WorldWideScience

Sample records for arrays driving dynamic

  1. Redundant arrays of IDE drives

    Energy Technology Data Exchange (ETDEWEB)

    D.A. Sanders et al.

    2002-01-02

    The authors report tests of redundant arrays of IDE disk drives for use in offline high energy physics data analysis. Parts costs of total systems using commodity EIDE disks are now at the $4000 per Terabyte level. Disk storage prices have now decreased to the point where they equal the cost per Terabyte of Storage Technology tape silos. The disks, however, offer far better granularity; even small institutions can afford to deploy systems. The tests include reports on software RAID-5 systems running under Linux 2.4 using Promise Ultra 100{trademark} disk controllers. RAID-5 protects data in case of a single disk failure by providing parity bits. Tape backup is not required. Journaling file systems are used to allow rapid recovery from crashes. The data analysis strategy is to encapsulate data and CPU processing power. Analysis for a particular part of a data set takes place on the PC where the data resides. The network is only used to put results together. They explore three methods of moving data between sites; internet transfers, not pluggable IDE disks in FireWire cases, and DVD-R disks.

  2. Compact dynamic microfluidic iris array

    Science.gov (United States)

    Kimmle, Christina; Doering, Christoph; Steuer, Anna; Fouckhardt, Henning

    2011-09-01

    A dynamic microfluidic iris is realized. Light attenuation is achieved by absorption of an opaque liquid (e.g. black ink). The adjustment of the iris diameter is achieved by fluid displacement via a transparent elastomer (silicone) half-sphere. This silicone calotte is hydraulically pressed against a polymethylmethacrylate (PMMA) substrate as the bottom window, such that the opaque liquid is squeezed away, this way opening the iris. With this approach a dynamic range of more than 60 dB can be achieved with response times in the ms to s regime. The design allows the realization of a single iris as well as an iris array. So far the master for the molded silicone structure was fabricated by precision mechanics. The aperture diameter was changed continuously from 0 to 8 mm for a single iris and 0 to 4 mm in case of a 3 x 3 iris array. Moreover, an iris array was combined with a PMMA lens array into a compact module, the distance of both arrays equaling the focal length of the lenses. This way e.g. spatial frequency filter arrays can be realized. The possibility to extend the iris array concept to an array with many elements is demonstrated. Such arrays could be applied e.g. in light-field cameras.

  3. Solar array flight dynamic experiment

    Science.gov (United States)

    Schock, Richard W.

    1987-01-01

    The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures' dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-41D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

  4. Linear micromechanical stepping drive for pinhole array positioning

    International Nuclear Information System (INIS)

    Endrödy, Csaba; Mehner, Hannes; Hoffmann, Martin; Grewe, Adrian

    2015-01-01

    A compact linear micromechanical stepping drive for positioning a 7 × 5.5 mm 2 optical pinhole array is presented. The system features a step size of 13.2 µm and a full displacement range of 200 µm. The electrostatic inch-worm stepping mechanism shows a compact design capable of positioning a payload 50% of its own weight. The stepping drive movement, step sizes and position accuracy are characterized. The actuated pinhole array is integrated in a confocal chromatic hyperspectral imaging system, where coverage of the object plane, and therefore the useful picture data, can be multiplied by 14 in contrast to a non-actuated array. (paper)

  5. Dynamic array of dark optical traps

    DEFF Research Database (Denmark)

    Daria, V.R.; Rodrigo, P.J.; Glückstad, J.

    2004-01-01

    A dynamic array of dark optical traps is generated for simultaneous trapping and arbitrary manipulation of multiple low-index microstructures. The dynamic intensity patterns forming the dark optical trap arrays are generated using a nearly loss-less phase-to-intensity conversion of a phase-encode...

  6. Effects of driving time on microsaccadic dynamics.

    Science.gov (United States)

    Di Stasi, Leandro L; McCamy, Michael B; Pannasch, Sebastian; Renner, Rebekka; Catena, Andrés; Cañas, José J; Velichkovsky, Boris M; Martinez-Conde, Susana

    2015-02-01

    Driver fatigue is a common cause of car accidents. Thus, the objective detection of driver fatigue is a first step toward the effective management of fatigue-related traffic accidents. Here, we investigated the effects of driving time, a common inducer of driver fatigue, on the dynamics of fixational eye movements. Participants drove for 2 h in a virtual driving environment while we recorded their eye movements. Microsaccade velocities decreased with driving time, suggesting a potential effect of fatigue on microsaccades during driving.

  7. Predictions of fast wave heating, current drive, and current drive antenna arrays for advanced tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Batchelor, D.B.; Baity, F.W.; Carter, M.D. [and others

    1994-12-31

    The objective of the advanced tokamak program is to optimize plasma performance leading to a compact tokamak reactor through active, steady state control of the current profile using non-inductive current drive and profile control. To achieve these objectives requires compatibility and flexibility in the use of available heating and current drive systems--ion cyclotron radio frequency (ICRF), neutral beams, and lower hybrid. For any advanced tokamak, the following are important challenges to effective use of fast waves in various roles of direct electron heating, minority ion heating, and current drive: (1) to employ the heating and current drive systems to give self-consistent pressure and current profiles leading to the desired advanced tokamak operating modes; (2) to minimize absorption of the fast waves by parasitic resonances, which limit current drive; (3) to optimize and control the spectrum of fast waves launched by the antenna array for the required mix of simultaneous heating and current drive. The authors have addressed these issues using theoretical and computational tools developed at a number of institutions by benchmarking the computations against available experimental data and applying them to the specific case of TPX.

  8. Predictions of fast wave heating, current drive, and current drive antenna arrays for advanced tokamaks

    International Nuclear Information System (INIS)

    Batchelor, D.B.; Baity, F.W.; Carter, M.D.

    1994-01-01

    The objective of the advanced tokamak program is to optimize plasma performance leading to a compact tokamak reactor through active, steady state control of the current profile using non-inductive current drive and profile control. To achieve these objectives requires compatibility and flexibility in the use of available heating and current drive systems--ion cyclotron radio frequency (ICRF), neutral beams, and lower hybrid. For any advanced tokamak, the following are important challenges to effective use of fast waves in various roles of direct electron heating, minority ion heating, and current drive: (1) to employ the heating and current drive systems to give self-consistent pressure and current profiles leading to the desired advanced tokamak operating modes; (2) to minimize absorption of the fast waves by parasitic resonances, which limit current drive; (3) to optimize and control the spectrum of fast waves launched by the antenna array for the required mix of simultaneous heating and current drive. The authors have addressed these issues using theoretical and computational tools developed at a number of institutions by benchmarking the computations against available experimental data and applying them to the specific case of TPX

  9. Dynamical Properties of Two-Dimensional Josephson Junction Arrays

    Science.gov (United States)

    1990-05-01

    current, i,0 , simply by Ic. = Mico , where M = 1000 is the number of junctions in parallel across the width of the array perpendicular to the current...identical junctions or some other form of disorder, the motion may be more complex , including effects such as vortex lattice shear. At higher temperatures...with the rf drive current as proposed in the vortex motion model. We have found interesting and complex dynamical behavior in the simulations that

  10. Dynamics and control of instrumented harmonic drives

    Science.gov (United States)

    Kazerooni, H.; Ellis, S. R. (Principal Investigator)

    1995-01-01

    Since torque in harmonic drives is transmitted by a pure couple, harmonic drives do not generate radial forces and therefore can be instrumented with torque sensors without interference from radial forces. The installation of torque sensors on the stationary component of harmonic drives (the Flexipline cup in this research work) produce backdrivability needed for robotic and telerobotic compliant maneuvers. Backdrivability of a harmonic drive, when used as torque increaser, means that the output shaft can be rotated via finite amount of torque. A high ratio harmonic drive is non-backdrivable because its output shaft cannot be turned by applying a torque on it. This article first develops the dynamic behavior of a harmonic drive, in particular the non-backdrivability, in terms of a sensitivity transfer function. The instrumentation of the harmonic drive with torque sensor is then described. This leads to a description of the control architecture which allows modulation of the sensitivity transfer function within the limits established by the closed-loop stability. A set of experiments on an active hand controller, powered by a DC motor coupled to an instrumented harmonic drive, is given to exhibit this method's limitations.

  11. Driving market dynamics with technology

    International Nuclear Information System (INIS)

    Sollecito, L.

    2002-01-01

    As a result of changes in the role of hardware, software and communications in the management of all types of services, including electrical utilities, companies are more and more forced to rethink their approach to every aspect of doing business and to pay more attention to integrated, enterprise-wide approaches. In the electric industry, deregulation and the need to operate more competitively, have been primarily responsible for forcing the issue of the integration. As customer demand becomes increasingly more complex, and the growth in power generation is putting more and more strain on the aging existing infrastructure, many utilities are looking to move distributed generation closer to the load. While distributed generation promises to deliver a number of compelling advantages to end users, it will also place significant onus on the utilities to find more efficient ways to monitor and control usages. Utilities will be forced to examine ways to track and match loads for protection and generation over multiple devices, extract information in various forms and access timely information to ensure overall stability. Forced to re-think their approach, utility companies increasingly come to realize that the way to win this battle is through technology. Relay and communications technology in particular, are significantly changing the utility landscape, revolutionizing the way utilities and industry can manage their transmission, generation and protection needs. The move from leased phone lines to an array of microwave and fiber optic communications that allow for the delivery of data over the Ethernet or any other protocol at unprecedented speed, is just one example of the changes that are taking place. At the same time, wireless connectivity and Internet-based monitoring and control are making strong advances toward becoming increasingly prevalent factors in substation automation. Web-enabled services that are designed to deliver monitoring and administrative

  12. Kinematics and Dynamics of Roller Chain Drives

    DEFF Research Database (Denmark)

    Fuglede, Niels

    There are two main subjects of this work: Kinematic and dynamic modeling and analysis of roller chain drives. In the kinematic analysis we contribute first with a complete treatment of the roller chain drive modeled as a four-bar mechanism. This includes a general, exact and approximate analysis...... which is useful for predicting the characteristic loading of the roller chain drive. As a completely novel contribution, a kinematic model and analysis is presented which includes both spans and sprockets in a simple chain drive system. A general procedure for determination of the total wrapping length...... is presented, which also allows for exact sprocket center positions for a chain with a given number of links. Results show that the total chain wrapping length varies periodically with the tooth frequency. These results are of practical importance to both the design, installation and operation of roller chain...

  13. Classical-driving-assisted entanglement dynamics control

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying-Jie, E-mail: yingjiezhang@qfnu.edu.cn [Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165 (China); Han, Wei [Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165 (China); Xia, Yun-Jie, E-mail: yjxia@qfnu.edu.cn [Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165 (China); Fan, Heng, E-mail: hfan@iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Collaborative Innovation Center of Quantum Matter, Beijing, 100190 (China)

    2017-04-15

    We propose a scheme of controlling entanglement dynamics of a quantum system by applying the external classical driving field for two atoms separately located in a single-mode photon cavity. It is shown that, with a judicious choice of the classical-driving strength and the atom–photon detuning, the effective atom–photon interaction Hamiltonian can be switched from Jaynes–Cummings model to anti-Jaynes–Cummings model. By tuning the controllable atom–photon interaction induced by the classical field, we illustrate that the evolution trajectory of the Bell-like entanglement states can be manipulated from entanglement-sudden-death to no-entanglement-sudden-death, from no-entanglement-invariant to entanglement-invariant. Furthermore, the robustness of the initial Bell-like entanglement can be improved by the classical driving field in the leaky cavities. This classical-driving-assisted architecture can be easily extensible to multi-atom quantum system for scalability.

  14. Vortex dynamics in Josephson junctions arrays

    International Nuclear Information System (INIS)

    Shalom, Diego Edgar

    2005-01-01

    In this work we study the dynamics of vortices in two-dimensional overdamped Josephson Junctions Arrays (JJA) driven by dc current in a wide range of conditions varying magnetic field and temperature using experiments, numerical simulations and analytic studies.We develop the Fixed Phase method, a variation of numeric relaxation techniques in which we fix and control the phase of some islands, adjacent to the vortex center, while allowing all other phases in the system to relax.In this way we are able to pull and push the vortex uphill, as we are forcing the center of rotation of the vortex currents to be in a defined location, allowing us to calculate the potential energy of a vortex located in any arbitrary position.We use this method to study the potential energy of a vortex in a variety of situations in homogeneous and non-homogeneous JJA, such as arrays with defects, channel arrays and ratchets.We study the finite size effects in JJA by means of analytic and numerical tools.We implement the rings model, in which we replace the two-dimensional square array by a series of square, concentric, uncoupled rings. This is equivalent to disregarding the radial junctions that couple consecutive rings.In spite of its extreme simplicity, this model holds the main ingredients of the magnetic dependence of the energy.We combine this model with other terms that take into account the dependence in the position of the vortex to obtain a general expression for the potential energy of a vortex in a finite JJA with applied magnetic field.We also present an expression for the first critical field, corresponding to the value of the magnetic field in which the entrance of the first vortex becomes energetically favorable.We build and study JJA modulated to form periodic and asymmetrical potentials for the vortices, named ratchet potentials.The experimental results clearly show the existence of a rectification in the motion of vortices in these potentials.Under certain conditions we

  15. Statics and dynamics of colloidal particles on optical tray arrays

    Energy Technology Data Exchange (ETDEWEB)

    Reichardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory

    2009-01-01

    We examine the statics and dynamics of charged colloids interacting with periodic optical trap arrays. In particular we study the regime where more than one colloid is confined in each trap, creating effective dimer, trimer, and higher order states called colloidal molecular crystals. The n-mer states have all effective orientational degree of freedom which can be controlled with an external driving field. In general, the external field causes a polarization effect where the orientation of the n-mers aligns with the external field, similar to liquid crystal systems. Additionally, under a rotating external drive the n-mers can rotate with the drive. In some cases a series of structural transitions in the colloidal crystal states occur in the rotating field due to a competition between the ordering of the colloidal molecular crystals and the polarization effect which orients the n-mers in the direction of the drive. We also show that for some parameters, the n-mers continuously rotate with the drive without witching, that depinning transitions can occur where the colloids jump from well to well, and that there are a number of distinct dynamical transitions between the phases. Finally, we illustrate colloidal orderings at fillings of more than four colloids per trap, indicating that it is possible to create higher order colloidal crystal cluster phases.

  16. Chain Drive Simulation Using Spatial Multibody Dynamics

    Directory of Open Access Journals (Sweden)

    Mohamed A. Omar

    2014-04-01

    Full Text Available This paper presents an efficient approach for modeling chain derives using multibody dynamics formulation based on the spatial algebra. The recursive nonlinear dynamic equations of motion are formulated using spatial Cartesian coordinates and joint variables to form an augmented set of differential-algebraic equations. The spatial algebra is used to express the kinematic and dynamic equations leading to consistent and compact set of equations. The connectivity graph is used to derive the system connectivity matrix based on the system topological relations. The connectivity matrix is used to eliminate the Cartesian quantities and to project the forces and inertia into the joint subspace. This approach will result in a minimum set of equation and can avoid iteratively solving the system of differential and algebraic equations to satisfy the constraint equations. In order to accurately capture the full dynamics of the chain links, each link in the chain is modeled as rigid body with full 6 degrees of freedom. To avoid singularities in closed loop configurations, the chain drive is considered a kinematically decoupled subsystem and the interaction between the links and other system components is modeled using force elements. The out-of-plane misalignment between the sprockets can be easily modeled using a compliant force element to model the joints between each two adjacent links. The nonlinear three dimensional contact forces between the chain links and the sprockets are modeled using elastic spring-damper element and accounts for the sliding friction. The proposed approach can be used to model complex drive chain, bicycle chain as well as conveyance systems. Results show that realistic behavior of the chain as well as out-of-plane vibration can be easily captured using the presented approach. The proposed approach for chain drive subsystem could be easily appended to any other multibody simulation system.

  17. Analytical Kinematics and Coupled Vibrations Analysis of Mechanical System Operated by Solar Array Drive Assembly

    Science.gov (United States)

    Sattar, M.; Wei, C.; Jalali, A.; Sattar, R.

    2017-07-01

    To address the impact of solar array (SA) anomalies and vibrations on performance of precision space-based operations, it is important to complete its accurate jitter analysis. This work provides mathematical modelling scheme to approximate kinematics and coupled micro disturbance dynamics of rigid load supported and operated by solar array drive assembly (SADA). SADA employed in analysis provides a step wave excitation torque to activate the system. Analytical investigations into kinematics is accomplished by using generalized linear and Euler angle coordinates, applying multi-body dynamics concepts and transformations principles. Theoretical model is extended, to develop equations of motion (EoM), through energy method (Lagrange equation). The main emphasis is to research coupled frequency response by determining energies dissipated and observing dynamic behaviour of internal vibratory systems of SADA. The disturbance model captures discrete active harmonics of SADA, natural modes and vibration amplifications caused by interactions between active harmonics and structural modes of mechanical assembly. The proposed methodology can help to predict true micro disturbance nature of SADA operating rigid load. Moreover, performance outputs may be compared against actual mission requirements to assess precise spacecraft controller design to meet next space generation stringent accuracy goals.

  18. Plate tectonics drive tropical reef biodiversity dynamics

    Science.gov (United States)

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F.; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J.; de Santana, Charles N.; Heine, Christian; Mouillot, David; Bellwood, David R.; Pellissier, Loïc

    2016-05-01

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics.

  19. Dynamics and control of electrical drives

    Energy Technology Data Exchange (ETDEWEB)

    Wach, Piotr [Politechnika Opolska, Opole (Poland). Inst. of Electromechanical Systems and Applied Informatics

    2011-07-01

    Dynamics is a science concerned with movement and changes. In the most general approach it relates to life processes as well as behavior in nature in rest. It governs small particles, technical objects, conversion of matter and materials but also concerns people, groups of people in their individual and, in particular, social dimension. In dynamics we always have to do with causes or stimuli for motion, the rules of reaction or behavior and its result in the form of trajectory of changes. This book is devoted to dynamics of a wide class of specific but very important objects such as electromechanical systems. This is a very rigorous discipline and has a long tradition, as its theoretical bases were formulated in the first half of the XIX century by d' Alembert, Lagrange, Hamilton, Maxwell and other prominent scientists, but their crucial results were based on previous pioneering research of others such as Copernicus, Galileo, Newton..This book in its theoretical foundations is based on the principle of least action which governs classical as well as relativistic mechanics and electromagnetism and leads to Lagrange's equations which are applied in the book as universal method to construct equations of motion of electromechanical systems. It gives common and coherent grounds to formulate mathematical models for all lumped parameters' electromechanical systems, which are vital in our contemporary industry and civilized everyday life. From these remarks it seems that the book is general and theoretical but in fact it is a very practical one concerning modern electrical drives in a broad sense, including electromechanical energy conversion, induction motor drives, brushless DC drives with a permanent magnet excitation and switched reluctance machines (SRM). And of course their control, which means shaping of their trajectories of motion using modern tools, their designed autonomy in keeping a track according to our programmed expectations. The problems

  20. PV Array Driven Adjustable Speed Drive for a Lunar Base Heat Pump

    Science.gov (United States)

    Domijan, Alexander, Jr.; Buchh, Tariq Aslam

    1995-01-01

    A study of various aspects of Adjustable Speed Drives (ASD) is presented. A summary of the relative merits of different ASD systems presently in vogue is discussed. The advantages of using microcomputer based ASDs is now widely understood and accepted. Of the three most popular drive systems, namely the Induction Motor Drive, Switched Reluctance Motor Drive and Brushless DC Motor Drive, any one may be chosen. The choice would depend on the nature of the application and its requirements. The suitability of the above mentioned drive systems for a photovoltaic array driven ASD for an aerospace application are discussed. The discussion is based on the experience of the authors, various researchers and industry. In chapter 2 a PV array power supply scheme has been proposed, this scheme will have an enhanced reliability in addition to the other known advantages of the case where a stand alone PV array is feeding the heat pump. In chapter 3 the results of computer simulation of PV array driven induction motor drive system have been included. A discussion on these preliminary simulation results have also been included in this chapter. Chapter 4 includes a brief discussion on various control techniques for three phase induction motors. A discussion on different power devices and their various performance characteristics is given in Chapter 5.

  1. Design of a Solar Motor Drive System Fed by a Direct-Connected Photovoltaic Array

    Directory of Open Access Journals (Sweden)

    AYDOGMUS, O.

    2012-08-01

    Full Text Available A solar motor pump drive system is modeled and simulated. The proposed drive system does not require any kind of energy storage system and dc-dc converter. The system is connected directly to a photovoltaic (PV array. Thus, a low cost solar system can be achieved. A vector controlled Permanent Magnet Synchronous Motor (PMSM is used as a solar motor to increase the efficiency of system. The motor is designed for a low rated voltage level about 24V. The hill climbing MPPT method is used for balanced the motor power and PV power to obtain a high efficiency. The results are performed by using MATLAB/SimPowerSystem blocks. In addition, the PV array is modeled to allow for the possibility of running as on-line adjustable in simulation environment without using lookup table. The performances of motor, MPPT and drive system are analyzed in different conditions as temperature and irradiation of PV array.

  2. Controlling the flux dynamics in superconductors by nanostructured magnetic arrays

    Science.gov (United States)

    Kapra, Andrey

    In this thesis we investigate theoretically how the critical current jc of nano-engineered mesoscopic superconducting film can be improved and how one can control the dynamics of the magnetic flux, e.g., the transition from flux-pinned to flux-flow regime, using arrays of magnetic nanostructures. In particularly we investigate: (1) Vortex transport phenomena in superconductors with deposited ferromagnetic structures on top, and the influence of the sample geometry on the critical parameters and on the vortex configurations. Changing geometry of the magnetic bars and magnetization of the bars will affect the critical current jc of the superconducting film. Such nanostructured ferromagnets strongly alter the vortex structure in its neighborhood. The influence of geometry, position and magnetization of the ferromagnet (single bar or regular lattice of the bars) on the critical parameters of the superconductor is investigated. (2) Effect of flux confinement in narrow superconducting channels with zigzag-shaped banks: the flux motion is confined in the transverse (perpendicular) direction of a diamond-cell-shape channel. The matching effect for the magnetic flux is found in the system relevantless of boundary condition. We discuss the dynamics of vortices in the samples and vortex pattern formation in the channel. We show how the inclusion of higher-Tc superconductor into the sample can lead to enhanced properties of the system. By adding an external driving force, we study the vortex dynamics. The different dynamic regimes are discussed. They allowed an effective control of magnetic flux in superconductors.

  3. Single and nested tungsten-wire-array dynamics and applications to inertial confinement fusion

    Science.gov (United States)

    Cuneo, Michael

    2005-10-01

    Wire array z-pinches show great promise as x-ray sources for indirect-drive inertial confinement fusion (ICF). The double z-pinch hohlraum, for example, has produced capsule radiation drive symmetric to within 3%. This ICF concept will require that each of two 20-mm-diam arrays scale to x-ray powers ˜1 PW, to drive high-yield (>0.2 GJ) capsules to ignition. High-yield fusion will also require a temporally shaped radiation pulse to drive a low-entropy capsule implosion. Recently, improved understanding of high current (11-19 MA) single and nested wire-array dynamics has enabled significant progress towards these goals. As at lower currents, a single wire array (and both the outer and inner arrays of a nested system) shows a wire ablation phase, axial modulation of the ablation rate, a larger ablation rate for larger diameter wires, trailing mass and trailing current. These processes and others produce a broad mass profile that may impact the optimization of x-ray output for single and nested arrays. Our new insights into wire array physics have led to 20-mm-diam single and nested arrays with peak powers of 150-190 TW at implosion times of 55-90 ns, increased from 60-120 TW at 95-110 ns, improving power scaling. Radiation pulse shapes required for 3-shock isentropic compression of high-yield ICF capsules have also been demonstrated with nested wire arrays operating in current-transfer mode. In collaboration with: D.B. Sinars, R.A. Vesey, E.M. Waisman, W.A. Stygar, D.E. Bliss, S.V. Lebedev, J.P. Chittenden, P.V. Sasorov, R.W. Lemke, E.P. Yu, B.B. Afeyan, G.R. Bennett, M.G. Mazarakis, M.R. Lopez, M.E. Savage, J.L. Porter, T.A. Mehlhorn.

  4. Worst-case-efficient dynamic arrays in practice

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2016-01-01

    The basic operations of a dynamic array are operator[], push back, and pop back. This study is an examination of variations of dynamic arrays that support these operations at O(1) worst-case cost. In the literature, many solutions have been proposed, but little information is available on their m...

  5. Roller-chain Drives Mechanics using Multibody Dynamics Tools

    DEFF Research Database (Denmark)

    Ambrosio, Jorge A. C.; Hansen, John Michael

    1999-01-01

    An integrated model for the simulation of roller-chain drives based on a multibody dynamics methodology is presented here in order to describeits complex dynamic behavior. The chain is modeled by masses lumped at the roller locations and connected by translational spring-damper elements in order...

  6. Dynamics Performance and Abrasive Wear of the Automotive Drive Shaft

    Directory of Open Access Journals (Sweden)

    Jian Mao

    2014-06-01

    Full Text Available An automotive drive shaft is used in a front drive transmission vehicle for transmitting rotary movement from the gearbox output shaft to the wheels with a constant velocity. This paper presents the kinematic model of ball joint and tripod joint with consideration of clearance and proposes a simplified dynamics model of the drive shaft. The simulation of the dynamics model is given by the measured data. Also, the abrasive wear of the ball type joint is tested on the experimental setup with consideration of full loading. The results show that the dynamics of the motion will be affected by the clearance when the loading changes its direction. The motion will be stable due to the damping. It can be found that the abrasive wear of ball joint largely depends on the relative sliding velocity from the experiments. This will probably affectthe dynamics performance and the impact force, which will also cause the other type of failures.

  7. Fully transparent conformal organic thin-film transistor array and its application as LED front driving.

    Science.gov (United States)

    Cui, Nan; Ren, Hang; Tang, Qingxin; Zhao, Xiaoli; Tong, Yanhong; Hu, Wenping; Liu, Yichun

    2018-02-22

    A fully transparent conformal organic thin-film field-effect transistor array is demonstrated based on a photolithography-compatible ultrathin metallic grid gate electrode and a solution-processed C 8 -BTBT film. The resulting organic field-effect transistor array exhibits a high optical transparency of >80% over the visible spectrum, mobility up to 2 cm 2 V -1 s -1 , on/off ratio of 10 5 -10 6 , switching current of >0.1 mA, and excellent light stability. The transparent conformal transistor array is demonstrated to adhere well to flat and curved LEDs as front driving. These results present promising applications of the solution-processed wide-bandgap organic semiconductor thin films in future large-scale transparent conformal active-matrix displays.

  8. Ego, drives, and the dynamics of internal objects

    Directory of Open Access Journals (Sweden)

    Simon eBoag

    2014-07-01

    Full Text Available This paper addresses the relationship between the ego, id, and internal objects. While ego psychology views the ego as autonomous of the drives, a less well-known alternative position views the ego as constituted by the drives. Based on Freud’s ego-instinct account, this position has developed into a school of thought which postulates that the drives act as knowers. Given that there are multiple drives, this position proposes that personality is constituted by multiple knowers. Following on from Freud, the ego is viewed as a composite sub-set of the instinctual drives (ego-drives, whereas those drives cut off from expression form the id. The nature of the ‘self’ is developed in terms of identification and the possibility of multiple personalities is also established. This account is then extended to object-relations and the explanatory value of the ego-drive account is discussed in terms of the addressing the nature of ego-structures and the dynamic nature of internal objects. Finally, the impact of psychological conflict and the significance of repression for understanding the nature of splits within the psyche are also discussed.

  9. Dimensionality reduction of cellular actuator arrays using the concept of synergy for driving a robotic hand.

    Science.gov (United States)

    Cho, Kyu-Jin; Asada, Harry

    2006-01-01

    This paper presents a method of reducing dimensionality of cellular actuator arrays. The cellular actuator arrays are used to drive a multi-axis system, i.e. robotic hand. The actuator arrays use Segmented Binary Control (SBC) which simplifies the control of nonlinear artificial muscle actuators. Although the SBC simplifies the control, the number of cells required to create motions is increased dramatically, thereby increasing the dimension of the actuator arrays. Therefore, reducing the number of controls, or dimension is needed. The coordinated motion of the robotic hand enables the coupling of actuators. In biological systems, synergies, a strategy of grouping output variables to simplify the control of a large number of muscles and joints is used to explain the coordinated motion created by the muscles. Similarly we can apply this concept to group the cells of the actuator array to be turned on or off together. Each group of cells, called segments can be designed to perform a certain set of desired postures. Data from fifteen different tasks is used in the design. The gathered joint angle data is transformed into actuator displacement data and used to generate a segmentation design of the actuator. For segmentation design, feature extraction method, similar to non-negative matrix factorization with binary filter is proposed. The segmentation design reduces 96 separately controlled segments to 6, while maintaining the ability to accomplish all desired postures. A prototype robotic hand with five fingers, designed and fabricated using the FDM process, is driven with this actuator system.

  10. Optical resonance problem in metamaterial arrays: a lattice dynamics approach.

    Science.gov (United States)

    Liu, Wanguo

    2016-11-30

    A systematic dynamic theory is established to deal with the optical collective resonance in metamaterial arrays. As a reference model, we consider an infinite split ring resonator (SRR) array illuminated by a linearly polarized wave and introduce an N-degree-of-freedom forced oscillator equation to simplify the coupled-mode vibration problem. We derive a strict formula of resonance frequency (RF) and its adjustable range from the steady-state response. Unlike a single SRR possesses invariant RF, it successfully explains the mechanism of RF shift effect in the SRR array when the incident angle changes. Instead of full wave analysis, only one or two adjacent resonance modes can give an accurate response line shape. Our approach is applicable for metallic arrays with any N-particle cell at all incident angles and well matched with numerical results. It provides a versatile way to study the vibration dynamics in optical periodic many-body systems.

  11. Sequential reconstruction of driving-forces from nonlinear nonstationary dynamics

    Science.gov (United States)

    Güntürkün, Ulaş

    2010-07-01

    This paper describes a functional analysis-based method for the estimation of driving-forces from nonlinear dynamic systems. The driving-forces account for the perturbation inputs induced by the external environment or the secular variations in the internal variables of the system. The proposed algorithm is applicable to the problems for which there is too little or no prior knowledge to build a rigorous mathematical model of the unknown dynamics. We derive the estimator conditioned on the differentiability of the unknown system’s mapping, and smoothness of the driving-force. The proposed algorithm is an adaptive sequential realization of the blind prediction error method, where the basic idea is to predict the observables, and retrieve the driving-force from the prediction error. Our realization of this idea is embodied by predicting the observables one-step into the future using a bank of echo state networks (ESN) in an online fashion, and then extracting the raw estimates from the prediction error and smoothing these estimates in two adaptive filtering stages. The adaptive nature of the algorithm enables to retrieve both slowly and rapidly varying driving-forces accurately, which are illustrated by simulations. Logistic and Moran-Ricker maps are studied in controlled experiments, exemplifying chaotic state and stochastic measurement models. The algorithm is also applied to the estimation of a driving-force from another nonlinear dynamic system that is stochastic in both state and measurement equations. The results are judged by the posterior Cramer-Rao lower bounds. The method is finally put into test on a real-world application; extracting sun’s magnetic flux from the sunspot time series.

  12. Harmonia: A Globally Coordinated Garbage Collector for Arrays of Solid-state Drives

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngjae [ORNL; Oral, H Sarp [ORNL; Shipman, Galen M [ORNL; Lee, Junghee [ORNL; Dillow, David A [ORNL; Wang, Feiyi [ORNL

    2011-01-01

    Solid-State Drives (SSDs) offer significant performance improvements over hard disk drives (HDD) on a number of workloads. The frequency of garbage collection (GC) activity is directly correlated with the pattern, frequency, and volume of write requests, and scheduling of GC is controlled by logic internal to the SSD. SSDs can exhibit significant performance degradations when garbage collection (GC) conflicts with an ongoing I/O request stream. When using SSDs in a RAID array, the lack of coordination of the local GC processes amplifies these performance degradations. No RAID controller or SSD available today has the technology to overcome this limitation. This paper presents Harmonia, a Global Garbage Collection (GGC) mechanism to improve response times and reduce performance variability for a RAID array of SSDs. Our proposal includes a high-level design of SSD-aware RAID controller and GGC-capable SSD devices, as well as algorithms to coordinate the global GC cycles. Our simulations show that this design improves response time and reduces performance variability for a wide variety of enterprise workloads. For bursty, write dominant workloads response time was improved by 69% while performance variability was reduced by 71%.

  13. Boost Converter Fed High Performance BLDC Drive for Solar PV Array Powered Air Cooling System

    Directory of Open Access Journals (Sweden)

    Shobha Rani Depuru

    2017-01-01

    Full Text Available This paper proposes the utilization of a DC-DC boost converter as a mediator between a Solar Photovoltaic (SPV array and the Voltage Source Inverters (VSI in an SPV array powered air cooling system to attain maximum efficiency. The boost converter, over the various common DC-DC converters, offers many advantages in SPV based applications. Further, two Brushless DC (BLDC motors are employed in the proposed air cooling system: one to run the centrifugal water pump and the other to run a fan-blower. Employing a BLDC motor is found to be the best option because of its top efficiency, supreme reliability and better performance over a wide range of speeds. The air cooling system is developed and simulated using the MATLAB/Simulink environment considering the steady state variation in the solar irradiance. Further, the efficiency of BLDC drive system is compared with a conventional Permanent Magnet DC (PMDC motor drive system and from the simulated results it is found that the proposed system performs better.

  14. Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator.

    Science.gov (United States)

    2013-10-01

    This research studies the effectiveness of a dynamic message sign (DMS) using a driving : simulator. Over 100 subjects from different socio-economic and age groups were recruited to : drive the simulator under different traffic and driving conditions...

  15. Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator : final report.

    Science.gov (United States)

    2013-10-01

    This research studies the effectiveness of a dynamic message sign (DMS) using a driving : simulator. Over 100 subjects from different socio-economic and age groups were recruited to : drive the simulator under different traffic and driving conditions...

  16. Study on dynamic lifting characteristics of control rod drive mechanism

    International Nuclear Information System (INIS)

    Shen Xiaoyao

    2012-01-01

    Based on the equations of the electric circuit and the magnetic circuit and analysis of the dynamic lifting process for the control rod drive mechanism (CRDM), coupled magnetic-electric-mechanical equations both for the static status and the dynamic status are derived. The analytical method is utilized to obtain the current and the time when the lift starts. The numerical simulation method of dynamic analysis recommended by ASME Code is utilized to simulate the dynamic lifting process of CRDM, and the dynamic features of the system with different design gaps are studied. Conclusions are drawn as: (1) the lifting-start time increases with the design gap, and the time for the lifting process is longer with larger gaps; (2) the lifting velocity increases with time; (3) the lifting acceleration increases with time, and with smaller gaps, the impact acceleration is larger. (author)

  17. Dynamic Adaptive Neural Network Arrays: A Neuromorphic Architecture

    Energy Technology Data Exchange (ETDEWEB)

    Disney, Adam [University of Tennessee (UT); Reynolds, John [University of Tennessee (UT)

    2015-01-01

    Dynamic Adaptive Neural Network Array (DANNA) is a neuromorphic hardware implementation. It differs from most other neuromorphic projects in that it allows for programmability of structure, and it is trained or designed using evolutionary optimization. This paper describes the DANNA structure, how DANNA is trained using evolutionary optimization, and an application of DANNA to a very simple classification task.

  18. Moving vortex phases, dynamical symmetry breaking, and jamming for vortices in honeycomb pinning arrays

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia [Los Alamos National Laboratory

    2008-01-01

    We show using numerical simulations that vortices in honeycomb pinning arrays can exhibit a remarkable variety of dynamical phases that are distinct from those found for triangular and square pinning arrays. In the honeycomb arrays, it is possible for the interstitial vortices to form dimer or higher n-mer states which have an additional orientational degree of freedom that can lead to the formation of vortex molecular crystals. For filling fractions where dimer states appear, a dynamical symmetry breaking can occur when the dimers flow in one of two possible alignment directions. This leads to transport in the direction transverse to the applied drive. We show that dimerization produces distinct types of moving phases which depend on the direction of the driving force with respect to the pinning lattice symmetry. When the dimers are driven along certain directions, a reorientation of the dimers can produce a jamming phenomenon which results in a strong enhancement in the critical depinning force. The jamming can also cause unusual effects such as an increase in the critical depinning force when the size of the pinning sites is reduced.

  19. Nonequilibriun Dynamic Phases of Driven Vortex Lattices in Superconductors with Periodic Pinning Arrays

    Science.gov (United States)

    Reichhardt, C.; Olson, C. J.; Nori, F.

    1998-03-01

    We present results from extensive simulations of driven vortex lattices interacting with periodic pinning arrays. Changing an applied driving force produces an exceptionally rich variety of distinct dynamic phases which include over a dozen well defined plastic flow phases. Transitions between different dynamical phases are marked by sharp jumps in the V(I) curves that coincide with distinct changes in the vortex trajectories and vortex lattice order. A series of dynamical phase diagrams are presented which outline the onset of the different dynamical phases (C. Reichhardt, C.J. Olson, and F. Nori, Phys. Rev. Lett. 78), 2648 (1997); and to be published. Videos are avaliable at http://www-personal.engin.umich.edu/ñori/. Using force balance arguments, several of the phase boundaries can be derived analyticaly.

  20. Plasma dynamics in aluminium wire array Z-pinch implosions

    International Nuclear Information System (INIS)

    Bland, S.N.

    2001-01-01

    The wire array Z-pinch is the world's most powerful laboratory X-ray source. An achieved power of ∼280TW has generated great interest in the use of these devices as a source of hohlraum heating for inertial confinement fusion experiments. However, the physics underlying how wire array Z-pinches implode is not well understood. This thesis presents the first detailed measurements of plasma dynamics in wire array experiments. The MAGPIE generator, with currents of up to 1.4MA, 150ns 10-90% rise-time, was used to implode arrays of 16mm diameter typically containing between 8 and 64 15μm aluminium wires. Diagnostics included: end and side-on laser probing with interferometry, schlieren and shadowgraphy channels; radial and axial streak photography; gated X-ray imaging; XUV and hard X-ray spectrometry; filtered XRDs and diamond PCDs; and a novel X-ray backlighting system to probe high density plasma. It was found that the plasma formed from the wires consisted of cold, dense cores, which ablated producing hot, low density coronal plasma. After an initial acceleration around the cores, coronal plasma streams flowed force-free towards the axis, with an instability wavelength determined by the core size. At ∼50% of the implosion time, the streams collided on axis forming a precursor plasma which appeared to be uniform, stable, and inertially confined. The existence of core-corona structure significantly affected implosion dynamics. For arrays with <64 wires, the wire cores remained in their original positions until ∼80% of the implosion time before accelerating rapidly. At 64 wires a transition in implosion trajectories to 0-D like occurred indicating a possible merger of current carrying plasma close to the cores - the cores themselves did not merge. During implosion, the cores initially developed uncorrelated instabilities that then transformed into a longer wavelength global mode of instability. The study of nested arrays (2 concentric arrays, one inside the other

  1. Bicycle drive system dynamics: theory and experimental validation.

    Science.gov (United States)

    Fregly, B J; Zajac, F E; Dairaghi, C A

    2000-08-01

    Bicycle pedaling has been studied from both a motor control and an equipment setup and design perspective. In both cases, although the dynamics of the bicycle drive system may have an influence on the results, a thorough understanding of the dynamics has not been developed. This study pursued three objectives related to developing such an understanding. The first was to identify the limitations of the inertial/frictional drive system model commonly used in the literature. The second was to investigate the advantages of an inertial/frictional/compliant model. The final objective was to use these models to develop a methodology for configuring a laboratory ergometer to emulate the drive system dynamics of road riding. Experimental data collected from the resulting road-riding emulator and from a standard ergometer confirmed that the inertial/frictional model is adequate for most studies of road-riding mechanics or pedaling coordination. However, the compliant model was needed to reproduce the phase shift in crank angle variations observed experimentally when emulating the high inertia of road riding. This finding may be significant for equipment setup and design studies where crank kinematic variations are important or for motor control studies where fine control issues are of interest.

  2. Diffusive Dynamics of Nanoparticles in Arrays of Nanoposts

    KAUST Repository

    He, Kai

    2013-06-25

    The diffusive dynamics of dilute dispersions of nanoparticles of diameter 200-400 nm were studied in microfabricated arrays of nanoposts using differential dynamic microscopy and single particle tracking. Posts of diameter 500 nm and height 10 μm were spaced by 1.2-10 μm on a square lattice. As the spacing between posts was decreased, the dynamics of the nanoparticles slowed. Moreover, the dynamics at all length scales were best represented by a stretched exponential rather than a simple exponential. Both the relative diffusivity and the stretching exponent decreased linearly with increased confinement and, equivalently, with decreased void volume. The slowing of the overall diffusive dynamics and the broadening distribution of nanoparticle displacements with increased confinement are consistent with the onset of dynamic heterogeneity and the approach to vitrification. © 2013 American Chemical Society.

  3. A new dynamic electrochemical transduction mechanism for interdigitated array microelectrodes.

    Science.gov (United States)

    Zhu, Xiaoshan; Choi, Jin-Woo; Ahn, Chong H

    2004-12-01

    A dynamic electrochemical transduction mechanism for interdigitated array microelectrodes using an electrical charge pumping method is presented in this paper. In this dynamic transduction mechanism, a charged external capacitor is used as the charge supplier for the electrochemical reaction of the reversible redox species at the interdigitated array electrodes. The charges stored in the capacitor are consumed as the electrochemical reaction current, which causes the capacitor potential decay. The theoretical analysis has shown that the species concentration has a decisive effect on the capacitor potential decay, and therefore the characteristics of the capacitor potential decay are recorded and analyzed to evaluate the concentration of redox species. The new transduction mechanism has the advantages of achieving high sensitivity with small sensor area and simplifying the measurement instrumentation. As a demonstration device, interdigitated array microelectrodes (approximately 0.2 mm(2) electrode surface area) have been fabricated and successfully characterized using p-aminophenol as the redox species under this dynamic mechanism. The detection limit of p-aminophenol was calculated to be approximately 4 x 10(-7) M for the sensor with the new dynamic transduction mechanism.

  4. Current Drive operation in a In-blanket ICRF Ring Array

    Directory of Open Access Journals (Sweden)

    G.Bosia

    2017-01-01

    Full Text Available The currently predicted Current Drive (CDefficiency in a tokamak reactor plasma is χCD ≤ 50 kA/MW for all auxiliary systems (NBCD, ICCD, ECCD. This would imply a relatively low reactor Q = Pelectric /Pauxiliary and an extremely high power density (>10 MW/m2 at the plasma boundary, if injected through the vacuum vessel ports or by in-port launchers.. In a previous paper the concept of an Ion Cyclotron Ring Array (RA of many elements, integrated in the reactor blanket first wall was proposed. An analysis of this RA operating in steady state Fast Wave Current Drive (FW CD with all elements individually controlled in magnitude and phase is presented in this paper. For CD operation the RA is operated at low frequency (f ≈ 20MHz so as to avoid the otherwise overwhelming RF power absorption by ions and α-particles. It is shown that the RA would feature a very directive radiation spectrum, a low power density operation (avoiding the drawbacks associated with high AC and DC potentials and a potentially high flexibility of operation..

  5. Current Drive operation in a In-blanket ICRF Ring Array

    Science.gov (United States)

    Bosia, G.; Ragona, R.

    2017-10-01

    The currently predicted Current Drive (CD)efficiency in a tokamak reactor plasma is χCD ≤ 50 kA/MW for all auxiliary systems (NBCD, ICCD, ECCD). This would imply a relatively low reactor Q = Pelectric /Pauxiliary and an extremely high power density (>10 MW/m2) at the plasma boundary, if injected through the vacuum vessel ports or by in-port launchers.. In a previous paper the concept of an Ion Cyclotron Ring Array (RA) of many elements, integrated in the reactor blanket first wall was proposed. An analysis of this RA operating in steady state Fast Wave Current Drive (FW CD) with all elements individually controlled in magnitude and phase is presented in this paper. For CD operation the RA is operated at low frequency (f ≈ 20MHz) so as to avoid the otherwise overwhelming RF power absorption by ions and α-particles. It is shown that the RA would feature a very directive radiation spectrum, a low power density operation (avoiding the drawbacks associated with high AC and DC potentials) and a potentially high flexibility of operation..

  6. Sliding Adhesion Dynamics of Isolated Gecko Setal Arrays

    Science.gov (United States)

    Sponberg, Simon; Autumn, Kellar

    2003-03-01

    The tokay gecko (Gekko gecko) can adhere to nearly any surface through van der Waals interactions of the specialized setae (b-keratin "hairs") of its toe pads. Our recent research has suggested that a gecko is substantially overbuilt for static adhesion requiring as little as 0.03of its theoretical adhesive capacity. We performed the first sliding adhesion experiments on this novel biological adhesive to determine its response to dynamic loading. We isolated arrays of setae and constructed a precision controlled Robo-toe to study sliding effects. Our results indicate that, unlike many typical adhesives, gecko setal arrays exhibit an increased frictional force upon sliding (mk > ms) which further increases with velocity, suggesting that perturbation rejection may be an evolutionary design principle underlying the evolution of the gecko adhesive. We compare these dynamic properties with those of other adhesives and explore the impacts of these results on the design of artificial adhesives.

  7. Gait Dynamics Sensing Using IMU Sensor Array System

    Directory of Open Access Journals (Sweden)

    Slavomir Kardos

    2017-01-01

    Full Text Available The article deals with a progressive approach in gait sensing. It is incorporated by IMU (Inertia Measurement Unit complex sensors whose field of acting is mainly the motion sensing in medicine, automotive and other industry, self-balancing systems, etc. They allow acquiring the position and orientation of an object in 3D space. Using several IMU units the sensing array for gait dynamics was made. Based on human gait analysis the 7-sensor array was designed to build a gait motion dynamics sensing system with the possibility of graphical interpretation of data from the sensing modules in real-time graphical application interface under the LabVIEW platform. The results of analyses can serve as the information for medical diagnostic purposes. The main control part of the system is microcontroller, whose function is to control the data collection and flow, provide the communication and power management.

  8. Dynamic modelling of tearing mode stabilization by RF current drive

    International Nuclear Information System (INIS)

    Giruzzi, G.; Zabiego, M.; Gianakon, T.A.; Garbet, X.; Bernabei, S.

    1998-01-01

    The theory of tearing mode stabilization in toroidal plasmas by RF-driven currents that are modulated in phase with the island rotation is investigated. A time scale analysis of the phenomena involved indicates that transient effects, such as finite time response of the driven currents, island rotation during the power pulses, and the inductive response of the plasma, are intrinsically important. A dynamic model of such effects is developed, based on a 3-D Fokker-Planck code coupled to both the electric field diffusion and the island evolution equations. Extensive applications to both Electron Cyclotron and Lower Hybrid current drive in ITER are presented. (author)

  9. Influence of unsteady aerodynamics on driving dynamics of passenger cars

    Science.gov (United States)

    Huemer, Jakob; Stickel, Thomas; Sagan, Erich; Schwarz, Martin; Wall, Wolfgang A.

    2014-11-01

    Recent approaches towards numerical investigations with computational fluid dynamics methods on unsteady aerodynamic loads of passenger cars identified major differences compared with steady-state aerodynamic excitations. Furthermore, innovative vehicle concepts such as electric-vehicles or hybrid drives further challenge the basic layout of passenger cars. Therefore, the relevance of unsteady aerodynamic loads on cross-wind stability of changing basic vehicle architectures should be analysed. In order to assure and improve handling and ride characteristics at high velocity of the actual range of vehicle layouts, the influence of unsteady excitations on the vehicle response was investigated. For this purpose, a simulation of the vehicle dynamics through multi-body simulation was used. The impact of certain unsteady aerodynamic load characteristics on the vehicle response was quantified and key factors were identified. Through a series of driving simulator tests, the identified differences in the vehicle response were evaluated regarding their significance on the subjective driver perception of cross-wind stability. Relevant criteria for the subjective driver assessment of the vehicle response were identified. As a consequence, a design method for the basic layout of passenger cars and chassis towards unsteady aerodynamic excitations was defined.

  10. Dynamic Phases in Driven Vortex Lattices in Superconductors with Periodic Pinning Arrays.

    Science.gov (United States)

    Reichhardt, C.; Olson, C. J.; Nori, F.

    1997-03-01

    In an extensive series of simulations of driven vortices interacting with periodic pinning arrays, an extremely rich variety of novel plastic flow phases, very distinct from those observed in random arrays, are found as a function of applied driving force. We show that signatures of the transitions between these different dynamical phases appear as pronounced jumps and dips in the I-V curves, coinciding with marked changes in the microscopic structure and flow behavior of the vortex lattice. When the number of vortices is greater than the number of pinning sites, we observe up to six distinct dynamical phases, including a pinned phase, a flow of interstitial vortices between pinned vortices, a disordered flow, a 1D flow along the pinning rows, and a homogeneous flow. By varying a wide range of microscopic pinning parameters, including pinning strength, size, density, and degree of ordering, as well as varying temperature and commensurability, we obtain a series of dynamic phase diagrams. nori>A short video will also be presented to highlight these different dynamic phases.

  11. Development of a solar array drive mechanism for micro-satellite platforms

    Science.gov (United States)

    Galatis, Giorgos; Guo, Jian; Buursink, Jeroen

    2017-10-01

    Photovoltaic solar array (PVSA) systems are the most widely used method for spacecraft power generation. However, in many satellite missions, the optimum orientation of the PVSA system is not always compatible with that of the payload orientation. Many methods, have been examined in the past to overcome this problem. Up to date, the most widely used active method for large costly satellites is the Solar Array Drive Mechanism (SADM). The SADM serves as the interface between the satellite body and the PVSA subsystem, enabling the decoupling of their spatial orientation. Nonetheless, there exists a research and development gap for such systems regarding low cost micro-satellites. During the literature study of this paper, individual orbital parameters of various micro-satellites have been extracted and compared to the rotational freedom of the corresponding SADMs used. The findings demonstrated that the implemented SADMs are over designed. It is therefore concluded that these components are not tailored made for each spacecraft mission individually, but rather, exhibit a generic design to full fill a majority of mission profiles and requirements. Motivated by the above analysis, the cardinal objective of the current research is to develop a low cost mechanism that will be precisely tailored for the use of a low Earth orbit (LEO) micro-satellite platform orbiting in altitudes of 500 - 1000km . The design of the mechanism may vary from the existing miniaturized SADMs. For example, the preliminary analysis of the current research suggests, that the conventional use of the slip ring system as the electronic transfer unit can be replaced by a seMI Orientation Unit (MIOU). Systems engineering tools for concept generation and selection have been used. In addition, simulation and mathematical modelling have been implemented on component and system level, to accurately predict the behaviour of the system under various modes of operation. The production and system testing of

  12. Dynamics of underdamped Josephson arrays in a magnetic field

    International Nuclear Information System (INIS)

    Octavio, M.; Whan, C.B.; Geigenmueller, U.; Lobb, C.J.

    1994-01-01

    We present simulations of the dynamics of underdamped classical Josephson arrays for values of the flux quanta per unit cell f=1/2. We find the dynamics of this system to be quite rich. The I-V characteristics are found to have two distinct regime as the damping is increased. At low voltages the current-voltage characteristics exhibit a regime which we characterize as flux-flow-like since it is dominated by the motion of the vortex superlattice. This regime may exhibit chaotic-like behavior as the damping parameter is increased. At high voltages the characteristics jump to an ohmic-like state in which the junctions are all oscillating. We present a potential model which is quite useful in understanding the dynamics of the system. (orig.)

  13. A sensor array system for monitoring moisture dynamics inunsaturated soil

    Energy Technology Data Exchange (ETDEWEB)

    Salve, R.; Cook, P.J.

    2007-05-15

    To facilitate investigations of moisture dynamics inunsaturated soil, we have developed a technique to qualitatively monitorpatterns of saturation changes. Field results suggest that this device,the sensor array system (SAS), is suitable for determining changes inrelative wetness along vertical soil profiles. The performance of theseprobes was compared with that of the time domain reflectometry (TDR)technique under controlled and field conditions. Measurements from bothtechniques suggest that by obtaining data at high spatial and temporalresolution, the SAS technique was effective in determining patterns ofsaturation changes along a soil profile. In addition, hardware used inthe SAS technique was significantly cheaper than the TDR system, and thesensor arrays were much easier to install along a soilprofile.

  14. Electroacoustics: A New Mechanism for Driving Individually Addressable Jetting and Other Microfluidic Manipulations in Multiwell Arrays

    Science.gov (United States)

    Yeo, Leslie; Rezk, Amgad

    2017-11-01

    The low take-up of microfluidic technology at the laboratory bench despite 25 years of advances can be attributed to the reluctance of practitioners to adopt new and sophisticated technology, which requires substantial retraining, as well as the large investments that have already been made in the vast array of existing laboratory equipment. A way to circumvent this is to design microfluidic technology to retrofit existing laboratory technology such as microscope stages, microplate readers, etc. This is however not without challenge as existing microfluidic devices themselves often require large ancillary equipment to drive fluidic actuation/detection, which are not always amenable to integration into these existing laboratory formats. We have developed a low-cost and scalable modular plug-and-play microplatform that facilitates individual addressability of each well in a microarray plate for sample dispensing, mixing and preconcentration, as well as its ejection via jetting/nebulisation for subsequent analysis. As this cannot be achieved using standard acoustofluidics, we have developed a new electroacoustic mechanism that allows the transmission of high frequency sound waves into each well while uniquely confining the electric field off the piezoelectric chip.

  15. Mass accretion and nested array dynamics from Ni-Clad Ti-Al wire array Z pinches

    International Nuclear Information System (INIS)

    Jones, Brent Manley; Jennings, Christopher A.; Coverdale, Christine Anne; Cuneo, Michael Edward; Maron, Yitzhak; LePell, Paul David; Deeney, Christopher

    2010-01-01

    Analysis of 50 mm diameter wire arrays at the Z Accelerator has shown experimentally the accretion of mass in a stagnating z pinch and provided insight into details of the radiating plasma species and plasma conditions. This analysis focused on nested wire arrays with a 2:1 (outeninner) mass, radius, and wire number ratio where Al wires were fielded on the outer array and Ni-clad Ti wires were fielded on the inner array.In this presentation, we will present analysis of data from other mixed Al/Ni-clad Ti configurations to further evaluate nested wire array dynamics and mass accretion. These additional configurations include the opposite configuration to that described above (Ni-clad Ti wires on the outer array, with Al wires on the inner array) as well as higher wire number Al configurations fielded to vary the interaction of the two arrays. These same variations were also assessed for a smaller diameter nested array configuration (40 mm). Variations in the emitted radiation and plasma conditions will be presented, along with a discussion of what the results indicate about the nested array dynamics. Additional evidence for mass accretion will also be presented.

  16. Tooth modification and dynamic performance of the cycloidal drive

    Science.gov (United States)

    Ren, Zhong-Yi; Mao, Shi-Min; Guo, Wen-Chao; Guo, Zheng

    2017-02-01

    A new method of cycloid disc tooth modification is presented in this paper. Its main idea is to design the modification clearance curves to adapt to different modification targets. A detailed procedure of the new modification clearance curve, which can be defined by adjusting the position of 5 key points is developed. Numerical experiments are carried out to verify the effectiveness of the new method. A Multi-DOF nonlinear dynamic model of cycloidal speed reducer is established, then the cycloid disc rotational displacement and rotational velocity versus time of different modification clearance are solved by the Runge-kutta numerical method. The results show that this method can improve the carrying capability of cycloidal drive, eliminate noise and vibration and develop the transmission accuracy.

  17. Dynamics of Energy Transfer in Quantum Dot Arrays

    Science.gov (United States)

    Al-Ahmadi, A. N.; Ulloa, S. E.

    2004-04-01

    Förster-type coupling is one of the most important mechanisms that influence the energy transport properties in a quantum dot array. We explore this mechanism by calculating the coupling strength V_F, and by studying the dynamics of the exciton state created in an array of quantum dots using the time evolution of the density matrix approach. We first estimate the coupling strength VF of Förster interaction based on microscopic descriptions of the exciton levels in the quantum dot. We study this parameter for different materials (CdS, CdSe,InP, and GaAs) as function of the dot size. The results show that the maximum value of VF depends on the specific sizes and that each material has optimal coupling for different pairs of quantum dot radii. Other key parameters that govern energy transport are determined for various materials and sizes of quantum dots. Second, we consider a model of coupled quantum dots with two exciton levels in each dot, one optically passive and another active. Analysis of the population of each level when the Förster channel is opened shows this is responsible for interesting physical behavior in different coupling regimes. Realistic parameters used to study the dynamics of the exciton state for dimer and trimer quantum dot clusters, allow us direct comparison with recent experiments by Klimov et al. Supported by US DOE, and Indiana 21^st Century Fund Research and Technology.

