WorldWideScience

Sample records for delay beam steering

  1. Method of achieving ultra-wideband true-time-delay beam steering for active electronically scanned arrays

    Energy Technology Data Exchange (ETDEWEB)

    Loui, Hung; Brock, Billy C.

    2016-10-25

    The various embodiments presented herein relate to beam steering an array antenna by modifying intermediate frequency (IF) waveforms prior to conversion to RF signals. For each channel, a direct digital synthesis (DDS) component can be utilized to generate a waveform or modify amplitude, timing and phase of a waveform relative to another waveform, whereby the generation/modification can be performed prior to the IF input port of a mixer on each channel. A local oscillator (LO) signal can be utilized to commonly drive each of the mixers. After conversion at the RF output port of each of the mixers, each RF signal can be transmitted by a respective antenna element in the antenna array. Initiation of transmission of each RF signal can be performed simultaneously at each antenna. The process can be reversed during receive whereby timing, amplitude, and phase of the received can be modified digitally post ADC conversion.

  2. Digital Beam Steering Antenna

    Science.gov (United States)

    1988-05-01

    in the budget: 1) RF section amplitude and phase mismatch. 2) RF section time delay mismatch. 3) Image filter out of band rejection. 4) IF section...fras) _ actor dB RF image filter 0.0003 dB & 0.0175’ .999999906 -70.2 RF mixer 0.00019 dB & 0.00133’ .999999999 -89.9 First i-f filter 0.00243 dB

  3. Reconfigurable time-steered array-antenna beam former.

    Science.gov (United States)

    Frankel, M Y; Esman, R D

    1997-12-10

    We present and analyze a hardware-optimized technique that provides true-time-delay steering for broadband two-dimensional array-antenna applications. The technique improves on previous approaches by the reduction of the two-dimensional beam-former architecture complexity, by the provision of flexibility in time-delay unit selection, and by the potential reduction of optical loss. The technique relies on a one-dimensional bank of time-delay units to form the required time-delay gradient for proper off-broadside angle steering. A reconfigurable optical interconnection fabric is used to reassign dynamically the connections between the time-delay units and individual array elements of a two-dimensional array to effect the proper steering angle along the off-broadside cone.

  4. Self-steering partially coherent beams

    Science.gov (United States)

    Chen, Yahong; Ponomarenko, Sergey A.; Cai, Yangjian

    2017-01-01

    We introduce a class of shape-invariant partially coherent beams with a moving guiding center which we term self-steering partially coherent beams. The guiding center of each such beam evolves along a straight line trajectory which can be engineered to make any angle with the x-axis. We show that the straight line trajectory of the guiding center is the only option in free space due to the linear momentum conservation. We experimentally generate a particular subclass of new beams, self-steering Gaussian Schell beams and argue that they can find applications for mobile target tracing and trapped micro- and/or nanoparticle transport. PMID:28051164

  5. Tunable beam steering enabled by graphene metamaterials.

    Science.gov (United States)

    Orazbayev, B; Beruete, M; Khromova, I

    2016-04-18

    We demonstrate tunable mid-infrared (MIR) beam steering devices based on multilayer graphene-dielectric metamaterials. The effective refractive index of such metamaterials can be manipulated by changing the chemical potential of each graphene layer. This can arbitrarily tailor the spatial distribution of the phase of the transmitted beam, providing mechanisms for active beam steering. Three different beam steerer (BS) designs are discussed: a graded-index (GRIN) graphene-based metamaterial block, an array of metallic waveguides filled with graphene-dielectric metamaterial and an array of planar waveguides created in a graphene-dielectric metamaterial block with a specific spatial profile of graphene sheets doping. The performances of the BSs are numerically analyzed, showing the tunability of the proposed designs for a wide range of output angles (up to approximately 70°). The proposed graphene-based tunable beam steering can be used in tunable transmitter/receiver modules for infrared imaging and sensing.

  6. SPS Beam Steering for LHC Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Gianfelice-Wendt, Eliana [Fermilab; Bartosik, Hannes [CERN; Cornelis, Karel [CERN; Norderhaug Drøsdal, Lene [CERN; Goddard, Brennan [CERN; Kain, Verena [CERN; Meddahi, Malika [CERN; Papaphilippou, Yannis [CERN; Wenninger, Jorg [CERN

    2014-07-01

    The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

  7. SPS Beam Steering for LHC Extraction

    CERN Document Server

    Gianfelice Wendt, E; Cornelis, K; Norderhaug Drosdal, L; Goddard, B; Kain, V; Meddahi, M; Papaphilippou, Y; Wenninger, J

    2014-01-01

    Beside producing beams for fixed target operation, the CERN Super Proton Synchrotron (SPS) accelerates beams for injection into the Large Hadron Collider (LHC). During the 2012-2013 run drifts of the extracted beam horizontal trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. The feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, has been therefore investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed. As the observed drift is mainly horizontal, the horizontal plane only will be considered.

  8. Indexing system for optical beam steering

    Science.gov (United States)

    Sullivan, Mark T.; Cannon, David M.; Debra, Daniel B.; Young, Jeffrey A.; Mansfield, Joseph A.; Carmichael, Roger E.; Lissol, Peter S.; Pryor, G. M.; Miklosy, Les G.; Lee, Jeffrey H.

    1990-01-01

    This paper describes the design and testing of an indexing system for optical-beam steering. The cryogenic beam-steering mechanism is a 360-degree rotation device capable of discrete, high-precision alignment positions. It uses low-precision components for its rough alignment and kinematic design to meet its stringent repeatability and stability requirements (of about 5 arcsec). The principal advantages of this design include a decoupling of the low-precision, large angular motion from the high-precision alignment, and a power-off alignment position that potentially extends the life or hold time of cryogenic systems. An alternate design, which takes advantage of these attributes while reducing overall motion, is also presented. Preliminary test results show the kinematic mount capable of sub-arc second repeatability.

  9. Phase shifter for antenna beam steering

    Science.gov (United States)

    Jindal, Ravi; Razban, Tchanguiz

    2016-03-01

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  10. Phase shifter for antenna beam steering

    Energy Technology Data Exchange (ETDEWEB)

    Jindal, Ravi, E-mail: rjindal21@gmail.com [Master’s(MS) in System Electronics and General Electrical, Ecole Polytechnique of university of Nantes France, IETR, Nantes (France); Razban, Tchanguiz, E-mail: tchanguiz.razban-haghighi@univ-nantes.fr [Electronics and Telecommunication Institute of Rennes (IETR-UMR 6164), Ecole Polytechnique of university of Nantes France, IETR, Nantes (France)

    2016-03-09

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  11. Beam Steering Mechanism (BSM) Lessons Learned

    Science.gov (United States)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gostin, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. High resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of methodology to verify performance was a significant effortadvancement. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite 2 Mission (ICESat 2), which is scheduled to be launched in 2017. The ICESat 2 primary mission is to map the earths surface topography for the determination of seasonal changes of ice sheet thickness as well as vegetation canopy thickness.

  12. ATLAS Beam Steering Mechanism (BSM) Lessons Learned

    Science.gov (United States)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gosten, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. The high resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of the methodology to verify performance required significant effort. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite II Mission (ICESat II), which is scheduled to be launched in 2017. The ICESat II primary mission is to map the Earth's surface topography for the determination of seasonal changes of ice sheet thickness and vegetation canopy thickness to establish long-term trends.

  13. ATLAS Beam Steering Mechanism Lessons Learned

    Science.gov (United States)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gostin, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morrell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. The high resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of the methodology to verify performance required significant effort. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite II Mission (ICESat II), which is scheduled to be launched in 2017. The ICESat II primary mission is to map the earth's surface topography for the determination of seasonal changes of ice sheet thickness and vegetation canopy thickness to establish long-term trends.

  14. Repositioning and steering laser beam power via coherent combination of multiple Airy beams.

    Science.gov (United States)

    Zhang, Ze; Ye, Zhuoyi; Song, Daohong; Zhang, Peng; Chen, Zhigang

    2013-12-10

    We study numerically and experimentally laser coherent combination (LCC) with multiple one- or two-dimensional Airy beams. It is shown that the method of LCC using Airy beams leads to a higher combining efficiency and a better feature of propagation than that using conventional Gaussian beams. Based on such coherent Airy beams combination, we propose a laser steering approach that could achieve large-angle beam steering (over 0.6°) without the need of using any mechanical steering component.

  15. Design and Analysis of a Fast Steering Mirror for Precision Laser Beams Steering

    Directory of Open Access Journals (Sweden)

    Qingkun ZHOU

    2009-03-01

    Full Text Available Precision laser beam steering is critical in numerous applications. Also, precise pointing of laser beams is essential in challenging environments. The optical signal may be deflected, drift and wander due to environmental influences. The core problem of steering performances is to deal with the jitter disturbance. Based on the analysis of the beam angle steering system, some important factors to design the structure of a Fast Steering Mirror (FSM and the layout of laser optics steering system are presented. Flexure hinges with compliant mechanisms are used to build the FSM structure. A 4-quadrant detector is used as the sensor for the incoming light. A design of the developed control loop and concepts of the FSM model are discussed. A comparison between the measured gain response and the simulation model of the FSM reveals similarity between the theoretical simulation model and the real system, and offers a way to improve the model to better resemble the real system. A laser beam jitter control test bed is also introduced to improve jitter control techniques.

  16. Frequency Invariant Beam Steering for Short-Pulse Systems with a Rotman Lens

    Directory of Open Access Journals (Sweden)

    Andreas Lambrecht

    2010-01-01

    Full Text Available A promising approach for beam steering of high-voltage transient signals for HPEM-systems (High Power Electro Magnetic is presented. The inherent capability of the Rotman lens to provide true time delays is used to develop a prototype beam steering device for an antielectronics HPEM system in the frequency range from 350 MHz to 5 GHz. Results of analytical calculations, simulations, and measurements from a hardware prototype are presented. The detailed mechanical setup of the Rotman lens is presented. Additionally the output pulses are investigated when inputting a Gaussian-like transient signal. Then time domain measures of quality (full width at half maximum, ringing, delay spread, maximum of transfer function are investigated for these output transients, and the simulation and measurement results are compared. A concluding analysis of the realizable time domain array pattern shows the radiated pulse form.

  17. Image Processing In Laser-Beam-Steering Subsystem

    Science.gov (United States)

    Lesh, James R.; Ansari, Homayoon; Chen, Chien-Chung; Russell, Donald W.

    1996-01-01

    Conceptual design of image-processing circuitry developed for proposed tracking apparatus described in "Beam-Steering Subsystem For Laser Communication" (NPO-19069). In proposed system, desired frame rate achieved by "windowed" readout scheme in which only pixels containing and surrounding two spots read out and others skipped without being read. Image data processed rapidly and efficiently to achieve high frequency response.

  18. Amplitude controlled array transducers for mode selection and beam steering of guided waves in plates

    Science.gov (United States)

    Kannajosyula, H.; Lissenden, C. J.; Rose, J. L.

    2013-01-01

    We present a method for mode selection of guided wave modes and beam steering using purely amplitude variation across a one dimensional linear array of transducers. The method is distinct from apodization of phased array transducers that involves amplitude variation in addition to time delays and merely aims to improve the spectral characteristics of the transducer. The relationship between amplitude variation and the pitch of the array is derived by considering the resulting transduction as analogous to a spatio-temporal filter approach. It is also shown analytically and through numerical examples that the proposed method results in bidirectional guided waves when the steering angle is zero. Further, for non-zero steering angles, the waves travel in four directions, including the desired direction. Experimental studies are suggested.

  19. Oblique incidence effect on steering efficiency of liquid crystal polarization gratings used for optical phased array beam steering amplification

    Science.gov (United States)

    Xiangjie, Zhao; Jiazhu, Duan; Dayong, Zhang; Cangli, Liu; Yongquan, Luo

    2016-07-01

    A liquid crystal polarization grating (LCPG) is proposed that amplifies the steering angle of a liquid crystal optical phased array for non-mechanical beam steering, taking advantage of its high steering efficiency under normal incidence. However, oblique incidence may play an important role in the overall steering efficiency. The effect of oblique incidence on steering efficiency of a LCPG was analyzed by numerically solving the extended Jones matrix and considering propagation crosstalk. The results indicate that the outgoing laser beam is amplitude-modulated under the effect of oblique incidence and behaves as a sinusoidal-modulated amplitude grating, which diffracts certain energies to non-blazed orders. Over-oblique incidence may even eliminate the steering effect of the incident beam. The modulation depth of the induced amplitude grating was found to be proportional to the product of sinusoidal value of oblique incidence angle and the LC layer thickness, and inversely proportional to the periodic pitch length of the LCPG. Both in-plane incidence and out-of-plane incidence behave similarly to influence the steering efficiency. Finally, the overall steering efficiency for cascaded LCPGs was analyzed and a difference of up to 11 % steering efficiency can be induced between different LCPG configurations, even without considering the over-oblique incidence effect. Both the modulation depth and final steering efficiency can be optimized by varying the LC birefringence and layer thickness.

  20. Oblique incidence effect on steering efficiency of liquid crystal polarization gratings used for optical phased array beam steering amplification

    Science.gov (United States)

    Xiangjie, Zhao; Jiazhu, Duan; Dayong, Zhang; Cangli, Liu; Yongquan, Luo

    2016-10-01

    A liquid crystal polarization grating (LCPG) is proposed that amplifies the steering angle of a liquid crystal optical phased array for non-mechanical beam steering, taking advantage of its high steering efficiency under normal incidence. However, oblique incidence may play an important role in the overall steering efficiency. The effect of oblique incidence on steering efficiency of a LCPG was analyzed by numerically solving the extended Jones matrix and considering propagation crosstalk. The results indicate that the outgoing laser beam is amplitude-modulated under the effect of oblique incidence and behaves as a sinusoidal-modulated amplitude grating, which diffracts certain energies to non-blazed orders. Over-oblique incidence may even eliminate the steering effect of the incident beam. The modulation depth of the induced amplitude grating was found to be proportional to the product of sinusoidal value of oblique incidence angle and the LC layer thickness, and inversely proportional to the periodic pitch length of the LCPG. Both in-plane incidence and out-of-plane incidence behave similarly to influence the steering efficiency. Finally, the overall steering efficiency for cascaded LCPGs was analyzed and a difference of up to 11 % steering efficiency can be induced between different LCPG configurations, even without considering the over-oblique incidence effect. Both the modulation depth and final steering efficiency can be optimized by varying the LC birefringence and layer thickness.

  1. Combining the switched-beam and beam-steering capabilities in a 2-D phased array antenna system

    Science.gov (United States)

    Tsai, Yi-Che; Chen, Yin-Bing; Hwang, Ruey-Bing

    2016-01-01

    This paper presents the development, fabrication, and measurement of a novel beam-forming system consisting of 16 subarray antennas, each containing four aperture-coupled patch antennas, and the application of this system in smart wireless communication systems. The beam patterns of each of the subarray antennas can be switched toward one of nine zones over a half space by adjusting the specific phase delay angles among the four antenna elements. Furthermore, when all subarrays are pointed at the same zone, slightly continuous beam steering in around 1° increments can be achieved by dynamically altering the progressive phase delay angle among the subarrays. Phase angle calibration was implemented by coupling each transmitter output and down converter into the in-phase/quadrature baseband to calculate the correction factor to the weight. In addition, to validate the proposed concepts and the fabricated 2-D phased array antenna system, this study measured the far-field radiation patterns of the aperture-coupled patch array integrated with feeding networks and a phase-calibration system to carefully verify its spatially switched-beam and beam-steering characteristics at a center frequency of 2.4 GHz which can cover the industrial, scientific, and medical band and some long-term evolution applications. In addition, measured results were compared with calculated results, and agreement between them was observed.

  2. Low-Absorption Liquid Crystals for Infrared Beam Steering

    Science.gov (United States)

    2015-09-30

    absorption coefficient and d is the LC layer thickness . Let us take a~!0/cm as an example. For a 10-|j,m- thick LC layer, ad=0.01 and the transmittance...remains 99%. However, if the LC layer thickness (or effective optical path length) increases, then the absorption will increase exponentially, as Eq. (1...weight-and-power, 2) increasing mean-time-between- failure, and 3) reducing system complexity. Beam steering based on liquid crystal ( LC ) optical phase

  3. Theoretical modeling on the laser induced effect of liquid crystal optical phased beam steering

    Science.gov (United States)

    He, Xiaoxian; Wang, Xiangru; Wu, Liang; Tan, Qinggui; Li, Man; Shang, Jiyang; Wu, Shuanghong; Huang, Ziqiang

    2017-01-01

    Non-mechanical laser beam steering has been reported previously in liquid crystal array devices. To be one of the most promising candidates to be practical non-mechanical laser deflector, its laser induced effect still has few theoretical model. In this paper, we propose a theoretical model to analyze this laser induced effect of LC-OPA to evaluate the deterioration on phased beam steering. The model has three parts: laser induced thermal distribution; temperature dependence of material parameters and beam steering deterioration. After these three steps, the far field of laser beam is obtained to demonstrate the steering performance with the respect to the incident laser beam power and beam waist.

  4. PERFORMANCE ANALYSIS OF AZIMUTH ELECTRONIC BEAM STEERING MODE SPACEBORNE SAR

    Institute of Scientific and Technical Information of China (English)

    Han Xiaodong; Xu Wei; Han Xiaolei

    2013-01-01

    Pointing angle and pattern of the antenna can be changed swiftly to actualize the azimuth beam scanning by using electronic beam steering,which makes the Synthetic Aperture Radar (SAR)system more flexible and achieve a high resolution or cover a long strip within short time span.When the pointing angle is steered away from boresight,some aberrations may appear on the antenna pattern,e.g.,the grating lobe appears,the main lobe gain decrease,and antenna pattern broadens,e.g.,the aberrations result in the worsening of system performance,and complicate the corresponding performance analysis method.Conventional computation methods of performance parameters do not account for the rapid change of the antenna pattern.It introduces remarkable errors when the scanning angle is large.In this paper,a method of calculating performance parameters is proposed for the beam steering mode,which achieves the parameters by the energy accumulation in time domain.Actually,the proposed method simulates the working process of SAR and obtains accurate performance parameters.Furthermore,we analyze the effects of the grating lobe on the Azimuth Ambiguity to Signal Ratio (AASR),and present the generic Pulse Repetition Frequency (PRF) choosing principle which can also prevent the ambiguous area from weighting by the grating lobe.Finally,the effect of the antenna configuration on the performance parameters is analyzed by a system example.

  5. Data transfer through beam steering using agile lensing

    Science.gov (United States)

    Arshad, Muhammad Assad; Reza, Syed Azer; Muhammad, Ahsan

    2016-04-01

    This paper presents a data transfer scheme using multi-focus tunable lenses. The design involves the use of a standard laser source and a variable focus agile lens to steer to the laser beam that passes through the lens. In our proposed system, the beam steer angle depends on an input electrical signal which drives the tunable lens. Therefore the beam steer angle is made to follow the variations in the input electrical drive signal. This is extremely interesting for data transfer applications as the data signal can be used as the input drive signal to the lens. The laser beam is steered according to the input data voltage levels and when the beam is incident on a photo-detector of a finite size, only a fraction of its total incident optical power is received by the photo-detector. This power contribution is proportional to the fraction of the total number of photons per unit area which are incident on the active area of the detector. The remaining photons which are not incident on the photo-detector do not contribute to the received power at the photo-detector. We present the theory of beam steering through a tunable lens and present a theoretical framework which governs data transfer through the proposed method. We also present the transfer function of the proposed system which helps us to calculate its essential theoretical performance parameters such as modulation depth and bit error rates. We also present experimental results to demonstrate efficient data transfer through the proposed method. As tunable lenses are primarily deployed in motion-free multi-focus cameras hence most of the modern portable devices such as cellphones and tablets use these lenses to operate the in-built variable focus cameras that are part of these devices. Because tunable lenses are commonly present in several different portable devices, the proposed method of data transfer between two devices is highly promising as it expands the use of the already deployed tunable lenses with

  6. Architectural evaluation of beam-steered shuffle optical interconnect

    Science.gov (United States)

    Murdocca, Miles J.; Batchu, Ravi V.; Dennison, Michael

    1996-06-01

    We report on a reconfigurable optical interconnection approach in which static communication graphs are extracted from high level programs and are mapped onto a two stage optical beam-steered/perfect shuffle interconnect. An array of processing elements (PEs) is partitioned into functional units of equal size that are served by one optical input/output (I/O) port per PE. PEs within a functional unit can use any of the optical I/O ports served by that functional unit. An optical beam-steering mechanism in conjunction with an optical perfect shuffle interconnects the functional units. At the highest level, computer programs are written in the Id dataflow programming language. At the next level, dataflow graphs (communication graphs that represent the natural parallelism in a computation) are automatically extracted from the high-level programs. At the lowest level, the dataflow graphs are mapped onto the optical beam-steered/perfect shuffle interconnect. This mapping step is facilitated by a mechanism that redirects optical beams to that the physical interconnect takes the form of the dataflow graph. An intended application is to create low latency realizations of specialized hardware on-the-fly, such as for rapid prototyping. An advantage of this approach over competing all-electronic or static free-space optical interconnection approaches is that the optical interconnect has low depth (two stages) with low fan-out (typically 1 to 3). In previous work, the behaviors of the mappings are studied for randomly generated dataflow graphs. In the work reported here, the behaviors of the mappings are studied for extracted dataflow graphs. We conclude that this interconnection approach is effective for extracted dataflow graphs, using only a single pass through the network, if the interconnect is augmented with a small crossbar within each functional unit.

  7. A Novel Microwave Beam Steering Technique Using Plasma

    Science.gov (United States)

    Linardakis, Peter; Borg, Gerard G.; Harris, Jeffrey H.; Martin, Noel M.

    2002-10-01

    At frequencies above the plasma frequency, electromagnetic waves propagate through plasma with a wavelength longer than the free space wavelength. As a result, a plasma with a centrally peaked density profile can deflect rather than focus electromagnetic waves. We present a plasma device designed specifically to deflect a microwave beam as an alternative to conventional beam deflectors based on antenna arrays. A 22^rc deflection of Ka band microwave has been achieved using a laboratory plasma, with no detrimental effect on the beamwidth or side-lode level and structure. The use of a simple WKB model shows agreement and that the deflection can be increased with appropriate design. Results indicate the potential for increases in dynamic range, in power handling (for example from a gyrotron) and for the reduction of insertion losses over current beam steering systems. A ``plasma lens'' demonstrator device has also been designed to test practical performance aspects such as phase noise and to test optimization parameters.

  8. Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces

    Science.gov (United States)

    Hashemi, Mohammed Reza M.; Yang, Shang-Hua; Wang, Tongyu; Sepúlveda, Nelson; Jarrahi, Mona

    2016-10-01

    Engineered metamaterials offer unique functionalities for manipulating the spectral and spatial properties of electromagnetic waves in unconventional ways. Here, we report a novel approach for making reconfigurable metasurfaces capable of deflecting electromagnetic waves in an electronically controllable fashion. This is accomplished by tilting the phase front of waves through a two-dimensional array of resonant metasurface unit-cells with electronically-controlled phase-change materials embedded inside. Such metasurfaces can be placed at the output facet of any electromagnetic radiation source to deflect electromagnetic waves at a desired frequency, ranging from millimeter-wave to far-infrared frequencies. Our design does not use any mechanical elements, external light sources, or reflectarrays, creating, for the first time, a highly robust and fully-integrated beam-steering device solution. We demonstrate a proof-of-concept beam-steering metasurface optimized for operation at 100 GHz, offering up to 44° beam deflection in both horizontal and vertical directions. Dynamic control of electromagnetic wave propagation direction through this unique platform could be transformative for various imaging, sensing, and communication applications, among others.

  9. Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces

    Science.gov (United States)

    Hashemi, Mohammed Reza M.; Yang, Shang-Hua; Wang, Tongyu; Sepúlveda, Nelson; Jarrahi, Mona

    2016-01-01

    Engineered metamaterials offer unique functionalities for manipulating the spectral and spatial properties of electromagnetic waves in unconventional ways. Here, we report a novel approach for making reconfigurable metasurfaces capable of deflecting electromagnetic waves in an electronically controllable fashion. This is accomplished by tilting the phase front of waves through a two-dimensional array of resonant metasurface unit-cells with electronically-controlled phase-change materials embedded inside. Such metasurfaces can be placed at the output facet of any electromagnetic radiation source to deflect electromagnetic waves at a desired frequency, ranging from millimeter-wave to far-infrared frequencies. Our design does not use any mechanical elements, external light sources, or reflectarrays, creating, for the first time, a highly robust and fully-integrated beam-steering device solution. We demonstrate a proof-of-concept beam-steering metasurface optimized for operation at 100 GHz, offering up to 44° beam deflection in both horizontal and vertical directions. Dynamic control of electromagnetic wave propagation direction through this unique platform could be transformative for various imaging, sensing, and communication applications, among others. PMID:27739471

  10. Laser beam steering approaches for microstructuring of copper layers

    Science.gov (United States)

    Mur, Jaka; Podobnik, Boštjan; Poberaj, Igor

    2017-02-01

    We have investigated the process of copper layer ablation with a tightly focused Q-switched 532 nm laser. Focusing 40 ns long laser pulses to a micrometer-sized spot results in high energy density and gives rise to ablation phenomena not seen during laser processing with larger beam diameters. Use of acousto-optic deflectors (AODs) enabled us to test different laser beam steering approaches in terms of choosing the position for each laser pulse independently of the previous pulses. Random addressing of desired positions across a microstructure proved to be the most efficient method compared to various scanning approaches. Assigning a random order to the spatial sequence of laser pulses resulted in the fastest microstructuring process and featured lowest residual heating of the substrate.

  11. Dynamic steering beams for efficient force measurement in optical manipulation

    Institute of Scientific and Technical Information of China (English)

    Xiaocong Yuan; Yuquan Zhang; Rui Cao; Xing Zhao; Jing Bu; Siwei Zhu

    2011-01-01

    @@ An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported.Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions, respectively, in a viscous medium.The trapped bead will be rotated following the beam's motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force.The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead.The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications.%An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported. Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions, respectively, in a viscous medium. The trapped bead will be rotated following the beam's motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force. The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead. The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications.

  12. Beam steering for circular switched parasitic arrays using a combinational approach

    CSIR Research Space (South Africa)

    Mofolo, ROM

    2011-09-01

    Full Text Available In this paper, the authors present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic...

  13. Acoustic Prism for Continuous Beam Steering Based on Piezoelectric Metamaterial

    CERN Document Server

    Xu, Jiawen

    2016-01-01

    This paper investigates an acoustic prism for continuous acoustic beam steering by a simple frequency sweep. This idea takes advantages of acoustic wave velocity shifting in metamaterials in the vicinity of local resonance. We apply this concept into the piezoelectric metamaterial consisting of host medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are carried out. It is shown that the phase velocity of acoustic wave changes dramatically in the vicinity of local resonance. The directions of acoustic wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of the excitation frequency. Such an electro-mechanical coupling system has a feature of adjusting local resonance without altering the mechanical part of the system.

  14. Beam steering and impedance matching of plasmonic horn nanoantennas

    Science.gov (United States)

    Afridi, Adeel; Kocabaş, Şükrü Ekin

    2016-10-01

    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna.

  15. Beam steering and impedance matching of plasmonic horn nanoantennas

    CERN Document Server

    Afridi, Adeel

    2016-01-01

    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna.

  16. High speed, high power one-dimensional beam steering from a 6-element optical phased array.

    Science.gov (United States)

    Huang, W Ronny; Montoya, Juan; Kansky, Jan E; Redmond, Shawn M; Turner, George W; Sanchez-Rubio, Antonio

    2012-07-30

    Beam steering at high speed and high power is demonstrated from a 6-element optical phased array using coherent beam combining (CBC) techniques. The steering speed, defined as the inverse of the time to required to sweep the beam across the steering range, is 40 MHz and the total power is 396 mW. The measured central lobe FWHM width is 565 μrad. High on-axis intensity is maintained periodically by phase-locking the array via a stochastic-parallel-gradient-descent (SPGD) algorithm. A master-oscillator-power-amplifier (MOPA) configuration is used where the amplifier array elements are semiconductor slab-coupled-optical-waveguide-amplifiers (SCOWAs). The beam steering is achieved by LiNbO(3) phase modulators; the phase-locking occurs by current adjustment of the SCOWAs. The system can be readily scaled to GHz steering speed and multiwatt-class output.

  17. Ultra-thin anisotropic metasurface for polarized beam splitting and reflected beam steering applications

    Science.gov (United States)

    Guo, Wenlong; Wang, Guangming; Li, Tangjing; Li, Haipeng; Zhuang, Yaqiang; Hou, Haisheng

    2016-10-01

    In this paper, we propose a polarization beam splitter utilizing an ultra-thin anisotropic metasurface. The proposed anisotropic element is composed of triple-layered rectangular patches spaced with double-layered dielectric isolators. By tailoring the metallic patches, the cell is capable of transmitting x-polarized waves efficiently and reflecting y-polarized beams with almost 100% efficiency at 15 GHz. In addition to this, the reflected phases can be modulated by adjusting the size of the element, which contributes to beam steering in reflection mode. By assigning gradient phases on the metasurface, the constructed sample has the ability to refract x-polarized waves normally and reflect y-polarized beams anomalously. For verification, a sample with a size of 240 × 240 mm2 is fabricated and measured. Consistent numerical and experimental results have both validated the efficiently anomalous reflection for y-polarized waves and normal refraction for x-polarized beams operating from 14.6-15.4 GHz. Furthermore, the proposed sample has a thickness of 0.1λ at 15 GHz, which provides a promising approach for steering and splitting beams in a compact size.

  18. Steering, Splitting and Cloning of Optical Beam in a Coherently Driven Raman Gain System

    OpenAIRE

    Verma, Onkar N.; Dey, Tarak N.

    2014-01-01

    We propose an all-optical anti-waveguide mechanism for steering, splitting, and cloning of an optical beam beyond the diffraction-limit. We use a spatially inhomogeneous pump beam to create an anti-waveguide structure in a Doppler broadened N -type four-level Raman gain medium for a co-propagating weak probe beam. We show that a transverse modulated index of refraction and gain due to the spatially dependent pump beam hold the keys to steering, splitting and cloning of an optical beam. We hav...

  19. Coherence delay augmented laser beam homogenizer

    Science.gov (United States)

    Rasmussen, P.; Bernhardt, A.

    1993-06-29

    The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

  20. Two dimensional thermo-optic beam steering using a silicon photonic optical phased array

    Science.gov (United States)

    Mahon, Rita; Preussner, Marcel W.; Rabinovich, William S.; Goetz, Peter G.; Kozak, Dmitry A.; Ferraro, Mike S.; Murphy, James L.

    2016-03-01

    Components for free space optical communication terminals such as lasers, amplifiers, and receivers have all seen substantial reduction in both size and power consumption over the past several decades. However, pointing systems, such as fast steering mirrors and gimbals, have remained large, slow and power-hungry. Optical phased arrays provide a possible solution for non-mechanical beam steering devices that can be compact and lower in power. Silicon photonics is a promising technology for phased arrays because it has the potential to scale to many elements and may be compatible with CMOS technology thereby enabling batch fabrication. For most free space optical communication applications, two-dimensional beam steering is needed. To date, silicon photonic phased arrays have achieved two-dimensional steering by combining thermo-optic steering, in-plane, with wavelength tuning by means of an output grating to give angular tuning, out-of-plane. While this architecture might work for certain static communication links, it would be difficult to implement for moving platforms. Other approaches have required N2 controls for an NxN element phased array, which leads to complexity. Hence, in this work we demonstrate steering using the thermo-optic effect for both dimensions with a simplified steering mechanism requiring only two control signals, one for each steering dimension.

  1. Wearable Fabric Reconfigurable Beam-Steering Antenna for On/Off-Body Communication System

    Directory of Open Access Journals (Sweden)

    Seonghun Kang

    2015-01-01

    Full Text Available This paper presents a comparison of on-body performances between omnidirectional (loop antenna and reconfigurable beam-steering antennas. Both omnidirectional and reconfigurable antennas were manufactured on the same fabric substrate and operated at the frequency band of the WLAN 802.11a (5.725–5.85 GHz. The reconfigurable antenna was designed to steer the beam directions. In order to implement the beam-steering capability, the antenna used two PIN diodes. The maximum beam directions of three states (states 0, 1, and 2 were steerable in the YZ-plane (h=2°, 28°, and 326°, resp.. The measured peak gains were 5.9–6.6 dBi and the overall half power beam width (HPBW was 102°. The measured results of total radiated power (TRP and total isotropic sensitivity (TIS indicated that the communication efficiency of the reconfigurable beam steering antenna was better than that of the loop antenna. When the input power was 0.04 W (16 dBm, the simulated specific absorption rate (SAR values of the reconfigurable beam steering antenna on the body were less than 0.979 W/kg (1 g tissue in all states, satisfying the SAR criteria of the US.

  2. A new generation of IC based beam steering devices for free-space optical communication

    Science.gov (United States)

    Bedi, Vijit

    Free Space Optical (FSO) communication has tremendously advanced within the last decade to meet the ever increasing demand for higher communication bandwidth. Advancement in laser technology since its invention in the 1960's [1] attracted them to be the dominant source in FSO communication modules. The future of FSO systems lay in implementing semiconductor lasers due to their small size, power efficiency and mass fabrication abilities. In the near future, these systems are very likely to be used in space and ground based applications and revolutionary beam steering technologies will be required for distant communications in free-space. The highly directional characteristic inherent to a laser beam challenges and calls for new beam pointing and steering technologies for such type of communication. In this dissertation, research is done on a novel FSO communication device based on semiconductor lasers for high bandwidth communication. The "Fly eye transceiver" is an extremely wide steering bandwidth, completely non-mechanical FSO laser communication device primarily designed to replace traditional mechanical beam steering optical systems. This non-mechanical FSO device possesses a full spherical steering range and a very high tracking bandwidth. Inspired by the evolutionary model of a fly's eye, the full spherical steering range is assured by electronically controlled switching of its sub-eyes. Non mechanical technologies used in the past for beam steering such as acousto-optic Bragg cells, liquid crystal arrays or piezoelectric elements offer the wide steering bandwidth and fast response time, but are limited in their angular steering range. Mechanical gimbals offer a much greater steering range but face a much slower response time or steering bandwidth problem and often require intelligent adaptive controls with bulky driver amplifiers to feed their actuators. As a solution to feed both the fast and full spherical steering, the Fly-eye transceiver is studied as

  3. Design and Performance Evaluation of Optical Ethernet Switching Architecture with Liquid Crystal on Silicon-Based Beam-Steering Technology

    Science.gov (United States)

    Cheng, Yuh-Jiuh; Chou, H.-H.; Shiau, Yhi; Cheng, Shu-Ying

    2016-07-01

    A non-blocking optical Ethernet switching architecture with liquid crystal on a silicon-based beam-steering switch and optical output buffer strategies are proposed. For preserving service packet sequencing and fairness of routing sequence, priority and round-robin algorithms are adopted at the optical output buffer in this research. Four methods were used to implement tunable fiber delay modules for the optical output buffers to handle Ethernet packets with variable bit-rates. The results reported are based on the simulations performed to evaluate the proposed switching architecture with traffic analysis under a traffic model captured from a real-core network.

  4. Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas.

    Science.gov (United States)

    Liu, Kaipeng; Guo, Yinghui; Pu, Mingbo; Ma, Xiaoliang; Li, Xiong; Luo, Xiangang

    2017-01-30

    Despite a plethora of applications ranging from wireless communications to sensing and spectroscopy, the current terahertz beam steering technologies suffer from tremendous insert loss, stringent control of electric bias, limited scanning angle, relatively complicated configuration and narrow operation bandwidth, preventing further practical application. We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas. By adjusting the geometric dimension of the gap plasmon geodesic antennas, all gap plasmon modes add coherently along a peculiar direction that depends on the geodesic mean surface. Consequently, high directive beams are generated through the antenna, whose direction could be changed within a wide-angle range spanning ±45° by lateral motion of the feed. Furthermore, an assembled antenna structure consisting of four-element geodesic antennas array is proposed for full 360° beam steering, which can operate in a broadband range from 0.8 THz to 1.2 THz.

  5. Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas

    Science.gov (United States)

    Liu, Kaipeng; Guo, Yinghui; Pu, Mingbo; Ma, Xiaoliang; Li, Xiong; Luo, Xiangang

    2017-01-01

    Despite a plethora of applications ranging from wireless communications to sensing and spectroscopy, the current terahertz beam steering technologies suffer from tremendous insert loss, stringent control of electric bias, limited scanning angle, relatively complicated configuration and narrow operation bandwidth, preventing further practical application. We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas. By adjusting the geometric dimension of the gap plasmon geodesic antennas, all gap plasmon modes add coherently along a peculiar direction that depends on the geodesic mean surface. Consequently, high directive beams are generated through the antenna, whose direction could be changed within a wide-angle range spanning ±45° by lateral motion of the feed. Furthermore, an assembled antenna structure consisting of four-element geodesic antennas array is proposed for full 360° beam steering, which can operate in a broadband range from 0.8 THz to 1.2 THz.

  6. Highly integrated optical phased arrays: photonic integrated circuits for optical beam shaping and beam steering

    Directory of Open Access Journals (Sweden)

    Heck Martijn J.R.

    2017-01-01

    Full Text Available Technologies for efficient generation and fast scanning of narrow free-space laser beams find major applications in three-dimensional (3D imaging and mapping, like Lidar for remote sensing and navigation, and secure free-space optical communications. The ultimate goal for such a system is to reduce its size, weight, and power consumption, so that it can be mounted on, e.g. drones and autonomous cars. Moreover, beam scanning should ideally be done at video frame rates, something that is beyond the capabilities of current opto-mechanical systems. Photonic integrated circuit (PIC technology holds the promise of achieving low-cost, compact, robust and energy-efficient complex optical systems. PICs integrate, for example, lasers, modulators, detectors, and filters on a single piece of semiconductor, typically silicon or indium phosphide, much like electronic integrated circuits. This technology is maturing fast, driven by high-bandwidth communications applications, and mature fabrication facilities. State-of-the-art commercial PICs integrate hundreds of elements, and the integration of thousands of elements has been shown in the laboratory. Over the last few years, there has been a considerable research effort to integrate beam steering systems on a PIC, and various beam steering demonstrators based on optical phased arrays have been realized. Arrays of up to thousands of coherent emitters, including their phase and amplitude control, have been integrated, and various applications have been explored. In this review paper, I will present an overview of the state of the art of this technology and its opportunities, illustrated by recent breakthroughs.

  7. Highly integrated optical phased arrays: photonic integrated circuits for optical beam shaping and beam steering

    Science.gov (United States)

    Heck, Martijn J. R.

    2017-01-01

    Technologies for efficient generation and fast scanning of narrow free-space laser beams find major applications in three-dimensional (3D) imaging and mapping, like Lidar for remote sensing and navigation, and secure free-space optical communications. The ultimate goal for such a system is to reduce its size, weight, and power consumption, so that it can be mounted on, e.g. drones and autonomous cars. Moreover, beam scanning should ideally be done at video frame rates, something that is beyond the capabilities of current opto-mechanical systems. Photonic integrated circuit (PIC) technology holds the promise of achieving low-cost, compact, robust and energy-efficient complex optical systems. PICs integrate, for example, lasers, modulators, detectors, and filters on a single piece of semiconductor, typically silicon or indium phosphide, much like electronic integrated circuits. This technology is maturing fast, driven by high-bandwidth communications applications, and mature fabrication facilities. State-of-the-art commercial PICs integrate hundreds of elements, and the integration of thousands of elements has been shown in the laboratory. Over the last few years, there has been a considerable research effort to integrate beam steering systems on a PIC, and various beam steering demonstrators based on optical phased arrays have been realized. Arrays of up to thousands of coherent emitters, including their phase and amplitude control, have been integrated, and various applications have been explored. In this review paper, I will present an overview of the state of the art of this technology and its opportunities, illustrated by recent breakthroughs.

  8. A prototype of a beam steering assistant tool for accelerator operations

    Energy Technology Data Exchange (ETDEWEB)

    M. Bickley; P. Chevtsov

    2006-10-24

    The CEBAF accelerator provides nuclear physics experiments at Jefferson Lab with high quality electron beams. Three experimental end stations can simultaneously receive the beams with different energies and intensities. For each operational mode, the accelerator setup procedures are complicated and require very careful checking of beam spot sizes and positions on multiple beam viewers. To simplify these procedures and make them reproducible, a beam steering assistant GUI tool has been created. The tool is implemented as a multi-window control screen. The screen has an interactive graphical object window, which is an overlay on top of a digitized live video image from a beam viewer. It allows a user to easily create and edit any graphical objects consisting of text, ellipses, and lines, right above the live beam viewer image and then save them in a file that is called a beam steering template. The template can show, for example, the area within which the beam must always be on the viewer. Later, this template can be loaded in the interactive graphical object window to help accelerator operators steer the beam to the specified area on the viewer.

  9. Practical realization of dual S arm antenna for beam steering applications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A dual S shaped micro strip antenna with a realistic feed is proposed for generation of tilted beam radiation pattern pertaining for beam steering applications. To achieve this, four feeding points are located at a distance of 5.6 mm from the antenna centre. These feeding points when excited one by one generate four tilted beams in four different space quadrants, thus yielding a beam steerable antenna. Importantly, since the proposed antenna is symmetrical in the structure, all the four tilted beams have the same radiation pattern characteristics. A further enhancement of the antenna bandwidth is also achieved using 100-μm capacitive coupling between the feed and the antenna strip.

  10. Demonstration of beam steering via dipole-coupled plasmonic spiral antenna.

    Science.gov (United States)

    Rui, Guanghao; Abeysinghe, Don C; Nelson, Robert L; Zhan, Qiwen

    2013-01-01

    Optical antennas have been utilized to tailor the emission properties of nanoscale emitters in terms of the intensity, directivity and polarization. In this letter, we further explore the capability of beam steering via the use a spiral plasmonic structure as a transmitting antenna. According to both numerical simulation and experimental observations, the beaming direction can be steered through introducing a displacement of the feeding point to the spiral antenna from the geometrical center. For a 3-turn Archimedes' spiral antenna, experimental results show that steering angles of 3° and 7° are obtainable when the excitation location is transversally shifted from the center by a displacement of 200 nm and 500 nm, respectively. Furthermore, the emitted photons carry spin angular momentum determined by the chirality of the spiral optical antenna. A steerable nanoscale spin photon source may find important applications in single molecule sensing, quantum optical information processing and integrated photonic circuits.

  11. Characterizing the beam steering and distortion of Gaussian and Bessel beams focused in tissues with microscopic heterogeneities.

    Science.gov (United States)

    Chen, Ye; Liu, Jonathan T C

    2015-04-01

    Bessel beams have recently been investigated as a means of improving deep-tissue microscopy in highly scattering and heterogeneous media. It has been suggested that the long depth-of-field and self-reconstructing property of a Bessel beam enables an increased penetration depth of the focused beam in tissues compared to a conventional Gaussian beam. However, a study is needed to better quantify the magnitude of the beam steering as well as the distortion of focused Gaussian and Bessel beams in tissues with microscopic heterogeneities. Here, we have developed an imaging method and quantitative metrics to evaluate the motion and distortion of low-numerical-aperture (NA) Gaussian and Bessel beams focused in water, heterogeneous phantoms, and fresh mouse esophagus tissues. Our results indicate that low-NA Bessel beams exhibit reduced beam-steering artifacts and distortions compared to Gaussian beams, and are therefore potentially useful for microscopy applications in which pointing accuracy and beam quality are critical, such as dual-axis confocal (DAC) microscopy.

  12. Fabrication of solar beam steering electrowetting devices—present status and future prospects

    Science.gov (United States)

    Khan, I.; Castelletto, S.; Rosengarten, G.

    2017-10-01

    Many different technologies are used to track the movement of the sun to both enable concentration of its energy and maximize the yearly energy capture. Their present main limitations are the cost, size, visual impact and wind loading, particularly for applications involving mounting to a building. A parabolic concentrator, for example, along with its steering equipment is heavy and bulky, and is not suitable for rooftop applications. Instead, thin and flat solar concentration devices are required for hassle-free rooftop applications. The use of electrowetting-controlled liquid lenses has emerged as a novel approach for solar tracking and concentration. By steering sunlight using thin electrowetting cell arrays, bulky mechanical equipment is not required. The basic concept of this technology is to change the shape of a liquid interface that is formed by two immiscible fluids of different refractive indices, by simply applying an electric field. An important challenge in electrowetting beam steering devices is the optimization of the design and fabrication process for each of their main constituent components, to maximize optical efficiency. In this paper, we report on the state-of-the-art fabrication methods for electrowetting devices for solar beam steering. We have reviewed the present status of different components types and related fabrication methods, and how they affect the efficiency and performance of such devices. The work identifies future prospects in using electrowetting beam steering devices for solar energy applications. This paper will help researchers and developers in the field to determine the components and fabrication process that affect the development of efficient beam steering electrowetting devices.

  13. Beam Steering at Higher Photonic Bands and Design of a Directional Cloak Formed by Photonic Crystals

    Directory of Open Access Journals (Sweden)

    Venkatachalam Subramanian

    2013-02-01

    Full Text Available Beam steering due to anomalous dispersion at higher photonic bands in dielectric photonic crystal is reported in this work. Based on this concept, directional cloak is designed that conceals a larger dimensional scattering object against the normal incident, linearly polarizedelectromagnetic waves.

  14. Method of electronic beam steering for circular switched parasitic dipole arrays

    CSIR Research Space (South Africa)

    Mofolo, M

    2010-09-01

    Full Text Available This paper presents a method of electronic beam steering for a smart antenna system based on a switched parasitic array. The antenna system is made up of circular array of half wave dipoles, with four parasitic elements positioned equidistantly...

  15. One mirror beam steering: determination of steering mirror parameters from image pointing direction

    Science.gov (United States)

    Andersen, Torben B.; Granger, Zachary A.

    2016-09-01

    Mathematical models are used to establish the exact path of a beam reflected by a plane mirror in terms of the mirror geometry descriptors. In particular, the mirror geometry descriptors (tilt angles) are determined as functions of the beam path in image space. This is also useful for determining scan patterns when the mirror is used as a scanning device. These formulations are readily adaptable to commercially available ray tracing programs.

  16. Tunable Reflectarray Cell for Wide Angle Beam-Steering Radar Applications

    Directory of Open Access Journals (Sweden)

    F. Venneri

    2013-01-01

    Full Text Available An electronically tunable reflectarray element is proposed in this work to design beam-steering antennas useful for radar applications. A reduced size reflectarray unit cell is properly synthesized in order to extend the antenna beam scanning capabilities within a wider angular region. The radiating structure is accurately optimized to provide a full phase tuning range by adopting a single varactor load as phase shifter element. A 0.46λ-reflectarray cell is designed at the frequency of 11.5 GHz, obtaining a phase agility of about 330°. The cell is successfully adopted for the design of a 21 × 21 reconfigurable reflectarray. The antenna is numerically tested for different configurations of the varactors capacitance values, and good beam-steering performances are demonstrated within a wide angular range.

  17. Beam steering effects in turbulent high pressure flames

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The propagation of a laser beam through a flame is influenced by variations of the optical density. Especially in turbulent high pressure flames this may seriously limit the use of laser diagnostic methods. (author) 1 fig., 2 refs.

  18. GMTIFS: the adaptive optics beam steering mirror for the GMT integral-field spectrograph

    Science.gov (United States)

    Davies, J.; Bloxham, G.; Boz, R.; Bundy, D.; Espeland, B.; Fordham, B.; Hart, J.; Herrald, N.; Nielsen, J.; Sharp, R.; Vaccarella, A.; Vest, C.; Young, P. J.

    2016-07-01

    To achieve the high adaptive optics sky coverage necessary to allow the GMT Integral-Field Spectrograph (GMTIFS) to access key scientific targets, the on-instrument adaptive-optics wavefront-sensing (OIWFS) system must patrol the full 180 arcsecond diameter guide field passed to the instrument. The OIWFS uses a diffraction limited guide star as the fundamental pointing reference for the instrument. During an observation the offset between the science target and the guide star will change due to sources such as flexure, differential refraction and non-sidereal tracking rates. GMTIFS uses a beam steering mirror to set the initial offset between science target and guide star and also to correct for changes in offset. In order to reduce image motion from beam steering errors to those comparable to the AO system in the most stringent case, the beam steering mirror is set a requirement of less than 1 milliarcsecond RMS. This corresponds to a dynamic range for both actuators and sensors of better than 1/180,000. The GMTIFS beam steering mirror uses piezo-walk actuators and a combination of eddy current sensors and interferometric sensors to achieve this dynamic range and control. While the sensors are rated for cryogenic operation, the actuators are not. We report on the results of prototype testing of single actuators, with the sensors, on the bench and in a cryogenic environment. Specific failures of the system are explained and suspected reasons for them. A modified test jig is used to investigate the option of heating the actuator and we report the improved results. In addition to individual component testing, we built and tested a complete beam steering mirror assembly. Testing was conducted with a point source microscope, however controlling environmental conditions to less than 1 micron was challenging. The assembly testing investigated acquisition accuracy and if there was any un-sensed hysteresis in the system. Finally we present the revised beam steering mirror

  19. Initial investigation using statistical process control for quality control of accelerator beam steering

    Directory of Open Access Journals (Sweden)

    Able Charles M

    2011-12-01

    Full Text Available Abstract Background This study seeks to increase clinical operational efficiency and accelerator beam consistency by retrospectively investigating the application of statistical process control (SPC to linear accelerator beam steering parameters to determine the utility of such a methodology in detecting changes prior to equipment failure (interlocks actuated. Methods Steering coil currents (SCC for the transverse and radial planes are set such that a reproducibly useful photon or electron beam is available. SCC are sampled and stored in the control console computer each day during the morning warm-up. The transverse and radial - positioning and angle SCC for photon beam energies were evaluated using average and range (Xbar-R process control charts (PCC. The weekly average and range values (subgroup n = 5 for each steering coil were used to develop the PCC. SCC from September 2009 (annual calibration until two weeks following a beam steering failure in June 2010 were evaluated. PCC limits were calculated using the first twenty subgroups. Appropriate action limits were developed using conventional SPC guidelines. Results PCC high-alarm action limit was set at 6 standard deviations from the mean. A value exceeding this limit would require beam scanning and evaluation by the physicist and engineer. Two low alarms were used to indicate negative trends. Alarms received following establishment of limits (week 20 are indicative of a non-random cause for deviation (Xbar chart and/or an uncontrolled process (R chart. Transverse angle SCC for 6 MV and 15 MV indicated a high-alarm 90 and 108 days prior to equipment failure respectively. A downward trend in this parameter continued, with high-alarm, until failure. Transverse position and radial angle SCC for 6 and 15 MV indicated low-alarms starting as early as 124 and 116 days prior to failure, respectively. Conclusion Radiotherapy clinical efficiency and accelerator beam consistency may be improved by

  20. Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas

    Science.gov (United States)

    Liu, Kaipeng; Guo, Yinghui; Pu, Mingbo; Ma, Xiaoliang; Li, Xiong; Luo, Xiangang

    2017-01-01

    Despite a plethora of applications ranging from wireless communications to sensing and spectroscopy, the current terahertz beam steering technologies suffer from tremendous insert loss, stringent control of electric bias, limited scanning angle, relatively complicated configuration and narrow operation bandwidth, preventing further practical application. We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas. By adjusting the geometric dimension of the gap plasmon geodesic antennas, all gap plasmon modes add coherently along a peculiar direction that depends on the geodesic mean surface. Consequently, high directive beams are generated through the antenna, whose direction could be changed within a wide-angle range spanning ±45° by lateral motion of the feed. Furthermore, an assembled antenna structure consisting of four-element geodesic antennas array is proposed for full 360° beam steering, which can operate in a broadband range from 0.8 THz to 1.2 THz. PMID:28134324

  1. Beam steering and deflecting device using step-based micro-blazed grating

    Science.gov (United States)

    Yang, Junbo; Su, Xianyu; Xu, Ping; Gu, Zheng

    2008-08-01

    The rapidly evolving demands of optical communications and optical switching systems have created a new market for high capacity all-optical beam steering and deflecting techniques. One technology potentially capable of realizing such systems uses the multistep micro-blazed grating optical beam deflectors based on binary and multiple-phase modulation methods. The micro-optical element has been fabricated by introducing very large scale integration (VLSI), stepping photolithography and reactive ion etching (RIE), which can realize beam steering, deflecting, splitting, and switching in free space, and its diffraction properties are determined by the blazed-grating parameters, such as the number of steps, grating depth, grating period, as well as blazed profile. The theoretical analysis and primarily experimental result show that this phase-type element has the advantages of high diffractive efficiency, low cross talk, small feature size, and high reliability due to nonmechanical beam steering without any moving parts. Hence it is ideally suited to applications in optical communication and optical interconnection network.

