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Sample records for linear drive ka

  1. Linear Back-Drive Differentials

    NASA Technical Reports Server (NTRS)

    Waydo, Peter

    2003-01-01

    Linear back-drive differentials have been proposed as alternatives to conventional gear differentials for applications in which there is only limited rotational motion (e.g., oscillation). The finite nature of the rotation makes it possible to optimize a linear back-drive differential in ways that would not be possible for gear differentials or other differentials that are required to be capable of unlimited rotation. As a result, relative to gear differentials, linear back-drive differentials could be more compact and less massive, could contain fewer complex parts, and could be less sensitive to variations in the viscosities of lubricants. Linear back-drive differentials would operate according to established principles of power ball screws and linear-motion drives, but would utilize these principles in an innovative way. One major characteristic of such mechanisms that would be exploited in linear back-drive differentials is the possibility of designing them to drive or back-drive with similar efficiency and energy input: in other words, such a mechanism can be designed so that a rotating screw can drive a nut linearly or the linear motion of the nut can cause the screw to rotate. A linear back-drive differential (see figure) would include two collinear shafts connected to two parts that are intended to engage in limited opposing rotations. The linear back-drive differential would also include a nut that would be free to translate along its axis but not to rotate. The inner surface of the nut would be right-hand threaded at one end and left-hand threaded at the opposite end to engage corresponding right- and left-handed threads on the shafts. A rotation and torque introduced into the system via one shaft would drive the nut in linear motion. The nut, in turn, would back-drive the other shaft, creating a reaction torque. Balls would reduce friction, making it possible for the shaft/nut coupling on each side to operate with 90 percent efficiency.

  2. Compact 810 kA Linear Transformer Driver Cavity

    NASA Astrophysics Data System (ADS)

    Woodworth, J. R.; Fowler, W. E.; Stoltzfus, B. S.; Stygar, W. A.; Sceiford, M. E.; Mazarakis, M. G.; Anderson, H. D.; Harden, M. J.; Blickem, J. R.; White, R.; Kim, A. A.

    2011-04-01

    We are performing experiments with a 92-kV, 810-kA, 74.6-GW linear transformer driver (LTD) cavity. This cavity generates a ˜100ns power pulse from DC-charged capacitors in a single step. Our experiments start with an existing 100-kV, 490-kA LTD cavity and are making a number of improvements to it that are aimed at increasing the cavity’s peak output power and better understanding its operation. We are making improvements to the gas switches, the capacitors, and the magnetic toroids as well as heavily instrumenting the cavity. These experiments have increased the cavity’s output current into a matched load by 65% without increasing its volume.

  3. 250 kA compact linear transformer driver for wire array z-pinch loads

    NASA Astrophysics Data System (ADS)

    Bott, S. C.; Haas, D. M.; Madden, R. E.; Ueda, U.; Eshaq, Y.; Collins, G., IV; Gunasekera, K.; Mariscal, D.; Peebles, J.; Beg, F. N.; Mazarakis, M.; Struve, K.; Sharpe, R.

    2011-05-01

    We present the application of a short rise (˜150ns) 250 kA linear transformer driver (LTD) to wire array z-pinch loads for the first time. The generator is a modification of a previous driver in which a new conical power feed provides a low inductance coupling to wire loads. Performance of the new design using both short circuit and plasma loads is presented and discussed. The final design delivers ˜200kA to a wire array load which is in good agreement with SCREAMER calculations using a simplified representative circuit. Example results demonstrate successful experiments using cylindrical, conical, and inverse wire arrays as well as previously published work on x-pinch loads.

  4. Proceedings of the international conference on maglev and linear drives

    SciTech Connect

    Not Available

    1986-01-01

    This book contains papers presented at a conference on Maglev and linear drives. Topics covered include: Development of superconducting magnets for the Canadian electrodynamic Maglev vehicle; Power supply system to drive HSST - Expo '86; and Thrust and levitation force characteristics of linear synchronous motors.

  5. Split-Stirling-cycle displacer linear-electric drive

    NASA Technical Reports Server (NTRS)

    Ackermann, R. A.; Bhate, S. K.; Byrne, D. V.

    1983-01-01

    The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

  6. Design of a MeV, 4kA linear induction accelerator for flash radiography

    SciTech Connect

    Kulke, B.; Brier, R.; Chapin, W.

    1981-02-10

    For verifying the hydrodynamics of nuclear weapons design it is useful to have flash x-ray machines that can deliver a maximum dose in a minimum pulse length and with very high reliability. At LLNL, such a requirement was identified some years ago as 500 roentgens at one meter, in a 60 nsec pulse length. In response to this requirement, a linear induction accelerator was proposed to and funded by DOE in 1977. The design of this machine, called FXR, has now been completed and construction has begun. The FXR design extends the parameters of a similar machine that had been built and operated at LBL, Berkeley, some ten years ago. Using a cold cathode injector followed by 48 accelerator modules rated at 400 kV each, the FXR machine will accelerate a 4 kA electron beam pulse to 20 MeV final energy. Key design features are the generation and the stable transport of a low emittance (100 mr-cm) beam from a field emitter diode, the design of reliable, compact energy storage components such as Blumleins, feedlines and accelerator modules, and a computer-assisted control system.

  7. High reliability linear drive device for artificial hearts

    NASA Astrophysics Data System (ADS)

    Ji, Jinghua; Zhao, Wenxiang; Liu, Guohai; Shen, Yue; Wang, Fangqun

    2012-04-01

    In this paper, a new high reliability linear drive device, termed as stator-permanent-magnet tubular oscillating actuator (SPM-TOA), is proposed for artificial hearts (AHs). The key is to incorporate the concept of two independent phases into this linear AH device, hence achieving high reliability operation. The fault-tolerant teeth are employed to provide the desired decoupling phases in magnetic circuit. Also, as the magnets and the coils are located in the stator, the proposed SPM-TOA takes the definite advantages of robust mover and direct-drive capability. By using the time-stepping finite element method, the electromagnetic characteristics of the proposed SPM-TOA are analyzed, including magnetic field distributions, flux linkages, back- electromotive forces (back-EMFs) self- and mutual inductances, as well as cogging and thrust forces. The results confirm that the proposed SPM-TOA meets the dimension, weight, and force requirements of the AH drive device.

  8. A linear chromatic mechanism drives the pupillary response.

    PubMed Central

    Tsujimura, S.; Wolffsohn, J. S.; Gilmartin, B.

    2001-01-01

    Previous studies have shown that a chromatic mechanism can drive pupil responses. The aim of this research was to clarify whether a linear or nonlinear chromatic mechanism drives pupillary responses by using test stimuli of various colours that are defined in cone contrast space. The pupil and accommodation responses evoked by these test stimuli were continuously and simultaneously objectively measured by photorefraction. The results with isochromatic and isoluminant stimuli showed that the accommodative level remained approximately constant (< 0.25 D change in mean level) even when the concurrent pupillary response was large (ca. 0.30 mm). The pupillary response to an isoluminant grating was sustained, delayed (by ca. 60 ms) and larger in amplitude than that for a isochromatic uniform stimulus, which supports previous work suggesting that the chromatic mechanism contributes to the pupillary response. In a second experiment, selected chromatic test gratings were used and isoresponse contours in cone contrast space were obtained. The results showed that the isoresponse contour in cone contrast space is well described (r(2) = 0.99) by a straight line with a positive slope. The results indicate that a /L - M/ linear chromatic mechanism, whereby a signal from the long wavelength cone is subtracted from that of the middle wavelength cone and vice versa, drives pupillary responses. PMID:11674867

  9. Oscillating-Linear-Drive Vacuum Compressor for CO2

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Shimko, Martin

    2005-01-01

    A vacuum compressor has been designed to compress CO2 from approximately equal to 1 psia (approximately equal to 6.9 kPa absolute pressure) to approximately equal to 75 psia (approximately equal to 0.52 MPa), to be insensitive to moisture, to have a long operational life, and to be lightweight, compact, and efficient. The compressor consists mainly of (1) a compression head that includes hydraulic diaphragms, a gas-compression diaphragm, and check valves; and (2) oscillating linear drive that includes a linear motor and a drive spring, through which compression force is applied to the hydraulic diaphragms. The motor is driven at the resonance vibrational frequency of the motor/spring/compression-head system, the compression head acting as a damper that takes energy out of the oscillation. The net effect of the oscillation is to cause cyclic expansion and contraction of the gas-compression diaphragm, and, hence, of the volume bounded by this diaphragm. One-way check valves admit gas into this volume from the low-pressure side during expansion and allow the gas to flow out to the high-pressure side during contraction. Fatigue data and the results of diaphragm stress calculations have been interpreted as signifying that the compressor can be expected to have an operational life of greater than 30 years with a confidence level of 99.9 percent.

  10. Aluminum and tungsten X-pinch experiments on 100 kA, 100 ns linear transformer driver stage

    SciTech Connect

    Wu Jian; Sun Tieping; Wu Gang; Wang Liangping; Han Juanjuan; Li Mo; Cong Peitian; Qiu Aici; Lv Min

    2011-05-15

    X-pinch experiments have been carried out on a 100 kA, 100 ns linear transformer driver stage recently built up. The X-pinches exhibited a source size of about 10 {mu}m, a pulse duration of 3 ns, 3-5 keV radiation energy of 3.9 mJ, and a burst time jitter of tens of nanosecond with the 2-wire 8 {mu}m W X-pinch load. The generator output current and the X-pinch characteristics depended on the X-pinch wire materials in the tests. X-ray backlighting images from the insects showed the significant phase-contrast effect.

  11. Evolution from MEMS-based Linear Drives to Bio-based Nano Drives

    NASA Astrophysics Data System (ADS)

    Fujita, Hiroyuki

    The successful extension of semiconductor technology to fabricate mechanical parts of the sizes from 10 to 100 micrometers opened wide ranges of possibilities for micromechanical devices and systems. The fabrication technique is called micromachining. Micromachining processes are based on silicon integrated circuits (IC) technology and used to build three-dimensional structures and movable parts by the combination of lithography, etching, film deposition, and wafer bonding. Microactuators are the key devices allowing MEMS to perform physical functions. Some of them are driven by electric, magnetic, and fluidic forces. Some others utilize actuator materials including piezoelectric (PZT, ZnO, quartz) and magnetostrictive materials (TbFe), shape memory alloy (TiNi) and bio molecular motors. This paper deals with the development of MEMS based microactuators, especially linear drives, following my own research experience. They include an electrostatic actuator, a superconductive levitated actuator, arrayed actuators, and a bio-motor-driven actuator.

  12. Linear free-energy relationships between a single gas-phase ab initio equilibrium bond length and experimental pKa values in aqueous solution.

    PubMed

    Alkorta, Ibon; Popelier, Paul L A

    2015-02-01

    Remarkably simple yet effective linear free energy relationships were discovered between a single ab initio computed bond length in the gas phase and experimental pKa values in aqueous solution. The formation of these relationships is driven by chemical features such as functional groups, meta/para substitution and tautomerism. The high structural content of the ab initio bond length makes a given data set essentially divide itself into high correlation subsets (HCSs). Surprisingly, all molecules in a given high correlation subset share the same conformation in the gas phase. Here we show that accurate pKa values can be predicted from such HCSs. This is achieved within an accuracy of 0.2 pKa units for 5 drug molecules.

  13. Linear hydraulic drive system for a Stirling engine

    DOEpatents

    Walsh, Michael M.

    1984-02-21

    A hydraulic drive system operating from the periodic pressure wave produced by a Stirling engine along a first axis thereof and effecting transfer of power from the Stirling engine to a load apparatus therefor and wherein the movable, or working member of the load apparatus is reciprocatingly driven along an axis substantially at right angles to the first axis to achieve an arrangement of a Stirling engine and load apparatus assembly which is much shorter and the components of the load apparatus more readily accessible.

  14. The 13th International Conference on Magnetically Levitated Systems and Linear Drives MAGLEV 1993

    NASA Astrophysics Data System (ADS)

    This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.

  15. 13th International Conference on Magnetically Levitated Systems and Linear Drives

    SciTech Connect

    Not Available

    1993-09-01

    This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.

  16. Computer Synthesis Approaches of Hyperboloid Gear Drives with Linear Contact

    NASA Astrophysics Data System (ADS)

    Abadjiev, Valentin; Kawasaki, Haruhisa

    2014-09-01

    The computer design has improved forming different type software for scientific researches in the field of gearing theory as well as performing an adequate scientific support of the gear drives manufacture. Here are attached computer programs that are based on mathematical models as a result of scientific researches. The modern gear transmissions require the construction of new mathematical approaches to their geometric, technological and strength analysis. The process of optimization, synthesis and design is based on adequate iteration procedures to find out an optimal solution by varying definite parameters. The study is dedicated to accepted methodology in the creation of soft- ware for the synthesis of a class high reduction hyperboloid gears - Spiroid and Helicon ones (Spiroid and Helicon are trademarks registered by the Illinois Tool Works, Chicago, Ill). The developed basic computer products belong to software, based on original mathematical models. They are based on the two mathematical models for the synthesis: "upon a pitch contact point" and "upon a mesh region". Computer programs are worked out on the basis of the described mathematical models, and the relations between them are shown. The application of the shown approaches to the synthesis of commented gear drives is illustrated.

  17. Nonlinear response of a linear chain to weak driving

    NASA Astrophysics Data System (ADS)

    Hennig, D.; Mulhern, C.; Burbanks, A. D.; Schimansky-Geier, L.

    2014-01-01

    We study the escape of a chain of coupled units over the barrier of a metastable potential. It is demonstrated that a very weak external driving field with a suitably chosen frequency suffices to accomplish speedy escape. The latter requires passage through a transition state, the formation of which is triggered by permanent feeding of energy from a phonon background into humps of localized energy and elastic interaction of the arising breather solutions. In fact, cooperativity between the units of the chain entailing coordinated energy transfer is shown to be crucial for enhancing the rate of escape in an extremely effective and low-energy cost way where the effects of entropic localization and breather coalescence conspire.

  18. Improved linear ultrasonic motor performance with square-wave based driving-tip trajectory

    NASA Astrophysics Data System (ADS)

    Le, Adam Y.; Mills, James K.; Benhabib, Beno

    2015-03-01

    This paper proposes the application of a non-sinusoidal periodic excitation voltage to induce a near-square-wave driving tip trajectory in linear ultrasonic motors (LUSMs). A square-wave-based trajectory can deliver superior frictional force to the moving stage in the forward stroke of the driving tip motion and reduced frictional force during the return stroke. This would reduce lost power in the periodic driving tip motion, thereby, increasing the output force and power of the LUSM. An implementation procedure is suggested to achieve the near-square-wave driving tip trajectory. The proposed approach is illustrated through realistic finite-element-based simulations using a bimodal LUSM configuration.

  19. Forces driving late Pleistocene (ca. 77-12 ka) landscape evolution in the Cimarron River valley, southwestern Kansas

    NASA Astrophysics Data System (ADS)

    Layzell, Anthony L.; Mandel, Rolfe D.; Ludvigson, Greg A.; Rittenour, Tammy M.; Smith, Jon J.

    2015-07-01

    This study presents stratigraphic, geomorphic, and paleoenvironmental (δ13C) data that provide insight into the late Pleistocene landscape evolution of the Cimarron River valley in the High Plains of southwestern Kansas. Two distinct valley fills (T-1 and T-2) were investigated. Three soils occur in the T-2 fill and five in the T-1 fill, all indicating periods of landscape stability or slow sedimentation. Of particular interest are two cumulic soils dating to ca. 48-28 and 13-12.5 ka. δ13C values are consistent with regional paleoenvironmental proxy data that indicate the prevalence of warm, dry conditions at these times. The Cimarron River is interpreted to have responded to these climatic changes and to local base level control. Specifically, aggradation occurred during cool, wet periods and slow sedimentation with cumulic soil formation occurred under warmer, drier climates. Significant valley incision (~ 25 m) by ca. 28 ka likely resulted from a lowering of local base level caused by deep-seated dissolution of Permian evaporite deposits.

  20. Linear Stepper Actuation Driving Drop Resonance and Modifying Hysteresis.

    PubMed

    Katariya, Mayur; Huynh, So Hung; McMorran, Darren; Lau, Chun Yat; Muradoglu, Murat; Ng, Tuck Wah

    2016-08-23

    In this work, 2 μL water drops are placed on substrates that are created to have a circular hydrophilic region bounded by superhydrophobicity so that they exhibit high contact angles. When the substrate is translated by a linear stepper actuator, the random force components present in the actuator are shown to cause the drop to rock resonantly. When the substrate is translated downward at inclination angles of up to 6° with respect to the horizontal, the contact angle hysteresis increases progressively to a limiting condition. When the substrate is moved up at inclined angles, alternatively, the contact angle hysteresis increases initially to the limiting condition before it is progressively restored to its static state. These behaviors are accounted for by the reversible micro-Cassie to Wenzel wetting state transformations that are made possible by the hierarchical microscale and nanoscale structures present in the superhydrophobic regions.

  1. Solar receiver heliostat reflector having a linear drive and position information system

    DOEpatents

    Horton, Richard H.

    1980-01-01

    A heliostat for a solar receiver system comprises an improved drive and control system for the heliostat reflector assembly. The heliostat reflector assembly is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, i.e., heat receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system. The improved drive system includes linear stepping motors which comprise low weight, low cost, electronic pulse driven components. One embodiment comprises linear stepping motors controlled by a programmed, electronic microprocessor. Another embodiment comprises a tape driven system controlled by a position control magnetic tape.

  2. Experiments investigating the generation and transport of 10--12 MeV, 30-kA, mm-size electron beams with linear inductive voltage adders

    SciTech Connect

    Mazarakis, M.G.; Poukey, J.W.; Maenchen, J.E.

    1997-06-01

    The authors present the design, analysis, and results of the high-brightness electron beam experiments currently under investigation at Sandia National Laboratories. The anticipated beam parameters are the following: 8--12 MeV, 35--50 kA, 30--60 ns FWHM, and 0.5-mm rms beam radius. The accelerators utilized are SABRE and HERMES III. Both are linear inductive voltage adders modified to higher impedance and fitted with magnetically immersed foil less electron diodes. In the strong 20--50 Tesla solenoidal magnetic field of the diode, mm-size electron beams are generated and propagated to a beam stop. The electron beam is field emitted from mm-diameter needle-shaped cathode electrode and is contained in a similar size envelop by the strong magnetic field. These extremely space charge dominated beams provide the opportunity to study beam dynamics and possible instabilities in a unique parameter space. The SABRE experiments are already completed and have produced 30-kA, 1.5-mm FWHM electron beams, while the HERMES-III experiments are on-going.

  3. Drive Control of an Electric Vehicle by a Non-linear Controller

    NASA Astrophysics Data System (ADS)

    Mubin, Marizan; Ouchi, Shigeto; Anabuki, Masatoshi; Hirata, Hiroshi

    The driving force of automobiles is transmitted by the frictional force between the tires and the road surface. This frictional force is a function of the weight of the car-body and the friction coefficient μ between the tires and the road surface. The friction coefficient μ is also a function of the following parameters: the slip ratio λ determined by the car-body speed and the wheel speed, and the condition of the road surface. Slippage of automobiles which causes much damage often occurs during accelerating and braking. In this paper, we propose a new drive control system which has an effect on acceleration and braking. In the drive control system, a non-linear controller designed by using a Lyapunov function is used. This non-linear controller has two functions: first one is μ control which moves the car-body, another one is λ control. The controller is designed in order that μ and λ work at noslip and with slip respectively. As another controller, a disturbance observer is used for estimating the car-body speed which is difficult to be measured. Then, this lead to the proof of the stability condition of the combined system which consists of two controllers: the non-linear controller and the disturbance observer. Finally, the effectiveness of this control system is proved by a very satisfactory simulation and experimental results for two cases.

  4. Magnetic evaluation of advanced metal-evaporated tape in an advanced linear tape drive

    NASA Astrophysics Data System (ADS)

    Alfano, Anthony D.; Bhushan, Bharat

    2007-01-01

    Demand for increased data storage has resulted in the development of various types of magnetic tapes. To achieve higher recording density, tape manufacturers are developing thin-film tapes, such as advanced metal-evaporated (AME) tape, for use in linear tape drives. In recent studies, these new AME tapes have demonstrated sustainable mechanical durability at low tensions suitable for use in linear tape drives. An evaluation of the magnetic performance of these AME tapes including the impact of tape cupping and initial edge quality was the goal of this study. Head output, dropouts, head-tape interface friction, and lateral tape motion (LTM) were monitored throughout testing. As track widths continue to narrow, LTM has become one of the critical limitations of magnetic performance. To more accurately measure LTM during drive development, a new method involving the output voltage of a head-read element that has been adjusted to be halfway off the recorded track on tape was implemented (LTM M). It is shown that positively cupped AME tapes will result in similar head output and fewer dropouts than the current MP tapes. The negatively cupped AME sample produced the lowest head output data and the highest amount of dropouts of all the tapes evaluated in this investigation. All the tapes evaluated demonstrated similar values of LTM when monitored at the center of the tape. When LTM was monitored at the lower edge of the tape, the positively cupped AME tape with the worst relative edge contour length resulted in the highest LTM M. As found in previous studies, AME tapes produced slightly lower values of coefficient of friction than the MP tapes. From this investigation, positively cupped AME tapes with good initial relative edge contour length are recommended for use in linear tape drives, similar to those used in this study.

  5. Beam dynamics design of the Compact Linear Collider Drive Beam injector

    NASA Astrophysics Data System (ADS)

    Hajari, Sh. Sanaye; Shaker, H.; Doebert, S.

    2015-11-01

    In the Compact Linear Collider (CLIC) the RF power for the acceleration of the Main Beam is extracted from a high-current Drive Beam that runs parallel to the main linac. The longitudinal and transverse beam dynamics of the Drive Beam injector has been studied in detail and optimized. The injector consists of a thermionic gun followed by a bunching system, some accelerating structures, and a magnetic chicane. The bunching system contains three sub-harmonic bunchers, a prebuncher, and a traveling wave buncher all embedded in a solenoidal magnetic field. The main characteristic of the Drive Beam injector is the phase coding process done by the sub-harmonic bunching system operating at half the acceleration frequency. This process is essential for the frequency multiplication of the Drive Beam. During the phase coding process the unwanted satellite bunches are produced that adversely affects the machine power efficiency. The main challenge is to reduce the population of particles in the satellite bunches in the presence of strong space-charge forces due to the high beam current. The simulation of the beam dynamics has been carried out with PARMELA with the goal of optimizing the injector performance compared to the existing model studied for the Conceptual Design Report (CDR). The emphasis of the optimization was on decreasing the satellite population, the beam loss in the magnetic chicane and limiting the beam emittance growth in transverse plane.

  6. A Novel MagPipe Pipeline transportation system using linear motor drives

    SciTech Connect

    Fang, J.R.; Montgomery, D.B.; Roderick, L.

    2009-11-15

    A novel capsule pipeline transportation system using linear motor drives, called Magplane MagPipe, is under development with the intention to replace trucks and railways for hauling materials from the mine to the rail head, power plant, or processing plant with reduced operating cost and energy consumption. The initial demonstration of a MagPipe line in Inner Mongolia will be a 500-m-long double-pipe coal transport system with the design transportation capacity of 3 Mega-Mg per year. The pipeline consists of 6-m-long plastic pipe modules with an I-beam suspension system inside the pipe to carry sets of five coupled capsules. The pipe will also contain noncontinuous motor winding modules spaced at 50-m intervals. A set of Halbach-arrayed permanent magnets on the bottom of the capsules interact with the linear motor windings to provide propulsion. The motor is driven by variable frequency drives outside the pipe to control the speed. This paper briefly describes the overall MagPipe pipeline transportation system, including the preliminary conclusions of the linear synchronous motor analysis.

  7. Tape edge study in a linear tape drive with single-flanged guides

    NASA Astrophysics Data System (ADS)

    Goldade, Anton V.; Bhushan, Bharat

    2004-05-01

    Improved tape guiding and tape dimensional stability are essential for magnetic tape linear recoding formats to take advantage of vastly increased track density and thereby achieve higher storage capacities. Tape guiding is dependent on numerous parameters, such as type of the guides and tape path geometry, quality of virgin tape edge, drive operating parameters (e.g., tape speed and tape tension), mechanical properties of the tape, and tape geometry (e.g., cupping and curvature). The objective of the present study is to evaluate guiding and tribological performance of single-flanged guides with porous air bearings in a linear tape drive. A comparison of guiding performance of the dual flanged stationary guides and single-flanged guides with porous air bearings is performed. The effect of tape path geometry, drive operating conditions (speed and tension) and tape edge quality of factory-slit tapes on tape guiding are evaluated during short-term tests. A lateral force measurement technique is used to measure the force exerted by the tape edge on the guide flange. A technique for the lateral tape motion measurement is used to study the effect of continuous sliding on tape guiding. Wear tests up to 5000 cycles are conducted and coefficient of friction and lateral tape motion are monitored to study the effect of drive operating conditions (speed and tension), edge quality of factory-slit tapes and tape thickness on tape guiding. Optical microscopy, atomic force microscopy and scanning electron microscopy are employed to study and quantify the quality of tape edge.

  8. Controllability of Free-piston Stirling Engine/linear Alternator Driving a Dynamic Load

    NASA Technical Reports Server (NTRS)

    Kankam, M. David; Rauch, Jeffrey S.

    1994-01-01

    This paper presents the dynamic behavior of a Free-Piston Stirling Engine/linear alternator (FPSE/LA) driving a single-phase fractional horse-power induction motor. The controllability and dynamic stability of the system are discussed by means of sensitivity effects of variations in system parameters, engine controller, operating conditions, and mechanical loading on the induction motor. The approach used expands on a combined mechanical and thermodynamic formulation employed in a previous paper. The application of state-space technique and frequency domain analysis enhances understanding of the dynamic interactions. Engine-alternator parametric sensitivity studies, similar to those of the previous paper, are summarized. Detailed discussions are provided for parametric variations which relate to the engine controller and system operating conditions. The results suggest that the controllability of a FPSE-based power system is enhanced by proper operating conditions and built-in controls.

  9. A rectangle-type linear ultrasonic motor using longitudinal vibration transducers with four driving feet.

    PubMed

    Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

    2013-04-01

    To make full use of the vibrational energy of a longitudinal transducer, a rectangle-type linear ultrasonic motor with four driving feet is proposed in this paper. This new motor consists of four longitudinal vibration transducers which are arranged in a rectangle and form an enclosed construction. Lead zirconate titanate ceramics are embedded into the middle of the transducer and fastened by a wedge-caulking mechanism. Each transducer includes an exponentially shaped horn located on each end. The horns of the vertical transducers intersect at the base of the horizontal transducers' horns; the tip ends of the horizontal transducers' horns are used as the driving feet. Longitudinal vibrations are superimposed in the motor and generate elliptical movements at the tip ends of the horns. The working principle of the proposed motor is analyzed. The resonance frequencies of two working modes are tuned to be close to each other by adjusting the structural parameters. Transient analysis is developed to gain the vibration characteristics of the motor. A prototype motor is fabricated and measured. The vibration test results verify the feasibility of the proposed design. Typical output of the prototype is a no-load speed of 928 mm/s and maximum thrust force of 60 N at a voltage of 200 Vrms.

  10. Development of an ultrasonic linear motor with ultra-positioning capability and four driving feet.

    PubMed

    Zhu, Cong; Chu, Xiangcheng; Yuan, Songmei; Zhong, Zuojin; Zhao, Yanqiang; Gao, Shuning

    2016-12-01

    This paper presents a novel linear piezoelectric motor which is suitable for rapid ultra-precision positioning. The finite element analysis (FEA) was applied for optimal design and further analysis, then experiments were conducted to investigate its performance. By changing the input signal, the proposed motor was found capable of working in the fast driving mode as well as in the precision positioning mode. When working in the fast driving mode, the motor acts as an ultrasonic motor with maximum no-load speed up to 181.2mm/s and maximum thrust of 1.7N at 200Vp-p. Also, when working in precision positioning mode, the motor can be regarded as a flexible hinge piezoelectric actuator with arbitrary motion in the range of 8μm. The measurable minimum output displacement was found to be 0.08μm, but theoretically, can be even smaller. More importantly, the motor can be quickly and accurately positioned in a large stroke.

  11. Development of an ultrasonic linear motor with ultra-positioning capability and four driving feet.

    PubMed

    Zhu, Cong; Chu, Xiangcheng; Yuan, Songmei; Zhong, Zuojin; Zhao, Yanqiang; Gao, Shuning

    2016-12-01

    This paper presents a novel linear piezoelectric motor which is suitable for rapid ultra-precision positioning. The finite element analysis (FEA) was applied for optimal design and further analysis, then experiments were conducted to investigate its performance. By changing the input signal, the proposed motor was found capable of working in the fast driving mode as well as in the precision positioning mode. When working in the fast driving mode, the motor acts as an ultrasonic motor with maximum no-load speed up to 181.2mm/s and maximum thrust of 1.7N at 200Vp-p. Also, when working in precision positioning mode, the motor can be regarded as a flexible hinge piezoelectric actuator with arbitrary motion in the range of 8μm. The measurable minimum output displacement was found to be 0.08μm, but theoretically, can be even smaller. More importantly, the motor can be quickly and accurately positioned in a large stroke. PMID:27479230

  12. Torque linearizing hardware for the electric joint motors of a direct-drive robot

    SciTech Connect

    Muir, P.F.; Bryan, J.R.

    1991-12-31

    Many emerging high-performance robot control algorithms require the command of the joint torques; yet no known commercial robots provide such a capability. In this paper, we describe the design, development, testing and application of a VMEbus-based torque linearizing joint interface board (JIB). One JIB resides between the robot control processor and each joint motor amplifier. The JIB provides the control processor with the capability to read the motor position and apply accurate motor torques. The torque command capability derives from the application of a 128k {times} 8 EPROM lookup table for each motor phase. Because joint motor torque is dependent upon the torque command and the motor position, the hardware is designed to utilize the torque command and the current motor position as the address to retrieve the proper pulse-width for the PWM motor amplifier. The table look-up cycle operates independently of the robot controller at a 40KHz rate to provide constant joint torque as the motor rotates. We identify the proper table entries by an automated in situ data collection procedure. Static torque generation results show that the torque deviations are reduced from as much as 76% to below 5% for each of the three direct-drive motors (two are variable reluctance motors and one is brushless DC) on an AdeptTwo robot. These torque deviations are reduced below 2.5% if only the upper 90% of the torque range is considered. The torque deviations of the non-direct-drive joint are reduced by 50%. Dynamic robot edge following experiments show that the robot speed of operation can be more than doubled for a given applied force accuracy by utilizing the joint torque linearizing boards. 8 refs.

  13. Torque linearizing hardware for the electric joint motors of a direct-drive robot

    SciTech Connect

    Muir, P.F.; Bryan, J.R.

    1991-01-01

    Many emerging high-performance robot control algorithms require the command of the joint torques; yet no known commercial robots provide such a capability. In this paper, we describe the design, development, testing and application of a VMEbus-based torque linearizing joint interface board (JIB). One JIB resides between the robot control processor and each joint motor amplifier. The JIB provides the control processor with the capability to read the motor position and apply accurate motor torques. The torque command capability derives from the application of a 128k {times} 8 EPROM lookup table for each motor phase. Because joint motor torque is dependent upon the torque command and the motor position, the hardware is designed to utilize the torque command and the current motor position as the address to retrieve the proper pulse-width for the PWM motor amplifier. The table look-up cycle operates independently of the robot controller at a 40KHz rate to provide constant joint torque as the motor rotates. We identify the proper table entries by an automated in situ data collection procedure. Static torque generation results show that the torque deviations are reduced from as much as 76% to below 5% for each of the three direct-drive motors (two are variable reluctance motors and one is brushless DC) on an AdeptTwo robot. These torque deviations are reduced below 2.5% if only the upper 90% of the torque range is considered. The torque deviations of the non-direct-drive joint are reduced by 50%. Dynamic robot edge following experiments show that the robot speed of operation can be more than doubled for a given applied force accuracy by utilizing the joint torque linearizing boards. 8 refs.

  14. Torque linearizing hardware for the electric joint motors of a direct-drive robot

    NASA Astrophysics Data System (ADS)

    Muir, P. F.; Bryan, J. R.

    Many emerging high-performance robot control algorithms require the command of the joint torques, yet no known commercial robots provide such a capability. We describe the design, development, testing, and application of a VMEbus-based torque linearizing joint interface board (JIB). One JIB resides between the robot control processor and each joint motor amplifier. The JIB provides the control processor with the capability to read the motor position and apply accurate motor torques. The torque command capability derives from the application of a 128k x 8 EPROM lookup table for each motor phase. Because joint motor torque is dependent upon the torque command and the motor position, the hardware is designed to utilize the torque command and the current motor position as the address to retrieve the proper pulse-width for the PWM motor amplifier. The table look-up cycle operates independently of the robot controller at a 40KHz rate to provide constant joint torque as the motor rotates. We identify the proper table entries by an automated in situ data collection procedure. Static torque generation results show that the torque deviations are reduced from as much as 76 percent to below 5 percent for each of the three direct-drive motors (two are variable reluctance motors and one is brushless DC) on an AdeptTwo robot. These torque deviations are reduced below 2.5 percent if only the upper 90 percent of the torque range is considered. The torque deviations of the non-direct-drive joint are reduced by 50 percent. Dynamic robot edge following experiments show that the robot speed of operation can be more than doubled for a given applied force accuracy by utilizing the joint torque linearizing boards.

  15. Linear motor drive system for continuous-path closed-loop position control of an object

    DOEpatents

    Barkman, William E.

    1980-01-01

    A precision numerical controlled servo-positioning system is provided for continuous closed-loop position control of a machine slide or platform driven by a linear-induction motor. The system utilizes filtered velocity feedback to provide system stability required to operate with a system gain of 100 inches/minute/0.001 inch of following error. The filtered velocity feedback signal is derived from the position output signals of a laser interferometer utilized to monitor the movement of the slide. Air-bearing slides mounted to a stable support are utilized to minimize friction and small irregularities in the slideway which would tend to introduce positioning errors. A microprocessor is programmed to read command and feedback information and converts this information into the system following error signal. This error signal is summed with the negative filtered velocity feedback signal at the input of a servo amplifier whose output serves as the drive power signal to the linear motor position control coil.

  16. Design, analysis and experimental performance of a stepping type piezoelectric linear actuator based on compliant foot driving

    NASA Astrophysics Data System (ADS)

    Wang, Shupeng; Rong, Weibin; Wang, Lefeng; Sun, Lining

    2016-11-01

    A stepping type piezoelectric linear actuator based on compliant foot driving is proposed in this paper. With the help of four piezo-stacks and four compliant feet, the designed actuator can produce large range linear motions in both positive and negative directions with high accuracy. The mechanical structure and the operating principle are discussed. Mohr integration method is used to analyze the deformation of the key component compliant foot. To investigate the working performance, a prototype is fabricated and a series of experiments are carried out. The experimental results indicate that the displacement outputs under various driving voltages and various driving frequencies show good linear relationships with the time. The driving resolution and the maximum output force are 10.98 nm and 43 N, respectively. The displacements deviation between the forward and backward motions within 30 steps is 6.82 μm and the amplitude of the parasitic motions is about 0.638 μm. The experimental results also confirm that the designed actuator can achieve various speeds by changing the driving voltage and driving frequency.

  17. NDT and SHM of Carbon Fiber Composites using Linear Drive MWM-Arrays

    NASA Technical Reports Server (NTRS)

    Washabaugh, Andrew; Martin, Christopher; Lyons, Robert; Grundy, David; Goldfine, Neil; Russell, Richard; Wincheski, Russell

    2012-01-01

    Carbon fiber composites are used in a wide range of structural applications due to their excellent specific strength and stiffness. However, the anisotropic mechanical and electrical properties associated with the fibers within each composite layer present challenges, and opportunities, for Nondestructive Testing (NDT) methods used to characterize and assess the structure condition. This includes composite condition after manufacture (such as fiber orientation and density, porosity, delamination, and bond strength) and during usage (such as damage from impact, fiber breakage, thermal exposure or applied stress). Ultrasonic and thermographic methods can address some of these challenges, but eddy current methods provide an alternative method for composite structures that contain a conducting material, such as carbon fibers or a metallic liner. This presentation reviews recent advances in the development of eddy current sensors and arrays for carbon fiber composite NDT and Structural Health Monitoring (SHM) applications. The focus is on eddy current sensor constructs with linear drive windings, such as MWM -Arrays, that induce currents primarily within the linear fibers of the composite. By combining this type of sensor construct with micromechanical models that relate composite constituent properties to measurable sensor responses, insight is obtained into the volumetric distribution of electrical properties within the composite and the associated manufacturing, damage, or strain conditions. With knowledge of the fiber layup, this MWM-Array technology is able to detect damage and strain/stress as a function of depth and fiber orientation. This work has been funded by NASA, NA V AIR and the Army for applications ranging from composite overwrapped pressure vessels (COPVs) to aircraft structures and rotorcraft blades. This presentation will specifically present background on the MWM-Array technology, results from the micromechanical modeling effort, and results from

  18. Single-Phase Drive Ultrasonic Linear Motor Using a Linked Twin Square Plate Vibrator

    NASA Astrophysics Data System (ADS)

    Yokoyama, Keiji; Tamura, Hideki; Masuda, Kentaro; Takano, Takehiro

    2013-07-01

    A novel linear motion ultrasonic motor, which uses a single resonance mode driven by a single phase and has the same motor characteristics for operation in reverse directions, is developed. An in-plane breathing mode in the square plate is strongly driven by the transverse effect of a piezoelectric ceramic. A stator resonator consists of twin square plates linked by V-shaped beams. Only one side of the square plate can be excited by the resonance of the breathing mode, when the other passive side plate is electrically opened so that the effective elasticities and the resonant frequencies between both plates are different; as a result, the friction edge of the resonator vibrates in a slant locus to move a load slider. The reverse operation is easily obtained by switching the driving side of the square plates. We designed the stator resonator by FEM analysis and fabricated a prototype for our experiment. The prototype motor showed good characteristics, for example, a moving slider velocity of 100 mm/s, a thrust force of 3.5 N, and an efficiency of 30% when the preload was 10 N, the input effective voltage was 5 V, and the input power was 1.2 W.

  19. Adaptive hybrid control for linear piezoelectric ceramic motor drive using diagonal recurrent CMAC network.

    PubMed

    Wai, Rong-Jong; Lin, Chih-Min; Peng, Ya-Fu

    2004-11-01

    This paper presents an adaptive hybrid control system using a diagonal recurrent cerebellar-model-articulation-computer (DRCMAC) network to control a linear piezoelectric ceramic motor (LPCM) driven by a two-inductance two-capacitance (LLCC) resonant inverter. Since the dynamic characteristics and motor parameters of the LPCM are highly nonlinear and time varying, an adaptive hybrid control system is therefore designed based on a hypothetical dynamic model to achieve high-precision position control. The architecture of DRCMAC network is a modified model of a cerebellar-model-articulation-computer (CMAC) network to attain a small number of receptive-fields. The novel idea of this study is that it employs the concept of diagonal recurrent neural network (DRNN) in order to capture the system dynamics and convert the static CMAC into a dynamic one. This adaptive hybrid control system is composed of two parts. One is a DRCMAC network controller that is used to mimic a conventional computed torque control law due to unknown system dynamics, and the other is a compensated controller with bound estimation algorithm that is utilized to recover the residual approximation error for guaranteeing the stable characteristic. The effectiveness of the proposed driving circuit and control system is verified with hardware experiments under the occurrence of uncertainties. In addition, the advantages of the proposed control scheme are indicated in comparison with a traditional integral-proportional (IP) position control system.

  20. Non-linear effects in electron cyclotron current drive applied for the stabilization of neoclassical tearing modes

    NASA Astrophysics Data System (ADS)

    Ayten, B.; Westerhof, E.; the ASDEX Upgrade Team

    2014-07-01

    Due to the smallness of the volumes associated with the flux surfaces around the O-point of a magnetic island, the electron cyclotron power density applied inside the island for the stabilization of neoclassical tearing modes (NTMs) can exceed the threshold for non-linear effects as derived previously by Harvey et al (1989 Phys. Rev. Lett. 62 426). We study the non-linear electron cyclotron current drive (ECCD) efficiency through bounce-averaged, quasi-linear Fokker-Planck calculations in the magnetic geometry as created by the islands. The calculations are performed for the parameters of a typical NTM stabilization experiment on ASDEX Upgrade. A particular feature of these experiments is that the rays of the EC wave beam propagate tangential to the flux surfaces in the power deposition region. The calculations show significant non-linear effects on the ECCD efficiency, when the ECCD power is increased from its experimental value of 1 MW to a larger value of 4 MW. The nonlinear effects are largest in the case of locked islands or when the magnetic island rotation period is longer than the collisional time scale. The non-linear effects result in an overall reduction of the current drive efficiency for this case with absorption of the EC power on the low-field side of the electron cyclotron resonance layer. As a consequence of the non-linear effects, also the stabilizing effect of the ECCD on the island is reduced from linear expectations.

  1. Quasi-linear modeling of lower hybrid current drive in ITER and DEMO

    SciTech Connect

    Cardinali, A. Cesario, R.; Panaccione, L.; Santini, F.; Amicucci, L.; Castaldo, C.; Ceccuzzi, S.; Mirizzi, F.; Tuccillo, A. A.

    2015-12-10

    First pass absorption of the Lower Hybrid waves in thermonuclear devices like ITER and DEMO is modeled by coupling the ray tracing equations with the quasi-linear evolution of the electron distribution function in 2D velocity space. As usually assumed, the Lower Hybrid Current Drive is not effective in a plasma of a tokamak fusion reactor, owing to the accessibility condition which, depending on the density, restricts the parallel wavenumber to values greater than n{sub ∥crit} and, at the same time, to the high electron temperature that would enhance the wave absorption and then restricts the RF power deposition to the very periphery of the plasma column (near the separatrix). In this work, by extensively using the “ray{sup star}” code, a parametric study of the propagation and absorption of the LH wave as function of the coupled wave spectrum (as its width, and peak value), has been performed very accurately. Such a careful investigation aims at controlling the power deposition layer possibly in the external half radius of the plasma, thus providing a valuable aid to the solution of how to control the plasma current profile in a toroidal magnetic configuration, and how to help the suppression of MHD mode that can develop in the outer part of the plasma. This analysis is useful not only for exploring the possibility of profile control of a pulsed operation reactor as well as the tearing mode stabilization, but also in order to reconsider the feasibility of steady state regime for DEMO.

  2. Proceedings of the IEEE international conference on Maglev and linear drives

    SciTech Connect

    Not Available

    1987-01-01

    These proceedings collect papers on linear induction motors and magnetic levitation. Topics include: linear induction propulsion, eddy current analysis of cryostat outer vessel in superconductive magnetically levitated vehicles, dynamics of maglev vehicles, and high-speed maglev trains.

  3. Dynamics of a belt-drive system using a linear complementarity problem for the belt pulley contact description

    NASA Astrophysics Data System (ADS)

    Čepon, Gregor; Boltežar, Miha

    2009-01-01

    The aim of this study was to develop an efficient and realistic numerical model in order to predict the dynamic response of belt drives. The belt was modeled as a planar beam element based on an absolute nodal coordinate formulation. A viscoelastic material was adopted for the belt and the corresponding damping and stiffness matrices were determined. The belt-pulley contact was formulated as a linear complementarity problem together with a penalty method. This made it possible for us to accurately predict the contact forces, including the stick and slip zones between the belt and the pulley. The belt-drive model was verified by comparing it with the available analytical solutions. A good agreement was found. Finally, the applicability of the method was demonstrated by considering non-steady belt-drive operating conditions.

  4. Ka-band study: 1988

    NASA Technical Reports Server (NTRS)

    Layland, J. W.; Horttor, R. L.; Clauss, R. C.; Wilcher, J. H.; Wallace, R. J.; Mudgway, D. J.

    1989-01-01

    The Ka-band study team was chartered in late 1987 to bring together all the planning elements for establishing 32 GHz (Ka-band) as the primary downlink frequency for deep-space operation, and to provide a stable baseline from which to pursue that development. This article summarizes the results of that study at its conclusion in mid-1988, and corresponds to material presented to NASA's Office of Space Operations on July 14, 1988. For a variety of reasons, Ka-band is the right next major step in deep-space communications. It offers improved radio metric accuracy through reduced plasma sensitivity and increased bandwidth. Because of these improvements, it offers the opportunity to reduce costs in the flight radio system or in the DSN by allocating part of the overall benefits of Ka-band to this cost reduction. A mission scenario is being planned that can drive at least two and possibly all three of the DSN subnets to provide a Ka-band downlink capability by the turn of the century. The implementation scenario devised by the study team is believed to be feasible within reasonable resource expectations, and capable of providing the needed upgrade as a natural follow-on to the technology development which is already underway.

  5. Optimizing the driving function for nonequilibrium free-energy calculations in the linear regime: a variational approach.

    PubMed

    de Koning, Maurice

    2005-03-01

    We consider the issue of optimizing linear-regime nonequilibrium simulations to estimate free-energy differences. In particular, we focus on the problem of finding the best-possible driving function lambda(t) that, for a given thermodynamic path, simulation algorithm, and amount of computational effort, minimizes dissipation. From the fluctuation-dissipation theorem it follows that, in the linear-response regime, the dissipation is controlled by the magnitude and characteristic correlation time of the equilibrium fluctuations in the driving force. As a result, the problem of finding the optimal switching scheme involves the solution of a standard problem in variational calculus: the minimization of a functional with respect to the switching function. In practice, the minimization involves solving the associated Euler-Lagrange equation subject to a set of boundary conditions. As a demonstration we apply the approach to the simple, yet illustrative problem of computing the free-energy difference between two classical harmonic oscillators with very different characteristic frequencies.

  6. Non-Linear Effects on the LH Wave Coupling in Tore Supra and Impact on the LH Current Drive Efficiency

    SciTech Connect

    Ekedahl, A.; Frincu, B.; Goniche, M.; Hillairet, J.; Petrzilka, V.

    2009-11-26

    A strong, non-linear degradation of the Lower Hybrid (LH) wave coupling in Tore Supra can be observed when the LH launcher is screened on both sides by additional side limiters, such as side protections of adjacent Ion Cyclotron (IC) antennas. The power reflection coefficient (RC) at the LH grill mouth is estimated to increase from {approx}20% at low power density (<1 MW/m{sup 2}) up to >40% at high power density (>10 MW/m{sup 2}). Such large RC (>40%) is unacceptably high, in particular for long durations. The screening by the additional side limiters reduces the connection length in front of the LH grill, which results in lower {lambda}{sub n}, {lambda}{sub T}, n{sub e} and T{sub e} at the grill. However, the reduction in ne alone is not enough to explain the non-linear behaviour. Modelling with a code that takes into account a ponderomotive force potential [1], depleting the electron density in front of the grill, shows consistent results. In full non-inductive current drive scenarios, the observed degradation in LH coupling is measurable on the LH current drive efficiency, through the increase in coupled LH power required to maintain V{sub Loop} = 0. These results demonstrate thus the importance of being able to control the LH coupling conditions, in order to optimize the efficiency and power handling of LH systems.

  7. Experimental characterization and modelling of non-linear coupling of the lower hybrid current drive power on Tore Supra

    NASA Astrophysics Data System (ADS)

    Preynas, M.; Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A.; Colas, L.

    2013-01-01

    To achieve steady-state operation on future fusion devices, in particular on ITER, the coupling of the lower hybrid wave must be optimized on a wide range of edge conditions. However, under some specific conditions, deleterious effects on the lower hybrid current drive (LHCD) coupling are sometimes observed on Tore Supra. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the fully active multi-junction (FAM) and the new passive active multi-junction (PAM) antennas. A non-linear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient (RC) with the LHCD power is not predicted by the standard linear theory of the LH wave coupling. A theoretical model is suggested to describe the non-linear wave-plasma interaction induced by the ponderomotive effect and implemented in a new full wave LHCD code, PICCOLO-2D (ponderomotive effect in a coupling code of lower hybrid wave-2D). The code self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density. The simulation reproduces very well the occurrence of a non-linear behaviour in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive modelling for the first time on the FAM and PAM antennas on Tore Supra.

  8. Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values.

    PubMed

    Rasouli, Zolaikha; Ghavami, Raouf

    2016-08-01

    Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD=0.12], 0.67-23.19 [LOD=0.13] and 0.73-25.12 [LOD=0.15] μgmL(-1) for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples. PMID:27176001

  9. Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values

    NASA Astrophysics Data System (ADS)

    Rasouli, Zolaikha; Ghavami, Raouf

    2016-08-01

    Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD = 0.12], 0.67-23.19 [LOD = 0.13] and 0.73-25.12 [LOD = 0.15] μg mL- 1 for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples.

  10. Amplitude modulation drive to rectangular-plate linear ultrasonic motors with vibrators dimensions 8 mm x 2.16 mm X 1 mm.

    PubMed

    Ming, Yang; Hanson, Ben; Levesley, Martin C; Walker, Peter G; Watterson, Kevin G

    2006-12-01

    In this paper, to exploit the contribution from not only the stators but also from other parts of miniature ultrasonic motors, an amplitude modulation drive is proposed to drive a miniature linear ultrasonic motor consisting of two rectangular piezoelectric ceramic plates. Using finite-element software, the first longitudinal and second lateral-bending frequencies of the vibrator are shown to be very close when its dimensions are 8 mm x 2.16 mm x 1 mm. So one single frequency power should be able to drive the motor. However, in practice the motor is found to be hard to move with a single frequency power because of its small vibration amplitudes and big frequency difference between its longitudinal and bending resonance, which is induced by the boundary condition variation. To drive the motor effectively, an amplitude modulation drive is used by superimposing two signals with nearly the same frequencies, around the resonant frequency of the vibrators of the linear motor. When the amplitude modulation frequency is close to the resonant frequency of the vibrator's surroundings, experimental results show that the linear motor can move back and forward with a maximum thrust force (over 0.016 N) and a maximum velocity (over 50 mm/s).

  11. Characterising the interaction of individual-wheel drives with traction by linear parameter-varying model: a method for analysing the role of traction in torsional vibrations in wheel drives and active damping

    NASA Astrophysics Data System (ADS)

    Zhun Yeap, Khang; Müller, Steffen

    2016-02-01

    A model-based approach for characterising the interaction of individual-wheel drives with traction is contributed in this article. The primary aim is to investigate the influence of traction on torsional vibration behaviour in the drive train. The essence of this approach lies in reformulating the nonlinear traction behaviour into its differential form, which enables an analytical description of this interaction in its linear parameter-varying model equivalence. Analytical statements on the vibration behaviour for different driving scenarios are inferred from this model and validated with measurement samples from a high-performance electric road vehicle. Subsequent influences of traction on the performance of active damping of torsional vibrations are derived from this model.

  12. Dual-drive LiNbO3 interferometric Mach-Zehnder architecture with extended linear regime for high peak-to-average OFDM-based communication systems.

    PubMed

    Morant, Maria; Llorente, Roberto; Hauden, Jerome; Quinlan, Terence; Mottet, Alexandre; Walker, Stuart

    2011-12-12

    A dual-drive LiNbO(3) architecture modulator with chirp management is proposed and developed offering SFDR > 25 dB in a 1.4 V bias excursion compared to only 0.5 V bias excursion in a conventional Mach-Zehnder electro-optical modulator (MZ-EOM). The architecture effectively extends the linear regime and enables the optical transmission of wireless systems employing orthogonal division multiplexing (OFDM) modulation such as ultra-wide band (UWB) which require high linearity over a broad frequency range due to their high peak-to-average power ratio (PARP). Radio-over-fiber UWB transmission in a passive optical network is experimentally demonstrated employing this technique, exhibiting an enhancement of 2.2 dB in EVM after 57 km SSMF when the dual-drive developed modulator is employed. PMID:22274055

  13. JINR test facility for studies FEL bunching technique for CLIC driving beam

    SciTech Connect

    Dolbilov, G.V.; Fateev, A.A.; Ivanov, I.N.

    1995-12-31

    SILUND-21 linear induction accelerator (energy up to 10 MeV, peak current about of 1 kA, pulse duration 50 - 70 ns) is constructed at JINR in the framework of experimental program to study free electron laser physics, a problem of two-beam acceleration and microwave electronics. In this paper we present project of an experiment to adopt the FEL bunching technique for generation of the CLIC driving beam.

  14. Ka Band Objects: Observation and Monitoring (KaBOOM)

    NASA Astrophysics Data System (ADS)

    Geldzahler, B.

    2012-09-01

    NASA has embarked on a path that will enable the implementation of a high power, high resolution X/Ka band radar system using widely spaced 12m antennas to better track and characterize near Earth objects and orbital debris. This radar system also has applications for cost effective space situational awareness. We shall demonstrate Ka band coherent uplink arraying with real-time atmospheric compensation using three 12m antennas at the Kennedy Space Center (KSC). Our proposed radar system can complement and supplement the activities of the Space Fence. The proposed radar array has the advantages of filling the gap between dusk and dawn and offers the possibility of high range resolution (4 cm) and high spatial resolution (?10 cm at GEO) when used in a VLBI mode. KSC was chosen because [a] of reduced implementation costs, [b] there is a lot of water vapor in the air (not Ka band friendly), and [c] the test satellites have a low elevation adding more attenuation and turbulence to the demonstration. If Ka band coherent uplink arraying can be made to work at KSC, it will work anywhere. We expect to rebaseline X-band in 2013, and demonstrate Ka band uplink arraying in 2014.

  15. Electric versus hydraulic drives

    SciTech Connect

    Not Available

    1983-01-01

    This volume records the proceedings of a conference organised by the Engineering Manufacturing Industries Division of the Institution of Mechanical Engineers. Topics considered include high performance position control - a review of the current state of developments; hydrostatic drives - present and future; electric drives - present and future trends; electrical and hydraulic drives for heavy industrial robots; the development of an electro-mechanical tilt system for the advanced passenger train; industrial hydraulic ring mains - effective or efficient. the comparison of performance of servo feed-drive systems; overhead crane drives; the future of d.c. servodrives; the choice of actuator for military systems; linear electro-hydraulic actuators; and actuation for industrial robots.

  16. Multipurpose 5-MeV linear induction accelerator

    NASA Astrophysics Data System (ADS)

    Birx, D. L.; Hawkins, S. A.; Poor, S. E.; Reginato, L. L.; Smith, M. W.

    1984-06-01

    Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, new technology was used to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The magnetic drive system are tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization.

  17. Multipurpose 5-MeV linear induction accelerator

    SciTech Connect

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L. Smith, M.W.

    1984-06-11

    Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, the researchers used new technology to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The paper describes the scheme. The magnetic drive system can be tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization.

  18. Electrothermal linear actuator

    NASA Technical Reports Server (NTRS)

    Derr, L. J.; Tobias, R. A.

    1969-01-01

    Converting electric power into powerful linear thrust without generation of magnetic fields is accomplished with an electrothermal linear actuator. When treated by an energized filament, a stack of bimetallic washers expands and drives the end of the shaft upward.

  19. Rationalization of the pKa values of alcohols and thiols using atomic charge descriptors and its application to the prediction of amino acid pKa's.

    PubMed

    Ugur, Ilke; Marion, Antoine; Parant, Stéphane; Jensen, Jan H; Monard, Gerald

    2014-08-25

    In a first step toward the development of an efficient and accurate protocol to estimate amino acids' pKa's in proteins, we present in this work how to reproduce the pKa's of alcohol and thiol based residues (namely tyrosine, serine, and cysteine) in aqueous solution from the knowledge of the experimental pKa's of phenols, alcohols, and thiols. Our protocol is based on the linear relationship between computed atomic charges of the anionic form of the molecules (being either phenolates, alkoxides, or thiolates) and their respective experimental pKa values. It is tested with different environment approaches (gas phase or continuum solvent-based approaches), with five distinct atomic charge models (Mulliken, Löwdin, NPA, Merz-Kollman, and CHelpG), and with nine different DFT functionals combined with 16 different basis sets. Moreover, the capability of semiempirical methods (AM1, RM1, PM3, and PM6) to also predict pKa's of thiols, phenols, and alcohols is analyzed. From our benchmarks, the best combination to reproduce experimental pKa's is to compute NPA atomic charge using the CPCM model at the B3LYP/3-21G and M062X/6-311G levels for alcohols (R(2) = 0.995) and thiols (R(2) = 0.986), respectively. The applicability of the suggested protocol is tested with tyrosine and cysteine amino acids, and precise pKa predictions are obtained. The stability of the amino acid pKa's with respect to geometrical changes is also tested by MM-MD and DFT-MD calculations. Considering its strong accuracy and its high computational efficiency, these pKa prediction calculations using atomic charges indicate a promising method for predicting amino acids' pKa in a protein environment.

  20. Rationalization of the pKa values of alcohols and thiols using atomic charge descriptors and its application to the prediction of amino acid pKa's.