  18. A Dynamic Control Strategy for Hybrid Electric Vehicles Based on Parameter Optimization for Multiple Driving Cycles and Driving Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Zhenzhen Lei

    2017-01-01

    Full Text Available The driving pattern has an important influence on the parameter optimization of the energy management strategy (EMS for hybrid electric vehicles (HEVs. A new algorithm using simulated annealing particle swarm optimization (SA-PSO is proposed for parameter optimization of both the power system and control strategy of HEVs based on multiple driving cycles in order to realize the minimum fuel consumption without impairing the dynamic performance. Furthermore, taking the unknown of the actual driving cycle into consideration, an optimization method of the dynamic EMS based on driving pattern recognition is proposed in this paper. The simulation verifications for the optimized EMS based on multiple driving cycles and driving pattern recognition are carried out using Matlab/Simulink platform. The results show that compared with the original EMS, the former strategy reduces the fuel consumption by 4.36% and the latter one reduces the fuel consumption by 11.68%. A road test on the prototype vehicle is conducted and the effectiveness of the proposed EMS is validated by the test data.

  19. Driving-induced metamorphosis of transport in arrays of coupled resonators

    Science.gov (United States)

    Li, Huanan; Kottos, Tsampikos; Shapiro, Boris

    2018-02-01

    We propose a driving scheme, wherein different parts of a system are driven with different, generally incommensurate, frequencies. Such driving provides a flexible handle to control various properties of the system and to obtain new types of effective (static) Hamiltonians with arbitrary static on-site potential, be it deterministic or random. This allows us to obtain reconfigurable changes in transport, from ballistic to localized (including sub- and superdiffusion), depending on the driving protocol. The versatile reconfigurability extends also to scattering from (locally) driven extended targets. We demonstrate our scheme using an analytically solvable example of a one-dimensional tight-binding chain with appropriately driven couplings between nearby sites.

  20. Numerical study of self-field effects on dynamics of Josephson-junction arrays

    International Nuclear Information System (INIS)

    Phillips, J.R.; Van der Zant, H.S.J.; White, J.; Orlando, T.P.

    1994-01-01

    We consider the influence of self-induced magnetic fields on dynamic properties of arrays of resistively and capacitively shunted Josephson junctions. Self-field effects are modeled by including mutual inductance interactions between every cell in the array. We find that it is important to include all mutual inductance interactions in order to understand the dynamic properties of the array, in particular subharmonic structure arising under AC current bias. (orig.)

  1. Dynamical phase transition in a fully frustrated Josephson array on a square lattice

    International Nuclear Information System (INIS)

    Fisher, K. D.; Stroud, D.; Janin, L.

    1999-01-01

    We study dynamical phase transitions at temperature T=0 in a fully frustrated square Josephson junction array subject to a driving current density, which has nonzero components i x , i y parallel to both axes of the lattice. Our numerical results show clear evidence for three dynamical phases: a pinned vortex lattice characterized by zero time-averaged voltages x > t and y > t , a ''plastic'' phase in which both x > t and y > t are nonzero, and a moving lattice phase in which only one of the time-average voltage components is nonzero. The last of these has a finite transverse critical current: if a current is applied in the x direction, a nonzero transverse current density i y is required before y > t becomes nonzero. The voltage traces in the moving lattice phase are periodic in time. By contrast, the voltages in the plastic phase have continuous power spectra that are weakly dependent on frequency. This phase diagram is found numerically to be qualitatively unchanged by the presence of weak disorder. We also describe two simple analytical models that recover some, but not all, the characteristics of the three dynamical phases, and of the phase diagram calculated numerically. (c) 1999 The American Physical Society

  2. Electromechanical dynamic analysis for the drum driving system of the long-wall shearer

    Directory of Open Access Journals (Sweden)

    Changzhao Liu

    2015-10-01

    Full Text Available The drum driving system is one of the weakest parts of the long-wall shearer, and some methods are also needed to monitor and control the long-wall shearer to adapt to the important trend of unmanned operation in future mining systems. Therefore, it is essential to conduct an electromechanical dynamic analysis for the drum driving system of the long-wall shearer. First, a torsional dynamic model of planetary gears is proposed which is convenient to be connected to the electric motor model for electromechanical dynamic analysis. Next, an electromechanical dynamic model for the drum driving system is constructed including the electric motor, the gear transmission system, and the drum. Then, the electromechanical dynamic characteristics are simulated when the shock loads are acted on the drum driving system. Finally, some advices are proposed for improving the reliability, monitoring the operating state, and choosing the control signals of the long-wall shearer based on the simulation.

  3. DYNAMIC ANALYSIS OF HYDRAULIC DRIVE OF TILTING PLATFORM MECHANISM OF DUMP TRUCK

    Directory of Open Access Journals (Sweden)

    P. Kishkevich

    2011-01-01

    Full Text Available Object of research – hydraulic drive of tilting platform mechanism of dump truck. We pro-pose a dynamic model of the hydraulic system. The model takes into account the cyclic operation (lifting, lowering the platform.

  4. DYNAMIC ANALYSIS OF HYDRAULIC DRIVE OF TILTING PLATFORM MECHANISM OF DUMP TRUCK

    OpenAIRE

    P. Kishkevich; A. Safonau; I. Selivonchik; P. Bartosh

    2011-01-01

    Object of research – hydraulic drive of tilting platform mechanism of dump truck. We pro-pose a dynamic model of the hydraulic system. The model takes into account the cyclic operation (lifting, lowering the platform).

  5. In The Truman Show: Generating Dynamic Scenarios in a Driving Simulator

    NARCIS (Netherlands)

    Wassink, I.; van Dijk, B.; van Dijk, Elisabeth M.A.G.; Zwiers, Jakob; Nijholt, Antinus; Brugman, A.M.

    Using a movie set metaphor, this software framework increases a driving simulator’s effectiveness by dynamically controlling traffic scenarios. It uses agent protocols to make the system extensible, maintainable, and easy to understand.

  6. Beam Dynamics Simulation for the CTF3 Drive Beam Accelerator

    CERN Document Server

    Schulte, Daniel

    2000-01-01

    A new CLIC Test Facility (CTF3) at CERN will serve to study the drive beam generation for the Compact Linear Collider (CLIC). CTF3 has to accelerate a 3.5 A electron beam in almost fully-loaded structures. The pulse contains more than 2000 bunches, one in every second RF bucket, and has a length of more than one microsecond. Different options for the lattice of the drive-beam accelerator are presented, based on FODO-cells and triplets as well as solenoids. The transverse stability is simulated, including the effects of beam jitter, alignment and beam-based correction.

  7. Optimal Charging of Electric Drive Vehicles: A Dynamic Programming Approach

    DEFF Research Database (Denmark)

    Delikaraoglou, Stefanos; Capion, Karsten Emil; Juul, Nina

    2013-01-01

    With the integration of fluctuating renewable production into the electricity system, electric-drive vehicles may contribute to the resulting need for flexibility, given that the market conditions provide sufficient economic incentive. To investigate this, we consider the short-term management...

  8. Physicochemical characteristics and droplet impact dynamics of superhydrophobic carbon nanotube arrays.

    Science.gov (United States)

    Aria, Adrianus I; Gharib, Morteza

    2014-06-17

    The physicochemical and droplet impact dynamics of superhydrophobic carbon nanotube arrays are investigated. These superhydrophobic arrays are fabricated simply by exposing the as-grown carbon nanotube arrays to a vacuum annealing treatment at a moderate temperature. This treatment, which allows a significant removal of oxygen adsorbates, leads to a dramatic change in wettability of the arrays, from mildly hydrophobic to superhydrophobic. Such change in wettability is also accompanied by a substantial change in surface charge and electrochemical properties. Here, the droplet impact dynamics are characterized in terms of critical Weber number, coefficient of restitution, spreading factor, and contact time. Based on these characteristics, it is found that superhydrophobic carbon nanotube arrays are among the best water-repellent surfaces ever reported. The results presented herein may pave a way for the utilization of superhydrophobic carbon nanotube arrays in numerous industrial and practical applications, including inkjet printing, direct injection engines, steam turbines, and microelectronic fabrication.

  9. Preliminary Experimental Results for Indirect Vector-Control of Induction Motor Drives with Forced Dynamics

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2003-01-01

    Full Text Available The contribution presents an extension of indirect vector control of electric drives employing induction motors to 'Forced Dynamic Control'. This method of control offers an accurate realisation of dynamic response profiles, which can be selected by the user. The developed system can be integrated into a drive with a shaft position encoder or a shaft sensoriess drive, in which only the stator currents are measured. The applied stator voltages are determined by a computed inverter switching algorithm. Simulation results and preliminary experimental results for indirect vector control of an idle running induction motor indicate good agreement with the theoretical predictions.

  10. Influence of Unsteady Aerodynamics on Driving Dynamics of Passenger Cars

    OpenAIRE

    Huemer, J.; Stickel, T.; Sagan, E.; Schwarz, M.; Wall, W.A.

    2015-01-01

    Recent approaches towards numerical investigations with CFD-Methods on unsteady aerodynamic loads of passenger cars identified major differences compared to steady state aerodynamic excitations. Furthermore innovative vehicle concepts like electric-vehicles or hybrid drives further challenge the basic layout of passenger cars. Therefore the relevance of unsteady aerodynamic loads on cross-wind stability of changing basic vehicle architectures should be analysed. In order to assure and improve...

  11. Large Volume Coagulation Utilizing Multiple Cavitation Clouds Generated by Array Transducer Driven by 32 Channel Drive Circuits

    Science.gov (United States)

    Nakamura, Kotaro; Asai, Ayumu; Sasaki, Hiroshi; Yoshizawa, Shin; Umemura, Shin-ichiro

    2013-07-01

    High-intensity focused ultrasound (HIFU) treatment is a noninvasive treatment, in which focused ultrasound is generated outside the body and coagulates a diseased tissue. The advantage of this method is minimal physical and mental stress to the patient, and the disadvantage is the long treatment time caused by the smallness of the therapeutic volume by a single exposure. To improve the efficiency and shorten the treatment time, we are focusing attention on utilizing cavitation bubbles. The generated microbubbles can convert the acoustic energy into heat with a high efficiency. In this study, using the class D amplifiers, which we have developed, to drive the array transducer, we demonstrate a new method to coagulate a large volume by a single HIFU exposure through generating cavitation bubbles distributing in a large volume and vibrating all of them. As a result, the coagulated volume by the proposed method was 1.71 times as large as that of the conventional method.

  12. Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

    DEFF Research Database (Denmark)

    Dmytriiev, O.; Al-Jarah, U.A.S.; Gangmei, P.

    2013-01-01

    between experimental and simulated spectra are observed when the field is applied perpendicular to the nanowire axes. The dependence of the magnetic excitation spectra upon the array packing density is explored, and dispersion curves for spin waves propagating within the array parallel to the nanowire...... axis are presented. Finally, a tunneling of end modes through the middle region of the nanowires was observed. The tunneling is more efficient for wires forming densely packed arrays, as a result of the extended penetration of the dynamic demagnetizing fields into the middle of the wires and due...... to the lowering of the tunneling barrier by the static demagnetizing field of the array....

  13. Inverse Dynamic Analysis for Various Drivings in Kinematic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Hoon [Pusan Nat’l Univ., Busan (Korea, Republic of)

    2017-09-15

    Analysis of actuating forces and joint reaction forces are essential to determine the capacity of actuators, to control the mechanical system and to design its components. This paper presents an algorithm that calculates actuating forces(or torques), depending on the various types of driving constraints, in order to produce a given system motion in the joint coordinate space. The joint coordinates are used as the generalized coordinates of a kinematic system. System equations of motion and constraint acceleration equations are transformed from the Cartesian coordinate space to the joint coordinate space using the velocity transformation method. A numerical example is carried out to verify the algorithm proposed.

  14. Dynamics control of autonomous vehicle at driving limits and experiment on an autonomous formula racing car

    Science.gov (United States)

    Ni, Jun; Hu, Jibin

    2017-06-01

    In this paper, a novel dynamics controller for autonomous vehicle to simultaneously control it to the driving limits and follow the desired path is proposed. The dynamics controller consists of longitudinal and lateral controllers. In longitudinal controller, the G-G diagram is utilized to describe the driving and handling limits of the vehicle. The accurate G-G diagram is obtained based on phase plane approach and a nonlinear vehicle dynamic model with accurate tyre model. In lateral controller, the tyre cornering stiffness is estimated to improve the robustness of the controller. The stability analysis of the closed-looped error dynamics shows that the controller remains stable against parameters uncertainties in extreme condition such as tyre saturation. Finally, an electric autonomous Formula race car developed by the authors is used to validate the proposed controller. The autonomous driving experiment on an oval race track shows the efficiency and robustness of the proposed controller.

  15. A Refined Numerical Simulation on Dynamic Behavior of Roller Chain Drives

    Directory of Open Access Journals (Sweden)

    H. Zheng

    2004-01-01

    Full Text Available A refined numerical analysis of the dynamic behavior of roller chain drives is performed considering the roller assembly as a three-layer structure with mechanical clearance between each two of the mechanical components. Instead of using analytical method, explicit finite element technique is utilized for modeling and simulating the dynamic behavior of chain drives. The complete standard geometry of sprockets and all components of chain links are used in the developed model with minor geometry simplification. A primary goal is to achieve a more complete understanding of the dynamic behavior of chain drives especially in the transient vibration response of the engaging rollers, which is crucial for noise emission calculation. The simulated velocity response of the engaging rollers and roller-sprocket contact forces achieved using the full model are compared with what found by the simple model which has been adopted in analytical study of chain roller dynamics.

  16. Collective Quantum Phase-Slip Dynamics in Superconducting Nanowire Arrays

    Science.gov (United States)

    Skacel, Sebastian T.; Voss, Jan N.; Bier, Tobias; Radke, Lucas; Weides, Martin; Rotzinger, Hannes; Mooij, Hans E.; Ustinov, Alexey V.

    2014-03-01

    Superconducting nanowire arrays exhibit quantum phase-slip (QPS) phenomenon if the superconductor has a very high normal-state sheet resistance. We experimentally study QPS effects in arrays of nanowires embedded in a resonant circuit at GHz frequencies. We probe this circuit at ultra-low microwave power, applied flux and mK temperatures. The nanowires are fabricated utilizing aluminium grown in a precisely-controlled oxygen atmosphere. In this way, we aim to control the QPS rate for a given wire width. The wires are defined with conventional electron beam lithography down to a width of 20 nm. We will present the fabrication of the nanowire arrays and first microwave measurements at mK temperatures. Center for Functional Nanostructures, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany.

  17. Driving Ordering Processes in Molecular-Dynamics Simulations

    Science.gov (United States)

    Dittmar, Harro; Kusalik, Peter G.

    2014-05-01

    Self-organized criticality describes the emergence of complexity in dynamical nonequilibrium systems. In this paper we introduce a unique approach whereby a driven energy conversion is utilized as a sampling bias for ordered arrangements in molecular dynamics simulations of atomic and molecular fluids. This approach gives rise to dramatically accelerated nucleation rates, by as much as 30 orders of magnitude, without the need of predefined order parameters, which commonly employed rare-event sampling methods rely on. The measured heat fluxes suggest how the approach can be generalized.

  18. Parallel optical readout of cantilever arrays in dynamic mode

    NARCIS (Netherlands)

    Koelmans, W.W.; van Honschoten, J.W.; de Vries, Jeroen; Vettiger, P.; Abelmann, Leon; Elwenspoek, Michael Curt

    2010-01-01

    Parallel frequency readout of an array of cantilevers is demonstrated using optical beam deflection with a single laser–diode pair. Multi-frequency addressing makes the individual nanomechanical response of each cantilever distinguishable within the received signal. Addressing is accomplished by

  19. The coil array method for creating a dynamic imaging volume.

    Science.gov (United States)

    Smith, Elliot; Freschi, Fabio; Repetto, Maurizio; Crozier, Stuart

    2017-08-01

    Gradient strength and speed are limited by peripheral nerve stimulation (PNS) thresholds. The coil array method allows the gradient field to be moved across the imaging area. This can help reduce PNS and provide faster imaging for image-guided therapy systems such as the magnetic resonance imaging-guided linear accelerator (MRI-linac). The coil array is designed such that many coils produce magnetic fields, which combine to give the desired gradient profile. The design of the coil array uses two methods: either the singular value decomposition (SVD) of a set of field profiles or the electromagnetic modes of the coil surface. Two whole-body coils and one experimental coil were designed to investigate the method. The field produced by the experimental coil was compared to simulated results. The experimental coil region of uniformity (ROU) was moved along the z axis as shown in simulation. The highest observed field deviation was 16.9% at the edge of the ROU with a shift of 35 mm. The whole-body coils showed a median field deviation across all offsets below 5% with an eight-coil basis when using the SVD design method. Experimental results show the feasibility of a moving imaging region within an MRI with a low number of coils in the array. Magn Reson Med 78:784-793, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  20. Weather Conditions Drive Dynamic Habitat Selection in a Generalist Predator

    DEFF Research Database (Denmark)

    Sunde, Peter; Thorup, Kasper; Jacobsen, Lars Bo

    2014-01-01

    Despite the dynamic nature of habitat selection, temporal variation as arising from factors such as weather are rarely quantified in species-habitat relationships. We analysed habitat use and selection (use/availability) of foraging, radio-tagged little owls (Athene noctua), a nocturnal, year-rou...

  1. Triadic closure dynamics drives scaling laws in social multiplex networks

    International Nuclear Information System (INIS)

    Klimek, Peter; Thurner, Stefan

    2013-01-01

    Social networks exhibit scaling laws for several structural characteristics, such as degree distribution, scaling of the attachment kernel and clustering coefficients as a function of node degree. A detailed understanding if and how these scaling laws are inter-related is missing so far, let alone whether they can be understood through a common, dynamical principle. We propose a simple model for stationary network formation and show that the three mentioned scaling relations follow as natural consequences of triadic closure. The validity of the model is tested on multiplex data from a well-studied massive multiplayer online game. We find that the three scaling exponents observed in the multiplex data for the friendship, communication and trading networks can simultaneously be explained by the model. These results suggest that triadic closure could be identified as one of the fundamental dynamical principles in social multiplex network formation. (paper)

  2. Characterization of dynamic change of Fan-delta reservoir properties in water-drive development

    Energy Technology Data Exchange (ETDEWEB)

    Wu Shenghe; Xiong Qihua; Liu Yuhong [Univ. of Petroleum Changping, Beijing (China)

    1997-08-01

    Fan-delta reservoir in Huzhuangji oil field of east China, is a typical highly heterogeneous reservoir. The oil field has been developed by water-drive for 10 years, but the oil recovery is less than 12%, and water cut is over 90%, resulting from high heterogeneity and serious dynamic change of reservoir properties. This paper aims at the study of dynamic change of reservoir properties in water-drive development. Through quantitative imaging analysis and mercury injection analysis of cores from inspection wells, the dynamic change of reservoir pore structure in water-drive development was studied. The results show that the {open_quotes}large pore channels{close_quotes} develop in distributary channel sandstone and become larger in water-drive development, resulting in more serious pore heterogeneity. Through reservoir sensitivity experiments, the rock-fluid reaction in water-drive development is studied. The results show the permeability of some distal bar sandstone and deserted channel sandstone becomes lower due to swelling of I/S clay minerals in pore throats. OD the other hand, the permeability of distributary channel and mouth bar sandstone become larger because the authigenic Koalinites in pore throats are flushed away with the increase of flow rate of injection water. Well-logging analysis of flooded reservoirs are used to study the dynamic change of reservoir properties in various flow units. The distribution of remaining oil is closely related to the types and distribution of flow units.

  3. Spin dynamics and spin-dependent recombination of a polaron pair under a strong ac drive

    Science.gov (United States)

    Malla, Rajesh K.; Raikh, M. E.

    2017-08-01

    We study theoretically the recombination within a pair of two polarons in magnetic field subject to a strong linearly polarized ac drive. Strong drive implies that the Zeeman frequencies of the pair partners are much smaller than the Rabi frequency, so that the rotating wave approximation does not apply. What makes the recombination dynamics nontrivial is that the partners recombine only when they form a singlet S . By admixing singlet to triplets, the drive induces the triplet recombination as well. We calculate the effective decay rate of all four spin modes. Our main finding is that, under the strong drive, the major contribution to the decay of the modes comes from short time intervals when the driving field passes through zero. When the recombination time in the absence of drive is short, fast recombination from S leads to anomalously slow recombination from the other spin states of the pair. We show that, with strong drive, this recombination becomes even slower. The corresponding decay rate falls off as a power law with the amplitude of the drive.

  4. Does visual attention drive the dynamics of bistable perception?

    Science.gov (United States)

    Dieter, Kevin C; Brascamp, Jan; Tadin, Duje; Blake, Randolph

    2016-10-01

    How does attention interact with incoming sensory information to determine what we perceive? One domain in which this question has received serious consideration is that of bistable perception: a captivating class of phenomena that involves fluctuating visual experience in the face of physically unchanging sensory input. Here, some investigations have yielded support for the idea that attention alone determines what is seen, while others have implicated entirely attention-independent processes in driving alternations during bistable perception. We review the body of literature addressing this divide and conclude that in fact both sides are correct-depending on the form of bistable perception being considered. Converging evidence suggests that visual attention is required for alternations in the type of bistable perception called binocular rivalry, while alternations during other types of bistable perception appear to continue without requiring attention. We discuss some implications of this differential effect of attention for our understanding of the mechanisms underlying bistable perception, and examine how these mechanisms operate during our everyday visual experiences.

  5. Dynamic array generation and pattern formation for optical tweezers

    DEFF Research Database (Denmark)

    Mogensen, P.C.; Glückstad, J.

    2000-01-01

    The generalised phase contrast approach is used for the generation of optical arrays of arbitrary beam shape, suitable for applications in optical tweezers for the manipulation of biological specimens. This approach offers numerous advantages over current techniques involving the use of computer-......-generated holograms or diffractive optical elements. We demonstrate a low-loss system for generating intensity patterns suitable for the trapping and manipulation of small particles or specimens....

  6. Position Control of Linear Synchronous Motor Drives with Exploitation of Forced Dynamics Control Principles

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2004-01-01

    Full Text Available Closed-loop position control of mechanisms directly driven by linear synchronous motors with permanent magnets is presented. The control strategy is based on forced dynamic control, which is a form of feedback linearisation, yielding a non-liner multivariable control law to obtain a prescribed linear speed dynamics together with the vector control condition of mutal orthogonality between the stator current and magnetic flux vectors (assuming perfect estimates of the plant parameters. Outer position control loop is closed via simple feedback with proportional gain. Simulations of the design control sysstem, including the drive with power electronic switching, predict the intended drive performance.

  7. Brain Dynamics in Predicting Driving Fatigue Using a Recurrent Self-Evolving Fuzzy Neural Network.

    Science.gov (United States)

    Liu, Yu-Ting; Lin, Yang-Yin; Wu, Shang-Lin; Chuang, Chun-Hsiang; Lin, Chin-Teng

    2016-02-01

    This paper proposes a generalized prediction system called a recurrent self-evolving fuzzy neural network (RSEFNN) that employs an on-line gradient descent learning rule to address the electroencephalography (EEG) regression problem in brain dynamics for driving fatigue. The cognitive states of drivers significantly affect driving safety; in particular, fatigue driving, or drowsy driving, endangers both the individual and the public. For this reason, the development of brain-computer interfaces (BCIs) that can identify drowsy driving states is a crucial and urgent topic of study. Many EEG-based BCIs have been developed as artificial auxiliary systems for use in various practical applications because of the benefits of measuring EEG signals. In the literature, the efficacy of EEG-based BCIs in recognition tasks has been limited by low resolutions. The system proposed in this paper represents the first attempt to use the recurrent fuzzy neural network (RFNN) architecture to increase adaptability in realistic EEG applications to overcome this bottleneck. This paper further analyzes brain dynamics in a simulated car driving task in a virtual-reality environment. The proposed RSEFNN model is evaluated using the generalized cross-subject approach, and the results indicate that the RSEFNN is superior to competing models regardless of the use of recurrent or nonrecurrent structures.

  8. Dynamic Control of Plasmon-Exciton Coupling in Au Nanodisk–J-Aggregate Hybrid Nanostructure Arrays

    KAUST Repository

    Zheng, Yue Bing

    2009-01-01

    We report the dynamic control of plasmon-exciton coupling in Au nanodisk arrays adsorbed with J-aggregate molecules by incident angle of light. The angle-resolved spectra of an array of bare Au nanodisks exhibit continuous shifting of localized surface plasmon resonances. This characteristic enables the production of real-time, controllable spectral overlaps between molecular and plasmonic resonances, and the efficient measurement of plasmon-exciton coupling as a function of wavelength with one or fewer nanodisk arrays. Experimental observations of varying plasmon-exciton coupling match with coupled dipole approximation calculations.

  9. WIMP detection and slow ion dynamics in carbon nanotube arrays

    CERN Document Server

    Cavoto, G.; Cocina, F.; Ferretti, J.; Polosa, A.D.

    2016-06-24

    Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy losses and its transverse momentum approaches the channeling conditions in a single CNT. Therefore, the angle formed between the WIMP wind apparent orientation and the direction of parallel carbon nanotube axes must be properly chosen. We focus on very low ion recoil kinetic energies, related to low mass WIMPs (~ 10 GeV) where most of the existing experiments have low sensitivity. Relying on some exact results on two-dimensional lattices of circular obstacles, we study the low energy ion motion in the transverse plane with ...

  10. Long-term social dynamics drive loss of function in pathogenic bacteria

    DEFF Research Database (Denmark)

    Breum Andersen, Sandra; Marvig, Rasmus Lykke; Molin, Søren

    2015-01-01

    Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly...... social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung...... in the host environment. More generally, we provide an example of how sequence analysis can be used to generate testable hypotheses about selection driving long-term phenotypic changes of pathogenic bacteria in situ....

  11. Weather conditions drive dynamic habitat selection in a generalist predator.

    Directory of Open Access Journals (Sweden)

    Peter Sunde

    Full Text Available Despite the dynamic nature of habitat selection, temporal variation as arising from factors such as weather are rarely quantified in species-habitat relationships. We analysed habitat use and selection (use/availability of foraging, radio-tagged little owls (Athene noctua, a nocturnal, year-round resident generalist predator, to see how this varied as a function of weather, season and availability. Use of the two most frequently used land cover types, gardens/buildings and cultivated fields varied more than 3-fold as a simple function of season and weather through linear effects of wind and quadratic effects of temperature. Even when controlling for the temporal context, both land cover types were used more evenly than predicted from variation in availability (functional response in habitat selection. Use of two other land cover categories (pastures and moist areas increased linearly with temperature and was proportional to their availability. The study shows that habitat selection by generalist foragers may be highly dependent on temporal variables such as weather, probably because such foragers switch between weather dependent feeding opportunities offered by different land cover types. An opportunistic foraging strategy in a landscape with erratically appearing feeding opportunities in different land cover types, may possibly also explain decreasing selection of the two most frequently used land cover types with increasing availability.

  12. Beam dynamics simulations for linacs driving short-wavelength FELs

    International Nuclear Information System (INIS)

    Ferrario, M.; Tazzioli, F.

    1999-01-01

    The fast code HOMDYN has been recently developed, in the framework of the TTF (Tesla test facility) collaboration, in order to study the beam dynamics of linacs delivering high brightness beams as those needed for short wavelength Fel experiments. These linacs are typically driven by radio-frequency photo-injectors, where correlated time dependent space charge effects are of great relevance: these effects cannot be studied by standard beam optics codes (TRACE3D, etc.) and they have been modeled so far by means of multi-particle (Pic or quasistatic) codes requiring heavy cpu time and memory allocations. HOMDYN is able to describe the beam generation at the photo-cathode and the emittance compensation process in the injector even running on a laptop with very modest running rimes (less than a minute). In this paper it is showed how this capability of the code is exploited so to model a whole linac up to the point where the space charge dominated regime is of relevance (200 MeV)

  13. Modeling and Dynamic Analysis of Cutterhead Driving System in Tunnel Boring Machine

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2017-01-01

    Full Text Available Failure of cutterhead driving system (CDS of tunnel boring machine (TBM often occurs under shock and vibration conditions. To investigate the dynamic characteristics and reduce system vibration further, an electromechanical coupling model of CDS is established which includes the model of direct torque control (DTC system for three-phase asynchronous motor and purely torsional dynamic model of multistage gear transmission system. The proposed DTC model can provide driving torque just as the practical inverter motor operates so that the influence of motor operating behavior will not be erroneously estimated. Moreover, nonlinear gear meshing factors, such as time-variant mesh stiffness and transmission error, are involved in the dynamic model. Based on the established nonlinear model of CDS, vibration modes can be classified into three types, that is, rigid motion mode, rotational vibration mode, and planet vibration mode. Moreover, dynamic responses under actual driving torque and idealized equivalent torque are compared, which reveals that the ripple of actual driving torque would aggravate vibration of gear transmission system. Influence index of torque ripple is proposed to show that vibration of system increases with torque ripple. This study provides useful guideline for antivibration design and motor control of CDS in TBM.

  14. Common factors drive disease and coarse woody debris dynamics in forests impacted by sudden oak death

    Science.gov (United States)

    Richard C. Cobb; Maggie N. Chan; Ross K. Meentemeyer; David M. Rizzo

    2011-01-01

    Disease ecology has made important steps in describing how epidemiological processes control the impact of pathogens on populations and communities but fewer field or theoretical studies address disease effects at the ecosystem level. We demonstrate that the same epidemiological mechanisms drive disease intensity and coarse woody debris (CWD) dynamics...

  15. Bringing Hollywood to the Driving School: Dynamic Scenario Generation in Simulations and Games

    NARCIS (Netherlands)

    Wassink, I.; van Dijk, Elisabeth M.A.G.; Zwiers, Jakob; Nijholt, Antinus; Maybury, M.; Stock, O.; Wahlster, W.

    2005-01-01

    In this paper we discuss a framework for simulation software called the movie metaphor. It is applied to the Dutch Driving Simulator for dynamic control of traffic scenarios. This framework resolves software complexity by the use of agent protocols inspired by the way of working on a movie set. It

  16. Dynamic Simulation Research on Chain Drive Mechanism of Corn Seeder Based on ADAMS

    Science.gov (United States)

    Wang, Y. B.; Jia, H. P.

    2017-12-01

    In order to reduce the damage to the chain and improve the seeding quality of the seeding machine, the corn seeder has the characteristics of the seeding quality and some technical indexes in the work of the corn seeding machine. The dynamic analysis of the chain drive mechanism is carried out by using the dynamic virtual prototype. In this paper, the speed of the corn planter is 5km/h, and the speed of the simulated knuckle is 0.1~0.9s. The velocity is 0.12m/s, which is equal to the chain speed when the seeder is running normally. Of the dynamic simulation of the movement and the actual situation is basically consistent with the apparent speed of the drive wheel has changed the acceleration and additional dynamic load, the chain drive has a very serious damage, and the maximum load value of 47.28N, in order to reduce the damage to the chain, As far as possible so that the sowing machine in the work to maintain a reasonable uniform speed, to avoid a greater acceleration, the corn sowing machine drive the design of a certain reference.

  17. Computational analysis of nonlinearities within dynamics of cable-based driving systems

    Science.gov (United States)

    Anghelache, G. D.; Nastac, S.

    2017-08-01

    This paper deals with computational nonlinear dynamics of mechanical systems containing some flexural parts within the actuating scheme, and, especially, the situations of the cable-based driving systems were treated. It was supposed both functional nonlinearities and the real characteristic of the power supply, in order to obtain a realistically computer simulation model being able to provide very feasible results regarding the system dynamics. It was taken into account the transitory and stable regimes during a regular exploitation cycle. The authors present a particular case of a lift system, supposed to be representatively for the objective of this study. The simulations were made based on the values of the essential parameters acquired from the experimental tests and/or the regular practice in the field. The results analysis and the final discussions reveal the correlated dynamic aspects within the mechanical parts, the driving system, and the power supply, whole of these supplying potential sources of particular resonances, within some transitory phases of the working cycle, and which can affect structural and functional dynamics. In addition, it was underlines the influences of computational hypotheses on the both quantitative and qualitative behaviour of the system. Obviously, the most significant consequence of this theoretical and computational research consist by developing an unitary and feasible model, useful to dignify the nonlinear dynamic effects into the systems with cable-based driving scheme, and hereby to help an optimization of the exploitation regime including a dynamics control measures.

  18. Study on dynamic behavior analysis of towed line array sensor

    Directory of Open Access Journals (Sweden)

    Hyun Kyoung Shin

    2012-03-01

    Full Text Available A set of equations of motion is derived for vibratory motions of an underwater cable connected to a moving vehicle at one end and with drogues at the other end. From the static analysis, cable configurations are obtained for different vehicle speeds and towing pretensions are determined by fluid resistance of drogues. Also the dynamic analysis is required to predict its vibratory motion. Nonlinear fluid drag forces greatly influence the dynamic tension. In this study, a numerical analysis program was developed to find out the characteristic of cable behaviour. The motion is described in terms of space and time coordinates based on Chebyshev polynomial expansions. For the spatial integration the collocation method is employed and the Newmark method is applied for the time integration. Dynamic tensions, displacements, velocities, accelerations were predicted in the time domain while natural frequencies and transfer functions were obtained in the frequency domain.

  19. High throughput gene expression measurement with real time PCR in a microfluidic dynamic array.

    Directory of Open Access Journals (Sweden)

    Sandra L Spurgeon

    Full Text Available We describe a high throughput gene expression platform based on microfluidic dynamic arrays. This system allows 2,304 simultaneous real time PCR gene expression measurements in a single chip, while requiring less pipetting than is required to set up a 96 well plate. We show that one can measure the expression of 45 different genes in 18 tissues with replicates in a single chip. The data have excellent concordance with conventional real time PCR and the microfluidic dynamic arrays show better reproducibility than commercial DNA microarrays.

  20. A dynamic zone estimation method using cumulative voxels for autonomous driving

    Directory of Open Access Journals (Sweden)

    Seongjo Lee

    2017-01-01

    Full Text Available Obstacle avoidance and available road identification technologies have been investigated for autonomous driving of an unmanned vehicle. In order to apply research results to autonomous driving in real environments, it is necessary to consider moving objects. This article proposes a preprocessing method to identify the dynamic zones where moving objects exist around an unmanned vehicle. This method accumulates three-dimensional points from a light detection and ranging sensor mounted on an unmanned vehicle in voxel space. Next, features are identified from the cumulative data at high speed, and zones with significant feature changes are estimated as zones where dynamic objects exist. The approach proposed in this article can identify dynamic zones even for a moving vehicle and processes data quickly using several features based on the geometry, height map and distribution of three-dimensional space data. The experiment for evaluating the performance of proposed approach was conducted using ground truth data on simulation and real environment data set.

  1. Energy Barriers and Driving Forces Associated with the Dynamic Transformation of Ti-6Al-4V (Preprint)

    Science.gov (United States)

    2017-12-11

    AFRL-RX-WP-JA-2017-0516 ENERGY BARRIERS AND DRIVING FORCES ASSOCIATED WITH THE DYNAMIC TRANSFORMATION OF TI-6AL-4V (PREPRINT) S.L...TYPE 3. DATES COVERED (From - To) 11 December 2017 Interim 19 March 2014 – 11 November 2017 4. TITLE AND SUBTITLE ENERGY BARRIERS AND DRIVING FORCES...The energy barriers and driving forces associated with dynamic transformation in Ti-6Al-4V are evaluated. It is shown that the stored energy is less

  2. Implementation of Multi-Body Dynamics Simulation for the Conveyor Chain Drive System

    Directory of Open Access Journals (Sweden)

    Suvanjumrat Chakrit

    2017-01-01

    Full Text Available The conveyor chain drive system which included four sprockets, four flat bars (chain guides and one conveyor chain had been assembled into commercial software, MSC.ADAMS. The conveyor chain was connected with rollers for running on the chain guides. The multi-body dynamics (MBD simulation was implemented to study the large displacement of chain components which happened during rotations of the symmetric model of the conveyor chain drive system. The physical experiment had obtained by construction of the conveyor chain drive system regarding the MBD model. The speeds of chain drive were adjusted by a gear motor with a converter. The trajectory of conveyor chain links which respectively meshed and ran on sprockets and chain guides was recorded by a high speed camera. Furthermore, impact-contact forces by a collision of components in the conveyor chain drive system during rotation were analysis. The comparison between MBD simulation and physical experiment of the conveyor chain drive system was performed for validation of simulation models. The MBD simulation results were in good agreement with the experimental data which obtained an average error of 3.95%.

  3. Dynamic focusing of phased arrays for nondestructive testing: characterization and application

    International Nuclear Information System (INIS)

    Lamarre, A.; Mainguy, F.

    1999-01-01

    Recent developments in Phased Array hardware developed by R/D TECH for nondestructive testing now allow dynamic focusing on reception. This new option, borrowed from medical technology, enables a programmable, real-time array response on reception by modifying the delay line, the gain, and the activation of each element as a function of time. This technology is presented as a new powerful tool, which can extend the depth-of-field, reduce the beam spread and increase the overall signal-to-noise ratio. Implementation of dynamic focusing in Phased Array systems will present many advantages such as an increase of the Pulse Rate Frequency (PRF). The technology implies a lot of significant possibilities, but also an extensive beam characterization. Some results are presented to quantify the advantages and drawbacks of the technique in comparison with standard phased array zone focusing and conventional UT. Results are clearly demonstrating the effect of dynamic focusing on the depth-of-field, the beam spread, the signal-to-noise ratio, and the acquisition rate, both with linear and annular arrays. Therefore this technique is suitable for applications where long soundpaths and small beam divergence are required as boresonic, billet, and blade root inspections. (author)

  4. Investigation of magnetization dynamics in 2D Ni80Fe20 diatomic nanodot arrays

    International Nuclear Information System (INIS)

    De, Anulekha; Mondal, Sucheta; Banerjee, Chandrima; Chaurasiya, Avinash K; Mandal, Ruma; Barman, Anjan; Otani, Yoshichika; Mitra, Rajib K

    2017-01-01

    Magnetization dynamics in Ni 80 Fe 20 (Py) diatomic nanodots (nanodots of the same thickness but with large and small diameters that are closely placed to each other so as to act as a diatomic basis structure) embedded in 2D arrays have been investigated by the Brillouin light scattering technique. A distinct variation of resonant mode characteristics for different in-plane bias magnetic field applied along two different orientations of the lattice has been observed. Micromagnetic simulations reproduced the observed dynamical behaviour and revealed the variation of spatial distribution of collective modes of constituent single nanodots with different diameter and a diatomic unit forming the large array to understand the evolution of the magnetization dynamics from a single dot to the large array via a diatomic unit. The changes in mode frequency, spatial profiles of the modes, and appearance of new modes in a diatomic unit and its array from that of the constituent single dots indicate the strong magnetostatic interaction among the dots within the diatomic unit. Also, the occurrence of the new interacting mode at different frequencies for different orientations of the bias field indicates the change in the nature of interaction among the dots within the diatomic unit with bias magnetic field. The mode profiles also show distinct behaviour for smooth and rough-edged dots. This work motivates the study of magnonic band structure formation of such a dipolarly coupled nanodot array containing a complex double-dot unit cell. (paper)

  5. A graphical interface based model for wind turbine drive train dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Manwell, J.F.; McGowan, J.G.; Abdulwahid, U.; Rogers, A. [Univ. of Massachusetts, Amherst, MA (United States); McNiff, B. [McNiff Light Industry, Blue Hill, ME (United States)

    1996-12-31

    This paper presents a summary of a wind turbine drive train dynamics code that has been under development at the University of Massachusetts, under National Renewable Energy Laboratory (NREL) support. The code is intended to be used to assist in the proper design and selection of drive train components. This work summarizes the development of the equations of motion for the model, and discusses the method of solution. In addition, a number of comparisons with analytical solutions and experimental field data are given. The summary includes conclusions and suggestions for future work on the model. 13 refs., 10 figs.

  6. Dynamic stability of forklift trucks in cornering situations: parametrical analysis using a driving simulator

    Science.gov (United States)

    Lemerle, P.; Höppner, O.; Rebelle, J.

    2011-10-01

    This paper describes the examination of the vehicle dynamics and stability of four-wheeled forklift trucks (FLTs) in cornering situations. Cornering at excessive speed is one major reason for fatal accidents with forklifts caused by lateral tipover. In order to increase the lateral stability of this kind of working machinery, the influence of certain important design properties has been studied using an appropriate vehicle simulation model and a driving simulator. The simulation model is based on a multi-body system approach and includes submodels for the propulsion system and the tyres. The driving behaviour of the operator has not been modelled. Instead, a driving simulator has been built up and a real human driver was employed for ensuring adequate and realistic model input. As there have not been any suitable standardised test manoeuvres available for FLTs, a new driving test has been developed to assess the lateral stability. This test resembles the well-known J turn/Fishhook turn, but includes a more dynamic counter-steering action. Furthermore, the dimensions of the test track are defined. Therefore, the test is better adapted to the driving dynamics of forklifts and reflects the real driver behaviour more closely. Finally, a parametrical study has been performed, examining the influence of certain important technical properties of the truck such as the maximum speed, the position of centre of gravity, rear axle design features and tyre properties. The results of this study may lead to a better understanding of the vehicle dynamics of forklifts and facilitate goal-oriented design improvements.

  7. Bacteria-foraging based-control of high-performance railway level-crossing safety drives fed from photovoltaic array

    Directory of Open Access Journals (Sweden)

    Essamudin A. Ebrahim

    2016-12-01

    Full Text Available In the past ten years, railway level-crossing accidents have noticeably escalated in an indisputably preposterous manner, this devastating snag opened the floodgates for the frustrating death of a numerous number of the third world’s citizens, especially in Egypt. To tackle with this problem, a fully intelligent control system is required, which must be automated without human intervention. So, in this research, a new proposed level-crossing tracking system is designed and introduced. The system comprises a high-performance induction motor (IM fed from photovoltaic (PV array, the boom barrier (gate with its mechanism – as a load – buck–boost converter, inverter, and two smart PI-controllers. The first one is designed to regulate the duty cycle of the converter to its optimum value required to balance between maximum power point tracking (MPPT and keeping dc-link voltage of the inverter at a minimum level needed to maintain the motor internal torque at rated value. The second PI-controller is designed for speed control of indirect field-oriented vector-control (IFO-VC IM. The proposed design problems of MPPT, dc-link voltage and speed controllers are solved as optimization problems by bacteria-foraging optimization (BFO algorithm to search for the optimal PI-parameters. The simulation test results are acquired when using the battery-less PV-array with and without the proposed controllers. Also, results are obtained when applying several prescribed speed trajectories to test the robustness against PV-irradiance fluctuations and motor-dynamic disturbances. From these results, the proposed intelligent controllers are robust compared to classical Ziegler–Nichols (ZN PI-controllers and also when the motor is directly fed from PV generator without converter.

  8. Abdominal and obstetric applications of a dynamically focused phased array real time ultrasound system.

    Science.gov (United States)

    Morgan, C L; Trought, W S; von Ramm, O T; Thurstone, F L

    1980-05-01

    Abdominal and obstetric applications of a dynamically focused phased array real time ultrasonic system are described. This work was performed utilising both the Thaumascan (two-dimensional, high resolution, actual time, ultrasound, multi-element array scanner) and the first commercial unit based on this system, the Grumman RT-400. Examples of normal and pathological anatomy are presented from over 300 examinations performed to date, including a series of 28 abdominal aortic aneurysms studied with the RT-400. Following electronic alterations in the Thaumascan with resultant improvement in the grey scale, prospective analyses in 86 obstetric and 23 abdominal examinations were undertaken. These studies indicate that fetal, intra-uterine, and abdominal structures can be rapidly and consistently imaged. The value of real time ultrasonic scanning in obstetric and abdominal examinations is illustrated. The principles of dynamically focused phased arrays are described, and the merits and limitations of these systems are discussed.

  9. Bit-systolic arithmetic arrays using dynamic differential gallium arsenide circuits

    Science.gov (United States)

    Beagles, Grant; Winters, Kel; Eldin, A. G.

    1992-01-01

    A new family of gallium arsenide circuits for fine grained bit-systolic arithmetic arrays is introduced. This scheme combines features of two recent techniques of dynamic gallium arsenide FET logic and differential dynamic single-clock CMOS logic. The resulting circuits are fast and compact, with tightly constrained series FET propagation paths, low fanout, no dc power dissipation, and depletion FET implementation without level shifting diodes.

  10. Dynamic Conformations of Nucleosome Arrays in Solution from Small-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Howell, Steven C. [George Washington Univ., Washington, DC (United States)

    2016-01-31

    We set out to determine quantitative information regarding the dynamic conformation of nucleosome arrays in solution using experimental SAXS. Toward this end, we developed a CG simulation algorithm for dsDNA which rapidly generates ensembles of structures through Metropolis MC sampling of a Markov chain.

  11. A DP based scheme for real-time reconfiguration of solar cell arrays exposed to dynamic changing inhomogeneous illuminations

    DEFF Research Database (Denmark)

    Shi, Liping; Brehm, Robert

    2016-01-01

    The overall energy conversion efficiency of solar cell arrays is highly effected by partial shading effects. Especially for solar panel arrays installed in environments which are exposed to inhomogeneous dynamic changing illuminations such as on roof tops of electrical vehicles the overall system...... efficiency is drastically reduced. Dynamic real-time reconfiguration of the solar panel array can reduce effects on the output efficiency due to partial shading. This results in a maximized power output of the panel array when exposed to dynamic changing illuminations. The optimal array configuration...... with respect to shading patterns can be stated as a combinatorial optimization problem and this paper proposes a dynamic programming (DP) based algorithm which finds the optimal feasible solution to reconfigure the solar panel array for maximum efficiency in real-time with linear time complexity. It is shown...

  12. Integration of silicon-based neural probes and micro-drive arrays for chronic recording of large populations of neurons in behaving animals.

    Science.gov (United States)

    Michon, Frédéric; Aarts, Arno; Holzhammer, Tobias; Ruther, Patrick; Borghs, Gustaaf; McNaughton, Bruce; Kloosterman, Fabian

    2016-08-01

    Understanding how neuronal assemblies underlie cognitive function is a fundamental question in system neuroscience. It poses the technical challenge to monitor the activity of populations of neurons, potentially widely separated, in relation to behaviour. In this paper, we present a new system which aims at simultaneously recording from a large population of neurons from multiple separated brain regions in freely behaving animals. The concept of the new device is to combine the benefits of two existing electrophysiological techniques, i.e. the flexibility and modularity of micro-drive arrays and the high sampling ability of electrode-dense silicon probes. Newly engineered long bendable silicon probes were integrated into a micro-drive array. The resulting device can carry up to 16 independently movable silicon probes, each carrying 16 recording sites. Populations of neurons were recorded simultaneously in multiple cortical and/or hippocampal sites in two freely behaving implanted rats. Current approaches to monitor neuronal activity either allow to flexibly record from multiple widely separated brain regions (micro-drive arrays) but with a limited sampling density or to provide denser sampling at the expense of a flexible placement in multiple brain regions (neural probes). By combining these two approaches and their benefits, we present an alternative solution for flexible and simultaneous recordings from widely distributed populations of neurons in freely behaving rats.

  13. Dynamic analysis and vibration testing of CFRP drive-line system used in heavy-duty machine tool

    Directory of Open Access Journals (Sweden)

    Mo Yang

    2018-03-01

    Full Text Available Low critical rotary speed and large vibration in the metal drive-line system of heavy-duty machine tool affect the machining precision seriously. Replacing metal drive-line with the CFRP drive-line can effectively solve this problem. Based on the composite laminated theory and the transfer matrix method (TMM, this paper puts forward a modified TMM to analyze dynamic characteristics of CFRP drive-line system. With this modified TMM, the CFRP drive-line of a heavy vertical miller is analyzed. And the finite element modal analysis model of the shafting is established. The results of the modified TMM and finite element analysis (FEA show that the modified TMM can effectively predict the critical rotary speed of CFRP drive-line. And the critical rotary speed of CFRP drive-line is 20% higher than that of the original metal drive-line. Then, the vibration of the CFRP and the metal drive-line were tested. The test results show that application of the CFRP drive shaft in the drive-line can effectively reduce the vibration of the heavy-duty machine tool. Keywords: CFRP drive-line system, Dynamic behavior, Transfer matrix, Vibration measurement

  14. Anthropogenic noise pollution from pile-driving disrupts the structure and dynamics of fish shoals.

    Science.gov (United States)

    Herbert-Read, James E; Kremer, Louise; Bruintjes, Rick; Radford, Andrew N; Ioannou, Christos C

    2017-09-27

    Noise produced from a variety of human activities can affect the physiology and behaviour of individual animals, but whether noise disrupts the social behaviour of animals is largely unknown. Animal groups such as flocks of birds or shoals of fish use simple interaction rules to coordinate their movements with near neighbours. In turn, this coordination allows individuals to gain the benefits of group living such as reduced predation risk and social information exchange. Noise could change how individuals interact in groups if noise is perceived as a threat, or if it masked, distracted or stressed individuals, and this could have impacts on the benefits of grouping. Here, we recorded trajectories of individual juvenile seabass ( Dicentrarchus labrax ) in groups under controlled laboratory conditions. Groups were exposed to playbacks of either ambient background sound recorded in their natural habitat, or playbacks of pile-driving, commonly used in marine construction. The pile-driving playback affected the structure and dynamics of the fish shoals significantly more than the ambient-sound playback. Compared to the ambient-sound playback, groups experiencing the pile-driving playback became less cohesive, less directionally ordered, and were less correlated in speed and directional changes. In effect, the additional-noise treatment disrupted the abilities of individuals to coordinate their movements with one another. Our work highlights the potential for noise pollution from pile-driving to disrupt the collective dynamics of fish shoals, which could have implications for the functional benefits of a group's collective behaviour. © 2017 The Authors.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  16. Dynamical transitions in a modulated Landau-Zener model with finite driving fields

    Science.gov (United States)

    Li, Wei; Cen, Li-Xiang

    2018-02-01

    We investigate a special time-dependent quantum model which assumes the Landau-Zener driving form but with an overall modulation of the intensity of the pulsing field. We demonstrate that the dynamics of the system, including the two-level case as well as its multi-level extension, is exactly solvable analytically. Differing from the original Landau-Zener model, the nonadiabatic effect of the evolution in the present driving process does not destroy the desired population transfer. As the sweep protocol employs only the finite driving fields which tend to zero asymptotically, the cutoff error due to the truncation of the driving pulse to the finite time interval turns out to be negligibly small. Furthermore, we investigate the noise effect on the driving protocol due to the dissipation of the surrounding environment. The losses of the fidelity in the protocol caused by both the phase damping process and the random spin flip noise are estimated by solving numerically the corresponding master equations within the Markovian regime.

  17. Determination of fault operation dynamical constraints for the design of wind turbine DFIG drives

    CERN Document Server

    Aguglia, Davide; Wamkeue, René; Cros, Jérôme

    2010-01-01

    This paper presents an efficient design tool for the estimation of the transient electromagnetic peak torque and transient rotor over-voltages of wind turbines (WT) doubly-fed induction generators (DFIG) during severe fault conditions on the grid side. This versatile and robust tool is well adapted to the implementation in a DFIG drives CAD environment using iterative optimization procedures. In such an application, it is used to compute the dynamical constraints function during the integrated design process of the whole drive including the generator, the gearbox and the power converters. Results show that it is necessary to take into account the dynamical constraints under fault operation, during the early steps of the system design process. Another application of the tool is also illustrated in the paper: the design of the protection system (i.e. the crowbar resistance) for a given generator, a given gearbox and a given power converter.

  18. Kinematic and dynamic modeling and approximate analysis of a roller chain drive

    DEFF Research Database (Denmark)

    Fuglede, Niels; Thomsen, Jon Juel

    2016-01-01

    for analytical studies of the coupled motion of the chain spans and driven sprocket. Parametric excitation of the spans come from sprocket angular displacements, and the driven sprocket acts as a boundary which can be compliant in the axial direction. External transverse excitation of the spans comes from...... and coupled motion. Together, the kinematic and dynamic model are aimed toward providing a framework for conducting and understanding both numerical, and experimental investigations of roller chain drive dynamics.......A simple roller chain drive consisting of two sprockets connected by tight chain spans is investigated. First, a kinematic model is presented which include both spans and sprockets. An approach for calculating the chain wrapping length is presented, which also allows for the exact calculation...

  19. Dynamic neural networks based on-line identification and control of high performance motor drives

    Science.gov (United States)

    Rubaai, Ahmed; Kotaru, Raj

    1995-01-01

    In the automated and high-tech industries of the future, there wil be a need for high performance motor drives both in the low-power range and in the high-power range. To meet very straight demands of tracking and regulation in the two quadrants of operation, advanced control technologies are of a considerable interest and need to be developed. In response a dynamics learning control architecture is developed with simultaneous on-line identification and control. the feature of the proposed approach, to efficiently combine the dual task of system identification (learning) and adaptive control of nonlinear motor drives into a single operation is presented. This approach, therefore, not only adapts to uncertainties of the dynamic parameters of the motor drives but also learns about their inherent nonlinearities. In fact, most of the neural networks based adaptive control approaches in use have an identification phase entirely separate from the control phase. Because these approaches separate the identification and control modes, it is not possible to cope with dynamic changes in a controlled process. Extensive simulation studies have been conducted and good performance was observed. The robustness characteristics of neuro-controllers to perform efficiently in a noisy environment is also demonstrated. With this initial success, the principal investigator believes that the proposed approach with the suggested neural structure can be used successfully for the control of high performance motor drives. Two identification and control topologies based on the model reference adaptive control technique are used in this present analysis. No prior knowledge of load dynamics is assumed in either topology while the second topology also assumes no knowledge of the motor parameters.

  20. Dynamic Tuning of Plasmon-Exciton Coupling in Arrays of Nanodisk-J-aggregate Complexes

    KAUST Repository

    Zheng, Yue Bing

    2010-07-21

    Figure Presented Dynamic tuning of plasmon-exclton resonant coupling in arrays of nanodisk-J-aggregate complexes is demonstrated. The angle-resolved spectra of an array of bare gold nanodisks exhibit continuous shifting of localized surface plasmon resonance. This characteristic enables the production of real-time, controllable spectral overlap between molecular resonance and plasmóme resonance. The resonant interaction strength as a function of spectral overlap is explored and the coupling strength changes with the incident angle of a probe light, in accord with simulations based on coupled dipóle approximation method. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Simulation and Implementation of Sensorless Control in Multi-Motors Electric Drives with High Dynamics

    Directory of Open Access Journals (Sweden)

    Marcel Nicola

    2017-05-01

    Full Text Available In this article we’ll tackle the control of multi-motors electric drives with high dynamic, with rapid changes in torque and speed, with rigid or flexible coupling of motors, where the control strategy is FOC (Field Oriented Control for each drives and the distributed control in local network using the CANopen protocol. In the surface mining industry, from which the electric drive application for this article is selected, the general trend is toward using asynchronous motors with short-circuit rotor, due to the advantages of this motor both in terms of design and operation. In order to achieve the variable speed, must be used the static frequency converters with sensorless control, where speed is estimated using a Model References Adaptive Control Estimator. The global control system proposed in this paper contain this type of MRAC estimator together with PI-control based, who ensures a good dynamic performance but in a lower complexity of structure such that are properly to implement in real time in a distributed control system with DSP in local network using the CANopen protocol with advantages in terms of software technology, as well as control cost and flexibility of use. Following these directions a functional application was implemented and tested in practice.

  2. Spatial and temporal EEG dynamics of dual-task driving performance

    Directory of Open Access Journals (Sweden)

    Chen Shi-An

    2011-02-01

    Full Text Available Abstract Background Driver distraction is a significant cause of traffic accidents. The aim of this study is to investigate Electroencephalography (EEG dynamics in relation to distraction during driving. To study human cognition under a specific driving task, simulated real driving using virtual reality (VR-based simulation and designed dual-task events are built, which include unexpected car deviations and mathematics questions. Methods We designed five cases with different stimulus onset asynchrony (SOA to investigate the distraction effects between the deviations and equations. The EEG channel signals are first converted into separated brain sources by independent component analysis (ICA. Then, event-related spectral perturbation (ERSP changes of the EEG power spectrum are used to evaluate brain dynamics in time-frequency domains. Results Power increases in the theta and beta bands are observed in relation with distraction effects in the frontal cortex. In the motor area, alpha and beta power suppressions are also observed. All of the above results are consistently observed across 15 subjects. Additionally, further analysis demonstrates that response time and multiple cortical EEG power both changed significantly with different SOA. Conclusions This study suggests that theta power increases in the frontal area is related to driver distraction and represents the strength of distraction in real-life situations.

