technique. These are: temperature variation, model deformation, and lamp drift/paint degradation. Minimization of these error sources from the point of view of operation in production wind tunnels is discussed, with some examples from recent tests in NASA Ames facilities.

  17. 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.

  18. Study into penetration speed during laser cutting of brain tissues.

    Science.gov (United States)

    Yilbas, Z; Sami, M; Patiroglu, T

    1998-01-01

    The applications of CO2 continuous-wave lasers in neurosurgery have become important in recent years. Theoretical considerations of laser applicability in medicine are subsequently confirmed experimentally. To obtain precision operation in the laser cutting process, further theoretical developments and experimental studies need to be conducted. Consequently, in the present study, the heat transfer mechanism taking place during laser-tissue interaction is introduced using Fourier theory. The results obtained from the theoretical model are compared with the experimental results. In connection with this, an experiment is designed to measure the penetration speed during the laser cutting process. The measurement is carried out using an optical method. It is found that both results for the penetration speed obtained from the theory and experiment are in a good agreement.

  19. The speed of Arnold diffusion

    Science.gov (United States)

    Efthymiopoulos, C.; Harsoula, M.

    2013-05-01

    A detailed numerical study is presented of the slow diffusion (Arnold diffusion) taking place around resonance crossings in nearly integrable Hamiltonian systems of three degrees of freedom in the so-called ‘Nekhoroshev regime’. The aim is to construct estimates regarding the speed of diffusion based on the numerical values of a truncated form of the so-called remainder of a normalized Hamiltonian function, and to compare them with the outcomes of direct numerical experiments using ensembles of orbits. In this comparison we examine, one by one, the main steps of the so-called analytic and geometric parts of the Nekhoroshev theorem. Thus: (i) we review and implement an algorithm Efthymiopoulos (2008) [45] for Hamiltonian normalization in multiply resonant domains which is implemented as a computer program making calculations up to a high normalization order. (ii) We compute the dependence of the optimal normalization order on the small parameter ɛ in a specific model and compare the result with theoretical estimates on this dependence. (iii) We examine in detail the consequences of assuming simple convexity conditions for the unperturbed Hamiltonian on the geometry of the resonances and on the phase space structure around resonance crossings. (iv) We discuss the dynamical mechanisms by which the remainder of the optimal Hamiltonian normal form drives the diffusion process. Through these steps, we are led to two main results: (i) We construct in our concrete example a convenient set of variables, proposed first by Benettin and Gallavotti (1986) [12], in which the phenomenon of Arnold diffusion in doubly resonant domains can be clearly visualized. (ii) We determine, by numerical fitting of our data, the dependence of the local diffusion coefficient D on the size ‖R‖ of the optimal remainder function, and we compare this with a heuristic argument based on the assumption of normal diffusion. We find a power law D∝‖, where the constant b has a small positive

  20. Adjustable speed drives: Applications and R&D needs

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovic, V.R.

    1995-09-01

    The largest opportunity for the growth of adjustable speed drives (ASDs) during the next 5-6 years is in pump, fan and compressor (PFC) applications where a constant, fixed speed operation is converted to adjustable speed in order to realize energy savings. Inverter supplied induction motors are and will continue to be predominately used in these applications. Over the long term (10-15 years), the greatest ASD growth is expected in large volume consumer applications: first in hybrid electric vehicles (EVs) and in residential heating, ventilation and air-conditioning (HVAC). Both induction and a variety of AC Permanent Magnet motors are expected to be the dominant technology in this new field. The traditional ASD applications in industries which require adjustable speed (such as machine tools, robotics, steel rolling, extruders, paper mill finishing lines, etc.) offer a relatively limited potential for above average ASD growth since most of these applications have already converted to electronic speed control. As a result, ASD growth in this sector will essentially track the growth of the corresponding industries. If realized, both short and long term ASD growth opportunities will result in significant advancements of ASD technology, which will then substantially affect all other, more fragmented, ASD applications. In fact, any single large volume ASD application will serve as a catalyst for improving ASD characteristics in all other ASD applications with the same voltage rating. ASD cost and reliability (defined in the context of application compatibility) are the two most important factors which will determine whether the ASD growth opportunities are realized. Conversely, any technological improvement which carries a cost increase will be restricted to niche applications, at best. Consequently, future R & D efforts should be directed to secure reduction in ASD cost and improvement in ASD reliability. A specific action plan is outlined in this report.