WorldWideScience

Sample records for controlled spatial separation

  1. Tuning of the Hanle effect from EIT to EIA using spatially separated probe and control beams.

    Science.gov (United States)

    Bhattarai, Mangesh; Bharti, Vineet; Natarajan, Vasant

    2018-05-14

    We demonstrate a technique for continuous tuning of the Hanle effect from electromagnetically induced transparency (EIT) to electromagnetically induced absorption (EIA) by changing the polarization ellipticity of a control beam. In contrast to previous work in this field, we use spatially separated probe and control beams. The experiments are done using magnetic sublevels of the F g  = 4 → F e  = 5 closed hyperfine transition in the 852 nm D 2 line of 133 Cs. The atoms are contained in a room temperature vapor cell with anti-relaxation (paraffin) coating on the walls. The paraffin coating is necessary for the atomic coherence to be transported between the beams. The experimental results are supported by a density-matrix analysis of the system, which also explains the observed amplitude and zero-crossing of the resonances. Such continuous tuning of the sign of a resonance has important applications in quantum memory and other precision measurements.

  2. Plasmon interactions between gold nanoparticles in aqueous solution with controlled spatial separation

    DEFF Research Database (Denmark)

    Sendroiu, I.E.; Mertens, Stijn; Schiffrin, D.J.

    2006-01-01

    The effects of interparticle distance on the UV-visible absorption spectrum of gold nanocrystals aggregates in aqueous solution have been investigated. The aggregates were produced by ion-templated chelation of omega-mercaptocarboxylic acid ligands covalently attached to the nanoparticles surface....... Variation of the ligand chain length provides control over the interparticle separation in the aggregates. The UV-visible spectra consist typically of a single particle band and a secondary band at higher wavelengths associated with the formation of aggregates in solution. The position of the latter depends...

  3. Controlling Separation in Turbomachines

    Science.gov (United States)

    Evans, Simon; Himmel, Christoph; Power, Bronwyn; Wakelam, Christian; Xu, Liping; Hynes, Tom; Hodson, Howard

    2010-01-01

    Four examples of flow control: 1) Passive control of LP turbine blades (Laminar separation control). 2) Aspiration of a conventional axial compressor blade (Turbulent separation control). 3) Compressor blade designed for aspiration (Turbulent separation control). 4.Control of intakes in crosswinds (Turbulent separation control).

  4. Spatial scale separation in regional climate modelling

    Energy Technology Data Exchange (ETDEWEB)

    Feser, F.

    2005-07-01

    In this thesis the concept of scale separation is introduced as a tool for first improving regional climate model simulations and, secondly, to explicitly detect and describe the added value obtained by regional modelling. The basic idea behind this is that global and regional climate models have their best performance at different spatial scales. Therefore the regional model should not alter the global model's results at large scales. The for this purpose designed concept of nudging of large scales controls the large scales within the regional model domain and keeps them close to the global forcing model whereby the regional scales are left unchanged. For ensemble simulations nudging of large scales strongly reduces the divergence of the different simulations compared to the standard approach ensemble that occasionally shows large differences for the individual realisations. For climate hindcasts this method leads to results which are on average closer to observed states than the standard approach. Also the analysis of the regional climate model simulation can be improved by separating the results into different spatial domains. This was done by developing and applying digital filters that perform the scale separation effectively without great computational effort. The separation of the results into different spatial scales simplifies model validation and process studies. The search for 'added value' can be conducted on the spatial scales the regional climate model was designed for giving clearer results than by analysing unfiltered meteorological fields. To examine the skill of the different simulations pattern correlation coefficients were calculated between the global reanalyses, the regional climate model simulation and, as a reference, of an operational regional weather analysis. The regional climate model simulation driven with large-scale constraints achieved a high increase in similarity to the operational analyses for medium-scale 2 meter

  5. Spatial separation and entanglement of identical particles

    Science.gov (United States)

    Cunden, Fabio Deelan; di Martino, Sara; Facchi, Paolo; Florio, Giuseppe

    2014-04-01

    We reconsider the effect of indistinguishability on the reduced density operator of the internal degrees of freedom (tracing out the spatial degrees of freedom) for a quantum system composed of identical particles located in different spatial regions. We explicitly show that if the spin measurements are performed in disjoint spatial regions then there are no constraints on the structure of the reduced state of the system. This implies that the statistics of identical particles has no role from the point of view of separability and entanglement when the measurements are spatially separated. We extend the treatment to the case of n particles and show the connection with some recent criteria for separability based on subalgebras of observables.

  6. Entanglement between two spatially separated atomic modes

    Science.gov (United States)

    Lange, Karsten; Peise, Jan; Lücke, Bernd; Kruse, Ilka; Vitagliano, Giuseppe; Apellaniz, Iagoba; Kleinmann, Matthias; Tóth, Géza; Klempt, Carsten

    2018-04-01

    Modern quantum technologies in the fields of quantum computing, quantum simulation, and quantum metrology require the creation and control of large ensembles of entangled particles. In ultracold ensembles of neutral atoms, nonclassical states have been generated with mutual entanglement among thousands of particles. The entanglement generation relies on the fundamental particle-exchange symmetry in ensembles of identical particles, which lacks the standard notion of entanglement between clearly definable subsystems. Here, we present the generation of entanglement between two spatially separated clouds by splitting an ensemble of ultracold identical particles prepared in a twin Fock state. Because the clouds can be addressed individually, our experiments open a path to exploit the available entangled states of indistinguishable particles for quantum information applications.

  7. Spatial interference from well-separated split condensates

    International Nuclear Information System (INIS)

    Zawadzki, M. E.; Griffin, P. F.; Riis, E.; Arnold, A. S.

    2010-01-01

    We use magnetic levitation and a variable-separation dual optical plug to obtain clear spatial interference between two condensates axially separated by up to 0.25 mm - the largest separation observed with this kind of interferometer. Clear planar fringes are observed using standard (i.e., nontomographic) resonant absorption imaging. The effect of a weak inverted parabola potential on fringe separation is observed and agrees well with theory.

  8. Work control in separations facilities

    International Nuclear Information System (INIS)

    Olson, L.D.

    1990-01-01

    The topic addressed in this technical review is the development and implementation of a work control program in one of the chemical separations facilities at the Savannah River Site (SRS) in Aiken, SC. This program will be used as a pilot for the Nuclear Materials Processing Division at the site. The SRS Work Control Pilot program is based on the Institute of Nuclear Power Operations (INPO) good practices and guidelines for the conduct of maintenance and complies with SRS quality assurance and DOE orders on maintenance management. The program follows a ten-step process for control of maintenance and maintenance-related activities in a chemical separations facility. The program took the existing maintenance planning and scheduling system and upgraded it to comply with all INPO work control and related guidelines for histories, post-maintenance testing and scheduling. The development process of adapting a nuclear-related- based plan to a batch/continuous chemical separations plant was a challenge. There were many opportunities to develop improvements in performance while being creative and realistic in applying reactor maintenance technology to chemical plant maintenance. This pilot program for work control in a nonreactor nuclear facility will provide valuable information for applying a controlled maintenance process to a multiphase chemical operating plant environment

  9. Spatial and Temporal Patterns In Ecohydrological Separation

    Science.gov (United States)

    Jarvis, S. K.; Barnard, H. R.; Singha, K.; Harmon, R. E.; Szutu, D.

    2017-12-01

    The model of ecohydrological separation suggests that trees source water from a different subsurface pool than what is contributing to stream flow during dry periods, however diel fluctuations in stream flow and transpiration are tightly coupled. To better understand the mechanism of this coupling, this study examines spatiotemporal patterns in water isotopic relationships between tree, soil, and stream water. Preliminary analysis of data collected in 2015 show a trend in δ18O enrichment in xylem water, suggesting an increased reliance on enriched soil water not flowing to the stream as the growing season progresses, while xylem samples from 2016, a particularly wet year, do not have this trend. Variations in these temporal trends are explored with regard to distance from stream, aspect of hillslope, position in the watershed, size of the tree, and soil depth. Additionally, a near-stream site is examined at high resolution using water isotope data, sap flow, and electrical resistivity surveying to examine soil moisture and water use patterns across the riparian-hillslope transition.

  10. Spatially Controlled Relay Beamforming

    Science.gov (United States)

    Kalogerias, Dionysios

    This thesis is about fusion of optimal stochastic motion control and physical layer communications. Distributed, networked communication systems, such as relay beamforming networks (e.g., Amplify & Forward (AF)), are typically designed without explicitly considering how the positions of the respective nodes might affect the quality of the communication. Optimum placement of network nodes, which could potentially improve the quality of the communication, is not typically considered. However, in most practical settings in physical layer communications, such as relay beamforming, the Channel State Information (CSI) observed by each node, per channel use, although it might be (modeled as) random, it is both spatially and temporally correlated. It is, therefore, reasonable to ask if and how the performance of the system could be improved by (predictively) controlling the positions of the network nodes (e.g., the relays), based on causal side (CSI) information, and exploitting the spatiotemporal dependencies of the wireless medium. In this work, we address this problem in the context of AF relay beamforming networks. This novel, cyber-physical system approach to relay beamforming is termed as "Spatially Controlled Relay Beamforming". First, we discuss wireless channel modeling, however, in a rigorous, Bayesian framework. Experimentally accurate and, at the same time, technically precise channel modeling is absolutely essential for designing and analyzing spatially controlled communication systems. In this work, we are interested in two distinct spatiotemporal statistical models, for describing the behavior of the log-scale magnitude of the wireless channel: 1. Stationary Gaussian Fields: In this case, the channel is assumed to evolve as a stationary, Gaussian stochastic field in continuous space and discrete time (say, for instance, time slots). Under such assumptions, spatial and temporal statistical interactions are determined by a set of time and space invariant

  11. First spatial isotopic separation of relativistic uranium projectile fragments

    International Nuclear Information System (INIS)

    Magel, A.; Voss, B.; Armbruster, P.; Aumann, T.; Clerc, H.G.; Czajkowski, S.; Folger, H.; Grewe, A.; Hanelt, E.; Heinz, A.; Irnich, H.; Jong, M. de; Junghans, A.; Nickel, F.; Pfuetzner, M.; Roehl, C.; Scheidenberger, C.; Schmidt, K.H.; Schwab, W.; Steinhaeuser, S.; Suemmerer, K.; Trinder, W.; Wollnik, H.

    1994-07-01

    Spatial isotopic separation of relativistic uranium projectile fragments has been achieved for the first time. The fragments were produced in peripheral nuclear collisions and spatially separated in-flight with the fragment separator FRS at GSI. A two-fold magnetic-rigidity analysis was applied exploiting the atomic energy loss in specially shaped matter placed in the dispersive central focal plane. Systematic investigations with relativistic projectiles ranging from oxygen up to uranium demonstrate that the FRS is a universal and powerful facility for the production and in-flight separation of monoisotopic, exotic secondary beams of all elements up to Z=92. This achievement has opened a new area in heavy-ion research and applications. (orig.)

  12. Some thoughts on separation control strategies

    Indian Academy of Sciences (India)

    Flow separation generally leads to increased energy losses, instability and so ... Separation control strategy often refers to a clever (or intelligent) fluid ... bubble will have a certain influence, directly or indirectly, on the development of the shear.

  13. Simultaneous Multiple-Location Separation Control

    Science.gov (United States)

    Greenblatt, David (Inventor)

    2009-01-01

    A method of controlling a shear layer for a fluid dynamic body introduces first periodic disturbances into the fluid medium at a first flow separation location. Simultaneously, second periodic disturbances are introduced into the fluid medium at a second flow separation location. A phase difference between the first and second periodic disturbances is adjusted to control flow separation of the shear layer as the fluid medium moves over the fluid dynamic body.

  14. Plasmons in spatially separated double-layer graphene nanoribbons

    International Nuclear Information System (INIS)

    Bagheri, Mehran; Bahrami, Mousa

    2014-01-01

    Motivated by innovative progresses in designing multi-layer graphene nanostructured materials in the laboratory, we theoretically investigate the Dirac plasmon modes of a spatially separated double-layer graphene nanoribbon system, made up of a vertically offset armchair and metallic graphene nanoribbon pair. We find striking features of the collective excitations in this novel Coulomb correlated system, where both nanoribbons are supposed to be either intrinsic (undoped/ungated) or extrinsic (doped/gated). In the former, it is shown the low-energy acoustical and the high-energy optical plasmon modes are tunable only by the inter-ribbon charge separation. In the later, the aforementioned plasmon branches are modified by the added doping factor. As a result, our model could be useful to examine the existence of a linear Landau-undamped low-energy acoustical plasmon mode tuned via the inter-ribbon charge separation as well as doping. This study might also be utilized for devising novel quantum optical waveguides based on the Coulomb coupled graphene nanoribbons

  15. Controlled power supply for isotopes separator

    International Nuclear Information System (INIS)

    Lavaitte, A.; Pottier, J.

    1953-01-01

    This equipment is destined to equip the separator of isotopes who is the subject of the CEA report n 138. It includes: - a controlled power supply in voltage. - a controlled power supply in current. The spectra of fluctuations of these assembly is different in the two cases. (authors) [fr

  16. Intelligent supervision control for the VASPS separator

    Energy Technology Data Exchange (ETDEWEB)

    Melo, A.V.; Mendes, J.R.P. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)], E-mail: jricardo@dep.fem.unicamp.br; Serapiao, A.B.S [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Rio Claro, SP (Brazil)

    2007-10-15

    The Vertical Annular Separation and Pumping System, VASPS, has been applied to low-pressure subsea wells with high gas production potential. In this system, the separation is carried out on the sea bed, thus allowing the monophase transmission through different pipelines. In the present work, an analysis has been established between two conceptually distinct models for the control system, which is under development and uses the Fuzzy Control technique for the Electrical Submersible Pump (ESP) speed selection. The contrast is held on the objective of each controller, placing the operational performance against the stability of the control signal, which leads to the exploration of many specific aspects of the system, its behavior and requirements. (author)

  17. The CEBAF Separator Cavity Resonance Control System

    CERN Document Server

    Wissmann, Mark J; Hovater, Curt; Plawski, Tomasz

    2005-01-01

    The CEBAF energy upgrade from 6 GeV to 12GeV will increase the range of beam energies available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three experimental halls. Consequently with the increase in RF separator cavity gradient needed for the higher energies, RF power will also increase requiring the cavities to have active resonance control. At the 6 GeV energy, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW), which is maintained at constant temperature of 95o Fahrenheit. This is no longer feasible and an active resonance control system, that controls both water temperature and flow has been built. The system uses a commercial PLC with embedded PID controls to control water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately closed loop control will be maintained by monit...

  18. Separation control with fluidic oscillators in water

    Science.gov (United States)

    Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

    2017-08-01

    The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

  19. The CEBAF separator cavity resonance control system

    International Nuclear Information System (INIS)

    M. Wissmann; C. Hovater; A. Guerra; T. Plawski

    2005-01-01

    The CEBAF energy upgrade will increase the maximum beam energy from 6 GeV to 12 GeV available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three halls. The resulting increase in RF separator cavity gradient and subsequent increase in RF power needed for these higher energies will require the cavities to have active resonance control. Currently, at the present 4 to 6 GeV energies, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW) which is maintained at a constant temperature of 95 Fahrenheit. This approach is no longer feasible and an active resonance control system that controls both water temperature and flow has been designed and built. The system uses a commercial PLC with embedded PID controls to regulate water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately, closed loop control will be maintained by monitoring each cavity's reflected power. This paper describes this system

  20. Electric currents couple spatially separated biogeochemical processes in marine sediment

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Risgaard-Petersen, Nils; Fossing, Henrik

    2010-01-01

    Some bacteria are capable of extracellular electron transfer, thereby enabling them to use electron acceptors and donors without direct cell contact 1, 2, 3, 4 . Beyond the micrometre scale, however, no firm evidence has previously existed that spatially segregated biogeochemical processes can...... be coupled by electric currents in nature. Here we provide evidence that electric currents running through defaunated sediment couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide and organic carbon deep within the sediment. Altering the oxygen concentration in the sea water...... in the sediment was driven by electrons conducted from the anoxic zone. A distinct pH peak in the oxic zone could be explained by electrochemical oxygen reduction, but not by any conventional sets of aerobic sediment processes. We suggest that the electric current was conducted by bacterial nanowires combined...

  1. Thermally-controlled centrifuge for isotopic separation

    International Nuclear Information System (INIS)

    Cenedese, A.; Cunsolo, D.

    1976-01-01

    Among the various methods proposed to obtain lighter component enrichment in the isotopic separation of uranium, ultracentrifugation is becoming more and more interesting today, as this process becomes a useful alternate method to gaseous diffusion. The ultracentrifuge main gas-dynamic features are investigated in the present study. In particular, the field inside the centrifuge has been subdivided into three axial zones: an internal central zone, characterized by an essentially axial flow; two external zones, near the two caps of the centrifuge; two intermediate zones, of a length of the order of the radius. For the analytical solution the linearized Navier-Stokes equations have been considered. The central zone flow is solved by separating the independent variables; the corresponding eigenvalue problem has been solved numerically. A series of eigensolutions which satisfy boundary conditions at the walls of the cylinder has been calculated. An integral method for the superimposition of the above mentioned eigensolutions is proposed in order to satisfy the conditions at the tops for thermally-controlled centrifuges. (author)

  2. Predicting speech release from masking through spatial separation in distance

    DEFF Research Database (Denmark)

    Chabot-Leclerc, Alexandre; Dau, Torsten

    2014-01-01

    of spatial release from masking (SRM) where the masker is moved, on-axis, away from the target. Two binaural models, which use the conventional audio signal-to-noise ratio (SNR) in the decision metric, and two monaural models, using a decision metric based on the SNR in the envelope domain (SNRenv), were...... considered. The predictions were compared to data from Westermann et al. [2013, POMA, 19, 050156] in condi- tions where the target was located 0.5 m in front of the listener and the masker was presented at a distance of 0.5, 2, 5 or 10 m in front of the listener. The data showed an SRM of 10 dB when moving...... the masker from a distance of 0.5 m to a distance of 10 m. The long-term monaural model based on the SNRenv metric was able to account for most of the SRM data, whereas the models that used the audio SNR did not predict any SRM, even when they included an equalizationcancellation-like process. The short...

  3. Phase separation in fluids exposed to spatially periodic external fields.

    Science.gov (United States)

    Vink, R L C; Archer, A J

    2012-03-01

    When a fluid is confined within a spatially periodic external field, the liquid-vapor transition is replaced by a different transition called laser-induced condensation (LIC) [Götze et al., Mol. Phys. 101, 1651 (2003)]. In d=3 dimensions, the periodic field induces an additional phase, characterized by large density modulations along the field direction. At the triple point, all three phases (modulated, vapor, and liquid) coexist. At temperatures slightly above the triple point and for low (high) values of the chemical potential, two-phase coexistence between the modulated phase and the vapor (liquid) is observed; by increasing the temperature further, both coexistence regions terminate in critical points. In this paper, we reconsider LIC using the Ising model to resolve a number of open issues. To be specific, we (1) determine the universality class of the LIC critical points and elucidate the nature of the correlations along the field direction, (2) present a mean-field analysis to show how the LIC phase diagram changes as a function of the field wavelength and amplitude, (3) develop a simulation method by which the extremely low tension of the interface between modulated and vapor or liquid phase can be measured, (4) present a finite-size scaling analysis to accurately extract the LIC triple point from finite-size simulation data, and (5) consider the fate of LIC in d=2 dimensions.

  4. Spatial control of groundwater contamination, using principal ...

    Indian Academy of Sciences (India)

    probe into the spatial controlling processes of groundwater contamination, using principal component analysis (PCA). ... topography, soil type, depth of water levels, and water usage. Thus, the ... of effective sites for infiltration of recharge water.

  5. Spatial control of groundwater contamination, using principal

    Indian Academy of Sciences (India)

    Spatial control of groundwater contamination, using principal component analysis ... anthropogenic (agricultural activities and domestic wastewaters), and marine ... The PC scores reflect the change of groundwater quality of geogenic origin ...

  6. Individual Differences in Spatial Pattern Separation Performance Associated with Healthy Aging in Humans

    Science.gov (United States)

    Stark, Shauna M.; Yassa, Michael A.; Stark, Craig E. L.

    2010-01-01

    Rodent studies have suggested that "pattern separation," the ability to distinguish among similar experiences, is diminished in a subset of aged rats. We extended these findings to the human using a task designed to assess spatial pattern separation behavior (determining at time of test whether pairs of pictures shown during the study were in the…

  7. Separation control of NACA0015 airfoil using plasma actuators

    Science.gov (United States)

    Harada, Daisuke; Sakakibara, Jun

    2017-11-01

    Separation control of NACA0015 airfoil by means of plasma actuators was investigated. Plasma actuators in spanwise intermittent layout on the suction surface of the airfoil were activated with spanwise phase difference φ = 0 or φ = π in the case of dimensionless burst frequencyF+ = 6 and F+ = 0.5 at Re = 6.3 ×104 . The lift and drag of the airfoil were measured using a two component force balance. The flow around the airfoil was measured by PIV analysis. In the condition of F+ = 6 and φ = π at around stall angle, which is 10 degrees, the lift-to-drag ratio was higher than that ofF+ = 6 and φ = 0 . Therefore, it was confirmed that aerodynamic characteristics of the airfoil improved by disturbances with temporal and spatial phase difference.

  8. Seafloor observations indicate spatial separation of coseismic and postseismic slips in the 2011 Tohoku earthquake

    Science.gov (United States)

    Iinuma, Takeshi; Hino, Ryota; Uchida, Naoki; Nakamura, Wataru; Kido, Motoyuki; Osada, Yukihito; Miura, Satoshi

    2016-01-01

    Large interplate earthquakes are often followed by postseismic slip that is considered to occur in areas surrounding the coseismic ruptures. Such spatial separation is expected from the difference in frictional and material properties in and around the faults. However, even though the 2011 Tohoku Earthquake ruptured a vast area on the plate interface, the estimation of high-resolution slip is usually difficult because of the lack of seafloor geodetic data. Here using the seafloor and terrestrial geodetic data, we investigated the postseismic slip to examine whether it was spatially separated with the coseismic slip by applying a comprehensive finite-element method model to subtract the viscoelastic components from the observed postseismic displacements. The high-resolution co- and postseismic slip distributions clarified the spatial separation, which also agreed with the activities of interplate and repeating earthquakes. These findings suggest that the conventional frictional property model is valid for the source region of gigantic earthquakes. PMID:27853138

  9. Separate Mechanisms Recruited by Exogenous and Endogenous Spatial Cues: Evidence from a Spatial Stroop Paradigm

    Science.gov (United States)

    Funes, Maria Jesus; Lupianez, Juan; Milliken, Bruce

    2007-01-01

    The present experiments tested whether endogenous and exogenous cues produce separate effects on target processing. In Experiment 1, participants discriminated whether an arrow presented left or right of fixation pointed to the left or right. For 1 group, the arrow was preceded by a peripheral noninformative cue. For the other group, the arrow was…

  10. Interaction mechanisms of cavitation bubbles induced by spatially and temporally separated fs-laser pulses.

    Directory of Open Access Journals (Sweden)

    Nadine Tinne

    Full Text Available The emerging use of femtosecond lasers with high repetition rates in the MHz regime together with limited scan speed implies possible mutual optical and dynamical interaction effects of the individual cutting spots. In order to get more insight into the dynamics a time-resolved photographic analysis of the interaction of cavitation bubbles is presented. Particularly, we investigated the influence of fs-laser pulses and their resulting bubble dynamics with various spatial as well as temporal separations. Different time courses of characteristic interaction effects between the cavitation bubbles were observed depending on pulse energy and spatio-temporal pulse separation. These ranged from merely no interaction to the phenomena of strong water jet formation. Afterwards, the mechanisms are discussed regarding their impact on the medical application of effective tissue cutting lateral to the laser beam direction with best possible axial precision: the mechanical forces of photodisruption as well as the occurring water jet should have low axial extend and a preferably lateral priority. Furthermore, the overall efficiency of energy conversion into controlled mechanical impact should be maximized compared to the transmitted pulse energy and unwanted long range mechanical side effects, e.g. shock waves, axial jet components. In conclusion, these experimental results are of great importance for the prospective optimization of the ophthalmic surgical process with high-repetition rate fs-lasers.

  11. Semiconductor nanoparticles with spatial separation of charge carriers: synthesis and optical properties

    International Nuclear Information System (INIS)

    Vasiliev, Roman B; Dirin, Dmitry N; Gaskov, Alexander M

    2011-01-01

    The results of studies on core/shell semiconductor nanoparticles with spatial separation of photoexcited charge carriers are analyzed and generalized. Peculiarities of the electronic properties of semiconductor/semiconductor heterojunctions formed inside such particles are considered. Data on the effect of spatial separation of charge carriers on the optical properties of nanoparticles including spectral shifts of the exciton bands, absorption coefficients and electron–hole pair recombination times are presented. Methods of synthesis of core/shell semiconductor nanoparticles in solutions are discussed. Specific features of the optical properties of anisotropic semiconductor nanoparticles with the semiconductor/semiconductor junctions are noted. The bibliography includes 165 references.

  12. The Economics of Storage, Transmission and Drought: Integrating Variable Wind Power into Spatially Separated Electricity Grids

    NARCIS (Netherlands)

    Scora, H.; Sopinka, A.; Kooten, van G.C.

    2012-01-01

    To mitigate the high variability of wind and make it a more viable renewable energy source, observers recommend greater integration of spatially-separated electrical grids, with high transmission lines linking load centers, scattered wind farms and hydro storage sites. In this study, we examine the

  13. Multi-Antenna Data Collector for Smart Metering Networks with Integrated Source Separation by Spatial Filtering

    Science.gov (United States)

    Quednau, Philipp; Trommer, Ralph; Schmidt, Lorenz-Peter

    2016-03-01

    Wireless transmission systems in smart metering networks share the advantage of lower installation costs due to the expandability of separate infrastructure but suffer from transmission problems. In this paper the issue of interference of wireless transmitted smart meter data with third party systems and data from other meters is investigated and an approach for solving the problem is presented. A multi-channel wireless m-bus receiver was developed to separate the desired data from unwanted interferers by spatial filtering. The according algorithms are presented and the influence of different antenna types on the spatial filtering is investigated. The performance of the spatial filtering is evaluated by extensive measurements in a realistic surrounding with several hundreds of active wireless m-bus transponders. These measurements correspond to the future environment for data-collectors as they took place in rural and urban areas with smart gas meters equipped with wireless m-bus transponders installed in almost all surrounding buildings.

  14. Ultrafast Dynamics in Vanadium Dioxide: Separating Spatially Segregated Mixed Phase Dynamics in the Time-domain

    Science.gov (United States)

    Hilton, David

    2011-10-01

    In correlated electronic systems, observed electronic and structural behavior results from the complex interplay between multiple, sometimes competing degrees-of- freedom. One such material used to study insulator-to-metal transitions is vanadium dioxide, which undergoes a phase transition from a monoclinic-insulating phase to a rutile-metallic phase when the sample is heated to 340 K. The major open question with this material is the relative influence of this structural phase transition (Peirels transition) and the effects of electronic correlations (Mott transition) on the observed insulator-to-metal transition. Answers to these major questions are complicated by vanadium dioxide's sensitivity to perturbations in the chemical structure in VO2. For example, related VxOy oxides with nearly a 2:1 ratio do not demonstrate the insulator-to- metal transition, while recent work has demonstrated that W:VO2 has demonstrated a tunable transition temperature controllable with tungsten doping. All of these preexisting results suggest that the observed electronic properties are exquisitely sensitive to the sample disorder. Using ultrafast spectroscopic techniques, it is now possible to impulsively excite this transition and investigate the photoinduced counterpart to this thermal phase transition in a strongly nonequilibrium regime. I will discuss our recent results studying the terahertz-frequency conductivity dynamics of this photoinduced phase transition in the poorly understood near threshold temperature range. We find a dramatic softening of the transition near the critical temperature, which results primarily from the mixed phase coexistence near the transition temperature. To directly study this mixed phase behavior, we directly study the nucleation and growth rates of the metallic phase in the parent insulator using non-degenerate optical pump-probe spectroscopy. These experiments measure, in the time- domain, the coexistent phase separation in VO2 (spatially

  15. Spatial xenon oscillation control with expert systems

    International Nuclear Information System (INIS)

    Alten, S.; Danofsky, R.A.

    1993-01-01

    Spatial power oscillations were attributed to the xenon transients in a reactor core in 1958 by Randall and St. John. These transients are usually initiated by a local reactivity insertion and lead to divergent axial flux oscillations in the core at constant power. Several heuristic manual control strategies and automatic control methods were developed to damp the xenon oscillations at constant power operations. However, after the load-follow operation of the reactors became a necessity of life, a need for better control strategies arose. Even though various advanced control strategies were applied to solve the xenon oscillation control problem for the load-follow operation, the complexity of the system created difficulties in modeling. The strong nonlinearity of the problem requires highly sophisticated analytical approaches that are quite inept for numerical solutions. On the other hand, the complexity of a system and heuristic nature of the solutions are the basic reasons for using artificial intelligence techniques such as expert systems

  16. Investigation and Comparison of Separate Meter-In Separate Meter-Out Control Strategies

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Skoubo, Tobias

    2014-01-01

    In the later years, there has been an increased focus on new valve types, which yield the possibility to do Separate Meter-In Separate Meter-Out (SMISMO) control. This includes both digital valves, but proportional valves with separate metering spools and build in pressure sensors are also emerging....... The possibility to independently control the meter-in and meter-out side not only increase the functionality of the system, but also opens up for better performance and/or lowered energy consumption. The focus of the current paper is therefore on investigation and comparison of what may be obtained using...

  17. Full Duplex Emulation via Spatial Separation of Half Duplex Nodes in a Planar Cellular Network

    DEFF Research Database (Denmark)

    Thomsen, Henning; Kim, Dong Min; Popovski, Petar

    2016-01-01

    A Full Duplex Base Station (FD-BS) can be used to serve simultaneously two Half-Duplex (HD) Mobile Stations (MSs), one working in the uplink and one in the downlink, respectively. The same functionality can be realized by having two interconnected and spatially separated Half Duplex Base Stations...... (HD-BSs), which is a scheme termed CoMPflex (CoMP for In-Band Wireless Full Duplex). A FD-BS can be seen as a special case of CoMPflex with separation distance zero. In this paper we study the performance of CoMPflex in a two-dimensional cellular scenario using stochastic geometry and compare...

  18. Deterministic Generation of Quantum State Transfer Between Spatially Separated Single Molecule Magnets

    International Nuclear Information System (INIS)

    Song Peijun; Lue Xinyou; Huang Pei; Hao Xiangying; Yang Xiaoxue

    2010-01-01

    We propose a new scheme for realizing deterministic quantum state transfer (QST) between two spatially separated single molecule magnets (SMMs) with the framework of cavity quantum electrodynamics (QED). In the present scheme, two SMMs are trapped in two spatially separated optical cavities coupled by an optical fiber. Through strictly numerically simulating, we demonstrate that our scheme is robust with respect to the SMMs' spontaneous decay and fiber loss under the conditions of dispersive SMMs-field interaction and strong coupling of cavity fiber. In addition, we also discuss the influence of photon leakage out of cavities and show that our proposal is good enough to demonstrate the generation of QST with high fidelity utilizing the current experimental technology. The present investigation provides research opportunities for realizing QST between solid-state qubits and may result in a substantial impact on the progress of solid-state-based quantum communications network. (general)

  19. Airfoil boundary layer separation and control at low Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Yarusevych, S.; Sullivan, P.E. [University of Toronto, Department of Mechanical and Industrial Engineering, Toronto, ON (Canada); Kawall, J.G. [Ryerson University, Department of Mechanical and Industrial Engineering, Toronto, ON (Canada)

    2005-04-01

    The boundary layer separation on a NACA 0025 airfoil was studied experimentally via hot-wire anemometry and surface pressure measurements. The results provide added insight into periodic boundary layer control, suggesting that matching the excitation frequency with the most amplified disturbance in the separated shear layer is optimal for improving airfoil performance. (orig.)

  20. Who plans for health improvement? SEA, HIA and the separation of spatial planning and health planning

    International Nuclear Information System (INIS)

    Bond, Alan; Cave, Ben; Ballantyne, Rob

    2013-01-01

    This study examines whether there is active planning for health improvement in the English spatial planning system and how this varies across two regions using a combination of telephone surveys and focus group interviews in 2005 and 2010. The spatial planning profession was found to be ill-equipped to consider the health and well-being implications of its actions, whilst health professionals are rarely engaged and have limited understanding and aspirations when it comes to influencing spatial planning. Strategic Environmental Assessment was not considered to be successful in integrating health into spatial plans, given it was the responsibility of planners lacking the capacity to do so. For their part, health professionals have insufficient knowledge and understanding of planning and how to engage with it to be able to plan for health gains rather than simply respond to health impacts. HIA practice is patchy and generally undertaken by health professionals outside the statutory planning framework. Thus, whilst appropriate assessment tools exist, they currently lack a coherent context within which they can function effectively and the implementation of the Kiev protocol requiring the engagement of health professionals in SEA is not to likely improve the consideration of health in planning while there continues to be separation of functions between professions and lack of understanding of the other profession. -- Highlights: ► Health professionals have limited aspirations for health improvement through the planning system. ► Spatial planners are ill-equipped to understand the health and well-being implications of their activities. ► SEA and HIA currently do not embed health consideration in planning decisions. ► The separation of health and planning functions is problematic for the effective conduct of SEA and/or HIA

  1. Who plans for health improvement? SEA, HIA and the separation of spatial planning and health planning

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Alan, E-mail: alan.bond@uea.ac.uk [InteREAM (Interdisciplinary Research in Environmental Assessment and Management), School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ (United Kingdom); Cave, Ben, E-mail: ben.cave@bcahealth.co.uk [Ben Cave Associates Ltd., Leeds (United Kingdom); Ballantyne, Rob, E-mail: robdballantyne@gmail.com [Planning and Health Consultant, Oxfordshire (United Kingdom)

    2013-09-15

    This study examines whether there is active planning for health improvement in the English spatial planning system and how this varies across two regions using a combination of telephone surveys and focus group interviews in 2005 and 2010. The spatial planning profession was found to be ill-equipped to consider the health and well-being implications of its actions, whilst health professionals are rarely engaged and have limited understanding and aspirations when it comes to influencing spatial planning. Strategic Environmental Assessment was not considered to be successful in integrating health into spatial plans, given it was the responsibility of planners lacking the capacity to do so. For their part, health professionals have insufficient knowledge and understanding of planning and how to engage with it to be able to plan for health gains rather than simply respond to health impacts. HIA practice is patchy and generally undertaken by health professionals outside the statutory planning framework. Thus, whilst appropriate assessment tools exist, they currently lack a coherent context within which they can function effectively and the implementation of the Kiev protocol requiring the engagement of health professionals in SEA is not to likely improve the consideration of health in planning while there continues to be separation of functions between professions and lack of understanding of the other profession. -- Highlights: ► Health professionals have limited aspirations for health improvement through the planning system. ► Spatial planners are ill-equipped to understand the health and well-being implications of their activities. ► SEA and HIA currently do not embed health consideration in planning decisions. ► The separation of health and planning functions is problematic for the effective conduct of SEA and/or HIA.

  2. Management of Vortices Trailing Flapped Wings via Separation Control

    Science.gov (United States)

    Greenblatt, David

    2005-01-01

    A pilot study was conducted on a flapped semi-span model to investigate the concept and viability of near-wake vortex management via separation control. Passive control was achieved by means of a simple fairing and active control was achieved via zero mass-flux blowing slots. Vortex sheet strength, estimated by integrating surface pressure ports, was used to predict vortex characteristics by means of inviscid rollup relations. Furthermore, vortices trailing the flaps were mapped using a seven-hole probe. Separation control was found to have a marked effect on vortex location, strength, tangential velocity, axial velocity and size over a wide range of angles of attack and control conditions. In general, the vortex trends were well predicted by the inviscid rollup relations. Manipulation of the separated flow near the flap edges exerted significant control over both outboard and inboard edge vortices while producing negligible lift excursions. Dynamic separation and attachment control was found to be an effective means for dynamically perturbing the vortex from arbitrarily long wavelengths down to wavelengths less than a typical wingspan. In summary, separation control has the potential for application to time-independent or time-dependent wake alleviation schemes, where the latter can be deployed to minimize adverse effects on ride-quality and dynamic structural loading.

  3. Application of THz probe radiation in low-coherent tomographs based on spatially separated counterpropagating beams

    Energy Technology Data Exchange (ETDEWEB)

    Kuritsyn, I I; Shkurinov, A P; Nazarov, M M [Department of Physics, M.V. Lomonosov Moscow State University (Russian Federation); Mandrosov, V I [Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow Region (Russian Federation); Cherkasova, O P [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2013-10-31

    A principle of designing a high-resolution low-coherent THz tomograph, which makes it possible to investigate media with a high spatial resolution (in the range λ{sub 0} – 2λ{sub 0}, where λ{sub 0} is the average probe wavelength) is considered. The operation principle of this tomograph implies probing a medium by radiation with a coherence length of 8λ{sub 0} and recording a hologram of a focused image of a fixed layer of this medium using spatially separated counterpropagating object and reference beams. Tomograms of the medium studied are calculated using a temporal approach based on application of the time correlation function of probe radiation. (terahertz radiation)

  4. Gift exchange and the separation of ownership and control

    NARCIS (Netherlands)

    Maximiano, S.; Sloof, R.; Sonnemans, J.

    2006-01-01

    Numerous gift exchange experiments have found a positive relationship between employers' wage offers and workers' effort levels. In (almost) all these experiments the employer both owns and controls the firm. Yet in reality many firms are characterized by the separation of ownership and control. In

  5. Blind Separation of Nonstationary Sources Based on Spatial Time-Frequency Distributions

    Directory of Open Access Journals (Sweden)

    Zhang Yimin

    2006-01-01

    Full Text Available Blind source separation (BSS based on spatial time-frequency distributions (STFDs provides improved performance over blind source separation methods based on second-order statistics, when dealing with signals that are localized in the time-frequency (t-f domain. In this paper, we propose the use of STFD matrices for both whitening and recovery of the mixing matrix, which are two stages commonly required in many BSS methods, to provide robust BSS performance to noise. In addition, a simple method is proposed to select the auto- and cross-term regions of time-frequency distribution (TFD. To further improve the BSS performance, t-f grouping techniques are introduced to reduce the number of signals under consideration, and to allow the receiver array to separate more sources than the number of array sensors, provided that the sources have disjoint t-f signatures. With the use of one or more techniques proposed in this paper, improved performance of blind separation of nonstationary signals can be achieved.

  6. Concentration control in an isotope separation plant; Regulation des concentrations dans une usine de separation isotopique

    Energy Technology Data Exchange (ETDEWEB)

    Jacques, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    Concentration control is examined for the case of a gaseous diffusion plant for uranium isotope separation. The effects of various typical perturbations are described and adequate systems of corrective actions are determined according to selected criteria. (author) [French] On considere une installation de separation des isotopes de l'uranium par diffusion gazeuse. On etudie les effets sur les concentrations isotopiques de diverses perturbations type donnees a l'avance et on determine le systeme d'actions correctives qui permet de reduire ces effets d'apres un critere d'efficacite donne. (auteur)

  7. Control of spatial discretisation in coastal oil spill modelling

    OpenAIRE

    Li, Yang

    2007-01-01

    Spatial discretisation plays an important role in many numerical environmental models. This paper studies the control of spatial discretisation in coastal oil spill modelling with a view to assure the quality of modelling outputs for given spatial data inputs. Spatial data analysis techniques are effective for investigating and improving the spatial discretisation in different phases of the modelling. Proposed methods are implemented and tested with experimental models. A new “Automatic Searc...

  8. Spatial separation and bidirectional trafficking of proteins using a multi-functional reporter

    Directory of Open Access Journals (Sweden)

    Klaubert Dieter H

    2008-04-01

    Full Text Available Abstract Background The ability to specifically label proteins within living cells can provide information about their dynamics and function. To study a membrane protein, we fused a multi-functional reporter protein, HaloTag®, to the extracellular domain of a truncated integrin. Results Using the HaloTag technology, we could study the localization, trafficking and processing of an integrin-HaloTag fusion, which we showed had cellular dynamics consistent with native integrins. By labeling live cells with different fluorescent impermeable and permeable ligands, we showed spatial separation of plasma membrane and internal pools of the integrin-HaloTag fusion, and followed these protein pools over time to study bi-directional trafficking. In addition to combining the HaloTag reporter protein with different fluorophores, we also employed an affinity tag to achieve cell capture. Conclusion The HaloTag technology was used successfully to study expression, trafficking, spatial separation and real-time translocation of an integrin-HaloTag fusion, thereby demonstrating that this technology can be a powerful tool to investigate membrane protein biology in live cells.

  9. A PC based control system for the CERN ISOLDE separators

    International Nuclear Information System (INIS)

    Billinge, R.; Bret, A.; Deloose, I.; Pace, A.; Shering, G.

    1992-01-01

    The control system of the two isotope separators of CERN, named ISOLDE, is being completely redesigned with the goal of having a flexible, high performance and inexpensive system. A new architecture that makes heavy use of the commercial software and hardware available for the huge Personal Computer (PC) market is being implemented on the 1700 geographically distributed control channels of the separators. 8 MS-DOS TM i386-based PCs with about 80 acquisition/control boards are used to access the equipments while 3 other PCs running Microsoft Windows TM and Microsoft Excel TM are used as consoles, the whole through a Novell TM Local Area Network with a PC Disk Server used as a database. This paper describes the interesting solutions found and discusses the reduced programming work load and costs that are expected to build the system before the start of the separators in March 1992. (author)

  10. International Conference on Instability and Control of Massively Separated Flows

    CERN Document Server

    Soria, Julio

    2015-01-01

    This book contains the outcome of the international meeting on instability, control and noise generated by massive flow separation that was organized at the Monash Center, in Prato, Italy, September 4-6, 2013. The meeting served as the final review of the EU-FP7 Instability and Control of Massively Separated Flows Marie Curie travel grant and was supported by the European Office of Aerospace Research and Development. Fifty leading specialists from twelve countries reviewed the progress made since the 50s of the last century and discussed modern analysis techniques, advanced experimental flow diagnostics, and recent developments in active flow control techniques from the incompressible to the hypersonic regime. Applications involving massive flow separation and associated instability and noise generation mechanisms of interest to the aeronautical, naval and automotive industries have been addressed from a theoretical, numerical or experimental point of view, making this book a unique source containing the stat...

  11. Impact of neighborhood separation on the spatial reciprocity in the prisoner’s dilemma game

    International Nuclear Information System (INIS)

    Xia, Chengyi; Miao, Qin; Zhang, Juanjuan

    2013-01-01

    Highlights: • We present a novel game model in which interaction and learning neighborhood is not identical. • The separation between interaction and learning neighborhood can largely influence the cooperative behaviors. • Monte Carlo simulations are utilized to verify the evolution of cooperation. • When IN is fixed to be 4, medium-sized LN = 8 is the optimal size to promote the cooperation. • When LN is fixed to be 4, the cooperation can also be highly enhanced when IN > 4. -- Abstract: The evolutionary game theory is a very powerful tool to understand the collective cooperation behavior in many real-world systems. In the spatial game model, the payoff is often first obtained within a specific neighborhood (i.e., interaction neighborhood) and then the focal player imitates or learns the behavior of a randomly selected one inside another neighborhood which is named after the learning neighborhood. However, most studies often assume that the interaction neighborhood is identical with the learning neighborhood. Beyond this assumption, we present a spatial prisoner’s dilemma game model to discuss the impact of separation between interaction neighborhood and learning neighborhood on the cooperative behaviors among players on the square lattice. Extensive numerical simulations demonstrate that separating the interaction neighborhood from the learning neighborhood can dramatically affect the density of cooperators (ρ C ) in the population at the stationary state. In particular, compared to the standard case, we find that the medium-sized learning (interaction) neighborhood allows the cooperators to thrive and substantially favors the evolution of cooperation and ρ C can be greatly elevated when the interaction (learning) neighborhood is fixed, that is, too little or much information is not beneficial for players to make the contributions for the collective cooperation. Current results are conducive to further analyzing and understanding the emergence of

  12. Spatially resolved micro-Raman observation on the phase separation of effloresced sea salt droplets.

    Science.gov (United States)

    Xiao, Han-Shuang; Dong, Jin-Ling; Wang, Liang-Yu; Zhao, Li-Jun; Wang, Feng; Zhang, Yun-Hong

    2008-12-01

    We report on the investigation of the phase separation of individual seawater droplets in the efflorescence processes with the spatially resolved Raman system. Upon decreasing the relative humidity (RH), CaSO4.0.5H2O separated out foremost fromthe droplet atan unexpectedly high RH of approcimately 90%. Occasionally, CaSO4.2H2O substituted for CaSO4.O.5H2O crystallizing first at approximately 78% RH. Relatively large NaCI solids followed to crystallize at approximately 55% RH and led to the great loss of the solution. Then, the KMgCl3.6H2O crystallites separated out from the residual solutions, adjacentto NaCl at approximately 44% RH. Moreover, a shell structure of dried sea salt particle was found to form at low RHs, with the NaCl crystals in the core and minor supersaturated solutions covered with MgSO4 gel coating on the surface. Ultimately, the shielded solution partly effloresced into MgSO4 hydrates at very dry state (<5% RH).

  13. Active Control of Flow Separation Over an Airfoil

    Science.gov (United States)

    Ravindran, S. S.

    1999-01-01

    Designing an aircraft without conventional control surfaces is of interest to aerospace community. In this direction, smart actuator devices such as synthetic jets have been proposed to provide aircraft maneuverability instead of control surfaces. In this article, a numerical study is performed to investigate the effects of unsteady suction and blowing on airfoils. The unsteady suction and blowing is introduced at the leading edge of the airfoil in the form of tangential jet. Numerical solutions are obtained using Reynolds-Averaged viscous compressible Navier-Stokes equations. Unsteady suction and blowing is investigated as a means of separation control to obtain lift on airfoils. The effect of blowing coefficients on lift and drag is investigated. The numerical simulations are compared with experiments from the Tel-Aviv University (TAU). These results indicate that unsteady suction and blowing can be used as a means of separation control to generate lift on airfoils.

  14. Fluid Mechanics of Wing Adaptation for Separation Control

    Science.gov (United States)

    Chandrasekhara, M. S.; Wilder, M. C.; Carr, L. W.; Davis, Sanford S. (Technical Monitor)

    1997-01-01

    The unsteady fluid mechanics associated with use of a dynamically deforming leading edge airfoil for achieving compressible flow separation control has been experimentally studied. Changing the leading edge curvature at rapid rates dramatically alters the flow vorticity dynamics which is responsible for the many effects observed in the flow.

  15. Control strategies for laser separation of carbon isotopes

    Indian Academy of Sciences (India)

    Unknown

    Control strategies for laser separation of carbon isotopes. V PARTHASARATHY*, A K ... The emerging market for medical applications of C-13 is projected to be in the range of hundreds of ..... thermal effects during irradiation. In the absence of ...

  16. Turbulent Flow Modification With Thermoacoustic Waves for Separation Control

    Science.gov (United States)

    2017-08-24

    respectively. At the outlet, the time-average flow is set to be the target state of the sponge zone. In this section, the effects of momentum thickness...Turbulent Flow Modification With Thermoacoustic Waves For Separation Control The views, opinions and/or findings contained in this report are those...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. Florida State University Sponsored Research Administration 874

  17. Coupling effects of grey-grey separate spatial screening soliton pairs

    International Nuclear Information System (INIS)

    Jiang Qichang; Su Yanli; Ji Xuanmang

    2012-01-01

    The existence and coupling effects of grey-grey separate spatial soliton pairs in a biased series non-photovoltaic photorefractive crystal circuit are investigated in this paper. The numerical solution of grey-grey soliton pairs is derived. The coupling effects between two grey solitons resulting from the input optical intensity and crystal temperature are analyzed numerically. The results show that when the input optical intensity of one crystal changes, two grey solitons in a soliton pair will all change; that is, two grey solitons can affect each other by the light-induced current that flows from one crystal to another. When the temperature of one crystal increases, the intensity width of the grey soliton in this crystal first decreases and then increases. Simultaneously, the intensity width of another grey soliton increases monotonically.

  18. Generation of dynamo waves by spatially separated sources in the Earth and other celestial bodies

    Science.gov (United States)

    Popova, E.

    2017-12-01

    The amplitude and the spatial configuration of the planetary and stellar magnetic field can changing over the years. Celestial bodies can have cyclic, chaotic or unchanging in time magnetic activity which is connected with a dynamo mechanism. This mechanism is based on the consideration of the joint influence of the alpha-effect and differential rotation. Dynamo sources can be located at different depths (active layers) of the celestial body and can have different intensities. Application of this concept allows us to get different forms of solutions and some of which can include wave propagating inside the celestial body. We analytically showed that in the case of spatially separated sources of magnetic field each source generates a wave whose frequency depends on the physical parameters of its source. We estimated parameters of sources required for the generation nondecaying waves. We discus structure of such sources and matter motion (including meridional circulation) in the liquid outer core of the Earth and active layers of other celestial bodies.

  19. Using Pitch, Amplitude Modulation, and Spatial Cues for Separation of Harmonic Instruments from Stereo Music Recordings

    Directory of Open Access Journals (Sweden)

    Bryan Pardo

    2007-01-01

    Full Text Available Recent work in blind source separation applied to anechoic mixtures of speech allows for improved reconstruction of sources that rarely overlap in a time-frequency representation. While the assumption that speech mixtures do not overlap significantly in time-frequency is reasonable, music mixtures rarely meet this constraint, requiring new approaches. We introduce a method that uses spatial cues from anechoic, stereo music recordings and assumptions regarding the structure of musical source signals to effectively separate mixtures of tonal music. We discuss existing techniques to create partial source signal estimates from regions of the mixture where source signals do not overlap significantly. We use these partial signals within a new demixing framework, in which we estimate harmonic masks for each source, allowing the determination of the number of active sources in important time-frequency frames of the mixture. We then propose a method for distributing energy from time-frequency frames of the mixture to multiple source signals. This allows dealing with mixtures that contain time-frequency frames in which multiple harmonic sources are active without requiring knowledge of source characteristics.

  20. The effect of fire on spatial separation between wolves and caribou

    Directory of Open Access Journals (Sweden)

    Hugh S. Robinson

    2012-03-01

    Full Text Available Fire management is an important conservation tool in Canada’s national parks. Fires can benefit some species, while others may be negatively impacted. We used GPS and VHF collar data for 47 wolves from 12 separate packs and 153 caribou from 5 separate herds, and resource selection analysis to model the effects of fire on these species’ habitat and potential interactions. Resource selection modeling showed that wolves select for burned areas and areas close to burns, presumably due to the presence of primary prey (i.e., elk and moose, while caribou avoid burns. Fire reduced the amount of high quality caribou habitat (a direct effect, but also increased the probability of wolf-caribou overlap (an indirect effect. We delineated a spatial index of caribou “safe zones” (areas of low overlap with wolves, and found a positive relationship between the proportion of a herd’s home range represented by “safe zone” in winter and population size (P = 0.10, n=4. While currently-planned prescribed fires in Banff and Jasper reduced the amount of quality caribou habitat by up to 4%, they reduced the area of “safe zones” by up to 7%, varying by herd, location, and season. We suggest that conservation managers should account for the indirect, predator-mediated impacts of fire on caribou in addition to direct effects of habitat loss.

  1. Transient performance of integrated SOFC system including spatial temperature control

    OpenAIRE

    Mueller, F; Fardadi, M; Shaffer, B; Brouwer, J; Jabbari, F

    2010-01-01

    Spatial temperature feedback control has been developed for a simulated integrated non-pressurized simple cycle solid oxide fuel cell (SOFC) system. The fuel cell spatial temperature feedback controller is based on (1) feed-forward set-points that minimize temperature variation in the fuel cell electrode-electrolyte solid temperature profile for the system operating power range, and (2) decentralized proportional-integral based feedback to maintain the fuel cell spatial temperature profile du...

  2. Method and apparatus for controlled condensation isotope separation

    International Nuclear Information System (INIS)

    Sullivan, J.A.; Lee, J.T. Jr.; Kim, K.C.

    1981-01-01

    The invention provides a method for producing controlled homogeneous condensation of a molecular feed gas containing several isotopes. The feed gas flows at supersonic rates through an expansion nozzle under conditions at which the gas would normally condense. The gas is irradiated with laser radiation of a wavelength that selectively excites those molecules in the feed gas that contain a particular isotope, thus preventing their condensation. Condensate particles may be aerodynamically separated from the flowing gas stream

  3. Aspects regarding computer control of 15 N separation plant

    International Nuclear Information System (INIS)

    Kaucsar, M.; Cosma, V.; Axente, D.; Baldea, A.; Bendea, H.; Bunea, V

    2001-01-01

    In order to improve the efficiency of a separation plant the whole process must be automatically controlled. The plant has a single output - the isotopic product. This output is characterized by a complex function, which involves qualitative or/and quantitative properties of the product. There are two important inputs into the system, namely: the amount of the substances and compounds which supply the plant and the electric power consumption. Our first aim is to reduce the input/output ratio of the separation plant. On the other hand, by applying this automatic control system we can reduce the operating personnel also. The isotopic product is sampled and analyzed using a dedicated mass spectrometer. An overall closed loop through the separation plant including this mass spectrometer could be very efficient, but the theoretical analysis is too complex and it is very difficult to realize it in practice. Therefore, multiple local control loops are preferred to apply for each product correlated parameter. Between these parameters there are complex interdependencies, governed by differential equations. The computer is equipped with standard input/output hardware, but in order to use it in the complex feedback loops, extra input/output hardware must be added, namely, dedicated input/output module cards. Depending on the operating principle of the detectors and actuators the signals involved in the whole system are analog and digital. The majority of the sensors and transducers generates analog signals and only a few of them have digital output. The last case is typical for transducers specialized mainly for detecting the level of a parameter. Actuators also need analog or digital control signals, corresponding to their operating principles. The computer control of isotopic plant has a great advantage of being very flexible in implementing adequate control software with operator friendly interfacing routines. (authors)

  4. Suspension Bridge Flutter for Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, T.; Thoft-Christensen, Palle

    Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

  5. Chemistry with spatial control using particles and streams†

    Science.gov (United States)

    Kalinin, Yevgeniy V.; Murali, Adithya

    2012-01-01

    Spatial control of chemical reactions, with micro- and nanometer scale resolution, has important consequences for one pot synthesis, engineering complex reactions, developmental biology, cellular biochemistry and emergent behavior. We review synthetic methods to engineer this spatial control using chemical diffusion from spherical particles, shells and polyhedra. We discuss systems that enable both isotropic and anisotropic chemical release from isolated and arrayed particles to create inhomogeneous and spatially patterned chemical fields. In addition to such finite chemical sources, we also discuss spatial control enabled with laminar flow in 2D and 3D microfluidic networks. Throughout the paper, we highlight applications of spatially controlled chemistry in chemical kinetics, reaction-diffusion systems, chemotaxis and morphogenesis. PMID:23145348

  6. Controls on the spatial distribution of oceanic δ13CDIC

    Directory of Open Access Journals (Sweden)

    P. B. Holden

    2013-03-01

    Full Text Available We describe the design and evaluation of a large ensemble of coupled climate–carbon cycle simulations with the Earth system model of intermediate complexity GENIE. This ensemble has been designed for application to a range of carbon cycle questions, including the causes of late-Quaternary fluctuations in atmospheric CO2. Here we evaluate the ensemble by applying it to a transient experiment over the recent industrial era (1858 to 2008 AD. We employ singular vector decomposition and principal component emulation to investigate the spatial modes of ensemble variability of oceanic dissolved inorganic carbon (DIC δ13C, considering both the spun-up pre-industrial state and the transient change. These analyses allow us to separate the natural (pre-industrial and anthropogenic controls on the δ13CDIC distribution. We apply the same dimensionally-reduced emulation techniques to consider the drivers of the spatial uncertainty in anthropogenic DIC. We show that the sources of uncertainty related to the uptake of anthropogenic δ13CDIC and DIC are quite distinct. Uncertainty in anthropogenic δ13C uptake is controlled by air–sea gas exchange, which explains 63% of modelled variance. This mode of variability is largely absent from the ensemble variability in CO2 uptake, which is rather driven by uncertainties in thermocline ventilation rates. Although the need to account for air–sea gas exchange is well known, these results suggest that, to leading order, uncertainties in the ocean uptake of anthropogenic 13C and CO2 are governed by very different processes. This illustrates the difficulties in reconstructing one from the other, and furthermore highlights the need for careful targeting of both δ13CDIC and DIC observations to better constrain the ocean sink of anthropogenic CO2.

  7. Separate first- and second-order processing is supported by spatial summation estimates at the fovea and eccentrically.

    Science.gov (United States)

    Sukumar, Subash; Waugh, Sarah J

    2007-03-01

    We estimated spatial summation areas for the detection of luminance-modulated (LM) and contrast-modulated (CM) blobs at the fovea, 2.5, 5 and 10 deg eccentrically. Gaussian profiles were added or multiplied to binary white noise to create LM and CM blob stimuli and these were used to psychophysically estimate detection thresholds and spatial summation areas. The results reveal significantly larger summation areas for detecting CM than LM blobs across eccentricity. These differences are comparable to receptive field size estimates made in V1 and V2. They support the notion that separate spatial processing occurs for the detection of LM and CM stimuli.

  8. Spectrometer Baseline Control Via Spatial Filtering

    Science.gov (United States)

    Burleigh, M. R.; Richey, C. R.; Rinehart, S. A.; Quijada, M. A.; Wollack, E. J.

    2016-01-01

    An absorptive half-moon aperture mask is experimentally explored as a broad-bandwidth means of eliminating spurious spectral features arising from reprocessed radiation in an infrared Fourier transform spectrometer. In the presence of the spatial filter, an order of magnitude improvement in the fidelity of the spectrometer baseline is observed. The method is readily accommodated within the context of commonly employed instrument configurations and leads to a factor of two reduction in optical throughput. A detailed discussion of the underlying mechanism and limitations of the method are provided.

  9. On spatial spillover in feedforward and feedback noise control

    Science.gov (United States)

    Xie, Antai; Bernstein, Dennis

    2017-03-01

    Active feedback noise control for rejecting broadband disturbances must contend with the Bode integral constraint, which implies that suppression over some frequency range gives rise to amplification over another range at the performance microphone. This is called spectral spillover. The present paper deals with spatial spillover, which refers to the amplification of noise at locations where no microphone is located. A spatial spillover function is defined, which is valid for both feedforward and feedback control with scalar and vector control inputs. This function is numerically analyzed and measured experimentally. Obstructions are introduced in the acoustic space to investigate their effect on spatial spillover.

  10. Investigation of Separate Meter-In Separate Meter-Out Control Strategies for Systems with Over Centre Valves

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Hansen, Rico Hjerm

    2010-01-01

    to overcome this problem, but it typically implies higher energy consumption and/or decreased control performance. With the development of robust sensors and new valve types with separate meter-in, separate meter-out control it is, however, possible to overcome these stability problems in a much more...... intelligent way, also adding increased functionality to the system. The focus of the current paper is therefore on investigation of different control strategies for Separate Meter-In Separate Meter-Out (SMISMO) control of general single axis hydraulic system with a differential cylinder and an over......-centre valve included. The paper first presents a general model of the system considered, which is experimentally verified. This is followed by a discussion of different control strategies and their implications. For each of the control strategies controllers are described, taking into account the dynamics...