  3. Inhomogeneous quasi-adiabatic driving of quantum critical dynamics in weakly disordered spin chains

    International Nuclear Information System (INIS)

    Rams, Marek M; Mohseni, Masoud; Campo, Adolfo del

    2016-01-01

    We introduce an inhomogeneous protocol to drive a weakly disordered quantum spin chain quasi-adiabatically across a quantum phase transition and minimize the residual energy of the final state. The number of spins that simultaneously reach the critical point is controlled by the length scale in which the magnetic field is modulated, introducing an effective size that favors adiabatic dynamics. The dependence of the residual energy on this length scale and the velocity at which the magnetic field sweeps out the chain is shown to be nonmonotonic. We determine the conditions for an optimal suppression of the residual energy of the final state and show that inhomogeneous driving can outperform conventional adiabatic schemes based on homogeneous control fields by several orders of magnitude. (paper)

  4. Dynamic characteristics of the national full-scale aerodynamic complex drive fan blades

    Science.gov (United States)

    Peterson, Randall L.; Graham, Todd; Lau, Benton

    1987-01-01

    An extensive experimental test program was conducted to define the dynamic characteristics of the newly installed fan blades of the NASA Ames 40- by 80-/80- by 120-Foot Wind Tunnel. The tests were intended to substantiate the blade design and manufacturing process, verify installation integrity, and guarantee safe fan-drive operation. The program included a shake test of each fan blade after installation and before operation as well as the monitoring of blade strain levels during initial operation. Structural characteristics, as determined by the shake test, include the modal frequency and damping values for elastic bending and torsion modes between 5 and 130 Hz. Operational testing defined the maximum and oscillatory blade-bending strains throughout the drive-system operational envelope. Results are presented for the shake test and initial operation of the 40- by 80-Foot Wind Tunnel circuit.

  5. Dynamic analysis and vibration testing of CFRP drive-line system used in heavy-duty machine tool

    Science.gov (United States)

    Yang, Mo; Gui, Lin; Hu, Yefa; Ding, Guoping; Song, Chunsheng

    2018-03-01

    Low critical rotary speed and large vibration in the metal drive-line system of heavy-duty machine tool affect the machining precision seriously. Replacing metal drive-line with the CFRP drive-line can effectively solve this problem. Based on the composite laminated theory and the transfer matrix method (TMM), this paper puts forward a modified TMM to analyze dynamic characteristics of CFRP drive-line system. With this modified TMM, the CFRP drive-line of a heavy vertical miller is analyzed. And the finite element modal analysis model of the shafting is established. The results of the modified TMM and finite element analysis (FEA) show that the modified TMM can effectively predict the critical rotary speed of CFRP drive-line. And the critical rotary speed of CFRP drive-line is 20% higher than that of the original metal drive-line. Then, the vibration of the CFRP and the metal drive-line were tested. The test results show that application of the CFRP drive shaft in the drive-line can effectively reduce the vibration of the heavy-duty machine tool.

  6. Steady-state responses of a belt-drive dynamical system under dual excitations

    Science.gov (United States)

    Ding, Hu

    2016-02-01

    The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excited by the firing pulsations of the engine and the harmonic motion of the foundation. Nonlinear discrete-continuous equations are derived for coupling the transverse vibration of the belt spans and the rotations of the driving and driven pulleys and the accessory pulley. The nonlinear dynamics is studied under equal and multiple relations between the frequency of the firing pulsations and the frequency of the foundation motion. Furthermore, translating belt spans are modeled as axially moving strings. A set of nonlinear piecewise ordinary differential equations is achieved by using the Galerkin truncation. Under various relations between the excitation frequencies, the time histories of the dynamical system are numerically simulated based on the time discretization method. Furthermore, the stable steady-state periodic response curves are calculated based on the frequency sweep. Moreover, the convergence of the Galerkin truncation is examined. Numerical results demonstrate that the one-way clutch reduces the resonance amplitude of the rotations of the driven pulley and the accessory pulley. On the other hand, numerical examples prove that the resonance areas of the belt spans are decreased by eliminating the torque-transmitting in the opposite direction. With the increasing amplitude of the foundation excitation, the damping effect of the one-way clutch will be reduced. Furthermore, as the amplitude of the firing pulsations of the engine increases, the jumping phenomena in steady-state response curves of the belt-drive system with or without a one-way clutch both occur.

  7. Nonlinear Dynamics Response of a Planar Mechanism with Two Driving Links and Prismatic Pair Clearance

    Directory of Open Access Journals (Sweden)

    Lijuan Wu

    2017-01-01

    Full Text Available The influence of the joint clearance on the dynamic response of a planar mechanism with two driving links and prismatic pair clearance is investigated under variable input speeds of the system. The simulation model was built with a nonlinear impact model. The normal contact force is characterized by Hertz contact theory and an energy dissipation term. A tangential friction force is involved in the simulation model based on Coulomb’s friction law. The simulation results indicate that the largest Lyapunov exponents are dependent on the clearance size and the input speed.

  8. Short-term mudflat dynamics drive long-term cyclic salt marsh dynamics

    NARCIS (Netherlands)

    Bouma, T.; van Belzen, J; Balke, T; van Dalen, J.H.; Klaassen, P.; Hartog, A. M.; Callaghan, D.P.; Hu, Z.; Stive, M.J.F.; Temmerman, S.; Herman, P.M.J.

    2016-01-01

    Our study aims to enhance process understanding of the long-term (decadal and longer) cyclic marsh dynamics by identifying the mechanisms that translate large-scale physical forcing in the system into vegetation change, in particular (i) the initiation of lateral erosion on an expanding marsh,

  9. Short-term mudflat dynamics drive long-term cyclic salt marsh dynamics

    NARCIS (Netherlands)

    Bouma, T.J.; van Belzen, J.; Balke, T.; van Dalen, J.; KLaassen, P.; Hartog, A.M.; Callaghan, D.P.; Hu, Z.; Stive, M.J.F.; Temmerman, S.; Herman, P.M.J.

    2016-01-01

    Our study aims to enhance process understanding of the long-term (decadal and longer) cyclic marsh dynamics by identifying the mechanisms that translate large-scale physical forcing in the system into vegetation change, in particular (i) the initiation of lateral erosion on an expanding

  10. Intrinsic spin dynamics in optically excited nanoscale magnetic tunnel junction arrays restored by dielectric coating

    Science.gov (United States)

    Jaris, M.; Yahagi, Y.; Mahato, B. K.; Dhuey, S.; Cabrini, S.; Nikitin, V.; Stout, J.; Hawkins, A. R.; Schmidt, H.

    2016-11-01

    We report the all-optical observation of intrinsic spin dynamics and extraction of magnetic material parameters from arrays of sub-100 nm spin-transfer torque magnetic random access memory (STT-MRAM) devices with a CoFeB/MgO interface. To this end, the interference of surface acoustic waves with time-resolved magneto-optic signals via magneto-elastic coupling was suppressed using a dielectric coating. The efficacy of this method is demonstrated experimentally and via modeling on a nickel nanomagnet array. The magnetization dynamics for both coated nickel and STT-MRAM arrays shows a restored field-dependent Kittel mode from which the effective damping can be extracted. We observe an increased low-field damping due to extrinsic contributions from magnetic inhomogeneities and variations in the nanomagnet shape, while the intrinsic Gilbert damping remains unaffected by patterning. The data are in excellent agreement with a local resonance model and have direct implications for the design of STT-MRAM devices as well as other nanoscale spintronic technologies.

  11. Controlled Nucleation and Growth of DNA Tile Arrays within Prescribed DNA Origami Frames and Their Dynamics

    Science.gov (United States)

    2015-01-01

    Controlled nucleation of nanoscale building blocks by geometrically defined seeds implanted in DNA nanoscaffolds represents a unique strategy to study and understand the dynamic processes of molecular self-assembly. Here we utilize a two-dimensional DNA origami frame with a hollow interior and selectively positioned DNA hybridization seeds to control the self-assembly of DNA tile building blocks, where the small DNA tiles are directed to fill the interior of the frame through prescribed sticky end interactions. This design facilitates the construction of DNA origami/array hybrids that adopt the overall shape and dimensions of the origami frame, forming a 2D array in the core consisting of a large number of simple repeating DNA tiles. The formation of the origami/array hybrid was characterized with atomic force microscopy, and the nucleation dynamics were monitored by serial AFM scanning and fluorescence spectroscopy, which revealed faster kinetics of growth within the frame as compared to growth without the presence of a frame. Our study provides insight into the fundamental behavior of DNA-based self-assembling systems. PMID:24575893

  12. Dynamic wedge, electron energy and beam profile Q.A. using an ionization chamber linear array

    International Nuclear Information System (INIS)

    Kenny, M.B.; Todd, S.P.

    1996-01-01

    Since the introduction of multi-modal linacs the quality assurance workload of a Physical Sciences department has increased dramatically. The advent of dynamic wedges has further complicated matters because of the need to invent accurate methods to perform Q.A. in a reasonable time. We have been using an ionization chamber linear array, the Thebes 7000 TM by Victoreen, Inc., for some years to measure X-ray and electron beam profiles. Two years ago we developed software to perform Q.A. on our dynamic wedges using the array and more recently included a routine to check electron beam energies using the method described by Rosenow, U.F. et al., Med. Phys. 18(1) 19-25. The integrated beam and profile management system has enabled us to maintain a comprehensive quality assurance programme on all our linaccs. Both our efficiency and accuracy have increased to the point where we are able to keep up with the greater number of tests required without an increase in staff or hours spent in quality assurance. In changing the processor from the Z80 of the Thebes console to the 486 of the PC we have also noticed a marked increase in the calibration stability of the array. (author)

  13. Opposing microtubule motors drive robust nuclear dynamics in developing muscle cells.

    Science.gov (United States)

    Wilson, Meredith H; Holzbaur, Erika L F

    2012-09-01

    Dynamic interactions with the cytoskeleton drive the movement and positioning of nuclei in many cell types. During muscle cell development, myoblasts fuse to form syncytial myofibers with nuclei positioned regularly along the length of the cell. Nuclear translocation in developing myotubes requires microtubules, but the mechanisms involved have not been elucidated. We find that as nuclei actively translocate through the cell, they rotate in three dimensions. The nuclear envelope, nucleoli and chromocenters within the nucleus rotate together as a unit. Both translocation and rotation require an intact microtubule cytoskeleton, which forms a dynamic bipolar network around nuclei. The plus- and minus-end-directed microtubule motor proteins, kinesin-1 and dynein, localize to the nuclear envelope in myotubes. Kinesin-1 localization is mediated at least in part by interaction with klarsicht/ANC-1/Syne homology (KASH) proteins. Depletion of kinesin-1 abolishes nuclear rotation and significantly inhibits nuclear translocation, resulting in the abnormal aggregation of nuclei at the midline of the myotube. Dynein depletion also inhibits nuclear dynamics, but to a lesser extent, leading to altered spacing between adjacent nuclei. Thus, oppositely directed motors acting from the surface of the nucleus drive nuclear motility in myotubes. The variable dynamics observed for individual nuclei within a single myotube are likely to result from the stochastic activity of competing motors interacting with a complex bipolar microtubule cytoskeleton that is also continuously remodeled as the nuclei move. The three-dimensional rotation of myotube nuclei may facilitate their motility through the complex and crowded cellular environment of the developing muscle cell, allowing for proper myonuclear positioning.

  14. Dynamic path planning for autonomous driving on various roads with avoidance of static and moving obstacles

    Science.gov (United States)

    Hu, Xuemin; Chen, Long; Tang, Bo; Cao, Dongpu; He, Haibo

    2018-02-01

    This paper presents a real-time dynamic path planning method for autonomous driving that avoids both static and moving obstacles. The proposed path planning method determines not only an optimal path, but also the appropriate acceleration and speed for a vehicle. In this method, we first construct a center line from a set of predefined waypoints, which are usually obtained from a lane-level map. A series of path candidates are generated by the arc length and offset to the center line in the s - ρ coordinate system. Then, all of these candidates are converted into Cartesian coordinates. The optimal path is selected considering the total cost of static safety, comfortability, and dynamic safety; meanwhile, the appropriate acceleration and speed for the optimal path are also identified. Various types of roads, including single-lane roads and multi-lane roads with static and moving obstacles, are designed to test the proposed method. The simulation results demonstrate the effectiveness of the proposed method, and indicate its wide practical application to autonomous driving.

  15. Charge solitons and their dynamical mass in one-dimensional arrays of Josephson junctions

    International Nuclear Information System (INIS)

    Homfeld, Jens; Protopopov, Ivan; Rachel, Stephan; Shnirman, Alexander

    2011-01-01

    We investigate charge transport in one-dimensional arrays of Josephson junctions. In the interesting regime of ''small charge solitons'' (polarons), ΛE J >E C >E J , where Λ is the (electrostatic) screening length, the charge dynamics are strongly influenced by the polaronic effects (i.e., by dressing of a Cooper pair by charge dipoles). In particular, the soliton's mass in this regime scales approximately as E J -2 . We employ two theoretical techniques: the many-body tight-binding approach and the mean-field approach, and the results of the two approaches agree in the regime of ''small charge solitons.'' Renormalization of the soliton's mass could be observed; for example, as enhancement of the persistent current in a ring-shaped array.

  16. Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives.

    Science.gov (United States)

    Kumar, Navneet; Raj Chelliah, Thanga; Srivastava, S P

    2015-07-01

    Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor dynamic performance of the drive. This study investigates the opportunity for improving dynamic performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The dynamic performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor dynamics improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Flexible Piezoelectric Tactile Sensor Array for Dynamic Three-Axis Force Measurement.

    Science.gov (United States)

    Yu, Ping; Liu, Weiting; Gu, Chunxin; Cheng, Xiaoying; Fu, Xin

    2016-06-03

    A new flexible piezoelectric tactile sensor array based on polyvinylidene fluoride (PVDF) film is proposed for measuring three-axis dynamic contact force distribution. The array consists of six tactile units arranged as a 3 × 2 matrix with spacing 8 mm between neighbor units. In each unit, a PVDF film is sandwiched between four square-shaped upper electrodes and one square-shaped lower electrode, forming four piezoelectric capacitors. A truncated pyramid bump is located above the four piezoelectric capacitors to improve force transmission. A three-axis contact force transmitted from the top of the bump will lead to the four piezoelectric capacitors underneath undergoing different charge changes, from which the normal and shear components of the force can be calculated. A series of dynamic tests have been carried out by exerting sinusoidal forces with amplitudes ranging from 0 to 0.5 N in the x-axis, 0 to 0.5 N in the y-axis, and 0 to 1.5 N in the z-axis, separately. The tactile units show good sensitivities with 14.93, 14.92, and 6.62 pC/N in the x-, y-, and z-axes, respectively. They can work with good linearity, relatively low coupling effect, high repeatability, and acceptable frequency response in the range of 5-400 Hz to both normal and shear load. In addition, dynamic three-axis force measurement has been conducted for all of the tactile units. The average errors between the applied and calculated forces are 10.68% ± 6.84%. Furthermore, the sensor array can be easily integrated onto a curved surface, such as robotic and prosthetic hands, due to its excellent flexibility.

  18. Flexible Piezoelectric Tactile Sensor Array for Dynamic Three-Axis Force Measurement

    Directory of Open Access Journals (Sweden)

    Ping Yu

    2016-06-01

    Full Text Available A new flexible piezoelectric tactile sensor array based on polyvinylidene fluoride (PVDF film is proposed for measuring three-axis dynamic contact force distribution. The array consists of six tactile units arranged as a 3 × 2 matrix with spacing 8 mm between neighbor units. In each unit, a PVDF film is sandwiched between four square-shaped upper electrodes and one square-shaped lower electrode, forming four piezoelectric capacitors. A truncated pyramid bump is located above the four piezoelectric capacitors to improve force transmission. A three-axis contact force transmitted from the top of the bump will lead to the four piezoelectric capacitors underneath undergoing different charge changes, from which the normal and shear components of the force can be calculated. A series of dynamic tests have been carried out by exerting sinusoidal forces with amplitudes ranging from 0 to 0.5 N in the x-axis, 0 to 0.5 N in the y-axis, and 0 to 1.5 N in the z-axis, separately. The tactile units show good sensitivities with 14.93, 14.92, and 6.62 pC/N in the x-, y-, and z-axes, respectively. They can work with good linearity, relatively low coupling effect, high repeatability, and acceptable frequency response in the range of 5–400 Hz to both normal and shear load. In addition, dynamic three-axis force measurement has been conducted for all of the tactile units. The average errors between the applied and calculated forces are 10.68% ± 6.84%. Furthermore, the sensor array can be easily integrated onto a curved surface, such as robotic and prosthetic hands, due to its excellent flexibility.

  19. Observing the dynamics of supermassive black hole binaries with pulsar timing arrays.

    Science.gov (United States)

    Mingarelli, C M F; Grover, K; Sidery, T; Smith, R J E; Vecchio, A

    2012-08-24

    Pulsar timing arrays are a prime tool to study unexplored astrophysical regimes with gravitational waves. Here, we show that the detection of gravitational radiation from individually resolvable supermassive black hole binary systems can yield direct information about the masses and spins of the black holes, provided that the gravitational-wave-induced timing fluctuations both at the pulsar and at Earth are detected. This in turn provides a map of the nonlinear dynamics of the gravitational field and a new avenue to tackle open problems in astrophysics connected to the formation and evolution of supermassive black holes. We discuss the potential, the challenges, and the limitations of these observations.

  20. Dynamic simulation of a fuel cell hybrid vehicle during the federal test procedure-75 driving cycle

    International Nuclear Information System (INIS)

    Kang, Sanggyu; Min, Kyoungdoug

    2016-01-01

    Highlights: • Development of a FCHV dynamic model. • Integration of a PEMFC system dynamic model with the electric vehicle model. • Investigation of the dynamic behavior of the FCEV and PEMFC system during FTP-75. • Capturing the dynamic correlation among components in PEMFC system during FTP-75. - Abstract: The dynamic behavior of a proton exchange membrane fuel cell (PEMFC) system is a crucial factor to ensure the safe and effective operation of fuel cell hybrid vehicles (FCHVs). Specifically, water and thermal management are critical to stabilize the performance of the PEMFC during severe load changes. In the present study, the FCHV dynamic model is developed. The dynamic model of the PEMFC system developed by Matlab–Simulink® is integrated into the electric vehicle model embedded in the Amesim®. The dynamic model of the PEMFC system is composed of a PEMFC stack, an air feeding system, and a thermal management system (TMS). The component models of PEMFC, a shell-and-tube gas-to-gas membrane humidifier, and a heat exchanger are validated via a comparison with the experimental data. The FCHV model is simulated during a federal test procedure (FTP)-75 driving cycle. One system configuration and control strategy is adopted to attain optimal water and thermal management in the PEMFC system. The vehicle speed obtained from the FCHV model aptly tracks the target velocity profile of the FTP-75 cycle within an error of ±0.5%. The dynamic behavior and correlation of each component in the PEMFC system is investigated. The mass and heat transfer in the PEMFC, a humidifier, and a heat exchanger are resolved to determine the species concentration and the temperature more accurately with discretization in the flow’s perpendicular direction. Discretization in the flow parallel direction of humidifier and heat exchanger model makes it possible to capture the distribution of the characteristics. The present model can be used to attain the optimization of the system

  1. Dynamics of macroscopic quantum self-bound states in arrays of transmon qubits

    Science.gov (United States)

    de Grandi, Claudia; Girvin, Steven M.

    2014-03-01

    We consider the many-body physics of an array of transmon qubits in a cavity. Due to the negative anharmonicity and the exchange coupling between the qubits, such a system realizes a Bose-Hubbard model with attractive interactions and thus the N-excitation manifold is expected to have self-bound states. We study the existence of such macroscopic states in the one-dimensional case with open boundary conditions as a function of the parameters of the model, comparing the classical and the quantum predictions. We then analyze the dynamics of the self-bound states in the experimentally relevant scenario of an open dissipative system, where the qubits have a finite energy relaxation time T1. We numerically simulate the dynamics with a quantum trajectory approach supported by a Lanczos diagonalization procedure.

  2. Driving self-assembly and emergent dynamics in colloidal suspensions by time-dependent magnetic fields

    Science.gov (United States)

    Martin, James E.; Snezhko, Alexey

    2013-12-01

    In this review we discuss recent research on driving self-assembly of magnetic particle suspensions subjected to alternating magnetic fields. The variety of structures and effects that can be induced in such systems is remarkably broad due to the large number of variables involved. The alternating field can be uniaxial, biaxial or triaxial, the particles can be spherical or anisometric, and the suspension can be dispersed throughout a volume or confined to a soft interface. In the simplest case the field drives the static or quasistatic assembly of unusual particle structures, such as sheets, networks and open-cell foams. More complex, emergent collective behaviors evolve in systems that can follow the time-dependent field vector. In these cases energy is continuously injected into the system and striking flow patterns and structures can arise. In fluid volumes these include the formation of advection and vortex lattices. At air-liquid and liquid-liquid interfaces striking dynamic particle assemblies emerge due to the particle-mediated coupling of the applied field to surface excitations. These out-of-equilibrium interface assemblies exhibit a number of remarkable phenomena, including self-propulsion and surface mixing. In addition to discussing various methods of driven self-assembly in magnetic suspensions, some of the remarkable properties of these novel materials are described.

  3. Electric drives

    CERN Document Server

    Boldea, Ion

    2005-01-01

    ENERGY CONVERSION IN ELECTRIC DRIVESElectric Drives: A DefinitionApplication Range of Electric DrivesEnergy Savings Pay Off RapidlyGlobal Energy Savings Through PEC DrivesMotor/Mechanical Load MatchMotion/Time Profile MatchLoad Dynamics and StabilityMultiquadrant OperationPerformance IndexesProblemsELECTRIC MOTORS FOR DRIVESElectric Drives: A Typical ConfigurationElectric Motors for DrivesDC Brush MotorsConventional AC MotorsPower Electronic Converter Dependent MotorsEnergy Conversion in Electric Motors/GeneratorsPOWER ELECTRONIC CONVERTERS (PECs) FOR DRIVESPower Electronic Switches (PESs)The

  4. Roles of dynamical symmetry breaking in driving oblate-prolate transitions of atomic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Oka, Yurie, E-mail: ok-yu@fuji.waseda.jp; Yanao, Tomohiro, E-mail: yanao@waseda.jp [Department of Applied Mechanics and Aerospace Engineering, Waseda University, Tokyo 169-8555 (Japan); Koon, Wang Sang, E-mail: koon@cds.caltech.edu [Control and Dynamical Systems, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-04-07

    This paper explores the driving mechanisms for structural transitions of atomic clusters between oblate and prolate isomers. We employ the hyperspherical coordinates to investigate structural dynamics of a seven-atom cluster at a coarse-grained level in terms of the dynamics of three gyration radii and three principal axes, which characterize overall mass distributions of the cluster. Dynamics of gyration radii is governed by two kinds of forces. One is the potential force originating from the interactions between atoms. The other is the dynamical forces called the internal centrifugal forces, which originate from twisting and shearing motions of the system. The internal centrifugal force arising from twisting motions has an effect of breaking the symmetry between two gyration radii. As a result, in an oblate isomer, activation of the internal centrifugal force that has the effect of breaking the symmetry between the two largest gyration radii is crucial in triggering structural transitions into prolate isomers. In a prolate isomer, on the other hand, activation of the internal centrifugal force that has the effect of breaking the symmetry between the two smallest gyration radii is crucial in triggering structural transitions into oblate isomers. Activation of a twisting motion that switches the movement patterns of three principal axes is also important for the onset of structural transitions between oblate and prolate isomers. Based on these trigger mechanisms, we finally show that selective activations of specific gyration radii and twisting motions, depending on the isomer of the cluster, can effectively induce structural transitions of the cluster. The results presented here could provide further insights into the control of molecular reactions.

  5. Roles of dynamical symmetry breaking in driving oblate-prolate transitions of atomic clusters

    Science.gov (United States)

    Oka, Yurie; Yanao, Tomohiro; Koon, Wang Sang

    2015-04-01

    This paper explores the driving mechanisms for structural transitions of atomic clusters between oblate and prolate isomers. We employ the hyperspherical coordinates to investigate structural dynamics of a seven-atom cluster at a coarse-grained level in terms of the dynamics of three gyration radii and three principal axes, which characterize overall mass distributions of the cluster. Dynamics of gyration radii is governed by two kinds of forces. One is the potential force originating from the interactions between atoms. The other is the dynamical forces called the internal centrifugal forces, which originate from twisting and shearing motions of the system. The internal centrifugal force arising from twisting motions has an effect of breaking the symmetry between two gyration radii. As a result, in an oblate isomer, activation of the internal centrifugal force that has the effect of breaking the symmetry between the two largest gyration radii is crucial in triggering structural transitions into prolate isomers. In a prolate isomer, on the other hand, activation of the internal centrifugal force that has the effect of breaking the symmetry between the two smallest gyration radii is crucial in triggering structural transitions into oblate isomers. Activation of a twisting motion that switches the movement patterns of three principal axes is also important for the onset of structural transitions between oblate and prolate isomers. Based on these trigger mechanisms, we finally show that selective activations of specific gyration radii and twisting motions, depending on the isomer of the cluster, can effectively induce structural transitions of the cluster. The results presented here could provide further insights into the control of molecular reactions.

  6. Roles of dynamical symmetry breaking in driving oblate-prolate transitions of atomic clusters

    International Nuclear Information System (INIS)

    Oka, Yurie; Yanao, Tomohiro; Koon, Wang Sang

    2015-01-01

    This paper explores the driving mechanisms for structural transitions of atomic clusters between oblate and prolate isomers. We employ the hyperspherical coordinates to investigate structural dynamics of a seven-atom cluster at a coarse-grained level in terms of the dynamics of three gyration radii and three principal axes, which characterize overall mass distributions of the cluster. Dynamics of gyration radii is governed by two kinds of forces. One is the potential force originating from the interactions between atoms. The other is the dynamical forces called the internal centrifugal forces, which originate from twisting and shearing motions of the system. The internal centrifugal force arising from twisting motions has an effect of breaking the symmetry between two gyration radii. As a result, in an oblate isomer, activation of the internal centrifugal force that has the effect of breaking the symmetry between the two largest gyration radii is crucial in triggering structural transitions into prolate isomers. In a prolate isomer, on the other hand, activation of the internal centrifugal force that has the effect of breaking the symmetry between the two smallest gyration radii is crucial in triggering structural transitions into oblate isomers. Activation of a twisting motion that switches the movement patterns of three principal axes is also important for the onset of structural transitions between oblate and prolate isomers. Based on these trigger mechanisms, we finally show that selective activations of specific gyration radii and twisting motions, depending on the isomer of the cluster, can effectively induce structural transitions of the cluster. The results presented here could provide further insights into the control of molecular reactions

  7. Kibble-Zurek dynamics in an array of coupled binary Bose condensates

    Science.gov (United States)

    Xu, Jun; Wu, Shuyuan; Qin, Xizhou; Huang, Jiahao; Ke, Yongguan; Zhong, Honghua; Lee, Chaohong

    2016-03-01

    Universal dynamics of spontaneous symmetry breaking is central to understanding the universal behavior of spontaneous defect formation in various systems from the early universe, condensed-matter systems to ultracold atomic systems. We explore the universal real-time dynamics in an array of coupled binary atomic Bose-Einstein condensates in optical lattices, which undergo a spontaneous symmetry breaking from the symmetric Rabi oscillation to the broken-symmetry self-trapping. In addition to Goldstone modes, there exist gapped Higgs modes whose excitation gap vanishes at the critical point. In the slow passage through the critical point, we analytically find that the symmetry-breaking dynamics obeys the Kibble-Zurek mechanism. From the scalings of bifurcation delay and domain formation, we numerically extract two Kibble-Zurek exponents, b1=ν/(1+ν z) and b2=1/(1+ν z) , which give the static correlation-length critical exponent ν and the dynamic critical exponent z. Our approach provides an efficient way for the simultaneous determination of the critical exponents ν and z for a continuous phase transition.

  8. Extended inclusive fitness theory: synergy and assortment drives the evolutionary dynamics in biology and economics.

    Science.gov (United States)

    Jaffe, Klaus

    2016-01-01

    W.D. Hamilton's Inclusive Fitness Theory explains the conditions that favor the emergence and maintenance of social cooperation. Today we know that these include direct and indirect benefits an agent obtains by its actions, and through interactions with kin and with genetically unrelated individuals. That is, in addition to kin-selection, assortation or homophily, and social synergies drive the evolution of cooperation. An Extended Inclusive Fitness Theory (EIFT) synthesizes the natural selection forces acting on biological evolution and on human economic interactions by assuming that natural selection driven by inclusive fitness produces agents with utility functions that exploit assortation and synergistic opportunities. This formulation allows to estimate sustainable cost/benefit threshold ratios of cooperation among organisms and/or economic agents, using existent analytical tools, illuminating our understanding of the dynamic nature of society, the evolution of cooperation among kin and non-kin, inter-specific cooperation, co-evolution, symbioses, division of labor and social synergies. EIFT helps to promote an interdisciplinary cross fertilization of the understanding of synergy by, for example, allowing to describe the role for division of labor in the emergence of social synergies, providing an integrated framework for the study of both, biological evolution of social behavior and economic market dynamics. Another example is a bio-economic understanding of the motivations of terrorists, which identifies different forms of terrorism.

  9. Dynamics of a pneumatic artificial muscle actuation system driving a trailing edge flap

    International Nuclear Information System (INIS)

    Woods, Benjamin K S; Kothera, Curt S; Wang, Gang; Wereley, Norman M

    2014-01-01

    This study presents a time domain dynamic model of an antagonistic pneumatic artificial muscle (PAM) driven trailing edge flap (TEF) system for next generation active helicopter rotors. Active rotor concepts are currently being widely researched in the rotorcraft community as a means to provide a significant leap forward in performance through primary aircraft control, vibration mitigation and noise reduction. Recent work has shown PAMs to be a promising candidate for active rotor actuation due to their combination of high force, large stroke, light weight, and suitable bandwidth. When arranged into biologically inspired agonist/antagonist muscle pairs they can produce bidirectional torques for effectively driving a TEF. However, there are no analytical dynamic models in the literature that can accurately capture the behavior of such systems across the broad range of frequencies required for this demanding application. This work combines mechanical, pneumatic, and aerodynamic component models into a global flap system model developed for the Bell 407 rotor system. This model can accurately predict pressure, force, and flap angle response to pneumatic control valve inputs over a range of operating frequencies from 7 to 35 Hz (1/rev to 5/rev for the Bell 407) and operating pressures from 30 to 90 psi. (paper)

  10. Dynamics of a pneumatic artificial muscle actuation system driving a trailing edge flap

    Science.gov (United States)

    Woods, Benjamin K. S.; Kothera, Curt S.; Wang, Gang; Wereley, Norman M.

    2014-09-01

    This study presents a time domain dynamic model of an antagonistic pneumatic artificial muscle (PAM) driven trailing edge flap (TEF) system for next generation active helicopter rotors. Active rotor concepts are currently being widely researched in the rotorcraft community as a means to provide a significant leap forward in performance through primary aircraft control, vibration mitigation and noise reduction. Recent work has shown PAMs to be a promising candidate for active rotor actuation due to their combination of high force, large stroke, light weight, and suitable bandwidth. When arranged into biologically inspired agonist/antagonist muscle pairs they can produce bidirectional torques for effectively driving a TEF. However, there are no analytical dynamic models in the literature that can accurately capture the behavior of such systems across the broad range of frequencies required for this demanding application. This work combines mechanical, pneumatic, and aerodynamic component models into a global flap system model developed for the Bell 407 rotor system. This model can accurately predict pressure, force, and flap angle response to pneumatic control valve inputs over a range of operating frequencies from 7 to 35 Hz (1/rev to 5/rev for the Bell 407) and operating pressures from 30 to 90 psi.

  11. Controlled Growth of Large-Area Aligned Single-Crystalline Organic Nanoribbon Arrays for Transistors and Light-Emitting Diodes Driving

    Science.gov (United States)

    Wang, Wei; Wang, Liang; Dai, Gaole; Deng, Wei; Zhang, Xiujuan; Jie, Jiansheng; Zhang, Xiaohong

    2017-10-01

    Organic field-effect transistors (OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm2 V-1 s-1, demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene (BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 × 10 cm2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed. By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm2 V-1 s-1 (average mobility 1.2 cm2 V-1 s-1) and 3.0 cm2 V-1 s-1 (average mobility 2.0 cm2 V-1 s-1), respectively. They both have a high on/off ratio ( I on/ I off) > 109. The performance can well satisfy the requirements for light-emitting diodes driving.

  12. Ultrasonic Phased Array Assessment of the Interference Fit and Leak Path of the North Anna Unit 2 Control Rod Drive Mechanism Nozzle 63 with Destructive Validation

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Susan L.; Cinson, Anthony D.; MacFarlan, Paul J.; Hanson, Brady D.; Mathews, Royce

    2012-08-01

    The objective of this investigation was to evaluate the efficacy of ultrasonic testing (UT) for primary water leak path assessments of reactor pressure vessel (RPV) upper head penetrations. Operating reactors have experienced leakage when stress corrosion cracking of nickel-based alloy penetrations allowed primary water into the annulus of the interference fit between the penetration and the low-alloy steel RPV head. In this investigation, UT leak path data were acquired for an Alloy 600 control rod drive mechanism nozzle penetration, referred to as Nozzle 63, which was removed from the North Anna Unit 2 reactor when the RPV head was replaced in 2002. In-service inspection prior to the head replacement indicated that Nozzle 63 had a probable leakage path through the interference fit region. Nozzle 63 was examined using a phased-array UT probe with a 5.0-MHz, eight-element annular array. Immersion data were acquired from the nozzle inner diameter surface. The UT data were interpreted by comparing to responses measured on a mockup penetration with known features. Following acquisition of the UT data, Nozzle 63 was destructively examined to determine if the features identified in the UT examination, including leakage paths and crystalline boric acid deposits, could be visually confirmed. Additional measurements of boric acid deposit thickness and low-alloy steel wastage were made to assess how these factors affect the UT response. The implications of these findings for interpreting UT leak path data are described.

  13. Drive-train dynamics technology - State-of-the-art and design of a test facility for advanced development

    Science.gov (United States)

    Badgley, R. H.; Fleming, D. P.; Smalley, A. J.

    1975-01-01

    A program for the development and verification of drive-train dynamic technology is described along with its basis and the results expected from it. A central feature of this program is a drive-train test facility designed for the testing and development of advanced drive-train components, including shaft systems, dampers, and couplings. Previous efforts in designing flexible dynamic drive-train systems are reviewed, and the present state of the art is briefly summarized. The design of the test facility is discussed with major attention given to the formulation of the test-rig concept, dynamic scaling of model shafts, and the specification of design parameters. Specific efforts envisioned for the test facility are briefly noted, including evaluations of supercritical test shafts, stability thresholds for various sources and types of instabilities that can exist in shaft systems, effects of structural flexibility on the dynamic performance of dampers, and methods for vibration control in two-level and three-level flexible shaft systems.

  14. Nonlinear dynamics of a friction-limited drive: Application to a chain continuously variable transmission (CVT) system

    Science.gov (United States)

    Srivastava, Nilabh; Haque, Imtiaz

    2009-03-01

    Over the past two decades, extensive research has been conducted on developing vehicle transmissions that meet the goals of reduced exhaust emissions and increased vehicle efficiency. A continuously variable transmission is an emerging automotive transmission technology that offers a continuum of gear ratios between desired limits. A chain CVT is a friction-limited drive whose dynamic performance and torque capacity rely significantly on the friction characteristic of the contact patch between the chain and the pulley. Although a CVT helps to maximize the vehicle fuel economy, its complete potential has not been accomplished in a mass-production vehicle. The present research focuses on developing models to analyze friction-induced nonlinear dynamics of a chain CVT drive and identify possible mechanisms that cause degradation of the overall dynamic performance by inducing chaos and self-sustained vibrations in the system. Two different mathematical models of friction, which characterize different operating or loading conditions, are embedded into a detailed planar multibody model of chain CVT in order to capture the various friction-induced effects in the system. Tools such as stick-slip oscillator dynamics, Lyapunov exponents, phase-space reconstruction, and recurrence plotting are incorporated to characterize the nonlinear dynamics of such a friction-limited system. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of friction characteristics on the nonlinear dynamics and torque transmitting capacity of a chain CVT drive.

  15. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  16. A dynamically tunable plasmonic multi-functional device based on graphene nano-sheet pair arrays

    Science.gov (United States)

    Wang, Wei; Meng, Zhao; Liang, Ruisheng; Chen, Shijie; Ding, Li; Wang, Faqiang; Liu, Hongzhan; Meng, Hongyun; Wei, Zhongchao

    2018-05-01

    Dynamically tunable plasmonic multi-functional is particularly desirable for various nanotechnological applications. In this paper, graphene nano-sheet pair arrays separated by a substrate, which can act as a dynamically tunable plasmonic band stop filter with transmission at resonance wavelength lower than 1%, a high sensitivity refractive index sensor with sensitivity up to 4879 nm/RIU, figure of merit of 40.66 and a two circuit optical switch with the modulation depth up to 0.998, are proposed and numerically investigated. These excellent optical performances are calculated by using FDTD numerical modeling and theoretical deduction. Simulation results show that a slight variation of chemical potential of the graphene nano-sheet can achieve significant resonance wavelength shifts. In additional, the resonance wavelength and transmission of this plasmonic device can be tuned easily by two voltages owing to the simple patterned graphene. These studies may have great potential in fabrication of multi-functional and dynamically tunable optoelectronic integrated devices.

  17. Dynamic experiment design regularization approach to adaptive imaging with array radar/SAR sensor systems.

    Science.gov (United States)

    Shkvarko, Yuriy; Tuxpan, José; Santos, Stewart

    2011-01-01

    We consider a problem of high-resolution array radar/SAR imaging formalized in terms of a nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) of the random wavefield scattered from a remotely sensed scene observed through a kernel signal formation operator and contaminated with random Gaussian noise. First, the Sobolev-type solution space is constructed to specify the class of consistent kernel SSP estimators with the reproducing kernel structures adapted to the metrics in such the solution space. Next, the "model-free" variational analysis (VA)-based image enhancement approach and the "model-based" descriptive experiment design (DEED) regularization paradigm are unified into a new dynamic experiment design (DYED) regularization framework. Application of the proposed DYED framework to the adaptive array radar/SAR imaging problem leads to a class of two-level (DEED-VA) regularized SSP reconstruction techniques that aggregate the kernel adaptive anisotropic windowing with the projections onto convex sets to enforce the consistency and robustness of the overall iterative SSP estimators. We also show how the proposed DYED regularization method may be considered as a generalization of the MVDR, APES and other high-resolution nonparametric adaptive radar sensing techniques. A family of the DYED-related algorithms is constructed and their effectiveness is finally illustrated via numerical simulations.

  18. Dynamic Evolution of the Evaporating Liquid-Vapor Interface in Micropillar Arrays.

    Science.gov (United States)

    Antao, Dion S; Adera, Solomon; Zhu, Yangying; Farias, Edgardo; Raj, Rishi; Wang, Evelyn N

    2016-01-19

    Capillary assisted passively pumped thermal management devices have gained importance due to their simple design and reduction in energy consumption. The performance of these devices is strongly dependent on the shape of the curved interface between the liquid and vapor phases. We developed a transient laser interferometry technique to investigate the evolution of the shape of the liquid-vapor interface in micropillar arrays during evaporation heat transfer. Controlled cylindrical micropillar arrays were fabricated on the front side of a silicon wafer, while thin-film heaters were deposited on the reverse side to emulate a heat source. The shape of the meniscus was determined using the fringe patterns resulting from interference of a monochromatic beam incident on the thin liquid layer. We studied the evolution of the shape of the meniscus on these surfaces under various operating conditions including varying the micropillar geometry and the applied heating power. By monitoring the transient behavior of the evaporating liquid-vapor interface, we accurately measured the absolute location and shape of the meniscus and calculated the contact angle and the maximum capillary pressure. We demonstrated that the receding contact angle which determines the capillary pumping limit is independent of the microstructure geometry and the rate of evaporation (i.e., the applied heating power). The results of this study provide fundamental insights into the dynamic behavior of the liquid-vapor interface in wick structures during phase-change heat transfer.

  19. Probing the Dynamics of Cellular Traction Forces with Magnetic Micropost Arrays

    Science.gov (United States)

    Kramer, Corinne; Chen, Christopher; Reich, Daniel

    2009-03-01

    Mechanical forces on living cells are associated with changes in cellular function. For example, vascular smooth muscle cells are known to undergo a mechanical feedback response to increased stress, which can result in atherosclerosis. We have recently developed a magnetic micropost array, a novel device for measuring cellular traction forces that simultaneously enables the application of localized external forces to cells. The device consists of an array of micrometer scale elastomeric posts that act as force sensors for cells cultured on their tips. An external force is applied to the adherent surface of a cell via a magnetic torque on a cobalt nanowire embedded in a single post. Initial results showed an active and non-local cellular response to applied forces in mouse fibroblast cells.ootnotetextN. Sniadecki, et. al, Proc Natl Acad Sci, 104, 14553 (2007). We will present results on the spatially resolved dynamics of traction forces exerted by smooth muscle cells over time in response to constant and time-varying stimulation. The observation of biochemical and mechanical regulation of the subcellular redistribution of force may allow insights into cellular mechanotransduction and control of cell function.

  20. Nonlinear dynamics of spring softening and hardening in folded-mems comb drive resonators

    KAUST Repository

    Elshurafa, Amro M.

    2011-08-01

    This paper studies analytically and numerically the spring softening and hardening phenomena that occur in electrostatically actuated microelectromechanical systems comb drive resonators utilizing folded suspension beams. An analytical expression for the electrostatic force generated between the combs of the rotor and the stator is derived and takes into account both the transverse and longitudinal capacitances present. After formulating the problem, the resulting stiff differential equations are solved analytically using the method of multiple scales, and a closed-form solution is obtained. Furthermore, the nonlinear boundary value problem that describes the dynamics of inextensional spring beams is solved using straightforward perturbation to obtain the linear and nonlinear spring constants of the beam. The analytical solution is verified numerically using a Matlab/Simulink environment, and the results from both analyses exhibit excellent agreement. Stability analysis based on phase plane trajectory is also presented and fully explains previously reported empirical results that lacked sufficient theoretical description. Finally, the proposed solutions are, once again, verified with previously published measurement results. The closed-form solutions provided are easy to apply and enable predicting the actual behavior of resonators and gyroscopes with similar structures. © 2011 IEEE.

  1. Transmission or Within-Host Dynamics Driving Pulses of Zoonotic Viruses in Reservoir–Host Populations

    Science.gov (United States)

    Plowright, Raina K.; Peel, Alison J.; Streicker, Daniel G.; Gilbert, Amy T.; McCallum, Hamish; Wood, James; Baker, Michelle L.; Restif, Olivier

    2016-01-01

    Progress in combatting zoonoses that emerge from wildlife is often constrained by limited knowledge of the biology of pathogens within reservoir hosts. We focus on the host–pathogen dynamics of four emerging viruses associated with bats: Hendra, Nipah, Ebola, and Marburg viruses. Spillover of bat infections to humans and domestic animals often coincides with pulses of viral excretion within bat populations, but the mechanisms driving such pulses are unclear. Three hypotheses dominate current research on these emerging bat infections. First, pulses of viral excretion could reflect seasonal epidemic cycles driven by natural variations in population densities and contact rates among hosts. If lifelong immunity follows recovery, viruses may disappear locally but persist globally through migration; in either case, new outbreaks occur once births replenish the susceptible pool. Second, epidemic cycles could be the result of waning immunity within bats, allowing local circulation of viruses through oscillating herd immunity. Third, pulses could be generated by episodic shedding from persistently infected bats through a combination of physiological and ecological factors. The three scenarios can yield similar patterns in epidemiological surveys, but strategies to predict or manage spillover risk resulting from each scenario will be different. We outline an agenda for research on viruses emerging from bats that would allow for differentiation among the scenarios and inform development of evidence-based interventions to limit threats to human and animal health. These concepts and methods are applicable to a wide range of pathogens that affect humans, domestic animals, and wildlife. PMID:27489944

  2. Cellular Dynamics Drives the Emergence of Supracellular Structure in the Cyanobacterium, Phormidium sp. KS.

    Science.gov (United States)

    Sato, Naoki; Katsumata, Yutaro; Sato, Kaoru; Tajima, Naoyuki

    2014-11-28

    Motile filamentous cyanobacteria, such as Oscillatoria, Phormidium and Arthrospira, are ubiquitous in terrestrial and aquatic environments. As noted by Nägeli in 1860, many of them form complex three-dimensional or two-dimensional structures, such as biofilm, weed-like thalli, bundles of filaments and spirals, which we call supracellular structures. In all of these structures, individual filaments incessantly move back and forth. The structures are, therefore, macroscopic, dynamic structures that are continuously changing their microscopic arrangement of filaments. In the present study, we analyzed quantitatively the movement of individual filaments of Phormidium sp. KS grown on agar plates. Junctional pores, which have been proposed to drive cell movement by mucilage/slime secretion, were found to align on both sides of each septum. The velocity of movement was highest just after the reversal of direction and, then, attenuated exponentially to a final value before the next reversal of direction. This kinetics is compatible with the "slime gun" model. A higher agar concentration restricts the movement more severely and, thus, resulted in more spiral formation. The spiral is a robust form compatible with non-homogeneous movements of different parts of a long filament. We propose a model of spiral formation based on the microscopic movement of filaments.

  3. Cellular Dynamics Drives the Emergence of Supracellular Structure in the Cyanobacterium, Phormidium sp. KS

    Directory of Open Access Journals (Sweden)

    Naoki Sato

    2014-11-01

    Full Text Available Motile filamentous cyanobacteria, such as Oscillatoria, Phormidium and Arthrospira, are ubiquitous in terrestrial and aquatic environments. As noted by Nägeli in 1860, many of them form complex three-dimensional or two-dimensional structures, such as biofilm, weed-like thalli, bundles of filaments and spirals, which we call supracellular structures. In all of these structures, individual filaments incessantly move back and forth. The structures are, therefore, macroscopic, dynamic structures that are continuously changing their microscopic arrangement of filaments. In the present study, we analyzed quantitatively the movement of individual filaments of Phormidium sp. KS grown on agar plates. Junctional pores, which have been proposed to drive cell movement by mucilage/slime secretion, were found to align on both sides of each septum. The velocity of movement was highest just after the reversal of direction and, then, attenuated exponentially to a final value before the next reversal of direction. This kinetics is compatible with the “slime gun” model. A higher agar concentration restricts the movement more severely and, thus, resulted in more spiral formation. The spiral is a robust form compatible with non-homogeneous movements of different parts of a long filament. We propose a model of spiral formation based on the microscopic movement of filaments.

  4. High-dynamic range image projection using an auxiliary MEMS mirror array.

    Science.gov (United States)

    Hoskinson, Reynald; Stoeber, Boris

    2008-05-12

    We introduce a new concept to improve the contrast and peak brightness of conventional data projectors. Our method provides a non-homogenous light source by dynamically directing fractions of the light from the projector lamp before it reaches the display mechanism. This will supply more light to the areas that need it most, at the expense of the darker parts of the image. In effect, this method will produce a low resolution version of the image onto the image-forming element. To manipulate the light in this manner, we propose using an intermediate array of microelectromechanical system (MEMS) mirrors. By directing the light away from the dark parts earlier in the display chain, the amount of light that needs to be blocked will be reduced, thus decreasing the black level of the final image. Moreover, the ability to dynamically allocate more light to the bright parts of the image will allow for peak brightness higher than the average maximum brightness of display.

  5. Development of a High Dynamic Range Pixel Array Detector for Synchrotrons and XFELs

    Science.gov (United States)

    Weiss, Joel Todd

    Advances in synchrotron radiation light source technology have opened new lines of inquiry in material science, biology, and everything in between. However, x-ray detector capabilities must advance in concert with light source technology to fully realize experimental possibilities. X-ray free electron lasers (XFELs) place particularly large demands on the capabilities of detectors, and developments towards diffraction-limited storage ring sources also necessitate detectors capable of measuring very high flux [1-3]. The detector described herein builds on the Mixed Mode Pixel Array Detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging, and the Adaptive Gain Integrating Pixel Detector (AGIPD) developed for the European XFEL by a collaboration between Deustsches Elektronen-Synchrotron (DESY), the Paul-Scherrer-Institute (PSI), the University of Hamburg, and the University of Bonn, led by Heinz Graafsma [4, 5]. The feasibility of combining adaptive gain with charge removal techniques to increase dynamic range in XFEL experiments is assessed by simulating XFEL scatter with a pulsed infrared laser. The strategy is incorporated into pixel prototypes which are evaluated with direct current injection to simulate very high incident x-ray flux. A fully functional 16x16 pixel hybrid integrating x-ray detector featuring several different pixel architectures based on the prototypes was developed. This dissertation describes its operation and characterization. To extend dynamic range, charge is removed from the integration node of the front-end amplifier without interrupting integration. The number of times this process occurs is recorded by a digital counter in the pixel. The parameter limiting full well is thereby shifted from the size of an integration capacitor to the depth of a digital counter. The result is similar to that achieved by counting pixel array detectors, but the integrators presented here are designed to tolerate a

  6. Improved Protein Arrays for Quantitative Systems Analysis of the Dynamics of Signaling Pathway Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chin-Rang [National Inst. of Health (NIH), Bethesda, MD (United States). National Heart, Lung and Blood Inst.

    2013-12-11

    Astronauts and workers in nuclear plants who repeatedly exposed to low doses of ionizing radiation (IR, <10 cGy) are likely to incur specific changes in signal transduction and gene expression in various tissues of their body. Remarkable advances in high throughput genomics and proteomics technologies enable researchers to broaden their focus from examining single gene/protein kinetics to better understanding global gene/protein expression profiling and biological pathway analyses, namely Systems Biology. An ultimate goal of systems biology is to develop dynamic mathematical models of interacting biological systems capable of simulating living systems in a computer. This Glue Grant is to complement Dr. Boothman’s existing DOE grant (No. DE-FG02-06ER64186) entitled “The IGF1/IGF-1R-MAPK-Secretory Clusterin (sCLU) Pathway: Mediator of a Low Dose IR-Inducible Bystander Effect” to develop sensitive and quantitative proteomic technology that suitable for low dose radiobiology researches. An improved version of quantitative protein array platform utilizing linear Quantum dot signaling for systematically measuring protein levels and phosphorylation states for systems biology modeling is presented. The signals are amplified by a confocal laser Quantum dot scanner resulting in ~1000-fold more sensitivity than traditional Western blots and show the good linearity that is impossible for the signals of HRP-amplification. Therefore this improved protein array technology is suitable to detect weak responses of low dose radiation. Software is developed to facilitate the quantitative readout of signaling network activities. Kinetics of EGFRvIII mutant signaling was analyzed to quantify cross-talks between EGFR and other signaling pathways.

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

    Science.gov (United States)

    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.

  8. Dynamic Analysis of Heavy Vehicle Medium Duty Drive Shaft Using Conventional and Composite Material

    Science.gov (United States)

    Kumar, Ashwani; Jain, Rajat; Patil, Pravin P.

    2016-09-01

    The main highlight of this study is structural and modal analysis of single piece drive shaft for selection of material. Drive shaft is used for torque carrying from vehicle transmission to rear wheel differential system. Heavy vehicle medium duty transmission drive shaft was selected as research object. Conventional materials (Steel SM45 C, Stainless Steel) and composite materials (HS carbon epoxy, E Glass Polyester Resin Composite) were selected for the analysis. Single piece composite material drive shaft has advantage over conventional two-piece steel drive shaft. It has higher specific strength, longer life, less weight, high critical speed and higher torque carrying capacity. The main criteria for drive shaft failure are strength and weight. Maximum modal frequency obtained is 919 Hz. Various harmful vibration modes (lateral vibration and torsional vibration) were identified and maximum deflection region was specified. For single-piece drive shaft the natural bending frequency should be higher because it is subjected to torsion and shear stress. Single piece drive shaft was modelled using Solid Edge and Pro-E. Finite Element Analysis was used for structural and modal analysis with actual running boundary condition like frictional support, torque and moment. FEA simulation results were validated with experimental literature results.

  9. A study of dynamics performance improvement by rear right and left independent drive system

    Science.gov (United States)

    Sugano, Takashi; Fukuba, Hitoshi; Suetomi, Takamasa

    2010-11-01

    In this study, methods of motion control on a rear right and left independent electric motor drive vehicle and the benefit for drivers when using this configuration were researched. The system offers direct yaw moment control (DYC) function and it is possible to compensate for the vehicle turning motion. On the other hand, a rear drive vehicle often becomes unstable at a situation of acceleration in a turn. Even if the DYC system controls the vehicle motion, there are performance limits. One of the cause considered is that the characteristics of rear tyres are changed by the driving force. Control methods that focused especially on this point were examined, and the performance of independent drive system was evaluated by a simulation. Moreover, the effects on driver were confirmed with a driving simulator. The effectiveness of the system was confirmed from these results.

  10. Myosin-Va and Dynamic Actin Oppose Microtubules to Drive Long-Range Organelle Transport

    Science.gov (United States)

    Evans, Richard D.; Robinson, Christopher; Briggs, Deborah A.; Tooth, David J.; Ramalho, Jose S.; Cantero, Marta; Montoliu, Lluis; Patel, Shyamal; Sviderskaya, Elena V.; Hume, Alistair N.

    2014-01-01

    Summary In animal cells, microtubule and actin tracks and their associated motors (dynein, kinesin, and myosin) are thought to regulate long- and short-range transport, respectively [1–8]. Consistent with this, microtubules extend from the perinuclear centrosome to the plasma membrane and allow bidirectional cargo transport over long distances (>1 μm). In contrast, actin often comprises a complex network of short randomly oriented filaments, suggesting that myosin motors move cargo short distances. These observations underpin the “highways and local roads” model for transport along microtubule and actin tracks [2]. The “cooperative capture” model exemplifies this view and suggests that melanosome distribution in melanocyte dendrites is maintained by long-range transport on microtubules followed by actin/myosin-Va-dependent tethering [5, 9]. In this study, we used cell normalization technology to quantitatively examine the contribution of microtubules and actin/myosin-Va to organelle distribution in melanocytes. Surprisingly, our results indicate that microtubules are essential for centripetal, but not centrifugal, transport. Instead, we find that microtubules retard a centrifugal transport process that is dependent on myosin-Va and a population of dynamic F-actin. Functional analysis of mutant proteins indicates that myosin-Va works as a transporter dispersing melanosomes along actin tracks whose +/barbed ends are oriented toward the plasma membrane. Overall, our data highlight the role of myosin-Va and actin in transport, and not tethering, and suggest a new model in which organelle distribution is determined by the balance between microtubule-dependent centripetal and myosin-Va/actin-dependent centrifugal transport. These observations appear to be consistent with evidence coming from other systems showing that actin/myosin networks can drive long-distance organelle transport and positioning [10, 11]. PMID:25065759

  11. A Forest Structure Dynamics Model for Driving Three-Dimensional Canopy Radiative Transfer Simulations

    Science.gov (United States)

    Yang, W.; Kobayashi, H.; Kondoh, A.

    2016-12-01

    Three-dimensional (3-D) Monte Carlo (MC)-based radiative transfer (RT) models can simulate highly detailed forest environments, and have produced simulations that agree well with observations; thus, they are routinely used for benchmarking in intercomparisons of RT models. However, MC-based RT models have not been widely applied to the development of inversion algorithms for generating global remote sensing products of forests, due mainly to the difficulties in obtaining realistic forest structures for a variety of forest biomes. In this study, we developed a Forest Structure Dynamics Model (FSDM) to facilitate the application of MC-based RT models to global forests. In this model, the tree architectures are determined based on allometric equations, and the tree locations within a study domain are determined by statistical distributions. The performance of the FSDM was evaluated using field measurements of forest landscapes at two sites located at Järvselja, Estonia and the Poker Flat Research Range (PFRR), USA, respectively. The bidirectional reflectance factor (BRF) for the two study sites was simulated by an MC-based RT model, based on the measured forest stands and modeled stands from the FSDM. A comparison of the results demonstrated that the simulated BRF based on the measured forest stands agreed well with the simulated BRF based on the modeled stands from the FSDM for the two study sites. The applicability of the FSDM to a leaf area index (LAI) retrieval algorithm was also verified using simulations from the MC-based RT model. The results indicate that the FSDM can provide reasonable forest structures to drive 3-D canopy RT models, with no loss of simulation accuracy. When combined with several existing field data sets and satellite products, the FSDM can be used to generate a typical stand structure database for global forest biomes.

  12. Application of second order sliding mode algorithms for output feedback control in hydraulic cylinder drives with profound valve dynamics

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben O.

    2016-01-01

    The application of second order sliding mode algorithms for output feedback control in hydraulic valve-cylinder drives appear attractive due to their simple realization and parametrization, and strong robustness toward bounded parameter variations and uncertainties. However, intrinsic nonlinear...... consideration are applied for position tracking control of a hydraulic valve-cylinder drive exhibiting strong variations in inertia- and gravitational loads, and furthermore suffer from profound valve dynamics. Results demonstrate that both the twisting- and super twisting algorithms may be successfully applied...... dynamic effects of hydraulic valves such as slew rate limitations and time delays arising in the electrical and mechanical amplification stages limits the applicability of such methods, and may lead to partial losses of robustness and limit cycles/oscillations in the outputs, internal states and the valve...