  2. Helicopter downwash measured by continuous-wave Doppler lidars with agile beam steering

    DEFF Research Database (Denmark)

    Sjöholm, Mikael; Angelou, Nikolas; Hansen, Per

    2012-01-01

    A ground-based remote sensing short-range WindScanner with agile beam steering based on a modified ZephIR continuous-wave wind lidar (LIght Detection And Ranging) and a double prism arrangement has recently been developed at the Department of Wind Energy at the DTU Risø campus. The WindScanner me......A ground-based remote sensing short-range WindScanner with agile beam steering based on a modified ZephIR continuous-wave wind lidar (LIght Detection And Ranging) and a double prism arrangement has recently been developed at the Department of Wind Energy at the DTU Risø campus. The Wind...

  3. Design and development of an electrically-controlled beam steering mirror for microwave tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tayebi, A., E-mail: tayebiam@msu.edu [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Tang, J.; Paladhi, P. Roy; Udpa, L.; Udpa, S. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI-48824, USA and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2015-03-31

    Microwave tomography has gained significant attention due to its reliability and unhazardous nature in the fields of NDE and medical industry. A new microwave tomography system is presented in this paper, which significantly reduces the design and operational complexities of traditional microwave imaging systems. The major component of the proposed system is a reconfigurable reflectarray antenna which is used for beam steering in order to generate projections from multiple angles. The design, modeling and fabrication of the building block of the antenna, a tunable unit cell, are discussed in this paper. The unit cell is capable of dynamically altering the phase of the reflected field which results in beam steering ability of the reflectarray antenna. A tomographically reconstructed image of a dielectric sample using this new microwave tomography system is presented in this work.

  4. 2D Traveling Wave Array Employing a Trapezoidal Dielectric Wedge for Beam Steering

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranada, Felix A.

    2014-01-01

    This presentation addresses the progress made so far in the development of an antenna array with reconfigurable transmission line feeds connecting each element in series. In particular, 2D traveling wave array employing trapezoidal Dielectric Wedge for Beam Steering will be discussed. The presentation includes current status of the effort and suggested future work. The work is being done as part of the NASA Office of the Chief Technologist's Space Technology Research Fellowship (NSTRF).

  5. A microwave tomography system using a tunable mirror for beam steering

    Energy Technology Data Exchange (ETDEWEB)

    Tayebi, A. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824 (United States); Non-Destructive Evaluation Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physic (United States); Tang, J. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824 (United States); Paladhi, P. Roy; Udpa, L.; Udpa, S. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824 (United States); Non-Destructive Evaluation Laboratory, Michigan State University, East Lansing, MI 48824 (United States)

    2014-02-18

    Microwave tomography is a fast-growing technique in the fields of NDE and medical industry. This paper presents a new microwave tomography system which reduces the complexities of conventional microwave imaging systems by utilizing a reconfigurable mirror, a tunable reflectarray antenna. In order to build a tunable reflectarray with beam steering capabilities, the unit cell characteristics should dynamically alter. Modelling and experimental results of a single unit cell are presented in this work.

  6. A Time Modulated Printed Dipole Antenna Array for Beam Steering Application

    Directory of Open Access Journals (Sweden)

    Ruchi Gahley

    2017-01-01

    Full Text Available This paper presents time modulated beam steered antenna array without phase shifters. The beam steering is analyzed considering a two-element time modulated antenna array (TMAA of printed dipoles with microstrip via-hole balun. The proposed array resonates at the Industrial, Scientific, and Medical (ISM radio bands, 2.45 GHz and 5.8 GHz, and offers wide bandwidth inherited due to modified structure of ground plane. Array elements are excited by complex exponential excitation signal through broadband power divider and radio frequency (RF switches to achieve amplitude and phase variation without phase shifters. Differential Evolution algorithm is used to modify the time sequences of the RF switches connected to the antennas to generate radiation pattern with optimum dynamic efficiency by suppressing sideband radiations. Also switch-on time instant of RF switch connected to the subsequent element is modulated to steer the beam towards different directions. The proposed prototype is fabricated followed by parametric optimization. The fabrication results agree significantly well with simulated results.

  7. Electrostatic steering and beamlet aiming in large neutral beam injectors

    Science.gov (United States)

    Veltri, P.; Cavenago, M.; Chitarin, G.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P.

    2015-04-01

    Neutral beam injection is the main method for plasma heating in magnetic confinement fusion devices. In high energy injector (E>100 keV/amu), neutrals are obtained with reasonable efficiency by conversion of negative ions (H- or D-) via electron detachment reactions. In the case of ITER injectors, which shall operate at 1 MeV, a total ion current of ˜ 40 A is required to satisfy the heating power demand. Gridded electrodes are therefore used in the accelerator, so that 1280 negative ion beamlets are accelerated together. A carefully designed aiming system is required to control the beamlet trajectories, and to deliver their power on a focal point located several meters away from the beam source. In nowadays injectors, the aiming is typically obtained by aperture offset technique or by grid shaping. This paper discuss an alternative concept of beamlets aiming, based on an electrostatic "steerer" to be placed at the end of the accelerator. A feasibility study of this component is also presented, and its main advantages and drawbacks with respect to other methods are discussed.

  8. Electrostatic steering and beamlet aiming in large neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Veltri, P., E-mail: pierluigi.veltri@igi.cnr.it; Chitarin, G.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4 - 35127 Padova (Italy); Cavenago, M. [INFN-LNL, viale dell' Università n. 2, 35020 Legnaro (Italy)

    2015-04-08

    Neutral beam injection is the main method for plasma heating in magnetic confinement fusion devices. In high energy injector (E>100 keV/amu), neutrals are obtained with reasonable efficiency by conversion of negative ions (H- or D-) via electron detachment reactions. In the case of ITER injectors, which shall operate at 1 MeV, a total ion current of ∼ 40 A is required to satisfy the heating power demand. Gridded electrodes are therefore used in the accelerator, so that 1280 negative ion beamlets are accelerated together. A carefully designed aiming system is required to control the beamlet trajectories, and to deliver their power on a focal point located several meters away from the beam source. In nowadays injectors, the aiming is typically obtained by aperture offset technique or by grid shaping. This paper discuss an alternative concept of beamlets aiming, based on an electrostatic ”steerer” to be placed at the end of the accelerator. A feasibility study of this component is also presented, and its main advantages and drawbacks with respect to other methods are discussed.

  9. Wavelength agile nonmechanical laser beam steering from Fresnel zone plates imprinted on a liquid crystal spatial light modulator

    Science.gov (United States)

    Lindle, James R.; Watnik, Abbie T.; Cassella, Vincent A.

    2016-09-01

    Multibeam, multicolor, large-angle beam-steering is demonstrated in the visible spectral region by imprinting Fresnel zone plates (FZP) on a liquid crystal spatial light modulator. Spectral dispersion, both diffractive and refractive, is observed but does not prevent the use of this technology for beam steering applications. The experimental results show that while diffractive dispersion dominates over refractive dispersion, wavelength-specific FZPs can be rendered to direct those beams on target, either simultaneously or consecutively. Only a slight correction in the FZP positon is necessary to compensate for refractive dispersion. The position, intensity, and wavelength of each beam can be controlled independently.

  10. High-gradient microelectromechanical system quadrupole electromagnets for particle beam focusing and steering

    Directory of Open Access Journals (Sweden)

    Jere Harrison

    2015-02-01

    Full Text Available Recent advancements in microelectromechanical system (MEMS fabrication techniques have enabled the batch-fabrication of quadrupole MEMS electromagnets producing 100 mT-scale field across sub-mm gaps with the potential for transformational advances in the field of compact high performance charged particle focusing and steering optics. The footprint of these in-vacuum focusing and steering optics can be as small as 3  mm×3  mm×0.5  mm. The low electromagnet impedance (58  mΩ, 32 nH per pole facilitates power-efficient operation and continuous or low duty cycle operation, and the individually controlled electromagnets allow combined dipole-quadrupole fields. Here we report on an experiment where these miniature devices have been used to focus and steer a 34 keV electron beam from a DC photogun, demonstrating the first application of magnetic MEMS to particle beam focusing.

  11. MAcro-Electro-Mechanical Systems (MÆMS) based concept for microwave beam steering in reflectarray antennas

    Science.gov (United States)

    Momeni Hasan Abadi, Seyed Mohamad Amin; Booske, John H.; Behdad, Nader

    2016-08-01

    We present a new approach to perform beam steering in reflecting type apertures such as reflectarray antennas. The proposed technique exploits macro-scale mechanical movements of parts of the structure to achieve two-dimensional microwave beam steering without using any solid-state devices or phase shifters integrated within the aperture of the antenna. The principles of operation of this microwave beam steering technique are demonstrated in an aperture occupied by ground-plane-backed, sub-wavelength capacitive patches with identical dimensions. We demonstrate that by tilting the ground plane underneath the entire patch array layer, a phase shift gradient can be created over the aperture of the reflectarray that determines the direction of the radiated beam. Changing the direction and slope of this phase shift gradient on the aperture allows for performing beam steering in two dimensions using only one control parameter (i.e., tilt vector of the ground plane). A proof-of-concept prototype of the structure operating at X-band is designed, fabricated, and experimentally characterized. Experiments demonstrate that small mechanical movements of the ground plane (in the order of 0.05λ0) can be used to steer the beam direction in the ±10° in two dimensions. It is also demonstrated that this beam scanning range can be greatly enhanced to ±30° by applying this concept to the same structure when its ground plane is segmented.

  12. Utilization of an ultrasound beam steering angle for measurements of tissue displacement vector and lateral displacement

    Directory of Open Access Journals (Sweden)

    Chikayoshi Sumi

    2010-09-01

    Full Text Available Chikayoshi SumiDepartment of Information and Communication Sciences, Faculty of Science and Technology, Sophia University, Tokyo, JapanAbstract: A number of ultrasonic displacement/velocity measurement methods have been extensively developed for measurements of blood flow, tissue motion, and strain. Lateral modulation (LM methods have also been reported using steered, crossed beams, and these methods permit measurements of displacement vectors. In this report, a new beam steering method for the transmission and reception of ultrasound is proposed, which can enable measurements of lateral displacements and of arbitrary displacement vectors with a very high degree of accuracy. Because this beam steering method uses only a steering angle, this method is referred to as ASTA. With ASTA, the number of available methods to obtain a displacement vector measurement is limited to previously developed block-matching methods, such as the multidimensional cross-spectrum phase gradient method, and the multidimensional autocorrelation method (MAM and the multidimensional Doppler method (MDM using a block-matching method (the methods using block matching are referred to as MAMb and MDMb, respectively. Being dependent on the measurement method, only a lateral displacement measurement can be made even if the methods are multidimensional, ie, previously developed MAM and MDM using a moving average and a mirror setting of the obtained steered beams, and one-dimensional (1D, such as an autocorrelation method. Considerations of beamforming schemes using LM and ASTA show that the simple ASTA beamforming method increases capabilities for real-time measurements and requires a small physical aperture when compared with LM. For lateral displacement measurements (eg, blood flow in a carotid artery, a lateral coordinate must correspond to the direction of the target’s lateral motion, and the steering angle used is as large as possible to increase the measurement accuracy

  13. Two-axis Beam Steering Mirror Control system for Precision Pointing and Tracking Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ulander, Klaus [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2006-01-01

    Precision pointing and tracking of laser beams is critical in numerous military and industrial applications. This is particularly true for systems requiring atmospheric beam propagation. Such systems are plagued by environmental influences which cause the optical signal to break up and wander. Example applications include laser communications, precision targeting, active imaging, chemical remote sensing, and laser vibrometry. The goal of this project is to build a beam steering system using a two-axis mirror to maintain precise pointing control. Ultimately, position control to 0.08% accuracy (40 {micro}rad) with a bandwidth of 200 Hz is desired. The work described encompasses evaluation of the instrumentation system and the subsequent design and implementation of an analog electronic controller for a two-axis mirror used to steer the beam. The controller operates over a wide temperature range, through multiple mirror resonances, and is independent of specific mirrors. The design was built and successfully fielded in a Lawrence Livermore National Laboratory free-space optics experiment. All measurements and performance parameters are derived from measurements made on actual hardware that was built and field tested. In some cases, specific design details have been omitted that involve proprietary information pertaining to Lawrence Livermore National Laboratory patent positions and claims. These omissions in no way impact the general validity of the work or concepts presented in this thesis.

  14. Report for simultaneous, multiple independently steered beam study for Airborne Electronically Steerable Phased Array (AESPA) program

    Science.gov (United States)

    1978-01-01

    Design concepts of an array for the formation of multiple, simultaneous, independently pointed beams for satellite communication links were investigated through tradeoffs of various approaches which were conceived as possible solutions to the problem. After the preferred approach was selected, a more detailed design was configured and is presented as a candidate system that should be given further consideration for development leading to a preliminary design. This array uses an attenuator and a phase shifter with every element. The aperture excitation necessary to form the four beams is calculated and then placed across the array using these devices. Pattern analysis was performed for two beam and four beam cases with numerous patterns being presented. Parameter evaluation shown includes pointing accuracy and beam shape, sidelobe characteristics, gain control, and beam normalization. It was demonstrated that a 4 bit phase shifter and a 6 bit, 30 dB attenuator were sufficient to achieve adequate pattern performances. The phase amplitude steered multibeam array offers the flexibility of 1 to 4 beams with an increase in gain of 6 dB if only one beam is selected.

  15. Controlling Beam Halo-Chaos via Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; WENG Jia-Qiang; ZHU Lun-Wu; LUO Xiao-Shu

    2004-01-01

    The study of controlling high-current proton beam halo-chaos has become a key concerned issue for many important applications. In this paper, time-delayed feedback control method is proposed for beam halo-chaos. Particle in cell simulation results show that the method is very effective and has some advantages for high-current beam experiments and engineering.

  16. A clock steering method: using a third-order type 3 DPLL equivalent to a Kalman filter with a delay

    Science.gov (United States)

    Wu, Yiwei; Gong, Hang; Zhu, Xiangwei; Ou, Gang

    2015-12-01

    In this paper we propose a new clock steering method, which uses a third-order type 3 digital phase locked loop (DPLL) which is equivalent to a Kalman filter with a delay. A general overview of the theoretical framework is described in detail including the transfer functions, the structure and control values, the specifications, and the approach to choosing a parameter. Simulations show that the performance of the time and frequency steering errors and the frequency stability are quite desirable. Comparing with traditional clock steering methods, it is easier to work with just one parameter. The DPLL method satisfies the requirements of generating a local representation of universal time coordinated and the system time of a global navigation satellite system.

  17. Integrated optical phased array based large angle beam steering system fabricated on silicon-on-insulator

    Science.gov (United States)

    Kwong, David N.; Zhang, Yang; Hosseini, Amir; Chen, Ray T.

    2011-01-01

    In this paper, we present a highly compact silicon nano-membrane based optical phased array fabricated using conventional CMOS processing on silicon-on-insulator that provides for over 10 degrees of beam steering in a silicon slab at λ=1.55μm using transverse-electrical polarized light. A low loss 1-to-12 multi-mode interference (MMI) optical beam splitter with high uniformity is used to provide inputs to the optical phased array. Using an unequally spaced waveguide array permits us to relax the half-wavelength spacing requirement for large angle beam steering, thereby avoiding the optical coupling between adjacent waveguides and reducing the side-lobe-level of the array radiation pattern. S-bend waveguides convert the equally spaced MMI output to the unequally spaced wave guide array, while passively equalizing the phases of each array element to compensate for the MMI output phase profile. Independently controllable thin film metal heaters are used to achieve phase shifting using the strong thermo-optic response of silicon. Heat-insulating air grooves minimize thermal crosstalk, while also achieving and low power consumption.

  18. Beam steering in superconducting quarter-wave resonators: An analytical approach

    Directory of Open Access Journals (Sweden)

    Alberto Facco

    2011-07-01

    Full Text Available Beam steering in superconducting quarter-wave resonators (QWRs, which is mainly caused by magnetic fields, has been pointed out in 2001 in an early work [A. Facco and V. Zviagintsev, in Proceedings of the Particle Accelerator Conference, Chicago, IL, 2001 (IEEE, New York, 2001, p. 1095], where an analytical formula describing it was proposed and the influence of cavity geometry was discussed. Since then, the importance of this effect was recognized and effective correction techniques have been found [P. N. Ostroumov and K. W. Shepard, Phys. Rev. ST Accel. Beams 4, 110101 (2001PRABFM1098-440210.1103/PhysRevSTAB.4.110101]. This phenomenon was further studied in the following years, mainly with numerical methods. In this paper we intend to go back to the original approach and, using well established approximations, derive a simple analytical expression for QWR steering which includes correction methods and reproduces the data starting from a few calculable geometrical constants which characterize every cavity. This expression, of the type of the Panofski equation, can be a useful tool in the design of superconducting quarter-wave resonators and in the definition of their limits of application with different beams.

  19. Evaluation of an optical beam-position-monitor system with closed-loop steering capabilities

    Science.gov (United States)

    Bissen, Mark; Rogers, Greg; Wood, William; Eisert, Dave; Kleman, K. J.; Winter, William; Höchst, Hartmut

    1994-08-01

    Imaging the synchrotron source profile onto the entrance slit of a monochromator provides a stable and reproducible energy calibration which is independent of the absolute position and drift of the electron beam. Potential electron-beam motions occurring during a fill result in a loss of flux through the beamline. We have implemented two independent beam position monitors which can be used as sensors to steer the vertical entrance mirror in order to maintain a maximum flux through a spherical grating varied line-spacing monochromator beamline. The system consists of a slotted plate photodiode which intercepts 2 mrad of synchrotron radiation next to the entrance mirror and a detector utilizing the photocurrents generated at the jaws of the entrance-slit assembly. Both monitors have a wide linear response range with a vertical position resolution of beam position monitors allows an easy check on the mechanical and thermal stability of the entrance optical system as well as on the reproducibility and long-term fluctuations of the electron-beam source during user shifts. We will discuss the performance of the optical beam-position-monitor system and its implementation as a sensor in a closed-loop feedback system to maintain maximum flux through the beamline.

  20. Digital Beam Steering Device Based on Decoupled Birefringent Prism Deflector and Polarization Rotator

    Science.gov (United States)

    Pishnyak, Oleg; Kreminska, Lyubov; Laventovich, Oleg D.; Pouch, John J.; Miranda, Felix A.; Winker, Bruce K.

    2004-01-01

    We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises a polarization rotator and a birefringent prism deflector. The birefringent prism deflects the beam by an angle that depends on polarization of the incident beam. The prism can be made of the uniaxial smectic A (SmA) liquid crystal (LC) or a solid crystal such as yttrium orthovanadate (YVO4). SmA prisms have high birefringence and can be constructed in a variety of shapes, including single prisms and prismatic blazed gratings of different angles and profiles. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by an electrically switched twisted nematic (TN) cell. A DBD composed of N rotator-deflector pairs steers the beam into 2(sup N) directions. As an example, we describe a four-stage DBD deflecting normally incident laser beam within the range of +/- 56 mrad with 8 mrad steps. Redirection of the beam is achieved by switching the TN cells.

  1. Diode laser lidar wind velocity sensor using a liquid-crystal retarder for non-mechanical beam-steering

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Iversen, Theis Faber Quist; Hu, Qi;

    2014-01-01

    We extend the functionality of a low-cost CW diode lasercoherent lidar from radial wind speed (scalar) sensing to wind velocity(vector) measurements. Both speed and horizontal direction of the wind at~80 m remote distance are derived from two successive radial speedestimates by alternately steering...... the lidar probe beam in two different lines-of-sight (LOS) with a 60° angular separation. Dual-LOS beam-steering isimplemented optically with no moving parts by means of a controllableliquid-crystal retarder (LCR). The LCR switches the polarization betweentwo orthogonal linear states of the lidar beam so...... steered fromone LOS to the other every half a second is experimentally demonstrated –resulting in 1 Hz rate estimates of wind velocity magnitude and direction atbetter than 0.1 m/s and 1° resolution, respectively...

  2. Monolithic beam steering in a mid-infrared, surface-emitting, photonic integrated circuit.

    Science.gov (United States)

    Slivken, Steven; Wu, Donghai; Razeghi, Manijeh

    2017-08-16

    The mid-infrared (2.5 infrared optical systems, however, mid-infrared component technology is still rather crude, with isolated components exhibiting limited functionality. In this manuscript, we make a significant leap forward in mid-infrared technology by developing a platform which can combine functions of multiple mid-infrared optical elements, including an integrated light source. In a single device, we demonstrate wide wavelength tuning (240 nm) and beam steering (17.9 degrees) in the mid-infrared with a significantly reduced beam divergence (down to 0.5 degrees). The architecture is also set up to be manufacturable and testable on a wafer scale, requiring no cleaved facets or special mirror coating to function.

  3. Synthesis of Steered Flat-top Beam Pattern Using Evolutionary Algorithm

    Directory of Open Access Journals (Sweden)

    D. Mandal

    2016-12-01

    Full Text Available In this paper a pattern synthesis method based on Evolutionary Algorithm is presented. A Flat-top beam pattern has been generated from a concentric ring array of isotropic elements by finding out the optimum set of elements amplitudes and phases using Differential Evolution algorithm. The said pattern is generated in three predefined azimuth planes instate of a single phi plane and also verified for a range of azimuth plane for the same optimum excitations. The main beam is steered to an elevation angle of 30 degree with lower peak SLL and ripple. Dynamic range ratio (DRR is also being improved by eliminating the weakly excited array elements, which simplify the design complexity of feed networks.

  4. Fast beam steering with full polarization control using a galvanometric optical scanner and polarization controller

    CERN Document Server

    Jofre, M; Steinlechner, F; Oliverio, N; Torres, J P; Pruneri, V; Mitchell, M W; 10.1364/OE.20.012247

    2012-01-01

    Optical beam steering is a key element in many industrial and scientific applications like in material processing, information technologies, medical imaging and laser display. Even though galvanometer-based scanners offer flexibility, speed and accuracy at a relatively low cost, they still lack the necessary control over the polarization required for certain applications. We report on the development of a polarization steerable system assembled with a fiber polarization controller and a galvanometric scanner, both controlled by a digital signal processor board. The system implements control of the polarization decoupled from the pointing direction through a feed-forward control scheme. This enables to direct optical beams to a desired direction without affecting its initial polarization state. When considering the full working field of view, we are able to compensate polarization angle errors larger than 0.2 rad, in a temporal window of less than $\\sim 20$ ms. Given the unification of components to fully cont...

  5. Dual Band and Beam-Steering Antennas Using Reconfigurable Feed on Sierpinski Structure

    Directory of Open Access Journals (Sweden)

    Seonghun Kang

    2015-01-01

    Full Text Available Fractal patch antennas based on the Sierpinski structure are studied in this paper. The antennas operate at dual bands (around 2 and 5 GHz and are designed to steer the beam directions at around 5 GHz band (the first harmonic. The antennas use reconfigurable triple feeds on the same antenna plane to have three beam directions. The same scale factor defines the geometrical self-similarity of the Sierpinski fractal. The proposed antennas are fabricated through three iterations from 1st order to 3rd order and utilize FR-4 (εr = 4.4 for the microwave substrate. The performances of the antennas, such as reflection coefficients and radiation patterns are verified by simulation and measurement. The results show that the properties of the proposed antennas in three orders are similar.

  6. Enhanced needle localization in ultrasound using beam steering and learning-based segmentation.

    Science.gov (United States)

    Hatt, Charles R; Ng, Gary; Parthasarathy, Vijay

    2015-04-01

    Segmentation of needles in ultrasound images remains a challenging problem. In this paper, we introduce a machine learning-based method for needle segmentation in 2D beam-steered ultrasound images. We used a statistical boosting approach to train a pixel-wise classifier for needle segmentation. The Radon transform was then used to find the needle position and orientation from the segmented image. We validated our method with data from ex vivo specimens and clinical nerve block procedures, and compared the results to those obtained using previously reported needle segmentation methods. Results show improved localization success and accuracy using the proposed method. For the ex vivo datasets, assuming that the needle orientation was known a priori, the needle was successfully localized in 86.2% of the images, with a mean targeting error of 0.48mm. The robustness of the proposed method to a lack of a priori knowledge of needle orientation was also demonstrated. For the clinical datasets, assuming that the needle orientation was closely aligned with the beam steering angle selected by the physician, the needle was successfully localized in 99.8% of the images, with a mean targeting error 0.19mm. These results indicate that the learning-based segmentation method may allow for increased targeting accuracy and enhanced visualization during ultrasound-guided needle procedures.

  7. High power microwave beam steering based on gyromagnetic nonlinear transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Romanchenko, I. V., E-mail: riv@lfe.hcei.tsc.ru; Rostov, V. V.; Gunin, A. V.; Konev, V. Yu. [Institute of high current electronics SB RAS, Akademichesky 2/3, 634055, Tomsk (Russian Federation)

    2015-06-07

    We demonstrate electronically controlled beam steering by high power RF pulses produced by two gyromagnetic nonlinear transmission lines (NLTLs) connected to a one high voltage driver. Each NLTL is capable of producing several ns RF pulses with peak power from 50 to 700 MW (6% standard deviation) at frequencies from 0.5 to 1.7 GHz (1% standard deviation) with 100 Hz repetition rate. Using a helix antenna allows irradiating of RF pulses with almost circular polarization and 350 MW maximum peak power, which corresponds to 350 kV effective potential of radiation. At the installation of two identical channels, we demonstrate the possibility of beam steering within ±15° in the horizontal plane by coherent RF pulses with circular polarization at 1.0 GHz center frequency. Fourfold increase in the power flux density for in-phase irradiation of RF pulses is confirmed by comparison with one-channel operation.

  8. A 24-GHz portable FMCW radar with continuous beam steering phased array (Conference Presentation)

    Science.gov (United States)

    Peng, Zhengyu; Li, Changzhi

    2017-05-01

    A portable 24-GHz frequency-modulated continuous-wave (FMCW) radar with continuous beam steering phased array is presented. This board-level integrated radar system consists of a phased array antenna, a radar transceiver and a baseband. The phased array used by the receiver is a 4-element linear array. The beam of the phased array can be continuously steered with a range of ±30° on the H-plane through an array of vector controllers. The vector controller is based on the concept of vector sum with binary-phase-shift attenuators. Each vector controller is capable of independently controlling the phase and the amplitude of each element of the linear array. The radar transceiver is based on the six-port technique. A free-running voltage controlled oscillator (VCO) is controlled by an analog "sawtooth" voltage generator to produce frequency-modulated chirp signal. This chirp signal is used as the transmitter signal, as well as the local oscillator (LO) signal to drive the six-port circuit. The transmitter antenna is a single patch antenna. In the baseband, the beat signal of the FMCW radar is detected by the six-port circuit and then processed by a laptop in real time. Experiments have been performed to reveal the capabilities of the proposed radar system for applications including indoor inverse synthetic aperture radar (ISAR) imaging, vital sign detection, and short-range navigation, etc. (This abstract is for the profiles session.)

  9. Tunable two dimensional optical beam steering with reconfigurable indium tin oxide plasmonic reflectarray metasurface

    Science.gov (United States)

    Forouzmand, A.; Mosallaei, H.

    2016-12-01

    In this paper, an electrically tunable reflectarray metasurface for two dimensional (2D) beam steering is designed by integration of a thin layer of indium tin oxide (ITO) material into a metal-insulator-metal (MIM) plasmonic unit-cell. The reflectarray is composed of square-shaped patch nanoantennas placed on a stack of insulator-ITO-metallic ground plane. The resonant characteristic of unit-cell and the accumulation of carrier density at the interface of ITO-insulator play key roles in obtaining over 250° of phase agility at around 218 terahertz (THz), by electrically varying the bias voltage. An array of unit-cells with integrated ITO and 2D voltage biasing distribution (from the side) offer the possibility of designing a reconfigurable antenna in which the main beam can be steered to relatively large angles in both θ- and φ- planes at carefully selected operating frequency. The significant advantage of this design is the dynamically adjustable radiation pattern in both azimuth and elevation planes even after fabrication.

  10. Novel Microstrip Patch Antennas with Frequency Agility, Polarization Reconfigurability, Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance

    Science.gov (United States)

    Babakhani, Behrouz

    Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency

  11. A Novel Approach to Beam Steering Using Arrays Composed of Multiple Unique Radiating Modes

    Science.gov (United States)

    Labadie, Nathan Richard

    Phased array antennas have found wide application in both radar and wireless communications systems particularly as implementation costs continue to decrease. The primary advantages of electronically scanned arrays are speed of beam scan and versatility of beamforming compared to mechanically scanned fixed beam antennas. These benefits come at the cost of a few well known design issues including element pattern rolloff and mutual coupling between elements. Our primary contribution to the field of research is the demonstration of significant improvement in phased array scan performance using multiple unique radiating modes. In short, orthogonal radiating modes have minimal coupling by definition and can also be generated with reduced rolloff at wide scan angles. In this dissertation, we present a combination of analysis, full-wave electromagnetic simulation and measured data to support our claims. The novel folded ring resonator (FRR) antenna is introduced as a wideband and multi-band element embedded in a grounded dielectric substrate. Multiple radiating modes of a small ground plane excited by a four element FRR array were also investigated. A novel hemispherical null steering antenna composed of two collocated radiating elements, each supporting a unique radiating mode, is presented in the context of an anti-jam GPS receiver application. Both the antenna aperture and active feed network were fabricated and measured showing excellent agreement with analytical and simulated data. The concept of using an antenna supporting multiple radiating modes for beam steering is also explored. A 16 element hybrid linear phased array was fabricated and measured demonstrating significantly improved scan range and scanned gain compared to a conventional phased array. This idea is expanded to 2 dimensional scanning arrays by analysis and simulation of a hybrid phased array composed of novel multiple mode monopole on patch antenna sub-arrays. Finally, we fabricated and

  12. Reflectarray for 120-GHz beam steering application: design, simulations, and measurements

    Science.gov (United States)

    Tamminen, Aleksi; Ala-Laurinaho, Juha; Gomes-Martins, David; Häkli, Janne; Koivisto, Päivi; Kärkkäinen, Mikko; Mäkelä, Sampo; Pursula, Pekka; Rantakari, Pekka; Sipilä, Markku; Säily, Jussi; Tuovinen, Reijo; Varonen, Mikko; Halonen, Kari A. I.; Luukanen, Arttu; Räisänen, Antti V.

    2012-06-01

    Development of a 120-GHz FMCW radar with a reflectarray as focusing element is described. The reflectarray is realized on a 150-mm silicon wafer and it has 3700 phase-modulating elements on it. The phase shifters have four discrete values to cover full phase modulation with 90° steps. The reflectarray element is realized with a conductor-backed coplanar waveguide patch antenna with a phase shifter coupled to it. The required phase modulation for each reflectarray element is determined with an in-house physical optics simulation combined with genetic-algorithm-based optimization. The reflectarrays are developed in two stages. First, preliminary reflectarrays with static phase shifters have been manufactured and tested at 120-GHz antenna measurement range. The static reflectarrays are found to perform as designed in their capability to steer the beam to a desired direction and to a distance of 3 m. The reflectarrays have -3-dB beam width from 1.1° to 1.3° depending on the beam tilt. After the preliminary verification with the static phase shifters, the reflectarrays will be assembled together with actively controlled MEMS-based phase shifters. The MEMS switches are controlled with dedicated high-voltage CMOS electronics, forming a system-in-a-package (SiP). First, the MEMS phase shifters are modeled, are being fabricated, and will be measured separately to verify their phase-shifting capability.

  13. SU-E-T-645: Qualification of a 2D Ionization Chamber Array for Beam Steering and Profile Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Gao, S [MD Anderson Cancer Ctr., Houston, TX (United States); Balter, P [UT MD Anderson Cancer Center, Houston, TX (United States); Rose, M [Sun Nuclear Inc., Melbourne, FL (Australia); Simon, W [Sun Nuclear Corp, Melbourne, FL (Australia)

    2015-06-15

    Purpose: Establish a procedure for beam steering and profile measurement using a 2D ionization chamber array and show equivalence to a water scanning system. Methods: Multiple photon beams (30×30cm{sup 2} field) and electron beams (25×25cm{sup 2} cone) were steered in the radial and transverse directions using Sun Nuclear’s IC PROFILER (ICP). Solid water was added during steering to ensure measurements were beyond the buildup region. With steering complete, servos were zeroed and enabled. Photon profiles were collected in a 30×30cm{sup 2} field at dmax and 2.9 cm depth for flattened and FFF beams respectively. Electron profiles were collected with a 25×25cm{sup 2} cone and effective depth (solid water + 0.9 cm intrinsic buildup) as follows: 0.9 cm (6e), 1.9 cm (9e), 2.9 cm (12e, 16e, 20e). Profiles of the same energy, field size and depth were measured in water with Sun Nuclear’s 3D SCANNER (3DS). Profiles were re-measured using the ICP after the in-water scans. Profiles measured using the ICP and 3DS were compared by (a) examining the differences in Varian’s “Point Difference Symmetry” metric, (b) visual inspection of the overlaid profile shapes and (c) calculation of point-by-point differences. Results: Comparing ICP measurements before and after water scanning showed very good agreement indicating good stability of the linac and measurement system. Comparing ICP Measurements to water phantom measurements using Varian’s symmetry metric showed agreement within 0.5% for all beams. The average magnitude of the agreement was within 0.2%. Comparing ICP Measurements to water phantom measurements using point-by-point difference showed agreement within 0.5% inside of 80% area of the field width. Conclusion: Profile agreement to within 0.5% was observed between ICP and 3DS after steering multiple energies with the ICP. This indicates that the ICP may be used for steering electron beams, and both flattened and FFF photon beams. Song Gao: Sun Nuclear

  14. Novel fabry-pérot cavity antenna with enhanced beam steering property using reconfigurable meta-surface

    Science.gov (United States)

    Xie, Peng; Wang, Guangming; Cai, Tong; Li, Haipeng; Liang, Jiangang

    2017-07-01

    Fabry-Pérot cavity (FPC) antenna is essential and widely used in communication system. However, conventional Fabry-Pérot cavity antennas suffer from limited working modes, small beam steering range, and also complex configurations. Here, we propose a novel reconfigurable meta-surface to extend the working modes of the FPC antenna, and thus enhanced beam steering angles (-54° to 54°). The reconfigurable meta-surface consists of 6 × 6 unit cells, occupying an area of 90 mm × 90 mm. The well-designed bias circuits can control the reflection phase of the meta-surface by tuning the states of the inserted PIN diodes, which results in 11 radiation directions of our FPC antenna. For experimental demonstration, we fabricate and assemble an antenna sample working at 5 GHz. Numerical and experimental results coincide well with each other, indicating enhanced radiation properties and wide applications of our FPC antenna.

  15. Ultra-Wideband, Dual-Polarized, Beam-Steering P-Band Array Antenna

    Science.gov (United States)

    duToit, Cornelis

    2014-01-01

    A dual-polarized, wide-bandwidth (200 MHz for one polarization, 100 MHz for the orthogonal polarization) antenna array at P-band was designed to be driven by NASA's EcoSAR digital beam former. EcoSAR requires two wide P-band antenna arrays mounted on the wings of an aircraft, each capable of steering its main beam up to 35deg off-boresight, allowing the twin radar beams to be steered at angles to the flight path. The science requirements are mainly for dual-polarization capability and a wide bandwidth of operation of up to 200 MHz if possible, but at least 100 MHz with high polarization port isolation and low cross-polarization. The novel design geometry can be scaled with minor modifications up to about four times higher or down to about half the current design frequencies for any application requiring a dual-polarized, wide-bandwidth steerable antenna array. EcoSAR is an airborne interferometric P-band synthetic aperture radar (SAR) research application for studying two- and three-dimensional fine-scale measurements of terrestrial ecosystem structure and biomass, which will ultimately aid in the broader study of the carbon cycle and climate change. The two 2×8 element Pband antenna arrays required by the system will be separated by a baseline of about 25 m, allowing for interferometry measurements. The wide 100-to- 200-MHz bandwidth dual-polarized beams employed will allow the determination of the amount of biomass and even tree height on the ground. To reduce the size of the patches along the boresight dimension in order to fit them into the available space, two techniques were employed. One technique is to add slots along the edges of each patch where the main electric currents are expected to flow, and the other technique is to bend the central part of the patch away from the ground plane. The latter also facilitates higher mechanical rigidity. The high port isolation of more than 40 dB was achieved by employing a highly symmetrical feed mechanism for each

  16. Ultra-thin two-dimensional transmissive anisotropic metasurfaces for polarization filter and beam steering application

    Science.gov (United States)

    Guo, Wen-Long; Wang, Guang-Ming; Li, Hai-Peng; Zhang, Kun; Cai, Tong

    2016-10-01

    We propose an anisotropic planar transmitting metasurface, which has the ability to manipulate orthogonally-polarized electromagnetic waves in the reflection and refraction modes respectively. The metasurface is composed of four layered rectangular patches spaced by three layered dielectric isolators each with a thickness of 0.15λ 0 at 15 GHz. By tailoring the sizes of the patches, the metasurface functions as a band-stop filter for the y-polarzied wave and a band-pass filter for the x-polarized wave operating from 14 GHz to 16 GHz. Moreover the phases of the transmitting x-polarized wave can be modulated at about 15 GHz, which contributes to beam steering according to the general refraction law. Experimental results are in good accordance with the simulated ones, in which the reflection efficiency is almost 100% while the transmission efficiency of the x-polarized wave reaches 80% at 15 GHz. Besides, the transmitted x-polarized wave is effectively manipulated from 14 GHz to 16 GHz. Project supported by the National Natural Science Foundation of China (Grant No. 61372034).

  17. Delay time for the onset of beam plasma discharge

    Science.gov (United States)

    Parish, J. L.; Denig, W. F.; Raitt, W. J.

    1987-01-01

    The interaction of a nonrelativistic electron beam with a neutral gas in a large chamber is considered, and the time interval before ignition of beam plasma discharge (BPD) is studied. A new theoretical expression for the time delay before BPD ignition is found as a function of the critical current necessary for BPD to be established. There are two parameters in the theoretical expression, and both are derived from two different experiments. These parameters are used to write the time evolution equation for plasma density as a function of time.

  18. A calibration concept for passive MW imaging using beam steering by frequency shift and aperture synthesis

    Science.gov (United States)

    Schreiber, Eric; Peichl, Markus; Jirousek, Matthias

    2013-10-01

    Passive microwave (MW) remote sensing is used in Earth observation missions for example to estimate the salinity of oceans or the soil moisture of landscapes. In these cases the absolute brightness temperature numbers are important for sufficient accuracy of the estimated geo-physical parameters. Consequently a suitable system calibration network is required. At DLR a radiometric demonstrator for fully-electronic MW imaging was set up at Ka-band, which is based on a combination of beam steering by frequency shift using a broadband slotted-waveguide antenna for one scanning direction, and the application of aperture synthesis for the other direction. Aperture synthesis is well known from radio astronomy, but it is still a new imaging principle for Earth observation or security applications. Hence as well new calibration techniques have to be developed for this kind of scanning mechanism. In this paper a novel approach for a noise-source based calibration method taking into account the antenna losses will be introduced. When using aperture synthesis techniques to determine the absolute brightness temperature values, it is very important, among other things, to know the exact phase transfer function of the system in order to achieve the desired radiometric resolution. Consequently our approach enables phase calibration as well. The paper outlines a proof of concept for this calibration method using a two-element interferometer called VESAS (Voll Elektronischer Scanner mit AperturSynthese) as a demonstrator. The functionality of the demonstrator and the proof of concept of the imaging principle mentioned before are written in detail in [1].

  19. Phased-Array Antenna Beam Squinting Related to Frequency Dependency of Delay Circuits

    NARCIS (Netherlands)

    Garakoui, S.K.; Klumperink, E.A.M.; Nauta, B.; Vliet, F.E. van

    2011-01-01

    Practical time delay circuits do not have a perfectly linear phase-frequency characteristic. When these delay circuits are applied in a phased-array system, this frequency dependency shows up as a frequency dependent beam direction (“beam squinting”). This paper quantifies beam squinting for a linea

  20. Demonstration of Tunable Steering and Multiplexing of Two 28 GHz Data Carrying Orbital Angular Momentum Beams Using Antenna Array

    Science.gov (United States)

    Xie, Guodong; Zhao, Zhe; Yan, Yan; Li, Long; Ren, Yongxiong; Ahmed, Nisar; Cao, Yinwen; Willner, Asher J.; Bao, Changjing; Wang, Zhe; Liu, Cong; Ziyadi, Morteza; Talwar, Shilpa; Sajuyigbe, Soji; Ashrafi, Solyman; Tur, Moshe; Molisch, Andreas F.; Willner, Alan E.

    2016-11-01

    In line-of-sight communication systems, accurate alignment between the transmitter and receiver is important to guarantee sufficient signal power at the receiver. Such alignment is even more important for orbital angular momentum (OAM) multiplexing systems since misalignment between the transmitter and receiver may cause crosstalk among channels. In this paper, we demonstrate the simultaneous generation and tunable steering of two OAM beams utilising a custom-designed circular antenna array at 28 GHz. We achieve a steering angle of up to 35 degrees from the antenna array normal. We find that (i) the steering angle of the generated OAM beams is limited by the emitting angle of the antenna elements, and (ii) a larger steering angle may degrade the mode purity of the generated OAM beams as well as induce inter-symbol-interference to each of the individual channels. Moreover, we demonstrate the transmission of two 1-Gbaud quadratic phase shift keying (QPSK) signal over the two steerable OAM beams with both multiplexed channels achieved bit error rates (BERs) of <3.8 × 10-3.

  1. Demonstration of Tunable Steering and Multiplexing of Two 28 GHz Data Carrying Orbital Angular Momentum Beams Using Antenna Array.

    Science.gov (United States)

    Xie, Guodong; Zhao, Zhe; Yan, Yan; Li, Long; Ren, Yongxiong; Ahmed, Nisar; Cao, Yinwen; Willner, Asher J; Bao, Changjing; Wang, Zhe; Liu, Cong; Ziyadi, Morteza; Talwar, Shilpa; Sajuyigbe, Soji; Ashrafi, Solyman; Tur, Moshe; Molisch, Andreas F; Willner, Alan E

    2016-11-11

    In line-of-sight communication systems, accurate alignment between the transmitter and receiver is important to guarantee sufficient signal power at the receiver. Such alignment is even more important for orbital angular momentum (OAM) multiplexing systems since misalignment between the transmitter and receiver may cause crosstalk among channels. In this paper, we demonstrate the simultaneous generation and tunable steering of two OAM beams utilising a custom-designed circular antenna array at 28 GHz. We achieve a steering angle of up to 35 degrees from the antenna array normal. We find that (i) the steering angle of the generated OAM beams is limited by the emitting angle of the antenna elements, and (ii) a larger steering angle may degrade the mode purity of the generated OAM beams as well as induce inter-symbol-interference to each of the individual channels. Moreover, we demonstrate the transmission of two 1-Gbaud quadratic phase shift keying (QPSK) signal over the two steerable OAM beams with both multiplexed channels achieved bit error rates (BERs) of <3.8 × 10(-3).

  2. Design of Vivaldi antenna array with end-fire beam steering function for 5G mobile terminals

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2015-01-01

    This manuscript proposes a new design of phased array antenna for future fifth generation (5G) cellular communications. The proposed phased array antenna is designed on a low-cost N9000 PTFE substrate with overall size of 60×120×0.8 mm3. It consists of eight 28-GHz Vivaldi antenna elements used...... to form a linear phased array in the edge region (top-side) on a mobile phone PCB. The simulated results show that the antenna has the reflection coefficient (S11) less than -10 dB in the frequency range of 27.4 to 28.6 GHz. The proposed phased array antenna has good gain, efficiency, and 3D beam steering...

  3. Small phase pattern 2D beam steering and a single LCOS design of 40 1 × 12 stacked wavelength selective switches.

    Science.gov (United States)

    Yang, Haining; Robertson, Brian; Wilkinson, Peter; Chu, Daping

    2016-05-30

    Two-dimensional beam steering by small, square, phase patterns as small as 50 × 50 pixels on a phase-only liquid crystal on silicon (LCOS) device is experimentally verified as suitable for the application of wavelength selective switches (WSSs), in terms of the diffraction efficiency and steering accuracy. This enables a proposed highly functional and versatile stacked switch architecture, where 40 independent 1 × 12 WSSs can be realised on a single 4k LCOS device. They can be configured to support a 1 × N WSSs with N≤144, or an N × N wavelength crossconnect with N≤12.

  4. Beam Steering, Focusing and Compression for Warm-Dense Matter Experiments

    Science.gov (United States)

    Lidia, S. M.; Anders, A.; Cohen, R. H.; Coleman, J. E.; Dorf, M.; Gilson, E. P.; Grote, D. P.; Jung, J. Y.; Leitner, M.; Logan, B. G.; Roy, P. K.; Sefkow, A. B.; Seidl, P. A.; Waldron, W. L.; Welch, D. R.

    2008-11-01

    The Heavy-Ion Fusion Sciences Virtual National Laboratory is pursuing an approach to target heating experiments in the Warm Dense Matter regime, using space-charge-dominated ion beams that are simultaneously longitudinally bunched and transversely focused. Axial compression leading to ˜100X current amplification and simultaneous radial focusing have led to encouraging energy deposition approaching, but still short of, the intensities required for eV-range target heating experiments. We present measurements from the Neutralized Drift Compression Experiment to reach the necessary higher beam intensities, including: (1) axial compression and radial focusing; (2) spatial and temporal distribution of energy deposition at the target plane; and (3) centroid motion of the beam spot through the pulse.

  5. Acoustic beam steering by light refraction: illustration with directivity patterns of a tilted volume photoacoustic source.

    Science.gov (United States)

    Raetz, Samuel; Dehoux, Thomas; Perton, Mathieu; Audoin, Bertrand

    2013-12-01

    The symmetry of a thermoelastic source resulting from laser absorption can be broken when the direction of light propagation in an elastic half-space is inclined relatively to the surface. This leads to an asymmetry of the directivity patterns of both compressional and shear acoustic waves. In contrast to classical surface acoustic sources, the tunable volume source allows one to take advantage of the mode conversion at the surface to control the directivity of specific modes. Physical interpretations of the evolution of the directivity patterns with the increasing light angle of incidence and of the relations between the preferential directions of compressional- and shear-wave emission are proposed. In order to compare calculated directivity patterns with measurements of normal displacement amplitudes performed on plates, a procedure is proposed to transform the directivity patterns into pseudo-directivity patterns representative of the experimental conditions. The comparison of the theoretical with measured pseudo-directivity patterns demonstrates the ability to enhance bulk-wave amplitudes and to steer specific bulk acoustic modes by adequately tuning light refraction.

  6. Generation of Graphene Surface Plasmons and Their Applications in Beam Steering

    KAUST Repository

    Farhat, Mohamed

    2015-01-01

    We propose a novel concept that uses mechanical and electronic properties of graphene to efficiently couple light to surface plasmon polaritons. A graphene-based infrared beam-former based on the concept of surface leaky-wave is also discussed. © OSA 2015.

  7. Two-dimensional analytic modeling of acoustic diffraction for ultrasonic beam steering by phased array transducers.

    Science.gov (United States)

    Wang, Tiansi; Zhang, Chong; Aleksov, Aleksandar; Salama, Islam; Kar, Aravinda

    2017-04-01

    Phased array ultrasonic transducers enable modulating the focal position of the acoustic waves, and this capability is utilized in many applications, such as medical imaging and non-destructive testing. This type of transducers also provides a mechanism to generate tilted wavefronts in acousto-optic deflectors to deflect laser beams for high precision advanced laser material processing. In this paper, a theoretical model is presented for the diffraction of ultrasonic waves emitted by several phased array transducers into an acousto-optic medium such as TeO2 crystal. A simple analytic expression is obtained for the distribution of the ultrasonic displacement field in the crystal. The model prediction is found to be in good agreement with the results of a numerical model that is based on a non-paraxial multi-Gaussian beam (NMGB) model.