  11. Transitory Control of Unsteady Separation using Pulsed Actuation

    International Nuclear Information System (INIS)

    Woo, George T K; Glezer, Ari

    2011-01-01

    The dynamic mechanisms of transitory flow attachment effected by pulsed actuation of the separated flow over a stalled airfoil are investigated experimentally. Actuation is effected by momentary pulsed jets generated by a spanwise array of combustion-based actuators such that the characteristic time of jet duration is nominally an order of magnitude shorter than the flow's convective time scale. The transitory flow field in the cross stream plane above the airfoil and in its near wake is investigated using multiple high-resolution PIV images that are obtained phase-locked to the actuation for continuous tracking of vorticity concentrations. The brief actuation pulse leads to severing of the separated vorticity layer and the subsequent shedding of large-scale vortical structures owing to the collapse of the separated flow domain which is accompanied by strong changes in the circulation about the entire airfoil. By exploiting the disparity between the characteristic times of flow response to actuation and relaxation, it is shown that successive actuation pulses can extend the flow attachment and enhance the global aerodynamic performance. It is also shown that coupling of the actuation to the airfoil's motion during cyclical pitch enhances the effect of transitory flow control and leads to a significant suppression of dynamic stall.

  12. Visual Spatial Attention Training Improve Spatial Attention and Motor Control for Unilateral Neglect Patients.

    Science.gov (United States)

    Wang, Wei; Ji, Xiangtong; Ni, Jun; Ye, Qian; Zhang, Sicong; Chen, Wenli; Bian, Rong; Yu, Cui; Zhang, Wenting; Shen, Guangyu; Machado, Sergio; Yuan, Tifei; Shan, Chunlei

    2015-01-01

    To compare the effect of visual spatial training on the spatial attention to that on motor control and to correlate the improvement of spatial attention to motor control progress after visual spatial training in subjects with unilateral spatial neglect (USN). 9 cases with USN after right cerebral stroke were randomly divided into Conventional treatment group + visual spatial attention and Conventional treatment group. The Conventional treatment group + visual spatial attention received conventional rehabilitation therapy (physical and occupational therapy) and visual spatial attention training (optokinetic stimulation and right half-field eye patching). The Conventional treatment group was only treated with conventional rehabilitation training (physical and occupational therapy). All patients were assessed by behavioral inattention test (BIT), Fugl-Meyer Assessment of motor function (FMA), equilibrium coordination test (ECT) and non-equilibrium coordination test (NCT) before and after 4 weeks treatment. Total scores in both groups (without visual spatial attention/with visual spatial attention) improved significantly (BIT: P=0.021/P=0.000, d=1.667/d=2.116, power=0.69/power=0.98, 95%CI[-0.8839,45.88]/95%CI=[16.96,92.64]; FMA: P=0.002/P=0.000, d=2.521/d=2.700, power=0.93/power=0.98, 95%CI[5.707,30.79]/95%CI=[16.06,53.94]; ECT: P=0.002/ P=0.000, d=2.031/d=1.354, power=0.90/power=0.17, 95%CI[3.380,42.61]/95%CI=[-1.478,39.08]; NCT: P=0.013/P=0.000, d=1.124/d=1.822, power=0.41/power=0.56, 95%CI[-7.980,37.48]/95%CI=[4.798,43.60],) after treatment. Among the 2 groups, the group with visual spatial attention significantly improved in BIT (P=0.003, d=3.103, power=1, 95%CI[15.68,48.92]), FMA of upper extremity (P=0.006, d=2.771, power=1, 95%CI[5.061,20.14]) and NCT (P=0.010, d=2.214, power=0.81-0.90, 95%CI[3.018,15.88]). Correlative analysis shows that the change of BIT scores is positively correlated to the change of FMA total score (r=0.77, Pvisual spatial training could

  13. Spatial Domain Adaptive Control of Nonlinear Rotary Systems Subject to Spatially Periodic Disturbances

    Directory of Open Access Journals (Sweden)

    Yen-Hsiu Yang

    2012-01-01

    Full Text Available We propose a generic spatial domain control scheme for a class of nonlinear rotary systems of variable speeds and subject to spatially periodic disturbances. The nonlinear model of the rotary system in time domain is transformed into one in spatial domain employing a coordinate transformation with respect to angular displacement. Under the circumstances that measurement of the system states is not available, a nonlinear state observer is established for providing the estimated states. A two-degree-of-freedom spatial domain control configuration is then proposed to stabilize the system and improve the tracking performance. The first control module applies adaptive backstepping with projected parametric update and concentrates on robust stabilization of the closed-loop system. The second control module introduces an internal model of the periodic disturbances cascaded with a loop-shaping filter, which not only further reduces the tracking error but also improves parametric adaptation. The overall spatial domain output feedback adaptive control system is robust to model uncertainties and state estimated error and capable of rejecting spatially periodic disturbances under varying system speeds. Stability proof of the overall system is given. A design example with simulation demonstrates the applicability of the proposed design.

  14. Separation of spatial-temporal patterns ('climatic modes') by combined analysis of really measured and generated numerically vector time series

    Science.gov (United States)

    Feigin, A. M.; Mukhin, D.; Volodin, E. M.; Gavrilov, A.; Loskutov, E. M.

    2013-12-01

    The new method of decomposition of the Earth's climate system into well separated spatial-temporal patterns ('climatic modes') is discussed. The method is based on: (i) generalization of the MSSA (Multichannel Singular Spectral Analysis) [1] for expanding vector (space-distributed) time series in basis of spatial-temporal empirical orthogonal functions (STEOF), which makes allowance delayed correlations of the processes recorded in spatially separated points; (ii) expanding both real SST data, and longer by several times SST data generated numerically, in STEOF basis; (iii) use of the numerically produced STEOF basis for exclusion of 'too slow' (and thus not represented correctly) processes from real data. The application of the method allows by means of vector time series generated numerically by the INM RAS Coupled Climate Model [2] to separate from real SST anomalies data [3] two climatic modes possessing by noticeably different time scales: 3-5 and 9-11 years. Relations of separated modes to ENSO and PDO are investigated. Possible applications of spatial-temporal climatic patterns concept to prognosis of climate system evolution is discussed. 1. Ghil, M., R. M. Allen, M. D. Dettinger, K. Ide, D. Kondrashov, et al. (2002) "Advanced spectral methods for climatic time series", Rev. Geophys. 40(1), 3.1-3.41. 2. http://83.149.207.89/GCM_DATA_PLOTTING/GCM_INM_DATA_XY_en.htm 3. http://iridl.ldeo.columbia.edu/SOURCES/.KAPLAN/.EXTENDED/.v2/.ssta/

  15. Daily Access to Sucrose Impairs Aspects of Spatial Memory Tasks Reliant on Pattern Separation and Neural Proliferation in Rats

    Science.gov (United States)

    Reichelt, Amy C.; Morris, Margaret J.; Westbrook, Reginald Frederick

    2016-01-01

    High sugar diets reduce hippocampal neurogenesis, which is required for minimizing interference between memories, a process that involves "pattern separation." We provided rats with 2 h daily access to a sucrose solution for 28 d and assessed their performance on a spatial memory task. Sucrose consuming rats discriminated between objects…

  16. Effect of spatial separation of pigs on spread of Streptococcus suis serotype 9.

    Directory of Open Access Journals (Sweden)

    Niels Dekker

    Full Text Available The spread of an infectious agent in a population can be reduced by interfering in the infectiousness or susceptibility of individuals, and/or in their contact structure. The aim of this study was to quantify the effect of prevention of direct contact between infectious and susceptible pigs on the transmission of Streptococcus suis (S. suis. In three replicate experiments, S. suis-free pigs were housed in boxes either in pairs (25 pairs or alone (15 pigs. The distance between the boxes was ±1 m. At 7 weeks of age, one pig of each pair was inoculated intranasally with S. suis serotype 9; the other pigs were exposed to S. suis by either direct (pairs or indirect contact (individually housed pigs. Tonsillar brush and saliva swab samples from all pigs were collected regularly for 4 weeks post inoculation to monitor colonization with S. suis. All inoculated pigs became infected, and their pen mates became colonized within 2 days. Thirteen indirectly exposed pigs became positive within 7-25 days after exposure. The rate of direct transmission βdir was estimated to be 3.58 per pig per day (95% CI: 2.29-5.60. The rate of indirect transmission increased in time, depending on the cumulative number of days pigs tested positive for the presence of S. suis. The estimate β'ind was 0.001 (95% CI: 0.0006-0.0017 new infections per pig per day for each day that an infected pig was tested positive for S. suis. We conclude that prevention of direct contact reduces the rate at which susceptible pigs become colonized. Simulation studies using these parameters showed, however, that such intervention measure would not limit S. suis serotype 9 spread in a commercial pig farm to a relevant extent, implying that spatial separation of groups op pigs within a compartment would not be effective on a farm.

  17. Environmental controls on multiscale spatial patterns of salt marsh vegetation

    DEFF Research Database (Denmark)

    Kim, Daehyun; Cairns, David; Bartholdy, Jesper

    2010-01-01

    In coastal environments, biogeographic patterns are generally influenced by surface elevation and horizontal distance from sea water. However, it is still unclear whether these major topographic factors are significant controls of vegetation patterns across spatial scales at which different physi...

  18. Cell-friendly inverse opal-like hydrogels for a spatially separated co-culture system.

    Science.gov (United States)

    Kim, Jaeyun; Bencherif, Sidi A; Li, Weiwei Aileen; Mooney, David J

    2014-09-01

    Three-dimensional macroporous scaffolds have extensively been studied for cell-based tissue engineering but their use is mostly limited to mechanical support for cell adhesion and growth on the surface of macropores. Here, a templated fabrication method is described to prepare cell-friendly inverse opal-like hydrogels (IOHs) allowing both cell encapsulation within the hydrogel matrix and cell seeding on the surface of macropores. Ionically crosslinked alginate microbeads and photocrosslinkable biocompatible polymers are used as a sacrificial template and as a matrix, respectively. The alginate microbeads are easily removed by a chelating agent, with minimal toxicity for the encapsulated cells during template removal. The outer surface of macropores in IOHs can also provide a space for cell adherence. The cells encapsulated or attached in IOHs are able to remain viable and to proliferate over time. The elastic modulus and cell-adhesion properties of IOHs can be easily controlled and tuned. Finally, it is demonstrated that IOH can be used to co-culture two distinct cell populations in different spatial positions. This cell-friendly IOH system provides a 3D scaffold for organizing different cell types in a controllable microenvironment to investigate biological processes such as stem cell niches or tumor microenvironments. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Controlled Topological Transitions in Thin-Film Phase Separation

    KAUST Repository

    Hennessy, Matthew G.; Burlakov, Victor M.; Goriely, Alain; Wagner, Barbara; Mü nch, Andreas

    2015-01-01

    © 2015 Society for Industrial and Applied Mathematics. In this paper the evolution of a binary mixture in a thin-film geometry with a wall at the top and bottom is considered. By bringing the mixture into its miscibility gap so that no spinodal decomposition occurs in the bulk, a slight energetic bias of the walls toward each one of the constituents ensures the nucleation of thin boundary layers that grow until the constituents have moved into one of the two layers. These layers are separated by an interfacial region where the composition changes rapidly. Conditions that ensure the separation into two layers with a thin interfacial region are investigated based on a phase-field model. Using matched asymptotic expansions a corresponding sharp-interface problem for the location of the interface is established. It is then argued that this newly created two-layer system is not at its energetic minimum but destabilizes into a controlled self-replicating pattern of trapezoidal vertical stripes by minimizing the interfacial energy between the phases while conserving their area. A quantitative analysis of this mechanism is carried out via a thin-film model for the free interfaces, which is derived asymptotically from the sharp-interface model.

  20. Separation control on the wing by jet actuators

    Science.gov (United States)

    Karyakin, O. M.; Nalivaiko, A. G.; Ustinov, M. V.; Flaxman, Ja. Sh.

    2018-05-01

    Use of jet actuators to eliminate flow separation is experimentally investigated on a straight wing with a NACA 0012 airfoil. It is shown that under the influence of synthetic jets the size of separation zone greatly reduces and the flow separation point displaces downstream. In addition, lift coefficient increases by more than 10%.

  1. Magnetic particle separation using controllable magnetic force switches

    International Nuclear Information System (INIS)

    Wei Zunghang; Lee, C.-P.; Lai, M.-F.

    2010-01-01

    Magnetic particle separation is very important in biomedical applications. In this study, a magnetic particle microseparator is proposed that uses micro magnets to produce open/closed magnetic flux for switching on/off the separation. When all magnets are magnetized in the same direction, the magnetic force switch for separation is on; almost all magnetic particles are trapped in the channel side walls and the separation rate can reach 95%. When the magnetization directions of adjacent magnets are opposite, the magnetic force switch for separation is off, and most magnetic particles pass through the microchannel without being trapped. For the separation of multi-sized magnetic particles, the proposed microseparator is numerically demonstrated to have high separation rate.

  2. Many-body correlation effects in the spatially separated electron and hole layers in the coupled quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Babichenko, V.S. [RRC Kurchatov Institute, Kurchatov Sq., 1, 123182 Moscow (Russian Federation); Polishchuk, I.Ya., E-mail: iyppolishchuk@gmail.com [RRC Kurchatov Institute, Kurchatov Sq., 1, 123182 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 141700, 9, Institutskii per., Dolgoprudny, Moscow Region (Russian Federation)

    2014-11-15

    The many-body correlation effects in the spatially separated electron and hole layers in the coupled quantum wells are investigated. A special case of the many-component electron–hole system is considered. It is shown that if the hole mass is much greater than the electron mass, the negative correlation energy is mainly determined by the holes. The ground state of the system is found to be the 2D electron–hole liquid with the energy smaller than the exciton phase. It is shown that the system decays into the spatially separated neutral electron–hole drops if the initially created charge density in the layers is smaller than the certain critical value n{sub eq}.

  3. Grey-grey separate spatial soliton pairs in a biased series two-photon centrosymmetric photorefractive crystals circuit

    International Nuclear Information System (INIS)

    Ji, Xuanmang; Wang, Jinlai; Jiang, Qichang; Liu, Jinsong

    2012-01-01

    Grey-grey separate spatial soliton pairs are predicted in a biased series circuit consisting of two centrosymmetric photorefractive (PR) crystals with the two-photon PR effect. The numerical results show that two grey solitons in a soliton pair can affect each other by the light-induced current. The effects of the intensity of solitary waves and gating lights on the normalized profiles and the dynamical evolutions of solitons are discussed.

  4. Correlation of propagation characteristics of solar cosmic rays detected onboard the spatially separated space probes Mars-7 and Prognoz-3

    International Nuclear Information System (INIS)

    Gombosi, T.; Somogyi, A.J.; Kolesov, G.Ya.; Kurt, V.G.; Kuzhevskii, B.M.; Logachev, Yu.I.; Savenko, I.A.

    1977-01-01

    Solar flare generated particle fluxes during the period 3-5 November, 1973 are analysed using the data of the Mars 7 and Prognoz-3 spacecrafts. The intensity profiles registrated onboard these satellites were quite similar, although the space probes were spatially separated by 0.3 AU. The general characteristics of the event can well be understood in terms of the effect of a corotating streat-stream interaction region on the general behaviour of energetic charged particles. (author)

  5. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Measurement of wavefront distortions by the method of aperture sounding with spatially separated channels

    Science.gov (United States)

    Prilepskiy, Boris V.; Alikhanov, Alexey N.; Berchenko, Evgeniy A.; Kiselev, Vladimir Yu; Narusbek, Ernest A.; Filatov, Aleksander S.

    2005-08-01

    Features of the formation of signals in wavefront sensors with the single-frequency light wave phase modulation and spatial separation of control channels are considered. Analysis is performed for sensors in which phase modulation is governed by a controlled element located in the pupil of the optical system of a sensor or in the focal plane of the objective of this system. Peculiarities of the signal formation for a tilted wavefront are considered separately for internal points of the exit pupil in the case of light wave phase modulation in the pupil. It is shown that a signal at the modulation frequency in these wavefront sensors for points located far from the pupil boundaries is determined by the wavefront curvature.

  6. Structural Changes of PVDF Membranes by Phase Separation Control

    International Nuclear Information System (INIS)

    Lee, Semin; Kim, Sung Soo

    2016-01-01

    Thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) were simultaneously induced for the preparation of flat PVDF membranes. N-methyl-2-pyrrolidone (NMP) was used as a solvent and dibutyl-phthlate (DBP) was used as a diluent for PVDF. When PVDF was melt blended with NMP and DBP, crystallization temperature was lowered for TIPS and unstable region was expanded for NIPS. Ratio of solvent to diluent changed the phase separation mechanism to obtain the various membrane structures. Contact mode of dope solution with nonsolvent determined the dominant phase separation behavior. Since heat transfer rate was greater than mass transfer rate, surface structure was formed by NIPS and inner structure was by TIPS. Quenching temperature of dope solution also affected the phase separation mechanism and phase separation rate to result in the variation of structure

  7. Multicollinearity in spatial genetics: separating the wheat from the chaff using commonality analyses.

    Science.gov (United States)

    Prunier, J G; Colyn, M; Legendre, X; Nimon, K F; Flamand, M C

    2015-01-01

    Direct gradient analyses in spatial genetics provide unique opportunities to describe the inherent complexity of genetic variation in wildlife species and are the object of many methodological developments. However, multicollinearity among explanatory variables is a systemic issue in multivariate regression analyses and is likely to cause serious difficulties in properly interpreting results of direct gradient analyses, with the risk of erroneous conclusions, misdirected research and inefficient or counterproductive conservation measures. Using simulated data sets along with linear and logistic regressions on distance matrices, we illustrate how commonality analysis (CA), a detailed variance-partitioning procedure that was recently introduced in the field of ecology, can be used to deal with nonindependence among spatial predictors. By decomposing model fit indices into unique and common (or shared) variance components, CA allows identifying the location and magnitude of multicollinearity, revealing spurious correlations and thus thoroughly improving the interpretation of multivariate regressions. Despite a few inherent limitations, especially in the case of resistance model optimization, this review highlights the great potential of CA to account for complex multicollinearity patterns in spatial genetics and identifies future applications and lines of research. We strongly urge spatial geneticists to systematically investigate commonalities when performing direct gradient analyses. © 2014 John Wiley & Sons Ltd.

  8. Evidence for Separate Contributions of High and Low Spatial Frequencies during Visual Word Recognition.

    Science.gov (United States)

    Winsler, Kurt; Holcomb, Phillip J; Midgley, Katherine J; Grainger, Jonathan

    2017-01-01

    Previous studies have shown that different spatial frequency information processing streams interact during the recognition of visual stimuli. However, it is a matter of debate as to the contributions of high and low spatial frequency (HSF and LSF) information for visual word recognition. This study examined the role of different spatial frequencies in visual word recognition using event-related potential (ERP) masked priming. EEG was recorded from 32 scalp sites in 30 English-speaking adults in a go/no-go semantic categorization task. Stimuli were white characters on a neutral gray background. Targets were uppercase five letter words preceded by a forward-mask (#######) and a 50 ms lowercase prime. Primes were either the same word (repeated) or a different word (un-repeated) than the subsequent target and either contained only high, only low, or full spatial frequency information. Additionally within each condition, half of the prime-target pairs were high lexical frequency, and half were low. In the full spatial frequency condition, typical ERP masked priming effects were found with an attenuated N250 (sub-lexical) and N400 (lexical-semantic) for repeated compared to un-repeated primes. For HSF primes there was a weaker N250 effect which interacted with lexical frequency, a significant reversal of the effect around 300 ms, and an N400-like effect for only high lexical frequency word pairs. LSF primes did not produce any of the classic ERP repetition priming effects, however they did elicit a distinct early effect around 200 ms in the opposite direction of typical repetition effects. HSF information accounted for many of the masked repetition priming ERP effects and therefore suggests that HSFs are more crucial for word recognition. However, LSFs did produce their own pattern of priming effects indicating that larger scale information may still play a role in word recognition.

  9. Spatially and temporally controlled hydrogels for tissue engineering

    NARCIS (Netherlands)

    J., Leijten; Seo, Jungmok; Yue, Kan; Trujillo-de Santiago, Grissel; Tamayol, Ali; Ruiz-Esparza, Guillermo U.; Ryon Shin, Su; Sharifi, Roholah; Noshadi, Iman; Moises Alvarez, Mario; Shrike Zhang, Yu; Khademhosseini, Ali

    2017-01-01

    Recent years have seen tremendous advances in the field of hydrogel-based biomaterials. One of the most prominent revolutions in this field has been the integration of elements or techniques that enable spatial and temporal control over hydrogels’ properties and functions. Here, we critically review

  10. Controlled Fabrication of Metallic Electrodes with Atomic Separation

    DEFF Research Database (Denmark)

    Morpurgo, A.; Robinson, D.; M. Marcus, C.

    1998-01-01

    We report a new technique for fabricating metallic electrodes on insulating substrates with separations on the 1 nm scale. The fabrication technique, which combines lithographic and electrochemical methods, provides atomic resolution without requiring sophisticated instrumentation. The process is...

  11. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Science.gov (United States)

    Dickel, T.; Plaß, W. R.; Ayet San Andres, S.; Ebert, J.; Geissel, H.; Haettner, E.; Hornung, C.; Miskun, I.; Pietri, S.; Purushothaman, S.; Reiter, M. P.; Rink, A.-K.; Scheidenberger, C.; Weick, H.; Dendooven, P.; Diwisch, M.; Greiner, F.; Heiße, F.; Knöbel, R.; Lippert, W.; Moore, I. D.; Pohjalainen, I.; Prochazka, A.; Ranjan, M.; Takechi, M.; Winfield, J. S.; Xu, X.

    2015-05-01

    211Po ions in the ground and isomeric states were produced via 238U projectile fragmentation at 1000 MeV/u. The 211Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC). They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  12. Demonstration of the spatial separation of the entangled quantum sidebands of an optical field

    International Nuclear Information System (INIS)

    Huntington, E.H.; Milford, G.N.; Robilliard, C.; Ralph, T.C.; Gloeckl, O.; Andersen, U.L.; Lorenz, S.; Leuchs, G.

    2005-01-01

    Quantum optics experiments on 'bright' beams are based on the spectral analysis of field fluctuations and typically probe correlations between radio-frequency sideband modes. However, the extra degree of freedom represented by this dual-mode picture is generally ignored. We demonstrate the experimental operation of a device which can be used to separate the quantum sidebands of an optical field. We use this device to explicitly demonstrate the quantum entanglement between the sidebands of a squeezed beam

  13. Interspecific and intraspecific spatial separation by birds breeding in nest boxes

    Directory of Open Access Journals (Sweden)

    Denis C. Deeming

    2017-12-01

    Full Text Available Nest boxes can be seen as a conservation tool for improving low-grade nesting habitat but it is unclear how sympatric species using boxes establish a spatial distribution relative to conspecifics and heterospecifics. This study determined the distances between nest boxes occupied by Blue Tits (Cyanistes caeruleus and Great Tits (Parus major in two British woodlands to ascertain whether spatial distribution was affected by species and, if it was, whether there were reproductive consequences of this breeding distribution. Occupancy of nest boxes at two woodland sites were recorded on an annual basis between 2010 and 2014, inclusive. Distances between nest boxes, and reproductive activity, were recorded. Even if nest boxes showed a clumped distribution in the woodlands, the occupancy of the boxes was random. Not all boxes were used and the minimum distance between occupied boxes was at least twice the distance between boxes in general. Blue Tits tended to have greater distances between boxes containing conspecifics but distances between boxes containing heterospecifics were generally of comparable lengths. Reproductive output was only affected in relation to clutch size for Blue Tits nesting at one site. Nest boxes that aim to improve habitats that lack suitable nesting sites should be placed to reflect actual dispersal distances of the focal bird species.

  14. Control strategies for laser separation of carbon isotopes

    Indian Academy of Sciences (India)

    Laser isotope separation (LIS) by infrared laser chemistry of polyatomic molecules has come a long way since its discovery. The last decade has seen considerable efforts in scaling up of the process for light elements like carbon, oxygen and silicon. These efforts aim at ways to improve both the enrichment factor and the ...

  15. Spatial orientation and postural control in patients with Parkinson's disease.

    Science.gov (United States)

    Pawlitzki, E; Schlenstedt, C; Schmidt, N; Rotkirch, I; Gövert, F; Hartwigsen, G; Witt, K

    2018-02-01

    Postural instability is one of the most disabling and risky symptoms of advanced Parkinson's disease (PD). The purpose of this study was to investigate whether and how this is mediated by a centrally impaired spatial orientation. Therefore, we performed a spatial orientation study in 21 PD patients (mean age 68years, SD 8.5 years, 9 women) in a medically on condition and 21 healthy controls (mean age 68.9years, SD 5.5years, 14 women). We compared their spatial responses to the horizontal axis (Sakashita's visual target cancellation task), the vertical axis (bucket-test), the sagittal axis (tilt table test) and postural stability using the Fullerton Advanced Balance Scale (FAB). We found larger deviations on the vertical axis in PD patients, although the direct comparisons of performance in PD patients and healthy controls did not reveal significant differences. While the total scores of the FAB Scale were significantly worse in PD (25.9 points, SD 7.2 points) compared to controls (35.1 points, SD 2.3 points, pbalance control. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Deciphering factors controlling groundwater arsenic spatial variability in Bangladesh

    Science.gov (United States)

    Tan, Z.; Yang, Q.; Zheng, C.; Zheng, Y.

    2017-12-01

    Elevated concentrations of geogenic arsenic in groundwater have been found in many countries to exceed 10 μg/L, the WHO's guideline value for drinking water. A common yet unexplained characteristic of groundwater arsenic spatial distribution is the extensive variability at various spatial scales. This study investigates factors influencing the spatial variability of groundwater arsenic in Bangladesh to improve the accuracy of models predicting arsenic exceedance rate spatially. A novel boosted regression tree method is used to establish a weak-learning ensemble model, which is compared to a linear model using a conventional stepwise logistic regression method. The boosted regression tree models offer the advantage of parametric interaction when big datasets are analyzed in comparison to the logistic regression. The point data set (n=3,538) of groundwater hydrochemistry with 19 parameters was obtained by the British Geological Survey in 2001. The spatial data sets of geological parameters (n=13) were from the Consortium for Spatial Information, Technical University of Denmark, University of East Anglia and the FAO, while the soil parameters (n=42) were from the Harmonized World Soil Database. The aforementioned parameters were regressed to categorical groundwater arsenic concentrations below or above three thresholds: 5 μg/L, 10 μg/L and 50 μg/L to identify respective controlling factors. Boosted regression tree method outperformed logistic regression methods in all three threshold levels in terms of accuracy, specificity and sensitivity, resulting in an improvement of spatial distribution map of probability of groundwater arsenic exceeding all three thresholds when compared to disjunctive-kriging interpolated spatial arsenic map using the same groundwater arsenic dataset. Boosted regression tree models also show that the most important controlling factors of groundwater arsenic distribution include groundwater iron content and well depth for all three

  17. Control of Spin Wave Dynamics in Spatially Twisted Magnetic Structures

    Science.gov (United States)

    2017-06-27

    control the spin wave dynamics of magnetic structures twisted spatially, we prepared the exchange-coupled films with the hard magnetic L10-FePt and...information writing of magnetic storage and spintronic applications. Introduction and Objective: Recent rapid progress in the research field of nano...scaled bilayer elements is also an important aim of this project. Approach/Method: The exchange-coupled films with the hard magnetic L10-FePt and

  18. Models of the Dynamics of Spatially Separated Broadband Electromagnetic Fields Interacting with Resonant Atoms

    Science.gov (United States)

    Basharov, A. M.

    2018-03-01

    The Markov model of spontaneous emission of an atom localized in a spatial region with a broadband electromagnetic field with zero photon density is considered in the conditions of coupling of the electromagnetic field with the broadband field of a neighboring space. The evolution operator of the system and the kinetic equation for the atom are obtained. It is shown that the field coupling constant affects the rate of spontaneous emission of the atom, but is not manifested in the atomic frequency shift. The analytic expression for the radiative decay constant for the atom is found to be analogous in a certain sense to the expression for the decay constant for a singly excited localized ensemble of identical atoms in the conditions when the effect of stabilization of its excited state by the Stark interaction with the vacuum broadband electromagnetic field is manifested. The model is formulated based on quantum stochastic differential equations of the non- Wiener type and the generalized algebra of the Ito differential of quantum random processes.

  19. Spatial and temporal analysis of postural control in dyslexic children.

    Science.gov (United States)

    Gouleme, Nathalie; Gerard, Christophe Loic; Bui-Quoc, Emmanuel; Bucci, Maria Pia

    2015-07-01

    The aim of this study is to examine postural control of dyslexic children using both spatial and temporal analysis. Thirty dyslexic (mean age 9.7±0.3years) and thirty non-dyslexic age-matched children participated in the study. Postural stability was evaluated using Multitest Equilibre from Framiral®. Posture was recorded in the following conditions: eyes open fixating a target (EO) and eyes closed (EC) on stable (-S-) and unstable (-U-) platforms. The findings of this study showed poor postural stability in dyslexic children with respect to the non-dyslexic children group, as demonstrated by both spatial and temporal analysis. In both groups of children postural control depends on the condition, and improves when the eyes are open on a stable platform. Dyslexic children have spectral power indices that are higher than in non-dyslexic children and they showed a shorter cancelling time. Poor postural control in dyslexic children could be due to a deficit in using sensory information most likely caused by impairment in cerebellar activity. The reliability of brain activation patterns, namely in using sensory input and cerebellar activity may explain the deficit in postural control in dyslexic children. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  20. Process control measurements in the SRP fuel separations plants

    International Nuclear Information System (INIS)

    McKibben, J.M.; Pickett, C.E.; Dickert, H.D.

    1982-02-01

    Programs were started to develop new in-line and at-line analytical techniques. Among the more promising techniques being investigated are: (1) an in-line instrument to analyze for percent tributyl phosphate in process solvent, (2) remote laser optrode techniques (using lazer light transmitted to and from the sample cell via light pipes) for a variety of possible analyses, and (3) sonic techniques for concentration analyses in two component systems. A subcommittee was also formed to investigate state-of-the-technology for process control. The final recommendation was to use a distributed control approach to upgrade the process control sytem. The system selected should be modular, easy to expand, and simple to change control strategies. A distributed system using microprocessorbased controllers would allow installation of the control intelligence near the process, thereby simplifying field wiring. Process information collected and stored in the controllers will be transmitted to operating consoles, via a data highway, for process management and display. The overall program has a number of distinct benefits. There are a number of cost savings that will be realized. Excellent annual return on investment - up to 110% - has been predicted for several of the projects in this program that are already funded. In addition, many of the instrument modifications will improve safety performance and production throughput in the specific ways shown

  1. Low-bias negative differential conductance controlled by electrode separation

    Science.gov (United States)

    Yi, Xiao-Hua; Liu, Ran; Bi, Jun-Jie; Jiao, Yang; Wang, Chuan-Kui; Li, Zong-Liang

    2016-12-01

    The electronic transport properties of a single thiolated arylethynylene molecule with 9,10-dihydroanthracene core, denoted as TADHA, is studied by using non-equilibrium Green’s function formalism combined with ab initio calculations. The numerical results show that the TADHA molecule exhibits excellent negative differential conductance (NDC) behavior at lower bias regime as probed experimentally. The NDC behavior of TADHA molecule originates from the Stark effect of the applied bias voltage, by which the highest occupied molecular orbital (HOMO) and the HOMO-1 are pulled apart and become localized. The NDC behavior of TADHA molecular system is tunable by changing the electrode distance. Shortening the electrode separation can enhance the NDC effect which is attributed to the possible increase of coupling between the two branches of TADHA molecule. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374195 and 11405098) and the Natural Science Foundation of Shandong Province, China (Grant No. ZR2013FM006).

  2. Low-bias negative differential conductance controlled by electrode separation

    International Nuclear Information System (INIS)

    Yi Xiao-Hua; Liu Ran; Bi Jun-Jie; Jiao Yang; Wang Chuan-Kui; Li Zong-Liang

    2016-01-01

    The electronic transport properties of a single thiolated arylethynylene molecule with 9,10-dihydroanthracene core, denoted as TADHA, is studied by using non-equilibrium Green’s function formalism combined with ab initio calculations. The numerical results show that the TADHA molecule exhibits excellent negative differential conductance (NDC) behavior at lower bias regime as probed experimentally. The NDC behavior of TADHA molecule originates from the Stark effect of the applied bias voltage, by which the highest occupied molecular orbital (HOMO) and the HOMO-1 are pulled apart and become localized. The NDC behavior of TADHA molecular system is tunable by changing the electrode distance. Shortening the electrode separation can enhance the NDC effect which is attributed to the possible increase of coupling between the two branches of TADHA molecule. (paper)

  3. Theory of fourfold interference with photon pairs from spatially separated sources

    International Nuclear Information System (INIS)

    Zhang, Hui Rong; Wang, Ruo Peng

    2007-01-01

    We present a theory for fourfold quantum interference of photons generated from independent spontaneous parametric down-conversion processes. Closed-form expressions for fourfold quantum interference patterns and visibility are found. The theoretical result for fourfold quantum interference patterns is in good agreement with experimental data reported. Detailed numerical calculations for the dependence of fourfold quantum interference visibility on experimentally controllable parameters are carried out. It is found out that higher visibility can be achieved for small biphoton width, short pump pulse coherence time, and narrow bandwidth of spectral filters. The optimal condition for obtaining at the same time higher fourfold interference visibility and intensity is also discussed

  4. Separate individual control systems come together at EP2

    International Nuclear Information System (INIS)

    Podmore, A.

    1991-01-01

    At BNFL's EP2 radioactive waste encapsulation plant in the UK, eight area supervisory control and data acquisition systems (SCADAs) and one central SCADA are being installed to provide computer-controlled processing of waste drums. The individual systems are all autonomous, minimizing the effect they have on other areas of the process. At the same time, they are part of an integrated system which provides effective communication between the various areas. (author)

  5. Amplitude and Phase Characteristics of Signals at the Output of Spatially Separated Antennas for Paths with Scattering

    Science.gov (United States)

    Anikin, A. S.

    2018-06-01

    Conditional statistical characteristics of the phase difference are considered depending on the ratio of instantaneous output signal amplitudes of spatially separated weakly directional antennas for the normal field model for paths with radio-wave scattering. The dependences obtained are related to the physical processes on the radio-wave propagation path. The normal model parameters are established at which the statistical characteristics of the phase difference depend on the ratio of the instantaneous amplitudes and hence can be used to measure the phase difference. Using Shannon's formula, the amount of information on the phase difference of signals contained in the ratio of their amplitudes is calculated depending on the parameters of the normal field model. Approaches are suggested to reduce the shift of phase difference measured for paths with radio-wave scattering. A comparison with results of computer simulation by the Monte Carlo method is performed.

  6. Large Spatial and Temporal Separations of Cause and Effect in Policy Making - Dealing with Non-linear Effects

    Science.gov (United States)

    McCaskill, John

    There can be large spatial and temporal separation of cause and effect in policy making. Determining the correct linkage between policy inputs and outcomes can be highly impractical in the complex environments faced by policy makers. In attempting to see and plan for the probable outcomes, standard linear models often overlook, ignore, or are unable to predict catastrophic events that only seem improbable due to the issue of multiple feedback loops. There are several issues with the makeup and behaviors of complex systems that explain the difficulty many mathematical models (factor analysis/structural equation modeling) have in dealing with non-linear effects in complex systems. This chapter highlights those problem issues and offers insights to the usefulness of ABM in dealing with non-linear effects in complex policy making environments.

  7. Direct conversion of a three-atom W state to a Greenberger–Horne–Zeilinger state in spatially separated cavities

    International Nuclear Information System (INIS)

    Wang, Guo-Yuan; Wang, Dong-Yang; Cui, Wen-Xue; Wang, Hong-Fu; Zhu, Ai-Dong; Zhang, Shou

    2016-01-01

    State conversion between the Greenberger–Horne–Zeilinger (GHZ) state and the W state is a challenging open problem because these states cannot be converted to each other by just local operations and classical communication. Here we propose a cavity quantum electrodynamics method based on interference of polarized photons emitted by the atoms trapped in spatially separated optical cavities that can convert a three-atom W state to a GHZ state. We calculate the success probability and fidelity of the converted GHZ state when the cavity decay, spontaneous atomic decay and photon leakage of the cavities are taken into account for a practical system, which shows that the proposed scheme is feasible and within the reach of current experimental technology. (paper)

  8. Control and Resistance in the Heterotopic Spatiality of Pleasantville

    Directory of Open Access Journals (Sweden)

    Evrim ERSÖZ KOÇ

    2016-02-01

    Full Text Available Pleasantville presents the experience of the teenage twins David and Jennifer who are transported to the 1950s TV soap opera named Pleasantville via the TV remote control. The twins introduce free sex, arts, literature, rock and roll, and jazz to this perfected town in which residents live in order. This clash of cultures results in social unrest as the residents become aware that the order is an outcome of submission and challenge the roles attributed to them. The transformation from control to resistance is the dominant motif of the film. Using Foucault’s theory of heterotopia, this study scrutinizes how the heterotopian principles in the spatial presentations provide a good lens to negotiate forms of control and resistance.

  9. Hilar GABAergic Interneuron Activity Controls Spatial Learning and Memory Retrieval

    Science.gov (United States)

    Andrews-Zwilling, Yaisa; Gillespie, Anna K.; Kravitz, Alexxai V.; Nelson, Alexandra B.; Devidze, Nino; Lo, Iris; Yoon, Seo Yeon; Bien-Ly, Nga; Ring, Karen; Zwilling, Daniel; Potter, Gregory B.; Rubenstein, John L. R.; Kreitzer, Anatol C.; Huang, Yadong

    2012-01-01

    Background Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD), the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear. Methodology and Principal Findings We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0)—a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity. Conclusions and Significance Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD. PMID:22792368

  10. Hilar GABAergic interneuron activity controls spatial learning and memory retrieval.

    Directory of Open Access Journals (Sweden)

    Yaisa Andrews-Zwilling

    Full Text Available Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD, the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear.We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0--a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity.Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD.

  11. The separated-sector cyclotron : the control system

    International Nuclear Information System (INIS)

    1991-01-01

    The old control system of the National Accelerator Centre remains fully operational while the networked system is being used to control new facilities. The latter system is still being developed, particularly with regard to the human interface. The data acquisition and graphic display facility is also being developed, to replace obsolete hardware. Several other graphics display and database packages are being developed to satisfy specific needs. Both hardware and software upgrades are being implemented as more facilities become available for the new operating system. 2 figs

  12. Photonic lantern adaptive spatial mode control in LMA fiber amplifiers.

    Science.gov (United States)

    Montoya, Juan; Aleshire, Chris; Hwang, Christopher; Fontaine, Nicolas K; Velázquez-Benítez, Amado; Martz, Dale H; Fan, T Y; Ripin, Dan

    2016-02-22

    We demonstrate adaptive-spatial mode control (ASMC) in few-moded double-clad large mode area (LMA) fiber amplifiers by using an all-fiber-based photonic lantern. Three single-mode fiber inputs are used to adaptively inject the appropriate superposition of input modes in a multimode gain fiber to achieve the desired mode at the output. By actively adjusting the relative phase of the single-mode inputs, near-unity coherent combination resulting in a single fundamental mode at the output is achieved.

  13. Prokaryotes in subsoil – evidence for spatial separation of oligotrophs and copiotrophs by co-occurrence networks

    Directory of Open Access Journals (Sweden)

    Michael eSchloter

    2015-11-01

    Full Text Available Soil microbial communities provide a wide range of soil functions including nutrient cycling, soil formation, and plant growth promotion. On the small scale, nutrient rich soil hotspots developed from soil animal or plant activity are important drivers for microbial communities and their activity pattern. Nevertheless, in subsoil, the spatial heterogeneity of microbes with diverging lifestyles has been barely considered so far. In this study, the phylogenetic composition of the bacterial and archaeal microbiome based on 16S rRNA gene pyrosequencing was investigated in the soil compartments bulk soil, drilosphere, and rhizosphere in topsoil and in the subsoil of an agricultural field. With co-occurrence network analysis, the spatial separation of typically oligotrophs and heterotrophs in subsoil and hotspots was assessed. Four co-occurring bacterial communities were identified and attributed to bulk topsoil, bulk subsoil, drilosphere, and rhizosphere. The bacterial phyla Proteobacteria and Bacteroidetes, which represent many copiotrophic bacteria, are affiliated to the hotspot communities – the rhizosphere and drilosphere – both in topsoil and subsoil. Acidobacteria, Actinobacteria, Gemmatimonadetes, Planctomycetes, and Verrucomicrobia with many oligotrophic bacteria, are the abundant groups of the bulk subsoil community. The bacterial core microbiome in this soil was estimated and only covers 7.6% of the bacterial sequencing reads but includes both oligotrophic and copiotrophic bacteria. Instead, the archaeal core microbiome includes 56% of the overall archaeal diversity and comprises only the ammonium oxidizing Nitrososphaera. Thus, the spatial variability of nutrient quality and quantity strongly shapes the bacterial community composition and their interaction in subsoil, whereas archaea are a stable backbone of the soil prokaryotes.

  14. Separating active and passive influences on stomatal control of transpiration.

    Science.gov (United States)

    McAdam, Scott A M; Brodribb, Timothy J

    2014-04-01

    Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior.

  15. A Novel Approach to Adaptive Flow Separation Control

    Science.gov (United States)

    2016-09-03

    Artificial Intelligence ( ) TOTAL: 1 Books Number of Manuscripts: Patents Submitted Patents Awarded Awards Graduate Students Names of Post Doctorates...Education, February 2015. ASME Fellow, April 2013. Received Book TOTAL: Received Book Chapter TOTAL: PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number...and other fields such as power system control and automotive engine tuning. References 1. B. Reese, F. Alvi, and E. G. Collins, “A

  16. Pilot and Controller Evaluations of Separation Function Allocation in Air Traffic Management

    Science.gov (United States)

    Wing, David; Prevot, Thomas; Morey, Susan; Lewis, Timothy; Martin, Lynne; Johnson, Sally; Cabrall, Christopher; Como, Sean; Homola, Jeffrey; Sheth-Chandra, Manasi; style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20130014930'); toggleEditAbsImage('author_20130014930_show'); toggleEditAbsImage('author_20130014930_hide'); "> style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20130014930_show"> style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20130014930_hide">

    2013-01-01

    Two human-in-the-loop simulation experiments were conducted in coordinated fashion to investigate the allocation of separation assurance functions between ground and air and between humans and automation. The experiments modeled a mixed-operations concept in which aircraft receiving ground-based separation services shared the airspace with aircraft providing their own separation service (i.e., self-separation). Ground-based separation was provided by air traffic controllers without automation tools, with tools, or by ground-based automation with controllers in a managing role. Airborne self-separation was provided by airline pilots using self-separation automation enabled by airborne surveillance technology. The two experiments, one pilot-focused and the other controller-focused, addressed selected key issues of mixed operations, assuming the starting point of current-day operations and modeling an emergence of NextGen technologies and procedures. In the controller-focused experiment, the impact of mixed operations on controller performance was assessed at four stages of NextGen implementation. In the pilot-focused experiment, the limits to which pilots with automation tools could take full responsibility for separation from ground-controlled aircraft were tested. Results indicate that the presence of self-separating aircraft had little impact on the controllers' ability to provide separation services for ground-controlled aircraft. Overall performance was best in the most automated environment in which all aircraft were data communications equipped, ground-based separation was highly automated, and self-separating aircraft had access to trajectory intent information for all aircraft. In this environment, safe, efficient, and highly acceptable operations could be achieved for twice today's peak airspace throughput. In less automated environments, reduced trajectory intent exchange and manual air traffic control limited the safely achievable airspace throughput and

  17. A fuzzy controlled three-phase centrifuge for waste separation

    International Nuclear Information System (INIS)

    Parkinson, W.J.; Smith, R.E.; Miller, N.

    1998-02-01

    The three-phase centrifuge technology discussed in this paper was developed by Neal Miller, president of Centech, Inc. The three-phase centrifuge is an excellent device for cleaning up oil field and refinery wastes which are typically composed of hydrocarbons, water, and solids. The technology is unique. It turns the waste into salable oil, reusable water, and landfill-able solids. No secondary waste is produced. The problem is that only the inventor can set up and run the equipment well enough to provide an optimal cleanup. Demand for this device has far exceeded a one man operation. There is now a need for several centrifuges to be operated at different locations at the same time. This has produced a demand for an intelligent control system, one that could replace a highly skilled operator, or at least supplement the skills of a less experienced operator. The control problem is ideally suited to fuzzy logic, since the centrifuge is a highly complicated machine operated entirely by the skill and experience of the operator. A fuzzy control system was designed for and used with the centrifuge

  18. Controlling Interfacial Separation in Porous Structures by Void Patterning

    Science.gov (United States)

    Ghareeb, Ahmed; Elbanna, Ahmed

    Manipulating interfacial response for enhanced adhesion or fracture resistance is a problem of great interest to scientists and engineers. In many natural materials and engineering applications, an interface exists between a porous structure and a substrate. A question that arises is how the void distribution in the bulk may affect the interfacial response and whether it is possible to alter the interfacial toughness without changing the surface physical chemistry. In this paper, we address this question by studying the effect of patterning voids on the interfacial-to-the overall response of an elastic plate glued to a rigid substrate by bilinear cohesive material. Different patterning categories are investigated; uniform, graded, and binary voids. Each case is subjected to upward displacement at the upper edge of the plate. We show that the peak force and maximum elongation at failure depend on the voids design and by changing the void size, alignment or gradation we may control these performance measures. We relate these changes in the measured force displacement response to energy release rate as a measure of interfacial toughness. We discuss the implications of our results on design of bulk heterogeneities for enhanced interfacial behavior.

  19. Controls of Soil Spatial Variability in a Dry Tropical Forest.

    Directory of Open Access Journals (Sweden)

    Sandeep Pulla

    Full Text Available We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2 soil spatial variability in a seasonally dry tropical forest (SDTF in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm, rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH, and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(--N nor NH4(+-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

  20. Active vibration control of spatial flexible multibody systems

    Energy Technology Data Exchange (ETDEWEB)

    Neto, Maria Augusta, E-mail: augusta.neto@dem.uc.pt [Universidade de Coimbra (Polo II), Departamento de Engenharia Mecanica, Faculdade de Ciencia e Tecnologia (Portugal); Ambrosio, Jorge A. C., E-mail: jorge@dem.ist.utl.pt [Instituto Superior Tecnico, Instituto de Engenharia Mecanica (Portugal); Roseiro, Luis M., E-mail: lroseiro@isec.pt [Instituto Superior de Engenharia de Coimbra, Departamento de Engenharia Mecanica (Portugal); Amaro, A., E-mail: ana.amaro@dem.uc.pt [Universidade de Coimbra (Polo II), Departamento de Engenharia Mecanica, Faculdade de Ciencia e Tecnologia (Portugal); Vasques, C. M. A., E-mail: cvasques@inegi.up.pt [Universidade do Porto, INEGI-Instituto de Engenharia Mecanica e Gestao Industrial (Portugal)

    2013-06-15

    In this work a flexible multibody dynamics formulation of complex models including elastic components made of composite materials is extended to include piezoelectric sensors and actuators. The only limitation for the deformation of a structural member is that they must remain elastic and linear when described in a coordinate frame fixed to a material point or region of its domain. The flexible finite-element model of each flexible body is obtained referring the flexible body nodal coordinates to the body fixed frame and using a diagonalized mass description of the inertia in the mass matrix and on the gyroscopic force vector. The modal superposition technique is used to reduce the number of generalized coordinates to a reasonable dimension for complex shaped structural models of flexible bodies. The active vibration control of the flexible multibody components is implemented using an asymmetric collocated piezoelectric sensor/actuator pair. An electromechanically coupled model is taken into account to properly consider the surface-bonded piezoelectric transducers and their effects on the time and spatial response of the flexible multibody components. The electromechanical effects are introduced in the flexible multibody equations of motion by the use of beam and plate/shell elements, developed to this purpose. A comparative study between the classical control strategies, constant gain and amplitude velocity feedback, and optimal control strategy, linear quadratic regulator (LQR), is performed in order to investigate their effectiveness to suppress vibrations in structures with piezoelectric sensing and actuating patches.

  1. Active vibration control of spatial flexible multibody systems

    International Nuclear Information System (INIS)

    Neto, Maria Augusta; Ambrósio, Jorge A. C.; Roseiro, Luis M.; Amaro, A.; Vasques, C. M. A.

    2013-01-01

    In this work a flexible multibody dynamics formulation of complex models including elastic components made of composite materials is extended to include piezoelectric sensors and actuators. The only limitation for the deformation of a structural member is that they must remain elastic and linear when described in a coordinate frame fixed to a material point or region of its domain. The flexible finite-element model of each flexible body is obtained referring the flexible body nodal coordinates to the body fixed frame and using a diagonalized mass description of the inertia in the mass matrix and on the gyroscopic force vector. The modal superposition technique is used to reduce the number of generalized coordinates to a reasonable dimension for complex shaped structural models of flexible bodies. The active vibration control of the flexible multibody components is implemented using an asymmetric collocated piezoelectric sensor/actuator pair. An electromechanically coupled model is taken into account to properly consider the surface-bonded piezoelectric transducers and their effects on the time and spatial response of the flexible multibody components. The electromechanical effects are introduced in the flexible multibody equations of motion by the use of beam and plate/shell elements, developed to this purpose. A comparative study between the classical control strategies, constant gain and amplitude velocity feedback, and optimal control strategy, linear quadratic regulator (LQR), is performed in order to investigate their effectiveness to suppress vibrations in structures with piezoelectric sensing and actuating patches.

  2. Analysis of multi-scale spatial separation in a block-type thorium-loaded helium-cooled high-temperature reactor

    International Nuclear Information System (INIS)

    Huang, Jie; Ding, Ming

    2017-01-01

    Highlights: • Four-level of spatial separation is described in a block-type thorium-loaded HTR. • A traditional two-step calculation scheme is used to get the neutronic performance. • Fuel cycle cost is calculated by the levelised lifetime cost method. • Fuel cycle cost decreases with the increase of separation level or thorium content. • Effective enrichment basically determines the fuel cycle cost. - Abstract: With nuclear energy’s rapid development in recent years, supply of nuclear fuel has become increasingly important. Thorium has re-gained attention because of its abundant reserves and excellent physical properties. Compared to the homogeneous Th/U MOX fuel, separation of thorium and uranium in space is a better use of thorium. Therefore, this paper describes four-level spatial separation – no separation, tristructural-isotropic (TRISO) level, channel level and block level – in a block-type thorium-loaded helium-cooled high-temperature reactor (HTR). A traditional two-step calculation scheme, lattice calculation followed by core calculation, is used to get the neutronic performance of the equilibrium cycle, including uranium enrichment, mass of fuel, effective multiplication factor, and average conversion ratio. Based on these data, the fuel cycle cost of different-scale spatial separation can be calculated by the levelised lifetime cost method as a function of thorium content. As the separation level increases from no separation to channel level, the effective enrichment decreases 15% due to the increase of resonance escape probability. So there is a 13% drop for the fuel cycle cost. For TRISO-level separation, as the thorium content increases from 9 to 57%, the effective enrichment decreases 14% because of the superior breeding capacity of U-233. As a result, the fuel cycle cost also has about a 12% decrease. From the perspective of fuel cycle economics, channel-level separation with 60% thorium content is suggested.

  3. Computational Study of Separation Control Using ZNMF Devices: Flow Physics and Scaling Laws

    National Research Council Canada - National Science Library

    Mittal, Rajat

    2008-01-01

    The primary objective of the proposed research was to gain a fundamental understanding of strategies, mechanisms, and scaling laws for successful control of separation using zern-net mass-flux (ZNMF) actuators...

  4. A New Cluster Analysis-Marker-Controlled Watershed Method for Separating Particles of Granular Soils.

    Science.gov (United States)

    Alam, Md Ferdous; Haque, Asadul

    2017-10-18

    An accurate determination of particle-level fabric of granular soils from tomography data requires a maximum correct separation of particles. The popular marker-controlled watershed separation method is widely used to separate particles. However, the watershed method alone is not capable of producing the maximum separation of particles when subjected to boundary stresses leading to crushing of particles. In this paper, a new separation method, named as Monash Particle Separation Method (MPSM), has been introduced. The new method automatically determines the optimal contrast coefficient based on cluster evaluation framework to produce the maximum accurate separation outcomes. Finally, the particles which could not be separated by the optimal contrast coefficient were separated by integrating cuboid markers generated from the clustering by Gaussian mixture models into the routine watershed method. The MPSM was validated on a uniformly graded sand volume subjected to one-dimensional compression loading up to 32 MPa. It was demonstrated that the MPSM is capable of producing the best possible separation of particles required for the fabric analysis.

  5. Perceptual and Cognitive Load Interact to Control the Spatial Focus of Attention

    Science.gov (United States)

    Linnell, Karina J.; Caparos, Serge

    2011-01-01

    Caparos and Linnell (2009, 2010) used a variable-separation flanker paradigm to show that (a) when cognitive load is low, increasing perceptual load causes spatial attention to focus and (b) when perceptual load is high, decreasing cognitive load causes spatial attention to focus. Here, we tested whether the effects of perceptual and cognitive…

  6. The Dynamics of Controlled Flow Separation within a Diverter Duct Diffuser

    Science.gov (United States)

    Peterson, C. J.; Vukasinovic, B.; Glezer, A.

    2016-11-01

    The evolution and receptivity to fluidic actuation of the flow separation within a rectangular, constant-width, diffuser that is branched off of a primary channel is investigated experimentally at speeds up to M = 0.4. The coupling between the diffuser's adverse pressure gradient and the internal separation that constricts nearly half of the flow passage through the duct is controlled using a spanwise array of fluidic actuators on the surface upstream of the diffuser's inlet plane. The dynamics of the separating surface vorticity layer in the absence and presence of actuation are investigated using high-speed particle image velocimetry combined with surface pressure measurements and total pressure distributions at the primary channel's exit plane. It is shown that the actuation significantly alters the incipient dynamics of the separating vorticity layer as the characteristic cross stream scales of the boundary layer upstream of separation and of the ensuing vorticity concentrations within the separated flow increase progressively with actuation level. It is argued that the dissipative (high frequency) actuation alters the balance between large- and small-scale motions near separation by intensifying the large-scale motions and limiting the small-scale dynamics. Controlling separation within the diffuser duct also has a profound effect on the global flow. In the presence of actuation, the mass flow rate in the primary duct increases 10% while the fraction of the diverted mass flow rate in the diffuser increases by more than 45% at 0.7% actuation mass fraction. Supported by the Boeing Company.

  7. Fine particulate matter measurements in Swiss restaurants, cafés and bars: what is the effect of spatial separation between smoking and non-smoking areas?

    NARCIS (Netherlands)

    Huss, A.; Kooijman, C.; Breuer, M.; Bohler, P.; Zund, T.; Wenk, S.; Roosli, M.

    2010-01-01

    We performed 124 measurements of particulate matter (PM(2.5)) in 95 hospitality venues such as restaurants, bars, cafés, and a disco, which had differing smoking regulations. We evaluated the impact of spatial separation between smoking and non-smoking areas on mean PM(2.5) concentration, taking

  8. A fuzzy controller for the VASPS (Vertical Annular Separation and Pumping System) subsea separation and pumping system; Um controlador fuzzy para o sistema de separacao e bombeamento submarino - VASP (Vertical Annular Separation and Pumping System)

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Alex F.; Mendes, Jose Ricardo P.; Morooka, Celso K. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Petroleo; Estevam, Valdir [PETROBRAS, Rio de Janeiro, RJ (Brazil); Guilherme, Ivan R. [UNESP, Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas. Dept. de Estatistica, Matematica Aplicada e Computacao; Rigo, Jose Eduardo [Centro Federal de Educacao Tecnologica no Espirito Santo (CEFETES), Vitoria, ES (Brazil)

    2004-07-01

    In this paper the designs of a fuzzy controller for the VASPS (Vertical Annular Separation and Pumping System) liquid level and separation pressure control are presented, as well as a simulation of its work to evaluate the performance of the controller designed. The VASPS is a two-phase subsea separation and pumping system, which is made up of a separation vessel, where the mixture (liquid and gas) enters and suffers the separation process through three levels, the expansion chamber, the helix and the pool. The liquid inside the pool is taken to the platform using a pump that with a choke control the pool liquid level. The pool liquid level control is necessary because if the level exceeds the maximum value allowed, the liquid can invade the space occupied by the helix and hinder the separation process. An the other hand if the level is below the minimum allowed the pump can be damaged. The separation pressure control is important for operational security and efficiency issues, because when we keep the separation pressure near an optimum value we are maximizing its efficiency. With the controller and the simulator, many simulations of the work of system were made to get results that could be used to evaluate if the designed controller solved the problem and if its performance were satisfactory. After, a PID control system was designed to be used as comparison with the results obtained with the fuzzy controller, since the PID is widely used in the industrial environment. (author)

  9. Automatic Generation of Complex Spatial Trajectories of the UAV and Synthesis of Control

    Directory of Open Access Journals (Sweden)

    S. B. Tkachev

    2015-01-01

    function of energy. The full trajectory is assembled from the separated segments which have various types of parameterization.Programmed and nonlinear stabilizing controls are calculated for the designed spatial trajectory. The efficiency of the developed algorithms is shown using computer simulations.

  10. Using spatial context to support prospective memory in simulated air traffic control.

    Science.gov (United States)

    Loft, Shayne; Finnerty, Dannielle; Remington, Roger W

    2011-12-01

    The aim was to examine whether prospective memory error and response costs to ongoing tasks in an air traffic control simulation could be reduced by providing spatial context. Prospective memory refers to remembering to perform an intended action at an appropriate point in the future. Failures of prospective memory can occur in air traffic control. For this study, three conditions of participants performed an air traffic control task that required them to accept and hand off aircraft and to prevent conflicts. The prospective memory task required participants to remember to press an alternative key rather than the routine key when accepting target aircraft. A red line separated the display into upper and lower regions. Participants in the context condition were told that the prospective memory instruction would apply only to aircraft approaching from one region (upper or lower). Those in the standard condition were not provided this information. In the control condition, participants did not have to perform the prospective memory task. In the context condition, participants made fewer prospective memory errors than did those in the standard condition and made faster acceptance decisions for aircraft approaching from irrelevant compared with relevant regions. Costs to hand-off decision time were also reduced in the context condition. Spatial context provided no benefit to conflict detection. Participants could partially localize their allocation of attentional resources to the prospective memory task to relevant display regions. The findings are potentially applicable to air traffic control, whereby regularities in airspace structure and standard traffic flows allow controllers to anticipate the location of specific air traffic events.

  11. Parental Psychological Control and Dysfunctional Separation--Individuation: A Tale of Two Different Dynamics

    Science.gov (United States)

    Kins, Evie; Soenens, Bart; Beyers, Wim

    2012-01-01

    This study examined associations between psychologically controlling parenting and two possible manifestations of problematic separation--individuation (i.e., dysfunctional dependence and dysfunctional independence). To explain these associations, it has been argued that psychological control is an inherently independence-stifling parenting…

  12. A microfluidic chip for blood plasma separation using electro-osmotic flow control

    International Nuclear Information System (INIS)

    Jiang, Hai; Weng, Xuan; Chon, Chan Hee; Wu, Xudong; Li, Dongqing

    2011-01-01

    In this paper, a microfluidic-based chip with two straight microchannels and five branch microchannels was designed and tested to separate blood plasma from a small sample of fresh human blood. The electro-osmotic flow method was used to control the separation of blood plasma. Blood cell removal and blood plasma extraction were realized in experiments. The efficiency of extracting blood plasma can be as high as 26%

  13. Using resolvent analysis for the design of separation control on a NACA 0012 airfoil

    Science.gov (United States)

    Yeh, Chi-An; Taira, Kunihiko

    2017-11-01

    A combined effort based on large-eddy simulation and resolvent analysis on the separated flow over a NACA 0012 airfoil is conducted to design active flow control for suppression of separation. This study considers the the airfoil at 6 deg. angle-of-attack and Reynolds number of 23000. The response mode obtained from the resolvent analysis about the baseline turbulent mean flow reveals modal structures that can be categorized into three families when sweeping through the resonant frequency: (1) von Karman wake structure for low frequency; (2) Kelvin-Helmholtz structure in the separation bubble for high frequency; (3) blended structure of (1) and (2) for the intermediate frequency. Leveraging the insights from resolvent analysis, unsteady thermal actuation is introduced to the flow near the leading-edge to examine the use of the frequencies from three families for separation control in LES. As indicated by the resolvent response modes, we find that the use of intermediate frequencies are most effective in suppressing the flow separation, since the shear layer over the separation bubble and the wake are both receptive to the perturbation at the these frequencies. The resolvent-analysis-based control strategy achieves 35% drag reduction and 9% lift increase with effective frequency. This work was supported by Office of Naval Research (N00014-15-R-FO13) and Army Research Office (W911NF-14-1-0224).