  13. Projective synchronization in drive-response dynamical networks of partially linear systems with time-varying coupling delay

    International Nuclear Information System (INIS)

    Sun Mei; Zeng Changyan; Tian Lixin

    2008-01-01

    Recently, projective synchronization (PS) has been widely studied in more than one system. In this Letter, we propose a linear controller and an updated law to realize the PS in drive-response dynamical networks of partially linear systems with time-varying coupling delay, based on the Lyapunov stability theory. A sufficient condition is obtained. Moreover, numerical simulations are provided to verify the correctness and effectiveness of the scheme

  14. A high-throughput method for GMO multi-detection using a microfluidic dynamic array.

    Science.gov (United States)

    Brod, Fábio Cristiano Angonesi; van Dijk, Jeroen P; Voorhuijzen, Marleen M; Dinon, Andréia Zilio; Guimarães, Luis Henrique S; Scholtens, Ingrid M J; Arisi, Ana Carolina Maisonnave; Kok, Esther J

    2014-02-01

    The ever-increasing production of genetically modified crops generates a demand for high-throughput DNA-based methods for the enforcement of genetically modified organisms (GMO) labelling requirements. The application of standard real-time PCR will become increasingly costly with the growth of the number of GMOs that is potentially present in an individual sample. The present work presents the results of an innovative approach in genetically modified crops analysis by DNA based methods, which is the use of a microfluidic dynamic array as a high throughput multi-detection system. In order to evaluate the system, six test samples with an increasing degree of complexity were prepared, preamplified and subsequently analysed in the Fluidigm system. Twenty-eight assays targeting different DNA elements, GM events and species-specific reference genes were used in the experiment. The large majority of the assays tested presented expected results. The power of low level detection was assessed and elements present at concentrations as low as 0.06 % were successfully detected. The approach proposed in this work presents the Fluidigm system as a suitable and promising platform for GMO multi-detection.

  15. The dynamics of a polariton dimer in a disordered coupled array of cavities

    Science.gov (United States)

    Aiyejina, Abuenameh; Andrews, Roger

    2018-03-01

    We investigate the effect of disorder in the laser intensity on the dynamics of dark-state polaritons in an array of 20 cavities, each containing an ensemble of four-level atoms that is described by a Bose-Hubbard Hamiltonian. We examine the evolution of the polariton number in the cavities starting from a state with either one or two polaritons in one of the cavities. For the case of a single polariton without disorder in the laser intensity, we calculate the wavefunction of the polariton and find that it disperses away from the initial cavity with time. The addition of disorder results in minimal suppression of the dispersal of the wavefunction. In the case of two polaritons with an on-site repulsion to hopping strength ratio of 20, we find that the polaritons form a repulsively bound state or dimer. Without disorder the dimer wavefunction disperses similarly to the single polariton wavefunction but over a longer time period. The addition of sufficiently strong disorder results in localization of the polariton dimer. The localization length is found to be described by a power law with exponent - 1.31. We also find that we can localise the dimer at any given time by switching on the disorder.

  16. Spatiotemporal dynamics and plastic flow of vortices in superconductors with periodic arrays of pinning sites

    Science.gov (United States)

    Reichhardt, C.; Groth, J.; Olson, C. J.; Field, Stuart B.; Nori, Franco

    1996-12-01

    We present simulations of flux-gradient-driven superconducting rigid vortices interacting with square and triangular arrays of columnar pinning sites in an increasing external magnetic field. These simulations allow us to quantitatively relate spatiotemporal microscopic information of the vortex lattice with typically measured macroscopic quantities, such as the magnetization M(H). The flux lattice does not become completely commensurate with the pinning sites throughout the sample at the magnetization matching peaks, but forms a commensurate lattice in a region close to the edge of the sample. Matching fields related to unstable vortex configurations do not produce peaks in M(H). We observe a variety of evolving complex flux profiles, including flat terraces or plateaus separated by winding current-carrying strings and, near the peaks in M(H), plateaus only in certain regions, which move through the sample as the field increases. Several short videos, illustrating several particular cases of the type of dynamics described here, are available at http://www-personal.engin.umich.edu/~nori.

  17. Spatiotemporal dynamics and plastic flow of vortices in superconductors with periodic arrays of pinning sites

    International Nuclear Information System (INIS)

    Reichhardt, C.; Groth, J.; Olson, C.J.; Field, S.B.; Nori, F.

    1996-01-01

    We present simulations of flux-gradient-driven superconducting rigid vortices interacting with square and triangular arrays of columnar pinning sites in an increasing external magnetic field. These simulations allow us to quantitatively relate spatiotemporal microscopic information of the vortex lattice with typically measured macroscopic quantities, such as the magnetization M(H). The flux lattice does not become completely commensurate with the pinning sites throughout the sample at the magnetization matching peaks, but forms a commensurate lattice in a region close to the edge of the sample. Matching fields related to unstable vortex configurations do not produce peaks in M(H). We observe a variety of evolving complex flux profiles, including flat terraces or plateaus separated by winding current-carrying strings and, near the peaks in M(H), plateaus only in certain regions, which move through the sample as the field increases. Several short videos, illustrating several particular cases of the type of dynamics described here, are available at http://www-personal.engin.umich.edu/--nori. copyright 1996 The American Physical Society

  18. High Dynamic Range adaptive ΔΣ-based Focal Plane Array architecture

    KAUST Repository

    Yao, Shun

    2012-10-16

    In this paper, an Adaptive Delta-Sigma based architecture for High Dynamic Range (HDR) Focal Plane Arrays is presented. The noise shaping effect of the Delta-Sigma modulation in the low end, and the distortion noise induced in the high end of Photo-diode current were analyzed in detail. The proposed architecture can extend the DR for about 20N log2 dB at the high end of Photo-diode current with an N bit Up-Down counter. At the low end, it can compensate for the larger readout noise by employing Extended Counting. The Adaptive Delta-Sigma architecture employing a 4-bit Up-Down counter achieved about 160dB in the DR, with a Peak SNR (PSNR) of 80dB at the high end. Compared to the other HDR architectures, the Adaptive Delta-Sigma based architecture provides the widest DR with the best SNR performance in the extended range.

  19. NOTE: A dynamic optical imaging phantom based on an array of semiconductor diodes

    Science.gov (United States)

    Hebden, Jeremy C.; Correia, Teresa; Khakoo, Imran; Gibson, Adam P.; Everdell, N. L.

    2008-11-01

    An electrically-activated phantom for evaluating diffuse optical imaging systems has been designed based on an array of semiconductor diodes which are used to heat a thermochromic dye embedded in a solidified polyester resin with tissue-like optical properties. The array allows individual diodes to be addressed sequentially, thus simulating the movement of a small volume of contrasting optical absorption. Two designs of diode-array phantom are described and results of imaging experiments are presented.

  20. A dynamic optical imaging phantom based on an array of semiconductor diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hebden, Jeremy C; Correia, Teresa; Khakoo, Imran; Gibson, Adam P; Everdell, N L [Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2008-11-07

    An electrically-activated phantom for evaluating diffuse optical imaging systems has been designed based on an array of semiconductor diodes which are used to heat a thermochromic dye embedded in a solidified polyester resin with tissue-like optical properties. The array allows individual diodes to be addressed sequentially, thus simulating the movement of a small volume of contrasting optical absorption. Two designs of diode-array phantom are described and results of imaging experiments are presented. (note)

  1. APPLIED PROBLEMS OF CURVILINEAR MOTION DYNAMICS OF ALL-WHEEL DRIVE TRACTION MEANS

    Directory of Open Access Journals (Sweden)

    G. S. Gorin

    2014-01-01

    Full Text Available Fundamental principles for hybrid theory on turning of an all-wheel drive system are given in the paper. The paper shows expediency of accounting longitudinal additional tangential reactions (parasitic forces in contacts of central and lateral wheels with foundation. Algorithms for calculating additional tangential reactions have been proposed in the paper. The paper presents calculation kinematics model for turning of steered and rigid bogie with inter-wheel differential at various axial drive.

  2. Dynamic characterisation of the head media interface in hard disk drives using novel sensor systems

    CERN Document Server

    Tunstall, G A

    2002-01-01

    Hard disk drives function perfectly satisfactorily when used in a stable environment, but in certain applications they are subjected to shock and vibration. During the work reported in this thesis it has been found that when typical hard disk drives are subjected to vibration, data transfer failure is found to be significant at frequencies between 440Hz and 700Hz, at an extreme, failing at only 1g of sinusoidal vibration. These failures can largely be attributed to two key components: the suspension arm and the hard disk. At non-critical frequencies of vibration the typical hard disk drive can reliably transfer data whilst subjected to as much as 45g. When transferring data to the drive controller, the drive's operations are controlled and monitored using BIOS commands. Examining the embedded error signals proved that the drive predominantly failed due to tracking errors. Novel piezo-electric sensors have been developed to measure unobtrusively suspension arm and disk motion, the results from which show the d...

  3. Multivalent Soluble Antigen Arrays Exhibit High Avidity Binding and Modulation of B Cell Receptor-Mediated Signaling to Drive Efficacy against Experimental Autoimmune Encephalomyelitis.

    Science.gov (United States)

    Hartwell, Brittany L; Pickens, Chad J; Leon, Martin; Berkland, Cory

    2017-06-12

    A pressing need exists for antigen-specific immunotherapies (ASIT) that induce selective tolerance in autoimmune disease while avoiding deleterious global immunosuppression. Multivalent soluble antigen arrays (SAgA PLP:LABL ), consisting of a hyaluronic acid (HA) linear polymer backbone cografted with multiple copies of autoantigen (PLP) and cell adhesion inhibitor (LABL) peptides, are designed to induce tolerance to a specific multiple sclerosis (MS) autoantigen. Previous studies established that hydrolyzable SAgA PLP:LABL , employing a degradable linker to codeliver PLP and LABL, was therapeutic in experimental autoimmune encephalomyelitis (EAE) in vivo and exhibited antigen-specific binding with B cells, targeted the B cell receptor (BCR), and dampened BCR-mediated signaling in vitro. Our results pointed to sustained BCR engagement as the SAgA PLP:LABL therapeutic mechanism, so we developed a new version of the SAgA molecule using nonhydrolyzable conjugation chemistry, hypothesizing it would enhance and maintain the molecule's action at the cell surface to improve efficacy. "Click SAgA" (cSAgA PLP:LABL ) uses hydrolytically stable covalent conjugation chemistry (Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC)) rather than a hydrolyzable oxime bond to attach PLP and LABL to HA. We explored cSAgA PLP:LABL B cell engagement and modulation of BCR-mediated signaling in vitro through flow cytometry binding and calcium flux signaling assays. Indeed, cSAgA PLP:LABL exhibited higher avidity B cell binding and greater dampening of BCR-mediated signaling than hydrolyzable SAgA PLP:LABL . Furthermore, cSAgA PLP:LABL exhibited significantly enhanced in vivo efficacy compared to hydrolyzable SAgA PLP:LABL , achieving equivalent efficacy at one-quarter of the dose. These results indicate that nonhydrolyzable conjugation increased the avidity of cSAgA PLP:LABL to drive in vivo efficacy through modulated BCR-mediated signaling.

  4. Real-time monitoring of cellular dynamics using a microfluidic cell culture system with integrated electrode array and potentiostat

    DEFF Research Database (Denmark)

    Zor, Kinga; Vergani, M.; Heiskanen, Arto

    2011-01-01

    A versatile microfluidic, multichamber cell culture and analysis system with an integrated electrode array and potentiostat suitable for electrochemical detection and microscopic imaging is presented in this paper. The system, which allows on-line electrode cleaning and modification, was developed...... for real-time monitoring of cellular dynamics, exemplified in this work by monitoring of redox metabolism inside living yeast cells and dopamine release from PC12 cells....

  5. Dynamic Friction Parameter Identification Method with LuGre Model for Direct-Drive Rotary Torque Motor

    Directory of Open Access Journals (Sweden)

    Xingjian Wang

    2016-01-01

    Full Text Available Attainment of high-performance motion/velocity control objectives for the Direct-Drive Rotary (DDR torque motor should fully consider practical nonlinearities in controller design, such as dynamic friction. The LuGre model has been widely utilized to describe nonlinear friction behavior; however, parameter identification for the LuGre model remains a challenge. A new dynamic friction parameter identification method for LuGre model is proposed in this study. Static parameters are identified through a series of constant velocity experiments, while dynamic parameters are obtained through a presliding process. Novel evolutionary algorithm (NEA is utilized to increase identification accuracy. Experimental results gathered from the identification experiments conducted in the study for a practical DDR torque motor control system validate the effectiveness of the proposed method.

  6. Dynamic characterisation of the head media interface in hard disk drives using novel sensor systems

    International Nuclear Information System (INIS)

    Tunstall, Glen Alan

    2002-01-01

    Hard disk drives function perfectly satisfactorily when used in a stable environment, but in certain applications they are subjected to shock and vibration. During the work reported in this thesis it has been found that when typical hard disk drives are subjected to vibration, data transfer failure is found to be significant at frequencies between 440Hz and 700Hz, at an extreme, failing at only 1g of sinusoidal vibration. These failures can largely be attributed to two key components: the suspension arm and the hard disk. At non-critical frequencies of vibration the typical hard disk drive can reliably transfer data whilst subjected to as much as 45g. When transferring data to the drive controller, the drive's operations are controlled and monitored using BIOS commands. Examining the embedded error signals proved that the drive predominantly failed due to tracking errors. Novel piezo-electric sensors have been developed to measure unobtrusively suspension arm and disk motion, the results from which show the disk to be the most significant failure mechanism, with its first mode of resonance at around 440Hz. The suspension arm movement has been found to be greatest at 1kHz. Extensive modelling of the flexure of the disk, clamped and unclamped, has been undertaken using finite element analysis. The theoretical modelling strongly reinforces the empirical results presented in this thesis. If suspension arm movement is not directly coupled with disk movement then a flying height variation is created. This, together with tracking variations, leads to data transfer corruption. This has been found to occur at 1kHz and 2kHz. An optical system has been developed and characterised for a novel and inexpensive flying height measurement system using compact disc player technology. (author)

  7. Mathematical modeling and dynamic simulation of a class of drive systems with permanent magnet synchronous motors

    Directory of Open Access Journals (Sweden)

    Mikhov M.

    2009-12-01

    Full Text Available The performance of a two-coordinate drive system with permanent magnet synchronous motors is analyzed and discussed in this paper. Both motors have been controlled in brushless DC motor mode in accordance with the rotor positions. Detailed study has been carried out by means of mathematical modeling and computer simulation for the respective transient and steady-state regimes at various load and work conditions. The research carried out as well as the results obtained can be used in the design, optimization and tuning of such types of drive systems. They could be also applied in the teaching process.

  8. Converter topologies and dynamical properties of an SR-motor drive

    Energy Technology Data Exchange (ETDEWEB)

    Silventoinen, P.; Tolsa, K.; Salo, J.; Pyrhoenen, J. [Department of Energy Technology, Laboratory of Electrical Engineering Lappeenranta University of Technology, Lappeenranta (Finland)

    1997-12-31

    Starting and reversing times of less than 40 A, torque ripple below 10 % and operational speeds over 5000 rpm can be achieved with 6/4 prototype switched reluctance motor drive. The drive efficiency approaches 80 percent but it is currently limited by high switching frequency. Peak currents of 50 A are needed in a 4.2 kW machine. An introduction to switched reluctance machines and their control is presented and experimental results of the prototype switched reluctance machine are shown. (orig.) 4 refs.

  9. Driving forces behind the increasing cardiovascular treatment intensity.A dynamic epidemiologic model of trends in Danish cardiovascular drug utilization.

    DEFF Research Database (Denmark)

    Kildemoes, Helle Wallach; Andersen, Morten

    Background: In many Western countries cardiovascular treatment intensity (DDD/1000 inhabitants/day, DDD/TID) has grown substantially during the last decades. Changed drug utilization pattern - rather than population ageing - was hypothesized to be the main driving force behind the growth....... Objectives: To investigate the driving forces behind the increasing treatment prevalence of cardiovascular drugs, in particular statins, by means of a dynamic epidemiologic drug utilization model. Methods: Material: All Danish residents older than 20 years by January 1, 1996 (4.0 million inhabitants), were...... followed with respect to out-of-hospital redemptions of cardiovascular prescription drugs in the period 1996-2005. The impact of population ageing on cardiovascular treatment intensity was investigated by comparing crude and age/gender standardised intensities. Epidemiologic model: We developed a three...

  10. Equivalent circuit-based analysis of CMUT cell dynamics in arrays.

    Science.gov (United States)

    Oguz, H K; Atalar, Abdullah; Köymen, Hayrettin

    2013-05-01

    Capacitive micromachined ultrasonic transducers (CMUTs) are usually composed of large arrays of closely packed cells. In this work, we use an equivalent circuit model to analyze CMUT arrays with multiple cells. We study the effects of mutual acoustic interactions through the immersion medium caused by the pressure field generated by each cell acting upon the others. To do this, all the cells in the array are coupled through a radiation impedance matrix at their acoustic terminals. An accurate approximation for the mutual radiation impedance is defined between two circular cells, which can be used in large arrays to reduce computational complexity. Hence, a performance analysis of CMUT arrays can be accurately done with a circuit simulator. By using the proposed model, one can very rapidly obtain the linear frequency and nonlinear transient responses of arrays with an arbitrary number of CMUT cells. We performed several finite element method (FEM) simulations for arrays with small numbers of cells and showed that the results are very similar to those obtained by the equivalent circuit model.

  11. Experimental study of implosion dynamics of multi-material nested wire-arrays on S-300 pulsed power generator

    International Nuclear Information System (INIS)

    Chernenko, A.S.; Smirnov, V.P.; Kingsep, A.S.

    2004-01-01

    On 'S-300' generator (700 kV, 4 MA, 70 ns) at the Kurchatov Institute, the experimental studies with multi-material wire array units are carried on aimed at creating the powerful X-ray source. The development of new diagnostic methods would definitely contribute to attain new data, which could help in explanation of X-ray emission mechanism of imploding multi-wire arrays that has not well understood yet. The experimental study of soft X-ray emission of different wire sets, different in both mass and composition, has been carried on in the same geometry. One of the purposes of these experiments was investigation of the wire array chemical composition influence on the implosion dynamics and stability. Study of the nested (cascade) liner dynamics shows that the minimal liner radius at the stagnation moment of time (2r ∼ 3 - 3.5 mm) recorded in the visible range by the streak camera fairly coincides with the outer diameter of the inner tungsten array of 4 mm. The same size is shown by the integral pinhole pictures obtained in the SXR range, without a filter. Unlike all these pictures, images obtained in the range E > 2 keV demonstrate the resulting state of Z-pinch in the form of a thin (∼ 0.2 mm) twisting filament. In addition, small space scales are typical of the liner pictures taken in the range of He- and H-like aluminum ions by means of a spectrograph. Thus, one may conclude that Al plasma of the outer liner passes into the inner space of the almost immovable W array where becomes trapped and compressed by the magnetic field. (author)

  12. Dynamics of non-Markovianity in the presence of a driving field

    Indian Academy of Sciences (India)

    In some conditions, it is shown that in the presence of a driving field, the $N_{\\rm BLP} increases in the resonance and non-resonance limits. We have also found the exact solution of the master equation in order to investigate the effect of temperature- and environment excited states. We have shown that the behaviour of ...

  13. Virtual Drive Testing of Adaptive Antenna Systems in Dynamic Propagation Scenarios for Vehicle Communications

    DEFF Research Database (Denmark)

    Fan, Wei; Hentilä, Lassi; Zhang, Fengchun

    2018-01-01

    Virtual drive testing (VDT) has gained great interest from both industry and academia, owing to its promise to replay field trials in a controllable laboratory condition. VDT is especially appealing for vehicle communication scenarios, where actual field trials can be difficult to carry out...

  14. Dynamics of non-Markovianity in the presence of a driving field

    Indian Academy of Sciences (India)

    Abstract. We investigate a two-level system in a cavity QED by considering the effects of amplitude damping, phase damping and driving field. We have studied the non-Markovianity in res- onance and non-resonance limits in the presence of these effects using Breuer–Laine–Piilo (BLP) non-Markovianity measure (NBLP).

  15. Rotor–stator contact dynamics using a non-ideal drive

    DEFF Research Database (Denmark)

    Lahriri, Said; Weber, H.I.Hans I.; Santos, I.F.Ilmar F.

    2012-01-01

    this for a conventional backup annular guide setup. It is reasonable to superpose an impact condition to the rub, where the rotor spin energy can be fully transformed into rotor lateral movements. Using a nonideal drive, i.e. an electric motor without any kind of velocity feedback control, it is even possible to stop...

  16. Temporal Dynamics of the Driving Factors of Urban Landscape Change of Addis Ababa During the Past Three Decades.

    Science.gov (United States)

    Zewdie, Meskerem; Worku, Hailu; Bantider, Amare

    2018-01-01

    Mapping and quantifying urban landscape dynamics and the underlying driving factors are crucial for devising appropriate policies, especially in cities of developing countries where the change is rapid. This study analyzed three decades (1984-2014) of land use land cover change of Addis Ababa using Landsat imagery and examined the underlying factors and their temporal dynamics through expert interview using Analytic Hierarchy Process (AHP). Classification results revealed that urban area increased by 50%, while agricultural land and forest decreased by 34 and 16%, respectively. The driving factors operated differently during the pre and post-1991 period. The year 1991 was chosen because it marked government change in the country resulting in policy change. Policy had the highest influence during the pre-1991 period. Land use change in this period was associated with the housing sector as policies and institutional setups were permissive to this sector. Population growth and in-migration were also important factors. Economic factors played significant role in the post-1991 period. The fact that urban land has a market value, the growth of private investment, and the speculated property market were among the economic factors. Policy reforms since 2003 were also influential to the change. Others such as accessibility, demography, and neighborhood factors were a response to economic factors. All the above-mentioned factors had vital role in shaping the urban pattern of the city. These findings can help planners and policymakers to better understand the dynamic relationship of urban land use and the driving factors to better manage the city.

  17. Temporal Dynamics of the Driving Factors of Urban Landscape Change of Addis Ababa During the Past Three Decades

    Science.gov (United States)

    Zewdie, Meskerem; Worku, Hailu; Bantider, Amare

    2018-01-01

    Mapping and quantifying urban landscape dynamics and the underlying driving factors are crucial for devising appropriate policies, especially in cities of developing countries where the change is rapid. This study analyzed three decades (1984-2014) of land use land cover change of Addis Ababa using Landsat imagery and examined the underlying factors and their temporal dynamics through expert interview using Analytic Hierarchy Process (AHP). Classification results revealed that urban area increased by 50%, while agricultural land and forest decreased by 34 and 16%, respectively. The driving factors operated differently during the pre and post-1991 period. The year 1991 was chosen because it marked government change in the country resulting in policy change. Policy had the highest influence during the pre-1991 period. Land use change in this period was associated with the housing sector as policies and institutional setups were permissive to this sector. Population growth and in-migration were also important factors. Economic factors played significant role in the post-1991 period. The fact that urban land has a market value, the growth of private investment, and the speculated property market were among the economic factors. Policy reforms since 2003 were also influential to the change. Others such as accessibility, demography, and neighborhood factors were a response to economic factors. All the above-mentioned factors had vital role in shaping the urban pattern of the city. These findings can help planners and policymakers to better understand the dynamic relationship of urban land use and the driving factors to better manage the city.

  18. Protein activation dynamics in cells and tumor micro arrays assessed by time resolved Förster resonance energy transfer.

    Science.gov (United States)

    Calleja, Véronique; Leboucher, Pierre; Larijani, Banafshé

    2012-01-01

    Analytical time resolved Förster resonance energy transfer (FRET) can be exploited for assessing, in cells and tumor micro arrays, the activation status and dynamics of oncoproteins such as epidermal growth factor receptor (EGFR1) and their downstream effectors such as protein kinase B (PKB) and 3-phosphoinositide-dependent protein kinase 1 (PDK1). The outcome of our research involving the application of quantitative imaging for investigating molecular mechanisms of phosphoinositide-dependant enzymes, such as PKB and PDK1, has resulted in a refined model describing the dynamics and regulation of these two oncoproteins in live cells. Our translational research exploits a quantitative FRET method for establishing the activation status of predictive biomarkers in tumor micro arrays. We developed a two-site FRET assay monitored by automated frequency domain Fluorescence lifetime imaging microscopy (FLIM). As a proof of principle, we tested our methodology by assessing EGFR1 activation status in tumor micro arrays from head and neck patients. Our two-site FRET assay, by high-throughput frequency domain FLIM, has great potential to provide prognostic and perhaps predictive biomarkers. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Static and dynamic characterization of robust superhydrophobic surfaces built from nano-flowers on silicon micro-post arrays

    KAUST Repository

    Chen, Longquan

    2010-09-01

    Superhydrophobic nano-flower surfaces were fabricated using MEMS technology and microwave plasma-enhanced chemical vapor deposition (MPCVD) of carbon nanotubes on silicon micro-post array surfaces. The nano-flower structures can be readily formed within 1-2 min on the micro-post arrays with the spacing ranging from 25 to 30 μm. The petals of the nano-flowers consisted of clusters of multi-wall carbon nanotubes. Patterned nano-flower structures were characterized using various microscopy techniques. After MPCVD, the apparent contact angle (160 ± 0.2°), abbreviated as ACA (defined as the measured angle between the apparent solid surface and the tangent to the liquid-fluid interface), of the nano-flower surfaces increased by 139% compared with that of the silicon micro-post arrays. The measured ACA of the nano-flower surface is consistent with the predicted ACA from a modified Cassie-Baxter equation. A high-speed CCD camera was used to study droplet impact dynamics on various micro/nanostructured surfaces. Both static testing (ACA and sliding angle) and droplet impact dynamics demonstrated that, among seven different micro/nanostructured surfaces, the nano-flower surfaces are the most robust superhydrophobic surfaces. © 2010 IOP Publishing Ltd.

  20. The organization and evolution of the Responder satellite in species of the Drosophila melanogaster group: dynamic evolution of a target of meiotic drive.

    Science.gov (United States)

    Larracuente, Amanda M

    2014-11-25

    Satellite DNA can make up a substantial fraction of eukaryotic genomes and has roles in genome structure and chromosome segregation. The rapid evolution of satellite DNA can contribute to genomic instability and genetic incompatibilities between species. Despite its ubiquity and its contribution to genome evolution, we currently know little about the dynamics of satellite DNA evolution. The Responder (Rsp) satellite DNA family is found in the pericentric heterochromatin of chromosome 2 of Drosophila melanogaster. Rsp is well-known for being the target of Segregation Distorter (SD)- an autosomal meiotic drive system in D. melanogaster. I present an evolutionary genetic analysis of the Rsp family of repeats in D. melanogaster and its closely-related species in the melanogaster group (D. simulans, D. sechellia, D. mauritiana, D. erecta, and D. yakuba) using a combination of available BAC sequences, whole genome shotgun Sanger reads, Illumina short read deep sequencing, and fluorescence in situ hybridization. I show that Rsp repeats have euchromatic locations throughout the D. melanogaster genome, that Rsp arrays show evidence for concerted evolution, and that Rsp repeats exist outside of D. melanogaster, in the melanogaster group. The repeats in these species are considerably diverged at the sequence level compared to D. melanogaster, and have a strikingly different genomic distribution, even between closely-related sister taxa. The genomic organization of the Rsp repeat in the D. melanogaster genome is complex-it exists of large blocks of tandem repeats in the heterochromatin and small blocks of tandem repeats in the euchromatin. My discovery of heterochromatic Rsp-like sequences outside of D. melanogaster suggests that SD evolved after its target satellite and that the evolution of the Rsp satellite family is highly dynamic over a short evolutionary time scale (<240,000 years).

  1. Dynamic Mode Tuning of Ultrasonic Guided Wave Using an Array Transducer

    International Nuclear Information System (INIS)

    Kim, Young H.; Song, Sung J.; Park, Joon S.; Kim, Jae H.; Eom, Heung S.

    2005-01-01

    Ultrasonic guided waves have been widely employed for long range inspection of structures such as plates, rods and pipes. There are numerous modes with different wave velocities, and the appropriate mode selection is one of key techniques in the application of guided waves. In the present work, phase tuning by an array transducer was applied to generate ultrasonic guided waves. For this purpose, 8-channel ultrasonic pulser/receiver and their controller which enables sequential activation of each channels with given time delay were developed. Eight transducers were fabricated in order to generate guided waves by using an array transducer. The selective tuning of wave mode can be achieved by changing the interval between elements of an array transducer

  2. Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator : [research summary].

    Science.gov (United States)

    2013-10-16

    The Maryland State Highway Administration (SHA) uses dynamic message signs : (DMS) for traffic and incident management and for providing travel time information. : Previous research in Maryland has shown that a DMS can be an accurate, effective, and ...

  3. Dynamic simulation of a beta-type Stirling engine with cam-drive mechanism via the combination of the thermodynamic and dynamic models

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chin-Hsiang; Yu, Ying-Ju [Department of Aeronautics and Astronautics, National Cheng Kung University, No. 1, Ta-Shieh Road, Tainan, Taiwan (China)

    2011-02-15

    Dynamic simulation of a beta-type Stirling engine with cam-drive mechanism used in concentrating solar power system has been performed. A dynamic model of the mechanism is developed and then incorporated with the thermodynamic model so as to predict the transient behavior of the engine in the hot-start period. In this study, the engine is started from an initial rotational speed. The torques exerted by the flywheel of the engine at any time instant can be calculated by the dynamic model as long as the gas pressures in the chambers, the mass inertia, the friction force, and the external load have been evaluated. The instantaneous rotation speed of the engine is then determined by integration of the equation of rotational motion with respect to time, which in return affects the instantaneous variations in pressure and other thermodynamic properties of the gas inside the chambers. Therefore, the transient variations in gas properties inside the engine chambers and the dynamic behavior of the engine mechanism should be handled simultaneously via the coupling of the thermodynamic and dynamic models. An extensive parametric study of the effects of different operating and geometrical parameters has been performed, and results regarding the effects of mass moment of inertia of the flywheel, initial rotational speed, initial charged pressure, heat source temperature, phase angle, gap size, displacer length, and piston stroke on the engine transient behavior are investigated. (author)

  4. A general theory for dynamic instability of tube arrays in crossflow

    Science.gov (United States)

    Chen, S. S.

    1987-01-01

    A general theory of fluidelastic instability for a tube array in crossflow is presented. Various techniques to obtain the motion-dependent fluid-force coefficients are discussed and the general instability characteristics are summarized. The theory is also used to evaluate the results of other mathematical models for crossflow-induced instability.

  5. Dynamic and modular gene regulatory networks drive the development of gametogenesis.

    Science.gov (United States)

    Che, Dongxue; Wang, Yang; Bai, Weiyang; Li, Leijie; Liu, Guiyou; Zhang, Liangcai; Zuo, Yongchun; Tao, Shiheng; Hua, Jinlian; Liao, Mingzhi

    2017-07-01

    Gametogenesis is a complex process, which includes mitosis and meiosis and results in the production of ovum and sperm. The development of gametogenesis is dynamic and needs many different genes to work synergistically, but it is lack of global perspective research about this process. In this study, we detected the dynamic process of gametogenesis from the perspective of systems biology based on protein-protein interaction networks (PPINs) and functional analysis. Results showed that gametogenesis genes have strong synergistic effects in PPINs within and between different phases during the development. Addition to the synergistic effects on molecular networks, gametogenesis genes showed functional consistency within and between different phases, which provides the further evidence about the dynamic process during the development of gametogenesis. At last, we detected and provided the core molecular modules of different phases about gametogenesis. The gametogenesis genes and related modules can be obtained from our Web site Gametogenesis Molecule Online (GMO, http://gametsonline.nwsuaflmz.com/index.php), which is freely accessible. GMO may be helpful for the reference and application of these genes and modules in the future identification of key genes about gametogenesis. Summary, this work provided a computational perspective and frame to the analysis of the gametogenesis dynamics and modularity in both human and mouse. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines : A Parameter Study

    NARCIS (Netherlands)

    Jarquin Laguna, A.; Diepeveen, N.F.B.

    2013-01-01

    In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed

  7. What Is It That Drives Dynamics: We Don't Believe in Ghosts, Do We?

    NARCIS (Netherlands)

    Treur, Jan

    2016-01-01

    Dynamics has puzzled researchers since long ago. Among them are Greek philosophers such as Zeno of Elea (about 490-425 BC) and Aristotle (384-322 BC). They pointed at the phenomenon that the world occurs to us in different states at different points in time. However, for the transition from a given

  8. Transients drive the demographic dynamics of plant populations in variable environments

    DEFF Research Database (Denmark)

    McDonald, Jenni L; Stott, Iain; Townley, Stuart

    2016-01-01

    The dynamics of structured plant populations in variable environments can be decomposed into the ‘asymptotic’ growth contributed by vital rates, and ‘transient’ growth caused by deviation from stable stage structure. We apply this framework to a large, global data base of longitudinal studies of ...

  9. Emission enhancement, light extraction and carrier dynamics in InGaAs/GaAs nanowire arrays

    Science.gov (United States)

    Kivisaari, Pyry; Chen, Yang; Anttu, Nicklas

    2018-03-01

    Nanowires (NWs) have the potential for a wide range of new optoelectronic applications. For example, light-emitting diodes that span over the whole visible spectrum are currently being developed from NWs to overcome the well known green gap problem. However, due to their small size, NW devices exhibit special properties that complicate their analysis, characterization, and further development. In this paper, we develop a full optoelectronic simulation tool for NW array light emitters accounting for carrier transport and wave-optical emission enhancement (EE), and we use the model to simulate InGaAs/GaAs NW array light emitters with different geometries and temperatures. Our results show that NW arrays emit light preferentially to certain angles depending on the NW diameter and temperature, encouraging temperature- and angle-resolved measurements of NW array light emission. On the other hand, based on our results both the EE and light extraction efficiency can easily change by at least a factor of two between room temperature and 77 K, complicating the characterization of NW light emitters if conventional methods are used. Finally, simulations accounting for surface recombination emphasize its major effect on the device performance. For example, a surface recombination velocity of 104 cm s-1 reported earlier for bare InGaAs surfaces results in internal quantum efficiencies less than 30% for small-diameter NWs even at the temperature of 30 K. This highlights that core-shell structures or high-quality passivation techniques are eventually needed to achieve efficient NW-based light emitters.

  10. Physical investigation of square cylinder array dynamical response under single-phase cross-flow

    International Nuclear Information System (INIS)

    Longatte, E.; Baj, F.

    2014-01-01

    Fluid structure interaction and flow-induced vibration in square cylinder arrangement under single-phase incompressible laminar cross flow are investigated in the present paper. Dynamic instability governed by damping generation is studied without any consideration about mixing with turbulence effects. Conservative and non-conservative effects are pointed out and dynamical stability limit sensitivity to physical parameters is analyzed. Finally the influence of key physical parameters on fluid solid dynamics interaction is quantified. (authors)

  11. Direct and array observations for near source dynamic strain during large earthquakes

    Science.gov (United States)

    Huang, Bor-Shouh; Huang, Win-Gee; Lin, Chin-Jen

    2017-04-01

    The seismic ground motions from the 1999 Chi-Chi Taiwan earthquake (ML=7.6) and it large aftershocks were well recorded by a dense seismic array (named the Hualien Large Scale Seismic Test, HLSST) in near source distances. The HLSST site was situated in the the site of Hualien Veteran's Marble Plant. It included one scaled down reinforced concrete cylindrical containment model (1/4 scale). The radius of this cylindrical model is of about 5.4 meters. The instrumentation of this program consisted of forty-two stations. They were fifteen surface accelerometers, twelve downhole accelerometers and fifteen containment structure response accelerometers. The fifteen free-field stations were installed at three arms. The twelve downhole accelerometers were distributed beneath this array. One delta ground strain gauge was commonly installed in this site and well recorded those events. In this study, we inferred ground strains by a least-squares fit of array translational ground-motion data using the method proposed by Spudich et al. (1995) and Spudich and Fletcher (2008) and the same as from strain gauge records. We analyzed the main shock and November 1 offshore event for ground rotations and the same as ground strains. We will discuss the relationship of observed spatial ground deformations with source rupture processes and onsite ground translations. We hope to discuss its implications also about earthquake engineering applications.

  12. High-Density Microfluidic Particle-Cluster-Array Device for Parallel and Dynamic Study of Interaction between Engineered Particles.

    Science.gov (United States)

    Kim, Hojin; Lee, Sanghyun; Lee, Wonhyung; Kim, Joonwon

    2017-08-01

    A high-density and high-performance microfluidic particle-cluster-array device utilizing a novel hydrodynamically tunable pneumatic valve (HTPV) is reported for parallel and dynamic monitoring of the interactions taking place in particle clusters. The key concept involves passive operation of the HTPV through elastic deformation of a thin membrane using only the hydrodynamic force inherent in microchannel flows. This unique feature allows the discrete and high-density (≈30 HTPVs mm -2 ) arrangement of numerous HTPVs in a microfluidic channel without any pneumatic connection. In addition, the HTPV achieves high-performance clustering (≈92%) of three different particles in an array format through the optimization of key design and operating parameters. Finally, a contamination-free, parallel, and dynamic biochemical analysis strategy is proposed, which employs a simple one-inlet-one-outlet device operated by the effective combination of several techniques, including particle clustering, the interactions between engineered particles, two-phase partitioning and dehydration control of aqueous plugs, and shape/color-based particle identification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Polyphilic Interactions as Structural Driving Force Investigated by Molecular Dynamics Simulation (Project 7

    Directory of Open Access Journals (Sweden)

    Christopher Peschel

    2017-09-01

    Full Text Available We investigated the effect of fluorinated molecules on dipalmitoylphosphatidylcholine (DPPC bilayers by force-field molecular dynamics simulations. In the first step, we developed all-atom force-field parameters for additive molecules in membranes to enable an accurate description of those systems. On the basis of this force field, we performed extensive simulations of various bilayer systems containing different additives. The additive molecules were chosen to be of different size and shape, and they included small molecules such as perfluorinated alcohols, but also more complex molecules. From these simulations, we investigated the structural and dynamic effects of the additives on the membrane properties, as well as the behavior of the additive molecules themselves. Our results are in good agreement with other theoretical and experimental studies, and they contribute to a microscopic understanding of interactions, which might be used to specifically tune membrane properties by additives in the future.

  14. Environmental transmission of Mycobacterium ulcerans drives dynamics of Buruli ulcer in endemic regions of Cameroon

    Science.gov (United States)

    Garchitorena, Andrés; Ngonghala, Calistus N.; Texier, Gaëtan; Landier, Jordi; Eyangoh, Sara; Bonds, Matthew H.; Guégan, Jean-François; Roche, Benjamin

    2015-12-01

    Buruli Ulcer is a devastating skin disease caused by the pathogen Mycobacterium ulcerans. Emergence and distribution of Buruli ulcer cases is clearly linked to aquatic ecosystems, but the specific route of transmission of M. ulcerans to humans remains unclear. Relying on the most detailed field data in space and time on M. ulcerans and Buruli ulcer available today, we assess the relative contribution of two potential transmission routes -environmental and water bug transmission- to the dynamics of Buruli ulcer in two endemic regions of Cameroon. The temporal dynamics of Buruli ulcer incidence are explained by estimating rates of different routes of transmission in mathematical models. Independently, we also estimate statistical models of the different transmission pathways on the spatial distribution of Buruli ulcer. The results of these two independent approaches are corroborative and suggest that environmental transmission pathways explain the temporal and spatial patterns of Buruli ulcer in our endemic areas better than the water bug transmission.

  15. Spin-Orbit Coupling Drives Femtosecond Nonadiabatic Dynamics in a Transition Metal Compound.

    Science.gov (United States)

    Carbery, William P; Verma, Archana; Turner, Daniel B

    2017-03-16

    Transient absorption measurements conducted using broadband, 6 fs laser pulses reveal unexpected femtosecond dynamics in the [IrBr 6 ] 2- model system. Vibrational spectra and the X-ray crystal structure indicate that these dynamics are not induced by a Jahn-Teller distortion, a type of conical intersection typically associated with the spectral features of transition metal compounds. Two-dimensional electronic spectra of [IrBr 6 ] 2- contain 23 cross peaks, which necessarily arise from spin-orbit coupling. Real-valued 2D spectra support a spectroscopic basis where strong nonadiabatic coupling, ascribed to multiple conical intersections, mediates rapid energy relaxation to the lowest-energy excited state. Subsequent analysis gives rise to a more generalized description of a conical intersection as a degeneracy between two adiabatic states having the same total angular momentum.

  16. Seasonal Differences in Extinction and Colonization Drive Occupancy Dynamics of an Imperilled Amphibian

    Science.gov (United States)

    Randall, Lea A.; Smith, Des H. V.; Jones, Breana L.; Prescott, David R. C.; Moehrenschlager, Axel

    2015-01-01

    A detailed understanding of the population dynamics of many amphibian species is lacking despite concerns about declining amphibian biodiversity and abundance. This paper explores temporal patterns of occupancy and underlying extinction and colonization dynamics in a regionally imperiled amphibian species, the Northern leopard frog (Lithobates pipiens) in Alberta. Our study contributes to elucidating regional occupancy dynamics at northern latitudes, where climate extremes likely have a profound effect on seasonal occupancy. The primary advantage of our study is its wide geographic scale (60,000 km2) and the use of repeat visual surveys each spring and summer from 2009–2013. We find that occupancy varied more dramatically between seasons than years, with low spring and higher summer occupancy. Between spring and summer, colonization was high and extinction low; inversely, colonization was low and extinction high over the winter. The dynamics of extinction and colonization are complex, making conservation management challenging. Our results reveal that Northern leopard frog occupancy was constant over the last five years and thus there is no evidence of decline or recovery within our study area. Changes to equilibrium occupancy are most sensitive to increasing colonization in the spring or declining extinction in the summer. Therefore, conservation and management efforts should target actions that are likely to increase spring colonization; this could be achieved through translocations or improving the quality or access to breeding habitat. Because summer occupancy is already high, it may be difficult to improve further. Nevertheless, summer extinction could be reduced by predator control, increasing water quality or hydroperiod of wetlands, or increasing the quality or quantity of summer habitat. PMID:25993256

  17. Piecewise nonlinear dynamic characteristics study of the control rod drive mechanism

    International Nuclear Information System (INIS)

    Shen Xiaoyao; Wang Feng

    2011-01-01

    Piecewise nonlinear dynamics of the control rod mechanism (CRDM), one of the critical components in PWR nuclear power plants, are studied for its lifting process in this paper. Firstly, equations of the electric circuit and the magnetic circuit are set up. Then based on the dynamic lifting process analysis of CRDM, its motion procedure is divided into three stages, and the coupled magnetic-electric-mechanical equation for each stage is derived. By combining the analytical solution method and the numerical simulation method, the piecewise nonlinear governing equations are solved. Finally, parameters which can illustrate the dynamic characteristics of CRDM, such as the magnetic force, the coil current, the armature displacement, the armature velocity and the acceleration are obtained and corresponding curves with the time are drawn and analyzed. The analysis results are confirmed by the test which proves the validity of our method. Work in this paper can be used for design and analysis as well as the site fault diagnosis of CRDM. (author)

  18. Attosecond transient-absorption dynamics of xenon core-excited states in a strong driving field

    Science.gov (United States)

    Kobayashi, Yuki; Timmers, Henry; Sabbar, Mazyar; Leone, Stephen R.; Neumark, Daniel M.

    2017-03-01

    We present attosecond transient-absorption experiments on xenon 4 d-16 p core-level states resonantly driven by intense (1.6 ×1014W/cm 2 ) few-cycle near-infrared laser pulses. In this strongly driven regime, broad induced absorption features with half-cycle (1.3-fs) delay-dependent modulation are observed over the range of 58-65 eV, predicted as a signature of the breakdown of the rotating-wave approximation in strong-field driving of Autler-Townes splitting [A. N. Pfeiffer and S. R. Leone, Phys. Rev. A 85, 053422 (2012), 10.1103/PhysRevA.85.053422]. Relevant atomic states are identified by a numerical model involving three electronic states, and the mechanism behind the broad induced absorption is discussed in the Floquet formalism. These results demonstrate that a near-infrared field well into the tunneling regime can still control the optical properties of an atomic system over a several-electron-volt spectral range and with attosecond precision.

  19. Climate, invasive species and land use drive population dynamics of a cold-water specialist

    Science.gov (United States)

    Kovach, Ryan P.; Al-Chokhachy, Robert K.; Whited, Diane C.; Schmetterling, David A.; Dux, Andrew M; Muhlfeld, Clint C.

    2017-01-01

    Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population dynamics in the context of other existing stressors.We used long-term data from 92 populations of bull trout Salvelinus confluentus – one of North America's most cold-adapted fishes – to quantify additive and interactive effects of climate, invasive species and land use on population dynamics (abundance, variability and growth rate).Populations were generally depressed, more variable and declining where spawning and rearing stream habitat was limited, invasive species and land use were prevalent and stream temperatures were highest. Increasing stream temperature acted additively and independently, whereas land use and invasive species had additive and interactive effects (i.e. the impact of one stressor depended on exposure to the other stressor).Most (58%–78%) of the explained variation in population dynamics was attributed to the presence of invasive species, differences in life history and management actions in foraging habitats in rivers, lakes and reservoirs. Although invasive fishes had strong negative effects on populations in foraging habitats, proactive control programmes appeared to effectively temper their negative impact.Synthesis and applications. Long-term demographic data emphasize that climate warming will exacerbate imperilment of cold-water specialists like bull trout, yet other stressors – especially invasive fishes – are immediate threats that can be addressed by proactive management actions. Therefore, climate-adaptation strategies for freshwater biodiversity should consider existing abiotic and biotic stressors, some of which provide potential and realized opportunity for conservation

  20. Numerical computation of soliton dynamics for NLS equations in a driving potential

    Directory of Open Access Journals (Sweden)

    Marco Caliari

    2010-06-01

    Full Text Available We provide numerical computations for the soliton dynamics of the nonlinear Schrodinger equation with an external potential. After computing the ground state solution r of a related elliptic equation we show that, in the semi-classical regime, the center of mass of the solution with initial datum built upon r is driven by the solution to $ddot x=- abla V(x$. Finally, we provide examples and analyze the numerical errors in the two dimensional case when V is a harmonic potential.

  1. Constraints on the Dynamical Environments of Supermassive Black-Hole Binaries Using Pulsar-Timing Arrays.

    Science.gov (United States)

    Taylor, Stephen R; Simon, Joseph; Sampson, Laura

    2017-05-05

    We introduce a technique for gravitational-wave analysis, where Gaussian process regression is used to emulate the strain spectrum of a stochastic background by training on population-synthesis simulations. This leads to direct Bayesian inference on astrophysical parameters. For pulsar timing arrays specifically, we interpolate over the parameter space of supermassive black-hole binary environments, including three-body stellar scattering, and evolving orbital eccentricity. We illustrate our approach on mock data, and assess the prospects for inference with data similar to the NANOGrav 9-yr data release.

  2. Dynamic Towed Array Models and State Estimation for Underwater Target Tracking

    Science.gov (United States)

    2013-09-01

    speed of sound for the conducting medium. In the case of sea water, the speed of sound is not a constant but varies with conditions. Therefore, when...Mean BO-EKF Tgt Position Est. Receiver Trajectory 62 a multitude of conditions that are regularly seen at sea . Examples where SNR could increase as...19, 2013. [6] S. G. Lemon , “Towed-array history, 1917–2003,” IEEE J. of Ocean. Eng., vol. 29, pp. 365–373, Apr. 2004. [7] M. S. Cohen and R. V

  3. Effect of Nondissipative Terms in Dynamical Phases of Vortex Matter in a Periodic Pinning Array

    Science.gov (United States)

    Arovas, Daniel

    2000-03-01

    The zero temperature dynamical phases of driven vortex lattices [1] are reconsidered, introducing a nondynamical term (proportional to the sine of the Hall angle) into the equations of motion. While such a term does not affect the static thermodynamic phases of the system, it may have a profound effect on the dynamics. We find that finite Hall angle tends to reduce the effect of pinning in certain dynamical phases. [1] C. Reichhardt, C. J. Olson, and F. Nori, Phys. Rev. B 58, 6534, 1998.

  4. Snowmelt Induced Hydrologic Perturbations Drive Dynamic Microbiological and Geochemical Behaviors across a Shallow Riparian Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Danczak, Robert E.; Yabusaki, Steven B.; Williams, Kenneth H.; Fang, Yilin; Hobson, Chad; Wilkins, Michael J.

    2016-05-11

    Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments. Frontiers in Earth Science Journal Impact & Description - ResearchGate - Impact Rankings ( 2015 and 2016 ). Available from: https://www.researchgate.net/journal/2296-6463_Frontiers_in_Earth_Science [accessed Jul 25, 2016].

  5. Internal exposure dynamics drive the Adverse Outcome Pathways of synthetic glucocorticoids in fish

    Science.gov (United States)

    Margiotta-Casaluci, Luigi; Owen, Stewart F.; Huerta, Belinda; Rodríguez-Mozaz, Sara; Kugathas, Subramanian; Barceló, Damià; Rand-Weaver, Mariann; Sumpter, John P.

    2016-02-01

    The Adverse Outcome Pathway (AOP) framework represents a valuable conceptual tool to systematically integrate existing toxicological knowledge from a mechanistic perspective to facilitate predictions of chemical-induced effects across species. However, its application for decision-making requires the transition from qualitative to quantitative AOP (qAOP). Here we used a fish model and the synthetic glucocorticoid beclomethasone dipropionate (BDP) to investigate the role of chemical-specific properties, pharmacokinetics, and internal exposure dynamics in the development of qAOPs. We generated a qAOP network based on drug plasma concentrations and focused on immunodepression, skin androgenisation, disruption of gluconeogenesis and reproductive performance. We showed that internal exposure dynamics and chemical-specific properties influence the development of qAOPs and their predictive power. Comparing the effects of two different glucocorticoids, we highlight how relatively similar in vitro hazard-based indicators can lead to different in vivo risk. This discrepancy can be predicted by their different uptake potential, pharmacokinetic (PK) and pharmacodynamic (PD) profiles. We recommend that the development phase of qAOPs should include the application of species-species uptake and physiologically-based PK/PD models. This integration will significantly enhance the predictive power, enabling a more accurate assessment of the risk and the reliable transferability of qAOPs across chemicals.

  6. A dynamical approach in exploring the unknown mass in the Solar system using pulsar timing arrays

    Science.gov (United States)

    Guo, Y. J.; Lee, K. J.; Caballero, R. N.

    2018-04-01

    The error in the Solar system ephemeris will lead to dipolar correlations in the residuals of pulsar timing array for widely separated pulsars. In this paper, we utilize such correlated signals, and construct a Bayesian data-analysis framework to detect the unknown mass in the Solar system and to measure the orbital parameters. The algorithm is designed to calculate the waveform of the induced pulsar-timing residuals due to the unmodelled objects following the Keplerian orbits in the Solar system. The algorithm incorporates a Bayesian-analysis suit used to simultaneously analyse the pulsar-timing data of multiple pulsars to search for coherent waveforms, evaluate the detection significance of unknown objects, and to measure their parameters. When the object is not detectable, our algorithm can be used to place upper limits on the mass. The algorithm is verified using simulated data sets, and cross-checked with analytical calculations. We also investigate the capability of future pulsar-timing-array experiments in detecting the unknown objects. We expect that the future pulsar-timing data can limit the unknown massive objects in the Solar system to be lighter than 10-11-10-12 M⊙, or measure the mass of Jovian system to a fractional precision of 10-8-10-9.

  7. Probing the assembly history and dynamical evolution of massive black hole binaries with pulsar timing arrays

    Science.gov (United States)

    Chen, Siyuan; Middleton, Hannah; Sesana, Alberto; Del Pozzo, Walter; Vecchio, Alberto

    2017-06-01

    We consider the inverse problem in pulsar timing array (PTA) analysis, investigating what astrophysical information about the underlying massive black hole binary (MBHB) population can be recovered from the detection of a stochastic gravitational wave background (GWB). We employ a physically motivated model that connects the GWB spectrum to a series of parameters describing the underlying redshift evolution of the MBHB mass function and to the typical eccentricity they acquire while interacting with the dense environment of post-merger galactic nuclei. This allows the folding in of information about the spectral shape of the GWB into the analysis. The priors on the model parameters are assumed to be uninformative and consistent with the current lack of secure observations of sub-parsec MBHBs. We explore the implications of current upper limits and of future detections with a variety of PTA configurations. We confirm our previous finding that current upper limits can only place an upper bound on the overall MBHB merger rate. Depending on the properties of the array, future detections can also constrain several MBHB population models at different degrees of fidelity. In particular, a simultaneous detection of a steepening of the spectrum at high frequency and a bending at low frequency will place strong constraints on both the MBHB mass function and on the typical eccentricity of inspiralling MBHBs, providing insights into MBHB astrophysics unlikely to be achievable by any other means.

  8. Global Rice Watch: Spatial-temporal dynamics, driving factors, and impacts of paddy rice agriculture in the world

    Science.gov (United States)

    Xiao, X.; Dong, J.; Zhang, G.; Xin, F.; Li, X.

    2017-12-01

    Paddy rice croplands account for more than 12% of the global cropland areas, and provide food to feed more than 50% of the world population. Spatial patterns and temporal dynamics of paddy rice croplands have changed remarkably in the past decades, driven by growing human population and their changing diet structure, land use (e.g., urbanization, industrialization), climate, markets, and technologies. In this presentation, we will provide a comprehensive review of our current knowledge on (1) the spatial patterns and temporal dynamics of paddy rice croplands from agricultural statistics data and remote sensing approaches; (2) major driving factors for the observed changes in paddy rice areas, including social, economic, climate, land use, markets, crop breeding technology, and farming technology; and (3) major impacts on atmospheric methane concentration, land surface temperature, water resources and use, and so on. We will highlight the results from a few case studies in China and monsoon Asia. We will also call for a global synthesis analysis of paddy rice agriculture, and invite researchers to join the effort to write and edit a book that provides comprehensive and updated knowledge on paddy rice agriculture.

  9. Modeling soil organic carbon dynamics and their driving factors in the main global cereal cropping systems

    Science.gov (United States)

    Wang, Guocheng; Zhang, Wen; Sun, Wenjuan; Li, Tingting; Han, Pengfei

    2017-10-01

    Changes in the soil organic carbon (SOC) stock are determined by the balance between the carbon input from organic materials and the output from the decomposition of soil C. The fate of SOC in cropland soils plays a significant role in both sustainable agricultural production and climate change mitigation. The spatiotemporal changes of soil organic carbon in croplands in response to different carbon (C) input management and environmental conditions across the main global cereal systems were studied using a modeling approach. We also identified the key variables that drive SOC changes at a high spatial resolution (0.1° × 0.1°) and over a long timescale (54 years from 1961 to 2014). A widely used soil C turnover model (RothC) and state-of-the-art databases of soil and climate variables were used in the present study. The model simulations suggested that, on a global average, the cropland SOC density increased at annual rates of 0.22, 0.45 and 0.69 Mg C ha-1 yr-1 under crop residue retention rates of 30, 60 and 90 %, respectively. Increasing the quantity of C input could enhance soil C sequestration or reduce the rate of soil C loss, depending largely on the local soil and climate conditions. Spatially, under a specific crop residue retention rate, relatively higher soil C sinks were found across the central parts of the USA, western Europe, and the northern regions of China. Relatively smaller soil C sinks occurred in the high-latitude regions of both the Northern and Southern hemispheres, and SOC decreased across the equatorial zones of Asia, Africa and America. We found that SOC change was significantly influenced by the crop residue retention rate (linearly positive) and the edaphic variable of initial SOC content (linearly negative). Temperature had weak negative effects, and precipitation had significantly negative impacts on SOC changes. The results can help guide carbon input management practices to effectively mitigate climate change through soil C

  10. Modeling soil organic carbon dynamics and their driving factors in the main global cereal cropping systems

    Directory of Open Access Journals (Sweden)

    G. Wang

    2017-10-01

    Full Text Available Changes in the soil organic carbon (SOC stock are determined by the balance between the carbon input from organic materials and the output from the decomposition of soil C. The fate of SOC in cropland soils plays a significant role in both sustainable agricultural production and climate change mitigation. The spatiotemporal changes of soil organic carbon in croplands in response to different carbon (C input management and environmental conditions across the main global cereal systems were studied using a modeling approach. We also identified the key variables that drive SOC changes at a high spatial resolution (0.1°  ×  0.1° and over a long timescale (54 years from 1961 to 2014. A widely used soil C turnover model (RothC and state-of-the-art databases of soil and climate variables were used in the present study. The model simulations suggested that, on a global average, the cropland SOC density increased at annual rates of 0.22, 0.45 and 0.69 Mg C ha−1 yr−1 under crop residue retention rates of 30, 60 and 90 %, respectively. Increasing the quantity of C input could enhance soil C sequestration or reduce the rate of soil C loss, depending largely on the local soil and climate conditions. Spatially, under a specific crop residue retention rate, relatively higher soil C sinks were found across the central parts of the USA, western Europe, and the northern regions of China. Relatively smaller soil C sinks occurred in the high-latitude regions of both the Northern and Southern hemispheres, and SOC decreased across the equatorial zones of Asia, Africa and America. We found that SOC change was significantly influenced by the crop residue retention rate (linearly positive and the edaphic variable of initial SOC content (linearly negative. Temperature had weak negative effects, and precipitation had significantly negative impacts on SOC changes. The results can help guide carbon input management practices to

  11. Understanding the dynamic interactions driving Zambian health centre performance: a case-based health systems analysis

    Science.gov (United States)

    Topp, Stephanie M; Chipukuma, Julien M; Hanefeld, Johanna

    2015-01-01

    Background Despite being central to achieving improved population health outcomes, primary health centres in low- and middle-income settings continue to underperform. Little research exists to adequately explain how and why this is the case. This study aimed to test the relevance and usefulness of an adapted conceptual framework for improving our understanding of the mechanisms and causal pathways influencing primary health centre performance. Methods A theory-driven, case-study approach was adopted. Four Zambian health centres were purposefully selected with case data including health-care worker interviews (n = 60); patient interviews (n = 180); direct observation of facility operations (2 weeks/centre) and key informant interviews (n = 14). Data were analysed to understand how the performance of each site was influenced by the dynamic interactions between system ‘hardware’ and ‘software’ acting on mechanisms of accountability. Findings Structural constraints including limited resources created challenging service environments in which work overload and stockouts were common. Health workers’ frustration with such conditions interacted with dissatisfaction with salary levels eroding service values and acting as a catalyst for different forms of absenteeism. Such behaviours exacerbated patient–provider ratios and increased the frequency of clinical and administrative shortcuts. Weak health information systems and lack of performance data undermined providers’ answerability to their employer and clients, and a lack of effective sanctions undermined supervisors’ ability to hold providers accountable for these transgressions. Weak answerability and enforceability contributed to a culture of impunity that masked and condoned weak service performance in all four sites. Conclusions Health centre performance is influenced by mechanisms of accountability, which are in turn shaped by dynamic interactions between system hardware and system software. Our

  12. Fundamentals of electrical drives

    CERN Document Server

    Veltman, André; De Doncker, Rik W

    2007-01-01

    Provides a comprehensive introduction to various aspects of electrical drive systems. This volume provides a presentation of dynamic generic models that cover all major electrical machine types and modulation/control components of a drive as well as dynamic and steady state analysis of transformers and electrical machines.