    PubMed

    Ugur, Ilke; Marion, Antoine; Parant, Stéphane; Jensen, Jan H; Monard, Gerald

    2014-08-25

    In a first step toward the development of an efficient and accurate protocol to estimate amino acids' pKa's in proteins, we present in this work how to reproduce the pKa's of alcohol and thiol based residues (namely tyrosine, serine, and cysteine) in aqueous solution from the knowledge of the experimental pKa's of phenols, alcohols, and thiols. Our protocol is based on the linear relationship between computed atomic charges of the anionic form of the molecules (being either phenolates, alkoxides, or thiolates) and their respective experimental pKa values. It is tested with different environment approaches (gas phase or continuum solvent-based approaches), with five distinct atomic charge models (Mulliken, Löwdin, NPA, Merz-Kollman, and CHelpG), and with nine different DFT functionals combined with 16 different basis sets. Moreover, the capability of semiempirical methods (AM1, RM1, PM3, and PM6) to also predict pKa's of thiols, phenols, and alcohols is analyzed. From our benchmarks, the best combination to reproduce experimental pKa's is to compute NPA atomic charge using the CPCM model at the B3LYP/3-21G and M062X/6-311G levels for alcohols (R(2) = 0.995) and thiols (R(2) = 0.986), respectively. The applicability of the suggested protocol is tested with tyrosine and cysteine amino acids, and precise pKa predictions are obtained. The stability of the amino acid pKa's with respect to geometrical changes is also tested by MM-MD and DFT-MD calculations. Considering its strong accuracy and its high computational efficiency, these pKa prediction calculations using atomic charges indicate a promising method for predicting amino acids' pKa in a protein environment. PMID:25089727

  1. Ka-band MMIC subarray technology program (Ka-Mist)

    NASA Technical Reports Server (NTRS)

    Pottenger, Warren

    1995-01-01

    The broad objective of this program was to demonstrate a proof of concept insertion of Monolithic Microwave Integrated Circuit (MMIC) device technology into an innovative (tile architecture) active phased array antenna application supporting advanced EHF communication systems. Ka-band MMIC arrays have long been considered as having high potential for increasing the capability of space, aircraft, and land mobile communication systems in terms of scan performance, data rate, link margin, and flexibility while offering a significant reduction in size, weight, and power consumption. Insertion of MMIC technology into antenna systems, particularly at millimeter wave frequencies using low power and low noise amplifiers in close proximity to the radiating elements, offers a significant improvement in the array transmit efficiency, receive system noise figure, and overall array reliability. Application of active array technology also leads to the use of advanced beamforming techniques that can improve beam agility, diversity, and adaptivity to complex signal environments.

  2. Fade Mitigation Techniques at Ka-Band

    NASA Technical Reports Server (NTRS)

    Dissanayake, Asoka (Editor)

    1996-01-01

    Rain fading is the dominant propagation impairment affecting Ka-band satellite links and rain fade mitigation is a key element in the design of Ka-band satellite networks. Some of the common fade mitigation techniques include: power control, diversity, adaptive coding, and resource sharing. The Advanced Communications Technology Satellite (ACTS) provides an excellent opportunity to develop and test Ka-band rain impairment amelioration techniques. Up-link power control and diversity are discussed in this paper.

  3. KaVA ESTEMA project

    NASA Astrophysics Data System (ADS)

    Oyadomari, Miyako; Imai, Hiroshi; Cho, Se-Hyung; Asaki, Yoshiharu; Choi, Yoon-Kyong; Kim, Jaeheon; Yun, Youngjoo; Matsumoto, Naoko; Min, Cheul-Hong; Oyama, Tomoaki; Yoon, Sung-Chul; Yoon, Dong-Hwan; Kim, Dong-Jin; Dodson, Richard; Rioja, Maria; Burns, Ross; Orosz, Gabor; Nakagawa, Akiharu; Chibueze O, James; Nakashima, Jun-ichi; Sobolev, Andrey

    2016-07-01

    The ESTEMA (Expanded Study on Stellar Masers) project is one of three Large Programs of the KaVA (the combined array of the Korean VLBI Network and Japanese VLBI Exploration of Radio Astrometry), and conducted in 2015-2016. It aims to publish a database of the largest sample of VLBI images of circumstellar water (H2O) and silicon-monoxide (SiO) maser sources towards circumstellar envelopes (CSEs) of 80 evolved stars in late AGB to early post-AGB phase. Here we present the specifications of the ESTEMA observations and the planned scientific goals in order to share the basic information of the ESTEMA with astronomical community and encourage future collaborations with the ESTEMA and future follow-up observations for the targeted stars.

  4. Fault tolerant linear actuator

    DOEpatents

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  5. SARAL/AltiKa Project Overview

    NASA Astrophysics Data System (ADS)

    Picot, Nicolas; Sengenes, Pierre; Lambin, Juliette; Noubel, Jocelyne; Mazeau, Sophie; Verron, Jacques

    2015-04-01

    The SARAL-AltiKa satellite mission is an India-France ISRO-CNES joint project. The satellite has been put into orbit by a PSLV vehicle supplied by ISRO, and launched from Sriharikota, the main ISRO launch base, on Feb. 25, 2013. The SARAL (Satellite for ARgos and ALtika) payload consists of an ARGOS instrument, and an altimetry payload including the AltiKa radiometer-altimeter. SARAL/AltiKa is intended to be a gap filler mission between the RA-2 on-board ENVISAT and Sentinel-3. As such, SARAL/AltiKa is flying on the same orbit as ENVISAT. The special feature of SARAL/AltiKa is mainly related to a wideband Ka-band altimeter (35.75 GHz, 500 MHz), which is the very first satellite altimeter dedicated to oceanography to operate at such a high frequency. The AltiKa instrument consists in a Ka-band altimeter based on already developed subsystems inherited from Siral (CRYOSAT) and Poseidon-3 (JASON-2) in particular, and an embedded dual frequency radiometer. The altimeter and the radiometer share the same antenna. Due to the single frequency Ka-band altimeter, the enhanced bandwidth leads to a better vertical resolution. The spatial resolution is also improved, thanks to the Ka-band smaller footprint and the increased PRF. This talk will present the main characteristics of the mission and the main outcome regarding the data availability and overall quality after 2 years of mission. In particular, we will focus on the main advantages and/or drawbacks of the Ka band frequency compared to the classical Ku band used on other missions like Jason-2. A specific point will be performed on the rain attenuation and corresponding impacts on the altimeter data quality.

  6. Formation of a 100-kA tokamak discharge in the Princeton large torus by lower hybrid waves

    SciTech Connect

    Jobes, F.; Stevens, J.; Bell, R.; Bernabei, S.; Cavallo, A.; Chu, T.K.; Cohen, S.; Denne, B.; Efthimion, P.; Hinnov, E.

    1984-03-01

    The development of non-inductive current drive is of great importance in establishing the tokamak as a long-pulse or steady-state fusion reactor. Lower hybrid waves, carrying 200 kW of power at 800 MHz, have been launched into the PLT tokamak to initiate and drive the discharge current to a level in excess of 100 kA.

  7. Linear mass actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)

    1992-01-01

    A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.

  8. Ka-Band MMIC Subarray Technology Program (Ka-Mist)

    NASA Technical Reports Server (NTRS)

    Pottinger, W.

    1995-01-01

    Ka-band monolithic microwave integrated circuit (MMIC) arrays have been considered as having high potential for increasing the capability of space, aircraft, and land mobile communication systems in terms of scan performance, data rate, link margin, and flexibility while offering a significant reduction in size, weight, and power consumption. Insertion of MMIC technology into antenna systems, particularly at millimeter wave frequencies using low power and low noise amplifiers in closed proximity to the radiating elements, offers a significant improvement in the array transmit efficiency, receive system noise figure, and overall array reliability. Application of active array technology also leads to the use of advanced beamforming techniques that can improve beam agility, diversity, and adaptivity to complex signal environments. The objective of this program was to demonstrate the technical feasibility of the 'tile' array packaging architecture at EHF via the insertion of 1990 MMIC technology into a functional tile array or subarray module. The means test of this objective was to demonstrate and deliver to NASA a minimum of two 4 x 4 (16 radiating element) subarray modules operating in a transmit mode at 29.6 GHz. Available (1990) MMIC technology was chosen to focus the program effort on the novel interconnect schemes and packaging requirements rather than focusing on MMIC development. Major technical achievements of this program include the successful integration of two 4 x 4 subarray modules into a single antenna array. This 32 element array demonstrates a transmit EIRP of over 300 watts yielding an effective directive power gain in excess of 55 dB at 29.63 GHz. The array has been actively used as the transmit link in airborne/terrestrial mobile communication experiments accomplished via the ACTS satellite launched in August 1993.

  9. Sequenced drive for rotary valves

    DOEpatents

    Mittell, Larry C.

    1981-01-01

    A sequenced drive for rotary valves which provides the benefits of applying rotary and linear motions to the movable sealing element of the valve. The sequenced drive provides a close approximation of linear motion while engaging or disengaging the movable element with the seat minimizing wear and damage due to scrubbing action. The rotary motion of the drive swings the movable element out of the flowpath thus eliminating obstruction to flow through the valve.

  10. Mars Global Surveyor Ka-Band Frequency Data Analysis

    NASA Technical Reports Server (NTRS)

    Morabito, D.; Butman, S.; Shambayati, S.

    2000-01-01

    environment for the feed and electronics equipment. A dichroic plate is used to reflect the X-band energy and pass the Ka-band energy to another mirror. The RF energy for each band is then focused onto a feed horn and low-noise amplifier package. After amplification and RF/IF downconversion, the IF signals are sent to the Experimental Tone Tracker (ETT), a digital phase-lock-loop receiver, which simultaneously tracks both X-band and Ka-band carrier signals. Once a signal is detected, the ETT outputs estimates of the SNR in a I -Hz bandwidth (Pc/No), baseband phase and frequency of the signals every I -sec. Between December 1996 and December 1998, the Ka-band and X-band signals from MGS were tracked on a regular basis using the ETT. The Ka-band downlink frequencies described here were referenced to the spacecraft's on-board USO which was also the X-band frequency reference (f(sub ka)= 3.8 f(sub x)). The ETT estimates of baseband phase at I -second sampled time tags were converted to sky frequency estimates. Frequency residuals were then generated for each band by removing a model frequency from each observable frequency at each time tag. The model included Doppler and other effects derived from spacecraft trajectory files obtained from the MGS Navigation Team. A simple troposphere correction was applied to the data. In addition to residuals, the USO frequencies emitted by the spacecraft were estimated. For several passes, the USO frequencies were determined from X-band data and from Ka-band data (referred to X-band by dividing by 3.8) and were found to be in good agreement. In addition, X-band USO frequency estimates from MGS Radio Science data acquired from operational DSN stations were available for comparison and were found to agree within the I Hz level. The remaining sub-Hertz differences were attributed to the different models and software algorithms used by MGS Radio Science and KaBLE-11. A summary of the results of a linear fit of the USO frequency versus time (day of

  11. iDriving (Intelligent Driving)

    2012-09-17

    iDriving identifies the driving style factors that have a major impact on fuel economy. An optimization framework is used with the aim of optimizing a driving style with respect to these driving factors. A set of polynomial metamodels is constructed to reflect the responses produced in fuel economy by changing the driving factors. The optimization framework is used to develop a real-time feedback system, including visual instructions, to enable drivers to alter their driving stylesmore » in responses to actual driving conditions to improve fuel efficiency.« less

  12. Base drive circuit

    DOEpatents

    Lange, Arnold C.

    1995-01-01

    An improved base drive circuit (10) having a level shifter (24) for providing bistable input signals to a pair of non-linear delays (30, 32). The non-linear delays (30, 32) provide gate control to a corresponding pair of field effect transistors (100, 106) through a corresponding pair of buffer components (88, 94). The non-linear delays (30, 32) provide delayed turn-on for each of the field effect transistors (100, 106) while an associated pair of transistors (72, 80) shunt the non-linear delays (30, 32) during turn-off of the associated field effect transistor (100, 106).

  13. Base drive circuit

    DOEpatents

    Lange, A.C.

    1995-04-04

    An improved base drive circuit having a level shifter for providing bistable input signals to a pair of non-linear delays. The non-linear delays provide gate control to a corresponding pair of field effect transistors through a corresponding pair of buffer components. The non-linear delays provide delayed turn-on for each of the field effect transistors while an associated pair of transistors shunt the non-linear delays during turn-off of the associated field effect transistor. 2 figures.

  14. Drugged Driving

    MedlinePlus

    ... Infographics » Drugged Driving Drugged Driving Email Facebook Twitter Text Description of Infographic Top Right Figure : In 2009, ... crash than those who don't smoke. Bottom Text: Develop Social Strategies Offer to be a designated ...

  15. Impaired Driving

    MedlinePlus

    ... Risk Factors BAC Effects Prevention Additional Resources How big is the problem? In 2014, 9,967 people ... Driving: A Threat to Everyone (October 2011) Additional Data Drunk Driving State Data and Maps Motor Vehicle ...

  16. Mars Global Surveyor Ka-Band Frequency Data Analysis

    NASA Astrophysics Data System (ADS)

    Morabito, D.; Butman, S.; Shambayati, S.

    2000-01-01

    for the feed and electronics equipment. A dichroic plate is used to reflect the X-band energy and pass the Ka-band energy to another mirror. The RF energy for each band is then focused onto a feed horn and low-noise amplifier package. After amplification and RF/IF downconversion, the IF signals are sent to the Experimental Tone Tracker (ETT), a digital phase-lock-loop receiver, which simultaneously tracks both X-band and Ka-band carrier signals. Once a signal is detected, the ETT outputs estimates of the SNR in a I -Hz bandwidth (Pc/No), baseband phase and frequency of the signals every I -sec. Between December 1996 and December 1998, the Ka-band and X-band signals from MGS were tracked on a regular basis using the ETT. The Ka-band downlink frequencies described here were referenced to the spacecraft's on-board USO which was also the X-band frequency reference (fka= 3.8 fx). The ETT estimates of baseband phase at I -second sampled time tags were converted to sky frequency estimates. Frequency residuals were then generated for each band by removing a model frequency from each observable frequency at each time tag. The model included Doppler and other effects derived from spacecraft trajectory files obtained from the MGS Navigation Team. A simple troposphere correction was applied to the data. In addition to residuals, the USO frequencies emitted by the spacecraft were estimated. For several passes, the USO frequencies were determined from X-band data and from Ka-band data (referred to X-band by dividing by 3.8) and were found to be in good agreement. In addition, X-band USO frequency estimates from MGS Radio Science data acquired from operational DSN stations were available for comparison and were found to agree within the I Hz level. The remaining sub-Hertz differences were attributed to the different models and software algorithms used by MGS Radio Science and KaBLE-11. A summary of the results of a linear fit of the USO frequency versus time (day of year) is

  17. Hosing Instability of the Drive Electron Beam in the E157 Plasma-Wakefield Acceleration Experiment at the Stanford Linear Accelerator

    SciTech Connect

    Blue, Brent Edward; /SLAC /UCLA

    2005-10-10

    In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 {micro}m/{delta}{sub z} at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 ({approx}2 x 10{sup 14} cm{sup -3}), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt.

  18. Sea surface temperatures in the North Atlantic Ocean from 30ka to 10ka

    NASA Astrophysics Data System (ADS)

    Barrack, Kerr; Greenop, Rosanna; Burke, Andrea; Barker, Stephen; Chalk, Thomas; Crocker, Anya

    2016-04-01

    Some of the most striking features of the Late Pleistocene interval are the rapid changes in climate between warmer interstadial and cold stadial periods which, when coupled, are termed Dansgaard-Oeschger (D-O) events. This shift between warm and cold climates has been interpreted to result from changes in the thermohaline circulation (Broecker et al., 1985) triggered by, for instance, freshwater input from the collapse of the Laurentide ice sheet (Zahn et al., 1997). However, a recent study suggests that major ice rafting events cannot be the 'trigger' for the centennial to millennial scale cooling events identified over the past 500kyr (Barker at al., 2015). Polar planktic foraminiferal and lithogenic/terrigenous grain counts reveal that the southward migration of the polar front occurs before the deposition of ice rafted debris and therefore the rafting of ice during stadial periods. Based upon this evidence, Barker et al. suggest that the transition to a stadial state is a non-linear response to gradual cooling in the region. In order to test this hypothesis, our study reconstructs sea surface temperature across D-O events and the deglaciation in the North Atlantic between 30ka and 10ka using Mg/ Ca paleothermometry in Globigerina bulloides at ODP Sites 980 and 983 (the same sites as used in Barker et al., 2015) with an average sampling resolution of 300 years. With our new record we evaluate the timing of surface ocean temperature change, frontal shift movement, and ice rafting to investigate variations in the temperature gradient across the polar front over D-O events. References: Barker, S., Chen, J., Gong, X., Jonkers, L., Knorr, G., Thornalley, D., 2015. Icebergs not the trigger for North Atlantic cold events. Nature, 520(7547), pp.333-336. Broecker, W.S., Peteer, D.M., Rind, D., 1985. Does the ocean-atmosphere system have more than one stable mode of operation? Nature, 315 (6014), pp.21-26. Zahn, R., Schönfeld, J., Kudrass, H.-R., Park, M

  19. Pile Driving

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  20. First-principles calculation of pKa for cocaine, nicotine, neurotransmitters, and anilines in aqueous solution.

    PubMed

    Lu, Haiting; Chen, Xi; Zhan, Chang-Guo

    2007-09-01

    The absolute pKa values of 24 representative amine compounds, including cocaine, nicotine, 10 neurotransmitters, and 12 anilines, in aqueous solution were calculated by performing first-principles electronic structure calculations that account for the solvent effects using four different solvation models, i.e., the surface and volume polarization for electrostatic interaction (SVPE) model, the standard polarizable continuum model (PCM), the integral equation formalism for the polarizable continuum model (IEFPCM), and the conductor-like screening solvation model (COSMO). Within the examined computational methods, the calculations using the SVPE model lead to the absolute pKa values with the smallest root-mean-square-deviation (rmsd) value (1.18). When the SVPE model was replaced by the PCM, IEFPCM, and COSMO, the rmsd value of the calculated absolute pKa values became 3.21, 2.72, and 3.08, respectively. All types of calculated pKa values linearly correlate with the experimental pKa values very well. With the empirical corrections using the linear correlation relationships, the theoretical pKa values are much closer to the corresponding experimental data and the rmsd values become 0.51-0.83. The smallest rmsd value (0.51) is also associated with the SVPE model. All of the results suggest that the first-principles electronic structure calculations using the SVPE model are a reliable approach to the pKa prediction for the amine compounds. PMID:17691837

  1. First-principles calculation of pKa for cocaine, nicotine, neurotransmitters, and anilines in aqueous solution

    PubMed Central

    Lu, Haiting; Chen, Xi; Zhan, Chang-Guo

    2010-01-01

    The absolute pKa values of 24 representative amine compounds, including cocaine, nicotine, 10 neurotransmitters, and 12 anilines, in aqueous solution were calculated by performing first-principles electronic structure calculations that account for the solvent effects using four different solvation models, i.e. the surface and volume polarization for electrostatic interaction (SVPE) model, the standard polarizable continuum model (PCM), the integral equation formalism for the polarizable continuum model (IEFPCM), and the conductor-like screening solvation model (COSMO). Within the examined computational methods, the calculations using the SVPE model lead to the absolute pKa values with the smallest root-mean-square-deviation (RMSD) value (1.18). When the SVPE model was replaced by the PCM, IEFPCM, and COSMO, the RMSD value of the calculated absolute pKa values became 3.21, 2.72, and 3.08, respectively. All types of calculated pKa values linearly correlate with the experimental pKa values very well. With the empirical corrections using the linear correlation relationships, the theoretical pKa values are much closer to the corresponding experimental data and the RMSD values become 0.51 to 0.83. The smallest RMSD value (0.51) is also associated with the SVPE model. All of the results suggest that the first-principles electronic structure calculations using the SVPE model are a reliable approach to the pKa prediction for the amine compounds. PMID:17691837

  2. Ka-Band, Multi-Gigabit-Per-Second Transceiver

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Wintucky, Edwin G.; Smith, Francis J.; Harris, Johnny M.; Landon, David G.; Haddadin, Osama S.; McIntire, William K.; Sun, June Y.

    2011-01-01

    A document discusses a multi-Gigabit-per-second, Ka-band transceiver with a software-defined modem (SDM) capable of digitally encoding/decoding data and compensating for linear and nonlinear distortions in the end-to-end system, including the traveling-wave tube amplifier (TWTA). This innovation can increase data rates of space-to-ground communication links, and has potential application to NASA s future spacebased Earth observation system. The SDM incorporates an extended version of the industry-standard DVB-S2, and LDPC rate 9/10 FEC codec. The SDM supports a suite of waveforms, including QPSK, 8-PSK, 16-APSK, 32- APSK, 64-APSK, and 128-QAM. The Ka-band and TWTA deliver an output power on the order of 200 W with efficiency greater than 60%, and a passband of at least 3 GHz. The modem and the TWTA together enable a data rate of 20 Gbps with a low bit error rate (BER). The payload data rates for spacecraft in NASA s integrated space communications network can be increased by an order of magnitude (>10 ) over current state-of-practice. This innovation enhances the data rate by using bandwidth-efficient modulation techniques, which transmit a higher number of bits per Hertz of bandwidth than the currently used quadrature phase shift keying (QPSK) waveforms.

  3. Distracted Driving

    MedlinePlus

    ... combines all three types of distraction. 3 How big is the problem? Deaths In 2013, 3,154 ... European countries. More A CDC study analyzed 2011 data on distracted driving, including talking on a cell ...

  4. Ka-me: a Voronoi image analyzer

    PubMed Central

    Khiripet, Noppadon; Khantuwan, Wongarnet; Jungck, John R.

    2012-01-01

    Summary: Ka-me is a Voronoi image analyzer that allows users to analyze any image with a convex polygonal tessellation or any spatial point distribution by fitting Voronoi polygons and their dual, Delaunay triangulations, to the pattern. The analytical tools include a variety of graph theoretic and geometric tools that summarize the distribution of the numbers of edges per face, areas, perimeters, angles of Delaunay triangle edges (anglograms), Gabriel graphs, nearest neighbor graphs, minimal spanning trees, Ulam trees, Pitteway tests, circumcircles and convexhulls, as well as spatial statistics (Clark–Evans Nearest Neighborhood and Variance to Mean Ratio) and export functions for standard relationships (Lewis's Law, Desch's Law and Aboav–Weaire Law). Availability: Ka-me: a Voronoi image analyzer is available as an executable with documentation and sample applications from the BioQUEST Library (http://bioquest.org/downloads/kame_1.0.rar). Contact: noppadon.khiripet@nectec.or.th PMID:22556369

  5. Microwave spectrum of the Ka = 1 ←

    NASA Astrophysics Data System (ADS)

    Karyakin, E. N.; Fraser, G. T.; Suenram, R. D.

    A 78-118 GHz synthesizer-driven backward-wave oscillator is used together with klystron sources and frequency doublers to measure the electric-resonance optothermal spectrum of the Ka = 1 ← 0 rotation-tunnelling subband of (D2O)2. Transitions are observed originating from each of the six tunnelling states, A+1, B+1, E+1, A-2, B-2, and E-2, allowing an estimate of the largest tunnelling matrix element h4v, characterizing the separation of the A+1, B+1, and E+1 states from the A-2, B-2, and E-2 states. We find the average of h4v for the Ka = 0 and 1 states to be ˜ -8 943 MHz. A comparison of the Ka = 1 ← 0 band origins for the A/B states with the band origin for their E partner gives h2v ˜ -6·9 MHz, where h2v is the tunnelling matrix element responsible for the displacement of the E symmetry levels from the center of their interconversion split A/B partners. Values found for the A rotational constant, A ˜ 124 923 MHz, and h2v are in good agreement with those obtained from the submillimetre measurements of Zwart, E., ter Meulen, J. J., and Meerts, W. L., 1990, Chem. Phys. Lett., 173, 115, on the Ka = 2 ← 1 band of the complex. Estimates are presented for the potential barriers to the 1 → 2, 1 → 5 and 1 → 7 tunnelling processes.

  6. Malama I Ka `Aina: Fostering the Culture-Science connection

    NASA Astrophysics Data System (ADS)

    Bruno, B.; Chinn, P.

    2005-12-01

    The Malama I Ka `Aina Project (Caring for the land, or sustainability) aims to improve and expand the education of Hawai`i's children by developing and disseminating standards-based, culturally relevant science curricular materials based on an understanding and appreciation of the ways in which traditional Hawaiians interacted with their environment for sustainability. Key concepts include the role of water and the ahupua`a (traditional Hawaiian system of land management), and a culture-based sense of place that includes knowledge of and connection to the land. Elementary, middle, high school and University of Hawai`i teachers work together to develop and implement curricula that are especially relevant to a particular school's science program and issues, e.g., invasive species, students, community and/or geographical location. Participants (typically a mix of teachers, education majors and science majors) enroll in Malama I Ka `Aina, a three-credit course offered through the University of Hawai`i`s Dept. of Curriculum Studies and applicable toward a Bachelor's or Master's degree. This course (team taught by scientists, cultural experts and educational professionals) enables participants to: (1) Study Hawai`i`s unique geology, geography and environmental issues in the context of Hawaiian culture and post Western contact; (2) Use course knowledge to develop, teach and assess Hawaii-oriented, project-based, inquiry activities that address the Hawaii Science Content Standards; (3) Gain an appreciation for the scientific method, and the curiosity that drives science (4) Use educational technology such as PowerPoint, graphing packages and web authoring software to develop electronic resources for educational activities. A sample of the lessons developed by course participants can be found on http://malama.hawaii.edu/schools/index2.html. This project is based at the University of Hawai`i College of Education and funded by an award to P. Chinn by the US Department of

  7. Fast wave current drive on DIII-D

    SciTech Connect

    deGrassie, J.S.; Petty, C.C.; Pinsker, R.I.

    1995-07-01

    The physics of electron heating and current drive with the fast magnetosonic wave has been demonstrated on DIII-D, in reasonable agreement with theoretical modeling. A recently completed upgrade to the fast wave capability should allow full noninductive current drive in steady state advanced confinement discharges and provide some current density profile control for the Advanced Tokamak Program. DIII-D now has three four-strap fast wave antennas and three transmitters, each with nominally 2 MW of generator power. Extensive experiments have been conducted with the first system, at 60 MHz, while the two newer systems have come into operation within the past year. The newer systems are configured for 60 to 120 MHz. The measured FWCD efficiency is found to increase linearly with electron temperature as {gamma} = 0.4 {times} 10{sup 18} T{sub eo} (keV) [A/m{sup 2}W], measured up to central electron temperature over 5 keV. A newly developed technique for determining the internal noninductive current density profile gives efficiencies in agreement with this scaling and profiles consistent with theoretical predictions. Full noninductive current drive at 170 kA was achieved in a discharge prepared by rampdown of the Ohmic current. Modulation of microwave reflectometry signals at the fast wave frequency is being used to investigate fast wave propagation and damping. Additionally, rf pick-up probes on the internal boundary of the vessel provide a comparison with ray tracing codes, with dear evidence for a toroidally directed wave with antenna phasing set for current drive. There is some experimental evidence for fast wave absorption by energetic beam ions at high cyclotron harmonic resonances.

  8. Validation of GPM Ka-Radar Algorithm Using a Ground-based Ka-Radar System

    NASA Astrophysics Data System (ADS)

    Nakamura, Kenji; Kaneko, Yuki; Nakagawa, Katsuhiro; Furukawa, Kinji; Suzuki, Kenji

    2016-04-01

    GPM led by the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration of US (NASA) aims to observe global precipitation. The core satellite is equipped with a microwave radiometer (GMI) and a dual-frequency radar (DPR) which is the first spaceborne Ku/Ka-band dual-wavelength radar dedicated for precipitation measurement. In the DPR algorithm, measured radar reflectivity is converted to effective radar reflectivity by estimating the rain attenuation. Here, the scattering/attenuation characteristics of Ka-band radiowaves are crucial, particularly for wet snow. A melting layer observation using a dual Ka-band radar system developed by JAXA was conducted along the slope of Mt. Zao in Yamagata Prefecture, Japan. The dual Ka-band radar system consists of two nearly identical Ka-band FM-CW radars, and the precipitation systems between two radars were observed in opposite directions. From this experiment, equivalent radar reflectivity (Ze) and specific attenuation (k) were obtained. The experiments were conducted for two winter seasons. During the data analyses, it was found that k estimate easily fluctuates because the estimate is based on double difference calculation. With much temporal and spatial averaging, k-Ze relationship was obtained for melting layers. One of the results is that the height of the peak of k seems slightly higher than that of Ze. The results are compared with in-situ precipitation particle measurements.

  9. High-power Ka-band amplifier

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1993-01-01

    Development of a high-power tube suitable to power a Ka-band (34.5-GHz) antenna transmitter located at the Goldstone, California, tracking station is continuing. The University of Maryland Laboratory for Plasma Research and JPL are conducting a joint effort to test the feasibility of phase locking a second-harmonic gyrotron both by direct injection at the output cavity and by using a priming cavity to bunch the electrons in the beam. This article describes several design options and the results of computer simulation testing.

  10. Direct drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1998-03-10

    A positive-drive field actuator motor is described which includes a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 62 figs.

  11. Direct drive field actuator motors

    DOEpatents

    Grahn, Allen R.

    1998-01-01

    A positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  12. pKa at Quartz/Electrolyte Interfaces.

    PubMed

    Pfeiffer-Laplaud, Morgane; Gaigeot, Marie-Pierre; Sulpizi, Marialore

    2016-08-18

    Acidity of silanol sites at the crystalline quartz/aqueous electrolyte (NaCl, NaI, KCl) interfaces are calculated from ab initio molecular dynamics simulations. pKa's are found to follow a combination of the cationic and anionic Hofmeister series in the order pKa(neat solution) < pKa(NaCl) < pKa(NaI) < pKa(KCl), in agreement with experimental measurements. Rationalization of this ranking is achieved in terms of the microscopic local solvation of the protonated silanols and their conjugated bases, the silanolates SiO(-). The change in the pKa is the result of both water destructuring by alkali halides, as well as of the specific cation/SiO(-) interaction, depending on the electrolyte. Molecular modeling at the atomistic level is required to achieve such comprehension, with ab initio molecular dynamics being able to model complex inhomogeneous charged interfaces and the associated interfacial chemical reactivity. PMID:27483195

  13. p Ka calculation of poliprotic acid: histamine

    NASA Astrophysics Data System (ADS)

    De Abreu, Heitor A.; De Almeida, Wagner B.; Duarte, Hélio A.

    2004-01-01

    Various theoretical studies have been reported addressing the performance of solvation models available to estimate p Ka values. However, no attention has been paid so far to the role played by the electronic, thermal and solvation energy individual contributions to the Gibbs free energy of the deprotonation process. In this work, we decompose the total Gibbs free energy into three distinct terms and then evaluate the dependence of each contribution on the level of theory employed for its determination using different levels of theory. The three possible p Kas of histamine have been estimated and compared with available experimental data. We found that the electronic energy term is sensitive to the level of theory and basis set, and, therefore, could be also a source of error in the theoretical calculation of p Kas.

  14. Co-axial Ka-band Free Electron Maser Using Two-dimensional Feedback

    SciTech Connect

    Phelps, A. D. R.; Konoplev, I. V.; McGrane, P.; Cross, A. W.; He, W.; Whyte, C. G.; Ronald, K.; Thumm, M. K.; Ginzburg, N. S.; Peskov, N. Yu.; Sergeev, A. S.

    2006-01-03

    The first successful experimental studies of microwave radiation from a co-axial Free-Electron Maser (FEM) based on two-dimensional (2D) distributed feedback have been recently conducted. This paper contains a description of the experimental set-up and the results obtained. The high-power pulsed power supply and high-current accelerator (HCA) developed and used to drive the FEM are discussed. The results of the experimental study of the FEM operating in the Ka frequency band are presented and compared with theoretical predictions.

  15. Dichroic Filter for Separating W-Band and Ka-Band

    NASA Technical Reports Server (NTRS)

    Epp, Larry W.; Durden, Stephen L.; Jamnejad, Vahraz; Long, Ezra M.; Sosnowski, John B.; Higuera, Raymond J.; Chen, Jacqueline C.

    2012-01-01

    The proposed Aerosol/Cloud/Ecosystems (ACEs) mission development would advance cloud profiling radar from that used in CloudSat by adding a 35-GHz (Ka-band) channel to the 94-GHz (W-band) channel used in CloudSat. In order to illuminate a single antenna, and use CloudSat-like quasi-optical transmission lines, a spatial diplexer is needed to add the Ka-band channel. A dichroic filter separates Ka-band from W-band by employing advances in electrical discharge machining (EDM) and mode-matching analysis techniques developed and validated for designing dichroics for the Deep Space Network (DSN), to develop a preliminary design that both met the requirements of frequency separation and mechanical strength. First, a mechanical prototype was built using an approximately 102-micron-diameter EDM process, and tolerances of the hole dimensions, wall thickness, radius, and dichroic filter thickness measured. The prototype validated the manufacturing needed to design a dichroic filter for a higher-frequency usage than previously used in the DSN. The initial design was based on a Ka-band design, but thicker walls are required for mechanical rigidity than one obtains by simply scaling the Ka-band dichroic filter. The resulting trade of hole dimensions for mechanical rigidity (wall thickness) required electrical redesign of the hole dimensions. Updates to existing codes in the linear solver decreased the analysis time using mode-matching, enabling the electrical design to be realized quickly. This work is applicable to missions and instruments that seek to extend W-band cloud profiling measurements to other frequencies. By demonstrating a dichroic filter that passes W-band, but reflects a lower frequency, this opens up the development of instruments that both compare to and enhance CloudSat.

  16. DARHT 2 kA Cathode Development

    SciTech Connect

    Henestroza, E.; Houck, T.; Kwan, J.W.; Leitner, M.; Miram, G.; Prichard, B.; Roy, P.K.; Waldron, W.; Westenskow, G.; Yu, S.; Bieniosek, F.M.

    2009-03-09

    In the campaign to achieve 2 kA of electron beam current, we have made several changes to the DARHT-II injector during 2006-2007. These changes resulted in a significant increase in the beam current, achieving the 2 kA milestone. Until recently (before 2007), the maximum beam current that was produced from the 6.5-inch diameter (612M) cathode was about 1300 A when the cathode was operating at a maximum temperature of 1140 C. At this temperature level, the heat loss was dominated by radiation which is proportional to temperature to the fourth power. The maximum operating temperature was limited by the damage threshold of the potted filament and the capacity of the filament heater power supply, as well as the shortening of the cathode life time. There were also signs of overheating at other components in the cathode assembly. Thus it was clear that our approach to increase beam current could not be simply trying to run at a higher temperature and the preferred way was to operate with a cathode that has a lower work function. The dispenser cathode initially used was the type 612M made by SpectraMat. According to the manufacturer's bulletin, this cathode should be able to produce more than 10 A/cm{sup 2} of current density (corresponding to 2 kA of total beam current) at our operating conditions. Instead the measured emission (space charge limited) was 6 A/cm{sup 2}. The result was similar even after we had revised the activation and handling procedures to adhere more closely to the recommend steps (taking longer time and nonstop to do the out-gassing). Vacuum was a major concern in considering the cathode's performance. Although the vacuum gauges at the injector vessel indicated 10{sup -8} Torr, the actual vacuum condition near the cathode in the central region of the vessel, where there might be significant out-gassing from the heater region, was never determined. Poor vacuum at the surface of the cathode degraded the emission (by raising the work function value). We

  17. Ka-Band Transponder for Deep-Space Radio Science

    NASA Technical Reports Server (NTRS)

    Dennis, Matthew S.; Mysoor, Narayan R.; Folkner, William M.; Mendoza, Ricardo; Venkatesan, Jaikrishna

    2008-01-01

    A one-page document describes a Ka-band transponder being developed for use in deep-space radio science. The transponder receives in the Deep Space Network (DSN) uplink frequency band of 34.2 to 34.7 GHz, transmits in the 31.8- to 32.3 GHz DSN downlink band, and performs regenerative ranging on a DSN standard 4-MHz ranging tone subcarrier phase-modulated onto the uplink carrier signal. A primary consideration in this development is reduction in size, relative to other such transponders. The transponder design is all-analog, chosen to minimize not only the size but also the number of parts and the design time and, thus, the cost. The receiver features two stages of frequency down-conversion. The receiver locks onto the uplink carrier signal. The exciter signal for the transmitter is derived from the same source as that used to generate the first-stage local-oscillator signal. The ranging-tone subcarrier is down-converted along with the carrier to the second intermediate frequency, where the 4-MHz tone is demodulated from the composite signal and fed into a ranging-tone-tracking loop, which regenerates the tone. The regenerated tone is linearly phase-modulated onto the downlink carrier.

  18. Assigning the pKa's of Polyprotic Acids.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Discusses (1) polyproptic acids for which the difference between K-a's is large; (2) the Henderson-Hasselbach equation; (3) polyprotic acids for which the difference between K-a's is small; (4) analysis of microscopic dissociation constants for cysteine; and (5) analysis of pK-a data. (JN)

  19. Dating loess up to 800 ka by thermoluminescence

    SciTech Connect

    Berger, G.W. ); Pillans, B.J. ); Palmer, A.S. )

    1992-05-01

    Thermoluminescence (TL) ages agreeing with expected ages have been obtained for 13 loess samples spanning the age range from 20 to 800 ka. The authors samples are from Alaska and North Island, New Zealand, and are unusual in TL dating studies of loess older than 80-100 ka by having independent age assignments that are generally well constrained, from ages of associated tephra beds. With the polymineral fine-silt-sized (4-11 {mu}m) grains the partial-bleach TL technique yielded expected ages up to about 350 ka, whereas the total-bleach method gave accurate ages in the range 100 to 800 ka. Thus, the much disputed upper age limit of 100-150 ka for the TL dating of loess now appears to be sample and worker dependent, rather than a global property of the TL signals in the TL-dominant feldspars.

  20. Ka-Band Autonomous Formation Flying Sensor

    NASA Technical Reports Server (NTRS)

    Tien, Jeffrey; Purcell, George, Jr.; Srinivasan, Jeffrey; Ciminera, Michael; Srinivasan, Meera; Meehan, Thomas; Young, Lawrence; Aung, MiMi; Amaro, Luis; Chong, Yong; Quirk, Kevin

    2004-01-01

    Ka-band integrated range and bearing-angle formation sensor called the Autonomous Formation Flying (AFF) Sensor has been developed to enable deep-space formation flying of multiple spacecraft. The AFF Sensor concept is similar to that of the Global Positioning System (GPS), but the AFF Sensor would not use the GPS. The AFF Sensor would reside in radio transceivers and signal-processing subsystems aboard the formation-flying spacecraft. A version of the AFF Sensor has been developed for initial application to the two-spacecraft StarLight optical-interferometry mission, and several design investigations have been performed. From the prototype development, it has been concluded that the AFF Sensor can be expected to measure distances and directions with standard deviations of 2 cm and 1 arc minute, respectively, for spacecraft separations ranging up to about 1 km. It has also been concluded that it is necessary to optimize performance of the overall mission through design trade-offs among the performance of the AFF Sensor, the field of view of the AFF Sensor, the designs of the spacecraft and the scientific instruments that they will carry, the spacecraft maneuvers required for formation flying, and the design of a formation-control system.

  1. High power Ka band TWT amplifier

    SciTech Connect

    Golkowski, C.; Ivers, J.D.; Nation, J.A.; Wang, P.; Schachter, L.

    1999-07-01

    Two high power 35 GHz TWT amplifiers driven by a relativistic pencil, 850 kV, 200A electron beam have been assembled and tested. The first had a dielectric slow wave structure and was primarily used to develop diagnostics, and to gain experience in working with high power systems in Ka band. The source of the input power for the amplifier was a magnetron producing a 30 kW, 200ns long pulse of which 10 kW as delivered to the experiment. The 30 cm long dielectric (Teflon) amplifier produced output power levels of about 1 MW with a gain of about 23 dB. These results are consistent with expectations from PIC code simulations for this arrangement. The second amplifier, which is a single stage disk loaded slow wave structure, has been designed. It consists of one hundred uniform cells with two sets of ten tapered calls at the ends to lower the reflection coefficient. The phase advance per cell is {pi}/2. The amplifier passband extends from 28 to 40 GHz. It is designed to increase the output power to about 20 MW. The amplifier is in construction and will be tested in the near future. Details of the design of both systems will be provided and initial results from the new amplifier presented.

  2. History of Larix decidua Mill. (European larch) since 130 ka

    NASA Astrophysics Data System (ADS)

    Wagner, Stefanie; Litt, Thomas; Sánchez-Goñi, Maria-Fernanda; Petit, Rémy J.

    2015-09-01

    Retrospective studies focussing on forest dynamics using fossil and genetic data can provide important keys to prepare forests for the future. In this study we analyse the impact of past climate and anthropogenic changes on Larix decidua Mill. (European larch) populations based on a new range-wide fossil compilation encompassing the last 130 ka and on recently produced genetic data (nuclear, mitochondrial). Results demonstrate that during the last 130 ka L. decidua persisted close to its current distribution range and colonized vast areas outside this range during the first two early Weichselian interstadials (c. 87-109 ka and c. 83-78 ka), reaching a distributional maxima in the north-central European lowlands. Some fossil sites point to notably rapid responses to some abrupt climate events (Dansgaard-Oeschger cycles and Heinrich Events). Combined fossil and genetic data identify at least six MIS 2 refuges and postglacial recolonization pathways. The establishment of extant L. decidua forests dates back to the first two millennia of the Holocene (c. 11.5-9.5 ka) and the onset of anthropogenic impact was inferred since the late Neolithic (c. 6 ka), with major changes occurring since the Bronze Age (c. 4 ka). During the last 300 years human-induced translocations resulted in recent admixture of populations originating from separate refuges. Altogether, the results of this study provide valuable clues for developing sustainable conservation and management strategies targeting ancient genetic lineages and for studying evolutionary issues.

  3. On the development of protein pKa calculation algorithms

    SciTech Connect

    Carstensen, Tommy; Farrell, Damien; Huang, Yong; Baker, Nathan A.; Nielsen, Jens E.

    2011-12-01

    Protein pKa calculation algorithms are typically developed to reproduce experimental pKa values and provide us with a better understanding of the fundamental importance of electrostatics for protein structure and function. However, the approximations and adjustable parameters employed in almost all pKa calculation methods means that there is the risk that pKa calculation algorithms are 'over-fitted' to the available datasets, and that these methods therefore do not model protein physics realistically. We employ simulations of the protein pKa calculation algorithm development process to show that careful optimization procedures and non-biased experimental datasets must be applied to ensure a realistic description of the underlying physical terms. We furthermore investigate the effect of experimental noise and find a significant effect on the pKa calculation algorithm optimization landscape. Finally, we comment on strategies for ensuring the physical realism of protein pKa calculation algorithms and we assess the overall state of the field with a view to predicting future directions of development.

  4. A hemispherically scanning X/Ka band mirror antenna

    NASA Astrophysics Data System (ADS)

    Hollenbeck, Kurt; Kesler, Oren

    1987-02-01

    Texas Instruments, under contract to Naval Surface Weapons Center (NSWC), have delivered the first proof of concept, prototype X and Ka band Mirror Scanning Antenna to the Navy. This antenna is a candidate for the Navy's new generation of ship self defense weapon systems and culminates over two years of work by Texas Instruments' Antenna Department. Several unique operational features are offered by the Mirror Scanning Antenna. These features include full hemispherical scan coverage, simultaneous X and Ka band dual plane monopulse tracking, rapid scan rates, variable scan modes, high Ka band power handling ability, and an integral weather-tight protective radome.

  5. NASA SCaN Overview and Ka-Band Actvities

    NASA Technical Reports Server (NTRS)

    Stegeman, James D.; Midon, Marco Mario; Davarian, Faramaz; Geldzahler, Barry

    2014-01-01

    The Ka- and Broadband Communications Conference is an international forum attended by worldwide experts in the area of Ka-Band Propagation and satellite communications. Since its inception, NASA has taken the initiative of organizing and leading technical sections on RF Propagation and satellite communications, solidifying its worldwide leadership in the aforementioned areas. Consequently, participation in this conference through the contributions described below will maintain NASA leadership in Ka- and above RF Propagation as it relates to enhancing current and future satellite communication systems supporting space exploration.

  6. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  7. Onboard Interferometric SAR Processor for the Ka-Band Radar Interferometer (KaRIn)

    NASA Technical Reports Server (NTRS)

    Esteban-Fernandez, Daniel; Rodriquez, Ernesto; Peral, Eva; Clark, Duane I.; Wu, Xiaoqing

    2011-01-01

    An interferometric synthetic aperture radar (SAR) onboard processor concept and algorithm has been developed for the Ka-band radar interferometer (KaRIn) instrument on the Surface and Ocean Topography (SWOT) mission. This is a mission- critical subsystem that will perform interferometric SAR processing and multi-look averaging over the oceans to decrease the data rate by three orders of magnitude, and therefore enable the downlink of the radar data to the ground. The onboard processor performs demodulation, range compression, coregistration, and re-sampling, and forms nine azimuth squinted beams. For each of them, an interferogram is generated, including common-band spectral filtering to improve correlation, followed by averaging to the final 1 1-km ground resolution pixel. The onboard processor has been prototyped on a custom FPGA-based cPCI board, which will be part of the radar s digital subsystem. The level of complexity of this technology, dictated by the implementation of interferometric SAR processing at high resolution, the extremely tight level of accuracy required, and its implementation on FPGAs are unprecedented at the time of this reporting for an onboard processor for flight applications.

  8. Computing pKa Values with a Mixing Hamiltonian Quantum Mechanical/Molecular Mechanical Approach.

    PubMed

    Liu, Yang; Fan, Xiaoli; Jin, Yingdi; Hu, Xiangqian; Hu, Hao

    2013-09-10

    Accurate computation of the pKa value of a compound in solution is important but challenging. Here, a new mixing quantum mechanical/molecular mechanical (QM/MM) Hamiltonian method is developed to simulate the free-energy change associated with the protonation/deprotonation processes in solution. The mixing Hamiltonian method is designed for efficient quantum mechanical free-energy simulations by alchemically varying the nuclear potential, i.e., the nuclear charge of the transforming nucleus. In pKa calculation, the charge on the proton is varied in fraction between 0 and 1, corresponding to the fully deprotonated and protonated states, respectively. Inspired by the mixing potential QM/MM free energy simulation method developed previously [H. Hu and W. T. Yang, J. Chem. Phys. 2005, 123, 041102], this method succeeds many advantages of a large class of λ-coupled free-energy simulation methods and the linear combination of atomic potential approach. Theory and technique details of this method, along with the calculation results of the pKa of methanol and methanethiol molecules in aqueous solution, are reported. The results show satisfactory agreement with the experimental data.

  9. Metal band drives in spacecraft mechanisms

    NASA Astrophysics Data System (ADS)

    Maus, Daryl

    1993-05-01

    Transmitting and changing the characteristics of force and stroke is a requirement in nearly all mechanisms. Examples include changing linear to rotary motion, providing a 90 deg change in direction, and amplifying stroke or force. Requirements for size, weight, efficiency and reliability create unique problems in spacecraft mechanisms. Flexible metal band and cam drive systems provide powerful solutions to these problems. Band drives, rack and pinion gears, and bell cranks are compared for effectiveness. Band drive issues are discussed including materials, bend radius, fabrication, attachment and reliability. Numerous mechanisms are shown which illustrate practical applications of band drives.

  10. Metal band drives in spacecraft mechanisms

    NASA Technical Reports Server (NTRS)

    Maus, Daryl

    1993-01-01

    Transmitting and changing the characteristics of force and stroke is a requirement in nearly all mechanisms. Examples include changing linear to rotary motion, providing a 90 deg change in direction, and amplifying stroke or force. Requirements for size, weight, efficiency and reliability create unique problems in spacecraft mechanisms. Flexible metal band and cam drive systems provide powerful solutions to these problems. Band drives, rack and pinion gears, and bell cranks are compared for effectiveness. Band drive issues are discussed including materials, bend radius, fabrication, attachment and reliability. Numerous mechanisms are shown which illustrate practical applications of band drives.

  11. Mars Telecommunications Orbiter Ka-band system design and operations

    NASA Technical Reports Server (NTRS)

    Noreen, Gary; Komarek, Tomas; Diehl, Roger; Shambayati, Shervin; Breidenthal, Julian; Lopez, Saturnino; Jordan, Frank

    2003-01-01

    NASA's Mars Telecommunications Orbiter (MTO) will relay broadband communications from landers, rovers and spacecraft in the vicinity of Mars to Earth. This paper describes the MTO communications system and how the MTO Ka-band system will be operated.

  12. A 20-ka climate record from Central Himalayan loess deposits

    NASA Astrophysics Data System (ADS)

    Pant, R. K.; Basavaiah, N.; Juyal, N.; Saini, N. K.; Yadava, M. G.; Appel, E.; Singhvi, A. K.

    2005-07-01

    The southwest monsoon that dominated Central Himalaya has preserved loessic silt deposits preserved in patches that are proximal to periglacial areas. The occurrence of such silts suggests contemporary prevalence of cold and dry northwesterly winds. Field stratigraphy, geochemistry, mineral magnetism, infrared stimulated luminescence (IRSL) and radiocarbon dating has enabled reconstruction of an event chronology during the past 20 ka. Three events of loess accretion could be identified. The first two events of loess deposition occurred betweem 20 and 9 ka and were separated by a phase of moderate weathering. Pedogenesis at the end of this event gave rise to a well-developed soil that was bracketed around 9 to > 4 ka. This was followed by the third phase of loess accretion that occurred around 4 to > 1 ka. Episodes of loess deposition and soil formation are interpreted in terms of changes in the strength of the Indian southwest monsoon. Copyright

  13. A comparative study of RADAR Ka-band backscatter

    NASA Astrophysics Data System (ADS)

    Mapelli, D.; Pierdicca, N.; Guerriero, L.; Ferrazzoli, Paolo; Calleja, Eduardo; Rommen, B.; Giudici, D.; Monti Guarnieri, A.

    2014-10-01

    Ka-band RADAR frequency range has not yet been used for Synthetic Aperture Radar (SAR) from space so far, although this technology may lead to important applications for the next generation of SAR space sensors. Therefore, feasibility studies regarding a Ka-band SAR instrument have been started [1][2], for the next generation of SAR space sensors. In spite of this, the lack of trusted references on backscatter at Ka-band revealed to be the main limitation for the investigation of the potentialities of this technology. In the framework of the ESA project "Ka-band SAR backscatter analysis in support of future applications", this paper is aimed at the study of wave interaction at Ka-band for a wide range of targets in order to define a set of well calibrated and reliable Ka-band backscatter coefficients for different kinds of targets. We propose several examples of backscatter data resulting from a critical survey of available datasets at Ka-band, focusing on the most interesting cases and addressing both correspondences and differences. The reliability of the results will be assessed via a preliminary comparison with ElectroMagnetic (EM) theoretical models. Furthermore, in support of future technological applications, we have designed a prototypal software acting as a "library" of earth surface radar response. In our intention, the output of the study shall contribute to answer to the need of a trustworthy Ka-Band backscatter reference. It will be of great value for future technological applications, such as support to instrument analysis, design and requirements' definition (e.g.: Signal to Noise Ratio, Noise Equivalent Sigma Zero).

  14. The Mars Observer Ka-band link experiment

    NASA Technical Reports Server (NTRS)

    Rebold, T. A.; Kwok, A.; Wood, G. E.; Butman, S.

    1994-01-01

    The Ka-Band Link Experiment was the first demonstration of a deep-space communications link in the 32- to 35-GHz band (Ka-band). It was carried out using the Mars Observer spacecraft while the spacecraft was in the cruise phase of its mission and using a 34-meter beam-waveguide research and development antenna at the Goldstone complex of the DSN. The DSN has been investigating the performance benefits of a shift from X-band (8.4 GHz) to Ka-band (32 GHz) for deep-space communications. The fourfold increase in frequency is expected to offer a factor of 3 to 10 improvement (5 to 10 dB) in signal strength for a given spacecraft transmitter power and antenna size. Until recently, the expected benefits were based on performance studies, with an eye to implementing such a link, but theory was transformed to reality when a 33.7-GHz Ka-band signal was received from the spacecraft by DSS 13. This article describes the design and implementation of the Ka-Band Link Experiment from the spacecraft to the DSS-13 system, as well as results from the Ka-band telemetry demonstration, ranging demonstration, and long-term tracking experiment. Finally, a preliminary analysis of comparative X- and Ka-band tracking results is included. These results show a 4- to 7-dB advantage for Ka-band using the system at DSS 13, assuming such obstacles as antenna pointing loss and power conversion loss are overcome.

  15. Palaeocirculation across New Zealand during the last glacial maximum at ˜21 ka

    NASA Astrophysics Data System (ADS)

    Lorrey, Andrew M.; Vandergoes, Marcus; Almond, Peter; Renwick, James; Stephens, Tom; Bostock, Helen; Mackintosh, Andrew; Newnham, Rewi; Williams, Paul W.; Ackerley, Duncan; Neil, Helen; Fowler, Anthony M.

    2012-03-01

    What circulation pattern drove Southern Alps glacial advances at ˜21 ka? Late 20th century glacial advances in New Zealand are commonly attributed to a dual precipitation increase and cooler than normal temperatures associated with enhanced westerly flow that occur under synoptic pressure patterns termed 'zonal' regimes (Kidson, 2000). But was the circulation pattern that supported major Southern Alps glacial advances during the global LGM similar to the modern analog? Here, a Regional Climate Regime Classification (RCRC) time slice was used to infer past circulation for New Zealand during the LGM at ˜21 ka. Palaeoclimate information that supported the construction of the ˜21 ka time slice was derived from the NZ-INTIMATE Climate Event Stratigraphy (CES), one new Auckland maar proxy record, and additional low-resolution data sourced from the literature. The terrestrial evidence at ˜21 ka implicates several possibilities for past circulation, depending on how interpretations for some proxies are made. The interpretation considered most tenable for the LGM, based on the agreement between terrestrial evidence, marine reconstructions and palaeoclimate model results is an 'anticyclonic/zonal' circulation regime characterized by increased influences from blocking 'highs' over the South Island during winter and an increase in zonal and trough synoptic types (with southerly to westerly quarter wind flow) during summer. These seasonal circulation traits would have generated lower mean annual temperatures, cooler than normal summer temperatures, and overall lower mean annual precipitation for New Zealand (particularly in the western South Island) at ˜21 ka. The anticyclonic/zonal time slice reconstruction presented in this study has different spatial traits than the late 20th Century and the early Little Ice Age signatures, suggesting more than one type of regional circulation pattern can drive Southern Alps glacial activity. This finding lends support to the hypothesis

  16. Magnetostrictive direct drive motors

    NASA Technical Reports Server (NTRS)

    Naik, Dipak; Dehoff, P. H.

    1992-01-01

    A new rare earth alloy, Terfenol-D, combines low frequency operation and extremely high energy density with high magnetostriction. Its material properties make it suitable as a drive element for actuators requiring high output torque. The high strains, the high forces and the high controllability of Terfenol alloys provide a powerful and challenging basis for new ways to generate motion in actuators. Two prototypes of motors using Terfenol-D rods were developed at NASA Goddard. The basic principles of operation are provided of the motor along with other relevant details. A conceptual design of a torque limiting safety clutch/brake under development is illustrated. Also, preliminary design drawings of a linear actuator using Terfenol-D is shown.

  17. Safe driving for teens

    MedlinePlus

    Driving and teenagers; Teens and safe driving; Automobile safety - teenage drivers ... Make a Commitment to Safety Teens also need to commit to being safe and responsible drivers in order to improve the odds in their favor. Reckless driving ...

  18. Linear Colliders

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akira; Yokoya, Kaoru

    2015-02-01

    An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.

  19. Linear Colliders

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akira; Yokoya, Kaoru

    An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.

  20. Recent Results From The Mars Global Surveyor Ka-Band Link Experiment (MGS/KaBLE-II)

    NASA Technical Reports Server (NTRS)

    Morabito, D.; Butman, S.; Shambayati, S.

    1998-01-01

    The Mars Global Surveyor (MGS) spacecraft, launched on November 7, 1996, carries an experimental space-to-ground telecommunications link at Ka-Band (32 GHz) along with the primary X-band (8.4 GHz) downlink.

  1. Current drive with the second ECR harmonic on T-10

    SciTech Connect

    Alikaev, V.V.; Bagdasarov, A.A.; Borshegovskij, A.A.; Dremin, M.M.; Esipchuk, Y.V.; Gorelov, Y.A.; Ivanov, N.V.; Kislov, A.Y.; Kuznetsova, L.K.; Notkin, G.E.; Pavlov, Y.D.; Razumova, K.A.; Roy, I.N.; Vasin, N.L.; Vershkov, V.A. , Moscow ); Forest, C.B.; Lohr, J.; Luce, T.C.; Harvey, R.W. ); The T-10 Team

    1994-10-15

    The experiments on ECCD on the second harmonic were done. Current about 35 kA was generated. The efficiency of ECCD and its dependencies on plasma parameters were measured. Not all observed phenomena may be explained by the predictions of linear theory.

  2. Linear Collisions

    ERIC Educational Resources Information Center

    Walkiewicz, T. A.; Newby, N. D., Jr.

    1972-01-01

    A discussion of linear collisions between two or three objects is related to a junior-level course in analytical mechanics. The theoretical discussion uses a geometrical approach that treats elastic and inelastic collisions from a unified point of view. Experiments with a linear air track are described. (Author/TS)

  3. Wavelet Analysis of the Periodicity and Correlation of the 420-ka Temperature, Carbon Dioxide, and Methane Time Series from the Vostok Ice Core

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Huang, S.