  14. Effects of Wall-Normal and Angular Momentum Injections in Airfoil Separation Control

    Science.gov (United States)

    Munday, Phillip M.; Taira, Kunihiko

    2018-05-01

    The objective of this computational study is to quantify the influence of wall-normal and angular momentum injections in suppressing laminar flow separation over a canonical airfoil. Open-loop control of fully separated, incompressible flow over a NACA 0012 airfoil at $\\alpha = 9^\\circ$ and $Re = 23,000$ is examined with large-eddy simulations. This study independently introduces wall-normal momentum and angular momentum into the separated flow using swirling jets through model boundary conditions. The response of the flow field and the surface vorticity fluxes to various combinations of actuation inputs are examined in detail. It is observed that the addition of angular momentum input to wall-normal momentum injection enhances the suppression of flow separation. Lift enhancement and suppression of separation with the wall-normal and angular momentum inputs are characterized by modifying the standard definition of the coefficient of momentum. The effect of angular momentum is incorporated into the modified coefficient of momentum by introducing a characteristic swirling jet velocity based on the non-dimensional swirl number. With this single modified coefficient of momentum, we are able to categorize each controlled flow into separated, transitional, and attached flows.

  15. Movable shark scales act as a passive dynamic micro-roughness to control flow separation

    International Nuclear Information System (INIS)

    Lang, Amy W; Bradshaw, Michael T; Smith, Jonathon A; Wheelus, Jennifer N; Motta, Philip J; Habegger, Maria L; Hueter, Robert E

    2014-01-01

    Shark scales on fast-swimming sharks have been shown to be movable to angles in excess of 50°, and we hypothesize that this characteristic gives this shark skin a preferred flow direction. During the onset of separation, flow reversal is initiated close to the surface. However, the movable scales would be actuated by the reversed flow thereby causing a greater resistance to any further flow reversal and this mechanism would disrupt the process leading to eventual flow separation. Here we report for the first time experimental evidence of the separation control capability of real shark skin through water tunnel testing. Using skin samples from a shortfin mako Isurus oxyrinchus, we tested a pectoral fin and flank skin attached to a NACA 4412 hydrofoil and separation control was observed in the presence of movable shark scales under certain conditions in both cases. We hypothesize that the scales provide a passive, flow-actuated mechanism acting as a dynamic micro-roughness to control flow separation. (paper)

  16. Separating VNF and Network Control for Hardware‐Acceleration of SDN/NFV Architecture

    Directory of Open Access Journals (Sweden)

    Tong Duan

    2017-08-01

    Full Text Available A hardware‐acceleration architecture that separates virtual network functions (VNFs and network control (called HSN is proposed to solve the mismatch between the simple flow steering requirements and strong packet processing abilities of software‐defined networking (SDN forwarding elements (FEs in SDN/network function virtualization (NFV architecture, while improving the efficiency of NFV infrastructure and the performance of network‐intensive functions. HSN makes full use of FEs and accelerates VNFs through two mechanisms: (1 separation of traffic steering and packet processing in the FEs; (2 separation of SDN and NFV control in the FEs. Our HSN prototype, built on NetFPGA‐10G, demonstrates that the processing performance can be greatly improved with only a small modification of the traditional SDN/NFV architecture.

  17. Spatial controls of occurrence and spread of wildfires in the Missouri Ozark Highlands

    Science.gov (United States)

    Jian Yang; Hong S. He; Stephen R. Shifley

    2008-01-01

    Understanding spatial controls on wildfires is important when designing adaptive fire management plans and optimizing fuel treatment locations on a forest landscape. Previous research about this topic focused primarily on spatial controls for fire origin locations alone. Fire spread and behavior were largely overlooked. This paper contrasts the relative importance of...

  18. Separation Dynamics of Controlled Internal Flow in an Adverse Pressure Gradient

    Science.gov (United States)

    Peterson, C. J.; Vukasinovic, B.; Glezer, A.

    2017-11-01

    The effects of fluidic actuation on the dynamic evolution of aggressive internal flow separation is investigated at speeds up to M = 0.4 within a constant-width diffuser branching off of a primary flow duct. It is shown that a spanwise array of fluidic actuators upstream of the separation actively controls the flow constriction (and losses) within the diffuser and consequently the local pressure gradient at its entrance. The effectiveness of the actuation, as may be measured by the increased flow rate that is diverted through the diffuser, scales with its flow rate coefficient. In the presence of actuation (0.7% mass fraction), the mass flow rate in the primary duct increases by 10% while the fraction of the diverted mass flow rate in the diffuser increases by more than 45%. The flow dynamics near separation in the absence and presence of actuation are characterized using high speed particle image velocimetry and analyzed using proper orthogonal and spectral decompositions. In particular, the spectral contents of the incipient boundary layer separation are compared in the absence and presence of actuation with emphasis on the changes in local dynamics near separation as the characteristic cross stream scale of the boundary layer increases with separation delay.

  19. Use of reference materials for quality control of elemental analysis by neutron activation with radiochemical separation

    International Nuclear Information System (INIS)

    Woittiez, J.R.W.

    1990-01-01

    This paper describes the use of certified reference materials to monitor the long-term quality of radiochemical separations. The practical limitations which determine the actual design of the quality control are discussed. The hypothesis that the high yield of the radiochemical separation will be constant with time has been checked and validated for the elements Zn, Fe, Co, Cd, Mo and to a lesser extent for W and Th using NBS SRM 1577A, BCR CRM 274 and IAEA RM A-11. This validation could not be made for the elements Cr, Au, and Ag. Especially for Cr there is a serious lack of appropiate certified reference materials. (orig.)

  20. Chemical-Reaction-Controlled Phase Separated Drops: Formation, Size Selection, and Coarsening

    Science.gov (United States)

    Wurtz, Jean David; Lee, Chiu Fan

    2018-02-01

    Phase separation under nonequilibrium conditions is exploited by biological cells to organize their cytoplasm but remains poorly understood as a physical phenomenon. Here, we study a ternary fluid model in which phase-separating molecules can be converted into soluble molecules, and vice versa, via chemical reactions. We elucidate using analytical and simulation methods how drop size, formation, and coarsening can be controlled by the chemical reaction rates, and categorize the qualitative behavior of the system into distinct regimes. Ostwald ripening arrest occurs above critical reaction rates, demonstrating that this transition belongs entirely to the nonequilibrium regime. Our model is a minimal representation of the cell cytoplasm.

  1. Multi-interface Level Sensors and New Development in Monitoring and Control of Oil Separators

    Directory of Open Access Journals (Sweden)

    Wuqiang Yang

    2006-04-01

    Full Text Available In the oil industry, huge saving may be made if suitable multi-interface levelmeasurement systems are employed for effectively monitoring crude oil separators andefficient control of their operation. A number of techniques, e.g. externally mounteddisplacers, differential pressure transmitters and capacitance rod devices, have beendeveloped to measure the separation process with gas, oil, water and other components.Because of the unavailability of suitable multi-interface level measurement systems, oilseparators are currently operated by the trial-and-error approach. In this paper someconventional techniques, which have been used for level measurement in industry, and newdevelopment are discussed.

  2. Imaging the Spatial Distribution of Transport Currents and the Phenomenon of Nanoscale Phase Separation Phenomenon in CMR Materials

    National Research Council Canada - National Science Library

    Banerjee, Satyajit

    2007-01-01

    ... by transport currents sent through materials. Based on the above objective it was planned to apply this technique to investigate fundamental issues like magnetic phase separation in colossal magneto resistive materials as well as to investigate...

  3. Photoinduced charge separation in a colloidal system of exfoliated layered semiconductor controlled by coexisting aluminosilicate clay.

    Science.gov (United States)

    Nakato, Teruyuki; Yamada, Yoshimi; Miyamoto, Nobuyoshi

    2009-02-05

    We investigated photoinduced charge separation occurring in a multicomponent colloidal system composed of oxide nanosheets of photocatalytically active niobate and photochemically inert clay and electron accepting methylviologen dications (MV2+). The inorganic nanosheets were obtained by exfoliation of layered hexaniobate and hectorite clay. The niobate and clay nanosheets were spatially separated in the colloidally dispersed state, and the MV2+ molecules were selectively adsorbed on the clay platelets. UV irradiation of the colloids led to electron transfer from the niobate nanosheets to the MV2+ molecules adsorbed on clay. The photoinduced electron transfer produced methylviologen radical cations (MV*+), which was characterized by high yield and long lifetime. The yield and stability of the MV*+ species were found to depend strongly on the clay content of the colloid: from a few mol % to approximately 70 mol % of the yield and several tens of minutes to more than 40 h of the lifetime. The contents of the niobate nanosheets and MV2+ molecules and the aging of the colloid also affected the photoinduced charge separation. In the absence of MV2+ molecules in the colloid, UV irradiation induced electron accumulation in the niobate nanosheets. The stability of the electron-accumulated state also depended on the clay content. The variation in the photochemical behavior is discussed in relation to the viscosity of the colloid.

  4. Effects of boundary-layer separation controllers on a desktop fume hood.

    Science.gov (United States)

    Huang, Rong Fung; Chen, Jia-Kun; Hsu, Ching Min; Hung, Shuo-Fu

    2016-10-02

    A desktop fume hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surface, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surface on the leading edge of the work surface, and two small triangular plates on the upper left and right corners of the hood face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the hood face plane with a mannequin installed in front of the hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of the side plates and work surface, as well as the three-dimensional complex flows on the upper-left and -right corners of the hood face, were effectively alleviated by the boundary-layer separation controllers. The results of the tracer gas detection method with a mannequin standing in front of the hood showed that the leakage levels were negligibly small (≤0.003 ppm) at low face velocities (≥0.19 m/s).

  5. Separation flow control on a generic ground vehicle using steady microjet arrays

    Energy Technology Data Exchange (ETDEWEB)

    Aubrun, Sandrine; Kourta, Azeddine [Universite d' Orleans, Laboratoire PRISME, Orleans cedex (France); McNally, Jonathan; Alvi, Farrukh [Florida State University, FAMU-FSU College of Engineering, Tallahassee, FL (United States)

    2011-11-15

    A model of a generic vehicle shape, the Ahmed body with a 25 slant, is equipped with an array of blowing steady microjets 6 mm downstream of the separation line between the roof and the slanted rear window. The goal of the present study is to evaluate the effectiveness of this actuation method in reducing the aerodynamic drag, by reducing or suppressing the 3D closed separation bubble located on the slanted surface. The efficiency of this control approach is quantified with the help of aerodynamic load measurements. The changes in the flow field when control is applied are examined using PIV and wall pressure measurements and skin friction visualisations. By activating the steady microjet array, the drag coefficient was reduced by 9-14% and the lift coefficient up to 42%, depending on the Reynolds number. The strong modification of the flow topology under progressive flow control is particularly studied. (orig.)

  6. On controllability of an integrated bioreactor and periodically operated membrane separation process

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Jørgensen, Sten Bay; Jonsson, Gunnar Eigil

    the influence of membrane fouling. Previously, the REED and fermentation processes have been modeled and investigated separately (Prado- Rubio et al., 2011a; Boonmee, 2003). Additionally, a simple quasi-sequential strategy for integrated process design and control structure development has been proposed (Prado...... to understand the controlled operation of the integrated process, it is convenient to use a model based approach supported by experimental evidence. Recently, an integrated bioreactor and electrically driven membrane separation process (Reverse Electro- Enhanced Dialysis - REED) has been proposed as a method...... at a certain lactate concentration level. Hence, productivity can be enhanced by the in situ lactate removal from the cultivation broth during pH controlled fermentation. This can be done by means of ion exchange membranes and electrical potential gradients. The novelty of the integrated process lies...

  7. Active Flow Control and Global Stability Analysis of Separated Flow Over a NACA 0012 Airfoil

    Science.gov (United States)

    Munday, Phillip M.

    The objective of this computational study is to examine and quantify the influence of fundamental flow control inputs in suppressing flow separation over a canonical airfoil. Most flow control studies to this date have relied on the development of actuator technology, and described the control input based on specific actuators. Taking advantage of a computational framework, we generalize the inputs to fundamental perturbations without restricting inputs to a particular actuator. Utilizing this viewpoint, generalized control inputs aim to aid in the quantification and support the design of separation control techniques. This study in particular independently introduces wall-normal momentum and angular momentum to the separated flow using swirling jets through model boundary conditions. The response of the flow field and the surface vorticity fluxes to various combinations of actuation inputs are examined in detail. By closely studying different variables, the influence of the wall-normal and angular momentum injections on separated flow is identified. As an example, open-loop control of fully separated, incompressible flow over a NACA 0012 airfoil at alpha = 6° and 9° with Re = 23,000 is examined with large-eddy simulations. For the shallow angle of attack alpha = 6°, the small recirculation region is primarily affected by wall-normal momentum injection. For a larger separation region at alpha = 9°, it is observed that the addition of angular momentum input to wall-normal momentum injection enhances the suppression of flow separation. Reducing the size of the separated flow region significantly impacts the forces, and in particular reduces drag and increases lift on the airfoil. It was found that the influence of flow control on the small recirculation region (alpha = 6°) can be sufficiently quantified with the traditional coefficient of momentum. At alpha = 9°, the effects of wall-normal and angular momentum inputs are captured by modifying the standard

  8. Optical separation and controllable delivery of cells from particle and cell mixture

    Directory of Open Access Journals (Sweden)

    Li Yuchao

    2015-11-01

    Full Text Available Cell separation and delivery have recently gained significant attention in biological and biochemical studies. In thiswork, an optical method for separation and controllable delivery of cells by using an abruptly tapered fiber probe is reported. By launching a laser beam at the wavelength of 980 nm into the fiber, a mixture of cells with sizes of ~5 and ~3 μm and poly(methyl methacrylate particles with size of 5 μm are separated into three chains along the direction of propagation of light. The cell and particle chains are delivered in three dimensions over 600 μm distance. Experimental results are interpreted by numerical simulations. Optical forces and forward migration velocities of different particles and cells are calculated and discussed.

  9. Abiotic and biotic controls of spatial pattern at alpine treeline

    Science.gov (United States)

    Malanson, George P.; Xiao, Ningchuan; Alftine, K.J.; Bekker, Mathew; Butler, David R.; Brown, Daniel G.; Cairns, David M.; Fagre, Daniel; Walsh, Stephen J.

    2000-01-01

    At alpine treeline, trees and krummholz forms affect the environment in ways that increase their growth and reproduction. We assess the way in which these positive feedbacks combine in spatial patterns to alter the environment in the neighborhood of existing plants. The research is significant because areas of alpine tundra are susceptible to encroachment by woody species as climate changes. Moreover, understanding the general processes of plant invasion is important. The importance of spatial pattern has been recognized, but the spatial pattern of positive feedbacks per se has not been explored in depth. We present a linked set of models of vegetation change at an alpine forest-tundra ecotone. Our aim is to create models that are as simple as possible in order to test specific hypotheses. We present results from a model of the resource averaging hypothesis and the positive feedback switch hypothesis of treelines. We compare the patterns generated by the models to patterns observed in fine scale remotely sensed data.

  10. On the properties and mechanisms of microjet arrays in crossflow for the control of flow separation

    Science.gov (United States)

    Fernandez, Erik J.

    By utilizing passive and active methods of flow control, the aerodynamic performance of external and internal components can be greatly improved. Recently however, the benefits of applying active flow control methods to turbomachinery components for improved fuel efficiency, reduced engine size, and greater operational envelope has sparked a renewed interest in some of these flow control techniques. The more attractive of these, is active control in the form of jets in cross flow. With their ability to be turned on and off, as well as their negligible effect on drag when not being actuated, they are well suited for applications such as compressor and turbine blades, engine inlet diffusers, internal engine passages, and general external aerodynamics. This study consists of two parts. The first is the application of active control on a low-pressure turbine (LPT) cascade to determine the effectiveness of microjet actuators on flow separation at relatively low speeds. The second study, motivated by the first, involves a parametric study on a more canonical model to examine the effects of various microjet parameters on the efficacy of separation control and to provide a better understanding of the relevant flow physics governing this control approach. With data obtained from velocity measurements across the wide parametric range, correlations for the growth of the counter-rotating vortex pairs generated by these actuators are deduced. From the information and models obtained throughout the study, basic suggestions for microjet actuator design are presented.

  11. On the Active and Passive Flow Separation Control Techniques over Airfoils

    Science.gov (United States)

    Moghaddam, Tohid; Banazadeh Neishabouri, Nafiseh

    2017-10-01

    In the present work, recent advances in the field of the active and passive flow separation control, particularly blowing and suction flow control techniques, applied on the common airfoils are briefly reviewed. This broad research area has remained the point of interest for many years as it is applicable to various applications. The suction and blowing flow control methods, among other methods, are more technically feasible and market ready techniques. It is well established that the uniform and/or oscillatory blowing and suction flow control mechanisms significantly improve the lift-to-drag ratio, and further, postpone the boundary layer separation as well as the stall. The oscillatory blowing and suction flow control, however, is more efficient compared to the uniform one. A wide range of parameters is involved in controlling the behavior of a blowing and/or suction flow control, including the location, length, and angle of the jet slots. The oscillation range of the jet slot is another substantial parameter.

  12. Gravity packaging final waste recovery based on gravity separation and chemical imaging control.

    Science.gov (United States)

    Bonifazi, Giuseppe; Serranti, Silvia; Potenza, Fabio; Luciani, Valentina; Di Maio, Francesco

    2017-02-01

    Plastic polymers are characterized by a high calorific value. Post-consumer plastic waste can be thus considered, in many cases, as a typical secondary solid fuels according to the European Commission directive on End of Waste (EoW). In Europe the practice of incineration is considered one of the solutions for waste disposal waste, for energy recovery and, as a consequence, for the reduction of waste sent to landfill. A full characterization of these products represents the first step to profitably and correctly utilize them. Several techniques have been investigated in this paper in order to separate and characterize post-consumer plastic packaging waste fulfilling the previous goals, that is: gravity separation (i.e. Reflux Classifier), FT-IR spectroscopy, NIR HyperSpectralImaging (HSI) based techniques and calorimetric test. The study demonstrated as the proposed separation technique and the HyperSpectral NIR Imaging approach allow to separate and recognize the different polymers (i.e. PolyVinyl Chloride (PVC), PolyStyrene (PS), PolyEthylene (PE), PoliEtilene Tereftalato (PET), PolyPropylene (PP)) in order to maximize the removal of the PVC fraction from plastic waste and to perform the full quality control of the resulting products, can be profitably utilized to set up analytical/control strategies finalized to obtain a low content of PVC in the final Solid Recovered Fuel (SRF), thus enhancing SRF quality, increasing its value and reducing the "final waste". Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Controlling for unmeasured confounding and spatial misalignment in long?term air pollution and health studies

    OpenAIRE

    Lee, Duncan; Sarran, Christophe

    2015-01-01

    The health impact of long?term exposure to air pollution is now routinely estimated using spatial ecological studies, owing to the recent widespread availability of spatial referenced pollution and disease data. However, this areal unit study design presents a number of statistical challenges, which if ignored have the potential to bias the estimated pollution?health relationship. One such challenge is how to control for the spatial autocorrelation present in the data after accounting for the...

  14. Spatial processes decouple management from objectives in a heterogeneous landscape: predator control as a case study.

    Science.gov (United States)

    Mahoney, Peter J; Young, Julie K; Hersey, Kent R; Larsen, Randy T; McMillan, Brock R; Stoner, David C

    2018-04-01

    Predator control is often implemented with the intent of disrupting top-down regulation in sensitive prey populations. However, ambiguity surrounding the efficacy of predator management, as well as the strength of top-down effects of predators in general, is often exacerbated by the spatially implicit analytical approaches used in assessing data with explicit spatial structure. Here, we highlight the importance of considering spatial context in the case of a predator control study in south-central Utah. We assessed the spatial match between aerial removal risk in coyotes (Canis latrans) and mule deer (Odocoileus hemionus) resource selection during parturition using a spatially explicit, multi-level Bayesian model. With our model, we were able to evaluate spatial congruence between management action (i.e., coyote removal) and objective (i.e., parturient deer site selection) at two distinct scales: the level of the management unit and the individual coyote removal. In the case of the former, our results indicated substantial spatial heterogeneity in expected congruence between removal risk and parturient deer site selection across large areas, and is a reflection of logistical constraints acting on the management strategy and differences in space use between the two species. At the level of the individual removal, we demonstrated that the potential management benefits of a removed coyote were highly variable across all individuals removed and in many cases, spatially distinct from parturient deer resource selection. Our methods and results provide a means of evaluating where we might anticipate an impact of predator control, while emphasizing the need to weight individual removals based on spatial proximity to management objectives in any assessment of large-scale predator control. Although we highlight the importance of spatial context in assessments of predator control strategy, we believe our methods are readily generalizable in any management or large

  15. Modern approaches of control of spatial organization of schoolchildren body in the process of physical education

    Directory of Open Access Journals (Sweden)

    Bondar O.M.

    2012-08-01

    Full Text Available Technology of control of spatial organization of body of schoolboys is developed. Technology includes the diagnostic, informative and practical stages. Research is oriented to the schoolchildren 7-16 years. The diagnostic stage is supposed by a complex inspection and express control of spatial organization of bodies. The informative stage includes computer treatment of research results. The practical stage consists of development of recommendations on the correction of indexes of spatial organization of body of schoolchildren. Logical component allows to expose the level of knowledge of parents and teachers of physical culture about control of spatial organization of body of schoolchildren. The developed technology allows to carry out timely diagnostics of violations of spatial organization of body of schoolchildren and estimate adequacy of pedagogical influences.

  16. Aspects regarding at 13C isotope separation column control using Petri nets system

    International Nuclear Information System (INIS)

    Boca, M L; Ciortea, M E

    2015-01-01

    This paper is intended to show that Petri nets can be also applicable in the chemical industry. It used linear programming, modeling underlying Petri nets, especially discrete event systems for isotopic separation, the purpose of considering and control events in real-time through graphical representations. In this paper it is simulate the control of 13 C Isotope Separation column using Petri nets. The major problem with 13 C comes from the difficulty of obtaining it and raising its natural fraction. Carbon isotopes can be obtained using many methods, one of them being the cryogenic distillation of carbon monoxide. Some few aspects regarding operating conditions and the construction of such cryogenic plants are known today, and even less information are available as far as the separation process modeling and control are concerned. In fact, the efficient control of the carbon monoxide distillation process represents a necessity for large-scale 13 C production. Referring to a classic distillation process, some models for carbon isotope separation have been proposed, some based on mass, component and energy balance equations, some on the nonlinear wave theory or the Cohen equations. For modeling the system it was used Petri nets because in this case it is deal with discrete event systems. In use of the non-timed and with auxiliary times Petri model, the transport stream was divided into sections and these sections will be analyzed successively. Because of the complexity of the system and the large amount of calculations required it was not possible to analyze the system as a unitary whole. A first attempt to model the system as a unitary whole led to the blocking of the model during simulation, because of the large processing times. (paper)

  17. Parametric analyses for synthetic jet control on separation and stall over rotor airfoil

    Directory of Open Access Journals (Sweden)

    Zhao Guoqing

    2014-10-01

    Full Text Available Numerical simulations are performed to investigate the effects of synthetic jet control on separation and stall over rotor airfoils. The preconditioned and unsteady Reynolds-averaged Navier–Stokes equations coupled with a k − ω shear stream transport turbulence model are employed to accomplish the flowfield simulation of rotor airfoils under jet control. Additionally, a velocity boundary condition modeled by a sinusoidal function is developed to fulfill the perturbation effect of periodic jets. The validity of the present CFD procedure is evaluated by the simulated results of an isolated synthetic jet and the jet control case for airfoil NACA0015. Then, parametric analyses are conducted specifically for an OA213 rotor airfoil to investigate the effects of jet parameters (forcing frequency, jet location and momentum coefficient, jet direction, and distribution of jet arrays on the control effect of the aerodynamic characteristics of a rotor airfoil. Preliminary results indicate that the efficiency of jet control can be improved with specific frequencies (the best lift-drag ratio at F+ = 2.0 and jet angles (40° or 75° when the jets are located near the separation point of the rotor airfoil. Furthermore, as a result of a suitable combination of jet arrays, the lift coefficient of the airfoil can be improved by nearly 100%, and the corresponding drag coefficient decreased by 26.5% in comparison with the single point control case.

  18. Controller Development for a Separate Meter-In Separate Meter-Out Fluid Power Valve for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Brian

    machinery. For a rotary motion electrical motors controlled by using power electronics is a competing technology because of their high energy efficiency. Additionally, the energy density of electrical devices is still increasing. In fluid power systems where more consumers (cylinders or motors) are supplied...... relative stability due to design restrictions. Robust controllers for the valve using the remaining pilot control method are developed. The robustness is evaluated by simulations and afterwards the controllers are tested experimentally. A model of a hydraulic actuator system with a flexible load structure...

  19. Controlled power supply for isotopes separator; Alimentations regulees pour separateur d'isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Lavaitte, A; Pottier, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1953-07-01

    This equipment is destined to equip the separator of isotopes who is the subject of the CEA report n 138. It includes: - a controlled power supply in voltage. - a controlled power supply in current. The spectra of fluctuations of these assembly is different in the two cases. (authors) [French] Cet equipement est destine a equiper le separateur d'isotopes qui fait l'objet du rapport C.E.A. n 138. Il comprend: - une alimentation regulee en tension. - une alimentation regulee en courant. Le spectre de fluctuations de ces ensembles est different dans les deux cas. (auteurs)

  20. Transitioning Resolution Responsibility between the Controller and Automation Team in Simulated NextGen Separation Assurance

    Science.gov (United States)

    Cabrall, C.; Gomez, A.; Homola, J.; Hunt, S..; Martin, L.; Merccer, J.; Prevott, T.

    2013-01-01

    As part of an ongoing research effort on separation assurance and functional allocation in NextGen, a controller- in-the-loop study with ground-based automation was conducted at NASA Ames' Airspace Operations Laboratory in August 2012 to investigate the potential impact of introducing self-separating aircraft in progressively advanced NextGen timeframes. From this larger study, the current exploratory analysis of controller-automation interaction styles focuses on the last and most far-term time frame. Measurements were recorded that firstly verified the continued operational validity of this iteration of the ground-based functional allocation automation concept in forecast traffic densities up to 2x that of current day high altitude en-route sectors. Additionally, with greater levels of fully automated conflict detection and resolution as well as the introduction of intervention functionality, objective and subjective analyses showed a range of passive to active controller- automation interaction styles between the participants. Not only did the controllers work with the automation to meet their safety and capacity goals in the simulated future NextGen timeframe, they did so in different ways and with different attitudes of trust/use of the automation. Taken as a whole, the results showed that the prototyped controller-automation functional allocation framework was very flexible and successful overall.

  1. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

    Directory of Open Access Journals (Sweden)

    D. K. Hare

    2017-11-01

    Full Text Available Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns

  2. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

    Science.gov (United States)

    Hare, Danielle K.; Boutt, David F.; Clement, William P.; Hatch, Christine E.; Davenport, Glorianna; Hackman, Alex

    2017-11-01

    Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns may allow resource

  3. Selective alteration of adult hippocampal neurogenesis and impaired spatial pattern separation performance in the RSK2-deficient mouse model of Coffin-Lowry syndrome.

    Science.gov (United States)

    Castillon, Charlotte; Lunion, Steeve; Desvignes, Nathalie; Hanauer, André; Laroche, Serge; Poirier, Roseline

    2018-07-01

    Adult neurogenesis is involved in certain hippocampus-dependent cognitive functions and is linked to psychiatric diseases including intellectual disabilities. The Coffin-Lowry syndrome (CLS) is a developmental disorder caused by mutations in the Rsk2 gene and characterized by intellectual disabilities associated with growth retardation. How RSK2-deficiency leads to cognitive dysfunctions in CLS is however poorly understood. Here, using Rsk2 Knock-Out mice, we characterized the impact of RSK2 deficiency on adult hippocampal neurogenesis in vivo. We report that the absence of RSK2 does not affect basal proliferation, differentiation and survival of dentate gyrus adult-born neurons but alters the maturation progression of young immature newborn neurons. Moreover, when RSK2-deficient mice were submitted to spatial learning, in contrast to wild-type mice, proliferation of adult generated neurons was decreased and no pro-survival effect of learning was observed. Thus, learning failed to recruit a selective population of young newborn neurons in association with deficient long-term memory recall. Given the proposed role of the dentate gyrus and of adult-generated newborn neurons in hippocampal-dependent pattern separation function, we explored this function in a delayed non-matching to place task and in an object-place pattern separation task and report severe deficits in spatial pattern separation in Rsk2-KO mice. Together, this study reveals a previously unknown role for RSK2 in the early stages of maturation and learning-dependent involvement of adult-born dentate gyrus neurons. These alterations associated with a deficit in the ability of RSK2-deficient mice to finely discriminate relatively similar spatial configurations, may contribute to cognitive dysfunction in CLS. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Professional mathematicians differ from controls in their spatial-numerical associations.

    Science.gov (United States)

    Cipora, Krzysztof; Hohol, Mateusz; Nuerk, Hans-Christoph; Willmes, Klaus; Brożek, Bartosz; Kucharzyk, Bartłomiej; Nęcka, Edward

    2016-07-01

    While mathematically impaired individuals have been shown to have deficits in all kinds of basic numerical representations, among them spatial-numerical associations, little is known about individuals with exceptionally high math expertise. They might have a more abstract magnitude representation or more flexible spatial associations, so that no automatic left/small and right/large spatial-numerical association is elicited. To pursue this question, we examined the Spatial Numerical Association of Response Codes (SNARC) effect in professional mathematicians which was compared to two control groups: Professionals who use advanced math in their work but are not mathematicians (mostly engineers), and matched controls. Contrarily to both control groups, Mathematicians did not reveal a SNARC effect. The group differences could not be accounted for by differences in mean response speed, response variance or intelligence or a general tendency not to show spatial-numerical associations. We propose that professional mathematicians possess more abstract and/or spatially very flexible numerical representations and therefore do not exhibit or do have a largely reduced default left-to-right spatial-numerical orientation as indexed by the SNARC effect, but we also discuss other possible accounts. We argue that this comparison with professional mathematicians also tells us about the nature of spatial-numerical associations in persons with much less mathematical expertise or knowledge.

  5. Positive Analysis of Invasive Species Control as a Dynamic Spatial Process

    OpenAIRE

    Buyuktahtakin, Esra; Feng, Zhuo; Olsson, Aaryn; Frisvold, George B.; Szidarovszky, Ferenc

    2010-01-01

    This paper models control of invasive buffelgrass (Pennisetum ciliare), a fire-prone African bunchgrass spreading rapidly across the southern Arizona desert as a spatial dynamic process. Buffelgrass spreads over a gridded landscape. Weed carrying capacity, treatment costs, and damages vary over grid cells. Damage from buffelgrass depends on its spatial distribution in relation to valued resources. We conduct positive analysis of recommended heuristic strategies for buffelgrass control, evalua...

  6. Scaling impacts on environmental controls and spatial heterogeneity of soil organic carbon stocks

    Science.gov (United States)

    Mishra, U.; Riley, W. J.

    2015-07-01

    The spatial heterogeneity of land surfaces affects energy, moisture, and greenhouse gas exchanges with the atmosphere. However, representing the heterogeneity of terrestrial hydrological and biogeochemical processes in Earth system models (ESMs) remains a critical scientific challenge. We report the impact of spatial scaling on environmental controls, spatial structure, and statistical properties of soil organic carbon (SOC) stocks across the US state of Alaska. We used soil profile observations and environmental factors such as topography, climate, land cover types, and surficial geology to predict the SOC stocks at a 50 m spatial scale. These spatially heterogeneous estimates provide a data set with reasonable fidelity to the observations at a sufficiently high resolution to examine the environmental controls on the spatial structure of SOC stocks. We upscaled both the predicted SOC stocks and environmental variables from finer to coarser spatial scales (s = 100, 200, and 500 m and 1, 2, 5, and 10 km) and generated various statistical properties of SOC stock estimates. We found different environmental factors to be statistically significant predictors at different spatial scales. Only elevation, temperature, potential evapotranspiration, and scrub land cover types were significant predictors at all scales. The strengths of control (the median value of geographically weighted regression coefficients) of these four environmental variables on SOC stocks decreased with increasing scale and were accurately represented using mathematical functions (R2 = 0.83-0.97). The spatial structure of SOC stocks across Alaska changed with spatial scale. Although the variance (sill) and unstructured variability (nugget) of the calculated variograms of SOC stocks decreased exponentially with scale, the correlation length (range) remained relatively constant across scale. The variance of predicted SOC stocks decreased with spatial scale over the range of 50 m to ~ 500 m, and remained

  7. Simulation of body force field effects on airfoil separation control and optimization of plasma actuator

    International Nuclear Information System (INIS)

    Abdoli, A; Mirzaee, I; Purmahmod, N; Anvari, A

    2008-01-01

    Among all active flow control methods, EHD, MHD and EMHD are the only methods which operate on the basis of body force induction on flow field. The EHD plasma actuator is the proper method which has been used in various flow control applications recently. In this paper, the effects of different body force fields on different domains have been studied for separation control on NACA 0021 and the results have been discussed. The airflow velocity has been assumed to be 35 m s -1 at a post-stall angle of attack of 23 deg. Three different domains have been used around the airfoil to investigate body forces with different strengths and directions and those which give the best result in separation control have been obtained for each domain. It has been shown that the results could be used for optimizing the plasma actuator by manipulating its electrode configuration. Two non-dimensional numbers, A b and D c , have been obtained and validated by different applied body forces. These numbers have been defined for plasma actuators to show their efficiency in different applications

  8. Simulation of body force field effects on airfoil separation control and optimization of plasma actuator

    Energy Technology Data Exchange (ETDEWEB)

    Abdoli, A; Mirzaee, I; Purmahmod, N [Faculty of Engineering, Urmia University, Urmia (Iran, Islamic Republic of); Anvari, A [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: ab.abdoli@gmail.com

    2008-09-07

    Among all active flow control methods, EHD, MHD and EMHD are the only methods which operate on the basis of body force induction on flow field. The EHD plasma actuator is the proper method which has been used in various flow control applications recently. In this paper, the effects of different body force fields on different domains have been studied for separation control on NACA 0021 and the results have been discussed. The airflow velocity has been assumed to be 35 m s{sup -1} at a post-stall angle of attack of 23 deg. Three different domains have been used around the airfoil to investigate body forces with different strengths and directions and those which give the best result in separation control have been obtained for each domain. It has been shown that the results could be used for optimizing the plasma actuator by manipulating its electrode configuration. Two non-dimensional numbers, A{sub b} and D{sub c}, have been obtained and validated by different applied body forces. These numbers have been defined for plasma actuators to show their efficiency in different applications.

  9. Separate and unequal: the influence of neighborhood and school characteristics on spatial proximity between fast food and schools.

    Science.gov (United States)

    Kwate, Naa Oyo A; Loh, Ji Meng

    2010-08-01

    Social science and health literature have identified residential segregation as a critical factor in exposure to health-related resources, including food environments. Differential spatial patterning of food environments surrounding schools has significant import for youth. We examined whether fast food restaurants clustered around schools in New York City, and whether any observed clustering varied as a function of school type, school racial demographics, and area racial and socioeconomic demographics. We geocoded fast food locations from 2006 (n=817) and schools from 2004-2005 (n=2096; public and private, elementary and secondary) in the five boroughs of New York City. A point process model (inhomogeneous cross-K function) examined spatial clustering. A minimum of 25% of schools had a fast food restaurant within 400 m. High schools had higher fast food clustering than elementary schools. Public elementary and high schools with large proportions of Black students or in block groups with large proportions of Black residents had higher clustering than White counterparts. Finally, public high schools had higher clustering than private counterparts, with 1.25 to 2 times as many restaurants than expected by chance. The results suggest that the geography of opportunity as it relates to school food environments is unequal in New York City. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Spatial control of direct chemical vapor deposition of graphene on silicon dioxide by directional copper dewetting

    NARCIS (Netherlands)

    van den Beld, Wesley Theodorus Eduardus; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    In this paper we present a method for the spatial control of direct graphene synthesis onto silicon dioxide by controlled dewetting. The dewetting process is controlled through a combination of using a grooved substrate and conducting copper deposition at an angle. The substrate is then treated

  11. Cluster-based control of a separating flow over a smoothly contoured ramp

    Science.gov (United States)

    Kaiser, Eurika; Noack, Bernd R.; Spohn, Andreas; Cattafesta, Louis N.; Morzyński, Marek

    2017-12-01

    The ability to manipulate and control fluid flows is of great importance in many scientific and engineering applications. The proposed closed-loop control framework addresses a key issue of model-based control: The actuation effect often results from slow dynamics of strongly nonlinear interactions which the flow reveals at timescales much longer than the prediction horizon of any model. Hence, we employ a probabilistic approach based on a cluster-based discretization of the Liouville equation for the evolution of the probability distribution. The proposed methodology frames high-dimensional, nonlinear dynamics into low-dimensional, probabilistic, linear dynamics which considerably simplifies the optimal control problem while preserving nonlinear actuation mechanisms. The data-driven approach builds upon a state space discretization using a clustering algorithm which groups kinematically similar flow states into a low number of clusters. The temporal evolution of the probability distribution on this set of clusters is then described by a control-dependent Markov model. This Markov model can be used as predictor for the ergodic probability distribution for a particular control law. This probability distribution approximates the long-term behavior of the original system on which basis the optimal control law is determined. We examine how the approach can be used to improve the open-loop actuation in a separating flow dominated by Kelvin-Helmholtz shedding. For this purpose, the feature space, in which the model is learned, and the admissible control inputs are tailored to strongly oscillatory flows.

  12. Thermodynamic stability of driven open systems and control of phase separation by electro-autocatalysis.

    Science.gov (United States)

    Bazant, Martin Z

    2017-07-01

    Motivated by the possibility of electrochemical control of phase separation, a variational theory of thermodynamic stability is developed for driven reactive mixtures, based on a nonlinear generalization of the Cahn-Hilliard and Allen-Cahn equations. The Glansdorff-Prigogine stability criterion is extended for driving chemical work, based on variations of nonequilibrium Gibbs free energy. Linear stability is generally determined by the competition of chemical diffusion and driven autocatalysis. Novel features arise for electrochemical systems, related to controlled total current (galvanostatic operation), concentration-dependent exchange current (Butler-Volmer kinetics), and negative differential reaction resistance (Marcus kinetics). The theory shows how spinodal decomposition can be controlled by solo-autocatalytic charge transfer, with only a single faradaic reaction. Experimental evidence is presented for intercalation and electrodeposition in rechargeable batteries, and further applications are discussed in solid state ionics, electrovariable optics, electrochemical precipitation, and biological pattern formation.

  13. Generating spatial and nonspatial attentional control: an ERP study

    NARCIS (Netherlands)

    Slagter, H.A.; Kok, A.; Mol, N.; Talsma, D.; Kenemans, J.L.

    2005-01-01

    The present study used event-related potentials and dipole source modeling to investigate dimension specificity in attentional control. Subjects performed cued attention tasks in which the task-relevant information (a) was always the same, (b) varied between features within the same dimension, or

  14. Control processes in visual spatial attention : an electrophysiological investigation

    NARCIS (Netherlands)

    Velzen, José Lucia van

    2005-01-01

    ln recent years the there has been growing interest in the topic of attentional control in the field of cognitive neuroscience. The first chapter of this thesis introduces the relevant theoretical concepts in the study of selective attention and gives an overview of what has become known from

  15. Nanoscale tissue engineering: spatial control over cell-materials interactions

    International Nuclear Information System (INIS)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali; Jabbari, Esmaiel

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  16. Control over phase separation and nucleation using a laser-tweezing potential

    Science.gov (United States)

    Walton, Finlay; Wynne, Klaas

    2018-05-01

    Control over the nucleation of new phases is highly desirable but elusive. Even though there is a long history of crystallization engineering by varying physicochemical parameters, controlling which polymorph crystallizes or whether a molecule crystallizes or forms an amorphous precipitate is still a poorly understood practice. Although there are now numerous examples of control using laser-induced nucleation, the absence of physical understanding is preventing progress. Here we show that the proximity of a liquid-liquid critical point or the corresponding binodal line can be used by a laser-tweezing potential to induce concentration gradients. A simple theoretical model shows that the stored electromagnetic energy of the laser beam produces a free-energy potential that forces phase separation or triggers the nucleation of a new phase. Experiments in a liquid mixture using a low-power laser diode confirm the effect. Phase separation and nucleation using a laser-tweezing potential explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter.

  17. Investigating the Complexity of Transitioning Separation Assurance Tools into NextGen Air Traffic Control

    Science.gov (United States)

    Gomez, Ashley Nicole; Martin, Lynne Hazel; Homola, Jeffrey; Morey, Susan; Cabrall, Christopher; Mercer, Joey; Prevot, Thomas

    2013-01-01

    In a study, that introduced ground-based separation assurance automation through a series of envisioned transitional phases of concept maturity, it was found that subjective responses to scales of workload, situation awareness, and acceptability in a post run questionnaire revealed as-predicted results for three of the four study conditions but not for the third, Moderate condition. The trend continued for losses of separation (LOS) where the number of LOS events were far greater than expected in the Moderate condition. To offer an account of why the Moderate condition was perceived to be more difficult to manage than predicted, researchers examined the increase in amount and complexity of traffic, increase in communication load, and increased complexities as a result of the simulation's mix of aircraft equipage. Further analysis compared the tools presented through the phases, finding that controllers took advantage of the informational properties of the tools presented but shied away from using their decision support capabilities. Taking into account similar findings from other studies, it is suggested that the Moderate condition represented the first step into a "shared control" environment, which requires the controller to use the automation as a decision making partner rather than just a provider of information. Viewed in this light, the combination of tools offered in the Moderate condition was reviewed and some tradeoffs that may offset the identified complexities were suggested.

  18. Active flow control of the laminar separation bubble on a plunging airfoil near stall

    Science.gov (United States)

    Pande, Arth; Agate, Mark; Little, Jesse; Fasel, Hermann

    2017-11-01

    The effects of small amplitude (A/c = 0.048) high frequency (πfc/U∞ = 0.70) plunging motion on the X-56A airfoil are examined experimentally at Re = 200,000 for 12° angle of attack (CL,MAX = 12.25°) . The purpose of this research is to study the aerodynamic influence of structural motion when the wing is vibrating close to its eigenfrequency near static stall. Specific focus is placed on the laminar separation bubble (LSB) near the leading edge and its control via plasma actuation. In the baseline case, the leading edge bubble bursts during the oscillation cycle causing moment stall. A collaborative computational effort has shown that small amplitude forcing at a frequency that is most amplified by the primary instability of the LSB (FLSB+= 1, Fc+= 52) generates coherent spanwise vortices that entrain freestream momentum, thus reducing separation all while maintaining a laminar flow state. Results (PIV and surface pressure) indicate that a similar control mechanism is effective in the experiments. This is significant given the existence of freestream turbulence in the wind tunnel which has been shown to limit the efficacy of this active flow control technique in a model problem using Direct Numerical Simulation. The implications of these results are discussed.

  19. Factors Controlling Redox Speciation of Plutonium and Neptunium in Extraction Separation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Paulenova, Alena [Principal Investigator; Vandegrift, III, George F. [Collaborator

    2013-09-24

    The objective of the project was to examine the factors controlling redox speciation of plutonium and neptunium in UREX+ extraction in terms of redox potentials, redox mechanism, kinetics and thermodynamics. Researchers employed redox-speciation extractions schemes in parallel to the spectroscopic experiments. The resulting distribution of redox species w studied uring spectroscopic, electrochemical, and spectro-electrochemical methods. This work reulted in collection of data on redox stability and distribution of redox couples in the nitric acid/nitrate electrolyte and the development of redox buffers to stabilize the desired oxidation state of separated radionuclides. The effects of temperature and concentrations on the redox behavior of neptunium were evaluated.

  20. Excitons formed from spatially separated electrons and holes in Ge/Si geterostructures with Ge quantum dots

    International Nuclear Information System (INIS)

    Pokutnyj, S.I.

    2016-01-01

    The effect of a significant increase in the exciton binding energy of space-separated electrons and holes (hole moves in the volume of the quantum dot, and the electron is localized on a spherical surface section quantum dot-matrix) in nanosystems containing germanium quantum dots grown in a matrix of silicon by compared with the binding energy of an exciton in a silicon single crystal. It was found that in such nanosystems in the conduction band silicon matrix is first a zone of states of electron-hole pairs, which with increasing radius of the quantum dot becomes a zone of exciton states, located in the band gap of silicon matrix. It is shown that the mechanism of light absorption in nanosystems due to transitions between quantum-electron levels of the electron-hole pairs, as well as the electron transitions between quantum-exciton levels.

  1. Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control.

    Science.gov (United States)

    Nakayama, Daichi; Mok, Yeongbong; Noh, Minwoo; Park, Jeongseon; Kang, Sunyoung; Lee, Yan

    2014-03-21

    Lower critical solution temperature (LCST) phase transition of glycol ether (GE)-water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) n-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH-water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH-water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH-water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH-water mixture, and the osmotic flux between the DEH-water mixture and salt solutions were carefully analysed for FO desalination. The liquid-liquid phase separation of the GE-water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.

  2. A strain-controlled C2N monolayer membrane for gas separation in PEMFC application

    Science.gov (United States)

    Deng, Shengwei; Hu, Hui; Zhuang, Guilin; Zhong, Xing; Wang, Jianguo

    2018-05-01

    Ultrathin membranes with controllable pore sizes have great potential to realize high-selectivity gas separation at low energy cost, especially for those mixtures with narrow size distributions. Using a combination of van der Waals-corrected density functional theory (DFT) calculations and molecular dynamics (MD) simulation, we examine the separation ability of biaxial stretched monolayer C2N nanosheets which is applied to the O2 separation from CO/CO2/O2 mixtures in the cathode of proton exchange membrane fuel cells (PEMFC). The DFT calculations show that the diffusion energy barrier for molecules passing through the membrane followed by CO, CO2 and O2 in descending order, and an overall decrease of energy barriers due to the widen the pore size is observed with the increase of applied strains. Furthermore, MD results show that the nanosheet can effectively purify O2 from CO2 and CO with a strain from 8% to 10%. It confirms that the selectivity is determined by the electronic structure related interaction in addition to the kinetic diameter of individual molecules. The O2 permeability is improved progressively with further increase of strain, and small amount of CO2 begins to permeate through the nanosheet at relatively large strain, while the excellent CO isolation is not compromised until the theoretical maximum strain.

  3. Comparison of the efficacy of ibuprofen and belladonna in the control of orthodontic separator pain

    Directory of Open Access Journals (Sweden)

    Harshal Ashok Patil

    2018-01-01

    Full Text Available Background: The purpose of this study was to compare the efficacy of ibuprofen and Belladonna in the control of orthodontic pain and to ascertain the pain relief by Belladonna in comparison with ibuprofen during orthodontic separation. Materials and Methods: Patients, between 20 and 35 years of age, 51 females and 21 males, were included in this study. Patients were randomly divided into two groups; one group was assigned to ibuprofen 400 mg and second group was allocated to Belladonna 6C group. Patients were given two doses of medication of their respective groups, 1 h before placement of elastomeric separators (Ormco Separators, Ormco Corporation, CA, USA which was administered in the department and one dose 6 h after the placement. Pain scores recorded on visual analogue scale (VAS. VAS was a 10 cm scale with millimetre calibration to record their pain at the following intervals, 2 h after placement, 6 h after placement, bedtime, day 1 morning, day 2 morning, day 3 morning and day 5 morning. Results: Post hoc comparisons indicated that there was no difference between the two groups at 2 h (P = 0.77, 6 h (0.073, 1 day (P = 0.120, 2 days (P = 0.283, 3 days (P = 0.363, 5 days (P = 0.622 and 7 days. Conclusion: Ibuprofen and Belladonna 6C are effective and provide adequate analgesia with no statistically significant difference. Lack of adverse effects with Belladonna 6C makes it an effective and viable alternative.

  4. Mind the Gap: The Effects of Temporal and Spatial Separation in Localization of Dual Touches on the Hand

    Directory of Open Access Journals (Sweden)

    Renata Sadibolova

    2018-02-01

    Full Text Available In this study, we aimed to relate the findings from two predominantly separate streams of literature, one reporting on the localization of single touches on the skin, and the other on the distance perception of dual touches. Participants were touched with two points, delivered either simultaneously or separated by a short delay to various locations on their left hand dorsum. They then indicated on a size-matched hand silhouette the perceived locations of tactile stimuli. We quantified the deviations between the actual stimulus grid and the corresponding perceptual map which was constructed from the perceived tactile locations, and we calculated the precision of tactile localization (i.e., the variability across localization attempts. The evidence showed that the dual touches, akin to single touch stimulations, were mislocalized distally and that their variable localization error was reduced near joints, particularly near knuckles. However, contrary to single-touch localization literature, we observed for the dual touches to be mislocalized towards the ulnar side of the hand, particularly when they were presented sequentially. Further, the touches presented in a sequential order were slightly “repelled” from each other and their perceived distance increased, while the simultaneous tactile pairs were localized closer to each other and their distance was compressed. Whereas the sequential touches may have been localized with reference to the body, the compression of tactile perceptual space for simultaneous touches was related in the previous literature to signal summation and inhibition and the low-level factors, including the innervation density and properties of receptive fields (RFs of somatosensory neurons.

  5. Mind the Gap: The Effects of Temporal and Spatial Separation in Localization of Dual Touches on the Hand.

    Science.gov (United States)

    Sadibolova, Renata; Tamè, Luigi; Walsh, Eamonn; Longo, Matthew R

    2018-01-01

    In this study, we aimed to relate the findings from two predominantly separate streams of literature, one reporting on the localization of single touches on the skin, and the other on the distance perception of dual touches. Participants were touched with two points, delivered either simultaneously or separated by a short delay to various locations on their left hand dorsum. They then indicated on a size-matched hand silhouette the perceived locations of tactile stimuli. We quantified the deviations between the actual stimulus grid and the corresponding perceptual map which was constructed from the perceived tactile locations, and we calculated the precision of tactile localization (i.e., the variability across localization attempts). The evidence showed that the dual touches, akin to single touch stimulations, were mislocalized distally and that their variable localization error was reduced near joints, particularly near knuckles. However, contrary to single-touch localization literature, we observed for the dual touches to be mislocalized towards the ulnar side of the hand, particularly when they were presented sequentially. Further, the touches presented in a sequential order were slightly "repelled" from each other and their perceived distance increased, while the simultaneous tactile pairs were localized closer to each other and their distance was compressed. Whereas the sequential touches may have been localized with reference to the body, the compression of tactile perceptual space for simultaneous touches was related in the previous literature to signal summation and inhibition and the low-level factors, including the innervation density and properties of receptive fields (RFs) of somatosensory neurons.

  6. Nanoscale tissue engineering: spatial control over cell-materials interactions

    Science.gov (United States)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G.; Jabbari, Esmaiel; Khademhosseini, Ali

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two- and three-dimensional studies (2- and 3D), and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffolds technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D, however, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and the temporal changes in cellular microenvironment. PMID:21451238

  7. Spatial design and control of graphene flake motion

    Science.gov (United States)

    Ghorbanfekr-Kalashami, H.; Peeters, F. M.; Novoselov, K. S.; Neek-Amal, M.

    2017-08-01

    The force between a sharp scanning probe tip and a surface can drive a graphene flake over crystalline substrates. The recent design of particular patterns of structural defects on a graphene surface allows us to propose an alternative approach for controlling the motion of a graphene flake over a graphene substrate. The thermally induced motion of a graphene flake is controlled by engineering topological defects in the substrate. Such defect regions lead to an inhomogeneous energy landscape and are energetically unfavorable for the motion of the flake, and will invert and scatter graphene flakes when they are moving toward the defect line. Engineering the distribution of these energy barriers results in a controllable trajectory for the thermal motion of the flake without using any external force. We predict superlubricity of the graphene flake for motion along and between particular defect lines. This Rapid Communication provides insights into the frictional forces of interfaces and opens a route to the engineering of the stochastic motion of a graphene flake over any crystalline substrate.

  8. Spatial Control of Crystal Texture by Laser DMD Process

    Science.gov (United States)

    2009-02-01

    Parallel to rolling direction 1120 827 31 205 24 Matweb In718 filler material 1140 414 Charpy Impact Energy (J) Hardness (HRC) Tensile strength (Mpa...J. Choi, K. Nagarathnam, J. Koch, and D. Hetzner, “The direct metal deposition of H13 tool steel for 3-D components,” JOM, 49(5), 1997, 55-60. 4. M...Transactions A, 36A, 2005, 3397-3406. 6. Y. Hua and J. Choi, “Feedback control effects on dimensions and defects of H13 tool steel by DMD process,” J. of Laser Applications, 17(2), 2005, 117-125. 412

  9. Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System.

    Science.gov (United States)

    Bagny Beilhe, Leïla; Piou, Cyril; Tadu, Zéphirin; Babin, Régis

    2018-06-06

    The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.

  10. Controlling phase separation in vanadium dioxide thin films via substrate engineering

    Science.gov (United States)

    Gilbert Corder, Stephanie N.; Jiang, Jianjuan; Chen, Xinzhong; Kittiwatanakul, Salinporn; Tung, I.-Cheng; Zhu, Yi; Zhang, Jiawei; Bechtel, Hans A.; Martin, Michael C.; Carr, G. Lawrence; Lu, Jiwei; Wolf, Stuart A.; Wen, Haidan; Tao, Tiger H.; Liu, Mengkun

    2017-10-01

    The strong electron-lattice interactions in correlated electron systems provide unique opportunities for altering the material properties with relative ease and flexibility. In this Rapid Communication, we use localized strain control via a focused-ion-beam patterning of Ti O2 substrates to demonstrate that one can selectively engineer the insulator-to-metal transition temperature, the fractional component of the insulating and metallic phases, and the degree of optical anisotropy down to the length scales of the intrinsic phase separation in V O2 thin films without altering the quality of the films. The effects of localized strain control on the strongly correlated electron system are directly visualized by state-of-the-art IR near-field imaging and spectroscopy techniques and x-ray microdiffraction measurements.

  11. Separation of oily materials in radioactive waste waters by flotation. Determination of operation and control parameters

    International Nuclear Information System (INIS)

    Ortiz O, H.B.; Flores E, R.M.

    2003-01-01

    In this work the determination of the operation and control parameters (air/solids ratio G/S, retention time Θ, pressure P and de pressurized volume of mixed air-water V), of the flotation system used in the treatment of oleaginous residual water (polluted mainly with 60 Co) coming from the decontamination process of worn out oils, using as response parameters the concentration of oleaginous material and the residual turbidity. The obtained results allowed to observe the dependence of G/S with the pressure and volume of air-water given. At the same time it was settled down that the set of operation conditions that offers the greater separation percentage of G As and turbidity in the smallest time, they are those obtained by V 2 = 0.0012 m 3 and P 2 = 620 kPa, (G/S = 0.30 - 0.35, = 14-16 min) for what were employees as the ideal values of operation and control in the flotation system. As long as, the concentration of total Co is found under 1 mgL -1 . Finally, the selected flotation system showed high separation levels of 60 Co, whose specific activity are below of 0.007 BqmL -1 . (Author)

  12. Control of unsteady separated flow associated with the dynamic pitching of airfoils

    Science.gov (United States)

    Ahmed, Sajeer

    1991-01-01

    Although studies have been done to understand the dependence of parameters for the occurrence of deep stall, studies to control the flow for sustaining lift for a longer time has been little. To sustain the lift for a longer time, an understanding of the development of the flow over the airfoil is essential. Studies at high speed are required to study how the flow behavior is dictated by the effects of compressibility. When the airfoil is pitched up in ramp motion or during the upstroke of an oscillatory cycle, the flow development on the upper surface of the airfoil and the formation of the vortex dictates the increase in lift behavior. Vortex shedding past the training edge decreases the lift. It is not clear what is the mechanism associated with the unsteady separation and vortex formation in present unsteady environment. To develop any flow control device, to suppress the vortex formation or delay separation, it is important that this mechanism be properly understood. The research activities directed toward understanding these questions are presented and the results are summarized.

  13. Active Control of Separation From the Flap of a Supercritical Airfoil

    Science.gov (United States)

    Melton, LaTunia Pack; Yao, Chung-Sheng; Seifert, Avi

    2006-01-01

    Zero-mass-flux periodic excitation was applied at several regions on a simplified high-lift system to delay the occurrence of flow separation. The NASA Energy Efficient Transport (EET) supercritical airfoil was equipped with a 15% chord simply hinged leading edge flap and a 25% chord simply hinged trailing edge flap. Detailed flow features were measured in an attempt to identify optimal actuator placement. The measurements included steady and unsteady model and tunnel wall pressures, wake surveys, arrays of surface hot-films, flow visualization, and particle image velocimetry (PIV). The current paper describes the application of active separation control at several locations on the deflected trailing edge flap. High frequency (F(+) approximately equal to 10) and low frequency amplitude modulation (F(+) sub AM approximately equal to 1) of the high frequency excitation were used for control. It was noted that the same performance gains were obtained with amplitude modulation and required only 30% of the momentum input required by pure sine excitation.

  14. The role of rewarding and novel events in facilitating memory persistence in a separate spatial memory task

    Science.gov (United States)

    Salvetti, Beatrice; Morris, Richard G.M.; Wang, Szu-Han

    2014-01-01

    Many insignificant events in our daily life are forgotten quickly but can be remembered for longer when other memory-modulating events occur before or after them. This phenomenon has been investigated in animal models in a protocol in which weak memories persist longer if exploration in a novel context is introduced around the time of memory encoding. This study aims to understand whether other types of rewarding or novel tasks, such as rewarded learning in a T-maze and novel object recognition, can also be effective memory-modulating events. Rats were trained in a delayed matching-to-place task to encode and retrieve food locations in an event arena. Weak encoding with only one food pellet at the sample location induced memory encoding but forgetting over 24 h. When this same weak encoding was followed by a rewarded task in a T-maze, the memory persisted for 24 h. Moreover, the same persistence of memory over 24 h could be achieved by exploration in a novel box or by a rewarded T-maze task after a “non-rewarded” weak encoding. When the one-pellet weak encoding was followed by novel object exploration, the memory did not persist at 24 h. Together, the results confirm that place encoding is possible without explicit reward, and that rewarded learning in a separate task lacking novelty can be an effective memory-modulating event. The behavioral and neurobiological implications are discussed. PMID:24429424

  15. Spatial flux instabilities, and their control in the graphite gas power reactors; Les instabilites spatiales du flux et leur controle dans les reacteurs de puissance graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Cailly, J L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Radial-azimuthal and axial spatial flux instabilities in graphite-gas reactors are studied by means of an analytical approach. Results are checked with those which are given by two dimensional (r, z and r, {theta}) kinetic models programmed for an IBM 7094 computer. At least, conclusions on the control of instabilities obtained from these models are reported. (author) [French] Les instabilites spatiales du flux dans les reacteurs graphite-gaz, radiales et azimutales d'une part, axiales d'autre part, sont etudiees au moyen d'une formulation analytique. Les resultats sont confrontes avec ceux que fournissent des modeles cinetiques a deux dimensions (r, z et r, {theta}) programmes sur IBM 7094. On donne enfin les conclusions relatives au controle de ces instabilites que ces modeles ont permis de degager. (auteur)

  16. Musical Applications and Design Techniques for the Gametrak Tethered Spatial Position Controller

    DEFF Research Database (Denmark)

    Freed, Adrian; Overholt, Daniel; Hansen, Anne-Marie

    2009-01-01

    The Gametrak spatial position controller has been saved from the fate of so many discontinued gaming controllers to become an attractive and increasingly popular platform for experimental musical controllers, math and science manipulatives, large scale interactive installations and as a playful...... tangible gaming interface that promotes inter-generational creative play and discovery . After introducing the peculiarities of the GameTrak and comparing it to related spatial position sensing systems we survey musical applications of the device. The short paper format cannot do justice to the depth...