  8. Infrared beam-steering using acoustically modulated surface plasmons over a graphene monolayer

    KAUST Repository

    Chen, Paiyen

    2014-09-01

    We model and design a graphene-based infrared beamformer based on the concept of leaky-wave (fast traveling wave) antennas. The excitation of infrared surface plasmon polaritons (SPPs) over a \\'one-atom-thick\\' graphene monolayer is typically associated with intrinsically \\'slow light\\'. By modulating the graphene with elastic vibrations based on flexural waves, a dynamic diffraction grating can be formed on the graphene surface, converting propagating SPPs into fast surface waves, able to radiate directive infrared beams into the background medium. This scheme allows fast on-off switching of infrared emission and dynamic tuning of its radiation pattern, beam angle and frequency of operation, by simply varying the acoustic frequency that controls the effective grating period. We envision that this graphene beamformer may be integrated into reconfigurable transmitter/receiver modules, switches and detectors for THz and infrared wireless communication, sensing, imaging and actuation systems.

  9. Current Control in ITER Steady State Plasmas With Neutral Beam Steering

    Energy Technology Data Exchange (ETDEWEB)

    R.V. Budny

    2009-09-10

    Predictions of quasi steady state DT plasmas in ITER are generated using the PTRANSP code. The plasma temperatures, densities, boundary shape, and total current (9 - 10 MA) anticipated for ITER steady state plasmas are specified. Current drive by negative ion neutral beam injection, lower-hybrid, and electron cyclotron resonance are calculated. Four modes of operation with different combinations of current drive are studied. For each mode, scans with the NNBI aimed at differing heights in the plasma are performed to study effects of current control on the q profile. The timeevolution of the currents and q are calculated to evaluate long duration transients. Quasi steady state, strongly reversed q profiles are predicted for some beam injection angles if the current drive and bootstrap currents are sufficiently large.

  10. Experimental study of delayed positive feedback control for a flexible beam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing ...

  11. Lithium niobate guided-wave beam former for steering phased-array antennas.

    Science.gov (United States)

    Armenise, M N; Passaro, V M; Noviello, G

    1994-09-10

    We present the theoretical investigation, design, and simulation of a novel guided-wave optical processor for L-band-transmission beam forming in a linear array of phased active antennas. The proposed configuration includes two contradirectional surface acoustic-wave transducers, and it is based on a Y-cut, X-propagating Ti:LiNbO(3) planar waveguide supporting the lowest-order modes of both polarizations (TE(0) and TM(0)) at the free-space wavelength λ = 0.85 µm. A detailed comparison between the processor we propose and other optical and electronic architectures reported in the literature is carried out, exhibiting a number of significant advantages in terms of weight, total chip size, and power consumption, when the number of antenna elements is greater than 50.

  12. 超声相控阵系统的聚焦特性研究%Research on Beam Focusing Behavior and Beam Steering Behavior of Ultrasonic Phased Array System

    Institute of Scientific and Technical Information of China (English)

    孙忠波; 强天鹏

    2012-01-01

    In this thesis, following ASTM E2491--2008, by experiments, we studied beam focusing behavior and beam steering behavior of ultrasonic phased array system in the case of being with and without a shear wave wedge fixed to the probe. Influence of aperture setting, focusing depth setting and steering angle setting to beam focusing behavior and beam steering behavior are studied by changing different values of these parameters. Then we summarize that,the acoustic Beam can only be focused in its near field, the method of determination of phased array beam steering limits offered in ASTM E2491 actually attribute to measure the angle resolution.%文章参照ASTME2491-2008标准,通过试验测试相控阵探头在不加装楔块以及加装横波斜楔块两种情况下声柬在工件中的聚焦特性以及偏转特性。试验变换了激发晶片数量、聚焦深度以及偏转角度等参数设置,研究了这些参数对声束聚焦特性和偏转特性的影响。结果发现,相控阵声束仅能在近场区内聚焦,ASTME2491-2008标准对角度偏转极限测试实际表征的是某种情况下的角度分辨力。

  13. Time-delayed beam splitting with energy separation of x-ray channels

    CERN Document Server

    Stetsko, Yuri P; Stephenson, G Brian

    2013-01-01

    We introduce a time-delayed beam splitting method based on the energy separation of x-ray photon beams. It is implemented and theoretically substantiated on an example of an x-ray optical scheme similar to that of the classical Michelson interferometer. The splitter/mixer uses Bragg-case diffraction from a thin diamond crystal. Another two diamond crystals are used as back-reflectors. For energy separation the back-reflectors are set at slightly different temperatures and angular deviations from exact backscattering. Because of energy separation and a minimal number (three) of optical elements, the split-delay line has high efficiency and is simple to operate. Due to the high transparency of diamond crystal, the split-delay line can be used in a beam sharing mode at x-ray free-electron laser facilities. The delay line can be made more compact by adding a fourth crystal.

  14. Time-delayed beam splitting with energy separation of x-ray channels

    Energy Technology Data Exchange (ETDEWEB)

    Stetsko, Yuri P.; Shvyd' ko, Yuri V.; Brian Stephenson, G. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2013-10-21

    We introduce a time-delayed beam splitting method based on the energy separation of x-ray photon beams. It is implemented and theoretically substantiated on an example of an x-ray optical scheme similar to that of the classical Michelson interferometer. The splitter/mixer uses Bragg-case diffraction from a thin diamond crystal. Another two diamond crystals are used as back-reflectors. Because of energy separation and a minimal number (three) of optical elements, the split-delay line has high efficiency and is simple to operate. Due to the high transparency of diamond crystal, the split-delay line can be used in a beam sharing mode at x-ray free-electron laser facilities.

  15. Control of Halo-Chaos in Beam Transport Network via Neural Network Adaptation with Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; LUO Xiao-Shu; HUANG Guo-Xian

    2006-01-01

    Subject of the halo-chaos control in beam transport networks (channels) has become a key concerned issue for many important applications of high-current proton beam since 1990'. In this paper, the magnetic field adaptive control based on the neuralnetwork with time-delayed feedback is proposed for suppressing beam halo-chaos in the beam transport network with periodic focusing channels. The envelope radius of high-current proton beam is controlled to reach the matched beam radius by suitably selecting the control structure and parameter of the neural network, adjusting the delayed-time and control coefficient of the neural network.

  16. 20 MHz Forward-imaging Single-element Beam Steering with an Internal Rotating Variable-Angle Reflecting Surface: Wire phantom and Ex vivo pilot study

    Science.gov (United States)

    Raphael, David T.; Li, Xiang; Park, Jinhyoung; Chen, Ruimin; Chabok, Hamid; Barukh, Arthur; Zhou, Qifa; Elgazery, Mahmoud; Shung, K. Kirk

    2012-01-01

    Feasibility is demonstrated for a forward-imaging beam steering system involving a single-element 20 MHz angled-face acoustic transducer combined with an internal rotating variable-angle reflecting surface (VARS). Rotation of the VARS structure, for a fixed position of the transducer, generates a 2-D angular sector scan. If these VARS revolutions were to be accompanied by successive rotations of the single-element transducer, 3-D imaging would be achieved. In the design of this device, a single-element 20 MHz PMN-PT press-focused angled-face transducer is focused on the circle of midpoints of a micro-machined VARS within the distal end of an endoscope. The 2-D imaging system was tested in water bath experiments with phantom wire structures at a depth of 10 mm, and exhibited an axial resolution of 66 μm and a lateral resolution of 520 μm. Chirp coded excitation was used to enhance the signal-to-noise ratio, and to increase the depth of penetration. Images of an ex vivo cow eye were obtained. This VARS-based approach offers a novel forward-looking beam-steering method, which could be useful in intra-cavity imaging. PMID:23122968

  17. Quantum steering in cascaded four-wave mixing processes.

    Science.gov (United States)

    Wang, Li; Lv, Shuchao; Jing, Jietai

    2017-07-24

    Quantum steering is used to describe the "spooky action-at-a-distance" nonlocality raised in the Einstein-Podolsky-Rosen (EPR) paradox, which is important for understanding entanglement distribution and constructing quantum networks. Here, in this paper, we study an experimentally feasible scheme for generating quantum steering based on cascaded four-wave-mixing (FWM) processes in hot rubidium (Rb) vapor. Quantum steering, including bipartite steering and genuine tripartite steering among the output light fields, is theoretically analyzed. We find the corresponding gain regions in which the bipartite and tripartite steering exist. The results of bipartite steering can be used to establish a hierarchical steering model in which one beam can steer the other two beams in the whole gain region; however, the other two beams cannot steer the first beam simultaneously. Moreover, the other two beams cannot steer with each other in the whole gain region. More importantly, we investigate the gain dependence of the existence of the genuine tripartite steering and we find that the genuine tripartite steering exists in most of the whole gain region in the ideal case. Also we discuss the effect of losses on the genuine tripartite steering. Our results pave the way to experimental demonstration of quantum steering in cascaded FWM process.

  18. On utilizing delayed feedback for active-multimode vibration control of cantilever beams

    Science.gov (United States)

    Alhazza, Khaled A.; Nayfeh, Ali H.; Daqaq, Mohammed F.

    2009-01-01

    We present a single-input single-output multimode delayed-feedback control methodology to mitigate the free vibrations of a flexible cantilever beam. For the purpose of controller design and stability analysis, we consider a reduced-order model consisting of the first n vibration modes. The temporal variation of these modes is represented by a set of nonlinearly coupled ordinary-differential equations that capture the evolving dynamics of the beam. Considering a linearized version of these equations, we derive a set of analytical conditions that are solved numerically to assess the stability of the closed-loop system. To verify these conditions, we characterize the stability boundaries using the first two vibration modes and compare them to damping contours obtained by long-time integration of the full nonlinear equations of motion. Simulations show excellent agreement between both approaches. We analyze the effect of the size and location of the piezoelectric patch and the location of the sensor on the stability of the response. We show that the stability boundaries are highly dependent on these parameters. Finally, we implement the controller on a cantilever beam for different controller gain-delay combinations and assess the performance using time histories of the beam response. Numerical simulations clearly demonstrate the controller ability to mitigate vibrations emanating from multiple modes simultaneously.

  19. Steering handbook

    CERN Document Server

    Pfeffer, Peter

    2017-01-01

    This edited volume presents basic principles as well as advanced concepts of the computational modeling of steering systems. Moreover, the book includes the components and functionalities of modern steering system, which are presented comprehensively and in a practical way. The book is written by more than 15 leading experts from the automotive industry and its components suppliers. The target audience primarily comprises practicing engineers, developers, researchers as well as graduate students who want to specialize in this field.

  20. Implementation of a Novel Low-Cost Low-Profile Ku-Band Antenna Array for Single Beam Steering from Space

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2013-01-01

    Phased array antennas afford many advantages over traditional reflector antennas due to their conformality, high aperture efficiency, and unfettered beam steering capability at the price of increased cost and complexity. This paper eliminates the complex and costly array backend via the implementation of a series fed array employing a propagation constant reconfigurable transmission line connecting each element in series. Scanning can then be accomplished through one small (less than or equal to 100mil) linear motion that controls propagation constant. Specifically, each element is fed via a reconfigurable coplanar stripline transmission line with a tapered dielectric insert positioned between the transmission line traces. The dielectric insert is allowed to move up and down to control propagation constant and therefore induce scanning. We present a 20 element patch array design, scanning from -25 deg. less than or equal to theta less than or equal to 21 deg. at 13GHz. Measurements achieve only10.5 deg. less than or equal to theta less than or equal to 22 deg. scanning due to a faulty, yet correctable, manufacturing process. Beam squint is measured to be plus or minus 3 deg. for a 600MHz bandwidth. This prototype was improved to give scanning of 3.5 deg. less than or equal to theta less than or equal to 22 deg. Cross-pol patterns were shown to be -15dB below the main beam. Simulations accounting for fabrication errors match measured patterns, thus validating the designs.

  1. Compact optical true time delay beamformer for a 2D phased array antenna using tunable dispersive elements.

    Science.gov (United States)

    Ye, Xingwei; Zhang, Fangzheng; Pan, Shilong

    2016-09-01

    A hardware-compressive optical true time delay architecture for 2D beam steering in a planar phased array antenna is proposed using fiber-Bragg-grating-based tunable dispersive elements (TDEs). For an M×N array, the proposed system utilizes N TDEs and M wavelength-fixed optical carriers to control the time delays. Both azimuth and elevation beam steering are realized by programming the settings of the TDEs. An experiment is carried out to demonstrate the delay controlling in a 2×2 array, which is fed by a wideband pulsed signal. Radiation patterns calculated from the experimentally measured waveforms at the four antennas match well with the theoretical results.

  2. Ping-Pong Beam Training for Reciprocal Channels with Delay Spread

    DEFF Research Database (Denmark)

    Carvalho, Elisabeth De; Andersen, Jørgen Bach

    2015-01-01

    We present an iterative beam training procedure for a reciprocal channel with delay spread between two massive antenna arrays. The primary application is communication at millimeter wave frequencies. The procedure is based on ping pong transmissions. For each matricial channel coefficient......, it tracks the left and right singular vectors associated to the maximal singular value. Based on the set of singular vectors, we build transmit and receive equalizers. A simple equalization based on matched filtering is showed to be optimal in the case of a Gaussian i.i.d. channel and a sparse channel....

  3. Use of VUV Imaging to Evaluate COTR and Beam-Steering Effects in a SASE FEL at 130 nm

    CERN Document Server

    Lumpkin, Alex H; Dejus, Roger J; Erdmann, Mark; Lewellen, John W; Li, Yuelin

    2004-01-01

    We have continued to explore VUV operations on the Advanced Photon Source (APS) self-amplified spontaneous emission (SASE) free-electron laser (FEL). With the installation of a fifth VUV imaging station located after undulator 7 of an eight-undulator series, we have performed our most complete SASE gain curve measurements at 130 nm as well as obtaining beam profile, position, and divergence information. This is the shortest wavelength to date for our complementary coherent optical transition radiation (COTR) measurements. We have also done the first experimental test of Tanaka et al.’s analytical model for the effects of a single-kick error of the e-beam on gain and microbunching in a SASE FEL. In addition, we compared the e-beam image centroid positions with those of the alignment laser at the available cameras and the local rf BPM readings to sort out the effective trajectory and its effect on overall gain. The FEL performance was consistent with GENESIS simulations of the experiment described in detail in...

  4. Performance assessment of PEFP steering magnet

    Energy Technology Data Exchange (ETDEWEB)

    Han, S. H.; Jeo, Y. S. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    PEFP LEBT uses two solenoid and two steering magnets for the beam position and angle control at the RFQ match point. The dependence of magnetic field and coil temperature on time was assessed and the linearity was also measured.

  5. $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

    CERN Multimedia

    We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

  6. Mechanical 144 GHz beam steering with all-metallic epsilon-near-zero lens antenna

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco-Peña, V., E-mail: victor.pacheco@unavarra.es; Torres, V., E-mail: victor.torres@unavarra.es; Orazbayev, B., E-mail: b.orazbayev@unavarra.es; Beruete, M., E-mail: miguel.beruete@unavarra.es; Sorolla, M. [Antennas Group-TERALAB, Universidad Pública de Navarra, Campus Arrosadía, 31006 Pamplona (Spain); Navarro-Cía, M., E-mail: m.navarro@imperial.ac.uk [Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2BT (United Kingdom); Centre for Plasmonics and Metamaterials, Imperial College London, London SW7 2AZ (United Kingdom); Centre for Terahertz Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Engheta, N., E-mail: engheta@ee.upenn.edu [Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2014-12-15

    An all-metallic steerable beam antenna composed of an ε-near-zero (ENZ) metamaterial lens is experimentally demonstrated at 144 GHz (λ{sub 0} = 2.083 mm). The ENZ lens is realized by an array of narrow hollow rectangular waveguides working just near and above the cut-off of the TE{sub 10} mode. The lens focal arc on the xz-plane is initially estimated analytically as well as numerically and compared with experimental results demonstrating good agreement. Next, a flange-ended WR-6.5 waveguide is placed along the lens focal arc to evaluate the ENZ-lens antenna steerability. A gain scan loss below 3 dB is achieved for angles up to ±15°.

  7. Improving Delay-Margin of Noncollocated Vibration Control of Piezo-Actuated Flexible Beams via a Fractional-Order Controller

    Directory of Open Access Journals (Sweden)

    Teerawat Sangpet

    2014-01-01

    Full Text Available Noncollocated control of flexible structures results in nonminimum-phase systems because the separation between the actuator and the sensor creates an input-output delay. The delay can deteriorate stability of closed-loop systems. This paper presents a simple approach to improve the delay-margin of the noncollocated vibration control of piezo-actuated flexible beams using a fractional-order controller. Results of real life experiments illustrate efficiency of the controller and show that the fractional-order controller has better stability robustness than the integer-order controller.

  8. Switched steerable multiple beam antenna system

    Science.gov (United States)

    Iwasaki, Richard S. (Inventor)

    1988-01-01

    A steerable multibeam five element cross-feed cluster antenna system is described. The feed power is divided into five branches. Each branch includes a switching network comprised of a plurality of time delay elements each individually controlled by a respective electromagnetic latching switch. Frequency independent individual two-dimensional beam steering at intermediate (IF) scanning frequencies is thereby provided wherein discrete incremental time delays are introduced by the switching networks into each branch and the signals recombined thereafter to form each beam. The electromagnetic latched switching reduces power consumption and permits higher power switching and reciprocal coincident tranmsit and receive operation. Frequency independence due to incremental time delay switching permits coincident reciprocal operation and steering for transmit-receive signal paths carrying different transmit-receive frequencies. Diagonal quarter wave plates in the waveguides alter polarization from the circular to orthogonal linear to provide transmitter-receiver isolation.

  9. Structural and composition investigations at delayered locations of low k integrated circuit device by gas-assisted focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dandan, E-mail: dandan.wang@globalfoundries.com; Kee Tan, Pik; Yamin Huang, Maggie; Lam, Jeffrey; Mai, Zhihong [Technology Development Department, GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D, Street 2, Singapore 738406 (Singapore)

    2014-05-15

    The authors report a new delayering technique – gas-assisted focused ion beam (FIB) method and its effects on the top layer materials of integrated circuit (IC) device. It demonstrates a highly efficient failure analysis with investigations on the precise location. After removing the dielectric layers under the bombardment of an ion beam, the chemical composition of the top layer was altered with the reduced oxygen content. Further energy-dispersive x-ray spectroscopy and Fourier transform infrared analysis revealed that the oxygen reduction lead to appreciable silicon suboxide formation. Our findings with structural and composition alteration of dielectric layer after FIB delayering open up a new insight avenue for the failure analysis in IC devices.

  10. 235U Determination using In-Beam Delayed Neutron Counting Technique at the NRU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M. T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bentoumi, G. [Canadian Nuclear Labs., Chalk River, ON (Canada); Corcoran, E. C. [Royal Military College of Canada, Kingston, ON (United States); Dimayuga, I. [Canadian Nuclear Labs., Chalk River, ON (Canada); Kelly, D. G. [Royal Military College of Canada, Kingston, ON (United States); Li, L. [Canadian Nuclear Labs., Chalk River, ON (Canada); Sur, B. [Canadian Nuclear Labs., Chalk River, ON (Canada); Rogge, R. B. [Canadian Nuclear Labs., Chalk River, ON (Canada)

    2015-11-17

    This paper describes a collaborative effort that saw the Royal Military College of Canada (RMC)’s delayed neutron and gamma counting apparatus transported to Canadian Nuclear Laboratories (CNL) for use in the neutron beamline at the National Research Universal (NRU) reactor. Samples containing mg quantities of fissile material were re-interrogated, and their delayed neutron emissions measured. This collaboration offers significant advantages to previous delayed neutron research at both CNL and RMC. This paper details the determination of 235U content in enriched uranium via the assay of in-beam delayed neutron magnitudes and temporal behavior. 235U mass was determined with an average absolute error of ± 2.7 %. This error is lower than that obtained at RMCC for the assay of 235U content in aqueous solutions (3.6 %) using delayed neutron counting. Delayed neutron counting has been demonstrated to be a rapid, accurate, and precise method for special nuclear material detection and identification.

  11. Steering Performance, Tactical Vehicles

    Science.gov (United States)

    2015-07-29

    NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Automotive Instrumentation Division (TEDT-AT-AD-I) U.S. Army Aberdeen Test Center 400...characterize the on-center vehicle responses of military vehicles for the purposes of influencing vehicle design and ensuring military truck steering... mechanism attached to the test vehicle’s steering wheel (or replaces the steering wheel) that is strain gaged and calibrated to measure the steering effort

  12. Quantum steering without inequalities

    CERN Document Server

    Chen, Jing-Ling; Wu, Chunfeng; Su, Hong-Yi; Cabello, Adan; Kwek, L C; Oh, C H

    2012-01-01

    We show that, for any two-qubit state, quantum steering can be proven without testing the violation of steering inequalities. We show that steerability is proven if Bob's normalized conditional states after Alice's measurements are pure. This method, which may be seen as the quantum steering analog of Greenberger-Horne-Zeilinger-like tests of Bell nonlocality without Bell inequalities, offers advantages with respect to the existing methods for experimentally testing quantum steering.

  13. Delayed-Phase Cone-Beam CT Improves Detectability of Intrahepatic Cholangiocarcinoma During Conventional Transarterial Chemoembolization

    Energy Technology Data Exchange (ETDEWEB)

    Schernthaner, Ruediger Egbert [The Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology (United States); Lin, MingDe [Philips Research North America, Ultrasound and Interventions (United States); Duran, Rafael; Chapiro, Julius; Wang, Zhijun; Geschwind, Jean-François, E-mail: jfg@jhmi.edu [The Johns Hopkins Hospital, Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology (United States)

    2015-08-15

    PurposeTo evaluate the detectability of intrahepatic cholangiocarcinoma (ICC) on dual-phase cone-beam CT (DPCBCT) during conventional transarterial chemoembolization (cTACE) compared to that of digital subtraction angiography (DSA) with respect to pre-procedure contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.MethodsThis retrospective study included 17 consecutive patients (10 male, mean age 64) with ICC who underwent pre-procedure CE-MRI of the liver, and DSA and DPCBCT (early-arterial phase (EAP) and delayed-arterial phase (DAP)) just before cTACE. The visibility of each ICC lesion was graded by two radiologists on a three-rank scale (complete, partial, and none) on DPCBCT and DSA images, and then compared to pre-procedure CE-MRI.ResultsOf 61 ICC lesions, only 45.9 % were depicted by DSA, whereas EAP- and DAP-CBCT yielded a significantly higher detectability rate of 73.8 % and 93.4 %, respectively (p < 0.01). Out of the 33 lesions missed on DSA, 18 (54.5 %) and 30 (90.9 %) were revealed on EAP- and DAP-CBCT images, respectively. DSA depicted only one lesion that was missed by DPCBCT due to streak artifacts caused by a prosthetic mitral valve. DAP-CBCT identified significantly more lesions than EAP-CBCT (p < 0.01). Conversely, EAP-CBCT did not detect lesions missed by DAP-CBCT. For complete lesion visibility, DAP-CBCT yielded significantly higher detectability (78.7 %) compared to EAP (31.1 %) and DSA (21.3 %) (p < 0.01).ConclusionDPCBCT, and especially the DAP-CBCT, significantly improved the detectability of ICC lesions during cTACE compared to DSA. We recommend the routine use of DAP-CBCT in patients with ICC for per-procedure detectability and treatment planning in the setting of TACE.

  14. rf deflector design of the CLIC test facility CTF3 delay loop and beam loading effect analysis

    Directory of Open Access Journals (Sweden)

    David Alesini

    2009-03-01

    Full Text Available Beam injection and extraction in the delay loop of the CLIC Test Facility 3 (CTF3 for recombination of adjacent bunch trains, is performed by a specially designed rf deflector. A standing wave structure has been chosen for this purpose. Three possible solutions have been investigated, and a comparative analysis is presented. All of them satisfy the essential requirements of the system up to the maximum foreseen energy with the existing klystron. The final design of the rf deflector consists of two identical cavities connected to the rf power source through a hybrid junction that equally splits the power and isolates the klystron from reflections. The rf deflector design, the results of electromagnetic simulations, and the low level rf measurements are illustrated. The impact of beam loading in the rf deflectors on the transverse beam dynamics is also analyzed. The general expression of the single passage transverse wakefield is obtained and a dedicated tracking code has been written to study the multibunch multiturn effects. A complete analysis for different machine parameters and injection errors is presented and discussed. These numerical simulations indicate a tolerable beam emittance growth due to the transverse wakefield in the rf deflectors.

  15. Analysis of delayed convergence in the three-noded Timoshenko beam element using the function space approach

    Indian Academy of Sciences (India)

    Somenath Mukherjee; Gangan Prathap

    2002-10-01

    Despite satisfying only completeness and continuity requirements, elements often perform erroneously in a certain class of problems, called the locking situations, where they display spurious stress oscillations and enhanced stiffness properties. The function space approach that effectively substantiates the postulates of the field consistency paradigm is an efficient tool to reveal the fundamental cause of locking phenomena, and propose methods to eliminate this pathological problem. In this paper, we review the delayed convergence behaviour of three-noded Timoshenko beam elements using the rigorous function space approach. Explicit, closed form algebraic results for the element strains, stresses and errors have been derived using this method. The performance of the field-inconsistent three-noded Timoshenko beam element is compared with that of the field-inconsistent twonoded beam element. It is demonstrated that while the field-inconsistent two-noded linear element is prone to shear locking, the field-inconsistent three-noded element is not very vulnerable to this pathological problem, despite the resulting shear oscillations.

  16. Staggered delay tuning algorithms for ring resonators in optical beam forming networks

    NARCIS (Netherlands)

    Blokpoel, R.J.

    2007-01-01

    The Telecommunication Engineering group at the University of Twente is currently working on two projects about phased array antenna systems with photonic beam-formers. One is the SMart Antenna systems for Radio Transceivers (SMART) project. The other is the Broadband Photonic Beamformer project. Som

  17. Steering and evasion assist

    NARCIS (Netherlands)

    Dang, T.; Desens, J.; Franke, U.; Gavrila, D.; Schäfers, L.; Ziegler, W.; Eskandarian, A.

    2012-01-01

    Steering and evasion assistance defines a new and future class of driver assistance systems to avoid an impending collision with other traffic participants. Dynamic and kinematic considerations reveal that an evasive steering maneuver has high potential for collision avoidance in many driving

  18. Experimental temporal quantum steering

    Science.gov (United States)

    Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

    2016-01-01

    Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks. Thus, these results can lead to applications for secure quantum communications and quantum engineering. PMID:27901121

  19. Beryllium window and acoustic delay line design for x-ray lithography beam lines at the University of Wisconsin Center for X-ray Lithography

    Science.gov (United States)

    Brodsky, E. L.; Hamilton, W.; Wells, G.; Cerrina, F.; Corradini, M.

    1992-01-01

    X-ray lithography systems require sample chambers that can perform exposures in helium gas at atmospheric pressure. The interface between the experimental chamber and the beamline is critical for x-ray lithography and the storage ring. It must allow a high x-ray flux throughput while providing a vacuum barrier so that helium gas does not leak into the beam line and the storage ring. The beam line must also be designed to have protection in the case that a window does fail in order to minimize adverse effects to the ring and other systems. The details of the design for the vacuum system used on beam lines for the Center for X-ray Lithography at the University of Wisconsin Synchrotron Radiation Center 1-GeV electron storage ring are reported. Curved beryllium windows with a 1×5-cm2 aperture and 13 μm thick that have a leak rate less than 10-10 Torr l/s have been successfully used at the experimental chamber beam-line interface. This thin flat beryllium foil is mounted in a curved housing with a wire seal to minimize helium leakage. The window assembly is designed and has been tested to withstand substantial overpressure before failure. If the beryllium window does fail, the beamline has an acoustic delay line that is designed to delay the incoming shock wave of helium gas so that a fast valve at the end of the beam line will close and minimize leakage of helium into the storage ring. The acoustic delay line is designed with baffles to slow the shock front and a secondary thin window to protect against molecular diffusion into the storage ring. The acoustic delay line has been tested to determine the effect of baffle design on delay of the shock wave. A theoretical model that provides a good description of the acoustic delay has also been developed.

  20. Fermilab Steering Group Report

    Energy Technology Data Exchange (ETDEWEB)

    Steering Group, Fermilab; /Fermilab

    2007-12-01

    The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOvA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC development by accelerating the

  1. Fermilab Steering Group Report

    Energy Technology Data Exchange (ETDEWEB)

    Beier, Eugene; /Pennsylvania U.; Butler, Joel; /Fermilab; Dawson, Sally; /Brookhaven; Edwards, Helen; /Fermilab; Himel, Thomas; /SLAC; Holmes, Stephen; /Fermilab; Kim, Young-Kee; /Fermilab /Chicago U.; Lankford, Andrew; /UC, Irvine; McGinnis, David; /Fermilab; Nagaitsev, Sergei; /Fermilab; Raubenheimer, Tor; /SLAC /Fermilab

    2007-01-01

    The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOVA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC development by accelerating the

  2. Method of steering a vehicle

    NARCIS (Netherlands)

    Della Penna, M.; Van Passen, M.M.; Abbink, D.A.; Mulder, M.

    2011-01-01

    Vehicle and method of steering such a vehicle, wherein the vehicle has a steering wheel and steerable driving wheels and a transfer system for converting steering wheel actions to a steering angle of the steerable driving wheels, and wherein the transfer system is provided with a predefined stiffnes

  3. Design of Pneumatic Collapsible Steering

    Directory of Open Access Journals (Sweden)

    Anish Nair

    2013-08-01

    Full Text Available The steering wheel is the important cause of fatal injury for drivers in frontal collision. When frontal collision occurs, due to the kinetic energy of driver or occupant body, it moves forward against steering wheel and wind shield. Actually in a frontal collision forces will be first transmitted through driver’s feet which act as fulcrum so the body will rotate about it. For the taller driver steering works as fulcrum. Driver head & chest hit the steering or windshield which may cause severe injury or death. Considering the injury potential of steering wheel we are presenting a new idea Pneumatic Collapsible Steering Column (PCS.

  4. Splash events First Beams 2008

    CERN Multimedia

    Collaboration, CMS

    2008-01-01

    First beam through the detector: images showing the debris, or "splash", of particles picked up in the detector's calorimeters and muon chambers after the beam was steered into the collimator (tungsten blocks) at Point 5.

  5. CCCT - Patient Advocate Steering Committee

    Science.gov (United States)

    The Patient Advocate Steering Committee (PASC) works to ensure advocates involved with the Scientific Steering Committees (SSCs) are completely integrated in the development, implementation, and monitoring of clinical trials within those groups.

  6. 49 CFR 570.60 - Steering system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering system. 570.60 Section 570.60... 10,000 Pounds § 570.60 Steering system. (a) System play. Lash or free play in the steering system... excessive lash or free play in the steering system. Table 2. Steering Wheel Free Play Values Steering...

  7. 49 CFR 570.7 - Steering systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering systems. 570.7 Section 570.7... Pounds or Less § 570.7 Steering systems. (a) System play. Lash or free play in the steering system shall... in the steering system. Table 1—Steering System Free Play Values Steering wheel diameter (inches...

  8. Dental cone beam computed tomography analyses of postoperative labial bone thickness in maxillary anterior implants: comparing immediate and delayed implant placement.

    Science.gov (United States)

    Miyamoto, Yasukazu; Obama, Tadakazu

    2011-06-01

    This study aimed to evaluate the influence of labial alveolar bone thickness and the corresponding vertical bone loss on postoperative gingival recessions around anterior maxillary dental implants. Using cone beam computed tomography (CBCT) scanning, the temporal changes of three-dimensional images of alveolar bone were monitored to determine hard and soft tissue outcomes of two different implant placement techniques: delayed two-stage and immediate placement. Furthermore, for the delayed two-stage placement, guided bone regeneration was applied using either nonresorbable or resorbable membranes combined with anorganic bovine bone matrix. The comparative results suggested that gingival recessions were significantly lower in delayed two-stage placement, especially when using a nonresorbable membrane, compared to immediate placement, and labial bone thickness, measured by CBCT, offered an effectual indicator to assess gingival recession in the anterior region.

  9. Electrical steering of vehicles

    DEFF Research Database (Denmark)

    Blanke, Mogens; Thomsen, Jesper Sandberg

    2006-01-01

    solutions and still meet strict requirements to functional safety. The paper applies graph-based analysis of functional system structure to find a novel fault-tolerant architecture for an electrical steering where a dedicated AC-motor design and cheap voltage measurements ensure ability to detect all...

  10. Steering Your Mysterious Mind

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    Steering the Mysterious Mind, describes a unique, novel concept for a way to gain control of your mind. The five basic elements of human life, that is; Creativity, Content­ment, Confidence, Calmness, and Concentration (C5) have been introduced in my previous book Unlock Your Personalization...

  11. Improvement for the steering performance of liquid crystal phased array

    Institute of Scientific and Technical Information of China (English)

    SONG Yan; KONG Ling-jiang; CHEN Jun; ZHU Ying; YANG Jian-yu

    2009-01-01

    Optical phased array technology is introduced and the steering performances of liquid crystal phased array are discussed, several factors affecting the beam steering performances arc analyzed completely, also simple models for some typical factors are developed. Then, a new method based on iterating and modifying the output phase pattern of liquid crystal phase shifters is proposed. Using this method, the modified voltages applied on electrodes of liquid crystal phase shifters can be obtained, after applying the voltages, the influence of factors can be compensated to some extent; the steering angle accu-racy and efficiency with liquid crystal phased array can be improved. Through the simulation for the angle range from 0° to -1°, the error of steering angle can be reduced three orders of magnitude, and the efficiency can be increased almost 30% after several iterations.

  12. Beam injection into RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.; Hahn, H.; MacKay, W.W.; Satogata, T.; Tsoupas, N.; Zhang, W.

    1997-07-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. The authors describe the injection zone and its bottlenecks. They report on the commissioning of the injection system, on beam based measurements of the kickers and the application program to steer the beam.

  13. Steering Your Mysterious Mind

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    well-being is key for happy and stress free life. Mind has enormous energy. Everyone has access to tre­mendous mental energies; what matters is being aware of this and to work on concentrating your energy into creative work. To achieve mental strength, C5 is a su­preme powerful exercise for the mind......Steering the Mysterious Mind, describes a unique, novel concept for a way to gain control of your mind. The five basic elements of human life, that is; Creativity, Content­ment, Confidence, Calmness, and Concentration (C5) have been introduced in my previous book Unlock Your Personalization....... Compare it with going to the gym where you work on the physical body. In the same way as with arms and legs, the mind is a mus­cle which you exercise through C5 practice. Steering the mind on your personal goal will help you to be creative....

  14. Optimization of Steering Elements in the RIA Driver Linac

    CERN Document Server

    SchnirmanLessner, Eliane; Ostroumov, Peter

    2005-01-01

    The driver linac of the projected RIA facility is a versatile accelerator, a 1.4-GV, CW superconducting linac designed to simultaneously accelerate several heavy-ion charge states, providing beams from protons at about 1 GeV to uranium at 400 MeV/u at power levels at a minimum of 100 kW and up to 400 kW for most beams. Acceleration of multiple-charge-state uranium beams places stringent requirements on the linac design. A steering algorithm was derived that fulfilled the driver’s real estate requirements, such as placement of steering dipole coils on SC solenoids and of beam position monitors outside cryostats, and beam-dynamics requirements, such as coupling effects induced by the focusing solenoids.* The algorithm has been fully integrated in the tracking code TRACK** and is used to study and optimize the number and position of steering elements that minimize the multiple-beam centroid oscillations and preserve the beam emittance under misalignments of accelerating and transverse focusing elements...

  15. Impact of Electron Collision Mixing on the delay times of an electron beam excited Atomic Xenon laser

    NARCIS (Netherlands)

    Peters, Peter J.; Lan, Yun Fu; Ohwa, Mieko; Kushner, Mark J.

    1990-01-01

    The atomic xenon (5d¿6p) infrared laser has been experimentally and theoretically investigated using a short-pulse (30-ns), high-power (1-10-MW/cm3) coaxial electron beam excitation source. In most cases, laser oscillation is not observed during the e-beam current pulse. Laser pulses of hundreds of

  16. Acousto-Optic Beam Steering Study

    Science.gov (United States)

    1994-08-01

    fito for each poin: displayed While (Not COF(l)) ’Keep getting data until the end of the tile Input tI, Cormnd ’get the next Command Select Case UCJseS...8217AND STCBE WRITE LI14E to advance fito counted Call WRTLN(2) ’FIFO 1 OR 2 End Sub Sub DR•MOULTI (ByVal X As Single, ByVal Y As Single) ’routine to

  17. Loophole-free quantum steering

    CERN Document Server

    Wittmann, Bernhard; Steinlechner, Fabian; Langford, Nathan K; Brunner, Nicolas; Wiseman, Howard; Ursin, Rupert; Zeilinger, Anton

    2011-01-01

    Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories 1-6. However, there still remains the crucial challenge of simultaneously closing all major loopholes - the locality, freedom-of-choice, and detection loopholes - in a single experiment. An important sub-class of local realistic theories can be tested with the concept of "steering". The term steering was introduced by Schr\\"odinger in 1935 for the fact that entanglement would seem to allow an experimenter to remotely steer the state of a distant system 7. Einstein called this "spooky action at a distance" 8. Steering has recently been rigorously formulated as a quantum information task opening it up to new experimental tests 9-11. Here, we present the first loophole-free demonstration of steering by violating three-setting quadratic steering inequality, tested with polarization entangled photons shared between two distant laboratories. Our experiment demonstrates this effect w...

  18. Computational Steering with Reduced Complexity

    OpenAIRE

    Butnaru, Daniel

    2014-01-01

    Computational Steering increases the understanding of relationships between the output of a simulation and its parametrized input, such as boundary conditions, physical parameters, or domain geometry. Steering relies on a running simulation which delivers results to a visualization system. However, many simulation codes cannot deliver the required interactive results. For the first time, this work investigates the use of surrogate models to augment computational steering approaches. Based...

  19. Quadrupole Law and Steering Options in the Linac4 DTL

    CERN Document Server

    Stovall, J

    2009-01-01

    The Linac4 drift-tube linac (DTL) reference design has been modified to reduce the power consumption in tank 1 by adjusting the accelerating field and phase laws. In this note we investigate three options for the transverse focusing lattice, quadrupole law, and two options for beam steering. We use acceptance, sensitivity to alignment errors and the probabiity of beam loss as figures of merit for evaluating each option.

  20. Research on the Variable Steering Ratio of Four-Wheel-Steering Vehicle

    Institute of Scientific and Technical Information of China (English)

    林程; 陈思忠; 任良成

    2004-01-01

    The steering characteristic of a four-wheel-steering vehicle is numerically simulated for in-depth research of the handling stability of four-wheel steering. The research results show that the deteriorating tendency of the steering stability due to the increase of the vehicle speed is improved obviously in the case of four-wheel steering. The approach of variable steering ratio is discussed. The use of the variable steering ratio can not only raise the steering stability of vechicles at high vehicle speed, but also reduce the dicomfort and steering burden of drivers; and hence is helpful for the subjective evaluation of four-wheel steering vehicles.

  1. Quantum coherence of steered states

    Science.gov (United States)

    Hu, Xueyuan; Milne, Antony; Zhang, Boyang; Fan, Heng

    2016-01-01

    Lying at the heart of quantum mechanics, coherence has recently been studied as a key resource in quantum information theory. Quantum steering, a fundamental notion originally considered by Schödinger, has also recently received much attention. When Alice and Bob share a correlated quantum system, Alice can perform a local measurement to ‘steer’ Bob’s reduced state. We introduce the maximal steered coherence as a measure describing the extent to which steering can remotely create coherence; more precisely, we find the maximal coherence of Bob’s steered state in the eigenbasis of his original reduced state, where maximization is performed over all positive-operator valued measurements for Alice. We prove that maximal steered coherence vanishes for quantum-classical states whilst reaching a maximum for pure entangled states with full Schmidt rank. Although invariant under local unitary operations, maximal steered coherence may be increased when Bob performs a channel. For a two-qubit state we find that Bob’s channel can increase maximal steered coherence if and only if it is neither unital nor semi-classical, which coincides with the condition for increasing discord. Our results show that the power of steering for coherence generation, though related to discord, is distinct from existing measures of quantum correlation.

  2. Experimental analysis of beam pointing system based on liquid crystal optical phase array

    Science.gov (United States)

    Shi, Yubin; Zhang, Jianmin; Zhang, Zhen

    2016-12-01

    In this paper, we propose and demonstrate an elementary non-mechanical beam aiming and steering system with a single liquid crystal optical phase array (LC-OPA) and charge-coupled device (CCD). With the conventional method of beam steering control, the LC-OPA device can realize one dimensional beam steering continuously. An improved beam steering strategy is applied to realize two dimensional beam steering with a single LC-OPA. The whole beam aiming and steering system, including an LC-OPA and a retroreflective target, is controlled by the monitor. We test the feasibility of beam steering strategy both in one dimension and in two dimension at first, then the whole system is build up based on the improved strategy. The experimental results show that the max experimental pointing error is 56 μrad, and the average pointing error of the system is 19 μrad.

  3. Performance Analyses of the Radio Orbital Angular Momentum Steering Technique Based on Ka-Band Antenna

    Directory of Open Access Journals (Sweden)

    Mingtuan Lin

    2017-01-01

    Full Text Available The misalignment in the orbital angular momentum- (OAM- based system would distort the radiation patterns of twisted beams carrying OAM, consequently making the OAM-based communication infeasible. To tackle the misalignment problem, a radio OAM steering technique based on a uniform circular array (UCA is illustrated. Subsequently, simulations are conducted to explore the influence of the OAM steering on the OAM mode quality and transmission performance. Furthermore, UCAs working at Ka-band with formulated feeding networks are designed and fabricated to analyze the performance of the OAM steering. The influences of OAM steering on mode quality and orthogonality are then evaluated in the experiment. Overall, the analyses of OAM steering technique are beneficial for the development of radio OAM study.

  4. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase II project is to fabricate, characterize, and verify performance of a new type of frequency steered acoustic transducer...

  5. Quantification of Gaussian quantum steering

    CERN Document Server

    Kogias, Ioannis; Ragy, Sammy; Adesso, Gerardo

    2014-01-01

    Einstein-Podolsky-Rosen steering incarnates a useful nonclassical correlation which sits in-between entanglement and Bell nonlocality. While a number of qualitative steering criteria exist, very little has been achieved for what concerns quantifying steerability. We introduce a computable measure of steering for arbitrary bipartite Gaussian states of continuous variable systems. For two-mode Gaussian states, the measure reduces to a form of coherent information, which is proven never to exceed entanglement, and to reduce to it on pure states. We provide an operational connection between our measure and the key rate in one-sided device-independent quantum key distribution. We further prove that steering bound entangled Gaussian states by Gaussian measurements is impossible.

  6. STEER Coastal Use Mapping Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Use Mapping Project is designed to collect critical information on human activities in and near the St. Thomas East End Reserves (STEER). The project...

  7. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is to develop, fabricate, and characterize a novel frequency steered acoustic transducer (FSAT) for the...

  8. STEER Coastal Use Mapping Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Use Mapping Project is designed to collect critical information on human activities in and near the St. Thomas East End Reserves (STEER). The project...

  9. Responder fast steering mirror

    Science.gov (United States)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  10. Current steering effect of GaN nanoporous structure

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chia-Feng, E-mail: cflin@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States); Wang, Jing-Hao; Cheng, Po-Fu; Tseng, Wang-Po; Fan, Feng-Hsu; Wu, Kaun-Chun; Lee, Wen-Che [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Han, Jung [Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States)

    2014-11-03

    Current steering effect of InGaN light emitting diode (LED) structure was demonstrated by forming a high resistivity GaN nanoporous structure. Disk-array patterns with current-injection bridge structures were fabricated on InGaN LED devices through a focused ion beam (FIB) system. GaN nanoporous structure was formed around the FIB-drilled holes through a electrochemical (EC) wet-etching process on a n-type GaN:Si layer under the InGaN active layer. High emission intensity and small peak wavelength blueshift phenomenon of the electroluminescence spectra were observed in the EC-treated region compared with the non-treated region. The branch-like nanoporous structure was formed along the lateral etched direction to steer the injection current in 5 μm-width bridge structures. In the FIB-drilled hole structure, high light emission intensity of the central-disk region was observed by enlarging the bridge width to 10 μm, with a 5 μm EC-treated width, that reduced the current steering effect and increased the light scattering effect on the nanoporous structure. The EC-treated GaN:Si nanoporous structure acted as a high light scattering structure and a current steering structure that has potential on the current confinement for vertical cavity surface emitting laser applications. - Highlights: • High resistivity nanoporous-GaN formed in InGaN LED through electrochemical process. • Branch-like nanoporous in 5 μm-width bridge structure can steer the injection current. • Nanoporous GaN acted as s light scattering and current steering structures in InGaN LED.

  11. Beam director design report

    Energy Technology Data Exchange (ETDEWEB)

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  12. Superdirective dielectric nanoantennas with effect of light steering

    CERN Document Server

    Krasnok, Alexander; Slobozhanyuk, Alexey; Simovski, Constantin; Belov, Pavel; Kivshar, Yuri

    2013-01-01

    We introduce a novel concept of superdirective antennas based on the generation of higher-order optically-induced magnetic multipole modes. All-dielectric nanoantenna can be realized as an optically small spherical dielectric nanoparticle with a notch excited by a point source (e.g. a quantum dot) located in the notch. The superdirectivity effect is not associated with high dissipative losses. For these dielectric nanoantennas we predict the effect of the beam steering at the nanoscale characterized by a subwavelength sensitivity of the beam radiation direction to the source position. We confirm the predicted effects experimentally through the scaling to the microwave frequency range.

  13. Variable Delay With Directly-Modulated R-SOA and Optical Filters for Adaptive Antenna Radio-Fiber Access

    DEFF Research Database (Denmark)

    Prince, Kamau; Presi, Marco; Chiuchiarelli, Andrea

    2009-01-01

    on a directly-modulated reflective emiconductor amplifier (R-SOA) and exploits the interplay between transmission-line dispersion and tunable optical filtering to achieve flexible true time delay, with $2pi$ beam steering at the different antennas. The system was characterized, then successfully tested with two......We present an all-optical adaptive-antenna radio over fiber transport system that uses proven, commercially-available components to effectively deliver standard-compliant optical signaling to adaptive multiantenna arrays for current and emerging radio technology implementations. The system is based...

  14. Multi-Layer Traffic Steering

    DEFF Research Database (Denmark)

    Fotiadis, Panagiotis; Polignano, Michele; Gimenez, Lucas Chavarria

    2013-01-01

    This paper investigates the potentials of traffic steering in the Radio Resource Control (RRC) Idle state by evaluating the Absolute Priorities (AP) framework in a multilayer Long Term Evolution (LTE) macrocell scenario. Frequency priorities are broadcast on the system information and RRC Idle...... users can be steered towards higher priority carriers whenever coverage allows it. However, such an approach may overload the prioritized layers. For that purpose, an enhanced scheme is proposed, where priorities are adjusted on a user basis and are provided to the terminal via the connection release...

  15. Joint Measurability and Temporal Steering

    OpenAIRE

    Karthik, H. S.; Tej, J Prabhu; Devi, A. R. Usha; Rajagopal, A. K.

    2014-01-01

    Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only i...

  16. Bulling among yearling feedlot steers.

    Science.gov (United States)

    Pierson, R E; Jensen, R; Braddy, P M; Horton, D P; Christie, R M

    1976-09-01

    In a survey to determine the cause of illness and deaths among yearling feedlot cattle, bulling was found to be one of the major problems. During the years 1971-1974, 54,913 (2.88%) steers became bullers and represented an annual loss of around +325,000. Some of the causes of bulling were found to be hormones, either as implants or in the feed. In 1974, from 1,988 necropsies, it was determined that 83 steers died from riding injuries.

  17. Mechanisms of ovipositor insertion and steering of a parasitic wasp.

    Science.gov (United States)

    Cerkvenik, Uroš; van de Straat, Bram; Gussekloo, Sander W S; van Leeuwen, Johan L

    2017-09-12

    Drilling into solid substrates with slender beam-like structures is a mechanical challenge, but is regularly done by female parasitic wasps. The wasp inserts her ovipositor into solid substrates to deposit eggs in hosts, and even seems capable of steering the ovipositor while drilling. The ovipositor generally consists of three longitudinally connected valves that can slide along each other. Alternative valve movements have been hypothesized to be involved in ovipositor damage avoidance and steering during drilling. However, none of the hypotheses have been tested in vivo. We used 3D and 2D motion analysis to quantify the probing behavior of the fruit-fly parasitoid Diachasmimorpha longicaudata (Braconidae) at the levels of the ovipositor and its individual valves. We show that the wasps can steer and curve their ovipositors in any direction relative to their body axis. In a soft substrate, the ovipositors can be inserted without reciprocal motion of the valves. In a stiff substrate, such motions were always observed. This is in agreement with the damage avoidance hypothesis of insertion, as they presumably limit the overall net pushing force. Steering can be achieved by varying the asymmetry of the distal part of the ovipositor by protracting one valve set with respect to the other. Tip asymmetry is enhanced by curving of ventral elements in the absence of an opposing force, possibly due to pretension. Our findings deepen the knowledge of the functioning and evolution of the ovipositor in hymenopterans and may help to improve man-made steerable probes.

  18. 46 CFR 176.814 - Steering systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST...) INSPECTION AND CERTIFICATION Material Inspections § 176.814 Steering systems. At each initial and subsequent inspection for certification the owner or managing operator shall be prepared to test the steering systems of...

  19. A survey of computational steering environments

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van; Liere, R. van

    1998-01-01

    Computational steering is a powerful concept that allows scientists to interactively control a computational process during its execution. In this paper, a survey of computational steering environments for the on-line steering of ongoing scientific and engineering simulations is presented. These env

  20. Beam Techniques - Beam Control and Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Minty, Michiko G

    2003-04-24

    We describe commonly used strategies for the control of charged particle beams and the manipulation of their properties. Emphasis is placed on relativistic beams in linear accelerators and storage rings. After a brief review of linear optics, we discuss basic and advanced beam control techniques, such as transverse and longitudinal lattice diagnostics, matching, orbit correction and steering, beam-based alignment, and linac emittance preservation. A variety of methods for the manipulation of particle beam properties are also presented, for instance, bunch length and energy compression, bunch rotation, changes to the damping partition number, and beam collimation. The different procedures are illustrated by examples from various accelerators. Special topics include injection and extraction methods, beam cooling, spin transport and polarization.