    2010-12-01

    A good understanding of the history of Earth’s surface temperature and the excursion of atmospheric greenhouse gas composition is of crucial importance in reasoning the course and causes of climate change. However, identifying the variation and correspondence of different climate variables has been a challenging task due to the noisy, complex, and non-linear nature of paleoclimate records. Here we use wavelet technique to revisit the 420-ka temperature, carbon dioxide, and methane records from the ice core of Vostok station in East Antarctica [Petit et al., 1999, Nature, 399, 429] for the periodicity of and the correlation among these three variables. As with many other paleoclimate records, the sampling intervals of the Vostok records are different from variable to variable and from time to time. To allow for the application of continuous Morlet wavelet transform, cross-wavelet transform, and cross-wavelet coherence techniques, all three records were interpolated into 500-year equal interval time series with a cubic polynomial interpolation scheme. All three time series demonstrate the orbital eccentricity oscillation of about 100-ka as the most significant period with a lengthening trend towards the present day. Another periodicity common to all three records is the orbital tilt period of about 41 ka. However, the about 21 ka precession period can only be identified in the methane time series in the Morlet wavelet power spectrum. Our analysis further shows that temperature, CO2, and CH4 are well correlated, whereas the linkage of temperature with CO2 is stranger than that of temperature with CH4 and CO2 with CH4. In pairwise cross-wavelet transform and cross-wavelet coherence diagrams, almost all significant sections show in-phase correlations. Generally, the fluctuations of CO2 and CH4 appear to be either in sync with or slightly led by temperature variation, although there are isolated slots of millennium scales when the temperature - greenhouse gas

  4. Extended Driving Impairs Nocturnal Driving Performances

    PubMed Central

    Sagaspe, Patricia; Taillard, Jacques; Åkerstedt, Torbjorn; Bayon, Virginie; Espié, Stéphane; Chaumet, Guillaume; Bioulac, Bernard; Philip, Pierre

    2008-01-01

    Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3–5am, 1–5am and 9pm–5am) on open highway. Fourteen young healthy men (mean age [±SD] = 23.4 [±1.7] years) participated Inappropriate line crossings (ILC) in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3–5am) driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05) for the intermediate (1–5am) driving session and by 4.0 (CI, 1.7 to 9.4; P<.001) for the long (9pm–5am) driving session. Compared to the reference session (9–10pm), the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001), 15.4 (CI, 4.6 to 51.5; P<.001) and 24.3 (CI, 7.4 to 79.5; P<.001), respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05) and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01). At night, extended driving impairs driving performances and therefore should be limited. PMID:18941525

  5. Variational full wave calculation of fast wave current drive in DIII-D using the ALCYON code

    SciTech Connect

    Becoulet, A.; Moreau, D.

    1992-04-01

    Initial fast wave current drive simulations performed with the ALCYON code for the 60 MHz DIII-D experiment are presented. Two typical shots of the 1991 summer campaign were selected with magnetic field intensities of 1 and 2 teslas respectively. The results for the wave electromagnetic field in the plasma chamber are displayed. They exhibit a strong enrichment of the poloidal mode number m-spectrum which leads to the upshift of the parallel wavenumber, {kappa}{perpendicular}, and to the wave absorption. The m-spectrum is bounded when the local poloidal wavenumber reaches the Alfven wavenumber and the {kappa}{perpendicular} upshifts do not destroy the wave directionality. Linear estimations of the driven current are made. The current density profiles are found to be peaked and we find that about 88 kA can be driven in the 1 tesla/1.7 keV phase with 1.7 MW coupled to the electrons. In the 2 tesla/3.4 keV case, 47 kA are driven with a total power of 1.5 MW, 44% of which are absorbed on the hydrogen minority, through the second harmonic ion cyclotron resonance. The global efficiency is then 0.18 {times} 10{sup 19} A m{sup {minus}2}W{sup {minus}1} if one considers only the effective power going to the electrons.

  6. Coaxial Redundant Drives

    NASA Technical Reports Server (NTRS)

    Brissette, R.

    1983-01-01

    Harmonic drives allow redundancy and high out put torque in small package. If main drive fails, standby drive takes over and produces torque along same axis as main drive. Uses include power units in robot for internal pipeline inspection, manipulators in deep submersible probes or other applications in which redundancy protects against costly failures.

  7. THE CURRENT STAR FORMATION RATE OF K+A GALAXIES

    SciTech Connect

    Nielsen, Danielle M.; Ridgway, Susan E.; De Propris, Roberto; Goto, Tomotsugu

    2012-12-20

    We derive the stacked 1.4 GHz flux from the FIRST survey for 811 K+A galaxies selected from the Sloan Digital Sky Survey Data Release 7. For these objects we find a mean flux density of 56 {+-} 9 {mu}Jy. A similar stack of radio-quiet white dwarfs yields an upper limit of 43 {mu}Jy at a 5{sigma} significance to the flux in blank regions of the sky. This implies an average star formation rate of 1.6 {+-} 0.3 M{sub Sun} yr{sup -1} for K+A galaxies. However, the majority of the signal comes from {approx}4% of K+A fields that have aperture fluxes above the 5{sigma} noise level of the FIRST survey. A stack of the remaining galaxies shows little residual flux consistent with an upper limit on star formation of 1.3 M{sub Sun} yr{sup -1}. Even for a subset of 456 'young' (spectral ages <250 Myr) K+A galaxies, we find that the stacked 1.4 GHz flux is consistent with no current star formation. Our data suggest that the original starburst has been terminated in the majority of K+A galaxies, but that this may represent part of a duty cycle where a fraction of these galaxies may be active at a given moment with dusty starbursts and active galactic nuclei being present.

  8. Solar array drive system

    NASA Technical Reports Server (NTRS)

    Berkopec, F. D.; Sturman, J. C.; Stanhouse, R. W.

    1976-01-01

    A solar array drive system consisting of a solar array drive mechanism and the corresponding solar array drive electronics is being developed. The principal feature of the solar array drive mechanism is its bidirectional capability which enables its use in mechanical redundancy. The solar array drive system is of a widely applicable design. This configuration will be tested to determine its acceptability for generic mission sets. Foremost of the testing to be performed is the testing for extended duration.

  9. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  10. Ka-band MMIC microstrip array for high rate communications

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Raquet, C. A.; Tolleson, J. B.; Sanzgiri, S. M.

    1991-01-01

    In a recent technology assessment of alternative communication systems for the space exploration initiative (SEI), Ka-band (18 to 40 GHz) communication technology was identified to meet the mission requirements of telecommunication, navigation, and information management. Compared to the lower frequency bands, Ka-band antennas offer higher gain and broader bandwidths; thus, they are more suitable for high data rate communications. Over the years, NASA has played an important role in monolithic microwave integrated circuit (MMIC) phased array technology development, and currently, has an ongoing contract with Texas Instrument (TI) to develop a modular Ka-band MMIC microstrip subarray (NAS3-25718). The TI contract emphasizes MMIC integration technology development and stipulates using existing MMIC devices to minimize the array development cost. The objective of this paper is to present array component technologies and integration techniques used to construct the subarray modules.

  11. New directions in linear accelerators

    SciTech Connect

    Jameson, R.A.

    1984-01-01

    Current work on linear particle accelerators is placed in historical and physics contexts, and applications driving the state of the art are discussed. Future needs and the ways they may force development are outlined in terms of exciting R and D challenges presented to today's accelerator designers. 23 references, 7 figures.

  12. A linear magnetic motor and generator

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1980-01-01

    In linear magnetic motor and generator suitable for remote and hostile environments, magnetic forces drive reciprocating shaft along its axis. Actuator shaft is located in center of cylindrical body and may be supported by either contacting or noncontacting bearings. When device operates as bidirectional motor, drive coil selectively adds and subtracts magnetic flux to and from flux paths, producing forces that drive actuator along axis. When actuator is driven by external reciprocating engine, device becomes ac generator.

  13. The Determination of "Apparent" pKa's. Part II: An Experiment Using Very Weak Acids (pKa's > 11.4).

    ERIC Educational Resources Information Center

    Cawley, John J.

    1995-01-01

    Presents an experiment designed to show students that the Henderson-Hasselbalch equation will fail when they use this particular one-half titration technique for acids with large pKa's. Involves determining the apparent pKa for such acids and using that to calculate the true pKa. (JRH)

  14. X-/Ka-band dichroic plate noise temperature reduction

    NASA Technical Reports Server (NTRS)

    Veruttipong, W.; Lee, P.

    1994-01-01

    The X-/Ka-band (8.4 GHz/32.0 GHz) dichroic plate installed as DSS 13 contributes an estimated 3 K to the system noise temperature at 32.0 GHz. Approximately 1 percent of the Ka-band incident field is reflected by the plate into the 300-K environment of the DSS-13 pedestal room. A low-cost, easily implemented method of reducing the noise temperature is presented. Using a curved reflector, the reflected field can be re-focused into an 80-K cold load, reducing the noise temperature contribution of the dichroic plate by about 2 K.

  15. The Ka-Band Propagation Measurements campaign at JPL

    NASA Technical Reports Server (NTRS)

    Chakraborty, D.; Davarian, Faramaz; Stutzman, Warren L.

    1993-01-01

    The objectives of the JPL-managed Propagation Program are discussed, and the types of activities performed to meet these objectives are described. Particular consideration is given to activities of the NASA-sponsored Ka-Band Propagation Measurement campaign, which was established to investigate the applicability of using the Ka-band (20/30 GHz) for satellite telecommunications via ESA's OLYMPUS satellite, which is a precursor to NASA's ACTS. The basic physics involved in this problem are discussed, and the OLYMPUS-program data collected to date are reviewed.

  16. Satellite-borne QPSK Direct Modulator for Ka Band

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Li, Changsheng

    2016-02-01

    Ka band is referred to a microwave band whose frequency range is from 24.6 GHz to 40 GHz, it shares a wide available bandwidth, high frequency reuse rate and strong ability of anti-jamming. This paper presents a novel method to design a modulator for Ka-band satellite communication. Using QPSK to improve the ability of anti-jamming, using direct modulation to reduce the weight, volume and cost of electronic equipment, using sub-harmonic mixer to cut the LO power leakage, excellent modulation results are obtained.

  17. Additional Drive Circuitry for Piezoelectric Screw Motors

    NASA Technical Reports Server (NTRS)

    Smythe, Robert; Palmer, Dean; Gursel, Yekta; Reder, Leonard; Savedra, Raymond

    2004-01-01

    Modules of additional drive circuitry have been developed to enhance the functionality of a family of commercially available positioning motors (Picomotor . or equivalent) that provide linear motion controllable, in principle, to within increments .30 nm. A motor of this type includes a piezoelectric actuator that turns a screw. Unlike traditional piezoelectrically actuated mechanisms, a motor of this type does not rely on the piezoelectric transducer to hold position: the screw does not turn except when the drive signal is applied to the actuator.

  18. Direct-drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1995-07-11

    A high-torque, low speed, positive-drive field actuator motor is disclosed including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 37 figs.

  19. Direct-drive field actuator motors

    DOEpatents

    Grahn, Allen R.

    1995-01-01

    A high-torque, low speed, positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  20. Precision magnetic suspension linear bearing

    NASA Technical Reports Server (NTRS)

    Trumper, David L.; Queen, Michael A.

    1992-01-01

    We have shown the design and analyzed the electromechanics of a linear motor suitable for independently controlling two suspension degrees of freedom. This motor, at least on paper, meets the requirements for driving an X-Y stage of 10 Kg mass with about 4 m/sq sec acceleration, with travel of several hundred millimeters in X and Y, and with reasonable power dissipation. A conceptual design for such a stage is presented. The theoretical feasibility of linear and planar bearings using single or multiple magnetic suspension linear motors is demonstrated.

  1. Multi-Step Ka/Ka Dichroic Plate with Rounded Corners for NASA's 34m Beam Waveguide Antenna

    NASA Technical Reports Server (NTRS)

    Veruttipong, Watt; Khayatian, Behrouz; Hoppe, Daniel; Long, Ezra

    2013-01-01

    A multi-step Ka/Ka dichroic plate Frequency Selective Surface (FSS structure) is designed, manufactured and tested for use in NASA's Deep Space Network (DSN) 34m Beam Waveguide (BWG) antennas. The proposed design allows ease of manufacturing and ability to handle the increased transmit power (reflected off the FSS) of the DSN BWG antennas from 20kW to 100 kW. The dichroic is designed using HFSS and results agree well with measured data considering the manufacturing tolerances that could be achieved on the dichroic.

  2. Computing Linear Mathematical Models Of Aircraft

    NASA Technical Reports Server (NTRS)

    Duke, Eugene L.; Antoniewicz, Robert F.; Krambeer, Keith D.

    1991-01-01

    Derivation and Definition of Linear Aircraft Model (LINEAR) computer program provides user with powerful, and flexible, standard, documented, and verified software tool for linearization of mathematical models of aerodynamics of aircraft. Intended for use in software tool to drive linear analysis of stability and design of control laws for aircraft. Capable of both extracting such linearized engine effects as net thrust, torque, and gyroscopic effects, and including these effects in linear model of system. Designed to provide easy selection of state, control, and observation variables used in particular model. Also provides flexibility of allowing alternate formulations of both state and observation equations. Written in FORTRAN.

  3. Microbial communities involved in Kaşar cheese ripening.

    PubMed

    Aydemir, Oğuz; Harth, Henning; Weckx, Stefan; Dervişoğlu, Muhammet; De Vuyst, Luc

    2015-04-01

    The microbiota of non-starter lactic acid bacteria (NSLAB) and their concomitant community dynamics during cheese ripening were investigated for traditional Turkish Kaşar cheeses made from raw cows' milk. Five batches of 15 Kaşar cheeses produced in different dairy plants located in Kars were analysed during their whole ripening phase up to 180 days. Lactobacilli and lactococci were determined as the prevailing microbial groups. The molecular classification and identification of 594 LAB isolates during Kaşar cheese ripening were performed through (GTG)5-PCR fingerprinting of their genomic DNA followed by verification of the (GTG)5-PCR clusters obtained after numerical analysis through 16S rRNA gene sequencing of representative isolates. Lactobacillus casei (247 isolates, 41.6%), Lactobacillus plantarum (77 isolates, 13.0%), and Pediococcus acidilactici (58 isolates, 9.8%) were the prevailing NSLAB species in all Kaşar cheeses of the different dairy plants investigated throughout cheese ripening. The data of the present study contribute to the inventory of unique cheese varieties to enable the prevention of losses of microbial biodiversity and the selection of starter cultures for controlled cheese manufacturing.

  4. Anatomically modern human in Southeast Asia (Laos) by 46 ka.

    PubMed

    Demeter, Fabrice; Shackelford, Laura L; Bacon, Anne-Marie; Duringer, Philippe; Westaway, Kira; Sayavongkhamdy, Thongsa; Braga, José; Sichanthongtip, Phonephanh; Khamdalavong, Phimmasaeng; Ponche, Jean-Luc; Wang, Hong; Lundstrom, Craig; Patole-Edoumba, Elise; Karpoff, Anne-Marie

    2012-09-01

    Uncertainties surround the timing of modern human emergence and occupation in East and Southeast Asia. Although genetic and archeological data indicate a rapid migration out of Africa and into Southeast Asia by at least 60 ka, mainland Southeast Asia is notable for its absence of fossil evidence for early modern human occupation. Here we report on a modern human cranium from Tam Pa Ling, Laos, which was recovered from a secure stratigraphic context. Radiocarbon and luminescence dating of the surrounding sediments provide a minimum age of 51-46 ka, and direct U-dating of the bone indicates a maximum age of ~63 ka. The cranium has a derived modern human morphology in features of the frontal, occipital, maxillae, and dentition. It is also differentiated from western Eurasian archaic humans in aspects of its temporal, occipital, and dental morphology. In the context of an increasingly documented archaic-modern morphological mosaic among the earliest modern humans in western Eurasia, Tam Pa Ling establishes a definitively modern population in Southeast Asia at ~50 ka cal BP. As such, it provides the earliest skeletal evidence for fully modern humans in mainland Southeast Asia.

  5. Measurement techniques for cryogenic Ka-band microstrip antennas

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Bhasin, K. B.; Gilbert, C.; Metzler, S.; Claspy, P. C.

    1991-01-01

    The measurement of cryogenic antennas poses unique logistical problems since the antenna under test must be embedded in a cooling chamber. A method of measuring the performance of cryogenic microstrip antennas using a closed cycle gas cooled refrigerator in a far field range is described. Antenna patterns showing the performance of gold and superconducting Ka-band microstrip antennas at various temperatures are presented.

  6. Modified Wilkinson Power Dividers For K And Ka Bands

    NASA Technical Reports Server (NTRS)

    Antsos, Dimitrios

    1995-01-01

    Modified configuration for Wilkinson power dividers devised for operating frequencies in K and Ka bands (18 to 27 and 27 to 40 GHz, respectively). Overcomes some difficulties associated with increasing frequency, making possible to design and accurately predict performances of unequal-split power dividers for frequencies above X-band.

  7. Anatomically modern human in Southeast Asia (Laos) by 46 ka

    PubMed Central

    Demeter, Fabrice; Shackelford, Laura L.; Bacon, Anne-Marie; Duringer, Philippe; Westaway, Kira; Sayavongkhamdy, Thongsa; Braga, José; Sichanthongtip, Phonephanh; Khamdalavong, Phimmasaeng; Ponche, Jean-Luc; Wang, Hong; Lundstrom, Craig; Patole-Edoumba, Elise; Karpoff, Anne-Marie

    2012-01-01

    Uncertainties surround the timing of modern human emergence and occupation in East and Southeast Asia. Although genetic and archeological data indicate a rapid migration out of Africa and into Southeast Asia by at least 60 ka, mainland Southeast Asia is notable for its absence of fossil evidence for early modern human occupation. Here we report on a modern human cranium from Tam Pa Ling, Laos, which was recovered from a secure stratigraphic context. Radiocarbon and luminescence dating of the surrounding sediments provide a minimum age of 51–46 ka, and direct U-dating of the bone indicates a maximum age of ∼63 ka. The cranium has a derived modern human morphology in features of the frontal, occipital, maxillae, and dentition. It is also differentiated from western Eurasian archaic humans in aspects of its temporal, occipital, and dental morphology. In the context of an increasingly documented archaic–modern morphological mosaic among the earliest modern humans in western Eurasia, Tam Pa Ling establishes a definitively modern population in Southeast Asia at ∼50 ka cal BP. As such, it provides the earliest skeletal evidence for fully modern humans in mainland Southeast Asia. PMID:22908291

  8. Marine04 Marine radiocarbon age calibration, 26 ? 0 ka BP

    SciTech Connect

    Hughen, K; Baille, M; Bard, E; Beck, J; Bertrand, C; Blackwell, P; Buck, C; Burr, G; Cutler, K; Damon, P; Edwards, R; Fairbanks, R; Friedrich, M; Guilderson, T; Kromer, B; McCormac, F; Manning, S; Bronk-Ramsey, C; Reimer, P; Reimer, R; Remmele, S; Southon, J; Stuiver, M; Talamo, S; Taylor, F; der Plicht, J v; Weyhenmeyer, C

    2004-11-01

    New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration datasets extend an additional 2000 years, from 0-26 ka cal BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically dated tree-ring samples, converted with a box-diffusion model to marine mixed-layer ages, cover the period from 0-10.5 ka cal BP. Beyond 10.5 ka cal BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific {sup 14}C reservoir age information to provide a single global marine mixed-layer calibration from 10.5-26.0 ka cal BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the radiocarbon age to calculate the underlying calibration curve. The marine datasets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring datasets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al.

  9. Driving and neurodegenerative diseases.

    PubMed

    Uc, Ergun Y; Rizzo, Matthew

    2008-09-01

    The proportion of elderly people in the general population is rising, resulting in greater numbers of drivers with neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. These neurodegenerative disorders impair cognition, visual perception, and motor function, leading to reduced driver fitness and greater crash risk. Yet neither medical diagnosis nor age alone is reliable enough to predict driver safety or crashes or to revoke the driving privileges of these individuals. Driving research utilizes tools such as questionnaires about driving habits and history, driving simulators, standardized road tests utilizing instrumented vehicles, and state driving records. Research challenges include outlining the evolution of driving safety, understanding the mechanisms of driving impairment, and developing a reliable and efficient standardized test battery for prediction of driver safety in neurodegenerative disorders. This information will enable healthcare providers to advise their patients with neurodegenerative disorders with more certainty, affect policy, and help develop rehabilitative measures for driving. PMID:18713573

  10. Dementia and driving

    MedlinePlus

    ... has dementia , deciding when they can no longer drive may be difficult. They may react in different ... that the person may not be able to drive safely, such as: Forgetting recent events Mood swings ...

  11. Induction linear accelerators

    NASA Astrophysics Data System (ADS)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typically<10) structures and very large beam pipes. This combination increases the beam breakup limited maximum currents to of order kiloamperes. The micropulse lengths of these machines are measured in 10's of nanoseconds and duty factors as high as 10-4 have been achieved. Until recently the major problem with these machines has been associated with the pulse power drive. Beam currents of kiloamperes and accelerating potentials of megavolts require peak power drives of gigawatts since no energy is stored in the structure. The marriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  12. Gear bearing drive

    NASA Technical Reports Server (NTRS)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  13. Sequential Dependencies in Driving

    ERIC Educational Resources Information Center

    Doshi, Anup; Tran, Cuong; Wilder, Matthew H.; Mozer, Michael C.; Trivedi, Mohan M.

    2012-01-01

    The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find…

  14. Predicting p Ka values from EEM atomic charges.

    PubMed

    Vařeková, Radka Svobodová; Geidl, Stanislav; Ionescu, Crina-Maria; Skřehota, Ondřej; Bouchal, Tomáš; Sehnal, David; Abagyan, Ruben; Koča, Jaroslav

    2013-04-10

    : The acid dissociation constant p Ka is a very important molecular property, and there is a strong interest in the development of reliable and fast methods for p Ka prediction. We have evaluated the p Ka prediction capabilities of QSPR models based on empirical atomic charges calculated by the Electronegativity Equalization Method (EEM). Specifically, we collected 18 EEM parameter sets created for 8 different quantum mechanical (QM) charge calculation schemes. Afterwards, we prepared a training set of 74 substituted phenols. Additionally, for each molecule we generated its dissociated form by removing the phenolic hydrogen. For all the molecules in the training set, we then calculated EEM charges using the 18 parameter sets, and the QM charges using the 8 above mentioned charge calculation schemes. For each type of QM and EEM charges, we created one QSPR model employing charges from the non-dissociated molecules (three descriptor QSPR models), and one QSPR model based on charges from both dissociated and non-dissociated molecules (QSPR models with five descriptors). Afterwards, we calculated the quality criteria and evaluated all the QSPR models obtained. We found that QSPR models employing the EEM charges proved as a good approach for the prediction of p Ka (63% of these models had R2 > 0.9, while the best had R2 = 0.924). As expected, QM QSPR models provided more accurate p Ka predictions than the EEM QSPR models but the differences were not significant. Furthermore, a big advantage of the EEM QSPR models is that their descriptors (i.e., EEM atomic charges) can be calculated markedly faster than the QM charge descriptors. Moreover, we found that the EEM QSPR models are not so strongly influenced by the selection of the charge calculation approach as the QM QSPR models. The robustness of the EEM QSPR models was subsequently confirmed by cross-validation. The applicability of EEM QSPR models for other chemical classes was illustrated by a case study focused on

  15. T-Slide Linear Actuators

    NASA Technical Reports Server (NTRS)

    Vranish, John

    2009-01-01

    T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off

  16. Drill drive mechanism

    DOEpatents

    Dressel, Michael O.

    1979-01-01

    A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfaces of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the differential gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft.

  17. Electromagnetic driving units for complex microrobotic systems

    NASA Astrophysics Data System (ADS)

    Michel, Frank; Ehrfeld, Wolfgang; Berg, Udo; Degen, Reinhard; Schmitz, Felix

    1998-10-01

    Electromagnetic actuators play an important role in macroscopic robotic systems. In combination with motion transformers, like reducing gear units, angular gears or spindle-screw drives, electromagnetic motors in large product lines ensure the rotational or linear motion of robot driving units and grippers while electromagnets drive valves or part conveyors. In this paper micro actuators and miniaturized motion transformers are introduced which allow a similar development in microrobotics. An electromagnetic motor and a planetary gear box, both with a diameter of 1.9 mm, are already commercially available from the cooperation partner of IMM, the company Dr. Fritz Faulhaber GmbH in Schonaich, Germany. In addition, a motor with a diameter of 2.4 mm is in development. The motors successfully drive an angular gear and a belt drive. A linear stage with a motion range of 7 mm and an overall size as small as 5 X 3.5 X 24 mm3 has been realized involving the motor, a stationary spur gear with zero backlash and a spindle-screw drive. By the use of these commercially available elements complex microrobots can be built up cost-efficiently and rapidly. Furthermore, a batch process has been developed to produce the coils of micro actuator arrays using lithographic techniques with SU-8 resin. In applying these components, the modular construction of complex microrobotic systems becomes feasible.

  18. Calibration of the radiocarbon time scale at 37ka BP

    SciTech Connect

    Southon, J.R.; Deino, A.L.; Orsi, G.

    1995-12-01

    Results from radiocarbon and U-Th measurements on corals have provided a radiocarbon calibration beyond the range covered by tree ring series, but the uncertainties in the measurements beyond 20ka BP are very large. We have obtained new calibration data from radiocarbon dates on material associated with the catastrophic Campanian Ignimbrite eruption from the Phlegrean Fields near Naples. The eruption has been well dated by {sup 40}Ar/{sup 39}Ar to 37ka BP. Radiocarbon measurements were carried out on charcoal from a carbonized branch exposed within the ignimbrite tuff on the wall of an active quarry. The sample was split and analyzed at both the Naples and Lawrence Livermore AMS facilities. The offset between the Ar-Ar data and the radiocarbon results (recalculated using the true 5730-year half life for {sup 14}C) is consistent with predictions from paleomagnetic data and carbon cycle modeling.

  19. Ka-band MMIC arrays for ACTS Aero Terminal Experiment

    NASA Technical Reports Server (NTRS)

    Raquet, C.; Zakrajsek, R.; Lee, R.; Turtle, J.

    1992-01-01

    An antenna system consisting of three experimental Ka-band active arrays using GaAs MMIC devices at each radiating element for electronic beam steering and distributed power amplification is presented. The MMIC arrays are to be demonstrated in the ACTS Aeronautical Terminal Experiment, planned for early 1994. The experiment is outlined, with emphasis on a description of the antenna system. Attention is given to the way in which proof-of-concept MMIC arrays featuring three different state-of-the-art approaches to Ka-band MMIC insertion are being incorporated into an experimental aircraft terminal for the demonstration of an aircraft-to-satellite link, providing a basis for follow-on MMIC array development.

  20. A nanoscale linear-to-linear motion converter of graphene.

    PubMed

    Dai, Chunchun; Guo, Zhengrong; Zhang, Hongwei; Chang, Tienchong

    2016-08-14

    Motion conversion plays an irreplaceable role in a variety of machinery. Although many macroscopic motion converters have been widely used, it remains a challenge to convert motion at the nanoscale. Here we propose a nanoscale linear-to-linear motion converter, made of a flake-substrate system of graphene, which can convert the out-of-plane motion of the substrate into the in-plane motion of the flake. The curvature gradient induced van der Waals potential gradient between the flake and the substrate provides the driving force to achieve motion conversion. The proposed motion converter may have general implications for the design of nanomachinery and nanosensors.

  1. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  2. Measurement techniques for cryogenic Ka-band microstrip antennas

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Bhasin, Kul B.; Gilbert, C.; Metzler, S.; Claspy, P. C.

    1992-01-01

    The measurement of cryogenic antennas poses unique logistical problems since the antenna under test must be embedded in the cooling chamber. A method for measuring the performance of cryogenic microstrip antennas using a closed cycle gas-cooled refrigerator in a far field range is described. Antenna patterns showing the performance of gold and superconducting Ka-band microstrip antennas at various temperatures are presented.

  3. X/Ka Celestial Frame Improvements: Vision to Reality

    NASA Technical Reports Server (NTRS)

    Jacobs, C. S.; Bagri, D. S.; Britcliffe, M. J.; Clark, J. E.; Franco, M. M.; Garcia-Miro, C.; Goodhart, C. E.; Horiuchi, S.; Lowe, S. T.; Moll, V. E.; Navarro, R.; Rogstad, S. P.; Proctor, R. C.; Sigman, E. H.; Skjerve, L. J.; Soriano, M. A.; Sovers, O. J.; Tucker, B. C.; Wang, D.; White, L. A.

    2010-01-01

    In order to extend the International Celestial Reference Frame from its S/X-band (2.3/8.4 GHz) basis to a complementary frame at X/Ka-band (8.4/32 GHz), we began in mid-2005 an ongoing series of X/Ka observations using NASA s Deep Space Network (DSN) radio telescopes. Over the course of 47 sessions, we have detected 351 extra-galactic radio sources covering the full 24 hours of right ascension and declinations down to -45 degrees. Angular source position accuracy is at the part-per-billion level. We developed an error budget which shows that the main errors arise from limited sensitivity, mismodeling of the troposphere, uncalibrated instrumental effects, and the lack of a southern baseline. Recent work has improved sensitivity by improving pointing calibrations and by increasing the data rate four-fold. Troposphere calibration has been demonstrated at the mm-level. Construction of instrumental phase calibrators and new digital baseband filtering electronics began in recent months. We will discuss the expected effect of these improvements on the X/Ka frame.

  4. Rain Fade Compensation Alternatives for Ka Band Communication Satellites

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.

    1997-01-01

    Future satellite communications systems operating in Ka-band frequency band are subject to degradation produced by the troposphere which is much more severe than those found at lower frequency bands. These impairments include signal absorption by rain, clouds and gases, and amplitude scintillation's arising from refractive index irregularities. For example, rain attenuation at 20 GHz is almost three times that at 11 GHz. Although some of these impairments can be overcome by oversizing the ground station antennas and high power amplifiers, the current trend is using small (less than 20 inches apertures), low-cost ground stations (less than $1000) that can be easily deployed at user premises. As a consequence, most Ka-band systems are expected to employ different forms of fade mitigation that can be implemented relatively easily and at modest cost. The rain fade mitigation approaches are defined by three types of Ka-band communications systems - a low service rate (less than 1.5 Mb/s), a moderate service rate (1.5 to 6 Mb/s) system and a high service rate (greater than 43 Mb/s) system. The ACTS VSAT network, which includes an adaptive rain fade technique, is an example of a moderate service rate.

  5. Linear Clouds

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03667 Linear Clouds

    These clouds are located near the edge of the south polar region. The cloud tops are the puffy white features in the bottom half of the image.

    Image information: VIS instrument. Latitude -80.1N, Longitude 52.1E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. Universal power transistor base drive control unit

    DOEpatents

    Gale, Allan R.; Gritter, David J.

    1988-01-01

    A saturation condition regulator system for a power transistor which achieves the regulation objectives of a Baker clamp but without dumping excess base drive current into the transistor output circuit. The base drive current of the transistor is sensed and used through an active feedback circuit to produce an error signal which modulates the base drive current through a linearly operating FET. The collector base voltage of the power transistor is independently monitored to develop a second error signal which is also used to regulate base drive current. The current-sensitive circuit operates as a limiter. In addition, a fail-safe timing circuit is disclosed which automatically resets to a turn OFF condition in the event the transistor does not turn ON within a predetermined time after the input signal transition.

  7. Universal power transistor base drive control unit

    DOEpatents

    Gale, A.R.; Gritter, D.J.

    1988-06-07

    A saturation condition regulator system for a power transistor is disclosed which achieves the regulation objectives of a Baker clamp but without dumping excess base drive current into the transistor output circuit. The base drive current of the transistor is sensed and used through an active feedback circuit to produce an error signal which modulates the base drive current through a linearly operating FET. The collector base voltage of the power transistor is independently monitored to develop a second error signal which is also used to regulate base drive current. The current-sensitive circuit operates as a limiter. In addition, a fail-safe timing circuit is disclosed which automatically resets to a turn OFF condition in the event the transistor does not turn ON within a predetermined time after the input signal transition. 2 figs.

  8. Lectures on magnetohydrodynamical drives

    NASA Astrophysics Data System (ADS)

    Loigom, Villem

    The paper deals with nonconventional types of electrical machines and drives - magnetohydrodynamical (MHD) machines and drives. In cardinal it is based on the research conducted with participation of the author in Tallinn Technical University at the Institute of Electrical Drives and Power Electronics, where the use of magnetohydrodynamical motors and drives in the metallurgical and casting industries have been studied for a long time. Major research interests include the qualities and applications of the induction MHD-drives for set in the motion (pumping, turning, dosing, mixing, etc.) non-ferrous molten metals like Al, Mg, Sn, Pb, Na, K, and their alloys. The first part of the paper describes induction MHD motors and their electrohydraulical qualities. In the second part energy conversion problems are described. Also, on the basis of the analogy between electromechanical and electrohydraulical phenomenas, static and dynamic qualities of MHD drives with induction MHD machines are discussed.

  9. Relativistic-Klystron two-beam accelerator as a power source for future linear colliders

    SciTech Connect

    Lidia, S. M.; Anderson, D. E.; Eylon, S.; Henestroza, E.; Vanecek, D. L.; Yu, S. S.; Houck, T. L.; Westenskow, G. A.

    1999-05-07

    The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2-kA, 1-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1% energy variation), and a normalized edge emittance of less than 300 pi-mm-mr. The prototype accelerator will be used to study, physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented.

  10. Relativistic-Klystron two-beam accelerator as a power source for future linear colliders

    SciTech Connect

    Lidia, S.M.; Anderson, D.E.; Eylon, S.; Henestroza, E.; Vanecek, D.L.; Yu, S.S.; Westenskow, G.A.

    1999-05-01

    The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2-kA, 1-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1{percent} energy variation), and a normalized edge emittance of less than 300 pi-mm-mr. The prototype accelerator will be used to study, physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented. {copyright} {ital 1999 American Institute of Physics.}

  11. Pulse generators based on air-insulated linear-transformer-driver stages

    NASA Astrophysics Data System (ADS)

    Kovalchuk, B. M.; Kharlov, A. V.; Kumpyak, E. V.; Zherlitsyn, A. A.

    2013-05-01

    In this paper we present the design and test results of pulse generators based on air-insulated linear-transformer-driver stages that drive a vacuum transmission line. A custom designed unit, referred to as a capacitor block, was developed for use as a main structural element of the transformer stages. It incorporates two capacitors GA 35426 (40 nF, 100 kV) and a multichannel multigap gas switch. Two types of stages were developed: (1) stage LTD-20 with four modules in parallel and five capacitor blocks in each module (in tests of this stage current amplitude up to 850 kA with ˜140ns rise time was obtained on a 0.05Ω load at 100 kV charging voltage); (2) stage LTD-4 with two modules in parallel and two capacitor blocks in each module. Several installations were built on the base of these stages, including a linear transformer, consisting of two identical LTD-20 stages in series, and a high power electron accelerator on the base of LTD-4 stages. The design, tests results, and main problems are presented and discussed in this paper for these installations.

  12. Superluminal warp drive

    NASA Astrophysics Data System (ADS)

    González-Díaz, Pedro F.

    2007-09-01

    In this Letter we consider a warp drive spacetime resulting from that suggested by Alcubierre when the spaceship can only travel faster than light. Restricting to the two dimensions that retains most of the physics, we derive the thermodynamic properties of the warp drive and show that the temperature of the spaceship rises up as its apparent velocity increases. We also find that the warp drive spacetime can be exhibited in a manifestly cosmological form.

  13. Dual excitation multiphase electrostatic drive

    SciTech Connect

    Niino, Toshiki; Higuchi, Toshiro |; Egawa, Saku

    1995-12-31

    A novel electrostatic drive technology named Dual Excitation Multiphase Electrostatic Drive (DEMED) was presented. A basic DEMED consisted of two plastic films in which 3-phase parallel electrodes were embedded and was driven by a 3-phase ac excitation to the electrodes. Static characteristics of DEMED were calculated and tested and the results agreed very well. Three prototype motors of DEMED were fabricated using commercially available technique. The first prototype consisted of a single slider and stator and generated a linear motion with a slider`s motion range of about 5mm. It weighed 7g and generated a power of 1.6W and a thrust force of 4.4N. The second prototype consisted of 50 layer stack of linear motors, summing their outputs. It weighed 3.6kg and generated a propulsive force of 310N being powered with boosted commercial 3-phase electricity. The third prototype consisted of a rotor and a stator in which electrodes were arranged radially and generated rotational motion. The maximum power of 36mW was generated by the prototype weighing only 260mg for its rotor and stator. From the results of the numerical calculation, a practical design methodology for the motor was determined. An optimal design for a motor employing currently available material and fabrication techniques is provided as an example. Analyses predict that force generation over the interfacial area between the slider and stator of this motor would be 3,900N/m{sup 2}.

  14. AltiKa: a Ka-band Altimetry Payload and System for Operational Altimetry during the GMES Period

    PubMed Central

    Vincent, Patrick; Steunou, Nathalie; Caubet, Eric; Phalippou, Laurent; Rey, Laurent; Thouvenot, Eric; Verron, Jacques

    2006-01-01

    This paper describes the Ka-band altimetry payload and system that has been studied for several years by CNES, ALCATEL SPACE and some science laboratories. Altimetry is one of the major elements of the ocean observing system to be made sustainable through the GEOSS (Global Earth Observation System of Systems) and GMES (Global Monitoring of the Environment and Security) programs. A short review of some mission objectives to be fulfilled in terms of mesoscale oceanography in the frame of the GEOSS and GMES programs is performed. To answer the corresponding requirements, the approach consisting in a constellation of nadir altimeter is discussed. A coupled Ka-band altimeter-radiometer payload is then described; technical items are detailed to explain how this payload shall meet the science and operational requirements, and expected performances are displayed. The current status of the payload development and flight perspectives are given.

  15. Diabetes and driving.

    PubMed

    Inkster, B; Frier, B M

    2013-09-01

    The principal safety concern for driving for people treated with insulin or insulin secretagogues is hypoglycaemia, which impairs driving performance. Other complications, such as those causing visual impairment and peripheral neuropathy, are also relevant to medical fitness to drive. Case control studies have suggested that drivers with diabetes pose a modestly increased but acceptable and measurable risk of motor vehicle accidents compared to non-diabetic drivers, but many studies are limited and of poor quality. Factors which have been shown to increase driving risk include previous episodes of severe hypoglycaemia, previous hypoglycaemia while driving, strict glycaemic control (lower HbA1c) and absence of blood glucose monitoring before driving. Impaired awareness of hypoglycaemia may be counteracted by frequent blood glucose testing. The European Union Third directive on driving (2006) has necessitated changes in statutory regulations for driving licences for people with diabetes in all European States, including the UK. Stricter criteria have been introduced for Group 1 vehicle licences while those for Group 2 licences have been relaxed. Insulin-treated drivers can now apply to drive Group 2 vehicles, but in the UK must meet very strict criteria and be assessed by an independent specialist to be issued with a 1-year licence. PMID:23350766

  16. A high-fidelity harmonic drive model.

    SciTech Connect

    Preissner, C.; Royston, T. J.; Shu, D.

    2012-01-01

    In this paper, a new model of the harmonic drive transmission is presented. The purpose of this work is to better understand the transmission hysteresis behavior while constructing a new type of comprehensive harmonic drive model. The four dominant aspects of harmonic drive behavior - nonlinear viscous friction, nonlinear stiffness, hysteresis, and kinematic error - are all included in the model. The harmonic drive is taken to be a black box, and a dynamometer is used to observe the input/output relations of the transmission. This phenomenological approach does not require any specific knowledge of the internal kinematics. In a novel application, the Maxwell resistive-capacitor hysteresis model is applied to the harmonic drive. In this model, sets of linear stiffness elements in series with Coulomb friction elements are arranged in parallel to capture the hysteresis behavior of the transmission. The causal hysteresis model is combined with nonlinear viscous friction and spectral kinematic error models to accurately represent the harmonic drive behavior. Empirical measurements are presented to quantify all four aspects of the transmission behavior. These measurements motivate the formulation of the complete model. Simulation results are then compared to additional measurements of the harmonic drive performance.

  17. Focus drive mechanism for the International Ultraviolet Explorer

    NASA Technical Reports Server (NTRS)

    Schuster, Ludwig E.

    1988-01-01

    The mechanical design of the compact and robust focus drive apparatus developed for the IUE's scientific instrumentation is based on a novel planetary drive that converts the angular increments of a permanent magnet stepping motor into simultaneous linear displacements of three ball screws supporting the secondary mirror. Significant torque margins are thus produced while yielding exceptionally smooth and reliable operation. Attention is given to mechanical drive materials-selection criteria.

  18. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III

    1994-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The linear proof mass actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (mass, upper housing, lower housing, and center support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operating testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  19. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, S. E., III

    1995-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The Linear Proof Mass Actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (Mass, Upper Housing, Lower Housing, and Center Support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operational testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  20. Alcohol policies and impaired driving in the United States: Effects of driving- vs. drinking-oriented policies

    PubMed Central

    Xuan, Ziming; Blanchette, Jason G.; Nelson, Toben F.; Heeren, Timothy C.; Nguyen, Thien H.; Naimi, Timothy S.

    2015-01-01

    Aims To test the hypotheses that stronger policy environments are associated with less impaired driving and that driving-oriented and drinking-oriented policy subgroups are independently associated with impaired driving. Design State-level data on 29 policies in 50 states from 2001–2009 were used as lagged exposures in generalized linear regression models to predict self-reported impaired driving. Setting Fifty United States and Washington, D.C. Participants A total of 1,292,245 adults (≥ 18 years old) biennially from 2002–2010. Measures Alcohol Policy Scale scores representing the alcohol policy environment were created by summing policies weighted by their efficacy and degree of implementation by state-year. Past-30-day alcohol-impaired driving from 2002–2010 was obtained from the Behavioral Risk Factor Surveillance System surveys. Findings Higher Alcohol Policy Scale scores are strongly associated with lower state-level prevalence and individual-level risk of impaired driving. After accounting for driving-oriented policies, drinking-oriented policies had a robust independent association with reduced likelihood of impaired driving. Reduced binge drinking mediates the relationship between drinking-oriented policies and impaired driving, and driving-oriented policies reduce the likelihood of impaired driving among binge drinkers. Conclusions Efforts to reduce alcohol-impaired driving should focus on reducing excessive drinking in addition to preventing driving among those who are impaired. PMID:26925185

  1. Reading Text While Driving

    PubMed Central

    Horrey, William J.; Hoffman, Joshua D.

    2015-01-01

    Objective In this study, we investigated how drivers adapt secondary-task initiation and time-sharing behavior when faced with fluctuating driving demands. Background Reading text while driving is particularly detrimental; however, in real-world driving, drivers actively decide when to perform the task. Method In a test track experiment, participants were free to decide when to read messages while driving along a straight road consisting of an area with increased driving demands (demand zone) followed by an area with low demands. A message was made available shortly before the vehicle entered the demand zone. We manipulated the type of driving demands (baseline, narrow lane, pace clock, combined), message format (no message, paragraph, parsed), and the distance from the demand zone when the message was available (near, far). Results In all conditions, drivers started reading messages (drivers’ first glance to the display) before entering or before leaving the demand zone but tended to wait longer when faced with increased driving demands. While reading messages, drivers looked more or less off road, depending on types of driving demands. Conclusions For task initiation, drivers avoid transitions from low to high demands; however, they are not discouraged when driving demands are already elevated. Drivers adjust time-sharing behavior according to driving demands while performing secondary tasks. Nonetheless, such adjustment may be less effective when total demands are high. Application This study helps us to understand a driver’s role as an active controller in the context of distracted driving and provides insights for developing distraction interventions. PMID:25850162

  2. Proceedings of the international conference on MAGLEV and linear drives

    SciTech Connect

    Not Available

    1986-01-01

    This book presents the papers given at a conference on levitated trains used in rapid transit systems. Topics considered at the conference included urban and regional applications, European systems, magnetically suspended high speed transport systems, the design of induction motors, operational safety consideration, electrodynamics, dynamic interactions between propulsion and suspension systems, power supplies, and superconducting magnets.

  3. Past climate variability between 97 and 7 ka reconstructed from a multi proxy speleothem record from Western Cuba

    NASA Astrophysics Data System (ADS)

    Winterhalder, Sophie; Scholz, Denis; Mangini, Augusto; Spötl, Christoph; Jochum, Klaus Peter; Pajón, Jesús M.

    2016-04-01

    The tropical hydrological cycle plays a key role in regulating global climate, mainly through the export of heat and moisture to higher latitudes, and is highly sensitive to climate change, for instance due to changes in the position of the Intertropical Convergence Zone (ITCZ). Previous work on Caribbean stalagmites suggests a strong connection of precipitation variability to North Atlantic (NA) sea surface temperatures on multidecadal to millenial timescales (Fensterer et al., 2012; Fensterer et al., 2013; Winter et al., 2011). Cold phases in the NA potentially lead to a southward shift of the ITCZ and thus drier conditions in Cuba. On orbital timescales, Cuban stalagmites suggest a relation of speleothem δ18O values with the δ18O value of Caribbean surface waters (Fensterer et al., 2013). Here we present an expansion of the Cuban speleothem record covering the whole last glacial period from the end of MIS5c (97 ka BP) until 7 ka with hiatuses between 93-80 ka, 37-35 ka and 13-10 ka. Stalagmite Cuba medio (CM) has been precisely dated with 60 230Th/U-ages, mainly performed by the MC-ICPMS technique. The δ18O and δ13C records are completed by a continuous, high resolution LA-ICPMS trace element profile. These data allow for the first time to establish a multi-proxy climate reconstruction for the North Western Caribbean at decadal to centennial resolution for this period. The long-term variability of the δ18O values probably reflects rainfall amount in Cuba. The response to some Dansgaard/Oeschger and Heinrich stadials confirms the previously observed correlation between Caribbean and NA climate variability. However, this connection is not clearly imprinted throughout the record. Furthermore, trace elements, such as Mg, do not proof without ambiguity drier conditions in Cuba during NA cold events, such as the Heinrich stadials. This suggests that climate variability in Cuba was more complex during the last 100ka, and that the NA was not the only driving factor

  4. Ocular disease and driving.

    PubMed

    Wood, Joanne M; Black, Alex A

    2016-09-01

    As the driving population ages, the number of drivers with visual impairment resulting from ocular disease will increase given the age-related prevalence of ocular disease. The increase in visual impairment in the driving population has a number of implications for driving outcomes. This review summarises current research regarding the impact of common ocular diseases on driving ability and safety, with particular focus on cataract, glaucoma, age-related macular degeneration, hemianopia and diabetic retinopathy. The evidence considered includes self-reported driving outcomes, driving performance (on-road and simulator-based) and various motor vehicle crash indices. Collectively, this review demonstrates that driving ability and safety are negatively affected by ocular disease; however, further research is needed in this area. Older drivers with ocular disease need to be aware of the negative consequences of their ocular condition and in the case where treatment options are available, encouraged to seek these earlier for optimum driving safety and quality of life benefits. PMID:27156178

  5. Electric vehicles: Driving range

    NASA Astrophysics Data System (ADS)

    Kempton, Willett

    2016-09-01

    For uptake of electric vehicles to increase, consumers' driving-range needs must be fulfilled. Analysis of the driving patterns of personal vehicles in the US now shows that today's electric vehicles can meet all travel needs on almost 90% of days from a single overnight charge.

  6. Piezoelectric drive circuit

    DOEpatents

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  7. Piezoelectric drive circuit

    DOEpatents

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  8. Design of traction drives

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Zaretsky, E. V.

    1985-01-01

    Traction drives are among the simplest of all speed-changing mechanisms. Because of their simplicity and their ability to smoothly and continuously adjust speed, they are excellent choices for many drive system applications. They have been used in industrial service for more than 100 years. Today's traction drives have power capacities which rival the best gear and belt drives due to modern traction fluids and highly fatigue-resistant bearing steels. This report summarizes methods to analyze and size traction drives. Lubrication principles, contact kinematics, stress, fatigue life, and performance prediction methods are presented. The effects of the lubricant's traction characteristics on life and power loss are discussed. An example problem is given which illustrates the effects of spin on power loss. Loading mechanism design and the design of nonlubricated friction wheels and rings are also treated.

  9. Low cost, Ka-band microstrip patch monopulse antenna

    NASA Astrophysics Data System (ADS)

    Jackson, Charles M.; Newman, Jeffrey

    1987-07-01

    A monopulse antenna is a novel concept which combines the theory of an interferometer with the practical application of pulsed radar to obtain the angle and altitude of an object in a single radar pulse; four antennas receive signals that are combined to obtain information about the elevation, azimuth, and distance of an object. This paper describes the design and test of a low-cost Ka-band microstrip antenna. Performance results are examined for 35 GHz (twice the rated frequency), and the antenna patterns are considered.

  10. Ka-Band ARM Zenith Radar (KAZR) Instrument Handbook

    SciTech Connect

    Widener, K; Bharadwaj, N; Johnson, K

    2012-03-06

    The Ka-band ARM zenith radar (KAZR) is a zenith-pointing Doppler cloud radar operating at approximately 35 GHz. The KAZR is an evolutionary follow-on radar to ARM's widely successful millimeter-wavelength cloud radar (MMCR). The main purpose of the KAZR is to provide vertical profiles of clouds by measuring the first three Doppler moments: reflectivity, radial Doppler velocity, and spectra width. At the sites where the dual-polarization measurements are made, the Doppler moments for the cross-polarization channel are also available. In addition to the moments, velocity spectra are also continuously recorded for each range gate.

  11. Design and construction of a Ka-band scatterometer

    NASA Astrophysics Data System (ADS)

    Zoll, Michael

    1994-10-01

    This report provides documentation of a Ka-band scatterometer designed and constructed for the Corps of Engineers Waterways Experiment Station. The system is designed to work in conjunction with a Hewlett-Packard 8510 network analyzer to provide fully polarimetric measurements of back-scatter from terrain. It operates over a 2-GHz bandwidth and can be operated in a monostatic, quasimonostatic, or bistatic configuration. The design, theory of operation, and characteristics are provided as a means to assist the operator or to provide information to others wishing to construct their own.

  12. Acceptance of drinking and driving and alcohol-involved driving crashes in California

    PubMed Central

    Karriker-Jaffe, Katherine J.; Ragland, David R.; Satariano, William A.; Kelley-Baker, Tara; Lacey, John H.

    2016-01-01

    Background Alcohol-impaired driving accounts for substantial proportion of traffic-related fatalities in the U.S. Risk perceptions for drinking and driving have been associated with various measures of drinking and driving behavior. In an effort to understand how to intervene and to better understand how risk perceptions may be shaped, this study explored whether an objective environmental-level measure (proportion of alcohol-involved driving crashes in one's residential city) were related to individual-level perceptions and behavior. Methods Using data from a 2012 cross-sectional roadside survey of 1,147 weekend nighttime drivers in California, individual-level self-reported acceptance of drinking and driving and past-year drinking and driving were merged with traffic crash data using respondent ZIP codes. Population average logistic regression modeling was conducted for the odds of acceptance of drinking and driving and self-reported, past-year drinking and driving. Results A non-linear relationship between city-level alcohol-involved traffic crashes and individual-level acceptance of drinking and driving was found. Acceptance of drinking and driving did not mediate the relationship between the proportion of alcohol-involved traffic crashes and self-reported drinking and driving behavior. However, it was directly related to behavior among those most likely to drink outside the home. Discussion The present study surveys a particularly relevant population and is one of few drinking and driving studies to evaluate the relationship between an objective environmental-level crash risk measure and individual-level risk perceptions. In communities with both low and high proportions of alcohol-involved traffic crashes there was low acceptance of drinking and driving. This may mean that in communities with low proportions of crashes, citizens have less permissive norms around drinking and driving, whereas in communities with a high proportion of crashes, the incidence of

  13. COAXIAL CONTROL ROD DRIVE MECHANISM FOR NEUTRONIC REACTORS

    DOEpatents

    Fox, R.J.; Oakes, L.C.

    1959-04-14

    A drive mechanism is presented for the control rod or a nuclear reactor. In this device the control rod is coupled to a drive shaft which extends coaxially through the rotor of an electric motor for relative rotation with respect thereto. A gear reduction mehanism is coupled between the rotor and the drive shaft to convert the rotary motion of the motor into linear motion of the shaft with a comparatively great reduction in speed, thereby providing relatively glow linear movement of the shaft and control rod for control purposes.

  14. The Test Drive

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image taken at NASA's Jet Propulsion Laboratory shows engineers rehearsing the sol 133 (June 8, 2004) drive into 'Endurance' crater by NASA's Mars Exploration Rover Opportunity. Engineers and scientists have recreated the martian surface and slope the rover will encounter using a combination of bare and thinly sand-coated rocks, simulated martian 'blueberries' and a platform tilted at a 25-degree angle. The results of this test convinced engineers that the rover was capable of driving up and down a straight slope before it attempted the actual drive on Mars.

  15. Vision and Driving

    PubMed Central

    Owsley, Cynthia; McGwin, Gerald

    2010-01-01

    Driving is the primary means of personal travel in many countries and is relies heavily on vision for its successful execution. Research over the past few decades has addressed the role of vision in driver safety (motor vehicle collision involvement) and in driver performance (both on-road and using interactive simulators in the laboratory). Here we critically review what is currently known about the role of various aspects of visual function in driving. We also discuss translational research issues on vision screening for licensure and re-licensure and rehabilitation of visually impaired persons who want to drive. PMID:20580907

  16. Drive System Research

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.

    2007-01-01

    An overview of the NASA Glenn Research Center Drive Systems Research will be presented. The primary purpose of this research is to improve performance, reliability, and integrity of aerospace drive systems and space mechanisms. The research is conducted through a combination of in-house, academia, and through contractors. Research is conducted through computer code development and validated through component and system testing. The drive system activity currently has four major thrust areas including: thermal behavior of high speed gearing, health and usage monitoring, advanced components, and space mechanisms.

  17. Polar Direct Drive

    NASA Astrophysics Data System (ADS)

    Skupsky, S.

    2003-10-01

    Direct drive offers the potential of higher target gain on the National Ignition Facility (NIF) than x-ray drive: The initial direct-drive target design had a 1-D gain of 45 and consisted primarily of a pure cryogenic DT shell. Using the expected levels of target and laser nonuniformities for the NIF, two-dimensional (2-D) hydrodynamic simulations predicted target gains around 30.(P.W. McKenty et al.), Phys. Plasmas 8, 2315 (2001). More-recent designs have shown that higher target gains could be obtained by replacing a portion of the DT shell with ``wetted'' CH foam and by using adiabat shaping: (1) Higher-Z material (C) in the foam increases laser absorption by about 40% (from 60% absorption to 85%).(S. Skupsky et al.), in Inertial Fusion Sciences and Applications 2001, edited by K. Tanaka et al. (Elsevier, Paris, 2002), p. 240. (2) Adiabat shaping allows the main portion of the fuel to be placed on a lower adiabat without compromising target stability.(V.N. Goncharov et al.), Phys. Plasmas 10, 1906 (2003). These direct-drive concepts can be tested on the NIF, long before that facility is converted to a direct-drive (spherically symmetric) irradiation configuration. Using the NIF x-ray-drive beam configuration, some of the near-polar beams could be pointed to better illuminate the target's equator. These more-oblique, equatorial beams will have lower absorption and reduced drive efficiency than the polar beams. One strategy to compensate for the difference in polar and equatorial drive is to reduce the irradiation at the poles and employ different pulse shapes to accommodate the time-dependent variations in drive and absorption. This concept of polar direct drive (PDD) has been studied using the 2-D hydrocode DRACO to determine the requirements for achieving ignition and moderate target gain for the NIF. Experiments on the OMEGA laser will examine the effects of oblique irradiation on target drive. Results of simulations for different direct-drive target designs

  18. Ultra Small Aperture Terminal for Ka-Band SATCOM

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto; Reinhart, Richard; Lee, Richard; Simons, Rainee

    1997-01-01

    An ultra small aperture terminal (USAT) at Ka-band frequency has been developed by Lewis Research Center (LeRC) for data rates up to 1.5 Mbps in the transmit mode and 40 Mbps in receive mode. The terminal consists of a 35 cm diameter offset-fed parabolic antenna which is attached to a solid state power amplifier and low noise amplifier. A single down converter is used to convert the Ka-band frequency to 70 MHz intermediate frequency (IF). A variable rate (9.6 Kbps to 10 Mbps) commercial modem with a standard RS-449/RS-232 interface is used to provide point-to-point digital services. The terminal has been demonstrated numerous times using the Advanced Communications Technology Satellite (ACTS) and the 4.5 in Link Evaluation Terminal (LET) in Cleveland. A conceptual design for an advanced terminal has also been developed. This advanced USAT utilizes Microwave Monolithic Integrated Circuit (MMIC) and flat plate array technologies. This terminal will be self contained in a single package which will include a 1 watt solid state amplifier (SSPA), low noise amplifier (LNA) and a modem card located behind the aperture of the array. The advanced USAT will be light weight, transportable, low cost and easy to point to the satellite. This paper will introduce designs for the reflector based and array based USAT's.

  19. K/Ka-band channel characterization for mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Pinck, Deborah S.; Rice, Michael D.

    1995-01-01

    Mobile satellite systems allow truly ubiquitous wireless communications to users anywhere and anytime. NASA's Advanced Communications Technology Satellite (ACTS) provides an ideal space-based platform for the measurement of K/Ka band propagation characteristics in a land mobile satellite application. Field tests conducted in Southern California during the first seven months of 1994 using JPL's ACTS Mobile Terminal (AMT) provided channel characterization data for the K/Ka-band link. A pilot tone was transmitted from a fixed station in Cleveland, Ohio through the satellite and downlinked at 20 GHz in the Southern California spot beam. The AMT was equipped with a narrow beam, high gain antenna which tracked the satellite in azimuth for a fixed elevation angle (46 degrees for this case). The field tests were conducted in three basic environments: clear line-of-sight (LOS) highways, lightly shadowed suburban, and heavily shadowed suburban. Preliminary results of these field tests indicate very little multipath for rural environments and for clear LOS links (as expected with a narrow beam antenna). Deep fades were experienced in shadowed areas, especially those where tree canopies covered the road.