  17. The Effects of Sweeping Jet Actuator Parameters on Flow Separation Control

    Science.gov (United States)

    Koklu, Mehti

    2015-01-01

    A parametric experimental study was performed with sweeping jet actuators (fluidic oscillators) to determine their effectiveness in controlling flow separation on an adverse pressure gradient ramp. Actuator parameters that were investigated include blowing coefficients, operation mode, pitch and spreading angles, streamwise location, aspect ratio, and scale. Surface pressure measurements and surface oil flow visualization were used to characterize the effects of these parameters on the actuator performance. 2D Particle Image Velocimetry measurements of the flow field over the ramp and hot-wire measurements of the actuator's jet flow were also obtained for selective cases. In addition, the sweeping jet actuators were compared to other well-known flow control techniques such as micro-vortex generators, steady blowing, and steady vortex-generating jets. The results confirm that the sweeping jet actuators are more effective than steady blowing and steady vortex-generating jets. The results also suggest that an actuator with a larger spreading angle placed closer to the location where the flow separates provides better performance. For the cases tested, an actuator with an aspect ratio, which is the width/depth of the actuator throat, of 2 was found to be optimal. For a fixed momentum coefficient, decreasing the aspect ratio to 1 produced weaker vortices while increasing the aspect ratio to 4 reduced coverage area. Although scaling down the actuator (based on the throat dimensions) from 0.25 inch x 0.125 inch to 0.15 inch x 0.075 inch resulted in similar flow control performance, scaling down the actuator further to 0.075 inch x 0.0375 inch reduced the actuator efficiency by reducing the coverage area and the amount of mixing in the near-wall region. The results of this study provide insight that can be used to design and select the optimal sweeping jet actuator configuration for flow control applications.

  18. Analysis of an atom laser based on the spatial control of the scattering length

    International Nuclear Information System (INIS)

    Carpentier, Alicia V.; Michinel, Humberto; Rodas-Verde, Maria I.; Perez-Garcia, Victor M.

    2006-01-01

    In this paper we analyze atom lasers based on the spatial modulation of the scattering length of a Bose-Einstein condensate. We demonstrate, through numerical simulations and approximate analytical methods, the controllable emission of matter-wave bursts and study the dependence of the process on the spatial shape of the scattering length along the axis of emission. We also study the role of an additional modulation of the scattering length in time

  19. Controlled synthesis of Fe3O4/ZIF-8 nanoparticles for magnetically separable nanocatalysts.

    Science.gov (United States)

    Pang, Fei; He, Mingyuan; Ge, Jianping

    2015-04-27

    Fe3O4/ZIF-8 nanoparticles were synthesized through a room-temperature reaction between 2-methylimidazolate and zinc nitrate in the presence of Fe3O4 nanocrystals. The particle size, surface charge, and magnetic loading can be conveniently controlled by the dosage of Zn(NO3)2 and Fe3O4 nanocrystals. The as-prepared particles show both good thermal stability (stable to 550 °C) and large surface area (1174 m(2) g(-1)). The nanoparticles also have a superparamagnetic response, so that they can strongly respond to an external field during magnetic separation and disperse back into the solution after withdrawal of the magnetic field. For the Knoevenagel reaction, which is catalyzed by alkaline active sites on external surface of catalyst, small Fe3O4/ZIF-8 nanoparticles show a higher catalytic activity. At the same time, the nanocatalysts can be continuously used in multiple catalytic reactions through magnetic separation, activation, and redispersion with little loss of activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Corner Separation Control by Boundary Layer Suction Applied to a Highly Loaded Axial Compressor Cascade

    Directory of Open Access Journals (Sweden)

    Yangwei Liu

    2014-11-01

    Full Text Available Control of corner separation has attracted much interest due to its improvement of performance and energy utilization in turbomachinery. Numerical studies have been performed under both design and off-design flow conditions to investigate the effects of boundary layer suction (BLS on corner separation in a highly loaded compressor cascade. Two new BLS slot configurations are proposed and a total of five suction slot configurations were studied and compared. Averaged static pressure rise, exit loss coefficient, passage blockage and flow turning angle have been given and compared systematically over a range of operation incidence angles. Distributions of significant loss removal, blade loading, exit deviation and total pressure loss at 3 degree and 7 degree incidence have also been studied. Under the same suction mass flows of 0.7% of the inlet mass flows, the pitchwise suction slot on the endwall shows a better optimal performance over the whole operation incidence among single suction slots. By using of the new proposed compound slot configuration with one spanwise slot on the blade suction side and one pitchwise slot on the endwall, the maximum reduction of total pressure loss at 7 degree incidence can be 39.4%.

  1. Control, monitoring and data acquisition systems in pilot plant for tritium and deuterium separation

    International Nuclear Information System (INIS)

    Retevoi, Carmen; Balteanu, Ovidiu Ioan

    1999-01-01

    To achieve the control, monitoring and data acquisition for a pilot plant for tritium and deuterium separation we have developed a system based on computer processing which transfers and treats all the data from the physical system. It consists of six basic elements: 1. a process computer ; 2. a National Instruments Amplifier/Multiplexed - SCXI 1000 with a SCXI 1100 Module with 32 differential input channels; 3. a Honeywell Digital Process Recorder - DPR 250, with 32 universal input, 12 digital input and 12 internal relays; 4. a control system for 4 throttle valves; 5. a National Instruments Data Acquisition board - AT-MIO-16XE-10, with 8 differential channels; 6. a system consisting of up to 20 digital programming current units for carbon RTD's. All the parameters from transducers, sensors and transmitters are introduced into the multiplexer and beyond into the acquisition data board. With LabVIEW soft support (National Instrument product), we made a graphic interface which displays the plant and all the parameters and their points of measure and cumulates all these data into a file. On the other hand all the pressure flow and level values are monitored by the recorder DPR 250, which has a RS232/RS485 port for PC communication. The temperatures are measured with carbon RTD's and a system comprising 20 programming current units connected by RS485 serial bus and a RS485/RS232 converter directly to the serial port of process computer. A special program makes the voltage/temperature conversion. The control system for throttle valves comprises a central unit, which communicates by RS232 bus with 4 controllers commanding 4 stepping motors. Every stepping motor is linked by a reductor to the throttle valve. This system can operate in either manual or automatic mode. The central unit can communicate with process computer via RS232 link. In this way a process computer can receive all the parameters by means of RS232/RS245 link or directly through the multiplexer and

  2. Simulation and control synthesis for a pulse column separation system for plutonium--uranium recovery

    International Nuclear Information System (INIS)

    McCutcheon, E.B.

    1975-05-01

    Control of a plutonium-uranium partitioning column was studied using a mathematical model developed to simulate the dynamic response and to test postulated separation mechanisms. The column is part of a plutonium recycle flowsheet developed for the recovery of plutonium and uranium from metallurgical scrap. In the first step of the process, decontamination from impurities is achieved by coextracting plutonium and uranium in their higher oxidation states. In the second step, reduction of the plutonium to a lower oxidation state allows partitioning of the plutonium and uranium. The use of hydroxylamine for the plutonium reduction in this partitioning column is a unique feature of the process. The extraction operations are carried out in pulse columns. (U.S.)

  3. Environmental and spatial controls of palm (Arecaceae) species richness across the Americas

    DEFF Research Database (Denmark)

    Bjorholm, Stine; Svenning, Jens-Christian; Skov, Flemming

    2005-01-01

    Our analysis suggests that in the Americas, palm species richness at spatial scales from 1° to 10° is most strongly controlled by water availability, although unknown broad-scale factors, perhaps soil, historical processes or geometric constraints, are also important.......Our analysis suggests that in the Americas, palm species richness at spatial scales from 1° to 10° is most strongly controlled by water availability, although unknown broad-scale factors, perhaps soil, historical processes or geometric constraints, are also important....

  4. Beam control and diagnostic functions in the NIF transport spatial filter

    International Nuclear Information System (INIS)

    Holdener, F.R.; Ables, E.; Bliss, E.S.

    1996-10-01

    Beam control and diagnostic systems are required to align the National Ignition Facility (NIF) laser prior to a shot as well as to provide diagnostics on 192 beam lines at shot time. A design that allows each beam's large spatial filter lenses to also serve as objective lenses for beam control and diagnostic sensor packages helps to accomplish the task at a reasonable cost. However, this approach also causes a high concentration of small optics near the pinhole plane of the transport spatial filter (TSF) at the output of each beam. This paper describes the optomechanical design in and near the central vacuum vessel of the TSF

  5. Combined spatial prediction of schistosomiasis and soil-transmitted helminthiasis in Sierra Leone: a tool for integrated disease control.

    Directory of Open Access Journals (Sweden)

    Mary H Hodges

    Full Text Available BACKGROUND: A national mapping of Schistosoma haematobium was conducted in Sierra Leone before the mass drug administration (MDA with praziquantel. Together with the separate mapping of S. mansoni and soil-transmitted helminths, the national control programme was able to plan the MDA strategies according to the World Health Organization guidelines for preventive chemotherapy for these diseases. METHODOLOGY/PRINCIPAL FINDINGS: A total of 52 sites/schools were selected according to prior knowledge of S. haematobium endemicity taking into account a good spatial coverage within each district, and a total of 2293 children aged 9-14 years were examined. Spatial analysis showed that S. haematobium is heterogeneously distributed in the country with significant spatial clustering in the central and eastern regions of the country, most prevalent in Bo (24.6% and 8.79 eggs/10 ml, Koinadugu (20.4% and 3.53 eggs/10 ml and Kono (25.3% and 7.91 eggs/10 ml districts. By combining this map with the previously reported maps on intestinal schistosomiasis using a simple probabilistic model, the combined schistosomiasis prevalence map highlights the presence of high-risk communities in an extensive area in the northeastern half of the country. By further combining the hookworm prevalence map, the at-risk population of school-age children requiring integrated schistosomiasis/soil-transmitted helminth treatment regimens according to the coendemicity was estimated. CONCLUSIONS/SIGNIFICANCE: The first comprehensive national mapping of urogenital schistosomiasis in Sierra Leone was conducted. Using a new method for calculating the combined prevalence of schistosomiasis using estimates from two separate surveys, we provided a robust coendemicity mapping for overall urogenital and intestinal schistosomiasis. We also produced a coendemicity map of schistosomiasis and hookworm. These coendemicity maps can be used to guide the decision making for MDA strategies in combination

  6. Combined spatial prediction of schistosomiasis and soil-transmitted helminthiasis in Sierra Leone: a tool for integrated disease control.

    Science.gov (United States)

    Hodges, Mary H; Soares Magalhães, Ricardo J; Paye, Jusufu; Koroma, Joseph B; Sonnie, Mustapha; Clements, Archie; Zhang, Yaobi

    2012-01-01

    A national mapping of Schistosoma haematobium was conducted in Sierra Leone before the mass drug administration (MDA) with praziquantel. Together with the separate mapping of S. mansoni and soil-transmitted helminths, the national control programme was able to plan the MDA strategies according to the World Health Organization guidelines for preventive chemotherapy for these diseases. A total of 52 sites/schools were selected according to prior knowledge of S. haematobium endemicity taking into account a good spatial coverage within each district, and a total of 2293 children aged 9-14 years were examined. Spatial analysis showed that S. haematobium is heterogeneously distributed in the country with significant spatial clustering in the central and eastern regions of the country, most prevalent in Bo (24.6% and 8.79 eggs/10 ml), Koinadugu (20.4% and 3.53 eggs/10 ml) and Kono (25.3% and 7.91 eggs/10 ml) districts. By combining this map with the previously reported maps on intestinal schistosomiasis using a simple probabilistic model, the combined schistosomiasis prevalence map highlights the presence of high-risk communities in an extensive area in the northeastern half of the country. By further combining the hookworm prevalence map, the at-risk population of school-age children requiring integrated schistosomiasis/soil-transmitted helminth treatment regimens according to the coendemicity was estimated. The first comprehensive national mapping of urogenital schistosomiasis in Sierra Leone was conducted. Using a new method for calculating the combined prevalence of schistosomiasis using estimates from two separate surveys, we provided a robust coendemicity mapping for overall urogenital and intestinal schistosomiasis. We also produced a coendemicity map of schistosomiasis and hookworm. These coendemicity maps can be used to guide the decision making for MDA strategies in combination with the local knowledge and programme needs.

  7. The scope and control of attention as separate aspects of working memory.

    Science.gov (United States)

    Shipstead, Zach; Redick, Thomas S; Hicks, Kenny L; Engle, Randall W

    2012-01-01

    The present study examines two varieties of working memory (WM) capacity task: visual arrays (i.e., a measure of the amount of information that can be maintained in working memory) and complex span (i.e., a task that taps WM-related attentional control). Using previously collected data sets we employ confirmatory factor analysis to demonstrate that visual arrays and complex span tasks load on separate, but correlated, factors. A subsequent series of structural equation models and regression analyses demonstrate that these factors contribute both common and unique variance to the prediction of general fluid intelligence (Gf). However, while visual arrays does contribute uniquely to higher cognition, its overall correlation to Gf is largely mediated by variance associated with the complex span factor. Thus we argue that visual arrays performance is not strictly driven by a limited-capacity storage system (e.g., the focus of attention; Cowan, 2001), but may also rely on control processes such as selective attention and controlled memory search.

  8. Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: Toward controllable oil/water separation

    KAUST Repository

    Zhang, L.

    2012-02-01

    Advanced materials with surfaces that have controllable oil wettability when submerged in aqueous media have great potential for various underwater applications. Here we have developed smart surfaces on commonly used materials, including non-woven textiles and polyurethane sponges, which are able to switch between superoleophilicity and superoleophobicity in aqueous media. The smart surfaces are obtained by grafting a block copolymer, comprising blocks of pH-responsive poly(2-vinylpyridine) and oleophilic/hydrophobic polydimethylsiloxane (i.e., P2VP-b-PDMS) on these materials. The P2VP block can alter its wettability and its conformation via protonation and deprotonation in response to the pH of the aqueous media, which provides controllable and switchable access of oil by the PDMS block, resulting in the switchable surface oil wettability in the aqueous media. On the other hand, the high flexibility of the PDMS block facilitates the reversible switching of the surface oil wettability. As a proof of concept, we also demonstrate that materials functionalized with our smart surfaces can be used for highly controllable oil/water separation processes.

  9. Superconductivity in Ba sub 1 sub - sub x K sub x BiO sub 3 : possible scenario of spatially separated Fermi-Bose mixture

    CERN Document Server

    Menushenkov, A P; Kuznetsov, A V; Kagan, M Y

    2001-01-01

    A new scenario for the metal-insulator phase transition and superconductivity in the perovskite-like bismuthates Ba sub 1 sub - sub x K sub x BiO sub 3 (BKBO) is proposed. It is shown that two types of charge carriers, the local pairs (real-space bosons) and the itinerant electrons, exist in the metallic compound BKBO (x >= 0.37). The real-space bosons are responsible for the charge transport in semiconducting BaBiO sub 3 and for superconductivity in the metallic BKBO. The appearance of the Fermi-liquid state as the percolation threshold is overcome (x >= 0.37) explains the observed metal-insulator phase transition. Because bosons and fermions occupy different types of the octahedral BiO sub 6 complexes, they are separated in real space, and therefore, the spatially separated Fermi-Bose mixture of a new type is likely to be realized in the bismuthates. The nature of superconductivity is consistently explained in the framework of this scenario. A new superconducting oxide Ba sub 1 sub - sub x La sub x PbO sub ...

  10. Vibrations and spatial patterns in biomimetic surfaces: using the shark-skin effect to control blood clotting.

    Science.gov (United States)

    Ramachandran, Rahul; Maani, Nazanin; Rayz, Vitaliy L; Nosonovsky, Michael

    2016-08-06

    We study the effect of small-amplitude fast vibrations and small-amplitude spatial patterns on various systems involving wetting and liquid flow, such as superhydrophobic surfaces, membranes and flow pipes. First, we introduce a mathematical method of averaging the effect of small spatial and temporal patterns and substituting them with an effective force. Such an effective force can change the equilibrium state of a system as well as a phase state, leading to surface texture-induced and vibration-induced phase control. Vibration and patterns can effectively jam holes in vessels with liquid, separate multi-phase flow, change membrane properties, result in propulsion and locomotion and lead to many other multi-scale, nonlinear effects including the shark-skin effect. We discuss the application of such effects to blood flow for novel biomedical 'haemophobic' applications which can prevent blood clotting and thrombosis by controlling the surface pattern at a wall of a vessel (e.g. a catheter or stent).This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  11. Interference between postural control and spatial vs. non-spatial auditory reaction time tasks in older adults.

    Science.gov (United States)

    Fuhrman, Susan I; Redfern, Mark S; Jennings, J Richard; Furman, Joseph M

    2015-01-01

    This study investigated whether spatial aspects of an information processing task influence dual-task interference. Two groups (Older/Young) of healthy adults participated in dual-task experiments. Two auditory information processing tasks included a frequency discrimination choice reaction time task (non-spatial task) and a lateralization choice reaction time task (spatial task). Postural tasks included combinations of standing with eyes open or eyes closed on either a fixed floor or a sway-referenced floor. Reaction times and postural sway via center of pressure were recorded. Baseline measures of reaction time and sway were subtracted from the corresponding dual-task results to calculate reaction time task costs and postural task costs. Reaction time task cost increased with eye closure (p = 0.01), sway-referenced flooring (p vision x age interaction indicated that older subjects had a significant vision X task interaction whereas young subjects did not. However, when analyzed by age group, the young group showed minimal differences in interference for the spatial and non-spatial tasks with eyes open, but showed increased interference on the spatial relative to non-spatial task with eyes closed. On the contrary, older subjects demonstrated increased interference on the spatial relative to the non-spatial task with eyes open, but not with eyes closed. These findings suggest that visual-spatial interference may occur in older subjects when vision is used to maintain posture.

  12. Analysis and Implementation of an Open Programmable Router Based on Forwarding and Control Element Separation

    Institute of Scientific and Technical Information of China (English)

    Wei-Ming Wang; Li-Gang Dong; Bin Zhuge

    2008-01-01

    A router architecture based upon ForCES (Forwarding and Control Element Separation), which is being standardized by IETF ForCES working group, gains its competitive advantage over traditional router architectures in flexibility, programmability, and cost-effectiveness. In this paper, design and implementation of a ForCES-based router (ForTER) is illustrated. Firstly, the implementation architecture of ForTER is discussed. Then, a layered software model,which well illustrates ForCES features, is proposed. Based on the model, design and implementation of Control Element (CE) and Forwarding Element (FE) in ForTER are introduced in detail. Moreover, security for ForTER is considered and an algorithm to prevent DoS attacks is presented. Lastly, experiments of ForTER are illustrated for routing and running routing protocols, network management, DoS attack prevention, etc. The experimental results show the feasibility of the ForTER design. Consequently, the ForTER implementation basically testifies the feasibility of ForCES architecture and some IETF ForCES specifications.

  13. Characterization of Passive Flow-Actuated Microflaps Inspired by Shark Skin for Separation Control

    Science.gov (United States)

    Morris, Jackson; Devey, Sean; Lang, Amy; Hubner, Paul

    2017-11-01

    Thanks to millions of years of natural selection, sharks have evolved into quick apex predators. Previous research has proven shark skin to reduce flow separation, which would result in lower pressure drag. Mako shark skin is made up of microscopic scales on the order of 0.2 mm in size. These scales are hypothesized to be a flow control mechanism, capable of being passively actuated by reversed flow. We believe shark scales are strategically sized to interact with the lower 5 percent of the boundary layer, where reversed flow occurs near the wall. Previous wind tunnel research has shown that it is possible to passively actuate 2D flaps in the lower regions of the boundary layer. This research aims to identify reverse flow conditions that will cause small 3D flaps to actuate. Several sets of microflaps (about 4 mm in length) geometrically similar to shark scales were 3D printed. These microflaps were tested in a low-speed wind tunnel in various reverse flow conditions. Microflaps were observed to be actuated by the reversing flow and flow conditions were characterized using a hot-wire probe. These microflaps have the potential to mimic the mako shark type of flow control in air, passively actuated by reverse flow conditions. This research was supported by Boeing, the US Army, and the National Science Foundation REU program.

  14. Modeling tumor control probability for spatially inhomogeneous risk of failure based on clinical outcome data

    DEFF Research Database (Denmark)

    Lühr, Armin; Löck, Steffen; Jakobi, Annika

    2017-01-01

    PURPOSE: Objectives of this work are (1) to derive a general clinically relevant approach to model tumor control probability (TCP) for spatially variable risk of failure and (2) to demonstrate its applicability by estimating TCP for patients planned for photon and proton irradiation. METHODS AND ...

  15. Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control

    NARCIS (Netherlands)

    Lopez-Galmiche, G.; Eznaveh, Z. Sanjabi; Antonio-Lopez, J.E.; Benitez, A. M. Velazquez; Rodriguez-Asomoza, Jorge; Mondragon, J. J. Sanchez; Gonnet, C.; Sillard, P.; Li, G.; Schülzgen, A.; Okonkwo, C.M.; Amezcua Correa, R.

    2016-01-01

    We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to x223C;6.2x2009;x2009;dBm average power is obtained while maintaining high

  16. Industrial implementation of spatial variability control by real-time SPC

    Science.gov (United States)

    Roule, O.; Pasqualini, F.; Borde, M.

    2016-10-01

    Advanced technology nodes require more and more information to get the wafer process well setup. The critical dimension of components decreases following Moore's law. At the same time, the intra-wafer dispersion linked to the spatial non-uniformity of tool's processes is not capable to decrease in the same proportions. APC systems (Advanced Process Control) are being developed in waferfab to automatically adjust and tune wafer processing, based on a lot of process context information. It can generate and monitor complex intrawafer process profile corrections between different process steps. It leads us to put under control the spatial variability, in real time by our SPC system (Statistical Process Control). This paper will outline the architecture of an integrated process control system for shape monitoring in 3D, implemented in waferfab.

  17. Optimization of spatial light distribution through genetic algorithms for vision systems applied to quality control

    International Nuclear Information System (INIS)

    Castellini, P; Cecchini, S; Stroppa, L; Paone, N

    2015-01-01

    The paper presents an adaptive illumination system for image quality enhancement in vision-based quality control systems. In particular, a spatial modulation of illumination intensity is proposed in order to improve image quality, thus compensating for different target scattering properties, local reflections and fluctuations of ambient light. The desired spatial modulation of illumination is obtained by a digital light projector, used to illuminate the scene with an arbitrary spatial distribution of light intensity, designed to improve feature extraction in the region of interest. The spatial distribution of illumination is optimized by running a genetic algorithm. An image quality estimator is used to close the feedback loop and to stop iterations once the desired image quality is reached. The technique proves particularly valuable for optimizing the spatial illumination distribution in the region of interest, with the remarkable capability of the genetic algorithm to adapt the light distribution to very different target reflectivity and ambient conditions. The final objective of the proposed technique is the improvement of the matching score in the recognition of parts through matching algorithms, hence of the diagnosis of machine vision-based quality inspections. The procedure has been validated both by a numerical model and by an experimental test, referring to a significant problem of quality control for the washing machine manufacturing industry: the recognition of a metallic clamp. Its applicability to other domains is also presented, specifically for the visual inspection of shoes with retro-reflective tape and T-shirts with paillettes. (paper)

  18. Attention and predictions: control of spatial attention beyond the endogenous-exogenous dichotomy

    Directory of Open Access Journals (Sweden)

    Emiliano eMacaluso

    2013-10-01

    Full Text Available The mechanisms of attention control have been extensively studied with a variety of methodologies in animals and in humans. Human studies using non-invasive imaging techniques highlighted a remarkable difference between the pattern of responses in dorsal fronto-parietal regions vs. ventral fronto-parietal regions, primarily lateralized to the right hemisphere. Initially, this distinction at the neuro-physiological level has been related to the distinction between cognitive processes associated with strategic/endogenous vs. stimulus-driven/exogenous of attention control. Nonetheless, quite soon it has become evident that, in almost any situation, attention control entails a complex combination of factors related to both the current sensory input and endogenous aspects associated with the experimental context. Here, we review several of these aspects first discussing the joint contribution of endogenous and stimulus-driven factors during spatial orienting in complex environments and, then, turning to the role of expectations and predictions in spatial re-orienting. We emphasize that strategic factors play a pivotal role for the activation of the ventral system during stimulus-driven control, and that the dorsal system makes use of stimulus-driven signals for top-down control. We conclude that both the dorsal and the ventral fronto-parietal networks integrate endogenous and exogenous signals during spatial attention control and that future investigations should manipulate both these factors concurrently, so as to reveal to full extent of these interactions.

  19. Attention and predictions: control of spatial attention beyond the endogenous-exogenous dichotomy

    Science.gov (United States)

    Macaluso, Emiliano; Doricchi, Fabrizio

    2013-01-01

    The mechanisms of attention control have been extensively studied with a variety of methodologies in animals and in humans. Human studies using non-invasive imaging techniques highlighted a remarkable difference between the pattern of responses in dorsal fronto-parietal regions vs. ventral fronto-parietal (vFP) regions, primarily lateralized to the right hemisphere. Initially, this distinction at the neuro-physiological level has been related to the distinction between cognitive processes associated with strategic/endogenous vs. stimulus-driven/exogenous of attention control. Nonetheless, quite soon it has become evident that, in almost any situation, attention control entails a complex combination of factors related to both the current sensory input and endogenous aspects associated with the experimental context. Here, we review several of these aspects first discussing the joint contribution of endogenous and stimulus-driven factors during spatial orienting in complex environments and, then, turning to the role of expectations and predictions in spatial re-orienting. We emphasize that strategic factors play a pivotal role for the activation of the ventral system during stimulus-driven control, and that the dorsal system makes use of stimulus-driven signals for top-down control. We conclude that both the dorsal and the vFP networks integrate endogenous and exogenous signals during spatial attention control and that future investigations should manipulate both these factors concurrently, so as to reveal to full extent of these interactions. PMID:24155707

  20. Attention and predictions: control of spatial attention beyond the endogenous-exogenous dichotomy.

    Science.gov (United States)

    Macaluso, Emiliano; Doricchi, Fabrizio

    2013-01-01

    The mechanisms of attention control have been extensively studied with a variety of methodologies in animals and in humans. Human studies using non-invasive imaging techniques highlighted a remarkable difference between the pattern of responses in dorsal fronto-parietal regions vs. ventral fronto-parietal (vFP) regions, primarily lateralized to the right hemisphere. Initially, this distinction at the neuro-physiological level has been related to the distinction between cognitive processes associated with strategic/endogenous vs. stimulus-driven/exogenous of attention control. Nonetheless, quite soon it has become evident that, in almost any situation, attention control entails a complex combination of factors related to both the current sensory input and endogenous aspects associated with the experimental context. Here, we review several of these aspects first discussing the joint contribution of endogenous and stimulus-driven factors during spatial orienting in complex environments and, then, turning to the role of expectations and predictions in spatial re-orienting. We emphasize that strategic factors play a pivotal role for the activation of the ventral system during stimulus-driven control, and that the dorsal system makes use of stimulus-driven signals for top-down control. We conclude that both the dorsal and the vFP networks integrate endogenous and exogenous signals during spatial attention control and that future investigations should manipulate both these factors concurrently, so as to reveal to full extent of these interactions.

  1. Integrated Lateral Flow Device for Flow Control with Blood Separation and Biosensing

    Directory of Open Access Journals (Sweden)

    Veronica Betancur

    2017-12-01

    Full Text Available Lateral flow devices are versatile and serve a wide variety of purposes, including medical, agricultural, environmental, and military applications. Yet, the most promising opportunities of these devices for diagnosis might reside in point-of-care (POC applications. Disposable paper-based lateral flow strips have been of particular interest, because they utilize low-cost materials and do not require expensive fabrication instruments. However, there are constraints on tuning flow rates and immunoassays functionalization in papers, as well as technical challenges in sensors’ integration and concentration units for low-abundant molecular detection. In the present work, we demonstrated an integrated lateral flow device that applied the capillary forces with functionalized polymer-based microfluidics as a strategy to realize a portable, simplified, and self-powered lateral flow device (LFD. The polydimethylsiloxane (PDMS surface was rendered hydrophilic via functionalization with different concentrations of Pluronic F127. Controlled flow is a key variable for immunoassay-based applications for providing enough time for protein binding to antibodies. The flow rate of the integrated LFD was regulated by the combination of multiple factors, including Pluronic F127 functionalized surface properties and surface treatments of microchannels, resistance of the integrated flow resistor, the dimensions of the microstructures and the spacing between them in the capillary pump, the contact angles, and viscosity of the fluids. Various plasma flow rates were regulated and achieved in the whole device. The LFD combined the ability to separate high quality plasma from human whole blood by using a highly asymmetric plasma separation membrane, and created controlled and steady fluid flow using capillary forces produced by the interfacial tensions. Biomarker immunoglobulin G (IgG detection from plasma was demonstrated with a graphene nanoelectronic sensor integrated

  2. Active control of massively separated high-speed/base flows with electric arc plasma actuators

    Science.gov (United States)

    DeBlauw, Bradley G.

    The current project was undertaken to evaluate the effects of electric arc plasma actuators on high-speed separated flows. Two underlying goals motivated these experiments. The first goal was to provide a flow control technique that will result in enhanced flight performance for supersonic vehicles by altering the near-wake characteristics. The second goal was to gain a broader and more sophisticated understanding of these complex, supersonic, massively-separated, compressible, and turbulent flow fields. The attainment of the proposed objectives was facilitated through energy deposition from multiple electric-arc plasma discharges near the base corner separation point. The control authority of electric arc plasma actuators on a supersonic axisymmetric base flow was evaluated for several actuator geometries, frequencies, forcing modes, duty cycles/on-times, and currents. Initially, an electric arc plasma actuator power supply and control system were constructed to generate the arcs. Experiments were performed to evaluate the operational characteristics, electromagnetic emission, and fluidic effect of the actuators in quiescent ambient air. The maximum velocity induced by the arc when formed in a 5 mm x 1.6 mm x 2 mm deep cavity was about 40 m/s. During breakdown, the electromagnetic emission exhibited a rise and fall in intensity over a period of about 340 ns. After breakdown, the emission stabilized to a near-constant distribution. It was also observed that the plasma formed into two different modes: "high-voltage" and "low-voltage". It is believed that the plasma may be switching between an arc discharge and a glow discharge for these different modes. The two types of plasma do not appear to cause substantial differences on the induced fluidic effects of the actuator. In general, the characterization study provided a greater fundamental understanding of the operation of the actuators, as well as data for computational model comparison. Preliminary investigations

  3. Improving the Photo-Oxidative Performance of Bi2MoO6 by Harnessing the Synergy between Spatial Charge Separation and Rational Co-Catalyst Deposition.

    Science.gov (United States)

    Wu, Xuelian; Hart, Judy N; Wen, Xiaoming; Wang, Liang; Du, Yi; Dou, Shi Xue; Ng, Yun Hau; Amal, Rose; Scott, Jason

    2018-03-21

    It has been reported that photogenerated electrons and holes can be directed toward specific crystal facets of a semiconductor particle, which is believed to arise from the differences in their surface electronic structures, suggesting that different facets can act as either photoreduction or photo-oxidation sites. This study examines the propensity for this effect to occur in faceted, plate-like bismuth molybdate (Bi 2 MoO 6 ), which is a useful photocatalyst for water oxidation. Photoexcited electrons and holes are shown to be spatially separated toward the {100} and {001}/{010} facets of Bi 2 MoO 6 , respectively, by facet-dependent photodeposition of noble metals (Pt, Au, and Ag) and metal oxides (PbO 2 , MnO x , and CoO x ). Theoretical calculations revealed that differences in energy levels between the conduction bands and valence bands of the {100} and {001}/{010} facets can contribute to electrons and holes being drawn to different surfaces of the plate-like Bi 2 MoO 6 . Utilizing this knowledge, the photo-oxidative capability of Bi 2 MoO 6 was improved by adding an efficient water oxidation co-catalyst, CoO x , to the system, whereby the extent of enhancement was shown to be governed by the co-catalyst location. A greater oxygen evolution occurred when CoO x was selectively deposited on the hole-rich {001}/{010} facets of Bi 2 MoO 6 compared to when CoO x was randomly located across all of the facets. The elevated performance exhibited for the selectively loaded CoO x /Bi 2 MoO 6 was ascribed to the greater opportunity for hole trapping by the co-catalyst being accentuated over other potentially detrimental effects, such as the co-catalyst acting as a recombination medium and/or covering reactive sites. The results indicate that harnessing the synergy between the spatial charge separation and the co-catalyst location on the appropriate facets of plate-like Bi 2 MoO 6 can promote its photocatalytic activity.

  4. Application of 241Am EDXRF in detecting and controlling of rare earth separation process by solvent extraction

    International Nuclear Information System (INIS)

    Yan Chunhua; Jia Jiangtao; Liao Chunsheng; Wang Mingwen; Li Biaoguo; Xu Guangxian

    1996-01-01

    The article investigated a fast EDXRF analysis method by radioisotope excited ( 241 Am) employing a high-purity germanium detector in rare earth separation process by solvent extraction. Applying the method, hydrochloride aqueous samples of SeEuGd/Tb/Dy separation processes were off-line analyzed. Comparative results measured by ICP were also given out. The results show that the method can be used for a wide rare earth concentration range with low error. Being fast, effective, precise and non-destructive, it can be used for on-line analysis to detect and control rare earth separation process by solvent extraction

  5. Active Control of Separation from the Slat Shoulder of a Supercritical Airfoil

    Science.gov (United States)

    Pack, LaTunia G.; Schaeffler, Norman W.; Yao, Chung-Sheng; Seifert, Avi

    2002-01-01

    Active flow control in the form of zero-mass-flux excitation was applied at the slat shoulder of a simplified high-lift airfoil to delay flow separation. The NASA Energy Efficient Transport (EET) supercritical airfoil was equipped with a 15% chord simply hinged leading edge slat and a 25% chord simply hinged trailing edge flap. The cruise configuration data was successfully reproduced, repeating previous experiments. The effects of flap and slat deflection angles on the performance of the airfoil integral parameters were quantified. Detailed flow features were measured as well, in an attempt to identify optimal actuator placement. The measurements included: steady and unsteady model and tunnel wall pressures, wake surveys, arrays of surface hot-films, flow visualization and Particle Image Velocimetry (PIV). High frequency periodic excitation was applied to delay the occurrence of slat stall and improve the maximum lift by 10 to 15%. Low frequency amplitude modulation was used to reduce the oscillatory momentum coefficient by roughly 50% with similar aerodynamic performance.

  6. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    Directory of Open Access Journals (Sweden)

    Arnaud eDechesne

    2014-12-01

    Full Text Available Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates inter-studies comparisons. However, it is clear that the presence and activity of pesticide degraders is often highly spatially variable with coefficients of variation often exceeding 50% and frequently displays nonrandom spatial patterns. A few controlling factors have tentatively been identified across pesticide classes: they include some soil characteristics (pH and some agricultural management practices (pesticide application, tillage, while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance of spatial heterogeneity on the fate of pesticides in soil has been difficult to obtain but modelling and experimental systems that do not include soil’s full complexity reveal that this heterogeneity must be considered to improve prediction of pesticide biodegradation rates or of leaching risks. Overall, studying the spatial heterogeneity of pesticide biodegradation is a relatively new field at the interface of agronomy, microbial ecology, and geosciences and a wealth of novel data is being collected from these different disciplinary perspectives. We make suggestions on possible avenues to take full advantage of these investigations for a better understanding and prediction of the fate of pesticides in soil.

  7. Controlling for unmeasured confounding and spatial misalignment in long-term air pollution and health studies.

    Science.gov (United States)

    Lee, Duncan; Sarran, Christophe

    2015-11-01

    The health impact of long-term exposure to air pollution is now routinely estimated using spatial ecological studies, owing to the recent widespread availability of spatial referenced pollution and disease data. However, this areal unit study design presents a number of statistical challenges, which if ignored have the potential to bias the estimated pollution-health relationship. One such challenge is how to control for the spatial autocorrelation present in the data after accounting for the known covariates, which is caused by unmeasured confounding. A second challenge is how to adjust the functional form of the model to account for the spatial misalignment between the pollution and disease data, which causes within-area variation in the pollution data. These challenges have largely been ignored in existing long-term spatial air pollution and health studies, so here we propose a novel Bayesian hierarchical model that addresses both challenges and provide software to allow others to apply our model to their own data. The effectiveness of the proposed model is compared by simulation against a number of state-of-the-art alternatives proposed in the literature and is then used to estimate the impact of nitrogen dioxide and particulate matter concentrations on respiratory hospital admissions in a new epidemiological study in England in 2010 at the local authority level. © 2015 The Authors. Environmetrics published by John Wiley & Sons Ltd.

  8. Boundary-Layer Separation Control under Low-Pressure Turbine Airfoil Conditions using Glow-Discharge Plasma Actuators

    Science.gov (United States)

    Hultgren, Lennart S.; Ashpis, David E.

    2003-01-01

    Modem low-pressure turbines, in general, utilize highly loaded airfoils in an effort to improve efficiency and to lower the number of airfoils needed. Typically, the airfoil boundary layers are turbulent and fully attached at takeoff conditions, whereas a substantial fraction of the boundary layers on the airfoils may be transitional at cruise conditions due to the change of density with altitude. The strong adverse pressure gradients on the suction side of these airfoils can lead to boundary-layer separation at the latter low Reynolds number conditions. Large separation bubbles, particularly those which fail to reattach, cause a significant degradation of engine efficiency. A component efficiency drop of the order 2% may occur between takeoff and cruise conditions for large commercial transport engines and could be as large as 7% for smaller engines at higher altitude. An efficient means of of separation elimination/reduction is, therefore, crucial to improved turbine design. Because the large change in the Reynolds number from takeoff to cruise leads to a distinct change in the airfoil flow physics, a separation control strategy intended for cruise conditions will need to be carefully constructed so as to incur minimum impact/penalty at takeoff. A complicating factor, but also a potential advantage in the quest for an efficient strategy, is the intricate interplay between separation and transition for the situation at hand. Volino gives a comprehensive discussion of several recent studies on transition and separation under low-pressure-turbine conditions, among them one in the present facility. Transition may begin before or after separation, depending on the Reynolds number and other flow conditions. If the transition occurs early in the boundary layer then separation may be reduced or completely eliminated. Transition in the shear layer of a separation bubble can lead to rapid reattachment. This suggests using control mechanisms to trigger and enhance early

  9. The AIDS epidemic in the Amazon region: a spatial case-control study in Rondonia, Brazil

    Directory of Open Access Journals (Sweden)

    Maria Rita Donalisio

    2013-10-01

    Full Text Available OBJECTIVE To analyze spatial changes in the risk of AIDS and the relationship between AIDS incidence and socioeconomic variables in the state of Rondonia, Amazon region. METHODS A spatial, population case-control study in Rondonia, Brazil, based on 1,780 cases reported to the Epidemiological Surveillance System and controls based on demographic data from 1987 to 2006. The cases were grouped into five consecutive four-year periods. A generalized additive model was adjusted to the data; the dependent variable was the status of the individuals (case or control, and the independent variables were a bi-dimensional spline of the geographic coordinates and some municipality-level socioeconomic variables. The observed values of the Moran’s I test were compared to a reference distribution of values generated under conditions of spatial randomness. RESULTS AIDS risk shows a marked spatial and temporal pattern. The disease incidence is related to socioeconomic variables at the municipal level in Rondônia, such as urbanization and human capital. The highest incidence rates of AIDS are in municipalities along the BR-364 highway and calculations of the Moran’s I test show positive spatial correlation associated with proximity of the municipality to the highway in the third and fourth periods (p = 0.05. CONCLUSIONS Incidence of the disease is higher in municipalities of greater economic wealth and urbanization, and in those municipalities bisected by Rondônia’s main roads. The rapid development associated with the opening up of once remote regions may be accompanied by an increase in these risks to health.

  10. Life-Cycle Cost and Environmental Assessment of Decentralized Nitrogen Recovery Using Ion Exchange from Source-Separated Urine through Spatial Modeling.

    Science.gov (United States)

    Kavvada, Olga; Tarpeh, William A; Horvath, Arpad; Nelson, Kara L

    2017-11-07

    Nitrogen standards for discharge of wastewater effluent into aquatic bodies are becoming more stringent, requiring some treatment plants to reduce effluent nitrogen concentrations. This study aimed to assess, from a life-cycle perspective, an innovative decentralized approach to nitrogen recovery: ion exchange of source-separated urine. We modeled an approach in which nitrogen from urine at individual buildings is sorbed onto resins, then transported by truck to regeneration and fertilizer production facilities. To provide insight into impacts from transportation, we enhanced the traditional economic and environmental assessment approach by combining spatial analysis, system-scale evaluation, and detailed last-mile logistics modeling using the city of San Francisco as an illustrative case study. The major contributor to energy intensity and greenhouse gas (GHG) emissions was the production of sulfuric acid to regenerate resins, rather than transportation. Energy and GHG emissions were not significantly sensitive to the number of regeneration facilities. Cost, however, increased with decentralization as rental costs per unit area are higher for smaller areas. The metrics assessed (unit energy, GHG emissions, and cost) were not significantly influenced by facility location in this high-density urban area. We determined that this decentralized approach has lower cost, unit energy, and GHG emissions than centralized nitrogen management via nitrification-denitrification if fertilizer production offsets are taken into account.

  11. Separate mechanisms for magnitude and order processing in the spatial-numerical association of response codes (SNARC) effect: The strange case of musical note values.

    Science.gov (United States)

    Prpic, Valter; Fumarola, Antonia; De Tommaso, Matteo; Luccio, Riccardo; Murgia, Mauro; Agostini, Tiziano

    2016-08-01

    The spatial-numerical association of response codes (SNARC) effect is considered an evidence of the association between numbers and space, with faster left key-press responses to small numbers and faster right key-press responses to large numbers. We examined whether visually presented note values produce a SNARC-like effect. Differently from numbers, note values are represented as a decreasing left-to-right progression, allowing us to disambiguate the contribution of order and magnitude in determining the direction of the effect. Musicians with formal education performed a note value comparison in Experiment 1 (direct task), a line orientation judgment in Experiment 2 (indirect task), and a detection task in Experiment 3 (indirect task). When note values were task relevant (direct task), participants responded faster to large note values with the left key-press, and vice versa. Conversely, when note values were task irrelevant (indirect tasks), the direction of this association was reversed. This evidence suggests the existence of separate mechanisms underlying the SNARC effect. Namely, an Order-Related Mechanism (ORM) and a Magnitude-Related Mechanism (MRM) that are revealed by different task demands. Indeed, according to a new model we proposed, ordinal and magnitude related information appears to be preferentially involved in direct and indirect tasks, respectively. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  12. PID temperature controller in pig nursery: spatial characterization of thermal environment

    Science.gov (United States)

    de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

    2017-11-01

    The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

  13. PID temperature controller in pig nursery: spatial characterization of thermal environment

    Science.gov (United States)

    de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

    2018-05-01

    The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

  14. PID temperature controller in pig nursery: spatial characterization of thermal environment.

    Science.gov (United States)

    de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

    2017-11-28

    The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

  15. Optimal laser control of molecular wave packet dynamics under the influence of dissipation: possibility of isotope separation

    International Nuclear Information System (INIS)

    Ohtsuki, Yukiyoshi

    2004-01-01

    Possibility of fs-laser-pulse isotope separation is numerically investigated using optimal control theory. Optimal pulses that separate the 1:1 mixture of 79 Br 2 and 28 1 Br 2 are calculated. Quantum interferences induced by the optimally designed fs pulse efficiently enhance the isotope shifts through multiple electronic transitions, which results in a high enrichment factor. When utilizing vibrational multi-photon transitions (a virtual model), an optimal pulse can transfer the two isotopes to specified different vibrational states with almost 100% probability. In the presence of colored noises, the optimal pulse achieves the control with minimum loss of product yields within the bath correlation time. (author)

  16. Electrically and spatially controllable PDLC phase gratings for diffraction and modulation of laser beams

    Energy Technology Data Exchange (ETDEWEB)

    Hadjichristov, Georgi B., E-mail: georgibh@issp.bas.bg [Laboratory of Optics and Spectroscopy, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia (Bulgaria); Marinov, Yordan G.; Petrov, Alexander G. [Laboratory of Biomolecular Layers, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia, Bulgaria (Bulgaria)

    2016-03-25

    We present a study on electrically- and spatially-controllable laser beam diffraction, electrooptic (EO) phase modulation, as well as amplitude-frequency EO modulation by single-layer microscale polymer-dispersed liquid crystal (PDLC) phase gratings (PDLC SLPGs) of interest for device applications. PDLC SLPGs were produced from nematic liquid crystal (LC) E7 in photo-curable NOA65 polymer. The wedge-formed PDLC SLPGs have a continuously variable thickness (2–25 µm). They contain LC droplets of diameters twice as the layer thickness, with a linear-gradient size distribution along the wedge. By applying alternating-current (AC) electric field, the PDLC SLPGs produce efficient: (i) diffraction splitting of transmitted laser beams; (ii) spatial redistribution of diffracted light intensity; (iii) optical phase modulation; (iv) amplitude-frequency modulation, all controllable by the driven AC field and the droplet size gradient.

  17. Closed-loop digital control of nuclear reactors characterized by spatial dynamics

    International Nuclear Information System (INIS)

    Bernard, J.A.; Henry, A.F.; Lanning, D.D.; Meyer, J.E.

    1991-03-01

    This report describes the theoretical development and the evaluation via both simulation and, to a lesser degree, experiment of a digital method for the closed-loop control of power and temperature in reactors characterized by spatial dynamics. The major conclusions of the research are that (1) the sophistication of advanced reactor physics and thermal-hydraulic nodal methods is now such that accurate, real-time models of spatially-dependent, heterogeneous reactor cores can be run on present-generation minicomputers; (2) operation of both present-day commercial reactors as well as the multi-modular reactors now being considered for construction in the United States could be significantly improved by incorporating model-generated information on in-core conditions in a digital controller; and (3) digital controllers for spatially-dependent reactors should have a hierarchical or multi-tiered structure consisting of supervisory algorithms that preclude challenges to the safety system, global control laws designed to provide an optimal response to temperature and power perturbations, and local control laws that maintain parameters such as the margin to departure from nucleate boiling within specification. The technology described is appropriate to present-day pressurized water reactors and to the proposed multi-modular designs. The end-product of this research was a (near) real-time analytic plant-estimation code that was given the acronym POPSICLE for POwer Plant SImulator and ControlLEr. POPSICLE's core neutronics model is based on a quasi-static transient solution of the analytic nodal diffusion equations. 126 refs., 159 figs., 17 tabs

  18. Closed-loop digital control of nuclear reactors characterized by spatial dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J.A. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Nuclear Reactor Lab.); Henry, A.F.; Lanning, D.D.; Meyer, J.E. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Nuclear Engineering)

    1991-03-01

    This report describes the theoretical development and the evaluation via both simulation and, to a lesser degree, experiment of a digital method for the closed-loop control of power and temperature in reactors characterized by spatial dynamics. The major conclusions of the research are that (1) the sophistication of advanced reactor physics and thermal-hydraulic nodal methods is now such that accurate, real-time models of spatially-dependent, heterogeneous reactor cores can be run on present-generation minicomputers; (2) operation of both present-day commercial reactors as well as the multi-modular reactors now being considered for construction in the United States could be significantly improved by incorporating model-generated information on in-core conditions in a digital controller; and (3) digital controllers for spatially-dependent reactors should have a hierarchical or multi-tiered structure consisting of supervisory algorithms that preclude challenges to the safety system, global control laws designed to provide an optimal response to temperature and power perturbations, and local control laws that maintain parameters such as the margin to departure from nucleate boiling within specification. The technology described is appropriate to present-day pressurized water reactors and to the proposed multi-modular designs. The end-product of this research was a (near) real-time analytic plant-estimation code that was given the acronym POPSICLE for POwer Plant SImulator and ControlLEr. POPSICLE's core neutronics model is based on a quasi-static transient solution of the analytic nodal diffusion equations. 126 refs., 159 figs., 17 tabs.

  19. DNS for Flow Separation Control Around Airfoil by Steady and Pulsed Jets

    National Research Council Canada - National Science Library

    Deng, Shutian; Jiang, Li; Liu, Chaoqun

    2004-01-01

    This work consists of two parts. The first part is direct numerical simulation (DNS) for flow separation and transition around a NACA 0012 airfoil with an attack angle of 4 degrees and Reynolds number of 100,000...

  20. Temporal changes of spatial soil moisture patterns: controlling factors explained with a multidisciplinary approach

    Science.gov (United States)

    Martini, Edoardo; Wollschläger, Ute; Kögler, Simon; Behrens, Thorsten; Dietrich, Peter; Reinstorf, Frido; Schmidt, Karsten; Weiler, Markus; Werban, Ulrike; Zacharias, Steffen

    2016-04-01

    Characterizing the spatial patterns of soil moisture is critical for hydrological and meteorological models, as soil moisture is a key variable that controls matter and energy fluxes and soil-vegetation-atmosphere exchange processes. Deriving detailed process understanding at the hillslope scale is not trivial, because of the temporal variability of local soil moisture dynamics. Nevertheless, it remains a challenge to provide adequate information on the temporal variability of soil moisture and its controlling factors. Recent advances in wireless sensor technology allow monitoring of soil moisture dynamics with high temporal resolution at varying scales. In addition, mobile geophysical methods such as electromagnetic induction (EMI) have been widely used for mapping soil water content at the field scale with high spatial resolution, as being related to soil apparent electrical conductivity (ECa). The objective of this study was to characterize the spatial and temporal pattern of soil moisture at the hillslope scale and to infer the controlling hydrological processes, integrating well established and innovative sensing techniques, as well as new statistical methods. We combined soil hydrological and pedological expertise with geophysical measurements and methods from digital soil mapping for designing a wireless soil moisture monitoring network. For a hillslope site within the Schäfertal catchment (Central Germany), soil water dynamics were observed during 14 months, and soil ECa was mapped on seven occasions whithin this period of time using an EM38-DD device. Using the Spearman rank correlation coefficient, we described the temporal persistence of a dry and a wet characteristic state of soil moisture as well as the switching mechanisms, inferring the local properties that control the observed spatial patterns and the hydrological processes driving the transitions. Based on this, we evaluated the use of EMI for mapping the spatial pattern of soil moisture under

  1. Spatial and temporal control of thermal waves by using DMDs for interference based crack detection

    Science.gov (United States)

    Thiel, Erik; Kreutzbruck, Marc; Ziegler, Mathias

    2016-02-01

    Active Thermography is a well-established non-destructive testing method and used to detect cracks, voids or material inhomogeneities. It is based on applying thermal energy to a samples' surface whereas inner defects alter the nonstationary heat flow. Conventional excitation of a sample is hereby done spatially, either planar (e.g. using a lamp) or local (e.g. using a focused laser) and temporally, either pulsed or periodical. In this work we combine a high power laser with a Digital Micromirror Device (DMD) allowing us to merge all degrees of freedom to a spatially and temporally controlled heat source. This enables us to exploit the possibilities of coherent thermal wave shaping. Exciting periodically while controlling at the same time phase and amplitude of the illumination source induces - via absorption at the sample's surface - a defined thermal wave propagation through a sample. That means thermal waves can be controlled almost like acoustical or optical waves. However, in contrast to optical or acoustical waves, thermal waves are highly damped due to the diffusive character of the thermal heat flow and therefore limited in penetration depth in relation to the achievable resolution. Nevertheless, the coherence length of thermal waves can be chosen in the mmrange for modulation frequencies below 10 Hz which is perfectly met by DMD technology. This approach gives us the opportunity to transfer known technologies from wave shaping techniques to thermography methods. We will present experiments on spatial and temporal wave shaping, demonstrating interference based crack detection.

  2. CENTRIFUGAL SEPARATORS

    Science.gov (United States)

    Skarstrom, C.

    1959-03-10

    A centrifugal separator is described for separating gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum separation of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.

  3. Control Strategy of Two Capacitor Voltages for Separate MPPTs in Photovoltaic Systems Using Neutral-Point-Clamped Inverters

    DEFF Research Database (Denmark)

    Choi, Ui-Min; Blaabjerg, Frede; Lee, Kyo-Beum

    2015-01-01

    The centralized topology with three-level inverters are widely used in photovoltaic (PV) systems due to their less installation costs and complexity. However, the common maximum power point tracking (MPPT) is a disadvantage of the centralized topology particularly under the partial shading...... and panel mismatch conditions. In this system, if PV modules are separately connected to the split capacitor voltage, the MPPT efficiency can be improved by the proposed control strategy. By the proposed method, the two capacitor voltages can be controlled asymmetrically to perform the separate MPPTs...... of each PV module connected to separate capacitors. The outputs can be generated without distortion even if two capacitors are asymmetrically regulated. Simulation and experimental results verify the validity and feasibility of the proposed methods....

  4. Space power(s) gender – socio- spatial control of prostitution and the bourgeois gender order

    OpenAIRE

    Ruhne, Renate

    2015-01-01

    Using the example of the city of Frankfurt am Main the paper    examines the conflict relationship between increasing acceptance and persistent demands for stringent controls that characterizes the perception of prostitution in Germany today. Focusing on prevalent socio-spatial forms of control, that aim at excluding the field from « normal » everyday life, the first part will demonstrate how and why prostitution, though legalized and more and more accepted, remains   powerfully stigmatized t...

  5. Spatially controlled synthesis of silver nanoparticles and nanowires by photosensitized reduction

    Energy Technology Data Exchange (ETDEWEB)

    Jradi, S; Zeng, X H; Plain, J; Royer, P; Bachelot, R; Akil, S [Laboratoire de Nanotechnologie et d' Instrumentation Optique, ICD CNRS FRE 2848, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes (France); Balan, L; Lougnot, D J; Soppera, O; Vidal, L, E-mail: lavinia.balan@uha.fr [Institut de Science des Materiaux de Mulhouse CNRS LRC 7228, 15 rue Jean Starcky, 68057 Mulhouse (France)

    2010-03-05

    The present paper reports on the spatially controlled synthesis of silver nanoparticles (NPs) and silver nanowires by photosensitized reduction. In a first approach, direct photogeneration of silver NPs at the end of an optical fiber was carried out. Control of both size and density of silver NPs was possible by changing the photonic conditions. In a further development, a photochemically assisted procedure allowing silver to be deposited at the surface of a polymer microtip was implemented. Finally, polymer tips terminated by silver nanowires were fabricated by simultaneous photopolymerization and silver photoreduction. The silver NPs were characterized by UV-visible spectroscopy and scanning electron microscopy.

  6. Effects of Artificial Gravity and Bed Rest on Spatial Orientation and Balance Control

    Science.gov (United States)

    Paloski, William H.; Moore, S. T.; Feiveson, A. H.; Taylor, L. C.

    2007-01-01

    While the vestibular system should be well-adapted to bed rest (a condition it experiences approximately 8/24 hrs each day), questions remain regarding the degree to which repeated exposures to the unusual gravito-inertial force environment of a short-radius centrifuge might affect central processing of vestibular information used in spatial orientation and balance control. Should these functions be impaired by intermittent AG, its feasibility as a counter-measure would be diminished. We, therefore, examined the effects of AG on spatial orientation and balance control in 15 male volunteers before and after 21 days of 6 HDT bed rest (BR). Eight of the subjects were treated with daily 1hr AG exposures (2.5g at the feet; 1.0g at the heart) aboard a short radius (3m) centrifuge, while the other seven served as controls (C). Spatial orientation was assessed by measures of ocular counter-rolling (OCR; rotation of the eye about the line of sight, an otolith-mediated reflex) and subjective visual vertical (SVV; perception of the spatial upright). Both OCR and SVV measurements were made with the subject upright, lying on their left sides, and lying on their right sides. OCR was measured from binocular eye orientation recordings made while the subjects fixated for 10s on a point target directly in front of the face at a distance of 1 m. SVV was assessed by asking subjects (in the dark) to adjust to upright (using a handheld controller) the orientation of a luminous bar randomly perturbed (15) to either side of the vertical meridian. Balance control performance was assessed using a computerized dynamic posturography (CDP) protocol similar to that currently required for all returning crew members. During each session, the subjects completed a combination of trials of sensory organization test (SOT) 2 (eyes closed, fixed platform) and SOT 5 (eyes closed, sway-referenced platform) with and without static and dynamic pitch plane head movements (plus or minus 20 deg., dynamic

  7. In Search of the Sources of Psychologically Controlling Parenting: The Role of Parental Separation Anxiety and Parental Maladaptive Perfectionism

    Science.gov (United States)

    Soenens, Bart; Vansteenkiste, Maarten; Duriez, Bart; Goossens, Luc

    2006-01-01

    This study investigated the role of two dimensions of parental separation anxiety--Anxiety about Adolescent Distancing (AAD) and Comfort with Secure Base Role (CSBR)--and parental maladaptive perfectionism in the prediction of psychologically controlling parenting. In a sample of middle adolescents and their parents (N=677), it was found that…

  8. A separation theorem for the stochastic sampled-data LQG problem. [control of continuous linear plant disturbed by white noise

    Science.gov (United States)

    Halyo, N.; Caglayan, A. K.

    1976-01-01

    This paper considers the control of a continuous linear plant disturbed by white plant noise when the control is constrained to be a piecewise constant function of time; i.e. a stochastic sampled-data system. The cost function is the integral of quadratic error terms in the state and control, thus penalizing errors at every instant of time while the plant noise disturbs the system continuously. The problem is solved by reducing the constrained continuous problem to an unconstrained discrete one. It is shown that the separation principle for estimation and control still holds for this problem when the plant disturbance and measurement noise are Gaussian.

  9. Acetaminophen Versus Liquefied Ibuprofen for Control of Pain During Separation in Orthodontic Patients: A Randomized Triple Blinded Clinical Trial

    Directory of Open Access Journals (Sweden)

    Tahereh Hosseinzadeh Nik

    2016-07-01

    Full Text Available The aim of this randomized clinical study was to investigate the effectiveness of acetaminophen 650 mg or liquefied ibuprofen 400 mg in pain control of orthodontic patients during separation with an elastic separator. A total of 101 patients with specific inclusion criteria were divided randomly into three groups (acetaminophen, liquefied ibuprofen, and placebo. They were instructed to take their drugs one hour before separator placement and every six hours afterward (five doses in total. They recorded their discomfort on visual analog scales immediately after separator placement, 2 hours later, 6 hours later, at bedtime, and 24 hours after separator placement. Repeated measure analysis of variance (ANOVA was used to compare the mean pain scores between the three groups. Data were collected from 89 patients. The pain increased with time in all groups. Pain scores were statistically lower in the analgesic groups compared with the placebo group (P.value<0.001, but no statistically significant difference was found in mean pain scores between the two drug groups (acetaminophen and liquefied ibuprofen (P.value=1. Acetaminophen and liquefied ibuprofen have similar potential in pain reduction during separation.

  10. Numerical Study of Water Control with Downhole Oil-Water Separation Technology

    Directory of Open Access Journals (Sweden)

    Yin Khor Yin

    2014-07-01

    Full Text Available The maturing oil fields with increasing water production can pose a challenging produced water handling and disposal issues. This paper presents a numerical study of a motorless hydrocyclone to enhance understanding of the downhole oil-water separation. The turbulence of fluid flow is obtained using K-ε Realizable Turbulence model for complex swirl dominated flow, while the interface between hydrocarbon and water is described using the Discrete Phase model. In this approach, factors which contribute to the hydrocyclone separation instability were discussed. Discussion is then extended to the relationship of residence time with pressure difference between overflow and underflow. These pressure differences are able to relate to pressure condition for high water cut well which require downhole separation.