  13. Long-term dynamics in land resource use and the driving forces in the Beressa watershed, highlands of Ethiopia.

    Science.gov (United States)

    Amsalu, Aklilu; Stroosnijder, Leo; de Graaff, Jan

    2007-06-01

    Land degradation in the Ethiopian highlands is considered to be one of the major problems threatening agricultural development and food security in the country. However, knowledge about the forces driving the long-term dynamics in land resources use is limited. This research integrates biophysical information with socio-economic processes and policy changes to examine the dynamics of land resource use and farmers' livelihoods in the Beressa watershed for over 40 years during the second half of the 20th century. It was found that there have been substantial dynamics in land resource use in the area. The natural vegetation cover has been extensively cleared, although most of the cleared areas have since been replaced with plantations. Grazing land has expanded remarkably at the expense of cropland and bare land. However, the expansion of cropland was minimal over the 43-year period despite a quadrupling of the population density. Yields have not increased to compensate for the reduction in per capita cropland, and the soil quality appears to be not that good. Though the farmers perceived it otherwise, the long-term rainfall pattern has improved. In response to soil degradation, water shortage, socio-economic and policy changes, farmers have tended to gradually change from annual cropping to tree planting and livestock production to cope with the problems of soil degradation, water scarcity and smaller farms. Income diversification through the sale of wood and cattle dung is becoming a major livelihood strategy. Apparently, however, little attention has been paid to investments in soil and water conservation (SWC) and local soil fertility amendments. In particular, increased erosion and related high nutrient losses in sediments, as well as the removal of potentially available soil nutrients through the sale of manure threatens to damage agricultural sustainability in the area.

  14. In situ single-atom array synthesis using dynamic holographic optical tweezers

    Science.gov (United States)

    Kim, Hyosub; Lee, Woojun; Lee, Han-gyeol; Jo, Hanlae; Song, Yunheung; Ahn, Jaewook

    2016-01-01

    Establishing a reliable method to form scalable neutral-atom platforms is an essential cornerstone for quantum computation, quantum simulation and quantum many-body physics. Here we demonstrate a real-time transport of single atoms using holographic microtraps controlled by a liquid-crystal spatial light modulator. For this, an analytical design approach to flicker-free microtrap movement is devised and cold rubidium atoms are simultaneously rearranged with 2N motional degrees of freedom, representing unprecedented space controllability. We also accomplish an in situ feedback control for single-atom rearrangements with the high success rate of 99% for up to 10 μm translation. We hope this proof-of-principle demonstration of high-fidelity atom-array preparations will be useful for deterministic loading of N single atoms, especially on arbitrary lattice locations, and also for real-time qubit shuttling in high-dimensional quantum computing architectures. PMID:27796372

  15. Experimental investigation of unsteady fluid dynamic forces acting on tube array

    International Nuclear Information System (INIS)

    Tanaka, Hiroki; Takahara, Shigeru; Tanaka, Mitsutoshi

    1981-01-01

    It is well-known that the cylinder bundle vibrates in cross flow. Many studies of the vibration have been made, and it has been clarified that the vibration is caused by fluid-elastic vibration coupling to neighboring cylinders. The theory given in this paper considers unsteady fluid dynamic forces to be composed of inertia forces due to added mass of fluid, damping forces of fluid which are in phase to cylinder vibrating velocity, and stiffness forces which are proportional to cylinder displacements. Furthermore, taking account of the influences of neighboring cylinder vibrations, ten kinds of unsteady fluid dynamic forces are considered to act on a cylinder in cylinder bundles. Equations of motion of cylinders were deduced and the critical velocities were calculated with the measured unsteady fluid dynamic forces. Critical velocity tests were also conducted with cylinders which were supported with elastic spars. The calculated critical velocities coincided well with the test results. (author)

  16. Synoptic-scale analysis of mechanisms driving surface chlorophyll dynamics in the North Atlantic

    Directory of Open Access Journals (Sweden)

    A. S. A. Ferreira

    2015-06-01

    Full Text Available Several hypotheses have been proposed for the onset of the spring phytoplankton bloom in the North Atlantic. Our main objective is to examine which bottom-up processes can best predict the annual increase in surface phytoplankton concentration in the North Atlantic by applying novel phenology algorithms to ocean colour data. We construct indicator fields and time series which, in various combinations, provide models consistent with the principle dynamics previously proposed. Using a multimodel inference approach, we investigate the evidence supporting these models and how it varies in space. We show that, in terms of bottom-up processes alone, there is a dominant physical mechanism, namely mixed-layer shoaling, that best predicts the interannual variation in the initial increase in surface chlorophyll across large sectors of the North Atlantic. We further show that different regions are governed by different physical phenomena and that wind-driven mixing is a common component, with either heat flux or light as triggers. We believe these findings to be relevant to the ongoing discussion on North Atlantic bloom onset.

  17. Dynamics of Dirac strings and monopolelike excitations in chiral magnets under a current drive

    Science.gov (United States)

    Lin, Shi-Zeng; Saxena, Avadh

    2016-02-01

    Skyrmion lines in metallic chiral magnets carry an emergent magnetic field experienced by the conduction electrons. The inflow and outflow of this field across a closed surface is not necessarily equal, thus it allows for the existence of emergent monopoles. One example is a segment of skyrmion line inside a crystal, where a monopole and antimonopole pair is connected by the emergent magnetic flux line. This is a realization of Dirac stringlike excitations. Here we study the dynamics of monopoles in chiral magnets under an electric current. We show that in the process of creation of skyrmion lines, skyrmion line segments are first created via the proliferation of monopoles and antimonopoles. Then these line segments join and span the whole system through the annihilation of monopoles. The skyrmion lines are destroyed via the proliferation of monopoles and antimonopoles at high currents, resulting in a chiral liquid phase. We also propose to create the monopoles in a controlled way by applying an inhomogeneous current to a crystal. Remarkably, an electric field component in the magnetic field direction proportional to the current squared in the low current region is induced by the motion of distorted skyrmion lines, in addition to the Hall and longitudinal voltage. The existence of monopoles can be inferred from transport or imaging measurements.

  18. Fluvial dynamics of the lower Guadalete River in W-Andalucía (Spain) and decisive driving forces

    Science.gov (United States)

    Wolf, Daniel; Faust, Dominik

    2013-04-01

    This study aims to work out a solid stratigraphy for the Guadalete River in W-Andalucía with focus on late Pleistocene and Holocene fluvial dynamics. We studied 14 profile exposures and 13 percussion drillings by using geomorphologic, sedimentologic and pedogenetic approaches. Supported by ample physical and chemical soil analyses and dating of 34 radiocarbon samples, we were able to reconstruct floodplain development over the last 14 ka. The valley of the lower Guadalete River shows a fluvial architecture that is complex and inconsistent along specific river sections. According to stratigraphic findings, the lower reach of the Guadalete River can be divided into two sedimentary areas. These are characterized by a highly dynamic alternation of sedimentation and erosion, with Holocene terrace formation in the upper downstream section and more calm conditions with sediment preservation and the built-up of continuous sequences in the lower one. Stratigraphic records in combination with a disturbed longitudinal profile revealed that fluvial dynamics responded to various driving forces in late Pleistocene and Holocene times. Sea-level changes have been a determining factor on river dynamics, notably during the late Pleistocene and until the early Holocene, when phases of sea-level fall resulted in strong river incision and clearing-out of floodplain sediments. In the course of a rapid sea-level rise until the early to mid-Holocene, other parameters started to play a determining role, as fluvial dynamics became more and more the expression of environmental conditions in terms of stability and instability of the landscape. As the study area has to be characterized as tectonically very active, the magnitude of fluvial processes, such as river incision was furthermore influenced by small-scale tectonic uplift or subsidence. Periods of floodplain sedimentation (before 9.2, after 8.0, at 4.6 to 4.3, at 2.0, 0.9 and 0.4 ka cal BP) are reflective for unstable landscape

  19. Driving forces behind the increasing cardiovascular treatment intensity.A dynamic epidemiologic model of trends in Danish cardiovascular drug utilization.

    DEFF Research Database (Denmark)

    Kildemoes, Helle Wallach; Andersen, Morten

    -state (untreated, treated, dead) semi-Markov model to analyse the dynamics of drug use. Transitions were from untreated to treated (incidence), the reverse (discontinuation), and from either untreated or treated to dead. Stratified by sex and age categories, prevalence trends of "growth driving" drug categories...

  20. Point vortex modelling of the wake dynamics behind asymmetric vortex generator arrays

    NARCIS (Netherlands)

    Baldacchino, D.; Simao Ferreira, C.; Ragni, D.; van Bussel, G.J.W.

    2016-01-01

    In this work, we present a simple inviscid point vortex model to study the dynamics of asymmetric vortex rows, as might appear behind misaligned vortex generator vanes. Starting from the existing solution of the in_nite vortex cascade, a numerical model of four base-vortices is chosen to represent

  1. Control strategies for DC motors driving rotor dynamic systems through resonance

    Science.gov (United States)

    Bisoi, Alfa; Samantaray, A. K.; Bhattacharyya, Ranjan

    2017-12-01

    Rotor dynamic systems require considerably higher power/torque to accelerate through the structural resonance. However, most sources of mechanical power are non-ideal, i.e., they can only provide a limited amount of power. If there is insufficient power to overcome the resonance then the rotor speed may get caught at resonance and the persistent high vibrations can damage the machine. Various proposed solutions to this problem deal with modifications to the mechanical structure and active/semi-active control of structural parameters. This article proposes modification to the prime mover so that peak available power is delivered exactly at the structural resonance frequency. The limited power/non-ideal prime mover considered in this article is a direct current (DC) motor and the structural resonance happens due to forcing from an eccentric rotor disk and vibrations of a flexible weakly damped foundation. Various control strategies to modify the torque-speed characteristics of permanent magnet, shunt and series wound DC motors to promote escape through resonance are considered. Also, the characteristic curves for rotor/motor speed versus the DC supply voltage are obtained for the considered DC motor types from which the unattainable steady angular speeds and the speed jumps due to Sommerfeld effect are computed. Transient simulations are performed using bond graph models for this multi-energy domain (here, electro-mechanical) system. It is shown that a switched control permitting to switch between shunt and series DC motor configurations gives better regulation over the power delivery at the resonant frequency as well as super-critical operating speeds in the neighborhood of structural resonance.

  2. how social structure drives the population dynamics of the common vampire bat (Desmodus rotundus, Phyllostomidae)?

    Science.gov (United States)

    Huguin, Maïlis; Arechiga-Ceballos, Nidia; Delaval, Marguerite; Guidez, Amandine; Jorge de Castro, Isaï; Lacoste, Vincent; Salmier, Arielle; Aguilar Setien, Alvaro; Silva, Claudia Regina; Lavergne, Anne; de Thoisy, Benoit

    2017-12-08

    Social systems are major drivers of population structure and gene flow, with important effects on dynamics and dispersal of associated populations of parasites. Among bats, the common vampire bat (Desmodus rotundus) has likely one of the most complex social structure. Using autosomal and mitochondrial markers on vampires from Mexico, French Guiana and North Brazil, from both roosting and foraging areas, we observed an isolation by distance at the wider scale and lower but significant differentiation between closer populations (populations had a low level of relatedness and showed deviations from Hardy-Weinberg equilibrium and a low but significant inbreeding coefficient. The associated heterozygote deficiency was likely related to a Wahlund effect and to cryptic structures, reflecting social groups living in syntopy, both in roosting and foraging areas, with only limited admixture. Discrepancy between mitochondrial and nuclear markers suggests female philopatry and higher dispersal rates in males, associated with peripheral positions in the groups. Vampires are also the main neotropical reservoir for rabies virus, one of the main lethal pathogens for humans. Female social behaviors and trophallaxis may favor a rapid spread of virus to related and unrelated offspring and females. The high dispersal capacity of males may explain the wider circulation of viruses and the inefficacy of bat population controls. In such opportunistic species, gene connectivity should be considered for decision making. Strategies such as culling could induce immigration of bats from neighboring colonies to fill vacant roosts and feeding areas, associated with the dispersal of viral strains. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. A new general dynamic model predicting radionuclide concentrations and fluxes in coastal areas from readily accessible driving variables

    International Nuclear Information System (INIS)

    Haakanson, Lars

    2004-01-01

    This paper presents a general, process-based dynamic model for coastal areas for radionuclides (metals, organics and nutrients) from both single pulse fallout and continuous deposition. The model gives radionuclide concentrations in water (total, dissolved and particulate phases and concentrations in sediments and fish) for entire defined coastal areas. The model gives monthly variations. It accounts for inflow from tributaries, direct fallout to the coastal area, internal fluxes (sedimentation, resuspension, diffusion, burial, mixing and biouptake and retention in fish) and fluxes to and from the sea outside the defined coastal area and/or adjacent coastal areas. The fluxes of water and substances between the sea and the coastal area are differentiated into three categories of coast types: (i) areas where the water exchange is regulated by tidal effects; (ii) open coastal areas where the water exchange is regulated by coastal currents; and (iii) semi-enclosed archipelago coasts. The coastal model gives the fluxes to and from the following four abiotic compartments: surface water, deep water, ET areas (i.e., areas where fine sediment erosion and transport processes dominate the bottom dynamic conditions and resuspension appears) and A-areas (i.e., areas of continuous fine sediment accumulation). Criteria to define the boundaries for the given coastal area towards the sea, and to define whether a coastal area is open or closed are given in operational terms. The model is simple to apply since all driving variables may be readily accessed from maps and standard monitoring programs. The driving variables are: latitude, catchment area, mean annual precipitation, fallout and month of fallout and parameters expressing coastal size and form as determined from, e.g., digitized bathymetric maps using a GIS program. Selected results: the predictions of radionuclide concentrations in water and fish largely depend on two factors, the concentration in the sea outside the given

  4. Vegetation dynamics drive segregation by body size in Galapagos tortoises migrating across altitudinal gradients.

    Science.gov (United States)

    Blake, Stephen; Yackulic, Charles B; Cabrera, Fredy; Tapia, Washington; Gibbs, James P; Kümmeth, Franz; Wikelski, Martin

    2013-03-01

    Seasonal migration has evolved in many taxa as a response to predictable spatial and temporal variation in the environment. Individual traits, physiology and social state interact with environmental factors to increase the complexity of migratory systems. Despite a huge body of research, the ultimate causes of migration remain unclear. A relatively simple, tractable system - giant tortoises on Santa Cruz Island, Galapagos, was studied to elucidate the roles of environmental variation and individual traits in a partial migratory system. Specifically, we asked: (i) do Galapagos tortoises undergo long-distance seasonal migrations? (ii) is tortoise migration ultimately driven by gradients in forage quality or temperature; and (iii) how do sex and body size influence migration patterns? We recorded the daily locations of 17 GPS-tagged tortoises and walked a monthly survey along the altitudinal gradient to characterize the movements and distribution of tortoises of different sizes and sexes. Monthly temperature and rainfall data were obtained from weather stations deployed at various altitudes, and the Normalized Difference Vegetation Index was used as a proxy for forage quality. Analyses using net displacement or daily movement characteristics did not agree on assigning individuals as either migratory or non-migratory; however, both methods suggested that some individuals were migratory. Adult tortoises of both sexes move up and down an altitudinal gradient in response to changes in vegetation dynamics, not temperature. The largest tagged individuals all moved, whereas only some mid-sized individuals moved, and the smallest individuals never left lowland areas. The timing of movements varied with body size: large individuals moved upward (as lowland forage quality declined) earlier in the year than did mid-sized individuals, while the timing of downward movements was unrelated to body size and occurred as lowland vegetation productivity peaked. Giant tortoises are

  5. Grassland Aboveground Biomass in Inner Mongolia: Dynamics (2001-2016) and Driving force

    Science.gov (United States)

    Li, F.; Zeng, Y.; Chen, J.; Wu, B.

    2017-12-01

    Plant biomass is the most critical measure of carbon stored in an ecosystem, yet it remains imprecisely modeled for many terrestrial biomes. This lack of modeling capacity for biomass and its change through time and space has impeded scientists from making headway concerning issues in the geographic and social sciences. Satellite remote sensing techniques excel at detecting changes in the Earth's surface; however, accurate estimates of biomass for the heterogeneous biome landscapes based on remote sensing techniques are few and far between, which has led to many repetitive studies. Here, we argued that our ability to assess biomass in a heterogeneous landscape using satellite remote sensing techniques would be effectively enhanced through a stratification of landscapes, i.e homogenizing landscapes. Specifically, above-ground biomass (AGB) for an extended heterogeneous grassland biome over the entirety of Inner Mongolia during the past 16 years (2001-2016) was explored using remote sensing time series data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Massive and extensive in-situ measurement AGB data and pure vegetation index (PVI) models, developed from normal remote sensing vegetation indices such as the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI), were highlighted in the accomplishment of this study. Taking into full consideration the landscape heterogeneity for the grassland biome over Inner Mongolia, we achieved a series of AGB models with high R2 (>0.85) and low RMSE ( 20.85 g/m2). The total average amount of fresh AGB for the entirety of Inner Mongolia grasslands over the past 16 years was estimated as 87 Tg with an inter-annual standard deviation of 9 Tg. Overall, the grassland AGB for Inner Mongolia increased sporadically. We found that the dynamics of AGB in the grassland biome of Inner Mongolia were substantially dominated by variation in precipitation despite the accommodation of a huge

  6. The Role of Driving Factors in Historical and Projected Carbon Dynamics in Wetland Ecosystems of Alaska

    Science.gov (United States)

    Lyu, Z.; Helene, G.; He, Y.; Zhuang, Q.; McGuire, A. D.; Bennett, A.; Breen, A. L.; Clein, J.; Euskirchen, E. S.; Johnson, K. D.; Kurkowski, T. A.; Pastick, N. J.; Rupp, S. T.; Wylie, B. K.; Zhu, Z.

    2017-12-01

    Wetlands are important terrestrial ecosystems in Alaska. It is important to understand and assess their role in the regional carbon dynamics in response to historical and projected environmental conditions. A coupled modeling framework that incorporates a fire disturbance model and two biogeochemical models was used to assess the relative influence of changing climate, atmospheric carbon dioxide (CO2) concentration, and fire regime on the historical and future carbon balance in wetland ecosystems of the four main Landscape Conservation Cooperatives (LCCs) of Alaska. Simulations were conducted for the historical period (1950-2009) and future projection period (2010-2099). These simulations estimate that the total carbon (C) storage in wetland ecosystems of Alaska is 5556 Tg C in 2009, with 89% of the C stored in soils. An estimated 175 Tg C was lost during the historical period, which is attributed to greater C lost from the Northwest Boreal LCC than C gained from the other three LCCs. The simulations for the projection period were conducted for six different scenarios driven by climate forcings from two different climate models for each of three CO2 emission scenarios. The mean total carbon storage increased 3.94 Tg C/yr by 2099, with variability among the simulations ranging from 2.02 Tg C/yr to 4.42 Tg C/yr. Across the four LCCs, the largest relative C storage increase occurred in the Arctic and North Pacific LCCs. These increases were primarily driven by increases in net primary production (NPP) that were greater than increases in heterotrophic respiration and fire emissions. Our analysis further indicates that NPP increase was primarily driven by CO2 fertilization ( 5% per 100 ppmv increase) as well as by increases in air temperature ( 1% per ° increase). Increases air temperature were estimated to be the primary cause for a projected 47.7% mean increase in wetlands biogenic CH4 emissions among the simulations ( 15% per ° increase). The combined effects of

  7. Vehicle dynamics control of four in-wheel motor drive electric vehicle using gain scheduling based on tyre cornering stiffness estimation

    Science.gov (United States)

    Xiong, Lu; Yu, Zhuoping; Wang, Yang; Yang, Chen; Meng, Yufeng

    2012-06-01

    This paper focuses on the vehicle dynamic control system for a four in-wheel motor drive electric vehicle, aiming at improving vehicle stability under critical driving conditions. The vehicle dynamics controller is composed of three modules, i.e. motion following control, control allocation and vehicle state estimation. Considering the strong nonlinearity of the tyres under critical driving conditions, the yaw motion of the vehicle is regulated by gain scheduling control based on the linear quadratic regulator theory. The feed-forward and feedback gains of the controller are updated in real-time by online estimation of the tyre cornering stiffness, so as to ensure the control robustness against environmental disturbances as well as parameter uncertainty. The control allocation module allocates the calculated generalised force requirements to each in-wheel motor based on quadratic programming theory while taking the tyre longitudinal/lateral force coupling characteristic into consideration. Simulations under a variety of driving conditions are carried out to verify the control algorithm. Simulation results indicate that the proposed vehicle stability controller can effectively stabilise the vehicle motion under critical driving conditions.

  8. A Mechanistic Neural Field Theory of How Anesthesia Suppresses Consciousness: Synaptic Drive Dynamics, Bifurcations, Attractors, and Partial State Equipartitioning.

    Science.gov (United States)

    Hou, Saing Paul; Haddad, Wassim M; Meskin, Nader; Bailey, James M

    2015-12-01

    With the advances in biochemistry, molecular biology, and neurochemistry there has been impressive progress in understanding the molecular properties of anesthetic agents. However, there has been little focus on how the molecular properties of anesthetic agents lead to the observed macroscopic property that defines the anesthetic state, that is, lack of responsiveness to noxious stimuli. In this paper, we use dynamical system theory to develop a mechanistic mean field model for neural activity to study the abrupt transition from consciousness to unconsciousness as the concentration of the anesthetic agent increases. The proposed synaptic drive firing-rate model predicts the conscious-unconscious transition as the applied anesthetic concentration increases, where excitatory neural activity is characterized by a Poincaré-Andronov-Hopf bifurcation with the awake state transitioning to a stable limit cycle and then subsequently to an asymptotically stable unconscious equilibrium state. Furthermore, we address the more general question of synchronization and partial state equipartitioning of neural activity without mean field assumptions. This is done by focusing on a postulated subset of inhibitory neurons that are not themselves connected to other inhibitory neurons. Finally, several numerical experiments are presented to illustrate the different aspects of the proposed theory.

  9. Investigation of dynamics of soft X-ray radiation of mixed-material wire-arrays on S-300 pulsed power generator

    NARCIS (Netherlands)

    Cai, HC; Chernenko, AC; Korolev, VD; Ustroev, GI; Ivanov, MI

    2004-01-01

    The dynamics of radiation spectra of fast Z-pinch plasmas was studied. The experiments were carried out on the S-300 pulsed power machine (4 MA, 0.15 Omega, 100 ns). By means of the polychromator, X-ray spectra of imploding wire arrays were measured in the range of 60 divided by 1500 eV, where the

  10. Dynamics of cylindrical converging shock waves interacting with aerodynamic obstacle arrays

    International Nuclear Information System (INIS)

    Vignati, F.; Guardone, A.

    2015-01-01

    Cylindrical converging shock waves interacting with an array of aerodynamic obstacles are investigated numerically for diverse shock strengths and for different obstacle configurations in air in standard conditions. The considered number of obstacles N is 4, 6, 8, 16, and 24. Obstacles are lenticular airfoils with thickness-to-chord ratios t/c of 0.07, 0.14, and 0.21. The distances of the airfoil leading edge from the shock focus point (r LE )/(r LE ref ) are 1, 2, and 2.5, where r LE ref =7 is the dimensionless reference distance from the origin. Considered impinging shock Mach numbers M s are 2.2, 2.7, and 3.2 at the reference distance from the origin. The reference experimental configuration (N=8,t/c =0.14,r LE =7,M s =2.7) was proposed by Kjellander et al. [“Thermal radiation from a converging shock implosion,” Phys. Fluids 22, 046102 (2010)]. Numerical results compare fairly well to available one-dimensional models for shock propagation and to available experimental results in the reference configuration. Local reflection types are in good agreement with the classical criteria for planar shock waves. The main shock reshaping patterns are identified and their dependence on the shock strength and obstacle configuration is exposed. In particular, different shock patterns are observed after the leading edge reflection, which results in polygonal shock wave with N, 2N, 3N, and 4N sides. The largest temperature peak at the origin is obtained for the 8- and the 16-obstacle configurations and for the smallest thickness to length ratio, 0.07, located at distance from the origin of 2r LE ref . In terms of compression efficiency at the origin, the 16-obstacle configuration is found to perform slightly better than the reference 8-obstacle configuration—with an efficiency increase of about 2%-3%, which is well within the model accuracy—thus confirming the goodness of the obstacle arrangement proposed by Kjellander and collaborators

  11. DMPD: Toll-like receptors, Notch ligands, and cytokines drive the chronicity of lunginflammation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18073395 Toll-like receptors, Notch ligands, and cytokines drive the chronicity of ...2007 Dec;4(8):635-41. (.png) (.svg) (.html) (.csml) Show Toll-like receptors, Notch ligands, and cytokines d...ors, Notch ligands, and cytokines drive the chronicity of lunginflammation. Authors Raymond T, Schaller M, H

  12. Field programmable gate array-based real-time optical Doppler tomography system for in vivo imaging of cardiac dynamics in the chick embryo

    DEFF Research Database (Denmark)

    Thrane, Lars; Larsen, Henning Engelbrecht; Norozi, Kambiz

    2009-01-01

    We demonstrate a field programmable gate-array-based real-time optical Doppler tomography system. A complex-valued bandpass filter is used for the first time in optical coherence tomography signal processing to create the analytic signal. This method simplifies the filter design, and allows...... digital computer (CORDIC) algorithm, which is an efficient algorithm that maps well to the field programmable gate array. Flow phantom experiments, and the use of this system for in vivo imaging of cardiac dynamics in the chick embryo, are presented. We demonstrate the visualization of blood flow...

  13. Microelectrode array analysis of hippocampal network dynamics following theta-burst stimulation via current source density reconstruction by Gaussian interpolation.

    Science.gov (United States)

    Kim, Hyun-Bum; Oh, Tong-In; Swanberg, Kelley M; Lee, Mun-Bae; Kim, Tae-Woo; Woo, Eung-Je; Park, Ji-Ho; Kwon, Oh-In

    2016-05-01

    Multielectrode arrays (MEAs) have been used to understand electrophysiological network dynamics by recording real-time activity in groups of cells. The extent to which the collection of such data enables hypothesis testing on the level of circuits and networks depends largely on the sophistication of the analyses applied. We studied the systemic temporal variations of endogenous signaling within an organotypic hippocampal network following theta-burst stimulation (TBS) to the Schaffer collateral-commissural pathways. The recovered current source density (CSD) information from the raw grid of extracellular potentials by using a Gaussian interpolation method increases spatial resolution and avoids border artifacts by numerical differentials. We compared total sink and source currents in DG, CA3, and CA1; calculated accumulated correlation coefficients to compare pre- with post-stimulation CSD dynamics in each region; and reconstructed functional connectivity maps for regional cross-correlations with respect to temporal CSD variations. The functional connectivity maps for potential correlations pre- and post-TBS were compared to investigate the neural network as a whole, revealing differences post-TBS. Previous MEA work on plasticity in hippocampal evoked potentials has focused on synchronicity across the hippocampus within isolated subregions. Such analyses ignore the complex relationships among diverse components of the hippocampal circuitry, thus failing to capture network-level behaviors integral to understanding hippocampal function. The proposed method of recovering current source density to examine whole-hippocampal function is sensitive to experimental manipulation and is worth further examination in the context of network-level analyses of neural signaling. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Enhanced photocurrent and dynamic response in vertically aligned In₂S₃/Ag core/shell nanorod array photoconductive devices.

    Science.gov (United States)

    Cansizoglu, Hilal; Cansizoglu, Mehmet F; Watanabe, Fumiya; Karabacak, Tansel

    2014-06-11

    Enhanced photocurrent values were achieved through a semiconductor-core/metal-shell nanorod array photoconductive device geometry. Vertically aligned indium sulfide (In2S3) nanorods were formed as the core by using glancing angle deposition technique (GLAD). A thin silver (Ag) layer is conformally coated around nanorods as the metallic shell through a high pressure sputter deposition method. This was followed by capping the nanorods with a metallic blanket layer of Ag film by utilizing a new small angle deposition technique combined with GLAD. Radial interface that was formed by the core/shell geometry provided an efficient charge carrier collection by shortening carrier transit times, which led to a superior photocurrent and gain. Thin metal shells around nanorods acted as a passivation layer to decrease surface states that cause prolonged carrier lifetimes and slow recovery of the photocurrent in nanorods. A combination of efficient carrier collection with surface passivation resulted in enhanced photocurrent and dynamic response at the same time in one device structure. In2S3 nanorod devices without the metal shell and with relatively thicker metal shell were also fabricated and characterized for comparison. In2S3 nanorods with thin metal shell showed the highest photosensitivity (photocurrent/dark current) response compared to two other designs. Microstructural, morphological, and electronic properties of the core/shell nanorods were used to explain the results observed.

  15. Constraining lightning channel growth dynamics by comparison of time domain electromagnetic simulations to Huntsville Alabama Marx Meter Array observations

    Science.gov (United States)

    Carlson, B. E.; Bitzer, P. M.; Burchfield, J.

    2015-12-01

    Major unknowns in lightning research include the mechanism and dynamics of lightning channel extension. Such processes are most simple during the initial growth of the channel, when the channel is relatively short and has not yet branched extensively throughout the cloud. During this initial growth phase, impulsive electromagnetic emissions (preliminary breakdown pulses) can be well-described as produced by current pulses generated as the channel extends, but the overall growth rate, channel geometry, and degree of branching are not known. We approach such issues by examining electric field change measurements made with the Huntsville Alabama Marx Meter Array (HAMMA) during the first few milliseconds of growth of a lightning discharge. We compare HAMMA observations of electromagnetic emissions and overall field change to models of lightning channel growth and development and attempt to constrain channel growth rate, degree of branching, channel physical properties, and uniformity of thunderstorm electric field. Preliminary comparisons suggest that the lightning channel branches relatively early in the discharge, though more complete and detailed analysis will be presented.

  16. Dementia & Driving

    Science.gov (United States)

    ... find the loss of driving privileges and the inherent loss of independence upsetting. Encourage the individual with ... to modify their driving. This can reduce the risk of an accident if the individual’s driving skills ...

  17. Drive Stands

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

  18. Operating scheme for the light-emitting diode array of a volumetric display that exhibits multiple full-color dynamic images

    Science.gov (United States)

    Hirayama, Ryuji; Shiraki, Atsushi; Nakayama, Hirotaka; Kakue, Takashi; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

    2017-07-01

    We designed and developed a control circuit for a three-dimensional (3-D) light-emitting diode (LED) array to be used in volumetric displays exhibiting full-color dynamic 3-D images. The circuit was implemented on a field-programmable gate array; therefore, pulse-width modulation, which requires high-speed processing, could be operated in real time. We experimentally evaluated the developed system by measuring the luminance of an LED with varying input and confirmed that the system works appropriately. In addition, we demonstrated that the volumetric display exhibits different full-color dynamic two-dimensional images in two orthogonal directions. Each of the exhibited images could be obtained only from the prescribed viewpoint. Such directional characteristics of the system are beneficial for applications, including digital signage, security systems, art, and amusement.

  19. Theobroma cacao L. pathogenesis-related gene tandem array members show diverse expression dynamics in response to pathogen colonization.

    Science.gov (United States)

    Fister, Andrew S; Mejia, Luis C; Zhang, Yufan; Herre, Edward Allen; Maximova, Siela N; Guiltinan, Mark J

    2016-05-17

    The pathogenesis-related (PR) group of proteins are operationally defined as polypeptides that increase in concentration in plant tissues upon contact with a pathogen. To date, 17 classes of highly divergent proteins have been described that act through multiple mechanisms of pathogen resistance. Characterizing these families in cacao, an economically important tree crop, and comparing the families to those in other species, is an important step in understanding cacao's immune response. Using publically available resources, all members of the 17 recognized pathogenesis-related gene families in the genome of Theobroma cacao were identified and annotated resulting in a set of ~350 members in both published cacao genomes. Approximately 50 % of these genes are organized in tandem arrays scattered throughout the genome. This feature was observed in five additional plant taxa (three dicots and two monocots), suggesting that tandem duplication has played an important role in the evolution of the PR genes in higher plants. Expression profiling captured the dynamics and complexity of PR genes expression at basal levels and after induction by two cacao pathogens (the oomycete, Phytophthora palmivora, and the fungus, Colletotrichum theobromicola), identifying specific genes within families that are more responsive to pathogen challenge. Subsequent qRT-PCR validated the induction of several PR-1, PR-3, PR-4, and PR-10 family members, with greater than 1000 fold induction detected for specific genes. We describe candidate genes that are likely to be involved in cacao's defense against Phytophthora and Colletotrichum infection and could be potentially useful for marker-assisted selection for breeding of disease resistant cacao varieties. The data presented here, along with existing cacao-omics resources, will enable targeted functional genetic screening of defense genes likely to play critical functions in cacao's defense against its pathogens.

  20. Fast Dynamic Arrays

    DEFF Research Database (Denmark)

    Bille, Philip; Christiansen, Anders Roy; Ettienne, Mikko Berggren

    2017-01-01

    We present a highly optimized implementation of tiered vectors, a data structure for maintaining a sequence of n elements supporting access in time O(1) and insertion and deletion in time O(n) for > 0 while using o(n) extra space. We consider several different implementation optimizations in C++ ...

  1. SU-E-T-82: A Study On Enhanced Dynamic Wedge (EDW) Dosimetry Using 2D Seven29 Ion Chamber Array Detector

    International Nuclear Information System (INIS)

    Kumar, Syam; Aparna

    2015-01-01

    Purpose: To study the dosimetric properties of Enhanced Dynamic Wedge (EDW) using PTW Seven29 ion chamber array Methods: PTW Seven29 ion chamber array and Solid Water phantoms for different depths were used for the study. The study was carried out in Varian Clinac ix with photon energies, 6MV & 15MV. Primarily the solid water phantoms with the 2D array were scanned using a CT scanner (GE Optima 580) at different depths. These scanned images were used for EDW planning in an Eclipse treatment planning system (version 10). Planning was done for different wedge angles and for different depths for 6MV & 15MV. A dose of 100 CGy was delivered in each cases. For each delivery, calculated the Monitoring Unit (MU) required. Same set-up was created before delivering the plans in Varian Clinac-ix. For each clinically relevant depth and for different wedge angles, the same MU was delivered as calculated. Different wedged dose distributions where reconstructed from the measured 2D array data using the in-house developed excel program. Results: It is observed that the shoulder like region in the profile which reduces as depth increases. For the same depth and energy, the percentage difference between planned and measured dose is lesser than 3%. For smaller wedge angles, the percentage difference is found to be greater than 3% for the largest wedge angle. Standard deviation between measured doses at shoulder region for planned and measured profiles is 0.08 and 0.02 respectively. Standard deviations between planned and measured wedge factors for different depths (2.5cm, 5cm, 10cm, and 15cm) are (0.0021, 0.0007, 0.0050, 0.0001) for 6MV and (0.0024, 0.0191, 0.0013, 0.0005) for 15MV respectively. Conclusion: The 2D Seven29 ion chamber array is a good tool for the Enhanced Dynamic Wedge (EDW) dosimetry

  2. Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model

    NARCIS (Netherlands)

    Sakschewski, B.; Bloh, von W.; Boit, A.; Rammig, A.; Kattge, J.; Poorter, L.; Peñualeas, J.; Thonicke, K.

    2015-01-01

    Functional diversity is critical for ecosystem dynamics, stability and productivity. However, dynamic global vegetation models (DGVMs) which are increasingly used to simulate ecosystem functions under global change, condense functional diversity to plant functional types (PFTs) with constant

  3. On-road magnetic emissions prediction of electric cars in terms of driving dynamics using neural networks

    NARCIS (Netherlands)

    Wefky, Ahmed M.; Espinosa, Felipe; Leferink, Frank Bernardus Johannes; Gardel, Alfredo; Vogt-Ardatjew, R.A.

    2013-01-01

    This paper presents a novel artificial neural network (ANN) model estimating vehicle-level radiated magnetic emissions of an electric car as a function of the corresponding driving pattern. Real world electromagnetic interference (EMI) experiments have been realized in a semi-anechoic chamber using

  4. THE INFLUENCE OF POWER STATOR WINDINGS OF THE ASYNCHRONOUS TRACTION MOTORS FOR DYNAMIC WORKLOAD ELEMENTS OF TRACTION DRIVE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    O. M. Bondarev

    2010-01-01

    Full Text Available The results of studies on determination of loading level of tractive drive elements in some operating conditions, when the values of frequencies of the change of feeding currents of stator windings are to be obtained in both subcritical and ultracritical zones for two types of the tractive gear are presented in the paper.

  5. A Self-Adaptive Dynamic Recognition Model for Fatigue Driving Based on Multi-Source Information and Two Levels of Fusion

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2015-09-01

    Full Text Available To improve the effectiveness and robustness of fatigue driving recognition, a self-adaptive dynamic recognition model is proposed that incorporates information from multiple sources and involves two sequential levels of fusion, constructed at the feature level and the decision level. Compared with existing models, the proposed model introduces a dynamic basic probability assignment (BPA to the decision-level fusion such that the weight of each feature source can change dynamically with the real-time fatigue feature measurements. Further, the proposed model can combine the fatigue state at the previous time step in the decision-level fusion to improve the robustness of the fatigue driving recognition. An improved correction strategy of the BPA is also proposed to accommodate the decision conflict caused by external disturbances. Results from field experiments demonstrate that the effectiveness and robustness of the proposed model are better than those of models based on a single fatigue feature and/or single-source information fusion, especially when the most effective fatigue features are used in the proposed model.

  6. Anomalies in vortex lattice dynamics driven by induced ac currents in superconducting films with magnetic arrays of two-fold symmetry

    Science.gov (United States)

    Moreno, A. J.; Chiliotte, C. E.; Pasquini, G.; Bekeris, V.; Gomez, A.; del Valle, J.; Gonzalez, E. M.; Prieto, J. L.; Vicent, J. L.

    2015-01-01

    We study the dynamics of the vortex lattice driven by ac induced currents in the critical state regime, for T > 0.70 TC. The samples are superconducting films grown on top of two-fold symmetry array of magnetic dots. In these heterostructures, the induced ac currents flow parallel to the short and to the long side of the pinning array in different areas of the samples simultaneously. This behavior produces remarkable effects in the vortex lattice dynamics. First of all, periodic features are observed in the ac susceptibility versus applied magnetic field measurements which are related to matching effects between the vortex lattices and the magnetic array. However, the vortex lattice reconfiguration observed in magnetotransport experiments is absent. Some of these features are revealed as maxima instead of being minima, indicating higher mobility at certain matching fields. Competing unstable vortex configurations could lead to increase vortex mobility precluding the reconfiguration transition. At high temperatures, where the matching effects show up, the magnetic permeability of the dots is the mechanism that governs the JC(T) behavior. Moreover, the temperature dependence of the pinning force FP(T) shows a temperature crossover related to an unexpected enhancement in vortex mobility. Vortex-vortex interaction and the interplay between trapped and interstitial vortices are a hint to explain these phenomena.

  7. Analysis of Dynamic Characteristic for Solar Arrays in Series and Global Maximum Power Point Tracking Based on Optimal Initial Value Incremental Conductance Strategy under Partially Shaded Conditions

    Directory of Open Access Journals (Sweden)

    Jian Zhao

    2017-01-01

    Full Text Available Partial shading (PS is an unavoidable condition which significantly reduces the efficiency and stability of a photovoltaic (PV system. With PS, the system usually exhibits multiple-peak output power characteristics, but single-peak is also possible under special PS conditions. In fact it is shown that the partial shading condition (PSC is the necessary but not sufficient condition for multiple-peak. Based on circuit analysis, this paper shows that the number of peak points can be determined by short-circuit currents and maximum-power point currents of all the arrays in series. Then the principle is established based on which the number of the peak points is to be determined. Furthermore, based on the dynamic characteristic of solar array, this paper establishes the rule for determination of the relative position of the global maximum power point (GMPP. In order to track the GMPP within an appropriate period, a reliable technique and the corresponding computer algorithm are developed for GMPP tracking (GMPPT control. It exploits a definable nonlinear relation has been found between variable environmental parameters and the output current of solar arrays at every maximum power point, obtained based on the dynamic performance corresponding to PSC. Finally, the proposed method is validated with MATLAB®/Simulink® simulations and actual experiments. It is shown that the GMPPT of a PV generation system is indeed realized efficiently in a realistic environment with partial shading conditions.

  8. 2D Electrostatic Actuation of Microshutter Arrays

    Science.gov (United States)

    Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Jones, Justin S.; Kelly, Daniel P.; Zheng, Yun; Kutyrev, Alexander S.; Moseley, Samuel H.

    2015-01-01

    An electrostatically actuated microshutter array consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutter arrays demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.

  9. Vector Control System Design for Four Degree-of-Freedom Dynamic Flexible Simulation of the Variable-Frequency Drive

    Directory of Open Access Journals (Sweden)

    Kladiev Sergey N.

    2017-01-01

    Full Text Available In the present work we investigate the control system development of the drive simulators to train driver/operator driving skills, taking into account the ever-changing terrain. In order to meet the required response of the four degree-of-freedom motion platform servomotor current studies have been focused on the vector control of the resistance motor angular velocity from the sensor being incremental encoder. In proposed system the standard security of the frequency converter is realized. It leads to overload capacity of two times within minutes determined by servomotor inertia. Further, we represent the algorithms: positional limitation, reliable acceleration and restraint, frequency break. As well as we demonstrate the position switches implement in software. As a result, the control system commands the control of the angular position of the platform in coordinates.

  10. Magnetic arrays

    Science.gov (United States)

    Trumper, D.L.; Kim, W.; Williams, M.E.

    1997-05-20

    Electromagnet arrays are disclosed which can provide selected field patterns in either two or three dimensions, and in particular, which can provide single-sided field patterns in two or three dimensions. These features are achieved by providing arrays which have current densities that vary in the windings both parallel to the array and in the direction of array thickness. 12 figs.

  11. Magnetic arrays

    Energy Technology Data Exchange (ETDEWEB)

    Trumper, David L. (Plaistow, NH); Kim, Won-jong (Cambridge, MA); Williams, Mark E. (Pelham, NH)

    1997-05-20

    Electromagnet arrays which can provide selected field patterns in either two or three dimensions, and in particular, which can provide single-sided field patterns in two or three dimensions. These features are achieved by providing arrays which have current densities that vary in the windings both parallel to the array and in the direction of array thickness.

  12. Study of the dynamics of the lower hybrid wave during current drive in tokamaks and of the Weyl-Wigner in quantum mechanics

    International Nuclear Information System (INIS)

    Bizarro, J.P.

    1993-10-01

    A comprehensive and detailed investigation is presented on the dynamics of the lower hybrid wave during current drive in tokamaks in situations where toroidally induced ray stochasticity is important and on the Weyl-Wigner formalism for rotation angle and angular momentum variables in quantum mechanics. It is shown that ray-tracing and Fokker-Planck codes are reliable tools for modelling the physics of lower-hybrid current drive provided a large number of rays is used when stochastic effects are important, and, in particular, that such codes are capable of reproducing the experimentally observed features of the hard X-ray emission. The balance between the wave damping and the stochastic divergence of nearby ray trajectories appears to be of great importance in governing the dynamics of the launched power spectrum and in establishing the characteristics of the deposition patterns. The implications of rotational periodicity and of angular momentum quantization for the Weyl-Wigner formalism are analyzed. Particular attention is paid to discreteness and its consequences: importance of evenness and oddness, use of two difference operators instead of one differential operator. 24 refs

  13. Driving Forces of Dynamic Changes in Soil Erosion in the Dahei Mountain Ecological Restoration Area of Northern China Based on GIS and RS.

    Science.gov (United States)

    Li, Xiao; Niu, Xiang; Wang, Bing; Gao, Peng; Liu, Yu

    2016-01-01

    Dynamic change in soil erosion is an important focus of regional ecological restoration research. Here, the dynamic changes of soil erosion and its driving forces in the Dahei Mountain ecological restoration area of northern China were analyzed by LANDSAT TM remote sensing captured via geographic information system (GIS) technologies during three typical periods in 2004, 2008 and 2013. The results showed the following: (1) a decrease in intensive erosion and moderate erosion areas, as well as an increase in light erosion areas, was observed during two periods: one from 2004 to 2008 and the other from 2008 to 2013. (2) Between 2004 and 2008, the variation in the range of slight erosion was the largest (24.28%), followed by light erosion and intensive erosion; between 2008 and 2013, the variation in the range of intensive erosion area was the largest (9.89%), followed by slight erosion and moderate erosion. (3) Socioeconomic impact, accompanied by natural environmental factors, was the main driving force underlying the change in soil erosion within the ecological restoration area. In particular, the socioeconomic factors of per capita forest area and land reclamation rate, as well as the natural environmental factor of terrain slope, significantly influenced soil erosion changes within the ecological restoration area.

  14. Driving Forces of Dynamic Changes in Soil Erosion in the Dahei Mountain Ecological Restoration Area of Northern China Based on GIS and RS

    Science.gov (United States)

    Li, Xiao; Niu, Xiang; Wang, Bing; Gao, Peng; Liu, Yu

    2016-01-01

    Dynamic change in soil erosion is an important focus of regional ecological restoration research. Here, the dynamic changes of soil erosion and its driving forces in the Dahei Mountain ecological restoration area of northern China were analyzed by LANDSAT TM remote sensing captured via geographic information system (GIS) technologies during three typical periods in 2004, 2008 and 2013. The results showed the following: (1) a decrease in intensive erosion and moderate erosion areas, as well as an increase in light erosion areas, was observed during two periods: one from 2004 to 2008 and the other from 2008 to 2013. (2) Between 2004 and 2008, the variation in the range of slight erosion was the largest (24.28%), followed by light erosion and intensive erosion; between 2008 and 2013, the variation in the range of intensive erosion area was the largest (9.89%), followed by slight erosion and moderate erosion. (3) Socioeconomic impact, accompanied by natural environmental factors, was the main driving force underlying the change in soil erosion within the ecological restoration area. In particular, the socioeconomic factors of per capita forest area and land reclamation rate, as well as the natural environmental factor of terrain slope, significantly influenced soil erosion changes within the ecological restoration area. PMID:26981637

  15. Response of Land-Sea Interface in Xiamen Bay to Extreme Weather Events Observed with the Ecological Dynamic Buoy Array, a Multifunctional Sensors System

    Science.gov (United States)

    Wu, J.; Hong, H.; Pan, W.; Zhang, C.

    2016-12-01

    Recent climate observations suggest that global climate change may result in an increase of extreme weather events (such as tropical cyclones, intense precipitation i.e. heavy rains) in frequency and/or intensity in certain world regions. Subtropical coastal regions are often densely populated areas experiencing rapid development and widespread changes to the aquatic environment. The biogeochemical and ecological responses of coastal systems to extreme weather events are of increasing concern. Enhanced river nutrients input following rain storms has been linked to the ecological responses at land-sea interface. These land-sea interactions can be studied using multifunctional sensors systems. In our study, the Ecological Dynamic Buoy Array, a monitoring system with multiple sensors, was deployed in Xiamen Bay for near real time measurements of different parameters. The Ecological Dynamic Buoy Array is a deep water net cage which functions in long-term synchronous observation of dynamic ecological characteristics with the support of an aerograph, water-watch, LOBO (Land/Ocean Biogeochemical Observatory), ADCP, CTD chain system, YSI vertical profiler, flow cytometer, sea surface camera, and "communication box". The study showed that rain storms during multiple typhoons resulted in greater fluctuations of salinity, N concentration, and other water environmental conditions, which might have been connected with algal blooms (so-called red tide) in Xiamen Bay.

  16. Integrated analysis of DFIG drive-train and power electronics dynamics during electrical AC faults and wind disturbances

    DEFF Research Database (Denmark)

    Barahona Garzón, Braulio; Sørensen, Poul Ejnar; Anaya-Lara, Olimpo

    2013-01-01

    The dynamics of a 2 MW DFIG wind turbine are studied during electrical AC faults, and wind disturbances. A simulation platform that couples HAWC2, and Matlab/Simulink was used. High frequencies of the gear box, and power electronics are neglected. It was shown that the dynamics of the dc......-link are influenced by turbulence, and wind gusts. An AC fault that triggers protection systems was simulated, and the influence on the dc-link voltage, shaft and tower loading illustrated....

  17. DNA electrophoresis through microlithographic arrays

    International Nuclear Information System (INIS)

    Sevick, E.M.; Williams, D.R.M.

    1996-01-01

    Electrophoresis is one of the most widely used techniques in biochemistry and genetics for size-separating charged molecular chains such as DNA or synthetic polyelectrolytes. The separation is achieved by driving the chains through a gel with an external electric field. As a result of the field and the obstacles that the medium provides, the chains have different mobilities and are physically separated after a given process time. The macroscopically observed mobility scales inversely with chain size: small molecules move through the medium quickly while larger molecules move more slowly. However, electrophoresis remains a tool that has yet to be optimised for most efficient size separation of polyelectrolytes, particularly large polyelectrolytes, e.g. DNA in excess of 30-50 kbp. Microlithographic arrays etched with an ordered pattern of obstacles provide an attractive alternative to gel media and provide wider avenues for size separation of polyelectrolytes and promote a better understanding of the separation process. Its advantages over gels are (1) the ordered array is durable and can be re-used, (2) the array morphology is ordered and can be standardized for specific separation, and (3) calibration with a marker polyelectrolyte is not required as the array is reproduced to high precision. Most importantly, the array geometry can be graduated along the chip so as to expand the size-dependent regime over larger chain lengths and postpone saturation. In order to predict the effect of obstacles upon the chain-length dependence in mobility and hence, size separation, we study the dynamics of single chains using theory and simulation. We present recent work describing: 1) the release kinetics of a single DNA molecule hooked around a point, frictionless obstacle and in both weak and strong field limits, 2) the mobility of a chain impinging upon point obstacles in an ordered array of obstacles, demonstrating the wide range of interactions possible between the chain and

  18. Using seismic arrays to quantify the physics of a glacial outburst flood and its legacy on upland river dynamics

    Science.gov (United States)

    Gimbert, Florent; Cook, Kristen; Andermann, Christoff; Hovius, Niels; Turowski, Jens

    2017-04-01

    In the Himalayas fluvial erosion is thought to be controlled by the intense annual Indian Summer Monsoon precipitation. However, this region is also exposed to catastrophic floods generated by the sudden failure of landslides or moraine dams. These floods are rare and particularly devastating. Thus they have a strong impact on rivers and adjacent hillslopes, and they represent a hazard for local populations. Due to the difficulties to observe these floods and quantify their physics using traditional methods, their importance for the long-term evolution of Himalayan Rivers remains largely unknown, and no consistent early warning system exists to anticipate these events, especially in trans-boundary regions. Here we show that seismic arrays can be used to (i) reliably anticipate outburst floods and to (ii) quantify multiple and key fluvial processes associated with their propagation and their lasting impacts on upland river dynamics. We report unique seismic observations of a glacial lake outburst flood event that occurred the 5th of July 2016 in the Bhote Koshi River (Central Nepal). Precursory seismic signals are identified from the onset of the lake drainage event such that an early warning alarm may be turned on about an hour before the outburst flood wave reaches areas with an exposed population. Using our network of stations we observe for the first time that the outburst flood wave is in fact made of two distinct waves, namely a water flow wave and a bedload sediment wave. As expected these two waves travel at different speeds. We find that the ratio between the two wave speeds matches with that previously found at much smaller scales in flume laboratory experiments. Based on the physical modelling of both water-flow- and bedload- induced seismic noise we provide estimates of flow depth and bedload transport characteristics (flux, moving grains sizes) prior, during and after the flood. In particular we show that bedload sediment flux is enhanced by up to a

  19. High-efficiency dynamic routing architecture for the readout of single photon avalanche diode arrays in time-correlated measurements

    Science.gov (United States)

    Cominelli, A.; Acconcia, G.; Peronio, P.; Rech, I.; Ghioni, M.

    2017-05-01

    transfer rate towards the elaboration unit. We developed a novel readout architecture, starting from a completely different perspective: considering the maximum data rate we can manage with a PC, a limited set of conversion data is selected and transferred to the elaboration unit during each excitation period, in order to take full advantage of the bus bandwidth toward the PC. In particular, we introduce a smart routing logic, able to dynamically connect a large number of SPAD detectors to a limited set of high-performance external acquisition chains, paving the way for a more efficient use of resources and allowing us to effectively break the tradeoff between integration and performance, which affects the solutions proposed so far. The routing electronic features a pixelated architecture, while 3D-stacking techniques are exploited to connect each SPAD to its dedicated electronic, leading to a minimization of the overall number of interconnections crossing the integrated system, which is one of the main issues in high-density arrays.

  20. The role of deep Earth dynamics in driving the flooding and emergence of New Guinea since the Jurassic

    Science.gov (United States)

    Harrington, Lauren; Zahirovic, Sabin; Flament, Nicolas; Müller, R. Dietmar

    2017-12-01

    The paleogeography of New Guinea indicates fluctuating periods of flooding and emergence since the Jurassic, which are inconsistent with estimates of global sea level change since the Eocene. The role of deep Earth dynamics in explaining these discrepancies has not been explored, despite the strongly time-dependent geodynamic setting within which New Guinea has evolved. We aim to investigate the role of subduction-driven mantle flow in controlling long-wavelength dynamic topography and its manifestation in the regional sedimentary record, within a tectonically complex region leading to orogeny. We couple regionally refined global plate reconstructions with forward geodynamic models to compare trends of dynamic topography with estimates of eustasy and regional paleogeography. Qualitative corroboration of modelled mantle structure with equivalent tomographic profiles allows us to ground-truth the models. We show that predicted dynamic topography correlates with the paleogeographic record of New Guinea from the Jurassic to the present. We find that subduction at the East Gondwana margin locally enhanced the high eustatic sea levels from the Early Cretaceous (∼145 Ma) to generate long-term regional flooding. During the Miocene, however, dynamic subsidence associated with subduction of the Maramuni Arc played a fundamental role in causing long-term inundation of New Guinea during a period of global sea level fall.

  1. Miniaturized Dynamic Pressure Sensor Arrays with Sub-Millimeter (mm) Spacing for Cross-Flow Transition Measurements, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Interdisciplinary Consulting Corporation (IC2) and in partnership with the University of Florida (UF) propose a microfabricated, dynamic piezoelectric pressure...

  2. Miniaturized Dynamic Pressure Sensor Arrays with Sub-Millimeter (mm) Spacing for Cross-Flow Transition Measurements, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Interdisciplinary Consulting Corporation (IC2) and in partnership with the University of Florida (UF) propose a microfabricated, dynamic piezoelectric pressure...