  20. ITIL and Grid services at GridKa

    NASA Astrophysics Data System (ADS)

    Marten, H.; Koenig, T.

    2010-04-01

    The Steinbuch Centre for Computing (SCC) is a new organizational unit of the Karlsruhe Institute of Technology (KIT). Founded in February 2008 as a merger of the previous Institute for Scientific Computing of Forschungszentrum Karlsruhe and the Computing Centre of the Technical University Karlsruhe, SCC provides a broad spectrum of IT services for 8.000 employees and 18.000 students and carries out research and development in key areas of information technology under the same roof. SCC is also known to host the German WLCG [1] Tier-1 centre GridKa. In order to accompany the merging of the two existing computing centres located at a distance of about 10 km and to provide common first class services for science, SCC has selected the IT service management according to the industrial quasi-standard "IT Infrastructure Library (ITIL)" [3] as a strategic element. The paper discusses the implementation of a few ITIL key components from the perspective of a Scientific Computing Centre using examples of Grid services at GridKa.

  1. Axial mass fraction measurements in a 300kA dense plasma focus

    NASA Astrophysics Data System (ADS)

    Caballero Bendixsen, L. S.; Bott-Suzuki, S. C.; Cordaro, S. W.; Krishnan, M.; Chapman, S.; Coleman, P.; Chittenden, J.

    2016-09-01

    The dynamics and characteristics of the plasma sheath during the axial phase in a ˜300 kA, ˜2 kJ dense plasma focus using a static gas load of Ne at 1-4 Torr are reported. The sheath, which is driven axially at a constant velocity ˜105 m/s by the j × B force, is observed using optical imaging, to form an acute angle between the electrodes. This angle becomes more acute (more parallel to the axis) along the rundown. The average sheath thickness nearer the anode is 0.69 ± 0.02 mm and nearer the cathode is 0.95 ± 0.02 mm. The sheath total mass increases from 1 ± 0.02 μg to 6 ± 0.02 μg over the pressure range of 1-4 Torr. However, the mass fraction (defined as the sheath mass/total mass of cold gas between the electrodes) decreases from 7% to 5%. In addition, the steeper the plasma sheath, the more mass is lost from the sheath, which is consistent with radial and axial motion. Experimental results are compared to the Lee code when 100% of the current drives the axial and radial phase.

  2. Drive program documentation

    NASA Technical Reports Server (NTRS)

    Graham, S.

    1979-01-01

    The program description and user's guide for the Downlist Requirement Integrated Verification and Evaluation (DRIVE) program is provided. The program is used to compare existing telemetry downlist files with updated downlist requirements.

  3. Control rod drive

    DOEpatents

    Hawke, Basil C.

    1986-01-01

    A control rod drive uses gravitational forces to insert one or more control rods upwardly into a reactor core from beneath the reactor core under emergency conditions. The preferred control rod drive includes a vertically movable weight and a mechanism operatively associating the weight with the control rod so that downward movement of the weight is translated into upward movement of the control rod. The preferred control rod drive further includes an electric motor for driving the control rods under normal conditions, an electrically actuated clutch which automatically disengages the motor during a power failure and a decelerator for bringing the control rod to a controlled stop when it is inserted under emergency conditions into a reactor core.

  4. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

    2007-02-27

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  5. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

    2006-07-11

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  6. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

    2006-10-10

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  7. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett Lee; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

    2006-09-19

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  8. CONTROL ROD DRIVE

    DOEpatents

    Chapellier, R.A.

    1960-05-24

    BS>A drive mechanism was invented for the control rod of a nuclear reactor. Power is provided by an electric motor and an outside source of fluid pressure is utilized in conjunction with the fluid pressure within the reactor to balance the loadings on the motor. The force exerted on the drive mechanism in the direction of scramming the rod is derived from the reactor fluid pressure so that failure of the outside pressure source will cause prompt scramming of the rod.

  9. Self-driving carsickness.

    PubMed

    Diels, Cyriel; Bos, Jelte E

    2016-03-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and productivity. However, we here show that the envisaged scenarios all lead to an increased risk of motion sickness. As such, the benefits this technology is assumed to bring may not be capitalised on, in particular by those already susceptible to motion sickness. This can negatively affect user acceptance and uptake and, in turn, limit the potential socioeconomic benefits that this emerging technology may provide. Following a discussion on the causes of motion sickness in the context of self-driving cars, we present guidelines to steer the design and development of automated vehicle technologies. The aim is to limit or avoid the impact of motion sickness and ultimately promote the uptake of self-driving cars. Attention is also given to less well known consequences of motion sickness, in particular negative aftereffects such as postural instability, and detrimental effects on task performance and how this may impact the use and design of self-driving cars. We conclude that basic perceptual mechanisms need to be considered in the design process whereby self-driving cars cannot simply be thought of as living rooms, offices, or entertainment venues on wheels.

  10. Dementia and driving.

    PubMed

    O'Neill, D; Neubauer, K; Boyle, M; Gerrard, J; Surmon, D; Wilcock, G K

    1992-04-01

    Many European countries test cars, but not their drivers, as they age. There is evidence to suggest that human factors are more important than vehicular factors as causes of motor crashes. The elderly also are involved in more accidents per distance travelled than middle-aged drivers. As the UK relies on self-certification of health by drivers over the age of 70 years, we examined the driving practices of patients with dementia attending a Memory Clinic. Nearly one-fifth of 329 patients with documented dementia continued to drive after the onset of dementia, and impaired driving ability was noted in two-thirds of these. Their families experienced great difficulty in persuading patients to stop driving, and had to invoke outside help in many cases. Neuropsychological tests did not help to identify those who drove badly while activity of daily living scores were related to driving ability. These findings suggest that many patients with dementia drive in an unsafe fashion after the onset of the illness. The present system of self-certification of health by the elderly for driver-licensing purposes needs to be reassessed.

  11. Self-driving carsickness.

    PubMed

    Diels, Cyriel; Bos, Jelte E

    2016-03-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and productivity. However, we here show that the envisaged scenarios all lead to an increased risk of motion sickness. As such, the benefits this technology is assumed to bring may not be capitalised on, in particular by those already susceptible to motion sickness. This can negatively affect user acceptance and uptake and, in turn, limit the potential socioeconomic benefits that this emerging technology may provide. Following a discussion on the causes of motion sickness in the context of self-driving cars, we present guidelines to steer the design and development of automated vehicle technologies. The aim is to limit or avoid the impact of motion sickness and ultimately promote the uptake of self-driving cars. Attention is also given to less well known consequences of motion sickness, in particular negative aftereffects such as postural instability, and detrimental effects on task performance and how this may impact the use and design of self-driving cars. We conclude that basic perceptual mechanisms need to be considered in the design process whereby self-driving cars cannot simply be thought of as living rooms, offices, or entertainment venues on wheels. PMID:26446454

  12. Hydraulic drive system prevents backlash

    NASA Technical Reports Server (NTRS)

    Acord, J. D.

    1965-01-01

    Hydraulic drive system uses a second drive motor operating at reduced torque. This exerts a relative braking action which eliminates the normal gear train backlash that is intolerable when driving certain heavy loads.

  13. Electron Cyclotron / Bernstein Wave Heating and Current Drive Experiments using Phased-array Antenna in QUEST

    SciTech Connect

    Idei, H.; Zushi, H.; Hanada, K.; Nakamura, K.; Fujisawa, A.; Hasegawa, M.; Yoshida, N.; Watanebe, H.; Tokunaga, K.; Nagashima, Y.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Sakamoto, M.; Ejiri, A.; Takase, Y.; Sakaguchi, M.; Kalinnikova, E.; Ishiguro, M.; Tashima, S.

    2011-12-23

    The phased-array antenna system for Electron Cyclotron/Bernstein Wave Heating and Current Drive experiments has been developed in the QUEST. The antenna was designed to excite a pure O-mode wave in the oblique injection for the O-X-B mode conversion experiments, and its good performances were confirmed at a low power level. The plasma current (<{approx}15 kA) with an aspect ratio of 1.5 was started up and sustained by only RF injection in the low-density operations. The long pulse discharge of 10 kA was also attained for 37 s. The new density window to sustain the plasma current was observed in the high-density plasmas. The single-null divertor configuration with the high plasma current (<{approx}25 kA) was attained in the 17 s plasma sustainment.

  14. Evaluating North America Paleoclimate Simulations using Simulated and Observed Paleovegetation Data for 6 ka and 21 ka

    NASA Astrophysics Data System (ADS)

    Shafer, S. L.; Bartlein, P. J.; Thompson, R. S.; Anderson, K.; Izumi, K.; Strickland, L. E.; Pelltier, R.

    2013-12-01

    An important use of paleoclimate data is to evaluate climate models that simulate future climate. We used paleoclimate simulations from the Paleoclimate Modelling Intercomparison Project phase 3 (PMIP3) and Coupled Model Intercomparison Project phase 5 (CMIP5) database to evaluate simulated and observed vegetation agreement for 6 ka and 21 ka. The paleoclimate simulations were downscaled to a 10-km grid of North America following the PMIP3 vegetation simulation protocol. The downscaled climate data were used with BIOME4, an equilibrium vegetation model, to simulate paleovegetation for each time period. The simulated paleovegetation was compared with observed paleovegetation data from the BIOME 6000 (ver. 4.2) dataset and the U.S. Geological Survey/NOAA North American Packrat Midden Database (ver. 3). We evaluated the magnitude and spatial patterns of agreement and disagreement of the observed and simulated paleovegetation. The results were analyzed for individual climate model simulations and paleovegetation types. Some simulated paleovegetation types (e.g., needleleaf evergreen forest) showed good agreement with observed paleovegetation data while other simulated paleovegetation types (e.g., open conifer woodland) showed relatively poor agreement. The analyses provide insights into climate and vegetation model performance and suggest opportunities for improving both model simulations and interpretations of observed paleovegetation data.

  15. TESLA cavity driving with FPGA controller

    NASA Astrophysics Data System (ADS)

    Czarski, Tomasz; Pozniak, Krzysztof; Romaniuk, Ryszard; Simrock, Stefan

    2005-09-01

    The digital control of the TESLA (TeV-Energy Superconducting Linear Accelerator) resonator is presented. The laboratory setup of the CHECHIA cavity in DESY-Hamburg has been driven by the FPGA (Field Programmable Gate Array) technology system. This experiment focused attention to the general recognition of the cavity features and projected control methods. The electrical model of the resonator is taken as a consideration origin. The calibration of the signal channel is considered as a key preparation for an efficient cavity driving. The identification of the resonator parameters is confirmed as a proper approach for the required performance: driving on resonance during filling and field stabilization during flattop time with reasonable power consumption. The feed-forward and feedback modes were applied successfully for the CHECHIA cavity driving. Representative results of experiments are presented for different levels of the cavity field gradient.

  16. Ka-Band Multibeam Aperture Phased Array Being Developed

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.; Kacpura, Thomas J.

    2004-01-01

    Phased-array antenna systems offer many advantages to low-Earth-orbiting satellite systems. Their large scan angles and multibeam capabilities allow for vibration-free, rapid beam scanning and graceful degradation operation for high rate downlink of data to users on the ground. Technology advancements continue to reduce the power, weight, and cost of these systems to make phased arrays a competitive alternative in comparison to the gimbled reflector system commonly used in science missions. One effort to reduce the cost of phased arrays is the development of a Ka-band multibeam aperture (MBA) phased array by Boeing Corporation under a contract jointly by the NASA Glenn Research Center and the Office of Naval Research. The objective is to develop and demonstrate a space-qualifiable dual-beam Ka-band (26.5-GHz) phased-array antenna. The goals are to advance the state of the art in Ka-band active phased-array antennas and to develop and demonstrate multibeam transmission technology compatible with spacecraft in low Earth orbit to reduce the cost of future missions by retiring certain development risks. The frequency chosen is suitable for space-to-space and space-to-ground communication links. The phased-array antenna has a radiation pattern designed by combining a set of individual radiating elements, optimized with the type of radiating elements used, their positions in space, and the amplitude and phase of the currents feeding the elements. This arrangement produces a directional radiation pattern that is proportional to the number of individual radiating elements. The arrays of interest here can scan the main beam electronically with a computerized algorithm. The antenna is constructed using electronic components with no mechanical parts, and the steering is performed electronically, without any resulting vibration. The speed of the scanning is limited primarily by the control electronics. The radiation performance degrades gracefully if a portion of the elements

  17. Gigahertz resonance characteristics of nanotube linear motor

    NASA Astrophysics Data System (ADS)

    Kang, Jeong-Won; Choi, Young Gyu; Ryu, Gi Han; Won, Chung Sang

    2008-08-01

    We investigated a linear carbon nanotube motor serving as the key building block for nanoscale motion control by using molecular dynamics simulations. This linear nanomotor, is based on the electrostatically telescoping multi-walled carbon-nanotube with ultralow intershell sliding friction, is controlled by the gate potential with the capacitance feedback sensing. The resonant harmonic peaks are induced by the interference between the driving frequencies and its self-frequency. The temperature is very important factor to operate this nanomotor.

  18. GGOPT: an unconstrained non-linear optimizer.

    PubMed

    Bassingthwaighte, J B; Chan, I S; Goldstein, A A; Russak, I B

    1988-01-01

    GGOPT is a derivative-free non-linear optimizer for smooth functions with added noise. If the function values arise from observations or from extensive computations, these errors can be considerable. GGOPT uses an adjustable mesh together with linear least squares to find smoothed values of the function, gradient and Hessian at the center of the mesh. These values drive a descent method that estimates optimal parameters. The smoothed values usually result in increased accuracy.

  19. Mental workload and driving

    PubMed Central

    Paxion, Julie; Galy, Edith; Berthelon, Catherine

    2014-01-01

    The aim of this review is to identify the most representative measures of subjective and objective mental workload in driving, and to understand how the subjective and objective levels of mental workload influence the performance as a function of situation complexity and driving experience, i.e., to verify whether the increase of situation complexity and the lack of experience increase the subjective and physiological levels of mental workload and lead to driving performance impairments. This review will be useful to both researchers designing an experimental study of mental workload and to designers of drivers’ training content. In the first part, we will broach the theoretical approach with two factors of mental workload and performance, i.e., situation complexity and driving experience. Indeed, a low complex situation (e.g., highways), or conversely a high complex situation (e.g., town) can provoke an overload. Additionally, performing the driving tasks implies producing a high effort for novice drivers who have not totally automated the driving activity. In the second part, we will focus on subjective measures of mental workload. A comparison of questionnaires usually used in driving will allow identifying the most appropriate ones as a function of different criteria. Moreover, we will review the empirical studies to verify if the subjective level of mental workload is high in simple and very complex situations, especially for novice drivers compared to the experienced ones. In the third part, we will focus on physiological measures. A comparison of physiological indicators will be realized in order to identify the most correlated to mental workload. An empirical review will also take the effect of situation complexity and experience on these physiological indicators into consideration. Finally, a more nuanced comparison between subjective and physiological measures will be established from the impact on situation complexity and experience. PMID:25520678

  20. Stabilization system of a photoinjector drive laser.

    PubMed

    Le Flanchec, V; Blésès, J P; Striby, S; Laget, J P

    1997-11-20

    In the Etude d'un LaSer Accordable linear accelerator, electron bunches consist of trains of picosecond pulses extracted from a photocathode by a drive laser system. The fluctuations of the mean intensity of pulse trains at the output of the laser system are around 3% rms. A feed-forward stabilization system that reduces these fluctuations to better than 0.7% rms for periods of 5 min is presented. PMID:18264399

  1. Stabilization system of a photoinjector drive laser

    NASA Astrophysics Data System (ADS)

    Le Flanchec, Vincent; Blésès, Jean-Paul; Striby, Serge; Laget, Jean-Paul

    1997-11-01

    In the Etude d un LaSer Accordable linear accelerator, electron bunches consist of trains of picosecond pulses extracted from a photocathode by a drive laser system. The fluctuations of the mean intensity of pulse trains at the output of the laser system are around 3% rms. A feed-forward stabilization system that reduces these fluctuations to better than 0.7% rms for periods of 5 min is presented.

  2. ACTIVE GALACTIC NUCLEI AND THE TRUNCATION OF STAR FORMATION IN K+A GALAXIES

    SciTech Connect

    Brown, Michael J. I.; Palamara, David; Moustakas, John; Caldwell, Nelson; Cool, Richard J.; Zaritsky, Dennis; Dey, Arjun; Jannuzi, Buell T.; Hickox, Ryan C.; Murray, Stephen S.

    2009-09-20

    We have searched for active galactic nuclei (AGNs) in K+A galaxies, using multiwavelength imaging and spectroscopy in the Booetes field of the NOAO Deep Wide-Field Survey. The K+A galaxies, which have had their star formation rapidly truncated, are selected via their strong Balmer absorption lines and weak Halpha emission. Our sample consists of 24 K+A galaxies selected from 6594 0.10 < z < 0.35 galaxies brighter than I = 20 with optical spectroscopy from the AGN and Galaxy Evolution Survey. Two thirds of the K+A galaxies are likely ongoing galaxy mergers, with nearby companion galaxies or tidal tails. Galaxy mergers may be responsible for the truncation of star formation, or we are observing the aftermath of merger triggered starbursts. As expected, the optical colors of K+A galaxies largely fall between blue galaxies with ongoing star formation and red passive galaxies. However, only 1% of the galaxies with colors between the red and blue populations are K+A galaxies, and we conclude that the truncation of star formation in K+A galaxies must have been unusually abrupt ({approx}<100 Myr). We examined the AGN content of K+A galaxies with both optical emission-line ratios (BPT diagrams) and Chandra X-ray imaging. At least half of all K+A galaxies display the optical emission-line ratios of AGNs, and a third of M{sub R} < -22 K+A galaxies host AGNs with X-ray luminosities of {approx}10{sup 42} erg s{sup -1}. The faintest K+A galaxies do not show clear evidence for hosting AGNs, having emission-line ratios consistent with photoionization by massive stars and few X-ray detections. We speculate that two mechanisms may be responsible for the truncation of star formation in K+A galaxies, with AGN feedback only playing a role in M{sub R} {approx}< -20.5 galaxies.

  3. Fundamental limitations on 'warp drive' spacetimes

    NASA Astrophysics Data System (ADS)

    Lobo, Francisco S. N.; Visser, Matt

    2004-12-01

    'Warp drive' spacetimes are useful as 'gedanken-experiments' that force us to confront the foundations of general relativity, and among other things, to precisely formulate the notion of 'superluminal' communication. After carefully formulating the Alcubierre and Natário warp drive spacetimes, and verifying their non-perturbative violation of the classical energy conditions, we consider a more modest question and apply linearized gravity to the weak-field warp drive, testing the energy conditions to first and second orders of the warp-bubble velocity, v. Since we take the warp-bubble velocity to be non-relativistic, v Lt c, we are not primarily interested in the 'superluminal' features of the warp drive. Instead we focus on a secondary feature of the warp drive that has not previously been remarked upon—the warp drive (if it could be built) would be an example of a 'reaction-less drive'. For both the Alcubierre and Natário warp drives we find that the occurrence of significant energy condition violations is not just a high-speed effect, but that the violations persist even at arbitrarily low speeds. A particularly interesting feature of this construction is that it is now meaningful to think of placing a finite mass spaceship at the centre of the warp bubble, and then see how the energy in the warp field compares with the mass energy of the spaceship. There is no hope of doing this in Alcubierre's original version of the warp field, since by definition the point at the centre of the warp bubble moves on a geodesic and is 'massless'. That is, in Alcubierre's original formalism and in the Natário formalism the spaceship is always treated as a test particle, while in the linearized theory we can treat the spaceship as a finite mass object. For both the Alcubierre and Natário warp drives we find that even at low speeds the net (negative) energy stored in the warp fields must be a significant fraction of the mass of the spaceship.

  4. Advanced Ka-Band Transceiver With Monopulse Tracking

    NASA Technical Reports Server (NTRS)

    Khan, Abdur; Hoppe, Dan; Epp, Larry; Perez, Raul

    2006-01-01

    A proposed Ka-band transmitting/ receiving system would embody a unique combination of established and semi-proven design features. The proposed system (see figure) would include a monopulse receiving feedback loop and a mirror that could be moved by piezoelectric actuators in the feedback loop to adjust the aim of the transmitted and received radio beams. Unlike in a phased-array tracking system, phase shifters (which can be complex and expensive) would not be needed in this monopulse tracking system. Moreover, the monopulse-tracking loop could be combined with other subsystems used in established subreflector and antenna designs. The final transmitter power amplifier in the proposed system would be a quasi-optical power amplifier (QOPA) -- a combination of a planar array of 25 amplifiers and corresponding planar arrays of antenna elements, such that free-space power combining would take place at the output.

  5. A personal communications network using a Ka-band satellite

    NASA Technical Reports Server (NTRS)

    Palmer, Larry C.; Laborde, Enrique; Stern, Alan; Sohn, Philip Y.

    1992-01-01

    The feasibility of a personal communications network using portable terminals that can provide 4.8-kb/s voice communications to a hub station via a Ka-band geosynchronous satellite has been investigated. Tradeoffs are examined so that the combined system of hub and gateway earth stations, the satellite, and the personal terminals can provide a competitive service in terms of cost, availability, and quality. A baseline system that uses a spacecraft with approximately 140 spot beams to cover the contiguous US (CONUS) and 5-W power amplifiers in each beam is described. Satellite access in both the forward and return directions uses frequency-division multiple-access/code-division multiple-access (FDMA/CDMA) with a chip rate of 2.5 Mchip/s.

  6. Calculated pKa Variations Expose Dynamic Allosteric Communication Networks.

    PubMed

    Lang, Eric J M; Heyes, Logan C; Jameson, Geoffrey B; Parker, Emily J

    2016-02-17

    Allosteric regulation of protein function, the process by which binding of an effector molecule provokes a functional response from a distal site, is critical for metabolic pathways. Yet, the way the allosteric signal is communicated remains elusive, especially in dynamic, entropically driven regulation mechanisms for which no major conformational changes are observed. To identify these dynamic allosteric communication networks, we have developed an approach that monitors the pKa variations of ionizable residues over the course of molecular dynamics simulations performed in the presence and absence of an allosteric regulator. As the pKa of ionizable residues depends on their environment, it represents a simple metric to monitor changes in several complex factors induced by binding an allosteric effector. These factors include Coulombic interactions, hydrogen bonding, and solvation, as well as backbone motions and side chain fluctuations. The predictions that can be made with this method concerning the roles of ionizable residues for allosteric communication can then be easily tested experimentally by changing the working pH of the protein or performing single point mutations. To demonstrate the method's validity, we have applied this approach to the subtle dynamic regulation mechanism observed for Neisseria meningitidis 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase, the first enzyme of aromatic biosynthesis. We were able to identify key communication pathways linking the allosteric binding site to the active site of the enzyme and to validate these findings experimentally by reestablishing the catalytic activity of allosterically inhibited enzyme via modulation of the working pH, without compromising the binding affinity of the allosteric regulator.

  7. Miniaturized Ka-Band Dual-Channel Radar

    NASA Technical Reports Server (NTRS)

    Hoffman, James P.; Moussessian, Alina; Jenabi, Masud; Custodero, Brian

    2011-01-01

    Smaller (volume, mass, power) electronics for a Ka-band (36 GHz) radar interferometer were required. To reduce size and achieve better control over RFphase versus temperature, fully hybrid electronics were developed for the RF portion of the radar s two-channel receiver and single-channel transmitter. In this context, fully hybrid means that every active RF device was an open die, and all passives were directly attached to the subcarrier. Attachments were made using wire and ribbon bonding. In this way, every component, even small passives, was selected for the fabrication of the two radar receivers, and the devices were mounted relative to each other in order to make complementary components isothermal and to isolate other components from potential temperature gradients. This is critical for developing receivers that can track each other s phase over temperature, which is a key mission driver for obtaining ocean surface height. Fully hybrid, Ka-band (36 GHz) radar transmitter and dual-channel receiver were developed for spaceborne radar interferometry. The fully hybrid fabrication enables control over every aspect of the component selection, placement, and connection. Since the two receiver channels must track each other to better than 100 millidegrees of RF phase over several minutes, the hardware in the two receivers must be "identical," routed the same (same line lengths), and as isothermal as possible. This level of design freedom is not possible with packaged components, which include many internal passive, unknown internal connection lengths/types, and often a single orientation of inputs and outputs.

  8. Driving Anger and Driving Behavior in Adults with ADHD

    ERIC Educational Resources Information Center

    Richards, Tracy L.; Deffenbacher, Jerry L.; Rosen, Lee A.; Barkley, Russell A.; Rodricks, Trisha

    2006-01-01

    Objective: This study assesses whether anger in the context of driving is associated with the negative driving outcomes experienced by individuals with ADHD. Method: ADHD adults (n = 56) complete measures of driving anger, driving anger expression, angry thoughts behind the wheel, and aggressive, risky, and crash-related behavior. Results are…

  9. DEDRICK DRIVE, LOOKING NORTH FROM SOUTH END OF DEDRICK DRIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DEDRICK DRIVE, LOOKING NORTH FROM SOUTH END OF DEDRICK DRIVE NEAR BUILDING 80 - Pacific Coast Torpedo Station, Keyport Industrial District, Both sides of Second Street, between Dedrick Drive and Liberty Bay and one building west of Dedrick Drive and south of Second Street, Keyport, Kitsap County, WA

  10. Heat loss analysis of a 10 kA warm dielectric HTS DC cable

    NASA Astrophysics Data System (ADS)

    Dai, Shaotao; Xiao, Liye; Teng, Yuping; Song, Naihao; Gao, Zhiyuan; Zhu, Zhiqing; Liang, Xueming; Cao, Zhicheng; Zhang, Dong; Ma, Tao; Zhang, Hongen; Lin, Liangzhen

    2014-09-01

    A 10 kA/360 m warm-dielectric high-temperature superconducting direct current (DC) power cable system (10 kA cable), supported jointly the Chinese government and industrial enterprise, was developed and has been operating as a branch circuit to transmit power for a 320 kA aluminum electrolyzing production line for more than 10 months at an industrial plant in central China. Both the 10 kA cable and its supporting system of the cable system are introduced. The cryogenic system for the 10 kA cable adopts closed loop and the sub-cooled liquid nitrogen is forced to flow inside by a pump. The design of corrugated cryogenic envelope pipe is modularized and every independent module has two standardized joints, which makes it easy to integrate with the other pipes and the terminations. The heat loss sources and the structure including both the termination and the cryogenic envelope pipe of the 10 kA cable are discussed. The total heat loss of the 10 kA cable excluding the loss of cryogenic pipe for liquid nitrogen backward flowing is designed to be less than 1698 W at 10 kA, and the heat loss was compared and discussed with that of the aluminum bar. The field test and commissioning of the cable show that the 10 kA cable performs steadily and its heat loss is less than the expected value.

  11. Driving anger in Malaysia.

    PubMed

    Sullman, Mark J M; Stephens, Amanda N; Yong, Michelle

    2014-10-01

    The present study examined the types of situations that cause Malaysian drivers to become angry. The 33-item version of the driver anger scale (Deffenbacher et al., 1994) was used to investigate driver anger amongst a sample of 339 drivers. Confirmatory factor analysis showed that the fit of the original six-factor model (discourtesy, traffic obstructions, hostile gestures, slow driving, illegal driving and police presence), after removing one item and allowing three error pairs to covary, was satisfactory. Female drivers reported more anger, than males, caused by traffic obstruction and hostile gestures. Age was also negatively related to five (discourtesy, traffic obstructions, hostile gestures, slow driving and police presence) of the six factors and also to the total DAS score. Furthermore, although they were not directly related to crash involvement, several of the six forms of driving anger were significantly related to the crash-related conditions of: near misses, loss of concentration, having lost control of a vehicle and being ticketed. Overall the pattern of findings made in the present research were broadly similar to those from Western countries, indicating that the DAS is a valid measure of driving anger even among non-European based cultures.

  12. Proteolytic fragments of laminin promote excitotoxic neurodegeneration by up-regulation of the KA1 subunit of the kainate receptor.

    PubMed

    Chen, Zu-Lin; Yu, Huaxu; Yu, Wei-Ming; Pawlak, Robert; Strickland, Sidney

    2008-12-29

    Degradation of the extracellular matrix (ECM) protein laminin contributes to excitotoxic cell death in the hippocampus, but the mechanism of this effect is unknown. To study this process, we disrupted laminin gamma1 (lamgamma1) expression in the hippocampus. Lamgamma1 knockout (KO) and control mice had similar basal expression of kainate (KA) receptors, but the lamgamma1 KO mice were resistant to KA-induced neuronal death. After KA injection, KA1 subunit levels increased in control mice but were unchanged in lamgamma1 KO mice. KA1 levels in tissue plasminogen activator (tPA)-KO mice were also unchanged after KA, indicating that both tPA and laminin were necessary for KA1 up-regulation after KA injection. Infusion of plasmin-digested laminin-1 into the hippocampus of lamgamma1 or tPA KO mice restored KA1 up-regulation and KA-induced neuronal degeneration. Interfering with KA1 function with a specific anti-KA1 antibody protected against KA-induced neuronal death both in vitro and in vivo. These results demonstrate a novel pathway for neurodegeneration involving proteolysis of the ECM and KA1 KA receptor subunit up-regulation.

  13. U.S. DRIVE

    SciTech Connect

    2012-03-16

    U.S. DRIVE, which stands for United States Driving Research and Innovation for Vehicle efficiency and Energy sustainability, is an expanded government-industry partnership among the U.S. Department of Energy; USCAR, representing Chrysler Group LLC, Ford Motor Company and General Motors; Tesla Motors; five energy companies – BP America, Chevron Corporation, ConocoPhillips, ExxonMobil Corporation, and Shell Oil Products US; two utilities – Southern California Edison and Michigan-based DTE Energy; and the Electric Power Research Institute (EPRI). The U.S. DRIVE mission is to accelerate the development of pre-competitive and innovative technologies to enable a full range of affordable and clean advanced light-duty vehicles, as well as related energy infrastructure.

  14. Ceramic vane drive joint

    DOEpatents

    Smale, Charles H.

    1981-01-01

    A variable geometry gas turbine has an array of ceramic composition vanes positioned by an actuating ring coupled through a plurality of circumferentially spaced turbine vane levers to the outer end of a metallic vane drive shaft at each of the ceramic vanes. Each of the ceramic vanes has an end slot of bow tie configuration including flared end segments and a center slot therebetween. Each of the vane drive shafts has a cross head with ends thereof spaced with respect to the sides of the end slot to define clearance for free expansion of the cross head with respect to the vane and the cross head being configured to uniformly distribute drive loads across bearing surfaces of the vane slot.

  15. Current drive, anticurrent drive, and balanced injection

    SciTech Connect

    von Goeler, S.; Stevens, J.; Beiersdorfer, P.; Bell, R.; Bernabei, S.; Bitter, M.; Cavallo, A.; Chu, T.K.; Fishman, H.; Hill, K.

    1987-08-01

    In lower hybrid (LH) discharges, the number of suprathermal electrons is limited by the upper bound on the current density from the q = 1 condition, which is caused by the onset of the m = 1 MHD instability. The stored energy of suprathermal electrons, measured in terms of a poloidal beta, scales with plasma current as I/sub p//sup -1/. Potentially, these bounds represent very restrictive conditions for heating in larger machines. Consequently, it seems necessary to perform experiments where the electrons are driven in both directions, parallel and antiparallel to the magnetic field, i.e., bidirectional scenarios like anticurrent drive or balanced injection. Data from PLT relevant to these ideas are discussed. 6 refs., 4 figs.

  16. Dating North European mammoths (Mammuthus primigenius Blum.): a nearly continuous record from 53 ka to 11 ka

    NASA Astrophysics Data System (ADS)

    Ukkonen, P.; Aaris-Sørensen, K.; Arppe, L.; Clark, P. U.; Daugnora, L.; Lister, A.; Lõugas, L.; Seppä, H. A.; Stuart, A. J.; Wojtal, P.; Zupins, I.

    2010-05-01

    nearly continuously from 53 ka to 11 ka, completely disappearing from the area only during the Last Glacial Maximum (LGM). From the northern parts of the study area, mammoths disappeared ca. 27 ka ago. In the south they survived until the LGM, and occupied the area again during deglaciation. Mammoths survived in the eastern part of the study area until the end of Younger Dryas. References Weninger, B., Jöris, O., 2008. A 14C age calibration curve for the last 60 ka: the Greenland-Hulu U/Th timescale and its impact on understanding the Middle to Upper Paleolithic transition in Western Eurasia. Journal of Human Evolution 55,772-781. Weninger, B., Jöris, O., Danzeglocke, U., 2008. CalPal-2007. Cologne Radiocarbon Calibration & Palaeoclimate Research Package. http://www.calpal.de/ [2008-09-18].

  17. Increasing Diversity in STEM through Ka Hikina O Ka Lā Summer Bridge Program for Native Hawaiian Students

    NASA Astrophysics Data System (ADS)

    Coopersmith, A.; Cie, D. K.; Calder, S.; Naho`olewa, D.; Rai, B.

    2014-12-01

    The Advanced Technology Solar Telescope (ATST) Mitigation Initiative and the Kahikina O Ka Lā Program are NSF-funded projects at the University of Hawai`i Maui College. These projects offer instruction and activities intended to increase diversity in STEM careers. Ke Alahaka, the 2014 summer bridge program, was offered to Native Hawaiian high-school students who indicated an interest in STEM areas. Content workshops were offered in Marine Science, Physics, Biotechnology, and Computer Science and Engineering as well as a Hawaiian Studies course designed to provide a cultural context for the STEM instruction. Focus groups and other program assessments indicate that 50% of the students attending the workshops intend to pursue a STEM major during their undergraduate studies.

  18. Ka mauli o ka 'oina a he mauli kanaka: an ethnographic study from an Hawaiian sense of place.

    PubMed

    Oneha, M F

    2001-09-01

    Ka Mauli O Ka 'Aina A He Mauli Kanaka: The Life of the Land is the Life of the People. A sense of place has been directly linked to spiritual well being for all indigenous peoples. Yet, there is minimal evidence that demonstrates understanding and awareness of indigenous health issues from this perspective. Health, or the lack of it, appears to be related to place or the loss of it. Issues of Hawaiian health are inseparable from issues of land, water, and atmosphere. The purpose of this research study was to explore the experience of a sense of place and its relationship to health as perceived and experienced by Hawaiian participants living in Wai'anae, Hawai'i. Thirteen adult men and women, ranging in age from 36 to 80 years, participated in this ethnographic study. Two interviews conducted with each participant addressed the research question, "What is the experience of the relationship between a sense of place and health for Hawaiians?" Participants were also asked to photograph how they experienced this relationship. The qualitative data analysis computer software, Atlas.ti, was used to assist in data analysis. The findings suggest that the relationship between sense of place and health embodies four categories: (1) relationship to akua (god, spirit), (2) relationship to natural elements, (3) relationship to self and others, and (4) belonging to a particular place. Three major traditional Hawaiian concepts, which defined how the relationship between sense of place and health are experienced, were pono, mana, and kuleana. The relationship between these concepts revealed five cultural themes. Health for Hawaiians: I. is having a spiritual connection to their ancestral place; II. relates to the past, present, and future; III. is experienced with intention and understanding; IV. means an openness to the flow and use of energy; and V. is experienced as a pu'uhonua or safe place. These themes suggest implications for Hawaiian health education, practice, and further

  19. LCLS Injector Drive Laser

    SciTech Connect

    Dowell, D.H.; Castro, J.; Emma, P.; Frisch, J.; Gilevich, A.; Hays, G.; Hering, P.; Limborg-Deprey, C.; Loos, H.; Miahnahri, A.; White, W.; /SLAC

    2007-11-02

    Requirements for the LCLS injector drive laser present significant challenges to the design of the system. While progress has been demonstrated in spatial shape, temporal shape, UV generation and rep-rate, a laser that meets all of the LCLS specifications simultaneously has yet to be demonstrated. These challenges are compounded by the stability and reliability requirements. The drive laser and transport system has been installed and tested. We will report on the current operational state of the laser and plans for future improvements.

  20. Pulsation driving and convection

    NASA Astrophysics Data System (ADS)

    Antoci, Victoria

    2015-08-01

    Convection in stellar envelopes affects not only the stellar structure, but has a strong impact on different astrophysical processes, such as dynamo-generated magnetic fields, stellar activity and transport of angular momentum. Solar and stellar observations from ground and space have shown that the turbulent convective motion can also drive global oscillations in many type of stars, allowing to study stellar interiors at different evolutionary stages. In this talk I will concentrate on the influence of convection on the driving of stochastic and coherent pulsations across the Hertzsprung-Russell diagram and give an overview of recent studies.

  1. CONTROL ROD DRIVE

    DOEpatents

    Chapellier, R.A.; Rogers, I.

    1961-06-27

    Accurate and controlled drive for the control rod is from an electric motor. A hydraulic arrangement is provided to balance a piston against which a control rod is urged by the application of fluid pressure. The electric motor drive of the control rod for normal operation is made through the aforementioned piston. In the event scramming is required, the fluid pressure urging the control rod against the piston is relieved and an opposite fluid pressure is applied. The lack of mechanical connection between the electric motor and control rod facilitates the scramming operation.

  2. New insights on water level variability for Lake Turkana for the past 15 ka and at 150 ka from relict beaches

    NASA Astrophysics Data System (ADS)

    Forman, S. L.; Wright, D.

    2015-12-01

    Relict beaches adjacent to Lake Turkana provide a record of water level variability for the Late Quaternary. This study focused on deciphering the geomorphology, sedimentology, stratigraphy and 14C chronology of strand plain sequences in the Kalokol and Lothagam areas. Nine >30 m oscillations in water level were documented between ca. 15 and 4 ka. The earliest oscillation between ca. 14.5 and 13 ka is not well constrained with water level to at least 70 m above the present surface and subsequently fell to at least 50 m. Lake level increased to ~ 90 m between ca. 11.2 and 10.4 ka, post Younger Dryas cooling. Water level fell by >30 m by 10.2 ka, with another potential rise at ca. 8.5 ka to >70 m above current level. Lake level regressed by > 40 m at 8.2 ka coincident with cooling in the equatorial Eastern Atlantic Ocean. Two major >70 m lake level oscillations centered at 6.6 and 5.2 ka may reflect enhanced convection with warmer sea surface temperatures in the Western Indian Ocean. The end of the African Humid Period occurred from ca. 8.0 to 4.5 ka and was characterized by variable lake level (± > 40 m), rather than one monotonic fall in water level. This lake level variability reflects a complex response to variations in the extent and intensity of the East and West African Monsoons near geographic and topographic limits within the catchment of Lake Turkana. Also, for this closed lake basin excess and deficits in water input are amplified with a cascading lake effect in the East Rift Valley and through the Chew Bahir Basin. The final regression from a high stand of > 90 m began at. 5.2 ka and water level was below 20 m by 4.5 ka; and for the remainder of the Holocene. This sustained low stand is associated with weakening of the West African Monsoon, a shift of the mean position of Congo Air Boundary west of the Lake Turkana catchment and with meter-scale variability in lake level linked to Walker circulation across the Indian Ocean. A surprising observation is

  3. No Pass, No Drive?

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2001-01-01

    Discusses basis for Kentucky appellate court decision that state's no-pass, no-drive statute did not violate due-process and equal-protection clauses of the Kentucky and federal constitutions, but did violate the federal Family Education Rights and Privacy Act, but nevertheless did not invalidate the statute. Explains why the decision is…

  4. Drive-Through Training

    ERIC Educational Resources Information Center

    Carter, Margie

    2010-01-01

    In this article, the author discusses how the early childhood field's approach to staff training reflects the drive-through, fast-food culture. Year after year directors send their teachers to workshops to get some quick refresher techniques. The author suggests that rather than focusing professional development on topics, focus on observing…

  5. COMMENT: No warp drive

    NASA Astrophysics Data System (ADS)

    Coule, D. H.

    1998-08-01

    The warp drive spacetime of Alcubierre is impossible to set up without first being able to distribute matter at tachyonic speed, put roughly, you need one to make one! However, over small distances, where the energy conditions possibly can be violated, one can envision opening the light-cones to increase the apparent speed of light.

  6. Magnetized drive fluids

    SciTech Connect

    Rosensweig, R.E.; Zahn, M.

    1986-04-01

    A process is described for recovering a first fluid from a porous subterranean formation which comprises injecting a displacement fluid in an effective amount to displace the first fluid, injecting a ferrofluid, applying a magnetic field containing a gradient of field intensity within the formation, driving the displacement fluid through the formation with the ferrofluid and recovering first fluid.

  7. DrivePy

    SciTech Connect

    King, Ryan; Guo, Yi

    2014-08-30

    DrivePy is physics-based drivetrain model that sizes drivetrain components based on aerodynamic and operational loads for use in a systems engineering model. It also calculates costs based on empirical data collected by NREL's National Wind Technology Center.

  8. CSI: Hard Drive

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  9. Teachers with Drive

    ERIC Educational Resources Information Center

    Coggins, Celine; Diffenbaugh, P. K.

    2013-01-01

    For students in U.S. classrooms today, the odds of being assigned to an inexperienced teacher are higher than they have ever been because so many teachers, some in the top 20 percent of effectiveness are leaving the classroom in their first five years. Coggins and Diffenbaugh turn to Daniel Pink's work on drive to determine how to motivate…

  10. Driving While Intoxicated.

    ERIC Educational Resources Information Center

    Brick, John

    Alcohol intoxication increases the risk of highway accidents, the relative risk of crash probability increasing as a function of blood alcohol content (BAC). Because alcohol use is more prevalent than use of other drugs, more is known about the relationship between alcohol use and driving. Most states presume a BAC of .10% to be evidence of drunk…

  11. Photonically enabled Ka-band radar and infrared sensor subscale testbed

    NASA Astrophysics Data System (ADS)

    Lohr, Michele B.; Sova, Raymond M.; Funk, Kevin B.; Airola, Marc B.; Dennis, Michael L.; Pavek, Richard E.; Hollenbeck, Jennifer S.; Garrison, Sean K.; Conard, Steven J.; Terry, David H.

    2014-10-01

    A subscale radio frequency (RF) and infrared (IR) testbed using novel RF-photonics techniques for generating radar waveforms is currently under development at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to study target scenarios in a laboratory setting. The linearity of Maxwell's equations allows the use of millimeter wavelengths and scaled-down target models to emulate full-scale RF scene effects. Coupled with passive IR and visible sensors, target motions and heating, and a processing and algorithm development environment, this testbed provides a means to flexibly and cost-effectively generate and analyze multi-modal data for a variety of applications, including verification of digital model hypotheses, investigation of correlated phenomenology, and aiding system capabilities assessment. In this work, concept feasibility is demonstrated for simultaneous RF, IR, and visible sensor measurements of heated, precessing, conical targets and of a calibration cylinder. Initial proof-of-principle results are shown of the Ka-band subscale radar, which models S-band for 1/10th scale targets, using stretch processing and Xpatch models.

  12. Study of the 100 fs 10 kA X-band linac

    NASA Astrophysics Data System (ADS)

    Takeshita, A.; Uesaka, M.; Watanabe, Tomoyuki; Yamamoto, Masashi; Kaneko, Namio

    1999-01-01

    Design and numerical analysis of an X-band femtosecond electron linear accelerator (linac) is presented. We aim to generate a 100 fs (full width at half maxium: FWHM) electron single bunch with more than 1 nC at the X-band femtosecond linac. The simulation of electron dynamics including magnetic pulse compression is carried out by using PARMELA and SUPERFISH. It is found that the 700 ps (tail-to-tail) electron emission from a 150 kV thermionic gun can be bunched and compressed to 100 fs (FWHM) electron single bunch with the charge of 1 nC which gives 10 kA. We plan to use one high power X-band klystron which can supply 60 MW with more than 200 ns pulse duration. The flatness of plateau of the RF pulse should be 0.2% for stable ultrashort bunch generation. The influence of the klystron voltage fluctuation on the accelerating voltage is quantitatively evaluated and the vacuum design is also done. We have confirmed the feasibility of the linac from viewpoints of state-of the-art technologies.

  13. Highly Efficient Amplifier for Ka-Band Communications

    NASA Technical Reports Server (NTRS)

    1996-01-01

    An amplifier developed under a Small Business Innovation Research (SBIR) contract will have applications for both satellite and terrestrial communications. This power amplifier uses an innovative series bias arrangement of active devices to achieve over 40-percent efficiency at Ka-band frequencies with an output power of 0.66 W. The amplifier is fabricated on a 2.0- by 3.8-square millimeter chip through the use of Monolithic Microwave Integrated Circuit (MMIC) technology, and it uses state-of-the-art, Pseudomorphic High-Electron-Mobility Transistor (PHEMT) devices. Although the performance of the MMIC chip depends on these high-performance devices, the real innovations here are a unique series bias scheme, which results in a high-voltage chip supply, and careful design of the on-chip planar output stage combiner. This design concept has ramifications beyond the chip itself because it opens up the possibility of operation directly from a satellite power bus (usually 28 V) without a dc-dc converter. This will dramatically increase the overall system efficiency. Conventional microwave power amplifier designs utilize many devices all connected in parallel from the bias supply. This results in a low-bias voltage, typically 5 V, and a high bias current. With this configuration, substantial I(sup 2) R losses (current squared times resistance) may arise in the system bias-distribution network. By placing the devices in a series bias configuration, the total current is reduced, leading to reduced distribution losses. Careful design of the on-chip planar output stage power combiner is also important in minimizing losses. Using these concepts, a two-stage amplifier was designed for operation at 33 GHz and fabricated in a standard MMIC foundry process with 0.20-m PHEMT devices. Using a 20-V bias supply, the amplifier achieved efficiencies of over 40 percent with an output power of 0.66 W and a 16-dB gain over a 2-GHz bandwidth centered at 33 GHz. With a 28-V bias, a power

  14. Modeling of rf-assisted helicity injection start-up and current drive

    SciTech Connect

    Hwang, Y.S.; Ono, M. )

    1994-10-15

    DC-helicity injection has been successfully applied to the tokamak start-up on CDX-U and CCT tokamaks. Furthermore, CDX-U achieved plasma current levels of up to 10 kA from zero without any ohmic drive. Helicity balance and scaling from CDX-U experiments indicate that plasma current scales with the electron temperature as [ital T][sub [ital e

  15. Ka Hana `Imi Na`auao: A Science Curriculum Project

    NASA Astrophysics Data System (ADS)

    Napeahi, K.; Roberts, K. D.; Galloway, L. M.; Stodden, R. A.; Akuna, J.; Bruno, B.

    2005-12-01

    In antiquity, the first people to step foot on what are now known as the Hawaiian islands skillfully traversed the Pacific Ocean using celestial navigation and learned observations of scientific phenomena. Long before the Western world ventured beyond the horizon, Hawaiians had invented the chronometer, built aqueduct systems (awai) that continue to amaze modern engineers, and had preventive health systems as well as a comprehensive knowledge of medicinal plants (including antivirals) which only now are working their way through trials for use in modern pharmacopia. Yet, today, Native Hawaiians are severely underrepresented in science-related fields, reflecting (in part) a failure of the Western educational system to nurture the potential of these resourceful students, particularly the many "at-risk" students who are presently over-represented in special education. A curriculum which draws from and incorporates traditional Hawaiian values and knowledge is needed to reinforce links to the inquiry process which nurtured creative thinking during the renaissance of Polynesian history. The primary goal of the Ka Hana `Imi Na`auao Project (translation: `science` or `work in which you seek enlightenment, knowledge or wisdom`) is to increase the number of Native Hawaiian adults in science-related postsecondary education and employment fields. Working closely with Native Hawaiian cultural experts and our high school partners, we will develop and implement a culturally responsive 11th and 12th grade high school science curriculum, infused with math, literacy and technology readiness skills. Software and assistive technology will be used to adapt instruction to individual learners` reading levels, specific disabilities and learning styles. To ease the transition from secondary to post-secondary education, selected grade 12 students will participate in planned project activities that link high school experiences with college science-related programs of study. Ka Hana `Imi Na

  16. Did the 8.2 ka event affect southern Africa?

    NASA Astrophysics Data System (ADS)

    Shaw, Paul

    2014-05-01

    Palaeoenvironmental reconstruction of southern Africa over the past 4 decades has focused largely on the last glacial cycle, and, more recently, events during to Holocene, interpreted largely at the millennial scale. Little attention has been given to sub-millenial drivers and impacts, other than the Little Ice Age (HolmgreN et al 2001). The 8.2ka event has been recognized in Europe for over half a century from peat cores and dendrochronology. A Bond Event caused by disruption of the Gulf Stream by melting Laurentian ice, it lasted around 100 years and resulted in a fall in temperature in northern Europe of up to 6o C. Recently published high-resolution speleothem records have indicated significant short-term change over a much wider area than previously thought, including the Caribbean, eastern Brazil, Spain, Oman and China. A recent paper on Trinidad (Boyd et al, in press) emphasizes a period of prolonged drought in the southern Caribbean due to a southerly emplacement of the ITCZ. The question then arises whether this shift affected the southern hemisphere, and if so, what would be the likely impacts and evidence. A study of late Quaternary lake levels in Lake Chilwa, Malawi (Thomas et al 2009) noted a correspondence between high lake stands and Heinrich events, whilst modeling of Atlantic freshwater influx using the HadCM3 GCM indicates negative precipitation anomalies in the Caribbean and west Africa, with a significant positive anomaly in the interior of southern Africa, possibly linked to enhanced monsoonal activity in the Indian Ocean. These patterns in southern and western Africa have been suggested around 8.2 ka in a review of early Holocene data (Burrough & Thomas 2013), but the chronological resolution is not sufficient to conclude the observation. The only speleothem record for this period, T8 in Cold Air Cave, Makapansgat Valley (Holmgren et al 2003) shows an anomaly, but with temporal resolution at a 50 yr sampling interval, this again is speculative

  17. X/X/Ka-band prime focus feed antenna for the Mars Observer beacon spacecraft

    NASA Technical Reports Server (NTRS)

    Stanton, P.; Reilly, H.; Esquivel, M.

    1988-01-01

    The results of an X/X/Ka-band feed design concept demonstration are presented. The purpose is to show the feasibility of adding a Ka-band beacon to the Mars Observer spacecraft. Scale model radiation patterns were made and analyzed.

  18. School Ka Sabaq: Literacy in a Girls' Primary School in Rural Pakistan.

    ERIC Educational Resources Information Center

    Farah, Iffat

    Literacy learning practices in the context of a girls' school in Pakistan are described as part of a larger study. "School ka sabaq" or "school lesson" is recognized as involving reading and writing activities as well as behavior particular to the institution of the school. The goals of school ka sabaq, which are to pass exams and acquire…

  19. High speed transfer switch with 50 kA and 50 kV

    SciTech Connect

    Reass, W.A.; Kasik, R.J.; Wilds, W.A.

    1989-01-01

    This paper gives the mechanical design and electrical parameters of a pneumatically operated transfer switch. This design is used to switch 3-second 50-kA current pulses, and is easily capable of 75 kA operation (2 {times} 10{sup 10} I{sup 2}t); with water-cooled versions capable of 20 kA continuously. Although the switch is not specifically designed to make or break 50 kA, it is provided with auxiliary Elkonite arcing contacts have proven their value in protecting the main electrodes even under repetitive (50 kA) fault conditions. Included in this presentation will be the results of extensive life testing and associated criteria. 6 figs., 1 tab.

  20. X-/Ka-band dichroic plate design and grating lobe study

    NASA Technical Reports Server (NTRS)

    Chen, J. C.

    1991-01-01

    An X-/Ka-band dichroic plate is needed for simultaneously receiving X-band and Ka-band in the DSS-13 Beam Waveguide Antenna. The plate is transparent to the allocated Ka-band downlink (31.8-32.3 GHz) and the frequency band for the Mars Observer Ka-band Beacon Link Experiment (KABLE) (33.6-33.8 GHz), while at the same time reflecting the X-band downlink (8.4-8.5 GHz). The design is made using a computer program for dichroic plates with rectangular holes. The theoretical performance of the X-/Ka-band dichroic plate is presented. A study of the grating lobe problem is also included in this article.

  1. The intrinsic pKa values for phosphatidylserine and phosphatidylethanolamine in phosphatidylcholine host bilayers.

    PubMed Central

    Tsui, F C; Ojcius, D M; Hubbell, W L

    1986-01-01

    Potentiometric titrations and surface potential measurements have been used to determine the intrinsic pKa values of both the carboxyl and amino groups of phosphatidylserine (PS) in mixed vesicles of PS and phosphatidylcholine (PC), and also of the amino group of phosphatidylethanolamine (PE) in mixed PE-PC vesicles. The pKa of the carboxyl group of PS in liposomes with different PS/PC lipid ratios measured by the two different methods is 3.6 +/- 0.1, and the pKa of its amino group is 9.8 +/- 0.1. The pKa of the amino group of PE in PE-PC vesicles, determined solely by surface potential measurements, is 9.6 +/- 0.1. These pKa values are independent of the aqueous phase ionic strength and of the effect of the liposome's surface potential due to the presence of these partially charged lipids. PMID:3955180

  2. Absolute paleointensity from Hawaiian lavas younger than 35 ka

    USGS Publications Warehouse

    Valet, J.-P.; Tric, E.; Herrero-Bervera, E.; Meynadier, L.; Lockwood, J.P.

    1998-01-01

    Paleointensity studies have been conducted in air and in argon atmosphere on nine lava flows with radiocarbon ages distributed between 3.3 and 28.2 ka from the Mauna Loa volcano in the big island of Hawaii. Determinations of paleointensity obtained at eight sites depict the same overall pattern as the previous results for the same period in Hawaii, although the overall average field intensity appears to be lower. Since the present results were determined at higher temperatures than in the previous studies, this discrepancy raises questions regarding the selection of low versus high-temperature segments that are usually made for absolute paleointensity. The virtual dipole moments are similar to those displayed by the worldwide data set obtained from dated lava flows. When averaged within finite time intervals, the worldwide values match nicely the variations of the Sint-200 synthetic record of relative paleointensity and confirm the overall decrease of the dipole field intensity during most of this period. The convergence between the existing records at Hawaii and the rest of the world does not favour the presence of persistent strong non-dipole components beneath Hawaii for this period.

  3. Rain Fade Compensation for Ka-Band Communications Satellites

    NASA Technical Reports Server (NTRS)

    Mitchell, W. Carl; Nguyen, Lan; Dissanayake, Asoka; Markey, Brian; Le, Anh

    1997-01-01

    This report provides a review and evaluation of rain fade measurement and compensation techniques for Ka-band satellite systems. This report includes a description of and cost estimates for performing three rain fade measurement and compensation experiments. The first experiment deals with rain fade measurement techniques while the second one covers the rain fade compensation techniques. The third experiment addresses a feedback flow control technique for the ABR service (for ATM-based traffic). The following conclusions were observed in this report; a sufficient system signal margin should be allocated for all carriers in a network, that is a fixed clear-sky margin should be typically in the range of 4-5 dB and should be more like 15 dB in the up link for moderate and heavy rain zones; to obtain a higher system margin it is desirable to combine the uplink power control technique with the technique that implements the source information rate and FEC code rate changes resulting in a 4-5 dB increase in the dynamic part of the system margin. The experiments would assess the feasibility of the fade measurements and compensation techniques, and ABR feedback control technique.

  4. A dual frequency microstrip antenna for Ka band

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Baddour, M. F.

    1985-01-01

    For fixed satellite communication systems at Ka band with downlink at 17.7 to 20.2 GHz and uplink at 27.5 to 30.0 GHz, the focused optics and the unfocused optics configurations with monolithic phased array feeds have often been used to provide multiple fixed and multiple scanning spot beam coverages. It appears that a dual frequency microstrip antenna capable of transmitting and receiving simultaneously is highly desirable as an array feed element. This paper describes some early efforts on the development and experimental testing of a dual frequency annular microstrip antenna. The antenna has potential application for use in conjunction with a monolithic microwave integrated circuit device as an active radiating element in a phased array of phased array feeds. The antenna is designed to resonate at TM sub 12 and TM sub 13 modes and tuned with a circumferential microstrip ring to vary the frequency ratio. Radiation characteristics at both the high and low frequencies are examined. Experimental results including radiating patterns and swept frequency measurements are presented.

  5. Experimental approaches for measuring pKa's in RNA and DNA.

    PubMed

    Thaplyal, Pallavi; Bevilacqua, Philip C

    2014-01-01

    RNA and DNA carry out diverse functions in biology including catalysis, splicing, gene regulation, and storage of genetic information. Interest has grown in understanding how nucleic acids perform such sophisticated functions given their limited molecular repertoire. RNA can fold into diverse shapes that often perturb pKa values and allow it to ionize appreciably under biological conditions, thereby extending its molecular diversity. The goal of this chapter is to enable experimental measurement of pKa's in RNA and DNA. A number of experimental methods for measuring pKa values in RNA and DNA have been developed over the last 10 years, including RNA cleavage kinetics; UV-, fluorescence-, and NMR-detected pH titrations; and Raman crystallography. We begin with general considerations for choosing a pKa assay and then describe experimental conditions, advantages, and disadvantages for these assays. Potential pitfalls in measuring a pKa are provided including the presence of apparent pKa's due to a kinetic pKa or coupled acid- and alkali-promoted RNA unfolding, as well as degradation of RNA, precipitation of metal hydroxides and poor baselines. Use of multiple data fitting procedures and the study of appropriate mutants are described as ways to avoid some of these pitfalls. Application of these experimental methods to RNA and DNA will increase the number of available nucleic acid pKa values in the literature, which should deepen insight into biology and provide benchmarks for pKa calculations. Future directions for measuring pKa's in nucleic acids are discussed.