  11. A Pressure Controlled Pinched Flow Fractionation Device for Continuous Particle Separation

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Trosborg, Jacqueline; Tanzi, Simone

    2012-01-01

    In this work the problem of separating small particles of di↵erent sizes is solved by developing a simple microfluidic device using pinched flow fractionation (PFF), a technique originally presented by Yamada et al. in 2004 [1]. The present work takes the concept of PFF to the next level by makin...... Polymers GmbH) using a micro machined silicon master. The functionality of the device was confirmed using polymer beads, and by adjusting the pressure accordingly a complete separation of 2 μm and 4.5 μm beads was demonstrated....

  12. Dentate gyrus mossy cells control spontaneous convulsive seizures and spatial memory.

    Science.gov (United States)

    Bui, Anh D; Nguyen, Theresa M; Limouse, Charles; Kim, Hannah K; Szabo, Gergely G; Felong, Sylwia; Maroso, Mattia; Soltesz, Ivan

    2018-02-16

    Temporal lobe epilepsy (TLE) is characterized by debilitating, recurring seizures and an increased risk for cognitive deficits. Mossy cells (MCs) are key neurons in the hippocampal excitatory circuit, and the partial loss of MCs is a major hallmark of TLE. We investigated how MCs contribute to spontaneous ictal activity and to spatial contextual memory in a mouse model of TLE with hippocampal sclerosis, using a combination of optogenetic, electrophysiological, and behavioral approaches. In chronically epileptic mice, real-time optogenetic modulation of MCs during spontaneous hippocampal seizures controlled the progression of activity from an electrographic to convulsive seizure. Decreased MC activity is sufficient to impede encoding of spatial context, recapitulating observed cognitive deficits in chronically epileptic mice. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  13. Inverse Opal Scaffolds with Gradations in Mineral Content for Spatial Control of Osteogenesis.

    Science.gov (United States)

    Zhu, Chunlei; Qiu, Jichuan; Pongkitwitoon, Suphannee; Thomopoulos, Stavros; Xia, Younan

    2018-05-30

    The design and fabrication of inverse opal scaffolds with gradations in mineral content to achieve spatial control of osteogenesis are described. The gradient in mineral content is established via the diffusion-limited transport of hydroxyapatite nanoparticles in a closely packed lattice of gelatin microbeads. The mineral-graded scaffold has an array of uniform pores and interconnected windows to facilitate efficient transport of nutrients and metabolic wastes, ensuring high cell viability. The graded distribution of mineral content can provide biochemical and mechanical cues for spatially regulating the osteogenic differentiation of adipose-derived stromal cells. This new class of scaffolds holds promise for engineering the interfaces between mineralized and unmineralized tissues. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Physical Property Control on the Cellular Uptake Pathway and Spatial Distribution of Nanoparticles in Cells.

    Science.gov (United States)

    Ahn, Sungsook; Seo, Eunseok; Kim, Ki Hean; Lee, Sang Joon

    2015-06-01

    Nanoparticles have been developed in broad biomedical research in terms of effective cellular interactions to treat and visualize diseased cells. Considering the charge and polar functional groups of proteins that are embedded in cellular membranes, charged nanoparticles have been strategically developed to enhance electrostatic cellular interactions. In this study, we show that cellular uptake efficiency, pathway, and spatial distribution of gold nanoparticles in a cell are significantly modulated based on the surface condition of gold nanoparticles and human cancer cells that were tuned by controlling the pH of the medium and by introducing an electron beam. Cellular uptake efficiency is increased when electrostatic attraction is induced between the cells and the gold nanoparticles. Cell surface modification changes the cellular uptake pathways of the gold nanoparticles and concentrates the gold nanoparticles at the membrane region. Surface modification of the gold nanoparticles also contributes to deep penetration and homogeneous spatial distributions in a cell.

  15. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Badawi, N.; Aamand, Jens

    2014-01-01

    across pesticide classes: they include some soil characteristics (pH) and some agricultural management practices (pesticide application, tillage), while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance......Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we...... critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates...

  16. A Matter of Balance: Motor Control is Related to Children’s Spatial and Proportional Reasoning Skills

    Science.gov (United States)

    Frick, Andrea; Möhring, Wenke

    2016-01-01

    Recent research has shown close links between spatial and mathematical thinking and between spatial abilities and motor skills. However, longitudinal research examining the relations between motor, spatial, and mathematical skills is rare, and the nature of these relations remains unclear. The present study thus investigated the relation between children’s motor control and their spatial and proportional reasoning. We measured 6-year-olds’ spatial scaling (i.e., the ability to reason about different-sized spaces), their mental transformation skills, and their ability to balance on one leg as an index for motor control. One year later (N = 126), we tested the same children’s understanding of proportions. We also assessed several control variables (verbal IQ and socio-economic status) as well as inhibitory control, visuo-spatial and verbal working memory. Stepwise hierarchical regressions showed that, after accounting for effects of control variables, children’s balance skills significantly increased the explained variance in their spatial performance and proportional reasoning. Our results suggest specific relations between balance skills and spatial as well as proportional reasoning skills that cannot be explained by general differences in executive functioning or intelligence. PMID:26793157

  17. DNA methylation changes separate allergic patients from healthy controls and may reflect altered CD4+ T-cell population structure.

    Directory of Open Access Journals (Sweden)

    Colm E Nestor

    2014-01-01

    Full Text Available Altered DNA methylation patterns in CD4(+ T-cells indicate the importance of epigenetic mechanisms in inflammatory diseases. However, the identification of these alterations is complicated by the heterogeneity of most inflammatory diseases. Seasonal allergic rhinitis (SAR is an optimal disease model for the study of DNA methylation because of its well-defined phenotype and etiology. We generated genome-wide DNA methylation (N(patients = 8, N(controls = 8 and gene expression (N(patients = 9, Ncontrols = 10 profiles of CD4(+ T-cells from SAR patients and healthy controls using Illumina's HumanMethylation450 and HT-12 microarrays, respectively. DNA methylation profiles clearly and robustly distinguished SAR patients from controls, during and outside the pollen season. In agreement with previously published studies, gene expression profiles of the same samples failed to separate patients and controls. Separation by methylation (N(patients = 12, N(controls = 12, but not by gene expression (N(patients = 21, N(controls = 21 was also observed in an in vitro model system in which purified PBMCs from patients and healthy controls were challenged with allergen. We observed changes in the proportions of memory T-cell populations between patients (N(patients = 35 and controls (N(controls = 12, which could explain the observed difference in DNA methylation. Our data highlight the potential of epigenomics in the stratification of immune disease and represents the first successful molecular classification of SAR using CD4(+ T cells.

  18. Light-induced spatial control of pH-jump reaction at smart gel interface.

    Science.gov (United States)

    Techawanitchai, Prapatsorn; Ebara, Mitsuhiro; Idota, Naokazu; Aoyagi, Takao

    2012-11-01

    We proposed here a 'smart' control of an interface movement of proton diffusion in temperature- and pH-responsive hydrogels using a light-induced spatial pH-jump reaction. A photoinitiated proton-releasing reaction of o-nitrobenzaldehyde (NBA) was integrated into poly(N-isopropylacrylamide-o-2-carboxyisopropylacrylamide) (P(NIPAAm-co-CIPAAm)) hydrogels. NBA-integrated hydrogels demonstrated quick release of proton upon UV irradiation, allowing the pH inside the gel to decrease below the pK(a) of P(NIPAAm-co-CIPAAm) within a minute. The NBA-integrated gel was shown to shrink rapidly upon UV irradiation without polymer "skin layer" formation due to a uniform decrease of pH inside the gel. Spatial control of gel shrinking was also created by irradiating UV light to a limited region of the gel through a photomask. The interface of proton diffusion ("active interface") gradually moved toward non-illuminated area. The apparent position of "active interface", however, did not change remarkably above the LCST, while protons continuously diffused outward direction. This is because the "active interface" also moved inward direction as gel shrank above the LCST. As a result, slow movement of the apparent interface was observed. The NBA-integrated gel was also successfully employed for the controlled release of an entrapped dextran in a light controlled manner. This system is highly promising as smart platforms for triggered and programmed transportation of drugs. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. The effect of oil and gas content on the controllability and separation in a de-oiling hydrocyclone

    OpenAIRE

    Belaidi, Hafid

    2003-01-01

    The effect of free gas on cyclonic oil-water separation was examined using a geometry which sought to minimise problems with gas. Tests were carried out using the purpose built oil-water separation facility at Bradford University where pre-choke conditions could be partially simulated. Firstly, tests were carried out with water and gas-water to look at flow behaviour and control parameters, then comparative tests carried out with gas-oil-water. Comparisons were also made with tests data from ...

  20. Co-crystallization as a separation technology: controlling product concentrations by co-crystals

    NARCIS (Netherlands)

    Urbanus, J.; Roelands, C.P.M.; Verdoes, D.; Jansens, P.J.; Horst, J.H. ter

    2010-01-01

    Co-crystallization is known as a product formulation technology, but it can also be used as a tool to solve crystallization problems. Product removal by co-crystallization in fermentations is used as a showcase to demonstrate the potential of co-crystallization as a separation technique. In

  1. Crystal Nucleation and Polymorph Control : Self-­association, Template Nucleation, Liquid?Liquid, phase Separation

    NARCIS (Netherlands)

    Kulkarni, S.

    2014-01-01

    Crystallization is an essential step in many processes in chemical industries, ranging from bulk chemicals to special products. It is a separation and purification technique that results in a solid particulate product, which is generally preferred in the pharmaceutical industry. The crystal product

  2. Are Separate Black and White MMPI Norms Needed?: An IQ-Controlled Comparison of Accused Murderers.

    Science.gov (United States)

    Holcomb, William R.; And Others

    1984-01-01

    Investigated racial differences in the Minnesota Multiphasic Personality Inventory by comparing samples of Black and White men charged with murder (N=160). Results indicated Black murderers tend to deny symptoms of pathology and are more socially outgoing. The confounding effects of intelligence suggested separate Black and White norms are…

  3. pH control structure design for a periodically operated membrane separation process

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Jørgensen, Sten Bay; Jonsson, Gunnar Eigil

    2012-01-01

    A bioreactor integrated with an electrically driven membrane separation process (Reverse Electro-Enhanced Dialysis – REED) is under investigation as potential technology for intensifying lactic acid bioproduction. In this contribution the pH regulation issue in the periodically operated REED module...

  4. Modeling, fabrication and plasma actuator coupling of flexible pressure sensors for flow separation detection and control in aeronautical applications

    International Nuclear Information System (INIS)

    Francioso, L; De Pascali, C; Siciliano, P; Pescini, E; De Giorgi, M G

    2016-01-01

    Preventing the flow separation could enhance the performance of propulsion systems and future civil aircraft. To this end, a fast detection of boundary layer separation is mandatory for a sustainable and successful application of active flow control devices, such as plasma actuators. The present work reports on the design, fabrication and functional tests of low-cost capacitive pressure sensors coupled with dielectric barrier discharge (DBD) plasma actuators to detect and then control flow separation. Finite element method (FEM) simulations were used to obtain information on the deflection and the stress distribution in different-shaped floating membranes. The sensor sensitivity as a function of the pressure load was also calculated by experimental tests. The results of the calibration of different capacitive pressure sensors are reported in this work, together with functional tests in a wind tunnel equipped with a curved wall plate on which a DBD plasma actuator was mounted to control the flow separation. The flow behavior was experimentally investigated by particle image velocimetry (PIV) measurements. Statistical and spectral analysis, applied to the output signals of the pressure sensor placed downstream of the profile leading edge, demonstrated that the sensor is able to discriminate different ionic wind velocity and turbulence conditions. The sensor sensitivity in the 0–100 Pa range was experimentally measured and it ranged between 0.0030 and 0.0046 pF Pa −1 for the best devices. (paper)

  5. Modeling, fabrication and plasma actuator coupling of flexible pressure sensors for flow separation detection and control in aeronautical applications

    Science.gov (United States)

    Francioso, L.; De Pascali, C.; Pescini, E.; De Giorgi, M. G.; Siciliano, P.

    2016-06-01

    Preventing the flow separation could enhance the performance of propulsion systems and future civil aircraft. To this end, a fast detection of boundary layer separation is mandatory for a sustainable and successful application of active flow control devices, such as plasma actuators. The present work reports on the design, fabrication and functional tests of low-cost capacitive pressure sensors coupled with dielectric barrier discharge (DBD) plasma actuators to detect and then control flow separation. Finite element method (FEM) simulations were used to obtain information on the deflection and the stress distribution in different-shaped floating membranes. The sensor sensitivity as a function of the pressure load was also calculated by experimental tests. The results of the calibration of different capacitive pressure sensors are reported in this work, together with functional tests in a wind tunnel equipped with a curved wall plate on which a DBD plasma actuator was mounted to control the flow separation. The flow behavior was experimentally investigated by particle image velocimetry (PIV) measurements. Statistical and spectral analysis, applied to the output signals of the pressure sensor placed downstream of the profile leading edge, demonstrated that the sensor is able to discriminate different ionic wind velocity and turbulence conditions. The sensor sensitivity in the 0-100 Pa range was experimentally measured and it ranged between 0.0030 and 0.0046 pF Pa-1 for the best devices.

  6. $H_2$ optimal controllers with observer based architecture for continuous-time systems : separation principle

    NARCIS (Netherlands)

    Saberi, A.; Sannuti, P.; Stoorvogel, A.A.

    1994-01-01

    For a general H2 optimal control problem, at first all Hz optimal measurement feedback controllers are characterized and parameterized, and then attention is focused on controllers with observer based architecture. Both full order as well as reduced order observer based H2 optimal controllers are

  7. Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

    KAUST Repository

    Hellmann, Christoph

    2014-12-17

    © 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

  8. Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

    KAUST Repository

    Hellmann, Christoph; Treat, Neil D.; Scaccabarozzi, Alberto D.; Razzell Hollis, Joseph; Fleischli, Franziska D.; Bannock, James H.; de Mello, John; Michels, Jasper J.; Kim, Ji-Seon; Stingelin, Natalie

    2014-01-01

    © 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

  9. Spatial Control of Functional Response in 4D-Printed Active Metallic Structures

    Science.gov (United States)

    Ma, Ji; Franco, Brian; Tapia, Gustavo; Karayagiz, Kubra; Johnson, Luke; Liu, Jun; Arroyave, Raymundo; Karaman, Ibrahim; Elwany, Alaa

    2017-04-01

    We demonstrate a method to achieve local control of 3-dimensional thermal history in a metallic alloy, which resulted in designed spatial variations in its functional response. A nickel-titanium shape memory alloy part was created with multiple shape-recovery stages activated at different temperatures using the selective laser melting technique. The multi-stage transformation originates from differences in thermal history, and thus the precipitate structure, at various locations created from controlled variations in the hatch distance within the same part. This is a first example of precision location-dependent control of thermal history in alloys beyond the surface, and utilizes additive manufacturing techniques as a tool to create materials with novel functional response that is difficult to achieve through conventional methods.

  10. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    International Nuclear Information System (INIS)

    Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.; Carley, Jack; Corbin, Gail A.; Carroll, Sue L.; Watson, David B.; Jardine, Phil M.; Zhou, Jizhong; Criddle, Craig S.; Fields, Matthew W.

    2009-01-01

    Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

  11. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.; Carley, Jack; Corbin, Gail A.; Carroll, Sue L.; Watson, David B.; Jardine, Phil M.; Zhou, Jizhong; Criddle, Craig S.; Fields, Matthew W.

    2009-05-22

    Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

  12. Separation of ownership and control in South African-listed companies

    Directory of Open Access Journals (Sweden)

    Blanché Steyn

    2013-09-01

    The article finds that the majority of listed companies in South Africa are controlled by a dominant shareholder. However, there are still a significant number of companies where the directors have de facto control. Contrary to the expectation that companies controlled by directors will aim to maximise directors’ remuneration, or companies controlled by shareholders will aim to maximise profit attributable to shareholders, this article finds the opposite to be true. This is possibly an indication that the controlling parties might consider factors other than their direct financial self-interest, or that there is an inherent cost associated with control.

  13. SEPARATION OF CELL POPULATIONS BY SUPER-PARAMAGNETIC PARTICLES WITH CONTROLLED SURFACE FUNCTIONALITY

    Directory of Open Access Journals (Sweden)

    Lootsik M. D.

    2014-02-01

    Full Text Available The recognition and isolation of specific mammalian cells by the biocompatible polymer coated super-paramagnetic particles with determined surface functionality were studied. The method of synthesis of nanoscaled particles on a core of iron III oxide (Fe2O3, magemit coated with a polymer shell containing reactive oligoperoxide groups for attachment of ligands is described. By using the developed superparamagnetic particles functionalized with peanut agglutinin (PNA we have separated the sub-populations of PNA+ and PNA– cells from ascites of murine Nemeth-Kellner lymphoma. In another type of experiment, the particles were opsonized with proteins of the fetal calf serum that improved biocompatibility of the particles and their ingestion by cultivated murine macrophages J774.2. Macrophages loaded with the particles were effeciently separated from the particles free cells by using the magnet. Thus, the developed surface functionalized superparamagnetic particles showed to be a versatile tool for cell separation independent on the mode of particles’ binding with cell surface or their engulfment by the targeted cells.

  14. Control of xenon spatial oscillations during load follow of nuclear reactor via robust servo systems

    International Nuclear Information System (INIS)

    Ukai, Hiroyuki; Yada, Yukihiro; Iwazumi, Tetsuo; Morita, Yoshifumi.

    1990-01-01

    This paper investigates the control problem of xenon spatial oscillations in the axial direction during load following operations of a nuclear reactor. The system model is described by a one-group diffusion equation with xenon and power feedbacks and iodine-xenon dynamic equations and controlled by full-length and part-length control rods. In order to achieve the control purpose we formulate the control model as the design problem of robust servo systems for distributed parameter reactor systems. Hence the total thermal power and the axial offset are chosen as outputs to be controlled. The control law is designed based upon finite-dimensional systems which are constructed by linearizing around steady states, approximating by the Galerkin approximate method and reducing dimensions via the singular perturbation method. From a computational point of view a simple computational algorithm to obtain an approximate solution of the steady state neutron balance is developed via the perturbation method. Some results of numerical simulations are represented to show effectiveness of the theory developed in this paper. Particularly it is shown that the designed servo systems are robust against model errors with the linearization and the model truncation. (author)

  15. Field Scale Spatial Modelling of Surface Soil Quality Attributes in Controlled Traffic Farming

    Science.gov (United States)

    Guenette, Kris; Hernandez-Ramirez, Guillermo

    2017-04-01

    The employment of controlled traffic farming (CTF) can yield improvements to soil quality attributes through the confinement of equipment traffic to tramlines with the field. There is a need to quantify and explain the spatial heterogeneity of soil quality attributes affected by CTF to further improve our understanding and modelling ability of field scale soil dynamics. Soil properties such as available nitrogen (AN), pH, soil total nitrogen (STN), soil organic carbon (SOC), bulk density, macroporosity, soil quality S-Index, plant available water capacity (PAWC) and unsaturated hydraulic conductivity (Km) were analysed and compared among trafficked and un-trafficked areas. We contrasted standard geostatistical methods such as ordinary kriging (OK) and covariate kriging (COK) as well as the hybrid method of regression kriging (ROK) to predict the spatial distribution of soil properties across two annual cropland sites actively employing CTF in Alberta, Canada. Field scale variability was quantified more accurately through the inclusion of covariates; however, the use of ROK was shown to improve model accuracy despite the regression model composition limiting the robustness of the ROK method. The exclusion of traffic from the un-trafficked areas displayed significant improvements to bulk density, macroporosity and Km while subsequently enhancing AN, STN and SOC. The ability of the regression models and the ROK method to account for spatial trends led to the highest goodness-of-fit and lowest error achieved for the soil physical properties, as the rigid traffic regime of CTF altered their spatial distribution at the field scale. Conversely, the COK method produced the most optimal predictions for the soil nutrient properties and Km. The use of terrain covariates derived from light ranging and detection (LiDAR), such as of elevation and topographic position index (TPI), yielded the best models in the COK method at the field scale.

  16. Experimental substantiation of separation techniques of lead and uranium microamounts using isotopic dilution method as control method

    International Nuclear Information System (INIS)

    Agapova, A.A.; Shcherbinina, N.K.

    1983-01-01

    Methods,ensuring at low levels of contamination a high degree of lead and uranium microamount separation from solutions of geological samples, have been selected and subjected to the detailed testing. The method of isotope dilution, , combining high accuracy and sensitivity of determinations, is used as the main control methods, is used as the main control method. Using the method, processe es of uranium extpaction are traced, special attention is paid to the detailed description of lead extraction at all the stages of the methods selected. Opera ations of ion exchange for lead and uranium in microcolumns with the Bio-Rad r sin are considered, as well as operations of lead electrolytic separation. The chemical procedures suggested permit to solve one of the main methodical tasks f sample preparation, containing microgram amounts of lead and uranium, for high h-prcision measurement of their isotope composition using mass-spectrometric method

  17. Learning of Temporal and Spatial Movement Aspects: A Comparison of Four Types of Haptic Control and Concurrent Visual Feedback.

    Science.gov (United States)

    Rauter, Georg; Sigrist, Roland; Riener, Robert; Wolf, Peter

    2015-01-01

    In literature, the effectiveness of haptics for motor learning is controversially discussed. Haptics is believed to be effective for motor learning in general; however, different types of haptic control enhance different movement aspects. Thus, in dependence on the movement aspects of interest, one type of haptic control may be effective whereas another one is not. Therefore, in the current work, it was investigated if and how different types of haptic controllers affect learning of spatial and temporal movement aspects. In particular, haptic controllers that enforce active participation of the participants were expected to improve spatial aspects. Only haptic controllers that provide feedback about the task's velocity profile were expected to improve temporal aspects. In a study on learning a complex trunk-arm rowing task, the effect of training with four different types of haptic control was investigated: position control, path control, adaptive path control, and reactive path control. A fifth group (control) trained with visual concurrent augmented feedback. As hypothesized, the position controller was most effective for learning of temporal movement aspects, while the path controller was most effective in teaching spatial movement aspects of the rowing task. Visual feedback was also effective for learning temporal and spatial movement aspects.

  18. Grouting aid for controlling the separation of water for cement grout for grouting vertical tendons in nuclear concrete pressure vessels

    International Nuclear Information System (INIS)

    Schupack, M.

    1976-01-01

    Considerable testing and development work has led to grouting procedures which can successfully grout 60 m and taller tendons in containment structures. The exaggerated water separation phenomena of strand tendons can be controlled by chemical admixtures using proper mixing and pumping procedures. Experience with both vertical six-bar tendons and large capacity strand type tendons are described. History, development work, characteristics of grout using the admixtures, mixing and pumping procedure, full scale tests and practical applications are included. (author)

  19. LES of High-Reynolds-Number Coanda Flow Separating from a Rounded Trailing Edge of a Circulation Control Airfoil

    Science.gov (United States)

    Nichino, Takafumi; Hahn, Seonghyeon; Shariff, Karim

    2010-01-01

    This slide presentation reviews the Large Eddy Simulation of a high reynolds number Coanda flow that is separated from a round trailing edge of a ciruclation control airfoil. The objectives of the study are: (1) To investigate detailed physics (flow structures and statistics) of the fully turbulent Coanda jet applied to a CC airfoil, by using LES (2) To compare LES and RANS results to figure out how to improve the performance of existing RANS models for this type of flow.

  20. Floral organ abscission peptide IDA and its HAE/HSL2 receptors control cell separation during lateral root emergence

    OpenAIRE

    Kumpf, Robert P.; Shi, Chun-Lin; Larrieu, Antoine; Stø, Ida Myhrer; Butenko, Melinka A.; Péret, Benjamin; Riiser, Even Sannes; Bennett, Malcolm J.; Aalen, Reidunn B.

    2013-01-01

    Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LI...

  1. Dynamic performances of wet turbine and steam-separator-superheater and their mathematical simulation as objects of temperature control

    International Nuclear Information System (INIS)

    Golovach, E.A.

    1985-01-01

    A mathematical model of a turbine and steam-separator-superheater (SSS) as applied to solution of the tasks of steam temperature regulaton after SSS has been developed. SSS as objects of steam temperature control are considerably less inertial, than intermediate superheaters (IS) of power units in thermal power plants, since for typical SSS and IS considered the duration of transition process according to steam temperature after SSS is 5-10 times loweA than for IS

  2. Final Technical Report - Consolidating Biomass Pretreatment with Saccharification by Resolving the Spatial Control Mechanisms of Fungi

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, Jonathan [Univ. of Minnesota, Minneapolis, MN (United States)

    2017-07-06

    Consolidated bioprocessing (CBP) of lignocellulose combines enzymatic sugar release (saccharification) with fermentation, but pretreatments remain separate and costly. In nature, lignocellulose-degrading brown rot fungi consolidate pretreatment and saccharification, likely using spatial gradients to partition these incompatible reactions. With the field of biocatalysis maturing, reaction partitioning is increasingly reproducible for commercial use. Therefore, my goal was to resolve the reaction partitioning mechanisms of brown rot fungi so that they can be applied to bioconversion of lignocellulosic feedstocks. Brown rot fungi consolidate oxidative pretreatments with saccharification and are a focus for biomass refining because 1) they attain >99% sugar yield without destroying lignin, 2) they use a simplified cellulase suite that lacks exoglucanase, and 3) their non-enzymatic pretreatment is facilitative and may be accelerated. Specifically, I hypothesized that during brown rot, oxidative pretreatments occur ahead of enzymatic saccharification, spatially, and the fungus partitions these reactions using gradients in pH, lignin reactivity, and plant cell wall porosity. In fact, we found three key results during these experiments for this work: 1) Brown rot fungi have an inducible cellulase system, unlike previous descriptions of a constitutive mechanism. 2) The induction of cellulases is delayed until there is repression of oxidatively-linked genes, allowing the brown rot fungi to coordinate two incompatible reactions (oxidative pretreatment with enzymatic saccharification, to release wood sugars) in the same pieces of wood. 3) This transition is mediated by the same wood sugar, cellobiose, released by the oxidative pretreatment step. Collectively, these findings have been published in excellent journal outlets and have been presented at conferences around the United States, and they offer clear targets for gene discovery en route to making biofuels and biochemicals

  3. A neuro-fuzzy controller for xenon spatial oscillations in load-following operation

    Energy Technology Data Exchange (ETDEWEB)

    Na, Man Gyun [Chosun University, Kwangju (Korea, Republic of); Upadhyaya, Belle R. [The University of Tennessee, Knoxville (United States)

    1997-12-31

    A neuro-fuzzy control algorithm is applied for xenon spatial oscillations in a pressurized water reactor. The consequent and antecedent parameters of the fuzzy rules are tuned by the gradient descent method. The reactor model used for computer simulations is a two-point xenon oscillation model. The reactor core is axially divided into two regions and each region has one input and one output and is coupled with the other region. The interaction between the regions of the reactor core is treated by a decoupling scheme. This proposed control method exhibits very responses to a step or a ramp change of target axial offest without any residual flux oscillations. 9 refs., 5 figs. (Author)

  4. Magnetogenetic control of protein gradients inside living cells with high spatial and temporal resolution.

    Science.gov (United States)

    Etoc, Fred; Vicario, Chiara; Lisse, Domenik; Siaugue, Jean-Michel; Piehler, Jacob; Coppey, Mathieu; Dahan, Maxime

    2015-05-13

    Tools for controlling the spatial organization of proteins are a major prerequisite for deciphering mechanisms governing the dynamic architecture of living cells. Here, we have developed a generic approach for inducing and maintaining protein gradients inside living cells by means of biofunctionalized magnetic nanoparticles (MNPs). For this purpose, we tailored the size and surface properties of MNPs in order to ensure unhindered mobility in the cytosol. These MNPs with a core diameter below 50 nm could be rapidly relocalized in living cells by exploiting biased diffusion at weak magnetic forces in the femto-Newton range. In combination with MNP surface functionalization for specific in situ capturing of target proteins as well as efficient delivery into the cytosplasm, we here present a comprehensive technology for controlling intracellular protein gradients with a temporal resolution of a few tens of seconds.

  5. A neuro-fuzzy controller for xenon spatial oscillations in load-following operation

    Energy Technology Data Exchange (ETDEWEB)

    Na, Man Gyun [Chosun University, Kwangju (Korea, Republic of); Upadhyaya, Belle R [The University of Tennessee, Knoxville (United States)

    1998-12-31

    A neuro-fuzzy control algorithm is applied for xenon spatial oscillations in a pressurized water reactor. The consequent and antecedent parameters of the fuzzy rules are tuned by the gradient descent method. The reactor model used for computer simulations is a two-point xenon oscillation model. The reactor core is axially divided into two regions and each region has one input and one output and is coupled with the other region. The interaction between the regions of the reactor core is treated by a decoupling scheme. This proposed control method exhibits very responses to a step or a ramp change of target axial offest without any residual flux oscillations. 9 refs., 5 figs. (Author)

  6. The TOR Signaling Pathway in Spatial and Temporal Control of Cell Size and Growth

    Directory of Open Access Journals (Sweden)

    Suam Gonzalez

    2017-06-01

    Full Text Available Cell size is amenable by genetic and environmental factors. The highly conserved nutrient-responsive Target of Rapamycin (TOR signaling pathway regulates cellular metabolic status and growth in response to numerous inputs. Timing and duration of TOR pathway activity is pivotal for both cell mass built up as well as cell cycle progression and is controlled and fine-tuned by the abundance and quality of nutrients, hormonal signals, growth factors, stress, and oxygen. TOR kinases function within two functionally and structurally discrete multiprotein complexes, TORC1 and TORC2, that are implicated in temporal and spatial control of cell size and growth respectively; however, recent data indicate that such functional distinctions are much more complex. Here, we briefly review roles of the two complexes in cellular growth and cytoarchitecture in various experimental model systems.

  7. Sport Skill-Specific Expertise Biases Sensory Integration for Spatial Referencing and Postural Control.

    Science.gov (United States)

    Thalassinos, Michalis; Fotiadis, Giorgos; Arabatzi, Fotini; Isableu, Brice; Hatzitaki, Vassilia

    2017-09-15

    The authors asked how sport expertise modulates visual field dependence and sensory reweighting for controlling posture. Experienced soccer athletes, ballet dancers, and nonathletes performed (a) a Rod and Frame test and (b) a 100-s bipedal stance task during which vision and proprioception were successively or concurrently disrupted in 20-s blocks. Postural adaptation was assessed in the mean center of pressure displacement, root mean square of center of pressure velocity and ankle muscles integrated electromyography activity. Soccer athletes were more field dependent than were nonathletes. During standing, dancers were more destabilized by vibration and required more time to reweigh sensory information compared with the other 2 groups. These findings reveal a sport skill-specific bias in the reweighing of sensory inputs for spatial orientation and postural control.

  8. Control of alpha particle transport by spatially inhomogeneous ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Chang, C.S.; Imre, K.; Weitzner, H.; Colestock, P.

    1990-02-01

    Control of the radial alpha particle transport by using Ion Cyclotron Range of Frequency waves is investigated in a large-aspect-ratio tokamak geometry. It is shown that spatially inhomogeneous ICRF-wave energy with properly selected frequencies and wave numbers can induce fast convective transport of alpha particles at the speed of order υ alpha ∼ (P RF /n α ε 0 ) ρ p , where P RF is the ICRF-wave power density, n α is the alpha density, ε 0 is the alpha birth energy, and ρ p is the poloidal gyroradius of alpha particles at the birth energy. Application to ITER plasmas is studied and possible antenna designs to control alpha particle flux are discussed. 8 refs., 3 figs

  9. Knowledge base expert system control of spatial xenon oscillations in pressurized water reactors

    International Nuclear Information System (INIS)

    Alten, S.

    1992-01-01

    Nuclear reactor operators are required to pay special attention to spatial xenon oscillations during the load-follow operation of pressurized water reactors. They are expected to observe the axial offset of the core, and to estimate the correct time and amount of necessary control action based on heuristic rules given in axial xenon oscillations are knowledge intensive, and heuristic in nature. An expert system, ACES (Axial offset Control using Expert Systems) is developed to implement a heuristic constant axial offset control procedure to aid reactor operators in increasing the plant reliability by reducing the human error component of the failure probability. ACES is written in a production system language, OPS5, based on the forward chaining algorithm. It samples reactor data with a certain time interval in terms of measurable parameters, such as the power, period, and the axial offset of the core. It then processes the core status utilizing a set of equations which are used in a back of the envelope calculations by domain experts. Heuristic rules of ACES identify the control variable to be used among the full and part length control rods and boron concentration, while a knowledge base is used to determine the amount of control. ACES is designed as a set of generic rules to avoid reducing the system into a set of patterns. Instead ACES evaluates the system, determines the necessary corrective actions in terms of reactivity insertion, and provides this reactivity insertion using the control variables. The amount of control action is determined using a knowledge base which consists of the differential rod worth curves, and the boron reactivity worth of a given reactor. Having the reactor dependent parameters in its knowledge base, ACES is applicable to an arbitrary reactor for axial offset control purposes

  10. Wind tunnel experiments on flow separation control of an Unmanned Air Vehicle by nanosecond discharge plasma aerodynamic actuation

    International Nuclear Information System (INIS)

    Chen Kang; Liang Hua

    2016-01-01

    Plasma flow control (PFC) is a new kind of active flow control technology, which can improve the aerodynamic performances of aircrafts remarkably. The flow separation control of an unmanned air vehicle (UAV) by nanosecond discharge plasma aerodynamic actuation (NDPAA) is investigated experimentally in this paper. Experimental results show that the applied voltages for both the nanosecond discharge and the millisecond discharge are nearly the same, but the current for nanosecond discharge (30 A) is much bigger than that for millisecond discharge (0.1 A). The flow field induced by the NDPAA is similar to a shock wave upward, and has a maximal velocity of less than 0.5 m/s. Fast heating effect for nanosecond discharge induces shock waves in the quiescent air. The lasting time of the shock waves is about 80 μs and its spread velocity is nearly 380 m/s. By using the NDPAA, the flow separation on the suction side of the UAV can be totally suppressed and the critical stall angle of attack increases from 20° to 27° with a maximal lift coefficient increment of 11.24%. The flow separation can be suppressed when the discharge voltage is larger than the threshold value, and the optimum operation frequency for the NDPAA is the one which makes the Strouhal number equal one. The NDPAA is more effective than the millisecond discharge plasma aerodynamic actuation (MDPAA) in boundary layer flow control. The main mechanism for nanosecond discharge is shock effect. Shock effect is more effective in flow control than momentum effect in high speed flow control. (paper)

  11. Microphase Separation Controlled beta-Sheet Crystallization Kinetics in Fibrous Proteins

    International Nuclear Information System (INIS)

    Hu, X.; Lu, Q.; Kaplan, D.; Cebe, P.

    2009-01-01

    Silk is a naturally occurring fibrous protein with a multiblock chain architecture. As such, it has many similarities with synthetic block copolymers, including the possibility for e-sheet crystallization restricted within the crystallizable blocks. The mechanism of isothermal crystallization kinetics of e-sheet crystals in silk multiblock fibrous proteins is reported in this study. Kinetics theories, such as Avrami analysis which was established for studies of synthetic polymer crystal growth, are for the first time extended to investigate protein self-assembly in e-sheet rich Bombyx mori silk fibroin samples, using time-resolved Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and synchrotron real-time wide-angle X-ray scattering (WAXS). The Avrami exponent, n, was close to 2 for all methods and crystallization temperatures, indicating formation of e-sheet crystals in silk proteins is different from the 3-D spherulitic crystal growth found in synthetic polymers. Observations by scanning electron microscopy support the view that the protein structures vary during the different stages of crystal growth, and show a microphase separation pattern after chymotrypsin enzyme biodegradation. We present a model to explain the crystallization of the multiblock silk fibroin protein, by analogy to block copolymers: crystallization of e-sheets occurs under conditions of geometrical restriction caused by phase separation of the crystallizable and uncrystallizable blocks. This crystallization model could be widely applicable in other proteins with multiblock (i.e., crystallizable and noncrystallizable) domains.

  12. Experiences in control system design aided by interactive computer programs: temperature control of the laser isotope separation vessel

    International Nuclear Information System (INIS)

    Gavel, D.T.; Pittenger, L.C.; McDonald, J.S.; Cramer, P.G.; Herget, C.J.

    1985-01-01

    A robust control system has been designed to regulate temperature in a vacuum vessel. The thermodynamic process is modeled by a set of nonlinear, implicit differential equations. The control design and analysis task exercised many of the computer-aided control systems design software packages, including MATLAB, DELIGHT, and LSAP. The working environment is a VAX computer. Advantages and limitations of the software and environment, and the impact on final controller design is discussed

  13. Experiences in control system design aided by interactive computer programs: Temperature control of the laser isotope separation vessel

    Science.gov (United States)

    Gavel, D. T.; Pittenger, L. C.; McDonald, J. S.; Cramer, P. G.; Herget, C. J.

    A robust control system has been designed to regulate temperature in a vacuum vessel. The thermodynamic process is modeled by a set of nonlinear, implicit differential equations. The control design and analysis task exercised many of the computer-aided control systems design software packages, including MATLAB, DELIGHT, AND LSAP. The working environment is a VAX computer. Advantages and limitations of the software and environment, and the impact on final controller design is discussed.

  14. Active Control of Thermal Convection in a Rectangular Loop by Changing its Spatial Orientation

    Science.gov (United States)

    Bratsun, Dmitry A.; Krasnyakov, Ivan V.; Zyuzgin, Alexey V.

    2018-02-01

    The problem of the automatic control of the fluid flow in a rectangular convective loop heated from below is studied theoretically and experimentally. The control is performed by using a feedback subsystem which changes the convection regimes by introducing small discrete changes in the spatial orientation of the loop with respect to gravity. We focus on effects that arise when the feedback controller operates with an unavoidable time delay, which is cause by the thermal inertia of the medium. The mathematical model of the phenomenon is developed. The dynamic regimes of the convection in the thermosyphon loop under control are studied. It is shown that the proposed control method can successfully stabilize not only a no-motion state of the fluid, but also time-dependent modes of convection including the irregular fluid flow at high values of the Rayleigh number. It is shown that the excessive gain of the proportional feedback can result in oscillations in the loop orientation exciting the unsteady convection modes. The comparison of the experimental data obtained for dielectric oil and dodecane with theory is given, and their good agreement is demonstrated.

  15. Spatial control of cell attachment, proliferation, and differentiation using ion-beam induced thin films

    International Nuclear Information System (INIS)

    Tanaka, Toshiyuki; Suzuki, Yoshiaki

    2014-01-01

    Highlights: • Cellular films can be obtained ion-beam irradiation and cell culture. • Film shapes were controlled by patterned irradiation. • Cellular films were firmly attached each other. • Tubular constructions were fabricated by wide-patterned irradiation. • Nerve growth direction was controlled by varying the pattern widths. - Abstract: In this study, cellular films were fabricated by ion-beam irradiation into poly-L-lactic acid sheets and cell culture. The cellular film shapes can be controlled by pattern masks. We performed spatial cell patterning using three types of cells: fibroblasts, endothelial cells, and nerve-like cells. First, multi-layered cellular construct was fabricated by stacking fibroblast cellular films. When three cellular films were stacked and incubated, these films firmly attached to each other. Second, tubular constructs were fabricated by endothelial cell culture on linearly patterned surfaces with wide widths of 80, 120, 160, and 200 μm. The patterned cellular films were rounded into vessel-like structure. The diameters of the constructs depend upon the pattern widths. Finally, we controlled cell attachment and nerve growth of nerve-like cells by using linearly patterned surfaces with narrow widths of 10, 30, and 50 μm. Nerve growth direction was controlled by varying the pattern widths. In the case of 10 μm, the attached cells and nerve growth were straight on the patterned thin films. These cell patterning techniques are expected to have applications in tissue engineering, cell transplantation, and in vitro tissue modeling

  16. Biocrust spatial distribution at landscape scale is strongly controlled by terrain attributes: Topographic thresholds for colonization

    Science.gov (United States)

    Raúl Román Fernández, José; Rodríguez-Caballero, Emilio; Chamizo de la Piedra, Sonia; Roncero Ramos, Bea; Cantón Castilla, Yolanda

    2017-04-01

    Biological soil crusts (biocrusts) are spatially variable components of soil. Whereas biogeographic, climatic or soil properties drive biocrust distribution from regional to global scales, biocrust spatial distribution within the landscape is controlled by topographic forces that create specific microhabitats that promote or difficult biocrust growth. By knowing which are the variables that control biocrust distribution and their individual effect we can establish the abiotic thresholds that limit natural biocrust colonization on different environments, which may be very useful for designing soil restoration programmes. The objective of this study was to analyse the influence of topographic-related variables in the distribution of different types of biocrust within a semiarid catchment where cyanobacteria and lichen dominated biocrust represent the most important surface components, El Cautivo experimental area (SE Spain). To do this, natural coverage of i) bare soil, ii) vegetation, iii) cyanobacteria-dominated soil crust and iv) lichen-dominated soil crust were measured on 70 experimental plots distributed across 23 transect (three 4.5 x 4.5 m plots per transect). Following that, we used a 1m x 1m DEM (Digital Elevation Model) of the study site obtained from a LiDAR point cloud to calculate different topographic variables such as slope gradient, length slope (LS) factor (potential sediment transport index), potential incoming solar radiation, topographic wetness index (WI) and maximum flow accumulation. Canonical Correspondence Analysis was performed to infer the influence of each variable in the coverage of each class and thresholds of biocrust colonization were identified mathematically by means of linear regression analysis describing the relationship between each factor and biocrust cover. Our results show that the spatial distribution of cyanobacteria-dominated biocrust, which showed physiological and morphological adaptation to cope with drought and UVA

  17. How exciton-vibrational coherences control charge separation in the photosystem II reaction center.

    Science.gov (United States)

    Novoderezhkin, Vladimir I; Romero, Elisabet; van Grondelle, Rienk

    2015-12-14

    In photosynthesis absorbed sun light produces collective excitations (excitons) that form a coherent superposition of electronic and vibrational states of the individual pigments. Two-dimensional (2D) electronic spectroscopy allows a visualization of how these coherences are involved in the primary processes of energy and charge transfer. Based on quantitative modeling we identify the exciton-vibrational coherences observed in 2D photon echo of the photosystem II reaction center (PSII-RC). We find that the vibrations resonant with the exciton splittings can modify the delocalization of the exciton states and produce additional states, thus promoting directed energy transfer and allowing a switch between the two charge separation pathways. We conclude that the coincidence of the frequencies of the most intense vibrations with the splittings within the manifold of exciton and charge-transfer states in the PSII-RC is not occurring by chance, but reflects a fundamental principle of how energy conversion in photosynthesis was optimized.

  18. Phase separation of DMDBS from iPP, and controlled crystalline orientation

    Science.gov (United States)

    Sreenivas, K.; Kumaraswamy, Guruswamy; Basargekar, R. S.

    2012-02-01

    We report an unexpected dependence of DMDBS phase separation temperature on the molecular weight of the matrix isotactic polypropylene (iPP). DMDBS crystallizes out at lower temperatures for iPP with decreasing molecular weight (and correspondingly lower tacticity). This molecular weight dependence is unique to iPP, and is not observed for either syndiotactic PP or for random ethylene-PP copolymers. We show that thermodynamic Flory-type arguments are unable to rationalize the observed results. We also results on extrusion film casting of iPP containing DMDBS and show that flow-alignment of DMDBS networks template the orientation of PP crystals. The modulus and yield strength increase on addition of DMDBS, relative to the neat iPP. Tensile modulus and yield stress of drawn films increase with the degree of orientation, and we are able to achieve a substantial increase even at relatively low draw ratios.

  19. Strategies towards controlling strain-induced mesoscopic phase separation in manganite thin films

    Science.gov (United States)

    Habermeier, H.-U.

    2008-10-01

    Complex oxides represent a class of materials with a plethora of fascinating intrinsic physical functionalities. The intriguing interplay of charge, spin and orbital ordering in these systems superimposed by lattice effects opens a scientifically rewarding playground for both fundamental as well as application oriented research. The existence of nanoscale electronic phase separation in correlated complex oxides is one of the areas in this field whose impact on the current understanding of their physics and potential applications is not yet clear. In this paper this issue is treated from the point of view of complex oxide thin film technology. Commenting on aspects of complex oxide thin film growth gives an insight into the complexity of a reliable thin film technology for these materials. Exploring fundamentals of interfacial strain generation and strain accommodation paves the way to intentionally manipulate thin film properties. Furthermore, examples are given for an extrinsic continuous tuning of intrinsic electronic inhomogeneities in perovskite-type complex oxide thin films.

  20. Strategies towards controlling strain-induced mesoscopic phase separation in manganite thin films

    International Nuclear Information System (INIS)

    Habermeier, H-U

    2008-01-01

    Complex oxides represent a class of materials with a plethora of fascinating intrinsic physical functionalities. The intriguing interplay of charge, spin and orbital ordering in these systems superimposed by lattice effects opens a scientifically rewarding playground for both fundamental as well as application oriented research. The existence of nanoscale electronic phase separation in correlated complex oxides is one of the areas in this field whose impact on the current understanding of their physics and potential applications is not yet clear. In this paper this issue is treated from the point of view of complex oxide thin film technology. Commenting on aspects of complex oxide thin film growth gives an insight into the complexity of a reliable thin film technology for these materials. Exploring fundamentals of interfacial strain generation and strain accommodation paves the way to intentionally manipulate thin film properties. Furthermore, examples are given for an extrinsic continuous tuning of intrinsic electronic inhomogeneities in perovskite-type complex oxide thin films.

  1. Application of Decomposition Methodology to Solve Integrated Process Design and Controller Design Problems for Reactor-Separator-Recycle System

    DEFF Research Database (Denmark)

    Abd.Hamid, Mohd-Kamaruddin; Sin, Gürkan; Gani, Rafiqul

    2010-01-01

    This paper presents the integrated process design and controller design (IPDC) for a reactor-separator-recycle (RSR) system and evaluates a decomposition methodology to solve the IPDC problem. Accordingly, the IPDC problem is solved by decomposing it into four hierarchical stages: (i) pre...... the design of a RSR system involving consecutive reactions, A B -> C and shown to provide effective solutions that satisfy design, control and cost criteria. The advantage of the proposed methodology is that it is systematic, makes use of thermodynamic-process knowledge and provides valuable insights......-analysis, (ii) design analysis, (iii) controller design analysis, and (iv) final selection and verification. The methodology makes use of thermodynamic-process insights and the reverse design approach to arrive at the final process-controller design decisions. The developed methodology is illustrated through...

  2. Effect of Reynolds Number on Separation Bubbles on Controlled-Diffusion Compressor Blades in Cascade

    National Research Council Canada - National Science Library

    Hobson, Garth

    2001-01-01

    A detailed experimental investigation of second- generation, controlled-diffusion, compressor stator blades at an off-design inlet-flow angle was performed in a low-speed cascade wind tunnel primarily...

  3. Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: Toward controllable oil/water separation

    KAUST Repository

    Zhang, L.; Zhang, Z.; Wang, Peng

    2012-01-01

    Advanced materials with surfaces that have controllable oil wettability when submerged in aqueous media have great potential for various underwater applications. Here we have developed smart surfaces on commonly used materials, including non

  4. Improved control for distributed parameter systems with time-dependent spatial domains utilizing mobile sensor–actuator networks

    International Nuclear Information System (INIS)

    Zhang Jian-Zhong; Cui Bao-Tong; Zhuang Bo

    2017-01-01

    A guidance policy for controller performance enhancement utilizing mobile sensor–actuator networks (MSANs) is proposed for a class of distributed parameter systems (DPSs), which are governed by diffusion partial differential equations (PDEs) with time-dependent spatial domains. Several sufficient conditions for controller performance enhancement are presented. First, the infinite dimensional operator theory is used to derive an abstract evolution equation of the systems under some rational assumptions on the operators, and a static output feedback controller is designed to control the spatial process. Then, based on Lyapunov stability arguments, guidance policies for collocated and non-collocated MSANs are provided to enhance the performance of the proposed controller, which show that the time-dependent characteristic of the spatial domains can significantly affect the design of the mobile scheme. Finally, a simulation example illustrates the effectiveness of the proposed policy. (paper)

  5. Electrophysiological evidence for cognitive control during conflict processing in visual spatial attention.

    Science.gov (United States)

    Kehrer, Stefanie; Kraft, Antje; Irlbacher, Kerstin; Koch, Stefan P; Hagendorf, Herbert; Kathmann, Norbert; Brandt, Stephan A

    2009-11-01

    Event-related potentials were measured to investigate the role of visual spatial attention mechanisms in conflict processing. We suggested that a more difficult target selection leads to stronger attentional top-down control, thereby reducing the effects of arising conflicts. This hypothesis was tested by varying the selection difficulty in a location negative priming (NP) paradigm. The difficult task resulted in prolonged responses as compared to the easy task. A behavioral NP effect was only evident in the easy task. Psychophysiologically the easy task was associated with reduced parietal N1, enhanced frontocentral N2 and N2pc components and a prolonged P3 latency for the conflict as compared to the control condition. The N2pc effect was also obvious in the difficult task. Additionally frontocentral N2 amplitudes increased and latencies of N2pc and P3 were delayed compared to the easy task. The differences at frontocentral and parietal electrodes are consistent with previous studies ascribing activity in the prefrontal and parietal cortex as the source of top-down attentional control. Thus, we propose that stronger cognitive control is involved in the difficult task, resulting in a reduced behavioral NP conflict.

  6. Control of spatial xenon oscillations in pressurized water reactors via the Kalman filter

    International Nuclear Information System (INIS)

    Lin, C.; Lin, Y.J.

    1994-01-01

    A direct control method is developed to control the spatial xenon oscillations in pressurized water reactors. The xenon and iodine concentration difference between the top and bottom halves of the core is estimated by using the extended Kalman filter (EKF), which is a closed-loop estimation method. The measurement equation used in the observer is the axial offset measurement equation, which reflects the xenon unbalanced effect on the axial offset. Meanwhile, some of the coefficients of the observer are estimated on-line to reduce estimation error resulting from model error, i.e., simplified xenon and iodine dynamics. Therefore, the estimation can be guaranteed to be accurate, and the success of the estimation does not greatly depend on the accuracy of the observer model. The predicted one-step ahead xenon concentration, by using the EKF, was used to calculate the possible axial offset variation, and then the control rod motion was calculated to compensate for it. The simulation results show that the proposed method successfully controls the xenon oscillations

  7. Experimental Evaluation of a Mixed Controller That Amplifies Spatial Errors and Reduces Timing Errors

    Directory of Open Access Journals (Sweden)

    Laura Marchal-Crespo

    2017-06-01

    Full Text Available Research on motor learning suggests that training with haptic guidance enhances learning of the timing components of motor tasks, whereas error amplification is better for learning the spatial components. We present a novel mixed guidance controller that combines haptic guidance and error amplification to simultaneously promote learning of the timing and spatial components of complex motor tasks. The controller is realized using a force field around the desired position. This force field has a stable manifold tangential to the trajectory that guides subjects in velocity-related aspects. The force field has an unstable manifold perpendicular to the trajectory, which amplifies the perpendicular (spatial error. We also designed a controller that applies randomly varying, unpredictable disturbing forces to enhance the subjects’ active participation by pushing them away from their “comfort zone.” We conducted an experiment with thirty-two healthy subjects to evaluate the impact of four different training strategies on motor skill learning and self-reported motivation: (i No haptics, (ii mixed guidance, (iii perpendicular error amplification and tangential haptic guidance provided in sequential order, and (iv randomly varying disturbing forces. Subjects trained two motor tasks using ARMin IV, a robotic exoskeleton for upper limb rehabilitation: follow circles with an ellipsoidal speed profile, and move along a 3D line following a complex speed profile. Mixed guidance showed no detectable learning advantages over the other groups. Results suggest that the effectiveness of the training strategies depends on the subjects’ initial skill level. Mixed guidance seemed to benefit subjects who performed the circle task with smaller errors during baseline (i.e., initially more skilled subjects, while training with no haptics was more beneficial for subjects who created larger errors (i.e., less skilled subjects. Therefore, perhaps the high functional

  8. Role-separating ordering in social dilemmas controlled by topological frustration

    Science.gov (United States)

    Amaral, Marco A.; Perc, Matjaž; Wardil, Lucas; Szolnoki, Attila; da Silva Júnior, Elton J.; da Silva, Jafferson K. L.

    2017-03-01

    ``Three is a crowd" is an old proverb that applies as much to social interactions as it does to frustrated configurations in statistical physics models. Accordingly, social relations within a triangle deserve special attention. With this motivation, we explore the impact of topological frustration on the evolutionary dynamics of the snowdrift game on a triangular lattice. This topology provides an irreconcilable frustration, which prevents anticoordination of competing strategies that would be needed for an optimal outcome of the game. By using different strategy updating protocols, we observe complex spatial patterns in dependence on payoff values that are reminiscent to a honeycomb-like organization, which helps to minimize the negative consequence of the topological frustration. We relate the emergence of these patterns to the microscopic dynamics of the evolutionary process, both by means of mean-field approximations and Monte Carlo simulations. For comparison, we also consider the same evolutionary dynamics on the square lattice, where of course the topological frustration is absent. However, with the deletion of diagonal links of the triangular lattice, we can gradually bridge the gap to the square lattice. Interestingly, in this case the level of cooperation in the system is a direct indicator of the level of topological frustration, thus providing a method to determine frustration levels in an arbitrary interaction network.

  9. Spatial co-adaptation of cortical control columns in a micro-ECoG brain-computer interface

    Science.gov (United States)

    Rouse, A. G.; Williams, J. J.; Wheeler, J. J.; Moran, D. W.

    2016-10-01

    Objective. Electrocorticography (ECoG) has been used for a range of applications including electrophysiological mapping, epilepsy monitoring, and more recently as a recording modality for brain-computer interfaces (BCIs). Studies that examine ECoG electrodes designed and implanted chronically solely for BCI applications remain limited. The present study explored how two key factors influence chronic, closed-loop ECoG BCI: (i) the effect of inter-electrode distance on BCI performance and (ii) the differences in neural adaptation and performance when fixed versus adaptive BCI decoding weights are used. Approach. The amplitudes of epidural micro-ECoG signals between 75 and 105 Hz with 300 μm diameter electrodes were used for one-dimensional and two-dimensional BCI tasks. The effect of inter-electrode distance on BCI control was tested between 3 and 15 mm. Additionally, the performance and cortical modulation differences between constant, fixed decoding using a small subset of channels versus adaptive decoding weights using the entire array were explored. Main results. Successful BCI control was possible with two electrodes separated by 9 and 15 mm. Performance decreased and the signals became more correlated when the electrodes were only 3 mm apart. BCI performance in a 2D BCI task improved significantly when using adaptive decoding weights (80%-90%) compared to using constant, fixed weights (50%-60%). Additionally, modulation increased for channels previously unavailable for BCI control under the fixed decoding scheme upon switching to the adaptive, all-channel scheme. Significance. Our results clearly show that neural activity under a BCI recording electrode (which we define as a ‘cortical control column’) readily adapts to generate an appropriate control signal. These results show that the practical minimal spatial resolution of these control columns with micro-ECoG BCI is likely on the order of 3 mm. Additionally, they show that the combination and

  10. Microscale architecture in biomaterial scaffolds for spatial control of neural cell behavior

    Science.gov (United States)

    Meco, Edi; Lampe, Kyle J.

    2018-02-01

    Biomaterial scaffolds mimic aspects of the native central nervous system (CNS) extracellular matrix (ECM) and have been extensively utilized to influence neural cell (NC) behavior in in vitro and in vivo settings. These biomimetic scaffolds support NC cultures, can direct the differentiation of NCs, and have recapitulated some native NC behavior in an in vitro setting. However, NC transplant therapies and treatments used in animal models of CNS disease and injury have not fully restored functionality. The observed lack of functional recovery occurs despite improvements in transplanted NC viability when incorporating biomaterial scaffolds and the potential of NC to replace damaged native cells. The behavior of NCs within biomaterial scaffolds must be directed in order to improve the efficacy of transplant therapies and treatments. Biomaterial scaffold topography and imbedded bioactive cues, designed at the microscale level, can alter NC phenotype, direct migration, and differentiation. Microscale patterning in biomaterial scaffolds for spatial control of NC behavior has enhanced the capabilities of in vitro models to capture properties of the native CNS tissue ECM. Patterning techniques such as lithography, electrospinning and 3D bioprinting can be employed to design the microscale architecture of biomaterial scaffolds. Here, the progress and challenges of the prevalent biomaterial patterning techniques of lithography, electrospinning, and 3D bioprinting are reported. This review analyzes NC behavioral response to specific microscale topographical patterns and spatially organized bioactive cues.

  11. Microscale Architecture in Biomaterial Scaffolds for Spatial Control of Neural Cell Behavior

    Directory of Open Access Journals (Sweden)

    Edi Meco

    2018-02-01

    Full Text Available Biomaterial scaffolds mimic aspects of the native central nervous system (CNS extracellular matrix (ECM and have been extensively utilized to influence neural cell (NC behavior in in vitro and in vivo settings. These biomimetic scaffolds support NC cultures, can direct the differentiation of NCs, and have recapitulated some native NC behavior in an in vitro setting. However, NC transplant therapies and treatments used in animal models of CNS disease and injury have not fully restored functionality. The observed lack of functional recovery occurs despite improvements in transplanted NC viability when incorporating biomaterial scaffolds and the potential of NC to replace damaged native cells. The behavior of NCs within biomaterial scaffolds must be directed in order to improve the efficacy of transplant therapies and treatments. Biomaterial scaffold topography and imbedded bioactive cues, designed at the microscale level, can alter NC phenotype, direct migration, and differentiation. Microscale patterning in biomaterial scaffolds for spatial control of NC behavior has enhanced the capabilities of in vitro models to capture properties of the native CNS tissue ECM. Patterning techniques such as lithography, electrospinning and three-dimensional (3D bioprinting can be employed to design the microscale architecture of biomaterial scaffolds. Here, the progress and challenges of the prevalent biomaterial patterning techniques of lithography, electrospinning, and 3D bioprinting are reported. This review analyzes NC behavioral response to specific microscale topographical patterns and spatially organized bioactive cues.

  12. Statistical process control: separating signal from noise in emergency department operations.

    Science.gov (United States)

    Pimentel, Laura; Barrueto, Fermin

    2015-05-01

    Statistical process control (SPC) is a visually appealing and statistically rigorous methodology very suitable to the analysis of emergency department (ED) operations. We demonstrate that the control chart is the primary tool of SPC; it is constructed by plotting data measuring the key quality indicators of operational processes in rationally ordered subgroups such as units of time. Control limits are calculated using formulas reflecting the variation in the data points from one another and from the mean. SPC allows managers to determine whether operational processes are controlled and predictable. We review why the moving range chart is most appropriate for use in the complex ED milieu, how to apply SPC to ED operations, and how to determine when performance improvement is needed. SPC is an excellent tool for operational analysis and quality improvement for these reasons: 1) control charts make large data sets intuitively coherent by integrating statistical and visual descriptions; 2) SPC provides analysis of process stability and capability rather than simple comparison with a benchmark; 3) SPC allows distinction between special cause variation (signal), indicating an unstable process requiring action, and common cause variation (noise), reflecting a stable process; and 4) SPC keeps the focus of quality improvement on process rather than individual performance. Because data have no meaning apart from their context, and every process generates information that can be used to improve it, we contend that SPC should be seriously considered for driving quality improvement in emergency medicine. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Piezoelectric self-sensing actuator for active vibration control of motorized spindle based on adaptive signal separation

    Science.gov (United States)

    He, Ye; Chen, Xiaoan; Liu, Zhi; Qin, Yi

    2018-06-01

    The motorized spindle is the core component of CNC machine tools, and the vibration of it reduces the machining precision and service life of the machine tools. Owing to the fast response, large output force, and displacement of the piezoelectric stack, it is often used as the actuator in the active vibration control of the spindle. A piezoelectric self-sensing actuator (SSA) can reduce the cost of the active vibration control system and simplify the structure by eliminating the use of a sensor, because a SSA can have both actuating and sensing functions at the same time. The signal separation method of a SSA based on a bridge circuit is widely applied because of its simple principle and easy implementation. However, it is difficult to maintain dynamic balance of the circuit. Prior research has used adaptive algorithm to balance of the bridge circuit on the flexible beam dynamically, but those algorithms need no correlation between sensing and control voltage, which limit the applications of SSA in the vibration control of the rotor-bearing system. Here, the electromechanical coupling model of the piezoelectric stack is established, followed by establishment of the dynamic model of the spindle system. Next, a new adaptive signal separation method based on the bridge circuit is proposed, which can separate relative small sensing voltage from related mixed voltage adaptively. The experimental results show that when the self-sensing signal obtained from the proposed method is used as a displacement signal, the vibration of the motorized spindle can be suppressed effectively through a linear quadratic Gaussian (LQG) algorithm.