  1. Objective Evaluation Method of Steering Comfort Based on Movement Quality Evaluation of Driver Steering Maneuver

    Institute of Scientific and Technical Information of China (English)

    YANG Yiyong; LIU Yahui; WANG Man; JI Run; JI Xuewu

    2014-01-01

    The existing research of steering comfort mainly focuses on the subjective evaluation, aiming at designing and optimizing the steering system. In the development of steering system, especially the evaluation of steering comfort, the objective evaluation methods considered the kinematic characteristics of driver steering maneuver are not proposed, which means that the objective evaluation of steering cannot be conducted with the evaluation of kinematic characteristics of driver in steering maneuver. In order to propose the objective evaluation methods of steering comfort, the evaluation of steering movement quality of driver is developed on the basis of the study of the kinematic characteristics of steering maneuver. First, the steering motion trajectories of the driver in both comfortable and certain extreme uncomfortable operation conditions are detected using the Vicon motion capture system. The operation conditions are under the restrictions of the vertical height and horizontal distance between steering wheel center and the H-point of driver, and the steering resisting torque else. Next, the movement quality evaluation of driver steering maneuver is assessed using twelve kinds of evaluation indices based on the kinematic analyses of the steering motion trajectories to propose an objective evaluation method. Finally, an integrated discomfort index of steering maneuver is proposed on the basis of the regression analysis of subjective evaluation rating and the movement quality evaluation indices, including the Jerk, Discomfort and Joint Torque indices. The test results show that the proposed integrated discomfort index gives a good fitting with the subjective evaluation of discomfort, which means it can be used to evaluate or predict the discomfort level of steering maneuver. This paper proposes an objective evaluation method of steering comfort based on the movement quality evaluation of driver steering maneuver.

  2. HUMAN-SIMULATING VEHICLE STEERING CONTROL ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    XU Youchun; LI Keqiang; CHANG Ming; CHEN Jun

    2006-01-01

    A new vehicle steering control algorithm is presented. Unlike the traditional methods do,the algorithm uses a sigmoid function to describe the principle of the human driver's steering strategy.Based on this function, a human simulating vehicle steering model, human-simulating steering control(HS) algorithm is designed. In order to improve the adaptability to different environments, a parameter adaptive adjustment algorithm is presented. This algorithm can online modify the value of the key parameters of the HS real time. HS controller is used on a vehicle equipped with computer vision system and computer controlled steering actuator system, the result from the automatic vehicle steering experiment shows that the HS algorithm gives good performance at different speed, even at the maximum speed of 172 km/h.

  3. 46 CFR 182.610 - Main steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  4. 同波束干涉测量差分相时延观测模型研究及验证%Research and Verification of Differential Phase Delay Measurement Model of Same Beam Interferometry

    Institute of Scientific and Technical Information of China (English)

    陈少伍; 董光亮; 李海涛; 刘庆会; 陈冠磊; 郑鑫

    2013-01-01

    The model of differential phase delay of same beam interferometry (SBI) is analyzed according to the requirement for the high accuracy ground based guidance and navigation of the lunar orbit rendezvous and docking mission.The differential phase delay measurement model of same beam interferometry is propagated based on the same wave front definition of very long baseline interferometry (VLBI).An accurate differential phase delay closure algorithm of same beam interfemmetry is derived based on the definition of the same wave front of SBI and the geometry delay closure algorithm of VLBI.The value of differential phase delay closure is calculated by using the observation data of the SELENE mission of Japan,and the result shows that the accuracy of differential phase delay closure is in the range of 0.5~1 ps.The algorithm given in the paper could evidently reduce tends of differential phase delay closure,and the validity of the measurement model is verified in this paper.It is of some significance for high accuracy ground-based navigation of the forthcoming lunar orbit rendezvous and docking mission.%针对月球轨道交会对接地面高精度引导需求,对同波束干涉测量差分相延观测模型进行分析验证.根据甚长基线干涉测量几何时延观测量同一波前的定义,推导出同波束差分时延观测量的观测模型.并提出一种精确的同波束干涉测量差分相时延闭合算法,同时结合SELENE任务实测的数据计算差分相时延闭合值,用于对观测模型进行验证.实测数据计算结果表明,采用本文提出的精确算法显著地消除同一波前差分相时延闭合值中的趋势项,差分相时延闭合值的精度在0.5ps~l ps范围内,验证了观测模型的正确性.该研究对于后续的月球交会对接地面高精度测定轨任务分析设计将具有一定的参考价值.

  5. Controller Design for Electric Power Steering System Using T-S Fuzzy Model Approach

    Institute of Scientific and Technical Information of China (English)

    Xin Li; Xue-Ping Zhao; Jie Chen

    2009-01-01

    Pressure ripples in electric power steering (EPS) systems can be caused by the phase lag between the driver's steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno (T-S) fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation (PDC) structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality (LMI) problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.

  6. Driver behavior following an automatic steering intervention.

    Science.gov (United States)

    Fricke, Nicola; Griesche, Stefan; Schieben, Anna; Hesse, Tobias; Baumann, Martin

    2015-10-01

    The study investigated driver behavior toward an automatic steering intervention of a collision mitigation system. Forty participants were tested in a driving simulator and confronted with an inevitable collision. They performed a naïve drive and afterwards a repeated exposure in which they were told to hold the steering wheel loosely. In a third drive they experienced a false alarm situation. Data on driving behavior, i.e. steering and braking behavior as well as subjective data was assessed in the scenarios. Results showed that most participants held on to the steering wheel strongly or counter-steered during the system intervention during the first encounter. Moreover, subjective data collected after the first drive showed that the majority of drivers was not aware of the system intervention. Data from the repeated drive in which participants were instructed to hold the steering wheel loosely, led to significantly more participants holding the steering wheel loosely and thus complying with the instruction. This study seems to imply that without knowledge and information of the system about an upcoming intervention, the most prevalent driving behavior is a strong reaction with the steering wheel similar to an automatic steering reflex which decreases the system's effectiveness. Results of the second drive show some potential for countermeasures, such as informing drivers shortly before a system intervention in order to prevent inhibiting reactions.

  7. Correlation steering in the angularly multimode Raman atomic memory.

    Science.gov (United States)

    Mazelanik, Mateusz; Dąbrowski, Michał; Wasilewski, Wojciech

    2016-09-19

    We present the possibility of steering the direction of correlations between the off-resonant Raman scattered photons from the angularly multimode atomic memory based on warm rubidium vapors. Using acousto-optic deflectors (AOD) driven by different modulation frequencies, we experimentally change the angle of incidence of the laser beams on the atomic ensemble. By performing correlation measurements for various deflection angles, we verify that we can choose the anti-Stokes light propagation direction independently of the correlated Stokes scattered light in a continuous way. As a result we can select the spatial mode of photons retrieved from the memory, which may be important for future development of quantum information processing.

  8. Steering light into logic patterns with two-dimensional cascaded multimode waveguide

    Institute of Scientific and Technical Information of China (English)

    Zhou Hai-Feng; Yang Jian-Yi; Wang Ming-Hua; Jiang Xiao-Qing

    2007-01-01

    Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated.By employing the imaging properties of 2D multimode interference (MMI) and partial phase modulation method,the design ideas and the implementing methods of the 2(2×2) bits type spatial logic steering are discussed;therefore the structure of logical pattern is proposed.Numerical simulation is carried out to verify the design in detail by using the beam propagation method.It is expected to realize logic coders by using the integrated optical methods and exploit their potential applications in the field of optical logic.

  9. Steering control system for a mobile robot

    Science.gov (United States)

    Kolli, Kaylan C.; Hall, Ernest L.

    1997-09-01

    Automated guided vehicles (AGVs) have many potential applications in manufacturing, medicine, space and defense. The purpose of this paper is to describe the design of a steering mechanism for an autonomous mobile robot. The steering mechanism replaces a manually turned rack and pinion arrangement with a crank mechanism driven by a linear actuator that in turn is powered by a brushless dc motor. The system was modeled, analyzed, and redesigned to meet the requirements. A 486 computer through a 3-axis motion controller supervises the steering control. The steering motor is a brushless dc motor powered by three phase signals. It is run in current loop mode. The steering control system is supervised by a personal computer through a multi-axis motion controller. Testing of these systems has been done in the lab as well as on an outside test track with positive results.

  10. Wireless traffic steering for green cellular networks

    CERN Document Server

    Zhang, Shan; Zhou, Sheng; Niu, Zhisheng; Shen, Xuemin (Sherman)

    2016-01-01

    This book introduces wireless traffic steering as a paradigm to realize green communication in multi-tier heterogeneous cellular networks. By matching network resources and dynamic mobile traffic demand, traffic steering helps to reduce on-grid power consumption with on-demand services provided. This book reviews existing solutions from the perspectives of energy consumption reduction and renewable energy harvesting. Specifically, it explains how traffic steering can improve energy efficiency through intelligent traffic-resource matching. Several promising traffic steering approaches for dynamic network planning and renewable energy demand-supply balancing are discussed. This book presents an energy-aware traffic steering method for networks with energy harvesting, which optimizes the traffic allocated to each cell based on the renewable energy status. Renewable energy demand-supply balancing is a key factor in energy dynamics, aimed at enhancing renewable energy sustainability to reduce on-grid energy consum...

  11. Adjustment procedure for beam alignment in scanned ion-beam therapy

    Science.gov (United States)

    Saraya, Y.; Takeshita, E.; Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Tansho, R.; Shirai, T.; Noda, K.

    2016-09-01

    Control of the beam position for three-dimensional pencil-beam scanning is important because the position accuracy of the beam significantly impacts the alignment of the irradiation field. To suppress this effect, we have developed a simple procedure for beamline tuning. At first, beamline tuning is performed with steering magnets and fluorescent screen monitors to converge the beam's trajectory to a central orbit. Misalignment between the beam's position and the reference axis is checked by using the verification system, which consists of a screen monitor and an acrylic phantom. If the beam position deviates from the reference axis, two pairs of steering magnets, which are placed on downstream of the beam transport line, will be corrected. These adjustments are iterated until the deviations for eleven energies of the beam are within 0.5 mm of the reference axis. To demonstrate the success of our procedure, we used our procedure to perform beam commissioning at the Kanagawa Cancer Center.

  12. Time-delay feedback control and stability analysis of piezoelectric-coupling cantilever beam%压电耦合悬臂梁的时滞反馈控制及稳定性分析

    Institute of Scientific and Technical Information of China (English)

    冯志宏; 霍睿

    2011-01-01

    Based on the closed-up control strategy of acceleration time-delay feedback, a dynamics model of piezoelectric-coupling flexible cantilever beam was set up.The stability conditions and dynamic characteristics of the system were achieved via conducting the modal analysis and free vibration trivial solutions analysis.The effects of piezoelectric coupling and time delay were considered and a specific example was presented to proof the previous results.The example shows that ignoring time-delay unreasonably may cause the system to respond divergently, while a reasonable amount of time-delay can improve the efficiency of vibration control.%基于加速度-时滞闭环反馈控制策略,建立压电耦合柔性悬臂梁的动力学模型,通过运用模态分析和对系统自由振动的平凡解的分析,建立了在考虑压电耦合作用和反馈时滞条件下的系统稳定性条件和分析方法,并给出了具体算例;进一步的算例分析表明,时滞的不合理忽略有可能导致系统响应发散,而合理的时滞量也可用以提高振动控制的效率.

  13. The effect of electronically steering a phased array ultrasound transducer on near-field tissue heating

    Science.gov (United States)

    Payne, Allison; Vyas, Urvi; Todd, Nick; Bever, Joshua de; Christensen, Douglas A.; Parker, Dennis L.

    2011-01-01

    Purpose: This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating. Methods: The thermal response of a nine-position raster and a 16-mm diameter circle scanning trajectory executed through both electronic and mechanical scanning was evaluated in computer simulations and experimentally in a homogeneous tissue-mimicking phantom. Simulations were performed using power deposition maps obtained from the hybrid angular spectrum (HAS) method and applying a finite-difference approximation of the Pennes’ bioheat transfer equation for the experimentally used transducer and also for a fully sampled transducer to demonstrate the effect of acoustic window, ultrasound beam overlap and grating lobe clutter on near-field heating. Results: Both simulation and experimental results show that electronically steering the ultrasound beam for the two trajectories using the 256-element phased array significantly increases the thermal dose deposited in the near-field tissues when compared with the same treatment executed through mechanical steering only. In addition, the individual contributions of both beam overlap and grating lobe clutter to the near-field thermal effects were determined through comparing the simulated ultrasound beam patterns and resulting temperature fields from mechanically and electronically steered trajectories using the 256-randomized element phased array transducer to an electronically steered trajectory using a fully sampled transducer with 40 401 phase-adjusted sample points. Conclusions: Three distinctly different three distinctly different transducers were simulated to analyze the tradeoffs of selected transducer design parameters on near-field heating. Careful consideration of design tradeoffs and accurate patient treatment planning combined with thorough monitoring of the near-field tissue temperature will

  14. The effect of electronically steering a phased array ultrasound transducer on near-field tissue heating.

    Science.gov (United States)

    Payne, Allison; Vyas, Urvi; Todd, Nick; de Bever, Joshua; Christensen, Douglas A; Parker, Dennis L

    2011-09-01

    This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating. The thermal response of a nine-position raster and a 16-mm diameter circle scanning trajectory executed through both electronic and mechanical scanning was evaluated in computer simulations and experimentally in a homogeneous tissue-mimicking phantom. Simulations were performed using power deposition maps obtained from the hybrid angular spectrum (HAS) method and applying a finite-difference approximation of the Pennes' bioheat transfer equation for the experimentally used transducer and also for a fully sampled transducer to demonstrate the effect of acoustic window, ultrasound beam overlap and grating lobe clutter on near-field heating. Both simulation and experimental results show that electronically steering the ultrasound beam for the two trajectories using the 256-element phased array significantly increases the thermal dose deposited in the near-field tissues when compared with the same treatment executed through mechanical steering only. In addition, the individual contributions of both beam overlap and grating lobe clutter to the near-field thermal effects were determined through comparing the simulated ultrasound beam patterns and resulting temperature fields from mechanically and electronically steered trajectories using the 256-randomized element phased array transducer to an electronically steered trajectory using a fully sampled transducer with 40 401 phase-adjusted sample points. Three distinctly different three distinctly different transducers were simulated to analyze the tradeoffs of selected transducer design parameters on near-field heating. Careful consideration of design tradeoffs and accurate patient treatment planning combined with thorough monitoring of the near-field tissue temperature will help to ensure patient safety during an MRg

  15. Emittance growth from electron beam modulation

    Energy Technology Data Exchange (ETDEWEB)

    Blaskiewicz, M.

    2009-12-01

    In linac ring colliders like MeRHIC and eRHIC a modulation of the electron bunch can lead to a modulation of the beam beam tune shift and steering errors. These modulations can lead to emittance growth. This note presents simple formulas to estimate these effects which generalize some previous results.

  16. Networked Control System for the Guidance of a Four-Wheel Steering Agricultural Robotic Platform

    Directory of Open Access Journals (Sweden)

    Eduardo Paciência Godoy

    2012-01-01

    Full Text Available A current trend in the agricultural area is the development of mobile robots and autonomous vehicles for precision agriculture (PA. One of the major challenges in the design of these robots is the development of the electronic architecture for the control of the devices. In a joint project among research institutions and a private company in Brazil a multifunctional robotic platform for information acquisition in PA is being designed. This platform has as main characteristics four-wheel propulsion and independent steering, adjustable width, span of 1,80 m in height, diesel engine, hydraulic system, and a CAN-based networked control system (NCS. This paper presents a NCS solution for the platform guidance by the four-wheel hydraulic steering distributed control. The control strategy, centered on the robot manipulators control theory, is based on the difference between the desired and actual position and considering the angular speed of the wheels. The results demonstrate that the NCS was simple and efficient, providing suitable steering performance for the platform guidance. Even though the simplicity of the NCS solution developed, it also overcame some verified control challenges in the robot guidance system design such as the hydraulic system delay, nonlinearities in the steering actuators, and inertia in the steering system due the friction of different terrains.

  17. Joint measurability and temporal steering [Invited

    Science.gov (United States)

    Karthik, H. S.; Prabhu Tej, J.; Usha Devi, A. R.; Rajagopal, A. K.

    2015-04-01

    Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only if it exhibits temporal steering.

  18. 46 CFR 108.641 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  19. 46 CFR 169.623 - Power-driven steering systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Power-driven steering systems. 169.623 Section 169.623 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Machinery and Electrical Steering Systems § 169.623 Power-driven steering systems. (a) Power-driven steering...

  20. Needle steering for robot-assisted insertion into soft tissue: A survey

    Science.gov (United States)

    Gao, Dedong; Lei, Yong; Zheng, Haojun

    2012-07-01

    Needle insertion is a common surgical procedure used in diagnosis and treatment. The needle steering technologies make continuous developments in theoretical and practical aspects along with the in-depth research on needle insertion. It is necessary to summarize and analyze the existing results to promote the future development of theories and applications of needle insertion. Thus, a survey of the state of the art of research is presented on algorithms of needle steering techniques, the surgical robots and devices. Based on the analysis of the needle insertion procedure, the concept of needle steering is defined as a kinematics problem, which is to place the needle at the target and avoid the obstacles. The needle steering techniques, including the artificial potential field method and the nonholonomic model, are introduced to control the needles for improving the accuracy. Based on the quasi-static thinking, the virtual spring model and the cantilever-beam model are developed to calculate the amount of needle deflection and generate the needle path. The phantoms instead of the real tissue are used to verify the models mentioned in most of the experimentations. For the desired needle trajectories, the image-guided robotic devices and some novel needles are presented to achieve the needle steering. Finally, the challenges are provided involving the controllability of the long flexible needle and the properties of soft tissue. The results and investigations can be used for further study on the precision and accuracy of needle insertion.

  1. Design of a remote steering antenna for ECRH heating in the stellarator Wendelstein 7-X

    Energy Technology Data Exchange (ETDEWEB)

    Plaum, B., E-mail: plaum@igvp.uni-stuttgart.de [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Univ. Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Lechte, C.; Kasparek, W.; Gaiser, S.; Zeitler, A. [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Univ. Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Erckmann, V. [Max-Planck-Institut für Plasmaphysik, EURATOM-IPP, D-17491 Greifswald (Germany); Weißgerber, M. [Max-Planck-Institut für Plasmaphysik, EURATOM-IPP, D-85748 Garching (Germany); Bechtold, A. [NTG Neue Technologie GmbH & Co KG, D-63571 Gelnhausen (Germany); Busch, M.; Szcepaniak, B. [Galvano-T electroplating-electroforming GmbH, D-51570 Windeck-Rosbach (Germany)

    2015-10-15

    Highlights: • We report about the design activities for the remote steering antennas for the stellarator W7-X. • The integration into the W7-X system and the manufacturing procedure are described. • Simulations and loss measurements for the waveguide walls were done and are in good agreement. • A method for extending the steering range is presented. • A mechanical deformation analysis showed that the deformation is not critical for the beam quality. - Abstract: For the ECRH heating system of the stellarator Wendelstein 7-X, two remote steering antennas are developed and manufactured. The principle of remote steering antennas is based on the imaging characteristics of corrugated rectangular waveguides, which is well understood and can accurately be simulated. Several details, however, require deeper investigation. The antenna needs a miter-bend and a 24 mm gap. The positions of these elements need to be chosen carefully to reduce losses and stray radiation. The antennas are manufactured from copper by electroforming. This allows to integrate all components, including the corrugated inner walls and the cooling channels, in one vacuum-tight piece. This paper reviews the design process of the remote steering antennas for W7-X as well as technological issues and experimental results from test pieces.

  2. Steer-by-wire steering system with enhanced functionality for rear steered vehicles

    Directory of Open Access Journals (Sweden)

    Christoph Dillmann

    2015-12-01

    Full Text Available Heckgelenkte selbstfahrende Erntemaschinen sind die zentralen Elemente moderner Ernteketten in der Landwirtschaft. Das primär auf Bodenschonung ausgelegte Fahrwerk, die aktuelle Höchstgeschwindigkeit von 40 km/h sowie die systembedingten, fahrdynamischen Nachteile einer heckgelenkten Maschine erschweren jedoch die Fahrzeugführung auf der Straße. Das Spurhalten und Stabilisieren erfordert daher viel Erfahrung und eine hohe Konzentration des Fahrers. Fahrdynamiksysteme können den Fahrzeugführer entlasten und somit das Fahren mit hohen Geschwindigkeiten sicherer und komfortabler gestalten. Im hier vorgestellten Projekt wird in diesem Kontext eine Steer-by-wire-Lenkung mit parametrierbarer Lenkcharakteristik vorgestellt, die auf die unterschiedlichen Vorzüge des Fahrers einstellbar ist und fahrzustandsabhängige Informationen über das Lenkrad an den Bediener übermittelt.

  3. Control And Transport Of Intense Electron Beams

    CERN Document Server

    Li, H

    2004-01-01

    The transport of intense beams for advanced accelerator applications with high-intensity beams such as heavy-ion inertial fusion, spallation neutron sources, and intense light sources requires tight control of beam characteristics over long distances. The University of Maryland Electron Ring (UMER), which uses low energy, high current electron beams to model the transport physics of intense space-charge-dominated beams, employs real-time beam characterization and control in order to optimize beam quality throughout the strong focusing lattice. We describe in this dissertation the main beam control techniques used in UMER, which include optimal beam steering by quadrupole scans, beam rotation correction using a skew corrector, rms envelope matching and optimization, empirical envelope matching, beam injection, and phase space reconstruction using a tomographic method. Using these control techniques, we achieved the design goals for UMER. The procedure is not only indispensable for optimum beam transport over l...

  4. Time-Delayed Velocity-Acceleration Feedback for Active Vibration Control of Cantilever Beam%基于速度-加速度时滞反馈的振动主动控制

    Institute of Scientific and Technical Information of China (English)

    安方; 陈卫东; 邵敏强

    2012-01-01

    The design problem of the time-delayed controller with the measured acceleration signal is presented, which is used to neutralize the effect of the group delay induced by the low-pass filter on active vibration control systems. By means of the reduction method and the state-derivative feedback strategy, a time-delayed velocity-acceleration feedback controller is proposed without the inclusion of the displacement signal, so that the accumulation errors caused by twice integration of the acceleration signal can be avoided. The developed time delayed feedback controller is examined by the computer simulation, with a special focusing on the control performance of a cantilever beam with the piezoelectric actuator and the acceleration sensor. Simulation results demonstrate that the controller can effectively reduce the free vibration response of the intelligent cantilever beam, and compared with the velocity-acceleration feedback controller, it has better control effects at different time delays.%在振动主动控制中,基于加速度测量信号,并考虑滤波器群时延引入的时滞,研究了一种时滞控制器设计方法.采用等维方法和状态导数反馈思想,提出一种速度-加速度时滞反馈控制器的设计方法.该控制器不含位移信号,可省去两次数值积分和去直流分量、趋势项这两个过程,并可避免由两次数值积分带来的累积误差.以粘帖有压电陶瓷和加速度传感器的智能梁为控制对象,采用该控制器控制其自由振动,并与速度-加速度反馈控制效果进行比较.仿真结果表明,当采用速度-加速度反馈直接控制时滞系统时,若时滞超出其稳定区间,该方法失效,而速度-加速度时滞反馈控制方法则具有良好的控制效果.

  5. CCCT - NCTN Steering Committees - Gynecologic Cancers

    Science.gov (United States)

    The Gynecologic Cancers Steering Committee evaluates and prioritizes concepts for phase 2 and 3 clinical trials in adult gynecologic cancers. The GCSC is also intent on fostering collaboration with international groups and institutions conducting trials.

  6. Omni rotational driving and steering wheel

    DEFF Research Database (Denmark)

    2008-01-01

    Abstract of WO 2008138346  (A1) There is disclosed a driving and steering wheel (112) module (102) with an omni rotational part (106), the module comprising a flange part (104) fixable on a robot, and the omni rotational part (106) comprises an upper omni rotational part (105) and a driving...... and steering wheel part (108), where the omni rotational part (106) is provided for infinite rotation relative to the flange part (104) by both a drive motor (110) and a steering motor (114) being positionable on the flange part (104), and the driving and steering wheel part (108) is suspended from the upper...... omni rotational part (105) with a suspension (116) such that wheel part (108) can move relatively to the upper omni rotational part (105) in a suspension direction (118), and a reduction gear (120) for gearing the drive torque is provided in the wheel part (108) in order e.g. to assure traction...

  7. CCCT - NCTN Steering Committees - Clinical Imaging

    Science.gov (United States)

    The Clinical Imaging Steering Committee serves as a forum for the extramural imaging and oncology communities to provide strategic input to the NCI regarding its significant investment in imaging activities in clinical trials.

  8. CCCT - NCORP Cancer Control Steering Committees

    Science.gov (United States)

    The National Community Oncology Research Program (NCORP) Steering Committees review concepts for clinical trials to control cancer symptoms and cancer treatment side effects, and concepts for studies of cancer care delivery.

  9. New steering mechanism for wheeled mobile robots

    Institute of Scientific and Technical Information of China (English)

    Sidibe Marie Bernard; FU Yi-li; XU He; MA Yu-lin

    2007-01-01

    A new castor wheel mechanism for omni-directional mobile platform is presented. A motion of translation is transformed into a rotation to steer the wheel with the help of a helical path fits into a translation joint and three rollers whose axes are connected to the driving shaft of the wheel. When the path moves in translation it acts on the rollers for steering. The path-roller friction transmission, the wheel kinematics and the maneuverability have been analyzed.

  10. Active steering control strategy for articulated vehicles

    Institute of Scientific and Technical Information of China (English)

    Kyong-il KIM; Hsin GUAN; Bo WANG; Rui GUO; Fan LIANG

    2016-01-01

    To improve maneuverability and stability of articulated vehicles, we design an active steering controller, including tractor and trailer controllers, based on linear quadratic regulator (LQR) theory. First, a three-degree-of-freedom (3-DOF) model of the tractor-trailer with steered trailer axles is built. The simulated annealing particle swarm optimization (SAPSO) algorithm is applied to identify the key parameters of the model under specified vehicle speed and steering wheel angle. Thus, the key pa-rameters of the simplified model can be obtained according to the vehicle conditions using an online look-up table and interpola-tion. Simulation results show that vehicle parameter outputs of the simplified model and TruckSim agree well, thus providing the ideal reference yaw rate for the controller. Then the active steering controller of the tractor and trailer based on LQR is designed to follow the desired yaw rate and minimize their side-slip angle of the center of gravity (CG) at the same time. Finally, simulation tests at both low speed and high speed are conducted based on the TruckSim-Simulink program. The results show significant effects on the active steering controller on improving maneuverability at low speed and lateral stability at high speed for the articulated vehicle. The control strategy is applicable for steering not only along gentle curves but also along sharp curves.

  11. Steerable beam systems for electron cyclotron resonance heating

    Energy Technology Data Exchange (ETDEWEB)

    Colborn, J.

    1985-08-31

    Several methods are discussed for steering a 200 kW pencil beam of electromagnetic waves in the 60 GHz to 200 GHz frequency range. These include methods incorporating swivelling mirrors, phased arrays, mode converters, and optical materials. It is found that for the near term, the mechanical systems are best, capable of steering times of 3 ms to 100 ms and losses of less than 5%. Optical methods, as yet virtually uninvestigated, appear to offer the only means of beam-steering in the 5..mu..s to 100..mu..s range necessary for MHD mode tracking.

  12. Improvement of motor inertia influence of electric power steering; Dendoshiki power steering no motor kansei no eikyo to hosho

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, S.; Sakamoto, K.; Hanamoto, Y. [Mazda Motor Corp., Hiroshima (Japan); Noritsugu, T. [Okayama University, Okayama (Japan)

    1997-10-01

    Motor inertia of electric power steering affects not only steering characteristics but vehicle dynamics. We have investigated the influence of motor inertia and proposed a feedback strategy to compensate it. Weight of the test vehicle is 1100Kg and the steering system is pinion type electric power steering. By using simulation model and vehicle test, we have realized natural steering maneuvering and stable vehicle dynamics. 4 refs., 11 figs.

  13. 延时效应对直线变压器电子束源的影响%Influence on linear transformer electron beam driver from delay effects

    Institute of Scientific and Technical Information of China (English)

    向飞; 谭杰; 王淦平

    2011-01-01

    The paper analyzes the reason why the pulse top spreads and the rise time shortens in a fault experiment on long pulse high power linear transformer microwave driver. Effects of waves superposition delay are discussed based on current transmission model. Output pulse waveforms are then derived by three dimensional simulation on the experimental prototype under excitations of different time sequences. The result suggests that, if the module closest to the diode is the first module physically, the delay from the switch triggered can be offsetted by waves superposition delay, and thus the wave optimization can be realized.%从长脉冲直线变压装置故障试验出发,对其波形顶部展宽、前沿变短现象进行了分析.利用电流传导理论,探讨了波叠加延迟效应.通过3维仿真分析,得到了不同时序激励的输出波形.结果表明:靠近二极管端单元为首模块时,开关触发延时与波叠加传输延迟可相互抵消,实现波形优化目标.

  14. Low-Absorption Liquid Crystals for Infrared Beam Steering

    Science.gov (United States)

    2013-10-22

    stirbar was dissolved 4-bromo-3- chloroiodobenzene (3.17 g, 10.0 mmol) in a mixture of 16 ml HiO and 40 ml 1,4-dioxane to give a colorless solution...The reaction was quenched with 40 ml HiO and the mixture was extracted with ether 100 ml twice. The organic portion was dried with MgSC>4, condensed

  15. Cluster beam steering onto silicon surfaces studied by molecular dynamics

    CERN Document Server

    Mazzone, A M

    2002-01-01

    The purpose of this study is to investigate the effects of the impact conditions on cluster deposition in silicon and is motivated by recent results obtained using a variable incidence angle during deposition of metallic clusters and atoms. Therefore deposition of silicon clusters with a kinetic energy in the range from 0.5 to 10 eV/atom directed at normal and grazing incidence onto crystalline silicon has been studied using a molecular dynamics simulation method. The influence of other relevant parameters, such as the interatomic forces and the cluster size and shape, has also been investigated. This study shows that the physics of deposition is almost entirely dictated by the nature of the interatomic forces. When using potentials with the four-fold coordination typical of bulk a clear dependence on the size N is observed and the spreading index eta decreases with the increase of N for all incidence conditions. The cluster binding strength is perceptibly increased when using a potential accounting for the c...

  16. Research on Modeling and Active Steering Control Algorithm for Electric Forklift Steer-by-Wire System

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-11-01

    Full Text Available In this paper, according to the structure characteristics of steer-by-wire (SBW system for the TFC20 electric forklift, steering dynamics model and two degree of freedom vehicle model are deduced for SBW forklift. Aiming at the free design features of the angular transmission characteristics in the SBW system of electric forklift, the theory of active steering control strategy is studied. After analyzing the influence factors of the angular trans mission ratio of the steering system, the ideal angular transmission ratio is proposed, which is based on the yaw rate gain invariance. Also, the control strategy of the yaw rate feedback and the full state feedback is studied. The simulation results show that the above strategy is effective for the active steering control; it can improve the operating stability and the response speed of the forklift.

  17. Digital Beam Deflectors Based Partly on Liquid Crystals

    Science.gov (United States)

    Pouch, John J.; Miranda, Felix A.; Kreminska, Liubov; Pishnyak, Oleg; Golovin, Andrii; Winker, Bruce K.

    2007-01-01

    A digital beam deflector based partly on liquid crystals has been demonstrated as a prototype of a class of optical beam-steering devices that contain no mechanical actuators or solid moving parts. Such beam-steering devices could be useful in a variety of applications, including free-space optical communications, switching in fiber-optic communications, general optical switching, and optical scanning. Liquid crystals are of special interest as active materials in nonmechanical beam steerers and deflectors because of their structural flexibility, low operating voltages, and the relatively low costs of fabrication of devices that contain them.

  18. Robustness of target dose coverage to motion uncertainties for scanned carbon ion beam tracking therapy of moving tumors.

    Science.gov (United States)

    Eley, John Gordon; Newhauser, Wayne David; Richter, Daniel; Lüchtenborg, Robert; Saito, Nami; Bert, Christoph

    2015-02-21

    Beam tracking with scanned carbon ion radiotherapy achieves highly conformal target dose by steering carbon pencil beams to follow moving tumors using real-time magnetic deflection and range modulation. The purpose of this study was to evaluate the robustness of target dose coverage from beam tracking in light of positional uncertainties of moving targets and beams. To accomplish this, we simulated beam tracking for moving targets in both water phantoms and a sample of lung cancer patients using a research treatment planning system. We modeled various deviations from perfect tracking that could arise due to uncertainty in organ motion and limited precision of a scanned ion beam tracking system. We also investigated the effects of interfractional changes in organ motion on target dose coverage by simulating a complete course of treatment using serial (weekly) 4DCTs from six lung cancer patients. For perfect tracking of moving targets, we found that target dose coverage was high ([Formula: see text] was 94.8% for phantoms and 94.3% for lung cancer patients, respectively) but sensitive to changes in the phase of respiration at the start of treatment and to the respiratory period. Phase delays in tracking the moving targets led to large degradation of target dose coverage (up to 22% drop for a 15° delay). Sensitivity to technical uncertainties in beam tracking delivery was minimal for a lung cancer case. However, interfractional changes in anatomy and organ motion led to large decreases in target dose coverage (target coverage dropped approximately 8% due to anatomy and motion changes after 1 week). Our findings provide a better understand of the importance of each of these uncertainties for beam tracking with scanned carbon ion therapy and can be used to inform the design of future scanned ion beam tracking systems.

  19. Robustness of target dose coverage to motion uncertainties for scanned carbon ion beam tracking therapy of moving tumors

    Science.gov (United States)

    Eley, John Gordon; Newhauser, Wayne David; Richter, Daniel; Lüchtenborg, Robert; Saito, Nami; Bert, Christoph

    2015-02-01

    Beam tracking with scanned carbon ion radiotherapy achieves highly conformal target dose by steering carbon pencil beams to follow moving tumors using real-time magnetic deflection and range modulation. The purpose of this study was to evaluate the robustness of target dose coverage from beam tracking in light of positional uncertainties of moving targets and beams. To accomplish this, we simulated beam tracking for moving targets in both water phantoms and a sample of lung cancer patients using a research treatment planning system. We modeled various deviations from perfect tracking that could arise due to uncertainty in organ motion and limited precision of a scanned ion beam tracking system. We also investigated the effects of interfractional changes in organ motion on target dose coverage by simulating a complete course of treatment using serial (weekly) 4DCTs from six lung cancer patients. For perfect tracking of moving targets, we found that target dose coverage was high ({{\\overline{V}}95} was 94.8% for phantoms and 94.3% for lung cancer patients, respectively) but sensitive to changes in the phase of respiration at the start of treatment and to the respiratory period. Phase delays in tracking the moving targets led to large degradation of target dose coverage (up to 22% drop for a 15° delay). Sensitivity to technical uncertainties in beam tracking delivery was minimal for a lung cancer case. However, interfractional changes in anatomy and organ motion led to large decreases in target dose coverage (target coverage dropped approximately 8% due to anatomy and motion changes after 1 week). Our findings provide a better understand of the importance of each of these uncertainties for beam tracking with scanned carbon ion therapy and can be used to inform the design of future scanned ion beam tracking systems.

  20. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition ...... mineral density) and psychological (e.g., low self-esteem) and underline the importance of careful clinical assessment of the patients.......Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition...

  1. No-cloning of quantum steering

    Science.gov (United States)

    Chiu, Ching-Yi; Lambert, Neill; Liao, Teh-Lu; Nori, Franco; Li, Che-Ming

    2016-06-01

    Einstein-Podolsky-Rosen (EPR) steering allows two parties to verify their entanglement, even if one party’s measurements are untrusted. This concept has not only provided new insights into the nature of non-local spatial correlations in quantum mechanics, but also serves as a resource for one-sided device-independent quantum information tasks. Here, we investigate how EPR steering behaves when one-half of a maximally entangled pair of qudits (multidimensional quantum systems) is cloned by a universal cloning machine. We find that EPR steering, as verified by a criterion based on the mutual information between qudits, can only be found in one of the copy subsystems but not both. We prove that this is also true for the single-system analogue of EPR steering. We find that this restriction, which we term ‘no-cloning of quantum steering’, elucidates the physical reason why steering can be used to secure sources and channels against cloning-based attacks when implementing quantum communication and quantum computation protocols.

  2. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  3. Research on Torque Ratio Based on the Steering Wheel Torque Characteristic for Steer-by-Wire System

    OpenAIRE

    Yandong Han; Lei He; Xiang Wang; Changfu Zong

    2014-01-01

    Steer-by-wire system can improve the performance of vehicle handling stability. Removing the mechanical linkages between the front wheels and the steering wheel leads to a key technique of force feedback for steer-by-wire system. In view of the characteristic of variable torque transmission ratio for steer-by-wire system, this paper proposes a method for designing torque ratio based on the steering wheel torque characteristic for steer-by-wire system. It converts the torque ratio design into ...

  4. Steering object-oriented computations with Python

    Energy Technology Data Exchange (ETDEWEB)

    Yang, T.-Y.B.; Dubois, P.F.; Furnish, G. [Lawrence Livermore National Lab., CA (United States); Beazley, D.M. [Utah Univ., Salt Lake City, UT (United States). Dept. of Computer Science

    1996-10-01

    We have described current approaches and future plans for steering C++ application, running Python on parallel platforms, and combination of Tk interface and Python interpreter in steering computations. In addition, there has been significant enhancement in the Gist module. Tk mega widgets has been implemented for a few physics applications. We have also written Python interface to SIJLO, a data storage package used as an interface to a visualization system named MeshTv. Python is being used to control large-scale simulations (molecular dynamics in particular) running on the CM-5 and T3D at LANL as well. A few other code development projects at LLNL are either using or considering Python as their steering shells. In summary, the merits of Python have been appreciated by more and more people in the scientific computation community.

  5. Stability analysis of automobile driver steering control

    Science.gov (United States)

    Allen, R. W.

    1981-01-01

    In steering an automobile, the driver must basically control the direction of the car's trajectory (heading angle) and the lateral deviation of the car relative to a delineated pathway. A previously published linear control model of driver steering behavior which is analyzed from a stability point of view is considered. A simple approximate expression for a stability parameter, phase margin, is derived in terms of various driver and vehicle control parameters, and boundaries for stability are discussed. A field test study is reviewed that includes the measurement of driver steering control parameters. Phase margins derived for a range of vehicle characteristics are found to be generally consistent with known adaptive properties of the human operator. The implications of these results are discussed in terms of driver adaptive behavior.

  6. Influence of different shoulder-elbow configurations on steering precision and steering velocity in automotive context.

    Science.gov (United States)

    Schmidt, Susanne; Seiberl, Wolfgang; Schwirtz, Ansgar

    2015-01-01

    Ergonomic design requirements are needed to develop optimum vehicle interfaces for the driver. The majority of the current specifications consider only anthropometric conditions and subjective evaluations of comfort. This paper examines specific biomechanical aspects to improve the current ergonomic requirements. Therefore, a research which involved 40 subjects was carried out to obtain more knowledge in the field of steering movement while driving a car. Five different shoulder-elbow joint configurations were analyzed using a driving simulator to find optimum posture for driving in respect of steering precision and steering velocity. Therefore, a 20 s precision test and a test to assess maximum steering velocity over a range of 90° steering motion have been conducted. The results show that driving precision, as well as maximum steering velocity, are significantly increased in mid-positions (elbow angles of 95° and 120°) compared to more flexed (70°) or extended (145° and 160°) postures. We conclude that driver safety can be enhanced by implementing these data in the automotive design process because faster and highly precise steering can be important during evasive actions and in accident situations. In addition, subjective comfort rating, analyzed with questionnaires, confirmed experimental results.

  7. Online optimized hysteresis-based steering feel model for steer-by-wire systems

    Directory of Open Access Journals (Sweden)

    Ahmet Kirli

    2016-06-01

    Full Text Available In rubber-wheeled road vehicles, the mechanical connection between steering wheel and front wheels provides steering-related feedback to the driver. The torque fed back to the driver through the steering linkages and steering wheel, which is called steering feel, helps the driver in controlling the vehicle. The torque feedback is reproduced via artificial methods in steer-by-wire systems due to the lack of mechanical connection. In this work, in order to minimize the physical workload and the lateral acceleration under the consideration of handling performance, optimization of a hysteresis-based steering feel has been studied. A 2-degree-of-freedom bicycle model based on the magic formula tire model has been used for simulations and hardware-in-the-loop experiments. A mathematical model is proposed in order to create an adaptive model-based optimization of the hysteresis parameters simultaneously while driving. A hardware-in-the-loop experimental setup has been used for the driving tests. The weave and the double-lane change tests have been performed with different drivers in order to demonstrate and quantify the optimization methods that are presented in this work.

  8. Steering disturbance rejection using a physics-based neuromusculoskeletal driver model

    Science.gov (United States)

    Mehrabi, Naser; Sharif Razavian, Reza; McPhee, John

    2015-10-01

    The aim of this work is to develop a comprehensive yet practical driver model to be used in studying driver-vehicle interactions. Drivers interact with their vehicle and the road through the steering wheel. This interaction forms a closed-loop coupled human-machine system, which influences the driver's steering feel and control performance. A hierarchical approach is proposed here to capture the complexity of the driver's neuromuscular dynamics and the central nervous system in the coordination of the driver's upper extremity activities, especially in the presence of external disturbance. The proposed motor control framework has three layers: the first (or the path planning) plans a desired vehicle trajectory and the required steering angles to perform the desired trajectory; the second (or the musculoskeletal controller) actuates the musculoskeletal arm to rotate the steering wheel accordingly; and the final layer ensures the precision control and disturbance rejection of the motor control units. The physics-based driver model presented here can also provide insights into vehicle control in relaxed and tensed driving conditions, which are simulated by adjusting the driver model parameters such as cognition delay and muscle co-contraction dynamics.

  9. Design and performance test of a two-axis fast steering mirror driven by piezoelectric actuators

    Science.gov (United States)

    Fang, Chu; Guo, Jin; Yang, Guo-qing; Jiang, Zhen-hua; Xu, Xin-hang; Wang, Ting-feng

    2016-09-01

    A novel design of a two-axis fast steering mirror (FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.

  10. Self accelerating electron Airy beams

    CERN Document Server

    Voloch-Bloch, Noa; Lilach, Yigal; Gover, Avraham; Arie, Ady

    2013-01-01

    We report the first experimental generation and observation of Airy beams of free electrons. The electron Airy beams are generated by diffraction of electrons through a nanoscale hologram, that imprints a cubic phase modulation on the beams' transverse plane. We observed the spatial evolution dynamics of an arc-shaped, self accelerating and shape preserving electron Airy beams. We directly observed the ability of electrons to self-heal, restoring their original shape after passing an obstacle. This electromagnetic method opens up new avenues for steering electrons, like their photonic counterparts, since their wave packets can be imprinted with arbitrary shapes or trajectories. Furthermore, these beams can be easily manipulated using magnetic or electric potentials. It is also possible to efficiently self mix narrow beams having opposite signs of acceleration, hence obtaining a new type of electron interferometer.

  11. Beam-Forming Concentrating Solar Thermal Array Power Systems

    Science.gov (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  12. A control theory approach to clock steering techniques.

    Science.gov (United States)

    Farina, Marcello; Galleani, Lorenzo; Tavella, Patrizia; Bittanti, Sergio

    2010-10-01

    Several clock and time scale steering methods have been developed according to different viewpoints by various time laboratories. By resorting to control theory ideas, we propose a common theoretical framework encompassing these methods. A comparison of the most common steering methodologies, namely, the classical steering approach, the GPS bang-bang method, and the linear quadratic Gaussian technique, is carried out. We believe that the use of control theory methods can potentially lead to a better understanding of clock steering algorithms.

  13. 46 CFR 58.25-20 - Piping for steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... actuating system including the reservoir. The storage tank must be permanently connected by piping so...

  14. 46 CFR 61.20-1 - Steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  15. 46 CFR 167.65-25 - Steering gear tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  16. 9 CFR 78.6 - Steers and spayed heifers.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Steers and spayed heifers. 78.6... Restrictions on Interstate Movement of Cattle Because of Brucellosis § 78.6 Steers and spayed heifers. Steers and spayed heifers may be moved interstate without restriction under this subpart....

  17. 9 CFR 78.21 - Bison steers and spayed heifers.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without restriction under this subpart....

  18. Working paper on public steering of privately owned sports facilities

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård

    This short paper discusses how municipalities can steer privately owned sports facilities. Firstly I analyse why steering of privately owned facilities is an interesting subject. Secondly I discuss what the advantages and drawbacks of using different approaches for steering sports facilities are....

  19. Doublet vs. FODO structure: beam dynamics and layout

    CERN Document Server

    Eshraqi, M; CERN. Geneva. BE Department

    2010-01-01

    A FoDo (singlet) structure is designed for the CERN Superconducting Proton LINAC. This architecture is compared to the baseline (doublet) architecture of SPL on the basis of its beam dynamics performance and the required investment. The sensitivity of both layouts to quadrupole gradient errors and misalignment is checked and a correction scheme for beam steering is proposed. Finally a single quad beam dilution scheme is studied and designed for the pilot beam dump.

  20. Parametrizable cameras for 3D computational steering

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van

    1997-01-01

    We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man

  1. Mass ratio from Doppler beaming and R{\\o}mer delay versus ellipsoidal modulation in the Kepler data of KOI-74

    CERN Document Server

    Bloemen, S; Degroote, P; Østensen, R H; Pápics, P I; Aerts, C; Koester, D; Gänsicke, B T; Breedt, E; Lombaert, R; Pyrzas, S; Copperwheat, C M; Exter, K; Raskin, G; Van Winckel, H; Prins, S; Pessemier, W; Frémat, Y; Hensberge, H; Jorissen, A; Van Eck, S

    2012-01-01

    We present a light curve analysis and radial velocity study of KOI-74, an eclipsing A star + white dwarf binary with a 5.2 day orbit. Aside from new spectroscopy covering the orbit of the system, we used 212 days of publicly available Kepler observations and present the first complete light curve fitting to these data, modelling the eclipses and transits, ellipsoidal modulation, reflection, and Doppler beaming. Markov Chain Monte Carlo simulations are used to determine the system parameters and uncertainty estimates. Our results are in agreement with earlier studies, except that we find an inclination of 87.0 \\pm 0.4\\degree, which is significantly lower than the previously published value. We find that the mass ratio derived from the radial velocity amplitude (q=0.104 \\pm 0.004) disagrees with that derived from the ellipsoidal modulation (q=0.052 \\pm 0.004} assuming corotation). This was found before, but with our smaller inclination, the discrepancy is even larger than previously reported. Accounting for the...

  2. Steered wheel for the support and/or steering of a vehicle, particularly hovercraft

    Energy Technology Data Exchange (ETDEWEB)

    Duell, H.J.; Kirchner, G.

    1977-04-07

    The invention concerns a steered wheel for the support or steering of a hovercraft, whose wheel suspension is provided with an eccentric journal for automatic setting in the direction of travel. So that the vehicle will not leave its track during changes of direction when the wheel is turned around the eccentric axis, according to the invention the wheel is supported on movable bearings at the journal in the direction of the driving axle.

  3. Beam dynamics design studies of a superconducting radioactive ion beam postaccelerator

    Directory of Open Access Journals (Sweden)

    M. A. Fraser

    2011-02-01

    Full Text Available The HIE-ISOLDE project at CERN proposes a superconducting upgrade to increase the energy range and quality of the radioactive ion beams produced at ISOLDE, which are currently postaccelerated by the normal conducting radioactive ion beam experiment linac. The specification and design choices for the HIE-ISOLDE linac are outlined along with a comprehensive beam dynamics study undertaken to understand and mitigate the sources of beam emittance dilution. The dominant cause of transverse emittance growth was attributed to the coupling between the transverse and longitudinal motions through the phase dependence of the rf defocusing force in the accelerating cavities. A parametric resonance induced by the coupling was observed and its excitation surveyed as a function of transverse phase advance using numerical simulations and analytic models to understand and avoid the regions of transverse beam instability. Other sources of emittance growth were studied and where necessary ameliorated, including the beam steering force in the quarter-wave resonator and the asymmetry of the rf defocusing forces in the solenoid focusing channel. A racetrack shaped beam port aperture was shown to improve the symmetry of the fields in the high-β quarter-wave resonator and reduce the loss of acceptance under the offset used to compensate the steering force. The methods used to compensate the beam steering are described and an optimization routine written to minimize the steering effect when all cavities of a given family are offset by the same amount, taking into account the different velocity profiles across the range of mass-to-charge states accepted. The assumptions made in the routine were shown to be adequate and the results well correlated with the beam quality simulated in multiparticle beam dynamics simulations. The specification of the design tolerances is outlined based on studies of the sensitivity of the beam to misalignment and errors, with particular

  4. Using Stars to Align a Steered Laser System for Cosmic Ray Simulation

    Science.gov (United States)

    Krantz, Harry; Wiencke, Lawrence

    2016-03-01

    Ultra high energy cosmic rays (UHECRs) are the highest energy cosmic particles with kinetic energy above 1018eV . UHECRs are detected from the air shower of secondary particles and UV florescence that results from interaction with the atmosphere. A high power UV laser beam can be used to simulate the optical signature of a UHCER air shower. The Global Light System (GLS) is a planned network of ground-based light sources including lasers to support the planned space-based Extreme Universe Space Observatory (EUSO). A portable prototype GLS laser station has been constructed at the Colorado School of Mines. Currently the laser system uses reference targets on the ground but stars can be used to better align the beam by providing a complete hemisphere of targets. In this work, a CCD camera is used to capture images of known stars through the steering head optics. The images are analyzed to find the steering head coordinates of the target star. The true coordinates of the star are calculated from the location and time of observation. A universal adjustment for the steering head is determined from the differences between the two pairs of coordinates across multiple stars. This laser system prototype will also be used for preflight tests of the ESUO Super Pressure Balloon mission.

  5. Infrared Risley beam pointer

    Science.gov (United States)

    Harford, Steven T.; Gutierrez, Homero; Newman, Michael; Pierce, Robert; Quakenbush, Tim; Wallace, John; Bornstein, Michael

    2014-03-01

    Ball Aerospace & Technologies Corp. (BATC) has developed a Risley Beam Pointer (RBP) mechanism capable of agile slewing, accurate pointing and high bandwidth. The RBP is comprised of two wedged prisms that offer a wide Field of Regard (FOR) and may be manufactured and operated with diffraction limited optical quality. The tightly packaged mechanism is capable of steering a 4 inch beam over a 60° half angle cone with better than 60 μrad precision. Absolute accuracy of the beam steering is better than 1 mrad. The conformal nature of the RBP makes it an ideal mechanism for use on low altitude aircraft and unmanned aerial vehicles. Unique aspects of the opto-mechanical design include i) thermal compliance to maintain bearing preload and optical figure over a wide temperature range; and ii) packaging of a remote infrared sensor that periodically reports the temperature of both prisms for accurate determination of the index of refraction. The pointing control system operates each prism independently and employs an inner rate loop nested within an outer position loop. Mathematics for the transformation between line-of-sight coordinates and prism rotation are hosted on a 200 MHz microcontroller with just 516 KB of RAM.