  3. When the Jeans Do Not Fit: How Stellar Feedback Drives Stellar Kinematics and Complicates Dynamical Modeling in Low-mass Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    El-Badry, Kareem; Quataert, Eliot [Department of Astronomy, University of California, Berkeley, CA (United States); Wetzel, Andrew R.; Hopkins, Philip F. [TAPIR, California Institute of Technology, Pasadena, CA (United States); Geha, Marla [Department of Astronomy, Yale University, New Haven, CT (United States); Kereš, Dusan; Chan, T. K. [Department of Physics, Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla (United States); Faucher-Giguère, Claude-André, E-mail: kelbadry@berkeley.edu [Department of Physics and Astronomy and CIERA, Northwestern University, Evanston, IL (United States)

    2017-02-01

    In low-mass galaxies, stellar feedback can drive gas outflows that generate non-equilibrium fluctuations in the gravitational potential. Using cosmological zoom-in baryonic simulations from the Feedback in Realistic Environments project, we investigate how these fluctuations affect stellar kinematics and the reliability of Jeans dynamical modeling in low-mass galaxies. We find that stellar velocity dispersion and anisotropy profiles fluctuate significantly over the course of galaxies’ starburst cycles. We therefore predict an observable correlation between star formation rate and stellar kinematics: dwarf galaxies with higher recent star formation rates should have systemically higher stellar velocity dispersions. This prediction provides an observational test of the role of stellar feedback in regulating both stellar and dark-matter densities in dwarf galaxies. We find that Jeans modeling, which treats galaxies as virialized systems in dynamical equilibrium, overestimates a galaxy’s dynamical mass during periods of post-starburst gas outflow and underestimates it during periods of net inflow. Short-timescale potential fluctuations lead to typical errors of ∼20% in dynamical mass estimates, even if full three-dimensional stellar kinematics—including the orbital anisotropy—are known exactly. When orbital anisotropy is not known a priori, typical mass errors arising from non-equilibrium fluctuations in the potential are larger than those arising from the mass-anisotropy degeneracy. However, Jeans modeling alone cannot reliably constrain the orbital anisotropy, and problematically, it often favors anisotropy models that do not reflect the true profile. If galaxies completely lose their gas and cease forming stars, fluctuations in the potential subside, and Jeans modeling becomes much more reliable.

  4. Dynamic of Dalinor Lakes in the Inner Mongolian Plateau and Its Driving Factors during 1976–2015

    Directory of Open Access Journals (Sweden)

    Haidong Li

    2017-09-01

    Full Text Available Climate change and increasing human activities have induced lake expansion or shrinkage, posing a serious threat to the ecological security on the Inner Mongolian Plateau, China. However, the pattern of lake changes and how it responds to climate change and revegetation have rarely been reported. We investigated the pattern of lake-area changes in the Dalinor National Nature Reserve (DNR using Landsat imagery during 1976–2015, and examined its relationship with changes in climate and vegetation factors. The total lake-area in the DNR has decreased by 11.6% from 1976 to 2015 with a rate of −0.55 km2 year−1. The largest Dalinor Lake reduced the most (by 32.7 km2 with a rate of −0.79 km2 year−1. The air temperature has increased significantly since 1976, with a rate of 0.03 °C year−1 (p < 0.05, while the precipitation slightly decreased during 1976–2015, with a rate of −0.86 mm year−1. The Normalized Difference Vegetation Index (NDVI increased by 27.7% from 1976 to 2015, especially after 2001 when vegetation has been promoted greatly as a result of the successful ecological protection and restoration in the Dalinor basin. The decrease in lake-areas for the DNR exhibited a negative correlation with NDVI (r = −0.397, p < 0.05 during 1976–2015. It seems that decreasing precipitation drives the reduction in lake-area, while rising temperature and vegetation greenness accelerated this decreasing trend by increasing evapotranspiration. The continuous lake shrinkage increases the ecological risks to the habitat of birds, causing a challenge to the management in the DNR.

  5. Drowsy Driving

    Science.gov (United States)

    ... at least 8 hours. 8-9 Develop good sleeping habits such as sticking to a sleep schedule. If ... K, Howard ME. Cognitive components of simulated driving performance: sleep loss effects and predictors. Accid Anal Prev. 2012; ...

  6. Distracted Driving

    Science.gov (United States)

    ... Communities Toolkit Best Practices Guide Publications Motorcycle Safety Bicycle Safety Publications Global Road Safety Get Email Updates ... study. The Insurance Institute for Highway Safety keeps track of distracted driving laws. 7 As of June ...

  7. Rotor-dynamic design aspects for a variable frequency drive based high speed cryogenic centrifugal pump in fusion devices

    International Nuclear Information System (INIS)

    Das, Jotirmoy; Vaghela, Hitensinh; Bhattacharya, Ritendra; Patel, Pratik; Shukla, Vinit; Shah, Nitin; Sarkar, Biswanath

    2015-01-01

    Superconducting magnets of large size are inevitable for fusion devices due to high magnetic field requirements. Forced flow cooling of the superconducting magnets with high mass flowrate of the order ∼3 kg/s is required to keep superconducting magnets within its safe operational boundaries during various plasma scenarios. This important requirement can be efficiently fulfilled by employing high capacity and high efficiency cryogenic centrifugal pumps. The efficiency > 70% will ensure overall lower heat load to the cryoplant. Thermo-hydraulic design of cryogenic centrifugal pump revealed that to achieve the operational regime with high efficiency, the speed should be ∼ 10,000 revolutions per minute. In this regard, the rotor-dynamic design aspect is quite critical from the operational stability point of view. The rotor shaft design of the cryogenic pump is primarily an outcome of optimization between thermal heat-in leak at cryogenic temperature level from ambient, cryogenic fluid impedance and designed rotation speed of the impeller wheel. The paper describes the basic design related to critical speed of the rotor shaft, rotor whirl and system instability prediction to explore the ideal operational range of the pump from the system stability point of view. In the rotor-dynamic analysis, the paper also describes the Campbell plots to ensure that the pump is not disturbed by any of the critical speeds, especially while operating near the nominal and enhanced operating modes. (author)

  8. The significance of the amorphous potential energy landscape for dictating glassy dynamics and driving solid-state crystallisation

    DEFF Research Database (Denmark)

    Ruggiero, Michael T; Krynski, Marcin; Kissi, Eric Ofosu

    2017-01-01

    The fundamental origins surrounding the dynamics of disordered solids near their characteristic glass transitions continue to be fiercely debated, even though a vast number of materials can form amorphous solids, including small-molecule organic, inorganic, covalent, metallic, and even large...... biological systems. The glass-transition temperature, Tg, can be readily detected by a diverse set of techniques, but given that these measurement modalities probe vastly different processes, there has been significant debate regarding the question of why Tg can be detected across all of them. Here we show...... clear experimental and computational evidence in support of a theory that proposes that the shape and structure of the potential-energy surface (PES) is the fundamental factor underlying the glass-transition processes, regardless of the frequency that experimental methods probe. Whilst this has been...

  9. Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model.

    Science.gov (United States)

    Sakschewski, Boris; von Bloh, Werner; Boit, Alice; Rammig, Anja; Kattge, Jens; Poorter, Lourens; Peñuelas, Josep; Thonicke, Kirsten

    2015-01-22

    Functional diversity is critical for ecosystem dynamics, stability and productivity. However, dynamic global vegetation models (DGVMs) which are increasingly used to simulate ecosystem functions under global change, condense functional diversity to plant functional types (PFTs) with constant parameters. Here, we develop an individual- and trait-based version of the DGVM LPJmL (Lund-Potsdam-Jena managed Land) called LPJmL- flexible individual traits (LPJmL-FIT) with flexible individual traits) which we apply to generate plant trait maps for the Amazon basin. LPJmL-FIT incorporates empirical ranges of five traits of tropical trees extracted from the TRY global plant trait database, namely specific leaf area (SLA), leaf longevity (LL), leaf nitrogen content (N area ), the maximum carboxylation rate of Rubisco per leaf area (vcmaxarea), and wood density (WD). To scale the individual growth performance of trees, the leaf traits are linked by trade-offs based on the leaf economics spectrum, whereas wood density is linked to tree mortality. No preselection of growth strategies is taking place, because individuals with unique trait combinations are uniformly distributed at tree establishment. We validate the modeled trait distributions by empirical trait data and the modeled biomass by a remote sensing product along a climatic gradient. Including trait variability and trade-offs successfully predicts natural trait distributions and achieves a more realistic representation of functional diversity at the local to regional scale. As sites of high climatic variability, the fringes of the Amazon promote trait divergence and the coexistence of multiple tree growth strategies, while lower plant trait diversity is found in the species-rich center of the region with relatively low climatic variability. LPJmL-FIT enables to test hypotheses on the effects of functional biodiversity on ecosystem functioning and to apply the DGVM to current challenges in ecosystem management from local

  10. Community dynamics drive punctuated engraftment of the fecal microbiome following transplantation using freeze-dried, encapsulated fecal microbiota.

    Science.gov (United States)

    Staley, Christopher; Vaughn, Byron P; Graiziger, Carolyn T; Singroy, Stephanie; Hamilton, Matthew J; Yao, Dan; Chen, Chi; Khoruts, Alexander; Sadowsky, Michael J

    2017-05-04

    Fecal microbiota transplantation (FMT) is a highly effective treatment of recurrent and recalcitrant Clostridium difficile infection (rCDI). In a recent study oral-delivery of encapsulated, freeze-dried donor material, resulted in comparable rates of cure to colonoscopic approaches. Here we characterize shifts in the fecal bacterial community structure of patients treated for rCDI using encapsulated donor material. Prior to FMT, patient fecal samples showed declines in diversity and abundance of Firmicutes and Bacteroidetes, with concurrent increases in members of the Proteobacteria, specifically Enterobacteriaceae. Moreover, patients who experienced recurrence of CDI within the 2-month clinical follow-up had greater abundances of Enterobacteriaceae and did not show resolution of dysbioses. Despite resolution of rCDI following oral-administration of encapsulated fecal microbiota, community composition was slow to return to a normal donor-like assemblage. Post-FMT taxa within the Firmicutes showed rapid increases in relative abundance and did not vary significantly over time. Conversely, Bacteroidetes taxa only showed significant increases in abundance after one month post-FMT, corresponding to significant increases in the community attributable to the donors. Changes in the associations among dominant OTUs were observed at days, weeks, and months post-FMT, suggesting shifts in community dynamics may be related to the timing of increases in abundance of specific taxa. Administration of encapsulated, freeze-dried, fecal microbiota to rCDI patients resulted in restoration of bacterial diversity and resolution of dysbiosis. However, shifts in the fecal microbiome were incremental rather than immediate, and may be driven by changes in community dynamics reflecting changes in the host environment.

  11. Field and lab conditions alter microbial enzyme and biomass dynamics driving decomposition of the same leaf litter

    Directory of Open Access Journals (Sweden)

    Zachary L Rinkes

    2013-09-01

    Full Text Available Fluctuations in climate and edaphic factors influence field decomposition rates and preclude a complete understanding of how microbial communities respond to plant litter quality. In contrast, laboratory microcosms isolate the intrinsic effects of litter chemistry and microbial community from extrinsic effects of environmental variation. Used together, these paired approaches provide mechanistic insights to decomposition processes. In order to elucidate the microbial mechanisms underlying how environmental conditions alter the trajectory of decay, we characterized microbial biomass, respiration, enzyme activities, and nutrient dynamics during early (< 10% mass loss, mid- (10-40% mass loss, and late (> 40% mass loss decay in parallel field and laboratory litter bag incubations for deciduous tree litters with varying recalcitrance (dogwood < maple < maple-oak mixture < oak. In the field, mass loss was minimal (< 10% over the first 50 days (January-February, even for labile litter types, despite above-freezing soil temperatures and adequate moisture during these winter months. In contrast, microcosms displayed high C mineralization rates in the first week. During mid-decay, the labile dogwood and maple litters in the field had higher mass loss per unit enzyme activity than the lab, possibly due to leaching of soluble compounds. Microbial biomass to litter mass (B:C ratios peaked in the field during late decay, but B:C ratios declined between mid- and late decay in the lab. Thus, microbial biomass did not have a consistent relationship with litter quality between studies. Higher oxidative enzyme activities in oak litters in the field, and higher nitrogen (N accumulation in the lab microcosms occurred in late decay. We speculate that elevated N suppressed fungal activity and/or biomass in microcosms. Our results suggest that differences in microbial biomass and enzyme dynamics alter the decay trajectory of the same leaf litter under field and lab

  12. Field and lab conditions alter microbial enzyme and biomass dynamics driving decomposition of the same leaf litter.

    Science.gov (United States)

    Rinkes, Zachary L; Sinsabaugh, Robert L; Moorhead, Daryl L; Grandy, A Stuart; Weintraub, Michael N

    2013-01-01

    Fluctuations in climate and edaphic factors influence field decomposition rates and preclude a complete understanding of how microbial communities respond to plant litter quality. In contrast, laboratory microcosms isolate the intrinsic effects of litter chemistry and microbial community from extrinsic effects of environmental variation. Used together, these paired approaches provide mechanistic insights to decomposition processes. In order to elucidate the microbial mechanisms underlying how environmental conditions alter the trajectory of decay, we characterized microbial biomass, respiration, enzyme activities, and nutrient dynamics during early (40% mass loss) decay in parallel field and laboratory litter bag incubations for deciduous tree litters with varying recalcitrance (dogwood litter types, despite above-freezing soil temperatures and adequate moisture during these winter months. In contrast, microcosms displayed high C mineralization rates in the first week. During mid-decay, the labile dogwood and maple litters in the field had higher mass loss per unit enzyme activity than the lab, possibly due to leaching of soluble compounds. Microbial biomass to litter mass (B:C) ratios peaked in the field during late decay, but B:C ratios declined between mid- and late decay in the lab. Thus, microbial biomass did not have a consistent relationship with litter quality between studies. Higher oxidative enzyme activities in oak litters in the field, and higher nitrogen (N) accumulation in the lab microcosms occurred in late decay. We speculate that elevated N suppressed fungal activity and/or biomass in microcosms. Our results suggest that differences in microbial biomass and enzyme dynamics alter the decay trajectory of the same leaf litter under field and lab conditions.

  13. Dynamic Phases of Vortices in Superconductors with Periodic Pinning

    International Nuclear Information System (INIS)

    Reichhardt, C.; Olson, C.; Nori, F.

    1997-01-01

    We present results from extensive simulations of driven vortex lattices interacting with periodic arrays of pinning sites. Changing an applied driving force produces a rich variety of novel dynamical plastic flow phases which are very distinct from those observed in systems with random pinning arrays. Signatures of the transition between these different dynamical phases include sudden jumps in the current-voltage curves as well as marked changes in the vortex trajectories and vortex lattice order. Several dynamical phase diagrams are obtained as a function of commensurability, pinning strength, and spatial order of the pinning sites. copyright 1997 The American Physical Society

  14. CubeSat Modular Deployable Solar Arrays

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced CubeSat missions have demanding power requirements relative to their limited available surface area that drive the need for deployable solar arrays. Vendors...

  15. Driving things

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    2015-01-01

    . pp.155 ((http://www.infrastructure.gov.au/roads/safety/publications/2010/pdf/rsgr_2010001.pdf)) Nevile, M., Haddington, P., Heinemann, T., Rauniomaa, M. (Eds.) Interacting with objects: Language, materiality, and social activity. Amsterdam/Philadelphia: John Benjamins. Redshaw, S. (2008....... Interaction with objects reflects the car’s role beyond mere transport as a site of personal, social, and work life (Featherstone et al. 2005; Redshaw 2008). Studies of interaction examine this role as it is actually enacted, understood, and accomplished, in situ through participants’ practices (e.g. Laurier...... of in-car distractions, and how they impact driving activities (Nevile & Haddington 2010). Data are video recordings of ordinary journeys, capturing drivers and passengers in real-world real-time driving situations (27 hours, 90 journeys). For driving and road safety, research and experience has...

  16. Community Drive

    DEFF Research Database (Denmark)

    Magnussen, Rikke

    2018-01-01

    opportunity to break boundaries between research institutions and surrounding communities through the involvement of new types of actors, knowledge forms and institutions (OECD, 2011). This paper presents the project Community Drive a three year cross disciplinary community-driven game– and data-based project....... In the paper we present how the project Community Drive initiated in May 2018 is based on results from pilot projects conducted from 2014 – 2017. Overall these studies showed that it is a strong motivational factor for students to be given the task to change their living conditions through redesign...... of living in the area. The paper discusses potentials and pitfalls of designing community-driven science gaming environments and how results from previous studies can form the project Community Drive....

  17. Dynamics of nucleus nucleus collisions below 100 MeV/u a study with a 4π detection array

    International Nuclear Information System (INIS)

    Peter, J.

    1990-06-01

    Charged particles and fragments emitted in reactions between 40 Ar, at energies ranging from 25 to 85 MeV/u, and an 27 Al target have been detected in a geometry close to 4π in the center of mass with the multidetector array MUR + TONNEAU. A new global variable, the average parallel velocity, has been used to sort the events as a function of the impact parameter value. The multiplicity of pre-equilibrium charged particles emitted from the interaction region (participants) increases strongly when the impact parameter value decreases, and reaches 7 in head-on reactions. The flow of these particles is attributed to scattering at negative angles. When the energy increases, compression gradually opposes this negative scattering, until the flow falls to zero. This is obtained at a beam energy in the range 70-80 MeV/u for impact parameters below 2 fm and increases with the impact parameter. This study as a function of the impact parameter and the energy should allow information both on the nucleon-nucleon cross section in medium and the equation of state of nuclear matter to be obtained

  18. Array capabilities and future arrays

    International Nuclear Information System (INIS)

    Radford, D.

    1993-01-01

    Early results from the new third-generation instruments GAMMASPHERE and EUROGAM are confirming the expectation that such arrays will have a revolutionary effect on the field of high-spin nuclear structure. When completed, GAMMASHPERE will have a resolving power am order of magnitude greater that of the best second-generation arrays. When combined with other instruments such as particle-detector arrays and fragment mass analysers, the capabilites of the arrays for the study of more exotic nuclei will be further enhanced. In order to better understand the limitations of these instruments, and to design improved future detector systems, it is important to have some intelligible and reliable calculation for the relative resolving power of different instrument designs. The derivation of such a figure of merit will be briefly presented, and the relative sensitivities of arrays currently proposed or under construction presented. The design of TRIGAM, a new third-generation array proposed for Chalk River, will also be discussed. It is instructive to consider how far arrays of Compton-suppressed Ge detectors could be taken. For example, it will be shown that an idealised open-quote perfectclose quotes third-generation array of 1000 detectors has a sensitivity an order of magnitude higher again than that of GAMMASPHERE. Less conventional options for new arrays will also be explored

  19. The demographic impact of extreme events: stochastic weather drives survival and population dynamics in a long-lived seabird.

    Science.gov (United States)

    Frederiksen, M; Daunt, F; Harris, M P; Wanless, S

    2008-09-01

    1. Most scenarios for future climate change predict increased variability and thus increased frequency of extreme weather events. To predict impacts of climate change on wild populations, we need to understand whether this translates into increased variability in demographic parameters, which would lead to reduced population growth rates even without a change in mean parameter values. This requires robust estimates of temporal process variance, for example in survival, and identification of weather covariates linked to interannual variability. 2. The European shag Phalacrocorax aristotelis (L.) shows unusually large variability in population size, and large-scale mortality events have been linked to winter gales. We estimated first-year, second-year and adult survival based on 43 years of ringing and dead recovery data from the Isle of May, Scotland, using recent methods to quantify temporal process variance and identify aspects of winter weather linked to survival. 3. Survival was highly variable for all age groups, and for second-year and adult birds process variance declined strongly when the most extreme year was excluded. Survival in these age groups was low in winters with strong onshore winds and high rainfall. Variation in first-year survival was not related to winter weather, and process variance, although high, was less affected by extreme years. A stochastic population model showed that increasing process variance in survival would lead to reduced population growth rate and increasing probability of extinction. 4. As in other cormorants, shag plumage is only partially waterproof, presumably an adaptation to highly efficient underwater foraging. We speculate that this adaptation may make individuals vulnerable to rough winter weather, leading to boom-and-bust dynamics, where rapid population growth under favourable conditions allows recovery from periodic large-scale weather-related mortality. 5. Given that extreme weather events are predicted to become

  20. The role of Rabi splitting tuning in the dynamics of strongly coupled J-aggregates and surface plasmon polaritons in nanohole arrays.

    Science.gov (United States)

    Wang, Hai; Toma, Andrea; Wang, Hai-Yu; Bozzola, Angelo; Miele, Ermanno; Haddadpour, Ali; Veronis, Georgios; De Angelis, Francesco; Wang, Lei; Chen, Qi-Dai; Xu, Huai-Liang; Sun, Hong-Bo; Zaccaria, Remo Proietti

    2016-07-21

    We have investigated the influence of Rabi splitting tuning on the dynamics of strongly coupled J-aggregate/surface plasmon polariton systems. In particular, the Rabi splitting was tuned by modifying the J-aggregate molecule concentration while a polaritonic system was provided by a nanostructure formed by holes array in a golden layer. From the periodic and concentration changes we have identified, through numerical and experimental steady-state analyses, the best geometrical configuration for maximizing Rabi splitting, which was then used for transient absorption measurements. It was found that in transient absorption spectra, under upper band excitation, two bleaching peaks appear when a nanostructured polaritonic pattern is used. Importantly, their reciprocal distance increases upon increase of J-aggregate concentration, a result confirmed by steady-state analysis. In a similar manner it was also found that the lifetime of the upper band is intimately related to the coupling strength. In particular, we argue that with strong coupling strength, i.e. high J-aggregate concentration, a short lifetime of the upper band has to be expected due to the suppression of the bottleneck effect. This result supports the idea that the dynamics of hybrid systems is profoundly dependent on Rabi splitting.

  1. Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics

    Science.gov (United States)

    Engebretsen, Erik; Hinds, Gareth; Meyer, Quentin; Mason, Tom; Brightman, Edward; Castanheira, Luis; Shearing, Paul R.; Brett, Daniel J. L.

    2018-04-01

    Advances in bespoke diagnostic techniques for polymer electrolyte fuel cells continue to provide unique insight into the internal operation of these devices and lead to improved performance and durability. Localised measurements of current density have proven to be extremely useful in designing better fuel cells and identifying optimal operating strategies, with electrochemical impedance spectroscopy (EIS) now routinely used to deconvolute the various losses in fuel cells. Combining the two techniques provides another dimension of understanding, but until now each localised EIS has been based on 2-electrode measurements, composed of both the anode and cathode responses. This work shows that a reference electrode array can be used to give individual electrode-specific EIS responses, in this case the cathode is focused on to demonstrate the approach. In addition, membrane hydration dynamics are studied under current load steps from open circuit voltage. A three-stage process is identified associated with an initial rapid reduction in membrane resistance after 10 s of applying a current step, followed by a slower ramp to approximately steady state, which was achieved after ∼250 s. These results support previously published work that has looked at membrane swelling dynamics and reveal that membrane hydration/membrane resistance is highly heterogeneous.

  2. Berry's phase, Josephson's equation, and the dynamics of weak link superconductors and their vortices

    International Nuclear Information System (INIS)

    Gaitan, F.; Shenoy, S.R.

    1995-05-01

    We examine the dynamical consequences of Berry's phase for Josephson junctions, junction arrays, and their vortices. Josephson's equation and the related phase slip voltages are shown to be unaffected by Berry's phase. In an annular Josephson junction, Berry's phase is seen to generate a new current drive on a vortex. In the continuum limit, vortex is expected in a 2D array is shown to map onto that of a 2D film. A Hall sing anomaly is expected arrays; and the merits of arrays for studies of disorder on vortex motion is discussed. (author). 12 refs

  3. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...

  4. Vegetation dynamics and its driving forces from climate change and human activities in the Three-River Source Region, China from 1982 to 2012.

    Science.gov (United States)

    Zhang, Ying; Zhang, Chaobin; Wang, Zhaoqi; Chen, Yizhao; Gang, Chengcheng; An, Ru; Li, Jianlong

    2016-09-01

    The Three-River Source Region (TRSR), a region with key importance to the ecological security of China, has undergone climate changes and a shift in human activities driven by a series of ecological restoration projects in recent decades. To reveal the spatiotemporal dynamics of vegetation dynamics and calculate the contributions of driving factors in the TRSR across different periods from 1982 to 2012, net primary productivity (NPP) estimated using the Carnegie-Ames-Stanford approach model was used to assess the status of vegetation. The actual effects of different climatic variation trends on interannual variation in NPP were analyzed. Furthermore, the relationships of NPP with different climate factors and human activities were analyzed quantitatively. Results showed the following: from 1982 to 2012, the average NPP in the study area was 187.37gcm(-2)yr(-1). The average NPP exhibited a fluctuation but presented a generally increasing trend over the 31-year study period, with an increase rate of 1.31gcm(-2)yr(-2). During the entire study period, the average contributions of temperature, precipitation, and solar radiation to NPP interannual variation over the entire region were 0.58, 0.73, and 0.09gcm(-2)yr(-2), respectively. Radiation was the climate factor with the greatest influence on NPP interannual variation. The factor that restricted NPP increase changed from temperature and radiation to precipitation. The average contributions of climate change and human activities to NPP interannual variation were 1.40gcm(-2)yr(-2) and -0.08gcm(-2)yr(-2), respectively. From 1982 to 2000, the general climate conditions were favorable to vegetation recovery, whereas human activities had a weaker negative impact on vegetation growth. From 2001 to 2012, climate conditions began to have a negative impact on vegetation growth, whereas human activities made a favorable impact on vegetation recovery. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Field programmable gate array (FPGA) implementation of dynamic compensation (DyCom) algorithm for vanadium self-powered neutron detectors

    International Nuclear Information System (INIS)

    Das, A.; Dixit, M.Y.; Das, D.; Kulkarni, C.P.; Chaganty, S.P.; Kataria, S.K.; Ramachandiran, V.

    2003-01-01

    Full text: A new on-line digital signal processing (DSP) based Dynamic Compensation (DyCom) algorithm has been developed [Das 1999] to speed-up the response time of slow-responding Vanadium self-powered neutron detectors. The algorithm is based on the principles of direct inversion and on-line nonlinear (median) filtering. The algorithm was tested at different research and power reactors on a PC based platform with encouraging results [Das 2001]. This paper discusses the stand-alone FPGA implementation of the DyCom algorithm with the experimental results obtained with prototype FPGA boards

  6. SNP Arrays

    Directory of Open Access Journals (Sweden)

    Jari Louhelainen

    2016-10-01

    Full Text Available The papers published in this Special Issue “SNP arrays” (Single Nucleotide Polymorphism Arrays focus on several perspectives associated with arrays of this type. The range of papers vary from a case report to reviews, thereby targeting wider audiences working in this field. The research focus of SNP arrays is often human cancers but this Issue expands that focus to include areas such as rare conditions, animal breeding and bioinformatics tools. Given the limited scope, the spectrum of papers is nothing short of remarkable and even from a technical point of view these papers will contribute to the field at a general level. Three of the papers published in this Special Issue focus on the use of various SNP array approaches in the analysis of three different cancer types. Two of the papers concentrate on two very different rare conditions, applying the SNP arrays slightly differently. Finally, two other papers evaluate the use of the SNP arrays in the context of genetic analysis of livestock. The findings reported in these papers help to close gaps in the current literature and also to give guidelines for future applications of SNP arrays.

  7. FPGA implementation of adaptive ANN controller for speed regulation of permanent magnet stepper motor drives

    International Nuclear Information System (INIS)

    Hasanien, Hany M.

    2011-01-01

    This paper presents a novel adaptive artificial neural network (ANN) controller, which applies on permanent magnet stepper motor (PMSM) for regulating its speed. The dynamic response of the PMSM with the proposed controller is studied during the starting process under the full load torque and under load disturbance. The effectiveness of the proposed adaptive ANN controller is then compared with that of the conventional PI controller. The proposed methodology solves the problem of nonlinearities and load changes of PMSM drives. The proposed controller ensures fast and accurate dynamic response with an excellent steady state performance. Matlab/Simulink tool is used for this dynamic simulation study. The main contribution of this work is the implementation of the proposed controller on field programmable gate array (FPGA) hardware to drive the stepper motor. The driver is built on FPGA Spartan-3E Starter from Xilinx. Experimental results are presented to demonstrate the validity and effectiveness of the proposed control scheme.

  8. Static micro-array isolation, dynamic time series classification, capture and enumeration of spiked breast cancer cells in blood: the nanotube-CTC chip

    Science.gov (United States)

    Khosravi, Farhad; Trainor, Patrick J.; Lambert, Christopher; Kloecker, Goetz; Wickstrom, Eric; Rai, Shesh N.; Panchapakesan, Balaji

    2016-11-01

    We demonstrate the rapid and label-free capture of breast cancer cells spiked in blood using nanotube-antibody micro-arrays. 76-element single wall carbon nanotube arrays were manufactured using photo-lithography, metal deposition, and etching techniques. Anti-epithelial cell adhesion molecule (anti-EpCAM), Anti-human epithelial growth factor receptor 2 (anti-Her2) and non-specific IgG antibodies were functionalized to the surface of the nanotube devices using 1-pyrene-butanoic acid succinimidyl ester. Following device functionalization, blood spiked with SKBR3, MCF7 and MCF10A cells (100/1000 cells per 5 μl per device, 170 elements totaling 0.85 ml of whole blood) were adsorbed on to the nanotube device arrays. Electrical signatures were recorded from each device to screen the samples for differences in interaction (specific or non-specific) between samples and devices. A zone classification scheme enabled the classification of all 170 elements in a single map. A kernel-based statistical classifier for the ‘liquid biopsy’ was developed to create a predictive model based on dynamic time warping series to classify device electrical signals that corresponded to plain blood (control) or SKBR3 spiked blood (case) on anti-Her2 functionalized devices with ˜90% sensitivity, and 90% specificity in capture of 1000 SKBR3 breast cancer cells in blood using anti-Her2 functionalized devices. Screened devices that gave positive electrical signatures were confirmed using optical/confocal microscopy to hold spiked cancer cells. Confocal microscopic analysis of devices that were classified to hold spiked blood based on their electrical signatures confirmed the presence of cancer cells through staining for DAPI (nuclei), cytokeratin (cancer cells) and CD45 (hematologic cells) with single cell sensitivity. We report 55%-100% cancer cell capture yield depending on the active device area for blood adsorption with mean of 62% (˜12 500 captured off 20 000 spiked cells in 0.1 ml

  9. Modeling human learning involved in car driving

    OpenAIRE

    Wewerinke, P.H.

    1994-01-01

    In this paper, car driving is considered at the level of human tracking and maneuvering in the context of other traffic. A model analysis revealed the most salient features determining driving performance and safety. Learning car driving is modelled based on a system theoretical approach and based on a neural network approach. The aim of this research is to assess the relative merit of both approaches to describe human learning behavior in car driving specifically and in operating dynamic sys...

  10. Forces that Drive Nanoscale Self-assembly on Solid Surfaces

    International Nuclear Information System (INIS)

    Suo, Z.; Lu, W.

    2000-01-01

    Experimental evidence has accumulated in the recent decade that nanoscale patterns can self-assemble on solid surfaces. A two-component monolayer grown on a solid surface may separate into distinct phases. Sometimes the phases select sizes about 10 nm, and order into an array of stripes or disks. This paper reviews a model that accounts for these behaviors. Attention is focused on thermodynamic forces that drive the self-assembly. A double-welled, composition-dependent free energy drives phase separation. The phase boundary energy drives phase coarsening. The concentration-dependent surface stress drives phase refining. It is the competition between the coarsening and the refining that leads to size selection and spatial ordering. These thermodynamic forces are embodied in a nonlinear diffusion equation. Numerical simulations reveal rich dynamics of the pattern formation process. It is relatively fast for the phases to separate and select a uniform size, but exceedingly slow to order over a long distance, unless the symmetry is suitably broken

  11. Effect of ordered array of magnetic dots on the dynamics of Josephson vortices in stacked SNS Josephson junctions under DC and AC current

    Science.gov (United States)

    Berdiyorov, Golibjon R.; Savel'ev, Sergey; Kusmartsev, Feodor V.; Peeters, François M.

    2015-11-01

    We use the anisotropic time-dependent Ginzburg-Landau theory to investigate the effect of a square array of out-of-plane magnetic dots on the dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting (SNS) Josephson junctions in the presence of external DC and AC currents. Periodic pinning due to the magnetic dots distorts the triangular lattice of fluxons and results in the appearance of commensurability features in the current-voltage characteristics of the system. For the larger values of the magnetization, additional peaks appear in the voltage-time characteristics of the system due to the creation and annihilation of vortex-antivortex pairs. Peculiar changes in the response of the system to the applied current is found resulting in a "superradiant" vortex-flow state at large current values, where a rectangular lattice of moving vortices is formed. Synchronizing the motion of fluxons by adding a small ac component to the biasing dc current is realized. However, we found that synchronization becomes difficult for large magnetization of the dots due to the formation of vortex-antivortex pairs.

  12. Vegetation dynamics and its driving forces from climate change and human activities in the Three-River Source Region, China from 1982 to 2012

    International Nuclear Information System (INIS)

    Zhang, Ying; Zhang, Chaobin; Wang, Zhaoqi; Chen, Yizhao; Gang, Chengcheng; An, Ru; Li, Jianlong

    2016-01-01

    The Three-River Source Region (TRSR), a region with key importance to the ecological security of China, has undergone climate changes and a shift in human activities driven by a series of ecological restoration projects in recent decades. To reveal the spatiotemporal dynamics of vegetation dynamics and calculate the contributions of driving factors in the TRSR across different periods from 1982 to 2012, net primary productivity (NPP) estimated using the Carnegie–Ames–Stanford approach model was used to assess the status of vegetation. The actual effects of different climatic variation trends on interannual variation in NPP were analyzed. Furthermore, the relationships of NPP with different climate factors and human activities were analyzed quantitatively. Results showed the following: from 1982 to 2012, the average NPP in the study area was 187.37 g cm −2 yr −1 . The average NPP exhibited a fluctuation but presented a generally increasing trend over the 31-year study period, with an increase rate of 1.31 g cm −2 yr −2 . During the entire study period, the average contributions of temperature, precipitation, and solar radiation to NPP interannual variation over the entire region were 0.58, 0.73, and 0.09 g cm −2 yr −2 , respectively. Radiation was the climate factor with the greatest influence on NPP interannual variation. The factor that restricted NPP increase changed from temperature and radiation to precipitation. The average contributions of climate change and human activities to NPP interannual variation were 1.40 g cm −2 yr −2 and − 0.08 g cm −2 yr −2 , respectively. From 1982 to 2000, the general climate conditions were favorable to vegetation recovery, whereas human activities had a weaker negative impact on vegetation growth. From 2001 to 2012, climate conditions began to have a negative impact on vegetation growth, whereas human activities made a favorable impact on vegetation recovery. - Highlights: • Partitioned the

  13. Vegetation dynamics and its driving forces from climate change and human activities in the Three-River Source Region, China from 1982 to 2012

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying; Zhang, Chaobin; Wang, Zhaoqi; Chen, Yizhao; Gang, Chengcheng [School of Life Science, Nanjing University, Xianlin Road 163, Qixia District, Nanjing, 210046 (China); An, Ru [School of Earth Science and Engineering, Hohai University, Xikang Road 129, Nanjing, 210098 (China); Li, Jianlong, E-mail: lijianlongnju@163.com [School of Life Science, Nanjing University, Xianlin Road 163, Qixia District, Nanjing, 210046 (China)

    2016-09-01

    The Three-River Source Region (TRSR), a region with key importance to the ecological security of China, has undergone climate changes and a shift in human activities driven by a series of ecological restoration projects in recent decades. To reveal the spatiotemporal dynamics of vegetation dynamics and calculate the contributions of driving factors in the TRSR across different periods from 1982 to 2012, net primary productivity (NPP) estimated using the Carnegie–Ames–Stanford approach model was used to assess the status of vegetation. The actual effects of different climatic variation trends on interannual variation in NPP were analyzed. Furthermore, the relationships of NPP with different climate factors and human activities were analyzed quantitatively. Results showed the following: from 1982 to 2012, the average NPP in the study area was 187.37 g cm{sup −2} yr{sup −1}. The average NPP exhibited a fluctuation but presented a generally increasing trend over the 31-year study period, with an increase rate of 1.31 g cm{sup −2} yr{sup −2}. During the entire study period, the average contributions of temperature, precipitation, and solar radiation to NPP interannual variation over the entire region were 0.58, 0.73, and 0.09 g cm{sup −2} yr{sup −2}, respectively. Radiation was the climate factor with the greatest influence on NPP interannual variation. The factor that restricted NPP increase changed from temperature and radiation to precipitation. The average contributions of climate change and human activities to NPP interannual variation were 1.40 g cm{sup −2} yr{sup −2} and − 0.08 g cm{sup −2} yr{sup −2}, respectively. From 1982 to 2000, the general climate conditions were favorable to vegetation recovery, whereas human activities had a weaker negative impact on vegetation growth. From 2001 to 2012, climate conditions began to have a negative impact on vegetation growth, whereas human activities made a favorable impact on vegetation

  14. Studies of implosion processes of nested tungsten wire-array Z-pinch

    International Nuclear Information System (INIS)

    Ning Cheng; Ding Ning; Liu Quan; Yang Zhenhua

    2006-01-01

    Nested wire-array is a kind of promising structured-load because it can improve the quality of Z-pinch plasma and enhance the radiation power of X-ray source. Based on the zero-dimensional model, the assumption of wire-array collision, and the criterion of optimized load (maximal load kinetic energy), optimization of the typical nested wire-array as a load of Z machine at Sandia Laboratory was carried out. It was shown that the load has been basically optimized. The Z-pinch process of the typical load was numerically studied by means of one-dimensional three-temperature radiation magneto-hydrodynamics (RMHD) code. The obtained results reproduce the dynamic process of the Z-pinch and show the implosion trajectory of nested wire-array and the transfer process of drive current between the inner and outer array. The experimental and computational X-ray pulse was compared, and it was suggested that the assumption of wire-array collision was reasonable in nested wire-array Z-pinch at least for the current level of Z machine. (authors)

  15. Filter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  16. Fuel Consumption Reduction By Use Of Hybrid Drive Systems

    OpenAIRE

    Renken, Folker

    2015-01-01

    Vehicles with hybrid drive systems are characterized by their driving dynamics, their energy efficiency and their environment-friendliness especially. Dependent on the electrical power and the drive train structure these hybrid drives are grouped into different classes. Designations such as micro-hybrid, mild- hybrid, full-hybrid, serial-hybrid, serial/parallel-hybrid or power-split-hybrid reflect the large variance of these different drive train possibilities. In hybrid drive systems electro...

  17. Digital control of electric drives

    CERN Document Server

    Koziol, R; Szklarski, L

    1992-01-01

    The electromechanical systems employed in different branches of industry are utilized most often as drives of working machines which must be fed with electric energy in a continuous, periodic or even discrete way. Some of these machines operate at constant speed, others require wide and varying energy control. In many designs the synchronous cooperation of several electric drives is required in addition to the desired dynamic properties. For these reasons the control of the cooperation and dynamics of electromechanical systems requires the use of computers.This book adopts an unusual approach

  18. Dynamics Analysis of Frequency-Controlled Volumetric Hydraulic Drive with Power Supplied from the Built-in Pneumatic-Hydraulic Accumulator

    Directory of Open Access Journals (Sweden)

    Yu. Yu. Zuev

    2015-01-01

    Full Text Available The paper offers a volumetric hydraulic drive structure consisting of an unregulated pump, hydraulic motor, and energy accumulation block with pneumatic-hydraulic accumulator (PHA. Drive control is provided through frequency modification of current arriving at the asynchronous electric drive (AED from the frequency changer.The paper describes drive advantages when the energy accumulation block is set to allow power accumulation both from the AED and in recuperation regimes with moving outlet drive link with assisting loads. It offers simulation models and computer programmes to analyze a non-stationary movement of the outlet link of volumetric hydraulic drive with frequency control (VHD-FC with hydraulic motor power supplied from the PHA. The paper examines acceleration regimes of motor axis under different loads and presents PHA energy characteristics and algorithms to find desirable operational non-displaced and constructional accumulator capacities that provide motor outlet link acceleration up to the necessary speed. It presents graphs to show changing motor axis angle speed and PHA-displaced fluid volume as well as energy and PHA power during its discharge versus acceleration time of the motor axis. These dependences are obtained through varying different parameters of the system, namely: inertia, viscous friction, constant load moment, and volumetric displacement.The paper shows that decrease of inertia load and use of hydraulic motor with high volume constants result in the most essentially reduced acceleration time. Setting the PHA allows more than 2.5 times decreasing acceleration time of the motor axis. At the same time, because of the evidently complicated VHD-FC, taking decision on the sound PHA design and parameters must be based on the integration analysis of requirements. These requirements concern the VHD-FC reliability and performance in standard and failure modes as well as the technical-and-economic indexes and operation

  19. Electric drive design methodology

    CERN Document Server

    Jufer, Marcel

    2013-01-01

    An electric drive that is designed or adapted to a specific application must take into account all the elements of the chain of constituent elements in its use and deployment. In addition to the motor, the transmission, power electronics, control, sensors, and electrical protection systems must be taken into account. The motor and the transmission can be optimized and designed to obtain the best energy efficiency assessment, in particular for dynamic nodes. An inventory and a characterization of these various components is proposed as part of this book's examination and explanation

  20. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    The configuration of a tomographic array in which the object can rotate about its axis is described. The X-ray detector is a cylindrical screen perpendicular to the axis of rotation. The X-ray source has a line-shaped focus coinciding with the axis of rotation. The beam is fan-shaped with one side of this fan lying along the axis of rotation. The detector screen is placed inside an X-ray image multiplier tube

  1. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    A tomographic array with the following characteristics is described. An X-ray screen serving as detector is placed before a photomultiplier tube which itself is placed in front of a television camera connected to a set of image processors. The detector is concave towards the source and is replacable. Different images of the object are obtained simultaneously. Optical fibers and lenses are used for transmission within the system

  2. Singular formalism and admissible control of spacecraft with rotating flexible solar array

    Directory of Open Access Journals (Sweden)

    Lu Dongning

    2014-02-01

    Full Text Available This paper is concerned with the attitude control of a three-axis-stabilized spacecraft which consists of a central rigid body and a flexible sun-tracking solar array driven by a solar array drive assembly. Based on the linearization of the dynamics of the spacecraft and the modal identities about the flexible and rigid coupling matrices, the spacecraft attitude dynamics is reduced to a formally singular system with periodically varying parameters, which is quite different from a spacecraft with fixed appendages. In the framework of the singular control theory, the regularity and impulse-freeness of the singular system is analyzed and then admissible attitude controllers are designed by Lyapunov’s method. To improve the robustness against system uncertainties, an H∞ optimal control is designed by optimizing the H∞ norm of the system transfer function matrix. Comparative numerical experiments are performed to verify the theoretical results.

  3. Electric Drive Dynamic Thermal System Model for Advanced Vehicle Propulsion Technologies: Cooperative Research and Development Final Report, CRADA Number CRD-09-360

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, K. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-10-01

    Electric drive systems, which include electric machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the dependence of the U.S. transportation sector on petroleum. However, to penetrate the market, these electric drive technologies must enable vehicle solutions that are economically viable. The push to make critical electric drivesystems smaller, lighter, and more cost-effective brings respective challenges associated with heat removal and system efficiency. In addition, the wide application of electric drive systems to alternative propulsion technologies ranging from integrated starter generators, to hybrid electric vehicles, to full electric vehicles presents challenges in terms of sizing critical components andthermal management systems over a range of in-use operating conditions. This effort focused on developing a modular modeling methodology to enable multi-scale and multi-physics simulation capabilities leading to generic electric drive system models applicable to alternative vehicle propulsion configurations. The primary benefit for the National Renewable Energy Laboratory (NREL) is the abilityto define operating losses with the respective impact on component sizing, temperature, and thermal management at the component, subsystem, and system level. However, the flexible nature of the model also allows other uses related to evaluating the impacts of alternative component designs or control schemes depending on the interests of other parties.

  4. Kalman filter-based tracking of moving objects using linear ultrasonic sensor array for road vehicles

    Science.gov (United States)

    Li, Shengbo Eben; Li, Guofa; Yu, Jiaying; Liu, Chang; Cheng, Bo; Wang, Jianqiang; Li, Keqiang

    2018-01-01

    Detection and tracking of objects in the side-near-field has attracted much attention for the development of advanced driver assistance systems. This paper presents a cost-effective approach to track moving objects around vehicles using linearly arrayed ultrasonic sensors. To understand the detection characteristics of a single sensor, an empirical detection model was developed considering the shapes and surface materials of various detected objects. Eight sensors were arrayed linearly to expand the detection range for further application in traffic environment recognition. Two types of tracking algorithms, including an Extended Kalman filter (EKF) and an Unscented Kalman filter (UKF), for the sensor array were designed for dynamic object tracking. The ultrasonic sensor array was designed to have two types of fire sequences: mutual firing or serial firing. The effectiveness of the designed algorithms were verified in two typical driving scenarios: passing intersections with traffic sign poles or street lights, and overtaking another vehicle. Experimental results showed that both EKF and UKF had more precise tracking position and smaller RMSE (root mean square error) than a traditional triangular positioning method. The effectiveness also encourages the application of cost-effective ultrasonic sensors in the near-field environment perception in autonomous driving systems.

  5. The Influence of Immunization Route, Tissue Microenvironment, and Cytokine Cell Milieu on HIV-Specific CD8+ T Cells Measured Using Fluidigm Dynamic Arrays.

    Directory of Open Access Journals (Sweden)

    Shubhanshi Trivedi

    Full Text Available Thirty different genes including cytokines, chemokines, granzymes, perforin and specifically integrins were evaluated in Peyer's patch-KdGag197-205-specific CD8+ T cells (pools of 100 cells using Fluidigm 48.48 Dynamic arrays following three different prime-boost immunization strategies. Data revealed that the route of prime or the booster immunization differentially influenced the integrin expression profile on gut KdGag197-205-specific CD8+ T cells. Specifically, elevated numbers of integrin αE and αD expressing gut KdGag197-205-specific CD8+ T cells were detected following mucosal but not systemic priming. Also, αE/β7 and αD/β2 heterodimerization were more noticeable in an intranasal (i.n./i.n. vaccination setting compared to i.n./intramuscular (i.m or i.m./i.m. vaccinations. Moreover, in all vaccine groups tested α4 appeared to heterodimerize more closely with β7 then β1. Also MIP-1β, RANTES, CCR5, perforin and integrin α4 bio-markers were significantly elevated in i.n./i.m. and i.m./i.m. immunization groups compared to purely mucosal i.n./i.n. delivery. Furthermore, when wild type (WT BALB/c and IL-13 knockout (KO mice were immunized using i.n./i.m. strategy, MIP-1α, MIP-1β, RANTES, integrins α4, β1 and β7 mRNA expression levels were found to be significantly different, in mucosal verses systemic KdGag197-205-specific CD8+ T cells. Interestingly, the numbers of gut KdGag197-205-specific CD8+ T cells expressing gut-homing markers α4β7 and CCR9 protein were also significantly elevated in IL-13 KO compared to WT control. Collectively, our findings further corroborate that the route of vaccine delivery, tissue microenvironment and IL-13 depleted cytokine milieu can significantly alter the antigen-specific CD8+ T cell gene expression profiles and in turn modulate their functional avidities as well as homing capabilities.

  6. Thermodynamic driving force for rafting in superalloys

    CSIR Research Space (South Africa)

    Nabarro, FRN

    1996-08-01

    Full Text Available Eshelby’s energy-momentum tensor is used to provide an analytical expression for the driving force for rafting in the elastic regime in a super alloy with a high volume fraction of gamma'. The structure is modeled as a simple cubic array of gamma...

  7. Vortex Avalanches with Periodic Arrays of Pinning Sites

    Science.gov (United States)

    Abbas, J.; Heckel, T.; Kakalios, J.

    2001-03-01

    Numerical simulations by Nori and co-workers of dynamical phase transitions for magnetic vortices in type II superconductors when the defects which act as pinning sites are arranged in a periodic array have found a dramatic non-linear relationship between vortex voltage and driving current.2,4 In order to experimentally test the predictions of these simulations, a macroscopic physical analog of an array of flux vortices in the presense of an ordered lattice of pinning sites has been constructed. This simple table-top experimental system consists of conventional household magnets, arranged in an ordered grid (serving as the lattice of fixed pinning centers). A plexiglass sheet is positioned above these fixed magnets, and another collection of magnets (representing the magnetic flux vortices), oriented so that they are attracted to the fixed magnets are placed on top of the sheet. The entire apparatus is then tilted to a given angle (the analog of the driving voltage) and the velocity of the avalanching magnets is recorded using the induced voltage in a pick-up coil. By varying the ratio of movable magnets to fixed pinning magnets, the filling fraction can be adjusted, as can the pinning strength, by adjusting the separation of the plexiglass sheet between the fixed and movable magnets. The velocity of the avalanching magnets as the filling fraction is varied displays a jamming transition, with a non-trivial dependence on the pinning strength of the lattice of fixed magnets below the sheet.

  8. Simulation modes of movement the drive rollers of suspension of conveyor with suspended belt and distributed drive

    Directory of Open Access Journals (Sweden)

    Lagerev A.V.

    2016-03-01

    Full Text Available Mathematical model of conveyor with suspended belt and distributed drive which allows to simulate the dynamics of suspension at various modes of movement of the drive roller is developed. The modeling results are presented in the article.

  9. Safe driving for teens

    Science.gov (United States)

    Driving and teenagers; Teens and safe driving; Automobile safety - teenage drivers ... MAKE A COMMITTMENT TO SAFETY Teens also need to commit to being safe and responsible drivers in order to improve the odds in their favor. Reckless driving ...

  10. A study on the effects of fatigue driving and drunk driving on drivers' physical characteristics.

    Science.gov (United States)

    Zhang, Xingjian; Zhao, Xiaohua; Du, Hongji; Rong, Jian

    2014-01-01

    The purpose of this study was to analyze the effects of fatigue driving and drunk driving on drivers' physical characteristics; to analyze the differences in drivers' physical characteristics affected by different kinds of fatigue; and to compare the differences in the effects of the 2 driving states, fatigue driving and drunk driving. Twenty-five participants' physical characteristics were collected under 5 controlled situations: normal, tired driving, drowsy driving, drowsiness + tired driving, and drunk driving. In this article, fatigue driving refers to tiredness and drowsiness and includes 3 situations: tired driving, drowsy driving, and drowsiness + tired driving. The drivers' physical characteristics were measured in terms of 9 parameters: systolic blood pressure (SBP), heart rate (HR), eyesight, dynamic visual acuity (DVA), time for dark adaption (TDA), reaction time to sound (RTS), reaction time to light (RTL), deviation of depth perception (DDP), and time deviation of speed anticipation (TDSA). They were analyzed using analysis of variance (ANOVA) with repeated measures. Binary logistical regression analysis was used to explain the relationship between drivers' physical characteristics and the two driving states. Most of the drivers' physical characteristic parameters were found to be significantly different under the influence of different situations. Four indicators are significantly affected by fatigue driving during deep fatigue (in decreasing order of influence): HR, RTL, SBP and RTS. HR and RTL are significant in the logistical regression model of the drowsiness + tired driving situation and normal situations. Six indicators of the drivers' physical characteristics are significantly affected by drunk driving (in decreasing order of influence): SBP, RTL, DDP, eyesight, RTS, and TDSA. SBP and DDP have a significant effect in the logistical regression model of the drunk driving situation and the normal situation. Both fatigue driving and drunk driving

  11. Driving Performance Under Alcohol in Simulated Representative Driving Tasks

    Science.gov (United States)

    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 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

  12. The dynamics driving the invasion of Brassica nigra and Foeniculum vulgare in California : the interaction of competition, herbivory, and seed source

    OpenAIRE

    Hanna, Victoria Anderson

    2014-01-01

    Invasive species are highly detrimental to economies and to ecosystems. To counter the negative effects of invasive plant species, a better understanding of the mechanisms driving their dominance and success is necessary. The factors of competition, herbivory, and seed source were examined using two plant species invasive to California- Brassica nigra and Foeniculum vulgare. It was found that B. nigra is affected by each factor individually but not by any interactions between the factors. F. ...

  13. Spaceborne Processor Array

    Science.gov (United States)

    Chow, Edward T.; Schatzel, Donald V.; Whitaker, William D.; Sterling, Thomas

    2008-01-01

    A Spaceborne Processor Array in Multifunctional Structure (SPAMS) can lower the total mass of the electronic and structural overhead of spacecraft, resulting in reduced launch costs, while increasing the science return through dynamic onboard computing. SPAMS integrates the multifunctional structure (MFS) and the Gilgamesh Memory, Intelligence, and Network Device (MIND) multi-core in-memory computer architecture into a single-system super-architecture. This transforms every inch of a spacecraft into a sharable, interconnected, smart computing element to increase computing performance while simultaneously reducing mass. The MIND in-memory architecture provides a foundation for high-performance, low-power, and fault-tolerant computing. The MIND chip has an internal structure that includes memory, processing, and communication functionality. The Gilgamesh is a scalable system comprising multiple MIND chips interconnected to operate as a single, tightly coupled, parallel computer. The array of MIND components shares a global, virtual name space for program variables and tasks that are allocated at run time to the distributed physical memory and processing resources. Individual processor- memory nodes can be activated or powered down at run time to provide active power management and to configure around faults. A SPAMS system is comprised of a distributed Gilgamesh array built into MFS, interfaces into instrument and communication subsystems, a mass storage interface, and a radiation-hardened flight computer.

  14. Fast wave current drive above the slow wave density limit

    International Nuclear Information System (INIS)

    McWilliams, R.; Sheehan, D.P.; Wolf, N.S.; Edrich, D.

    1989-01-01

    Fast wave and slow wave current drive near the mean gyrofrequency were compared in the Irvine Torus using distinct phased array antennae of similar principal wavelengths, frequencies, and input powers. The slow wave current drive density limit was measured for 50ω ci ≤ω≤500ω ci and found to agree with trends in tokamaks. Fast wave current drive was observed at densities up to the operating limit of the torus, demonstrably above the slow wave density limit

  15. Distress tolerance as a predictor of risky and aggressive driving.

    Science.gov (United States)

    Beck, Kenneth H; Ali, Bina; Daughters, Stacey B

    2014-01-01

    The purpose of this investigation was to determine the relationship between distress tolerance and risky and aggressive driving. Distress tolerance, defined as an individual's capability to experience and endure negative emotional states, was hypothesized to be related negatively to aggressive driving and risky driving. An anonymous, web-based survey of 769 college students was conducted at a large East Coast university. After controlling for age, gender, race, ethnicity, year in school, grade point average, and driving frequency, distress tolerance was significantly inversely related to reported risky driving and aggressive driving. College drivers who have a diminished capacity to endure frustration without experiencing negative emotional states (i.e., low distress tolerance) tend to drive aggressively and in a risky manner. Traditional deterrence-based approaches to highway safety may benefit from inclusion of a wider array of prevention strategies that focus on emotion regulation while driving.

  16. Fuzzy Logic-Based Perturb and Observe Algorithm with Variable Step of a Reference Voltage for Solar Permanent Magnet Synchronous Motor Drive System Fed by Direct-Connected Photovoltaic Array

    Directory of Open Access Journals (Sweden)

    Mohamed Redha Rezoug

    2018-02-01

    Full Text Available Photovoltaic pumping is considered to be the most used application amongst other photovoltaic energy applications in isolated sites. This technology is developing with a slow progression to allow the photovoltaic system to operate at its maximum power. This work introduces the modified algorithm which is a perturb and observe (P&O type to overcome the limitations of the conventional P&O algorithm and increase its global performance in abrupt weather condition changes. The most significant conventional P&O algorithm restriction is the difficulty faced when choosing the variable step of the reference voltage value, a good compromise between the swift dynamic response and the stability in the steady state. To adjust the step reference voltage according to the location of the operating point of the maximum power point (MPP, a fuzzy logic controller (FLC block adapted to the P&O algorithm is used. This allows the improvement of the tracking pace and the steady state oscillation elimination. The suggested method was evaluated by simulation using MATLAB/SimPowerSystems blocks and compared to the classical P&O under different irradiation levels. The results obtained show the effectiveness of the technique proposed and its capacity for the practical and efficient tracking of maximum power.

  17. Simulation and Analysis of Chain Drive Systems

    DEFF Research Database (Denmark)

    Pedersen, Sine Leergaard

    The subject of this thesis is simulation and analysis of large roller chain drive systems, such as e.g. used in marine diesel engines. The aim of developing a chain drive simulation program is to analyse dynamic phenomena of chain drive systems and investigate different design changes...... to the systems, in order to remove unwanted phenomena. Such a computer program can, when properly validated, be used as an alternative to or in combination with physical experiments. Prior investigations in this area have been done with a focus on smaller chains in high speed chain drives. For large low speed...... systems other phenomena occur and therefore, a specific model of the marine engine chain drive is of interest. The research objective of the work presented in this thesis is to contribute with a novel theoretical basis for the analysis of chain drive systems, by posing and validating different...

  18. Transverse commensurability effect for vortices on periodic pinning arrays

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory

    2008-01-01

    Using computer simulations, we demonstrate a type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex density, there is a series of broad maxima in the transverse critical depinning force that do not fall at the matching fields where the number of vortices equals an integer multiple of the number of pinning sites. The commensurability effects are associated with dynamical states in which evenly spaced structures consisting of one or more moving rows of vortices form between rows of pinning sites. Remarkably, the critical transverse depinning force can be more than an order of magnitude larger than the longitudinal depinning force.

  19. Terabyte IDE RAID-5 Disk Arrays

    Energy Technology Data Exchange (ETDEWEB)

    David A. Sanders et al.