  14. An efficient and rigorous thermodynamic library and optimal-control of a cryogenic air separation unit

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp

    2017-01-01

    -linear model based control to achieve optimal techno-economic performance. Accordingly, this work presents a computationally efficient and novel approach for solving a tray-by-tray equilibrium model and its implementation for open-loop optimal-control of a cryogenic distillation column. Here, the optimisation...... objective is to reduce the cost of compression in a volatile electricity market while meeting the production requirements, i.e. product flow rate and purity. This model is implemented in Matlab and uses the ThermoLib rigorous thermodynamic library. The present work represents a first step towards plant...

  15. Control properties of hybrid distillation processes for the separation of biobutanol

    DEFF Research Database (Denmark)

    Sánchez-Ramírez, Eduardo; Alcocer-García, Heriberto; Quiroz-Ramírez, Juan José

    2017-01-01

    value decomposition technique and a closed-loop dynamic analysis was performed on several hybrid distillation processes including conventional, thermally coupled, thermodynamically equivalent and intensified designs. The results indicated that under the closed-loop control policy, an intensified design...... which is integrated for only two distillation columns instead of three distillation columns, showed good dynamic properties. In addition, thermally coupled sequence A showed better control properties under open-loop analysis. CONCLUSIONS: Using both SVD analysis and closed-loop tests the dynamics...

  16. Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration

    Energy Technology Data Exchange (ETDEWEB)

    Herz, A., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Rossberg, D.; Hentschel, M.; Theska, F.; Wang, D., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Schaaf, P. [Department of Materials for Electronics and Electrical Engineering, Institute of Materials Science and Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, D-98693 Ilmenau (Germany); Friák, M. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic); Central European Institute of Technology, CEITEC MU, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic); Holec, D. [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, A-8700 Leoben (Austria); Šob, M. [Central European Institute of Technology, CEITEC MU, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic); Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic); Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno (Czech Republic); Schneeweiss, O. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic)

    2015-08-17

    Solid-state dewetting is used to fabricate supersaturated, submicron-sized Au-Ni solid solution particles out of thin Au/Ni bilayers by means of a rapid thermal annealing technique. Phase separation in such particles is studied with respect to their equilibrium crystal (or Wulff) shape by subsequent annealing at elevated temperature. It is found that (100) faceting planes of the equilibrated particles are enriched with Ni and (111) faces with Au. Both phases are considered by quantum-mechanical calculations in combination with an error-reduction scheme that was developed to compensate for a missing exchange-correlation potential that would reliably describe both Au and Ni. The observed phase configuration is then related to the minimization of strongly anisotropic elastic energies of Au- and Ni-rich phases and results in a rather unique nanoparticle composite state that is characterized by nearly uniform value of elastic response to epitaxial strains all over the faceted surface. The same conclusion is yielded also by evaluating bi-axial elastic moduli when employing interpolated experimental elastic constants. This work demonstrates a useful route for studying features of physical metallurgy at the mesoscale.

  17. Cyclotron production, radiochemical separation and quality control of platinum radiotracers for toxicological studies

    International Nuclear Information System (INIS)

    Bonardi, M.; Birattari, C.; Groppi, F.; Arginelli, D.; Gini, L.; Gallorini, M.

    1998-01-01

    The increasing concentration of Pt, Pd and Rh in the environment is mainly due to the release of these elements from the catalytic converters of the motorvehicles. This situation makes it necessary to carry out metallotoxicological experiments on both cell cultures and laboratory animals, in order to assess their impact on living organisms after a Long Term and Low Level Exposure (LLE). Both nuclear reactions nat Ir(p,xn) and nat Os(α,xn) were investigated in the energy range up to 45 MeV for protons and 38 MeV for alpha-particles, in order to optimize the irradiation parameters for the production of 188,189,191 Pt. Several sets of thin- and thick-target excitation functions were determined experimentally by cyclotron irradiation at both Milano and Ispra cyclotrons. This paper reports the irradiation parameters studied and adopted and two radiochemical procedures for the separation of radio-Pt from an Os target, as well as from ruthenium, iridium and gold impurities. These procedures were used to obtain very high specific activity Pt radionuclides in No Carrier Added (NCA) form. Radionuclidic, radiochemical and chemical purity measurements were carried out by the use of several techniques like γ-spectrometry, ion-exchange radio-chromatography, atomic absorption spectrometry and neutron activation analysis. (author)

  18. On the flow around Glauert-Goldschmied body in the narrow channel and separation control strategy

    Czech Academy of Sciences Publication Activity Database

    Procházka, Pavel P.; Uruba, Václav

    2016-01-01

    Roč. 16, č. 1 (2016), s. 643-644 ISSN 1617-7061 R&D Projects: GA ČR(CZ) GP14-25354P Institutional support: RVO:61388998 Keywords : PIV * active flow control * Glauert-Goldschmied body Subject RIV: BK - Fluid Dynamics http://onlinelibrary.wiley.com/doi/10.1002/pamm.201610310/full

  19. Spatial distribution of groundwater recharge and base flow: Assessment of controlling factors

    Directory of Open Access Journals (Sweden)

    Z. Zomlot

    2015-09-01

    New hydrological insights for the region: The average resulting recharge is 235 mm/year and occurs mainly in winter. The overall moderate correlation between base flow estimates and modeled recharge rates indicates that base flow is a reasonable proxy of recharge. Groundwater recharge variation was explained in order of importance by precipitation, soil texture and vegetation cover; while base flow variation was strongly controlled by vegetation cover and groundwater depth. The results of this study highlight the important role of spatial variables in estimation of recharge and base flow. In addition, the prominent role of vegetation makes clear the potential importance of land-use changes on recharge and hence the need to include a proper strategy for land-use change in sustainable management of groundwater resources.

  20. Spatial resolution in depth-controlled surface sensitive x-ray techniques

    International Nuclear Information System (INIS)

    Yun, W.B.; Viccaro, P.J.

    1992-01-01

    The spatial resolution along the surface normal and the total depth probed are two important parameters in depth-controlled surface sensitive X-ray techniques employing grazing incidence geometry. The two parameters are analyzed in terms of optical properties (refractive indices) of the media involved and parameters of the incident X-ray beam: beam divergence, X-ray energy, and spectral bandwidth. We derive analytical expressions of the required beam divergence and spectral bandwidth of the incident beam as a function of the two parameters. Sample calculations are made for X-ray energies between 0.1 and 100 keV and for solid Be, Cu, and Au, representing material matrices consisting of low, medium, and high atomic number elements. A brief discussion on obtaining the required beam divergence and spectral bandwidth from present X-ray sources and optics is given

  1. Single Cell Responses to Spatially Controlled Photosensitized Production of Extracellular Singlet Oxygen

    DEFF Research Database (Denmark)

    Pedersen, Brian Wett; Sinks, Louise E.; Breitenbach, Thomas

    2011-01-01

    The response of individual HeLa cells to extracellularly produced singlet oxygen was examined. The spatial domain of singlet oxygen production was controlled using the combination of a membrane-impermeable Pd porphyrin-dendrimer, which served as a photosensitizer, and a focused laser, which served...... to localize the sensitized production of singlet oxygen. Cells in close proximity to the domain of singlet oxygen production showed morphological changes commonly associated with necrotic cell death. The elapsed post-irradiation “waiting period” before necrosis became apparent depended on (a) the distance...... between the cell membrane and the domain irradiated, (b) the incident laser fluence and, as such, the initial concentration of singlet oxygen produced, and (c) the lifetime of singlet oxygen. The data imply that singlet oxygen plays a key role in this process of light-induced cell death. The approach...

  2. Topographic and spatial controls of palm species distributions in a montane rain forest, southern Ecuador

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Harlev, D.; Sørensen, M.M.

    2009-01-01

    The northern Andes harbour a flora that is as species-rich or even richer than the 18-times larger lowland Amazon basin. Gaining an understanding of how the high species richness of the Andean region is generated and maintained is therefore of particular interest. Environmental sorting due......). Mantel tests and indicator species analysis showed that both topography and spatial location imposed strong controls on palm species distributions at the study site. Our results suggest that species distributions in the studied montane forest landscape were partly determined by the species' habitat...... distributions at the study site. Other factors must also be involved, notably wind-exposure and hydrology, as discussed for lowland palm communities. Our results show that to understand plant community assembly in the tropical montane forests of the Andes it is too simple to focus just on environmental sorting...

  3. Electrical Programming of Soft Matter: Using Temporally Varying Electrical Inputs To Spatially Control Self Assembly.

    Science.gov (United States)

    Yan, Kun; Liu, Yi; Zhang, Jitao; Correa, Santiago O; Shang, Wu; Tsai, Cheng-Chieh; Bentley, William E; Shen, Jana; Scarcelli, Giuliano; Raub, Christopher B; Shi, Xiao-Wen; Payne, Gregory F

    2018-02-12

    The growing importance of hydrogels in translational medicine has stimulated the development of top-down fabrication methods, yet often these methods lack the capabilities to generate the complex matrix architectures observed in biology. Here we show that temporally varying electrical signals can cue a self-assembling polysaccharide to controllably form a hydrogel with complex internal patterns. Evidence from theory and experiment indicate that internal structure emerges through a subtle interplay between the electrical current that triggers self-assembly and the electrical potential (or electric field) that recruits and appears to orient the polysaccharide chains at the growing gel front. These studies demonstrate that short sequences (minutes) of low-power (∼1 V) electrical inputs can provide the program to guide self-assembly that yields hydrogels with stable, complex, and spatially varying structure and properties.

  4. Evaluation of spatial plan in controlling stream flow rate in Wakung Watershed, Pemalang, Central Java, Indonesia

    Science.gov (United States)

    Anwar, Y.; Setyasih, I.; Setiawan, M. A.; Christanto, N.

    2018-04-01

    Evaluation study for such a regional spatial plan (RTRW) in Indonesia has not been evaluated for its effectiveness in controlling the surface run off that contributed to streamflow. This necessity can be accomplishsed by applying a modeling approach, such as Soil Water Assessment Tool (SWAT). The objectives of this research are 1) to simulate the streamflow of Wakung watershed based on actual landuse, 2) to predict streamflow of Wakung watershed based on RTRW, and 3) to evaluate the effectiveness of the RTRW of Pemalang District in controling streamflow rate at Wakung Watershed. ArcSWAT model was used to determine the erosion rate prediction. The model was then calibrated by using SWATCUP. Model performance were tested by using R2 and ENS. The calibration and validation results showed that R2 and ENS (monthly) > 0.5. The result of SWAT simulation in Wakung sub-watershed reaching 161 - 4950 m3/s/years for W-A scenario (actual landuse and weather data of 2013), for scenario W-R (RTRW and weather data of 2013), 330 - 4919 m3/s/year. The comparison between actual and spatial plan land use data for stream flow is showing that the W-A scenario is lower than the W-R scenario in 19 sub watersheds. This is because there are many plans for adding land use for urban and intensive horticulture land in areas with steep slopes (> 25%). This condition is caused by the demands of fulfilling the needs of settlement and food for people in the Wakung watershed.

  5. Spatially-Distributed Cost-Effectiveness Analysis Framework to Control Phosphorus from Agricultural Diffuse Pollution.

    Directory of Open Access Journals (Sweden)

    Runzhe Geng

    Full Text Available Best management practices (BMPs for agricultural diffuse pollution control are implemented at the field or small-watershed scale. However, the benefits of BMP implementation on receiving water quality at multiple spatial is an ongoing challenge. In this paper, we introduce an integrated approach that combines risk assessment (i.e., Phosphorus (P index, model simulation techniques (Hydrological Simulation Program-FORTRAN, and a BMP placement tool at various scales to identify the optimal location for implementing multiple BMPs and estimate BMP effectiveness after implementation. A statistically significant decrease in nutrient discharge from watersheds is proposed to evaluate the effectiveness of BMPs, strategically targeted within watersheds. Specifically, we estimate two types of cost-effectiveness curves (total pollution reduction and proportion of watersheds improved for four allocation approaches. Selection of a ''best approach" depends on the relative importance of the two types of effectiveness, which involves a value judgment based on the random/aggregated degree of BMP distribution among and within sub-watersheds. A statistical optimization framework is developed and evaluated in Chaohe River Watershed located in the northern mountain area of Beijing. Results show that BMP implementation significantly (p >0.001 decrease P loss from the watershed. Remedial strategies where BMPs were targeted to areas of high risk of P loss, deceased P loads compared with strategies where BMPs were randomly located across watersheds. Sensitivity analysis indicated that aggregated BMP placement in particular watershed is the most cost-effective scenario to decrease P loss. The optimization approach outlined in this paper is a spatially hierarchical method for targeting nonpoint source controls across a range of scales from field to farm, to watersheds, to regions. Further, model estimates showed targeting at multiple scales is necessary to optimize program

  6. Subtle Distinctions: How Attentional Templates Influence EEG Parameters of Cognitive Control in a Spatial Cuing Paradigm

    Directory of Open Access Journals (Sweden)

    Christine Mertes

    2018-03-01

    Full Text Available Using event-related potentials (ERPs of the electroencephalogram, we investigated how cognitive control is altered by the scope of an attentional template currently activated in visual working memory. Participants performed a spatial cuing task where an irrelevant color singleton cue was presented prior to a target array. Blockwise, the target was either a red circle or a gray square and had to be searched within homogenous (gray circles or heterogeneous non-targets (differently colored circles or various shapes. Thereby we aimed to trigger the adoption of different attentional templates: a broader singleton or a narrower, more specific feature template. ERP markers of attentional selection and inhibitory control showed that the amount of cognitive control was overall enhanced when participants searched on the basis of a feature-specific template: the analysis revealed reduced selection (N2pc, frontal P2 and pronounced inhibition (negative shift of frontal N2 of the irrelevant color cue when participants searched for a feature target. On behavioral level attentional capture was most pronounced in the color condition with no differentiation between the task-induced scopes of the attentional template.

  7. Improving understanding of controls on spatial variability in methane fluxes in Arctic tundra

    Science.gov (United States)

    Davidson, Scott J.; Sloan, Victoria; Phoenix, Gareth; Wagner, Robert; Oechel, Walter; Zona, Donatella

    2015-04-01

    The Arctic is experiencing rapid climate change relative to the rest of the globe, and this increase in temperature has feedback effects across hydrological and thermal regimes, plant community distribution and carbon stocks within tundra soils. Arctic wetlands account for a significant amount of methane emissions from natural ecosystems to the atmosphere and with further permafrost degradation under a warming climate, these emissions are expected to increase. Methane (CH4) is an extremely important component of the global carbon cycle with a global warming potential 28.5 times greater than carbon dioxide over a 100 year time scale (IPCC, 2013). In order to validate carbon cycle models, modelling methane at broader landscape scales is needed. To date direct measurements of methane have been sporadic in time and space which, while capturing some key controls on the spatial heterogeneity, make it difficult to accurately upscale methane emissions to the landscape and regional scales. This study investigates what is controlling the spatial heterogeneity of methane fluxes across Arctic tundra. We combined over 300 portable chamber observations from 13 micro-topographic positions (with multiple vegetation types) across three locations spanning a 300km latitudinal gradient in Northern Alaska from Barrow to Ivotuk with synchronous measurements of environmental (soil temperature, soil moisture, water table, active layer thaw depth, pH) and vegetation (plant community composition, height, sedge tiller counts) variables to evaluate key controls on methane fluxes. To assess the diurnal variation in CH4 fluxes, we also performed automated chamber measurements in one study site (Barrow) location. Multiple statistical approaches (regression tree and multiple linear regression) were used to identify key controlling variables and their interactions. Methane emissions across all sites ranged from -0.08 to 15.3 mg C-CH4 m-2 hr-1. As expected, soil moisture was the main control

  8. Separation of Parkinson's patients in early and mature stages from control subjects using one EOG channel

    DEFF Research Database (Denmark)

    Christensen, Julie A.E.; Frandsen, Rune; Kempfner, Jacob

    2012-01-01

    In this study, polysomnographic left side EOG signals from ten control subjects, ten iRBD patients and ten Parkinson's patients were decomposed in time and frequency using wavelet transformation. A total of 28 features were computed as the means and standard deviations in energy measures from...... different reconstructed detail subbands across all sleep epochs during a whole night of sleep. A subset of features was chosen based on a cross validated Shrunken Centroids Regularized Discriminant Analysis, where the controls were treated as one group and the patients as another. Classification...... reflecting EMG activity. This study demonstrates that both analysis of eye movements during sleep as well as EMG activity measured at the EOG channel hold potential of being biomarkers for Parkinson's disease....

  9. Investigation of humidity control via membrane separation for advanced Extravehicular Mobility Unit (EMU) application

    Science.gov (United States)

    Newbold, D. D.; Ray, R. J.; Pledger, W. A.; Mccray, S. B.; Brown, M. F.

    1989-01-01

    This paper describes the development of a membrane-based process for dehumidifying the Extravehicular Mobility Unit (EMU). The membrane process promises to be smaller, lighter, and more energy efficient than the other technologies for dehumidification. The dehydration membranes were tested for 90 days at conditions expected to be present in the EMU. The results of these tests indicate that membrane-based technology can effectively control humidity in the EMU.

  10. Process control of a gaseous diffusion cascade for isotopic separation of uranium

    International Nuclear Information System (INIS)

    Bilous, Olegh; Doneddu, F.

    1986-01-01

    Various aspects of dynamics and process control of a gaseous diffusion cascade are described. The cascade enriches uranium hexafluoride gas (HEX) in the light isotope of uranium in a countercurrent flow. The linearized equations describing the equipment models are derived. One can then write the mass balances on the high and low pressure sides of a stage and the overall heat balance of a stage. These heat and mass balances are linear difference equations on the stage number with time derivatives which are then replaced by jω factors to examine the effects of cyclic perturbations. The mass balances are first treated for a cascade section of 12 stages with temperatures assumed constant. The effect of a perturbation of pressure on one of the stages is described first for ω=0 (that is for steady state). Then Nyquist diagrams are obtained. The effect of transport change is also studied. Then temperature is introduced, assuming pressures to be constant. The cases of a section of 12 stages and a cascade of 120 stages are examined. Again Nyquist diagrams of temperature frequency response to a perturbation on one stage are calculated. Process control of the heat exchangers is introduced. The method used to solve the difference equations may be applied to other types of perturbations and to the complete scheme of process control. (author)

  11. Antagonistic control of social versus repetitive self-grooming behaviors by separable amygdala neuronal subsets.

    Science.gov (United States)

    Hong, Weizhe; Kim, Dong-Wook; Anderson, David J

    2014-09-11

    Animals display a range of innate social behaviors that play essential roles in survival and reproduction. While the medial amygdala (MeA) has been implicated in prototypic social behaviors such as aggression, the circuit-level mechanisms controlling such behaviors are not well understood. Using cell-type-specific functional manipulations, we find that distinct neuronal populations in the MeA control different social and asocial behaviors. A GABAergic subpopulation promotes aggression and two other social behaviors, while neighboring glutamatergic neurons promote repetitive self-grooming, an asocial behavior. Moreover, this glutamatergic subpopulation inhibits social interactions independently of its effect to promote self-grooming, while the GABAergic subpopulation inhibits self-grooming, even in a nonsocial context. These data suggest that social versus repetitive asocial behaviors are controlled in an antagonistic manner by inhibitory versus excitatory amygdala subpopulations, respectively. These findings provide a framework for understanding circuit-level mechanisms underlying opponency between innate behaviors, with implications for their perturbation in psychiatric disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Voltage-Controlled Quantum Dynamics and Generation Entanglement between Two Separated Quantum-Dot Molecules Embedded in Photonic Crystal Cavities

    International Nuclear Information System (INIS)

    Cheng Mu-Tian; Song Yan-Yan; Ma Xiao-San; Wang Xia

    2014-01-01

    Voltage-controlled quantum dynamics of two quantum-dot molecules (QDMs) embedded in two separated photonic crystal cavities are theoretically investigated. We show numerically that generation of entangled states and population transfer between the two QDMs can be realized with the same coupling parameters. The effects of parameters deviation and dissipations on generation entangled states and populations transfer are also discussed. The results may be used for realization of new-type of solid state quantum devices and integrated electro-optical devices

  13. Happiness increases verbal and spatial working memory capacity where sadness does not: Emotion, working memory and executive control.

    Science.gov (United States)

    Storbeck, Justin; Maswood, Raeya

    2016-08-01

    The effects of emotion on working memory and executive control are often studied in isolation. Positive mood enhances verbal and impairs spatial working memory, whereas negative mood enhances spatial and impairs verbal working memory. Moreover, positive mood enhances executive control, whereas negative mood has little influence. We examined how emotion influences verbal and spatial working memory capacity, which requires executive control to coordinate between holding information in working memory and completing a secondary task. We predicted that positive mood would improve both verbal and spatial working memory capacity because of its influence on executive control. Positive, negative and neutral moods were induced followed by completing a verbal (Experiment 1) or spatial (Experiment 2) working memory operation span task to assess working memory capacity. Positive mood enhanced working memory capacity irrespective of the working memory domain, whereas negative mood had no influence on performance. Thus, positive mood was more successful holding information in working memory while processing task-irrelevant information, suggesting that the influence mood has on executive control supersedes the independent effects mood has on domain-specific working memory.

  14. Optimal Design of Safety Instrumented Systems for Pressure Control of Methanol Separation Columns in the Bisphenol a Manufacturing Process

    Directory of Open Access Journals (Sweden)

    In-Bok Lee

    2016-12-01

    Full Text Available A bisphenol A production plant possesses considerable potential risks in the top of the methanol separation column, as pressurized acetone, methanol, and water are processed at an elevated temperature, especially in the event of an abnormal pressure increase due to a sudden power outage. This study assesses the potential risks in the methanol separation column through hazard and operability assessments and evaluates the damages in the case of fire and explosion accident scenarios. The study chooses three leakage scenarios: a 5-mm puncture on the methanol separation column, a 50-mm diameter fracture of a discharge pipe and a catastrophic rupture, and, simulated using Phast (Ver. 6.531, the concentration distribution of scattered methanol, thermal radiation distribution of fires, and overpressure distribution of vapor cloud explosions. Implementation of a safety-instrumented system equipped with two-out-of-three voting as a safety measure can detect overpressure at the top of the column and shut down the main control valve and the emergency shutoff valve simultaneously. By applying a safety integrity level of three, the maximal release volume of the safety relief valve can be reduced and, therefore, the design capacity of the flare stack can also be reduced. Such integration will lead to improved safety at a reduced cost.

  15. RANS Simulation of the Separated Flow over a Bump with Active Control

    Science.gov (United States)

    Iaccarino, Gianluca; Marongiu, Claudio; Catalano, Pietro; Amato, Marcello

    2003-01-01

    The objective of this paper is to investigate the accuracy of Reynolds-Averaged Navier- Stokes (RANS) techniques in predicting the effect of steady and unsteady flow control devices. This is part of a larger effort in applying numerical simulation tools to investigate of the performance of synthetic jets in high Reynolds number turbulent flows. RANS techniques have been successful in predicting isolated synthetic jets as reported by Kral et al. Nevertheless, due to the complex, and inherently unsteady nature of the interaction between the synthetic jet and the external boundary layer flow, it is not clear whether RANS models can represent the turbulence statistics correctly.

  16. Particle detector spatial resolution

    International Nuclear Information System (INIS)

    Perez-Mendez, V.

    1992-01-01

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs

  17. Entrainment and Control of Bacterial Populations: An in Silico Study over a Spatially Extended Agent Based Model.

    Science.gov (United States)

    Mina, Petros; Tsaneva-Atanasova, Krasimira; Bernardo, Mario di

    2016-07-15

    We extend a spatially explicit agent based model (ABM) developed previously to investigate entrainment and control of the emergent behavior of a population of synchronized oscillating cells in a microfluidic chamber. Unlike most of the work in models of control of cellular systems which focus on temporal changes, we model individual cells with spatial dependencies which may contribute to certain behavioral responses. We use the model to investigate the response of both open loop and closed loop strategies, such as proportional control (P-control), proportional-integral control (PI-control) and proportional-integral-derivative control (PID-control), to heterogeinities and growth in the cell population, variations of the control parameters and spatial effects such as diffusion in the spatially explicit setting of a microfluidic chamber setup. We show that, as expected from the theory of phase locking in dynamical systems, open loop control can only entrain the cell population in a subset of forcing periods, with a wide variety of dynamical behaviors obtained outside these regions of entrainment. Closed-loop control is shown instead to guarantee entrainment in a much wider region of control parameter space although presenting limitations when the population size increases over a certain threshold. In silico tracking experiments are also performed to validate the ability of classical control approaches to achieve other reference behaviors such as a desired constant output or a linearly varying one. All simulations are carried out in BSim, an advanced agent-based simulator of microbial population which is here extended ad hoc to include the effects of control strategies acting onto the population.

  18. Separating Active and Passive Influences on Stomatal Control of Transpiration[OPEN

    Science.gov (United States)

    McAdam, Scott A.M.; Brodribb, Timothy J.

    2014-01-01

    Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior. PMID:24488969

  19. Separation and purification of curcumin preparation of morphology controlled micro particles

    Directory of Open Access Journals (Sweden)

    Ts Tsedendorj

    2014-12-01

    Full Text Available Curcumin was extracted from turmeric plants which is the most commonly used natural pigments, and possess a variety of pharmacological functions except for using pigment. The morphology and particle size of curcumin are main factors affecting the application. Therefore, the morphology and particle size distribution of curcumin were effectively controlled by advanced technology, which is significant for expanding the application and added value of curcumin. The curcumin crystal was obtained from curcumin pigments by using column chromatography and recrystallization techniques. The composition and structure of curcumin were characterized by elementary analysis, UV-Vis, IR and NMR. Micronization of curcumin was carried out the Solution Enhanced Dispersion by Supercritical Fluids (SEDS technology. In the process, supercritical carbon dioxide was used as anti-solvent and acetone/dichloromethane (1:4, v:v was used as solvent. The curcumin crystals with PSs of about 378 μm were successfully micronized by the SEDS process to micro particles with PSs of about 2.6-10 μm. The acicular, leaves, dendritic and tubular micro particles were obtained through controlling parameters such as pressure, temperature, solution concentration and solution flow rate.DOI: http://doi.dx.org/10.5564/mjc.v15i0.314 Mongolian Journal of Chemistry  15 (41, 2014, p11-14

  20. The separation of control variables in an H/sup /minus// ion source

    International Nuclear Information System (INIS)

    Bowling, P.S.; Brown, S.K.

    1988-01-01

    This paper describes a successful methodology which was used to classify a series if waveforms taken from a 100 ma H/sup /minus// ion source at Los Alamos. The series of 260 waveforms was divided into a ''training'' set and a ''test'' set. A sequence of mathematical transformations was performed on the ''training'' waveforms data and then it was subjected to discriminant analysis. The analysis generates a set of filters which will allow classification of an unknown waveform in the ''test'' set as being either stable or unstable; if stable, whether optimal or not; if not optimal, which of the six control parameters should be adjusted to bring it to an optimal condition. We have found that the probability of successful classification using this methodology is 91.5%. 3 refs., 4 figs., 2 tabs

  1. Mapping Drought Sensitivity of Ecosystem Functioning in Mountainous Watersheds: Spatial Heterogeneity and Geological-Geomorphological Control

    Science.gov (United States)

    Wainwright, H. M.; Steefel, C. F.; Williams, K. H.; Hubbard, S. S.; Enquist, B. J.; Steltzer, H.; Sarah, T.

    2016-12-01

    Mountainous watersheds in the Upper Colorado River Basin play a critical role in supplying water and nutrients to western North America. Ecosystem functioning in those regions - including plant dynamics and biogeochemical cycling - is known to be limited by water availability. Under the climate change, early snowmelt and increasing temperature are expected to intensify the drought conditions in early growing seasons. Although the impact of early-season drought has been documented in plot-scale experiments, ascertaining its significance in mountainous watersheds is challenging given the highly heterogeneous nature of the systems with complex terrain and diverse plant functional types (PFTs). The objectives of this study are (1) to map the regions where the plant dynamics are relatively more sensitive to drought conditions based on historical satellite and climate data, and (2) to identify the environmental controls (e.g., geomorphology, elevation, geology, snow and PFT) on drought sensitivity. We characterize the spatial heterogeneity of drought sensitivity in four watersheds (a 15 x 15 km domain) near the Rocky Mountain Biological Laboratory in Colorado, USA. Following previous plot-scale studies, we first define the drought sensitivity based on annual peak NDVI (Landsat 5) and climatic datasets. Non-parametric tree-based machine learning methods are used to identify the significant environmental controls, using high-resolution LiDAR digital elevation map and peak snow-water-equivalent distribution from NASA airborne snow observatory. Results show that the drought sensitivity is negatively correlated with elevation, suggesting increased water limitations in lower elevation (less snow, higher temperature). The drought sensitivity is more spatially variable in shallow-rooted plant types, affected by local hydrological conditions. We also found geomorphological and geological controls, such as high sensitivity in the steep well-drained glacial moraine regions. Our

  2. Spatial patterns and controls of soil chemical weathering rates along a transient hillslope

    Science.gov (United States)

    Yoo, K.; Mudd, S.M.; Sanderman, J.; Amundson, Ronald; Blum, A.

    2009-01-01

    Hillslopes have been intensively studied by both geomorphologists and soil scientists. Whereas geomorphologists have focused on the physical soil production and transport on hillslopes, soil scientists have been concerned with the topographic variation of soil geochemical properties. We combined these differing approaches and quantified soil chemical weathering rates along a grass covered hillslope in Coastal California. The hillslope is comprised of both erosional and depositional sections. In the upper eroding section, soil production is balanced by physical erosion and chemical weathering. The hillslope then transitions to a depositional slope where soil accumulates due to a historical reduction of channel incision at the hillslope's base. Measurements of hillslope morphology and soil thickness were combined with the elemental composition of the soil and saprolite, and interpreted through a process-based model that accounts for both chemical weathering and sediment transport. Chemical weathering of the minerals as they moved downslope via sediment transport imparted spatial variation in the geochemical properties of the soil. Inverse modeling of the field and laboratory data revealed that the long-term soil chemical weathering rates peak at 5 g m- 2 yr- 1 at the downslope end of the eroding section and decrease to 1.5 g m- 2 yr- 1 within the depositional section. In the eroding section, soil chemical weathering rates appear to be primarily controlled by the rate of mineral supply via colluvial input from upslope. In the depositional slope, geochemical equilibrium between soil water and minerals appeared to limit the chemical weathering rate. Soil chemical weathering was responsible for removing 6% of the soil production in the eroding section and 5% of colluvial influx in the depositional slope. These were among the lowest weathering rates reported for actively eroding watersheds, which was attributed to the parent material with low amount of weatherable

  3. Paracetamol sharpens reflection and spatial memory: a double-blind randomized controlled study in healthy volunteers

    Directory of Open Access Journals (Sweden)

    Pickering G

    2016-12-01

    Full Text Available Gisèle Pickering,1–3 Nicolas Macian,1,2 Claude Dubray,1–3 Bruno Pereira4 1University Hospital, CHU Clermont-Ferrand, Centre de Pharmacologie Clinique, 2Inserm, CIC 1405, UMR Neurodol 1107, 3Clermont Université, Laboratoire de Pharmacologie, Faculté de médecine, 4CHU de Clermont-Ferrand, Délégation Recherche Clinique Innovation, Clermont-Ferrand, France Background: Acetaminophen (APAP, paracetamol mechanism for analgesic and antipyretic outcomes has been largely addressed, but APAP action on cognitive function has not been studied in humans. Animal studies have suggested an improved cognitive performance but the link with analgesic and antipyretic modes of action is incomplete. This study aims at exploring cognitive tests in healthy volunteers in the context of antinociception and temperature regulation. A double-blind randomized controlled study (NCT01390467 was carried out from May 30, 2011 to July 12, 2011. Methods: Forty healthy volunteers were included and analyzed. Nociceptive thresholds, core temperature (body temperature, and a battery of cognitive tests were recorded before and after oral APAP (2 g or placebo: Information sampling task for predecisional processing, Stockings of Cambridge for spatial memory, reaction time, delayed matching of sample, and pattern recognition memory tests. Analysis of variance for repeated measures adapted to crossover design was performed and a two-tailed type I error was fixed at 5%. Results: APAP improved information sampling task (diminution of the number of errors, latency to open boxes, and increased number of opened boxes; all P<0.05. Spatial planning and working memory initial thinking time were decreased (P=0.04. All other tests were not modified by APAP. APAP had an antinociceptive effect (P<0.01 and body temperature did not change. Conclusion: This study shows for the first time that APAP sharpens decision making and planning strategy in healthy volunteers and that cognitive performance

  4. Erosion control and protection from torrential floods in Serbia-spatial aspects

    Directory of Open Access Journals (Sweden)

    Ristić Ratko

    2011-01-01

    Full Text Available Torrential floods represent the most frequent phenomenon within the category of “natural risks” in Serbia. The representative examples are the torrential floods on the experimental watersheds of the rivers Manastirica (June 1996 and Kamišna (May 2007. Hystorical maximal discharges (Qmaxh were reconstructed by use of ″hydraulics flood traces″ method. Computations of maximal discharges (Qmaxc, under hydrological conditions after the restoration of the watersheds, were performed by use of a synthetic unit hydrograph theory and Soil Conservation Service methodology. Area sediment yields and intensity of erosion processes were estimated on the basis of the “Erosion Potential Method”. The actual state of erosion processes is represented by the coefficients of erosion Z=0.475 (Manastirica and Z=0.470 (Kamišna. Restoration works have been planned with a view to decreasing yields of erosive material, increasing water infiltration capacity and reducing flood runoff. The planned state of erosion processes is represented by the coefficients of erosion Z=0.343 (Manastirica and Z=0.385 (Kamišna. The effects of hydrological changes were estimated by the comparison of historical maximal discharges and computed maximal discharges (under the conditions after the planned restoration. The realisation of restoration works will help decrease annual yields of erosive material from Wа=24357 m3 to Wа=16198.0 m3 (Manastirica and from Wа=19974 m3 to Wа=14434 m3 (Kamišna. The values of historical maximal discharges (QmaxhMan=154.9 m3•s-1; QmaxhKam=76.3 m3•s-1 were significantly decreased after the restoration (QmaxcMan=84.5 m3 •s-1; QmaxcKam=43.7 m3•s-1, indicating the improvement of hydrological conditions, as a direct consequence of erosion and torrent control works. Integrated management involves biotechnical works on the watershed, technical works on the hydrographic network within a precisely defined administrative and spatial framework in

  5. Human Skin Constructs with Spatially Controlled Vasculature Using Primary and iPSC-Derived Endothelial Cells.

    Science.gov (United States)

    Abaci, Hasan E; Guo, Zongyou; Coffman, Abigail; Gillette, Brian; Lee, Wen-Han; Sia, Samuel K; Christiano, Angela M

    2016-07-01

    Vascularization of engineered human skin constructs is crucial for recapitulation of systemic drug delivery and for their long-term survival, functionality, and viable engraftment. In this study, the latest microfabrication techniques are used and a novel bioengineering approach is established to micropattern spatially controlled and perfusable vascular networks in 3D human skin equivalents using both primary and induced pluripotent stem cell (iPSC)-derived endothelial cells. Using 3D printing technology makes it possible to control the geometry of the micropatterned vascular networks. It is verified that vascularized human skin equivalents (vHSEs) can form a robust epidermis and establish an endothelial barrier function, which allows for the recapitulation of both topical and systemic delivery of drugs. In addition, the therapeutic potential of vHSEs for cutaneous wounds on immunodeficient mice is examined and it is demonstrated that vHSEs can both promote and guide neovascularization during wound healing. Overall, this innovative bioengineering approach can enable in vitro evaluation of topical and systemic drug delivery as well as improve the potential of engineered skin constructs to be used as a potential therapeutic option for the treatment of cutaneous wounds. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Basic research on separation control of long life nuclides in fuel reprocessing processes

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Atsuyuki; Usami, Go [Tokyo Univ. (Japan). Faculty of Engineering; Maeda, Mitsuru; Fujine, Sachio; Uchiyama, Gunzo; Kihara, Takehiro; Asakura, Toshihide; Hotoku, Shinobu

    1996-01-01

    The behavior of technetium (Tc) in nuclear fuel reprocessing processes has become the subject to be elucidated in the transition to distribution process by coextraction and the catalytic action in distribution process. In order to forecast or control the behavior of Tc in reprocessing processes, it is necessary to understand that at which valence Tc exists stably in respective processes. Tc is stable at 7 valence in nitric acid solution expected in reprocessing. In this research, the reaction speed of the oxidation and reduction reactions of rhenium (Re) which simulates Tc was measured by laser Raman spectroscopy which can do high speed analysis of valence. The experimental method is explained. The Raman spectra of Re in the experimental system of this research were measured in perchloric acid solution and nitric acid solution, and compared with the values in literatures. As the result, the validity of this research was assured. It was confirmed that Re(7) was not reduced by sulfamic acid and ascorbic acid. Re(7) was reduced by thiocyanic acid once, but was oxidized again by the reaction of thiocyanic acid and nitric acid. (K.I.)

  7. Yersinia pseudotuberculosis Spatially Controls Activation and Misregulation of Host Cell Rac1.

    Directory of Open Access Journals (Sweden)

    2005-10-01

    Full Text Available Yersinia pseudotuberculosis binds host cells and modulates the mammalian Rac1 guanosine triphosphatase (GTPase at two levels. Activation of Rac1 results from integrin receptor engagement, while misregulation is promoted by translocation of YopE and YopT proteins into target cells. Little is known regarding how these various factors interplay to control Rac1 dynamics. To investigate these competing processes, the localization of Rac1 activation was imaged microscopically using fluorescence resonance energy transfer. In the absence of translocated effectors, bacteria induced activation of the GTPase at the site of bacterial binding. In contrast, the entire cellular pool of Rac1 was inactivated shortly after translocation of YopE RhoGAP. Inactivation required membrane localization of Rac1. The translocated protease YopT had very different effects on Rac1. This protein, which removes the membrane localization site of Rac1, did not inactivate Rac1, but promoted entry of cleaved activated Rac1 molecules into the host cell nucleus, allowing Rac1 to localize with nuclear guanosine nucleotide exchange factors. As was true for YopE, membrane-associated Rac1 was the target for YopT, indicating that the two translocated effectors may compete for the same pool of target protein. Consistent with the observation that YopE inactivation requires membrane localization of Rac1, the presence of YopT in the cell interfered with the action of the YopE RhoGAP. As a result, interaction of target cells with a strain that produces both YopT and YopE resulted in two spatially distinct pools of Rac1: an inactive cytoplasmic pool and an activated nuclear pool. These studies demonstrate that competition between bacterial virulence factors for access to host substrates is controlled by the spatial arrangement of a target protein. In turn, the combined effects of translocated bacterial proteins are to generate pools of a single signaling molecule with distinct localization and

  8. Floral organ abscission peptide IDA and its HAE/HSL2 receptors control cell separation during lateral root emergence.

    Science.gov (United States)

    Kumpf, Robert P; Shi, Chun-Lin; Larrieu, Antoine; Stø, Ida Myhrer; Butenko, Melinka A; Péret, Benjamin; Riiser, Even Sannes; Bennett, Malcolm J; Aalen, Reidunn B

    2013-03-26

    Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LIKE2 (HSL2). Emergence of new lateral root primordia, initiated deep inside the root under the influence of auxin, is similarly dependent on cell wall dissolution between cells in the overlaying endodermal, cortical, and epidermal tissues. Here we show that this process requires IDA, HAE, and HSL2. Mutation in these genes constrains the passage of the growing lateral root primordia through the overlaying layers, resulting in altered shapes of the lateral root primordia and of the overlaying cells. The HAE and HSL2 receptors are redundant in function during floral organ abscission, but during lateral root emergence they are differentially involved in regulating cell wall remodeling genes. In the root, IDA is strongly auxin-inducible and dependent on key regulators of lateral root emergence--the auxin influx carrier LIKE AUX1-3 and AUXIN RESPONSE FACTOR7. The expression levels of the receptor genes are only transiently induced by auxin, suggesting they are limiting factors for cell separation. We conclude that elements of the same cell separation signaling module have been adapted to function in different developmental programs.

  9. Effects of Input Voltage on Flow Separation Control for Low-Pressure Turbine at Low Reynolds Number by Plasma Actuators

    Directory of Open Access Journals (Sweden)

    Takayuki Matsunuma

    2012-01-01

    Full Text Available Active flow control using dielectric barrier discharge (DBD plasma actuators was investigated to reattach the simulated boundary layer separation on the suction surface of a turbine blade at low Reynolds number, Re = 1.7 × 104. The flow separation is induced on a curved plate installed in the test section of a low-speed wind tunnel. Particle image velocimetry (PIV was used to obtain instantaneous and time-averaged two-dimensional velocity measurements. The amplitude of input voltage for the plasma actuator was varied from ±2.0 kV to ±2.8 kV. The separated flow reattached on the curved wall when the input voltage was ±2.4 kV and above. The displacement thickness of the boundary layer near the trailing edge decreased by 20% at ±2.0 kV. The displacement thickness was suddenly reduced as much as 56% at ±2.2 kV, and it was reduced gradually from ±2.4 kV to ±2.8 kV (77% reduction. The total pressure loss coefficient, estimated from the boundary layer displacement thickness and momentum thickness, was 0.172 at the baseline (actuator off condition. The total pressure loss was reduced to 0.107 (38% reduction at ±2.2 kV and 0.078 (55% reduction at ±2.8 kV.

  10. Geographic profiling as a novel spatial tool for targeting infectious disease control

    Directory of Open Access Journals (Sweden)

    Fuller Douglas O

    2011-05-01

    Full Text Available Abstract Background Geographic profiling is a statistical tool originally developed in criminology to prioritise large lists of suspects in cases of serial crime. Here, we use two data sets - one historical and one modern - to show how it can be used to locate the sources of infectious disease. Results First, we re-analyse data from a classic epidemiological study, the 1854 London cholera outbreak. Using 321 disease sites as input, we evaluate the locations of 13 neighbourhood water pumps. The Broad Street pump - the outbreak's source- ranks first, situated in the top 0.2% of the geoprofile. We extend our study with an analysis of reported malaria cases in Cairo, Egypt, using 139 disease case locations to rank 59 mosquitogenic local water sources, seven of which tested positive for the vector Anopheles sergentii. Geographic profiling ranks six of these seven sites in positions 1-6, all in the top 2% of the geoprofile. In both analyses the method outperformed other measures of spatial central tendency. Conclusions We suggest that geographic profiling could form a useful component of integrated control strategies relating to a wide variety of infectious diseases, since evidence-based targeting of interventions is more efficient, environmentally friendly and cost-effective than untargeted intervention.

  11. Spatial Multiplexing of Atom-Photon Entanglement Sources using Feedforward Control and Switching Networks.

    Science.gov (United States)

    Tian, Long; Xu, Zhongxiao; Chen, Lirong; Ge, Wei; Yuan, Haoxiang; Wen, Yafei; Wang, Shengzhi; Li, Shujing; Wang, Hai

    2017-09-29

    The light-matter quantum interface that can create quantum correlations or entanglement between a photon and one atomic collective excitation is a fundamental building block for a quantum repeater. The intrinsic limit is that the probability of preparing such nonclassical atom-photon correlations has to be kept low in order to suppress multiexcitation. To enhance this probability without introducing multiexcitation errors, a promising scheme is to apply multimode memories to the interface. Significant progress has been made in temporal, spectral, and spatial multiplexing memories, but the enhanced probability for generating the entangled atom-photon pair has not been experimentally realized. Here, by using six spin-wave-photon entanglement sources, a switching network, and feedforward control, we build a multiplexed light-matter interface and then demonstrate a ∼sixfold (∼fourfold) probability increase in generating entangled atom-photon (photon-photon) pairs. The measured compositive Bell parameter for the multiplexed interface is 2.49±0.03 combined with a memory lifetime of up to ∼51  μs.

  12. Spatial mismatch between sea lamprey behaviour and trap location explains low success at trapping for control

    Science.gov (United States)

    Rous, Andrew M.; McLean, Adrienne R.; Barber, Jessica; Bravener, Gale; Castro-Santos, Theodore; Holbrook, Christopher M.; Imre, Istvan; Pratt, Thomas C.; McLaughlin, Robert L.

    2017-01-01

    Crucial to the management of invasive species is understanding space use and the environmental features affecting space use. Improved understanding of space use by invasive sea lamprey (Petromyzon marinus) could help researchers discern why trap success in large rivers is lower than needed for effective control. We tested whether manipulating discharge nightly could increase trap success at a hydroelectric generating station on the St. Marys River. We quantified numbers of acoustically tagged sea lampreys migrating up to, and their space use at, the hydroelectric generating station. In 2011 and 2012, 78% and 68%, respectively, of tagged sea lampreys reached the generating station. Sea lampreys were active along the face, but more likely to occur at the bottom and away from the traps near the surface, especially when discharge was high. Our findings suggest that a low probability of encountering traps was due to spatial (vertical) mismatch between space use by sea lamprey and trap locations and that increasing discharge did not alter space use in ways that increased trap encounter. Understanding space use by invasive species can help managers assess the efficacy of trapping and ways of improving trapping success.

  13. Spatially controlled immobilisation of biomolecules: A complete approach in green chemistry

    Science.gov (United States)

    Grinenval, Eva; Nonglaton, Guillaume; Vinet, Françoise

    2014-01-01

    The development of 'green' sensors is a challenging task in the field of biomolecule sensing, for example in the detection of cardiac troponin-I (cTnI). In the present work a complete approach in green chemistry was developed to create chemically active patterns for the immobilisation of biological probes. This key technology is discussed on the basis of the twelve green chemistry principles, and is a combination of surface patterning by spotting and surface chemistries modified by molecular vapour deposition. The (1H,1H,2H,2H)-perfluorodecyltrichlorosilane (FDTS) was used as a novel anti-adsorption layer while the 3,4-epoxybutyltrimethoxysilane (EBTMOS) was used to immobilise probes. Oligonucleotides and the anti-cTnI antibody were studied. The spatially controlled immobilisation of probes was characterised by fluorescence. The demonstrated surface modification has broad applications in areas such as diagnostics and bio-chemical sensing. Moreover, the environmental impacts of surface patterning and surface chemistry were discussed from a 'greenness' point of view.

  14. Spatial Computation

    Science.gov (United States)

    2003-12-01

    Computation and today’s microprocessors with the approach to operating system architecture, and the controversy between microkernels and monolithic kernels...Both Spatial Computation and microkernels break away a relatively monolithic architecture into in- dividual lightweight pieces, well specialized...for their particular functionality. Spatial Computation removes global signals and control, in the same way microkernels remove the global address

  15. Controlling Microstructure-Transport Interplay in Highly Phase-Separated Perfluorosulfonated Aromatic Multiblock Ionomers via Molecular Architecture Design.

    Science.gov (United States)

    Nguyen, Huu-Dat; Assumma, Luca; Judeinstein, Patrick; Mercier, Regis; Porcar, Lionel; Jestin, Jacques; Iojoiu, Cristina; Lyonnard, Sandrine

    2017-01-18

    Proton-conducting multiblock polysulfones bearing perfluorosulfonic acid side chains were designed to encode nanoscale phase-separation, well-defined hydrophilic/hydrophobic interfaces, and optimized transport properties. Herein, we show that the superacid side chains yield highly ordered morphologies that can be tailored by best compromising ion-exchange capacity and block lengths. The obtained microstructures were extensively characterized by small-angle neutron scattering (SANS) over an extended range of hydration. Peculiar swelling behaviors were evidenced at two different scales and attributed to the dilution of locally flat polymer particles. We evidence the direct correlation between the quality of interfaces, the topology and connectivity of ionic nanodomains, the block superstructure long-range organization, and the transport properties. In particular, we found that the proton conductivity linearly depends on the microscopic expansion of both ionic and block domains. These findings indicate that neat nanoscale phase-separation and block-induced long-range connectivity can be optimized by designing aromatic ionomers with controlled architectures to improve the performances of polymer electrolyte membranes.

  16. The potential of hybrid micro-vortex generators to control flow separation of NACA 4415 airfoil in subsonic flow

    Science.gov (United States)

    Jumahadi, Muhammad Taufiq; Saad, Mohd Rashdan; Idris, Azam Che; Sujipto, Suriyadi; Rahman, Mohd Rosdzimin Abdul

    2018-02-01

    Boundary layer separation is detrimental to the lift and drag of most aeronautical applications. Many vortex generators (VG), both passive and active have been designed to reduce these drawbacks. This study targets to investigate the effectiveness of hybrid micro-VGs, which combine both active and passive micro-VGs in controlling separation under subsonic conditions. NACA 4415 airfoils installed with passive, active and hybrid micro-VGs each are designed, 3D printed, and tested in a wind tunnel at 26.19 m/s under Re = 2.5x105. The lift and drag measurements from a 3-component force balance prove that hybrid micro-VGs increase lift by up to 21.2%, increase drag by more than 11.3% and improve lift-to-drag ratio by at least 8.6% until up to 33.7%. From this research, it is believed that hybrid micro-VGs are competitive to the performance of active VGs and a better configuration is to be considered to reduce parasitic drag and outstand active VGs.

  17. Roles for the subiculum in spatial information processing, memory, motivation and the temporal control of behaviour.

    Science.gov (United States)

    O'Mara, Shane M; Sanchez-Vives, Maria V; Brotons-Mas, Jorge R; O'Hare, Eugene

    2009-08-01

    The subiculum is in a pivotal position governing the output of the hippocampal formation. Despite this, it is a rather under-explored and sometimes ignored structure. Here, we discuss recent data indicating that the subiculum participates in a wide range of neurocognitive functions and processes. Some of the functions of subiculum are relatively well-known-these include providing a relatively coarse representation of space and participating in, and supporting certain aspects of, memory (particularly in the dynamic bridging of temporal intervals). The subiculum also participates in a wide variety of other neurocognitive functions too, however. Much less well-known are roles for the subiculum, and particularly the ventral subiculum, in the response to fear, stress and anxiety, and in the generation of motivated behaviour (particularly the behaviour that underlies drug addiction and the response to reward). There is an emerging suggestion that the subiculum participates in the temporal control of behaviour. It is notable that these latter findings have emerged from a consideration of instrumental behaviour using operant techniques; it may well be the case that the use of the watermaze or similar spatial tasks to assess subicular function (on the presumption that its functions are very similar to the hippocampus proper) has obscured rather than revealed neurocognitive functions of subiculum. The anatomy of subiculum suggests it participates in a rather subtle fashion in a very broad range of functions, rather than in a relatively more isolated fashion in a narrower range of functions, as might be the case for "earlier" components of hippocampal circuitry, such as the CA1 and CA3 subfields. Overall, there appears to a strong dorso-ventral segregation of function within subiculum, with the dorsal subiculum relatively more concerned with space and memory, and the ventral hippocampus concerned with stress, anxiety and reward. Finally, it may be the case that the whole

  18. Influences of Different Land Use Spatial Control Schemes on Farmland Conversion and Urban Development

    Science.gov (United States)

    Zhou, Min; Tan, Shukui; Zhang, Lu

    2015-01-01

    Land use planning is always officially implemented as an effective tool to control urban development and protect farmland. However, its impact on land use change remains untested in China. Using a case study of Hang-Jia-Hu region, the main objective of this paper was to investigate the influence of different land use spatial control schemes on farmland conversion and urban development. Comparisons of farmland conversion and urban development patterns between the urban planning area and the non-urban planning area were characterized by using remote sensing, geographical information systems, and landscape metrics. Results indicated that farmland conversion in the non-urban planning area was more intensive than that in the urban planning area, and that farmland patterns was more fragmented in the non-urban planning area. Built-up land patterns in the non-urban planning area showed a trend of aggregation, while those in the urban planning area had a dual trend of fragmentation and aggregation. Existing built-up areas had less influence on built-up land sprawl in the non-urban planning area than that in the urban planning area. Built-up land sprawl in the form of continuous development in the urban planning area led to farmland conversion; and in the non-urban planning area, built-up land sprawl in the form of leapfrogging development resulted in farmland areal declines and fragmentation. We argued that it is a basic requirement to integrate land use plans in urban and non-urban planning areas for land use planning and management. PMID:25915897

  19. Influences of different land use spatial control schemes on farmland conversion and urban development.

    Science.gov (United States)

    Zhou, Min; Tan, Shukui; Zhang, Lu

    2015-01-01

    Land use planning is always officially implemented as an effective tool to control urban development and protect farmland. However, its impact on land use change remains untested in China. Using a case study of Hang-Jia-Hu region, the main objective of this paper was to investigate the influence of different land use spatial control schemes on farmland conversion and urban development. Comparisons of farmland conversion and urban development patterns between the urban planning area and the non-urban planning area were characterized by using remote sensing, geographical information systems, and landscape metrics. Results indicated that farmland conversion in the non-urban planning area was more intensive than that in the urban planning area, and that farmland patterns was more fragmented in the non-urban planning area. Built-up land patterns in the non-urban planning area showed a trend of aggregation, while those in the urban planning area had a dual trend of fragmentation and aggregation. Existing built-up areas had less influence on built-up land sprawl in the non-urban planning area than that in the urban planning area. Built-up land sprawl in the form of continuous development in the urban planning area led to farmland conversion; and in the non-urban planning area, built-up land sprawl in the form of leapfrogging development resulted in farmland areal declines and fragmentation. We argued that it is a basic requirement to integrate land use plans in urban and non-urban planning areas for land use planning and management.

  20. Spatially Explicit Simulation of Mesotopographic Controls on Peatland Hydrology and Carbon Fluxes

    Science.gov (United States)

    Sonnentag, O.; Chen, J. M.; Roulet, N. T.

    2006-12-01

    A number of field carbon flux measurements, paleoecological records, and model simulations have acknowledged the importance of northern peatlands in terrestrial carbon cycling and methane emissions. An important parameter in peatlands that influences both net primary productivity, the net gain of carbon through photosynthesis, and decomposition under aerobic and anaerobic conditions, is the position of the water table. Biological and physical processes involved in peatland carbon dynamics and their hydrological controls operate at different spatial scales. The highly variable hydraulic characteristics of the peat profile and the overall shape of the peat body as defined by its surface topography at the mesoscale (104 m2) are of major importance for peatland water table dynamics. Common types of peatlands include bogs with a slightly domed centre. As a result of the convex profile, their water supply is restricted to atmospheric inputs, and water is mainly shed by shallow subsurface flow. From a modelling perspective the influence of mesotopographic controls on peatland hydrology and thus carbon balance requires that process-oriented models that examine the links between peatland hydrology, ecosystem functioning, and climate must incorporate some form of lateral subsurface flow consideration. Most hydrological and ecological modelling studies in complex terrain explicitly account for the topographic controls on lateral subsurface flow through digital elevation models. However, modelling studies in peatlands often employ simple empirical parameterizations of lateral subsurface flow, neglecting the influence of peatlands low relief mesoscale topography. Our objective is to explicitly simulate the mesotopographic controls on peatland hydrology and carbon fluxes using the Boreal Ecosystem Productivity Simulator (BEPS) adapted to northern peatlands. BEPS is a process-oriented ecosystem model in a remote sensing framework that takes into account peatlands multi

  1. Hemispheric differences in the voluntary control of spatial attention: direct evidence for a right-hemispheric dominance within frontal cortex.

    Science.gov (United States)

    Duecker, Felix; Formisano, Elia; Sack, Alexander T

    2013-08-01

    Lesion studies in neglect patients have inspired two competing models of spatial attention control, namely, Heilman's "hemispatial" theory and Kinsbourne's "opponent processor" model. Both assume a functional asymmetry between the two hemispheres but propose very different mechanisms. Neuroimaging studies have identified a bilateral dorsal frontoparietal network underlying voluntary shifts of spatial attention. However, lateralization of attentional processes within this network has not been consistently reported. In the current study, we aimed to provide direct evidence concerning the functional asymmetry of the right and left FEF during voluntary shifts of spatial attention. To this end, we applied fMRI-guided neuronavigation to disrupt individual FEF activation foci with a longer-lasting inhibitory patterned TMS protocol followed by a spatial cueing task. Our results indicate that right FEF stimulation impaired the ability of shifting spatial attention toward both hemifields, whereas the effects of left FEF stimulation were limited to the contralateral hemifield. These results provide strong direct evidence for right-hemispheric dominance in spatial attention within frontal cortex supporting Heilman's "hemispatial" theory. This complements previous TMS studies that generally conform to Kinsbourne's "opponent processor" model after disruption of parietal cortex, and we therefore propose that both theories are not mutually exclusive.

  2. Phase-separation control of KxFe2-ySe2 superconductor through rapid-quenching process

    International Nuclear Information System (INIS)

    Yanagisawa, Yusuke; Tanaka, Masashi; Yamashita, Aichi; Suzuki, Kouji; Hara, Hiroshi; Takeya, Hiroyuki; Takano, Yoshihiko; ElMassalami, Mohammed

    2017-01-01

    K x Fe 2-y Se 2 exhibits iron-vacancy ordering at T s ∼ 270°C and separates into two phases: a minor superconducting (iron-vacancy-disordered) phase and a major non-superconducting (iron-vacancy-ordered) phase. The microstructural and superconducting properties of this intermixture can be tuned by an appropriate control of the quenching process through T s . A faster quenching rate leads to a finer microstructure and a suppression of formation of the non-superconducting phase by up to 50%. Nevertheless, such a faster cooling rate induces a monotonic reduction in the superconducting transition temperature (from 30.7 to 26.0 K) and, simultaneously, a decrease in the iron content within the superconducting phase such that the compositional ratio changed from K 0.35 Fe 1.83 Se 2 to K 0.58 Fe 1.71 Se 2 . (author)

  3. Topographic, meteorologic, and canopy controls on the scaling characteristics of the spatial distribution of snow depth fields

    Science.gov (United States)

    Ernesto Trujillo; Jorge A. Ramirez; Kelly J. Elder

    2007-01-01

    In this study, LIDAR snow depths, bare ground elevations (topography), and elevations filtered to the top of vegetation (topography + vegetation) in five 1-km2 areas are used to determine whether the spatial distribution of snow depth exhibits scale invariance, and the control that vegetation, topography, and winds exert on such behavior. The one-dimensional and mean...

  4. Multi-scale spatial controls of understory vegetation in Douglas-fir–western hemlock forests of western Oregon, USA

    Science.gov (United States)

    Julia I. Burton; Lisa M. Ganio; Klaus J. Puettmann

    2014-01-01

    Forest understory vegetation is influenced by broad-scale variation in climate, intermediate scale variation in topography, disturbance and neighborhood interactions. However, little is known about how these multi-scale controls interact to influence observed spatial patterns. We examined relationships between the aggregated cover of understory plant species (%...

  5. Seed-mediated synthesis of silver nanocrystals with controlled sizes and shapes in droplet microreactors separated by air.