  6. Formation and stability of N-heterocyclic carbenes in water: the carbon acid pKa of imidazolium cations in aqueous solution.

    PubMed

    Amyes, Tina L; Diver, Steven T; Richard, John P; Rivas, Felix M; Toth, Krisztina

    2004-04-01

    We report second-order rate constants kDO (M-1 s-1) for exchange for deuterium of the C(2)-proton of a series of simple imidazolium cations to give the corresponding singlet imidazol-2-yl carbenes in D2O at 25 degrees C and I = 1.0 (KCl). Evidence is presented that the reverse protonation of imidazol-2-yl carbenes by solvent water is limited by solvent reorganization and occurs with a rate constant of kHOH = kreorg = 10(11) s-1. The data were used to calculate reliable carbon acid pK(a)s for ionization of imidazolium cations at C(2) to give the corresponding singlet imidazol-2-yl carbenes in water: pKa = 23.8 for the imidazolium cation, pKa = 23.0 for the 1,3-dimethylimidazolium cation, pKa = 21.6 for the 1,3-dimethylbenzimidazolium cation, and pKa = 21.2 for the 1,3-bis-((S)-1-phenylethyl)benzimidazolium cation. The data also provide the thermodynamic driving force for a 1,2-hydrogen shift at a singlet carbene: K12 = 5 x 10(16) for rearrangement of the parent imidazol-2-yl carbene to give neutral imidazole in water at 298 K, which corresponds to a favorable Gibbs free energy change of 23 kcal/mol. We present a simple rationale for the observed substituent effects on the thermodynamic stability of N-heterocyclic carbenes relative to a variety of neutral and cationic derivatives that emphasizes the importance of the choice of reference reaction when assessing the stability of N-heterocyclic carbenes.

  7. [Driving ability with multiple sclerosis].

    PubMed

    Küst, J; Dettmers, C

    2014-07-01

    Driving is an important issue for young patients, especially for those whose walking capacity is impaired. Driving might support the patient's social and vocational participation. The question as to whether a patient with multiple sclerosis (MS) is restricted in the ability to drive a car depends on neurological and neuropsychological deficits, self-awareness, insight into deficits and ability to compensate for loss of function. Because of the enormous variability of symptoms in MS the question is highly individualized. A practical driving test under supervision of a driving instructor (possibly accompanied by a neuropsychologist) might be helpful in providing both patient and relatives adequate feedback on driving abilities. PMID:24906536

  8. Advanced Motor Drives Studies

    NASA Technical Reports Server (NTRS)

    Ehsani, M.; Tchamdjou, A.

    1997-01-01

    This report presents an evaluation of advanced motor drive systems as a replacement for the hydrazine fueled APU units. The replacement technology must meet several requirements which are particular to the space applications and the Orbiter in general. Some of these requirements are high efficiency, small size, high power density. In the first part of the study several motors are compared, based on their characteristics and in light of the Orbiter requirements. The best candidate, the brushless DC is chosen because of its particularly good performance with regards to efficiency. Several power electronics drive technologies including the conventional three-phase hard switched and several soft-switched inverters are then presented. In the last part of the study, a soft-switched inverter is analyzed and compared to its conventional hard-switched counterpart. Optimal efficiency is a basic requirement for space applications and the soft-switched technology represents an unavoidable trend for the future.

  9. Forces Driving Chaperone Action.

    PubMed

    Koldewey, Philipp; Stull, Frederick; Horowitz, Scott; Martin, Raoul; Bardwell, James C A

    2016-07-14

    It is still unclear what molecular forces drive chaperone-mediated protein folding. Here, we obtain a detailed mechanistic understanding of the forces that dictate the four key steps of chaperone-client interaction: initial binding, complex stabilization, folding, and release. Contrary to the common belief that chaperones recognize unfolding intermediates by their hydrophobic nature, we discover that the model chaperone Spy uses long-range electrostatic interactions to rapidly bind to its unfolded client protein Im7. Short-range hydrophobic interactions follow, which serve to stabilize the complex. Hydrophobic collapse of the client protein then drives its folding. By burying hydrophobic residues in its core, the client's affinity to Spy decreases, which causes client release. By allowing the client to fold itself, Spy circumvents the need for client-specific folding instructions. This mechanism might help explain how chaperones can facilitate the folding of various unrelated proteins. PMID:27293188

  10. Drive-by-Downloads

    SciTech Connect

    Narvaez, Julia; Endicott-Popovsky, Barbara E.; Seifert, Christian; Aval, Chiraag U.; Frincke, Deborah A.

    2010-02-01

    Abstract: Drive-by-downloads are malware that push, and then execute, malicious code on a client system without the user's consent. The purpose of this paper is to introduce a discussion of the usefulness of antivirus software for detecting the installation of such malware, providing groundwork for future studies. Client honeypots collected drive-by malware which was then evaluated using common antivirus products. Initial analysis showed that most of such antivirus products identified less than 70% of these highly polymorphic malware programs. Also, it was observed that the antivirus products tested, even when successfully detecting this malware, often failed to classify it, leading to the conclusion that further work could involve not only developing new behavioral detection technologies, but also empirical studies that improve general understanding of these threats. Toward that end, one example of malicious code was analyzed behaviorally to provide insight into next steps for the future direction of this research.

  11. Gear Drive Testing

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Philadelphia Gear Corporation used two COSMIC computer programs; one dealing with shrink fit analysis and the other with rotor dynamics problems in computerized design and test work. The programs were used to verify existing in-house programs to insure design accuracy by checking its company-developed computer methods against procedures developed by other organizations. Its specialty is in custom units for unique applications, such as Coast Guard ice breaking ships, steel mill drives, coal crusher, sewage treatment equipment and electricity.

  12. Gulf of California Sediment and Proxy SST Records Suggest a Post 6 ka Development of the Arizona Monsoon and Solar Forcing of Cycles

    NASA Astrophysics Data System (ADS)

    Barron, J. A.; Bukry, D.

    2007-12-01

    Summer monsoonal rains in Arizona and adjacent areas are mainly due to pulses of moisture traveling northward up the Gulf of California (GOC). Modern studies reveal that northern GOC SSTs must exceed 26 deg. C before monsoonal rainfall develops in Arizona and western New Mexico, and over 80 percent of the rainfall in this region occurs after northern GOC SSTs exceed 28.5 deg. C. Warming of GOC occurs progressively from south to north in the late spring, as northwest winds, which dominate in the late fall to early spring, decrease in strength, and tropical waters penetrate northward along the western coast of the GOC. Sediment (CaCO3 and opal) and microfossil (diatom and silicoflagellate) proxies spanning the past 15,000 years from cores in the central GOC suggest that waters of the northern GOC were too cold between ca. 11 and 6 ka to allow development of monsoonal rains in Arizona. Evidence for a post 6 ka intensification of monsoonal rains in Arizona and adjacent areas includes: 1) increased frequency of arroyo cutting in Arizona after ca. 5 ka, 2) increased evidence of paleofloods in Arizona and SW Utah after ca. 6 ka, and 3) the renewal of aggradation of alluvial fans in the Mojave Dessert at ca. 6 ka after a lull in their formation between ca. 11 and 6 ka. Supportive pollen evidence includes : 1) the late Holocene appearance of summer flowering annuals and C-{4} grasses in SE Arizona, and 2) the post 6 ka appearance of a warm, mixed biome in the highlands of northwest Mexico. Other pollen evidence and the scarcity of early and middle Holocene packrat middens in the American southwest, however, have been cited as evidence of increased monsoonal rains during the early and middle parts of the Holocene It is likely that the Gulf of Mexico was the main source of monsoonal moisture in the American southwest prior to ca. 6 ka, especially in the regions east of Arizona. A northward displacement of the Intertropical Convergence Zone in the Caribbean prior to ca. 5.4 ka

  13. The rise and fall of Lake Bonneville between 45 and 10.5 ka

    USGS Publications Warehouse

    Benson, L.V.; Lund, S.P.; Smoot, J.P.; Rhode, D.E.; Spencer, R.J.; Verosub, K.L.; Louderback, L.A.; Johnson, C.A.; Rye, R.O.; Negrini, R.M.

    2011-01-01

    A sediment core taken from the western edge of the Bonneville Basin has provided high-resolution proxy records of relative lake-size change for the period 45.1-10.5 calendar ka (hereafter ka). Age control was provided by a paleomagnetic secular variation (PSV)-based age model for Blue Lake core BL04-4. Continuous records of ??18O and total inorganic carbon (TIC) generally match an earlier lake-level envelope based on outcrops and geomorphic features, but with differences in the timing of some hydrologic events/states. The Stansbury Oscillation was found to consist of two oscillations centered on 25 and 24 ka. Lake Bonneville appears to have reached its geomorphic highstand and began spilling at 18.5 ka. The fall from the highstand to the Provo level occurred at 17.0 ka and the lake intermittently overflowed at the Provo level until 15.2 ka, at which time the lake fell again, bottoming out at ~14.7 ka. The lake also fell briefly below the Provo level at ~15.9 ka. Carbonate and ??18O data indicate that between 14.7 and 13.1 ka the lake slowly rose to the Gilbert shoreline and remained at about that elevation until 11.6 ka, when it fell again. Chemical and sedimentological data indicate that a marsh formed in the Blue Lake area at 10.5 ka.Relatively dry periods in the BL04-4 records are associated with Heinrich events H1-H4, suggesting that either the warming that closely followed a Heinrich event increased the evaporation rate in the Bonneville Basin and (or) that the core of the polar jet stream (PJS) shifted north of the Bonneville Basin in response to massive losses of ice from the Laurentide Ice Sheet (LIS) during the Heinrich event. The second Stansbury Oscillation occurred during Heinrich event H2, and the Gilbert wet event occurred during the Younger Dryas cold interval. Several relatively wet events in BL04-4 occur during Dansgaard-Oeschger (DO) warm events.The growth of the Bear River glacier between 32 and 17 ka paralleled changes in the values of proxy

  14. Environmental Crack Driving Force

    NASA Astrophysics Data System (ADS)

    Hall, M. M.

    2013-03-01

    The effect of environment on the crack driving force is considered, first by assuming quasistatic extension of a stationary crack and second, by use of stress corrosion cracking (SCC) crack growth rate models developed previously by this author and developed further here. A quasistatic thermodynamic energy balance approach, of the Griffith-Irwin type, is used to develop stationary crack threshold expressions, tilde{J}_c , which represent the conjoint mechanical and electrochemical conditions, below which stationary cracks are stable. Expressions for the electrochemical crack driving force (CDF) were derived using an analysis that is analogous to that used by Irwin to derive his "strain energy release rate," G, which Rice showed as being equivalent to his mechanical CDF, J. The derivations show that electrochemical CDFs both for active path dissolution (APD) and hydrogen embrittlement (HE) mechanisms of SCC are simply proportional to Tafel's electrochemical anodic and cathodic overpotentials, η a and η c, respectively. Phenomenological SCC models based on the kinetics of APD and HE crack growth are used to derive expressions for the kinetic threshold, J scc, below which crack growth cannot be sustained. These models show how independent mechanical and environmental CDFs may act together to drive SCC crack advance. Development of a user-friendly computational tool for calculating Tafel's overpotentials is advocated.

  15. Who's Driving Home?: Assessing Adolescent Drinking and Driving.

    ERIC Educational Resources Information Center

    Swisher, John D.; Bibeau, Daniel

    1987-01-01

    Data from 13,998 students revealed that high percentages of students drank often and that many of these students reported being drunk often. While most students indicated they would prefer not to drive home after drinking, approximately one-third of driving age students indicated they would drive under the influence of alcohol or would ride with…

  16. Dynamic load sharing for conveyor belts with multiple drive stations

    SciTech Connect

    Churchill, F.T.

    1995-05-01

    The characteristics and limitations of multiple drive station belt conveyors are explored and a computational method is presented as a means of providing drive coordination which can skirt some of the limitations. This paper will describe some of the design parameters of concern for belt conveyors, including belt tension and how it varies with load, how the unpredictably non-uniform loading of the belt affects performance, and will explore the relationship of friction between the belt and a drive pulley and how this limits the amount of horsepower which can be transmitted to the belt. The way in which these parameters change in configurations with multiple drives and multiple drive stations is outlined. The two main means of employing booster drives are presented; tripper booster and linear booster. The tripper booster technology is amenable to tension control, in which the torque provided by each drive station is controlled by the tension in the belt measured immediately downstream of the drive station. This approach has proved successful in belt systems with as many as four booster drive stations, operating at belt loads in excess of 3200 tons per hour over 12,000 ft of belt. The linear booster arrangement does not allow a convenient method of measuring belt tension, thus a computational algorithm was devised to take advantage of the geometry of the belt system to control tension of the belt within certain limits without the use of tension feedback. This approach has proven useful in 10,000 foot belt system which has a single booster drive station, operating at loads up to 4000 tons per hour.

  17. Cyclone Xaver seen by SARAL/AltiKa

    NASA Astrophysics Data System (ADS)

    Scharroo, Remko; Fenoglio, Luciana; Annunziato, Alessandro

    2014-05-01

    During the first week of December 2013, Cyclone Xaver pounded the coasts and the North Sea. On 6 December, all along the Wadden Sea, the barrier islands along the north of the Netherlands and the northwest of Germany experienced record storm surges. We show a comparison of the storm surge measured by the radar altimeter AltiKa on-board the SARAL satellite and various types of in-situ data and models. Two tide gauges along the German North Sea coast, one in the southern harbour of the island of Helgoland and one on an offshore lighthouse Alte Weser, confirmed that the storm drove sea level to about three meters above the normal tide level. Loading effects during the storm are also detected by the GPS measurements at several tide gauge stations. The altimeter in the mean time shows that the storm surge was noticeable as far as 400 km from the coast. The altimeter measured wind speeds of 20 m/s nearly monotonically throughout the North Sea. An offshore anemometer near the island of Borkum corroborated this value. A buoy near the FINO1 offshore platform measured wave heights of 8 m, matching quite well the measurements from the altimeter, ranging from 6 m near the German coast to 12 m further out into the North Sea. Furthermore we compare the altimeter-derived and in-situ sea level, wave height and wind speed products with outputs from the Operation Circulation and Forecast model of the Bundesamt für Seeschifffahrt und Hydrographie (BSH) and with a global storm surge forecast and inundation model of the Joint Research Centre (JRC) of the European Commission. The Operational circulation model of BSH (BSHcmod) and its component, the surge model (BSHsmod), perform daily predictions for the next 72 hours based on the meteorological model of the Deutsche Wetterdienst (DWD). The JRC Storm Surge Calculation System is a new development that has been established at the JRC in the framework of the Global Disasters Alerts and Coordination System (GDACS). The system uses

  18. Studying NASA's Transition to Ka-Band Communications for Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Chelmins, David; Reinhart, Richard; Mortensen, Dale; Welch, Bryan; Downey, Joseph; Evans, Mike

    2014-01-01

    As the S-band spectrum becomes crowded, future space missions will need to consider moving command and telemetry services to Ka-band. NASAs Space Communications and Navigation (SCaN) Testbed provides a software-defined radio (SDR) platform that is capable of supporting investigation of this service transition. The testbed contains two S-band SDRs and one Ka-band SDR. Over the past year, SCaN Testbed has demonstrated Ka-band communications capabilities with NASAs Tracking and Data Relay Satellite System (TDRSS) using both open- and closed-loop antenna tracking profiles. A number of technical areas need to be addressed for successful transition to Ka-band. The smaller antenna beamwidth at Ka-band increases the criticality of antenna pointing, necessitating closed loop tracking algorithms and new techniques for received power estimation. Additionally, the antenna pointing routines require enhanced knowledge of spacecraft position and attitude for initial acquisition, versus an S-band antenna. Ka-band provides a number of technical advantages for bulk data transfer. Unlike at S-band, a larger bandwidth may be available for space missions, allowing increased data rates. The potential for high rate data transfer can also be extended for direct-to-ground links through use of variable or adaptive coding and modulation. Specific examples of Ka-band research from SCaN Testbeds first year of operation will be cited, such as communications link performance with TDRSS, and the effects of truss flexure on antenna pointing.

  19. Standard Observing Bands: Is Now the Time to Replace S/X with X/Ka?

    NASA Astrophysics Data System (ADS)

    Jacobs, Christopher S.; Lanyi, G. E.; Naudet, C. J.

    2004-06-01

    In this paper we will argue that the VLBI community should be developing a road map to transition from S/X to simultaneous X and Ka-band (32 GHz) observations. There are both negative and positive reasons for planning such a transition. On the negative side, we will outline concerns that S-band observations may be headed toward obsolescence. On the positive side, we will refer to evidence that X/Ka has potential for providing a more stable reference frame than S/X. We will propose timetables for a transition to X/Ka observing starting from the current status of X/Ka and plans that are now taking shape. First X/Ka fringes were obtained in 2001 with the Deep Space Network. Future plans will be discussed including a proposed X/Ka-band upgrade to the VLBA. Lastly, we will consider the need for a period of overlap between S/X and X/Ka so that the long and rich history of astrometric and geodetic VLBI is not compromised.

  20. Standard Observing Bands: Is Now the Time to Replace S/X with X/Ka?

    NASA Technical Reports Server (NTRS)

    Jacobs, C. S.; Lanyi, G. E.; Naudet, C. J.

    2004-01-01

    In this paper we will argue that the VLBI community should be developing a road map to transition from S/X to simultaneous X and Ka-band (32 GHz) observations. There are both negative and positive reasons for planning such a transition. On the negative side, we will outline concerns that S-band observations may be headed toward obsolescence. On the positive side, we will refer to evidence that X/Ka has potential for providing a more stable reference frame than S/X. We will propose timetables for a transition to X/Ka observing starting from the current status of X/Ka and plans that are now taking shape. First X/Ka fringes were obtained in 2001 with the Deep Space Network. Future plans will be discussed including a proposed X/Ka-band upgrade to the VLBA. Lastly, we will consider the need for a period of overlap between S/X and X/Ka so that the long and rich history of astrometric and geodetic VLBI is not compromised.

  1. Studying NASA's Transition to Ka-Band Communications for Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Chelmins, David T.; Reinhart, Richard C.; Mortensen, Dale; Welch, Bryan; Downey, Joseph; Evans, Michael

    2014-01-01

    As the S-band spectrum becomes crowded, future space missions will need to consider moving command and telemetry services to Ka-band. NASA's Space Communications and Navigation (SCaN) Testbed provides a software-defined radio (SDR) platform that is capable of supporting investigation of this service transition. The testbed contains two S-band SDRs and one Ka-band SDR. Over the past year, SCaN Testbed has demonstrated Ka-band communications capabilities with NASAs Tracking and Data Relay Satellite System (TDRSS) using both open- and closed-loop antenna tracking profiles. A number of technical areas need to be addressed for successful transition to Ka-band. The smaller antenna beamwidth at Ka-band increases the criticality of antenna pointing, necessitating closed loop tracking algorithms and new techniques for received power estimation. Additionally, the antenna pointing routines require enhanced knowledge of spacecraft position and attitude for initial acquisition, versus an S-band antenna. Ka-band provides a number of technical advantages for bulk data transfer. Unlike at S-band, a larger bandwidth may be available for space missions, allowing increased data rates. The potential for high rate data transfer can also be extended for direct-to-ground links through use of variable or adaptive coding and modulation. Specific examples of Ka-band research from SCaN Testbeds first year of operation will be cited, such as communications link performance with TDRSS, and the effects of truss flexure on antenna pointing.

  2. Coeval ages of Australasian, Central American and Western Canadian tektites reveal multiple impacts 790 ka ago

    NASA Astrophysics Data System (ADS)

    Schwarz, Winfried H.; Trieloff, Mario; Bollinger, Klemens; Gantert, Niklas; Fernandes, Vera A.; Meyer, Hans-Peter; Povenmire, Hal; Jessberger, Elmar K.; Guglielmino, Massimo; Koeberl, Christian

    2016-04-01

    High resolution 40Ar-39Ar step heating dating of australites and indochinites, representing a large area of the Australasian strewn field, and more recently discovered tektite-like glasses from Central America (Belize) and Western Canada, were carried out. Precise plateau ages were obtained in all cases, yielding indistinguishable ages of 789 ± 9 ka for four australites, 783 ± 5 ka for four indochinites, 783 ± 17 ka for one Western Canadian and 769 ± 16 ka for one Belize impact glass. Concerning major elements and REEs, australites and the Western Canadian impact glass are indistinguishable. If the Western Canadian sample was transported by impact ejection and belongs to the Australasian strewn field, this implies extremely far ballistic transport of 9000 km distance, assuming a source crater in southern Asia. The distinct major element and REE composition of the Belize impact glass suggests formation in another separate impact event. We conclude that the Australasian/Western Canadian impact glasses formed 785 ± 7 ka ago in a single event and Belize impact glass in a separate event 769 ± 16 ka ago. The two impact events forming these two strewn fields occurred remarkably closely related in time, i.e., separated by <30 ka.

  3. KA-SB: from data integration to large scale reasoning

    PubMed Central

    Roldán-García, María del Mar; Navas-Delgado, Ismael; Kerzazi, Amine; Chniber, Othmane; Molina-Castro, Joaquín; Aldana-Montes, José F

    2009-01-01

    Background The analysis of information in the biological domain is usually focused on the analysis of data from single on-line data sources. Unfortunately, studying a biological process requires having access to disperse, heterogeneous, autonomous data sources. In this context, an analysis of the information is not possible without the integration of such data. Methods KA-SB is a querying and analysis system for final users based on combining a data integration solution with a reasoner. Thus, the tool has been created with a process divided into two steps: 1) KOMF, the Khaos Ontology-based Mediator Framework, is used to retrieve information from heterogeneous and distributed databases; 2) the integrated information is crystallized in a (persistent and high performance) reasoner (DBOWL). This information could be further analyzed later (by means of querying and reasoning). Results In this paper we present a novel system that combines the use of a mediation system with the reasoning capabilities of a large scale reasoner to provide a way of finding new knowledge and of analyzing the integrated information from different databases, which is retrieved as a set of ontology instances. This tool uses a graphical query interface to build user queries easily, which shows a graphical representation of the ontology and allows users o build queries by clicking on the ontology concepts. Conclusion These kinds of systems (based on KOMF) will provide users with very large amounts of information (interpreted as ontology instances once retrieved), which cannot be managed using traditional main memory-based reasoners. We propose a process for creating persistent and scalable knowledgebases from sets of OWL instances obtained by integrating heterogeneous data sources with KOMF. This process has been applied to develop a demo tool , which uses the BioPax Level 3 ontology as the integration schema, and integrates UNIPROT, KEGG, CHEBI, BRENDA and SABIORK databases. PMID:19796402

  4. Resilient FTS3 service at GridKa

    NASA Astrophysics Data System (ADS)

    Hartmann, T.; Bubeliene, J.; Hoeft, B.; Obholz, L.; Petzold, A.; Wisniewski, K.

    2015-12-01

    The FTS (File Transfer Service) service provides a transfer job scheduler to distribute and replicate vast amounts of data over the heterogeneous WLCG infrastructures. Compared to the channel model of the previous versions, the most recent version of FTS simplifies and improves the flexibility of the service while reducing the load to the service components. The improvements allow to handle a higher number of transfers with a single FTS3 setup. Covering now continent-wide transfers compared to the previous version, whose installations handled only transfers within specific clouds, a resilient system becomes even more necessary with the increased number of depending users. Having set up a FTS3 services at the German T1 site GridKa at KIT in Karlsruhe, we present our experiences on the preparations for a high-availability FTS3 service. Trying to avoid single points of failure, we rely on a database cluster as fault tolerant data back-end and the FTS3 service deployed on an own cluster setup to provide a resilient infrastructure for the users. With the database cluster providing a basic resilience for the data back-end, we ensure on the FTS3 service level a consistent and reliable database access through a proxy solution. On each FTS3 node a HAproxy instance is monitoring the integrity of each database node and distributes database queries over the whole cluster for load balancing during normal operations; in case of a broken database node, the proxy excludes it transparently to the local FTS3 service. The FTS3 service itself consists of a main and a backup instance, which takes over the identity of the main instance, i.e., IP, in case of an error using a CTDB (Cluster Trivial Database) infrastructure offering clients a consistent service.

  5. A 75 ka Stalagmite Paleoclimate Record from Northern Venezuela

    NASA Astrophysics Data System (ADS)

    Retrum, J. B.; Gonzalez, L. A.; Edwards, R.; Tincher, S. M.; Cheng, H.; Urbani, F.

    2011-12-01

    A stalagmite collected from Cueva Zarraga in the northern Venezuelan Andes was analyzed to determine local paleoclimatic history and help examine climate change in the Caribbean. Ages were determined by U/Th disequilibrium and the stalagmite shows a nearly complete record for ~ 75 ka. Two significant periods of non-deposition have been identified. The first period ranges between the Last Glacial Maximum at 19,820 ± 149 cal yr BP and a brief resumption of stalagmite growth at 15,409 ± 747 cal yr BP, likely representing the Bølling-Allerød interstadial. After the brief period of deposition, growth does not resume unil the Holocene at 10,408 ± 78 cal yr BP. Carbon and oxygen isotopes show a major depletion shift from the last glacial period to the Holocene, suggesting warmer and wetter conditions during the Holocene. The oxygen isotope depletion shift is also seen in the Cariaco Basin foraminifera record off the northern coast of Venezuela. While tempting to attribute δ13C depletion to decrease of the C4 plant contribution, there is no evidence that the area experience major vegetation changes. We attribute the δ13C depletion to enhanced recycling of soil CO2 resulting from canopy effects. Today, Cueva Zarraga is at the northern extent of the Inter-Tropical Convergence Zone (ITCZ). The cooler and drier conditions of the last glacial period suggest a southern displacement of the ITCZ. The close proximity of Cueva Zarraga to Cariaco Basin may allow for a high resolution tropical terrestrial and oceanic climatic response comparison.

  6. Drive alignment pays maintenance dividends

    SciTech Connect

    Fedder, R.

    2008-12-15

    Proper alignment of the motor and gear drive on conveying and processing equipment will result in longer bearing and coupling life, along with lower maintenance costs. Selecting an alignment free drive package instead of a traditional foot mounted drive and motor is a major advancement toward these goals. 4 photos.

  7. Drive Diagnostic Filter Wheel Control

    SciTech Connect

    Uhlich, D.

    2007-07-17

    DrD Filter Wheel Control is National Instrument's Labview software that drives a Drive Diagnostic filter wheel. The software can drive the filter wheel between each end limit, detect the positive and negative limit and each home position and post the stepper motot values to an Excel spreadsheet. The software can also be used to cycle the assembly between the end limits.

  8. Precipitation variability within the West Pacific Warm Pool over the past 120 ka: Evidence from the Davao Gulf, southern Philippines

    NASA Astrophysics Data System (ADS)

    Fraser, Nicholas; Kuhnt, Wolfgang; Holbourn, Ann; Bolliet, Timothé; Andersen, Nils; Blanz, Thomas; Beaufort, Luc

    2014-11-01

    Proxy records of hydrologic variability in the West Pacific Warm Pool (WPWP) have revealed wide-scale changes in past convective activity in response to orbital and suborbital climate forcings. However, attributing proxy responses to regional changes in WPWP hydrology versus local variations in precipitation requires independent records linking the terrestrial and marine realms. We present high-resolution stable isotope, UK'37 sea surface temperature, X-ray fluorescence (XRF) core scanning, and coccolithophore-derived paleoproductivity records covering the past 120 ka from International Marine Global Change (IMAGES) Program Core MD06-3075 (6°29'N, 125°50'E, water depth 1878 m), situated in the Davao Gulf on the southern side of Mindanao. XRF-derived log(Fe/Ca) records provide a robust proxy for runoff-driven sedimentary discharge from Mindanao, while past changes in local productivity are associated with variable freshwater runoff and stratification of the surface layer. Significant precessional-scale variability in sedimentary discharge occurred during marine isotope stage (MIS) 5, with peaks in discharge contemporaneous with Northern Hemisphere summer insolation minima. We attribute these changes to the latitudinal migration of the Intertropical Convergence Zone (ITCZ) over the WPWP together with variability in the strength of the Walker circulation acting on precessional timescales. Between 60 and 15 ka sedimentary discharge at Mindanao was muted, displaying little orbital- or millennial-scale variability, likely in response to weakened precessional insolation forcing and lower sea level driving increased subsidence of air masses over the exposed Sunda Shelf. These results highlight the high degree of local variability in the precipitation response to past climate changes in the WPWP.

  9. The pKa Distribution of Drugs: Application to Drug Discovery

    PubMed Central

    Manallack, David T.

    2007-01-01

    The acid-base dissociation constant (pKa) of a drug is a key physicochemical parameter influencing many biopharmaceutical characteristics. While this has been well established, the overall proportion of non-ionizable and ionizable compounds for drug-like substances is not well known. Even less well known is the overall distribution of acid and base pKa values. The current study has reviewed the literature with regard to both the proportion of ionizable substances and pKa distributions. Further to this a set of 582 drugs with associated pKa data was thoroughly examined to provide a representative set of observations. This was further enhanced by delineating the compounds into CNS and non-CNS drugs to investigate where differences exist. Interestingly, the distribution of pKa values for single acids differed remarkably between CNS and non-CNS substances with only one CNS compound having an acid pKa below 6.1. The distribution of basic substances in the CNS set also showed a marked cut off with no compounds having a pKa above 10.5. The pKa distributions of drugs are influenced by two main drivers. The first is related to the nature and frequency of occurrence of the functional groups that are commonly observed in pharmaceuticals and the typical range of pKa values they span. The other factor concerns the biological targets these compounds are designed to hit. For example, many CNS targets are based on seven transmembrane G protein-coupled receptors (7TM GPCR) which have a key aspartic acid residue known to interact with most ligands. As a consequence, amines are mostly present in the ligands that target 7TM GPCR’s and this influences the pKa profile of drugs containing basic groups. For larger screening collections of compounds, synthetic chemistry and the working practices of the chemists themselves can influence the proportion of ionizable compounds and consequent pKa distributions. The findings from this study expand on current wisdom in pKa research and have

  10. A Ka-band (32 GHz) beacon link experiment (KABLE) with Mars Observer

    NASA Technical Reports Server (NTRS)

    Riley, A. L.; Hansen, D. M.; Mileant, A.; Hartop, R. W.

    1987-01-01

    A proposal for a Ka-Band (32 GHz) Link Experiment (KABLE) with the Mars Observer mission was submitted to NASA. The experiment will rely on the fourth harmonic of the spacecraft X-band transmitter to generate a 33.6 GHz signal. The experiment will rely also on the Deep Space Network (DSN) receiving station equipped to simultaneously receive X- and Ka-band signals. The experiment will accurately measure the spacecraft-to-Earth telecommunication link performance at Ka-band and X-band (8.4 GHz).

  11. The Palaeoclimate of Wadi Shati, Libyan Sahara: the last 130 ka

    NASA Astrophysics Data System (ADS)

    Drake, Nick A.; Lem, Rachel E.; Armitage, Simon J.; White, Kevin H.; El-Hawat, Ahmed; Salem, Mustafa J.; Hounslow, Mark; Franke, Jan

    2014-05-01

    The Fezzan region of Libya forms a large closed basin that contains a wealth of ancient palaeolake and riverine sediments indicative of past humidity in the central Sahara. We have used remote sensing, DEM analysis and Ultra Ground Penetrating Radar to map these features and have dated them using OSL and radiocarbon methods. Results suggest humid conditions during both MIS 5 and the Holocene with larger lakes and more extensive river systems being present during MIS 5 suggestive of greater humidity at this time. A 4m core was collected from Holocene sediments of the largest lake found in the region (1200 km2 during MIS5 and 660 km2 during the Holocene). Core sediments were dated using OSL and analysed using XRF, Ion Chromatography, Laser Granulometry and chemical extractions for ostracods, diatoms, pollen and phytoliths. The base of the core is dominated by clays deposited in a perennial lake environment from 7.75 ka to 6.6 ka. Gypsum deposition started at about 6.5 ka indicating a more arid environment. Four clay layers are found amongst the gypsum from 6.3 to 6.25 ka, 6.2 to 6.1, 6.0 to 5.8 and 5.7-5.6 ka suggests that aridification was not a sudden event, but consisted of a series of arid/humid oscillations before the lake finally desiccated just before 5 ka. No pollen, diatoms or ostracods are preserved in the sediments but phytoliths were present. Both tree and grass phytoliths were found in lower parts of the core, suggesting a wooded savannah environment from 7.75 to about 7 ka. Trees decline and grass increases up the core, signifying an increasingly arid environment. By the time the first gypsum bed is deposited at about 6.5 ka trees have disappeared and grass dominates. These results do not support the hypothesis of a sudden aridification of the Sahara at 4.9 ka and instead suggest that in the Fezzan region a gradual aridification had started by 7.75 ka and that the climate oscillated during the lake desiccation that started at 6.5 ka and was complete by

  12. A Novel Ku-Band/Ka-Band and Ka-Band/E-Band Multimode Waveguide Couplers for Power Measurement of Traveling-Wave Tube Amplifier Harmonic Frequencies

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee N.

    2015-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler, fabricated from two dissimilar frequency band waveguides, is capable of isolating power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT) amplifier. Test results from proof-of-concept demonstrations are presented for a Ku-band/Ka-band MDC and a Ka-band/E-band MDC. In addition to power measurements at harmonic frequencies, a potential application of the MDC is in the design of a satellite borne beacon source for atmospheric propagation studies at millimeter-wave (mm-wave) frequencies (Ka-band and E-band).

  13. Offset Compound Gear Drive

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  14. Modular droplet actuator drive

    NASA Technical Reports Server (NTRS)

    Pollack, Michael G. (Inventor); Paik, Philip (Inventor)

    2011-01-01

    A droplet actuator drive including a detection apparatus for sensing a property of a droplet on a droplet actuator; circuitry for controlling the detection apparatus electronically coupled to the detection apparatus; a droplet actuator cartridge connector arranged so that when a droplet actuator cartridge electronically is coupled thereto: the droplet actuator cartridge is aligned with the detection apparatus; and the detection apparatus can sense the property of the droplet on a droplet actuator; circuitry for controlling a droplet actuator coupled to the droplet actuator connector; and the droplet actuator circuitry may be coupled to a processor.

  15. Robot Arm with Tendon Connector Plate and Linear Actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Bridgwater, Lyndon (Inventor); Nguyen, Vienny (Inventor); Millerman, Alexander (Inventor)

    2014-01-01

    A robotic system includes a tendon-driven end effector, a linear actuator, a flexible tendon, and a plate assembly. The linear actuator assembly has a servo motor and a drive mechanism, the latter of which translates linearly with respect to a drive axis of the servo motor in response to output torque from the servo motor. The tendon connects to the end effector and drive mechanism. The plate assembly is disposed between the linear actuator assembly and the tendon-driven end effector and includes first and second plates. The first plate has a first side that defines a boss with a center opening. The second plate defines an accurate through-slot having tendon guide channels. The first plate defines a through passage for the tendon between the center opening and a second side of the first plate. A looped end of the flexible tendon is received within the tendon guide channels.

  16. Relative toxicity of para-substituted phenols: log K/sub ow/ and pKa-dependent structure-activity relationships

    SciTech Connect

    Schultz, T.W.

    1987-06-01

    The toxic response of the majority of industrial chemicals which are nonreactive and non -ionic can be quantitatively modeled by the 1-octanol/water partition coefficient (K/sub ow/) in a linear fashion following a log-log transformation of the data. The toxicity of phenols, however does not model by these same quantitative structure-activity relationships (QSAR). Earlier studies have shown that the addition of pKa as a second molecular descriptor improves the predictive capability of log K/sub ow/ QSAR. The predicted toxicity of phenol derivatives, which ionize poorly under the test conditions, is not significantly altered by using models in which pKa is not included. In an effort to systematically explore the extent to which such log K/sub ow/ and, log K/sub ow/ and pKa-dependent QSAR can be used to predict the biological activity of phenols, the first in a series of investigations was conducted using the rapid and inexpensive Tetrahymena population growth impairment assay to determine relative toxicity of 30 para-substituted derivatives.

  17. Oil well pump driving unit

    SciTech Connect

    Gilbertson, T.A.

    1984-02-21

    An oil well pump driving unit with a horizontally disposed hydraulic cylinder having a cylinder rod coupled to a drive rope extending into a pumping tee-stuffing box arrangement for driving the sucker rod string leading to a conventional oil well reciprocating pump. The drive rope extends over a first rotating sheave mounted near the wellhead and passes over a second rotating sheave mounted on a carriage which traverses a carriage channel in a draw works on which the hydraulic cylinder is mounted. A hydraulic drive/control system utilizing limit switches on the draw works provides control over the stroke position, the stroke length, and the stroke rate.

  18. Advances in traction drive technology

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Anderson, N. E.; Rohn, D. A.

    1983-01-01

    Traction drives are traced from early uses as main transmissions in automobiles at the turn of the century to modern, high-powered traction drives capable of transmitting hundreds of horsepower. Recent advances in technology are described which enable today's traction drive to be a serious candidate for off-highway vehicles and helicopter applications. Improvements in materials, traction fluids, design techniques, power loss and life prediction methods will be highlighted. Performance characteristics of the Nasvytis fixed-ratio drive are given. Promising future drive applications, such as helicopter main transmissions and servo-control positioning mechanisms are also addressed.

  19. Rf-driver linear colliders

    SciTech Connect

    Wilson, P.B.

    1987-05-01

    The next generation of linear collider after the SLC (Stanford Linear Collider) will probably have an energy in the range 300 GeV-1 TeV per linac. A number of exotic accelerating schemes, such as laser and plasma acceleration, have been proposed for linear colliders of the far future. However, the technology which is most mature and which could lead to a collider in the above energy range in the relatively near future is the rf-driven linac, in which externally produced rf is fed into a more or less conventional metallic accelerating structure. Two basic technologies have been proposed for producing the required high peak rf power: discrete microwave power sources, and various two-beam acceleration schemes in which the rf is produced by a high current driving beam running parallel to the main accelerator. The current status of experimental and analytic work on both the discrete source and the two-beam methods for producing rf is discussed. The implications of beam-beam related effects (luminosity, disruption and beamstrahlung) for the design of rf-driven colliders are also considered.

  20. Superconducting cavity driving with FPGA controller

    NASA Astrophysics Data System (ADS)

    Czarski, Tomasz; Koprek, Waldemar; Poźniak, Krzysztof T.; Romaniuk, Ryszard S.; Simrock, Stefan; Brandt, Alexander; Chase, Brian; Carcagno, Ruben; Cancelo, Gustavo; Koeth, Timothy W.

    2006-12-01

    A digital control of superconducting cavities for a linear accelerator is presented. FPGA-based controller, supported by Matlab system, was applied. Electrical model of a resonator was used for design of a control system. Calibration of the signal path is considered. Identification of cavity parameters has been carried out for adaptive control algorithm. Feed-forward and feedback modes were applied in operating the cavities. Required performance has been achieved; i.e. driving on resonance during filling and field stabilization during flattop time, while keeping reasonable level of the power consumption. Representative results of the experiments are presented for different levels of the cavity field gradient.

  1. Electronic Non-Contacting Linear Position Measuring System

    DOEpatents

    Post, Richard F.

    2005-06-14

    A non-contacting linear position location system employs a special transmission line to encode and transmit magnetic signals to a receiver on the object whose position is to be measured. The invention is useful as a non-contact linear locator of moving objects, e.g., to determine the location of a magnetic-levitation train for the operation of the linear-synchronous motor drive system.

  2. Turbulent current drive

    NASA Astrophysics Data System (ADS)

    Garbet, X.; Esteve, D.; Sarazin, Y.; Dif-Pradalier, G.; Ghendrih, P.; Grandgirard, V.; Latu, G.; Smolyakov, A.

    2014-11-01

    The Ohm's law is modified when turbulent processes are accounted for. Besides an hyper-resistivity, already well known, pinch terms appear in the electron momentum flux. Moreover it appears that turbulence is responsible for a source term in the Ohm's law, called here turbulent current drive. Two terms contribute to this source. The first term is a residual stress in the momentum flux, while the second contribution is an electro-motive force. A non zero average parallel wave number is needed to get a finite source term. Hence a symmetry breaking mechanism must be invoked, as for ion momentum transport. E × B shear flows and turbulence intensity gradients are shown to provide similar contributions. Moreover this source term has to compete with the collision friction term (resistivity). The effect is found to be significant for a large scale turbulence in spite of an unfavorable scaling with the ratio of the electron to ion mass. Turbulent current drive appears to be a weak effect in the plasma core, but could be substantial in the plasma edge where it may produce up to 10 % of the local current density.

  3. Polar drive on OMEGA

    NASA Astrophysics Data System (ADS)

    Radha, P. B.; Marshall, F. J.; Boehly, T. R.; Collins, T. J. B.; Craxton, R. S.; Edgell, D.; Epstein, R.; Frenje, J.; Goncharov, V. N.; Marozas, J. A.; McCrory, R. L.; McKenty, P. W.; Meyerhofer, D. D.; Petrasso, R. D.; Sangster, T. C.; Shvydky, A.; Skupsky, S.

    2013-11-01

    High-convergence polar-drive experiments are being conducted on OMEGA [T. R. Boehly et al., Opt. Commum. 133, 495 (1997)] using triple-picket laser pulses. The goal of OMEGA experiments is to validate modeling of oblique laser deposition, heat conduction in the presence of nonradial thermal gradients in the corona, and implosion energetics in the presence of laser-plasma interactions such as crossed-beam energy transfer. Simulated shock velocities near the equator, where the beams are obliquely incident, are within 5% of experimentally inferred values in warm plastic shells, well within the required accuracy for ignition. High, near-one-dimensional areal density is obtained in warm-plastic-shell implosions. Simulated backlit images of the compressing core are in good agreement with measured images. Outstanding questions that will be addressed in the future relate to the role of cross-beam transfer in polar drive irradiation and increasing the energy coupled into the target by decreasing beam obliquity.

  4. Glaucoma and Driving: On-Road Driving Characteristics

    PubMed Central

    Wood, Joanne M.; Black, Alex A.; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia

    2016-01-01

    Purpose To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Methods Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Results Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Conclusions Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness. PMID:27472221

  5. Advances in Ka-Band Communication System for CubeSats and SmallSats

    NASA Technical Reports Server (NTRS)

    Kegege, Obadiah; Wong, Yen F.; Altunc, Serhat

    2016-01-01

    A study was performed that evaluated the feasibility of Ka-band communication system to provide CubeSat/SmallSat high rate science data downlink with ground antennas ranging from the small portable 1.2m/2.4m to apertures 5.4M, 7.3M, 11M, and 18M, for Low Earth Orbit (LEO) to Lunar CubeSat missions. This study included link analysis to determine the data rate requirement, based on the current TRL of Ka-band flight hardware and ground support infrastructure. Recent advances in Ka-band transceivers and antennas, options of portable ground stations, and various coverage distances were included in the analysis. The link/coverage analysis results show that Cubesat/Smallsat missions communication requirements including frequencies and data rates can be met by utilizing Near Earth Network (NEN) Ka-band support with 2 W and high gain (>6 dBi) antennas.

  6. Design and Validation of High Date Rate Ka-Band Software Defined Radio for Small Satellite

    NASA Technical Reports Server (NTRS)

    Xia, Tian

    2016-01-01

    The Design and Validation of High Date Rate Ka- Band Software Defined Radio for Small Satellite project will develop a novel Ka-band software defined radio (SDR) that is capable of establishing high data rate inter-satellite links with a throughput of 500 megabits per second (Mb/s) and providing millimeter ranging precision. The system will be designed to operate with high performance and reliability that is robust against various interference effects and network anomalies. The Ka-band radio resulting from this work will improve upon state of the art Ka-band radios in terms of dimensional size, mass and power dissipation, which limit their use in small satellites.

  7. Design of Input Coupler and Output Window for Ka-Band Gyro-TWT

    NASA Astrophysics Data System (ADS)

    Alaria, M. K.; Singh, Khushbu; Choyal, Y.; Sinha, A. K.

    2013-10-01

    The design of input coupler with loaded interaction structure for Ka-band gyro traveling wave tube (gyro-TWT) has been carried out using Ansoft HFSS to operate in the TE11 mode. The return loss (S11) and transmission loss (S21) of the Ka-band gyro-TWT input coupler have been found -27.3 and -0.05 dB respectively. The design of output window for Ka-band gyro-TWT has been carried out using CST microwave studio. In this paper thermal analysis of the input coupler for Ka-band gyro-TWT has also been carried out using ANSYS software. In the simulation results, the temperature on the ceramic disc of window does not exceed 80 °C and found in safe limit. The optimized design of input and output window for gyro-TWT allows low heat loads in the ceramic and consequently low temperature increase.

  8. Ka-Band Atmospheric Noise Temperature Measurements Using a 34-Meter Beam-Waveguide Antenna

    NASA Technical Reports Server (NTRS)

    Morabito, D.; Clauss, B.; Speranza, M.

    1997-01-01

    (viewgraphs) NASA's Deep space missions have used 960 MHz, 2.3 GHz, and 8.4 GHz for spacecraft communication downlinks. Ka-band (32 GHz) is being considered as a downlink frequency for future flight projects.

  9. Experiments for Ka-band mobile applications: The ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Estabrook, Polly; Dessouky, Khaled; Jedrey, Thomas

    1990-01-01

    To explore the potential of Ka-band to support mobile satellite services, the Jet Propulsion Laboratory (JPL) has initiated the design and development of a Ka-band land-mobile terminal to be used with the Advanced Communications Technology Satellite (ACTS). The planned experimental setup with ACTS is described. Brief functional descriptions of the mobile and fixed terminals are provided. The inputs required from the propagation community to support the design activities and the planned experiments are also discussed.

  10. Evaluation of Methods for the Calculation of the pKa of Cysteine Residues in Proteins.

    PubMed

    Awoonor-Williams, Ernest; Rowley, Christopher N

    2016-09-13

    Methods for the calculation of the pKa ionizable amino acids are valuable tools for understanding pH-dependent properties of proteins. Cysteine is unique among the amino acids because of the chemical reactivity of its thiol group (S-H), which plays an instrumental role in several biochemical and regulatory functions. The acidity of noncatalytic cysteine residues is a factor in their susceptibility to chemical modification. Despite the plethora of existing pKa computing methods, no definitive protocol exists for accurately calculating the pKa's of cysteine residues in proteins. A cysteine pKa test set was developed, which is comprised of 18 cysteine residues in 12 proteins where the pKa's have been determined experimentally and an experimental structure is available. The pKa's of these residues were calculated using three methods that use an implicit solvent model (H++, MCCE, and PROPKA) and an all-atom replica-exchange thermodynamic integration approach with the CHARMM36 and AMBER ff99SB-ILDNP force fields. The models that use implicit solvation methods were generally unreliable in predicting cysteine residue pKa's, with RMSDs between 3.41 and 4.72 pKa units. On average, the explicit solvent methods performed better than the implicit solvent methods. RMSD values of 2.40 and 3.20 were obtained for simulations with the CHARMM36 and AMBER ff99SB-ILDNP force fields, respectively. Further development of these methods is necessary because the performance of the best method is similar to that of the null-model (RMSD = 2.74) and these differences in RMSD are of limited statistical significance given the small size of our test set. PMID:27541839

  11. NASA's Evolution to Ka-Band Space Communications for Near-Earth Spacecraft

    NASA Technical Reports Server (NTRS)

    McCarthy, Kevin; Stocklin, Frank; Geldzahler, Barry; Friedman, Daniel; Celeste, Peter

    2010-01-01

    This slide presentation reviews the exploration of NASA using a Ka-band system for spacecraft communications in Near-Earth orbits. The reasons for changing to Ka-band are the higher data rates, and the current (X-band spectrum) is becoming crowded. This will require some modification to the current ground station antennas systems. The results of a Request for Information (RFI) are discussed, and the recommended solution is reviewed.

  12. Complete Genome Sequence of the Thermophilic, Piezophilic, Heterotrophic Bacterium Marinitoga piezophila KA3

    SciTech Connect

    Lucas, Susan; Han, James; Lapidus, Alla L.; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Sam; Peters, Lin; Mikhailova, Natalia; Teshima, Hazuki; Detter, J. Chris; Han, Cliff; Tapia, Roxanne; Land, Miriam L; Hauser, Loren John; Kyrpides, Nikos C; Ivanova, N; Pagani, Ioanna; Vannier, Pauline; Oger, Phil; Bartlett, Douglas; Noll, Kenneth M; Woyke, Tanja; Jebbar, Mohamed

    2012-01-01

    Marinitoga piezophila KA3 is a thermophilic, anaerobic, chemoorganotrophic, sulfur-reducing bacterium isolated from the Grandbonum deep-sea hydrothermal vent site at the East Pacific Rise (13 degrees N, 2,630-m depth). The genome of M. piezophila KA3 comprises a 2,231,407-bp circular chromosome and a 13,386-bp circular plasmid. This genome was sequenced within Department of Energy Joint Genome Institute CSP 2010.

  13. An abrupt and prominent climatic reversal at 9.2 ka in the northeastern North America

    NASA Astrophysics Data System (ADS)

    Hou, J.; Huang, Y.; Shuman, B. N.; Oswald, W.; Foster, D. R.

    2008-12-01

    Continental climate during the early Holocene (from 10 to 7 ka) is characterized by multiple abrupt climatic reversals such as the well-known 8.2 ka event that has been observed worldwide and attributed to the terminal collapse of the Laurentide Ice Sheet (LIS) in the North American continent. However, many episodes of meltwater releases occurred prior to the final collapse of LIS, their impact on the continental climate is much less understood. We present in this paper decadal-scale hydrogen isotopic records of aquatic and terrestrial plant biomarkers from Blood Pond, Massachusetts during the early Holocene. Our isotopic records infer a cooling of 3~4 degree between 9.3 and 9.1 ka against the millennial scale climate background, mainly induced by changes in precipitation seasonality. In comparison, the 8.2 ka event displays smaller amplitude of temperature cooling of 1~2 degree at our southern New England site. We interpret our observed climatic reversal at ~ 9.2 ka as representing increased proportion of winter precipitation in conjunction with a drier and cooler summer, triggered by slowdown in thermohaline circulation as a result of freshwater release from the proglacial lakes. We attribute the difference in climate response at 8.2 ka and 9.2 ka events to the configuration of LIS, with 9.2 ka LIS having a much stronger blocking effect on the moisture from the Gulf of Mexico during the summer. Our data suggest that the seasonality of the precipitation at the southern New England was highly sensitive to meltwater releases, especially prior to the final collapse of the LIS.

  14. A View from the Cocoon--Space Categorization in the Korean Verb [na-ka-ta].

    ERIC Educational Resources Information Center

    Kim, Alan Hyun-Oak

    1996-01-01

    Analysis of the Korean verb "na-ka-ta" ("to get out, exit") focuses on why an expression such as "kyengkicang-ey na-ka-ta" ("someone goes out/in to the sports arena") is acceptable only in the context that the person's entering the arena is for the purpose of a contest, while it becomes semantically anomalous if intended to express the situation…

  15. High average power linear induction accelerator development

    SciTech Connect

    Bayless, J.R.; Adler, R.J.

    1987-07-01

    There is increasing interest in linear induction accelerators (LIAs) for applications including free electron lasers, high power microwave generators and other types of radiation sources. Lawrence Livermore National Laboratory has developed LIA technology in combination with magnetic pulse compression techniques to achieve very impressive performance levels. In this paper we will briefly discuss the LIA concept and describe our development program. Our goals are to improve the reliability and reduce the cost of LIA systems. An accelerator is presently under construction to demonstrate these improvements at an energy of 1.6 MeV in 2 kA, 65 ns beam pulses at an average beam power of approximately 30 kW. The unique features of this system are a low cost accelerator design and an SCR-switched, magnetically compressed, pulse power system. 4 refs., 7 figs.

  16. High-resolution sea surface reconstructions off Cape Hatteras over the last 10 ka

    NASA Astrophysics Data System (ADS)

    CléRoux, Caroline; Debret, Maxime; Cortijo, Elsa; Duplessy, Jean-Claude; Dewilde, Fabien; Reijmer, John; Massei, Nicolas

    2012-03-01

    This study presents high-resolution foraminiferal-based sea surface temperature, sea surface salinity and upper water column stratification reconstructions off Cape Hatteras, a region sensitive to atmospheric and thermohaline circulation changes associated with the Gulf Stream. We focus on the last 10,000 years (10 ka) to study the surface hydrology changes under our current climate conditions and discuss the centennial to millennial time scale variability. We observed opposite evolutions between the conditions off Cape Hatteras and those south of Iceland, known today for the North Atlantic Oscillation pattern. We interpret the temperature and salinity changes in both regions as co-variation of activities of the subtropical and subpolar gyres. Around 8.3 ka and 5.2-3.5 ka, positive salinity anomalies are reconstructed off Cape Hatteras. We demonstrate, for the 5.2-3.5 ka period, that the salinity increase was caused by the cessation of the low salinity surface flow coming from the north. A northward displacement of the Gulf Stream, blocking the southbound low-salinity flow, concomitant to a reduced Meridional Overturning Circulation is the most likely scenario. Finally, wavelet transform analysis revealed a 1000-year period pacing the δ18O signal over the early Holocene. This 1000-year frequency band is significantly coherent with the 1000-year frequency band of Total Solar Irradiance (TSI) between 9.5 ka and 7 ka and both signals are in phase over the rest of the studied period.

  17. Pre-Flight Testing and Performance of a Ka-Band Software Defined Radio

    NASA Technical Reports Server (NTRS)

    Downey, Joseph A.; Reinhart, Richard C.; Kacpura, Thomas

    2012-01-01

    National Aeronautics and Space Administration (NASA) has developed a space-qualified, reprogrammable, Ka-band Software Defined Radio (SDR) to be utilized as part of an on-orbit, reconfigurable testbed. The testbed will operate on the truss of the International Space Station beginning in late 2012. Three unique SDRs comprise the testbed, and each radio is compliant to the Space Telecommunications Radio System (STRS) Architecture Standard. The testbed provides NASA, industry, other Government agencies, and academic partners the opportunity to develop communications, navigation, and networking applications in the laboratory and space environment, while at the same time advancing SDR technology, reducing risk, and enabling future mission capability. Designed and built by Harris Corporation, the Ka-band SDR is NASA's first space-qualified Ka-band SDR transceiver. The Harris SDR will also mark the first NASA user of the Ka-band capabilities of the Tracking Data and Relay Satellite System (TDRSS) for on-orbit operations. This paper describes the testbed's Ka-band System, including the SDR, travelling wave tube amplifier (TWTA), and antenna system. The reconfigurable aspects of the system enabled by SDR technology are discussed and the Ka-band system performance is presented as measured during extensive pre-flight testing.

  18. pKa determination by ¹H NMR spectroscopy - an old methodology revisited.

    PubMed

    Bezençon, Jacqueline; Wittwer, Matthias B; Cutting, Brian; Smieško, Martin; Wagner, Bjoern; Kansy, Manfred; Ernst, Beat

    2014-05-01

    pKa values of acids and protonated bases have an essential impact on organic synthesis, medicinal chemistry, and material and food sciences. In drug discovery and development, they are of utmost importance for the prediction of pharmacokinetic and pharmacodynamic properties. To date, various methods for the determination of pKa values are available, including UV-spectroscopic, potentiometric, and capillary electrophoretic techniques. An additional option is provided by nuclear magnetic resonance (NMR) spectroscopy. The underlying principle is the alteration of chemical shifts of NMR-active nuclei (e.g., (13)C and (1)H) depending on the protonation state of adjacent acidic or basic sites. When these chemical shifts are plotted against the pH, the inflection point of the resulting sigmoidal curve defines the pKa value. Although pKa determinations by (1)H NMR spectroscopy are reported for numerous cases, the potential of this approach is not yet fully evaluated. We therefore revisited this method with a diverse set of test compounds covering a broad range of pKa values (pKa 0.9-13.8) and made a comparison with four commonly used approaches. The methodology revealed excellent correlations (R(2)=0.99 and 0.97) with electropotentiometric and UV spectroscopic methods. Moreover, the comparison with in silico results (Epik and Marvin) also showed high correlations (R(2)=0.92 and 0.94), further confirming the reliability and utility of this approach. PMID:24462329

  19. Earth as diode: monsoon source of the orbital ~100 ka climate cycle

    NASA Astrophysics Data System (ADS)

    Anderson, R. Y.

    2010-08-01

    A potential source for Earth's enigmatic ~100 ka climate cycle, which is found in many ancient geological records at low latitudes and also in the pacing of glaciation during the late Pleistocene, is traced to a climatic rectifying process inherent in the monsoon. Seasonal information needed to identify the rectifying mechanism is preserved within varves of a continuous, 200 ka recording of annual maximum surface temperature (Tmax) from the equator of Western Pangea. Specific seasonal reactions recorded in varves show how the monsoon reacted to seasonal differences in insolation at equinox to produce a 11.7 ka semi-precession cycle in Tmax. At solstice, anti-phasing of insolation in the Northern and Southern Hemispheres, intensified and focused by a highly asymmetric Pangea relative to the equator, produced a strong equatorial maritime monsoon that performed a nonlinear rectifying function similar to that of a simple rectifying diode. Expressed in the resulting varve series are substantial cycles in Tmax of 100 ka, 23.4 ka, and 11.7 ka. Importantly, any external or internal forcing of the tropical (monsoon) climate system at higher-than-orbital frequencies (e.g. solar, ENSO) should also be amplified at Milankovitch frequencies by the monsoon.