  6. Einstein-Podolsky-Rosen steering inequalities from entropic uncertainty relations

    Science.gov (United States)

    Schneeloch, James; Broadbent, Curtis J.; Walborn, Stephen P.; Cavalcanti, Eric G.; Howell, John C.

    2013-06-01

    We use entropic uncertainty relations to formulate inequalities that witness Einstein-Podolsky-Rosen (EPR)-steering correlations in diverse quantum systems. We then use these inequalities to formulate symmetric EPR-steering inequalities using the mutual information. We explore the differing natures of the correlations captured by one-way and symmetric steering inequalities and examine the possibility of exclusive one-way steerability in two-qubit states. Furthermore, we show that steering inequalities can be extended to generalized positive operator-valued measures, and we also derive hybrid steering inequalities between alternate degrees of freedom.

  7. How relativistic motion affects Einstein-Podolsky-Rosen steering

    Science.gov (United States)

    Sun, Wen-Yang; Wang, Dong; Ye, Liu

    2017-09-01

    In this letter, the dynamic behavior of Einstein-Podolsky-Rosen (EPR) steering and the redistribution of EPR steering under a relativistic framework are investigated. Specifically, we explore the scenario that particle A held by Alice is in a flat space-time and another particle B held by Bob entangled with A is in a non-inertial framework. The results show that EPR steering from Alice to Bob is dramatically destroyed by the Unruh effect caused by the acceleration of Bob. Besides, EPR steering possess asymmetry, and EPR steering asymmetry increases with growing intensity of the Unruh effect, implying that the Unruh effect can bring about EPR steering asymmetry. Furthermore, the reduced physically accessible EPR steering from Alice to Bob is distributed to the physically inaccessible EPR steering (from Alice to anti-Bob or from Bob to anti-Bob). Notably, unlike entanglement and quantum discord, only one of the EPR steering from Alice to anti-Bob and Bob to anti-Bob experiences a sudden birth with increase in the acceleration parameter, which means that they cannot simultaneously survive. That is, the monogamous relationship of EPR steering is still tenable in such a scenario. Consequently, we believe that EPR steering could also serve as an important information resource within long-distance quantum secure communication under the relativistic framework.

  8. Improving Einstein–Podolsky–Rosen steering inequalities with state information

    Energy Technology Data Exchange (ETDEWEB)

    Schneeloch, James [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Broadbent, Curtis J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Rochester Theory Center, University of Rochester, Rochester, NY 14627 (United States); Howell, John C. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

    2014-02-01

    We discuss the relationship between entropic Einstein–Podolsky–Rosen (EPR)-steering inequalities and their underlying uncertainty relations along with the hypothesis that improved uncertainty relations lead to tighter EPR-steering inequalities. In particular, we discuss how using information about the state of a quantum system affects one's ability to witness EPR-steering. As an example, we consider the recent improvement to the entropic uncertainty relation between pairs of discrete observables (Berta et al., 2010 [10]). By considering the assumptions that enter into the development of a steering inequality, we derive correct steering inequalities from these improved uncertainty relations and find that they are identical to ones already developed (Schneeloch et al., 2013 [9]). In addition, we consider how one can use state information to improve our ability to witness EPR-steering, and develop a new continuous variable symmetric EPR-steering inequality as a result.

  9. Active disturbance rejection control in steering by wire haptic systems.

    Science.gov (United States)

    Rodriguez-Angeles, A; Garcia-Antonio, J A

    2014-07-01

    This paper introduces a steering by wired haptic system based on disturbance rejection control techniques. High gain Generalized Proportional Integral (GPI) observers are considered for the estimation of tire and steering wheel dynamic disturbances. These disturbances are on line canceled to ensure tracking between the commanded steering wheel angle and the tire orientation angle. The estimated disturbances at the steering rack are feedback to the steering wheel to provide a haptic interface with the driver. The overall system behaves as a bilateral master-slave system. Very few sensors and minimum knowledge of the dynamic model are required. Experimental results are presented on a prototype platform that consists on: (1) half of the steering rack of a beetle VW vehicle, (2) a steering wheel.

  10. Improving Einstein-Podolsky-Rosen steering inequalities with state information

    Science.gov (United States)

    Schneeloch, James; Broadbent, Curtis J.; Howell, John C.

    2014-02-01

    We discuss the relationship between entropic Einstein-Podolsky-Rosen (EPR)-steering inequalities and their underlying uncertainty relations along with the hypothesis that improved uncertainty relations lead to tighter EPR-steering inequalities. In particular, we discuss how using information about the state of a quantum system affects one's ability to witness EPR-steering. As an example, we consider the recent improvement to the entropic uncertainty relation between pairs of discrete observables (Berta et al., 2010 [10]). By considering the assumptions that enter into the development of a steering inequality, we derive correct steering inequalities from these improved uncertainty relations and find that they are identical to ones already developed (Schneeloch et al., 2013 [9]). In addition, we consider how one can use state information to improve our ability to witness EPR-steering, and develop a new continuous variable symmetric EPR-steering inequality as a result.

  11. Fast-steering Mirror with Self-aligning ball bearing Supporting Structure

    Science.gov (United States)

    Xu, Xinhang; Wang, Bing; Han, Xudong

    2012-10-01

    A fast-steering mirror (FSM) with self-aligning ball bearing supporting structure was designed to accurately control the transmission direction of high-octane laser. First, linear voice coil actuators were selected and SiC mirror, rigid supporting structure, precise grating sensors for measuring mirror position were designed respectively on the basis of the fast-steering mirror working conditions and performing requirements. After finishing accurately manufacturing and assembling of mechanism parts, the servo control system was constituted, and then the designed FSM system was tested by experiments. The results showed that the FSM with self-aligning ball bearing supporting structure has not only great carrying capacity and resonance frequency, but it also has excellent angle stability (the stable precision of mirror is more than 2″). Furthermore, the FSM system has great adaptability to vibrancy, impact and rotation. Therefore, the designed FSM can satisfy application requirements of precise beam control system.

  12. Improvement of Steering Feel of Electric Power Steering System with Variable Gear Transmission System Using Decoupling Control

    Science.gov (United States)

    Morita, Yoshifumi; Yokoi, Akitoshi; Iwasaki, Makoto; Ukai, Hiroyuki; Matsui, Nobuyuki; Ito, Norihisa; Uryu, Nobuhiko; Mukai, Yasuhiko

    In this paper a new control method of Electric Power Steering (EPS) system with Variable Gear Transmission System (VGTS) is proposed. The control purpose is to achieve the desired steering gear ratio and the desired power assist with good steering feel. The basic idea of controller design is to apply decoupling control to this system and to separately design controllers for two decoupled systems. The angle control system and the torque control system are designed for the decoupled systems. In the angle control system the PID control is used for the desired gear ratio. In the torque control system the PID control is used for the desired assist torque designed so as to achieve good steering feel. In order to evaluate steering feel the Lissajous curve between the steering torque and steering angle is used. The effectiveness of the proposed controller is verified experimentally.

  13. Research on Torque Ratio Based on the Steering Wheel Torque Characteristic for Steer-by-Wire System

    Directory of Open Access Journals (Sweden)

    Yandong Han

    2014-01-01

    Full Text Available Steer-by-wire system can improve the performance of vehicle handling stability. Removing the mechanical linkages between the front wheels and the steering wheel leads to a key technique of force feedback for steer-by-wire system. In view of the characteristic of variable torque transmission ratio for steer-by-wire system, this paper proposes a method for designing torque ratio based on the steering wheel torque characteristic for steer-by-wire system. It converts the torque ratio design into equivalent assist torque design by analyzing their relationship. It achieves the torque ratio design at different conditions based on the negative equivalent assist torque characteristic curve. Simulations and vehicle experiments are conducted by the proposed method, and the results show that the design goal has been achieved and the steering wheel torque characteristic obtained is very similar to that of the reference car.

  14. Beam pattern improvement by compensating array nonuniformities in a guided wave phased array

    Science.gov (United States)

    Kwon, Hyu-Sang; Lee, Seung-Seok; Kim, Jin-Yeon

    2013-08-01

    This paper presents a simple data processing algorithm which can improve the performance of a uniform circular array based on guided wave transducers. The algorithm, being intended to be used with the delay-and-sum beamformer, effectively eliminates the effects of nonuniformities that can significantly degrade the beam pattern. Nonuniformities can arise intrinsically from the array geometry when the circular array is transformed to a linear array for beam steering and extrinsically from unequal conditions of transducers such as element-to-element variations of sensitivity and directivity. The effects of nonuniformities are compensated by appropriately imposing weight factors on the elements in the projected linear array. Different cases are simulated, where the improvements of the beam pattern, especially the level of the highest sidelobe, are clearly seen, and related issues are discussed. An experiment is performed which uses A0 mode Lamb waves in a steel plate, to demonstrate the usefulness of the proposed method. The discrepancy between theoretical and experimental beam patterns is explained by accounting for near-field effects.

  15. Influence of steering effects on strain detection in AlGaInN/GaN heterostructures by ion channelling

    Energy Technology Data Exchange (ETDEWEB)

    Redondo-Cubero, A; Fernandez-Garrido, S; Munoz, E; Calleja, E [ISOM and DIE, ETSI Telecomunicacion, Universidad Politecnica de Madrid, E-28040 Madrid (Spain); Lorenz, K; Franco, N; Alves, E [Instituto Tecnologico e Nuclear, Estrada nacional 10, 2686-953 Sacavem (Portugal); Gago, R [Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Smulders, P J M, E-mail: andres.redondo@uam.e [Nuclear Solid State Physics, Materials Science Centre, Groningen University, Nijenborgh 4, 9747 AG Groningen (Netherlands)

    2009-03-21

    Ion steering effects in the interface of heterostructures can strongly influence the shape and position of angular channelling scans leading to considerable error in the determination of strain by ion channelling. As an example, this paper presents channelling measurements on a near-lattice-matched AlGaInN/GaN heterostructure which show no shift between the angular scans from the quaternary layer and the underlying GaN substrate although high resolution x-ray diffraction data confirm the presence of strain in the layer. Such 'anomalous' behaviour was studied by means of Monte Carlo simulations for nitride ternary and quaternary films in the whole composition range. The simulations show that the thickness, magnitude of the distortion of the strained lattice and energy of the probing beam are critical parameters controlling the impact of steering. Three composition/strain regions were established for a typical beam of 2 MeV alpha particles corresponding to different intensities of the steering potential and in which strain measurements by ion channelling are (a) correct, (b) possible but require corrections and (c) not possible due to steering effects.

  16. Conditional steering under the von Neumann scenario

    Science.gov (United States)

    Mukherjee, Kaushiki; Paul, Biswajit; Karmakar, Sumana; Sarkar, Debasis; Mukherjee, Amit; Bhattacharya, Some Sankar; Roy, Arup

    2017-08-01

    In Phys. Lett. A 166, 293 (1992), 10.1016/0375-9601(92)90711-T, Popescu and Rohrlich characterized nonlocality of pure n -partite entangled systems by studying bipartite violation of local realism when n -2 number of parties perform projective measurements on their particles. A pertinent question in this scenario is whether similar characterization is possible for n -partite mixed entangled states also. In the present work we have followed an analogous approach so as to explore whether given a tripartite mixed entangled state the conditional bipartite states obtained by performing projective measurement on the third party demonstrate a weaker form of nonlocality, quantum steering. We also compare this phenomenon of conditional steering with existing notions of tripartite correlations.

  17. ACTIVE FRONT STEERING DURING BRAKING PROCESS

    Institute of Scientific and Technical Information of China (English)

    CHEN Deling; CHEN Li; YIN Chengliang; ZHANG Yong

    2008-01-01

    An active front steering (AFS) intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation (HILS) system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.

  18. Boundaries can steer active Janus spheres

    Science.gov (United States)

    Das, Sambeeta; Garg, Astha; Campbell, Andrew I.; Howse, Jonathan; Sen, Ayusman; Velegol, Darrell; Golestanian, Ramin; Ebbens, Stephen J.

    2015-12-01

    The advent of autonomous self-propulsion has instigated research towards making colloidal machines that can deliver mechanical work in the form of transport, and other functions such as sensing and cleaning. While much progress has been made in the last 10 years on various mechanisms to generate self-propulsion, the ability to steer self-propelled colloidal devices has so far been much more limited. A critical barrier in increasing the impact of such motors is in directing their motion against the Brownian rotation, which randomizes particle orientations. In this context, here we report directed motion of a specific class of catalytic motors when moving in close proximity to solid surfaces. This is achieved through active quenching of their Brownian rotation by constraining it in a rotational well, caused not by equilibrium, but by hydrodynamic effects. We demonstrate how combining these geometric constraints can be utilized to steer these active colloids along arbitrary trajectories.

  19. Self-testing through EPR-steering

    Science.gov (United States)

    Šupić, Ivan; Hoban, Matty J.

    2016-07-01

    The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system.

  20. TRANSFERRING OF MOVEMENT FOR STEERING EQUIPMENT

    OpenAIRE

    Outhier, Maxime; Rydström, Vilhelm; Sanz, Imanol

    2001-01-01

    This Examination Thesis was done at the Blekinge Institute of Technology of Karlskrona. The work is a part of the education to Bachelor of Science in product development. The task consists of changing the steering wheel transmission of the DYNAPAC CA soil compactor machine made by Svedala Compaction Equipment AB. During the work we have followed the Fredy Olsson product development method. The work is divided in two parts: The Concept phase and The Primary Construction phase. In the Concept p...

  1. On the Feasibility of Dynamic Power Steering

    Energy Technology Data Exchange (ETDEWEB)

    Barker, Kevin J.; Kerbyson, Darren J.; Anger, Eric A.

    2014-11-16

    While high performance has always been the primary constraint behind large-scale system design, future systems will be built with increasing energy efficiency in mind. Mechanisms such as fine-grained power scaling and gating will provide tools to system-software and application developers to ensure the most efficient use of tightly constrained power budgets. Such approaches to-date have been focused on node level optimizations to impact overall system energy efficiency. In this work we introduce Dynamic Power Steering, in which power can be dynamically routed across a system to resources where it will be of most benefit and away from other resources to maintain a near-constant overall power budget. This, a higher level algorithmic approach to improving energy efficiency, considers the whole extent of a system being used by an application. It can be used for applications in which there is load imbalance that varies over its execution. Using two classes of applications, namely those that contain a wave front type processing, and a particle-in-cell, we quantify the benefit of Dynamic Power Steering for a variety of workload characteristics and derive some insight into the ways in which workload behavior affect Power Steering applicability.

  2. Spatial-domain interactions between ultra-weak optical beams

    CERN Document Server

    Khadka, Utsab; Xiao, Min

    2013-01-01

    We have observed the spatial interactions between two ultra-weak optical beams that are initially collinear and non-overlapping. The weak beams are steered towards each other by a spatially varying cross-Kerr refractive index waveguide written by a strong laser beam in a three-level atomic medium utilizing quantum coherence. After being brought together, the weak beams show controllable phase-dependent outcomes. This is the first observation of soliton-like interactions between weak beams and can be useful for all-optically tunable beam-combining, switching and gates for weak photonic signals.

  3. Comparison of manual steering and steering via joystick of a flexible rhino endoscope.

    Science.gov (United States)

    Eckl, R; Gumprecht, J J; Strauss, G; Hofer, M; Dietz, A; Lueth, T C

    2010-01-01

    Flexible endoscopes are used in ENT surgery for examination tasks in cases wherever rigid endoscopes are unsuitable to reach certain positions in the nasal cavity. Until today they are steered by hand and no robotized system has been put into clinical practice. One qualification a robot manipulator system has to fulfill to be accepted is not to create new disadvantages compared to the conventional method in surgery. An important factor is the time needed to steer the new system compared to the time needed to steer the conventional system. In this article a robot manipulator system and an experiment are presented to compare the particular times test persons need to perform a certain task. This approach offers the possibility to benchmark the developed robot manipulator system and future systems for flexible rhino endoscopes.

  4. Modeling the radiation of ultrasonic phased-array transducers with Gaussian beams.

    Science.gov (United States)

    Huang, Ruiju; Schmerr, Lester W; Sedov, Alexander

    2008-12-01

    A new transducer beam model, called a multi-Gaussian array beam model, is developed to simulate the wave fields radiated by ultrasonic phased-array transducers. This new model overcomes the restrictions on using ordinary multi-Gaussian beam models developed for large single-element transducers in phased-array applications. It is demonstrated that this new beam model can effectively model the steered and focused beams of a linear phased-array transducer.

  5. Fault-tolerant Actuator System for Electrical Steering of Vehicles

    DEFF Research Database (Denmark)

    Sørensen, Jesper Sandberg; Blanke, Mogens

    2006-01-01

    Being critical to the safety of vehicles, the steering system is required to maintain the vehicles ability to steer until it is brought to halt, should a fault occur. With electrical steering becoming a cost-effective candidate for electrical powered vehicles, a fault-tolerant architecture...... is needed that meets this requirement. This paper studies the fault-tolerance properties of an electrical steering system. It presents a fault-tolerant architecture where a dedicated AC motor design used in conjunction with cheap voltage measurements can ensure detection of all relevant faults...... in the steering system. The paper shows how active control reconfiguration can accommodate all critical faults. The fault-tolerant abilities of the steering system are demonstrated on the hardware of a warehouse truck....

  6. Gaussian quantum steering and its asymmetry in curved spacetime

    CERN Document Server

    Wang, Jieci; Jing, Jiliang; Fan, Heng

    2015-01-01

    We study Gaussian quantum steering and its asymmetry in the background of a Schwarzschild black hole. We present a Gaussian channel description of quantum state evolution under the influence of Hawking radiation. We find that thermal noise introduced by Hawking effect will destroy the steerability between an inertial observer Alice and an accelerated observer Bob who hovers outside an event horizon, while it generates steerability between Bob and a hypothetical observer Anti-Bob inside the event horizon. Besides, unlike entanglement behaviors in curved spacetime, here the steering from Alice to Bob suffers from a ``sudden death" and the steering from Anti-Bob to Bob appears a ``sudden birth" with the increasing of Hawking temperature. We also find that the Gaussian steering is always asymmetric and the maximum steering asymmetry can \\emph{ exceed} $\\ln 2$ in curved spacetime, which is quite different from the flat spacetime case [Phys. Rev. Lett. 114, 060403 (2015)] where the steering asymmetry can \\emph{neve...

  7. Multipartite Gaussian steering: monogamy constraints and cryptographical applications

    CERN Document Server

    Xiang, Yu; Adesso, Gerardo; He, Qiongyi

    2016-01-01

    We derive laws for the distribution of quantum steering among different parties in multipartite Gaussian states under Gaussian measurements. We prove that a monogamy relation akin to the generalized Coffman-Kundu-Wootters inequality holds quantitatively for a recently introduced measure of Gaussian steering. We then define the residual Gaussian steering, stemming from the monogamy inequality, as an indicator of collective steering-type correlations. For pure three-mode Gaussian states, the residual acts a quantifier of genuine multipartite steering, and is interpreted operationally in terms of the guaranteed key rate in the task of secure quantum secret sharing. Optimal resource states for the latter protocol are identified, and their possible experimental implementation discussed. Our results pin down the role of multipartite steering for quantum communication.

  8. STUDY ON FUZZY SELF-LEARNING CONTROL SYSTEM FOR SHIP STEERING

    Institute of Scientific and Technical Information of China (English)

    LIU Qing; WU Xiu-heng; ZOU Zao-jian

    2004-01-01

    Fuzzy control has shown success in some application areas and emerged as an alternative to some conventional control schemes. There are also some drawbacks in this approach, for example it is hard to justify the choice of fuzzy controller parameters and control rules, and control precision is low, and so on. Fuzzy control is developing towards self-learning and adaptive. The ship steering motion is a nonlinear, coupling, time-delay complicated system. How to control it effectively is the problem that many scholars are studying. In this paper, based on the repeated control of the robot, the self-learning arithmetic was worked out. The arithmetic was realized in fuzzy logic way and used in cargo steering. It is the first time for the arithmetic to be used in cargo steering. Our simulation results show that the arithmetic is effective and has several potential advantages over conventional fuzzy control.This work lays a foundation in modeling and analyzing the fuzzy learning control system.

  9. Feedback control of optical beam spatial profiles using thermal lensing

    CERN Document Server

    Liu, Zhanwei; Arain, Muzammil A; Williams, Luke; Mueller, Guido; Tanner, David B; Reitze, David H

    2013-01-01

    A method for active control of the spatial profile of a laser beam using adaptive thermal lensing is described. A segmented electrical heater was used to generate thermal gradients across a transmissive optical element, resulting in a controllable thermal lens. The segmented heater also allows the generation of cylindrical lenses, and provides the capability to steer the beam in both horizontal and vertical planes. Using this device as an actuator, a feedback control loop was developed to stabilize the beam size and position.

  10. Multi-axle dynamic steering system of truck-howitzer

    Institute of Scientific and Technical Information of China (English)

    Yanliang LI; Xiuhua GAO; Chunqiu ZHANG; Yubo SUN

    2008-01-01

    A two-degree-of-freedom (2-DOF) steering model of multi-axle vehicle was established. The steering center position, the relationship between the steering angle and the vehicle velocity, and the minimum turn radius were deduced on the basis of the proportional control with a zero sideslip angle. Results indicate that the system stability is decided by the vehicle barycenter position and the lateral stiffness of a tire. Under this control, the steady value of the lateral acceleration is obviously diminished and the yaw angular velocity changes little under any vehicle velocity. The system rapidly responds, the vehicle smoothly steers, and its handling stability is prominently improved.

  11. Analysis of Vehicle Steering and Driving Bifurcation Characteristics

    Directory of Open Access Journals (Sweden)

    Xianbin Wang

    2015-01-01

    Full Text Available The typical method of vehicle steering bifurcation analysis is based on the nonlinear autonomous vehicle model deriving from the classic two degrees of freedom (2DOF linear vehicle model. This method usually neglects the driving effect on steering bifurcation characteristics. However, in the steering and driving combined conditions, the tyre under different driving conditions can provide different lateral force. The steering bifurcation mechanism without the driving effect is not able to fully reveal the vehicle steering and driving bifurcation characteristics. Aiming at the aforementioned problem, this paper analyzed the vehicle steering and driving bifurcation characteristics with the consideration of driving effect. Based on the 5DOF vehicle system dynamics model with the consideration of driving effect, the 7DOF autonomous system model was established. The vehicle steering and driving bifurcation dynamic characteristics were analyzed with different driving mode and driving torque. Taking the front-wheel-drive system as an example, the dynamic evolution process of steering and driving bifurcation was analyzed by phase space, system state variables, power spectral density, and Lyapunov index. The numerical recognition results of chaos were also provided. The research results show that the driving mode and driving torque have the obvious effect on steering and driving bifurcation characteristics.

  12. Predicting water intake by yearling feedlot steers.

    Science.gov (United States)

    Sexson, J L; Wagner, J J; Engle, T E; Eickhoff, J

    2012-06-01

    Data from 4 separate beef cattle feedlot experiments, which were conducted at the Southeast Colorado Research Center (SECRC) in Lamar, CO, in 2001, 2003, 2004, and 2007, were utilized in a retrospective longitudinal study investigating possible relationships between daily water consumption (WC), DMI, and weather variables. The data set consisted of 8,209 records from 2001, 2003, 2004, and 2007, with pen based daily WC (L•animal(-1)) and DMI measurements and calculated daily steer BW from April to October in each year. Daily weather data were obtained from the weather station located at Lamar Municipal Airport located approximately 1.9 km from SECRC. Data collected consisted of daily high, low, and mean temperature; high, low, and mean humidity; high, low, and mean sea level pressure; mean wind speed; total precipitation; and average daily wind direction (cosine of radians from due north). Univariate analysis demonstrated that the continuous variables of BW, humidity, and sea level pressure were negatively related (P high temperature squared, high humidity squared, low temperature, low temperature squared, low humidity, average sea level pressure, average wind speed, average daily BW, high sea level pressure, low sea level pressure, high humidity, and low humidity. The generalized R(2) of the parsimonious multivariate model was 0.32. These results indicate that BW and numerous weather factors are related to WC by yearling feedlot steers. Dry matter intake had minimal impact on WC for yearling feedlot steers consuming steam-flaked corn-based high concentrate diets from mid-spring to early fall.

  13. Einstein-Podolsky-Rosen steering and quantum steering ellipsoids: Optimal two-qubit states and projective measurements

    Science.gov (United States)

    McCloskey, R.; Ferraro, A.; Paternostro, M.

    2017-01-01

    We identify the families of states that maximize some recently proposed quantifiers of Einstein-Podolsky-Rosen (EPR) steering and the volume of the quantum steering ellipsoid (QSE). The optimal measurements which maximize genuine EPR steering measures are discussed and we develop a way to find them using the QSE. We thus explore the links between genuine EPR steering and the QSE and introduce states that can be the most useful for one-sided device-independent quantum cryptography for a given amount of noise.

  14. Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

    Directory of Open Access Journals (Sweden)

    Pingxia Zhang

    2016-05-01

    Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

  15. Stress indicators in steers at slaughtering

    Directory of Open Access Journals (Sweden)

    A. Zarrilli

    2010-04-01

    Full Text Available This work aimed to assess the blood modifications of some slaughtering-linked stress hormones in cattle subject to butcher standardized procedures. The blood samples of 20 Limousine 12-13 months old steers have been collected before slaughtering, during lairage, and after stunning by captive bolt gun, during exsanguination. The plasma level of epinephrine, norepinephrine, cortisol and beta-endorphin have been assayed by EIA. The data indicate that catecholamines, cortisol and beta-endorphin did not significantly increase after stunning in these animals.

  16. Beam instability in 980-nm power lasers: Experiment and analysis

    Science.gov (United States)

    Guthrie, James; Tan, G. L.; Ohkubo, M.; Fukushima, T.; Ikegami, Y.; Ijichi, T.; Irikawa, M.; Mand, R. S.; Xu, J. M.

    1994-12-01

    A theoretical analysis of beam instability (steering), commonly observed in high power ridge waveguide laser diodes is presented. A physical model of multiple interfering lateral modes is proposed and implemented in a two-dimensional self-consistent numerical code. It is shown that the dynamic evolution of the effective waveguide and the coherent lasing of emergent multiple lateral modes of the waveguide under high injection could lead to beam steering and knees in the fiber coupled L-I characteristics. The theory of simultaneous lasing and interaction between several lateral modes is found to be consistent with the observed back-plane radiation image.

  17. Nonparaxial multi-Gaussian beam models and measurement models for phased array transducers.

    Science.gov (United States)

    Zhao, Xinyu; Gang, Tie

    2009-01-01

    A nonparaxial multi-Gaussian beam model is proposed in order to overcome the limitation that paraxial Gaussian beam models lose accuracy in simulating the beam steering behavior of phased array transducers. Using this nonparaxial multi-Gaussian beam model, the focusing and steering sound fields generated by an ultrasonic linear phased array transducer are calculated and compared with the corresponding results obtained by paraxial multi-Gaussian beam model and more exact Rayleigh-Sommerfeld integral model. In addition, with help of this novel nonparaxial method, an ultrasonic measurement model is provided to investigate the sensitivity of linear phased array transducers versus steering angles. Also the comparisons of model predictions with experimental results are presented to certify the accuracy of this provided measurement model.

  18. Internal models direct dragonfly interception steering.

    Science.gov (United States)

    Mischiati, Matteo; Lin, Huai-Ti; Herold, Paul; Imler, Elliot; Olberg, Robert; Leonardo, Anthony

    2015-01-15

    Sensorimotor control in vertebrates relies on internal models. When extending an arm to reach for an object, the brain uses predictive models of both limb dynamics and target properties. Whether invertebrates use such models remains unclear. Here we examine to what extent prey interception by dragonflies (Plathemis lydia), a behaviour analogous to targeted reaching, requires internal models. By simultaneously tracking the position and orientation of a dragonfly's head and body during flight, we provide evidence that interception steering is driven by forward and inverse models of dragonfly body dynamics and by models of prey motion. Predictive rotations of the dragonfly's head continuously track the prey's angular position. The head-body angles established by prey tracking appear to guide systematic rotations of the dragonfly's body to align it with the prey's flight path. Model-driven control thus underlies the bulk of interception steering manoeuvres, while vision is used for reactions to unexpected prey movements. These findings illuminate the computational sophistication with which insects construct behaviour.

  19. Optimization Under Uncertainty for Wake Steering Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Annoni, Jennifer [National Renewable Energy Laboratory (NREL), Golden, CO (United States); King, Ryan N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fleming, Paul A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ning, Andrew [Brigham Young University

    2017-08-03

    Offsetting turbines' yaw orientations from incoming wind is a powerful tool that may be leveraged to reduce undesirable wake effects on downstream turbines. First, we examine a simple two-turbine case to gain intuition as to how inflow direction uncertainty affects the optimal solution. The turbines are modeled with unidirectional inflow such that one turbine directly wakes the other, using ten rotor diameter spacing. We perform optimization under uncertainty (OUU) via a parameter sweep of the front turbine. The OUU solution generally prefers less steering. We then do this optimization for a 60-turbine wind farm with unidirectional inflow, varying the degree of inflow uncertainty and approaching this OUU problem by nesting a polynomial chaos expansion uncertainty quantification routine within an outer optimization. We examined how different levels of uncertainty in the inflow direction effect the ratio of the expected values of deterministic and OUU solutions for steering strategies in the large wind farm, assuming the directional uncertainty used to reach said OUU solution (this ratio is defined as the value of the stochastic solution or VSS).

  20. The effect of varying path properties in path steering tasks

    NARCIS (Netherlands)

    Liu, L.; Liere, R. van

    2010-01-01

    Path steering is a primitive 3D interaction task that requires the user to navigate through a path of a given length and width. In a previous paper, we have conducted controlled experiments in which users operated a pen input device to steer a cursor through a 3D path subject to fixed path propertie

  1. Robotic needle steering: design, modeling, planning, and image guidance

    NARCIS (Netherlands)

    Cowan, Noah J.; Goldberg, Ken; Chirikjian, Gregory S.; Fichtinger, Gabor; Alterovitz, Ron; Reed, Kyle B.; Kallem, Vinutha; Park, Wooram; Misra, Sarthak; Okamura, Allison M.; Rosen, Jacob; Hannaford, Blake; Satava, Richard M.

    2010-01-01

    This chapter describes how advances in needle design, modeling, planning, and image guidance make it possible to steer flexible needles from outside the body to reach specified anatomical targets not accessible using traditional needle insertion methods. Steering can be achieved using a variety of m

  2. 3D computational steering with parametrized geometric objects

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van

    1996-01-01

    Computational Steering is the ultimate goal of interactive simulation: researchers change parameters of their simulation and immediately receive feedback on the effect. We present a general and flexible graphics tool that is part of an environment for Computational Steering developed at CWI. It enab

  3. Gaussian quantum steering and its asymmetry in curved spacetime

    Science.gov (United States)

    Wang, Jieci; Cao, Haixin; Jing, Jiliang; Fan, Heng

    2016-06-01

    We study Gaussian quantum steering and its asymmetry in the background of a Schwarzschild black hole. We present a Gaussian channel description of quantum state evolution under the influence of Hawking radiation. We find that thermal noise introduced by the Hawking effect will destroy the steerability between an inertial observer Alice and an accelerated observer Bob who hovers outside the event horizon, while it generates steerability between Bob and a hypothetical observer anti-Bob inside the event horizon. Unlike entanglement behaviors in curved spacetime, here the steering from Alice to Bob suffers from a "sudden death" and the steering from anti-Bob to Bob experiences a "sudden birth" with increasing Hawking temperature. We also find that the Gaussian steering is always asymmetric and the maximum steering asymmetry cannot exceed ln 2 , which means the state never evolves to an extremal asymmetry state. Furthermore, we obtain the parameter settings that maximize steering asymmetry and find that (i) s =arccosh cosh/2r 1 -sinh2r is the critical point of steering asymmetry and (ii) the attainment of maximal steering asymmetry indicates the transition between one-way steerability and both-way steerability for the two-mode Gaussian state under the influence of Hawking radiation.

  4. The impact of force feedback level on steering performance

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.H.

    2013-01-01

    Steer-by-wire systems provide designers the ability to customize and personalize force feedback on the steering wheel, based on individual preferences. Earlier studies using subjective responses have shown that there are individual differences in preferences for force feedback. It has also been foun

  5. High-index-contrast grating reflector with beam steering ability for the transmitted beam.

    Science.gov (United States)

    Carletti, Luca; Malureanu, Radu; Mørk, Jesper; Chung, Il-Sug

    2011-11-07

    High-index contrast grating mirrors providing wave front control of the transmitted light as well as high reflectivity over a broad bandwidth are suggested and both numerically and experimentally investigated. General design rules to engineer these structures for different applications are derived. Such grating mirrors would have a significant impact on low cost laser fabrication, since a more efficient integration of optoelectronic modules can be achieved by avoiding expensive external lens systems.

  6. High-index-contrast grating reflector with beam steering ability for the transmitted beam

    DEFF Research Database (Denmark)

    Carletti, Luca; Malureanu, Radu; Mørk, Jesper

    2011-01-01

    High-index contrast grating mirrors providing wave front control of the transmitted light as well as high reflectivity over a broad bandwidth are suggested and both numerically and experimentally investigated. General design rules to engineer these structures for different applications are derived...

  7. Linear systems analysis of the ciliary steering behavior associated with negative-phototaxis in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Josef, Keith; Saranak, Jureepan; Foster, Kenneth W

    2006-12-01

    In response to light stimulation Chlamydomonas reinhardtii changes the beating frequency, beating pattern, and beating synchrony of the trans and cis cilia to steer the freely-swimming cell relative to light sources. To understand the cell steering behavior the impulse responses of the beating frequency and stroke velocity of each cilium have been obtained with high temporal resolution on cells held with a micropipette. Interestingly the response of each cilium is quite different. The trans cilium responds with less delay than the cis cilium for both beating frequency and stroke velocity. For light stimulation at 2 Hz, the critical cell-rotation frequency, both responses of the trans and cis cilia are about 180 degrees out of phase. The trans-cilium beating frequency response peaks at a stimulus frequency of 5-6 Hz, higher than the cis at 1-2 Hz. The stroke velocities of the trans and cis cilia have the same stimulus-frequency response (2 Hz), but the trans cilium has a shorter delay than the cis. The times to maximum response are much shorter than the time for a rotation of the cell. The use of two different approaches that enable the trans cilium to respond ahead of the cis for both the beating frequency and stroke velocity responses suggests the importance of both responses to phototaxis. Internal cell processing responsible for the time course of the responses is proposed.

  8. Experimental Study on Antivibration Control of Electrical Power Steering Systems

    Directory of Open Access Journals (Sweden)

    Zhaojian Wang

    2014-01-01

    Full Text Available We focus on the antivibration controller design problem for electrical power steering (EPS systems. The EPS system has significant advantages over the traditional hydraulic steering system. However, the improper motor controller design would lead to the steering wheel vibration. Therefore, it is necessary to investigate the antivibration control strategy. For the implementation study, we also present the motor driver design and the software design which is used to monitor the sensors and the control signal. Based on the investigation on the regular assistant algorithm, we summarize the difficulties and problems encountered by the regular algorithm. After that, in order to improve the performance of antivibration and the human-like steering feeling, we propose a new assistant strategy for the EPS. The experiment results of the bench test illustrate the effectiveness and flexibility of the proposed control strategy. Compared with the regular controller, the proposed antivibration control reduces the vibration of the steering wheel a lot.

  9. Sidelobe Suppression with Null Steering by Independent Weight Control

    Directory of Open Access Journals (Sweden)

    Zafar-Ullah Khan

    2015-01-01

    Full Text Available A uniform linear array of n antenna elements can steer up to n-1 nulls. In situations where less than n-1 nulls are required to be steered, the existing algorithms have no criterion to utilize the remaining weights for sidelobe suppression. This work combines sidelobe suppression capability with null steering by independent weight control. For this purpose, the array factor is transformed as the product of two polynomials. One of the polynomials is used for null steering by independent weight control, while the second one is for sidelobe suppression whose coefficients or weights are determined by using convex optimization. Finally, a new structure is proposed to incorporate the product of two polynomials such that sidelobe suppression weights are decoupled from those of null steering weights. Simulation results validate the effectiveness of the proposed scheme.

  10. Conclusive quantum steering with superconducting transition edge sensors

    CERN Document Server

    Smith, Devin H; de Almeida, Marcelo; Branciard, Cyril; Fedrizzi, Alessandro; Weinhold, Till J; Lita, Adriana; Calkins, Brice; Gerrits, Thomas; Nam, Sae Woo; White, Andrew G

    2011-01-01

    Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices to cheat by hiding unfavorable events in losses. Here we close this "detection loophole" by combining a highly efficient source of entangled photon pairs with superconducting transition edge sensors. We achieve an unprecedented $\\sim$62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 standard deviations. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.

  11. Study on classification and identification methods of driver steering characteristics

    Directory of Open Access Journals (Sweden)

    Gang LI

    2015-12-01

    Full Text Available Aiming at the vehicle driver's steering characteristic classification and identification, the research method is initially explored based on CarSim simulation platform. The simulation experiment of steering condition is designed and the test data is collected. According to the maximum yaw rate of the vehicle, the driver steering characteristics are classified by K-means clustering algorithm. The driver steering characteristics identification models are established by learning vector quantization (LVQ neural network, BP neural network, and support vector machine (SVM respectively in the environment of Matlab software. The test experiment and comparison are done for the three kinds of approaches, and the results show that all those three kinds of identification approaches have high accuracy, and the SVM method has a certain advantage on driver steering characteristics identification.

  12. Autonomous learning by simple dynamical systems with delayed feedback.

    Science.gov (United States)

    Kaluza, Pablo; Mikhailov, Alexander S

    2014-09-01

    A general scheme for the construction of dynamical systems able to learn generation of the desired kinds of dynamics through adjustment of their internal structure is proposed. The scheme involves intrinsic time-delayed feedback to steer the dynamics towards the target performance. As an example, a system of coupled phase oscillators, which can, by changing the weights of connections between its elements, evolve to a dynamical state with the prescribed (low or high) synchronization level, is considered and investigated.

  13. Partial Alignment for Improvement of Beam Transmission at KOMAC

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Dong-Hyuk; Kim, Dae-Il; Ahn, Tae-Sung; Kim, Han-Sung; Kwon, Hyeok-Jung; Cho, Yong-Sub [KOMAC, Gyeongju (Korea, Republic of)

    2015-05-15

    The ion source and steering magnets were aligned for improving the beam transmission. It is expected that the re-alignment of accelerator components can reduce the beam loss which can occur for the dislocation among them. The center displacements of RFQ and 20MeV DTL are different to 100MeV DTL, so it is necessary to re-align in next maintenance period. 100MeV proton linac placed in KOMAC (Korea Multi-purpose Accelerator Complex) has been operated and provided to beam users. There are two maintenance periods every year, winter (Jan-Feb) and summer (Jul-Aug). In maintenance period, proton linac is re-aligned for the improvement of beam transmission. 4 newly steering magnet are installed in beam line. To align the steering magnet, network align in tunnel is measured using by laser tracker. In addition, the position of ion source is away from the position of RFQ in the result of the survey of network align. The alignment of steering magnet after installation is performed. At the same time, the position of accelerator component is checked and aligned partially.

  14. Experimental delayed-choice entanglement swapping

    Science.gov (United States)

    Ma, Xiao-Song; Zotter, Stefan; Kofler, Johannes; Ursin, Rupert; Jennewein, Thomas; Brukner, Časlav; Zeilinger, Anton

    2012-06-01

    Motivated by the question of which kind of physical interactions and processes are needed for the production of quantum entanglement, Peres has put forward the radical idea of delayed-choice entanglement swapping. There, entanglement can be `produced a posteriori, after the entangled particles have been measured and may no longer exist'. Here, we report the realization of Peres's gedanken experiment. Using four photons, we can actively delay the choice of measurement--implemented through a high-speed tunable bipartite-state analyser and a quantum random-number generator--on two of the photons into the time-like future of the registration of the other two photons. This effectively projects the two already registered photons onto one of two mutually exclusive quantum states in which the photons are either entangled (quantum correlations) or separable (classical correlations). This can also be viewed as `quantum steering into the past'.

  15. Experimental delayed-choice entanglement swapping

    CERN Document Server

    Ma, Xiao-song; Kofler, Johannes; Ursin, Rupert; Jennewein, Thomas; Brukner, Časlav; Zeilinger, Anton

    2012-01-01

    Motivated by the question, which kind of physical interactions and processes are needed for the production of quantum entanglement, Peres has put forward the radical idea of delayed-choice entanglement swapping. There, entanglement can be "produced a posteriori, after the entangled particles have been measured and may no longer exist". In this work we report the first realization of Peres' gedanken experiment. Using four photons, we can actively delay the choice of measurement-implemented via a high-speed tunable bipartite state analyzer and a quantum random number generator-on two of the photons into the time-like future of the registration of the other two photons. This effectively projects the two already registered photons onto one definite of two mutually exclusive quantum states in which either the photons are entangled (quantum correlations) or separable (classical correlations). This can also be viewed as "quantum steering into the past".

  16. On fractional control method for four-wheel-steering vehicle

    Institute of Scientific and Technical Information of China (English)

    CHEN Ning; CHEN Nan; CHEN YanDong

    2009-01-01

    Four-wheel-steering (4WS) system can enhance vehicle cornering ability by steering the rear wheels in accordance with the front wheels steering and vehicle status. With such steering control system, it becomes possible to improve the lateral stability and handling performance, in this paper, a new control method for 4WS vehicle is proposed, its rear wheels steering angle is in accordance with the angle of front wheels steering and vehicle yaw rate, and the effects of front wheels steering angle velocity are considered by adopting the fractional derivative theory. Some design specifications for control law are also given. The effects of the control method are verified by a kind of numerical scheme presented in this paper. The dynamic characteristics such as the side-slip angle and the yaw angle velocity of the vehicle gravity center are compared among three kinds of vehicles with different control methods. And the kinematics characteristics such as turning radius between 4WS and 2WS are also discussed. Nu-merical simulation shows that the control method presented can improve the transient response and reduce the turning radius of 4WS vehicle.

  17. On fractional control method for four-wheel-steering vehicle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Four-wheel-steering (4WS) system can enhance vehicle cornering ability by steering the rear wheels in accordance with the front wheels steering and vehicle status. With such steering control system, it becomes possible to improve the lateral stability and handling performance. In this paper, a new control method for 4WS vehicle is proposed, its rear wheels steering angle is in accordance with the angle of front wheels steering and vehicle yaw rate, and the effects of front wheels steering angle velocity are considered by adopting the fractional derivative theory. Some design specifications for control law are also given. The effects of the control method are verified by a kind of numerical scheme presented in this paper. The dynamic characteristics such as the side-slip angle and the yaw angle velocity of the vehicle gravity center are compared among three kinds of vehicles with different control methods. And the kinematics characteristics such as turning radius between 4WS and 2WS are also discussed. Nu- merical simulation shows that the control method presented can improve the transient response and reduce the turning radius of 4WS vehicle.

  18. Quantum steering: a review with focus on semidefinite programming

    Science.gov (United States)

    Cavalcanti, D.; Skrzypczyk, P.

    2017-02-01

    Quantum steering refers to the non-classical correlations that can be observed between the outcomes of measurements applied on half of an entangled state and the resulting post-measured states that are left with the other party. From an operational point of view, a steering test can be seen as an entanglement test where one of the parties performs uncharacterised measurements. Thus, quantum steering is a form of quantum inseparability that lies in between the well-known notions of Bell nonlocality and entanglement. Moreover, quantum steering is also related to several asymmetric quantum information protocols where some of the parties are considered untrusted. Because of these facts, quantum steering has received a lot of attention both theoretically and experimentally. The main goal of this review is to give an overview of how to characterise quantum steering through semidefinite programming. This characterisation provides efficient numerical methods to address a number of problems, including steering detection, quantification, and applications. We also give a brief overview of some important results that are not directly related to semidefinite programming. Finally, we make available a collection of semidefinite programming codes that can be used to study the topics discussed in this article.

  19. Monkey steering responses reveal rapid visual-motor feedback.

    Directory of Open Access Journals (Sweden)

    Seth W Egger

    Full Text Available The neural mechanisms underlying primate locomotion are largely unknown. While behavioral and theoretical work has provided a number of ideas of how navigation is controlled, progress will require direct physiolgical tests of the underlying mechanisms. In turn, this will require development of appropriate animal models. We trained three monkeys to track a moving visual target in a simple virtual environment, using a joystick to control their direction. The monkeys learned to quickly and accurately turn to the target, and their steering behavior was quite stereotyped and reliable. Monkeys typically responded to abrupt steps of target direction with a biphasic steering movement, exhibiting modest but transient overshoot. Response latencies averaged approximately 300 ms, and monkeys were typically back on target after about 1 s. We also exploited the variability of responses about the mean to explore the time-course of correlation between target direction and steering response. This analysis revealed a broad peak of correlation spanning approximately 400 ms in the recent past, during which steering errors provoke a compensatory response. This suggests a continuous, visual-motor loop controls steering behavior, even during the epoch surrounding transient inputs. Many results from the human literature also suggest that steering is controlled by such a closed loop. The similarity of our results to those in humans suggests the monkey is a very good animal model for human visually guided steering.

  20. Generation of electron Airy beams.

    Science.gov (United States)

    Voloch-Bloch, Noa; Lereah, Yossi; Lilach, Yigal; Gover, Avraham; Arie, Ady

    2013-02-21

    Within the framework of quantum mechanics, a unique particle wave packet exists in the form of the Airy function. Its counterintuitive properties are revealed as it propagates in time or space: the quantum probability wave packet preserves its shape despite dispersion or diffraction and propagates along a parabolic caustic trajectory, even though no force is applied. This does not contradict Newton's laws of motion, because the wave packet centroid propagates along a straight line. Nearly 30 years later, this wave packet, known as an accelerating Airy beam, was realized in the optical domain; later it was generalized to an orthogonal and complete family of beams that propagate along parabolic trajectories, as well as to beams that propagate along arbitrary convex trajectories. Here we report the experimental generation and observation of the Airy beams of free electrons. These electron Airy beams were generated by diffraction of electrons through a nanoscale hologram, which imprinted on the electrons' wavefunction a cubic phase modulation in the transverse plane. The highest-intensity lobes of the generated beams indeed followed parabolic trajectories. We directly observed a non-spreading electron wavefunction that self-heals, restoring its original shape after passing an obstacle. This holographic generation of electron Airy beams opens up new avenues for steering electronic wave packets like their photonic counterparts, because the wave packets can be imprinted with arbitrary shapes or trajectories.

  1. Lean color characteristics of bullock and steer beef.

    Science.gov (United States)

    Shackelford, S D; Purser, D E; Smith, G C; Griffin, C L; Stiffler, D M; Savell, J W

    1992-02-01

    Twelve young bulls and 12 steers were slaughtered and the carcasses were fabricated at 48 h postmortem. Top rounds, bottom rounds, and rib eyes were vacuum-packaged and stored at 0 degrees C until 21 d postmortem. After subprimal storage, steaks were removed from each cut and displayed under simulated retail conditions for 3 d. Consumer panelists (n = 110) showed little difference in buying preference for top round, bottom round, and rib eye steaks from steers vs bullocks. Also, consumer panelists could not detect color differences between steaks from steers and bullocks. Experienced panelists (n = 6) detected brighter (P less than .05) muscle color for top round and rib eye steaks from steers but detected no difference in muscle color of bottom round steaks from bullocks and steers. Generally, overall desirability scores favored steaks from steer carcasses. This was particularly true of rib eye steaks. Sex-class of carcass did not affect aerobic plate counts of top round, bottom round, or rib eye steaks either before or after 3 d of retail display. Muscle pH was lower for top round and rib eye steaks from steer carcasses; however, the magnitude of this difference was not large enough to affect retail display stability. Muscle pH of bottom round steaks was not affected by sex-class. Although experienced panelists could detect differences in visual appearance of beef retail cuts from steers and bullocks, consumer panelists did not show a clear purchase preference for steer vs bullock beef. These data suggest that beef retail cuts from bullocks are acceptable in visual appearance.

  2. FLOW CHARACTERISTICS FORMATION OF POWER STEERING WITH ROTARY DISTRIBUTOR

    OpenAIRE

    Mikhailov, V; E. Strock

    2012-01-01

    In order to obtain an adequate mathematical model of vehicle hydro-mechanical steering which is  equipped with a steering mechanism combined with power steering and a rotary distributor  it is initially   necessary to get current consumption values in the units of hydraulic scheme which are determined by dynamic changes of flow passages of pressure and drain circuits according to turning angle of the distributor. Such characteristics are usually determined experimentally.The paper  proposes  ...

  3. Selection and Simulation of Electric Steering Gear Control System

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2013-06-01

    Full Text Available For the electric steering gear control systems, the principle of the system is introduced. Specific model and parameters are selected to deduce the optimal combination of control system and choices method of the steering system model is determined. The transfer function of motor according to the parameters is achieved and simulation results are gained based on MATLAB. Simulation results show that this method can meet the performance requirements of electric steering gear, the control method is simple and easy to work to achieve.

  4. Steering Control of Wheeled Armored Vehicle with Brushless DC Motor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Considering the steering characters of one type of wheeled armored vehicle, a brushless direct current (DC) motor is adapted as the actuator for steering control. After investigating the known algorithms, one kind of algorithm, which combines the fuzzy logic control with the self-adapting PID control and the startup and pre-brake control, is put forward. Then a test-bed is constructed, and an experiment is conducted. The result of experiment confirms the validity of this algorithm in steering control of wheeled armored vehicle with brushless DC motor.