    Science.gov (United States)

    Zhang, Lei; Wang, Yi; Tong, Limin; Xia, Younan

    2013-12-17

    Silver nanocrystals with uniform sizes were synthesized in droplet microreactors through seed-mediated growth. The key to the success of this synthesis is the use of air as a carrier phase to generate the droplets. The air not only separates the reaction solution into droplets but also provides O2 for the generation of reducing agent (glycolaldehyde). It also serves as a buffer space for the diffusion of NO, which is formed in situ due to the oxidative etching of Ag nanocrystals with twin defects. For the first time, we were able to generate Ag nanocrystals with controlled sizes and shapes in continuous production by using droplet microreactors. For Ag nanocubes, their edge lengths could be readily controlled in the range of 30-100 nm by varying the reaction time, the amount of seeds, and the concentration of AgNO3 in the droplets. Furthermore, we demonstrated the synthesis of Ag octahedra in the droplet microreactors. We believe that the air-driven droplet generation device can be extended to other noble metals for the production of nanocrystals with controlled sizes and shapes.

  6. Spatial separation of the cyanogenic β-glucosidase ZfBGD2 and cyanogenic glucosides in the haemolymph of Zygaena larvae facilitates cyanide release

    DEFF Research Database (Denmark)

    Pentzold, Stefan; Jensen, Mikael Kryger; Matthes, Annemarie

    2017-01-01

    . Cyanogenic plants contain cyanogenic glucosides and release hydrogen cyanide due to such a well-characterized two-component system. Some arthropods are also cyanogenic, but comparatively little is known about their system. Here, we identify a specific β-glucosidase (ZfBGD2) involved in cyanogenesis from...... larvae of Zygaena filipendulae (Lepidoptera, Zygaenidae), and analyse the spatial organization of cyanide release in this specialized insect. High levels of ZfBGD2 mRNA and protein were found in haemocytes by transcriptomic and proteomic profiling. Heterologous expression in insect cells showed that Zf......BGD2 hydrolyses linamarin and lotaustralin, the two cyanogenic glucosides present in Z. filipendulae. Linamarin and lotaustralin as well as cyanide release were found exclusively in the haemoplasma. Phylogenetic analyses revealed that ZfBGD2 clusters with other insect β...

  7. Regulating outdoor advertisement boards; employing spatial decision support system to control urban visual pollution

    Science.gov (United States)

    Wakil, K.; Hussnain, MQ; Tahir, A.; Naeem, M. A.

    2016-06-01

    Unmanaged placement, size, location, structure and contents of outdoor advertisement boards have resulted in severe urban visual pollution and deterioration of the socio-physical living environment in urban centres of Pakistan. As per the regulatory instruments, the approval decision for a new advertisement installation is supposed to be based on the locational density of existing boards and their proximity or remoteness to certain land- uses. In cities, where regulatory tools for the control of advertisement boards exist, responsible authorities are handicapped in effective implementation due to the absence of geospatial analysis capacity. This study presents the development of a spatial decision support system (SDSS) for regularization of advertisement boards in terms of their location and placement. The knowledge module of the proposed SDSS is based on provisions and restrictions prescribed in regulatory documents. While the user interface allows visualization and scenario evaluation to understand if the new board will affect existing linear density on a particular road and if it violates any buffer restrictions around a particular land use. Technically the structure of the proposed SDSS is a web-based solution which includes open geospatial tools such as OpenGeo Suite, GeoExt, PostgreSQL, and PHP. It uses three key data sets including road network, locations of existing billboards and building parcels with land use information to perform the analysis. Locational suitability has been calculated using pairwise comparison through analytical hierarchy process (AHP) and weighted linear combination (WLC). Our results indicate that open geospatial tools can be helpful in developing an SDSS which can assist solving space related iterative decision challenges on outdoor advertisements. Employing such a system will result in effective implementation of regulations resulting in visual harmony and aesthetic improvement in urban communities.

  8. Paracetamol sharpens reflection and spatial memory: a double-blind randomized controlled study in healthy volunteers.

    Science.gov (United States)

    Pickering, Gisèle; Macian, Nicolas; Dubray, Claude; Pereira, Bruno

    2016-01-01

    Acetaminophen (APAP, paracetamol) mechanism for analgesic and antipyretic outcomes has been largely addressed, but APAP action on cognitive function has not been studied in humans. Animal studies have suggested an improved cognitive performance but the link with analgesic and antipyretic modes of action is incomplete. This study aims at exploring cognitive tests in healthy volunteers in the context of antinociception and temperature regulation. A double-blind randomized controlled study (NCT01390467) was carried out from May 30, 2011 to July 12, 2011. Forty healthy volunteers were included and analyzed. Nociceptive thresholds, core temperature (body temperature), and a battery of cognitive tests were recorded before and after oral APAP (2 g) or placebo: Information sampling task for predecisional processing, Stockings of Cambridge for spatial memory, reaction time, delayed matching of sample, and pattern recognition memory tests. Analysis of variance for repeated measures adapted to crossover design was performed and a two-tailed type I error was fixed at 5%. APAP improved information sampling task (diminution of the number of errors, latency to open boxes, and increased number of opened boxes; all P memory initial thinking time were decreased ( P =0.04). All other tests were not modified by APAP. APAP had an antinociceptive effect ( P body temperature did not change. This study shows for the first time that APAP sharpens decision making and planning strategy in healthy volunteers and that cognitive performance and antinociception are independent of APAP effect on thermogenesis. We suggest that cognitive performance mirrors the analgesic rather than thermic cascade of events, with possibly a central role for serotonergic and cannabinoid systems that need to be explored further in the context of pain and cognition.

  9. Interbasin water transfer, riverine connectivity, and spatial controls on fish biodiversity

    Science.gov (United States)

    Grant, Evan H. Campbell; Lynch, Heather J.; Muneepeerakul, Rachata; Muthukumarasamy, Arunachalam; Rodríguez-Iturbe, Ignacio; Fagan, William F.

    2012-01-01

    Background Large-scale inter-basin water transfer (IBWT) projects are commonly proposed as solutions to water distribution and supply problems. These problems are likely to intensify under future population growth and climate change scenarios. Scarce data on the distribution of freshwater fishes frequently limits the ability to assess the potential implications of an IBWT project on freshwater fish communities. Because connectivity in habitat networks is expected to be critical to species' biogeography, consideration of changes in the relative isolation of riverine networks may provide a strategy for controlling impacts of IBWTs on freshwater fish communities Methods/Principal Findings Using empirical data on the current patterns of freshwater fish biodiversity for rivers of peninsular India, we show here how the spatial changes alone under an archetypal IBWT project will (1) reduce freshwater fish biodiversity system-wide, (2) alter patterns of local species richness, (3) expand distributions of widespread species throughout peninsular rivers, and (4) decrease community richness by increasing inter-basin similarity (a mechanism for the observed decrease in biodiversity). Given the complexity of the IBWT, many paths to partial or full completion of the project are possible. We evaluate two strategies for step-wise implementation of the 11 canals, based on economic or ecological considerations. We find that for each step in the project, the impacts on freshwater fish communities are sensitive to which canal is added to the network. Conclusions/Significance Importantly, ecological impacts can be reduced by associating the sequence in which canals are added to characteristics of the links, except for the case when all 11 canals are implemented simultaneously (at which point the sequence of canal addition is inconsequential). By identifying the fundamental relationship between the geometry of riverine networks and freshwater fish biodiversity, our results will aid in

  10. Human and spatial dimensions of retail density: Revisiting the role of perceived control

    NARCIS (Netherlands)

    van Rompay, Thomas Johannes Lucas; Galetzka, Mirjam; Pruyn, Adriaan T.H.; Moreno Garcia, Jaime

    2008-01-01

    Previous research in environmental psychology and consumer behavior has demonstrated mostly negative effects of human density on consumer experience in retail settings. The effects of spatial density, however, have received scant attention. Results from previous studies show that retail density

  11. A stretchable polymer-carbon nanotube composite electrode for flexible lithium-ion batteries: porosity engineering by controlled phase separation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hojun; Yoo, Jung-Keun; Jung, Yeon Sik [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of); Park, Jong-Hyun [Material R and D Department, LG Display Co., Ltd., Paju-si, Gyeonggi-do (Korea, Republic of); Kim, Jin Ho [Icheon Branch, Korea Institute of Ceramic Engineering and Technology, Icheon-si, Gyeonggi-do (Korea, Republic of); Kang, Kisuk [Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

    2012-08-15

    Flexible energy-storage devices have attracted growing attention with the fast development of bendable electronic systems. However, it still remains a challenge to find reliable electrode materials with both high mechanical flexibility/toughness and excellent electron and lithium-ion conductivity. This paper reports the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible lithium-ion batteries. The systematic optimization of the porous morphology is performed by controllably inducing the phase separation of polymethylmethacrylate (PMMA) in polydimethylsiloxane (PDMS) and removing PMMA, in order to generate well-controlled pore networks. It is demonstrated that the porous CNT-embedded PDMS nanocomposites are capable of good electrochemical performance with mechanical flexibility, suggesting these nanocomposites could be outstanding anode candidates for use in flexible lithium-ion batteries. The optimization of the pore size and the volume fraction provides higher capacity by nearly seven-fold compared to a nonporous nanocomposite. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. The role of ultrasound in controlling the liquid-liquid phase separation and nucleation of vanillin polymorphs I and II

    Science.gov (United States)

    Parimaladevi, P.; Supriya, S.; Srinivasan, K.

    2018-02-01

    The influence of ultrasound on liquid-liquid phase separation (LLPS) and polymorphism of vanillin in aqueous solution has been investigated for the first time by varying the ultrasonic parameters such as power, pulse rate and insonation time at ambient condition. Results reveal that the application of ultrasound controls the impact of LLPS and accelerates the nucleation of vanillin within a short period at lower levels of ultrasonic process parameters, and also enhances the quality of the nucleated crystals. Moreover, the application of ultrasound induces the nucleation of rare and metastable polymorph of vanillin Form II in aqueous solution. But, at higher levels of power, pulse rate and insonation time, the rate of LLPS is found increased and the quality of the crystals becomes deteriorated. Morphology of the nucleated polymorphs were identified through optical microscopy and confirmed by optical goniometry. The internal structure and thermal stability of the grown stable Form I and metastable Form II of vanillin were confirmed through powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) analyses. Further, results suggest that the ultrasound has profound effect in controlling the LLPS and nucleation of vanillin polymorphs in aqueous solution.

  13. Abiotic and biotic controls on local spatial distribution and performance of Boechera stricta

    Directory of Open Access Journals (Sweden)

    KUSUM J NAITHANI

    2014-07-01

    Full Text Available This study investigates the relative influence of biotic and abiotic factors on community dynamics using an integrated approach and highlights the influence of space on genotypic and phenotypic traits in plant community structure. We examined the relative influence of topography, environment, spatial distance, and intra- and interspecific interactions on spatial distribution and performance of Boechera stricta (rockcress, a close perennial relative of model plant Arabidopsis. First, using Bayesian kriging, we mapped the topography and environmental gradients and explored the spatial distribution of naturally occurring rockcress plants and two neighbors, Taraxacum officinale (dandelion and Solidago missouriensis (goldenrod found in close proximity within a typical diverse meadow community across topographic and environmental gradients. We then evaluated direct and indirect relationships among variables using Mantel path analysis and developed a network displaying abiotic and biotic interactions in this community. We found significant spatial autocorrelation among rockcress individuals, either because of common microhabitats as displayed by high density of individuals at lower elevation and high soil moisture area, or limited dispersal as shown by significant spatial autocorrelation of naturally occurring inbred lines, or a combination of both. Goldenrod and dandelion density around rockcress does not show any direct relationship with rockcress fecundity, possibly due to spatial segregation of resources. However, dandelion density around rockcress shows an indirect negative influence on rockcress fecundity via herbivory, indicating interspecific competition. Overall, we suggest that common microhabitat preference and limited dispersal are the main drivers for spatial distribution. However, intra-specific interactions and insect herbivory are the main drivers of rockcress performance in the meadow community.

  14. Effect of the Hartmann number on phase separation controlled by magnetic field for binary mixture system with large component ratio

    Science.gov (United States)

    Heping, Wang; Xiaoguang, Li; Duyang, Zang; Rui, Hu; Xingguo, Geng

    2017-11-01

    This paper presents an exploration for phase separation in a magnetic field using a coupled lattice Boltzmann method (LBM) with magnetohydrodynamics (MHD). The left vertical wall was kept at a constant magnetic field. Simulations were conducted by the strong magnetic field to enhance phase separation and increase the size of separated phases. The focus was on the effect of magnetic intensity by defining the Hartmann number (Ha) on the phase separation properties. The numerical investigation was carried out for different governing parameters, namely Ha and the component ratio of the mixed liquid. The effective morphological evolutions of phase separation in different magnetic fields were demonstrated. The patterns showed that the slant elliptical phases were created by increasing Ha, due to the formation and increase of magnetic torque and force. The dataset was rearranged for growth kinetics of magnetic phase separation in a plot by spherically averaged structure factor and the ratio of separated phases and total system. The results indicate that the increase in Ha can increase the average size of separated phases and accelerate the spinodal decomposition and domain growth stages. Specially for the larger component ratio of mixed phases, the separation degree was also significantly improved by increasing magnetic intensity. These numerical results provide guidance for setting the optimum condition for the phase separation induced by magnetic field.

  15. Synthesis of dynamic phase profile by the correlation technique for spatial control of optical beams in multiplexing and switching

    Science.gov (United States)

    Bugaychuk, Svitlana A.; Gnatovskyy, Vladimir O.; Sidorenko, Andrey V.; Pryadko, Igor I.; Negriyko, Anatoliy M.

    2015-11-01

    New approach for the correlation technique, which is based on multiple periodic structures to create a controllable angular spectrum, is proposed and investigated both theoretically and experimentally. The transformation of an initial laser beam occurs due to the actions of consecutive phase periodic structures, which may differ by their parameters. Then, after the Fourier transformation of a complex diffraction field, the output diffraction orders will be changed both by their intensities and by their spatial position. The controllable change of output angular spectrum is carried out by a simple control of the parameters of the periodic structures. We investigate several simple examples of such management.

  16. A knowledge-based system for control of xenon-induced spatial power oscillations during load-follow operations

    International Nuclear Information System (INIS)

    Chung, Sun-Kyo; Danofsky, R.A.; Spinrad, B.I.

    1988-01-01

    As is well known, large pressurized water reactors (PWRs) are subject to xenon-induced axial power oscillations at some time during a given cycle. Attention to this behavior is required during load-follow operations. A knowledge-based system for controlling xenon-induced spatial power oscillations is described. Experience with a limited set of load-follow patterns has demonstrated that the system is capable of providing advice on appropriate control actions. A simulation model, coupled with a rule-learning process, has been found to be a useful way for determining appropriate weights for the rules that relate power patterns and control actions

  17. The role and origin of dilatant structural environments in the spatial control of geo-economic deposits

    International Nuclear Information System (INIS)

    Rosello, E.

    2010-01-01

    A major controlling the geometry, size and spatial location of the mineralization is the tectonic structure. This control is indeed essential in epigenetic deposits, where the structure is the main factor to determine the circulation, precipitation, and in many cases the generation of hydrothermal solutions associated with mineral deposits and / or alterations. Therefore, learning the type of structural control that a particular deposit is charged on a particular aspect and of fundamental importance not only in yacimientología to contribute to the genetic knowledge but also in economic terms to provide ideas and guidance in tasks prospecting, exploration and mineral exploitation

  18. Controls on the spatial variability of key soil properties: comparing field data with a mechanistic soilscape evolution model

    Science.gov (United States)

    Vanwalleghem, T.; Román, A.; Giraldez, J. V.

    2016-12-01

    There is a need for better understanding the processes influencing soil formation and the resulting distribution of soil properties. Soil properties can exhibit strong spatial variation, even at the small catchment scale. Especially soil carbon pools in semi-arid, mountainous areas are highly uncertain because bulk density and stoniness are very heterogeneous and rarely measured explicitly. In this study, we explore the spatial variability in key soil properties (soil carbon stocks, stoniness, bulk density and soil depth) as a function of processes shaping the critical zone (weathering, erosion, soil water fluxes and vegetation patterns). We also compare the potential of a geostatistical versus a mechanistic soil formation model (MILESD) for predicting these key soil properties. Soil core samples were collected from 67 locations at 6 depths. Total soil organic carbon stocks were 4.38 kg m-2. Solar radiation proved to be the key variable controlling soil carbon distribution. Stone content was mostly controlled by slope, indicating the importance of erosion. Spatial distribution of bulk density was found to be highly random. Finally, total carbon stocks were predicted using a random forest model whose main covariates were solar radiation and NDVI. The model predicts carbon stocks that are double as high on north versus south-facing slopes. However, validation showed that these covariates only explained 25% of the variation in the dataset. Apparently, present-day landscape and vegetation properties are not sufficient to fully explain variability in the soil carbon stocks in this complex terrain under natural vegetation. This is attributed to a high spatial variability in bulk density and stoniness, key variables controlling carbon stocks. Similar results were obtained with the mechanistic soil formation model MILESD, suggesting that more complex models might be needed to further explore this high spatial variability.

  19. Psychological distress following marital separation interacts with a polymorphism in the serotonin transporter gene to predict cardiac vagal control in the laboratory.

    Science.gov (United States)

    Hasselmo, Karen; Sbarra, David A; O'Connor, Mary-Frances; Moreno, Francisco A

    2015-06-01

    Marital separation is linked to negative mental and physical health; however, the strength of this link may vary across people. This study examined changes in respiratory sinus arrhythmia (RSA), used to assess cardiac vagal control, in recently separated adults (N = 79; M time since separation = 3.5 months). When reflecting on the separation, self-reported psychological distress following the separation interacted with a polymorphism in the serotonin transporter gene (5-HTTLPR) and a relevant single nucleotide polymorphism (SNP), rs25531, to predict RSA. Among people reporting emotional difficulties after the separation, those who were homozygous for the short allele had lower RSA levels while reflecting on their relationship than other genotypes. The findings, although limited by the relatively small sample size, are discussed in terms of how higher-sensitivity genotypes may interact with psychological responses to stress to alter physiology. © 2015 Society for Psychophysiological Research.

  20. Cognitive Control Structures in the Imitation Learning of Spatial Sequences and Rhythms-An fMRI Study.

    Science.gov (United States)

    Sakreida, Katrin; Higuchi, Satomi; Di Dio, Cinzia; Ziessler, Michael; Turgeon, Martine; Roberts, Neil; Vogt, Stefan

    2018-03-01

    Imitation learning involves the acquisition of novel motor patterns based on action observation (AO). We used event-related functional magnetic resonance imaging to study the imitation learning of spatial sequences and rhythms during AO, motor imagery (MI), and imitative execution in nonmusicians and musicians. While both tasks engaged the fronto-parietal mirror circuit, the spatial sequence task recruited posterior parietal and dorsal premotor regions more strongly. The rhythm task involved an additional network for auditory working memory. This partial dissociation supports the concept of task-specific mirror mechanisms. Two regions of cognitive control were identified: 1) dorsolateral prefrontal cortex (DLPFC) was found to be more strongly activated during MI of novel spatial sequences, which allowed us to extend the 2-level model of imitation learning by Buccino et al. (2004) to spatial sequences. 2) During imitative execution of both tasks, the posterior medial frontal cortex was robustly activated, along with the DLPFC, which suggests that both regions are involved in the cognitive control of imitation learning. The musicians' selective behavioral advantage for rhythm imitation was reflected cortically in enhanced sensory-motor processing during AO and by the absence of practice-related activation differences in DLPFC during rhythm execution. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. Directional semivariogram analysis to identify and rank controls on the spatial variability of fracture networks

    Science.gov (United States)

    Hanke, John R.; Fischer, Mark P.; Pollyea, Ryan M.

    2018-03-01

    In this study, the directional semivariogram is deployed to investigate the spatial variability of map-scale fracture network attributes in the Paradox Basin, Utah. The relative variability ratio (R) is introduced as the ratio of integrated anisotropic semivariogram models, and R is shown to be an effective metric for quantifying the magnitude of spatial variability for any two azimuthal directions. R is applied to a GIS-based data set comprising roughly 1200 fractures, in an area which is bounded by a map-scale anticline and a km-scale normal fault. This analysis reveals that proximity to the fault strongly influences the magnitude of spatial variability for both fracture intensity and intersection density within 1-2 km. Additionally, there is significant anisotropy in the spatial variability, which is correlated with trends of the anticline and fault. The direction of minimum spatial correlation is normal to the fault at proximal distances, and gradually rotates and becomes subparallel to the fold axis over the same 1-2 km distance away from the fault. We interpret these changes to reflect varying scales of influence of the fault and the fold on fracture network development: the fault locally influences the magnitude and variability of fracture network attributes, whereas the fold sets the background level and structure of directional variability.

  2. Rational construction of multiple interfaces in ternary heterostructure for efficient spatial separation and transfer of photogenerated carriers in the application of photocatalytic hydrogen evolution

    Science.gov (United States)

    Shi, Jian-Wen; Ma, Dandan; Zou, Yajun; Fan, Zhaoyang; Shi, Jinwen; Cheng, Linhao; Ji, Xin; Niu, Chunming

    2018-03-01

    The design of efficient and stable photocatalyst plays a critical role in the photocatalytic hydrogen evolution from water splitting. Herein, we develop a novel ZnS/CdS/ZnO ternary heterostructure by the in-situ sulfuration of CdS/ZnO, which includes four contact interfaces: CdS-ZnS interface, ZnS-ZnO interface, CdS-ZnO interface and ZnS-CdS-ZnO ternary interface, forming three charge carrier-transfer modes (type-I, type-II and direct Z-scheme) through five carrier-transfer pathways. As a result, the separation and transfer of photoexcited electron-hole pairs are promoted significantly, resulting in a high hydrogen evolution rate of 44.70 mmol h-1 g-1, which is 2, 3.7 and 8 times higher than those of binary heterostructures, CdS/ZnO, CdS/ZnS and ZnS/ZnO, respectively, and 26.5, 280 and 298 times higher than those of single CdS, ZnO and ZnS, respectively. As a counterpart ternary heterostructure, CdS/ZnS/ZnO contains only two interfaces: CdS-ZnS interface and ZnS-ZnO interface, which form two charge carrier-transfer modes (type-I and type-II) through two carrier-transfer pathways, leading to its much lower hydrogen evolution rate (27.25 mmol h-1 g-1) than ZnS/CdS/ZnO ternary heterostructure. This work is relevant for understanding the charge-transfer pathways between multi-interfaces in multicomponent heterojunctions.

  3. Hydrological and Biogeochemical Controls on Seasonal and Spatial Differences in Food Webs in the Everglades

    Science.gov (United States)

    Kendall, C.; Wankel, S. D.; Bemis, B. E.; Rawlik, P. S.; Krabbenhoft, D. P.; Lange, T.

    2002-05-01

    Stable isotopes can be used to determine the relative trophic positions of biota within a food web, and to improve our understanding of the biomagnification of contaminants. Plants at the base of the food web uptake dissolved organic carbon (DIC) and nitrogen (DIN) for growth, and their tissue reflects the isotopic composition of these sources. Animals then mirror the isotopic composition of the primary producers, as modified by consumer-diet fractionations at successive trophic steps. During 1995-99, we collected algae, macrophyte, invertebrate, and fish samples from 15 USGS sites in the Everglades and analyzed them for d13C and d15N with the goal of characterizing seasonal and spatial differences in food web relations. Carbon isotopes effectively distinguish between two main types of food webs: ones where algae is the dominant base of the food web, which are characteristic of relatively pristine marsh sites with long hydroperiods, and ones where macrophyte debris appears to be a significant source of nutrients, which are apparently characteristic of shorter hydroperiod sites, and nutrient-impacted marshes and canals. There usually is an inverse relation between d13C and d15N of organisms over time, especially in more pristine environments, reflecting seasonal changes in the d13C of DIC and the d15N of DIN. The d13C and d15N of algae also show strong positive correlations with seasonal changes in water levels. This variability is substantially damped up the food chain, probably because of the longer integration times of animals vs. plants. We speculate that these seasonal shifts in water level result in changes in biogeochemical reactions and nutrient levels, with corresponding variations in the d15N and d13C of biota. For example, small changes in water level may change the balance of photosynthesis, bacterial respiration, and atmospheric exchange reactions that control the d13C of DIC. Such changes will probably also affect the d15N of dissolved inorganic N (DIN

  4. A bio-inspired, microchanneled hydrogel with controlled spacing of cell adhesion ligands regulates 3D spatial organization of cells and tissue.

    Science.gov (United States)

    Lee, Min Kyung; Rich, Max H; Lee, Jonghwi; Kong, Hyunjoon

    2015-07-01

    Bioactive hydrogels have been extensively studied as a platform for 3D cell culture and tissue regeneration. One of the key desired design parameters is the ability to control spatial organization of biomolecules and cells and subsequent tissue in a 3D matrix. To this end, this study presents a simple but advanced method to spatially organize microchanneled, cell adherent gel blocks and non-adherent ones in a single construct. This hydrogel system was prepared by first fabricating a bimodal hydrogel in which the microscale, alginate gel blocks modified with cell adhesion peptides containing Arg-Gly-Asp sequence (RGD peptides), and those free of RGD peptides, were alternatingly presented. Then, anisotropically aligned microchannels were introduced by uniaxial freeze-drying of the bimodal hydrogel. The resulting gel system could drive bone marrow stromal cells to adhere to and differentiate into neuron and glial cells exclusively in microchannels of the alginate gel blocks modified with RGD peptides. Separately, the bimodal gel loaded with microparticles releasing vascular endothelial growth factor stimulated vascular growth solely into microchannels of the RGD-alginate gel blocks in vivo. These results were not attained by the bimodal hydrogel fabricated to present randomly oriented micropores. Overall, the bimodal gel system could regulate spatial organization of nerve-like tissue or blood vessels at sub-micrometer length scale. We believe that the hydrogel assembly demonstrated in this study will be highly useful in developing a better understanding of diverse cellular behaviors in 3D tissue and further improve quality of a wide array of engineered tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Multiple Scales of Control on the Structure and Spatial Distribution of Woody Vegetation in African Savanna Watersheds.

    Directory of Open Access Journals (Sweden)

    Nicholas R Vaughn

    Full Text Available Factors controlling savanna woody vegetation structure vary at multiple spatial and temporal scales, and as a consequence, unraveling their combined effects has proven to be a classic challenge in savanna ecology. We used airborne LiDAR (light detection and ranging to map three-dimensional woody vegetation structure throughout four savanna watersheds, each contrasting in geologic substrate and climate, in Kruger National Park, South Africa. By comparison of the four watersheds, we found that geologic substrate had a stronger effect than climate in determining watershed-scale differences in vegetation structural properties, including cover, height and crown density. Generalized Linear Models were used to assess the spatial distribution of woody vegetation structural properties, including cover, height and crown density, in relation to mapped hydrologic, topographic and fire history traits. For each substrate and climate combination, models incorporating topography, hydrology and fire history explained up to 30% of the remaining variation in woody canopy structure, but inclusion of a spatial autocovariate term further improved model performance. Both crown density and the cover of shorter woody canopies were determined more by unknown factors likely to be changing on smaller spatial scales, such as soil texture, herbivore abundance or fire behavior, than by our mapped regional-scale changes in topography and hydrology. We also detected patterns in spatial covariance at distances up to 50-450 m, depending on watershed and structural metric. Our results suggest that large-scale environmental factors play a smaller role than is often attributed to them in determining woody vegetation structure in southern African savannas. This highlights the need for more spatially-explicit, wide-area analyses using high resolution remote sensing techniques.

  6. Dynamic nuclear polarization and optimal control spatial-selective 13C MRI and MRS

    DEFF Research Database (Denmark)

    Vinding, Mads Sloth; Laustsen, Christoffer; Maximov, Ivan I.

    2013-01-01

    . This is achieved through the development of spatial-selective single-shot spiral-readout MRI and MRS experiments combined with dynamic nuclear polarization hyperpolarized [1-13C]pyruvate on a 4.7T pre-clinical MR scanner. The method stands out from related techniques by facilitating anatomic shaped region...

  7. Spectral, spatial and temporal control of high-power diode lasers through nonlinear optical feedback

    NARCIS (Netherlands)

    van Voorst, P.D.

    2008-01-01

    A high-power diode laser offers multi-Watt output power from a small and efficient device, which makes them an interesting source for numerous applications. The spatial and spectral output however, are of reduced quality which limits the applicability. This limited quality is connected to the design

  8. Herbs and spices: characterization and quantitation of biologically-active markers for routine quality control by multiple headspace solid-phase microextraction combined with separative or non-separative analysis.

    Science.gov (United States)

    Sgorbini, Barbara; Bicchi, Carlo; Cagliero, Cecilia; Cordero, Chiara; Liberto, Erica; Rubiolo, Patrizia

    2015-01-09

    Herbs and spices are used worldwide as food flavoring, thus determination of their identity, origin, and quality is mandatory for safe human consumption. An analysis strategy based on separative (HS-SPME-GC-MS) and non-separative (HS-SPME-MS) approaches is proposed for the volatile fraction of herbs and spices, for quality control and to quantify the aromatic markers with a single analysis directly on the plant material as such. Eight-to-ten lots of each of the following herbs/spices were considered: cloves (Syzygium aromaticum (L.) Merr. & Perry), American peppertree (Schinus molle L.), black pepper and white pepper (Piper nigrum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.) and thyme (Thymus vulgaris L.). Homogeneity, origin, and chemotypes of the investigated lots of each herb/spice were defined by fingerprinting, through statistical elaboration with principal component analysis (PCA). Characterizing aromatic markers were directly quantified on the solid matrix through multiple headspace extraction-HS-SPME (MHS-SPME). Reliable results were obtained with both separative and non-separative methods (where the latter were applicable); the two were in full agreement, RSD% ranging from 1.8 to 7.7% for eugenol in cloves, 2.2-18.4% for carvacrol+thymol in thyme, and 3.1-16.8% for thujones in sage. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. A power comparison of generalized additive models and the spatial scan statistic in a case-control setting

    Directory of Open Access Journals (Sweden)

    Ozonoff Al

    2010-07-01

    Full Text Available Abstract Background A common, important problem in spatial epidemiology is measuring and identifying variation in disease risk across a study region. In application of statistical methods, the problem has two parts. First, spatial variation in risk must be detected across the study region and, second, areas of increased or decreased risk must be correctly identified. The location of such areas may give clues to environmental sources of exposure and disease etiology. One statistical method applicable in spatial epidemiologic settings is a generalized additive model (GAM which can be applied with a bivariate LOESS smoother to account for geographic location as a possible predictor of disease status. A natural hypothesis when applying this method is whether residential location of subjects is associated with the outcome, i.e. is the smoothing term necessary? Permutation tests are a reasonable hypothesis testing method and provide adequate power under a simple alternative hypothesis. These tests have yet to be compared to other spatial statistics. Results This research uses simulated point data generated under three alternative hypotheses to evaluate the properties of the permutation methods and compare them to the popular spatial scan statistic in a case-control setting. Case 1 was a single circular cluster centered in a circular study region. The spatial scan statistic had the highest power though the GAM method estimates did not fall far behind. Case 2 was a single point source located at the center of a circular cluster and Case 3 was a line source at the center of the horizontal axis of a square study region. Each had linearly decreasing logodds with distance from the point. The GAM methods outperformed the scan statistic in Cases 2 and 3. Comparing sensitivity, measured as the proportion of the exposure source correctly identified as high or low risk, the GAM methods outperformed the scan statistic in all three Cases. Conclusions The GAM

  10. A power comparison of generalized additive models and the spatial scan statistic in a case-control setting.

    Science.gov (United States)

    Young, Robin L; Weinberg, Janice; Vieira, Verónica; Ozonoff, Al; Webster, Thomas F

    2010-07-19

    A common, important problem in spatial epidemiology is measuring and identifying variation in disease risk across a study region. In application of statistical methods, the problem has two parts. First, spatial variation in risk must be detected across the study region and, second, areas of increased or decreased risk must be correctly identified. The location of such areas may give clues to environmental sources of exposure and disease etiology. One statistical method applicable in spatial epidemiologic settings is a generalized additive model (GAM) which can be applied with a bivariate LOESS smoother to account for geographic location as a possible predictor of disease status. A natural hypothesis when applying this method is whether residential location of subjects is associated with the outcome, i.e. is the smoothing term necessary? Permutation tests are a reasonable hypothesis testing method and provide adequate power under a simple alternative hypothesis. These tests have yet to be compared to other spatial statistics. This research uses simulated point data generated under three alternative hypotheses to evaluate the properties of the permutation methods and compare them to the popular spatial scan statistic in a case-control setting. Case 1 was a single circular cluster centered in a circular study region. The spatial scan statistic had the highest power though the GAM method estimates did not fall far behind. Case 2 was a single point source located at the center of a circular cluster and Case 3 was a line source at the center of the horizontal axis of a square study region. Each had linearly decreasing logodds with distance from the point. The GAM methods outperformed the scan statistic in Cases 2 and 3. Comparing sensitivity, measured as the proportion of the exposure source correctly identified as high or low risk, the GAM methods outperformed the scan statistic in all three Cases. The GAM permutation testing methods provide a regression

  11. Effectiveness of the custom-mold room temperature vulcanizing silicone toe separator on hallux valgus: A prospective, randomized single-blinded controlled trial.

    Science.gov (United States)

    Chadchavalpanichaya, Navaporn; Prakotmongkol, Voraluck; Polhan, Nattapong; Rayothee, Pitchaya; Seng-Iad, Sirirat

    2018-04-01

    Silicone toe separator is considered as a conservative treatment for hallux valgus. The prefabricated toe separator does not fit all. However, effectiveness in prescription of the custom-mold toe separator is still unknown. To investigate the effect of using a custom-mold room temperature vulcanizing silicone toe separator to decrease hallux valgus angle and hallux pain. The compliances, complications, and satisfactions of toe separator were also explored. A prospective, randomized single-blinded controlled trial. A total of 90 patients with a moderate degree of hallux valgus were enrolled in a study at the Foot Clinic, Siriraj Hospital, Thailand. Patients were randomized into two groups; the study group was prescribed a custom-mold room temperature vulcanizing silicone toe separator for 6 h per night for 12 months. Patients in both groups received proper foot care and shoes and were permitted to continue drug treatment. In total, 40 patients in the study group and 39 patients in the control group completed the study. The hallux valgus angle was obtained through radiographic measurement. At month 12, both groups had significant differences in mean hallux valgus angle with a decrease of 3.3° ± 2.4° for the study group and increase of 1.9° ± 1.9° for the control group. There were statistically significant differences of hallux valgus angle between the two groups ( p Hallux pain was decreased in the study group. A custom-mold room temperature vulcanizing silicone toe separator can decrease hallux valgus angle and pain with no serious complications. Clinical relevance The custom-mold room temperature vulcanizing silicone toe separator for treatment of hallux valgus reduces deformity and hallux pain.

  12. Quasi-static analysis and control of planer and spatial bending fluidic actuator

    OpenAIRE

    Chang, Benjamin Che-Ming

    2011-01-01

    This work presents a novel silicone-based millimetre scale bending fluidic actuator. Two designs of the bending fluidic actuator are studied: a planer actuator that bends about one axis; and a spatial actuator able to bend about two orthogonal axes. The unique parallel micro-channel design of the fluidic actuators enables operation at low working pressures, while at the same time having a very limited thickness expansion during pressurization. The fluidic actuators can be easily scaled to des...

  13. Understanding the neural control of ingestive behaviors: helping to separate cause from effect with dehydration-associated anorexia.

    Science.gov (United States)

    Watts, A G

    2000-06-01

    Eating and drinking are motivated behaviors that are made up of coordinated sets of neuroendocrine, autonomic, and behavioral motor events. Although the spinal cord, hindbrain, and hypothalamus contain the motor neurons and circuitry sufficient to maintain the reflex parts of these motor events, inputs from the telencephalon are required to furnish the behavioral components with a motivated (goal-directed) character. Each of these motor events derives from the complex interaction of a variety of sensory inputs with groups of neural networks whose components are distributed throughout the brain and collectively support motor expression and coordination. At a first approximation based on a variety of data, these networks can be divided into three groups: networks that stimulate, those that inhibit, and those that disinhibit motor functions. A fourth contributor is the circadian timing signal that originates in the hypothalamic suprachiasmatic nucleus and provides the temporal anchor for the expression of all behaviors. This article discusses the nature of these networks using neuroanatomical (tract-tracing and neuropeptide in situ hybridization), endocrine, and behavioral evidence from a variety of experimental models. A persistent problem when studying the control of food intake from a neural systems perspective has been the difficulty in separating those neuronal changes that result in hunger from those that are as a consequence of eating. To address this problem, dehydration-associated anorexia is presented as a particularly useful experimental model because it can be used to distinguish between neural mechanisms underlying anorexia and those changes that occur as a consequence of anorexia. The article concludes by highlighting the potential role of neuropeptidergic action in the operation of these networks, using forebrain neuropeptidergic innervation of the parabrachial nucleus as an example. Copyright 2000 Academic Press.

  14. Spatial distribution of heavy metals in the surface soil of source-control stormwater infiltration devices - Inter-site comparison.

    Science.gov (United States)

    Tedoldi, Damien; Chebbo, Ghassan; Pierlot, Daniel; Branchu, Philippe; Kovacs, Yves; Gromaire, Marie-Christine

    2017-02-01

    Stormwater runoff infiltration brings about some concerns regarding its potential impact on both soil and groundwater quality; besides, the fate of contaminants in source-control devices somewhat suffers from a lack of documentation. The present study was dedicated to assessing the spatial distribution of three heavy metals (copper, lead, zinc) in the surface soil of ten small-scale infiltration facilities, along with several physical parameters (soil moisture, volatile matter, variable thickness of the upper horizon). High-resolution samplings and in-situ measurements were undertaken, followed by X-ray fluorescence analyses and spatial interpolation. Highest metal accumulation was found in a relatively narrow area near the water inflow zone, from which concentrations markedly decreased with increasing distance. Maximum enrichment ratios amounted to >20 in the most contaminated sites. Heavy metal patterns give a time-integrated vision of the non-uniform infiltration fluxes, sedimentation processes and surface flow pathways within the devices. This element indicates that the lateral extent of contamination is mainly controlled by hydraulics. The evidenced spatial structure of soil concentrations restricts the area where remediation measures would be necessary in these systems, and suggests possible optimization of their hydraulic functioning towards an easier maintenance. Heterogeneous upper boundary conditions should be taken into account when studying the fate of micropollutants in infiltration facilities with either mathematical modeling or soil coring field surveys. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Precise and Arbitrary Deposition of Biomolecules onto Biomimetic Fibrous Matrices for Spatially Controlled Cell Distribution and Functions.

    Science.gov (United States)

    Jia, Chao; Luo, Bowen; Wang, Haoyu; Bian, Yongqian; Li, Xueyong; Li, Shaohua; Wang, Hongjun

    2017-09-01

    Advances in nano-/microfabrication allow the fabrication of biomimetic substrates for various biomedical applications. In particular, it would be beneficial to control the distribution of cells and relevant biomolecules on an extracellular matrix (ECM)-like substrate with arbitrary micropatterns. In this regard, the possibilities of patterning biomolecules and cells on nanofibrous matrices are explored here by combining inkjet printing and electrospinning. Upon investigation of key parameters for patterning accuracy and reproducibility, three independent studies are performed to demonstrate the potential of this platform for: i) transforming growth factor (TGF)-β1-induced spatial differentiation of fibroblasts, ii) spatiotemporal interactions between breast cancer cells and stromal cells, and iii) cancer-regulated angiogenesis. The results show that TGF-β1 induces local fibroblast-to-myofibroblast differentiation in a dose-dependent fashion, and breast cancer clusters recruit activated stromal cells and guide the sprouting of endothelial cells in a spatially resolved manner. The established platform not only provides strategies to fabricate ECM-like interfaces for medical devices, but also offers the capability of spatially controlling cell organization for fundamental studies, and for high-throughput screening of various biomolecules for stem cell differentiation and cancer therapeutics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Sequence control of phase separation and dewetting in PS/PVME blend thin films by changing molecular weight of PS.

    Science.gov (United States)

    Xia, Tian; Qin, Yaping; Huang, Yajiang; Huang, Ting; Xu, Jianhui; Li, Youbing

    2016-11-28

    The morphology evolution mechanism of polystyrene (PS)/poly (vinyl methyl ether) (PVME) blend thin films with different PS molecular weights (M w ) was studied. It was found that the morphology evolution was closely related to the molecular weight asymmetry between PS and PVME. In the film where M w (PS) ≈ M w (PVME), dewetting happened at the interface between the bottom layer and substrate after SD phase separation. While in the film where M w (PS) > M w (PVME), dewetting happened at the interface between the middle PS/PVME blend layer and bottom PVME layer near the substrate prior to phase separation. The different sequences of phase separation and dewetting and different interface for dewetting occurrence were studied by regarding the competitive effects of viscoelasticity contrast between polymer components and preferential wetting between PVME and the substrate. The viscoelastic nature of the PS component played a crucial role in the sequence of phase separation and dewetting.

  17. Field assessment of a novel spatial repellent for malaria control: a feasibility and acceptability study in Mondulkiri, Cambodia.

    Science.gov (United States)

    Liverani, Marco; Charlwood, Jacques Derek; Lawford, Harriet; Yeung, Shunmay

    2017-10-13

    Large-scale use of insecticide-treated nets and indoor residual spraying have contributed to a significant decrease in malaria transmission worldwide. Further reduction and progress towards elimination, however, require complementary control measures which can address the remaining gaps in protection from mosquito bites. Following the development of novel pyrethroids with high knockdown effects on malaria vectors, programmatic use of spatial repellents has been suggested as one potential strategy to fill the gaps. This report explores social and contextual factors that may influence the relevance, uptake and sustainable use of a spatial repellent in two remote villages in Mondulkiri province, Cambodia, with endemic malaria transmission. The repellent consisted of polyethylene emanators, held in an open plastic frame and impregnated with 10% metofluthrin. In a baseline survey, 90.9% of households in Ou Chra (n = 30/33) and 96.6% in Pu Cha (n = 57/59) were interviewed. Behavioural data were collected for all household occupants (n = 448). In both villages, there were times and places in which people remained exposed to mosquito bites. Prior to the installation of the repellent, 50.6 and 59.5% of respondents noted that bites occurred "very often" inside the house and in the outdoor area surrounding the house, respectively. Indoor biting was reported to occur more frequently in the evening, followed by at night, while outdoor biting occurred more frequently in the early morning. In a follow-up survey, spatial repellents were well received in both villages, although 63.2% of respondents would not replace bed nets with repellents. Most participants (96.6%) were willing to use the product again; the mean willingness to pay was US$ 0.3 per unit. A preference for local procurement methods emerged. Widespread use of spatial repellents would not fill all protective gaps, but, if their entomological efficacy can be ascertained, outdoor application has the potential to

  18. A separator

    Energy Technology Data Exchange (ETDEWEB)

    Prokopyuk, S.G.; Dyachenko, A.Ye.; Mukhametov, M.N.; Prokopov, O.I.

    1982-01-01

    A separator is proposed which contains separating slanted plates and baffle plates installed at a distance to them at an acute angle to them. To increase the effectiveness of separating a gas and liquid stream and the throughput through reducing the secondary carry away of the liquid drops and to reduce the hydraulic resistance, as well, openings are made in the plates. The horizontal projections of each opening from the lower and upper surfaces of the plate do not overlap each other.

  19. Does age matter? Controls on the spatial organization of age and life expectancy in hillslopes, and implications for transport parameterization using rSAS

    Science.gov (United States)

    Kim, M.; Harman, C. J.; Troch, P. A. A.

    2017-12-01

    Hillslopes have been extensively explored as a natural fundamental unit for spatially-integrated hydrologic models. Much of this attention has focused on their use in predicting the quantity of discharge, but hillslope-based models can potentially be used to predict the composition of discharge (in terms of age and chemistry) if they can be parameterized terms of measurable physical properties. Here we present advances in the use of rank StorAge Selection (rSAS) functions to parameterize transport through hillslopes. These functions provide a mapping between the distribution of water ages in storage and in outfluxes in terms of a probability distribution over storage. It has previously been shown that rSAS functions are related to the relative partitioning and arrangement of flow pathways (and variabilities in that arrangement), while separating out the effect of changes in the overall rate of fluxes in and out. This suggests that rSAS functions should have a connection to the internal organization of flow paths in a hillslope.Using a combination of numerical modeling and theoretical analysis we examined: first, the controls of physical properties on internal spatial organization of age (time since entry), life expectancy (time to exit), and the emergent transit time distribution and rSAS functions; second, the possible parameterization of the rSAS function using the physical properties. The numerical modeling results showed the clear dependence of the rSAS function forms on the physical properties and relations between the internal organization and the rSAS functions. For the different rates of the exponential saturated hydraulic conductivity decline with depth the spatial organization of life expectancy varied dramatically and determined the rSAS function forms, while the organizaiton of the age showed less qualitative differences. Analytical solutions predicting this spatial organization and the resulting rSAS function were derived for simplified systems. These

  20. Spatial diversification of agroecosystems to enhance biological control and other regulating services: An agroecological perspective.

    Science.gov (United States)

    Hatt, Séverin; Boeraeve, Fanny; Artru, Sidonie; Dufrêne, Marc; Francis, Frédéric

    2018-04-15

    Spatial diversification of crop and non-crop habitats in farming systems is promising for enhancing natural regulation of insect pests. Nevertheless, results from recent syntheses show variable effects. One explanation is that the abundance and diversity of pests and natural enemies are affected by the composition, design and management of crop and non-crop habitats. Moreover, interactions between both local and landscape elements and practices carried out at different spatial scales may affect the regulation of insect pests. Hence, research is being conducted to understand these interdependencies. However, insects are not the only pests and pests are not the only elements to regulate in agroecosystems. Broadening the scope could allow addressing multiple issues simultaneously, but also solving them together by enhancing synergies. Indeed, spatial diversification of crop and non-crop habitats can allow addressing the issues of weeds and pathogens, along with being beneficial to several other regulating services like pollination, soil conservation and nutrient cycling. Although calls rise to develop multifunctional landscapes that optimize the delivery of multiple ecosystem services, it still represents a scientific challenge today. Enhancing interdisciplinarity in research institutions and building interrelations between scientists and stakeholders may help reach this goal. Despite obstacles, positive results from research based on such innovative approaches are encouraging for engaging science in this path. Hence, the aim of the present paper is to offer an update on these issues by exploring the most recent findings and discussing these results to highlight needs for future research. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Isotope separation

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1979-01-01

    A method of isotope separation is described which involves the use of a laser photon beam to selectively induce energy level transitions of an isotope molecule containing the isotope to be separated. The use of the technique for 235 U enrichment is demonstrated. (UK)

  2. New separation technique. Catalytically functionated separation membrane

    Energy Technology Data Exchange (ETDEWEB)

    Urgami, Tadashi [Kansai Univ., Osaka (Japan)

    1989-02-01

    This report introduces research examples, showing the fundamental principle of the membrane by separating the catalytically functionated separation membrane into enzyme fixing separation membrane, polymerized metal complex separation membrane and polymer catalyst separation membrane. This membrane can achieve both functions of separation and catalytic reaction simultaneously and has sufficient possibility to combine powerful functions. Enzyme fixing separation membrane is prepared by carrier combination method, bridging method or covering method and the enzyme fixing method with polymerized complex in which enzyme is controlled to prevent the activity lowering as much as possible and enzyme is fixed from an aqueous solution into polymer membrane. This membrane is applied to the continuous manufacturing of invert sugar from cane sugar and adsorption and removing of harmful substances from blood by utilizing both micro-capsuled urease and active carbon. Alginic acid-copper (II) complex membrane is used for the polymerized metal complex membrane and polystyrene sulfonate membrane is used for the polymer catalyst separation membrane. 28 refs., 4 figs., 1 tabs.

  3. Spatial-Temporal Patterns and Controls of Evapotranspiration across the Tibetan Plateau (2000–2012

    Directory of Open Access Journals (Sweden)

    Hao Zhang

    2017-01-01

    Full Text Available Evapotranspiration (ET is a key factor to further our understanding of climate change processes, especially on the Tibetan Plateau, which is sensitive to global change. Herein, the spatial patterns of ET are examined, and the effects of environmental factors on ET at different scales are explored from the years 2000 to 2012. The results indicated that a steady trend in ET was detected over the past decade. Meanwhile, the spatial distribution shows an increase of ET from the northwest to the southeast, and the rate of change in ET is lower in the middle part of the Tibetan Plateau. Besides, the positive effect of radiation on ET existed mainly in the southwest. Based on the environment gradient transects, the ET had positive correlations with temperature (R>0.85, p 0.89, p 0.75, p < 0.0001, but a negative correlation between ET and radiation (R = 0.76, p < 0.0001 was observed. We also found that the relationships between environmental factors and ET differed in the different grassland ecosystems, which indicated that vegetation type is one factor that can affect ET. Generally, the results indicate that ET can serve as a valuable ecological indicator.

  4. Sun-controlled spatial and time-dependent cycles in the climatic/weather system

    International Nuclear Information System (INIS)

    Njau, E.C.

    1990-11-01

    We show, on the basis of meteorological records, that certain spatial and time-dependent cycles exist in the earth-atmosphere system (EAS). These cycles seem to be associated with sunspot cycles and hence have been referred to in the text as ''data-derived solar cycles''. Our analysis establishes three important characteristics of the data-derived solar cycles (DSC's). Firstly the crests and troughs of these data-derived solar cycles are mostly latitudinally aligned and have (zonal) spatial wavelengths greater than about 7 degrees of longitude. Secondly the DSC's have periods mostly lying between 6 years and 12 years. In certain stations, some DSC's coincide quite well with corresponding sunspot cycles. Thirdly the crests and troughs of the DSC's drift eastwards at speeds exceeding about 1.5 longitude degrees per year. Furthermore, these DSC's display peak-to-peak amplitudes of about 2 deg. C along East Africa. On the basis of earlier work and bearing in mind the considerable temperature-dependence of the stratospheric ozone layer, we predict existence of latitudinally aligned enhancement and depletion structures (corresponding to the DSC's) in the stratospheric ozone layer within cloudless midnight-to-predawn sectors. (author). 9 refs, 5 figs

  5. Spatial Targeting for Bovine Tuberculosis Control: Can the Locations of Infected Cattle Be Used to Find Infected Badgers?

    Directory of Open Access Journals (Sweden)

    Catherine M Smith

    Full Text Available Bovine tuberculosis is a disease of historical importance to human health in the UK that remains a major animal health and economic issue. Control of the disease in cattle is complicated by the presence of a reservoir species, the Eurasian badger. In spite of uncertainty in the degree to which cattle disease results from transmission from badgers, and opposition from environmental groups, culling of badgers has been licenced in two large areas in England. Methods to limit culls to smaller areas that target badgers infected with TB whilst minimising the number of uninfected badgers culled is therefore of considerable interest. Here, we use historical data from a large-scale field trial of badger culling to assess two alternative hypothetical methods of targeting TB-infected badgers based on the distribution of cattle TB incidents: (i a simple circular 'ring cull'; and (ii geographic profiling, a novel technique for spatial targeting of infectious disease control that predicts the locations of sources of infection based on the distribution of linked cases. Our results showed that both methods required coverage of very large areas to ensure a substantial proportion of infected badgers were removed, and would result in many uninfected badgers being culled. Geographic profiling, which accounts for clustering of infections in badger and cattle populations, produced a small but non-significant increase in the proportion of setts with TB-infected compared to uninfected badgers included in a cull. It also provided no overall improvement at targeting setts with infected badgers compared to the ring cull. Cattle TB incidents in this study were therefore insufficiently clustered around TB-infected badger setts to design an efficient spatially targeted cull; and this analysis provided no evidence to support a move towards spatially targeted badger culling policies for bovine TB control.

  6. Spatial pattern evolution of Aedes aegypti breeding sites in an Argentinean city without a dengue vector control programme

    Directory of Open Access Journals (Sweden)

    Manuel O. Espinosa

    2016-11-01

    Full Text Available The main objective of this study was to obtain and analyse the space-time dynamics of Aedes aegypti breeding sites in Clorinda City, Formosa Province, Argentina coupled with landscape analysis using the maximum entropy approach in order to generate a dengue vector niche model. In urban areas, without vector control activities, 12 entomologic (larval samplings were performed during three years (October 2011 to October 2014. The entomologic surveillance area represented 16,511 houses. Predictive models for Aedes distribution were developed using vector breeding abundance data, density analysis, clustering and geoprocessing techniques coupled with Earth observation satellite data. The spatial analysis showed a vector spatial distribution pattern with clusters of high density in the central region of Clorinda with a well-defined high-risk area in the western part of the city. It also showed a differential temporal behaviour among different areas, which could have implications for risk models and control strategies at the urban scale. The niche model obtained for Ae. aegypti, based on only one year of field data, showed that 85.8% of the distribution of breeding sites is explained by the percentage of water supply (48.2%, urban distribution (33.2%, and the percentage of urban coverage (4.4%. The consequences for the development of control strategies are discussed with reference to the results obtained using distribution maps based on environmental variables.

  7. Spatial pattern evolution of Aedes aegypti breeding sites in an Argentinean city without a dengue vector control programme.

    Science.gov (United States)

    Espinosa, Manuel O; Polop, Francisco; Rotela, Camilo H; Abril, Marcelo; Scavuzzo, Carlos M

    2016-11-21

    The main objective of this study was to obtain and analyse the space-time dynamics of Aedes aegypti breeding sites in Clorinda City, Formosa Province, Argentina coupled with landscape analysis using the maximum entropy approach in order to generate a dengue vector niche model. In urban areas, without vector control activities, 12 entomologic (larval) samplings were performed during three years (October 2011 to October 2014). The entomologic surveillance area represented 16,511 houses. Predictive models for Aedes distribution were developed using vector breeding abundance data, density analysis, clustering and geoprocessing techniques coupled with Earth observation satellite data. The spatial analysis showed a vector spatial distribution pattern with clusters of high density in the central region of Clorinda with a well-defined high-risk area in the western part of the city. It also showed a differential temporal behaviour among different areas, which could have implications for risk models and control strategies at the urban scale. The niche model obtained for Ae. aegypti, based on only one year of field data, showed that 85.8% of the distribution of breeding sites is explained by the percentage of water supply (48.2%), urban distribution (33.2%), and the percentage of urban coverage (4.4%). The consequences for the development of control strategies are discussed with reference to the results obtained using distribution maps based on environmental variables.

  8. A new approach to control of xenon spatial oscillation during load follow operation via robust servo systems

    International Nuclear Information System (INIS)

    Ukai, Hiroyuki; Iwazumi, Tetsuo

    1994-01-01

    The control problem of xenon-induced spatial oscillations of PWR in the axial direction during a load following operation is investigated. The system models are described by a one-group diffusion equation with xenon and temperature feed-backs, iodine and xenon dynamic equations, and heat conductions processes. Control is implemented by the full-length and the part-length control rods and the boron concentration. In order to achieve the control purpose, control models are formulated as the design problem of robust servo systems for distributed parameter reactor systems. The total thermal power and the axial offset are chosen as outputs to be controlled. The control systems consist of servo compensators and stabilizing compensators. They are designed based on the finite-dimensional systems which are constructed by linearizing around steady states, approximately by the Galerkin method, and reducing dimensions via the singular perturbation method. A new and simple computational algorithm to obtain an approximate solution of a steady-state neutron balance is developed via the perturbation method. Some results of numerical simulations are shown in order to discuss the effectiveness of the theory developed in this paper. In particular, it is shown that the designed servo systems are robust against model errors with linearization and modal truncation

  9. Solutions to the cocktail party problem in insects: selective filters, spatial release from masking and gain control in tropical crickets.

    Directory of Open Access Journals (Sweden)

    Arne K D Schmidt

    Full Text Available Insects often communicate by sound in mixed species choruses; like humans and many vertebrates in crowded social environments they thus have to solve cocktail-party-like problems in order to ensure successful communication with conspecifics. This is even more a problem in species-rich environments like tropical rainforests, where background noise levels of up to 60 dB SPL have been measured.Using neurophysiological methods we investigated the effect of natural background noise (masker on signal detection thresholds in two tropical cricket species Paroecanthus podagrosus and Diatrypa sp., both in the laboratory and outdoors. We identified three 'bottom-up' mechanisms which contribute to an excellent neuronal representation of conspecific signals despite the masking background. First, the sharply tuned frequency selectivity of the receiver reduces the amount of masking energy around the species-specific calling song frequency. Laboratory experiments yielded an average signal-to-noise ratio (SNR of -8 dB, when masker and signal were broadcast from the same side. Secondly, displacing the masker by 180° from the signal improved SNRs by further 6 to 9 dB, a phenomenon known as spatial release from masking. Surprisingly, experiments carried out directly in the nocturnal rainforest yielded SNRs of about -23 dB compared with those in the laboratory with the same masker, where SNRs reached only -14.5 and -16 dB in both species. Finally, a neuronal gain control mechanism enhances the contrast between the responses to signals and the masker, by inhibition of neuronal activity in interstimulus intervals.Thus, conventional speaker playbacks in the lab apparently do not properly reconstruct the masking noise situation in a spatially realistic manner, since under real world conditions multiple sound sources are spatially distributed in space. Our results also indicate that without knowledge of the receiver properties and the spatial release mechanisms the

  10. Implementation of an expert system for xenon spatial control in pressurized-water reactors

    International Nuclear Information System (INIS)

    Chung, S.K.

    1988-01-01

    Control of the axial xenon oscillations is a knowledge- and experience-intensive activity for reactor operators. To aid reactor operators in the control of axial xenon oscillations, an advisory expert system was developed. A rule-based expert system shell, INSIGHT2+, was used to build the expert system which was interfaced with a microcomputer-based core control model of a pressurized-water reactor, graphic engine, and data base. A core control model described by one-group diffusion theory with moderator temperature and xenon feedbacks was used to develop heuristic control rules and to test the system. Full- and part-length control rods, boron concentration, and coolant inlet temperature were considered as control variables of the core control model. This expert system consists of a search space: the set of possible power level and power shape patterns. The search space was made by combining the following core state variables: the sign of relative power and axial offset (AO) error, sign of the rate of change of power level and AO, and magnitude of relative power and AO error

  11. Dynamics of weed populations : spatial pattern formation and implications for control

    NARCIS (Netherlands)

    Wallinga, J.

    1998-01-01

    Modelling studies were carried out to analyse spatio-temporal dynamics of annual weed populations and to identify the key factors that determine the long-term herbicide use of weed control programmes. Three different weed control programmes were studied.

    In the first weed

  12. Independent control strategy of two DC-link voltages for separate MPPTs in transformerless photovoltaic systems using neutral-point-clamped inverters

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Lee, Kyo-Beum

    2014-01-01

    To improve the efficiency of the photovoltaic (PV) system, the centralized topology using three-level inverters are widely used. In this system, PV modules are separately connected to the split DC-links. This causes a decrease of maximum power point tracking (MPPT) efficiency under the partial...... shading condition. This paper proposes an independent control of two DC-link voltages for separate MPPT of each PV module in three-level inverters. The proposed method is simply implemented by adding or subtracting the time-offset to the three-phase turn-on times and modifying the reference voltages...

  13. Computerized precision control of a synchronous high voltage discharge switch for the beam separation system of the LEP e+/e- collider

    International Nuclear Information System (INIS)

    Dieperink, J.H.; Finnigan, A.; Kalbreier, W.; Keizer, R.L.; Laffin, M.; Mertens, V.

    1989-01-01

    Electrostatic separators are used to separate the beams in LEP. The counter-rotating beams are eventually brought into collision in the four low beta insertions, using switches to discharge simultaneously four high voltage (HV) circuits. Each switch consists of four spark gaps mounted in a pressure vessel. A reduction of the gap widths below the self ignition instance by electric motors results in the initiation of the discharges. Synchronization is ensured by the electrical coupling of the electrodes connected to the ground. The design and performance of the computerized precision control of the discharge switch are described. The dynamic characteristics of the prototype switch are also presented. 5 refs., 5 figs

  14. Microparticle Separation by Cyclonic Separation

    Science.gov (United States)

    Karback, Keegan; Leith, Alexander

    2017-11-01

    The ability to separate particles based on their size has wide ranging applications from the industrial to the medical. Currently, cyclonic separators are primarily used in agriculture and manufacturing to syphon out contaminates or products from an air supply. This has led us to believe that cyclonic separation has more applications than the agricultural and industrial. Using the OpenFoam computational package, we were able to determine the flow parameters of a vortex in a cyclonic separator in order to segregate dust particles to a cutoff size of tens of nanometers. To test the model, we constructed an experiment to separate a test dust of various sized particles. We filled a chamber with Arizona test dust and utilized an acoustic suspension technique to segregate particles finer than a coarse cutoff size and introduce them into the cyclonic separation apparatus where they were further separated via a vortex following our computational model. The size of the particles separated from this experiment will be used to further refine our model. Metropolitan State University of Denver, Colorado University of Denver, Dr. Randall Tagg, Dr. Richard Krantz.