  20. Design research on the conductor of 10 kA class HTS DC power cable

    NASA Astrophysics Data System (ADS)

    Zhang, Dong; Dai, Shaotao; Zhang, Fengyuan; Huang, Tianbin; Wang, Yinshun; Lin, Yubao; Teng, Yuping; Zhang, Guomin; Xiao, Liye; Lin, Liangzhen

    2012-12-01

    High temperature superconducting (HTS) DC power cable shows a wide application prospect in the field of power transmission for its nearly lossless and rather high capacity. A 360 m/10 kA HTS DC power cable system, which connects the rectifier output of a substation with the bus bar of an electrolytic aluminium cell, will be put into operation at Henan Zhongfu Industrial Co., Ltd. As one of the items in this project, a 5 m/10 kA HTS DC power cable was developed, which is used to investigate the conductor design, fabrication, current-carrying capacity and stability of the 360 m/10 kA HTS power cable. The HTS DC power cable core consists of five conductor layers wound with spliced Bi-2223 wires with the length of 600 m. The cable core has five layers and 23 conductors in each layer with the outer diameter of 45.42 mm. The superconducting power cable is fabricated and tested. The critical current is about 14.3 kA at 77 K. The superconducting power cable is charged to 10 kA with rate of 10 A/s and operates at steady-state for 30 min. In this paper, the 10 kA HTS DC power cable design, fabrication and test are presented. The experimental research of the performance of spliced superconducting wire and charging, steady-state operating performance of the cable was carried out.

  1. Improving Cry8Ka toxin activity towards the cotton boll weevil (Anthonomus grandis)

    PubMed Central

    2011-01-01

    Background The cotton boll weevil (Anthonomus grandis) is a serious insect-pest in the Americas, particularly in Brazil. The use of chemical or biological insect control is not effective against the cotton boll weevil because of its endophytic life style. Therefore, the use of biotechnological tools to produce insect-resistant transgenic plants represents an important strategy to reduce the damage to cotton plants caused by the boll weevil. The present study focuses on the identification of novel molecules that show improved toxicity against the cotton boll weevil. In vitro directed molecular evolution through DNA shuffling and phage display screening was applied to enhance the insecticidal activity of variants of the Cry8Ka1 protein of Bacillus thuringiensis. Results Bioassays carried out with A. grandis larvae revealed that the LC50 of the screened mutant Cry8Ka5 toxin was 3.15-fold higher than the wild-type Cry8Ka1 toxin. Homology modelling of Cry8Ka1 and the Cry8Ka5 mutant suggested that both proteins retained the typical three-domain Cry family structure. The mutated residues were located mostly in loops and appeared unlikely to interfere with molecular stability. Conclusions The improved toxicity of the Cry8Ka5 mutant obtained in this study will allow the generation of a transgenic cotton event with improved potential to control A. grandis. PMID:21906288

  2. The GridKa Tier-1 Computing Center within the ALICE Grid Framework

    NASA Astrophysics Data System (ADS)

    Park, WooJin J.; Christopher, Jung; Heiss, Andreas; Petzold, Andreas; Schwarz, Kilian

    2014-06-01

    The GridKa computing center, hosted by Steinbuch Centre for Computing at the Karlsruhe Institute for Technology (KIT) in Germany, is serving as the largest Tier-1 center used by the ALICE collaboration at the LHC. In 2013, GridKa provides 30k HEPSPEC06, 2.7 PB of disk space, and 5.25 PB of tape storage to ALICE. The 10Gbit/s network connections from GridKa to CERN, several Tier-1 centers and the general purpose network are used by ALICE intensively. In 2012 a total amount of ~1 PB was transferred to and from GridKa. As Grid framework, AliEn (ALICE Environment) is being used to access the resources, and various monitoring tools including the MonALISA (MONitoring Agent using a Large Integrated Services Architecture) are always running to alert in case of any problem. GridKa on-call engineers provide 24/7 support to guarantee minimal loss of availability of computing and storage resources in case of hardware or software problems. We introduce the GridKa Tier-1 center from the viewpoint of ALICE services.

  3. A Ka-Band Celestial Reference Frame with Applications to Deep Space Navigation

    NASA Technical Reports Server (NTRS)

    Jacobs, Christopher S.; Clark, J. Eric; Garcia-Miro, Cristina; Horiuchi, Shinji; Sotuela, Ioana

    2011-01-01

    The Ka-band radio spectrum is now being used for a wide variety of applications. This paper highlights the use of Ka-band as a frequency for precise deep space navigation based on a set of reference beacons provided by extragalactic quasars which emit broadband noise at Ka-band. This quasar-based celestial reference frame is constructed using X/Ka-band (8.4/32 GHz) from fifty-five 24-hour sessions with the Deep Space Network antennas in California, Australia, and Spain. We report on observations which have detected 464 sources covering the full 24 hours of Right Ascension and declinations down to -45 deg. Comparison of this X/Ka-band frame to the international standard S/X-band (2.3/8.4 GHz) ICRF2 shows wRMS agreement of approximately 200 micro-arcsec in alpha cos(delta) and approximately 300 micro-arcsec in delta. There is evidence for systematic errors at the 100 micro-arcsec level. Known errors include limited SNR, lack of instrumental phase calibration, tropospheric refraction mis-modeling, and limited southern geometry. The motivation for extending the celestial reference frame to frequencies above 8 GHz is to access more compact source morphology for improved frame stability and to support spacecraft navigation for Ka-band based NASA missions.

  4. Progress in the prediction of pKa values in proteins

    SciTech Connect

    Alexov, Emil; Mehler, Ernest L.; Baker, Nathan A.; Baptista, Antonio; Huang, Yong; Milletti, Francesca; Nielsen, Jens E.; Farrell, Damien; Carstensen, Tommy; Olsson, Mats H.; Shen, Jana K.; Warwicker, Jim; Williams, Sarah; Word, J Michael

    2011-12-15

    The pKa-cooperative aims to provide a forum for experimental and theoretical researchers interested in protein pKa values and protein electrostatics in general. The first round of the pKa -cooperative, which challenged computational labs to carry out blind predictions against pKas experimentally determined in the laboratory of Bertrand Garcia-Moreno, was completed and results discussed at the Telluride meeting (July 6-10, 2009). This paper serves as an introduction to the reports submitted by the blind prediction participants that will be published in a special issue of PROTEINS: Structure, Function and Bioinformatics. Here we briefly outline existing approaches for pKa calculations, emphasizing methods that were used by the participants in calculating the blind pKa values in the first round of the cooperative. We then point out some of the difficulties encountered by the participating groups in making their blind predictions, and finally try to provide some insights for future developments aimed at improving the accuracy of pKa calculations.

  5. Isodesmic reaction for accurate theoretical pKa calculations of amino acids and peptides.

    PubMed

    Sastre, S; Casasnovas, R; Muñoz, F; Frau, J

    2016-04-28

    Theoretical and quantitative prediction of pKa values at low computational cost is a current challenge in computational chemistry. We report that the isodesmic reaction scheme provides semi-quantitative predictions (i.e. mean absolute errors of 0.5-1.0 pKa unit) for the pKa1 (α-carboxyl), pKa2 (α-amino) and pKa3 (sidechain groups) of a broad set of amino acids and peptides. This method fills the gaps of thermodynamic cycles for the computational pKa calculation of molecules that are unstable in the gas phase or undergo proton transfer reactions or large conformational changes from solution to the gas phase. We also report the key criteria to choose a reference species to make accurate predictions. This method is computationally inexpensive and makes use of standard density functional theory (DFT) and continuum solvent models. It is also conceptually simple and easy to use for researchers not specialized in theoretical chemistry methods. PMID:27052591

  6. The SPARC linear accelerator based terahertz source

    SciTech Connect

    Chiadroni, E.; Bacci, A.; Bellaveglia, M.; Boscolo, M.; Castellano, M.; Cultrera, L.; Di Pirro, G.; Ferrario, M.; Ficcadenti, L.; Filippetto, D.; Gatti, G.; Pace, E.; Rossi, A. R.; Vaccarezza, C.; Catani, L.; Cianchi, A.; Marchetti, B.; Mostacci, A.; Palumbo, L.; Ronsivalle, C.; and others

    2013-03-04

    Ultra-short electron beams, produced through the velocity bunching compression technique, are used to drive the SPARC linear accelerator based source, which relies on the emission of coherent transition radiation in the terahertz range. This paper reports on the main features of this radiation, as terahertz source, with spectral coverage up to 5 THz and pulse duration down to 200 fs, with an energy per pulse of the order of several micro-joule, and as electron beam longitudinal diagnostics.

  7. Dimensions of driving anger and their relationships with aberrant driving.

    PubMed

    Zhang, Tingru; Chan, Alan H S; Zhang, Wei

    2015-08-01

    The purpose of this study was to investigate the relationship between driving anger and aberrant driving behaviours. An internet-based questionnaire survey was administered to a sample of Chinese drivers, with driving anger measured by a 14-item short Driving Anger Scale (DAS) and the aberrant driving behaviours measured by a 23-item Driver Behaviour Questionnaire (DBQ). The results of Confirmatory Factor Analysis demonstrated that the three-factor model (hostile gesture, arrival-blocking and safety-blocking) of the DAS fitted the driving anger data well. The Exploratory Factor Analysis on DBQ data differentiated four types of aberrant driving, viz. emotional violation, error, deliberate violation and maintaining progress violation. For the anger-aberration relation, it was found that only "arrival-blocking" anger was a significant positive predictor for all four types of aberrant driving behaviours. The "safety-blocking" anger revealed a negative impact on deliberate violations, a finding different from previously established positive anger-aberration relation. These results suggest that drivers with different patterns of driving anger would show different behavioural tendencies and as a result intervention strategies may be differentially effective for drivers of different profiles.

  8. Automatism and driving offences.

    PubMed

    Rumbold, John

    2013-10-01

    Automatism is a rarely used defence, but it is particularly used for driving offences because many are strict liability offences. Medical evidence is almost always crucial to argue the defence, and it is important to understand the bars that limit the use of automatism so that the important medical issues can be identified. The issue of prior fault is an important public safeguard to ensure that reasonable precautions are taken to prevent accidents. The total loss of control definition is more problematic, especially with disorders of more gradual onset like hypoglycaemic episodes. In these cases the alternative of 'effective loss of control' would be fairer. This article explores several cases, how the criteria were applied to each, and the types of medical assessment required. PMID:24112330

  9. Automatism and driving offences.

    PubMed

    Rumbold, John

    2013-10-01

    Automatism is a rarely used defence, but it is particularly used for driving offences because many are strict liability offences. Medical evidence is almost always crucial to argue the defence, and it is important to understand the bars that limit the use of automatism so that the important medical issues can be identified. The issue of prior fault is an important public safeguard to ensure that reasonable precautions are taken to prevent accidents. The total loss of control definition is more problematic, especially with disorders of more gradual onset like hypoglycaemic episodes. In these cases the alternative of 'effective loss of control' would be fairer. This article explores several cases, how the criteria were applied to each, and the types of medical assessment required.

  10. Head tilt during driving.

    PubMed

    Zikovitz, D C; Harris, L R

    1999-05-01

    In order to distinguish between the use of visual and gravito-inertial force reference frames, the head tilt of drivers and passengers were measured as they went around corners at various speeds. The visual curvature of the corners were thus dissociated from the magnitude of the centripetal forces (0.30-0.77 g). Drivers' head tilts were highly correlated with the visually-available estimate of the curvature of the road (r2=0.86) but not with the centripetal force (r2<0.1). Passengers' head tilts were inversely correlated with the lateral forces (r2=0.3-0.7) and seem to reflect a passive sway. The strong correlation of the tilt of drivers' heads with a visual aspect of the road ahead, supports the use of a predominantly visual reference frame for the driving task. PMID:10722313

  11. [Epilepsy and driving].

    PubMed

    Matsuura, Masato

    2014-05-01

    In Japan, the Road Traffic Act was amended in June 2013, including new penalty to false statement in a disease condition declaration form, and new voluntary notification system for a doctor who is aware that a person is at high risk for traffic accident and in possession of a driver license. Moreover, New Criminal Law Act was established in November 2013, including a prison sentence of up to 15 years for persons, who under the influence of specific drugs or diseases, causing death or injury to other persons by driving a motor vehicle. Both laws are supposed to be enforced during 2014, after additional resolutions including the review of the laws after five years, considerations so as not to create discrimination due to diseases, etc are examined.

  12. [Epilepsy and driving].

    PubMed

    Matsuura, Masato

    2014-05-01

    In Japan, the Road Traffic Act was amended in June 2013, including new penalty to false statement in a disease condition declaration form, and new voluntary notification system for a doctor who is aware that a person is at high risk for traffic accident and in possession of a driver license. Moreover, New Criminal Law Act was established in November 2013, including a prison sentence of up to 15 years for persons, who under the influence of specific drugs or diseases, causing death or injury to other persons by driving a motor vehicle. Both laws are supposed to be enforced during 2014, after additional resolutions including the review of the laws after five years, considerations so as not to create discrimination due to diseases, etc are examined. PMID:24912298

  13. QUICK RELEASABLE DRIVE

    DOEpatents

    Dickson, J.J.

    1958-07-01

    A quick releasable mechanical drive system suitable for use in a nuclear reactor is described. A small reversible motor positions a control rod by means of a worm and gear speed reducer, a magnetic torque clutch, and a bell crank. As the control rod is raised to the operating position, a heavy coil spring is compressed. In the event of an emergency indicated by either a''scram'' signal or a power failure, the current to the magnetic clutch is cut off, thereby freeing the coil spring and the bell crank positioner from the motor and speed reduction gearing. The coil spring will immediately act upon the bell crank to cause the insertion of the control rod. This arrangement will allow the slow, accurate positioning of the control rod during reactor operation, while providing an independent force to rapidly insert the rod in the event of an emergency.

  14. Rotary drive mechanism

    DOEpatents

    Kenderdine, Eugene W.

    1991-01-01

    A rotary drive mechanism includes a rotary solenoid having a stator and multi-poled rotor. A moving member rotates with the rotor and is biased by a biasing device. The biasing device causes a further rotational movement after rotation by the rotary solenoid. Thus, energization of the rotary solenoid moves the member in one direction to one position and biases the biasing device against the member. Subsequently, de-energization of the rotary solenoid causes the biasing device to move the member in the same direction to another position from where the moving member is again movable by energization and de-energization of the rotary solenoid. Preferably, the moving member is a multi-lobed cam having the same number of lobes as the rotor has poles. An anti-overdrive device is also preferably provided for preventing overdrive in the forward direction or a reverse rotation of the moving member and for precisely aligning the moving member.

  15. A linear programming manual

    NASA Technical Reports Server (NTRS)

    Tuey, R. C.

    1972-01-01

    Computer solutions of linear programming problems are outlined. Information covers vector spaces, convex sets, and matrix algebra elements for solving simultaneous linear equations. Dual problems, reduced cost analysis, ranges, and error analysis are illustrated.

  16. [Application of HHT to driving fatigue in EEG analysis].

    PubMed

    Nan, Jiaofen; Ai, Lingmei; Shen, Jun

    2011-08-01

    Based on the fact that the signals of electroencephalogram (EEG) possess non-linear and non-stationary properties, Hilbert-Huang Transform (HHT) was proposed for the EEG analysis of driving fatigue. Firstly, C4-lead EEG was selected, and the data of normal driving state and fatigue driving state was analyzed by HHT to explore the differences. Then O2-lead EEG was chosen for contrastive analysis of differences between the different leads. It was found through the analysis that the EEG signals had different Hilbert marginal spectrums for different states, and there were also some differences at the same state for the two leads. It can be certain that HHT can well distinguish different states of drivers as a novel approach for driving fatigue detection, and the selected lead may affect detectable results to some extent.

  17. [Driving license and mellitus diabetes].

    PubMed

    Cimino, Luc; Deneufgermain, Alain; Lalau, Jean-Daniel

    2015-10-01

    For the "light group" as for the "heavy group" driving license cannot be issued or renewed to the applicant or drivers suffering from a condition that may constitute or lead to functional disability jeopardize road safety when driving a motor vehicle. The decision to issue or renew the license by the prefectural authority is taken on the advice of the departmental medical commission or a licensed physician. The decree of August 31, 2010 establishes the list of medical conditions incompatible with obtaining or maintaining the driving license or which may give rise to the issue of driving license limited validity. "Diabetes mellitus treated with medications that can cause hypoglycemia" belongs to this list. If the medical control of driving ability comes at the initiative of the user, the treating physician should firstly ensure the understanding of prescribed treatments that can cause hypoglycaemic episodes and other by informing diabetic person she must pass a medical examination of fitness to drive in a licensed physician.

  18. Ka-band MMIC beam steered transmitter array

    NASA Technical Reports Server (NTRS)

    Rascoe, D. L.; Riley, A. L.; Huang, J.; Lubecke, V.; Duffy, L.

    1989-01-01

    A 32-GHz six-element linear transmitter array utilizing monolithic microwave integrated circuit (MMIC) phase shifters and power amplifiers was designed and tested as part of the development of a spacecraft array feed for NASA deep-space communications applications. Measurements of the performance of individual phase shifters, power amplifiers, and microstrip radiators were carried out, and electronic beam steering of the linear array was demonstrated. The switched-line phase shifters were accurate to within 7 percent on average and the power amplifier 1-dB compressed output power varied over 0.3 dB. The array had a beamwidth of 7.5 deg and demonstrated acceptable beam steering over + or - 8 deg. From the results, it can be concluded that this MMIC phased array has adequate beam-scanning capability for use in the two-dimensional array. The areas that need to be improved are the efficiency of the MMIC power amplifier and the insertion loss of the MMIC phase shifter.

  19. SRS Computer Animation and Drive Train System

    NASA Technical Reports Server (NTRS)

    Arthun, Daniel; Schachner, Christian

    2001-01-01

    The spinning rocket simulator (SRS) is an ongoing project at Oral Roberts University. The goal of the SRS is to gather crucial data concerning a spinning rocket under thrust for the purpose of analysis and correction of the coning motion experienced by this type of spacecraft maneuver. The computer animation simulates a virtual, scale model of the component of the SRS that represents the spacecraft itself. This component is known as the (VSM), or virtual spacecraft model. During actual physical simulation, this component of the SRS will experience a coning. The goal of the animation is to cone the VSM within that range to accurately represent the motion of the actual simulator. The drive system of the SRS is the apparatus that turns the actual simulator. It consists of a drive motor, motor mount and chain to power the simulator into motion. The motor mount is adjustable and rigid for high torque application. A digital stepper motor controller actuates the main drive motor for linear acceleration. The chain transfers power from the motor to the simulator via sprockets on both ends.

  20. Evidence for upper Great Lakes waters in the Erie Basin until 10. 5 ka

    SciTech Connect

    Tinkler, K.J. . Dept. of Geology) Lewis, C.F.M. ); Anderson, T.W. ); Cameron, G.D.M.

    1992-01-01

    Modern recession at Niagara Falls suggests that Erie basin flow alone produces a narrower gorge with recession reduced by an order of magnitude. Gorge interpretations relate dimensions to stages of Great Lakes evolution. A published date of 9.8 ka, for upper river shells at Whirlpool State Park favors an interpretation implying 3.5 kilometers of gorge were cut in the period 12.5 ka to 10.5 ka at a rate of 1.75 m/a, a value consistent with the pre-twentieth century rate of 1.37--1.52 m/a. Erie basin discharge alone would be insufficient to excavate the length of gorge seen. Stratigraphic studies of offshore sediments in lake Erie north-east of Long Point based on seismic profiles and core samples show evidence of lake level change. Following decline of the post-Whittlesey (< 13 ka) southwestward-draining proglacial lakes in the Erie basin and the establishment of Lake Iroquois at about 12.5 ka water levels fell to a control on the Niagara Peninsula. Glacial meltwater continued to pass through the Erie basin until 10.5 ka. Negative shifts in delta O-18 suggest increased meltwater flow through the Erie basin and increased lake level between 11 ka and 10.5 ka. An erosional unconformity, lag sediments, and a distinct former shoreface suggest that lake level subsequently fell in the Long Point area of eastern Lake Erie to about 30m below present by about 10.5 ka when meltwater runoff from the upper Great Lakes by-passed Erie basin. Both the lake cores and the gorge recession are consistent with a computational model of flow out to the Erie basin. According to the model great Lakes outflow, augmented by inflow from Lake Agassiz between 11 to 10.5 ka, would yield shorelines at the height attributed to Lake Tonawanda (180--182m), the immediate source of the Niagara River.

  1. Conformational and oligomeric effects on the cysteine pKa of typaredoxin peroxidase

    PubMed Central

    Yuan, Ye; Knaggs, Michael H.; Poole, Leslie B.; Fetrow, Jacquelyn S.; Salsbury, Freddie R.

    2010-01-01

    Typical 2-Cys peroxiredoxins (Prxs) are peroxidases which regulate cell signaling pathways, apoptosis, and differentiation. These enzymes are obligate homodimers, and can form decamers in solution. During catalysis, Prxs exhibit cysteine-dependent reactivity which requires the deprotonation of the peroxidatic cysteine (Cp) supported by a lowered pKa in the initial step. We present the results of molecular dynamics simulations combined with pKa calculations on the monomeric, dimeric and decameric forms of one typical 2-Cys Prx, the tryparedoxin peroxidase from Trypanosoma cruzi (PDB id, 1uul). The calculations indicate that Cp (C52) pKa values are highly affected by oligomeric state; an unshifted Cp pKa (~ 8.3, comparable to the pKa of isolated cysteine) is calculated for the monomer. In the dimers, starting with essentially identical structures, the Cps evolve dynamically asymmetric pKas during the simulations; one subunit’s Cp pKa is shifted downward at a time, while the other is unshifted. However, when averaged over time, or multiple simulations, the two subunits within a dimer exhibit the same Cp, showing no preference for a lowered pKa in either subunit. Two conserved pathways that communicate the asymmetric pKas between Cps of different subunits can be identified. In the decamer, all the Cp pKas are shifted downward, with slight asymmetry in the dimers which form the decamers. Structural analyses implicate oligomerization effects as responsible for these oligomeric state-dependent Cp pKa shifts. The intra-dimer and the inter-dimer subunit contacts in the decamer restrict the conformations of the side chains of several residues (T49, T54 and E55) calculated to be key in shifting the Cp pKa. In addition, the backbone fluctuations of a few residues (M46, D47 and F48) result in a different electrostatic environment for the Cp in dimers relative to the monomers. These side chain and backbone interactions which contribute to pKa modulation indicate the importance

  2. Linear-Algebra Programs

    NASA Technical Reports Server (NTRS)

    Lawson, C. L.; Krogh, F. T.; Gold, S. S.; Kincaid, D. R.; Sullivan, J.; Williams, E.; Hanson, R. J.; Haskell, K.; Dongarra, J.; Moler, C. B.

    1982-01-01

    The Basic Linear Algebra Subprograms (BLAS) library is a collection of 38 FORTRAN-callable routines for performing basic operations of numerical linear algebra. BLAS library is portable and efficient source of basic operations for designers of programs involving linear algebriac computations. BLAS library is supplied in portable FORTRAN and Assembler code versions for IBM 370, UNIVAC 1100 and CDC 6000 series computers.

  3. Driving anger in Ukraine: Appraisals, not trait driving anger, predict anger intensity while driving.

    PubMed

    Stephens, A N; Hill, T; Sullman, M J M

    2016-03-01

    Trait driving anger is often, but not always, found to predict both the intensity of anger while driving and subsequent crash-related behaviours. However, a number of studies have not found support for a direct relationship between one's tendency to become angry and anger reported while driving, suggesting that other factors may mediate this relationship. The present self-report study investigated whether, in anger provoking driving situations, the appraisals made by drivers influence the relationship between trait and state anger. A sample of 339 drivers from Ukraine completed the 33-item version of the Driver Anger Scale (DAS; Deffenbacher et al., 1994) and eight questions about their most recent experience of driving anger. A structural equation model found that the intensity of anger experienced was predicted by the negative evaluations of the situation, which was in turn predicted by trait driving anger. However, trait driving anger itself did not predict anger intensity; supporting the hypothesis that evaluations of the driving situation mediate the relationship between trait and state anger. Further, the unique structure of the DAS required to fit the data from the Ukrainian sample, may indicate that the anger inducing situations in Ukraine are different to those of a more developed country. Future research is needed to investigate driving anger in Ukraine in a broader sample and also to confirm the role of the appraisal process in the development of driving anger in both developed and undeveloped countries. PMID:26710267

  4. Driving anger in Ukraine: Appraisals, not trait driving anger, predict anger intensity while driving.

    PubMed

    Stephens, A N; Hill, T; Sullman, M J M

    2016-03-01

    Trait driving anger is often, but not always, found to predict both the intensity of anger while driving and subsequent crash-related behaviours. However, a number of studies have not found support for a direct relationship between one's tendency to become angry and anger reported while driving, suggesting that other factors may mediate this relationship. The present self-report study investigated whether, in anger provoking driving situations, the appraisals made by drivers influence the relationship between trait and state anger. A sample of 339 drivers from Ukraine completed the 33-item version of the Driver Anger Scale (DAS; Deffenbacher et al., 1994) and eight questions about their most recent experience of driving anger. A structural equation model found that the intensity of anger experienced was predicted by the negative evaluations of the situation, which was in turn predicted by trait driving anger. However, trait driving anger itself did not predict anger intensity; supporting the hypothesis that evaluations of the driving situation mediate the relationship between trait and state anger. Further, the unique structure of the DAS required to fit the data from the Ukrainian sample, may indicate that the anger inducing situations in Ukraine are different to those of a more developed country. Future research is needed to investigate driving anger in Ukraine in a broader sample and also to confirm the role of the appraisal process in the development of driving anger in both developed and undeveloped countries.

  5. VINETA II: a linear magnetic reconnection experiment.

    PubMed

    Bohlin, H; Von Stechow, A; Rahbarnia, K; Grulke, O; Klinger, T

    2014-02-01

    A linear experiment dedicated to the study of driven magnetic reconnection is presented. The new device (VINETA II) is suitable for investigating both collisional and near collisionless reconnection. Reconnection is achieved by externally driving magnetic field lines towards an X-point, inducing a current in the background plasma which consequently modifies the magnetic field topology. Owing to the open field line configuration of the experiment, the current is limited by the axial sheath boundary conditions. A plasma gun is used as an additional electron source in order to counterbalance the charge separation effects and supply the required current. Two drive methods are used in the device. First, an oscillating current through two parallel conductors drive the reconnection. Second, a stationary X-point topology is formed by the parallel conductors, and the drive is achieved by an oscillating current through a third conductor. In the first setup, the magnetic field of the axial plasma current dominates the field topology near the X-point throughout most of the drive. The second setup allows for the amplitude of the plasma current as well as the motion of the flux to be set independently of the X-point topology of the parallel conductors.

  6. VINETA II: A linear magnetic reconnection experiment

    SciTech Connect

    Bohlin, H. Von Stechow, A.; Rahbarnia, K.; Grulke, O.; Klinger, T.

    2014-02-15

    A linear experiment dedicated to the study of driven magnetic reconnection is presented. The new device (VINETA II) is suitable for investigating both collisional and near collisionless reconnection. Reconnection is achieved by externally driving magnetic field lines towards an X-point, inducing a current in the background plasma which consequently modifies the magnetic field topology. Owing to the open field line configuration of the experiment, the current is limited by the axial sheath boundary conditions. A plasma gun is used as an additional electron source in order to counterbalance the charge separation effects and supply the required current. Two drive methods are used in the device. First, an oscillating current through two parallel conductors drive the reconnection. Second, a stationary X-point topology is formed by the parallel conductors, and the drive is achieved by an oscillating current through a third conductor. In the first setup, the magnetic field of the axial plasma current dominates the field topology near the X-point throughout most of the drive. The second setup allows for the amplitude of the plasma current as well as the motion of the flux to be set independently of the X-point topology of the parallel conductors.

  7. Novel current drive experiments on the CDX-U, HIT, and DIII-D Tokamaks

    SciTech Connect

    Ono, M.; Forest, C.B.; Hwang, Y.S.; Armstrong, R.J.; Choe, W.; Darrow, D.S.; Greene, G.; Jones, T.; Jarboe, T.R.; Martin, A.; Nelson, B.A.; Orvis, D.; Painter, C.; Zhou, L.; Rogers, J.A.; Schaffer, M.J.; Hyatt, A.W.; Pinsker, R.I.; Staebler, G.M.; Stambaugh, R.D.; Strait, E.J.; Greene, K.L.; Leuer, J.A.; Lohr, J.M.

    1992-10-01

    Two types of novel, non-inductive current drive concepts for starting-up and maintaining tokamak discharges have been developed on the CDX-U, HIT, and DIII-D Tokamaks. On CDX-U, a new, non-inductive current drive technique utilizing fully internally generated pressure driven currents has been demonstrated. The measured current density profile shows a non-hollow profile which agrees with a modeling calculation including helicity conserving non-classical current transport providing the ``seed current``. Another current drive concept, dc-helicity injection, has been investigated on, CDX-U, HIT and DIII-D. This method utilizes injection of magnetic helicity via low energy electron currents, maintaining the plasma current through helicity conserving relaxiation. In these experiments, non-ohmic tokamak plasmas were formed and maintained in the tens of kA range.

  8. Novel current drive experiments on the CDX-U, HIT, and DIII-D Tokamaks

    SciTech Connect

    Ono, M.; Forest, C.B.; Hwang, Y.S.; Armstrong, R.J.; Choe, W.; Darrow, D.S.; Greene, G.; Jones, T. . Plasma Physics Lab.); Jarboe, T.R.; Martin, A.; Nelson, B.A.; Orvis, D.; Painter, C.; Zhou, L.; Rogers, J.A. ); Schaffer, M.J.; Hyatt, A.W.; Pinsker, R.I.; Staebler, G.M.; Stambaugh, R.D.; Strait, E.J.; Greene, K.L.; Leuer, J.A.; Lohr, J.

    1992-01-01

    Two types of novel, non-inductive current drive concepts for starting-up and maintaining tokamak discharges have been developed on the CDX-U, HIT, and DIII-D Tokamaks. On CDX-U, a new, non-inductive current drive technique utilizing fully internally generated pressure driven currents has been demonstrated. The measured current density profile shows a non-hollow profile which agrees with a modeling calculation including helicity conserving non-classical current transport providing the seed current''. Another current drive concept, dc-helicity injection, has been investigated on, CDX-U, HIT and DIII-D. This method utilizes injection of magnetic helicity via low energy electron currents, maintaining the plasma current through helicity conserving relaxiation. In these experiments, non-ohmic tokamak plasmas were formed and maintained in the tens of kA range.

  9. 26. CAN CONVEYOR DRIVE MECHANISM Empty can conveyor driving mechanism, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. CAN CONVEYOR DRIVE MECHANISM Empty can conveyor driving mechanism, second floor above canning area. The belt has been removed from the conveyor, but sections of can conveyor tracks are visible on the floor. - Hovden Cannery, 886 Cannery Row, Monterey, Monterey County, CA

  10. VIEW OF BEND IN CEDAR DRIVE WITH 603 CEDAR DRIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BEND IN CEDAR DRIVE WITH 603 CEDAR DRIVE ON RIGHT. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  11. Sedimentation history of the northern North Sea Margin during the last 150 ka

    NASA Astrophysics Data System (ADS)

    Lekens, W. A. H.; Haflidason, H.; Sejrup, H. P.; Nygard, A.; Richter, T.; Vogt, C.; Frederichs, T.

    2009-03-01

    The Norwegian Channel Ice Stream (NCIS) is one the defining features of the Fennoscandian icesheet. Still little is known of the detailed dynamics of this ice stream in relation to regional changes in ice cover, paleoceanographic and climatic changes. Sedimentological data from core MD99-2283 in combination with seismic data allow a detailed chronological reconstruction of the outbuilding of the margin and the ice extent in southern Scandinavia through the last 150 ka. An integrated stratigraphy of the margin is presented and compared to the glacial history. Changes in the regional ice cover are reflected in the accumulation rates, the clay mineralogy, the coarse chalk fraction and the number of IRD >2 mm in core MD99-2283, while the sedimentation on the North Sea Fan as derived from seismic data provides direct evidence for the glacial activity at the shelf edge. Tentative evidence was found for two Early Weichselian glacial advances in southern Scandinavia and possibly Scotland at around 110 and 80 ka BP. From 42 cal ka BP the ice cover expanded in southern Fennoscandia and led to increased deposition on the margin and the occurrence of local melt water outbursts. Significantly increased accumulation rates, coarse chalk, local meltwater output and smectite occur during the ice expansion in the North Sea from around 34 cal ka BP. The main outbuilding phase of the NSF during the last glacial cycle occurred after 30 cal ka BP. From around 24 cal ka BP the NCIS became highly active and advanced at least three times prior to the final retreat from the shelf edge around 19.0 cal ka BP.

  12. Molecular Paleoclimate Reconstructions over the Last 9 ka from a Peat Sequence in South China.

    PubMed

    Wang, Xinxin; Huang, Xianyu; Sachse, Dirk; Ding, Weihua; Xue, Jiantao

    2016-01-01

    To achieve a better understanding of Holocene climate change in the monsoon regions of China, we investigated the molecular distributions and carbon and hydrogen isotope compositions (δ13C and δD values) of long-chain n-alkanes in a peat core from the Shiwangutian (SWGT) peatland, south China over the last 9 ka. By comparisons with other climate records, we found that the δ13C values of the long-chain n-alkanes can be a proxy for humidity, while the δD values of the long-chain n-alkanes primarily recorded the moisture source δD signal during 9-1.8 ka BP and responded to the dry climate during 1.8-0.3 ka BP. Together with the average chain length (ACL) and the carbon preference index (CPI) data, the climate evolution over last 9 ka in the SWGT peatland can be divided into three stages. During the first stage (9-5 ka BP), the δ13C values were depleted and CPI and Paq values were low, while ACL values were high. They reveal a period of warm and wet climate, which is regarded as the Holocene optimum. The second stage (5-1.8 ka BP) witnessed a shift to relatively cool and dry climate, as indicated by the more positive δ13C values and lower ACL values. During the third stage (1.8-0.3 ka BP), the δ13C, δD, CPI and Paq values showed marked increase and ACL values varied greatly, implying an abrupt change to cold and dry conditions. This climate pattern corresponds to the broad decline in Asian monsoon intensity through the latter part of the Holocene. Our results do not support a later Holocene optimum in south China as suggested by previous studies.

  13. Molecular Paleoclimate Reconstructions over the Last 9 ka from a Peat Sequence in South China.

    PubMed

    Wang, Xinxin; Huang, Xianyu; Sachse, Dirk; Ding, Weihua; Xue, Jiantao

    2016-01-01

    To achieve a better understanding of Holocene climate change in the monsoon regions of China, we investigated the molecular distributions and carbon and hydrogen isotope compositions (δ13C and δD values) of long-chain n-alkanes in a peat core from the Shiwangutian (SWGT) peatland, south China over the last 9 ka. By comparisons with other climate records, we found that the δ13C values of the long-chain n-alkanes can be a proxy for humidity, while the δD values of the long-chain n-alkanes primarily recorded the moisture source δD signal during 9-1.8 ka BP and responded to the dry climate during 1.8-0.3 ka BP. Together with the average chain length (ACL) and the carbon preference index (CPI) data, the climate evolution over last 9 ka in the SWGT peatland can be divided into three stages. During the first stage (9-5 ka BP), the δ13C values were depleted and CPI and Paq values were low, while ACL values were high. They reveal a period of warm and wet climate, which is regarded as the Holocene optimum. The second stage (5-1.8 ka BP) witnessed a shift to relatively cool and dry climate, as indicated by the more positive δ13C values and lower ACL values. During the third stage (1.8-0.3 ka BP), the δ13C, δD, CPI and Paq values showed marked increase and ACL values varied greatly, implying an abrupt change to cold and dry conditions. This climate pattern corresponds to the broad decline in Asian monsoon intensity through the latter part of the Holocene. Our results do not support a later Holocene optimum in south China as suggested by previous studies. PMID:27505008

  14. Molecular Paleoclimate Reconstructions over the Last 9 ka from a Peat Sequence in South China

    PubMed Central

    Wang, Xinxin; Huang, Xianyu; Sachse, Dirk; Ding, Weihua; Xue, Jiantao

    2016-01-01

    To achieve a better understanding of Holocene climate change in the monsoon regions of China, we investigated the molecular distributions and carbon and hydrogen isotope compositions (δ13C and δD values) of long-chain n-alkanes in a peat core from the Shiwangutian (SWGT) peatland, south China over the last 9 ka. By comparisons with other climate records, we found that the δ13C values of the long-chain n-alkanes can be a proxy for humidity, while the δD values of the long-chain n-alkanes primarily recorded the moisture source δD signal during 9–1.8 ka BP and responded to the dry climate during 1.8–0.3 ka BP. Together with the average chain length (ACL) and the carbon preference index (CPI) data, the climate evolution over last 9 ka in the SWGT peatland can be divided into three stages. During the first stage (9–5 ka BP), the δ13C values were depleted and CPI and Paq values were low, while ACL values were high. They reveal a period of warm and wet climate, which is regarded as the Holocene optimum. The second stage (5–1.8 ka BP) witnessed a shift to relatively cool and dry climate, as indicated by the more positive δ13C values and lower ACL values. During the third stage (1.8–0.3 ka BP), the δ13C, δD, CPI and Paq values showed marked increase and ACL values varied greatly, implying an abrupt change to cold and dry conditions. This climate pattern corresponds to the broad decline in Asian monsoon intensity through the latter part of the Holocene. Our results do not support a later Holocene optimum in south China as suggested by previous studies. PMID:27505008

  15. Magnetostrictive direct drive motor

    NASA Technical Reports Server (NTRS)

    Naik, Dipak; Dehoff, P. H.

    1991-01-01

    Highly magnetostrictive materials such as Tb.3Dy.7Fe2, commercially known as TERFENOL-D, have been used to date in a variety of devices such as high power actuators and linear motors. The larger magnetostriction available in twinned single crystal TERFENOL-D, approx. 2000 ppm at moderate magnetic field strengths, makes possible a new generation of magnetomechanical devices. NASA researchers are studying the potential of this material as the basis for a direct microstepping rotary motor with torque densities on the order of industrial hydraulics and five times greater than that of the most efficient, high power electric motors. Such a motor would be a micro-radian stepper, capable of precision movements and self-braking in the power-off state. Innovative mechanical engineering techniques are juxtaposed on proper magnetic circuit design to reduce losses in structural flexures, inertias, thermal expansions, eddy currents, and magneto-mechanical coupling, thus optimizing motor performance and efficiency. Mathematical models are presented, including magnetic, structural, and both linear and nonlinear dynamic calculations and simulations. In addition, test results on prototypes are presented.

  16. Variations and controlling factors of the coccolith weight in the Western Pacific Warm Pool over the last 200 ka

    NASA Astrophysics Data System (ADS)

    Liang, Dan; Liu, Chuanlian

    2016-06-01

    Using a coccolith weight analytic software (Particle Analyser), we analyze most abundant coccolith species in a sediment core from the central Western Pacific Warm Pool (WPWP) and calculate coccolith size and weight variations over the last 200 ka. These variations are compared with the trends of sea surface temperature (SST), primary productivity (PP), sea surface salinity (SSS), and insolation. Our results demonstrate that the size and weight of the coccoliths varied in response to variations of these factors, and their average total weight is primarily related to the relative abundance of the dominant species GEO ( Gephyrocapsa oceanica). The variation in weight of EMI ( Emiliania huxleyi) and GEE ( Gephyrocapsa ericsonii) are mainly influenced by nutrients, and the variation of GEM ( G. muellerae conformis) and GEO ( G. oceanica) weight are mainly influenced by SST. For all of the taxa weight, PP and SST present apparent precession or semi-precession cycles, we consider that the mono-coccolith weight of the Equatorial Western Pacific is primarily affected by precession drived thermocline and nutricline variation.

  17. Natural death while driving.

    PubMed

    Oström, M; Eriksson, A

    1987-07-01

    Of sudden natural deaths while driving, 126 occurred during 1980 through 1985 in the northern half of Sweden. The mean age of the 69 car driver victims was 59 years, considerably higher than that of traumatic car deaths, and all but 2 were males. The mean age of 57 operators of other vehicles was 66 years, and of these, 6 were women. Seven car drivers were stricken during commercial employment. Most accidents occurred during daytime and the distribution of the weekdays was fairly even. Ischemic heart disease accounted for 112 deaths, and other cardiovascular diseases for an additional 9 deaths. Only 1/5 of the victims experienced previous symptoms of disease. Out of at least 31 other persons at risk in the car deaths, only 2 passengers suffered minor injuries. The trauma in the deceased was in most cases minor in both car and other vehicle deaths. Property damage was also minimal. At least 1/3 of the drivers were able to stop the car before becoming unconscious. In none of the car cases was alcohol detected in the blood, while alcohol was identified in at least 2 of the other vehicle victims. The findings here agree with previous studies that natural deaths at the wheel are fairly uncommon, and that the risk for other persons is not significant. The value of adequate postmortem examinations of drivers dying in traffic is stressed--natural deaths can otherwise be overlooked. PMID:3612079

  18. Drive-By Pharming

    NASA Astrophysics Data System (ADS)

    Stamm, Sid; Ramzan, Zulfikar; Jakobsson, Markus

    This paper describes an attack concept termed Drive-by Pharming where an attacker sets up a web page that, when simply viewed by the victim (on a JavaScript-enabled browser), attempts to change the DNS server settings on the victim's home broadband router. As a result, future DNS queries are resolved by a DNS server of the attacker's choice. The attacker can direct the victim's Internet traffic and point the victim to the attacker's own web sites regardless of what domain the victim thinks he is actually going to, potentially leading to the compromise of the victim's credentials. The same attack methodology can be used to make other changes to the router, like replacing its firmware. Routers could then host malicious web pages or engage in click fraud. Since the attack is mounted through viewing a web page, it does not require the attacker to have any physical proximity to the victim nor does it require the explicit download of traditional malicious software. The attack works under the reasonable assumption that the victim has not changed the default management password on their broadband router.

  19. Records of the paleoclimate during the fast transgression period (13 ka BP-8 ka BP) from the mud area on the inner shelf of the East China Sea

    NASA Astrophysics Data System (ADS)

    Liu, S.

    2015-12-01

    A 35.30m-long core (MZ02) recovered from a water depth of 32.4m from the inner shelf mud deposit of the East China Sea was analyzed for sedimentary characteristics, color reflectance, clay mineral, and element geochemistry components as well as by AMS 14C dating to research the sedimentation rate, sediment provenance and paleocwan mountainous river and clay fralimate evolution during the fast transgression period in the study area. Rare earth element and clay mineral proxies indicated that the mixed provenance sediment accumulated in the foreshore-nearshore region at the beginning of the fast transgression period, with a higher sedimentation rate of 5.58m/ka. While from 9800-9500 a B.P., the sedimentation rate keep lower about 1.73m/ka, and the sediment provenance changed obviously, silt fraction were apt to Taiction prone to be transported from the Yangtze River. Multiple proxy system including sediment redness (a*), chemical index of alteration (CIA), clay mineral proxy (smectite/kaolinite), major and trace element proxy (CaO/MgO, Ba/Sr) also showed a good paleoclimate record during the fast transgression period, which could be divided into three units. All the proxies changed little during Unit I (13-11.3ka B.P.) and revealed the climate kept in a relative stable level. Obvious fluctuation happened in Unit II (11.3-10.1ka B.P.) and the temperature kept decreasing more than 1ka till the Younger Dryas event, showed a well regional response to global climate changes. While continuous warming trend resumed again in Unit III (10.1-8 ka B.P.), which may be the signal for Holocene warm period. In addition, we also found significant 80yr, 89yr and 100yr cycles in our CIA, CaO/MgO and Ba/Sr records that imply a possible solar influence on the regional climate changes during the fast transgression period. Keywords: East China Sea, provenance, transgression, mud deposit, late Pleistocene, paleoclimate

  20. Handbook for Driving Knowledge Testing.

    ERIC Educational Resources Information Center

    Pollock, William T.; McDole, Thomas L.

    Materials intended for driving knowledge test development for use by operational licensing and education agencies are presented. A pool of 1,313 multiple choice test items is included, consisting of sets of specially developed and tested items covering principles of safe driving, legal regulations, and traffic control device knowledge pertinent to…

  1. Bidirectional drive and brake mechanism

    NASA Technical Reports Server (NTRS)

    Swan, Scott A. (Inventor)

    1991-01-01

    A space transport vehicle is disclosed as including a body which is arranged to be movably mounted on an elongated guide member disposed in outer space and driven therealong. A drive wheel is mounted on a drive shaft and arranged to be positioned in rolling engagement with the elongated guide carrying the vehicle. A brake member is arranged on the drive shaft for movement into and out of engagement with an adjacent surface of the drive wheel. An actuator is mounted on the body to be manually moved back and forth between spaced positions in an arc of movement. A ratchet-and-pawl mechanism is arranged to operate upon movements of the actuator in one direction between first and second positions for coupling the actuator to the drive wheel to incrementally rotate the wheel in one rotational direction and to operate upon movements of the actuator in the opposite direction for uncoupling the actuator from the wheel. The brake member is threadedly coupled to the drive shaft in order that the brake member will be operated only when the actuator is moved on beyond its first and second positions for shifting the brake member along the drive shaft and into frictional engagement with the adjacent surface on the drive wheel.

  2. Students: You... Alcohol and Driving.

    ERIC Educational Resources Information Center

    Department of Transportation, Washington, DC.

    The purpose of this manual is to provide accurate information about alcohol and about drinking and driving, so that the student may make responsible decisions about both. It covers youth drinking, drinking and driving, and the individual's responsibility to others in drinking situations. The booklet consists of eight readings, as well as…

  3. Equatorial Precession in the Control Software of the Ka-Band Object Observation and Monitoring Experiment

    NASA Technical Reports Server (NTRS)

    Jakeman, Hali L.

    2013-01-01

    The Ka-Band Object Observation and Monitoring, or KaBOOM, project is designed mainly to track and characterize near Earth objects. However, a smaller goal of the project would be to monitor pulsars and study their radio frequency signals for use as a clock in interstellar travel. The use of pulsars and their timing accuracy has been studied for decades, but never in the Ka-band of the radio frequency spectrum. In order to begin the use of KaBOOM for this research, the control systems need to be analyzed to ensure its capability. Flaws in the control documentation leave it unclear as to whether the control software processes coordinates from the J200 epoch. This experiment will examine the control software of the Intertronic 12m antennas used for the KaBOOM project and detail its capabilities in its "equatorial mode." The antennas will be pointed at 4 chosen points in the sky on several days while probing the virtual azimuth and elevation (horizon coordinate) registers. The input right ascension and declination coordinates will then be converted separately from the control software to horizontal coordinates and compared, thus determining the ability of the control software to process equatorial coordinates.

  4. Performance of a Ka-band transponder breadboard for deep-space applications

    NASA Technical Reports Server (NTRS)

    Mysoor, N. R.; Lane, J. P.; Kayalar, S.; Kermode, A. W.

    1995-01-01

    This article summarizes the design concepts applied in the development of and advanced Ka-band (34.4 GHz/32 GHz) transponder breadboard for the next generation of space communications systems applications. The selected architecture upgrades the X-band (7.2 GHz/8.4 GHz) deep-space transponder (DST) to provide Da-band up/Ka- and X-band down capability. The Ka-band transponder breadboard incorporates several state-of-the-art components, including sampling mixers, a Ka-band dielectric resonator oscillator, and microwave monolithic integrated circuits (MMICs). The MMICs that were tested in the breadboard include upconverters, downconverters, automatic gain control circuits, mixers, phase modulators, and amplifiers. The measured receiver dynamic range, tracking range, acquisition rate, static phase error, and phase jitter characteristics of the Ka-band breadboard interfaced to the advanced engineering model X-band DST are in good agreement with the expected performance. The results show a receiver tracking threshold of -149 dBm with a dynamic range of 80 dB and a downlink phase jitter of 7 deg rms. The analytical results of phase noise and Allan standard deviation are in good agreement with the experimental results.

  5. A 600-ka Arctic sea-ice record from Mendeleev Ridge based on ostracodes

    NASA Astrophysics Data System (ADS)

    Cronin, T. M.; Polyak, L.; Reed, D.; Kandiano, E. S.; Marzen, R. E.; Council, E. A.

    2013-11-01

    Arctic paleoceanography and sea-ice history were reconstructed from epipelagic and benthic ostracodes from a sediment core (HLY0503-06JPC, 800 m water depth) located on the Mendeleev Ridge, Western Arctic Ocean. The calcareous microfaunal record (ostracodes and foraminifers) covers several glacial/interglacial cycles back to estimated Marine Isotope Stage 13 (MIS 13, ˜500 ka) with an average sedimentation rate of ˜0.5 cm/ka for most of the stratigraphy (MIS 5-13). Results based on ostracode assemblages and an unusual planktic foraminiferal assemblage in MIS 11 dominated by a temperate-water species Turborotalita egelida show that extreme interglacial warmth, high surface ocean productivity, and possibly open ocean convection characterized MIS 11 and MIS 13 (˜400 and 500 ka, respectively). A major shift in western Arctic Ocean environments toward perennial sea ice occurred after MIS 11 based on the distribution of an ice-dwelling ostracode Acetabulastoma arcticum. Spectral analyses of the ostracode assemblages indicate sea ice and mid-depth ocean circulation in western Arctic Ocean varied primarily at precessional (˜22 ka) and obliquity (˜40 ka) frequencies.

  6. Geological record of meltwater events at Qinghai Lake, China from the past 40 ka

    NASA Astrophysics Data System (ADS)

    Zhou, Weijian; Liu, Taibei; Wang, Hao; An, Zhisheng; Cheng, Peng; Zhu, Yizhi; Burr, G. S.

    2016-10-01

    We report here on a previously unpublished sediment core from Qinghai Lake, China, that preserves a continuous record of sedimentation for the past 40 ka. A striking feature of the record is a set of distinct meltwater events recorded at 35, 19 and 14 ka respectively. These events are manifest as distinct pulses of relatively old organic radiocarbon in the sediments. We interpret these as a signal of glacial melting in the Qinghai Lake watershed. The meltwater signals are closely correlated to temperature and precipitation records associated with deglaciation. The events at 19 ka and 14 ka correspond to well-established high latitude Melt Water Pulse (MWP) events during Marine Isotope Stage (MIS) 2, and the 35 ka event corresponds to a period of pervasive high lake levels in western China during late MIS 3. We interpret these anomalous dates as the result of relatively old carbon that was destabilized by the glaciers, and released into the lake as the glaciers melted. The data indicate that this process takes thousands of years. We expect that the approach employed here to identify these events is generally applicable to any lake system with a significant glacial meltwater component.

  7. Overview of Ka-band communications technology requirements for the space exploration initiative

    NASA Technical Reports Server (NTRS)

    Miller, Edward F.

    1991-01-01

    In the Space Exploration Initiative, Ka-band frequencies are likely to carry the bulk of the communications traffic both in the vicinity of and on the return links from the moon and Mars. The four exploration architectures identified by the Synthesis Group are examined and Ka-band technology requirements to meet the data traffic needs and schedule are identified. Specific Ka-band technology requirements identified are: transmitters - 0.5 to 200 W with high efficiency; antennas - 5m and 9m diameter, with multiple beams and/or scanning beams; and spacecraft receivers - noise figure of 2 dB. For each component, the current state of technology is assessed and needed technology development programs are identified. It is concluded that to meet the schedules of lunar and Mars precursor missions beginning in approximately the year 2000, aggressive technology development and advanced development programs are required immediately for Ka-band communications systems components. Additionally, the greater data transmission rates for the cargo and piloted phases of the exploration program require further Ka-band communications technology developments targeted for operations beginning in about 2010.

  8. Ka-band monopulse antenna-pointing systems analysis and simulation

    NASA Technical Reports Server (NTRS)

    Lo, V. Y.

    1996-01-01

    NASA 's Deep Space Network (DSN) has been using both 70-m and 34-m reflector antennas to communicate with spacecraft at S-band (2.3 GHz) and X-band (8.45 GHz). To improve the quality of telecommunication and to meet future mission requirements, JPL has been developing 34-m Ka-band (32-GHz) beam waveguide antennas. Presently, antenna pointing operates in either the open-loop mode with blind pointing using navigation predicts or the closed-loop mode with conical scan (conscan). Pointing accuracy under normal conscan operating conditions is in the neighborhood of 5 mdeg. This is acceptable at S- and X-bands, but not enough at Ka-band. Due to the narrow beamwidth at Ka-band, it is important to improve pointing accuracy significantly (approximately 2 mdeg). Monopulse antenna tracking is one scheme being developed to meet the stringent pointing-accuracy requirement at Ka-band. Other advantages of monopulse tracking include low sensitivity to signal amplitude fluctuations as well as single-pulse processing for acquisition and tracking. This article presents system modeling, signal processing, simulation, and implementation of Ka-band monopulse tracking feed for antennas in NASA/DSN ground stations.

  9. Ka-Band Monopulse Antenna-Pointing Systems Analysis and Simulation

    NASA Technical Reports Server (NTRS)

    Lo, V. Y.

    1996-01-01

    NASA's Deep Space Network (DSN) has been using both 70-m and 34-m reflector antennas to communicate with spacecraft at S-band (2.3 GHz) and X-band (8.45 GHz). To improve the quality of telecommunication and to meet future mission requirements, JPL has been developing 34-m Ka-band (32-GHz) beamwave guide antennas. Presently, antenna pointing operates in either the open-loop mode with blind pointing using navigation predicts or the closed-loop mode with conical scan (conscan). Pointing accuracy under normal conscan operating conditions is in the neighborhood of 5 mdeg. This is acceptable at S- and X-bands, but not enough at Ka-band. Due to the narrow beamwidth at Ka-band, it is important to improve pointing accuracy significantly (approx. 2 mdeg). Monopulse antenna tracking is one scheme being developed to meet the stringent pointing-accuracy requirement at Ka-band. Other advantages of monopulse tracking include low sensitivity to signal amplitude fluctuations as well as single-pulse processing for acquisition and tracking. This article presents system modeling, signal processing, simulation, and implementation of Ka-band monopulse tracking feed for antennas in NASA/DSN ground stations.

  10. Ka-Band Monopulse Antenna-Pointing Systems Analysis and Simulation

    NASA Astrophysics Data System (ADS)

    Lo, V. Y.

    1995-10-01

    NASA's Deep Space Network (DSN) has been using both 70-m and 34-m reflector antennas to communicate with spacecraft at S-band (2.3 GHz) and X-band (8.45 GHz). To improve the quality of telecommunication and to meet future mission requirements, JPL has been developing 34-m Ka-band (32-GHz) beam-waveguide antennas. Presently, antenna pointing operates in either the open-loop mode with blind pointing using navigation predicts or the closed-loop mode with conical scan (conscan). Pointing accuracy under normal conscan operating conditions is in the neighborhood of 5 mdeg. This is acceptable at S- and X-bands, but not enough at Ka-band. Due to the narrow beamwidth at Ka-band, it is important to improve pointing accuracy significantly (~2 mdeg). Monopulse antenna tracking is one scheme being developed to meet the stringent pointing-accuracy requirement at Ka-band. Other advantages of monopulse tracking include low sensitivity to signal amplitude fluctuations as well as single-pulse processing for acquisition and tracking. This article presents system modeling, signal processing, simulation, and implementation of Ka-band monopulse tracking feed for antennas in NASA/DSN ground stations.

  11. A 600-ka Arctic sea-ice record from Mendeleev Ridge based on ostracodes

    USGS Publications Warehouse

    Cronin, Thomas M.; Polyak, L.V.; Reed, D.; Kandiano, E. S.; Marzen, R. E.; Council, E. A.

    2013-01-01

    Arctic paleoceanography and sea-ice history were reconstructed from epipelagic and benthic ostracodes from a sediment core (HLY0503-06JPC, 800 m water depth) located on the Mendeleev Ridge, Western Arctic Ocean. The calcareous microfaunal record (ostracodes and foraminifers) covers several glacial/interglacial cycles back to estimated Marine Isotope Stage 13 (MIS 13, ∼500 ka) with an average sedimentation rate of ∼0.5 cm/ka for most of the stratigraphy (MIS 5–13). Results based on ostracode assemblages and an unusual planktic foraminiferal assemblage in MIS 11 dominated by a temperate-water species Turborotalita egelida show that extreme interglacial warmth, high surface ocean productivity, and possibly open ocean convection characterized MIS 11 and MIS 13 (∼400 and 500 ka, respectively). A major shift in western Arctic Ocean environments toward perennial sea ice occurred after MIS 11 based on the distribution of an ice-dwelling ostracode Acetabulastoma arcticum. Spectral analyses of the ostracode assemblages indicate sea ice and mid-depth ocean circulation in western Arctic Ocean varied primarily at precessional (∼22 ka) and obliquity (∼40 ka) frequencies.

  12. Sea-level records at ~80 ka from tectonically stable platforms: Florida and Bermuda

    USGS Publications Warehouse

    Ludwig, K. R.; Muhs, D.R.; Simmons, K.R.; Halley, R.B.; Shinn, E.A.