  5. The beam delivery modeling and error sources analysis of beam stabilization system for lithography

    Science.gov (United States)

    Wang, Jun; Huang, Lihua; Hou, Liying; He, Guojun; Ren, Bingqiang; Zeng, Aijun; Huang, Huijie

    2013-12-01

    Beam stabilization system is one of the most important units for lithography, which can accomplish displacement and pointing detection and control and includes beam measurement unit(BMU) and beam steering unit(BSU). Our group has set up a beam stabilization system and verified preliminarily beam stabilization algorithm of precise control beam position and angle. In the article, we establish beam delivery mathematic model and analyze the system inherent error. This shows that the reason why image rotation effect arises at the output plane of beam stabilization is the fast steering mirror (FSM) rotation of BSU in the process of beam stabilization. Two FSMs rotation around 45o axis of FSM make the most contribution to image rotation which rotates 1.414 mrad as two FSMs rotation angle difference changes 1 mrad. It is found that error sources include three key points: FSM accuracy; measurement noise and beam translation by passing through of beam splitters changing as the ambient temperature changing. FSM accuracy leads to the maximum 13.2μm displacement error and 24.49μrad angle error. Measurement inaccuracy as a result of 5μm measurement noise results in the maximum 0.126mm displacement error and 57.2μrad angle error. Beam translation errors can be negligible if temperature is unchanged. We have achieved beam stability of about 15.5μrad for angle and 28μm for displacement (both 1σ) after correcting 2mm initial displacement deviation and 5mrad initial angle deviation with regard to the system rebuilt due to practical requirements.

  6. 46 CFR 58.25-10 - Main and auxiliary steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Main and auxiliary steering gear. 58.25-10 Section 58.25... AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-10 Main and auxiliary steering gear. (a) Power-operated main and auxiliary steering gear must be separate systems that are independent throughout...

  7. 46 CFR 196.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Instructions for changing steering gear. 196.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering engineroom, relating in order, the different steps to be taken in changing to the emergency steering...

  8. Impact of feedback torque level on perceived comfort and control in steer-by-wire systems

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.H.; Martens, J.B.

    2012-01-01

    Steer-by-Wire systems enable designers to offer completely personalized steering feel to drivers, unlike existing steering systems that offer limited or no personalization. In this paper we focus on feedback torque level, a significant factor for steering feel. Earlier studies indicate that the pref

  9. Dynamic characteristics of hydraulic power steering system with accumulator in load-haul-dump vehicle

    Institute of Scientific and Technical Information of China (English)

    杨忠炯; 何清华; 柳波

    2004-01-01

    Using hydraulic power steering system of model EIMCO 922 load-haul-dump vehicle as a simulation example, the dynamic characteristics of hydraulic power steering system in load-haul-dump vehicle were simulated and discussed with SIMULINK software and hydraulic control theory. The results show that the dynamic characteristics of hydraulic power steering system are improved obviously by using bladder accumulator, the hydraulic power steering system of model EIMCO 922 load-haul-dump vehicle generates vibration at the initial stage under the normal steering condition of pulse input, and its static response time is 0.25 s shorter than that without bladder accumulator. Under the normal steering working condition, the capacity of steering accumulator for absorbing pulse is directly proportional to the cross section area of connecting pipeline, and inversely proportional to the length of connecting pipeline. At the same time, the precharge pressure of nitrogen in steering accumulator should be 60%- 80% of the rated minimum working pressure of hydraulic power steering system. Under the abnormal steering working condition, the steering cylinder piston may obtain higher motion velocity, and the dynamic response velocity of hydraulic power steering system can be increased by reducing the pressure drop of hydraulic pipelines between the accumulator and steering cylinder and by increasing the rated pressure of hydraulic power steering system, but the dynamic characteristics of hydraulic power steering system in load-haul-dump vehicle have nothing to do with the precharge pressure of nitrogen in steering accumulator.

  10. FLEXIBLE 2-DOF STEERING MODEL OF MULTI-AXLE HEAVY-DUTY VEHICLE

    Institute of Scientific and Technical Information of China (English)

    Yang Bo; Wang Xuelin; Hu Yujin; Li Chenggang

    2004-01-01

    A flexible two degrees of freedom (2-DOF) steering model of multi-axle vehicle (MAV) is presented with considering the effect of frame flexibility based on the classic 2-DOF model. A method to calculate the frame flexibility is derived by using three moments equation. The steering stability of MAV is analyzed. The steering performance of MAV is also researched in frequency domain. Simulation results show that the dynamic effects of flexible model are more severe than rigid model and the flexible effect of frame will weaken the steering stability of MAV. Different disposals of steering axles lead to different steering characteristics of MAV. The in-phase steering mode improves the steering characteristics and stability at high speed. The anti-phase steering mode increases the steering mobility at low vehicle speed.

  11. Beam dynamics design studies of a superconducting radioactive ion beam postaccelerator

    CERN Document Server

    Fraser, M A; Jones, R M

    2011-01-01

    The HIE-ISOLDE project at CERN proposes a superconducting upgrade to increase the energy range and quality of the radioactive ion beams produced at ISOLDE, which are currently postaccelerated by the normal conducting radioactive ion beam experiment linac. The specification and design choices for the HIE-ISOLDE linac are outlined along with a comprehensive beam dynamics study undertaken to understand and mitigate the sources of beam emittance dilution. The dominant cause of transverse emittance growth was attributed to the coupling between the transverse and longitudinal motions through the phase dependence of the rf defocusing force in the accelerating cavities. A parametric resonance induced by the coupling was observed and its excitation surveyed as a function of transverse phase advance using numerical simulations and analytic models to understand and avoid the regions of transverse beam instability. Other sources of emittance growth were studied and where necessary ameliorated, including the beam steering...

  12. BEAM CONTAINMENT SYSTEM FOR NSLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, S.L.; Casey, W.; Job, P.K.

    2010-05-23

    The shielding design for the NSLS-II will provide adequate protection for the full injected beam loss in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of {le} 10% full beam. This will require a system to insure that beam losses don't exceed these levels for a period of time that could cause excessive radiation levels outside the shield walls. This beam containment system will measure, provide a level of control and alarm indication of the beam power losses along the beam path from the source (e-gun, linac) thru the injection system and the storage ring. This system will consist of collimators that will provide limits to (and potentially to measure) the beam miss-steering and control the loss points of the charge and monitors that will measure the average beam current losses along the beam path and alarm when this beam power loss exceeds the level set by the shielding specifications. This will require some new ideas in beam loss detection capability and collimation. The initial planning and R&D program will be presented.

  13. How Insect Flight Steering Muscles Work: e1001822

    National Research Council Canada - National Science Library

    Hedenstrom, Anders

    2014-01-01

    .... The hinge consists of several hardened and articulated cuticle elements called sclerites. This articulation is controlled by a great number of small steering muscles, whose function has been studied by means of kinematics and muscle activity...

  14. FLOW CHARACTERISTICS FORMATION OF POWER STEERING WITH ROTARY DISTRIBUTOR

    Directory of Open Access Journals (Sweden)

    V. Mikhailov

    2012-01-01

    Full Text Available In order to obtain an adequate mathematical model of vehicle hydro-mechanical steering which is  equipped with a steering mechanism combined with power steering and a rotary distributor  it is initially   necessary to get current consumption values in the units of hydraulic scheme which are determined by dynamic changes of flow passages of pressure and drain circuits according to turning angle of the distributor. Such characteristics are usually determined experimentally.The paper  proposes  a sequence which is recommended for determination of consumption characteristics which is formed with due account of multi-directional kinematic perturbations, mechanical clearance, possible emergence of hydraulic backlash and desired throttling law. The factors account makes it possible to obtain an acceptable mathematical analogue of a hydro-mechanical steering for execution of robust investigations. 

  15. CCCT - NCTN Steering Committees - Pediatric and Adolescent Tumor

    Science.gov (United States)

    The Pediatric and Adolescent Solid Tumor Steering Committee addresses the design, prioritization and evaluation of concepts for large phase 2 and phase 3 clinical trials in extracranial solid tumors of children and youth.

  16. Current focusing and steering: modeling, physiology, and psychophysics.

    Science.gov (United States)

    Bonham, Ben H; Litvak, Leonid M

    2008-08-01

    Current steering and current focusing are stimulation techniques designed to increase the number of distinct perceptual channels available to cochlear implant (CI) users by adjusting currents applied simultaneously to multiple CI electrodes. Previous studies exploring current steering and current focusing stimulation strategies are reviewed, including results of research using computational models, animal neurophysiology, and human psychophysics. Preliminary results of additional neurophysiological and human psychophysical studies are presented that demonstrate the success of current steering strategies in stimulating auditory nerve regions lying between physical CI electrodes, as well as current focusing strategies that excite regions narrower than those stimulated using monopolar configurations. These results are interpreted in the context of perception and speech reception by CI users. Disparities between results of physiological and psychophysical studies are discussed. The differences in stimulation used for physiological and psychophysical studies are hypothesized to contribute to these disparities. Finally, application of current steering and focusing strategies to other types of auditory prostheses is also discussed.

  17. A control theoretic model of driver steering behavior

    Science.gov (United States)

    Donges, E.

    1977-01-01

    A quantitative description of driver steering behavior such as a mathematical model is presented. The steering task is divided into two levels: (1) the guidance level involving the perception of the instantaneous and future course of the forcing function provided by the forward view of the road, and the response to it in an anticipatory open-loop control mode; (2) the stabilization level whereby any occuring deviations from the forcing function are compensated for in a closed-loop control mode. This concept of the duality of the driver's steering activity led to a newly developed two-level model of driver steering behavior. Its parameters are identified on the basis of data measured in driving simulator experiments. The parameter estimates of both levels of the model show significant dependence on the experimental situation which can be characterized by variables such as vehicle speed and desired path curvature.

  18. Steering of Solar Sails Using Optical Lift Force Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This study seeks to look beyond the use of radiation pressure for thrust, and to explore a means of solar navigation whereby a solar craft would be steered by use...

  19. An improved constrained steering law for SGCMGs with DPC

    Institute of Scientific and Technical Information of China (English)

    Lei Jin; Shijie Xu

    2009-01-01

    An improved constrained (IC) steering law for single girnbal control moment gyros (SGCMGs) with deformed pyramid configuration (DPC) is proposed. First of all, the original system with five pyramid configuration (FPC) whose two adjacent gyros are in failure state is reconfigured as a degraded system with DPC. Then, the singular angular momentum hypersurfaces of the original and the degraded systems are plotted via the singular angular momentum equation of SGCMGs. Based on singular surfaces, the differences between FPC and DPC in singularity and momentum envelope are obtained directly, which provide an important reference for steering law design of DPC. Finally, an IC steering law is designed and applied to DPC. The simulation results demonstrate that the IC steering law has advantages in simplicity of calculation, avoidance of singularity and exactness of output torque, which endow the degraded system with fine controllability in a restricted workspace.

  20. Electrical power assisted steering for EVs and HEVs

    Institute of Scientific and Technical Information of China (English)

    Ma Haibo; Yang Ying

    2011-01-01

    Electrical power assisted steering (EPAS) is one of the key components, especially for electrical vehicle. It has attracted much attention for their advantages with respect to improved fuel economy and has been widely adopted as automotive power-steering equipment in recent years. EPS (electrical power steering) controllers contain MCU (microprocessor control unit) to implement the complex control algorithms. EPS control strategy development is the core technology of the whole system. To achieve the better performance of driving, both mechanical structures and electrical structures are totally designed as a whole. Model-based development is recommended to software design. There are several trends about EPS' future, such as high power EPS development, high voltage EPS development and steering-bywire technology.

  1. 46 CFR 58.25-70 - Steering-gear control systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering-gear control systems. 58.25-70 Section 58.25-70... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-70 Steering-gear control systems. (a) Each power-driven steering-gear system must be provided with at least one steering-gear control system. (b) The main...

  2. Optimization Under Uncertainty for Wake Steering Strategies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Annoni, Jennifer [National Renewable Energy Laboratory (NREL), Golden, CO (United States); King, Ryan N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fleming, Paul A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ning, Andrew [Brigham Young University

    2017-05-01

    Wind turbines in a wind power plant experience significant power losses because of aerodynamic interactions between turbines. One control strategy to reduce these losses is known as 'wake steering,' in which upstream turbines are yawed to direct wakes away from downstream turbines. Previous wake steering research has assumed perfect information, however, there can be significant uncertainty in many aspects of the problem, including wind inflow and various turbine measurements. Uncertainty has significant implications for performance of wake steering strategies. Consequently, the authors formulate and solve an optimization under uncertainty (OUU) problem for finding optimal wake steering strategies in the presence of yaw angle uncertainty. The OUU wake steering strategy is demonstrated on a two-turbine test case and on the utility-scale, offshore Princess Amalia Wind Farm. When we accounted for yaw angle uncertainty in the Princess Amalia Wind Farm case, inflow-direction-specific OUU solutions produced between 0% and 1.4% more power than the deterministically optimized steering strategies, resulting in an overall annual average improvement of 0.2%. More importantly, the deterministic optimization is expected to perform worse and with more downside risk than the OUU result when realistic uncertainty is taken into account. Additionally, the OUU solution produces fewer extreme yaw situations than the deterministic solution.

  3. Delayed childbearing.

    Science.gov (United States)

    Francis, H H

    1985-06-01

    In many Western nations, including England and Wales, Sweden, and the US, there is a current trend towards delayed childbearing because of women's pursuit of a career, later marriage, a longer interval between marriage and the 1st birth, and the increasing number of divorcees having children in a 2nd marriage. Wives of men in social classes I and II in England and Wales are, on average, having their 1st child at 27.9 years, 1.6 years later than in 1973, and in social classes IV and V, 1.0 years later than in 1973, at a mean age of 23.7 years. Consequently, the total period fertility rate for British women aged 30-34 years, 35-39 years, and 40 and over increased by 4%, 2%, and 4%, respectively, between 1982-83, in contrast to reductions of 2% and 3%, respectively, in the 15-19 year and 20-24 year age groups, with the 25-29-year-olds remaining static. The average maternal mortality for all parties in England and Wales during 1976-78 was 106/million for adolescents, 70.4/million for 20-24 year-olds, and 1162/million for those aged 40 years and older. The specific obstetric and allied conditions which increase with age are the hypertensive diseases of pregnancy, hemorrhage, pulmonary embolism, abortion, cardiac disease, caesarean section, ruptured uterus, and amniotic fluid embolism. The Swedish Medical Birth Registry of all live births and perinatal deaths since 1973 has shown that the risk of late fetal death is significantly greater in women aged 30-39 years than in those of the same parity and gravidity aged 20-24 years. The risk of giving birth to low birth weight babies preterm and at term and of premature labor are similarly increased. The early neonatal death rate also was increased for primigravidas and nulliparas in the 30-39 year age group but not in parous women. This is, in part, due to the rise in incidence of fetal abnormalities with advancing maternal age because of chromosomal and nonchromosomal anomalies. These also appear to be the cause of the

  4. High-Directivity Emissions with Flexible Beam Numbers and Beam Directions Using Gradient-Refractive-Index Fractal Metamaterial

    OpenAIRE

    2014-01-01

    A three-dimensional (3D) highly-directive emission system is proposed to enable beam shaping and beam steering capabilities in wideband frequencies. It is composed of an omnidirectional source antenna and several 3D gradient-refractive-index (GRIN) lenses. To engineer a broadband impedance match, the design method for these 3D lenses is established under the scenario of free-space excitation by using a planar printed monopole. For realizations and demonstrations, a kind of GRIN metamaterial i...

  5. The ATLAS High Level Trigger Steering

    CERN Document Server

    Berger, N; Eifert, T; Fischer, G; George, S; Haller, J; Höcker, A; Masik, J; Zur Nedden, M; Pérez-Réale, V; Risler, C; Schiavi, C; Stelzer, J; Wu, X; International Conference on Computing in High Energy and Nuclear Physics

    2008-01-01

    The High Level Trigger (HLT) of the ATLAS experiment at the Large Hadron Collider receives events which pass the LVL1 trigger at ~75 kHz and has to reduce the rate to ~200 Hz while retaining the most interesting physics. It is a software trigger and performs the reduction in two stages: the LVL2 trigger and the Event Filter (EF). At the heart of the HLT is the Steering software. To minimise processing time and data transfers it implements the novel event selection strategies of seeded, step-wise reconstruction and early rejection. The HLT is seeded by regions of interest identified at LVL1. These and the static configuration determine which algorithms are run to reconstruct event data and test the validity of trigger signatures. The decision to reject the event or continue is based on the valid signatures, taking into account pre-scale and pass-through. After the EF, event classification tags are assigned for streaming purposes. Several powerful new features for commissioning and operation have been added: co...

  6. Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems.

    Science.gov (United States)

    Tian, Jing; Yang, Wenshu; Peng, Zhenming; Tang, Tao; Li, Zhijun

    2016-03-25

    In a charge-coupled device (CCD)-based fast steering mirror (FSM) tracking control system, high control bandwidth is the most effective way to enhance the closed-loop performance. However, the control system usually suffers a great deal from mechanical resonances and time delays induced by the low sampling rate of CCDs. To meet the requirements of high precision and load restriction, fiber-optic gyroscopes (FOGs) are usually used in traditional FSM tracking control systems. In recent years, the MEMS accelerometer and gyroscope are becoming smaller and lighter and their performance have improved gradually, so that they can be used in a fast steering mirror (FSM) to realize the stabilization of the line-of-sight (LOS) of the control system. Therefore, a tentative approach to implement a CCD-based FSM tracking control system, which uses MEMS accelerometers and gyroscopes as feedback components and contains an acceleration loop, a velocity loop and a position loop, is proposed. The disturbance suppression of the proposed method is the product of the error attenuation of the acceleration loop, the velocity loop and the position loop. Extensive experimental results show that the MEMS accelerometers and gyroscopes can act the similar role as the FOG with lower cost for stabilizing the LOS of the FSM tracking control system.

  7. Dual polarized receiving steering antenna array for measurement of ultrawideband pulse polarization structure

    Science.gov (United States)

    Balzovsky, E. V.; Buyanov, Yu. I.; Koshelev, V. I.; Nekrasov, E. S.

    2016-03-01

    To measure simultaneously two orthogonal components of the electromagnetic field of nano- and subnano-second duration, an antenna array has been developed. The antenna elements of the array are the crossed dipoles of dimension 5 × 5 cm. The arms of the dipoles are connected to the active four-pole devices to compensate the frequency response variations of a short dipole in the frequency band ranging from 0.4 to 4 GHz. The dipoles have superimposed phase centers allowing measuring the polarization structure of the field in different directions. The developed antenna array is the linear one containing four elements. The pattern maximum position is controlled by means of the switched ultrawideband true time delay lines. Discrete steering in seven directions in the range from -40° to +40° has been realized. The error at setting the pattern maximum position is less than 4°. The isolation of the polarization exceeds 29 dB in the direction orthogonal to the array axis and in the whole steering range it exceeds 23 dB. Measurement results of the polarization structure of radiated and scattered pulses with different polarization are presented as well.

  8. Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems

    Directory of Open Access Journals (Sweden)

    Jing Tian

    2016-03-01

    Full Text Available In a charge-coupled device (CCD-based fast steering mirror (FSM tracking control system, high control bandwidth is the most effective way to enhance the closed-loop performance. However, the control system usually suffers a great deal from mechanical resonances and time delays induced by the low sampling rate of CCDs. To meet the requirements of high precision and load restriction, fiber-optic gyroscopes (FOGs are usually used in traditional FSM tracking control systems. In recent years, the MEMS accelerometer and gyroscope are becoming smaller and lighter and their performance have improved gradually, so that they can be used in a fast steering mirror (FSM to realize the stabilization of the line-of-sight (LOS of the control system. Therefore, a tentative approach to implement a CCD-based FSM tracking control system, which uses MEMS accelerometers and gyroscopes as feedback components and contains an acceleration loop, a velocity loop and a position loop, is proposed. The disturbance suppression of the proposed method is the product of the error attenuation of the acceleration loop, the velocity loop and the position loop. Extensive experimental results show that the MEMS accelerometers and gyroscopes can act the similar role as the FOG with lower cost for stabilizing the LOS of the FSM tracking control system.

  9. Dual polarized receiving steering antenna array for measurement of ultrawideband pulse polarization structure

    Energy Technology Data Exchange (ETDEWEB)

    Balzovsky, E. V.; Buyanov, Yu. I.; Koshelev, V. I., E-mail: koshelev@lhfe.hcei.tsc.ru; Nekrasov, E. S. [Institute of High Current Electronics SB RAS, IHCE SB RAS, Tomsk 634055 (Russian Federation)

    2016-03-15

    To measure simultaneously two orthogonal components of the electromagnetic field of nano- and subnano-second duration, an antenna array has been developed. The antenna elements of the array are the crossed dipoles of dimension 5 × 5 cm. The arms of the dipoles are connected to the active four-pole devices to compensate the frequency response variations of a short dipole in the frequency band ranging from 0.4 to 4 GHz. The dipoles have superimposed phase centers allowing measuring the polarization structure of the field in different directions. The developed antenna array is the linear one containing four elements. The pattern maximum position is controlled by means of the switched ultrawideband true time delay lines. Discrete steering in seven directions in the range from −40° to +40° has been realized. The error at setting the pattern maximum position is less than 4°. The isolation of the polarization exceeds 29 dB in the direction orthogonal to the array axis and in the whole steering range it exceeds 23 dB. Measurement results of the polarization structure of radiated and scattered pulses with different polarization are presented as well.

  10. Design of patient-specific focused ultrasound arrays for non-invasive brain therapy with increased trans-skull transmission and steering range

    Science.gov (United States)

    Hughes, Alec; Hynynen, Kullervo

    2017-09-01

    The use of a phased array of ultrasound transducer elements to sonicate through the skull has opened the way for new treatments and the delivery of therapeutics beyond the blood-brain barrier. The limited steering range of current clinical devices, particularly at higher frequencies, limits the regions of the brain that are considered treatable by ultrasound. A new array design is introduced that allows for high levels of beam steering and increased transmission throughout the brain. These improvements are achieved using concave transducers normal to the outer-skull surface in a patient-specific configuration to target within the skull, so that the far-field of each beam is within the brain. It is shown that by using pulsed ultrasound waves timed to arrive in-phase at the desired target, sufficient levels of acoustic energy are delivered for blood-brain barrier opening throughout the brain.

  11. Nonlocality of a single photon: paths to an EPR-steering experiment

    CERN Document Server

    Jones, S J

    2011-01-01

    A single photon incident on a beam splitter produces an entangled field state, and in principle could be used to violate a Bell-inequality, but such an experiment (without post-selection) is beyond the reach of current experiments. Here we consider the somewhat simpler task of demonstrating EPR-steering with a single photon (also without post-selection). That is, of demonstrating that Alice's choice of measurement on her "half" of a single photon can affect the other "half" of the photon in Bob's lab, in a sense rigorously defined by us and Doherty [Phys. Rev. Lett. 98, 140402 (2007)]. Previous work by Lvovsky and co-workers [Phys. Rev. Lett. 92, 047903 (2004)] has addressed this phenomenon (which they called "remote preparation") experimentally using homodyne measurements on a single photon. Here we show that, unfortunately, their experimental parameters do not meet the bounds necessary for a rigorous demonstration of EPR-steering with a single photon. However, we also show that modest improvements in the ex...

  12. BEAMLINE-CONTROLLED STEERING OF SOURCE-POINT ANGLE AT THE ADVANCED PHOTON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Emery, L.; Fystro, G.; Shang, H.; Smith, M.

    2017-06-25

    An EPICS-based steering software system has been implemented for beamline personnel to directly steer the angle of the synchrotron radiation sources at the Advanced Photon Source. A script running on a workstation monitors "start steering" beamline EPICS records, and effects a steering given by the value of the "angle request" EPICS record. The new system makes the steering process much faster than before, although the older steering protocols can still be used. The robustness features of the original steering remain. Feedback messages are provided to the beamlines and the accelerator operators. Underpinning this new steering protocol is the recent refinement of the global orbit feedback process whereby feedforward of dipole corrector set points and orbit set points are used to create a local steering bump in a rapid and seamless way.

  13. Effects of automobile steering characteristics on driver vehicle system dynamics in regulation tasks

    Science.gov (United States)

    Mcruer, D. T.; Klein, R.

    1975-01-01

    A regulation task which subjected the automobile to a random gust disturbance which is countered by driver control action is used to study the effects of various automobile steering characteristics on the driver/vehicle system. The experiments used a variable stability automobile specially configured to permit insertion of the simulated gust disturbance and the measurement of the driver/vehicle system characteristics. Driver/vehicle system dynamics were measured and interpreted as an effective open loop system describing function. Objective measures of system bandwidth, stability, and time delays were deduced and compared. These objective measures were supplemented by driver ratings. A tentative optimum range of vehicle dynamics for the directional regulation task was established.

  14. Backwards planning approach for rapid attitude maneuvers steering

    Science.gov (United States)

    Verbin, D.

    Remote sensing satellites are often built with payloads that do not include line of sight steering mechanisms. In cases, when frequent line of sight retargeting is required, there is a need for efficient actuators and control schemes that would support rapid attitude manoeuvring together with adequate pointing accuracy and stability between the manoeuvres. Within this frame, this research develops the Backwards Planning approach as one of the possible control methods for rapid manoeuvring. The method is based on state feedback and combines time efficient together with straight forward computation flow. Novel efficient methods to execute the Backwards Planning Control in the 3D attitude space are proposed here. The methods refer both for the first saturated control phase of the manoeuvre and for the last braking phase. The actuators used for the spacecraft control in this research are either Reaction Wheels (RWs) or Single Gimbal Control Moments Gyros (SGCMGs) or both of them together. The advantage of the SGCMG is in rapid rotational manoeuvring, but their application for high quality pointing requires very accurate gimbal mechanisms. On the other hand, RWs are usually more suitable for accurate pointing, but their torque to power performance is inferior in manoeuvring. It is shown that the coordination of SGCMGs and RWs together enables to draw more performance from the SGCMGs in terms of agility and meet the pointing requirements between manoeuvres where only the RWs are used. Novel SGCMG steering laws are suggested as well. While the steering laws determine the required angular rate for each gimbal, most steering laws are defined in the angular momentum domain and output the gimbals angular rates to produce a given required torque or angular momentum increment. This research however, practices a novel steering law in the gimbal angles domain. While both steering laws turn to be dynamically equivalent for small control signals, as in the steady state, it is shown

  15. Beam Dynamics Design Studies of a Superconducting Radioactive Ion Beam Post-accelerator

    CERN Document Server

    Fraser, MA; Pasini, M

    2011-01-01

    The HIE-ISOLDE project at CERN proposes a superconducting upgrade to increase the energy range and quality of the radioactive ion beams produced at ISOLDE, which are currently post- accelerated by the normal conducting REX linac. The specification and design choices for the HIE-ISOLDE linac are outlined along with a comprehensive beam dynamics study undertaken to understand and mitigate the sources of beam emittance dilution. The dominant cause of transverse emittance growth was attributed to the coupling between the transverse and longitudinal motions through the phase dependence of the rf defocusing force in the accelerating cavities. A parametric resonance induced by the coupling was observed and its excitation surveyed as a function of trans- verse phase advance using numerical simulations and analytic models to understand and avoid the regions of transverse beam instability. Other sources of emittance growth were studied and where necessary ameliorated, including the beam steering force in the quarter-wa...

  16. A HIGH RESOLUTION WIDE SWATH SAR METHOD BASED ON INTRA-PULSE NULL STEERING AND MIMO

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    High Resolution Wide Swath(HRWS)Synthetic Aperture Radar(SAR)often Sufiers from low Signal-to-Noise Ratio(SNR)due to small transmitting antenna,especially in phased array antenna systems.Digital Beam Forming(DBF)based on Single Input and Multiple Output(SIMO)achieves receiving array gain at the cost of increasing data rate.This letter proposes a new HRWS SAR method, which employs intra-pulse null steering to get receiving gain in elevation and decrease the data rate,and Multiple Input and Multiple Output(MIMO)using Space-Time Block Coding(STBC)in azimuth to get transmitting gain and receiving array gain simultaneously.The feasibility is verified by deduction and simulations.

  17. Beam Profiling through Wire Chambing Tracking

    CERN Document Server

    Nash, W

    2013-01-01

    This note describes the calibration of the Delay Wire Chambers (DWCs) used during test runs of CALICE’s Tungsten Digital Hadron Calorimeter (W-DHCAL) prototype in CERN’s SPS beam line (10 – 300 GeV).

  18. Wideband RF beamforming: architectures, time-delays and CMOS implementations

    NARCIS (Netherlands)

    Garakoui, Seyed Kasra

    2015-01-01

    A phased array antenna is a kind of antenna which is electronically reconfigurable to realize different antenna beam patterns. Delay blocks are an essential part of phased array antenna systems. Their delay-range, noise, nonlinearity, bandwidth, size, cost and power consumption have a dominant effec

  19. Field Test of Wake Steering at an Offshore Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Paul; Annoni, Jennifer; Shah, Jigar J.; Wang, Linpeng; Ananthan, Shreyas; Zhang, Zhijun; Hutchings, Kyle; Wang, Peng; Chen, Weiguo; Chen, Lin

    2017-02-06

    In this paper, a field test of wake steering control is presented. The field test is the result of a collaboration between the National Renewable Energy Laboratory (NREL) and Envision Energy, a smart energy management company and turbine manufacturer. In the campaign, an array of turbines within an operating commercial offshore wind farm in China have the normal yaw controller modified to implement wake steering according to a yaw control strategy. The strategy was designed using NREL wind farm models, including a computational fluid dynamics model, SOWFA, for understanding wake dynamics and an engineering model, FLORIS, for yaw control optimization. Results indicate that, within the certainty afforded by the data, the wake-steering controller was successful in increasing power capture, by amounts similar to those predicted from the models.

  20. Application of H infinite control to ship steering system

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Because the general object of ship steering control system is singular, the state of rudder force and the state of disturbance are separated, and the generalized yaw output disturbance is obtained. Furthermore, singular system control problem of ship yaw and sway coupled system is transferred into nonsingular standard control problem. Then according to the linear fractional denoting algorithm of the rational function parameter perturbation system, the Linear Fractional Transform (LFT) model of yaw and sway coupled motion is solved, which is used to design the ship steering robust control system. For the ship steering system with the uncertain parameters, the robust control law is designed based on H∞μ-synthesis. And the robust performance of the system is analyzed and the simulation validation is made. Simulation results show that the designed control system has excellent control effect and robustness.

  1. A Parallel and Distributed Surrogate Model Implementation for Computational Steering

    KAUST Repository

    Butnaru, Daniel

    2012-06-01

    Understanding the influence of multiple parameters in a complex simulation setting is a difficult task. In the ideal case, the scientist can freely steer such a simulation and is immediately presented with the results for a certain configuration of the input parameters. Such an exploration process is however not possible if the simulation is computationally too expensive. For these cases we present in this paper a scalable computational steering approach utilizing a fast surrogate model as substitute for the time-consuming simulation. The surrogate model we propose is based on the sparse grid technique, and we identify the main computational tasks associated with its evaluation and its extension. We further show how distributed data management combined with the specific use of accelerators allows us to approximate and deliver simulation results to a high-resolution visualization system in real-time. This significantly enhances the steering workflow and facilitates the interactive exploration of large datasets. © 2012 IEEE.

  2. Signal Processing Strategies for Cochlear Implants Using Current Steering

    Directory of Open Access Journals (Sweden)

    Waldo Nogueira

    2009-01-01

    Full Text Available In contemporary cochlear implant systems, the audio signal is decomposed into different frequency bands, each assigned to one electrode. Thus, pitch perception is limited by the number of physical electrodes implanted into the cochlea and by the wide bandwidth assigned to each electrode. The Harmony HiResolution bionic ear (Advanced Bionics LLC, Valencia, CA, USA has the capability of creating virtual spectral channels through simultaneous delivery of current to pairs of adjacent electrodes. By steering the locus of stimulation to sites between the electrodes, additional pitch percepts can be generated. Two new sound processing strategies based on current steering have been designed, SpecRes and SineEx. In a chronic trial, speech intelligibility, pitch perception, and subjective appreciation of sound were compared between the two current steering strategies and standard HiRes strategy in 9 adult Harmony users. There was considerable variability in benefit, and the mean results show similar performance with all three strategies.

  3. Theory of using magnetic deflections to combine charged particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Steckbeck, Mackenzie K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Doyle, Barney Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Several radiation effects projects in the Ion Beam Lab (IBL) have recently required two disparate charged particle beams to simultaneously strike a single sample through a single port of the target chamber. Because these beams have vastly different mass–energy products (MEP), the low-MEP beam requires a large angle of deflection toward the sample by a bending electromagnet. A second electromagnet located further upstream provides a means to compensate for the small angle deflection experienced by the high-MEP beam during its path through the bending magnet. This paper derives the equations used to select the magnetic fields required by these two magnets to achieve uniting both beams at the target sample. A simple result was obtained when the separation of the two magnets was equivalent to the distance from the bending magnet to the sample, and the equation is given by: Bs= 1/2(rc/rs) Bc, where Bs and Bc are the magnetic fields in the steering and bending magnet and rc/rs is the ratio of the radii of the bending magnet to that of the steering magnet. This result is not dependent upon the parameters of the high MEP beam, i.e. energy, mass, charge state. Therefore, once the field of the bending magnet is set for the low-MEP beam, and the field in the steering magnet is set as indicted in the equation, the trajectory path of any high-MEP beam will be directed into the sample.

  4. Improved LTVMPC design for steering control of autonomous vehicle

    Science.gov (United States)

    Velhal, Shridhar; Thomas, Susy

    2017-01-01

    An improved linear time varying model predictive control for steering control of autonomous vehicle running on slippery road is presented. Control strategy is designed such that the vehicle will follow the predefined trajectory with highest possible entry speed. In linear time varying model predictive control, nonlinear vehicle model is successively linearized at each sampling instant. This linear time varying model is used to design MPC which will predict the future horizon. By incorporating predicted input horizon in each successive linearization the effectiveness of controller has been improved. The tracking performance using steering with front wheel and braking at four wheels are presented to illustrate the effectiveness of the proposed method.

  5. Study on Characteristic of Electric Power Assist Steering System

    Institute of Scientific and Technical Information of China (English)

    许镇琳; 王豪; 尚喆; 张海华; 王家军

    2003-01-01

    A pinion-type electric power steering (EPS) equipped on a sedan is reached in this paper. A three-freedom dynamic model of this system is created. The variables affecting assist character is analyzed. The formulas of simpled steering resistance force and the relationship between assist gain and vehicle speed are presented for the first time. Assist character is found based on the parameters of a sedan at last. This assist character is fit for the control rule of the EPS system through analyzing this character. The assist character figure offers reference for system design and control. Furthermore, this research method has generality for assist character of different kinds of vehicles.

  6. Detailed field test of yaw-based wake steering

    DEFF Research Database (Denmark)

    Fleming, P.; Churchfield, M.; Scholbrock, A.

    2016-01-01

    This paper describes a detailed field-test campaign to investigate yaw-based wake steering. In yaw-based wake steering, an upstream turbine intentionally misaligns its yaw with respect to the inflow to deflect its wake away from a downstream turbine, with the goal of increasing total power...... production. In the first phase, a nacelle-mounted scanning lidar was used to verify wake deflection of a misaligned turbine and calibrate wake deflection models. In the second phase, these models were used within a yaw controller to achieve a desired wake deflection. This paper details the experimental...

  7. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    2015-01-01

    by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME......This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...

  8. Opto-VLSI-based photonic true-time delay architecture for broadband adaptive nulling in phased array antennas.

    Science.gov (United States)

    Juswardy, Budi; Xiao, Feng; Alameh, Kamal

    2009-03-16

    This paper proposes a novel Opto-VLSI-based tunable true-time delay generation unit for adaptively steering the nulls of microwave phased array antennas. Arbitrary single or multiple true-time delays can simultaneously be synthesized for each antenna element by slicing an RF-modulated broadband optical source and routing specific sliced wavebands through an Opto-VLSI processor to a high-dispersion fiber. Experimental results are presented, which demonstrate the principle of the true-time delay unit through the generation of 5 arbitrary true-time delays of up to 2.5 ns each.

  9. 76 FR 69769 - Annual Public Meeting of the Interagency Steering Committee on Multimedia Environmental Modeling

    Science.gov (United States)

    2011-11-09

    ... indication of citizenship and affiliation) may be faxed or emailed to: Mark Fuhrmann, Environmental Transport... COMMISSION Annual Public Meeting of the Interagency Steering Committee on Multimedia Environmental Modeling... the Federal Interagency Steering Committee on Multimedia Environmental Modeling (ISCMEM) will...

  10. Effects of slow-release urea on ruminal digesta characteristics and growth performance in beef steers

    DEFF Research Database (Denmark)

    Taylor-Edwards, C C; Hibbard, G; Kitts, S E

    2009-01-01

    Two experiments were conducted to evaluate the effects of slow urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers.......Two experiments were conducted to evaluate the effects of slow urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers....

  11. Steering laws analysis of SGCMGs based on singular value decomposition theory

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-rui

    2008-01-01

    The steering laws of single gimbal control moment gyros (SGCMGs) are analyzed and compared in this paper for a spacecraft attitude control system based on singular value decomposition (SVD) theory. The mechanism of steering laws escaping singularity, especially how the steering laws affect singularity of gimbal configuration and the output torque error, is studied using SVD theory. Performance of various steering laws are analyzed and compared quantitatively by simulation. The obtained results can be used as a reference for designers.

  12. The Beam Profile Monitoring System for the CERN IRRAD Proton Facility

    CERN Document Server

    Ravotti, F; Glaser, M; Matli, E; Pezzullo, G; Gan, K K; Kagan, H; Smith, S; Warner, J D

    2016-01-01

    To perform proton irradiation experiments, CERN built during LS1 a new irradiation facility in the East Area at the Proton Synchrotron accelerator. At this facility, named IR-RAD, a high-intensity 24 GeV/c proton beam is used. During beam steering and irradiation, the intensity and the transverse profile of the proton beam are monitored online with custom-made Beam Profile Monitor (BPM) devices. In this work, we present the design and the architecture of the IRRAD BPM system, some results on its performance with the proton beam, as well as its planned grades.

  13. Potential for Fabric Damage by Welding Electron Beam

    Science.gov (United States)

    Fragomeni, James M.; Nunes, Arthur C., Jr.

    1998-01-01

    Welding electron beam effects on Nextel AF-62 ceramic fabric enable a preliminary, tentative interpretation of electron beam fabric damage. Static surface charging does not protect fabric from beam penetration, but penetration occurs only after a delay time. The delay time is thought to be that required for the buildup of outgassing products at the fabric surface to a point where arcing occurs. Extra long delays are noted when the gun is close enough to the surface to be shut off by outgassing emissions. Penetration at long distances is limited by beam attenuation from electronic collisions with the chamber atmosphere.

  14. 46 CFR 78.47-55 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Instructions for changing steering gear. 78.47-55... OPERATIONS Markings for Fire and Emergency Equipment, Etc. § 78.47-55 Instructions for changing steering gear..., relating in order, the different steps to be taken in changing to the emergency steering gear. Each...

  15. 46 CFR 97.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 97.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering... gear. Each clutch, gear, wheel, lever, valve, or switch which is used during the changeover shall...

  16. 46 CFR 130.140 - Steering on OSVs of 100 or more gross tons.

    Science.gov (United States)

    2010-10-01

    ... hydraulic-helm steering-system in paragraph (b) of this section. (b) Each hydraulic-helm steering-system... the vessel at every service speed without being damaged at maximum astern speed. (2) A hydraulic... stops. (6) Either— (i) Two steering pumps in accordance with § 130.130(c)(3) of this part; or (ii)...

  17. 7 CFR 59.103 - Mandatory weekly reporting for steers and heifers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Mandatory weekly reporting for steers and heifers. 59... (CONTINUED) LIVESTOCK MANDATORY REPORTING Cattle Reporting § 59.103 Mandatory weekly reporting for steers and heifers. (a) In general. The corporate officers or officially designated representatives of each steer...

  18. The Impact of Analog and Bang-Bang Steering Gear Control on Ship's Fuel Economy

    DEFF Research Database (Denmark)

    Nørtoft Thomsen, J. C.; Blanke, Mogens; Reid, R. E.

    1982-01-01

    it is found to be at least equally important regarding steering performance and fuel economy. The paper presents a comprehensive survey of steering gear principles commonly used, including relevant details of three analog steering gear servo principles, which have outperformed conventional designs. Control...

  19. LHC One-turn Delay Feedback Commissioning

    CERN Document Server

    Mastoridis, T; Molendijk, J

    2012-01-01

    The LHC One-Turn delay FeedBack (OTFB) is an FPGA based feedback system part of the LHC cavity controller, which produces gain only around the revolution frequency (frev = 11.245 kHz) harmonics. As such, it helps reduce the transient beam loading and effective cavity impedance. Consequently, it increases the stability margin for Longitudinal Coupled Bunch Instabilities driven by the cavity impedance at the fundamental and allows reliable operation at higher beam currents. The OTFB was commissioned on all sixteen cavities in mid-October 2011 and has been used in operation since. The commissioning procedure and algorithms for setting-up are presented. The resulting improvements in transient beam loading, beam stability, and required klystron power are analyzed. The commissioning of the OTFB reduced the cavity voltage phase modulation from approximately six degrees peak-to-peak to below one degree at 400 MHz with nominal bunch intensity of 1.1e11 protons.

  20. Single-laser, one beam, tetrahedral magneto-optical trap.

    Science.gov (United States)

    Vangeleyn, Matthieu; Griffin, Paul F; Riis, Erling; Arnold, Aidan S

    2009-08-03

    We have realized a 4-beam pyramidal magneto-optical trap ideally suited for future microfabrication. Three mirrors split and steer a single incoming beam into a tripod of reflected beams, allowing trapping in the four-beam overlap volume. We discuss the influence of mirror angle on cooling and trapping, finding optimum efficiency in a tetrahedral configuration. We demonstrate the technique using an ex-vacuo mirror system to illustrate the previously inaccessible supra-plane pyramid MOT configuration. Unlike standard pyramidal MOTs both the pyramid apex and its mirror angle are non-critical and our MOT offers improved molasses free from atomic shadows in the laser beams. The MOT scheme naturally extends to a 2-beam refractive version with high optical access. For quantum gas experiments, the mirror system could also be used for a stable 3D tetrahedral optical lattice.

  1. A quantum delayed choice experiment

    CERN Document Server

    Peruzzo, Alberto; Brunner, Nicolas; Popescu, Sandu; O'Brien, Jeremy L

    2012-01-01

    Quantum systems exhibit particle-like or wave-like behaviour depending on the experimental apparatus they are confronted by. This wave-particle duality is at the heart of quantum mechanics, and is fully captured in Wheeler's famous delayed choice gedanken experiment. In this variant of the double slit experiment, the observer chooses to test either the particle or wave nature of a photon after it has passed through the slits. Here we report on a quantum delayed choice experiment, based on a quantum controlled beam-splitter, in which both particle and wave behaviours can be investigated simultaneously. The genuinely quantum nature of the photon's behaviour is tested via a Bell inequality, which here replaces the delayed choice of the observer. We observe strong Bell inequality violations, thus showing that no model in which the photon knows in advance what type of experiment it will be confronted by, hence behaving either as a particle or as wave, can account for the experimental data.

  2. The Right Delay

    NARCIS (Netherlands)

    Datadien, A.H.R.; Haselager, W.F.G.; Sprinkhuizen-Kuyper, I.G.

    2011-01-01

    Axonal conduction delays should not be ignored in simulations of spiking neural networks. Here it is shown that by using axonal conduction delays, neurons can display sensitivity to a specific spatio-temporal spike pattern. By using delays that complement the firing times in a pattern, spikes can ar

  3. HIGHLIGHTS LHC First Beam - Accelerating Science : 10 September 2008

    CERN Multimedia

    CERN Audiovisual Service

    2008-01-01

    First beam in the LHC - accelerating science A historic moment in the CERN Control Centre: the beam was successfully steered around the accelerator. Channel 1 : International Channel 2 : English guide A historic moment in the CERN Control Centre: the beam was successfully steered around the accelerator. Geneva, 10 September 2008. The first beam in the Large Hadron Collider at CERN1 was successfully steered around the full 27 kilometres of the world’s most powerful particle accelerator at 10h28 this morning. This historic event marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. “It’s a fantastic moment,” said LHC project leader Lyn Evans, “we can now look forward to a new era of understanding about the origins and evolution of the universe.” Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronized to under a billionth of a...

  4. Proportional directional valve based automatic steering system for tractors

    Institute of Scientific and Technical Information of China (English)

    Jin-yi LIU; Jing-quan TAN; En-rong MAO; Zheng-he SONG; Zhong-xiang ZHU‡

    2016-01-01

    Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3-position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressure-compensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative (PID) running on a 51-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoi-dal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods.

  5. Steering gameplay behavior in the interactive tag playground

    NARCIS (Netherlands)

    Delden, van Robby; Moreno, Alejandro; Poppe, Ronald; Reidsma, Dennis; Heylen, Dirk; Aarts, Emile; Ruyter, de Boris; Markopoulos, Panos; Loenen, van Evert; Wichert, Reiner; Schouten, Ben; Terken, Jacques; Kranenburg, van Rob; Ouden, den Elke; O'Hare, Gregory

    2014-01-01

    This paper deals with steering player behavior in the Interactive Tag Playground (ITP). The ITP, an ambient environment instrumented with contact-free sensor technology and ambient display capabilities, enhances the traditional game of tag by determining when a valid tag has been made and visualisin

  6. Steering Gameplay Behavior in the Interactive Tag Playground

    NARCIS (Netherlands)

    Van Delden, Robby; Moreno, Alejandro; Poppe, Ronald; Reidsma, Dennis; Heylen, Dirk K J

    2014-01-01

    This paper deals with steering player behavior in the Interactive Tag Playground (ITP). The ITP, an ambient environment instrumented with contact-free sensor technology and ambient display capabilities, enhances the traditional game of tag by determining when a valid tag has been made and visualisin

  7. Complex Education Systems: From Steering Change to Governance

    Science.gov (United States)

    Michel, Alain

    2016-01-01

    The theories and approaches of steering/monitoring a process of change within education systems have evolved over the last 20 years or so as a result of many factors such as globalisation and decentralisation, a faster pace of change, increasing expectations and demands from various stakeholders (parents, employers, teacher unions, etc.) and the…

  8. Analytic Steering: Inserting Context into the Information Dialog

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, Shawn J.; Calapristi, Augustin J.; Brown, Shyretha D.; Nakamura, Grant C.

    2011-10-23

    An analyst’s intrinsic domain knowledge is a primary asset in almost any analysis task. Unstructured text analysis systems that apply un-supervised content analysis approaches can be more effective if they can leverage this domain knowledge in a manner that augments the information discovery process without obfuscating new or unexpected content. Current unsupervised approaches rely upon the prowess of the analyst to submit the right queries or observe generalized document and term relationships from ranked or visual results. We propose a new approach which allows the user to control or steer the analytic view within the unsupervised space. This process is controlled through the data characterization process via user supplied context in the form of a collection of key terms. We show that steering with an appropriate choice of key terms can provide better relevance to the analytic domain and still enable the analyst to uncover un-expected relationships; this paper discusses cases where various analytic steering approaches can provide enhanced analysis results and cases where analytic steering can have a negative impact on the analysis process.

  9. Threats and protection for electronically-steered array radars

    NARCIS (Netherlands)

    Janssen, J.P.B.; Monni, S.; Maas, A.P.M.; Vliet, F.E. van

    2008-01-01

    Front-end power overload protection is a vital issue in any electro-magnetic sensor. The issues around active electronically-steered arrays are more recent and pose new threats. Different categories of threats can damage the sensitive electronics in the phased-array radar, like hostile high power

  10. DSPIC BASED POWER ASSISTED STEERING USING BRUSHLESS DIRECT CURRENT MOTOR

    Directory of Open Access Journals (Sweden)

    G. R.P. Lakshmi

    2013-01-01

    Full Text Available This study illustrates the Electrically Assisted power Steering (EAS using BLDC motor for a vehicle. Earlier the Electrically Assisted power Steering (EAS was implemented with DSP. This study shows the usage of a dsPIC to control the BLDC motor with an encoder. The BLDC motor here is driven by dsPIC through a three phase inverter system. IRAMS type of inverter is used which is cost efficient and space efficient. The dsPIC supplied with the input of the steering. In its higher capacity the vehicles speed controller acts as the assistance level controller for steering effort. At the lower capacity, the torque controller gives the effort level control. In reality this can be realized as torque sensor and vehicle sensor interfaced in the dsPIC. For actual implementation in the system, a dsPIC-based BLDC motor controller with three-phase inverter module is used with Hall-effect sensor feedback. It is designed in such a way that the driver assistance can be varied at any time without any difficulty.

  11. The Analysis of The Fault of Electrical Power Steering

    Directory of Open Access Journals (Sweden)

    Zhang Li Wen

    2016-01-01

    Full Text Available This paper analysis the common fault types of primary Electrical Power Steering system, meanwhile classify every fault. It provides the basis for further troubleshooting and maintenance. At the same time this paper propose a practical working principle of fault-tolerant, in order to make the EPS system more security and durability.

  12. Multifunctional Converter Drive for Automotive Electric Power Steering Systems

    NARCIS (Netherlands)

    Hackner, T.J.

    2013-01-01

    In this thesis it is shown that in the case of an automotive electric power steering system, critical pulse power loads can be decoupled from the power net with a storage element and a multifunctional converter. A multifunctional converter system is proposed because it uses the motor drive system as

  13. Interagency Advanced Power Group -- Steering group meeting minutes

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-18

    This document contains the draft meeting minutes of the Steering Group of the Interagency Advanced Power Group. Included are the discussions resulting from the presentation of working group reports and the results of a discussion of IAPG policies and procedures. In the appendix are the reports of the following working groups: Electrical, Mechanical, Solar, and Systems.

  14. Threats and protection for electronically-steered array radars

    NARCIS (Netherlands)

    Janssen, J.P.B.; Monni, S.; Maas, A.P.M.; Vliet, F.E. van

    2008-01-01

    Front-end power overload protection is a vital issue in any electro-magnetic sensor. The issues around active electronically-steered arrays are more recent and pose new threats. Different categories of threats can damage the sensitive electronics in the phased-array radar, like hostile high power el

  15. CLOSED FORM OF THE STEERED ELONGATED HERMITE-GAUSS WAVELETS

    NARCIS (Netherlands)

    Papari, Giuseppe; Campisi, Patrizio; Petkov, Nicolai

    2010-01-01

    We provide a closed form, both in the spatial and in the frequency domain, of a family of wavelets which arise from steering elongated Hermite-Gauss filters. These wavelets have interesting mathematical properties, as they form new dyadic families of eigenfunctions of the 2D Fourier transform, and

  16. The value of theoretical multiplicity for steering transitions towards sustainability

    NARCIS (Netherlands)

    Dewulf, A.; Termeer, C.J.A.M.; Pot, W.D.; Werkman, R.A.; Breeman, G.E.