    2003-09-30

    High energy physics experiments are currently recording large amounts of data and in a few years will be recording prodigious quantities of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that exploit recent developments in commodity hardware. We report on tests of redundant arrays of integrated drive electronics (IDE) disk drives for use in offline high energy physics data analysis. IDE redundant array of inexpensive disks (RAID) prices now are less than the cost per terabyte of million-dollar tape robots! The arrays can be scaled to sizes affordable to institutions without robots and used when fast random access at low cost is important.

  20. Performance of solar photovoltaic array fed water pumping system ...

    African Journals Online (AJOL)

    DR OKE

    This paper discusses the design and performance analysis of a solar photovoltaic (SPV) array fed water pumping system utilizing a special class of highly rugged machine with simple drive system called switched reluctance motor (SRM) drive. The proposed method of water pumping system also provides the cost effective ...

  1. Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM

    Science.gov (United States)

    Ding, Ning; Zhang, Yang; Xiao, Delong; Wu, Jiming; Huang, Jun; Yin, Li; Sun, Shunkai; Xue, Chuang; Dai, Zihuan; Ning, Cheng; Shu, Xiaojian; Wang, Jianguo; Li, Hua

    2014-12-01

    Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosion phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the "Qiangguang I" facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire-array

  2. Temperature drives abundance fluctuations, but spatial dynamics is constrained by landscape configuration: Implications for climate-driven range shift in a butterfly.

    Science.gov (United States)

    Fourcade, Yoan; Ranius, Thomas; Öckinger, Erik

    2017-10-01

    Prediction of species distributions in an altered climate requires knowledge on how global- and local-scale factors interact to limit their current distributions. Such knowledge can be gained through studies of spatial population dynamics at climatic range margins. Here, using a butterfly (Pyrgus armoricanus) as model species, we first predicted based on species distribution modelling that its climatically suitable habitats currently extend north of its realized range. Projecting the model into scenarios of future climate, we showed that the distribution of climatically suitable habitats may shift northward by an additional 400 km in the future. Second, we used a 13-year monitoring dataset including the majority of all habitat patches at the species northern range margin to assess the synergetic impact of temperature fluctuations and spatial distribution of habitat, microclimatic conditions and habitat quality, on abundance and colonization-extinction dynamics. The fluctuation in abundance between years was almost entirely determined by the variation in temperature during the species larval development. In contrast, colonization and extinction dynamics were better explained by patch area, between-patch connectivity and host plant density. This suggests that the response of the species to future climate change may be limited by future land use and how its host plants respond to climate change. It is, thus, probable that dispersal limitation will prevent P. armoricanus from reaching its potential future distribution. We argue that models of range dynamics should consider the factors influencing metapopulation dynamics, especially at the range edges, and not only broad-scale climate. It includes factors acting at the scale of habitat patches such as habitat quality and microclimate and landscape-scale factors such as the spatial configuration of potentially suitable patches. Knowledge of population dynamics under various environmental conditions, and the

  3. Terahertz superconducting plasmonic hole array.

    Science.gov (United States)

    Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Gu, Jianqiang; Xing, Qirong; Wu, Judy; Zhang, Weili

    2010-11-01

    We demonstrate a superconductor array of subwavelength holes with active thermal control over the resonant transmission induced by surface plasmon polaritons. The array was lithographically fabricated on a high-temperature yttrium barium copper oxide superconductor and characterized by terahertz time-domain spectroscopy. We observe a clear transition from a virtual excitation of the surface plasmon mode to a real surface plasmon mode. The highly controllable superconducting plasmonic crystals may find promising applications in the design of low-loss, large- dynamic-range amplitude modulation and surface-plasmon-based terahertz devices.

  4. Coupling in reflector arrays

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1968-01-01

    In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present communic......In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present...

  5. Two decades of climate driving the dynamics of functional and taxonomic diversity of a tropical small mammal community in western Mexico.

    Directory of Open Access Journals (Sweden)

    Edgard David Mason-Romo

    Full Text Available Understanding the effects of global climate disruption on biodiversity is important to future conservation efforts. While taxonomic diversity is widely studied, functional diversity of plants, and recently animals, is receiving increasing attention. Most studies of mammals are short-term, focus on temperate habitats, and rely on traits described in the literature rather than generating traits from observations. Unlike previous studies, this long-term field study assessed the factors driving the functional and taxonomic diversity of small-mammal assemblages in dry tropical forests using both traits recorded from literature and a demographic database. We assessed the drivers (abundance and biomass, temperature and rainfall of taxonomic richness and functional diversity for two rain-driven seasons in two adjacent but distinct forests-upland and lowland (arroyo or riparian forests. Our analysis found that rainfall, both seasonal and atypical, was the primary factor driving functional and taxonomic diversity of small-mammal assemblages. Functional responses differed between the two types of forests, however, with effects being stronger in the harsher conditions of the upland forests than in the less severe conditions prevailing in the arroyo (riparian forest. The latter also supports a richer, more diverse, and more stable small-mammal assemblage. These findings highlight the importance of climate to tropical biological diversity, as extreme climate events (hurricanes, droughts and floods and disruption of rainfall patterns were shown to decrease biodiversity. They also support the need to preserve these habitats, as their high taxonomic diversity and functional redundancy makes them resilient against global climate disruption and local extreme events. Tropical dry forests constitute a potential reservoir for biodiversity and the ecosystem services they provide. Unfortunately, these forests are among the most endangered terrestrial ecosystems because

  6. Two decades of climate driving the dynamics of functional and taxonomic diversity of a tropical small mammal community in western Mexico

    Science.gov (United States)

    2017-01-01

    Understanding the effects of global climate disruption on biodiversity is important to future conservation efforts. While taxonomic diversity is widely studied, functional diversity of plants, and recently animals, is receiving increasing attention. Most studies of mammals are short-term, focus on temperate habitats, and rely on traits described in the literature rather than generating traits from observations. Unlike previous studies, this long-term field study assessed the factors driving the functional and taxonomic diversity of small-mammal assemblages in dry tropical forests using both traits recorded from literature and a demographic database. We assessed the drivers (abundance and biomass, temperature and rainfall) of taxonomic richness and functional diversity for two rain-driven seasons in two adjacent but distinct forests—upland and lowland (arroyo or riparian) forests. Our analysis found that rainfall, both seasonal and atypical, was the primary factor driving functional and taxonomic diversity of small-mammal assemblages. Functional responses differed between the two types of forests, however, with effects being stronger in the harsher conditions of the upland forests than in the less severe conditions prevailing in the arroyo (riparian) forest. The latter also supports a richer, more diverse, and more stable small-mammal assemblage. These findings highlight the importance of climate to tropical biological diversity, as extreme climate events (hurricanes, droughts and floods) and disruption of rainfall patterns were shown to decrease biodiversity. They also support the need to preserve these habitats, as their high taxonomic diversity and functional redundancy makes them resilient against global climate disruption and local extreme events. Tropical dry forests constitute a potential reservoir for biodiversity and the ecosystem services they provide. Unfortunately, these forests are among the most endangered terrestrial ecosystems because of

  7. Two decades of climate driving the dynamics of functional and taxonomic diversity of a tropical small mammal community in western Mexico.

    Science.gov (United States)

    Mason-Romo, Edgard David; Farías, Ariel A; Ceballos, Gerardo

    2017-01-01

    Understanding the effects of global climate disruption on biodiversity is important to future conservation efforts. While taxonomic diversity is widely studied, functional diversity of plants, and recently animals, is receiving increasing attention. Most studies of mammals are short-term, focus on temperate habitats, and rely on traits described in the literature rather than generating traits from observations. Unlike previous studies, this long-term field study assessed the factors driving the functional and taxonomic diversity of small-mammal assemblages in dry tropical forests using both traits recorded from literature and a demographic database. We assessed the drivers (abundance and biomass, temperature and rainfall) of taxonomic richness and functional diversity for two rain-driven seasons in two adjacent but distinct forests-upland and lowland (arroyo or riparian) forests. Our analysis found that rainfall, both seasonal and atypical, was the primary factor driving functional and taxonomic diversity of small-mammal assemblages. Functional responses differed between the two types of forests, however, with effects being stronger in the harsher conditions of the upland forests than in the less severe conditions prevailing in the arroyo (riparian) forest. The latter also supports a richer, more diverse, and more stable small-mammal assemblage. These findings highlight the importance of climate to tropical biological diversity, as extreme climate events (hurricanes, droughts and floods) and disruption of rainfall patterns were shown to decrease biodiversity. They also support the need to preserve these habitats, as their high taxonomic diversity and functional redundancy makes them resilient against global climate disruption and local extreme events. Tropical dry forests constitute a potential reservoir for biodiversity and the ecosystem services they provide. Unfortunately, these forests are among the most endangered terrestrial ecosystems because of

  8. Antenna Arrays and Automotive Applications

    CERN Document Server

    Rabinovich, Victor

    2013-01-01

    This book throws a lifeline to designers wading through mounds of antenna array patents looking for the most suitable systems for their projects. Drastically reducing the research time required to locate solutions to the latest challenges in automotive communications, it sorts and systematizes material on cutting-edge antenna arrays that feature multi-element communication systems with enormous potential for the automotive industry. These new systems promise to make driving safer and more efficient, opening up myriad applications, including vehicle-to-vehicle traffic that prevents collisions, automatic toll collection, vehicle location and fine-tuning for cruise control systems. This book’s exhaustive coverage begins with currently deployed systems, frequency ranges and key parameters. It proceeds to examine system geometry, analog and digital beam steering technology (including "smart" beams formed in noisy environments), maximizing signal-to-noise ratios, miniaturization, and base station technology that ...

  9. Unitary deformations of counterdiabatic driving

    Science.gov (United States)

    Takahashi, Kazutaka

    2015-04-01

    We study a deformation of the counterdiabatic-driving Hamiltonian as a systematic strategy for an adiabatic control of quantum states. Using a unitary transformation, we design a convenient form of the driver Hamiltonian. We apply the method to a particle in a confining potential and discrete systems to find explicit forms of the Hamiltonian and discuss the general properties. The method is derived by using the quantum brachistochrone equation, which shows the existence of a nontrivial dynamical invariant in the deformed system.

  10. A Dynamic Developmental Link between Verbal Comprehension-Knowledge (Gc) and Reading Comprehension: Verbal Comprehension-Knowledge Drives Positive Change in Reading Comprehension

    Science.gov (United States)

    Reynolds, Matthew R.; Turek, Joshua J.

    2012-01-01

    Intelligence and general academic achievement have a well-established relation, but the interrelated development of the two constructs over time is less well-known. In this study, the dynamic developmental relation between verbal comprehension-knowledge (Gc) and reading comprehension was examined by applying bivariate dual change score models…

  11. Improvements of Piezo-Actuated Stick–Slip Micro-Drives: Modeling and Driving Waveform

    Directory of Open Access Journals (Sweden)

    Xuan-Ha Nguyen

    2018-02-01

    Full Text Available Modeling and waveform optimization are important research topics for piezo-actuated stick–slip micro-drives. In this paper, the dynamics of piezo-actuated stick–slip micro-drives (PASSMDs are theoretically investigated. We introduce an extended model taking the dynamics of the piezo actuators into account. The model combines the whole macroscopic movement of the drive’s runner and actuators and the microscopic behavior of the frictional contacts in a hybrid dynamic simulation. The macroscopic movements are described via Newtonian mechanics, while the microscopic behavior is computed using the method of dimensionality reduction. Two important characteristics of the drive, the critical actuation amplitude and the force generation, are systematically analyzed. The numerical simulation results show a fine agreement with experimental data of the previously published work. The critical actuation amplitude is found to depend on the behavior of the guiding contacts, the dynamics of the actuators and their interaction. Furthermore, a novel driving waveform, which allows us to increase the operational velocity for the drive, is proposed. The waveform is derived by exploiting micro-vibration and considering the dynamic contact status. Simulation results show that the average velocity of the drive is heightened by about 15 % . The performance of the drive is therefore improved.

  12. Dementia and driving

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000028.htm Dementia and driving To use the sharing features on ... please enable JavaScript. If your loved one has dementia , deciding when they can no longer drive may ...

  13. Control rod drives

    International Nuclear Information System (INIS)

    Shimano, Kunio; Nakamura, Akira; Mizuguchi, Koji; Sakai, Kazuhito; Mitsui, Hisayasu.

    1994-01-01

    The present invention concerns upper-built-in type control rod drives of a BWR type reactor. Namely, high temperature linear motor driving type control rod drives are disposed in an upper space of the reactor pressure vessel, which generates electromagnetic power. In usual driving of control rods, driving shafts connected with control rods by a high temperature linear motor driving system comprising a driving shaft having an iron core inserted therein and electromagnetic coils is vertically moved to insert/withdraw the control rods to and from the reactor core. Upon occurrence of reactor scram, electric power source is interrupted, and the control rods are rapidly inserted to the reactor core. According to the present invention, since the control rod drives are disposed in the space above the reactor pressure vessel, pipelines or equipments passing through the bottom of the reactor pressure vessel can be saved. As a result, operation for maintenance and inspection is facilitated. (I.S.)

  14. Gear bearing drive

    Science.gov (United States)

    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.

  15. Simple Driving Techniques

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    2002-01-01

    -like language. Our aim is to extract a simple notion of driving and show that even in this tamed form it has much of the power of more general notions of driving. Our driving technique may be used to simplify functional programs which use function composition and will often be able to remove intermediate data...

  16. The Importance of Permafrost Thaw, Fire and Logging Disturbances as Driving Factors of Historical and Projected Carbon Dynamics in Alaskan Ecosystems

    Science.gov (United States)

    Genet, H.; Zhang, Y.; McGuire, A. D.; He, Y.; Johnson, K. D.; D'Amore, D. V.; Zhou, X.; Bennett, A.; Breen, A. L.; Biles, F. E.; Bliss, N. B.; Euskirchen, E. S.; Kurkowski, T. A.; Pastick, N.; Rupp, S. T.; Wylie, B. K.; Zhu, Z.; Zhuang, Q.

    2014-12-01

    Carbon dynamics of natural ecosystems are influenced by disturbance regimes of various frequencies and magnitudes. With global change, these disturbances are projected to increase in frequency and/or magnitude and may have significant effects on future net carbon balance, especially in high latitude ecosystems where carbon stocks are among the largest on Earth and climate change is substantial. In Alaska, permafrost degradation and fire in the boreal and arctic regions and logging in the southern coastal region are the main disturbances that affect ecosystems. Large uncertainties related to the effects of these disturbances on the capacity of these regions to store carbon still exist mainly due to difficulty in representing permafrost degradation in current ecosystem models. We ran the Terrestrial Ecosystem Model (TEM), which explicitly simulates the carbon cycle and permafrost dynamics, coupled with a disturbance model (the Alaska Frame Based Ecosystem Code, ALFRESCO) to assess the relative importance of permafrost thaw, wildfire, and forest management on historical and projected carbon balance and carbon stocks in Alaska, from 1950 to 2100, at a 1-km resolution. Our simulations showed that the increase in plant productivity in response to warming in boreal and arctic regions is offset by soil carbon loss due to permafrost degradation and wildfire combustion during both historical and future simulations. Fire disturbances act as a catalyst accelerating permafrost degradation and associated soil carbon loss. In addition, our preliminary results for south coastal regions of Alaska indicate that logging of second growth forests could influence carbon dynamics in that region. Overall, these results have implications for land management strategies and illustrate the importance of taking into account multiple types of disturbance regimes in ecosystem models for Alaska.

  17. Modeling the dynamics of a non-limited and a self-limited gene drive system in structured Aedes aegypti populations.

    Directory of Open Access Journals (Sweden)

    Mathieu Legros

    Full Text Available Recently there have been significant advances in research on genetic strategies to control populations of disease-vectoring insects. Some of these strategies use the gene drive properties of selfish genetic elements to spread physically linked anti-pathogen genes into local vector populations. Because of the potential of these selfish elements to spread through populations, control approaches based on these strategies must be carefully evaluated to ensure a balance between the desirable spread of the refractoriness-conferring genetic cargo and the avoidance of potentially unwanted outcomes such as spread to non-target populations. There is also a need to develop better estimates of the economics of such releases. We present here an evaluation of two such strategies using a biologically realistic mathematical model that simulates the resident Aedes aegypti mosquito population of Iquitos, Peru. One strategy uses the selfish element Medea, a non-limited element that could permanently spread over a large geographic area; the other strategy relies on Killer-Rescue genetic constructs, and has been predicted to have limited spatial and temporal spread. We simulate various operational approaches for deploying these genetic strategies, and quantify the optimal number of released transgenic mosquitoes needed to achieve definitive spread of Medea-linked genes and/or high frequencies of Killer-Rescue-associated elements. We show that for both strategies the most efficient approach for achieving spread of anti-pathogen genes within three years is generally to release adults of both sexes in multiple releases over time. Even though females in these releases should not transmit disease, there could be public concern over such releases, making the less efficient male-only release more practical. This study provides guidelines for operational approaches to population replacement genetic strategies, as well as illustrates the use of detailed spatial models to

  18. High performance AC drives

    CERN Document Server

    Ahmad, Mukhtar

    2010-01-01

    This book presents a comprehensive view of high performance ac drives. It may be considered as both a text book for graduate students and as an up-to-date monograph. It may also be used by R & D professionals involved in the improvement of performance of drives in the industries. The book will also be beneficial to the researchers pursuing work on multiphase drives as well as sensorless and direct torque control of electric drives since up-to date references in these topics are provided. It will also provide few examples of modeling, analysis and control of electric drives using MATLAB/SIMULIN

  19. A dynamic developmental link between verbal comprehension-knowledge (Gc) and reading comprehension: verbal comprehension-knowledge drives positive change in reading comprehension.

    Science.gov (United States)

    Reynolds, Matthew R; Turek, Joshua J

    2012-12-01

    Intelligence and general academic achievement have a well-established relation, but the interrelated development of the two constructs over time is less well-known. In this study, the dynamic developmental relation between verbal comprehension-knowledge (Gc) and reading comprehension was examined by applying bivariate dual change score models (McArdle, 2009) to longitudinal data collected from children aged 9 through 15 who were part of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (NICHD SECCYD). A unidirectional dynamic link was found in which higher levels of prior Gc led to increased positive change in reading comprehension scores. This unidirectional link was not altered by including intelligence measured at 24-months, SES, sex, basic reading, and reading volume as time-invariant covariates. Gc is a leading indicator of reading comprehension and should be considered when developing and monitoring long-term reading comprehension interventions for children. Copyright © 2012 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  20. CoGNaC: A Chaste Plugin for the Multiscale Simulation of Gene Regulatory Networks Driving the Spatial Dynamics of Tissues and Cancer.

    Science.gov (United States)

    Rubinacci, Simone; Graudenzi, Alex; Caravagna, Giulio; Mauri, Giancarlo; Osborne, James; Pitt-Francis, Joe; Antoniotti, Marco

    2015-01-01

    We introduce a Chaste plugin for the generation and the simulation of Gene Regulatory Networks (GRNs) in multiscale models of multicellular systems. Chaste is a widely used and versatile computational framework for the multiscale modeling and simulation of multicellular biological systems. The plugin, named CoGNaC (Chaste and Gene Networks for Cancer), allows the linking of the regulatory dynamics to key properties of the cell cycle and of the differentiation process in populations of cells, which can subsequently be modeled using different spatial modeling scenarios. The approach of CoGNaC focuses on the emergent dynamical behavior of gene networks, in terms of gene activation patterns characterizing the different cellular phenotypes of real cells and, especially, on the overall robustness to perturbations and biological noise. The integration of this approach within Chaste's modular simulation framework provides a powerful tool to model multicellular systems, possibly allowing for the formulation of novel hypotheses on gene regulation, cell differentiation, and, in particular, cancer emergence and development. In order to demonstrate the usefulness of CoGNaC over a range of modeling paradigms, two example applications are presented. The first of these concerns the characterization of the gene activation patterns of human T-helper cells. The second example is a multiscale simulation of a simplified intestinal crypt, in which, given certain conditions, tumor cells can emerge and colonize the tissue.

  1. Working with arrays of inexpensive EIDE disk drives

    International Nuclear Information System (INIS)

    Sanders, D.; Riley, C.; Cremaldi, L.; Summers, D.; Petravick, D.

    2000-01-01

    In today's marketplace, the cost per Terabyte of disks with EIDE interfaces is about a third that of disks with SCSI. Hence, three times as many particle physics events could be put online with EIDE. The modern EIDE interface includes many of the performance features that appeared earlier in SCSI. EIDE bus speeds approach 33 Megabytes/s and need only be shared between two disks rather than seven disks. The interal I/O rate of very fast (and expensive) SCSI disks is only 50% greater than EIDE disks. Hence, two EIDE disks whose combined cost is much less than one very fast SCSI disk can actually give more data throughput due to the advantage of multiple spindles and head actuators. The authors explore the use of 12 and 16 Gigabyte EIDE disks with motherboard and PCI bus card interfaces on a number of operating systems and CPUs. These include Red Hat Linux and Windows 95/98 on a Pentium, MacOS and Apple's Rhapsody/NeXT/UNIX on a PowerPC, and Sun Solaris on a UltraSparc 10 workstation

  2. Energetic Optimal Control Of Adjustable Drive Systems

    Directory of Open Access Journals (Sweden)

    Ion BIVOL

    2002-12-01

    Full Text Available n the paper is developed a new control strategy for the adjustable speed drives. The strategy consists in the energetic optimal control of the dynamic regimes as starting, stopping and reversing. The main developed problems: formulation of energetic optimal problem, solution, experimental results via simulation and some considerations concerning the use of the control. The optimal developed solution can be applied for the both AC and DC drives, but only for linear systems.

  3. The influence of the cathode array and the pressure variations on the current sheath dynamics of a small plasma focus device in the presence of an axial magnetic probe

    Science.gov (United States)

    Piriaei, D.; Javadi, S.; Mahabadi, T. D.; Yousefi, H. R.; Salar Elahi, A.; Ghoranneviss, M.

    2017-04-01

    In this research, the influence of the cathode array and the pressure variations on the current sheath dynamics of a small plasma focus device (450 J) was investigated. For this purpose, the signals of an axial magnetic probe for two different gases (argon and nitrogen) were studied. The magnetic probe signals showed the slower movement of the current sheath layer when the number of cathode rods decreased. This was related to the increase in the circuit inductance, which caused the longer discharge time of the capacitor bank followed by the creation of runaway electrons. These electrons in turn produced the impurities that led to the appearance of the instabilities inside the plasma. On the other hand, in order to investigate the effect of the cathode array variation on the instabilities produced inside the plasma, the wavelet technique was used. With the aid of frequency analysis, this technique showed the increase in these instabilities, which was due to the non-uniform formation of the current sheath layer during the breakdown phase, and finally, the higher values of the pressure caused the slower movement of the current sheath due to the inverse relation of the current sheath velocity to the square root of the pressure.

  4. Dynamics Change of Honghu Lake's Water Surface Area and Its Driving Force Analysis Based on Remote Sensing Technique and TOPMODEL model

    International Nuclear Information System (INIS)

    Wen, X; Cao, B; Shen, S; Hu, D; Tang, X

    2014-01-01

    Honghu Lake is the largest freshwater lake in the Hubei Province of China. This paper introduces a remote sensing approach to monitor the lake's water surface area dynamics over the last 40 years by using multi-temporal remote sensing imagery including Landsat and HJ-1. Meanwhile, the daily precipitation and evaporation data provided by Honghu meteorological station since 1970s were also collected and used to analyze the influence of climate change factors. The typical situation for precipitation was selected as an input into the TOPMODEL model to simulate the hydrological process in Honghu Lake. The simulation result with the water surface area extracted from remote sensing imagery was analyzed. This experiment shows the precipitation and timing of precipitation effects changes in the lake with remote sensing data and it showed the potential of using TOPMODEL model to analyze the combined hydrological process in Honghu Lake

  5. Spreading of liquid drop on superhydrophilic micropillar array

    Science.gov (United States)

    Kim, Seong Jin; Moon, Myoung-Woon; Lee, Kwang-Ryeol; Kim, Ho-Young

    2012-11-01

    When a drop is deposited on a superhydrophilic micropillar array, the upper part of the drop (referred to as the bulk) collapses while the bottom part penetrates into the gaps of the array, forming a fringe film. Here we quantify the dynamics of this process using a combination of experiment and theory. In the early stages when the fringe extension is negligible compared to the bulk radius, both the spreading of the bulk and the entire drop footprint follow the same power law (t 1 / 4), t being time. The bulk shrinks toward the end of the spreading process due to the drainage of liquid into the fringe film. The film spreads like t 1 / 2 until the end of the process. A remarkable finding is that the entire footprint grows like t 1 / 4 despite the diffusive growth of the fringe film, implying that the shrinkage of the bulk compensates for the outward spreading of the film. We rationalize some of these results with scaling analyses based on the balance of capillary forces that drive the flow and viscous shear forces.

  6. Acetylcholine molecular arrays enable quantum information processing

    Science.gov (United States)

    Tamulis, Arvydas; Majauskaite, Kristina; Talaikis, Martynas; Zborowski, Krzysztof; Kairys, Visvaldas

    2017-09-01

    We have found self-assembly of four neurotransmitter acetylcholine (ACh) molecular complexes in a water molecules environment by using geometry optimization with DFT B97d method. These complexes organizes to regular arrays of ACh molecules possessing electronic spins, i.e. quantum information bits. These spin arrays could potentially be controlled by the application of a non-uniform external magnetic field. The proper sequence of resonant electromagnetic pulses would then drive all the spin groups into the 3-spin entangled state and proceed large scale quantum information bits.

  7. Granular gases under extreme driving

    Science.gov (United States)

    Kang, W.; Machta, J.; Ben-Naim, E.

    2010-08-01

    We study inelastic gases in two dimensions using event-driven molecular-dynamics simulations. Our focus is the nature of the stationary state attained by rare injection of large amounts of energy to balance the dissipation due to collisions. We find that under such extreme driving, with the injection rate much smaller than the collision rate, the velocity distribution has a power-law high-energy tail. The numerically measured exponent characterizing this tail is in excellent agreement with predictions of kinetic theory over a wide range of system parameters. We conclude that driving by rare but powerful energy injection leads to a well-mixed gas and constitutes an alternative mechanism for agitating granular matter. In this distinct nonequilibrium steady state, energy cascades from large to small scales. Our simulations also show that when the injection rate is comparable with the collision rate, the velocity distribution has a stretched exponential tail.

  8. Wind loads on flat plate photovoltaic array fields (nonsteady winds)

    Science.gov (United States)

    Miller, R. D.; Zimmerman, D. K.

    1981-01-01

    Techniques to predict the dynamic response and the structural dynamic loads of flat plate photovoltaic arrays due to wind turbulence were analyzed. Guidelines for use in predicting the turbulent portion of the wind loading on future similar arrays are presented. The dynamic response and the loads dynamic magnification factor of the two array configurations are similar. The magnification factors at a mid chord and outer chord location on the array illustrated and at four points on the chord are shown. The wind tunnel test experimental rms pressure coefficient on which magnification factors are based is shown. It is found that the largest response and dynamic magnification factor occur at a mid chord location on an array and near the trailing edge. A technique employing these magnification factors and the wind tunnel test rms fluctuating pressure coefficients to calculate design pressure loads due to wind turbulence is presented.

  9. An interplay between extracellular signalling and the dynamics of the exit from pluripotency drives cell fate decisions in mouse ES cells

    Directory of Open Access Journals (Sweden)

    David A. Turner

    2014-06-01

    Full Text Available Embryonic Stem cells derived from the epiblast tissue of the mammalian blastocyst retain the capability to differentiate into any adult cell type and are able to self-renew indefinitely under appropriate culture conditions. Despite the large amount of knowledge that we have accumulated to date about the regulation and control of self-renewal, efficient directed differentiation into specific tissues remains elusive. In this work, we have analysed in a systematic manner the interaction between the dynamics of loss of pluripotency and Activin/Nodal, BMP4 and Wnt signalling in fate assignment during the early stages of differentiation of mouse ES cells in culture. During the initial period of differentiation, cells exit from pluripotency and enter an Epi-like state. Following this transient stage, and under the influence of Activin/Nodal and BMP signalling, cells face a fate choice between differentiating into neuroectoderm and contributing to Primitive Streak fates. We find that Wnt signalling does not suppress neural development as previously thought and that it aids both fates in a context dependent manner. Our results suggest that as cells exit pluripotency they are endowed with a primary neuroectodermal fate and that the potency to become endomesodermal rises with time. We suggest that this situation translates into a “race for fates” in which the neuroectodermal fate has an advantage.

  10. An interplay between extracellular signalling and the dynamics of the exit from pluripotency drives cell fate decisions in mouse ES cells

    Science.gov (United States)

    Turner, David A.; Trott, Jamie; Hayward, Penelope; Rué, Pau; Martinez Arias, Alfonso

    2014-01-01

    ABSTRACT Embryonic Stem cells derived from the epiblast tissue of the mammalian blastocyst retain the capability to differentiate into any adult cell type and are able to self-renew indefinitely under appropriate culture conditions. Despite the large amount of knowledge that we have accumulated to date about the regulation and control of self-renewal, efficient directed differentiation into specific tissues remains elusive. In this work, we have analysed in a systematic manner the interaction between the dynamics of loss of pluripotency and Activin/Nodal, BMP4 and Wnt signalling in fate assignment during the early stages of differentiation of mouse ES cells in culture. During the initial period of differentiation, cells exit from pluripotency and enter an Epi-like state. Following this transient stage, and under the influence of Activin/Nodal and BMP signalling, cells face a fate choice between differentiating into neuroectoderm and contributing to Primitive Streak fates. We find that Wnt signalling does not suppress neural development as previously thought and that it aids both fates in a context dependent manner. Our results suggest that as cells exit pluripotency they are endowed with a primary neuroectodermal fate and that the potency to become endomesodermal rises with time. We suggest that this situation translates into a “race for fates” in which the neuroectodermal fate has an advantage. PMID:24950969

  11. Elevated Admission Base Deficit Is Associated with a Complex Dynamic Network of Systemic Inflammation Which Drives Clinical Trajectories in Blunt Trauma Patients

    Directory of Open Access Journals (Sweden)

    Othman Abdul-Malak

    2016-01-01

    Full Text Available We hypothesized that elevated base deficit (BD ≥ 4 mEq/L upon admission could be associated with an altered inflammatory response, which in turn may impact differential clinical trajectories. Using clinical and biobank data from 472 blunt trauma survivors, 154 patients were identified after excluding patients who received prehospital IV fluids or had alcohol intoxication. From this subcohort, 84 patients had a BD ≥ 4 mEq/L and 70 patients with BD < 4 mEq/L. Three samples within the first 24 h were obtained from all patients and then daily up to day 7 after injury. Twenty-two cytokines and chemokines were assayed using Luminex™ and were analyzed using two-way ANOVA and dynamic network analysis (DyNA. Multiple mediators of the innate and lymphoid immune responses in the BD ≥ 4 group were elevated differentially upon admission and up to 16 h after injury. DyNA revealed a higher, sustained degree of interconnectivity of the inflammatory response in the BD ≥ 4 patients during the initial 16 h after injury. These results suggest that elevated admission BD is associated with differential immune/inflammatory pathways, which subsequently could predispose patients to follow a complicated clinical course.

  12. Fiber Laser Array

    National Research Council Canada - National Science Library

    Simpson, Thomas

    2002-01-01

    ...., field-dependent, loss within the coupled laser array. During this program, Jaycor focused on the construction and use of an experimental apparatus that can be used to investigate the coherent combination of an array of fiber lasers...

  13. Universal Drive Train Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This vehicle drive train research facility is capable of evaluating helicopter and ground vehicle power transmission technologies in a system level environment. The...

  14. Control rod drives

    International Nuclear Information System (INIS)

    Kimura, Koichi.

    1994-01-01

    In control rod drives, differential pressure sensors are disposed at the inlet and the exit of a driving water pressure control valve disposed in a driving water supply device and, when deviation of fluctuation of the differential pressure from a set value is detected, a pressure control valve for driving water is controlled so as to make the differential pressure constant. The differential pressure sensors detect the differential pressure between the pressure of the control rod drives at the inlet and the exit of the driving water pressure control valve and a pressure in a reactor dome. A judging circuit judges whether the differential pressure between both sides of the driving water pressure control valve is deviated from a set value or not and, if it deviates from the set value, outputs of judging signal to the control device. In the control device, the opening degree of the driving water pressure control valve is controlled, so that the differential pressure between both sides of the driving water pressure control value is constant and does not deviate from the set value. There are provided advantageous effects of preventing abnormal control rod withdrawing phenomenon to improve safety and reliability for the control of the reactor operation. (N.H.)

  15. Medications and impaired driving.

    Science.gov (United States)

    Hetland, Amanda; Carr, David B

    2014-04-01

    To describe the association of specific medication classes with driving outcomes and provide clinical recommendations. The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on classes of medications associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests. Only English-language articles that contained findings from observational or interventional designs with ≥ 10 participants were included in this review. Cross-sectional studies, case series, and case reports were excluded. Driving is an important task and activity for the majority of adults. Some commonly prescribed medications have been associated with driving impairment measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, hypnotics, antidepressants, opioid and nonsteroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies of medication impact on sedation, sleep latency, and psychomotor function, as well as the role of alcohol, are also discussed. Psychotropic agents and those with central nervous system side effects were associated with measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific classes of medications, educate their patients, and/or consider safer alternatives.

  16. Direct Drive Hall Thruster System Development

    Science.gov (United States)

    Hoskins, W. Andrew; Homiak, Daniel; Cassady, R. Joseph; Kerslake, Tom; Peterson, Todd; Ferguson, Dale; Snyder, Dave; Mikellides, Ioannis; Jongeward, Gary; Schneider, Todd

    2003-01-01

    The sta:us of development of a Direct Drive Ha!! Thruster System is presented. 13 the first part. a s:udy of the impacts to spacecraft systems and mass benefits of a direct-drive architecture is reviewed. The study initially examines four cases of SPT-100 and BPT-4000 Hall thrusters used for north-south station keeping on an EXPRESS-like geosynchronous spacecraft and for primary propulsion for a Deep Space- 1 based science spacecraft. The study is also extended the impact of direct drive on orbit raising for higher power geosynchronous spacecraft and on other deep space missions as a function of power and delta velocity. The major system considerations for accommodating a direct drive Hall thruster are discussed, including array regulation, system grounding, distribution of power to the spacecraft bus, and interactions between current-voltage characteristics for the arrays and thrusters. The mass benefit analysis shows that, for the initial cases, up to 42 kg of dry mass savings is attributable directly to changes in the propulsion hardware. When projected mass impacts of operating the arrays and the electric power system at 300V are included, up to 63 kg is saved for the four initial cases. Adoption of high voltage lithium ion battery technology is projected to further improve these savings. Orbit raising of higher powered geosynchronous spacecraft, is the mission for which direct drive provides the most benefit, allowing higher efficiency electric orbit raising to be accomplished in a limited period of time, as well as nearly eliminating significant power processing heat rejection mass. The total increase in useful payload to orbit ranges up to 278 kg for a 25 kW spacecraft, launched from an Atlas IIA. For deep space missions, direct drive is found to be most applicable to higher power missions with delta velocities up to several km/s , typical of several Discovery-class missions. In the second part, the status of development of direct drive propulsion power

  17. Axiom turkey genotyping array

    Science.gov (United States)

    The Axiom®Turkey Genotyping Array interrogates 643,845 probesets on the array, covering 643,845 SNPs. The array development was led by Dr. Julie Long of the USDA-ARS Beltsville Agricultural Research Center under a public-private partnership with Hendrix Genetics, Aviagen, and Affymetrix. The Turk...

  18. What Drives Politicians’ Online Popularity?

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis; Vaccari, Cristian

    2013-01-01

    The number of website visits, Facebook friends, or Twitter followers that politicians attract varies greatly, but little is known about what drives politicians' online popularity. In this article, we use data from a systematic tracking of congressional candidates' popularity on four web platforms......-seat races tend to attract larger audiences online, as do candidates who are more visible on political blogs. Surprisingly, how intensely candidates are covered in news media, how popular they are in opinion polls, and how much money they spend during the campaign show no significant effect. These findings...... help us understand the dynamics of internet politics, and have wider implications for candidate competition and party politics....

  19. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  20. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  1. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV......How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV...

  2. Piezoelectric drive circuit

    Science.gov (United States)

    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.

  3. Switched reluctance motor drives

    Indian Academy of Sciences (India)

    Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

  4. Self-driving carsickness.

    NARCIS (Netherlands)

    Diels, C.; Bos, J.E.

    2016-01-01

    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

  5. Self-driving carsickness

    NARCIS (Netherlands)

    Diels, C.; Bos, J.E.

    2016-01-01

    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

  6. Control rod drives

    International Nuclear Information System (INIS)

    Nakamura, Akira.

    1984-01-01

    Purpose: To enable to monitor the coupling state between a control rod and a control rod drive. Constitution: After the completion of a control rod withdrawal, a coolant pressure is applied to a control rod drive being adjusted so as to raise only the control rod drive and, in a case where the coupling between the control rod drive and the control rod is detached, the former is elevated till it contacts the control rod and then stopped. The actual stopping position is detected by an actual position detection circuit and compared with a predetermined position stored in a predetermined position detection circuit. If both of the positions are not aligned with each other, it is judged by a judging circuit that the control rod and the control rod drives are not combined. (Sekiya, K.)

  7. The Red Lake Peatland Observatory (RLPO): A multi-sensor instrument array for monitoring carbon-water dynamics in a large northern peatland

    Science.gov (United States)

    Glaser, P. H.; Rosenberry, D. O.; Reeve, A. S.; Siegel, D. I.; Chanton, J. P.; Slater, L. D.; Comas, X.; Rhoades, J. M.; Allen, L.; Corbett, J.; D'Andrilli, J.; Tfilany, M. I.; Parsekian, A.; Nolan, J.; Sarkar, M.; Gracz, M.; Morin, P. J.

    2009-12-01

    The 1200 sq km Red Lake peatland in northern Minnesota has been the focus of an ongoing study of carbon-groundwater interactions for over 30 years. This large continuous expanse of peatland contains several major bog complexes, each of which covers over 100 sq. km. Each bog complex has 1) a forested bog crest that grades downslope into 2) gently sloping Sphagnum lawns and 3) fen water tracks that divide the lower flanks of the bog into ovoid-shaped "islands." Building upon past work we installed 20 new instrument stations in the RLII watershed to monitor fluxes of carbon, water, and heat continuously within the 4m-thick peat profile and also the atmospheric boundary layer on scales of meters to kilometers. This integrated array of stations comprise the Red Lake Peatland Observatory (RLPO), which now collects data from a) 14 dual-frequency GPS units arranged in a nested triangular network measuring vertical and lateral deformations of the peat mass caused by changes in water and gas storage, b) 2 eddy covariance units that monitor fluxes in heat, momentum, carbon dioxide, and water vapor across the atmospheric boundary layer, and c) 4 stations equipped with instrumented piezometers and meteorological sensors for measuring changes in water and gas storage within the entire peat profile. All remote stations communicate by radio to a base station and through the internet to a centralized database at the University of Minnesota that automatically downloads and stores sensor data on a daily basis. Large degassing events were previously detected by monitoring sharp depressuring cycles from a zone of overpressure at 2 m below the bog crest site that occurred synchronously with vertical oscillations of the peat surface in excess of 10 cm in hours. These types of measurements have now been extended to much finer sampling intervals across a much broader portion of the peatland. Free--phase gas appears to accumulate throughout the peat profile in winter after the surface

  8. Power Curves in a Wind Turbine Array: A Numerical Study

    DEFF Research Database (Denmark)

    Meyer Forsting, Alexander Raul

    The impact of measuring a power curve inside a wind turbine array is investigated using computational fluid dynamics. The array consists of five aligned rotors that yaw with the free-stream wind direction. The flow-field in front of a wind turbine array changes with wind direction and hence...... the individual power output of each turbine. By incorporating the current IEC standards on power performance measurements, the bias in the power performance of turbines in an array over an isolated rotor is determined. The power change depends on the position of the turbine in the array and reaches maximally 9...

  9. A large-signal model for CMUT arrays with arbitrary membrane geometry operating in non-collapsed mode.

    Science.gov (United States)

    Satir, Sarp; Zahorian, Jaime; Degertekin, F Levent

    2013-11-01

    A large-signal, transient model has been developed to predict the output characteristics of a CMUT array operated in the non-collapse mode. The model is based on separation of the nonlinear electrostatic voltage-to-force relation and the linear acoustic array response. For modeling of linear acoustic radiation and crosstalk effects, the boundary element method is used. The stiffness matrix in the vibroacoustics calculations is obtained using static finite element analysis of a single membrane which can have arbitrary geometry and boundary conditions. A lumped modeling approach is used to reduce the order of the system for modeling the transient nonlinear electrostatic actuation. To accurately capture the dynamics of the non-uniform electrostatic force distribution over the CMUT electrode during large deflections, the membrane electrode is divided into patches shaped to match higher order membrane modes, each introducing a variable to the system model. This reduced order nonlinear lumped model is solved in the time domain using commercial software. The model has two linear blocks to calculate the displacement profile of the electrode patches and the output pressure for a given force distribution over the array. The force-to-array-displacement block uses the linear acoustic model, and the Rayleigh integral is evaluated to calculate the pressure at any field point. Using the model, the time-domain transmitted pressure can be simulated for different large drive signal configurations. The acoustic model is verified by comparison to harmonic FEA in vacuum and fluid for high- and low-aspect-ratio membranes as well as mass-loaded membranes. The overall software model is verified by comparison to transient 3-D finite element analysis and experimental results for different large drive signals, and an example for a phased array simulation is given.

  10. A Large Signal Model for CMUT Arrays with Arbitrary Membrane Geometries Operating in Non-Collapsed Mode

    Science.gov (United States)

    Satir, Sarp; Zahorian, Jaime; Degertekin, F. Levent

    2014-01-01

    A large signal, transient model has been developed to predict the output characteristics of a CMUT array operated in the non-collapse mode. The model is based on separation of the nonlinear electrostatic voltage-to-force relation and the linear acoustic array response. For linear acoustic radiation and crosstalk effects, the boundary element method is used. The stiffness matrix in the vibroacoustics calculations is obtained using static finite element analysis of a single membrane which can have arbitrary geometry and boundary conditions. A lumped modeling approach is used to reduce the order of the system for modeling the transient nonlinear electrostatic actuation. To accurately capture the dynamics of the non-uniform electrostatic force distribution over the CMUT electrode during large deflections, the membrane electrode is divided into patches shaped to match higher order membrane modes, each introducing a variable to the system model. This reduced order nonlinear lumped model is solved in the time domain using Simulink. The model has two linear blocks to calculate the displacement profile of the electrode patches and the output pressure for a given force distribution over the array, respectively. The force to array displacement block uses the linear acoustic model, and the Rayleigh integral is evaluated to calculate the pressure at any field point. Using the model, the transient transmitted pressure can be simulated for different large signal drive signal configurations. The acoustic model is verified by comparison to harmonic FEA in vacuum and fluid for high and low aspect ratio membranes as well as mass-loaded membranes. The overall Simulink model is verified by comparison to transient 3D FEA and experimental results for different large drive signals; and an example for a phased array simulation is given. PMID:24158297

  11. DC switching regulated power supply for driving an inductive load

    Science.gov (United States)

    Dyer, George R.

    1986-01-01

    A power supply for driving an inductive load current from a dc power supply hrough a regulator circuit including a bridge arrangement of diodes and switching transistors controlled by a servo controller which regulates switching in response to the load current to maintain a selected load current. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. The regulator may be operated in three "stages" or modes: (1) For current runup in the load, both first and second transistor switch arrays are turned "on" and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned "off", and load current "flywheels" through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays "off", allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load. The three operating states are controlled automatically by the controller.

  12. Dynamic hohlraum and ICF pellet implosion experiments on Z

    International Nuclear Information System (INIS)

    Nash, T.J.; Derzon, M.S.; Chandler, G.A.

    1999-01-01

    By stabilizing an imploding z-pinch on Z (20 MA, 100 ns) with a solid current return can and a nested wire array the authors have achieved dynamic hohlraum radiation temperatures over 200 eV at a diameter of approximately 1 mm. The pinch configuration yielding this temperature is a nested tungsten wire array of 240 and 120 wires at 4 and 2 cm diameters weighing 2 and 1 mg, 1 cm long, imploding onto a 5 mm diameter, 14 mg/cc cylindrical CH foam, weighing 3 mg. They have used a single 4 cm diameter tungsten wire array to drive a 1.6 mm diameter ICF capsule mounted in a 6 mg/cc foam inside a 3 mg copper annulus at 5 mm diameter, and measured x-ray emissions indicative of the pellet implosion. Mounting the pellet in foam may have caused the hohlraum to become equator-hot. They will present results from upcoming pellet experiments in which the pellet is mounted by thread and driven by a larger diameter, 6 or 7 mm, copper annulus to improve radiation drive symmetry. They will also discuss designs for tapered foam annular targets that distort a cylindrical pinch into a quasi-sphere that will wrap around an ICF pellet to further improve drive symmetry

  13. Design of driving control strategy of torque distribution for two - wheel independent drive electric vehicle

    Science.gov (United States)

    Zhang, Chuanwei; Zhang, Dongsheng; Wen, Jianping

    2018-02-01

    In order to coordinately control the torque distribution of existing two-wheel independent drive electric vehicle, and improve the energy efficiency and control stability of the whole vehicle, the control strategies based on fuzzy control were designed which adopt the direct yaw moment control as the main line. For realizing the torque coordination simulation of the two-wheel independent drive vehicle, the vehicle model, motor model and tire model were built, including the vehicle 7 - DOF dynamics model, motion equation, torque equation. Finally, in the Carsim - Simulink joint simulation platform, the feasibility of the drive control strategy was verified.

  14. Turbulent current drive mechanisms

    Science.gov (United States)

    McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

    2017-08-01

    Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm's law and hence provide an ideal means for driving deviations from neoclassical predictions.

  15. Identifying Method of Drunk Driving Based on Driving Behavior

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhao

    2011-05-01

    Full Text Available Drunk driving is one of the leading causes contributing to traffic crashes. There are numerous issues that need to be resolved with the current method of identifying drunk driving. Driving behavior, with the characteristic of real-time, was extensively researched to identify impaired driving behaviors. In this paper, the drives with BACs above 0.05% were defined as drunk driving state. A detailed comparison was made between normal driving and drunk driving. The experiment in driving simulator was designed to collect the driving performance data of the groups. According to the characteristics analysis for the effect of alcohol on driving performance, seven significant indicators were extracted and the drunk driving was identified by the Fisher Discriminant Method. The discriminant function demonstrated a high accuracy of classification. The optimal critical score to differentiate normal from drinking state was found to be 0. The evaluation result verifies the accuracy of classification method.

  16. Force sensitive carbon nanotube arrays for biologically inspired airflow sensing

    Science.gov (United States)

    Maschmann, Matthew R.; Dickinson, Ben; Ehlert, Gregory J.; Baur, Jeffery W.

    2012-09-01

    The compressive electromechanical response of aligned carbon nanotube (CNT) arrays is evaluated for use as an artificial hair sensor (AHS) transduction element. CNT arrays with heights of 12, 75, and 225 µm are examined. The quasi-static and dynamic sensitivity to force, response time, and signal drift are examined within the range of applied stresses predicted by a mechanical model applicable to the conceptual CNT array-based AHS (0-1 kPa). Each array is highly sensitive to compressive loading, with a maximum observed gauge factor of 114. The arrays demonstrate a repeatable response to dynamic cycling after a break-in period of approximately 50 cycles. Utilizing a four-wire measurement electrode configuration, the change in contact resistance between the array and the electrodes is observed to dominate the electromechanical response of the arrays. The response time of the CNT arrays is of the order of 10 ms. When the arrays are subjected to constant stress, mechanical creep is observed that results in a signal drift that generally diminishes the responsiveness of the arrays, particularly at stress approaching 1 kPa. The results of this study serve as a preliminary proof of concept for utilizing CNT arrays as a transduction mechanism for a proposed artificial hair sensor. Such a low profile and light-weight flow sensor is expected to have application in a number of applications including navigation and state awareness of small air vehicles, similar in function to natural hair cell receptors utilized by insects and bats.

  17. The Colorado Lightning Mapping Array

    Science.gov (United States)

    Rison, W.; Krehbiel, P. R.; Thomas, R. J.; Rodeheffer, D.; Fuchs, B.

    2012-12-01

    A fifteen station Lightning Mapping Array (LMA) was installed in northern Colorado in the spring of 2012. While the driving force for the array was to produce 3-dimensional lightning data to support the Deep Convective Clouds and Chemistry (DC3) Experiment (Barth, this conference), data from the array are being used for several other projects. These include: electrification studies in conjunction with the CSU CHILL radar (Lang et al, this conference); observations of the parent lightning discharges of sprites (Lyons et al, this conference); trying to detect upward discharges triggered by wind turbines, characterizing conditions in which aircraft flying through clouds produce discharges which can be detected by the LMA, and other opportunities, such as observations of lightning in pyrocumulus clouds produced by the High Park Fire west of Fort Collins, CO. All the COLMA stations are solar-powered, and use broadband cellular modems for data communications. This makes the stations completely self-contained and autonomous, allowing a station to be installed anywhere a cellular signal is available. Because most of the stations were installed well away from anthropogenic noise sources, the COLMA is very sensitive. This is evidenced by the numerous plane tracks detected in its the vicinity. The diameter, D, of the COLMA is about 100 km, significantly larger than other LMAs. Because the error in the radial distance r is proportional to (r/D)2, and the error in the altitude z is proportional to (z/D)2, the larger array diameter greatly expands the usable range of the COLMA. The COLMA is able to detect and characterize lighting flashes to a distance of about 350 km from the array center. In addition to a web-based display (lightning.nmt.edu/colma), geo-referenced images are produced and updated at one-minute intervals. These geo-referenced images can be used to overlay the real-time lightning data on Google Earth and other mapping software. These displays were used by the DC3

  18. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  19. Linear step drive

    International Nuclear Information System (INIS)

    Haniger, L.; Elger, R.; Kocandrle, L.; Zdebor, J.

    1986-01-01

    A linear step drive is described developed in Czechoslovak-Soviet cooperation and intended for driving WWER-1000 control rods. The functional principle is explained of the motor and the mechanical and electrical parts of the drive, power control, and the indicator of position are described. The motor has latches situated in the reactor at a distance of 3 m from magnetic armatures, it has a low structural height above the reactor cover, which suggests its suitability for seismic localities. Its magnetic circuits use counterpoles; the mechanical shocks at the completion of each step are damped using special design features. The position indicator is of a special design and evaluates motor position within ±1% of total travel. A drive diagram and the flow chart of both the control electronics and the position indicator are presented. (author) 4 figs

  20. Drugs and driving

    NARCIS (Netherlands)

    Walsh, J. Michael; De Gier, Johan J.; Christopherson, Asbjørg S.; Verstraete, Alain G.

    The authors present a global overview on the issue of drugs and driving covering four major areas: (1) Epidemiology and Prevalence-which reviews epidemiological research, summarizes available information, discusses the methodological shortcomings of extant studies, and makes recommendations for

  1. Science of driving.

    Science.gov (United States)

    2016-08-01

    The Science of Driving project focused on developing a collaborative relationship to develop curriculum units for middle school and high school students to engage them in exciting real-world scenarios. This effort involved faculty, staff, and student...

  2. Phased-array radars

    Science.gov (United States)

    Brookner, E.

    1985-02-01

    The operating principles, technology, and applications of phased-array radars are reviewed and illustrated with diagrams and photographs. Consideration is given to the antenna elements, circuitry for time delays, phase shifters, pulse coding and compression, and hybrid radars combining phased arrays with lenses to alter the beam characteristics. The capabilities and typical hardware of phased arrays are shown using the US military systems COBRA DANE and PAVE PAWS as examples.

  3. CONTROL ROD DRIVE

    Science.gov (United States)

    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.

  4. Instant Google Drive starter

    CERN Document Server

    Procopio, Mike

    2013-01-01

    This book is a Starter which teaches you how to use Google Drive practically. This book is perfect for people of all skill levels who want to enjoy the benefits of using Google Drive to safely store their files online and in the cloud. It's also great for anyone looking to learn more about cloud computing in general. Readers are expected to have an Internet connection and basic knowledge of using the internet.

  5. Belt drive construction improvement

    Directory of Open Access Journals (Sweden)

    I.Yu. Khomenko

    2012-08-01

    Full Text Available The possibility of the traction capacity increase of the belt drive TRK is examined. This was done for the purpose of air conditioning system of passenger car with double-generator system energy supplying. Belts XPC (made by the German firm «Continental ContiTech» testing were conducted. The results confirmed the possibility of their usage in order to improve belt drive TRK characteristics.

  6. Mathematical model of failure the drives suspensions of the conveyor with suspended belt and distributed drive at jamming rollers

    Directory of Open Access Journals (Sweden)

    Tolkachev E.N.

    2017-09-01

    Full Text Available The article is devoted to the topical issue, which is related to simulation of the failures of drives suspensions of the conveyor with suspended belt and distributed drive. A mathematical model of the failure of individual drives of suspensions due to the jamming of the rollers has been developed. Dynamic characteristics of the basic version of a conveyor with suspended belt were simulated.

  7. Epilepsy and driving

    Directory of Open Access Journals (Sweden)

    Moetamedi M

    2000-09-01

    Full Text Available Epilepsy is a disease with high prevalence, which interferes driving and may lead to car accident; This case-control study has been done on 100 epileptic patients and 100 persons as control group, who had history of driving. We gathered our patients with face to face interview and registering their information in special forms which were prepared for this study. There were three times more accidents among epileptic cases comparing with control group and this difference was more considerable in men and in patients under 35 years old. The cause of accident were not seizure attack in more than 60% of the patients and these ordinary accidents were also more in case group. Epileptic patients with history of car accidents during driving had poor drug compliance comparing with the epileptics without history of an accident so drug compliance may be valuable in predicting accident in these patients. We have also found poor drug compliance in whom seizure attacks caused accident for them. 58% of the epileptics had not consulted their physician about driving. 43.3% of seizures during driving were of generalized type and none of the patients had inform police about their disease during getting driving license.

  8. Dementia and driving.

    Science.gov (United States)

    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.

  9. Self-driving carsickness.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  10. Integrated avalanche photodiode arrays

    Science.gov (United States)

    Harmon, Eric S.

    2015-07-07

    The present disclosure includes devices for detecting photons, including avalanche photon detectors, arrays of such detectors, and circuits including such arrays. In some aspects, the detectors and arrays include a virtual beveled edge mesa structure surrounded by resistive material damaged by ion implantation and having side wall profiles that taper inwardly towards the top of the mesa structures, or towards the direction from which the ion implantation occurred. Other aspects are directed to masking and multiple implantation and/or annealing steps. Furthermore, methods for fabricating and using such devices, circuits and arrays are disclosed.

  11. Cover array string reconstruction

    OpenAIRE

    Crochemore, Maxime; S. Iliopoulos, Costas; P. Pissis, Solon; Tischler, German

    2010-01-01

    International audience; A proper factor u of a string y is a cover of y if every letter of y is within some occurrence of u in y. The concept generalises the notion of periods of a string. An integer array C is the minimal-cover (resp. maximal-cover) array of y if C[i] is the minimal (resp. maximal) length of covers of y[0.. i], or zero if no cover exists. In this paper, we present a constructive algorithm checking the validity of an array as a minimal-cover or maximal-cover array of some str...

  12. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water reflected (i.e., surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established. When evaluating arrays, it has become more common for analysts to use calculations to demonstrate the safety of the array configuration. In performing these calculations, the analyst has considerable freedom concerning the assumptions made for modeling the reflection of the array. Considerations are given for the physical layout of the array with little or no discussion (or demonstration) of what conditions are bounded by the assumed reflection conditions. For example, an array may be generically evaluated by placing it in a corner of a room in which the opposing walls are far away. Typically, it is believed that complete flooding of the room is incredible, so the array is evaluated for various levels of water mist interspersed among array containers. This paper discusses some assumptions that are made regarding storage array reflection

  13. Transition edge sensor series array bolometer

    International Nuclear Information System (INIS)

    Beyer, J

    2010-01-01

    A transition edge sensor series array (TES-SA) is an array of identical TESs that are connected in series by low-inductance superconducting wiring. The array elements are equally and well thermally coupled to the absorber and respond to changes in the absorber temperature in synchronization. The TES-SA total resistance increases compared to a single TES while the shape of the superconducting transition is preserved. We are developing a TES-SA with a large number, hundreds to thousands, of array elements with the goal of enabling the readout of a TES-based bolometer operated at 4.2 K with a semiconductor-based amplifier located at room temperature. The noise and dynamic performance of a TES-SA bolometer based on a niobium/aluminum bilayer is analyzed. It is shown that stable readout of the bolometer with a low-noise transimpedance amplifier is feasible.

  14. Traveling-wave antenna for fast-wave heating and current drive in tokamaks

    International Nuclear Information System (INIS)

    Ikezi, H.; Phelps, D.A.