    1996-01-01

    Studies from technically active coasts on New Guinea and Barbados have suggested that sea level at ???80 ka was significantly lower than present, whereas data from the Atlantic and Pacific coasts of North America indicate an ???80 ka sea level close to that of the present. We determined ages of corals from a shallow submerged reef off the Florida Keys and an emergent marine deposit on Bermuda. Both localities are on tectonically stable platforms distant from plate boundaries. Uranium-series ages show that corals at both localities grew during the ???80 ka sea-level highstand, and geologic data show that sea level at that time was no lower than 7-9 m below present (Florida) and may have been 1-2 m above present (Bermuda). The ice-volume discrepancy of the 80 ka sea-level estimates is greater than the volume of the Greenland or West Antarctic ice sheets. Comparison of our ages with high-latitude insolation values indicates that the sea-level stand near the present at ???80 ka could have been orbitally forced.

  13. Driving difficulties in Parkinson's disease

    PubMed Central

    Rizzo, Matthew; Uc, Ergun Y; Dawson, Jeffrey; Anderson, Steven; Rodnitzky, Robert

    2011-01-01

    Safe driving requires the coordination of attention, perception, memory, motor and executive functions (including decision-making) and self-awareness. PD and other disorders may impair these abilities. Because age or medical diagnosis alone is often an unreliable criterion for licensure, decisions on fitness to drive should be based on empirical observations of performance. Linkages between cognitive abilities measured by neuropsychological tasks, and driving behavior assessed using driving simulators, and natural and naturalistic observations in instrumented vehicles, can help standardize the assessment of fitness-to-drive. By understanding the patterns of driver safety errors that cause crashes, it may be possible to design interventions to reduce these errors and injuries and increase mobility. This includes driver performance monitoring devices, collision alerting and warning systems, road design, and graded licensure strategies. PMID:20187237

  14. Quantum gates by periodic driving

    PubMed Central

    Shi, Z. C.; Wang, W.; Yi, X. X.

    2016-01-01

    Topological quantum computation has been extensively studied in the past decades due to its robustness against decoherence. One way to realize the topological quantum computation is by adiabatic evolutions—it requires relatively long time to complete a gate, so the speed of quantum computation slows down. In this work, we present a method to realize single qubit quantum gates by periodic driving. Compared to adiabatic evolution, the single qubit gates can be realized at a fixed time much shorter than that by adiabatic evolution. The driving fields can be sinusoidal or square-well field. With the sinusoidal driving field, we derive an expression for the total operation time in the high-frequency limit, and an exact analytical expression for the evolution operator without any approximations is given for the square well driving. This study suggests that the period driving could provide us with a new direction in regulations of the operation time in topological quantum computation. PMID:26911900

  15. [Driving and health at work].

    PubMed

    Giorgio, Marie-Thérèse

    2015-09-01

    The role of the occupational physician is to prevent occupational accidents and diseases. Therefore, he is the one to decide if a worker is fit to drive in the context of his professional activity, including in cases where no specific driving license is required (e.g. forklift truck, mobile crane). This decision is an important one, as two thirds of fatal occupational accidents occur on the road. The decision is made on the basis of both a medical examination and the regulation, which indicates all contraindications to driving. The physician's responsibility is involved, as is the employer's, as he must ensure that his employee is fit to drive and possesses a valid driving license at all times.

  16. Holokinetic drive: centromere drive in chromosomes without centromeres.

    PubMed

    Bureš, Petr; Zedek, František

    2014-08-01

    Similar to how the model of centromere drive explains the size and complexity of centromeres in monocentrics (organisms with localized centromeres), our model of holokinetic drive is consistent with the divergent evolution of chromosomal size and number in holocentrics (organisms with nonlocalized centromeres) exhibiting holokinetic meiosis (holokinetics). Holokinetic drive is proposed to facilitate chromosomal fission and/or repetitive DNA removal (or any segmental deletion) when smaller homologous chromosomes are preferentially inherited or chromosomal fusion and/or repetitive DNA proliferation (or any segmental duplication) when larger homologs are preferred. The hypothesis of holokinetic drive is supported primarily by the negative correlation between chromosome number and genome size that is documented in holokinetic lineages. The supporting value of two older cross-experiments on holokinetic structural heterozygotes (the rush Luzula elegans and butterflies of the genus Antheraea) that indicate the presence of size-preferential homolog transmission via female meiosis for holokinetic drive is discussed, along with the further potential consequences of holokinetic drive in comparison with centromere drive.

  17. Electric vehicle drive systems

    NASA Astrophysics Data System (ADS)

    Appleyard, M.

    1992-01-01

    New legislation in the State of California requires that 2% of vehicles sold there from 1998 will be 'zero-emitting'. This provides a unique market opportunity for developers of electric vehicles but substantial improvements in the technology are probably required if it is to be successfully exploited. There are around a dozen types of battery that are potentially relevant to road vehicles but, at the present, lead/acid and sodium—sulphur come closest to combining acceptable performance, life and cost. To develop an efficient, lightweight electric motor system requires up-to-date techniques of magnetics design, and the latest power-electronic and microprocessor control methods. Brushless machines, coupled with solid-state inverters, offer the most economical solution for mass production, even though their development costs are higher than for direct-current commutator machines. Fitted to a small car, even the highest energy-density batteries will only provide around 200 km average range before recharging. Therefore, some form of supplementary on-board power generation will probably be needed to secure widespread acceptance by the driving public. Engine-driven generators of quite low power can achieve useful increases in urban range but will fail to qualify as 'zero-emitting'. On the other hand, if the same function could be economically performed by a small fuel-cell using hydrogen derived from a methanol reformer, then most of the flexibility provided by conventional vehicles would be retained. The market prospects for electric cars would then be greatly enhanced and their dependence on very advanced battery technology would be reduced.

  18. PolKa: A Tunable Polarimeter for Submillimeter Bolometer Arrays

    NASA Astrophysics Data System (ADS)

    Siringo, G.; Kreysa, E.; Menten, K. M.; Reichertz, L. A.

    2005-12-01

    A new polarimeter has been constructed to be used with the bolometer arrays developed at the Max-Planck-Institut für Radioastronomie in Bonn. The new polarimeter has the unique characteristic of being tunable over a wide range of wavelengths and of producing negligible absorption. It has been used at the Heinrich Hertz Telescope to measure the linear polarization of quasars and of extended sources inside our Galaxy. We detected polarization in the quasars 3C 279 and QSO B1633+382. In 3C 279 we also detected polarization variability on a time scale of a week. We also produced maps of three extended sources: the Becklin-Neugebauer/Kleinmann-Low complex in the Orion Molecular Cloud 1 (OMC 1), a filamentary cloud in OMC 3, and the massive star-forming region IRAS 05358+3543. The polarimeter has low spurious polarization and a high modulation efficiency, and the tests at the telescope show that it is well suited to become a permanent facility.

  19. Linear collider: a preview

    SciTech Connect

    Wiedemann, H.

    1981-11-01

    Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.

  20. Dielectric Wakefield Accelerator to drive the future FEL Light Source.

    SciTech Connect

    Jing, C.; Power, J.; Zholents, A. )

    2011-04-20

    X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a {approx}100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, {approx}1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency {approx}38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm{sup 2} in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.

  1. Note: Design and tests of a 13 kA-6.5 kV thyristor switch for a pulsed inductive vacuum ultraviolet source.

    PubMed

    Teske, C; Lee, B-J; Jacoby, J; Schweizer, W; Sun, J Chao

    2010-04-01

    In this paper, the design, construction, and test procedure of a closing switch prototype based on thyristors is described. In particular, details are given about the design criteria and about the triggering board architecture, which is a high side biased, self supplied unit using the electrical energy derived from a local snubber network for the gate drive. The structure guarantees a hard firing gate pulse for the required high dI/dt application. Further, the results of the prototype tests are presented and discussed. The stack assembly has a holding voltage of 6.5 kV and is used for switching a series resonant circuit with a ringing frequency of 12 kHz for a pulsed inductive vacuum ultraviolet source. Maximum current amplitudes of 13 kA and pulse energies of more than 600 J were switched during the test procedure.

  2. Novel linear piezoelectric motor for precision position stage

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Shi, Yunlai; Zhang, Jun; Wang, Junshan

    2016-03-01

    Conventional servomotor and stepping motor face challenges in nanometer positioning stages due to the complex structure, motion transformation mechanism, and slow dynamic response, especially directly driven by linear motor. A new butterfly-shaped linear piezoelectric motor for linear motion is presented. A two-degree precision position stage driven by the proposed linear ultrasonic motor possesses a simple and compact configuration, which makes the system obtain shorter driving chain. Firstly, the working principle of the linear ultrasonic motor is analyzed. The oscillation orbits of two driving feet on the stator are produced successively by using the anti-symmetric and symmetric vibration modes of the piezoelectric composite structure, and the slider pressed on the driving feet can be propelled twice in only one vibration cycle. Then with the derivation of the dynamic equation of the piezoelectric actuator and transient response model, start-upstart-up and settling state characteristics of the proposed linear actuator is investigated theoretically and experimentally, and is applicable to evaluate step resolution of the precision platform driven by the actuator. Moreover the structure of the two-degree position stage system is described and a special precision displacement measurement system is built. Finally, the characteristics of the two-degree position stage are studied. In the closed-loop condition the positioning accuracy of plus or minus <0.5 μm is experimentally obtained for the stage propelled by the piezoelectric motor. A precision position stage based the proposed butterfly-shaped linear piezoelectric is theoretically and experimentally investigated.

  3. Evaluating North America Paleoclimate Simulations for 6 ka and 21 ka Using a Combination of Observed Paleovegetation Data and Process-Based Vegetation Model Simulations

    NASA Astrophysics Data System (ADS)

    Shafer, S. L.; Bartlein, P. J.

    2015-12-01

    Paleoclimate model simulations are often evaluated using observed paleovegetation data (e.g., pollen and plant macrofossils) that record vegetation responses to past climate changes. These observed vegetation data can be combined with mechanistic vegetation model simulations to develop process-based evaluations of paleoclimate model simulations. The use of mechanistic vegetation model simulations allows us to identify the particular spatial and temporal features of individual paleoclimate simulations that may be producing agreement or disagreement between the observed and simulated vegetation data. We used this approach to evaluate a set of eight PMIP3 (Paleoclimate Modelling Intercomparison Project phase 3) paleoclimate simulations for 6 ka and 21 ka from the CMIP5 (Coupled Model Intercomparison Project phase 5) database. Climate data were regridded onto a 10-km grid of North America using the PMIP3 vegetation simulation protocol. The regridded climate data were used as input to BIOME4, an equilibrium vegetation model, to simulate 6 ka and 21 ka biomes across the study area. The simulated biome data were compared with observed paleovegetation data from the BIOME 6000 (version 4.2) dataset. In general, agreement between simulated and observed biomes was greater for forest biomes than for non-forest biomes. We evaluated specific instances of disagreement between the simulated and observed biomes to determine whether the biome disagreement was produced by the climate model simulation (e.g., temperature bias), the vegetation model simulation (e.g., inability to simulate important disturbance regimes), the observed paleovegetation data (e.g., limits in the biomization method), or a combination of these factors. The results are summarized and we describe some of the strengths and limitations of this data-model comparison approach for evaluating paleoclimate simulations.

  4. Linear phase compressive filter

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line.

  5. Linear phase compressive filter

    DOEpatents

    McEwan, T.E.

    1995-06-06

    A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line. 2 figs.

  6. A Ka-band radial relativistic backward wave oscillator with GW-class output power

    NASA Astrophysics Data System (ADS)

    Zhu, Jiaxin; Zhang, Xiaoping; Dang, Fangchao

    2016-07-01

    A novel radial relativistic backward wave oscillator with a reflector is proposed and designed to generate GW-level high power microwaves at Ka-band. The segmented radial slow wave structure and the reflector are matched to enhance interaction efficiency. We choose the volume wave TM01 mode as the working mode due to the volume wave characteristic. The main structural parameters of the novel device are optimized by particle-in-cell simulation. High power microwaves with power of 2 GW and a frequency of 29.4 GHz are generated with 30% efficiency when the electron beam voltage is 383 kV, the beam current is 17 kA, and the guiding magnetic field is only 0.6 T. Simultaneously, the highest electric field in the novel Ka-band device is just about 960 kV/cm in second slow wave structure.

  7. Radar altimetry backscattering signatures at Ka, Ku, C, and S bands over West Africa

    NASA Astrophysics Data System (ADS)

    Frappart, F.; Fatras, C.; Mougin, E.; Marieu, V.; Diepkilé, A. T.; Blarel, F.; Borderies, P.

    This study presents a comprehensive comparison of radar altimetry signatures at Ka-, Ku-, C-, and S-bands using SARAL, ENVISAT and Jason-2 data over the major bioclimatic zones, soil and vegetation types encountered in West-Africa, with an emphasis on the new information at Ka-band provided by the recently launched SARAL-Altika mission. Spatio-temporal variations of the radar altimetry responses were related to changes in surface roughness, land cover and soil wetness. Analysis of time series of backscattering coefficients along the West African bioclimatic gradient shows that radar echoes at nadir incidence are well correlated to soil moisture in semi-arid savannah environments. Radar altimeters are able to detect the presence of water even under a dense canopy cover at all frequencies. But only measurements at Ka-band are able to penetrate underneath the canopy of non-inundated tropical evergreen forests.

  8. NASA's K/Ka-Band Broadband Aeronautical Terminal for Duplex Satellite Video Communications

    NASA Technical Reports Server (NTRS)

    Densmore, A.; Agan, M.

    1994-01-01

    JPL has recently begun the development of a Broadband Aeronautical Terminal (BAT) for duplex video satellite communications on commercial or business class aircraft. The BAT is designed for use with NASA's K/Ka-band Advanced Communications Technology Satellite (ACTS). The BAT system will provide the systems and technology groundwork for an eventual commercial K/Ka-band aeronautical satellite communication system. With industry/government partnerships, three main goals will be addressed by the BAT task: 1) develop, characterize and demonstrate the performance of an ACTS based high data rate aeronautical communications system; 2) assess the performance of current video compression algorithms in an aeronautical satellite communication link; and 3) characterize the propagation effects of the K/Ka-band channel for aeronautical communications.

  9. Development of Methods for the Determination of pKa Values

    PubMed Central

    Reijenga, Jetse; van Hoof, Arno; van Loon, Antonie; Teunissen, Bram

    2013-01-01

    The acid dissociation constant (pKa) is among the most frequently used physicochemical parameters, and its determination is of interest to a wide range of research fields. We present a brief introduction on the conceptual development of pKa as a physical parameter and its relationship to the concept of the pH of a solution. This is followed by a general summary of the historical development and current state of the techniques of pKa determination and an attempt to develop insight into future developments. Fourteen methods of determining the acid dissociation constant are placed in context and are critically evaluated to make a fair comparison and to determine their applications in modern chemistry. Additionally, we have studied these techniques in light of present trends in science and technology and attempt to determine how these trends might affect future developments in the field. PMID:23997574

  10. Experiments on Tree Reflectivity at C, X, K and Ka-bands

    NASA Astrophysics Data System (ADS)

    Eskelinen, Pekka; Ylinen, Juhana

    2014-07-01

    Dedicated field portable radars have been used to measure the reflectivity of identified deciduous and coniferous trees at C to Ka frequency bands with perpendicular illumination. Actual test radars, their electrical parameters including antennas and calibration devices are described. First results show summer time reflectivities from -30 to -10 dB (m2/m2) for deciduous trees and from -30 to 0 dB (2/m2) for coniferous samples, depending on frequency band. Late autumn and spring measurements show particularly well in Ka-band the absence of leaves. Variations in histogram detail, from one frequency to another, exceed 10 dB despite the cumulative probabilities for all bands are quite similar. The measured power spectral density of deciduous trees in the spring was typically 20 dB/Hz at X-band and 30 dB/Hz in Ka-band. Midsummer tests gave values close to 15 and 25 dB/Hz.

  11. Validation of SARAL/AltiKa data in the Amazon basin

    NASA Astrophysics Data System (ADS)

    Santos da Silva, Joecila; Calmant, Stephane; Medeiros Moreira, Daniel; Oliveira, Robson; Conchy, Taina; Gennero, Marie-Claude; Seyler, Frederique

    2015-04-01

    SARAL/AltiKa is a link between past missions (since it flies on the ERS-ENVISAT orbit with Ku band nadir altimeters in LRM) and future missions such as SWOT's Ka band interferometry swaths. In the present study, we compare the capability of its altimeter AltiKa to that of previous missions working in the Ku band such as ENVISAT and Jason-2 in retrieving water levels over the Amazon basin. Same as for the aforementioned preceding missions, the best results were obtained with the ICE-1 retracking algorithm. We qualitatively analyze the impact of rainfalls in the loss of measurements. Since making long -multi mission- time series is of major importance either for hydro-climatic studies or for basin management, we also present an estimate of the altimeter bias in order that the SARAL series of water level can be appended to those of these previous missions.

  12. Pharmacokinetic drivers of toxicity for basic molecules: Strategy to lower pKa results in decreased tissue exposure and toxicity for a small molecule Met inhibitor

    SciTech Connect

    Diaz, Dolores; Ford, Kevin A.; Hartley, Dylan P.; Harstad, Eric B.; Cain, Gary R.; Achilles-Poon, Kirsten; Nguyen, Trung; Peng, Jing; Zheng, Zhong; Merchant, Mark; Sutherlin, Daniel P.; Gaudino, John J.; Kaus, Robert; Lewin-Koh, Sock C.; Choo, Edna F.; Liederer, Bianca M.; Dambach, Donna M.

    2013-01-01

    Several toxicities are clearly driven by free drug concentrations in plasma, such as toxicities related to on-target exaggerated pharmacology or off-target pharmacological activity associated with receptors, enzymes or ion channels. However, there are examples in which organ toxicities appear to correlate better with total drug concentrations in the target tissues, rather than with free drug concentrations in plasma. Here we present a case study in which a small molecule Met inhibitor, GEN-203, with significant liver and bone marrow toxicity in preclinical species was modified with the intention of increasing the safety margin. GEN-203 is a lipophilic weak base as demonstrated by its physicochemical and structural properties: high LogD (distribution coefficient) (4.3) and high measured pKa (7.45) due to the basic amine (N-ethyl-3-fluoro-4-aminopiperidine). The physicochemical properties of GEN-203 were hypothesized to drive the high distribution of this compound to tissues as evidenced by a moderately-high volume of distribution (Vd > 3 l/kg) in mouse and subsequent toxicities of the compound. Specifically, the basicity of GEN-203 was decreased through addition of a second fluorine in the 3-position of the aminopiperidine to yield GEN-890 (N-ethyl-3,3-difluoro-4-aminopiperidine), which decreased the volume of distribution of the compound in mouse (Vd = 1.0 l/kg), decreased its tissue drug concentrations and led to decreased toxicity in mice. This strategy suggests that when toxicity is driven by tissue drug concentrations, optimization of the physicochemical parameters that drive tissue distribution can result in decreased drug concentrations in tissues, resulting in lower toxicity and improved safety margins. -- Highlights: ► Lower pKa for a small molecule: reduced tissue drug levels and toxicity. ► New analysis tools to assess electrostatic effects and ionization are presented. ► Chemical and PK drivers of toxicity can be leveraged to improve safety.

  13. Ka-Band TWT High-Efficiency Power Combiner for High-Rate Data Transmission

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee; Vaden, Karl R.; Lesny, Gary G.; Glass, Jeffrey L.

    2007-01-01

    A four-port magic-T hybrid waveguide junction serves as the central component of a high-efficiency two-way power combiner circuit for transmitting a high-rate phase-modulated digital signal at a carrier frequency in the Ka-band (between 27 and 40 GHz). This power combiner was developed to satisfy a specific requirement to efficiently combine the coherent outputs of two traveling-wavetube (TWT) amplifiers that are typically characterized by power levels on the order of 100 W or more. In this application, the use of a waveguide-based power combiner (instead of a coaxial-cable- or microstrip-based power combiner, for example) is dictated by requirements for low loss, high power-handling capability, and broadband response. Combiner efficiencies were typically 90 percent or more over both the linear and saturated output power regions of operation of the TWTs . Figure 1 depicts the basic configuration of the magic-T hybrid junction. The coherent outputs of the two TWTs enter through ports 1 and 4. As a result of the orientations of the electromagnetic fields, which also provides a needed high port-to-port isolation, of these two input signals and the interior design of the magic-T junction, the input powers are divided so as to add in phase at one output port (port 2), and to be opposite in phase and hence cancel each other at the opposite coplanar output port (port 3). The net result is that the output power at port 2 is essentially double that of the output of one TWT, minus the power lost in the magic-T hybrid junction. Optimum performance as a high-efficiency power combiner thus requires a balance of both power and phase at the input ports of the magic-T. Replicas of this two-way combiner can be arranged in a binary configuration to obtain a 2n-way (where n is an integer) combiner. For example, Figure 2 illustrates the use of three two-way combiners to combine the outputs of four TWTs.

  14. Oil well pump driving unit

    SciTech Connect

    Gilbertson, T. A.

    1984-11-06

    An oil well pumping apparatus which includes a submerged reciprocating pump mounted in a tubing arrangement communicating with the wellhead, a sucker rod string extending through the tubing arrangement and connected in driving relation with the pump, and a pumping tee and stuffing box arrangement mounted on the casing of the well at the wellhead and including a sealed drive rod arrangement in the stuffing box connected in driving relation to said sucker rod string, and a pump driving unit. The pump driving unit includes a hydraulic cylinder and support means including a gimbal arrangement for supporting the hydraulic cylinder over the stuffing box with the axis of the cylinder rod aligned with the axis of said stuffing box. A coupling means is provided for coupling the cylinder rod to the sealed drive rod arrangement. A hydraulic drive/control unit is coupled to said in/out fluid line for operating cycle consisting of a hydraulic power upstroke and a gravity power downstroke. An assist cylinder and accumulator combination are provided to counteract part of the weight of the rod string and thus reduce the workload on t

  15. Oil well pump driving unit

    SciTech Connect

    Gilbertson, T.A.

    1982-03-23

    An oil well pumping apparatus which includes a submerged reciprocating pump mounted in a tubing arrangement communicating with the well head, a sucker rod string extending through the tubing arrangement and connected in driving relation with the pump, and a pumping tee and stuffing box arrangement mounted on the casing of the well at the well head and including a sealed drive rod arrangement in the stuffing box connected in driving relation to said sucker rod string, and a pump driving unit. The pump driving unit includes a hydraulic cylinder and support means for supporting the hydraulic cylinder over the stuffing box with the axis of the cylinder rod aligned with the axis of said stuffing box. A coupling means is provided for coupling the cylinder rod to the seal drive rod arrangement. A hydraulic drive -control unit is coupled to said in-out fluid line for operating the hydraulic cylinder to produce an operating cycle consisting of a hydraulic power upstroke and a gravity power downstroke.

  16. Electron Locking in Current Drive

    NASA Astrophysics Data System (ADS)

    McCollam, K. J.; Jarboe, T. R.; Nelson, B. A.; Orvis, D. J.; Raman, R.; Redd, A. J.; Smith, R. J.; Nagata, M.; Uyama, T.

    2000-10-01

    The traveling n=1, m~= q_edge magnetic distortion observed in the Helicity Injected Torus (HIT-II) during coaxial helicity injection (CHI) is responsible for some current profile relaxation. A model for electromotive current drive, called the electron locking model, can account for the results of current drive experiments in both the HIT-II and the original HIT devices. The most relevant of these results involve the the frequencies and directions of the mode itself, the E× B drift, and the electric current drift. In spherical tokamaks with CHI, electrode and coil polarities can be changed to control the relative directions of these drifts. Results from HIT-II experiments with different polarities are shown. These point out the character n=1, m~= q_edge mode, and suggest its role in CHI current drive. The electron locking model is presented, and is also discussed in the context of mean field electrodynamics. This model might also be applied to other types of current drive, such as rotating magnetic field (RMF) current drive, oscillating field current drive (OFCD), steady inductive helicity injection (SIHI), or Ohmic current drive in a reversed field pinch (RFP). These examples are discussed.

  17. Foucault Pendulum without Driving

    NASA Astrophysics Data System (ADS)

    Yamashita, Yoshifumi

    2016-06-01

    Foucault pendulums are two-dimensional harmonic oscillators to which the Coriolis force is applied. The Foucault parameter ΩF is the ideal rate of rotation of the plane of oscillation due to the Coriolis force. Kamerlingh Onnes pointed out that the actual behavior of Foucault pendulums can be understood only by taking into account the unavoidable mechanical asymmetry, i.e., the difference between the frequency in the X-direction and that in the Y-direction, which is called the asymmetry parameter δ. Our equations of motion for Foucault pendulums are linear and their solutions are easily obtained. We are interested in slowly varying rotations of the plane of oscillation, where the angle of rotation is denoted by φ. The motion of the bob consists of rapid simple oscillations and the slow rotations mentioned above. Eliminating the rapid oscillations, we obtain an analytic expression for tan 2φ, which is a periodic function with period π /√{Ω F2 + δ 2} . The graphs of the rotation φ versus time t have two distinct appearances. Under the condition ΩF ≥ δ|cos(2θ)| (θ is the initial value of φ), φ decreases monotonically, which is the behavior expected for Foucault pendulums. Otherwise φ repeatedly increases and decreases, which is the behavior of pendulums describing Lissajous figures. The vertical component of angular momentum is also calculated analytically.

  18. Design of a Ka-Band Propagation Terminal for Atmospheric Measurements in Polar Regions

    NASA Technical Reports Server (NTRS)

    Houts, Jacquelynne R.; Nessel, James A.; Zemba, Michael J.

    2016-01-01

    This paper describes the design and performance of a Ka-Band beacon receiver developed at NASA Glenn Research Center (GRC) that will be installed alongside an existing Ka-Band Radiometer [2] located at the east end of the Svalbard Near Earth Network (NEN) complex. The goal of this experiment is to characterize rain fade attenuation to improve the performance of existing statistical rain attenuation models. The ground terminal developed by NASA GRC utilizes an FFT-based frequency estimation [3] receiver capable of characterizing total path attenuation effects due to gaseous absorption, clouds, rain, and scintillation by directly measuring the propagated signal from the satellite Thor 7.

  19. Design of a Ka-band Propagation Terminal for Atmospheric Measurements in Polar Regions

    NASA Technical Reports Server (NTRS)

    Houts, Jacquelynne R.; Nessel, James A.; Zemba, Michael J.

    2016-01-01

    This paper describes the design and performance of a Ka-Band beacon receiver developed at NASA Glenn Research Center (GRC) that will be installed alongside an existing Ka-Band Radiometer located at the east end of the Svalbard Near Earth Network (NEN) complex. The goal of this experiment is to characterize rain fade attenuation to improve the performance of existing statistical rain attenuation models. The ground terminal developed by NASA GRC utilizes an FFT-based frequency estimation receiver capable of characterizing total path attenuation effects due to gaseous absorption, clouds, rain, and scintillation by directly measuring the propagated signal from the satellite Thor 7.

  20. Design characterization of an electronic steerable Ka-band antenna using liquid crystal phase shifters

    NASA Astrophysics Data System (ADS)

    Hoehn, A.; Hager, P. B.; Harder, J. T.

    Modern high data rate satellite communication systems increasingly utilize the Ka-band due to its ability to support higher bandwidth. Prior research work presented a copper-galvanically produced Ka-band horn array antenna and associated waveguide distribution network, mounted on a two axes mechanical steerable mechanism (LISAMS) for use aboard fast, low earth orbiting satellites. The current project, LISAES, investigates the feasibility of a similar horn array antenna, but fitted with liquid crystal phase shifters in the transmission path of each horn, which now allow steering of the antenna boresight through beam forming without the use of mechanically moving parts.

  1. A portfolio of fine resolution Ka-band SAR images : part l.

    SciTech Connect

    Thompson, Martin; Gutierrez, Vivian Dee; Dubbert, Dale Francis; Doerry, Armin Walter

    2005-03-01

    Sandia National Laboratories designs and builds Synthetic Aperture Radar (SAR) systems capable of forming high-quality exceptionally fine resolution images. During the spring of 2004 a series of test flights were completed with a Ka-band testbed SAR on Sandia's DeHavilland DHC-6 Twin Otter aircraft. A large data set was collected including real-time fine-resolution images of a variety of target scenes. This paper offers a sampling of high quality images representative of the output of Sandia's Ka-band testbed radar with resolutions as fine as 4 inches. Images will be annotated with descriptions of collection geometries and other relevant image parameters.

  2. First Results from an Airborne Ka-Band SAR Using SweepSAR and Digital Beamforming

    NASA Technical Reports Server (NTRS)

    Sadowy, Gregory A.; Ghaemi, Hirad; Hensley, Scott C.

    2012-01-01

    SweepSAR is a wide-swath synthetic aperture radar technique that is being studied for application on the future Earth science radar missions. This paper describes the design of an airborne radar demonstration that simulates an 11-m L-band (1.2-1.3 GHz) reflector geometry at Ka-band (35.6 GHz) using a 40-cm reflector. The Ka-band SweepSAR Demonstration system was flown on the NASA DC-8 airborne laboratory and used to study engineering performance trades and array calibration for SweepSAR configurations. We present an instrument and experiment overview, instrument calibration and first results.

  3. Driving Performance Under Alcohol in Simulated Representative Driving Tasks

    PubMed Central

    Kenntner-Mabiala, Ramona; Kaussner, Yvonne; Jagiellowicz-Kaufmann, Monika; Hoffmann, Sonja; Krüger, Hans-Peter

    2015-01-01

    Abstract Comparing drug-induced driving impairments with the effects of benchmark blood alcohol concentrations (BACs) is an approved approach to determine the clinical relevance of findings for traffic safety. The present study aimed to collect alcohol calibration data to validate findings of clinical trials that were derived from a representative test course in a dynamic driving simulator. The driving performance of 24 healthy volunteers under placebo and with 0.05% and 0.08% BACs was measured in a double-blind, randomized, crossover design. Trained investigators assessed the subjects’ driving performance and registered their driving errors. Various driving parameters that were recorded during the simulation were also analyzed. Generally, the participants performed worse on the test course (P < 0.05 for the investigators’ assessment) under the influence of alcohol. Consistent with the relevant literature, lane-keeping performance parameters were sensitive to the investigated BACs. There were significant differences between the alcohol and placebo conditions in most of the parameters analyzed. However, the total number of errors was the only parameter discriminating significantly between all three BAC conditions. In conclusion, data show that the present experimental setup is suitable for future psychopharmacological research. Thereby, for each drug to be investigated, we recommend to assess a profile of various parameters that address different levels of driving. On the basis of this performance profile, the total number of driving errors is recommended as the primary endpoint. However, this overall endpoint should be completed by a specifically sensitive parameter that is chosen depending on the effect known to be induced by the tested drug. PMID:25689289

  4. Magnetic compression laser driving circuit

    DOEpatents

    Ball, Don G.; Birx, Dan; Cook, Edward G.

    1993-01-01

    A magnetic compression laser driving circuit is disclosed. The magnetic compression laser driving circuit compresses voltage pulses in the range of 1.5 microseconds at 20 Kilovolts of amplitude to pulses in the range of 40 nanoseconds and 60 Kilovolts of amplitude. The magnetic compression laser driving circuit includes a multi-stage magnetic switch where the last stage includes a switch having at least two turns which has larger saturated inductance with less core material so that the efficiency of the circuit and hence the laser is increased.

  5. Magnetic compression laser driving circuit

    DOEpatents

    Ball, D.G.; Birx, D.; Cook, E.G.

    1993-01-05

    A magnetic compression laser driving circuit is disclosed. The magnetic compression laser driving circuit compresses voltage pulses in the range of 1.5 microseconds at 20 kilovolts of amplitude to pulses in the range of 40 nanoseconds and 60 kilovolts of amplitude. The magnetic compression laser driving circuit includes a multi-stage magnetic switch where the last stage includes a switch having at least two turns which has larger saturated inductance with less core material so that the efficiency of the circuit and hence the laser is increased.

  6. Linearly polarized fiber amplifier

    SciTech Connect

    Kliner, Dahv A.; Koplow, Jeffery P.

    2004-11-30

    Optically pumped rare-earth-doped polarizing fibers exhibit significantly higher gain for one linear polarization state than for the orthogonal state. Such a fiber can be used to construct a single-polarization fiber laser, amplifier, or amplified-spontaneous-emission (ASE) source without the need for additional optical components to obtain stable, linearly polarized operation.

  7. SLAC Linear Collider

    SciTech Connect

    Richter, B.

    1985-12-01

    A report is given on the goals and progress of the SLAC Linear Collider. The status of the machine and the detectors are discussed and an overview is given of the physics which can be done at this new facility. Some ideas on how (and why) large linear colliders of the future should be built are given.

  8. Linear force device

    NASA Technical Reports Server (NTRS)

    Clancy, John P.

    1988-01-01

    The object of the invention is to provide a mechanical force actuator which is lightweight and manipulatable and utilizes linear motion for push or pull forces while maintaining a constant overall length. The mechanical force producing mechanism comprises a linear actuator mechanism and a linear motion shaft mounted parallel to one another. The linear motion shaft is connected to a stationary or fixed housing and to a movable housing where the movable housing is mechanically actuated through actuator mechanism by either manual means or motor means. The housings are adapted to releasably receive a variety of jaw or pulling elements adapted for clamping or prying action. The stationary housing is adapted to be pivotally mounted to permit an angular position of the housing to allow the tool to adapt to skewed interfaces. The actuator mechanisms is operated by a gear train to obtain linear motion of the actuator mechanism.

  9. Linear models: permutation methods

    USGS Publications Warehouse

    Cade, B.S.; Everitt, B.S.; Howell, D.C.

    2005-01-01

    Permutation tests (see Permutation Based Inference) for the linear model have applications in behavioral studies when traditional parametric assumptions about the error term in a linear model are not tenable. Improved validity of Type I error rates can be achieved with properly constructed permutation tests. Perhaps more importantly, increased statistical power, improved robustness to effects of outliers, and detection of alternative distributional differences can be achieved by coupling permutation inference with alternative linear model estimators. For example, it is well-known that estimates of the mean in linear model are extremely sensitive to even a single outlying value of the dependent variable compared to estimates of the median [7, 19]. Traditionally, linear modeling focused on estimating changes in the center of distributions (means or medians). However, quantile regression allows distributional changes to be estimated in all or any selected part of a distribution or responses, providing a more complete statistical picture that has relevance to many biological questions [6]...

  10. Dopaminergic Circuitry Underlying Mating Drive.

    PubMed

    Zhang, Stephen X; Rogulja, Dragana; Crickmore, Michael A

    2016-07-01

    We develop a new system for studying how innate drives are tuned to reflect current physiological needs and capacities, and how they affect sensory-motor processing. We demonstrate the existence of male mating drive in Drosophila, which is transiently and cumulatively reduced as reproductive capacity is depleted by copulations. Dopaminergic activity in the anterior of the superior medial protocerebrum (SMPa) is also transiently and cumulatively reduced in response to matings and serves as a functional neuronal correlate of mating drive. The dopamine signal is transmitted through the D1-like DopR2 receptor to P1 neurons, which also integrate sensory information relevant to the perception of females, and which project to courtship motor centers that initiate and maintain courtship behavior. Mating drive therefore converges with sensory information from the female at the point of transition to motor output, controlling the propensity of a sensory percept to trigger goal-directed behavior. PMID:27292538

  11. Distracted Driving Raises Crash Risk

    MedlinePlus

    ... Raises Crash Risk Video technology and in-vehicle sensors showed that distracted driving, especially among new drivers, ... whenever the cars were moving. A suite of sensors recorded acceleration, sudden braking or swerving, and other ...

  12. Driving Speed vs Fuel Efficiency.

    ERIC Educational Resources Information Center

    Vest, Floyd

    1980-01-01

    A mathematical treatment of the relationship between driving speed and fuel efficiency is presented. The material involves applications of exponentials, logarithms, and elementary calculus, and is intended to be enrichment material for secondary and lower college mathematics classes. (MP)

  13. Dangers of Texting While Driving

    MedlinePlus

    ... laws Currently there is no national ban on texting or using a wireless phone while driving, but a number of states have passed laws banning texting or wireless phones or requiring hands-free use ...

  14. Warp drive with zero expansion

    NASA Astrophysics Data System (ADS)

    Natário, José

    2002-03-01

    It is commonly believed that Alcubierre's warp drive works by contracting space in front of the warp bubble and expanding the space behind it. We show that this contraction/expansion is but a marginal consequence of the choice made by Alcubierre and explicitly construct a similar spacetime where no contraction/expansion occurs. Global and optical properties of warp-drive spacetimes are also discussed.

  15. Mechanical drive for blood pump

    DOEpatents

    Bifano, N.J.; Pouchot, W.D.

    1975-07-29

    This patent relates to a highly efficient blood pump to be used as a replacement for a ventricle of the human heart to restore people disabled by heart disease. The mechanical drive of the present invention is designed to operate in conjunction with a thermoelectric converter power source. The mechanical drive system essentially converts the output of a rotary power into pulsatile motion so that the power demand from the thermoelectric converter remains essentially constant while the blood pump output is pulsed. (auth)

  16. Distracted driving: a neglected epidemic.

    PubMed

    Dildy, Dale W

    2012-10-01

    In 2009, the National Highway Traffic Safety Administration (NHTSA) estimated nearly 6,000 distracted driver fatalities and 515,000 injuries in the United States alone. Distracted driving is a worldwide problem that needs to be addressed. Software is available to disable cell phone usage while driving, but using the advanced technology may require legislation along with a renewed sense of driver responsibility. PMID:23061239

  17. A drive for all users

    SciTech Connect

    Drury, W.; Satya, T.

    1995-12-31

    The forces of industrial automation and efficiency, both in terms of process capability and energy, continue to fuel the rapid growth in the market for electrical variable speed drives. This demand coupled with the need for improved performance and the inevitable consequence of growth, results in a fiercely competitive market place. Within such an environment the claim of ``A drive for all users`` is not new, and those with some knowledge of the drives industry will consider any such claim with great skepticism. The literature on drives is littered with industrialists, and more than a few academics, claiming to have the ultimate drive, the optimum for each and every application. This situation is particularly true in the case of AC drive technology. The documented battles between proponents of current source verses PWM voltage source, not to mention the quest for the ultimate PWM strategy, have resulted in substantial deforestation of the planet. This paper makes no such unqualified claim rather it describes a very substantial and significant step towards such a eutopia.

  18. Low backlash direct drive actuator

    DOEpatents

    Kuklo, T.C.

    1994-10-25

    A low backlash direct drive actuator is described which comprises a motor such as a stepper motor having at least 200 steps per revolution; a two part hub assembly comprising a drive hub coaxially attached to the shaft of the motor and having a plurality of drive pins; a driven hub having a plurality of bores in one end thereof in alignment with the drive pins in the drive hub and a threaded shaft coaxially mounted in an opposite end of the driven hub; and a housing having a central bore therein into which are fitted the drive hub and driven hub, the housing having a motor mount on one end thereof to which is mounted the stepper motor, and a closed end portion with a threaded opening therein coaxial with the central bore in the housing and receiving therein the threaded shaft attached to the driven hub. Limit switches mounted to the housing cooperate with an enlarged lip on the driven hub to limit the lateral travel of the driven hub in the housing, which also acts to limit the lateral travel of the threaded shaft which functions as a lead screw. 10 figs.

  19. Low backlash direct drive actuator

    DOEpatents

    Kuklo, Thomas C.

    1994-01-01

    A low backlash direct drive actuator is described which comprises a motor such as a stepper motor having at least 200 steps per revolution; a two part hub assembly comprising a drive hub coaxially attached to the shaft of the motor and having a plurality of drive pins; a driven hub having a plurality of bores in one end thereof in alignment with the drive pins in the drive hub and a threaded shaft coaxially mounted in an opposite end of the driven hub; and a housing having a central bore therein into which are fitted the drive hub and driven hub, the housing having a motor mount on one end thereof to which is mounted the stepper motor, and a closed end portion with a threaded opening therein coaxial with the central bore in the housing and receiving therein the threaded shaft attached to the driven hub. Limit switches mounted to the housing cooperate with an enlarged lip on the driven hub to limit the lateral travel of the driven hub in the housing, which also acts to limit the lateral travel of the threaded shaft which functions as a lead screw.

  20. Shortcuts to adiabaticity from linear response theory

    SciTech Connect

    Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian

    2015-10-23

    A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts to adiabaticity for specific and very short driving times.

  1. Shortcuts to adiabaticity from linear response theory

    DOE PAGES

    Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian

    2015-10-23

    A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts tomore » adiabaticity for specific and very short driving times.« less

  2. Conceptual Design of the Drive Beam for a PWFA-LC

    SciTech Connect

    Pei, S.; Hogan, M.J.; Raubenheimer, T.O.; Seryi, A.; Braun, H.H.; Corsini, R.; Delahaye, J.P.; /DESY

    2009-08-03

    Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for bunch with triangular shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective than the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed by the PWFA collaboration. Here we will describe the conceptual design and optimization of the drive beam, which includes the drive beam linac and distribution system. We apply experience of the CLIC drive beam design and demonstration in the CLIC Test Facility (CTF3) to this study. We discuss parameter optimization of the drive beam linac structure and evaluate the drive linac efficiency in terms of the drive beam distribution scheme and the klystron/modulator requirements.

  3. A dual-cavity ruby maser for the Ka-band link experiment

    NASA Technical Reports Server (NTRS)

    Shell, J.; Quinn, R. B.

    1994-01-01

    A 33.68-GHz dual-cavity ruby maser was built to support the Ka-Band Link Experiment (KABLE) conducted with the Mars Observer spacecraft. It has 25 dB of net gain and a 3-dB bandwidth of 85 MHz. Its noise temperature in reference to the cooled feedhorn aperture is 5 K.

  4. Design of a Ka-band gyro-TWT amplifier for broadband operation

    SciTech Connect

    Alaria, Mukesh Kumar; Sinha, A. K.; Choyal, Y.

    2013-07-15

    In this paper, the design of a Ka-band periodically ceramic loaded gyro-TWT amplifier has been carried out. The design predict that the interaction structure can produce more than 80 kW output power, 50 dB saturated gain, and 3 dB bandwidth for 65 kV and 5 A electron beam with velocity ratio (α) of 1.2. This paper describes the design and simulation of a high performance 35 GHz TE{sub 01} mode gyro-TWT that applies the same technique of employing a periodic dielectric loaded interaction structure to achieve stability and wide bandwidth. The design of input coupler with loaded interaction structure for Ka-band Gyro-TWT has been carried out using Ansoft hfss. The return loss (S{sub 11}) and transmission loss (S{sub 21}) of the Ka-band gyro-TWT input coupler have been found to be −27.3 dB and −0.05 dB, respectively. The design of output window for Ka-band Gyro-TWT has been carried out using cst microwave studio.

  5. Design of a Ka-band gyro-TWT amplifier for broadband operation

    NASA Astrophysics Data System (ADS)

    Alaria, Mukesh Kumar; Choyal, Y.; Sinha, A. K.

    2013-07-01

    In this paper, the design of a Ka-band periodically ceramic loaded gyro-TWT amplifier has been carried out. The design predict that the interaction structure can produce more than 80 kW output power, 50 dB saturated gain, and 3 dB bandwidth for 65 kV and 5 A electron beam with velocity ratio (α) of 1.2. This paper describes the design and simulation of a high performance 35 GHz TE01 mode gyro-TWT that applies the same technique of employing a periodic dielectric loaded interaction structure to achieve stability and wide bandwidth. The design of input coupler with loaded interaction structure for Ka-band Gyro-TWT has been carried out using Ansoft hfss. The return loss (S11) and transmission loss (S21) of the Ka-band gyro-TWT input coupler have been found to be -27.3 dB and -0.05 dB, respectively. The design of output window for Ka-band Gyro-TWT has been carried out using cst microwave studio.

  6. Performance of a Ka-band satellite system under variable transmitted signal power conditions

    NASA Technical Reports Server (NTRS)

    Fujikawa, Gene; Kerczewski, Robert J.

    1987-01-01

    A laboratory hardware-based satellite communication system simulator has been used to measure the effects of transmitted signal power changes on the performance of a Ka-band system. Such power changes can be used to compensate for signal fade due to rain attenuation. This paper presents and discusses the results of these measurements.

  7. Results from Two Years of Ka-Band Propagation Characterization at Svalbard, Norway

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Morse, Jacquelynne Rose; Zemba, Michael

    2014-01-01

    Over the several years, NASA plans to launch several earth science missions which are expected to achieve data throughputs of 5-40 terabits per day transmitted from low earth orbiting spacecraft to ground stations. The current S-band and X-band frequency allocations in use by NASA, however, are incapable of supporting the data rates required to meet this demand. As such, NASA is in the planning stages to upgrade its existing Near Earth Network (NEN) Polar ground stations to support Ka-band (25.5-27 GHz) operations. Consequently, it becomes imperative that characterization of propagation effects at these NEN sites is conducted to determine expected system performance, particularly at low elevation angles ((is) less than 10 deg) where spacecraft signal acquisition typically occurs. Since May 2011, NASA Glenn Research Center has installed and operated a Ka-band radiometer at the NEN site located in Svalbard, Norway. The Ka-band radiometer monitors the water vapor line, as well as 6 frequencies around 26.5 GHz at multiple elevation angles: 45 deg, 20 deg, and 10 deg. Two year data collection results indicate comparable performance to previously characterized northern latitude sites in the United States, i.e., Fairbanks, Alaska. It is observed that cloud cover at the Svalbard site remains the dominant loss mechanism for Ka-band links, resulting in a margin requirement of 4.1 dB to maintain link availability of 99% at 10 deg elevation.

  8. KA1-targeted regulatory domain mutations activate Chk1 in the absence of DNA damage.

    PubMed

    Gong, Eun-Yeung; Smits, Veronique A J; Fumagallo, Felipe; Piscitello, Desiree; Morrice, Nick; Freire, Raimundo; Gillespie, David A

    2015-01-01

    The Chk1 protein kinase is activated in response to DNA damage through ATR-mediated phosphorylation at multiple serine-glutamine (SQ) residues within the C-terminal regulatory domain, however the molecular mechanism is not understood. Modelling indicates a high probability that this region of Chk1 contains a kinase-associated 1 (KA1) domain, a small, compact protein fold found in multiple protein kinases including SOS2, AMPK and MARK3. We introduced mutations into Chk1 designed to disrupt specific structural elements of the predicted KA1 domain. Remarkably, six of seven Chk1 KA1 mutants exhibit constitutive biological activity (Chk1-CA) in the absence of DNA damage, profoundly arresting cells in G2 phase of the cell cycle. Cell cycle arrest induced by selected Chk1-CA mutants depends on kinase catalytic activity, which is increased several-fold compared to wild-type, however phosphorylation of the key ATR regulatory site serine 345 (S345) is not required. Thus, mutations targeting the putative Chk1 KA1 domain confer constitutive biological activity by circumventing the need for ATR-mediated positive regulatory phosphorylation. PMID:26039276

  9. An integrated Ka/Ku-band payload for personal, mobile and private business communications

    NASA Technical Reports Server (NTRS)

    Hayes, Edward J.; Keelty, J. Malcolm

    1991-01-01

    The Canadian Department of Communications has been studying options for a government-sponsored demonstration payload to be launched before the end of the century. A summary of the proposed system concepts and network architectures for providing an advanced private business network service at Ku-band and personal and mobile communications at Ka-band is presented. The system aspects addressed include coverage patterns, traffic capacity, and grade of service, multiple access options as well as special problems, such as Doppler in mobile applications. Earth terminal types and the advanced payload concept proposed in a feasibility study for the demonstration mission are described. This concept is a combined Ka-band/Ku-band payload which incorporates a number of advanced satellite technologies including a group demodulator to convert single-channel-per-carrier frequency division multiple access uplink signals to a time division multiplex downlink, on-board signal regeneration, and baseband switching to support packet switched data operation. The on-board processing capability of the payload provides a hubless VSAT architecture which permits single-hop full mesh interconnectivity. The Ka-band and Ku-band portions of the payload are fully integrated through an on-board switch, thereby providing the capability for fully integrated services, such as using the Ku-band VSAT terminals as gateway stations for the Ka-band personal and mobile communications services.

  10. Computer Aided Design of Ka-Band Waveguide Power Combining Architectures for Interplanetary Spacecraft

    NASA Technical Reports Server (NTRS)

    Vaden, Karl R.

    2006-01-01

    Communication systems for future NASA interplanetary spacecraft require transmitter power ranging from several hundred watts to kilowatts. Several hybrid junctions are considered as elements within a corporate combining architecture for high power Ka-band space traveling-wave tube amplifiers (TWTAs). This report presents the simulated transmission characteristics of several hybrid junctions designed for a low loss, high power waveguide based power combiner.

  11. Design and Evaluation of 275 kV-3 kA HTS Power Cable

    NASA Astrophysics Data System (ADS)

    Yagi, M.; Mukoyama, S.; Mitsuhashi, T.; Jun, T.; Liu, J.; Nakayama, R.; Hayakawa, N.; Wang, X.; Ishiyama, A.; Amemiya, N.; Hasegawa, T.; Saitoh, T.; Ohkuma, T.; Maruyama, O.

    A 275 kV 3 kA high temperature superconducting (HTS) cable has been developed in the Materials & Power Applications of Coated Conductors (M-PACC) project. The cable is expected to be put to practical use as the backbone power line in the future because the capacity of 1.5 GW is about the same as overhead transmission lines. The 30 m cable has been designed on the basis of design values that had been obtained by various voltage tests, AC loss measurement tests, short circuit tests, and other elementary tests. Cable insulation was determined by the design stresses and test conditions based on IEC, JEC (Japan electrical standards), and other HTS demonstrations. This cable was also designed to withstand the short circuit test of 63 kA for 0.6 seconds and to have low losses, including AC loss and dielectric loss of 0.8 W/m at 3kA, 275 kV. Based on the design, a 30 m cable was manufactured, and short samples during this manufacturing process were confirmed to have the designed characteristics. Furukawa Electric prepared a demonstration of the 30 m cable with two terminations and a cable joint. The long-term test under a current of 3 kA, and test voltage determined from 30 years of insulation degradation has been conducted since November 2012 at Shenyang in China.

  12. Progress of 275 kV-3 kA YBCO HTS cable

    NASA Astrophysics Data System (ADS)

    Yagi, M.; Mukoyama, S.; Amemiya, N.; Ishiyama, A.; Wang, X.; Aoki, Y.; Saito, T.; Ohkuma, T.; Maruyama, O.

    2011-11-01

    A 275 kV-3 kA high temperature superconducting (HTS) cable has been developed in the Materials & Power Applications of Coated Conductors (M-PACC) project. AC loss reduction of a two-layer HTS conductor was undertaken by removing the edges of YBCO tapes with low critical current density. The HTS conductor using these tapes was fabricated, and low loss of 0.235 W/m at 3 kA rms was achieved. The 275 kV-3 kA cable was designed, and the 2 m model cables were fabricated. This cable had 325 mm 2 copper stranded former inside the HTS conductor and a 310 mm 2 copper shield layer on the HTS shield layer for over-current protection. These cables withstood an over-current of 63.0 kA for 0.6 s, which is the worst situation for 275 kV systems. The partial discharge (PD) and V- t characteristics of a liquid nitrogen (LN 2)/polypropylene (PP) laminated paper composite insulation system have been integrated into the design of the insulation for the 275 kV cable. The results revealed that the PD inception stress (PDIE) did not depend on the insulation thickness, and that lifetime indices of V- t characteristics at PD inception were as high as about 80-100.

  13. Ka-Band, RF MEMS Switches on CMOS Grade Silicon with a Polyimide Interface Layer

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Varaljay, Nicholas C.; Papapolymerou, John

    2003-01-01

    For the first time, RF MEMS switcbes on CMOS grade Si witb a polyimide interface layer are fabricated and characterized. At Ka-Band (36.6 GHz), an insertion loss of 0.52 dB and an isolation of 20 dB is obtained.

  14. High Power High Efficiency Ka-Band Power Combiners for Solid-State Devices

    NASA Technical Reports Server (NTRS)

    Freeman, Jon C.; Wintucky, Edwin G.; Chevalier, Christine T.

    2006-01-01

    Wide-band power combining units for Ka-band are simulated for use as MMIC amplifier applications. Short-slot couplers as well as magic-tees are the basic elements for the combiners. Wide bandwidth (5 GHz) and low insertion (approx.0.2 dB) and high combining efficiencies (approx.90 percent) are obtained.

  15. Performance evolution of 60 kA HTS cable prototypes in the EDIPO test facility

    NASA Astrophysics Data System (ADS)

    Bykovsky, N.; Uglietti, D.; Sedlak, K.; Stepanov, B.; Wesche, R.; Bruzzone, P.

    2016-08-01

    During the first test campaign of the 60 kA HTS cable prototypes in the EDIPO test facility, the feasibility of a novel HTS fusion cable concept proposed at the EPFL Swiss Plasma Center (SPC) was successfully demonstrated. While the measured DC performance of the prototypes at magnetic fields from 8 T to 12 T and for currents from 30 kA to 70 kA was close to the expected one, an initial electromagnetic cycling test (1000 cycles) revealed progressive degradation of the performance in both the SuperPower and SuperOx conductors. Aiming to understand the reasons for the degradation, additional cycling (1000 cycles) and warm up-cool down tests were performed during the second test campaign. I c performance degradation of the SuperOx conductor reached ∼20% after about 2000 cycles, which was reason to continue with a visual inspection of the conductor and further tests at 77 K. AC tests were carried out at 0 and 2 T background fields without transport current and at 10 T/50 kA operating conditions. Results obtained in DC and AC tests of the second test campaign are presented and compared with appropriate data published recently. Concluding the first iteration of the HTS cable development program at SPC, a summary and recommendations for the next activity within the HTS fusion cable project are also reported.

  16. Theoretical study of firefly luciferin pKa values--relative absorption intensity in aqueous solutions.

    PubMed

    Hiyama, Miyabi; Akiyama, Hidefumi; Yamada, Kenta; Koga, Nobuaki

    2013-01-01

    Ground-state vibrational analyses of firefly luciferin and its conjugate acids and bases are performed. The Gibbs free energies obtained from these analyses are used to estimate pKa values for phenolic hydroxy and carboxy groups and the N-H(+) bond in the N-protonated thiazoline or benzothiazole ring of firefly luciferin. The theoretical pKa values are corrected using the experimental values. The concentrations of these chemical species in solutions with different pH values are estimated from their corrected pKa values, and the pH dependence of their relative absorption intensities is elucidated. With the results obtained we assign the experimental spectra unequivocally. Especially, the small peak near 400 nm at pH 1-2 in experimental absorption spectra is clarified to be due to the excitation of carboxylate anion with N-protonated thiazoline ring of firefly luciferin. Our results show that the pKa values of chemical species, which are contained in the aqueous solutions, are effective to assign experimental absorption spectra. PMID:23360188

  17. Determination of pKa values for deprotonable nucleobases in short model oligonucleotides.

    PubMed

    González-Olvera, Julio C; Martínez-Reyes, José; González-Jasso, Eva; Pless, Reynaldo C

    2015-11-01

    The deprotonation of ionizable nucleobases centrally placed in short model oligonucleotides was examined under different physical conditions, using UV absorption spectroscopy. The oligonucleotide sequences were designed so that only the central base would be ionized over the pH range examined. pKa values of 9.90±0.01 and 9.34±0.04 were determined for the guanine group in the oligomer d-ACAGCAC and 2'-deoxyguanosine, respectively, both at 25°C and 0.1M NaCl. Lengthening the oligonucleotide up to the tridecamer stage further increases the pKa of the central guanine moiety. Electrolyte concentration, temperature, and mixed water-ethanol solvents affect the acidity of the central base. Changes in the sequence surrounding the central guanine can also have a significant effect, especially in the case of strongly stacking sequences. The pKa values were also determined for the hepta(2'-O-methyl)ribonucleotide and the heptamer PNA of identical sequence, as well as for oligodeoxyribonucleotides with different deprotonable bases, viz. thymine, uracil, or hypoxanthine, in the central position. The results are interpreted in terms of the electric-field effect exerted on the departing proton by the negative electric charges located on the internucleotide phosphate groups, and calculations show this effect to approximately explain the magnitude of the pKa difference observed between the deoxyriboheptanucleotide and its electroneutral PNA analogue. PMID:26188860

  18. The Ka Values of Water and the Hydronium Ion for Comparison with Other Acids.

    ERIC Educational Resources Information Center

    Campbell, Mark L.; Waite, Boyd A.

    1990-01-01

    Provided is a rebuttal to an argument concerning the use of Ka values for water and the hydronium ion. The derivation of new values as a result of the treatment of the water as the solvent and using a Raoult's Law standard state is discussed. (CW)

  19. A circularly polarized Ka-band stacked patch antenna with increased gain

    NASA Technical Reports Server (NTRS)

    Zawadzki, M.

    2002-01-01

    Stacking layers of microstrip patches is a technique often used to improve the bandwidth of a patch antenna, but rarely used to increase its gain. The work presented here scales the three-layer S-band work done in to Ka-band.