    2009-01-01

    Transition management, as a theory of directing structural societal changes towards sustainable system innovations, has become a major topic in scientific research over the last years. In this paper we focus on the question how transitions towards sustainability can be steered, governed or managed,

  17. Mechanics of Flexible Needles Robotically Steered through Soft Tissue

    NARCIS (Netherlands)

    Misra, S.; Reed, K.B.; Schafer, B.W.; Ramesh, K.T.; Okamura, A.M.

    2010-01-01

    The tip asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. This enables robotic needle steering, which can be used in medical procedures to reach subsurface targets inaccessible by straight-line trajectories. However, accurate path planning

  18. A transverse emittance and acceptance measurement system in a low-energy beam transport line

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, H., E-mail: kashiwagi.hirotsugu@jaea.go.jp; Miyawaki, N.; Kurashima, S.; Okumura, S. [Department of Advanced Radiation Technology, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2014-02-15

    A transverse beam emittance and acceptance measurement system has been developed to visualize the relationship between the injected beam emittance and the acceptance of a cyclotron. The system is composed of a steering magnet, two pairs of slits to limit the horizontal and vertical phase-space, a beam intensity detector just behind the slits for the emittance measurement, and a beam intensity detector in the cyclotron for the acceptance measurement. The emittance is obtained by scanning the slits and measuring the beam intensity distribution. The acceptance is obtained by measuring the distribution of relative beam transmission by injecting small emittance beams at various positions in a transverse phase-space using the slits. In the acceptance measurement, the beam from an ion source is deflected to the defined region by the slits using the steering magnet so that measurable acceptance area covers a region outside the injection beam emittance. Measurement tests were carried out under the condition of accelerating a beam of {sup 16}O{sup 6+} from 50.2 keV to 160 MeV. The emittance of the injected beam and the acceptance for accelerating and transporting the beam to the entrance of the extraction deflector were successfully measured. The relationship between the emittance and acceptance is visualized by displaying the results in the same phase-plane.

  19. Immunization of Bos taurus steers with Babesia bovis recombinant antigens MSA-1, MSA-2c and 12D3.

    Science.gov (United States)

    Antonio Alvarez, J; Lopez, U; Rojas, C; Borgonio, V M; Sanchez, V; Castañeda, R; Vargas, P; Figueroa, J V

    2010-04-01

    The purpose of this research was to evaluate the recombinant proteins MSA-1, MSA-2c and 12D3 as a combined immunogen for cattle. Fifteen steers were randomly assigned into three groups of five animals each (I, II and III). On day 0, cattle in group I were injected with 50 microg each of rMSA-1, rMSA-2c and r12D3 with the adjuvant Montanide 75; cattle in Group II received adjuvant-PBS, and Group III were untreated controls. On day 14, cattle in Group I received a second injection of the three recombinant proteins in adjuvant and cattle in Group II again received adjuvant alone. On day 28, all groups of cattle were challenged with a field strain of Babesia bovis. After challenge, the experimental cattle were clinically and serologically monitored. Three of the five steers immunized with the combined recombinant B. bovis proteins seroconverted on day 14 post-immunization (P.I.) and the maximum titre was 1 : 1600. All five immunized steers presented strong seropositivity to B. bovis antigens at day 21 P.I. The prepatent periods of vaccinated cattle were delayed until day 10 post-challenge exposure versus 8 and 7 days in Groups II and III, respectively. Cattle in all groups had fever above 41 degrees C; the reduction in packed cell volume was not significantly different (P > 0.05) in vaccinated group I compared with Groups II and III (29% versus 26% and 31%, respectively). Treatment was required for one steer in the control group. During the period of the study, the weight of cattle in Groups I and II increased an average of 9 and 7 kg, whereas the weight of the control cattle was reduced on average 4 kg. Immunization with rMSA-1-rMSA-2c-r12D3 proteins was not sufficient to prevent clinical symptoms against challenge, but the immunologic response was sufficient to protect steers against a mild virulent strain of B. bovis.

  20. An Analytical Delay Model

    Institute of Scientific and Technical Information of China (English)

    MIN Yinghua; LI Zhongcheng

    1999-01-01

    Delay consideration has been a majorissue in design and test of high performance digital circuits. Theassumption of input signal change occurring only when all internal nodesare stable restricts the increase of clock frequency. It is no longertrue for wave pipelining circuits. However, previous logical delaymodels are based on the assumption. In addition, the stable time of arobust delay test generally depends on the longest sensitizable pathdelay. Thus, a new delay model is desirable. This paper explores thenecessity first. Then, Boolean process to analytically describe thelogical and timing behavior of a digital circuit is reviewed. Theconcept of sensitization is redefined precisely in this paper. Based onthe new concept of sensitization, an analytical delay model isintroduced. As a result, many untestable delay faults under thelogical delay model can be tested if the output waveforms can be sampledat more time points. The longest sensitizable path length is computedfor circuit design and delay test.

  1. Frequency dependent steering with backward leaky waves via photonic crystal interface layer.

    Science.gov (United States)

    Colak, Evrim; Caglayan, Humeyra; Cakmak, Atilla O; Villa, Alessandro D; Capolino, Filippo; Ozbay, Ekmel

    2009-06-08

    A Photonic Crystal (PC) with a surface defect layer (made of dimers) is studied in the microwave regime. The dispersion diagram is obtained with the Plane Wave Expansion Method. The dispersion diagram reveals that the dimer-layer supports a surface mode with negative slope. Two facts are noted: First, a guided (bounded) wave is present, propagating along the surface of the dimer-layer. Second, above the light line, the fast traveling mode couple to the propagating spectra and as a result a directive (narrow beam) radiation with backward characteristics is observed and measured. In this leaky mode regime, symmetrical radiation patterns with respect to the normal to the PC surface are attained. Beam steering is observed and measured in a 70 degrees angular range when frequency ranges in the 11.88-13.69 GHz interval. Thus, a PC based surface wave structure that acts as a frequency dependent leaky wave antenna is presented. Angular radiation pattern measurements are in agreement with those obtained via numerical simulations that employ the Finite Difference Time Domain Method (FDTD). Finally, the backward radiation characteristics that in turn suggest the existence of a backward leaky mode in the dimer-layer are experimentally verified using a halved dimer-layer structure.

  2. Study on a New Steering Mechanism for Point-the-Bit Rotary Steerable System

    Directory of Open Access Journals (Sweden)

    Yuanzhi Li

    2014-02-01

    Full Text Available This paper presents a novel steering mechanism embedded in a point-the-bit rotary steerable system (RSS for oilfield exploitation. The new steering mechanism adopts a set of universal joints to alleviate the high alternative strain on drilling mandrel and employs a specially designed planetary gear small tooth number difference (PGSTD to achieve directional steering. Its principle and characteristics are explained and examined through a series of analyses. First, the eccentric displacement vector of the offset point on the drilling mandrel is formulated and kinematic solutions are established. Next, structural design for the new steering mechanism is addressed. Then, procedures and program architectures for simulating offset state of the drilling mandrel and motion trajectory of the whole steering mechanism are presented. After that, steering motion simulations of the new steering mechanism for both 2D and 3D well trajectories are then performed by combining LabVIEW and SolidWorks. Finally, experiments on the steering motion control of the new steering mechanism prototype are carried out. The simulations and experiments reveal that the steering performance of the new steering mechanism is satisfied. The research can provide good guidance for further research and engineering application of the point-the-bit RSS.

  3. Development of active rear steer actuator. Development of four wheel steer actuator for active safety; Active rear steer actuator no kaihatsu. Yobo anzen ni muketa 4WS actuator no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, T. [Aisin Seiki Co. Ltd., Aichi (Japan)

    1997-10-01

    Recently, ecology, energy saving and safety have become important issues. And Active Safety is spotlighted in vehicle control area. Many researches and developments on four wheel steer system have been done to improve vehicle stability. We have developed the Active Rear Steer system with electromechanical Actuator, which is mass-productive, compact, and high response and durable. 10 figs., 5 tabs.

  4. Development of a Mechanism for Measuring Forces and Aligning Moment Acting on the Steering Wheels of a Four-Wheel Vehicle

    Directory of Open Access Journals (Sweden)

    A Hajiahmad

    2014-09-01

    Full Text Available In this paper, a low-cost dynamometer for rolling, steered wheels is described. The dynamometer was constructed to determine whether such an instrumented mechanism was practical. Four S-beam load cells, an Opto-counter and a potentiometer were used to obtain all moments, and forces using dynamic and kinematic analysis. Minimal simplifying assumptions considered for the required calculations. Overturning, aligning and rolling resistance moments besides vertical force are directly measured by the load cells. The Opto-counter detects wheel angular velocity and the potentiometer was used to measure the steering angle. The results showed that the mechanism was very well calibrated with a coefficient of determination of over 0.99 and can be used to define wheel dynamic behavior.

  5. Time of daily supplementation for steers grazing dormant intermediate wheatgrass pasture.

    Science.gov (United States)

    Barton, R K; Krysl, L J; Judkins, M B; Holcombe, D W; Broesder, J T; Gunter, S A; Beam, S W

    1992-02-01

    To compare the effects of time of daily protein supplementation on grazing behavior, forage intake, digesta kinetics, ruminal fermentation, and serum hormones and metabolites, 12 ruminally cannulated Holstein steers (449 and 378 kg average initial and final BW, respectively) were allotted to three groups. Treatments consisted of CON = no supplement, AM = cottonseed meal (.25% of BW) at 0600, and PM = cottonseed meal (.25% of BW) at 1200. Steers grazed a dormant (1.1% N) intermediate wheatgrass (Thinopyrum intermedium Host) pasture. Sampling trials occurred in December, January, and February. Supplementation altered (P = .01) time spent grazing; CON steers grazed approximately 1.5 h longer than supplemented steers. Supplemented steers lost less (P = .02) BW (-40 kg) than CON steers (-75 kg) did. Supplementation did not alter (P greater than .15) forage OM intake; however, total OM intake was greater (P = .01) for supplemented steers (22.3 g/kg of BW) than for CON (18.4 g/kg of BW) steers. Supplementation did not affect (P greater than .15) digesta kinetics. Extent of in situ NDF (96 h) and rate (%/h) of disappearance for supplemented steers was greater (P = .01) than for CON steers. Across all periods, ruminal NH3 N and total VFA concentrations were lower (P = .01) for CON steers than for supplemented steers. Serum insulin (ng/mL) concentration was lower (P = .03) and concentration of serum growth hormone (ng/mL) was higher (P = .02) for CON steers than for supplemented steers. Cottonseed meal supplementation enhanced utilization of intermediate wheatgrass; however, supplementation time had minimal effects on the variables measured.

  6. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  7. High power, fast, microwave components based on beam generated plasmas

    Science.gov (United States)

    Manheimer, W. M.; Fernsler, R. F.; Gitlin, M. S.

    1998-10-01

    It is shown that the agile mirror plasma, under development as a device to simply and cheaply give electronic steering to microwave beams, also has application as a fast, electronically controlled, high power reflector, or phase shifter. In a radar system, this can lead to such applications as pulse to pulse polarization agility and electronic control of antenna gain, as well as to innovative approaches to high power millimeter wave circulators. The basic theory of the enhanced glow plasma is also developed.

  8. Delayed emergence after anesthesia.

    Science.gov (United States)

    Tzabazis, Alexander; Miller, Christopher; Dobrow, Marc F; Zheng, Karl; Brock-Utne, John G

    2015-06-01

    In most instances, delayed emergence from anesthesia is attributed to residual anesthetic or analgesic medications. However, delayed emergence can be secondary to unusual causes and present diagnostic dilemmas. Data from clinical studies is scarce and most available published material is comprised of case reports. In this review, we summarize and discuss less common and difficult to diagnose reasons for delayed emergence and present cases from our own experience or reference published case reports/case series. The goal is to draw attention to less common reasons for delayed emergence, identify patient populations that are potentially at risk and to help anesthesiologists identifying a possible cause why their patient is slow to wake up.

  9. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    2015-01-01

    This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...... it was developed in the image of the industrial society and based on a closed classroom. Now with the digital media and wireless networks the classroom is opened and the old way of organizing teaching has become inadequate: The students are disturbed by the new media, instead of learning through them. Inspired...... by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME...

  10. Detailed field test of yaw-based wake steering

    Science.gov (United States)

    Fleming, P.; Churchfield, M.; Scholbrock, A.; Clifton, A.; Schreck, S.; Johnson, K.; Wright, A.; Gebraad, P.; Annoni, J.; Naughton, B.; Berg, J.; Herges, T.; White, J.; Mikkelsen, T.; Sjöholm, M.; Angelou, N.

    2016-09-01

    This paper describes a detailed field-test campaign to investigate yaw-based wake steering. In yaw-based wake steering, an upstream turbine intentionally misaligns its yaw with respect to the inflow to deflect its wake away from a downstream turbine, with the goal of increasing total power production. In the first phase, a nacelle-mounted scanning lidar was used to verify wake deflection of a misaligned turbine and calibrate wake deflection models. In the second phase, these models were used within a yaw controller to achieve a desired wake deflection. This paper details the experimental design and setup. All data collected as part of this field experiment will be archived and made available to the public via the U.S. Department of Energy's Atmosphere to Electrons Data Archive and Portal.

  11. Mechanics of Thin Strip Steering in Hot Rolling

    Science.gov (United States)

    Jiang, Zhengyi; Tieu, Kiet A.

    2004-06-01

    The hot rolling of thin strip can result in several problems in hot rolling, for instance, the control of strip steering, strip shape and flatness and surface roughness etc. Therefore, the hot rolling of thin strip brings out a requirement of innovative technologies such as the extended control of shape and flatness, steering control and reduction of load by roll gap lubrication. In this paper, the authors focus on the analysis of thin strip snaking movement, as well as solve the related problems such as the shape and flatness due to a larger reduction applied when the strip is thinner. A finite element method was used to simulate this nonsymmetricity rolling considering the non-uniform reduction along the strip width. The calculated spread is compared with the measured values obtained from the rolling mill in laboratory and the friction effect is also discussed.

  12. Robust autopilot with wave filter for ship steering

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-zhou; XU Han-zhen

    2006-01-01

    Research was done to overcome traditional problems associated with automatic steering systems of a ship in a seaway. A ship's dynamic model with wave disturbances was built and a wave filter was designed by means of an extended states observer (ESO). The model estimated the low frequency motion component from a heading measurement corrupted by colorednoise, so back-and-forth steering caused by high frequency wave disturbances was avoided. At the same time, a robust autopilot system,designed by variable structure control theory, was presented. Simulation results achieved in dangerous sea status show that the wave filter works very well and the autopilot has strong robustness to environmental disturbances and model perturbation, and more importantly, the frequency of rudder adjustments is reduced noticeably.

  13. Predictive control and identification: Applications to steering dynamics

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela

    1996-01-01

    The main objective of the present thesis is to enhance insight into predictive controller design and identification in connection with steering dynamics. In Chapter 2, the dynamics of ship steering are reviewed. Models of different complexity, suitable for control systems design are presented....... The influence of wind, waves and currents on the chip motions are also discussed. Chapter 3 deals with the model reduction problem. Some basic concepts are explained, due to their role in the reduction of the dynamic models. Two model reductions techniques, based on singular values, are described....... The theoretical properties of these methods are studied and their performance is examined via simulation on a stochastic linear Mariner Class Vessel model. In Chapter 4, the attention is focused on the derivation of an extended GPC. This extended strategy implies a generalization of the model structure...

  14. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael Eric

    2016-01-01

    it was developed in the image of the industrial society and based on a closed classroom. Now with the digital media and wireless networks the classroom is opened and the old way of organizing teaching has become inadequate: The students are disturbed by the new media, instead of learning through them. Inspired......This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...... by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME...

  15. Assessing Visual Delays using Pupil Oscillations

    Science.gov (United States)

    Mulligan, Jeffrey B.

    2012-01-01

    Stark (1962) demonstrated vigorous pupil oscillations by illuminating the retina with a beam of light focussed to a small spot near the edge of the pupil. Small constrictions of the pupil then are sufficient to completely block the beam, amplifying the normal relationship between pupil area and retinal illuminance. In addition to this simple and elegant method, Stark also investigated more complex feedback systems using an electronic "clamping box" which provided arbitrary gain and phase delay between a measurement of pupil area and an electronically controlled light source. We have replicated Stark's results using a video-based pupillometer to control the luminance of a display monitor. Pupil oscillations were induced by imposing a linear relationship between pupil area and display luminance, with a variable delay. Slopes of the period-vs-delay function for 3 subjects are close to the predicted value of 2 (1.96-2.39), and the implied delays range from 254 to 376 508 to 652 milliseconds. Our setup allows us to extend Stark's work by investigating a broader class of stimuli.

  16. Planning analysis and political steering with New Public Management

    DEFF Research Database (Denmark)

    Sager, Tore Øivin; Sørensen, Claus Hedegaard

    2011-01-01

    of interviews sheds light on the apparent paradox that parliamentarians accept delegation of highway investment decisions despite their profound scepticism to the cost-benefit analyses and impact calculations that are essential to management by objectives and results, which was to give them continued political...... by the Government. The political concentration on strategic steering, the concomitant delegation, and management by objectives and results are central components of New Public Management....

  17. Modeling the behavior of the helmsman steering a ship

    Science.gov (United States)

    Veldhuyzen, W.; Stassen, H. G.

    1973-01-01

    A supertanker is considered as a nonlinear system which responds very slowly to changes in the rudder position. Moreover this type of ship is often unstable in loaded condition. In order to model the helmsman's behavior, a number of tests were performed using a ship maneuvering simulator. The trained subjects had to steer a 200,000 tons tanker along a varying course. The results obtained from these trials are presented.

  18. Planning analysis and political steering with New Public Management

    DEFF Research Database (Denmark)

    Sager, Tore Øivin; Sørensen, Claus Hedegaard

    2011-01-01

    of interviews sheds light on the apparent paradox that parliamentarians accept delegation of highway investment decisions despite their profound scepticism to the cost-benefit analyses and impact calculations that are essential to management by objectives and results, which was to give them continued political...... by the Government. The political concentration on strategic steering, the concomitant delegation, and management by objectives and results are central components of New Public Management....

  19. Erasmus Darwin's improved design for steering carriages and cars.

    Science.gov (United States)

    King-Hele, Desmond

    2002-01-01

    Carriage journeys in England during the eighteenth century were notoriously dangerous. Rutted and pot-holed roads exacerbated the deficiencies in steering, springing and stability. In 1758 the young Dr. Erasmus Darwin (1731-1802; F. R. S. 1761) was travelling about 10,000 miles a year in visits to patients from his house at Lichfield. To alleviate the danger and discomfort of his journey, he developed a design for improved carriage steering and stability, which he road-tested over 20,000 miles on two carriages. In 1765 Richard Lovell Edgeworth (1744-1817; F. R. S. 1718) heard about Darwin's design, urged the Society of Arts to enquire about it, and then visited Darwin himself. With the aid of manuscripts from the Archive of the Royal Society of Arts and elsewhere, I offer a reconstruction of Darwin's improved method of steering, which relies on four jointed rods, initially in the form of an isosceles trapezium. The mechanism was reinvented more than 50 years later, and came to be used widely in early modern cars.

  20. Volume monogamy of quantum steering ellipsoids for multiqubit systems

    Science.gov (United States)

    Cheng, Shuming; Milne, Antony; Hall, Michael J. W.; Wiseman, Howard M.

    2016-10-01

    The quantum steering ellipsoid can be used to visualize 2-qubit states, and thus provides a generalization of the Bloch picture for the single qubit. Recently, a monogamy relation for the volumes of steering ellipsoids has been derived for pure 3-qubit states and shown to be stronger than the celebrated Coffman-Kundu-Wootters inequality. We first demonstrate the close connection between this volume monogamy relation and the classification of pure 3-qubit states under stochastic local operations and classical communication. We then show that this monogamy relation does not hold for general mixed 3-qubit states and derive a weaker monogamy relation that does hold for such states. We also prove a volume monogamy relation for pure 4-qubit states (further conjectured to hold for the mixed case), and generalize our 3-qubit inequality to n qubits. Finally, we study the effect of noise on the quantum steering ellipsoid and find that the volume of any 2-qubit state is nonincreasing when the state is exposed to arbitrary local noise. This implies that any volume monogamy relation for a given class of multiqubit states remains valid under the addition of local noise. We investigate this quantitatively for the experimentally relevant example of isotropic noise.

  1. Imperfection Insensitivity Analyses of Advanced Composite Tow-Steered Shells

    Science.gov (United States)

    Wu, K. Chauncey; Farrokh, Babak; Stanford, Bret K.; Weaver, Paul M.

    2016-01-01

    Two advanced composite tow-steered shells, one with tow overlaps and another without overlaps, were previously designed, fabricated and tested in end compression, both without cutouts, and with small and large cutouts. In each case, good agreement was observed between experimental buckling loads and supporting linear bifurcation buckling analyses. However, previous buckling tests and analyses have shown historically poor correlation, perhaps due to the presence of geometric imperfections that serve as failure initiators. For the tow-steered shells, their circumferential variation in axial stiffness may have suppressed this sensitivity to imperfections, leading to the agreement noted between tests and analyses. To investigate this further, a numerical investigation was performed in this study using geometric imperfections measured from both shells. Finite element models of both shells were analyzed first without, and then, with measured imperfections that were then, superposed in different orientations around the shell longitudinal axis. Small variations in both the axial prebuckling stiffness and global buckling load were observed for the range of imperfections studied here, which suggests that the tow steering, and resulting circumferentially varying axial stiffness, may result in the test-analysis correlation observed for these shells.

  2. Visual-Motor Control of Steering and Awareness of Performance

    Directory of Open Access Journals (Sweden)

    Callum Mole

    2012-05-01

    Full Text Available In order to carry out skilled, visually guided actions, humans need to be able to use feedback to monitor and adjust performance. Such feedback can be relatively low level, with some motor commands being recalibrated rapidly based on visual feedback with little cognitive awareness (eg, Mon-Williams and Murray 2000. In tasks such as driving, however, awareness of performance could be important for making strategic adjustments in order to respond to road conditions. To investigate whether participants could accurately gauge steering performance, we used a simulated driving scenario. Participants (n=30 were required to steer around a series of bends and stay within a central marked zone. In order to alter the task demands, the speed of travel (fast/slow and the width of the zone (narrow/wide were manipulated. After each bend the participants made an explicit percentage judgment of time spent within the required zone. The mean group steering results showed that performance was worst for faster speeds and narrower zones, and this pattern was matched in the awareness judgements. Closer inspection of the data, however, showed that at an individual level these judgements often failed to capture trial performance and were often merely influenced by the visible task characteristics (eg, fast and narrow trial. This suggests that participants may erroneously rely on salient cues about task characteristics to assess performance if direct feedback is weak. This has important implications for driving since individuals may be failing to respond to situation characteristics that actually make performance worse.

  3. American Dream Delayed

    DEFF Research Database (Denmark)

    Khorunzhina, Natalia; Miller, Robert A.

    This paper investigates the delay in homeownership and a subsequent reduction in homeownership rate observed over the past decades. We focus on the delay in giving birth to children and increased labor market participation as contributing factors to homeownership dynamics for prime-age female hou...

  4. A preliminary study of the feasibility of using superconducting quarter-wave resonators for accelerating high intensity proton beams

    Institute of Scientific and Technical Information of China (English)

    YANG Liu; LU Xiang-Yang; QUAN Sheng-Wen; YAO Zhong-Yuan; LUO Xing; ZHOU Kui

    2012-01-01

    The superconducting (SC) cavities currently used for the acceleration of protons at a low velocity range are based on half-wave resonators.Due to the rising demand on high current,the issue of beam loading and space-charge problems has arisen.Qualities of low cost and high accelerating efficiency are required for SC cavities,which are properly fitted by using SC quarter-wave resonators (QWR).We propose a concept of using QWRs with frequency 162.5 MHz to accelerate high current proton beams.The main factor limiting SC QWRs being applied to high current proton beams is vertical beam steering,which is dominantly caused by the magnetic field on axis.In this paper,we intend to analyze steering and eliminate it to verify the qualification of using QWRs to accelerate high intensity proton beams.

  5. Postweaning performance and carcass merit of F1 steers sired by Brahman and alternative subtropically adapted breeds.

    Science.gov (United States)

    Franke, D E

    1997-10-01

    Comparisons were made among F1 steers sired by Brahman and alternative subtropically adapted breeds of bulls for feedlot and carcass traits when steers were produced from Angus- and Hereford-type dams. Brahman-derivative breeds included Brangus, Beefmaster, and Santa Gertrudis. Brangus- and Beefmaster-sired steers weighed less at slaughter, whereas carcasses of Brangus- and Santa Gertrudis-sired steers had more marbling than those of Brahman-sired steers. Brahman-sired steer carcasses had greater longissimus muscle area than carcasses of Santa Gertrudis-sired steers. Other Zebu breeds compared to Brahman were Boran, Gir, Indu-Brazil, Nellore, Red Brahman, and Sahiwal. Steers by Brahman sires had higher slaughter weights than steers by Boran, Gir, Nellore, or Sahiwal sires. Hot carcass weights of Brahman-sired steers were also higher than those of Boran- and Sahiwal-sired steers. Steer carcasses by Brahman sires had greater longissimus muscle area than those of steers by Sahiwal sires. Non-Zebu breeds included Tuli and Senepol. Steers by Tuli sires grew slower, had lower slaughter weights, and their carcasses weighed less than those of Brahman-sired steers. Brahman-sired steer carcasses had greater longissimus muscle area but less marbling than carcasses of Tuli-sired steers. These data suggest that steers by Brahman sires have an advantage for slaughter weight over steers by Brangus, Beefmaster, Boran, Gir, Nellore, Sahiwal, and Tuli sires, but their carcasses are at a disadvantage for marbling score compared with those by Brangus, Boran, Nellore, and Tuli sires.

  6. Multiobjective Optimization of Steering Mechanism for Rotary Steering System Using Modified NSGA-II and Fuzzy Set Theory

    Directory of Open Access Journals (Sweden)

    Hongtao Li

    2015-01-01

    Full Text Available Due to the complicated design process of gear train, optimization is a significant approach to improve design efficiency. However, the design of gear train is a complex multiobjective optimization with mixed continuous-discrete variables under numerous nonlinear constraints, and conventional optimization algorithms are not suitable to deal with such optimization problems. In this paper, based on the established dynamic model of steering mechanism for rotary steering system, the key component of which is a planetary gear set with teeth number difference, the optimization problem of steering mechanism is formulated to achieve minimum dynamic responses and outer diameter by optimizing structural parameters under geometric, kinematic, and strength constraints. An optimization procedure based on modified NSGA-II by incorporating dynamic crowding distance strategies and fuzzy set theory is applied to the multiobjective optimization. For comparative purpose, NSGA-II is also employed to obtain Pareto optimal set, and dynamic responses of original and optimized designs are compared. The results show the optimized design has better dynamic responses with minimum outer diameter and the response decay decreases faster. The optimization procedure is feasible to the design of gear train, and this study can provide guidance for designer at the preliminary design phase of mechanical structures with gear train.

  7. Effects of saponin extracts on air emissions from steers.

    Science.gov (United States)

    Li, W; Powers, W

    2012-11-01

    A series of experiments were conducted to quantify the effects of saponin extracts from Quillaja saponaria Molina (QS), Yucca schidigera Roezl ex Ortgies (YS), and Camellia sinensis (L.) Kuntze (TS) on gaseous emissions from steers (Bos taurus). During Exp. 1, a control diet [C1, corn (Zea mays L.) and corn silage basal diet] was compared with YS1 (C1 + 0.64% dietary DM of YS) and QS1 (C1 + 1.5% dietary DM of QS), with 4 replicates per treatment. During Exp. 2, the control diet (C2, corn and corn silage basal diet) was compared with TS2 (C2 + 0.25% dietary DM of TS). Product inclusion levels were established to provide the same concentration of saponin compounds across studies for Exp. 1 and 2. Experiment 3 compared C3 (corn and corn silage basal diet), QS3 (C3 + 1.5% QS), YS3 (C3 + 1.5% YS), and TS3 (C3 + 0.5% TS). Holstein steers (n = 12) at initial BW of 354 ± 10 kg (Exp. 1), 429 ± 10 kg (Exp. 2), 382 ± 16 kg (Period 1, Exp. 3) and 400 ± 12 kg (Period 2, Exp. 3) were individually housed in environmental rooms for 22 d per study. Gaseous emissions including methane (CH(4)), ammonia (NH(3)), and nitrous oxide (N(2)O) were monitored in room exhaust air. No differences in DMI (7.54 ± 0.09 kg) and ADG (1.16 ± 0.19 kg) were observed in Exp. 1 (P > 0.05). Adding TS2 to the diet improved DMI in Exp. 2 (8.94 kg in TS2 vs. 8.53 in C2; P < 0.01), whereas ADG was not affected by diet. During Exp. 3, steers fed the TS3 diet ate less (6.36 kg/d) and gained less BW (0.31 kg/d) compared with the other 3 treatments. Saponin inclusion did not alter daily CH(4) emission per unit DMI (13.17, 10.90, and 13.21 g/kg DMI, for Exp. 1, 2, and 3, respectively). Emissions of NH(3) per unit N intake were not affected by diets in Exp. 1 (134.89 mg/g N consumed) and Exp. 3 (134.99 mg/g N consumed). Feeding TS2 reduced NH(3) emission per unit of N consumed by 30% compared with C2 (P < 0.01). Feeding up to 0.5% of TS failed to reduce CH(4) emissions without impairing steer growth. Nitrous

  8. Non-linearly phased 2-D array transducers arranged on a cylindrical-polar grid for real time guided wave mode control and steering

    Science.gov (United States)

    Kannajosyula, H.; Lissenden, C. J.; Rose, J. L.

    2012-05-01

    Ultrasonic guided wave mode control and steering using phased array transducers (PATs) is studied. A PAT with elements arranged on a cylindrical-polar grid is proposed to overcome the problem of large side-lodes associated with a rectangular grid PAT. The PAT is visualized as a spatio-temporal filter to calculate phase delays. Wavenumber bands resulting from the radial rows enable constructive interfere only in the vicinity of the desired wavenumber and angle of propagation. Finite element simulations are presented to study PAT performance.

  9. Electronic differential control of 2WD electric vehicle considering steering stability

    Science.gov (United States)

    Hua, Yiding; Jiang, Haobin; Geng, Guoqing

    2017-03-01

    Aiming at the steering wheel differential steering control technology of rear wheel independent driving electric wheel, considering the assisting effect of electronic differential control on vehicle steering, based on the high speed steering characteristic of electric wheel car, the electronic differential speed of auxiliary wheel steering is also studied. A yaw moment control strategy is applied to the vehicle at high speed. Based on the vehicle stability reference value, yaw rate is used to design the fuzzy controller to distribute the driving wheel torque. The simulation results show that the basic electronic differential speed function is realized based on the yaw moment control strategy, while the vehicle stability control is improved and the driving safety is enhanced. On the other hand, the torque control strategy can also assist steering of vehicle.

  10. Robust Adaptive Beamforming Based on Steering Vector Estimation via Semidefinite Programming Relaxation

    CERN Document Server

    Khabbazibasmenj, Arash; Hassanien, Aboulnasr

    2010-01-01

    We develop a new approach to robust adaptive beamforming in the presence of signal steering vector errors. Since the signal steering vector is known imprecisely, its presumed (prior) value is used to find a more accurate estimate of the actual steering vector, which then is used for obtaining the optimal beamforming weight vector. The objective for finding such an estimate of the actual signal steering vector is the maximization of the beamformer output power, while the constraints are the normalization condition and the requirement that the estimate of the steering vector does not converge to an interference steering vector. Our objective and constraints are free of any design parameters of non-unique choice. The resulting optimization problem is a non-convex quadratically constrained quadratic program, which is NP hard in general. However, for our problem we show that an efficient solution can be found using the semi-definite relaxation technique. Moreover, the strong duality holds for the proposed problem ...

  11. Status of RHIC head-on beam-beam compensation project

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.; Anerella, M.; Beebe, E.; Bruno, D.; Gassner, D.M.; Gu, X.; Gupta, R.C.; Hock, J.; Jain, A.K.; Lambiase, R.; Liu, C.; Luo, Y.; Mapes, M.; Montag, C.; Oerter, B.; Okamura, M.; Pikin, A.I.; Raparia, D.; Tan, Y.; Than, R.; Thieberger, P.; Tuozzolo, J.; Zhang, W.

    2011-03-28

    Two electron lenses are under construction for RHIC to partially compensate the head-on beam-beam effect in order to increase both the peak and average luminosities. The final design of the overall system is reported as well as the status of the component design, acquisition, and manufacturing. An overview of the RHIC head-on beam-beam compensation project is given in [1], and more details in [2]. With 2 head-on beam-beam interactions in IP6 and IP8, a third interaction with a low-energy electron beam is added near IP10 to partially compensate the the head-on beam-beam effect. Two electron lenses are under construction, one for each ring. Both will be located in a region common to both beams, but each lens will act only on one beam. With head-on beam-beam compensation up to a factor of two improvement in luminosity is expected together with a polarized source upgrade. The current RHIC polarized proton performance is documented in Ref. [4]. An electron lens (Fig. 1) consists of an DC electron gun, warm solenoids to focus the electron beam during transport, a superconducting main solenoid in which the interaction with the proton beam occurs, steering magnets, a collector, and instrumentation. The main developments in the last year are given below. The experimental program for polarized program at 100 GeV was expected to be finished by the time the electron lenses are commissioned. However, decadal plans by the RHIC experiments STAR and PHENIX show a continuing interest at both 100 GeV and 250 GeV, and a larger proton beam size has been accommodated in the design (Tab. 1). Over the last year beam and lattice parameters were optimized, and RHIC proton lattices are under development for optimized electron lens performance. The effect of the electron lens magnetic structure on the proton beam was evaluated, and found to be correctable. Experiments were done in RHIC and the Tevatron.

  12. The influence of grid positioning on the beam optics in the neutral beam injectors for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Veltri, Pierluigi, E-mail: pierluigi.veltri@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, Padova (Italy); INFN—Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro, Padova (Italy); Agostinetti, Piero; Marcuzzi, Diego; Sartori, Emanuele; Serianni, Gianluigi [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, Padova (Italy)

    2016-06-15

    Neutral beam injectors are routinely used to increase the ion temperature in magnetically confined plasmas. Typically, the beam is produced by neutralizing a bundle of hundreds of ion beamlets, energized in a multi-grid multi-stage accelerator. Precise aiming of each beamlet is required in order to focus the full beam to the plasma, avoiding any interception with beamline surfaces and with the beam duct. This paper describes the effects of grid in-plane and out-of-plane displacements (mispositioning, thermal expansion, grid tilting, etc…) in the case of the MITICA electrostatic accelerator, which is the full scale prototype of the ITER heating neutral beam injector. Various simulations have been carried out with the OPERA 3D code, by self-consistently simulating the beam charged particles travelling in an externally applied electric and magnetic field. The accelerator grids act like a series of electrostatic lenses, and produce a net deflection of the particles when one or more grids are offset. The numerical simulations were used to evaluate the “steering constant” of each grid and also showed that the linear superposition of effects was applicable, multiple causes of mispositioning are combined and used to quantify the overall effect in terms of beam misalignment.

  13. Logic and control module for the Fermilab booster beam damper

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, B.R.

    1977-01-01

    A logic and control module is included in the electronic system of the booster superdamper. This module produces a 9-bit digital word that controls the delay of beam bunch position information in the Fermilab booster synchrotron so that it arrives at the damping electrodes at the same time as the bunch of beam to be corrected. This delay word generator also has an output feature that only allows delay time decreases as the booster synchrotron frequency program increases monotonically. Such a feature guards against low-index incidental FM from affecting the delay computations.

  14. Cycling around a curve: the effect of cycling speed on steering and gaze behavior.

    Directory of Open Access Journals (Sweden)

    Pieter Vansteenkiste

    Full Text Available Although it is generally accepted that visual information guides steering, it is still unclear whether a curvature matching strategy or a 'look where you are going' strategy is used while steering through a curved road. The current experiment investigated to what extent the existing models for curve driving also apply to cycling around a curve, and tested the influence of cycling speed on steering and gaze behavior. Twenty-five participants were asked to cycle through a semicircular lane three consecutive times at three different speeds while staying in the center of the lane. The observed steering behavior suggests that an anticipatory steering strategy was used at curve entrance and a compensatory strategy was used to steer through the actual bend of the curve. A shift of gaze from the center to the inside edge of the lane indicates that at low cycling speed, the 'look where you are going' strategy was preferred, while at higher cycling speeds participants seemed to prefer the curvature matching strategy. Authors suggest that visual information from both steering strategies contributes to the steering system and can be used in a flexible way. Based on a familiarization effect, it can be assumed that steering is not only guided by vision but that a short-term learning component should also be taken into account.

  15. Cycling around a curve: the effect of cycling speed on steering and gaze behavior.

    Science.gov (United States)

    Vansteenkiste, Pieter; Van Hamme, David; Veelaert, Peter; Philippaerts, Renaat; Cardon, Greet; Lenoir, Matthieu

    2014-01-01

    Although it is generally accepted that visual information guides steering, it is still unclear whether a curvature matching strategy or a 'look where you are going' strategy is used while steering through a curved road. The current experiment investigated to what extent the existing models for curve driving also apply to cycling around a curve, and tested the influence of cycling speed on steering and gaze behavior. Twenty-five participants were asked to cycle through a semicircular lane three consecutive times at three different speeds while staying in the center of the lane. The observed steering behavior suggests that an anticipatory steering strategy was used at curve entrance and a compensatory strategy was used to steer through the actual bend of the curve. A shift of gaze from the center to the inside edge of the lane indicates that at low cycling speed, the 'look where you are going' strategy was preferred, while at higher cycling speeds participants seemed to prefer the curvature matching strategy. Authors suggest that visual information from both steering strategies contributes to the steering system and can be used in a flexible way. Based on a familiarization effect, it can be assumed that steering is not only guided by vision but that a short-term learning component should also be taken into account.

  16. Modeling, Validation, and Control of Electronically Actuated Pitman Arm Steering for Armored Vehicle

    Directory of Open Access Journals (Sweden)

    Vimal Rau Aparow

    2016-01-01

    Full Text Available In this study, 2 DOF mathematical models of Pitman arm steering system are derived using Newton’s law of motion and modeled in MATLAB/SIMULINK software. The developed steering model is included with a DC motor model which is directly attached to the steering column. The Pitman arm steering model is then validated with actual Pitman arm steering test rig using various lateral inputs such as double lane change, step steer, and slalom test. Meanwhile, a position tracking control method has been used in order to evaluate the effectiveness of the validated model to be implemented in active safety system of a heavy vehicle. The similar method has been used to test the actual Pitman arm steering mechanism using hardware-in-the-loop simulation (HILS technique. Additional friction compensation is added in the HILS technique in order to minimize the frictional effects that occur in the mechanical configuration of the DC motor and Pitman arm steering. The performance of the electronically actuated Pitman arm steering system can be used to develop a firing-on-the-move actuator (FOMA for an armored vehicle. The FOMA can be used as an active safety system to reject unwanted yaw motion due to the firing force.

  17. EVALUATION OF A CONCEPTUAL VEHICLE STEERING SYSTEM FOR INDEPENDENT WHEEL CONTROL

    Directory of Open Access Journals (Sweden)

    Ryszard BUCHALIK

    2017-03-01

    Full Text Available This paper presents a brief description of an unconventional steering system involving electronic stability control and its influence on vehicle motion. The proposed configuration enables individual changes in steering angle for each single wheel, in contrast to the mechanical linkage solution. An analysis of vehicle behaviour during emergency braking on a heterogeneous surface is conducted, especially with regard to the undesirable rotation of the vehicle body. The benefits of using this active steering system, implemented in the steer-by-wire mode, are characterized, while the problems for further consideration and the potential benefits of such a solution are described.

  18. A Method for Eliminating Beam Steering Error for the Modulated Absorption-Emission Thermometry Technique

    Science.gov (United States)

    2014-01-01

    from the I2 signal. Self described how silicon photoconductive diodes were more stable and had higher quantum efficiency than photomultiplier tubes...100-1000 psia Two-color 750, 950 W-strip lamp Silicon diodes +/- 25K Paul-Self, 1989 H2/CO-O2 Hencken- type 1 atm 766.5 Quartz- Halogen Lamp

  19. A CMOS UWB transmitter with Vivaldi Array for Ultra-fast Beam steering microwave radar

    National Research Council Canada - National Science Library

    De Oliveira, Alexandre M; Ascama, Héctor D. O; Hiramatsu, Roberto K; Kofuji, Sérgio T; Perotoni, Marcelo B; Justo, João F

    2013-01-01

    This work presents a new Ultra Wide Band (UWB) beamforming fifth-order derivative Gaussian pulse transmitter with dual small Vivaldi antennas for remote acquisition of vital signals in impulse radar applications...

  20. Low Cost High Performance Phased Array Antennas with Beam Steering Capabilities

    Science.gov (United States)

    2009-12-01

    licensed use limited to: UNIV OF HAWAII LIBRARY. Downloaded on June 18.2010 at 22:19:39 UTC from IEEE Xplore Restrictions apply. 4W IEEE MICROWAVE...39 UTC from IEEE Xplore . Restrictions apply. ISKANDER el at.: COAXIAL CONTINUOUS TRANSVERSE STUB (CTS) ARRAY 4’) I S1 l(simjlated) = • and S11...22:19:39 UTC from IEEE Xplore Restrictions apply 2180 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION. VOL. 52. NO 8. AUGUST 2004 1 4 1 2 1 0 08

  1. Multi-Mode FMCW Radar Array with Independent Digital Beam Steering for Transmit and Receive

    NARCIS (Netherlands)

    Dijk, R. van; Houwen, E.H. van der; Maas, A.P.M.

    2008-01-01

    A phased-array FMCW radar has been design and built from COTS components. The generation of the frequency sweep is done by mixing a central local oscillator signal with a baseband sweep of a direct digital synthesizer (DDS). To ensure maximum flexibility the receive side has been equipped with it's

  2. Beam Steering of Electrically Segmented Piezo-Ceramic Ultrasonic Transducers Using Normal Mode Coupling.

    Science.gov (United States)

    2014-09-26

    Eslambolchi Committee in Charge: Professor Victor C. Anderson, Chair Professor Charles W. Vanatta , Professor Barney J. Rickett Professor Manuel Rotenberg...the sequence needed to step the motor via the parallel printer port. The data reduction was controlled in the software and then stored on a 5 1/4

  3. Micromachined low-mass RF front-end for beam steering radar

    Science.gov (United States)

    Vahidpour, M.; Moallem, M.; East, J.; Sarabandi, K.

    2012-06-01

    Sensors for autonomous small robotic platforms must be low mass, compact size and low power due to the limited space. For such applications, as the dimensions of the structures shrink, standard machining methods are not suitable because of low fabrication tolerances and high cost in assembly. Commonly, the structures show a high degree of fabrication complexity due to error in alignment, air gaps between conductive parts, poor metal contact, inaccuracy in patterning because of non-contact lithography, complex assemblies of various parts, and high number of steps needed for construction. However, micromachining offers high fabrication precision, provides easy fabrication and integration with active devices and hence is suitable for manufacturing high MMW and submillimeter-wave frequency structures. A radar design compatible with micromachining process is developed to fabricate a Y-band high resolution radar structure with a slot-fed patch array antenna. A multi-step silicon DRIE process is developed for the fabrication of the waveguide structure while the slots are suspended on a thin oxide/nitride/oxide membrane to form the top cover of the waveguide trenches and the patch elements are suspended on a thin Parylene membrane. Gold thermocompression bonding and Parylene bonding are used to assemble different parts of the antenna. These processes result in a compact (4.5 cm × 3.5 cm × 1.5 mm) and light-weight (5 g) radar.

  4. A Method for Eliminating Beam Steering Error for the Modulated Absorption-Emission Thermometry Technique

    Science.gov (United States)

    2015-01-01

    currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) December 2014 2. REPORT TYPE...Briefing Charts 3. DATES COVERED (From - To) December 2014- January 2015 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER N/A A Method for Eliminating...Jan 2015. PA#14562. 14. ABSTRACT Modulated absorption-emission thermometry (MAET) is a non-intrusive, radiometric technique for measuring line-of

  5. Beam collimator

    CERN Multimedia

    1977-01-01

    A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.

  6. All-optical delay technique for supporting multiple antennas in a hybrid optical - wireless transmission system

    DEFF Research Database (Denmark)

    Prince, Kamau; Chiuchiarelli, A; Presi, M

    2008-01-01

    We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency.......We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency....

  7. Plasmon switching: observation of dynamic surface plasmon steering by selective mode excitation in a sub-wavelength slit.

    Science.gov (United States)

    Raghunathan, S B; Gan, C H; van Dijk, T; Ea Kim, B; Schouten, H F; Ubachs, W; Lalanne, P; Visser, T D

    2012-07-02

    We report a plasmon steering method that enables us to dynamically control the direction of surface plasmons generated by a two-mode slit in a thin metal film. By varying the phase between different coherent beams that are incident on the slit, individual waveguide modes are excited. Different linear combinations of the two modes lead to different diffracted fields at the exit of the slit. As a result, the direction in which surface plasmons are launched can be controlled. Experiments confirm that it is possible to distribute an approximately constant surface plasmon intensity in any desired proportion over the two launching directions. We also find that the anti-symmetric mode generates surface plasmons more efficiently than the fundamental symmetric mode.

  8. Dynamic PL&T using Two Reference Nodes Equipped with Steered Directional Antenna for Significant PL&T Accuracy

    CERN Document Server

    Shakhakarmi, Niraj

    2012-01-01

    Dynamic Position Location and Tracking (PL&T) is proposed deploying the integrated approach of zone finding and triangulation using two friendly nodes equipped with Steered Directional Antenna (DA) in Mobile Ad hoc Networks (MANET). This approach allows the system to use only two references instead of a typical 3 references for a straight triangulation. Moreover, the performance of the proposed algorithm with references using directional antennas shows significant improvement over triangulation using references with Omnidirectional antennas as the beam power is concentrated. However, dynamic switching of reference nodes is frequently required as the target moves outside the predicted zone. This paper presents a better tracking accuracy in using proposed dynamic PL&T as compared to other PL&T techniques. The multipath fading is also addressed with the use of KV transform coding technique which uses forward error correction and sample interleaving achieves greater than 90% tracking accuracy with BER...

  9. commensurate point delays

    Directory of Open Access Journals (Sweden)

    M. de la Sen

    2005-01-01

    nominal controller is maintained. In the current approach, the finite spectrum assignment is only considered as a particular case of the designer's choice of a (delay-dependent arbitrary spectrum assignment objective.

  10. Steering far-field spin-dependent splitting of light by inhomogeneous anisotropic media

    CERN Document Server

    Ling, Xiaohui; Luo, Hailu; Wen, Shuangchun

    2012-01-01

    An inhomogeneous anisotropic medium with specific structure geometry can apply tunable spin-dependent geometrical phase to the light passing through the medium, and thus can be used to steer the spin-dependent splitting (SDS) of light. In this paper, we exemplify this inference by the $q$-plate, an inhomogeneous anisotropic medium. It is demonstrated that when a linearly polarized light beam normally passes through a $q$-plate, $k$-space SDS first occurs, and then the real-space SDS in the far-field focal plane of a converging lens is distinguishable. Interestingly, the SDS, described by the normalized Stokes parameter $S_3$, shows a multi-lobe and rotatable splitting pattern with rotational symmetry. Further, by tailoring the structure geometry of $q$-plate or/and incident polarization angle of light, the lobe number and the rotation angle both are tunable. Our result suggests that the $q$-plate can serve as potential devices for manipulating the photon spin states and enable applications such as in nano-opt...

  11. Time Delay Cosmography

    OpenAIRE

    Treu, Tommaso; Marshall, Philip J.

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector,...

  12. Diffraction control of subwavelength structured light beams in Kapitza media.

    Science.gov (United States)

    Huang, Changming; Ye, Fangwei; Chen, Xianfeng

    2015-05-18

    Kapitza tandem structures, consisting of thin alternating layers with opposite signs of the dielectric permittivity, have been recently predicted to afford diffraction arrest of focused microwave radiation [Phys. Rev. Lett. 110, 143901 (2013)]. Here we study the applicability of the Kapitza effect to control the propagation of structured subwavelength light beams. We show that a sufficiently deep modulation of the dielectric permittivity allows a nearly complete diffraction cancellation of multiple-peak subwavelength beams, and we study how the degree of diffraction cancellation decreases as the spatial spectrum of the input beam broadens. We also find that subwavelength light beams can be steered by varying the depth of the permittivity modulation. In particular, a sufficiently large permittivity modulation is shown to cause otherwise titled inputs to propagate always along the direction of modulation.

  13. Frequency-dependent optical steering from subwavelength plasmonic structures.

    Science.gov (United States)

    Djalalian-Assl, A; Gómez, D E; Roberts, A; Davis, T J

    2012-10-15

    We show theoretically and with numerical simulations that the direction of the in-plane scattering from a subwavelength optical antenna system can be controlled by the frequency of the incident light. This optical steering effect does not rely on propagation phase shifts or diffraction but arises from phase shifts in the localized surface plasmon modes of the antenna. An analytical model is developed to optimize the parameters for the configuration, showing good agreement with a rigorous numerical simulation. The simulation predicts a 25° angular shift in the direction of the light scattered from two gold nanorods for a wavelength change of 12 nm.

  14. Hierarchical Visual Analysis and Steering Framework for Astrophysical Simulations

    Institute of Scientific and Technical Information of China (English)

    肖健; 张加万; 原野; 周鑫; 纪丽; 孙济洲

    2015-01-01

    A framework for accelerating modern long-running astrophysical simulations is presented, which is based on a hierarchical architecture where computational steering in the high-resolution run is performed under the guide of knowledge obtained in the gradually refined ensemble analyses. Several visualization schemes for facilitating ensem-ble management, error analysis, parameter grouping and tuning are also integrated owing to the pluggable modular design. The proposed approach is prototyped based on the Flash code, and it can be extended by introducing user-defined visualization for specific requirements. Two real-world simulations, i.e., stellar wind and supernova remnant, are carried out to verify the proposed approach.