    1997-01-01

    The travelling-wave antenna for heating and current drive in the ion cyclotron range of frequencies is shown theoretically to have loading and wavenumber spectra that are largely independent of plasma conditions. These characteristics have been demonstrated in low-power experiments on the DIII-D tokamak, in which a standard four-strap antenna was converted to a traveling-wave antenna through use of external coupling elements. The experiments indicate that the array maintains good impedance matching without dynamic tuning during abrupt changes in the plasma, such as during L- to H-mode transitions, edge-localized mode activity, and disruptions. An analytic model was developed that exhibits the features observed in the experiments. Guidelines for the design of travelling-wave antennas are derived from the validated model. 11 refs., 14 figs

  15. Traveling wave antenna for fast wave heating and current drive in tokamaks

    International Nuclear Information System (INIS)

    Ikezi, H.; Phelps, D.A.

    1995-07-01

    The traveling wave antenna for heating and current drive in the ion cyclotron range of frequencies is shown theoretically to have loading and wavenumber spectrum which are largely independent of plasma conditions. These characteristics have been demonstrated in low power experiments on the DIII-D tokamak, in which a standard four-strap antenna was converted to a traveling wave antenna through use of external coupling elements. The experiments indicate that the array maintains good impedance matching without dynamic tuning during abrupt changes in the plasma, such as during L- to H-mode transitions, edge localized mode activity, and disruptions. An analytic model was developed which exhibits the features observed in the experiments. Guidelines for the design of traveling wave antennas are derived from the validated model

  16. Solar array stepping to minimize array excitation

    Science.gov (United States)

    Bhat, Mahabaleshwar K. P. (Inventor); Liu, Tung Y. (Inventor); Plescia, Carl T. (Inventor)

    1989-01-01

    Mechanical oscillations of a mechanism containing a stepper motor, such as a solar-array powered spacecraft, are reduced and minimized by the execution of step movements in pairs of steps, the period between steps being equal to one-half of the period of torsional oscillation of the mechanism. Each pair of steps is repeated at needed intervals to maintain desired continuous movement of the portion of elements to be moved, such as the solar array of a spacecraft. In order to account for uncertainty as well as slow change in the period of torsional oscillation, a command unit may be provided for varying the interval between steps in a pair.

  17. Advanced Composite Truss (ACT) Printing for Large Solar Array Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Large solar arrays (100 kW-1 MW) are required in order to generate the power necessary for solar electric propulsion to drive NASA's future missions, including:...

  18. Lead chalcogenides based IR photosensitive array detectors with coordinate addressing

    Science.gov (United States)

    Agranov, G. A.; Novoselov, S. K.; Stepanov, R. M.; Doon, A. Z.; Pashkevich, A. V.; Ivanov, A. I.; Nemchuk, I. K.; Nesterov, V. K.; Skoriukin, V. E.

    1992-12-01

    Coordinate addressed photodetector arrays based on thin films of lead chalcogenides and operating in different wavebands of the infrared spectral regions are described. The arrays feature high sensitivity, close to BLIP mode, wide dynamic range, and low heat dissipation. Their advantages include random access, element block selection, image scaling, and on chip data encoding. Different design configurations with elements from 128 by 128 to 512 by 512 are discussed and experimental parameters and characteristics of the experimental arrays are presented.

  19. Focal plane array with modular pixel array components for scalability

    Science.gov (United States)

    Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

    2014-12-09

    A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

  20. Pattern formation in arrays of chemical oscillators

    Indian Academy of Sciences (India)

    ... natural systems the mass of the chemical species is transmitted from one site to another with finite velocity, which makes delay coupling appropriate in this system. When all the assumptions mentioned above are taken into account, the dynamics of an array comprising of N droplets is given by 2N differential equations:.

  1. Micromirror array for protein micro array fabrication

    Science.gov (United States)

    Lee, Kook-Nyung; Shin, Dong-Sik; Lee, Yoon-Sik; Kim, Yong-Kweon

    2003-05-01

    We have designed, fabricated and characterized a micromirror array for protein microarray fabrication that has a simple structure, and the straightforward fabrication process for the mirror will allow the use of low-cost mirrors in protein pattern applications. The characteristics of an exposure system utilizing the micromirror array have been demonstrated by means of an experiment employing a photoresist that is in general use in the semiconductor industry. The micromirror dimensions were 54 × 54 mum2, with a 30 mum separation between mirrors, and a 5.5 mum gap from the bottom electrode so that the mirror had an approximately 10° deflection angle. The size and separation of the mirror were designed in consideration of the protein pattern size and pitch, in contrast with the commercial Texas Instruments Digital Light Processor, which is utilized in the components of projection display systems. The exposure system combined with the micromirror has been used in the photochemical synthesis of chemical ligands via protein immobilization on a chip. Several photosynthesis experiments for peptide array synthesis have been carried out using the micromirror array. Parallel experiments on photochemical ligand synthesis on a chip can easily be performed in the laboratory using this exposure system.

  2. Triggering the GRANDE array

    International Nuclear Information System (INIS)

    Wilson, C.L.; Bratton, C.B.; Gurr, J.; Kropp, W.; Nelson, M.; Sobel, H.; Svoboda, R.; Yodh, G.; Burnett, T.; Chaloupka, V.; Wilkes, R.J.; Cherry, M.; Ellison, S.B.; Guzik, T.G.; Wefel, J.; Gaidos, J.; Loeffler, F.; Sembroski, G.; Goodman, J.; Haines, T.J.; Kielczewska, D.; Lane, C.; Steinberg, R.; Lieber, M.; Nagle, D.; Potter, M.; Tripp, R.

    1990-01-01

    A brief description of the Gamma Ray And Neutrino Detector Experiment (GRANDE) is presented. The detector elements and electronics are described. The trigger logic for the array is then examined. The triggers for the Gamma Ray and the Neutrino portions of the array are treated separately. (orig.)

  3. Large-scale nanophotonic phased array.

    Science.gov (United States)

    Sun, Jie; Timurdogan, Erman; Yaacobi, Ami; Hosseini, Ehsan Shah; Watts, Michael R

    2013-01-10

    Electromagnetic phased arrays at radio frequencies are well known and have enabled applications ranging from communications to radar, broadcasting and astronomy. The ability to generate arbitrary radiation patterns with large-scale phased arrays has long been pursued. Although it is extremely expensive and cumbersome to deploy large-scale radiofrequency phased arrays, optical phased arrays have a unique advantage in that the much shorter optical wavelength holds promise for large-scale integration. However, the short optical wavelength also imposes stringent requirements on fabrication. As a consequence, although optical phased arrays have been studied with various platforms and recently with chip-scale nanophotonics, all of the demonstrations so far are restricted to one-dimensional or small-scale two-dimensional arrays. Here we report the demonstration of a large-scale two-dimensional nanophotonic phased array (NPA), in which 64 × 64 (4,096) optical nanoantennas are densely integrated on a silicon chip within a footprint of 576 μm × 576 μm with all of the nanoantennas precisely balanced in power and aligned in phase to generate a designed, sophisticated radiation pattern in the far field. We also show that active phase tunability can be realized in the proposed NPA by demonstrating dynamic beam steering and shaping with an 8 × 8 array. This work demonstrates that a robust design, together with state-of-the-art complementary metal-oxide-semiconductor technology, allows large-scale NPAs to be implemented on compact and inexpensive nanophotonic chips. In turn, this enables arbitrary radiation pattern generation using NPAs and therefore extends the functionalities of phased arrays beyond conventional beam focusing and steering, opening up possibilities for large-scale deployment in applications such as communication, laser detection and ranging, three-dimensional holography and biomedical sciences, to name just a few.

  4. Control rod drives

    International Nuclear Information System (INIS)

    Hayakawa, Hiroyasu.

    1979-01-01

    Purpose: To enable rapid control in a simple circuit by providing a motor control device having an electric capacity capable of simultaneously driving all of the control rods rapidly only in the inserting direction as well as a motor controlling device capable of fine control for the insertion and extraction at usual operation. Constitution: The control rod drives comprise a first motor control device capable of finely controlling the control rods both in inserting and extracting directions, a second motor control device capable of rapidly driving the control rods only in the inserting direction, and a first motor switching circuit and a second motor switching circuit switched by switches. Upon issue of a rapid insertion instruction for the control rods, the second motor switching circuit is closed by the switch and the second motor control circuit and driving motors are connected. Thus, each of the control rod driving motors is driven at a high speed in the inserting direction to rapidly insert all of the control rods. (Yoshino, Y.)

  5. Micromachined electrode array

    Science.gov (United States)

    Okandan, Murat; Wessendorf, Kurt O.

    2007-12-11

    An electrode array is disclosed which has applications for neural stimulation and sensing. The electrode array, in certain embodiments, can include a plurality of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. In other embodiments of the electrode array, the electrodes can be fixed to the substrate. The electrode array can be formed from a combination of bulk and surface micromachining, and can include electrode tips having an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis.

  6. Soft X-ray radiation parameters of nested tungsten wire array

    International Nuclear Information System (INIS)

    Ning Jiamin; Jiang Shilun; Xu Rongkun; Xu Zeping; Li Zhenghong; Yang Jianlun

    2011-01-01

    Implosions with nested tungsten wire array were performed at the Angara-5-1 facility in Russian Research Centre. The experimental results of nested tungsten wire array are compared with those of single array. Radiation parameters of nested array are discussed based on four different dynamic models. When the implosions of outer and inner wire arrays are synchronized,the relatively uniform distribution of inner layer plasma will improve the uniformity of outer layer plasma. As compared with single array, nested array has an increase of 32% in X-ray radiation power. (authors)

  7. Planar electron beams in a wiggler magnet array

    Indian Academy of Sciences (India)

    2013-02-01

    Feb 1, 2013 ... magnet array. The calculation includes self-consistent effects of beam-generated fields. Our results ... width. The feasibility calculation addresses to a system expected to drive for 13–20 GHz BWO with rippled waveguide ... designed by Read et al. Owing to the relatively low voltage, self-magnetic fields were.

  8. Position sensor for linear synchronous motors employing halbach arrays

    Science.gov (United States)

    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.

  9. Gears and gear drives

    CERN Document Server

    Jelaska, Damir T

    2012-01-01

    Understanding how gears are formed and how they interact or 'mesh' with each other is essential when designing equipment that uses gears or gear trains. The way in which gear teeth are formed and how they mesh is determined by their geometry and kinematics, which is the topic of this book.  Gears and Gear Drives provides the reader with comprehensive coverage of gears and gear drives. Spur, helical, bevel, worm and planetary gears are all covered, with consideration given to their classification, geometry, kinematics, accuracy control, load capacity and manufacturing. Cylindric

  10. Blow molding electric drives of Mechanical Engineering

    Science.gov (United States)

    Bukhanov, S. S.; Ramazanov, M. A.; Tsirkunenko, A. T.

    2018-03-01

    The article considers the questions about the analysis of new possibilities, which gives the use of adjustable electric drives for blowing mechanisms of plastic production. Thus, the use of new semiconductor converters makes it possible not only to compensate the instability of the supply network by using special dynamic voltage regulators, but to improve (correct) the power factor. The calculation of economic efficiency in controlled electric drives of blowing mechanisms is given. On the basis of statistical analysis, the calculation of the reliability parameters of the regulated electric drives’ elements under consideration is given. It is shown that an increase in the reliability of adjustable electric drives is possible both due to overestimation of the electric drive’s installed power, and in simpler schemes with pulse-vector control.

  11. Sensor array signal processing

    CERN Document Server

    Naidu, Prabhakar S

    2009-01-01

    Chapter One: An Overview of Wavefields 1.1 Types of Wavefields and the Governing Equations 1.2 Wavefield in open space 1.3 Wavefield in bounded space 1.4 Stochastic wavefield 1.5 Multipath propagation 1.6 Propagation through random medium 1.7 ExercisesChapter Two: Sensor Array Systems 2.1 Uniform linear array (ULA) 2.2 Planar array 2.3 Distributed sensor array 2.4 Broadband sensor array 2.5 Source and sensor arrays 2.6 Multi-component sensor array2.7 ExercisesChapter Three: Frequency Wavenumber Processing 3.1 Digital filters in the w-k domain 3.2 Mapping of 1D into 2D filters 3.3 Multichannel Wiener filters 3.4 Wiener filters for ULA and UCA 3.5 Predictive noise cancellation 3.6 Exercises Chapter Four: Source Localization: Frequency Wavenumber Spectrum4.1 Frequency wavenumber spectrum 4.2 Beamformation 4.3 Capon's w-k spectrum 4.4 Maximum entropy w-k spectrum 4.5 Doppler-Azimuth Processing4.6 ExercisesChapter Five: Source Localization: Subspace Methods 5.1 Subspace methods (Narrowband) 5.2 Subspace methods (B...

  12. Coulomb coupling and the role of symmetries in quantum-dot arrays for cellular automata

    International Nuclear Information System (INIS)

    Ramirez, F.; Cota, E.; Ulloa, S. E.

    2000-01-01

    Using a group-theoretical analysis of the symmetries of a quantum dot array, we investigate the role of defects on the energetics of the system and the resulting charge configurations (or polarization of the cell). We find that for the typical four- or five-element geometries proposed, even small asymmetries introduced by defects in the system, or variations in the local electrostatic environment, can give rise to large effects on the polarization of the ground state and the corresponding low-energy excitations. These shifts are likely to produce important effects in the operation of the cellular automata proposed using these quantum dots. In particular, we find that the sensitivity to polarization changes induced by a driver cell decreases dramatically, and the polarization values are no longer fully defined. These effects would both force the use of stronger driving fields, and may also complicate the dynamical behavior of the cellular automata. (c) 2000 The American Physical Society

  13. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

  14. Introduction to adaptive arrays

    CERN Document Server

    Monzingo, Bob; Haupt, Randy

    2011-01-01

    This second edition is an extensive modernization of the bestselling introduction to the subject of adaptive array sensor systems. With the number of applications of adaptive array sensor systems growing each year, this look at the principles and fundamental techniques that are critical to these systems is more important than ever before. Introduction to Adaptive Arrays, 2nd Edition is organized as a tutorial, taking the reader by the hand and leading them through the maze of jargon that often surrounds this highly technical subject. It is easy to read and easy to follow as fundamental concept

  15. Comparing Expert and Novice Driving Behavior in a Driving Simulator

    Directory of Open Access Journals (Sweden)

    Hiran B. Ekanayake

    2014-02-01

    Full Text Available This paper presents a study focused on comparing driving behavior of expert and novice drivers in a mid-range driving simulator with the intention of evaluating the validity of driving simulators for driver training. For the investigation, measurements of performance, psychophysiological measurements, and self-reported user experience under different conditions of driving tracks and driving sessions were analyzed. We calculated correlations between quantitative and qualitative measures to enhance the reliability of the findings. The experiment was conducted involving 14 experienced drivers and 17 novice drivers. The results indicate that driving behaviors of expert and novice drivers differ from each other in several ways but it heavily depends on the characteristics of the task. Moreover, our belief is that the analytical framework proposed in this paper can be used as a tool for selecting appropriate driving tasks as well as for evaluating driving performance in driving simulators.

  16. Simulation and Analysis of Roller Chain Drive Systems

    DEFF Research Database (Denmark)

    Pedersen, Sine Leergaard

    The subject of this thesis is simulation and analysis of large roller chain drive systems, such as e.g. used in marine diesel engines. The aim of developing a chain drive simulation program is to analyse dynamic phenomena of chain drive systems and investigate different design changes...... to the systems, in order to remove unwanted phenomena. Such a computer program can, when properly validated, be used as an alternative to or in combination with physical experiments. Prior investigations in this area have been done with a focus on smaller chains in high speed chain drives. For large low speed...... systems other phenomena occur and therefore, a specific model of the marine engine chain drive is of interest. The research objective of the work presented in this thesis is to contribute with a novel theoretical basis for the analysis of chain drive systems, by posing and validating different...

  17. Gaze-controlled Driving

    DEFF Research Database (Denmark)

    Tall, Martin; Alapetite, Alexandre; San Agustin, Javier

    2009-01-01

    We investigate if the gaze (point of regard) can control a remote vehicle driving on a racing track. Five different input devices (on-screen buttons, mouse-pointing low-cost webcam eye tracker and two commercial eye tracking systems) provide heading and speed control on the scene view transmitted...

  18. Drive-Through Training

    Science.gov (United States)

    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…

  19. Driving While Intoxicated.

    Science.gov (United States)

    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…

  20. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-01

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  1. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Septon, Kendall K [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-11

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  2. Overview of Nanoparticle Array Formation by Wet Coating

    International Nuclear Information System (INIS)

    Maenosono, Shinya; Okubo, Tatsuya; Yamaguchi, Yukio

    2003-01-01

    We give a concise overview of nanoparticle array formation by wet coating techniques including patterned assembly, surface modification of nanoparticles, rheology, assembling dynamics, and function of nanoparticle arrays. For the rapid fabrication of large-area and/or patterned nanoparticle arrays, wet coating techniques, such as spin, dip, spray, gravure, slot, roll, and ink-jet coating, are promising ways for practical use in combination with an evaporation-driven self-assembly technique. We have also referred to the concept of array formation via surface modification

  3. Thermal poling of multi-wire array optical fiber

    DEFF Research Database (Denmark)

    Huang, Lin; An, Honglin; Hayashi, Juliano G.

    2018-01-01

    We demonstrate in this paper thermal poling of multi-wire array fibers, which extends poling of fibers with two anodes to similar to 50 and similar to 500 wire array anodes. The second harmonic microscopy observations show that second order nonlinearity (SON) layers are developed surrounding all...... the rings of wires in the similar to 50 anode array fiber with poling of 1.8kV, 250 degrees C and 30min duration, and the outer rings of the similar to 500 anode array fiber at lower poling temperature. Our simulations based on a two-dimensional charge dynamics model confirm this can be explained...

  4. Towards Memristive Dynamic Adaptive Neural Network Arrays

    Science.gov (United States)

    2016-03-17

    Memories,” in Proc. of International Symposium on Circuits and Systems (ISCAS), Rio de Janeiro , Brazil, May, 2011. 9. Q. Xia, W. Robinett, et al...network’s outputs fare with the given inputs. The EO then generates an initial population of random networks, and gradually evolves the population

  5. Photonic Crystal Nanocavity Arrays

    National Research Council Canada - National Science Library

    Altug, Hatice; Vuckovic, Jelena

    2006-01-01

    We recently proposed two-dimensional coupled photonic crystal nanocavity arrays as a route to achieve a slow-group velocity of light in all crystal directions, thereby enabling numerous applications...

  6. Flexible retinal electrode array

    Science.gov (United States)

    Okandan, Murat [Albuquerque, NM; Wessendorf, Kurt O [Albuquerque, NM; Christenson, Todd R [Albuquerque, NM

    2006-10-24

    An electrode array which has applications for neural stimulation and sensing. The electrode array can include a large number of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. The electrode array can be formed from a combination of bulk and surface micromachining, with electrode tips that can include an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis where the electrodes can be tailored to provide a uniform gentle contact pressure with optional sensing of this contact pressure at one or more of the electrodes.

  7. Protein Functionalized Nanodiamond Arrays

    Directory of Open Access Journals (Sweden)

    Liu YL

    2010-01-01

    Full Text Available Abstract Various nanoscale elements are currently being explored for bio-applications, such as in bio-images, bio-detection, and bio-sensors. Among them, nanodiamonds possess remarkable features such as low bio-cytotoxicity, good optical property in fluorescent and Raman spectra, and good photostability for bio-applications. In this work, we devise techniques to position functionalized nanodiamonds on self-assembled monolayer (SAMs arrays adsorbed on silicon and ITO substrates surface using electron beam lithography techniques. The nanodiamond arrays were functionalized with lysozyme to target a certain biomolecule or protein specifically. The optical properties of the nanodiamond-protein complex arrays were characterized by a high throughput confocal microscope. The synthesized nanodiamond-lysozyme complex arrays were found to still retain their functionality in interacting with E. coli.

  8. Expandable LED array interconnect

    Science.gov (United States)

    Yuan, Thomas Cheng-Hsin; Keller, Bernd

    2011-03-01

    A light emitting device that can function as an array element in an expandable array of such devices. The light emitting device comprises a substrate that has a top surface and a plurality of edges. Input and output terminals are mounted to the top surface of the substrate. Both terminals comprise a plurality of contact pads disposed proximate to the edges of the substrate, allowing for easy access to both terminals from multiple edges of the substrate. A lighting element is mounted to the top surface of the substrate. The lighting element is connected between the input and output terminals. The contact pads provide multiple access points to the terminals which allow for greater flexibility in design when the devices are used as array elements in an expandable array.

  9. Battery Charge Equalizer with Transformer Array

    Science.gov (United States)

    Davies, Francis

    2013-01-01

    High-power batteries generally consist of a series connection of many cells or cell banks. In order to maintain high performance over battery life, it is desirable to keep the state of charge of all the cell banks equal. A method provides individual charging for battery cells in a large, high-voltage battery array with a minimum number of transformers while maintaining reasonable efficiency. This is designed to augment a simple highcurrent charger that supplies the main charge energy. The innovation will form part of a larger battery charge system. It consists of a transformer array connected to the battery array through rectification and filtering circuits. The transformer array is connected to a drive circuit and a timing and control circuit that allow individual battery cells or cell banks to be charged. The timing circuit and control circuit connect to a charge controller that uses battery instrumentation to determine which battery bank to charge. It is important to note that the innovation can charge an individual cell bank at the same time that the main battery charger is charging the high-voltage battery. The fact that the battery cell banks are at a non-zero voltage, and that they are all at similar voltages, can be used to allow charging of individual cell banks. A set of transformers can be connected with secondary windings in series to make weighted sums of the voltages on the primaries.

  10. Generalized speed and cost rate in transitionless quantum driving

    Science.gov (United States)

    Xu, Zhen-Yu; You, Wen-Long; Dong, Yu-Li; Zhang, Chengjie; Yang, W. L.

    2018-03-01

    Transitionless quantum driving, also known as counterdiabatic driving, is a unique shortcut technique to adiabaticity, enabling a fast-forward evolution to the same target quantum states as those in the adiabatic case. However, as nothing is free, the fast evolution is obtained at the cost of stronger driving fields. Here, given the system initially gets prepared in equilibrium states, we construct relations between the dynamical evolution speed and the cost rate of transitionless quantum driving in two scenarios: one that preserves the transitionless evolution for a single energy eigenstate (individual driving), and the other that maintains all energy eigenstates evolving transitionlessly (collective driving). Remarkably, we find that individual driving may cost as much as collective driving, in contrast to the common belief that individual driving is more economical than collective driving in multilevel systems. We then present a potentially practical proposal to demonstrate the above phenomena in a three-level Landau-Zener model using the electronic spin system of a single nitrogen-vacancy center in diamond.

  11. Rod drive and latching mechanism

    International Nuclear Information System (INIS)

    Veronesi, L.; Sherwood, D.G.

    1982-01-01

    Hydraulic drive and latching mechanisms for driving reactivity control mechanisms in nuclear reactors are described. Preferably, the pressurized reactor coolant is utilized to raise the drive rod into contact with and to pivot the latching mechanism so as to allow the drive rod to pass the latching mechanism. The pressure in the housing may then be equalized which allows the drive rod to move downwardly into contact with the latching mechanism but to hold the shaft in a raised position with respect to the reactor core. Once again, the reactor coolant pressure may be utilized to raise the drive rod and thus pivot the latching mechanism so that the drive rod passes above the latching mechanism. Again, the mechanism pressure can be equalized which allows the drive rod to fall and pass by the latching mechanism so that the drive rod approaches the reactor core. (author)

  12. A rotary drive

    International Nuclear Information System (INIS)

    Causer, R.

    1983-01-01

    A rotary drive for a manipulator or teleoperator comprises a ring member freely rotatable about an eccentric boss extending from an input driver shaft. The ring member has a tapered rim portion wedged between two resiliently biassed friction rings of larger diameter than the ring member and coaxial with the driver shaft, and the ring member is rotatably connected to an output driven shaft. The rotary drive provides a considerable velocity ratio, and also provides a safety feature in that friction between the rim portion and the friction rings only causes rotation of the driven shaft if the load on the driven shaft is less than a certain limiting value. This limiting value may be varied by adjusting the resilient bias on the friction rings. (author)

  13. Driving and engine cycles

    CERN Document Server

    Giakoumis, Evangelos G

    2017-01-01

    This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

  14. Drive-by-Downloads

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. LOADING OF MECHANICAL TRANSMISSION OF TROLLEYBUS TRACTION DRIVING GEAR

    Directory of Open Access Journals (Sweden)

    A. I. Safonov

    2009-01-01

    Full Text Available The paper analyzes factors that determine dynamic loads of mechanical transmission of trolleybus traction driving gear. The paper proposes a methodology for determination of calculative moments of loading transmission elements. Results of the research are analyzed and recommendations on  dynamic reduction of trolleybus transmission are given in the paper. 

  16. Rf drive system for the CEBAF superconducting cavities

    International Nuclear Information System (INIS)

    Fugitt, J.A.; Moore, T.L.

    1986-01-01

    To obtain the maximum accelerating gradient, the CEBAF RF system uses an individually controlled RF drive chain for each superconducting cavity. This allows one to adjust each cavity to its individual maximum field. Due to material purity and manufacturing tolerances of the cavities, it is expected that this maximum value will be distributed over an almost 2 to 1 gradient range. The requirement for precise individual phase and gradient control of 420 superconducting accelerating cavities, is accomplished through the use of individual fault tolerant RF drive chains and self monitoring control electronics. This might be thought of as the Phased Array approach to accelerator RF systems

  17. Sex Chromosome Drive

    OpenAIRE

    Helleu, Quentin; Gérard, Pierre R.; Montchamp-Moreau, Catherine

    2015-01-01

    Sex chromosome drivers are selfish elements that subvert Mendel's first law of segregation and therefore are overrepresented among the products of meiosis. The sex-biased progeny produced then fuels an extended genetic conflict between the driver and the rest of the genome. Many examples of sex chromosome drive are known, but the occurrence of this phenomenon is probably largely underestimated because of the difficulty to detect it. Remarkably, nearly all sex chromosome drivers are found in t...

  18. Driving electrostatic transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed...

  19. Design Drives: materials innovation

    OpenAIRE

    Oliver, Raymond; Toomey, Anne

    2010-01-01

    Design Drives Materials Innovation‘ outlines the potential of a D:STEM (Design, Science, Technology, Engineering amd Mathematics) approach to combining traditionally different fields through design-led, needs driven and technology anchored future products using electro/photo/bio-active polymers in physical formats defined in ‚dots, lines, surfaces and structures‘.It also identifies Ambient Assisted Living as a key driver for future applications.

  20. [Automobile driving capacity in dementia].

    Science.gov (United States)

    Seeger, Rolf

    2015-04-01

    Dementia influences at an early stage the driving aptitude of motor vehicle steering persons. Every year in Switzerland, around 16'000 driving permit holders suffer newly from dementia; therefore the driving aptitude is questioned, especially because of possibly limited executive functions. Individuals with early-stage dementia often may show a dangerous driving stile. However, a mild dementia does not a priori exclude the driving aptitude, and less than half of these drivers can continue driving for another 1 - 3 years. In contrast, there is no further driving aptitude in presence of moderate dementia. In the assessment of driving aptitude, the underlying cause of dementia is always taken into account. Cognitive short tests such as the Mini-Mental Status Exam, Clock Drawing Test and Trail-Making Test are not suitable to make reliable statements about the aptitude to drive, but these tests are very important for the initial diagnosis of dementia in primary care practice and can lead the way for further examination concerning driving aptitude. The legally prescribed regular check-up for motorists aged over 70 years in Switzerland provides an ideal opportunity for early detection of incipient dementia. The practical procedure for the assessment of aptitude to drive in the primary care practice is presented. The physician-guided on-road driving test represents a meaningful, practical and relatively cost-effective tool for the evaluation of driving aptitude in cases of doubt.

  1. Parkinson's disease and driving ability.

    Science.gov (United States)

    Singh, Rajiv; Pentland, Brian; Hunter, John; Provan, Frances

    2007-04-01

    To explore the driving problems associated with Parkinson's disease (PD) and to ascertain whether any clinical features or tests predict driver safety. The driving ability of 154 individuals with PD referred to a driving assessment centre was determined by a combination of clinical tests, reaction times on a test rig and an in-car driving test. The majority of cases (104, 66%) were able to continue driving although 46 individuals required an automatic transmission and 10 others needed car modifications. Ability to drive was predicted by the severity of physical disease, age, presence of other associated medical conditions, particularly dementia, duration of disease, brake reaction, time on a test rig and score on a driving test (all pfeatures in distinguishing safety to drive were severe physical disease (Hoehn and Yahr stage 3), reaction time, moderate disease associated with another medical condition and high score on car testing. Most individuals with PD are safe to drive, although many benefit from car modifications or from using an automatic transmission. A combination of clinical tests and in-car driving assessment will establish safety to drive, and a number of clinical correlates can be shown to predict the likely outcome and may assist in the decision process. This is the largest series of consecutive patients seen at a driving assessment centre reported to date, and the first to devise a scoring system for on-road driving assessment.

  2. Control rod drives

    International Nuclear Information System (INIS)

    Sato, Takao; Arita, Setsuo; Mizuno, Katsuhiro.

    1986-01-01

    Purpose: To enable fine positioning by using an induction motor of a simple structure as a driving source and thereby improve the reliability of control rod drives. Constitution: A step actuator is directly coupled with an induction motor, in which the induction motor is connected by way of a pulse driving control circuit to an AC power source, while the step actuator is connected to a DC power source. When a thyristor is turned ON, the motor outputs a positive torque and rotates and starts to rotate in the forward direction. When the other thyristor is turned ON, the motor is applied with braking by a reverse excitation in a manner equivalent to the change for the exciting phase sequence. When the speed is lowered to a predetermined value, braking is actuated by the torque of the step actuator and the motor stops at a zero position or balanced position. In this way, braking is actuated from the decelerating step to the stopping with no abrasion and a highly accurate positioning is possible due to the characteristics of the step actuator. (Horiuchi, T.)

  3. Control rod drive

    International Nuclear Information System (INIS)

    Watando, Kosaku; Tanaka, Yuzo; Mizumura, Yasuhiro; Hosono, Kazuya.

    1975-01-01

    Object: To provide a simple and compact construction of an apparatus for driving a drive shaft inside with a magnetic force from the outside of the primary system water side. Structure: The weight of a plunger provided with an attraction plate is supported by a plunger lift spring means so as to provide a buffer action at the time of momentary movement while also permitting the load on lift coil to be constituted solely by the load on the drive shaft. In addition, by arranging the attraction plate and lift coil so that they face each other with a small gap there-between, it is made possible to reduce the size and permit efficient utilization of the attracting force. Because of the small size, cooling can be simply carried out. Further, since there is no mechanical penetration portion, there is no possibility of leakage of the primary system water. Furthermore, concentration of load on a latch pin is prevented by arranging so that with a structure the load of the control rod to be directly beared through the scrum latch. (Kamimura, M.)

  4. Neuromorphic meets neuromechanics, part II: the role of fusimotor drive.

    Science.gov (United States)

    Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Joon Sohn, Won; Loeb, Gerald E; Sanger, Terence D; Valero-Cuevas, Francisco J

    2017-04-01

    We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bi-directional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our Neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function-and its pathologies such as dystonia and spasticity. In

  5. Neuromorphic meets neuromechanics, part II: the role of fusimotor drive

    Science.gov (United States)

    Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Sohn, Won Joon; Loeb, Gerald E.; Sanger, Terence D.; Valero-Cuevas, Francisco J.

    2017-04-01

    Objective. We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. Approach. As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bi-directional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. Main results. We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. Significance. We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our Neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function—and its

  6. Dynamic Flaps Electronic Scan Antenna

    National Research Council Canada - National Science Library

    Gonzalez, Daniel

    2000-01-01

    A dynamic FLAPS(TM) electronic scan antenna was the focus of this research. The novelty S of this SBIR resides in the use of plasma as the main component of this dynamic X-Band phased S array antenna...

  7. Effects of trait anger, driving anger, and driving experience on dangerous driving behavior: A moderated mediation analysis.

    Science.gov (United States)

    Ge, Yan; Zhang, Qian; Zhao, Wenguo; Zhang, Kan; Qu, Weina

    2017-11-01

    To explore the effect of anger behind the wheel on driving behavior and accident involvement has been the subject of many studies. However, few studies have explored the interaction between anger and driving experience on dangerous driving behavior. This study is a moderated mediation analysis of the effect of trait anger, driving anger, and driving experience on driving behavior. A sample of 303 drivers was tested using the Trait Anger Scale (TAS), the Driving Anger Scale (DAS), and the Dula Dangerous Driving Index (DDDI). The results showed that trait anger and driving anger were positively correlated with dangerous driving behavior. Driving anger partially mediated the effect of trait anger on dangerous driving behavior. Driving experience moderated the relationship between trait anger and driving anger. It also moderated the effect of driving anger on dangerous driving behavior. These results suggest that drivers with more driving experience may be safer as they are not easily irritated during driving. © 2017 Wiley Periodicals, Inc.

  8. Low Sex Drive in Women

    Science.gov (United States)

    Low sex drive in women Overview Women's sexual desires naturally fluctuate over the years. Highs and lows commonly coincide ... used for mood disorders also can cause low sex drive in women. If your lack of interest ...

  9. Marijuana and actual driving performance

    Science.gov (United States)

    1993-11-01

    This report concerns the effects of marijuana smoking on actual driving performance. It presents the results of one pilot and three actual driving studies. The pilot study's major purpose was to establish the THC dose current marijuana users smoke to...

  10. Testing of focal plane arrays

    International Nuclear Information System (INIS)

    Merriam, J.D.

    1988-01-01

    Problems associated with the testing of focal plane arrays are briefly examined with reference to the instrumentation and measurement procedures. In particular, the approach and instrumentation used as the Naval Ocean Systems Center is presented. Most of the measurements are made with flooded illumination on the focal plane array. The array is treated as an ensemble of individual pixels, data being taken on each pixel and array averages and standard deviations computed for the entire array. Data maps are generated, showing the pixel data in the proper spatial position on the array and the array statistics

  11. SEP solar array Shuttle flight experiment

    Science.gov (United States)

    Elms, R. V., Jr.; Young, L. E.; Hill, H. C.

    1981-01-01

    An experiment to verify the operational performance of a full-scale Solar Electric Propulsion (SEP) solar array is described. Scheduled to fly on the Shuttle in 1983, the array will be deployed from the bay for ten orbits, with dynamic excitation to test the structural integrity being furnished by the Orbiter verniers; thermal, electrical, and sun orientation characteristics will be monitored, in addition to safety, reliability, and cost effective performance. The blanket, with aluminum and glass as solar cell mass simulators, is 4 by 32 m, with panels (each 0.38 by 4 m) hinged together; two live Si cell panels will be included. The panels are bonded to stiffened graphite-epoxy ribs and are storable in a box in the bay. The wing support structure is detailed, noting the option of releasing the wing into space by use of the Remote Manipulator System if the wing cannot be refolded. Procedures and equipment for monitoring the array behavior are outlined, and comprise both analog data and TV recording for later playback and analysis. The array wing experiment will also aid in developing measurement techniques for large structure dynamics in space.

  12. Nuclear refueling platform drive system

    International Nuclear Information System (INIS)

    Busch, F.R.; Faulstich, D.L.

    1992-01-01

    This patent describes a drive system. It comprises: a gantry including a bridge having longitudinal and transverse axes and supported by spaced first and second end frames joined to fist and second end frames joined to first and second drive trucks for moving the bridge along the transverse axis; first means for driving the first drive truck; second means for driving the second drive truck being independent from the first driving means; and means for controlling the first and second driving means for reducing differential transverse travel between the first and second drive trucks, due to a skewing torque acting on the bridge, to less than a predetermined maximum, the controlling means being in the form of an electrical central processing unit and including: a closed-loop first velocity control means for controlling velocity of the first drive truck by providing a first command signal to the first driver means; a close loop second velocity control means for controlling velocity of the second drive truck by providing a second command signal to the second driving means; and an auxiliary closed-loop travel control means

  13. Photovoltaic array reliability optimization

    Science.gov (United States)

    Ross, R. G., Jr.

    1982-01-01

    An overview of the photovoltaic array reliability problem is presented, and a high reliability/minimum cost approach to this problem is presented. Design areas covered are cell failure, interconnect fatigue, and electrical insulation breakdown, and three solution strategies are discussed. The first involves controlling component failures in the solar cell (cell cracking, cell interconnects) and at the module level (must be statistically treated). Second, a fault tolerant circuit is designed which reduces array degradation, improves module yield losses, and controls hot-spot heating. Third, cost optimum module replacement strategies are also effective in reducing array degradation. This can be achieved by minimizing the life-cycle energy cost of the photovoltaic system. The integration of these solutions is aimed at reducing the 0.01% failure rate.

  14. Coaxial phased array antenna

    Science.gov (United States)

    Ellis, H., Jr.

    1980-08-01

    A coaxial antenna array for communicating circularly polarized electromagnetic radiation is disclosed. A pair of open ended antenna cavities is coaxially constructed and operates by excitation of linear radiation elements arranged within each of the cavities. A pair of crossed dipole radiation devices is centered within the inner cavity and operated by means of a phase shifting network circuit to transmit as well as receive circularly polarized radiation. Four monopole radiation devices are symmetrically arranged to operate in the outer cavity in phase quadrature by means of the phase shifting network circuit to both transmit and receive circularly polarized electromagnetic radiation. Combined operation of the two antenna cavities with a 180 deg phase differential between the fields related to the two antenna cavities provides a broad beam, relatively wide frequency bandwidth communication capability. Particular embodiments disclosed feature a generally square cavity array as well as a circular cavity array.

  15. Micromachined droplet ejector arrays

    Science.gov (United States)

    Perçin, Gökhan; Yaralioglu, Göksenin G.; Khuri-Yakub, Butrus T.

    2002-12-01

    In this article we present a micromachined flextensional droplet ejector array used to eject liquids. By placing a fluid behind one face of a vibrating circular plate that has an orifice at its center, we achieve continuous ejection of the fluid. We present results of ejection of water and isopropanol. The ejector is harmless to sensitive fluids and can be used to eject fuels, organic polymers, photoresists, low-k dielectrics, adhesives, and chemical and biological samples. Micromachined two-dimensional array flextensional droplet ejectors were realized using planar silicon micromachining techniques. Typical resonant frequency of the micromachined device ranges from 400 kHz to 4.5 MHz. The ejections of water through a 4 μm diameter orifice at 3.45 MHz and a 10 μm diameter orifice at 2.15 MHz were demonstrated by using the developed micromachined two-dimensional array ejectors.

  16. Dynamical entanglement formation and dissipation effects in two double quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Contreras-Pulido, L D [Centro de Investigacion CientIfica y de Educacion Superior de Ensenada, Apartado Postal 2732, Ensenada, BC 22860 (Mexico); Rojas, F [Departamento de Fisica Teorica, Centro de Ciencias de la Materia Condensada, Universidad Nacional Autonoma de Mexico, Ensenada, Baja California 22800 (Mexico)

    2006-11-01

    We study the static and dynamic formation of entanglement in charge states of a two double quantum dot array with two mobile electrons under the effect of an external driving field. We include dissipation via contact with a phonon bath. By using the density matrix formalism and an open quantum system approach, we describe the dynamical behaviour of the charge distribution (polarization), concurrence (measure of the degree of entanglement) and Bell state probabilities (two qubit states with maximum entanglement) of such a system, including the role of dot asymmetry and temperature effects. Our results show that it is possible to obtain entangled states as well as a most probable Bell state, which can be controlled by the driving field. We also evaluate how the entanglement formation based on charge states deteriorates as the temperature or asymmetry increases.

  17. Wire Array Photovoltaics

    Science.gov (United States)

    Turner-Evans, Dan

    Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar. Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry. The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires. Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction

  18. Tilted hexagonal post arrays: DNA electrophoresis in anisotropic media

    Science.gov (United States)

    Chen, Zhen; Dorfman, Kevin D.

    2013-01-01

    Using Brownian dynamics simulations, we show that DNA electrophoresis in a hexagonal array of micron-sized posts changes qualitatively when the applied electric field vector is not coincident with the lattice vectors of the array. DNA electrophoresis in such “tilted” post arrays is superior to the standard “un-tilted” approach; while the time required to achieve a resolution of unity in a tilted post array is similar to an un-tilted array at a low electric field strengths, this time (i) decreases exponentially with electric field strength in a tilted array and (ii) increases exponentially with electric field strength in an un-tilted array. Although the DNA dynamics in a post array are complicated, the electrophoretic mobility results indicate that the “free path”, i.e., the average distance of ballistic trajectories of point sized particles launched from random positions in the unit cell until they intersect the next post, is a useful proxy for the detailed DNA trajectories. The analysis of the free path reveals a fundamental connection between anisotropy of the medium and DNA transport therein that goes beyond simply improving the separation device. PMID:23868490

  19. Offset Compound Gear Drive

    Science.gov (United States)

    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.

  20. Measurement of Driving Terms

    CERN Document Server

    Schmidt, F; Faus-Golfe, A

    2001-01-01

    In 2000 a series of MDs has been performed at the SPS to measure resonance driving terms. Theory predicts that these terms can be determined by harmonic analysis of BPM data recorded after applying single kicks at various amplitudes. Strong sextupoles were introduced to create a sizeable amount of nonlinearities. Experiments at injection energy (26 GeV) with single bunch as well as one experiment at 120 GeV with 84 bunches were carried out. The expected nonlinear content is compared to the experimenteal observation.

  1. Electrical machines and drives

    CERN Document Server

    Hindmarsh, John

    2002-01-01

    Recent years have brought substantial developments in electrical drive technology, with the appearance of highly rated, very-high-speed power-electronic switches, combined with microcomputer control systems.This popular textbook has been thoroughly revised and updated in the light of these changes. It retains its successful formula of teaching through worked examples, which are put in context with concise explanations of theory, revision of equations and discussion of the engineering implications. Numerous problems are also provided, with answers supplied.The third edition in

  2. Electrical machines & drives

    CERN Document Server

    Hammond, P

    1985-01-01

    Containing approximately 200 problems (100 worked), the text covers a wide range of topics concerning electrical machines, placing particular emphasis upon electrical-machine drive applications. The theory is concisely reviewed and focuses on features common to all machine types. The problems are arranged in order of increasing levels of complexity and discussions of the solutions are included where appropriate to illustrate the engineering implications. This second edition includes an important new chapter on mathematical and computer simulation of machine systems and revised discussions o

  3. Driving electrostatic transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed......, and a high voltage attenuation interface for an audio analyzer is presented. THD below 0:1% is reported....

  4. Force sensitive carbon nanotube arrays for biologically inspired airflow sensing

    International Nuclear Information System (INIS)

    Maschmann, Matthew R; Ehlert, Gregory J; Baur, Jeffery W; Dickinson, Ben

    2012-01-01

    The compressive electromechanical response of aligned carbon nanotube (CNT) arrays is evaluated for use as an artificial hair sensor (AHS) transduction element. CNT arrays with heights of 12, 75, and 225 µm are examined. The quasi-static and dynamic sensitivity to force, response time, and signal drift are examined within the range of applied stresses predicted by a mechanical model applicable to the conceptual CNT array-based AHS (0–1 kPa). Each array is highly sensitive to compressive loading, with a maximum observed gauge factor of 114. The arrays demonstrate a repeatable response to dynamic cycling after a break-in period of approximately 50 cycles. Utilizing a four-wire measurement electrode configuration, the change in contact resistance between the array and the electrodes is observed to dominate the electromechanical response of the arrays. The response time of the CNT arrays is of the order of 10 ms. When the arrays are subjected to constant stress, mechanical creep is observed that results in a signal drift that generally diminishes the responsiveness of the arrays, particularly at stress approaching 1 kPa. The results of this study serve as a preliminary proof of concept for utilizing CNT arrays as a transduction mechanism for a proposed artificial hair sensor. Such a low profile and light-weight flow sensor is expected to have application in a number of applications including navigation and state awareness of small air vehicles, similar in function to natural hair cell receptors utilized by insects and bats. (paper)

  5. A review of array radars

    Science.gov (United States)

    Brookner, E.

    1981-10-01

    Achievements in the area of array radars are illustrated by such activities as the operational deployment of the large high-power, high-range-resolution Cobra Dane; the operational deployment of two all-solid-state high-power, large UHF Pave Paws radars; and the development of the SAM multifunction Patriot radar. This paper reviews the following topics: array radars steered in azimuth and elevation by phase shifting (phase-phase steered arrays); arrays steered + or - 60 deg, limited scan arrays, hemispherical coverage, and omnidirectional coverage arrays; array radars steering electronically in only one dimension, either by frequency or by phase steering; and array radar antennas which use no electronic scanning but instead use array antennas for achieving low antenna sidelobes.

  6. Glaucoma and Driving: On-Road Driving Characteristics.

    Science.gov (United States)

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

    2016-01-01

    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. 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. 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. 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.

  7. Control rod drives

    International Nuclear Information System (INIS)

    Oonuki, Koji.

    1981-01-01

    Purpose: To increase the driving speed of control rods at rapid insertion with an elongate control rod and an extension pipe while ensuring sufficient buffering performance in a short buffering distance, by providing a plurality of buffers to an extension pipe between a control rod drive source and a control rod in LMFBR type reactor. Constitution: First, second and third buffers are respectively provided to an acceleration piston, an extension pipe and a control rod respectively and the insertion positions for each of the buffers are displaced orderly from above to below. Upon disconnection of energizing current for an electromagnet, the acceleration piston, the extension pipe and the control rod are rapidly inserted in one body. The first, second and third buffers are respectively actuated at each of their falling strokes upon rapid insertion respectively, and the acceleration piston, the extension pipe and the control rod receive the deceleration effect in the order correspondingly. Although the compression force is applied to the control rod only near the stroke end, it does not cause deformation. (Kawakami, Y.)

  8. Polar drive on OMEGA

    Directory of Open Access Journals (Sweden)

    Radha P.B.

    2013-11-01

    Full Text Available 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.

  9. Array Theory and Nial

    DEFF Research Database (Denmark)

    Falster, Peter; Jenkins, Michael

    1999-01-01

    This report is the result of collaboration between the authors during the first 8 months of 1999 when M. Jenkins was visiting professor at DTU. The report documents the development of a tool for the investigation of array theory concepts and in particular presents various approaches to choose...

  10. A fast 8-channel wavelength switching DFB diode laser array based on reconstruction-equivalent-chirp technique

    Science.gov (United States)

    Li, Wei; Wang, Yingying; Du, Yinchao; Du, Weikang; Zhao, Guowang; Fang, Tao

    2018-01-01

    We propose a new method to investigate fast wavelength switching, which consists of control circuit, driving circuit and 8-channel DFB laser array using reconstruction-equivalent-chirp technique. The control circuit is in charge of selecting required lasers to switch wavelength, the driving circuit supply adjustable and stable direct current to the DFB laser arrays. Experimental results show that wavelength switching time of 8 channels is about 500ns and stability of laser output is promised.

  11. Theoretical model and experimental verification on the PID tracking method using liquid crystal optical phased array

    Science.gov (United States)

    Wang, Xiangru; Xu, Jianhua; Huang, Ziqiang; Wu, Liang; Zhang, Tianyi; Wu, Shuanghong; Qiu, Qi

    2017-02-01

    Liquid crystal optical phased array (LC-OPA) has been considered with great potential on the non-mechanical laser deflector because it is fabricated using photolithographic patterning technology which has been well advanced by the electronics and display industry. As a vital application of LC-OPA, free space laser communication has demonstrated its merits on communication bandwidth. Before data communication, ATP (acquisition, tracking and pointing) process costs relatively long time to result in a bottle-neck of free space laser communication. Meanwhile, dynamic real time accurate tracking is sensitive to keep a stable communication link. The electro-optic medium liquid crystal with low driving voltage can be used as the laser beam deflector. This paper presents a fast-track method using liquid crystal optical phased array as the beam deflector, CCD as a beacon light detector. PID (Proportion Integration Differentiation) loop algorithm is introduced as the controlling algorithm to generate the corresponding steering angle. To achieve the goal of fast and accurate tracking, theoretical analysis and experimental verification are demonstrated that PID closed-loop system can suppress the attitude random vibration. Meanwhile, theoretical analysis shows that tracking accuracy can be less than 6.5μrad, with a relative agreement with experimental results which is obtained after 10 adjustments that the tracking accuracy is less than12.6μrad.

  12. Wire-Array Precursor Plasma Interactions With On-Axis Foam Targets

    Science.gov (United States)

    Palmer, J. B. A.; Bland, S. N.

    2005-10-01

    The Dynamic Hohlraum (DH) Z-pinch on Z at Sandia National Laboratory (SNL) has been used to drive Inertial Confinement Fusion (ICF) and High Energy Density Physics (HEDP) relevant experiments. The power pulse from the DH cannot yet be reproduced using codes that can reproduce the performance of a Vacuum Hohlraum (VH) configuration on Z. Unlike the VH the DH has a low-density CH foam cylinder placed on the array axis. Production of precursor plasma, prior to the main implosion, is not included in the codes. This plasma is accelerated towards the array axis by the global J x B force and impacts onto the on-axis target. This bombardment alters the foam in various ways. Experiments have been performed on the 1 MA MAGPIE generator at Imperial College, London, to investigate the effect of this precursor bombardment. Diagnostics used were point-projection radiography with x-pinches, x-ray emission framing cameras, shadowgraphy and photoconduction diodes. Results show ablation of low-density plasma from the foam surface and compression of the foam by precursor pressure. Research sponsored by AWE, SNL, the SSAA program of NNSA under DOE Cooperative Agreement DE-FC03-02NA00057.

  13. Novel Spherical Robot with Hybrid Pendulum Driving Mechanism

    Directory of Open Access Journals (Sweden)

    Sung-Su Ahn

    2014-11-01

    Full Text Available As regards omnidirectional driving, conventional one- and two-pendulum spherical robots have a limited capability due to a limited pendulum motion range. In particular, such robots cannot move from a stationary state in a parallel direction to the center horizontal axis to which the pendulums are attached. Thus, to overcome the limited driving capability of one- and two-pendulum driven spherical robots, a passive version of a spherical robot, called KisBot II, was developed with a curved two-pendulum driving mechanism operated by a joystick. However, this paper presents an active upgraded version of KisBot II that includes a DSP-based control system and Task-based software architecture for driving control and data communication, respectively. A dynamic model for two-pendulum driving is derived using the Lagrange equation method, and a feedback controller for linear driving using two pendulums is then constructed based on the dynamic model. Experiments with several motions verify the driving efficiency of the proposed novel spherical robot.

  14. Acceleration of electrons in the vicinity of a lower hybrid waveguide array

    International Nuclear Information System (INIS)

    Fuchs, V.; Goniche, M.; Demers, Y.; Jacquet, P.; Mailloux, J.

    1996-01-01

    The interaction of tokamak plasma edge electrons with the electric near field generated by a lower hybrid slow wave antenna is studied. Antenna field spectra of interest for current drive and/or plasma heating have lobes at high-n parallel values (n parallel approx-gt 30) intense enough for resonant acceleration of the relatively cold (∼25 eV) edge electrons. For waveguide electric fields, typically around 3 kV/cm, the higher-order modes overlap in the phase-space [B. V. Chirikov, Phys. Rep. 52, 263 (1979)], so that electron global stochasticity is induced. For Tokamak de Varennes (TdeV) [Dacute ecoste et al., Phys. Plasmas 1, 1497 (1994)] conditions and for 90 degree waveguide phasing, the stochastic limit in the current drive direction is about 2 keV, determined by the last overlapping mode. The progress of electrons through accessible phase space is very efficient: the TdeV 32 waveguide array can accelerate the electrons to the possible limit. An area-preserving map is derived to study the electron dynamics. Surface-of-section plots fully confirm the resonant wave-particle nature of the interaction. copyright 1996 American Institute of Physics

  15. Flywheel driving system study

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Seop Koh; Choi, Jae Ho; Jeoung, Hwan Myoung; Lee, Byoung Gu [Chungbuk National University, Cheongju (Korea)

    1999-03-01

    In this research, the superconductivity flywheel energy storage system, which transform the D.C electric power to mechanical energy by rotating the flywheel very high speed and vice verse, is designed and constructed. The system has a power converter and BLDC motor as a driver. In order to increase the efficiency of the motor, a special Halbach array of Nd-Fe-B permanent magnet, which remnant magnetic flux density is about 1.2(T), is used. The developed power converter employed PLL and Sin ROM for the accurate phase detection at the very high speed, and sine wave control of the input current is achieved by using hysteresis current control techniques. The flywheel energy storage system is experimental using both the superconducting bearing and ball bearing. (author). 20 refs., 55 figs., 4 tabs.

  16. Driving citations and aggressive behavior.

    Science.gov (United States)

    Sansone, Randy A; Leung, Justin S; Wiederman, Michael W

    2012-01-01

    Anger and driving have been examined in a number of studies of aggressive drivers and in drivers with road rage using various psychological and environmental study variables. However, we are not aware of any study that has examined the number of driving citations (an indication of problematic driving) and various forms of anger not related to driving. Using a cross-sectional approach in a consecutive sample of 331 respondents (68% female), we surveyed participants about the number of past driving citations, not necessarily convictions, and 21 aggressive behaviors using the Aggressive Behavior Questionnaire. The number of driving citations demonstrated a statistically significant correlation with the number of aggressive behaviors in the 21-item Aggressive Behavior Questionnaire. There were no differences between men and women. As for specific aggressive behaviors, the number of driving citations was statistically significantly related to punching a wall when angry, causing and getting into a bar fight, getting into fistfights (not in a bar), causing someone to have an accident, and intentionally running someone off the road. The number of driving citations, an indication of problematic driving, appears to be related to generally aggressive behavior. Findings indicate that if aggression plays a role in problematic driving, it is likely not limited to the road.

  17. Design and evaluation of a feedback based phased array system for ultrasound surgery.

    Science.gov (United States)

    Daum, D R; Buchanan, M T; Fjield, T; Hynynen, K

    1998-01-01

    A driving system has been designed for phased array ultrasound applicators. The system is designed to-operate in the bandwidth 1.2 to 1.8 MHz, with independent channel power control up to 60 W (8 bit resolution) for each array element. To reduce power variation between elements, the system utilizes switching regulators in a feedback loop to automatically adjust the DC supply of a class D/E power converter. This feedback reduces the RF electrical power variation from 20% to 1% into a 16 element array. DC-to-RF efficiencies close to 70% for all power levels eliminates the need for large heat sinks. In addition to power control, each channel may be phase shifted 360 degrees with a minimum of 8 bit resolution. To ensure proper operation while driving ultrasound arrays with varying element sizes, each RF driving channel implements phase feedback such that proper phase of the driving signal is produced either at the amplifier output before the matching circuitry or after the matching circuitry at the transducer face. This feedback has been experimentally shown to increase the focal intensities by 20 to 25% of two tested phased arrays without array calibration using a hydrophone.

  18. Reconfiguration of DNA molecular arrays driven by information relay.

    Science.gov (United States)

    Song, Jie; Li, Zhe; Wang, Pengfei; Meyer, Travis; Mao, Chengde; Ke, Yonggang

    2017-07-28

    Information relay at the molecular level is an essential phenomenon in numerous chemical and biological processes, such as intricate signaling cascades. One key challenge in synthetic molecular self-assembly is to construct artificial structures that imitate these complex behaviors in controllable systems. We demonstrated prescribed, long-range information relay in an artificial molecular array assembled from modular DNA structural units. The dynamic DNA molecular array exhibits transformations with programmable initiation, propagation, and regulation. The transformation of the array can be initiated at selected units and then propagated, without addition of extra triggers, to neighboring units and eventually the entire array. The specific information pathways by which this transformation occurs can be controlled by altering the design of individual units and the arrays. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  19. Driving without a GPS

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.

    in the best way possible; and that the differences in their knowledge systems is acknowledged and used as an asset in these international programmes. With these factors in place, on the other hand, programmes with international faculty and diverse student audiences in which this diversity is exploited...... as students as well as the lecturers themselves represent a diverse range of first languages, cultures and knowledge systems; at the same time, the teaching and learning must reach at least the same high quality standards as in more traditional mono-lingual and mono-cultural settings. For a lecturer...... in an appropriate way, may have a considerable added value that positively impacts on the knowledge, skills and competences developed by their graduates. However, lecturers often feel at a loss because they are not sure how to do this and teaching becomes like driving in unknown territory without a GPS. Based...

  20. Control rod drives

    International Nuclear Information System (INIS)

    Kono, Nobuaki.

    1987-01-01

    Purpose: To remove movable portion and improve the reliability by the direct control to coil. Constitution: Coils are disposed vertically at a predetermined interval to the outside of a control rod drive guide tube and each of the coils is adapted to be directly controlled. The coils are arranged at such an interval that a plunger laps over the vertically adjacent coils. In the case of moving the plunger upwardly, a coil just above the coil that attract the plunger is energized while the coil attracting the plunger so far is denergized. Then, the plunger is pulled up to an aimed position by repeating the procedures. In the case of moving the plunger downwardly, the procedures are conducted in the manner opposite to the above. (Kawakami, Y.)