  20. Theoretical study of firefly luciferin pKa values--relative absorption intensity in aqueous solutions.

    PubMed

    Hiyama, Miyabi; Akiyama, Hidefumi; Yamada, Kenta; Koga, Nobuaki

    2013-01-01

    Ground-state vibrational analyses of firefly luciferin and its conjugate acids and bases are performed. The Gibbs free energies obtained from these analyses are used to estimate pKa values for phenolic hydroxy and carboxy groups and the N-H(+) bond in the N-protonated thiazoline or benzothiazole ring of firefly luciferin. The theoretical pKa values are corrected using the experimental values. The concentrations of these chemical species in solutions with different pH values are estimated from their corrected pKa values, and the pH dependence of their relative absorption intensities is elucidated. With the results obtained we assign the experimental spectra unequivocally. Especially, the small peak near 400 nm at pH 1-2 in experimental absorption spectra is clarified to be due to the excitation of carboxylate anion with N-protonated thiazoline ring of firefly luciferin. Our results show that the pKa values of chemical species, which are contained in the aqueous solutions, are effective to assign experimental absorption spectra.

  1. Ka-Band High-Rate Telemetry System Upgrade for the NASA Deep Space Network

    NASA Technical Reports Server (NTRS)

    LaBelle, Remi; Bernardo, Abner; Bowen, James; Britcliffe, Michael; Bucknam, Neil; Link, Christopher; Long, Ezra; Manalo, Leslie; O'Dea, James A.; Rochblatt, David; Sosnowski, John; Veruttipong, Watt

    2009-01-01

    The NASA Deep Space Network (DSN) has a new requirement to support high-data-rate Category A (Cat A) missions (within 2 million kilometers of Earth) with simultaneous S-band uplink, S-band downlink and Ka-band downlink. The S-band links are required for traditional TT&C (Telemetry, Tracking, and Command) support to the spacecraft, while the Ka-band link is intended for high-data-rate science returns. The new Ka-band system combines the use of proven DSN cryogenic designs, for low system temperature, and high data rate capability using commercial telemetry receivers. The initial Cat A support is required for the James Webb Space Telescope (JWST) in 2013 and possibly other missions. The upgrade has been implemented into 3 different 34-meter Beam Waveguide (BWG) antennas in the DSN, one at each of the complexes in Canberra (Australia), Goldstone (California) and Madrid (Spain). System test data is presented to show that the requirements were met and the DSN is ready for Cat A Ka-band operational support.

  2. Linear magnetic bearing

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1983-01-01

    A linear magnetic bearing system having electromagnetic vernier flux paths in shunt relation with permanent magnets, so that the vernier flux does not traverse the permanent magnet, is described. Novelty is believed to reside in providing a linear magnetic bearing having electromagnetic flux paths that bypass high reluctance permanent magnets. Particular novelty is believed to reside in providing a linear magnetic bearing with a pair of axially spaced elements having electromagnets for establishing vernier x and y axis control. The magnetic bearing system has possible use in connection with a long life reciprocating cryogenic refrigerator that may be used on the space shuttle.

  3. Inversion for the driving forces of plate tectonics

    NASA Technical Reports Server (NTRS)

    Richardson, R. M.

    1983-01-01

    Inverse modeling techniques have been applied to the problem of determining the roles of various forces that may drive and resist plate tectonic motions. Separate linear inverse problems have been solved to find the best fitting pole of rotation for finite element grid point velocities and to find the best combination of force models to fit the observed relative plate velocities for the earth's twelve major plates using the generalized inverse operator. Variance-covariance data on plate motion have also been included. Results emphasize the relative importance of ridge push forces in the driving mechanism. Convergent margin forces are smaller by at least a factor of two, and perhaps by as much as a factor of twenty. Slab pull, apparently, is poorly transmitted to the surface plate as a driving force. Drag forces at the base of the plate are smaller than ridge push forces, although the sign of the force remains in question.

  4. Variational scheme towards an optimal lifting drive in fluid adhesion.

    PubMed

    Dias, Eduardo O; Miranda, José A

    2012-10-01

    One way of determining the adhesive strength of liquids is provided by a probe-tack test, which measures the force or energy required to pull apart two parallel flat plates separated by a thin fluid film. The vast majority of the existing theoretical and experimental works in fluid adhesion use very viscous fluids, and consider a linear drive L(t)∼Vt with constant lifting plate velocity V. This implies a given energy cost and large lifting force magnitude. One challenging question in this field pertains to what would be the optimal time-dependent drive Lopt(t) for which the adhesion energy would be minimized. We use a variational scheme to systematically search for such Lopt(t). By employing an optimal lifting drive, in addition to saving energy, we verify a significant decrease in the adhesion force peak. The effectiveness of the proposed lifting procedure is checked for both Newtonian and power-law fluids.

  5. Tephra record from the Sea of Marmara for the last 70 ka and its paleoceanographic implications

    NASA Astrophysics Data System (ADS)

    Cagatay, M.; Wulf, S.; Guichard, F.; Ozmaral, A.; Sancar; Akçer-Ön, S.; Henry, P.; Gasperini, L.

    2013-12-01

    Sea of Marmara (SoM) is a gateway between the Mediterraean and Black seas, and a tectonically active basin located on a transform plate boundary. Tephra record in the SoM is therefore very important for dating palaeoceanographic, paleoclimatic and tectonic events. We report three tephra units in cores from the SoM extending back to ca 70 ka BP and including an upper marine and a lower lacustrine units separated by a 12 ka (uncalib.) boundary. The uppermost tephra unit is up to 8 mm thick layer in the marine unit. It is heterogenous phonolitic with high total alkali content of 12.4-15.7 wt % and K2O/Na2O of 0.9 to 1.2. The middle and lower tephra layers occur in the lacustrine unit in ca 29 m-long Core MD-01-2430. The middle tephra (MT-1) is a 70 mm-thick homogeneously rhyolitic layer. The lower tephra (MT-2) is 140 mm thick and has a phonolitic-trachytic composition with CaO content of 1.7-1.9 wt % and bimodal K2O/Na2O of 1.0-1.4. Using their geochemical composition and stratigraphic analysis, we assign the tephra units, from top to bottom, to Vesuvius AP2 Pumice, Santorini Cape Riva and Campanian Ignimbrite, which have been previously dated at 3.5 ka BP, 21.95 ka BP, and 39.3 ka BP (all calender ka). The continuous sedimentary record in the Core MD-01-2430 covering the last ca 70 ka indicates that the SoM was lacustrine, disconnected from the Mediterraean Sea during MIS4, MIS3 and most of MIS2. This implies that the sill depth of the Çanakkale Strait (Dardanelles) was shallower than the present-day -65 m sill depth during MIS3 and MIS4. Figure 1: Morphotectonic map of the Sea of Marmara showing location of the studied cores (red stars). Figure 2: Geochemical biplots of tephra glass composition. a) Total alkali silica diagram b) FeO versus total alkalies for allocating cryptotephras from core MNTKS34 and ML01 to the AP2 tephra from Vesuvius. c) FeO versus CaO for correlating tephra MT1 with the Y-2 tephra from Santorini. d) SiO2 versus CaO for discriminating the

  6. Tephrostratigraphy of the last 170 ka in sedimentary successions from the Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Calanchi, Natale; Dinelli, Enrico

    2008-10-01

    In this study are discussed new SEM-EDS analyses performed on glass shards from five cores collected in the Central Adriatic Sea and two cores recovered from the South Adriatic Sea. A total of 26 tephra layers have been characterized and compared with the geochemical features of terrestrial deposits and other tephra archives in the area (South Adriatic Sea and Lago Grande di Monticchio, Vulture volcano). The compositions are compatible with either a Campanian or a Roman provenance. The cores, located on the Central Adriatic inner and outer shelf, recorded tephra referred to explosive events described in the literature: AP3 (sub-Plinian activity of the Somma-Vesuvius, 2710 ± 60 14C years BP); Avellino eruption (Somma-Vesuvius, 3548 ± 129 14C years BP); Agnano Monte Spina (Phlegrean Fields, 4100 ± 400 years BP); Mercato eruption (Somma-Vesuvius, 8010 ± 35 14C years BP; Agnano Pomici Principali eruption (Phlegrean Fields, 10,320 ± 50 14C years BP); Neapolitan Yellow Tuff (Phlegrean Fields, 12,100 ± 170 14C years BP). Some of these layers were also observed in the South Adriatic core IN68-9 in addition to younger ( AP2, sub-Plinian eruption, Somma-Vesuvius, 3225 ± 140 14C years BP), and older layers ( Pomici di Base eruption, Somma-Vesuvius, 18,300 ± 150 14C years BP). Significant is the tephra record of core RF95-7 that, for the first time in the Adriatic Sea, reports the occurrence of tephra layers older than 60 ka: the well known Mediterranean tephra layers X2 (ca. 70 ka), W1 (ca. 140 ka) and V2 (Roman origin, ca. 170 ka) as well as other tephra layers attributed, on the basis of geochemistry and biostratigraphy, to explosive eruptions occurred at Vico (138 ± 2 and 151 ± 3 ka BP) and Ischia (147-140 ka BP). Previous tephra correlations performed on other cores in the Central Adriatic Sea were also critically revised according to new available data, and integrated with the results of this study for a correlation at a regional scale. The most important key

  7. Results from Three Years of Ka-Band Propagation Characterization at Svalbard, Norway

    NASA Technical Reports Server (NTRS)

    Nessel, James; Zemba, Michael; Morse, Jacquelynne

    2015-01-01

    Over the next several years, NASA plans to launch several earth science missions which are expected to achieve data throughputs of 5-40 terabits per day transmitted from low earth orbiting spacecraft to ground stations. The current S-band and X-band frequency allocations in use by NASA, however, are incapable of supporting the data rates required to meet this demand. As such, NASA is in the planning stages to upgrade its existing Near Earth Network (NEN) polar ground stations to support Ka-band (25.5-27 GHz) operations. Consequently, it installed and operated a Ka-band radiometer at the Svalbard site. Svalbard was chosen as the appropriate site for two primary reasons: (1) Svalbard will be the first site to be upgraded to Ka-band operations within the NEN Polar Network enhancement plan, and (2) there exists a complete lack of Ka-band propagation data at this site (as opposed to the Fairbanks, AK NEN site, which has 5 years of characterization collected during the Advanced Communications Technology becomes imperative that characterization of propagation effects at these NEN sites is conducted to determine expected system Satellite (ACTS) campaign). processing and provide the Herein, we discuss the data three-year measurement results performance, particularly at low elevation angles ((is) less than 10 deg) from the ongoing Ka-band propagation characterization where spacecraft signal acquisition typically occurs. Since May 2011, NASA Glenn Research Center has installed and operated a Ka-band radiometer at the NEN site located in Svalbard, Norway. The Ka-band radiometer monitors the water vapor line, as well as 4 frequencies around 26.5 GHz at a fixed 10 deg elevation angle. Three-year data collection results indicate good campaign at Svalbard, Norway. Comparison of these results with the ITU models and existing ERA profile data indicates very good agreement when the 2010 rain maps and cloud statistics are used. Finally, the Svalbard data is used to derive the expected

  8. Results from Three Years of Ka-band Propagation Characterization at Svalbard, Norway

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Zemba, Michael; Morse, Jacquelynne

    2015-01-01

    Over the next several years, NASA plans to launch several earth science missions which are expected to achieve data throughputs of 5-40 terabits per day transmitted from low earth orbiting spacecraft to ground stations. The current S-band and X-band frequency allocations in use by NASA, however, are incapable of supporting the data rates required to meet this demand. As such, NASA is in the planning stages to upgrade its existing Near Earth Network (NEN) polar ground stations to support Ka-band (25.5-27 GHz) operations. Consequently, it installed and operated a Ka-band radiometer at the Svalbard site. Svalbard was chosen as the appropriate site for two primary reasons: (1) Svalbard will be the first site to be upgraded to Ka-band operations within the NEN Polar Network enhancement plan, and (2) there exists a complete lack of Ka-band propagation data at this site (as opposed to the Fairbanks, AK NEN site, which has 5 years of characterization collected during the Advanced Communications Technology becomes imperative that characterization of propagation effects at these NEN sites is conducted to determine expected system Satellite (ACTS) campaign). processing and provide the Herein, we discuss the data three-year measurement results performance, particularly at low elevation angles ((is) less than 10 deg) from the ongoing Ka-band propagation characterization where spacecraft signal acquisition typically occurs. Since May 2011, NASA Glenn Research Center has installed and operated a Ka-band radiometer at the NEN site located in Svalbard, Norway. The Ka-band radiometer monitors the water vapor line, as well as 4 frequencies around 26.5 GHz at a fixed 10 deg elevation angle. Three-year data collection results indicate good campaign at Svalbard, Norway. Comparison of these results with the ITU models and existing ERA profile data indicates very good agreement when the 2010 rain maps and cloud statistics are used. Finally, the Svalbard data is used to derive the expected

  9. SARAL/AltiKa observations for the studies of ice cover on lakes and oceans

    NASA Astrophysics Data System (ADS)

    Kouraev, Alexei; Zakharova, Elena; Remy, Frederique; Fleury, Sara; Guerreiro, Kevin; Willmes, Sascha; Suknev, Andrei

    2015-04-01

    With the launch of SARAL/AltiKa satellite mission scientific community has now a new source of information to study ice cover on water bodies and oceans. AltiKa observations provide a continuity with the previous satellite radar altimetry observations from ERS-1, -2 and ENVISAT mission that have the same orbit. Moreover, with the new Ka-band altimeter it gives new insights into the ice cover structure and properties. We present studies of ice cover on lakes (Lake Baikal) and Arctic ocean (for leads and polynyas detection). For Lake Baikal we use the synergy of simultaneous active (radar altimeter) and passive (radiometer) observations from radar altimetric satellites - SARAL/Altika and also TOPEX/Poseidon, Jason-1, ENVISAT and Geosat Follow-On. We present ice discrimination methodology from different satellite missions and discuss specificity of AltiKa observations. We analyse temporal variability of altimetric waveform parameters over ice-covered and ice-free surface for AltiKa and complement this analysis by satellite imagery (MODIS, Landsat), as well as our dedicated field observations of ice cover properties along the AltiKa tracks in spring 2013 and 2014. For the Arctic ocean we investigate the performance of SARAL/AltiKa to detect the leads and the coastal polynyas as well as its ability to represent spatial and temporal dynamic of water openings. The method consists first in analysis of along-track radar waveforms with collocated high-resolution Landsat images in order to localise ice/water transitions. We discuss the potential of several techniques that could be used for leads and polynya studies and for freeboard estimation. This research has been done in the framework of the Russian-French cooperation GDRI "CAR-WET-SIB", CNES TOSCA AO, ANR "CLASSIQUE", IDEX Transversalité InHERA, CNRS-Russia "Franco-Siberian Center for Research and Education" and PICS BaLaLaICA, ESA Proposal C1P.13132, Russian FZP 1.5 and EU FP7 "MONARCH-A" projects.

  10. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique

    PubMed Central

    2015-01-01

    Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field. PMID:26418550

  11. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

    PubMed

    Pichardo, Samuel; Silva, Rafael R C; Rubel, Oleg; Curiel, Laura

    2015-01-01

    Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

  12. Propagation experiment of COMETS Ka/Q-band communication link for future satellite cellular system

    NASA Technical Reports Server (NTRS)

    Hase, Yoshihiro

    1995-01-01

    Mobile/Personal Satellite Communication Systems in L/S-bands are going into the operational phase. In the future, they will be operated in much higher frequency bands, for example in Ka-band, because the available bandwidth in L-band is limited. Systems with large on-board antennas in higher frequencies allow the same configuration as terrestrial cellular radio systems, since the on-board antennas will have many small spot beams. This may be true especially in a low earth orbit system such as Teledesic, which will use Ka-band. The most important parameter of Satellite Cellular may be cell size, that is, a diameter of the spot beam. A system designer needs the local correlation data in a cell and the size of the correlative area. On the other hand, the most significant difficulty of Ka and higher band systems is the countermeasure to rain attenuation. Many-cell systems can manage the limited power of on-board transponders by controlling output power of each beam depending on the rain attenuation of each cell. If the cell size is equal to the correlative area, the system can probably achieve the maximum performance. Propagation data of Ka and higher band obtained in the past shows a long term cumulative feature and link availability, but do not indicate the correlative area. The Japanese COMETS satellite, which will be launched in February 1997, has transponders in Ka and Q-band. The CRL is planning to measure the correlative area using 21 GHz and 44 GHz CW transmissions from the COMETS.

  13. Linear Accelerator (LINAC)

    MedlinePlus

    ... is the device most commonly used for external beam radiation treatments for patients with cancer. The linear ... shape of the patient's tumor and the customized beam is directed to the patient's tumor. The beam ...

  14. Isolated linear blaschkoid psoriasis.

    PubMed

    Nasimi, M; Abedini, R; Azizpour, A; Nikoo, A

    2016-10-01

    Linear psoriasis (LPs) is considered a rare clinical presentation of psoriasis, which is characterized by linear erythematous and scaly lesions along the lines of Blaschko. We report the case of a 20-year-old man who presented with asymptomatic linear and S-shaped erythematous, scaly plaques on right side of his trunk. The plaques were arranged along the lines of Blaschko with a sharp demarcation at the midline. Histological examination of a skin biopsy confirmed the diagnosis of psoriasis. Topical calcipotriol and betamethasone dipropionate ointments were prescribed for 2 months. A good clinical improvement was achieved, with reduction in lesion thickness and scaling. In patients with linear erythematous and scaly plaques along the lines of Blaschko, the diagnosis of LPs should be kept in mind, especially in patients with asymptomatic lesions of late onset. PMID:27663156

  15. Inertial Linear Actuators

    NASA Technical Reports Server (NTRS)

    Laughlin, Darren

    1995-01-01

    Inertial linear actuators developed to suppress residual accelerations of nominally stationary or steadily moving platforms. Function like long-stroke version of voice coil in conventional loudspeaker, with superimposed linear variable-differential transformer. Basic concept also applicable to suppression of vibrations of terrestrial platforms. For example, laboratory table equipped with such actuators plus suitable vibration sensors and control circuits made to vibrate much less in presence of seismic, vehicular, and other environmental vibrational disturbances.

  16. Linear Alopecia Areata.

    PubMed

    Shetty, Shricharith; Rao, Raghavendra; Kudva, R Ranjini; Subramanian, Kumudhini

    2016-01-01

    Alopecia areata (AA) over scalp is known to present in various shapes and extents of hair loss. Typically it presents as circumscribed patches of alopecia with underlying skin remaining normal. We describe a rare variant of AA presenting in linear band-like form. Only four cases of linear alopecia have been reported in medical literature till today, all four being diagnosed as lupus erythematosus profundus. PMID:27625568

  17. Linear Alopecia Areata

    PubMed Central

    Shetty, Shricharith; Rao, Raghavendra; Kudva, R Ranjini; Subramanian, Kumudhini

    2016-01-01

    Alopecia areata (AA) over scalp is known to present in various shapes and extents of hair loss. Typically it presents as circumscribed patches of alopecia with underlying skin remaining normal. We describe a rare variant of AA presenting in linear band-like form. Only four cases of linear alopecia have been reported in medical literature till today, all four being diagnosed as lupus erythematosus profundus.

  18. Linear Alopecia Areata

    PubMed Central

    Shetty, Shricharith; Rao, Raghavendra; Kudva, R Ranjini; Subramanian, Kumudhini

    2016-01-01

    Alopecia areata (AA) over scalp is known to present in various shapes and extents of hair loss. Typically it presents as circumscribed patches of alopecia with underlying skin remaining normal. We describe a rare variant of AA presenting in linear band-like form. Only four cases of linear alopecia have been reported in medical literature till today, all four being diagnosed as lupus erythematosus profundus. PMID:27625568

  19. Position sensor for linear synchronous motors employing halbach arrays

    SciTech Connect

    Post, Richard Freeman

    2014-12-23

    A position sensor suitable for use in linear synchronous motor (LSM) drive systems employing Halbach arrays to create their magnetic fields is described. The system has several advantages over previously employed ones, especially in its simplicity and its freedom from being affected by weather conditions, accumulated dirt, or electrical interference from the LSM system itself.

  20. i3Drive, a 3D interactive driving simulator.

    PubMed

    Ambroz, Miha; Prebil, Ivan

    2010-01-01

    i3Drive, a wheeled-vehicle simulator, can accurately simulate vehicles of various configurations with up to eight wheels in real time on a desktop PC. It presents the vehicle dynamics as an interactive animation in a virtual 3D environment. The application is fully GUI-controlled, giving users an easy overview of the simulation parameters and letting them adjust those parameters interactively. It models all relevant vehicle systems, including the mechanical models of the suspension, power train, and braking and steering systems. The simulation results generally correspond well with actual measurements, making the system useful for studying vehicle performance in various driving scenarios. i3Drive is thus a worthy complement to other, more complex tools for vehicle-dynamics simulation and analysis.

  1. Conservation of angular momentum in polyatomic photochemical reactions: H2CO(v,J,Ka,Kc)yields+HCO(N,Ka,Kc,J)

    NASA Astrophysics Data System (ADS)

    Waugh, Siobhan E.; Terentis, Andrew C.; Metha, Gregory F.; Kable, Scott H.

    1998-05-01

    The photodissociation dynamics of the reaction H2CO + hv yields H + HCO have been investigated just above the reaction threshold. Formaldehyde was excited into specific J, Ka, Kc rotational states of three vibrational levels in the A(1A2) state. Molecules in these states undergo internal conversion back to the X (1A1) ground state on which the radical fragments are formed. The ensuring distribution of rotational energy in the HCO fragment was measured as a function of the N, Ka, Kc and J equals N +/- S quantum numbers of the fragment, and also the initial v, J, Ka, Kc quantum numbers of the parent. In a previous publication we investigated the dynamics of this reaction at low available energy and concluded that when only the N and Ka quantum numbers of both formaldehyde and the formyl radical are considered, the distributions are modeled well by phase space theory (PST). This is consistent with statistical dynamics on a bound, barrier less surface. Within approximately equals 10 cm-1 of the energetic threshold, a centrifugal barrier affected the populations by inhibiting product states that require large orbital angular momentum. Resolution of Kc in the parent and product gave large deviations from the PST model, however little data were available to quantify this observation. In this work we have extended then umber of initially excited H2CO levels to explore this 'Kc effect' further. We find that in the HCO Kc state or the lower energy state. This preference is consistent over all N for any particular initial H2CO state but may very for different initial states. Over the seven initial states probed here, four favored Kc and the other three Kc. A correlation between this Kc preference and the initial state was observed: odd Kc formaldehyde states produce Kc preference in HCO and vice versa for initially even Kc states. A comparison with one previous observation of this effect is presented, however no concrete explanation can be offered at this stage.

  2. Simple analytic potentials for linear ion traps

    NASA Technical Reports Server (NTRS)

    Janik, G. R.; Prestage, J. D.; Maleki, L.

    1990-01-01

    A simple analytical model was developed for the electric and ponderomotive (trapping) potentials in linear ion traps. This model was used to calculate the required voltage drive to a mercury trap, and the result compares well with experiments. The model gives a detailed picture of the geometric shape of the trapping potential and allows an accurate calculation of the well depth. The simplicity of the model allowed an investigation of related, more exotic trap designs which may have advantages in light-collection efficiency.

  3. Functional characterization of linear delay Langevin equations

    NASA Astrophysics Data System (ADS)

    Budini, Adrián A.; Cáceres, Manuel O.

    2004-10-01

    We present an exact functional characterization of linear delay Langevin equations driven by any noise structure defined through its characteristic functional. This method relies on the possibility of finding an explicitly analytical expression for each realization of the delayed stochastic process in terms of those of the driving noise. General properties of the transient dissipative dynamics are analyzed. The corresponding interplay with a color Gaussian noise is presented. As a full application of our functional method we study a model for population growth with non-Gaussian fluctuations: the Gompertz model driven by multiplicative white shot noise.

  4. Simple analytic potentials for linear ion traps

    NASA Technical Reports Server (NTRS)

    Janik, G. R.; Prestage, J. D.; Maleki, L.

    1989-01-01

    A simple analytical model was developed for the electric and ponderomotive (trapping) potentials in linear ion traps. This model was used to calculate the required voltage drive to a mercury trap, and the result compares well with experiments. The model gives a detailed picture of the geometric shape of the trapping potenital and allows an accurate calculation of the well depth. The simplicity of the model allowed an investigation of related, more exotic trap designs which may have advantages in light-collection efficiency.

  5. A linear accelerator for simulated micrometeors.

    NASA Technical Reports Server (NTRS)

    Slattery, J. C.; Becker, D. G.; Hamermesh, B.; Roy, N. L.

    1973-01-01

    Review of the theory, design parameters, and construction details of a linear accelerator designed to impart meteoric velocities to charged microparticles in the 1- to 10-micron diameter range. The described linac is of the Sloan Lawrence type and, in a significant departure from conventional accelerator practice, is adapted to single particle operation by employing a square wave driving voltage with the frequency automatically adjusted from 12.5 to 125 kHz according to the variable velocity of each injected particle. Any output velocity up to about 30 km/sec can easily be selected, with a repetition rate of approximately two particles per minute.

  6. Accurate pKa calculation of the conjugate acids of alkanolamines, alkaloids and nucleotide bases by quantum chemical methods.

    PubMed

    Gangarapu, Satesh; Marcelis, Antonius T M; Zuilhof, Han

    2013-04-01

    The pKa of the conjugate acids of alkanolamines, neurotransmitters, alkaloid drugs and nucleotide bases are calculated with density functional methods (B3LYP, M08-HX and M11-L) and ab initio methods (SCS-MP2, G3). Implicit solvent effects are included with a conductor-like polarizable continuum model (CPCM) and universal solvation models (SMD, SM8). G3, SCS-MP2 and M11-L methods coupled with SMD and SM8 solvation models perform well for alkanolamines with mean unsigned errors below 0.20 pKa units, in all cases. Extending this method to the pKa calculation of 35 nitrogen-containing compounds spanning 12 pKa units showed an excellent correlation between experimental and computational pKa values of these 35 amines with the computationally low-cost SM8/M11-L density functional approach.

  7. Production of high transient heat and particle fluxes in a linear plasma device

    SciTech Connect

    De Temmerman, G.; Zielinski, J. J.; Meiden, H. van der; Melissen, W.; Rapp, J.

    2010-08-23

    We report on the generation of high transient heat and particle fluxes in a linear plasma device by pulsed operation of the plasma source. A capacitor bank is discharged into the source to transiently increase the discharge current up to 1.7 kA, allowing peak densities and temperature of 70x10{sup 20} m{sup -3} and 6 eV corresponding to a surface power density of about 400 MW m{sup -2}.

  8. Eolian depositional phases during the past 50 ka and inferred climate variability for the Pampean Sand Sea, western Pampas, Argentina

    NASA Astrophysics Data System (ADS)

    Tripaldi, Alfonsina; Forman, Steven L.

    2016-05-01

    The Pampean Sand Sea, which occurs from the Argentinian Pampas to the eastern Andean piedmont, hosts presently stabilized dune fields spanning the late Quaternary. This study integrates previous results and presents new geomorphic, stratigraphic, sedimentological, and chronologic data for nineteen >2 m-thick eolian successions for the San Luis paleo-dune field, western Pampas, to better constrain the depositional history. Six eolian depositional phases are identified spanning the past 50 ka, interposed with paleosols and/or bounded by erosive surfaces. Age control was from 61 OSL ages of small aliquots of quartz grains from eolian stratigraphic units. The inferred timing of eolian phases are at ca. 70 ± 10 yr, 190 ± 20 yr, 12 to 1 ka, 22 to 17 ka, 29 to 24 ka, and 40 to 32 ka. A maximum span for periods of pedogenesis at ca. 12 to 17 ka, 22 to 24 ka, and 29 to 32 ka was provided by bounding OSL ages, which broadly overlap with high stands of pluvial lakes and glacier advances in the central Andes. We infer that the added precipitation may reflect expansion of the Southern Hemisphere monsoon, associated with Northern Hemisphere Heinrich events, leading to episodes of significantly wetter conditions (>350 mm MAP) to at least 35° S. Most of the Holocene (12 ka to 0.8 ka) was characterized by sand sheet deposit under drier than present conditions (100-450 mm MAP), associated with Monte-type vegetation (shrub steppe). The latest two eolian depositional phases, occurred at ca. 190 and 70 yr ago, during the historic period with European settlement and are related to anthropogenic landscape disturbance, though the youngest phase was concomitant with 1930s drought. Wet conditions dominated since ca. AD 1970 with new lakes and rivers forming across this eolian terrain; an incongruous environmental response in reference to drier conditions for most of the Holocene.

  9. Drive: Theory and Construct Validation.

    PubMed

    Siegling, Alex B; Petrides, K V

    2016-01-01

    This article explicates the theory of drive and describes the development and validation of two measures. A representative set of drive facets was derived from an extensive corpus of human attributes (Study 1). Operationalised using an International Personality Item Pool version (the Drive:IPIP), a three-factor model was extracted from the facets in two samples and confirmed on a third sample (Study 2). The multi-item IPIP measure showed congruence with a short form, based on single-item ratings of the facets, and both demonstrated cross-informant reliability. Evidence also supported the measures' convergent, discriminant, concurrent, and incremental validity (Study 3). Based on very promising findings, the authors hope to initiate a stream of research in what is argued to be a rather neglected niche of individual differences and non-cognitive assessment. PMID:27409773

  10. Drive: Theory and Construct Validation

    PubMed Central

    Petrides, K. V.

    2016-01-01

    This article explicates the theory of drive and describes the development and validation of two measures. A representative set of drive facets was derived from an extensive corpus of human attributes (Study 1). Operationalised using an International Personality Item Pool version (the Drive:IPIP), a three-factor model was extracted from the facets in two samples and confirmed on a third sample (Study 2). The multi-item IPIP measure showed congruence with a short form, based on single-item ratings of the facets, and both demonstrated cross-informant reliability. Evidence also supported the measures’ convergent, discriminant, concurrent, and incremental validity (Study 3). Based on very promising findings, the authors hope to initiate a stream of research in what is argued to be a rather neglected niche of individual differences and non-cognitive assessment. PMID:27409773

  11. Drive: Theory and Construct Validation.

    PubMed

    Siegling, Alex B; Petrides, K V

    2016-01-01

    This article explicates the theory of drive and describes the development and validation of two measures. A representative set of drive facets was derived from an extensive corpus of human attributes (Study 1). Operationalised using an International Personality Item Pool version (the Drive:IPIP), a three-factor model was extracted from the facets in two samples and confirmed on a third sample (Study 2). The multi-item IPIP measure showed congruence with a short form, based on single-item ratings of the facets, and both demonstrated cross-informant reliability. Evidence also supported the measures' convergent, discriminant, concurrent, and incremental validity (Study 3). Based on very promising findings, the authors hope to initiate a stream of research in what is argued to be a rather neglected niche of individual differences and non-cognitive assessment.

  12. MULTIPLE DIFFERENTIAL ROTARY MECHANICAL DRIVE

    DOEpatents

    Smits, R.G.

    1964-01-28

    This patent relates to a mechanism suitable for such applications as driving two spaced-apart spools which carry a roll film strip under conditions where the film movement must be rapidly started, stopped, and reversed while maintaining a constant tension on the film. The basic drive is provided by a variable speed, reversible rnotor coupled to both spools through a first differential mechanism and driving both spools in the same direction. A second motor, providing a constant torque, is connected to the two spools through a second differential mechanism and is coupled to impart torque to one spool in a first direction anid to the other spool in the reverse direction thus applying a constant tension to the film passing over the two spools irrespective of the speed or direction of rotation thereof. (AEC)

  13. The Effect of Spatial Scale on Paleovegetation Data-Model Comparisons for 6 ka and 21 ka in the Western United States

    NASA Astrophysics Data System (ADS)

    Shafer, S. L.; Bartlein, P. J.; Thompson, R. S.; Strickland, L. E.

    2010-12-01

    Climate-model simulations of past climates are often evaluated using both paleovegetation proxy data (e.g., pollen) and model simulations of past vegetation. These data-model comparison efforts provide important information for evaluating paleoclimate model simulations, and also for refining interpretations of paleovegetation proxy data and improving our understanding of past climate-vegetation interactions. A common limitation of these data-model comparisons is that the spatial resolution of paleoclimate simulations is frequently coarser than the spatial scales represented by the vegetation proxy data. This difference in spatial resolution is particularly important in topographically complex regions, such as the western United States. We used climate data simulated by coupled atmosphere-ocean general circulation models for 6 ka and 21 ka from the Paleoclimate Modelling Intercomparison Project phase 2 (PMIP2) database to evaluate the effects of spatial scale on the agreement between simulated and observed paleovegetation data. The climate data were downscaled to spatial resolutions of 30-minutes and finer and used with BIOME4, an equilibrium biogeography model, to simulate equilibrium vegetation for the western United States. The simulated vegetation was compared with fossil pollen and macrofossil data for the same region from the BIOME6000 data set. The results indicate the sensitivity of different vegetation types to changes in the spatial resolution of the data-model comparison and demonstrate the importance of data aggregation and spatial scale in evaluating data-model agreement.

  14. Superconducting linear actuator

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce; Hockney, Richard

    1993-01-01

    Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

  15. Mineralogy and geochemistry of the older (> 40 ka) ignimbrites on the Campanian Plain, southern Italy

    NASA Astrophysics Data System (ADS)

    Belkin, H. E.; Rolandi, G.; Jackson, J. C.; Cannatelli, C.; Doherty, A. L.; Petrosino, P.; De Vivo, B.

    2016-09-01

    The Campanian Plain in southern Italy has been volcanically active for at least the last 300 ka. The Campanian Ignimbrite (CI) erupted at 39.3 ka, has a volume of ≥ 310 km3 and a great areal extent. However, significant, but scattered deposits of older ignimbrites underlie the CI and document a long history of volcanism. We examined the mineralogy and geochemistry of 11 older ignimbrite strata by optical petrography, electron microprobe, scanning electron microscope, X-ray diffraction, and various whole-rock geochemical techniques. We have analyzed strata at Durazzano (116.1 ka), Moschiano (184.7 ka), Seiano Valley (245.9 and 289.6 ka), and Taurano - Acqua Feconia (157.4, 183.8, 205.6, and 210.4 ka) that have been previously dated on unaltered sanidine. The older ignimbrites are highly altered with loss on ignition (LOI) that ranges from 17 to 8 wt%. Whole-rock compositions reflect variable element mobility during weathering; e.g., CaO is enriched and Na2O depleted relative to hydration. X-ray diffraction identified major chabazite, kaolinite, and illite alteration products in some samples. Rhabdophane-(Nd), usually intergrown with chabazite and Mn-carbonate, indicates that some LREE were also mobilized during weathering. The phenocryst mineralogy is typical for Campanian Plain (CP) magmas and consists of plagioclase (An88 Ab11 Or1 to An32 Ab63 Or5), potassium feldspar (Or40 Ab57 An3 to Or79 Ab18 An3), biotite (TiO2 = ~ 4-7 wt%, BaO = up to 2 wt%, F = up to 2 wt%), diopside (Ca47Mg47Fe6 to Ca48Mg29Fe23), and titaniferous magnetite. Relatively immobile trace elements Zr, Hf, Th, Ta, V, and Nb were used to investigate element abundance and ratio compared to the Campanian Ignimbrite and other CP magmas. Zr/Hf of the older ignimbrites is similar to that of the CI, but Ta is depleted relative to Th and V is enriched compared to CI. Th/Ta and Nb/V distributions for most of the older ignimbrites are similar to those in the Neapolitan Yellow Tuff with the exception of

  16. Delay-Throughput Performance the Deep-Space Ka-Band Link

    NASA Technical Reports Server (NTRS)

    Shambayati, Shervin

    2008-01-01

    In this paper, performance of a first-in, first-out (FIFO), selective retransmission scheme for the deep-space Ka-band link is presented and compared to the performance of a comparable X-band link. In this analysis, 16 months of water vapor radiometer (WVR) and advanced water vapor radiometer (AWVR) data from the three Deep Space Network (DSN) Communication Complexes (DSCC) were used to emulate weather effects on X-band and Ka-band links from Mars. Mars Reconnaissance Orbiter (MRO) X-band and Ka-band telecommunications parameters were used for spacecraft telecommunications capabilities. One pass per week per complex was selected from MRO's Deep Space Network (DSN) schedule from April 1, 2006 to August 31, 2007 for a total of 207 passes (69 passes per complex) for this analysis. For each pass both X-band and Ka-band links were designed using at most two data rates so that the expected pass capacity would be maximized subject to a minimum availability requirement (MAR). In conjunction with the WVR/AWVR data, elevation profiles of the selected passes and models for the performance of the antennas in the DSN were used to emulate the performance of both links. It was assumed that the retransmission of the data takes place not on the same pass as the original transmission but during subsequent passes. The data collected before a pass was assumed to be a fraction of the expected capacity of the pass as calculated through the link design process. Infinite spacecraft storage was assumed to obtain an upper bound on the spacecraft storage requirement. The independent parameters of this analysis were MAR and the ratio of data collected before a pass to the expected pass capacity. Since the selected passes did not occur at regular intervals, the delay in this analysis was measured in terms of number of passes. The throughput was measured in terms of number of bits received successfully on the ground. The results indicate that reasonable delay performance could be achieved with

  17. Delay-Throughput Performance of the Deep-Space Ka-band Link

    NASA Technical Reports Server (NTRS)

    Shambayati, Shervin

    2008-01-01

    In this paper, performance of a first-in, first-out (FIFO), selective retransmission scheme for the deep-space Ka-band link is presented and compared to the performance of a comparable X-band link. In this analysis, 16 months of water vapor radiometer (WVR) and advanced water vapor radiometer (AWVR) data from the three Deep Space Network (DSN) Communication Complexes (DSCC) were used to emulate weather effects on X-band and Ka-band links from Mars. Mars Reconnaissance Orbiter (MRO) X-band and Ka-band telecommunications parameters were used for spacecraft telecommunications capabilities. One pass per week per complex was selected from MRO's Deep Space Network (DSN) schedule from April 1, 2006 to August 31, 2007 for a total of 207 passes (69 passes per complex) for this analysis. For each pass both X-band and Ka-band links were designed using at most two data rates so that the expected pass capacity would be maximized subject to a minimum availability requirement (MAR). In conjunction with the WVR/AWVR data, elevation profiles of the selected passes and models for the performance of the antennas in the DSN were used to emulate the performance of both links. It was assumed that the retransmission of the data takes place not on the same pass as the original transmission but during subsequent passes. The data collected before a pass was assumed to be a fraction of the expected capacity of the pass as calculated through the link design process. Infinite spacecraft storage was assumed to obtain an upper bound on the spacecraft storage requirement. The independent parameters of this analysis were MAR and the ratio of data collected before a pass to the expected pass capacity. Since the selected passes did not occur at regular intervals, the delay in this analysis was measured in terms of number of passes. The throughput was measured in terms of number of bits received successfully on the ground. The results indicate that reasonable delay performance could be achieved with

  18. ACTS Ka-Band Earth Stations: Technology, Performance, and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.; Struharik, Steven J.; Diamond, John J.; Stewart, David

    2000-01-01

    The Advanced Communications Technology Satellite (ACTS) Project invested heavily in prototype Ka-band satellite ground terminals to conduct an experiments program with the ACTS satellite. The ACTS experiment's program proposed to validate Ka-band satellite and ground station technology. demonstrate future telecommunication services. demonstrate commercial viability and market acceptability of these new services, evaluate system networking and processing technology, and characterize Ka-band propagation effects, including development of techniques to mitigate signal fading. This paper will present a summary of the fixed ground terminals developed by the NASA Glenn Research Center and its industry partners, emphasizing the technology and performance of the terminals (Part 1) and the lessons learned throughout their six year operation including the inclined orbit phase of operations (Full Report). An overview of the Ka-band technology and components developed for the ACTS ground stations is presented. Next. the performance of the ground station technology and its evolution during the ACTS campaign are discussed to illustrate the technical tradeoffs made during the program and highlight technical advances by industry to support the ACTS experiments program and terminal operations. Finally. lessons learned during development and operation of the user terminals are discussed for consideration of commercial adoption into future Ka-band systems. The fixed ground stations used for experiments by government, academic, and commercial entities used reflector based offset-fed antenna systems ranging in size from 0.35m to 3.4m antenna diameter. Gateway earth stations included two systems, referred to as the NASA Ground Station (NGS) and the Link Evaluation Terminal (LET). The NGS provides tracking, telemetry, and control (TT&C) and Time Division Multiple Access (TDMA) network control functions. The LET supports technology verification and high data rate experiments. The ground

  19. Revalidation and rationale for high pKa values of unconjugated bilirubin

    PubMed Central

    Ostrow, J Donald; Mukerjee, Pasupati

    2007-01-01

    Background Our prior solvent partition analysis, published in 1992, yielded pKa values for unconjugated bilirubin of about 8.1 and 8.4, but these results have been challenged and studies by other methods have suggested pKa values below 5.0. Methods We repeated our published solvent partition studies, using 14C-unconjugated bilirubin highly purified by extraction of residual labeled impurities from CHCl3 into an aqueous buffer, pH 7.0. Partition ratios at six pH values from 5.0 to 9.0 were determined by radioassay and compared with our prior values obtained by diazo assay. Results At pH values ranging from 4.8 to 9.2, stable aqueous/chloroform 14C-partition ratios did not differ significantly from our published partition ratios based on diazo assay. Conclusion These results support the high pKa values of unconjugated bilirubin, above 8.0, derived from our earlier solvent partition study. In both studies, our measurements were based on the rapid analysis of clearly under-saturated solutions of highly-purified bilirubin over a wide pH range, using properly purified and preserved solvents. No previous direct estimate of the aqueous pKa values of unconjugated bilirubin meets all these preconditions. Three theoretical factors acting in combination, each related to the unique, extensive internal H-bonding of the -COOH groups, are proposed to support high pKa values of unconjugated bilirubin in water: a) donation of an H-bond from the -OH moiety of the -COOH group, which is broken on ionization; b) hindered solvation of the -COO- group after ionization; and c) restricted rotation of the -COO- and -COOH groups. Our findings and rationale rebut methodological and theoretical criticisms leveled against our prior work. High pKa values for unconjugated bilirubin dictate that: a) bilirubin diacid, which readily diffuses across membranes and can cause neurotoxicity, is the dominant unbound bilirubin species of unconjugated bilirubin in plasma at physiological pH; b) at the near

  20. Paleoceanographic and Paleoclimatologic Records of the Sea of Marmara during the Last 70 KA

    NASA Astrophysics Data System (ADS)

    Cagatay, M. N.

    2015-12-01

    The Sea of Marmara is located between the Mediterranean and the Black Sea to which it is connected with the İstanbul (Bosporus) and Çanakkale (Dardanelles) straits having sill depths of 35 and 65 m below the present sea level, respectively. It is presently characterized by a two-way flow system consisting of the upper Black Sea and lower Mediterranean waters separated with a permanent halocline at -25 m. A 28.88 m long RV Marion Dufresne core MD01-2430 from the western high provides a continuous stratigraphic record for the last ca 70 ka. This record shows only one lacustrine-marine transition at ~ 12.6 cal ka BP over this period, indicating that the Sea of Marmara was under lacustrine conditions disconnected from the Mediterranean Sea from the beginning of Marine Isotope Stage 4 (MIS-4) to the early MIS-1. Soon after the reconnection, the Marmara sapropel started depositing under dysoxic-suboxic conditions during 12.33-5.7 cal ka BP. The periods of high inorganic (carbonate) and organic carbon production and burial in the Sea of Marmara correlate very closely with the Greenland Intertadials (GI) recorded in the NGRIP oxygen isotope and Black Sea Ca data sets. The two partly overlapping Ca peaks in the Sea of Marmara record corresponding to ~12.6 cal ka BP and 14.5 cal ka BP represent the authigenic carbonate deposition that resulted from the mixing of lacustrine Marmara and saline Mediterranean waters during the latest marine reconnection and the Greenland Interstadial-1 (GI-1) high productivity period, respectively. Low δ18O (down to -9‰) and high δ13C (+2.4‰) values of bulk carbonate during the GIs strongly suggest high input of fresh waters from the Black Sea and high organic productivity in the lacustrine Marmara under warm and humid conditions. Low "carbonate-free" K concentrations during the GIs suggest low detrital input in the Marmara "Lake", which in turn indicates low erosion rates in the catchment with a high vegetation density. In contrast, the

  1. Rover Takes a Sunday Drive

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This animation, made with images from the Mars Exploration Rover Spirit hazard-identification camera, shows the rover's perspective of its first post-egress drive on Mars Sunday. Engineers drove Spirit approximately 3 meters (10 feet) toward its first rock target, a football-sized, mountain-shaped rock called Adirondack. The drive took approximately 30 minutes to complete, including time stopped to take images. Spirit first made a series of arcing turns totaling approximately 1 meter (3 feet). It then turned in place and made a series of short, straightforward movements totaling approximately 2 meters (6.5 feet).

  2. Driving and Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Owsley, Cynthia; McGwin, Gerald, Jr.

    2008-01-01

    This article reviews the research literature on driving and age-related macular degeneration, which is motivated by the link between driving and the quality of life of older adults and their increased collision rate. It addresses the risk of crashes, driving performance, driving difficulty, self-regulation, and interventions to enhance, safety,…

  3. 32 CFR 634.43 - Driving records.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Driving records. 634.43 Section 634.43 National... INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.43 Driving... suspension or revocation actions. Table 5-1 of Part 634 Suspension/Revocation of Driving Privileges...

  4. 32 CFR 634.43 - Driving records.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Driving records. 634.43 Section 634.43 National... INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.43 Driving... suspension or revocation actions. Table 5-1 of Part 634 Suspension/Revocation of Driving Privileges...

  5. 32 CFR 634.43 - Driving records.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Driving records. 634.43 Section 634.43 National... INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.43 Driving... suspension or revocation actions. Table 5-1 of Part 634 Suspension/Revocation of Driving Privileges...

  6. 32 CFR 634.43 - Driving records.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Driving records. 634.43 Section 634.43 National... INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.43 Driving... suspension or revocation actions. Table 5-1 of Part 634 Suspension/Revocation of Driving Privileges...

  7. 32 CFR 634.43 - Driving records.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Driving records. 634.43 Section 634.43 National... INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.43 Driving... suspension or revocation actions. Table 5-1 of Part 634 Suspension/Revocation of Driving Privileges...

  8. A double B1-mode 4-layer laminated piezoelectric linear motor.

    PubMed

    Li, Xiaotian; Chen, Zhijiang; Dong, Shuxiang

    2012-12-01

    We report a miniature piezoelectric ultrasonic linear motor that is made of four Pb(Zr,Ti)O(3) (PZT) piezoelectric ceramic layers for low-voltage work. The 4-layer piezoelectric laminate works in two orthogonal first-bending modes for producing elliptical oscillations, which are then used to drive a contacting slider into continuous linear motion. Experimental results show that the miniature linear motor (size: 4 × 4 × 12 mm, weight: 1.7 g) can generate a large driving force of 0.48 N and a linear motion speed of up to 160 mm/s, using a 40 V(pp)/mm voltage drive at its resonance frequency of 64.5 kHz. The maximum efficiency of the linear motor is 30%.

  9. A square-plate ultrasonic linear motor operating in two orthogonal first bending modes.

    PubMed

    Chen, Zhijiang; Li, Xiaotian; Chen, Jianguo; Dong, Shuxiang

    2013-01-01

    A novel square-plate piezoelectric ultrasonic linear motor operated in two orthogonal first bending vibration modes (B₁) is proposed. The piezoelectric vibrator of the linear motor is simply made of a single PZT ceramic plate (sizes: 15 x 15 x 2 mm) and poled in its thickness direction. The top surface electrode of the square ceramic plate was divided into four active areas along its two diagonal lines for exciting two orthogonal B₁ modes. The achieved driving force and speed from the linear motor are 1.8 N and 230 mm/s, respectively, under one pair orthogonal voltage drive of 150 V(p-p) at the resonance frequency of 92 kHz. The proposed linear motor has advantages over conventional ultrasonic linear motors, such as relatively larger driving force, very simple working mode and structure, and low fabrication cost.

  10. Unsafe driving behaviour and four wheel drive vehicles: observational study

    PubMed Central

    Walker, Lesley; Williams, Jonathan; Jamrozik, Konrad

    2006-01-01

    Objective To assess the level of compliance with the new law in the United Kingdom mandating penalties for using a hand held mobile phone while driving, to compare compliance with this law with the one on the use of seat belts, and to compare compliance with these laws between drivers of four wheel drive vehicles and drivers of normal cars. Design Observational study with two phases—one within the “grace” period, the other starting one week after penalties were imposed on drivers using such telephones. Setting Three busy sites in London. Participants Drivers of 38 182 normal cars and 2944 four wheel drive vehicles. Main outcome measures Proportions of drivers seen to be using hand held mobile phones and not using seat belts. Results Drivers of four wheel drive vehicles were more likely than drivers of other cars to be seen using hand held mobile phones (8.2% v 2.0%) and not complying with the law on seat belts (19.5% v 15.0%). Levels of non-compliance with both laws were slightly higher in the penalty phase of observation, and breaking one law was associated with increased likelihood of breaking the other. Conclusions The level of non-compliance with the law on the use of hand held mobile phones by drivers in London is high, as is non-compliance with the law on seat belts. Drivers of four wheel drive vehicles were four times more likely than drivers of other cars to be seen using hand held mobile phones and slightly more likely not to comply with the law on seat belts. PMID:16798755

  11. Designing linear systolic arrays

    SciTech Connect

    Kumar, V.K.P.; Tsai, Y.C. . Dept. of Electrical Engineering)

    1989-12-01

    The authors develop a simple mapping technique to design linear systolic arrays. The basic idea of the technique is to map the computations of a certain class of two-dimensional systolic arrays onto one-dimensional arrays. Using this technique, systolic algorithms are derived for problems such as matrix multiplication and transitive closure on linearly connected arrays of PEs with constant I/O bandwidth. Compared to known designs in the literature, the technique leads to modular systolic arrays with constant hardware in each PE, few control lines, lexicographic data input/output, and improved delay time. The unidirectional flow of control and data in this design assures implementation of the linear array in the known fault models of wafer scale integration.

  12. Linear encoding device

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B. (Inventor)

    1993-01-01

    A Linear Motion Encoding device for measuring the linear motion of a moving object is disclosed in which a light source is mounted on the moving object and a position sensitive detector such as an array photodetector is mounted on a nearby stationary object. The light source emits a light beam directed towards the array photodetector such that a light spot is created on the array. An analog-to-digital converter, connected to the array photodetector is used for reading the position of the spot on the array photodetector. A microprocessor and memory is connected to the analog-to-digital converter to hold and manipulate data provided by the analog-to-digital converter on the position of the spot and to compute the linear displacement of the moving object based upon the data from the analog-to-digital converter.

  13. Electronic 4-wheel drive control device

    NASA Technical Reports Server (NTRS)

    Hayato, S.; Takanori, S.; Shigeru, H.; Tatsunori, S.

    1984-01-01

    The internal rotation torque generated during operation of a 4-wheel drive vehicle is reduced using a control device whose clutch is attached to one part of the rear-wheel drive shaft. One torque sensor senses the drive torque associated with the rear wheel drive shaft. A second sensor senses the drive torque associated with the front wheel drive shaft. Revolution count sensors sense the revolutions of each drive shaft. By means of a microcomputer, the engagement of the clutch is changed to insure that the ratio of the torque sensors remains constant.

  14. Drive reconfiguration mechanism for tracked robotic vehicle

    DOEpatents

    Willis, W. David

    2000-01-01

    Drive reconfiguration apparatus for changing the configuration of a drive unit with respect to a vehicle body may comprise a guide system associated with the vehicle body and the drive unit which allows the drive unit to rotate about a center of rotation that is located at about a point where the drive unit contacts the surface being traversed. An actuator mounted to the vehicle body and connected to the drive unit rotates the drive unit about the center of rotation between a first position and a second position.

  15. Noise fluctuations and drive dependence of the skyrmion Hall effect in disordered systems

    NASA Astrophysics Data System (ADS)

    Reichhardt, C.; Olson Reichhardt, C. J.

    2016-09-01

    Using a particle-based simulation model, we show that quenched disorder creates a drive-dependent skyrmion Hall effect as measured by the change in the ratio R={V}\\perp /{V}| | of the skyrmion velocity perpendicular (V ⊥) and parallel ({V}| | ) to an external drive. R is zero at depinning and increases linearly with increasing drive, in agreement with recent experimental observations. At sufficiently high drives where the skyrmions enter a free flow regime, R saturates to the disorder-free limit. This behavior is robust for a wide range of disorder strengths and intrinsic Hall angle values, and occurs whenever plastic flow is present. For systems with small intrinsic Hall angles, we find that the Hall angle increases linearly with external drive, as also observed in experiment. In the weak pinning regime where the skyrmion lattice depins elastically, R is nonlinear and the net direction of the skyrmion lattice motion can rotate as a function of external drive. We show that the changes in the skyrmion Hall effect correlate with changes in the power spectrum of the skyrmion velocity noise fluctuations. The plastic flow regime is associated with 1/f noise, while in the regime in which R has saturated, the noise is white with a weak narrow band signal, and the noise power drops by several orders of magnitude. At low drives, the velocity noise in the perpendicular and parallel directions is of the same order of magnitude, while at intermediate drives the perpendicular noise fluctuations are much larger.

  16. Linearly Adjustable International Portfolios

    NASA Astrophysics Data System (ADS)

    Fonseca, R. J.; Kuhn, D.; Rustem, B.

    2010-09-01

    We present an approach to multi-stage international portfolio optimization based on the imposition of a linear structure on the recourse decisions. Multiperiod decision problems are traditionally formulated as stochastic programs. Scenario tree based solutions however can become intractable as the number of stages increases. By restricting the space of decision policies to linear rules, we obtain a conservative tractable approximation to the original problem. Local asset prices and foreign exchange rates are modelled separately, which allows for a direct measure of their impact on the final portfolio value.

  17. Micro-Miniature Split Stirling Linear Crycooler

    NASA Astrophysics Data System (ADS)

    Veprik, A.; Zehtzer, S.; Vilenchik, H.; Pundak, N.

    2010-04-01

    Novel tactics for rescue, surveillance, reconnaissance, force protection, perimeter security, navigation and targeting often involve the use of miniature infrared imagers, where the cooled imaging systems are known to be superior to their uncooled rivals in terms of working range, resolution and ability to distinguish/track fast moving objects in dynamic infrared scenes. The latest technological advances in industrial applications of high-temperature infrared detectors have spurred the development of linearly driven, long life, dynamically quiet and aurally undetectable micro-miniature split Stirling linear cryogenic coolers. Recent progress in designing highly efficient "moving magnet" resonant linear actuators and dedicated smart electronics have enabled further improvements to the cooler's size, weight, power consumption, cooldown time and ownership costs. The authors report on the development of a novel micro-miniature split Stirling linear cryogenic cooler, where, by means of increasing the driving frequency up to 90 Hz, it appeared possible to shorten the cold finger to 19 mm. The cooler was specifically designed to cool a new generation of 130 K infrared detectors for portable infrared imagers, where compactness, low steady-state power consumption, fast cool-down time, vibration export and aural stealth are of primary concern.

  18. Controlling the pKa of the bacteriorhodopsin Schiff base by use of artificial retinal analogues

    SciTech Connect

    Sheves, M.; Albeck, A.; Friedman, N.; Ottolenghi, M.

    1986-05-01

    Artificial bacteriorhodopsin pigments based on synthetic retinal analogues carrying an electron-withdrawing CF3 substituent group were prepared. The effects of CF3 on the spectra, photocycles, and Schiff base pKa values of the pigments were analyzed. A reduction of 5 units in the pKa of the Schiff base is observed when the CF3 substituent is located at the C-13 polyene position, in the vicinity of the protonated Schiff base nitrogen. The results lead to the unambiguous characterization of the (direct) titration of the Schiff base in bacteriorhodopsin and to the conclusion that the deprotonation rate of the Schiff base during the photocycle (i.e., the generation of the M412 intermediate) is determined by a structural change in the protein.

  19. pH indicator titration: a novel fast pKa determination method.

    PubMed

    Kong, Xiaole; Zhou, Tao; Liu, Zudong; Hider, Robert C

    2007-10-01

    This study describes a fast spectrophotometic titration method for apparent ionization constant (pKa) determination. In this method, a Universal pH indicator is utilized instead of the conventional pH electrode. An autoburette is set to add HCl at a constant rate to a vigorously stirred 1 cm UV cuvette which contains sample and indicator solution. A spectrophotometer continuously records the spectra. Acquired spectral data are processed by calculating the pH from the indicator spectra in the visible region and extracting sample spectra from the UV region. Five compounds possessing pKa values in the range 2-10 were investigated. These results differed from measurements by conventional spectrophotometric titration by +/-0.05 to +/-0.10 log unit.

  20. Electromagnetic properties of polyurethane template-based carbon foams in Ka-band

    NASA Astrophysics Data System (ADS)

    Bychanok, D.; Plyushch, A.; Piasotski, K.; Paddubskaya, A.; Voronovich, S.; Kuzhir, P.; Baturkin, S.; Klochkov, A.; Korovin, E.; Letellier, M.; Schaefer, S.; Szczurek, A.; Fierro, V.; Celzard, A.

    2015-09-01

    The electromagnetic (EM) properties of polyurethane template-based reticulated carbon foams were investigated in the 26-37 GHz microwave frequency range (Ka-band). It was experimentally proved that carbon foams of a thickness of 2 mm and a density of 22-55 mg cm-3 are almost not transparent to microwave radiation, and this is especially true for the densest ones. Depending on bulk density, the EM response of carbon foams in the microwave region can be mainly accounted for by either reflection or absorption. EM shielding efficiency of more dilute samples is due to absorption mechanisms, whereas denser foams provide up to 80% reflection of EM signals. EM properties of carbon foams in the Ka-band can be accurately predicted by a very simple model based on Fresnel formulae developed in this communication.