  15. AN ALGORITHM FOR STEERING CONTROL WITH SIMULATION RESULTS

    OpenAIRE

    Apeksha V. Sakhare,; Prof. Dr. V. M. Thakare; Prof. R. V. Dharaskar

    2010-01-01

    The idea behind the paper was channelization of human thoughts to automated realization. It is decided to implement the theme of automatic maneuvering of vehicles and the unanimous choice of sensor was touch screen. It was started with the thought of being able to replace the steering of a car completely by a touch screen. It is drawn on the experience of driving to reach at the choice of touch screen as a drive interface. Another innovation was the touch screen controller being wireless. The...

  16. Adaptive feedback linearization applied to steering of ships

    Directory of Open Access Journals (Sweden)

    Thor I. Fossen

    1993-10-01

    Full Text Available This paper describes the application of feedback linearization to automatic steering of ships. The flexibility of the design procedure allows the autopilot to be optimized for both course-keeping and course-changing manoeuvres. Direct adaptive versions of both the course-keeping and turning controller are derived. The advantages of the adaptive controllers are improved performance and reduced fuel consumption. The application of nonlinear control theory also allows the designer in a systematic manner to compensate for nonlinearities in the control design.

  17. Growth, carcass characteristics, and profitability of organic versus conventional dairy beef steers.

    Science.gov (United States)

    Bjorklund, E A; Heins, B J; Dicostanzo, A; Chester-Jones, H

    2014-03-01

    Bull calves (n=49), born at the University of Minnesota West Central Research and Outreach Center (Morris) between March and May 2011, were used to compare growth measurements and profitability of conventional and organic dairy steers. Calves were assigned to 1 of 3 replicated groups at birth: conventional (CONV; n=16), organic (pasture and concentrate; ORG; n=16), or organic grass only (GRS; n=17), and analysis of variables was on a pen basis. Breed groups of calves were Holstein (HO; n=9); Holsteins (n=11) maintained at 1964 breed average level; crossbreds (n=19) including combinations of HO, Montbéliarde, and Swedish Red; and crossbreds (n=10) including combinations of HO, Jersey, Swedish Red, and Normande. The CONV steers were fed a diet of 80% concentrate and 20% forage. The ORG steers were fed a diet of organic corn, organic corn silage, and at least 30% of their diet consisted of organic pasture during the grazing season. The GRS steers grazed pasture during the grazing season and were fed high-quality hay or hay silage during the nongrazing season. Intakes of a total mixed ration were recorded daily with herd management software. A profit function was defined to include revenues and expenses for beef value, feed intake, pasture intake, health cost, and yardage. The GRS (358.6 kg) steers had lesser total gains from birth to slaughter than ORG (429.6 kg) and CONV (534.5 kg) steers. Furthermore, the GRS (0.61 kg/d) steers had lesser average daily gain from birth compared with ORG (0.81 kg/d) and CONV (1.1 kg/d) steers. The GRS and ORG steers had smaller rib eye area (49.5 and 65.8 cm(2), respectively) compared with CONV (75.4 cm(2)) steers. For profitability, GRS steers had 43% greater profit than CONV steers due to organic beef price premiums and lower feed costs. On the other hand, ORG steers had substantially less profit than CONV steers. The higher cost of production for the ORG steers is due to the extreme high value of organic corn. The results of the

  18. Evaluation of Potential Usage of Incremental-Type Rotary Encoder Application for Angle Sensing in Steering System

    Directory of Open Access Journals (Sweden)

    Sunarto Kaleg

    2014-12-01

    Full Text Available The main target of a steering system is that the driver can change vehicle trajectory in accordance with the desired direction.  Power steering has become a standard feature in automobile.  It provides assisting power when the driver turns the steering wheel. The well-known power steering types include; Hydraulic Power Steering (HPS, Electro - Hydraulic Power Steering (EHPS, and Electric Power Steering (EPS. EHPS or EPS uses an Electronic Control Unit (ECU which is specific for each vehicle. The ECU should be able to regulate power of electric motor to provide corresponding assisting power for the steering wheel. Therefore ECU requires input signals, one of which is vehicle wheel angle that can be indicated from the vehicle steering wheel angle. Incremental type of Rotary Encoder (RE is used in steering angle sensor on a minibus. RE specification used was 60 pulses per rotation and the minibus steering transmission specification is 3.5 round of right wheel off angle to the left wheel off angle. So we get the RE angular resolution 6ºper pulse and 105 number of pulses to half of the steering transmission ratio. Repeatability then tested against to a steering angle counter module. Testing is done with a test cycle consisting of 3 repetitions: condition center of the steering wheel, the steering wheel is turned to full right, then to the full left, then back to the right up to the steering wheel center. The results obtained 2 pulses deviation, or equivalent to 12º of steering angle.

  19. Steerable pencil beams for multi-Gbps indoor optical wireless communication.

    Science.gov (United States)

    Oh, C W; Tangdiongga, E; Koonen, A M J

    2014-09-15

    We report a novel optical wireless communication (OWC) system solution that supports multi-Gbps (Gigabit-per-second) capacity for indoors. Narrow beams, termed as pencil beams, are directed to wireless users using a tunable laser and a passive diffractive optical element. This enables a wide coverage of ultra-high-capacity communication links to serve multiple network users simultaneously. Experimental results demonstrating data rates of up to 10 Gbps, with on-off keying modulation format, over a distance of more than 2.5 m, are reported. Error-free links beam-steered over a total wavelength range of 130 nm, with steering angle of 17.16°, have been achieved. This system is proposed for short-range OWC and is promising for seamless integration in in-building optical networks.

  20. A parametric study of ultrasonic beam profiles for a linear phased array transducer.

    Science.gov (United States)

    Lee, J H; Choi, S W

    2000-01-01

    A numerical simulation model is presented to investigate the influences of design parameters of linear phased array transducers on beam focusing and steering performance. The characteristic of ultrasonic beam profiles has been simulated on the basis of the Huygen's superposition principle. For the simulation, a linear phased array is considered as the composition of finite number of elements separated by equidistance. Individual elements are considered as two-dimensional point sources. The waves generated from piezoelectric elements are considered as simplified transient ultrasonic waves that are constructed with the cosine function enveloped with a Hanning window. The characteristic of ultrasonic wave propagation into a medium from the phased array transducer is described. The effects of the number, the interelement spacing, steering angle, the focal length, and frequency bandwidth of the piezoelectric elements on beam directivity and ultrasonic pressure field in a linear phased array transducer are systematically discussed.

  1. Feeding behavior of steers fed a complete mixed ration.

    Science.gov (United States)

    Chase, L E; Wangsness, P J; Baumgardt, B R

    1976-11-01

    Feeding behavior of five Holstein steers fed a complete mixed ration was studied by use of individual, electronically controlled feeding behavior units. Both individual meal and daily behavioral parameters were measured. Number of meals, size of each individual meal, time spent eating, and intervals between meals were measured. Eating rates were then calculated. Diurnal feeding patterns were observed with 60.9% of the meals occurring between 0600 and 1800 h. For individual meals, body weight accounted for less than 30% of the variation in meal size. Average meal size was 414.5 g. Respective means for overall meal duration, actual meal duration, overall eating rate, and actual eating rate were 20.3 min, 13.7 min, 23.1 g/min, and 30.0 g/min. Meal size per body weight (g/kg or g/kg.75) was relatively constant during observation. Both increased eating rate and increased meal length were associated with larger meals. However, eating rate tended to plateau while meal length continued to increase with larger meals. Steers consumed 10.01 meals per day while total daily overall meal duration and actual meal duration were 220.9 and 156.4 min.

  2. Stability Simulation of a Vehicle with Wheel Active Steering

    Directory of Open Access Journals (Sweden)

    Brabec Pavel

    2016-01-01

    Full Text Available This paper deals with the possibility of increasing the vehicle driving stability at a higher speed. One of the ways how to achieve higher stability is using the 4WS system. Mathematical description of vehicle general movement is a very complex task. For simulation, models which are aptly simplified are used. For the first approach, so-called single-truck vehicle model (often linear is usually used. For the simulation, we have chosen to extend the model into a two-truck one, which includes the possibility to input more vehicle parameters. Considering the 4WS system, it is possible to use a number of potential regulations. In our simulation model, the regulation system with compound coupling was used. This type of regulation turns the rear wheels depending on the input parameters of the system (steering angle of the front wheels and depending on the output moving quantities of the vehicle, most frequently the yaw rate. Criterion for compensation of lateral deflection centre of gravity angle is its zero value, or more precisely the zero value of its first-order derivative. Parameters and set-up of the simulation model were done in conjunction with the dSAPACE software. Reference performances of the vehicle simulation model were made through the defined manoeuvres. But the simulation results indicate that the rear-wheels steering can have a positive effect on the vehicle movement stability, especially when changing the driving direction at high speed.

  3. Needle Steering in 3-D Via Rapid Replanning.

    Science.gov (United States)

    Patil, Sachin; Burgner, Jessica; Webster, Robert J; Alterovitz, Ron

    2014-08-01

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm.

  4. Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

    Directory of Open Access Journals (Sweden)

    Roberta Carrilho Canesin

    2014-04-01

    Full Text Available Reduced supplementation frequency is a broadly applied management practice. Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG, efficiency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI, dry matter and organic matter digestibility (DMD and OMD, BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg were distributed over nine paddocks according to a completely randomized design. Treatments were based on supplementation frequency: once daily (OD, once daily except Saturdays and Sundays (SS, or on alternate days (AD, at 1.0 %, 1.4 % and 2.0 % BW, respectively. Average total DMI accounted for 1.6 % BW day-1, with no effect of supplementation frequency. Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a finishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed efficiency or carcass quality in beef cattle grazing tropical pastures.

  5. Research on the Steering Strategy for Hydrogen Maser

    Science.gov (United States)

    Yin, D. S.; Zhao, S. H.; Gao, Y. P.

    2016-07-01

    In the master clock system, the local standard time UTC(k) with a better short-term stability will be generated, if the hydrogen maser is set as a frequency source of the master clock. But the hydrogen maser always exhibits an apparent frequency drift, thus its long-term stability gets poor with time, therefore the stability and accuracy of UTC(k) become worse. To solve this problem, we compare the performance of hydrogen maser with cesium clocks, and modify the time scale algorithm when the hydrogen maser is involved, we also propose a new steering strategy when hydrogen maser is used as the frequency source of master clock. We set up an experiment system and write programs, and finally the new steering strategy is testified with the laboratory data. Results show that when the hydrogen maser is involved in the atomic time scale calculation, the short-term frequency stability of reference time scale will be improved. Meanwhile, the local time UTC(k) has a better short-term frequency stability when the frequency source of the master clock uses hydrogen maser instead of cesium clock.

  6. Needle Steering in 3-D Via Rapid Replanning

    Science.gov (United States)

    Patil, Sachin; Burgner, Jessica; Webster, Robert J.; Alterovitz, Ron

    2014-01-01

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm. PMID:25435829

  7. Aeronautical satellite antenna steering using magnetic field sensors

    Science.gov (United States)

    Sydor, John; Dufour, Martial

    1993-01-01

    Designers of aeronautical satellite terminals are often faced with the problem of steering a directive antenna from an airplane or helicopter. This problem is usually solved by using aircraft orientation information derived from inertial sensors on-board the aircraft in combination with satellite ephemeris information calculated from geographic coordinates. This procedure works well but relies heavily on avionics that are external to the terminal. For the majority of small aircraft and helicopters which will form the bulk of future aeronautical satcom users, such avionics either do not exist or are difficult for the satellite terminal to interface with. At the Communications Research Center (CRC), work has been undertaken to develop techniques that use the geomagnetic field and satellite antenna pointing vectors (both of which are stationary in a local geographical area) to track the position of a satellite relative to a moving platform such as an aircraft. The performance of this technique is examined and a mathematical steering transformation is developed within this paper. Details are given regarding the experimental program that will be undertaken to test the concepts proposed herein.

  8. Motion Synthesis of a Self-Steered Mobile Robot

    Science.gov (United States)

    Roseborrough, Michael; Phillips, Keith

    1987-02-01

    Until the late 1950's there was an almost exclusive use of graphical methods in the kinematic analysis and synthesis of mechanisms. With the increasing availability of high-speed digital computers there was a major reawakening of interest in a field con-sidered by many to be mature and dormant. Today the birth of advanced robotic systems has heightened the interest in applications of kinematic analysis and synthesis. This paper discusses the application of kinematics to the path planning model of a three wheeled, self-steering, mobile robot. The problem is formulated through a kinematic analysis of the path curvature and the synthesis of a set of equivalent linkages. The equivalent linkages facilitate a direct relationship between the path and the robot steering control mechanism. This is accomplished through the kinematic param-eters displacement, velocity and acceleration. The mathematical model is presented in a generalized format with the robot represented as a rigid body. Examples are shown which solve the problem of moving the robot through a crowded environment and arriving at its destination in a predetermined orientation.

  9. Monitoring and Steering of Large-Scale Distributed Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Geist, G.A.; Kohl, J.A.

    1999-09-01

    Oak Ridge National Laboratory is developing a state-of-the-art parallel application development system called CUMULVS, which allows scientists to easily incorporate interactive visualization, computational steering and fault tolerance into distributed software applications. The system is a valuable tool for many large scientific applications because it enables the scientist to visually monitor large data fields and remotely control parameters inside a running application. Collaborative monitoring is provided by allowing multiple researchers to simultaneously attach to a simulation, each controlling their own view of the same or different data fields within the simulation. By supporting steering of a simulation while it is running, CUMULVS provides the opportunity to accelerate the process of scientific discovery. CUMULVS also provides a simple mechanism to incorporate automatic checkpointing and heterogeneous task migration into large applications so that simulations can continue to run for weeks unattended. This paper will give an overview of the CUMULVS system and its capabilities, including several case histories. The status of the project is described with instructions on how to obtain the software.

  10. Defining Value in Cancer Care: AVBCC 2013 Steering Committee Report.

    Science.gov (United States)

    Zweigenhaft, Burt; Bosserman, Linda; Kenney, James T; Lawless, Grant D; Marsland, Thomas A; Deligdish, Craig K; Burgoyne, Douglas S; Knopf, Kevin B; Long, Douglas M; McKercher, Patrick; Owens, Gary M; Hennessy, John E; Lang, James R; Malin, Jennifer; Natelson, Leonard; Palmgren, Matthew C; Slotnik, Jayson; Shockney, Lillie D; Vogenberg, F Randy

    2013-07-01

    The AVBCC Annual Meeting experiences exponential growth in attendance and participation as oncologists, payers, employers, managed care executives, patient advocates, and drug manufacturers convened in Hollywood, FL, on May 2-5, 2013, for the Third Annual Conference of the Association for Value-Based Cancer Care (AVBCC). The conference presented an all-inclusive open forum for stakeholder dialogue and integration across the cancer care continuum, facilitating an open dialogue among the various healthcare stakeholders to align their perspectives around the urgent need to address value in cancer care, costs, patient education, safety, outcomes, and quality. The AVBCC 2013 Steering Committee was held on the first day of the conference to define value in cancer care. The committee was divided into 7 groups, each representing a key stakeholder in oncology. The goal of the Steering Committee was to define value from the particular point of view of each of the stakeholder groups and to suggest how that particular perspective can contribute to the value proposition in oncology, by balancing cost, quality, and access to care to improve overall patient outcomes. The following summary highlights the major points addressed by each group.

  11. Biogas production from steer manures in Vietnam: Effects of feed supplements and tannin contents.

    Science.gov (United States)

    Pham, Cuong H; Saggar, Surinder; Vu, Cuong C; Tate, Kevin R; Tran, Thao T T; Luu, Thi T; Ha, Hanh T; Nguyen, Huong L T; Sommer, Sven G

    2017-08-05

    In developing countries, the simple biogas digesters installed underground without heating or stirring are seen as a 'green' technology to convert animal waste into biogas, a source of bio-energy. However, quantitative estimates of biogas production of manures from steers fed local feed diets at actual incubation temperatures have yet to be carried out. The aim of this study was to determine the methane (CH4) production potential of manures from steers in Vietnam offered traditional feed rations or supplemental diets. Biochemical CH4 production (BMP) was measured in batch tests at 30°C using manures collected from two different experiments of steers fed diets containing feed supplements. BMP was 110.1 (NLkg(-1)VS) for manure from steers receiving a control diet, significantly lower 79.0 (NL kg(-1)VS) for manure from steers fed a diet containing 0.3% tannin (%DM), but then showed an increasing trend to 90.9 and 91.2 (NL kg(-1)VS) for manures from steers receiving 0.4 and 0.5% tannin (%DM) supplements, respectively. Similarly, the CH4 production (NL kg(-1)VS) of manure from steers was 174 for control, 142 for control supplemented concentrate (C), 143 for control added rice straw treated with urea (R), and 127 for control supplemented C and R. Our results show there was a decrease in CH4 emissions from steer manures through using supplemented rations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Genetic effects on carcass quantity, quality, and palatability traits in straightbred and crossbred Romosinuano steers

    Science.gov (United States)

    The objectives of this work were to estimate heterosis and breed genetic effects for carcass quantity, quality, and palatability traits of steers (Bos spp.) produced from matings of Romosinuano, Brahman, and Angus cattle. Steers (n = 464) were weaned at 7 mo of age and transported to the Southern G...

  13. Application of washed rumen technique for rapid determination of fasting heat production in steers

    Science.gov (United States)

    Two experiments were conducted to evaluate the use of a washed rumen technique as an alternative approach for determining fasting HP in cattle. In Exp. 1, 8 Holstein steers (322±30 kg) were adapted to a cubed alfalfa-based diet (1.5xNEm) for 10 d. After which steers were placed into individual hea...

  14. Design and Development of Labview Based Steering Wheel Angle Sensor System

    Directory of Open Access Journals (Sweden)

    Tony George

    2015-04-01

    Full Text Available Conventional angle sensors can measure only 360°,but passenger car steering wheel turns through +/-720o (a total of 4 complete turns. In this paper we describe iGMR based steering wheel angle sensor implementation which can be used as a rotation sensor to measure +/- 720°.

  15. Does pedalling on a recumbent bicycle influence the cyclist’s steering behaviour?

    NARCIS (Netherlands)

    Boon, K.M.; Klap, P.; Van Lanen, J.A.; Letsoin, G.J.; Jansen, A.J.

    2014-01-01

    The paper presents the answer to the question how pedalling on a specific recumbent bicycle, such as the VeloX3, influences a cyclist’s ability to steer the bicycle. The research aims to find the correlation between pedalling and the undesired steering movements it creates. To test this assumption a

  16. Alteration in gene expression in the jejunum mucosa of Angus steers with divergent ADG

    Science.gov (United States)

    The objective of this study was to determine the association of differentially expressed genes in the jejunum of steers with average DMI and high or low ADG. Feed intake and growth were measured in a cohort of 144 commercial Angus steers consuming a finishing ration containing (on a DM basis) 67.8% ...

  17. Reducing Digging Losses by Using Automated Steering to Plant and Invert Peanuts

    Directory of Open Access Journals (Sweden)

    George Vellidis

    2014-07-01

    Full Text Available GPS guidance of farm machinery has been increasingly adopted by farmers because of the perceived gains in efficiency that it provides. In the southeastern USA one of the reasons farmers adopt GPS guidance, and specifically automated steering (auto-steer, is that it can theoretically result in large yield gains when used to plant and invert peanuts—one of the region’s most important crops. The goal of our study was to quantify the yield benefit of using real time kinematic (RTK-based auto-steer to plant and invert peanuts under a variety of terrain conditions. Yield benefits result from reduced digging losses. The study was conducted for two consecutive years (2010 and 2011 on a private farm in Georgia, USA. When all data are grouped together, auto-steer outperformed conventional by 579 kg/ha in 2010 and 451 kg/ha in 2011. We also evaluated the performance of auto-steer under different curvature conditions using low, medium, and high curvature rows. The results showed that auto-steer outperformed conventional under all curvature by a minimum of 338 kg/ha. Finally, we evaluated passive implement guidance in combination with auto-steer and found that it holds tremendous potential for further reducing digging losses. In many cases, auto-steer will pay for itself within a year.

  18. Integrating deflection models and image feedback for real-time flexible needle steering

    NARCIS (Netherlands)

    Abayazid, Momen; Roesthuis, Roy; Reilink, Rob; Misra, Sarthak

    2013-01-01

    Needle insertion procedures are commonly used for diagnostic and therapeutic purposes. In this paper, an image- guided control system is developed to robotically steer flexible nee- dles with an asymmetric tip. Knowledge about needle deflection is required for accurate steering. Two different models

  19. Integrating deflection models and image feedback for real-time flexible needle steering

    NARCIS (Netherlands)

    Abayazid, Momen; Roesthuis, Roy J.; Reilink, Rob; Misra, Sarthak

    2012-01-01

    Needle insertion procedures are commonly used for diagnostic and therapeutic purposes. In this paper, an image- guided control system is developed to robotically steer flexible nee- dles with an asymmetric tip. Knowledge about needle deflection is required for accurate steering. Two different models

  20. Dynamic Modeling of Hydraulic Power Steering System with Variable Ratio Rack and Pinion Gear

    Science.gov (United States)

    Zhang, Nong; Wang, Miao

    A comprehensive mathematical model of a typical hydraulic power steering system equipped with variable ratio rack and pinion gear is developed. The steering system’s dynamic characteristics are investigated and its forced vibrations are compared with those obtained from a counterpart system with a constant ratio rack and pinion gear. The modeling details of the mechanism subsystem, hydraulic supply lines subsystem and the rotary spool valve subsystem are provided and included in the integrated steering system model. The numerical simulations are conducted to investigate the dynamics of the nonlinear parametric steering system. From the comparison between simulated results and the experimental ones, it is shown that the model accurately integrates the boost characteristics of the rotary spool valve which is the key component of hydraulic power steering system. The variable ratio rack-pinion gear behaviors significantly differently from its constant ratio counterpart does. It significantly affects not only the system natural frequencies but also reduces vibrations under constant rate and ramp torque steering inputs. The developed steering model produces valid predictions of the system’s behavior and therfore could assist engineers in the design and analysis of integrated steering systems.

  1. Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae

    Science.gov (United States)

    This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 266 ± 4 kilograms body weight) were separated into three treatment groups (n = 6/treatm...

  2. Relationship of leptin concentrations with feed intake, growth, and efficiency in finishing beef steers

    Science.gov (United States)

    The objective of this experiment was to determine the association of serum leptin concentrations with production measures including DMI, ADG, G:F as well as carcass characteristics in genetically diverse finishing beef steers. Three cohorts of steers (n = 473 total) were individually fed a finishin...

  3. Differential acute phase immune responses by Angus and Romosinuano steers following an endotoxin challenge

    Science.gov (United States)

    Our primary objective was to evaluate potential genetic differences between two diverse Bos taurus breeds (Angus (AG) and Romosinuano (RO)) in response to an endotoxin. The RO is a tropically adaptive Bos taurus breed developed in the Sinú valley of northern Colombia. Eighteen steers (n = 9 steers/b...

  4. Exogenous administration of lipids to steers alters aspects of the innate immune response to endotoxin challenge

    Science.gov (United States)

    Limitations in energy availability are known to impede the efficiency of the immune response to endotoxemia. Therefore, this study examined the effects of increasing energy availability on the pro-inflammatory response to LPS in Holstein steers. Steers were randomly assigned to 1 of 3 groups (n = 7 ...

  5. Effects of clay on fat necrosis and carcass characteristics in Japanese Black steers

    National Research Council Canada - National Science Library

    Oka, Akio; Iwamoto, Eiji; Tatsuda, Ken

    2015-01-01

    Twenty 10‐month‐old J apanese B lack steers were used to evaluate the effects of clay on fat necrosis and carcass characteristics. Ten steers ( C lay group) were fed the clay (50 g/day) during 10–30 months of age...

  6. Effects of steering demand on lane keeping behaviour, self-reports, and physiology : A simulator study

    NARCIS (Netherlands)

    Dijksterhuis, Chris; Brookhuis, Karel A.; De Waard, Dick

    2011-01-01

    In this study a driving simulator was used to determine changes in mental effort in response to manipulations of steering demand. Changes in mental effort were assessed by using subjective effort ratings, physiology, and the standard deviation of the lateral position. Steering demand was increased b

  7. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Science.gov (United States)

    2010-10-01

    ... must be installed in the pilothouse to indicate operation of the power units. (e) The auxiliary means... 46 Shipping 4 2010-10-01 2010-10-01 false Steering on OSVs of less than 100 gross tons. 130.130... VESSEL CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Vessel Control § 130.130 Steering on OSVs of...

  8. Optimized detection of steering via linear criteria for arbitrary-dimensional states

    Science.gov (United States)

    Zheng, Yu-Lin; Zhen, Yi-Zheng; Cao, Wen-Fei; Li, Li; Chen, Zeng-Bing; Liu, Nai-Le; Chen, Kai

    2017-03-01

    Einstein-Podolsky-Rosen (EPR) steering, as a new form of nonlocality, stands between entanglement and Bell nonlocality, implying promising applications for quantum information tasks. The problem of detecting EPR steering plays an important role in characterization of quantum nonlocality. Despite some significant progress, one still faces a practical issue: how to detect EPR steering in an experimentally friendly fashion. Resorting to an EPR steering inequality, one is required to apply a strategy as efficiently as possible for any selected measurement settings on the two subsystems, one of which may not be trusted. Inspired by the recent powerful linear criteria proposed by Saunders et al. [D. J. Saunders, S. J. Jones, H. M. Wiseman, and G. J. Pryde, Nat. Phys. 6, 845 (2010)., 10.1038/nphys1766], we present an optimized method of certifying steering for an arbitrary-dimensional state in a cost-effective manner. We provide a practical way to signify steering via only a few settings to optimally violate the steering inequality. Our method leads to steering detections in a highly efficient way, and can be performed with any number of settings, for an arbitrary bipartite mixed state, which can reduce experimental overheads significantly.

  9. Carcass characteristics and composition of Brahman, angus and Brahman x Angus steers fed for different times-on-feed.

    Science.gov (United States)

    Lunt, D K; Smith, G C; Murphey, C E; Savell, J W; Carpenter, Z L; Petersen, H D

    1985-01-01

    Twenty-five steers of each of three breedtypes (Angus, Brahman and F(1) Brahman x Angus) were sorted by frame size and muscle thickness, assigned to groups (five steers of each breedtype) to be fed for 0, 56, 112, 168 or 224 days, slaughtered and compared for various carcass traits. Steers of each breedtype had similar dressing percentages. Carcasses from all three breedtypes merited similar USDA quality and yield grades; breedtypes differences in quality grade were slight. Differences were found in the fat deposition patterns exhibited by the three breedtypes. Brahman steers tended to deposit more of their total fat as subcutaneous fat early in the feeding period. Angus steers had more (P carcass weight at all five feeding periods and more (P Brahman steers. Brahman steers had a higher percentage of their separable lean in the muscles of the round than did steers of the other breedtypes.

  10. Compact Dielectric-Rod White-Light Delay Lines

    Science.gov (United States)

    Maleki, Lute; Matsko, Andrey; Savchenkov, Anatoliy; Strekalov, Dmitry

    2008-01-01

    Optical delay lines of a proposed type would be made from rods of such dielectric materials as calcium fluoride, fused silica, or sapphire. These would offer advantages over prior optical delay lines, as summarized below. Optical delay lines are key components of opto-electronic microwave oscillators, narrow-band opto-electronic microwave filters, evanescent-field optical biochemical detectors, and some Fourier-Transform spectrum analyzers. Heretofore, optical delay lines used in such applications have been of two types: resonators and coiled long optical fibers, both of which have disadvantages: Resonators are compact, but excitation must be provided by narrow-band lasers. Wide-band (including noisy) laser light cannot be coupled efficiently to narrow-band resonators. When light is coupled into a narrowband resonator from a source of reasonably high power, a significant amount of optical energy circulates within the resonator, causing nonlinear loss and significant noise. Typically, a coil-type optical delay line is made of fused-silica fiber, which exhibits fundamental loss. To overcome the limit imposed by the optical loss in fused silica, it would be necessary to use fibers having crystalline cores. Although space is saved by winding fibers into coils, fiber-coil delay lines are still inconveniently bulky. The proposed compact dielectric-rod delay lines would exploit the special class of non-diffracting light beams that are denoted Bessel beams because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have large values of angular momentum. They can be generated with the help of whispering-gallery-mode optical resonators, as described, for example, in "Simplified Generation of High-Angular-Momentum Light Beams" (NPO-42965) NASA Tech Briefs, Vol. 31, No. 3 (March 2007), page 8a. In a delay line according to the proposal, the dielectric rod would be dimensioned to function as a multimode

  11. A study of a steering system algorithm for pleasure boats based on stability analysis of a human-machine system model

    Science.gov (United States)

    Ikeda, Fujio; Toyama, Shigehiro; Ishiduki, Souta; Seta, Hiroaki

    2016-09-01

    Maritime accidents of small ships continue to increase in number. One of the major factors is poor manoeuvrability of the Manual Hydraulic Steering Mechanism (MHSM) in common use. The manoeuvrability can be improved by using the Electronic Control Steering Mechanism (ECSM). This paper conducts stability analyses of a pleasure boat controlled by human models in view of path following on a target course, in order to establish design guidelines for the ECSM. First, to analyse the stability region, the research derives the linear approximated model in a planar global coordinate system. Then, several human models are assumed to develop closed-loop human-machine controlled systems. These human models include basic proportional, derivative, integral and time-delay actions. The stability analysis simulations for those human-machine systems are carried out. The results show that the stability region tends to spread as a ship's velocity increases in the case of the basic proportional human model. The derivative action and time-delay action of human models are effective in spreading the stability region in their respective ranges of frontal gazing points.

  12. Comparative stress responses to short transport and related events in Hereford and Brahman steers.

    Science.gov (United States)

    Browning, R; Leite-Browning, M L

    2013-02-01

    Three summer experiments compared responses to transportation-related events in 2- to 4-yr-old Brahman (Bos indicus) and Hereford (B. taurus) steers. In Exp. 1, steers were hauled round-trip (4 h) or fasted in holding pens. Transport transiently increased (P Brahman across treatments. Steers in Exp. 2 were hauled to a new farm for a 1-wk relocation period or hauled round-trip an equal time (0.67 h) and returned to the home station. Both treatments similarly experienced transport-day BW shrink and increased (P Brahman. Relocation did not elicit (P Brahman steers were not more sensitive than Herefords. Hereford steers were susceptible to greater transport BW shrink than Brahman under the summer conditions.

  13. The Design of a Controller for the Steer-by-Wire System

    Science.gov (United States)

    Oh, Se-Wook; Chae, Ho-Chol; Yun, Seok-Chan; Han, Chang-Soo

    Drive-by-Wire (DBW) technologies improve conventional vehicle performance and a Steer-by-Wire (SBW) system is one of the DBW technologies. The control algorithm of the SBW system was designed in this paper. To verify the control algorithm, the SBW system is modeled using the bond graph method. The first aim of the control algorithm is controlling the steering wheel assist motor to make the real vehicle's steering feel and for a vehicle designer to adjust the steering feel as he finds necessary. Therefore, torque map is designed to determine the steering wheel reactive torque. The second aim is controlling the front wheel assist motor to improve vehicle's maneuverability and stability by using understeer and oversteer propensity of a vehicle. Furthermore, high performance control algorithm is proposed in this paper and Active Roll Stability Control (ARSC) method is designed as one of the high performance control algorithm.

  14. Robust PID Steering Control in Parameter Space for Highly Automated Driving

    Directory of Open Access Journals (Sweden)

    Mümin Tolga Emirler

    2014-01-01

    Full Text Available This paper is on the design of a parameter space based robust PID steering controller. This controller is used for automated steering in automated path following of a midsized sedan. Linear and nonlinear models of this midsized sedan are presented in the paper. Experimental results are used to validate the longitudinal and lateral dynamic models of this vehicle. This paper is on automated steering control and concentrates on the lateral direction of motion. The linear model is used to design a PID steering controller in parameter space that satisfies D-stability. The PID steering controller that is designed is used in a simulation study to illustrate the effectiveness of the proposed method. Simulation results for a circular trajectory and for a curved trajectory are presented and discussed in detail. This study is part of a larger research effort aimed at implementing highly automated driving in a midsized sedan.

  15. Analysis of Steering Knuckle of All Terrain Vehicles (ATV) Using Finite Element Analysis

    Science.gov (United States)

    Dusane, S. V.; Dipke, M. K.; Kumbhalkar, M. A.

    2016-09-01

    Steering knuckle is the most stress sustaining and critical component of All Terrain Vehicle (ATV). Steering knuckle is the pivot point of the steering and suspension system, which allows the front wheels to turn and also allow the movement of suspension arms motion. The light weight and high strength component is always in demanding for racecar application. Lightweight and optimized design of steering knuckle is proposed to use for a BAJA SAE INDIA off road racecar. Due to the failure in knuckle in terrain vehicle after some instances, it has to be modified for better performance. The 3D CAD model created by using CATIA V5 and static as well as model analysis carried out in ANSYS 12 to understand its behavior under operating conditions. All test for frame was carried out on aluminum alloys 6061-T6 & for spindle EN8. The paper discusses the FE analysis of existing and modified Steering Knuckle.

  16. One-way steering of optical fields via dissipation of an atomic reservoir

    Science.gov (United States)

    Rao, Shi; Hu, Xiangming; Li, Lingchao; Xu, Jun

    2016-11-01

    Einstein-Podolsky-Rosen (EPR) steering as a form of quantum correlation lies between entanglement and Bell nonlocality and exhibits an inherent asymmetry between two observers. We study EPR steering of two fields, which are generated via four-wave mixing processes and are entangled with each other due to the dissipation of the atomic reservoir. It is shown that the one-way steering happens from one mode to the other for different cavity decay rates and not too small cooperation parameters. Depending on the adiabatic and nonadiabatic conditions, the one-way steering occurs in a different detuning region when the cooperation parameters are relatively small. An increase in the cooperation parameters leads to an increase both in the parameter region and in the degree for the one-way steering. Finally we generalize the present scheme to the cases of the bright and/or collective fields.

  17. Effect of abomasal infusion of aspartate on nitrogen balance and plasma amino acids in Holstein steers.

    Science.gov (United States)

    Wessels, R H; Titgemeyer, E C

    1998-01-01

    We investigated the effect of abomasally infused aspartate (Asp) on N balance and plasma amino acids in steers. Four ruminally cannulated Holstein steers (180 kg) housed in metabolism crates were used in an experiment designed as a 4 x 3 Youden square. Steers received continuous abomasal infusions of water or water containing 40 or 80 g Asp/d. Steers were fed twice daily a diet containing 473 g/kg corn, 463 g/kg alfalfa hay and 52 g/kg soybean meal at levels near ad libitum intake. Abomasally infused Asp had no effect on N balance. Infusion of 80 g Asp/d increased (P < 0.05) plasma concentrations of Asp, glutamate and alanine. Metabolism of Asp by gut tissues probably prevented the large change in plasma concentration of Asp that seems necessary to trigger hormonal responses. We conclude that abomasal supplementation of steers with up to 80 g/d of Asp does not enhance performance.

  18. Time Delay Cosmography

    CERN Document Server

    Treu, Tommaso

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  19. Prediction of delayed subsidence

    Science.gov (United States)

    Burns, K.

    A predictive model of delayed subsidence is discussed. A numerical implementation is tested on one of the best-described study areas, Allegheny County in Pennsylvania. In planning insurance of restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods were introduced to deal with the problem, ranging from subsidence insurance to site restitution.

  20. Time delay cosmography

    Science.gov (United States)

    Treu, Tommaso; Marshall, Philip J.

    2016-07-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  1. Postgraze assessment of toxicosis symptoms for steers grazed on toxic endophyte-infected tall fescue pasture.

    Science.gov (United States)

    Aiken, G E; Klotz, J L; Johnson, J M; Strickland, J R; Schrick, F N

    2013-12-01

    A 2-yr pen experiment was conducted using 12 different crossbred Angus steers each year to determine if short-term changes in prolactin concentrations, body temperature, and vasoconstriction reflect recovery from fescue toxicosis after steers that previously grazed toxic endophyte (Neotyphodium coenophialum)-infected Kentucky 31 tall fescue [Lolium arundinaceum (Schreb.) Darbysh] are placed on nontoxic feed. Groups of 6 steers from toxic endophyte-infected and endophyte-free tall fescue grazing treatments were blocked by BW for assignment to pens as a randomized complete block design with 2 replications. Two environments were implemented by initiating the experiment on 18 August in yr 1 and on 8 September in yr 2 for durations of 30 and 21 d, respectively. Rectal temperatures were recorded, jugular blood was collected for assaying serum prolactin, and cross sections of the caudal artery were ultrasonically imaged at selected time points to evaluate temporal changes in the response variables. Rectal temperatures in steers on the toxic endophyte pasture treatment declined (P 0.10) to those on endophyte-free treatment on d 30 in yr 1 and by d 15 in yr 2. Prolactin concentrations in steers on the toxic endophyte pasture treatment showed curvilinear increases (P 0.10) to steers on the endophyte-free treatment by d 15 in yr 1 and by d 10 in yr 2. Luminal areas of the caudal artery in toxic endophyte steers were less (P endophyte-free steers across all dates in both years. Results indicated that rectal temperatures in steers after they are removed from toxic fescue may decrease over time, but temporal changes in rectal temperatures could be affected more by prevailing ambient temperatures than by actual mitigation of fescue toxicosis. Prolactin concentrations in steers after they are removed from toxic endophyte tall fescue can increase and stabilize in less than 2 wk, but alkaloid-induced vasoconstriction that causes a vulnerability to severe heat stress is not

  2. Delayed Random Relays

    CERN Document Server

    Ohira, Toru

    2016-01-01

    We present here a system with collection of random walks relaying a signal in one dimension with a presence of a delay. We are interested in the time for a signal to travel from one end (start) to the other end (finish) of the lined group of random walkers. It is found that there is an optimal number of walkers for the signal to travel fastest if the delay is present. We discuss implications of this model and associated behaviors to physical and biological systems.

  3. Approximation of distributed delays

    CERN Document Server

    Lu, Hao; Eberard, Damien; Simon, Jean-Pierre

    2010-01-01

    We address in this paper the approximation problem of distributed delays. Such elements are convolution operators with kernel having bounded support, and appear in the control of time-delay systems. From the rich literature on this topic, we propose a general methodology to achieve such an approximation. For this, we enclose the approximation problem in the graph topology, and work with the norm defined over the convolution Banach algebra. The class of rational approximates is described, and a constructive approximation is proposed. Analysis in time and frequency domains is provided. This methodology is illustrated on the stabilization control problem, for which simulations results show the effectiveness of the proposed methodology.

  4. A Hardware Transverse Beam Frequency Response Simulator

    CERN Document Server

    Ning, Jia

    2005-01-01

    We build an electronical instrument to get the frequency response close to the pattern of transverse beam frequency response. The method is to apply 1)a time delay circuit with ADC, FIFO RAM and DAC; 2)a phase shift circuit which is an all pass filter with adjustable phase shift in the frequency range of 25kHz to 30kHz; in a feedback loop of 3)a commutating filter which is a high Q band pass filter. We can dynamically adjust the center frequency, the side band distance during the testing. With this instrument, some beam instruments can be tested without using the real beam.

  5. Optimal Source Tracking and Beaming of LISA

    CERN Document Server

    Pai, A

    2007-01-01

    We revisit the directionally optimal data streams of LISA first introduced in Nayak etal. It was shown that by using appropriate choice of Time delay interferometric (TDI) combinations, a monochromatic fixed source in the barycentric frame can be optimally tracked in the LISA frame. In this work, we study the beaming properties of these optimal streams. We show that all the three streams V+, Vx and Vo with maximum, minimum and zero directional SNR respectively are highly beamed. We study in detail the frequency dependence of the beaming.

  6. Development of beam current control system in RF-knockout slow extraction

    Science.gov (United States)

    Mizushima, K.; Sato, S.; Shirai, T.; Furukawa, T.; Katagiri, K.; Takeshita, E.; Iwata, Y.; Himukai, T.; Noda, K.

    2011-12-01

    A raster scanning method has been developed for cancer therapy at NIRS-HIMAC. This method requires a high-accuracy beam current control and fast beam-on/off switching. We have developed a feedback control system of the beam current with the RF-knockout slow extraction method. The system has allowed a stable response to beam-on/off switching using a feedback control delay function with a beam-current ripple of 7%.

  7. Development of beam current control system in RF-knockout slow extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mizushima, K., E-mail: mizshima@nirs.go.jp [Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Science and Technology, Chiba University, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Sato, S.; Shirai, T.; Furukawa, T.; Katagiri, K.; Takeshita, E.; Iwata, Y.; Himukai, T.; Noda, K. [Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2011-12-15

    A raster scanning method has been developed for cancer therapy at NIRS-HIMAC. This method requires a high-accuracy beam current control and fast beam-on/off switching. We have developed a feedback control system of the beam current with the RF-knockout slow extraction method. The system has allowed a stable response to beam-on/off switching using a feedback control delay function with a beam-current ripple of 7%.

  8. Delay Bounds for Multiclass FIFO

    OpenAIRE

    Jiang, Yuming; Misra, Vishal

    2016-01-01

    FIFO is perhaps the simplest scheduling discipline. For single-class FIFO, its delay guarantee performance has been extensively studied: The well-known results include a stochastic delay bound for $GI/GI/1$ by Kingman and a deterministic delay bound for $D/D/1$ by Cruz. However, for multiclass FIFO, few such results are available. To fill the gap, we prove delay bounds for multiclass FIFO in this work, considering both deterministic and stochastic cases. Specifically, delay bounds are present...

  9. A Note on the Sagnac Effect for Matter Beams

    CERN Document Server

    Ruggiero, Matteo Luca

    2014-01-01

    We study the Sagnac effect for matter beams, in order to estimate the kinematic corrections to the basic formula, deriving from the position and the extension of the interferometer, and discuss the analogy with the Aharonov-Bohm effect. We show that the formula for the Sagnac time delay is the same for matter and light beams in arbitrary stationary space-times, provided that a suitable condition on the speed of the beams is fulfilled. Hence, the same results obtained for light beams apply to matter beams.

  10. Growth hormone secretion and clearance rates in growing beef steers implanted with estrogenic anabolic compounds.

    Science.gov (United States)

    Gopinath, R; Kitts, W D

    1984-01-01

    The effect of estrogenic anabolic compounds on the kinetic parameters of metabolism of growth hormone (GH) was studied in growing beef steers. Twenty-four beef steers were randomly placed into four groups and assigned to one of the following four treatment groups: zeranol, diethylstilbestrol (DES), Synovex-S and an unimplanted control. GH metabolism was studied from eight steers on day 20 following the implantation of anabolic compounds. The animals were rapidly injected with a solution of bGH (NIH-GH-B18) and the disappearance of injected GH from the plasma was monitored up to 120 min following the injection. The plasma GH disappearance curve displayed an initial rapid phase lasting 5 min and a slow disappearance phase lasting 42 min; the fractional turnover rate from the two compartments were 0.167 and 0.017 min-1, respectively. The average volume of distribution of GH in steers was 6% of the body weight. Mean values of metabolic clearance and secretion rates of GH in steers were 21 liters/h and 252 micrograms/h or 74.5 ml/kg/h and 0.91 microgram/kg/h, respectively. Steers implanted with anabolic compounds gained more rapidly (P less than 0.05) than the controls. Plasma basal GH concentration appeared to be higher in all the implanted than in the control steers. The secretion rate of GH was increased (P less than 0.05) in steers implanted with anabolic compounds when compared to control steers. The secretion rate (microgram/kg/h) was about 96% (P less than 0.05), 107% (P less than 0.05) and 81% (P less than 0.05) higher in steers implanted with DES, zeranol and Synovex-S, respectively, than in the control steers. All the compounds studied were equally effective in increasing the secretion of GH on day 20 following their implantation. Metabolic clearance rate of GH was not affected by anabolic compound implantation in steers. There was, however, a slight reduction in metabolic clearance rate due to DES and a slight elevation due to zeranol and Synovex-S when

  11. TRACK The New Beam Dynamics Code

    CERN Document Server

    Mustapha, Brahim; Ostroumov, Peter; Schnirman-Lessner, Eliane

    2005-01-01

    The new ray-tracing code TRACK was developed* to fulfill the special requirements of the RIA accelerator systems. The RIA lattice includes an ECR ion source, a LEBT containing a MHB and a RFQ followed by three SC linac sections separated by two stripping stations with appropriate magnetic transport systems. No available beam dynamics code meet all the necessary requirements for an end-to-end simulation of the RIA driver linac. The latest version of TRACK was used for end-to-end simulations of the RIA driver including errors and beam loss analysis.** In addition to the standard capabilities, the code includes the following new features: i) multiple charge states ii) realistic stripper model; ii) static and dynamic errors iii) automatic steering to correct for misalignments iv) detailed beam-loss analysis; v) parallel computing to perform large scale simulations. Although primarily developed for simulations of the RIA machine, TRACK is a general beam dynamics code. Currently it is being used for the design and ...

  12. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne;

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  13. Delayed traumatic diaphragmatic hernia

    Science.gov (United States)

    Lu, Jing; Wang, Bo; Che, Xiangming; Li, Xuqi; Qiu, Guanglin; He, Shicai; Fan, Lin

    2016-01-01

    Abstract Background: Traumatic diaphragmatic hernias (TDHs) are sometimes difficult to identify at an early stage and can consequently result in diagnostic delays with life-threatening outcomes. It is the aim of this case study to highlight the difficulties encountered with the earlier detection of traumatic diaphragmatic hernias. Methods: Clinical data of patients who received treatment for delayed traumatic diaphragmatic hernias in registers of the First Affiliated Hospital of Xi’an Jiaotong University from 1998 to 2014 were analyzed retrospectively. Results: Six patients were included in this study. Left hemidiaphragm was affected in all of them. Most of the patients had a history of traffic accident and 1 a stab-penetrating injury. The interval from injury to developing symptoms ranged from 2 to 11 years (median 5 years). The hernial contents included the stomach, omentum, small intestine, and colon. Diaphragmatic injury was missed in all of them during the initial managements. All patients received operations once the diagnosis of delayed TDH was confirmed, and no postoperative mortality was detected. Conclusions: Delayed TDHs are not common, but can lead to serious consequences once occurred. Early detection of diaphragmatic injuries is crucial. Surgeons should maintain a high suspicion for injuries of the diaphragm in cases with abdominal or lower chest traumas, especially in the initial surgical explorations. We emphasize the need for radiographical follow-up to detect diaphragmatic injuries at an earlier stage. PMID:27512848

  14. 'No delays achiever'.

    Science.gov (United States)

    2007-05-01

    The latest version of the NHS Institute for Innovation and Improvement's 'no delays achiever', a web based tool created to help NHS organisations achieve the 18-week target for GP referrals to first treatment, is available at www.nodelaysachiever.nhs.uk.

  15. Permissible Delay in Payments

    Directory of Open Access Journals (Sweden)

    Yung-Fu Huang

    2007-01-01

    Full Text Available The main purpose of this paper wants to investigate the optimal retailer's lot-sizing policy with two warehouses under partially permissible delay in payments within the economic order quantity (EOQ framework. In this paper, we want to extend that fully permissible delay in payments to the supplier would offer the retailer partially permissible delay in payments. That is, the retailer must make a partial payment to the supplier when the order is received. Then the retailer must pay off the remaining balance at the end of the permissible delay period. In addition, we want to add the assumption that the retailer's storage space is limited. That is, the retailer will rent the warehouse to store these exceeding items when the order quantity is larger than retailer's storage space. Under these conditions, we model the retailer's inventory system as a cost minimization problem to determine the retailer's optimal cycle time and optimal order quantity. Three theorems are developed to efficiently determine the optimal replenishment policy for the retailer. Finally, numerical examples are given to illustrate these theorems and obtained a lot of managerial insights.

  16. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  17. Theoretical and experimental analysis of pulse delay in bacteriorhodopsin films by a saturable absorber theory.

    Science.gov (United States)

    Blaya, Salvador; Candela, Manuel; Acebal, Pablo; Carretero, Luis; Fimia, Antonio

    2014-05-19

    Time-delay of transmitted pulses with respect to the incident pulse in bacteriorhodopsin films has been studied without the use of a pump beam. Based on a modified saturable absorber model, analytical expressions of the transmitted pulse have been obtained. As a result, time delay, distortion and fractional delay have been analyzed for sinusoidal pulses with a low background. A good agreement between theory and experiences has been observed.

  18. True Time Delay Scheme for X-band Phased Array Radar

    Institute of Scientific and Technical Information of China (English)

    LI Zheng

    2007-01-01

    The system of a true-time delay line for X-band and 8-unit phased array antennas is introduced. Changing the length of a chirp grating with piezotranslator(PZT), the variable delay is obtained. The scheme is applied to X-band phased array radar whose searching data rate is 56/s. It is simulated that the beam squinting is influenced by the error of real time delay. The relation between the beamforming mode and its modifying volt is discussed.

  19. Lightweight computational steering of very large scale molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Beazley, D.M. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Computer Science; Lomdahl, P.S. [Los Alamos National Lab., NM (United States)

    1996-09-01

    We present a computational steering approach for controlling, analyzing, and visualizing very large scale molecular dynamics simulations involving tens to hundreds of millions of atoms. Our approach relies on extensible scripting languages and an easy to use tool for building extensions and modules. The system is extremely easy to modify, works with existing C code, is memory efficient, and can be used from inexpensive workstations and networks. We demonstrate how we have used this system to manipulate data from production MD simulations involving as many as 104 million atoms running on the CM-5 and Cray T3D. We also show how this approach can be used to build systems that integrate common scripting languages (including Tcl/Tk, Perl, and Python), simulation code, user extensions, and commercial data analysis packages.

  20. Steering artificial nanoscale swimmers using teardrop shaped posts

    Science.gov (United States)

    Davies Wykes, Megan; Zhong, Xiao; Adachi, Takiji; Liu, Yanpeng; Tong, Jiajun; Ristroph, Leif; Ward, Michael; Zhang, Jun; Shelley, Michael

    2016-11-01

    Microorganisms use various strategies to bias their swimming to achieve long-time directed motion against a flow, against gravity, or up a chemical gradient. To make use of artificial swimmers for transporting cargo, to separate swimming particles from diffusing ones, or to concentrate a solution of motile particles, ways of steering such swimmers are required. We make use of the attraction of artificial bi-metallic swimmers to vertical walls to direct their long-time motion. We will describe how these swimmers are attracted to the surface of teardrop-shaped posts and leave preferentially at regions of higher curvature. We use this understanding to interpret their behavior when interacting with arrays of teardrop-shaped posts. This work was supported partially by the Materials Research Science and Engineering Center (MRSEC) program of the National Science Foundation under Award Number DMR-1420073.