  15. Spatial separation of electrons and holes for enhancing the gas-sensing property of a semiconductor: ZnO/ZnSnO3 nanorod arrays prepared by a hetero-epitaxial growth

    Science.gov (United States)

    Wang, Ying; Gao, Peng; Sha, Linna; Chi, Qianqian; Yang, Lei; Zhang, Jianjiao; Chen, Yujin; Zhang, Milin

    2018-04-01

    The construction of semiconductor composites is known as a powerful method used to realize the spatial separation of electrons and the holes in them, which can result in more electrons or holes and increase the dispersion of oxygen ions ({{{{O}}}2}- and O - ) (one of the most critical factors for their gas-sensing properties) on the surface of the semiconductor gas sensor. In this work, using 1D ZnO/ZnSnO3 nanoarrays as an example, which are prepared through a hetero-epitaxial growing process to construct a chemically bonded interface, the above strategy to attain a better semiconductor gas-sensing property has been realized. Compared with single ZnSnO3 nanotubes and no-matching ZnO/ZnSnO3 nanoarrays gas sensors, it has been proven by x-ray photoelectron spectroscopy and photoluminescence spectrum examination that the as-obtained ZnO/ZnSnO3 sensor showed a greatly increased quantity of active surface electrons with exceptional responses to trace target gases and much lower optimum working temperatures (less than about 170 °C). For example, the as-obtained ZnO/ZnSnO3 sensor exhibited an obvious response and short response/recovery time (less than 10 s) towards trace H2S gas (a detection limit down to 700 ppb). The high responses and dynamic repeatability observed in these sensors reveal that the strategy based on the as-presented electron and hole separation is reliable for improving the gas-sensing properties of semiconductors.

  16. Lanthanide-activated Na5Gd9F32 nanocrystals precipitated from a borosilicate glass: Phase-separation-controlled crystallization and optical property

    International Nuclear Information System (INIS)

    Chen, Daqin; Wan, Zhongyi; Zhou, Yang; Chen, Yan; Yu, Hua; Lu, Hongwei; Ji, Zhenguo; Huang, Ping

    2015-01-01

    Highlights: • Na 5 Gd 9 F 32 nanocrystals embedded glass ceramics were fabricated for the first time. • Such glass ceramics were achieved by phase-separation-controlled crystallization. • Elemental mapping evidenced the segregation of activators into the Na 5 Gd 9 F 32 lattice. • Luminescent color could be tuned by controlling glass crystallization temperature. - Abstract: Lanthanide-activated cubic Na 5 Gd 9 F 32 nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na 5 Gd 9 F 32 lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb 3+ /Er 3+ ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties

  17. Isotopic separation

    International Nuclear Information System (INIS)

    Castle, P.M.

    1979-01-01

    This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235 U from other uranium isotopes including 238 U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF 6 molecules in HBr molecules so as to collapse the V 3 vibrational mode of the UF 6 molecule the 235 UF 6 molecules are selectively excited to promote reduction of UF 6 molecules containing 235 U and facilitate separation. (UK)

  18. Isotopic separation

    International Nuclear Information System (INIS)

    Chen, C.L.

    1979-01-01

    Isotopic species in an isotopic mixture including a first species having a first isotope and a second species having a second isotope are separated by selectively exciting the first species in preference to the second species and then reacting the selectively excited first species with an additional preselected radiation, an electron or another chemical species so as to form a product having a mass different from the original species and separating the product from the balance of the mixture in a centrifugal separating device such as centrifuge or aerodynamic nozzle. In the centrifuge the isotopic mixture is passed into a rotor where it is irradiated through a window. Heavier and lighter components can be withdrawn. The irradiated mixture experiences a large centrifugal force and is separated in a deflection area into lighter and heavier components. (UK)

  19. Separations chemistry

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Results of studies on the photochemistry of aqueous Pu solutions and the stability of iodine in liquid and gaseous CO 2 are reported. Progress is reported in studies on: the preparation of macroporous bodies filled with oxides and sulfides to be used as adsorbents; the beneficiation of photographic wastes; the anion exchange adsorption of transition elements from thiosulfate solutions; advanced filtration applications of energy significance; high-resolution separations; and, the examination of the separation agents, octylphenylphosphoric acid (OPPA) and trihexyl phosphate (THP)

  20. Isotopic separation

    International Nuclear Information System (INIS)

    Chen, C.L.

    1982-01-01

    A method is described for separating isotopes in which photo-excitation of selected isotope species is used together with the reaction of the excited species with postive ions of predetermined ionization energy, other excited species, or free electrons to produce ions or ion fragments of the selected species. Ions and electrons are produced by an electrical discharge, and separation is achieved through radial ambipolar diffusion, electrostatic techniques, or magnetohydrodynamic methods

  1. Spatial and temporal control of the diazonium modification of sp2 carbon surfaces.

    Science.gov (United States)

    Kirkman, Paul M; Güell, Aleix G; Cuharuc, Anatolii S; Unwin, Patrick R

    2014-01-08

    Interest in the controlled chemical functionalization of sp(2) carbon materials using diazonium compounds has been recently reignited, particularly as a means to generate a band gap in graphene. We demonstrate local diazonium modification of pristine sp(2) carbon surfaces, with high control, at the micrometer scale through the use of scanning electrochemical cell microscopy (SECCM). Electrochemically driven diazonium patterning is investigated at a range of driving forces, coupled with surface analysis using atomic force microscopy (AFM) and Raman spectroscopy. We highlight how the film density, level of sp(2)/sp(3) rehybridization and the extent of multilayer formation can be controlled, paving the way for the use of localized electrochemistry as a route to controlled diazonium modification.

  2. Spatially optimal habitat management for enhancing natural control of an invasive agricultural pest: soybean aphid

    NARCIS (Netherlands)

    Zhang, W.; Werf, van der W.; Swinton, S.M.

    2010-01-01

    By their direct effects on private profitability, invasive agricultural pests create special incentives for management that set them apart from other categories of invasive species. One attractive nonchemical management approach for agricultural pests relies upon biological control by natural

  3. HYBRID ALARM SYSTEMS: COMBINING SPATIAL ALARMS AND ALARM LISTS FOR OPTIMIZED CONTROL ROOM OPERATION

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Boring; J.J. Persensky

    2012-07-01

    The US Department of Energy (DOE) is sponsoring research, development, and deployment on Light Water Reactor Sustainability (LWRS), in which the Idaho National Laboratory (INL) is working closely with nuclear utilities to develop technologies and solutions to help ensure the safe operational life extension of current nuclear power plants. One of the main areas of focus is control room modernization. Within control room modernization, alarm system upgrades present opportunities to meet the broader goals of the LWRS project in demonstrating the use and safety of the advanced instrumentation and control (I&C) technologies and the short-term and longer term objectives of the plant. In this paper, we review approaches for and human factors issues behind upgrading alarms in the main control room of nuclear power plants.

  4. Application of a spatial modal kinetic model for determination of control rod worths

    International Nuclear Information System (INIS)

    Gomez, A.; Waldman, R.M.

    1993-01-01

    A high-precision rod drop method based on a modal kinetic model, with low dependence on detector location, is proposed to measure the reactivity worth of control rods. This value is obtained from data adjustment for the delayed evolution. It is necessary to maintain the experimental data fluctuation in a small value so that the error of the control rod worth should not be large. A model was developed in order to relate the fluctuation with some parameters which may be modified in the measuring process. The method was applied in the RA-6 reactor to measure control rod worth. For practical purpose it was found that the method can be applied to 15 dollars and it does not depend on relative detector and control rod locations, as the method based on the Point Reactor Model does. (author). 2 refs

  5. Optimum Aggregation and Control of Spatially Distributed Flexible Resources in Smart Grid

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Mendaza, Iker Diaz de Cerio; Myers, Kurt S.

    2018-01-01

    system operators (DSOs) to make faster operational decisions. Moreover, the aggregation enables flexibility from small distributed flexible resources to be traded to different power and energy markets. A hierarchical control architecture comprising a combination of centralized and decentralized control...... is demonstrated through simulation of three operational scenarios in a real low voltage distribution system having high penetrations of electric vehicles and heat pumps. The simulation results demonstrated that the aggregation helps DSOs not only in taking faster operational decisions, but also in effectively...

  6. Factors controlling the spatial distribution of soil piping erosion on loess-derived soils: A case study from central Belgium

    Science.gov (United States)

    Verachtert, E.; Van Den Eeckhaut, M.; Poesen, J.; Deckers, J.

    2010-06-01

    Collapsible loess-derived soils are prone to soil piping erosion, where enlargement of macropores may lead to a subsurface pipe network and eventually to soil collapse and gully development. This study aims at understanding the main factors controlling spatial patterns of piping in loess-derived soils under a temperate climate. To map the spatial distribution of piping and identify the environmental controls on its distribution, a regional survey was carried out in a 236 km 2 study area in the Flemish Ardennes (Belgium). Orthophotos taken at optimal field conditions (winter) were analyzed to detect piping in open landscapes and ground thruthing was systematically done through field surveys. In total, 137 parcels having 560 collapsed pipes were mapped. Dimensions of the sinkholes and local slope gradient were measured in the field and topographical variables were derived from LiDAR data. Land use plays an important role as 97% of the sites with piping are found under pasture. The probability of piping increases rapidly on hillslopes with gradients exceeding 8% and with a concave profile and plan curvature, enhancing subsurface flow concentration. The zones with soil profiles on shallow loess over a relatively thin layer of homogeneous blue massive clays (Aalbeke Member) are most prone to piping. Soil characteristics are of less importance to explain piping occurrence. Furthermore, the topographical threshold line indicating the critical slope gradient for a given contributing drainage area was determined. This threshold line (negative power relation) is similar to the threshold line for shallow gully initiation.

  7. Environmental controls on spatial variability of summer phytoplankton structure and biomass in the Bering Sea

    Science.gov (United States)

    Wang, Yu; Xiang, Peng; Kang, Jian-hua; Ye, You-yin; Lin, Geng-ming; Yang, Qing-liang; Lin, Mao

    2018-01-01

    The subarctic Bering Sea, one of the most productive regions of the world's oceans, is undergoing significant ecological shifts possibly linked to global climate change. During the Fourth Chinese National Arctic Research Expedition (CHINARE) from July 10 to 20 of 2010, phytoplankton community structure, species diversity, spatial distribution, community types, abundance and biomass variations were investigated in a large scale study extending from the Bering Strait into the open waters down to the subarctic Pacific. These patterns were linked to potential environmental drivers, including effects of water masses and seasonal sea ice retreat. Results showed a marked spatial zonation in the taxonomic composition, abundance and biomass. A total of 149 phytoplankton taxa distributed among 57 genera of 5 phyla were identified, characterized into three ecological groups, namely Arctic, Boreal-temperate and cosmopolitan species. Phytoplankton included 101 species of diatoms, 44 species of dinoflagellates, 2 species of Chrysophyta, 1 species of each Chlorophyta and Euglenophyta. Both abundance and biomass were highest in the Bering Shelf, moderate on the Bering Slope, and lowest on the Bering Basin. Chlorophyll a was found highest in the subsurface chlorophyll maxima (SCM) close to the thermocline and halocline layers but its depth varied regionally. Multi-dimensional scaling (MDS) revealed two types of assemblages, one a deep-sea assemblage associated with the Bering Basin and a neritic assemblage found in the Bering Slope and Shelf. Average abundance (10.22 × 103 cells/L), biomass (0.43 mg/m3), species diversity (2.60) and species richness (1.66) were established for deep-sea assemblage with the dominant species ranked as Neodenticula seminae, Chaetoceros atlanticus, Pseudonitzschia delicatissima, and Thalassionema nitzschioides. Neritic assemblage had higher values with 12.73 × 103 cells/L, 2.41 mg/m3, and 2.55 species richness but lower (2.41) species diversity, and

  8. Controllable Spatial Configuration on Cathode Interface for Enhanced Photovoltaic Performance and Device Stability.

    Science.gov (United States)

    Li, Jiangsheng; Duan, Chenghao; Wang, Ning; Zhao, Chengjie; Han, Wei; Jiang, Li; Wang, Jizheng; Zhao, Yingjie; Huang, Changshui; Jiu, Tonggang

    2018-05-08

    The molecular structure of cathode interface modification materials can affect the surface morphology of the active layer and key electron transfer processes occurring at the interface of polymer solar cells in inverted structures mostly due to the change of molecular configuration. To investigate the effects of spatial configuration of the cathode interfacial modification layer on polymer solar cells device performances, we introduced two novel organic ionic salts (linear NS2 and three-dimensional (3D) NS4) combined with the ZnO film to fabricate highly efficient inverted solar cells. Both organic ionic salts successfully decreased the surface traps of the ZnO film and made its work function more compatible. Especially NS4 in three-dimensional configuration increased the electron mobility and extraction efficiency of the interfacial film, leading to a significant improvement of device performance. Power conversion efficiency (PCE) of 10.09% based on NS4 was achieved. Moreover, 3D interfacial modification could retain about 92% of its initial PCE over 160 days. It is proposed that 3D interfacial modification retards the element penetration-induced degradation without impeding the electron transfer from the active layer to the ZnO film, which significantly improves device stability. This indicates that inserting three-dimensional organic ionic salt is an efficient strategy to enhance device performance.

  9. Spatial interpretation of NASA's Marshall Space Flight Center Payload Operations Control Center using virtual reality technology

    Science.gov (United States)

    Lindsey, Patricia F.

    1993-01-01

    In its search for higher level computer interfaces and more realistic electronic simulations for measurement and spatial analysis in human factors design, NASA at MSFC is evaluating the functionality of virtual reality (VR) technology. Virtual reality simulation generates a three dimensional environment in which the participant appears to be enveloped. It is a type of interactive simulation in which humans are not only involved, but included. Virtual reality technology is still in the experimental phase, but it appears to be the next logical step after computer aided three-dimensional animation in transferring the viewer from a passive to an active role in experiencing and evaluating an environment. There is great potential for using this new technology when designing environments for more successful interaction, both with the environment and with another participant in a remote location. At the University of North Carolina, a VR simulation of a the planned Sitterson Hall, revealed a flaw in the building's design that had not been observed during examination of the more traditional building plan simulation methods on paper and on computer aided design (CAD) work station. The virtual environment enables multiple participants in remote locations to come together and interact with one another and with the environment. Each participant is capable of seeing herself and the other participants and of interacting with them within the simulated environment.

  10. A Spatial Control for Correct Timing of Gene Expression during the Escherichia coli Cell Cycle

    Directory of Open Access Journals (Sweden)

    Yuan Yao

    2016-12-01

    Full Text Available Temporal transcriptions of genes are achieved by different mechanisms such as dynamic interaction of activator and repressor proteins with promoters, and accumulation and/or degradation of key regulators as a function of cell cycle. We find that the TorR protein localizes to the old poles of the Escherichia coli cells, forming a functional focus. The TorR focus co-localizes with the nucleoid in a cell-cycle-dependent manner, and consequently regulates transcription of a number of genes. Formation of one TorR focus at the old poles of cells requires interaction with the MreB and DnaK proteins, and ATP, suggesting that TorR delivery requires cytoskeleton organization and ATP. Further, absence of the protein–protein interactions and ATP leads to loss in function of TorR as a transcription factor. We propose a mechanism for timing of cell-cycle-dependent gene transcription, where a transcription factor interacts with its target genes during a specific period of the cell cycle by limiting its own spatial distribution.

  11. Auditory perception and the control of spatially coordinated action of deaf and hearing children.

    Science.gov (United States)

    Savelsbergh, G J; Netelenbos, J B; Whiting, H T

    1991-03-01

    From birth onwards, auditory stimulation directs and intensifies visual orientation behaviour. In deaf children, by definition, auditory perception cannot take place and cannot, therefore, make a contribution to visual orientation to objects approaching from outside the initial field of view. In experiment 1, a difference in catching ability is demonstrated between deaf and hearing children (10-13 years of age) when the ball approached from the periphery or from outside the field of view. No differences in catching ability between the two groups occurred when the ball approached from within the field of view. A second experiment was conducted in order to determine if differences in catching ability between deaf and hearing children could be attributed to execution of slow orientating movements and/or slow reaction time as a result of the auditory loss. The deaf children showed slower reaction times. No differences were found in movement times between deaf and hearing children. Overall, the findings suggest that a lack of auditory stimulation during development can lead to deficiencies in the coordination of actions such as catching which are both spatially and temporally constrained.

  12. Control of cell division and the spatial localization of assembled gene products in Caulobacter crescentus

    International Nuclear Information System (INIS)

    Nathan, P.D.

    1988-01-01

    Experiments are described that examine the role of penicillin-binding proteins (PBPs) in the regulation of cell division in Caulobacter crescentus; and the spatial localization of methyl-accepting chemotaxis proteins (MCPs) in C. crescentus swarmer and predivisional cells. In the analysis of PBP function, in vivo and in vitro assays are used to directly label C. crescentus PBPs with [ 3 H] penicillin G in wild type strain CB15, in a series of conditional cell division mutants and in new temperature sensitive cephalosporin C resistant mutants PC8002 and PC8003. 14 PBPs are characterized and a high molecular weight PBP (PBP 1B) that is required for cell division is identified. PBP 1B competes for β-lactams that induce filament formation and may be a high affinity binding protein. A second high molecular weight PBP (PBP 1C) is also associated with defective cell division. The examination of PBP patterns in synchronous swarmer cells reveals that the in vivo activity of PBP 1B and PBP 1C increases at the time that the cell division pathway is initiated. None of the PBPs, however, appear to be differentially localized in the C. crescentus cell. In the analysis of MCP localization, in vivo and in vitro assays are used to directly label C. crescentus MCPs with methyl- 3 H. MCPs are examined in flagellated and non-flagellated vesicles prepared from cells by immunoaffinity chromatography

  13. Spatially resolved metabolic analysis reveals a central role for transcriptional control in carbon allocation to wood.

    Science.gov (United States)

    Roach, Melissa; Arrivault, Stéphanie; Mahboubi, Amir; Krohn, Nicole; Sulpice, Ronan; Stitt, Mark; Niittylä, Totte

    2017-06-15

    The contribution of transcriptional and post-transcriptional regulation to modifying carbon allocation to developing wood of trees is not well defined. To clarify the role of transcriptional regulation, the enzyme activity patterns of eight central primary metabolism enzymes across phloem, cambium, and developing wood of aspen (Populus tremula L.) were compared with transcript levels obtained by RNA sequencing of sequential stem sections from the same trees. Enzymes were selected on the basis of their importance in sugar metabolism and in linking primary metabolism to lignin biosynthesis. Existing enzyme assays were adapted to allow measurements from ~1 mm3 sections of dissected stem tissue. These experiments provided high spatial resolution of enzyme activity changes across different stages of wood development, and identified the gene transcripts probably responsible for these changes. In most cases, there was a clear positive relationship between transcripts and enzyme activity. During secondary cell wall formation, the increases in transcript levels and enzyme activities also matched with increased levels of glucose, fructose, hexose phosphates, and UDP-glucose, emphasizing an important role for transcriptional regulation in carbon allocation to developing aspen wood. These observations corroborate the efforts to increase carbon allocation to wood by engineering gene regulatory networks. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  14. Enhanced odor discrimination and impaired olfactory memory by spatially controlled switch of AMPA receptors.

    Directory of Open Access Journals (Sweden)

    Derya R Shimshek

    2005-11-01

    Full Text Available Genetic perturbations of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs are widely used to dissect molecular mechanisms of sensory coding, learning, and memory. In this study, we investigated the role of Ca2+-permeable AMPARs in olfactory behavior. AMPAR modification was obtained by depletion of the GluR-B subunit or expression of unedited GluR-B(Q, both leading to increased Ca2+ permeability of AMPARs. Mice with this functional AMPAR switch, specifically in forebrain, showed enhanced olfactory discrimination and more rapid learning in a go/no-go operant conditioning task. Olfactory memory, however, was dramatically impaired. GluR-B depletion in forebrain was ectopically variable ("mosaic" among individuals and strongly correlated with decreased olfactory memory in hippocampus and cortex. Accordingly, memory was rescued by transgenic GluR-B expression restricted to piriform cortex and hippocampus, while enhanced odor discrimination was independent of both GluR-B variability and transgenic GluR-B expression. Thus, correlated differences in behavior and levels of GluR-B expression allowed a mechanistic and spatial dissection of olfactory learning, discrimination, and memory capabilities.

  15. Enhanced odor discrimination and impaired olfactory memory by spatially controlled switch of AMPA receptors.

    Science.gov (United States)

    Shimshek, Derya R; Bus, Thorsten; Kim, Jinhyun; Mihaljevic, Andre; Mack, Volker; Seeburg, Peter H; Sprengel, Rolf; Schaefer, Andreas T

    2005-11-01

    Genetic perturbations of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) are widely used to dissect molecular mechanisms of sensory coding, learning, and memory. In this study, we investigated the role of Ca2+-permeable AMPARs in olfactory behavior. AMPAR modification was obtained by depletion of the GluR-B subunit or expression of unedited GluR-B(Q), both leading to increased Ca2+ permeability of AMPARs. Mice with this functional AMPAR switch, specifically in forebrain, showed enhanced olfactory discrimination and more rapid learning in a go/no-go operant conditioning task. Olfactory memory, however, was dramatically impaired. GluR-B depletion in forebrain was ectopically variable ("mosaic") among individuals and strongly correlated with decreased olfactory memory in hippocampus and cortex. Accordingly, memory was rescued by transgenic GluR-B expression restricted to piriform cortex and hippocampus, while enhanced odor discrimination was independent of both GluR-B variability and transgenic GluR-B expression. Thus, correlated differences in behavior and levels of GluR-B expression allowed a mechanistic and spatial dissection of olfactory learning, discrimination, and memory capabilities.

  16. Micro-spatial distribution of malaria cases and control strategies at ward level in Gwanda district, Matabeleland South, Zimbabwe.

    Science.gov (United States)

    Manyangadze, Tawanda; Chimbari, Moses J; Macherera, Margaret; Mukaratirwa, Samson

    2017-11-21

    Although there has been a decline in the number of malaria cases in Zimbabwe since 2010, the disease remains the biggest public health threat in the country. Gwanda district, located in Matabeleland South Province of Zimbabwe has progressed to the malaria pre-elimination phase. The aim of this study was to determine the spatial distribution of malaria incidence at ward level for improving the planning and implementation of malaria elimination in the district. The Poisson purely spatial model was used to detect malaria clusters and their properties, including relative risk and significance levels at ward level. The geographically weighted Poisson regression (GWPR) model was used to explore the potential role and significance of environmental variables [rainfall, minimum and maximum temperature, altitude, Enhanced Vegetation Index (EVI), Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), rural/urban] and malaria control strategies [indoor residual spraying (IRS) and long-lasting insecticide-treated nets (LLINs)] on the spatial patterns of malaria incidence at ward level. Two significant clusters (p malaria cases were identified: (1) ward 24 south of Gwanda district and (2) ward 9 in the urban municipality, with relative risks of 5.583 and 4.316, respectively. The semiparametric-GWPR model with both local and global variables had higher performance based on AICc (70.882) compared to global regression (74.390) and GWPR which assumed that all variables varied locally (73.364). The semiparametric-GWPR captured the spatially non-stationary relationship between malaria cases and minimum temperature, NDVI, NDWI, and altitude at the ward level. The influence of LLINs, IRS and rural or urban did not vary and remained in the model as global terms. NDWI (positive coefficients) and NDVI (range from negative to positive coefficients) showed significant association with malaria cases in some of the wards. The IRS had a protection effect on

  17. Digital control of laser modes with an intra-cavity spatial light modulator

    CSIR Research Space (South Africa)

    Ngcobo, S

    2014-02-01

    Full Text Available addressed holographic end-mirror. We show that on-demand digitally controlled laser modes are possible by changing the phase and amplitude of the computer generated hologram in a form of a grey-scale image on the holographic mirror. We demonstrate...

  18. In vitro parameter optimization for spatial control of focused ultrasound ablation when using low boiling point phase-change nanoemulsions.

    Science.gov (United States)

    Puett, Connor; Phillips, Linsey C; Sheeran, Paul S; Dayton, Paul A

    2013-01-01

    Phase-shift nanoemulsions (PSNEs) provide cavitation sites when the perfluorocarbon (PFC) nanodroplets (ND) are vaporized to microbubbles by acoustic energy. Their presence lowers the power required to ablate tissue by high-intensity focused ultrasound (HIFU), potentially making it a safer option for a broader range of treatment sites. However, spatial control over the ablation region can be problematic when cavitation is used to enhance heating. This study explored relationships between vaporization, ablation, and the PSNE concentration in vitro to optimize the acoustic intensity and insonation time required for spatially controlled ablation enhancement using a PSNE that included a volatile PFC component. HIFU (continuous wave at 1 MHz; insonation times of 5, 10, 15, and 20 s; cool-down times of 2, 4, and 6 s; peak negative pressures of 2, 3, and 4 MPa) was applied to albumin-acrylamide gels containing PFC agents (1:1 mix of volatile decafluorobutane and more stable dodecafluoropentane at 10(5) to 10(8) PFC ND per milliliter) or agent-free controls. Vaporization fields (microbubble clouds) were imaged by conventional ultrasound, and ablation lesions were measured directly by calipers. Controlled ablation was defined as the production of 'cigar'-shaped lesions corresponding with the acoustic focal zone. This control was considered to be lost when ablation occurred in prefocal vaporization fields having a predominantly 'tadpole' or oblong shape. Changes in the vaporization field shape and location occurred on a continuum with increasing PSNE concentration and acoustic intensity. Working with the maximum concentration-intensity combinations resulting in controlled ablation demonstrated a dose-responsive relationship between insonation time and volumes of both the vaporization fields (approximately 20 to 240 mm(3)) and the ablation lesions (1 to 135 mm(3)) within them. HIFU ablation was enhanced by this PSNE and could be achieved using intensities ≤650 W/cm(2

  19. Separation system

    International Nuclear Information System (INIS)

    Rubin, L.S.

    1986-01-01

    A disposal container is described for use in disposal of radioactive waste materials consisting of: top wall structure, bottom wall structure, and circumferential side wall structure interconnecting the top and bottom wall structures to define an enclosed container, separation structure in the container adjacent the inner surface of the side wall structure for allowing passage of liquid and retention of solids, inlet port structure in the top wall structure, discharge port structure at the periphery of the container in communication with the outer surface of the separation structure for receiving liquid that passes through the separation structure, first centrifugally actuated valve structure having a normal position closing the inlet port structure and a centrifugally actuated position opening the inlet port structure, second centrifugally actuated valve structure having a normal position closing the discharge port structure and a centrifugally actuated position opening the discharge port structure, and coupling structure integral with wall structure of the container for releasable engagement with centrifugal drive structure

  20. Separable algebras

    CERN Document Server

    Ford, Timothy J

    2017-01-01

    This book presents a comprehensive introduction to the theory of separable algebras over commutative rings. After a thorough introduction to the general theory, the fundamental roles played by separable algebras are explored. For example, Azumaya algebras, the henselization of local rings, and Galois theory are rigorously introduced and treated. Interwoven throughout these applications is the important notion of étale algebras. Essential connections are drawn between the theory of separable algebras and Morita theory, the theory of faithfully flat descent, cohomology, derivations, differentials, reflexive lattices, maximal orders, and class groups. The text is accessible to graduate students who have finished a first course in algebra, and it includes necessary foundational material, useful exercises, and many nontrivial examples.

  1. Spatial econometrics using microdata

    CERN Document Server

    Dubé, Jean

    2014-01-01

    This book provides an introduction to spatial analyses concerning disaggregated (or micro) spatial data.Particular emphasis is put on spatial data compilation and the structuring of the connections between the observations. Descriptive analysis methods of spatial data are presented in order to identify and measure the spatial, global and local dependency.The authors then focus on autoregressive spatial models, to control the problem of spatial dependency between the residues of a basic linear statistical model, thereby contravening one of the basic hypotheses of the ordinary least squares appr

  2. Isotope separation

    International Nuclear Information System (INIS)

    Bartlett, R.J.; Morrey, J.R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated

  3. From brain synapses to systems for learning and memory: Object recognition, spatial navigation, timed conditioning, and movement control.

    Science.gov (United States)

    Grossberg, Stephen

    2015-09-24

    This article provides an overview of neural models of synaptic learning and memory whose expression in adaptive behavior depends critically on the circuits and systems in which the synapses are embedded. It reviews Adaptive Resonance Theory, or ART, models that use excitatory matching and match-based learning to achieve fast category learning and whose learned memories are dynamically stabilized by top-down expectations, attentional focusing, and memory search. ART clarifies mechanistic relationships between consciousness, learning, expectation, attention, resonance, and synchrony. ART models are embedded in ARTSCAN architectures that unify processes of invariant object category learning, recognition, spatial and object attention, predictive remapping, and eye movement search, and that clarify how conscious object vision and recognition may fail during perceptual crowding and parietal neglect. The generality of learned categories depends upon a vigilance process that is regulated by acetylcholine via the nucleus basalis. Vigilance can get stuck at too high or too low values, thereby causing learning problems in autism and medial temporal amnesia. Similar synaptic learning laws support qualitatively different behaviors: Invariant object category learning in the inferotemporal cortex; learning of grid cells and place cells in the entorhinal and hippocampal cortices during spatial navigation; and learning of time cells in the entorhinal-hippocampal system during adaptively timed conditioning, including trace conditioning. Spatial and temporal processes through the medial and lateral entorhinal-hippocampal system seem to be carried out with homologous circuit designs. Variations of a shared laminar neocortical circuit design have modeled 3D vision, speech perception, and cognitive working memory and learning. A complementary kind of inhibitory matching and mismatch learning controls movement. This article is part of a Special Issue entitled SI: Brain and Memory

  4. On separable Pauli equations

    International Nuclear Information System (INIS)

    Zhalij, Alexander

    2002-01-01

    We classify (1+3)-dimensional Pauli equations for a spin-(1/2) particle interacting with the electro-magnetic field, that are solvable by the method of separation of variables. As a result, we obtain the 11 classes of vector-potentials of the electro-magnetic field A(t,x(vector sign))=(A 0 (t,x(vector sign)), A(vector sign)(t,x(vector sign))) providing separability of the corresponding Pauli equations. It is established, in particular, that the necessary condition for the Pauli equation to be separable into second-order matrix ordinary differential equations is its equivalence to the system of two uncoupled Schroedinger equations. In addition, the magnetic field has to be independent of spatial variables. We prove that coordinate systems and the vector-potentials of the electro-magnetic field providing the separability of the corresponding Pauli equations coincide with those for the Schroedinger equations. Furthermore, an efficient algorithm for constructing all coordinate systems providing the separability of Pauli equation with a fixed vector-potential of the electro-magnetic field is developed. Finally, we describe all vector-potentials A(t,x(vector sign)) that (a) provide the separability of Pauli equation, (b) satisfy vacuum Maxwell equations without currents, and (c) describe non-zero magnetic field

  5. The spatially global control of attentional target selection in visual search

    OpenAIRE

    Berggren, Nick; Jenkins, M.; McCants, C.W.; Eimer, Martin

    2017-01-01

    Glyn Humphreys and his co-workers have made numerous important theoretical and empirical contributions to research on visual search. They have introduced the concept of attentional target templates and investigated the nature of these templates and how they are involved in the control of search performance. In the experiments reported here, we investigated whether feature-specific search template for particular colours can guide target selection independently for different regions of visual s...

  6. Recycling isoelectric focusing with computer controlled data acquisition system. [for high resolution electrophoretic separation and purification of biomolecules

    Science.gov (United States)

    Egen, N. B.; Twitty, G. E.; Bier, M.

    1979-01-01

    Isoelectric focusing is a high-resolution technique for separating and purifying large peptides, proteins, and other biomolecules. The apparatus described in the present paper constitutes a new approach to fluid stabilization and increased throughput. Stabilization is achieved by flowing the process fluid uniformly through an array of closely spaced filter elements oriented parallel both to the electrodes and the direction of the flow. This seems to overcome the major difficulties of parabolic flow and electroosmosis at the walls, while limiting the convection to chamber compartments defined by adjacent spacers. Increased throughput is achieved by recirculating the process fluid through external heat exchange reservoirs, where the Joule heat is dissipated.

  7. Spatial and temporal controls of atoll island inundation: implications for urbanized atolls in the Marshall Islands.

    Science.gov (United States)

    Ford, M.; Becker, J. M.; Merrifield, M. A.

    2012-12-01

    Atoll islands are highly vulnerable to a range of inundation hazards. The impacts of such hazards are expected to be magnified as a result of continued sea-level rise. Both recent and historic inundation events provide unique insights into the requisite conditions necessary to initiate island inundation. A number of recent and historic inundation events are presented in order to examine the oceanographic and meteorological conditions driving inundation of a densely populated, urbanized atoll in the central Pacific. Analysis of inundation events suggests that a number of key drivers contribute to the spatial and temporal extent of island inundation, with unique degrees of predictability and resultant impact signatures apparent on island geomorphology and local anthropogenic activities. Results indicate three distinct drivers of inundation hazards exist. Firstly, tropical storms and typhoons elevate sea level through inverse barometric setup, wind setup and a range of wave driven processes and have caused considerable impact on atolls within the Marshall Islands. Secondly, super-elevated sea level conditions resulting from the combination of seasonal high tides and quasi-cyclical La Nina conditions drive inundation of low-lying lagoon facing coastal areas. Thirdly, long period swell conditions, typically generated by distant storms, can elevate reef-flat water levels through wave setup and infragravity wave oscillations. Such wave conditions can over wash the ocean-facing island ridge, often inundating large sections of the island. Reef-flat wave conditions are tidally modulated, with inundation events typically occurring around high tide. However, the two most recent destructive swell-driven inundation events have occurred while tide levels were significantly lower than spring tide levels, suggesting high water levels are not a necessary prerequisite for wave-driven inundation. The different modes of inundation are discussed and grounded within recent and historic

  8. Empirical Modeling of Spatial 3D Flow Characteristics Using a Remote-Controlled ADCP System: Monitoring a Spring Flood

    Directory of Open Access Journals (Sweden)

    Claude Flener

    2015-01-01

    Full Text Available The use of acoustic Doppler current profilers (ADCP for measuring streamflow and discharge is becoming increasingly widespread. The spatial distribution of flow patterns is useful data in studying riverine habitats and geomorphology. Until now, most flow mapping has focused on measurements along a series of transects in a channel. Here, we set out to measure, model and analyze the 3D flow characteristics of a natural river over a continuous areal extent, quantifying flow velocity, 3D flow directions, volumes, water depth and their changes over time. We achieved multidimensional spatial flow measurements by deploying an ADCP on a remotely-controlled boat, combined with kinematic GNSS positioning and locally-monitored water level data. We processed this data into a 3D point cloud of accurately positioned individual 3D flow measurements that allows the visual analysis of flow velocities, directions and channel morphology in 3D space. We demonstrate how this allows monitoring changes of flow patterns with a time series of flow point clouds measured over the period of a spring flood in Finnish Lapland. Furthermore, interpolating the raw point cloud onto a 3D matrix allows us to quantify volumetric flow while reducing noise in the data. We can now quantify the volumes of water moving at certain velocities in a given reach and their location in 3D space, allowing, for instance, the monitoring of the high-velocity core and its changes over time.

  9. MASTR: A Technique for Mosaic Mutant Analysis with Spatial and Temporal Control of Recombination Using Conditional Floxed Alleles in Mice

    Directory of Open Access Journals (Sweden)

    Zhimin Lao

    2012-08-01

    Full Text Available Mosaic mutant analysis, the study of cellular defects in scattered mutant cells in a wild-type environment, is a powerful approach for identifying critical functions of genes and has been applied extensively to invertebrate model organisms. A highly versatile technique has been developed in mouse: MASTR (mosaic mutant analysis with spatial and temporal control of recombination, which utilizes the increasing number of floxed alleles and simultaneously combines conditional gene mutagenesis and cell marking for fate analysis. A targeted allele (R26MASTR was engineered; the allele expresses a GFPcre fusion protein following FLP-mediated recombination, which serves the dual function of deleting floxed alleles and marking mutant cells with GFP. Within 24 hr of tamoxifen administration to R26MASTR mice carrying an inducible FlpoER transgene and a floxed allele, nearly all GFP-expressing cells have a mutant allele. The fate of single cells lacking FGF8 or SHH signaling in the developing hindbrain was analyzed using MASTR, and it was revealed that there is only a short time window when neural progenitors require FGFR1 for viability and that granule cell precursors differentiate rapidly when SMO is lost. MASTR is a powerful tool that provides cell-type-specific (spatial and temporal marking of mosaic mutant cells and is broadly applicable to developmental, cancer, and adult stem cell studies.

  10. Separate development of the maxilla and mandible is controlled by regional signaling of the maxillomandibular junction during avian development.

    Science.gov (United States)

    Tak, Hye-Jin; Park, Tae-Jin; Piao, Zhenngu; Lee, Sang-Hwy

    2017-01-01

    Syngnathia is a congenital craniofacial disorder characterized by bony or soft tissue fusion of upper and lower jaws. Previous studies suggested some causative signals, such as Foxc1 or Bmp4, cause the disruption of maxillomandibular identity, but their location and the interactive signals involved remain unexplored. We wanted to examine the embryonic origin of syngnathia based on the assumption that it may be located at the separation between the maxillary and mandibular processes. This region, known as the maxillomandibular junction (MMJ), is involved in segregation of cranial neural crest-derived mesenchyme into the presumptive upper and lower jaws. Here we investigated the role of Fgf, Bmp, and retinoid signaling during development of MMJ in chicken embryos. By changing the levels of these signals with bead implants, we induced syngnathia with microstomia on the treated side, which showed increased Barx1 and neural cell adhesion molecule (NCAM) expression. Redistribution of proliferating cells was also observed at the proximal region to maxillary and mandibular arch around MMJ. We propose that interactive molecular signaling by Fgfs, Bmps, and retinoids around MMJ is required for normal separation of the maxilla and mandible, as well as the proper positioning of beak commissure during early facial morphogenesis. Developmental Dynamics 246:28-40, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Ketogenic diet does not impair spatial ability controlled by the hippocampus in male rats.

    Science.gov (United States)

    Fukushima, Atsushi; Ogura, Yuji; Furuta, Miyako; Kakehashi, Chiaki; Funabashi, Toshiya; Akema, Tatsuo

    2015-10-05

    A ketogenic diet was recently shown to reduce glutamate accumulation in synaptic vesicles, decreasing glutamate transmission. We questioned whether a ketogenic diet affects hippocampal function, as glutamate transmission is critically involved in visuospatial ability. In the present study, male Wistar rats were maintained on a ketogenic diet containing 10% protein and 90% fat with complements for 3 weeks to change their energy expenditure from glucose-dependent to fat-dependent. Control rats were fed a diet containing 10% protein, 10% fat, and 80% carbohydrates. The fat-dependent energy expenditure induced by the ketogenic diet led to decreased body weight and increased blood ketone production, though the rats in the two groups consumed the same number of calories. The ketogenic diet did not alter food preferences for the control or high-fat diet containing 10% protein, 45% fat, and 45% carbohydrates. Anxiety in the open field was not altered by ingestion the ketogenic diet. However, rats fed the ketogenic diet performed better in the Y-maze test than rats fed the control diet. No difference was observed between the two groups in the Morris water maze test. Finally, Western blot revealed that the hippocampal expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor subunit 1 (GluR1) was significantly increased in mice fed a ketogenic diet. These results suggest that hippocampal function is not impaired by a ketogenic diet and we speculate that the fat-dependent energy expenditure does not impair visuospatial ability. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Spatial variation in microbial processes controlling carbon mineralization within soils and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fendorf, Scott [Stanford Univ., CA (United States); Kleber, Markus [Oregon State Univ., Corvallis, OR (United States); Nico, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-10-19

    Soils have a defining role in global carbon cycling, having one of the largest dynamic stocks of C on earth—3300 Pg of C are stored in soils, which is three-times the amount stored in the atmosphere and more than the terrestrial land plants. An important control on soil organic matter (SOM) quantities is the mineralization rate. It is well recognized that the rate and extent of SOM mineralization is affected by climatic factors and mineral-organic matter associations. What remained elusive is to what extent constraints on microbial metabolism induced by the respiratory pathway, and specifically the electron acceptor in respiration, control overall rates of carbon mineralization in soils. Therefore, physical factors limiting oxygen diffusion such as soil texture and aggregate size (soil structure) may therefore be central controls on C mineralization rates. The goal of our research was therefore to determine if variations in microbial metabolic rates induced by anaerobic microsites in soils are a major control on SOM mineralization rates and thus storage. We performed a combination of laboratory experiments and field investigations will be performed to fulfill our research objectives. We used laboratory studies to examine fundamental factors of respiratory constraints (i.e., electron acceptor) on organic matter mineralization rates. We ground our laboratory studies with both manipulation of field samples and in-field measurements. Selection of the field sites is guided by variation in soil texture and structure while having (other environmental/soil factors constant. Our laboratory studies defined redox gradients and variations in microbial metabolism operating at the aggregate-scale (cm-scale) within soils using a novel constructed diffusion reactor. We further examined micro-scale variation in terminal electron accepting processes and resulting C mineralization rates within re-packed soils. A major outcome of our research is the ability to quantitatively place

  13. Combining observations of channel network contraction and spatial discharge variation to inform spatial controls on baseflow in Birch Creek, Catskill Mountains, USA

    Directory of Open Access Journals (Sweden)

    Stephen B. Shaw

    2017-08-01

    New hydrological insights: For the 31 different sub-channels, baseflow discharge per unit drainage area and per unit stream length were highly variable, even during periods of higher moisture storage when all channels were active. Simple mapping of the active channels would not have recognized these sizable spatial differences in discharge contribution. Previous studies of hydrologic scaling in the Catskills have noted the likelihood of heterogeneity in discharge below a threshold of approximately 3–8 km2. This study provides direct documentation of such heterogeneity at smaller spatial scales. When considering perennial and ephemeral streams, such heterogeneity was not well explained by standard topographic, geologic, or meteorological factors. We suggest the heterogeneity may arise from difficult to map fine-scale variations in subsurface properties.

  14. Spatially Controlled Delivery of siRNAs to Stem Cells in Implants Generated by Multi-Component Additive Manufacturing

    DEFF Research Database (Denmark)

    Andersen, Morten Østergaard; Le, Dang Quang Svend; Chen, Muwan

    2013-01-01

    Additive manufacturing is a promising technique in tissue engineering, as it enables truly individualized implants to be made to fit a particular defect. As previously shown, a feasible strategy to produce complex multicellular tissues is to deposit different small interfering RNA (siRNA) in porous...... implants that are subsequently sutured together. In this study, an additive manufacturing strategy to deposit carbohydrate hydrogels containing different siRNAs is applied into an implant, in a spatially controlled manner. When the obtained structures are seeded with mesenchymal stem (stromal) cells......, the selected siRNAs are delivered to the cells and induces specific and localized gene silencing. Here, it is demonstrated how to replicate part of a patient's spinal cord from a computed tomography scan, using an additive manufacturing technique to produce an implant with compartmentalized si...

  15. From nano- to macro-scale: nanotechnology approaches for spatially controlled delivery of bioactive factors for bone and cartilage engineering.

    Science.gov (United States)

    Santo, Vítor E; Gomes, Manuela E; Mano, João F; Reis, Rui L

    2012-07-01

    The field of biomaterials has advanced towards the molecular and nanoscale design of bioactive systems for tissue engineering, regenerative medicine and drug delivery. Spatial cues are displayed in the 3D extracellular matrix and can include signaling gradients, such as those observed during chemotaxis. Architectures range from the nanometer to the centimeter length scales as exemplified by extracellular matrix fibers, cells and macroscopic shapes. The main focus of this review is the application of a biomimetic approach by the combination of architectural cues, obtained through the application of micro- and nanofabrication techniques, with the ability to sequester and release growth factors and other bioactive agents in a spatiotemporal controlled manner for bone and cartilage engineering.

  16. A biomimetic physiological model for human adipose tissue by adipocytes and endothelial cell cocultures with spatially controlled distribution

    International Nuclear Information System (INIS)

    Yao, Rui; Zhang, Renji; Lin, Feng; Du, Yanan; Luan, Jie

    2013-01-01

    An in vitro model that recapitulates the characteristics of native human adipose tissue would largely benefit pathology studies and therapy development. In this paper, we fabricated a physiological model composed of both human adipocytes and endothelial cells with spatially controlled distribution that biomimics the structure and composition of human adipose tissue. Detailed studies into the cell–cell interactions between the adipocytes and endothelial cells revealed a mutual-enhanced effect which resembles the in vivo routine. Furthermore, comparisons between planar coculture and model coculture demonstrated improved adipocyte function as well as endothelial cell proliferation under the same conditions. This research provided a reliable model for human adipose tissue development studies and potential obesity-related therapy development. (paper)

  17. Preparation of novel cotton fabric composites with pH controlled switchable wettability for efficient water-in-oil and oil-in-water emulsions separation

    Science.gov (United States)

    Wang, Qian; Wu, Jianning; Meng, Guihua; Wang, Yixi; Liu, Zhiyong; Guo, Xuhong

    2018-06-01

    The wetting materials with the ability of controllable oil/water separation have drawn more and more public attention. In this article, the novel cotton fabric (CF) with pH controlled wettability transition was designed by a simple, environmentally friendly coating copolymer/SiO2 nanoparticles, poly(heptadecafluorodecyl methacrylate- co-3-trimethoxysilylpropyl methacrylate- co-2-vinilpiridine) (PHDFDMA- co-PTMSPMA- co-P2VP). Furthermore, the structures and morphologies of coated CF were confirmed by Fourier transform infrared spectroscopy (FTIR), NMR, GPC, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The coated CF exhibits switchable wettability between superhydrophobicity and superhydrophilicity via adjusting pH value. When the coated CF is placed in the neutral aqueous (pH = 7.0), it is superhydrophobic in the air and superoleophilic. It allows oil to go through but blocking water. However, in acidic aqueous environment (pH = 3.0), it turns superhydrophilic and underwater superoleophobic, which allows water to penetrate but blocking oil. Therefore, the coated CF could be applied to separate oil/water mixtures, ternary oil/water/water mixtures continuously and different surfactant stabilized emulsions (oil-in-water, water-in-oil) and displays the superior separation capacity for oil-water mixtures with a high efficiency of 99.8%. Moreover, the cycling tests demonstrate that the coated CF possesses excellent recyclability and durability. Such an eminent, controllable water/oil permeation feature makes coated CF could be selected as an ideal candidate for oil/water separation.

  18. Predicting family health and well-being after separation from an abusive partner: role of coercive control, mother's depression and social support.

    Science.gov (United States)

    Broughton, Sharon; Ford-Gilboe, Marilyn

    2017-08-01

    Drawing on the Strengthening Capacity to Limit Intrusion theory, we tested whether intrusion (i.e. unwanted interference from coercive control, custody and access difficulties and mother's depressive symptoms) predicted family health and well-being after separation from an abusive partner/father, and whether social support moderated intrusion effects on family health and well-being. Experiences of coercive control and the negative consequences related to those experiences have been documented among women who have separated from an abusive partner. We conducted a secondary analysis of data from 154 adult, Canadian mothers of dependent children who had separated from an abusive partner and who participated in Wave 2 of the Women's Health Effects Study. We used hierarchical multiple regression to test whether intrusion predicts family health and well-being as well as whether social support moderated this relationship. Families were found to experience considerable intrusion, yet their health and well-being was similar to population norms. Intrusion predicted 11·4% of the variance in family health and well-being, with mother's depressive symptoms as the only unique predictor. Social support accounted for an additional 9% of explained variance, but did not buffer intrusion effects on family health and well-being. Although women had been separated from their abusive partners for an average of 2·5 years, the majority continued to experience coercive control. On average, levels of social support and family functioning were relatively high, contrary to public and academic discourse. In working with these families postseparation, nurses should approach care from a strength-based perspective, and integrate tailored assessment and intervention options for women and families that address both depression and social support. © 2016 John Wiley & Sons Ltd.

  19. Spatially explicit simulation of hydrologically controlled carbon and nitrogen cycles and associated feedback mechanisms in a boreal ecosystem

    Science.gov (United States)

    Govind, Ajit; Chen, Jing Ming; Ju, Weimin

    2009-06-01

    Ecosystem models that simulate biogeochemical processes usually ignore hydrological controls that govern them. It is quite possible that topographically driven water fluxes significantly influence the spatial distribution of C sources and sinks because of their large contribution to the local water balance. To investigate this, we simulated biogeochemical processes along with the associated feedback mechanisms in a boreal ecosystem using a spatially explicit hydroecological model, boreal ecosystem productivity simulator (BEPS)-TerrainLab V2.0, that has a tight coupling of ecophysiological, hydrological, and biogeochemical processes. First, the simulated dynamics of snowpack, soil temperature, net ecosystem productivity (NEP), and total ecosystem respiration (TER) were validated with high-frequency measurements for 2 years. The model was able to explain 80% of the variability in NEP and 84% of the variability in TER. Further, we investigated the influence of topographically driven subsurface base flow on soil C and N cycling and on the spatiotemporal patterns of C sources and sinks using three hydrological modeling scenarios that differed in hydrological conceptualizations. In general, the scenarios that had nonexplicit hydrological representation overestimated NEP, as opposed to the scenario that had an explicit (realistic) representation. The key processes controlling the NEP differences were attributed to the combined effects of variations in photosynthesis (due to changes in stomatal conductance and nitrogen (N) availability), heterotrophic respiration, and autotrophic respiration, all of which occur simultaneously affecting NEP. Feedback relationships were also found to exacerbate the differences. We identified six types of NEP differences (biases), of which the most commonly found was due to an underestimation of the existing C sources, highlighting the vulnerability of regional-scale ecosystem models that ignore hydrological processes.

  20. Spatial Control of Photoacid Diffusion in Chemically Amplified Resist (CAR) via External Electric Field.

    Science.gov (United States)

    Kim, Jinok; Yoo, Gwangwe; Park, Jin; Park, Jin-Hong

    2018-09-01

    We investigated the effect of an electric field-based post exposure bake (EF-PEB) process on photoacid diffusion and pattern formation. To investigate the control of photoacid diffusion experimentally, the EF-PEB processes was performed at various temperatures. Cross sectional images of various EF-PEB processed samples were obtained by scanning electron microscopy (SEM) after ion beam milling. In addition, we conducted a numerical analysis of photoacid distribution and diffusion with following Fick's second law and compared the experimental results with our theoretical model. The drift distance was theoretically predicted by multiplying drift velocity and EF-PEB time, and the experimental values were obtained by finding the difference in pattern depths of PEB/EFPEB samples. Finally, an EF-PEB temperature of 85 °C was confirmed as the optimum condition to maximize photoacid drift distance using the electric field.

  1. An internet-based self-help intervention for older adults after marital bereavement, separation or divorce: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Brodbeck, Jeannette; Berger, Thomas; Znoj, Hans Joerg

    2017-01-13

    Marital bereavement and separation or divorce are among the most stressful critical life events in later life. These events require a dissolution of social and emotional ties, adjustments in daily routine and changes in identity and perspectives for the future. After a normative grief or distress reaction, most individuals cope well with the loss. However, some develop a prolonged grief reaction. Internet-based self-help interventions have proved beneficial for a broad range of disorders, including complicated grief. Based on the task model and the dual-process model of coping with bereavement, we developed a guided internet-based self-help intervention for individuals who experienced marital bereavement, separation or divorce at least 6 months prior to enrolment. The intervention consists of 10 text-based self-help sessions and one supportive email a week. The primary purpose of this study is the evaluation of the feasibility and efficacy of the intervention compared with a waiting control group. The secondary purpose is to compare the effects in bereaved and separated participants. Furthermore, we aim to analyze other predictors, moderators and mediators of the outcome, such as age, psychological distress and intensity of use of the intervention. The design is a randomized controlled trial with a waiting control condition of 12 weeks and a 24-weeks follow-up. At least 72 widowed or separated participants will be recruited via our study website and internet forums. Primary outcomes are reductions in grief symptoms, depression and psychological distress. Secondary outcome measures are related to loneliness, satisfaction with life, embitterment and the sessions. The trial will provide insights into the acceptance and efficacy of internet-based interventions among adults experiencing grief symptoms, psychological distress and adaptation problems in daily life after spousal bereavement, separation or divorce. Findings will add to existing knowledge by (1) evaluating

  2. Microstripes for transport and separation of magnetic particles

    DEFF Research Database (Denmark)

    Donolato, Marco; Dalslet, Bjarke Thomas; Hansen, Mikkel Fougt

    2012-01-01

    We present a simple technique for creating an on-chip magnetic particle conveyor based on exchange-biased permalloy microstripes. The particle transportation relies on an array of stripes with a spacing smaller than their width in conjunction with a periodic sequence of four different externally...... applied magnetic fields. We demonstrate the controlled transportation of a large population of particles over several millimeters of distance as well as the spatial separation of two populations of magnetic particles with different magnetophoretic mobilities. The technique can be used for the controlled...... selective manipulation and separation of magnetically labelled species. (C) 2012 American Institute of Physics....

  3. H2-control and the separation principle for discrete-time jump systems with the Markov chain in a general state space

    Science.gov (United States)

    Figueiredo, Danilo Zucolli; Costa, Oswaldo Luiz do Valle

    2017-10-01

    This paper deals with the H2 optimal control problem of discrete-time Markov jump linear systems (MJLS) considering the case in which the Markov chain takes values in a general Borel space ?. It is assumed that the controller has access only to an output variable and to the jump parameter. The goal, in this case, is to design a dynamic Markov jump controller such that the H2-norm of the closed-loop system is minimised. It is shown that the H2-norm can be written as the sum of two H2-norms, such that one of them does not depend on the control, and the other one is obtained from the optimal filter for an infinite-horizon filtering problem. This result can be seen as a separation principle for MJLS with Markov chain in a Borel space ? considering the infinite time horizon case.

  4. A local maximum in gibberellin levels regulates maize leaf growth by spatial control of cell division.

    Science.gov (United States)

    Nelissen, Hilde; Rymen, Bart; Jikumaru, Yusuke; Demuynck, Kirin; Van Lijsebettens, Mieke; Kamiya, Yuji; Inzé, Dirk; Beemster, Gerrit T S

    2012-07-10

    Plant growth rate is largely determined by the transition between the successive phases of cell division and expansion. A key role for hormone signaling in determining this transition was inferred from genetic approaches and transcriptome analysis in the Arabidopsis root tip. We used the developmental gradient at the maize leaf base as a model to study this transition, because it allows a direct comparison between endogenous hormone concentrations and the transitions between dividing, expanding, and mature tissue. Concentrations of auxin and cytokinins are highest in dividing tissues, whereas bioactive gibberellins (GAs) show a peak at the transition zone between the division and expansion zone. Combined metabolic and transcriptomic profiling revealed that this GA maximum is established by GA biosynthesis in the division zone (DZ) and active GA catabolism at the onset of the expansion zone. Mutants defective in GA synthesis and signaling, and transgenic plants overproducing GAs, demonstrate that altering GA levels specifically affects the size of the DZ, resulting in proportional changes in organ growth rates. This work thereby provides a novel molecular mechanism for the regulation of the transition from cell division to expansion that controls organ growth and size. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Spatial analysis of instream nitrogen loads and factors controlling nitrogen delivery to streams in the southeastern United States using spatially referenced regression on watershed attributes (SPARROW) and regional classification frameworks

    Science.gov (United States)

    Hoos, Anne B.; McMahon, Gerard

    2009-01-01

    Understanding how nitrogen transport across the landscape varies with landscape characteristics is important for developing sound nitrogen management policies. We used a spatially referenced regression analysis (SPARROW) to examine landscape characteristics influencing delivery of nitrogen from sources in a watershed to stream channels. Modelled landscape delivery ratio varies widely (by a factor of 4) among watersheds in the southeastern United States—higher in the western part (Tennessee, Alabama, and Mississippi) than in the eastern part, and the average value for the region is lower compared to other parts of the nation. When we model landscape delivery ratio as a continuous function of local-scale landscape characteristics, we estimate a spatial pattern that varies as a function of soil and climate characteristics but exhibits spatial structure in residuals (observed load minus predicted load). The spatial pattern of modelled landscape delivery ratio and the spatial pattern of residuals coincide spatially with Level III ecoregions and also with hydrologic landscape regions. Subsequent incorporation into the model of these frameworks as regional scale variables improves estimation of landscape delivery ratio, evidenced by reduced spatial bias in residuals, and suggests that cross-scale processes affect nitrogen attenuation on the landscape. The model-fitted coefficient values are logically consistent with the hypothesis that broad-scale classifications of hydrologic response help to explain differential rates of nitrogen attenuation, controlling for local-scale landscape characteristics. Negative model coefficients for hydrologic landscape regions where the primary flow path is shallow ground water suggest that a lower fraction of nitrogen mass will be delivered to streams; this relation is reversed for regions where the primary flow path is overland flow.

  6. A direct numerical simulation investigation of the synthetic jet frequency effects on separation control of low-Re flow past an airfoil

    KAUST Repository

    Zhang, Wei

    2015-05-05

    We present results of direct numerical simulations of a synthetic jet (SJ) based separation control of flow past a NACA-0018 (National Advisory Committee for Aeronautics) airfoil, at 10° angle of attack and Reynolds number 104 based on the airfoil chord length C and uniform inflow velocity U 0. The actuator of the SJ is modeled as a spanwise slot on the airfoil leeward surface and is placed just upstream of the leading edge separation position of the uncontrolled flow. The momentum coefficient of the SJ is chosen at a small value 2.13 × 10−4 normalized by that of the inflow. Three forcing frequencies are chosen for the present investigation: the low frequency (LF) F + = feC/U 0 = 0.5, the medium frequency (MF) F + = 1.0, and the high frequency (HF) F + = 4.0. We quantify the effects of forcing frequency for each case on the separation control and related vortex dynamics patterns. The simulations are performed using an energy conservative fourth-order parallel code. Numerical results reveal that the geometric variation introduced by the actuator has negligible effects on the mean flow field and the leading edge separation pattern; thus, the separation control effects are attributed to the SJ. The aerodynamic performances of the airfoil, characterized by lift and lift-to-drag ratio, are improved for all controlled cases, with the F + = 1.0 case being the optimal one. The flow in the shear layer close to the actuator is locked to the jet, while in the wake this lock-in is maintained for the MF case but suppressed by the increasing turbulent fluctuations in the LF and HF cases. The vortex evolution downstream of the actuator presents two modes depending on the frequency: the vortex fragmentation and merging mode in the LF case where the vortex formed due to the SJ breaks up into several vortices and the latter merge as convecting downstream; the discrete vortices mode in the HF case where discrete vortices form and convect downstream without any fragmentation and

  7. A direct numerical simulation investigation of the synthetic jet frequency effects on separation control of low-Re flow past an airfoil

    KAUST Repository

    Zhang, Wei; Samtaney, Ravi

    2015-01-01

    We present results of direct numerical simulations of a synthetic jet (SJ) based separation control of flow past a NACA-0018 (National Advisory Committee for Aeronautics) airfoil, at 10° angle of attack and Reynolds number 104 based on the airfoil chord length C and uniform inflow velocity U 0. The actuator of the SJ is modeled as a spanwise slot on the airfoil leeward surface and is placed just upstream of the leading edge separation position of the uncontrolled flow. The momentum coefficient of the SJ is chosen at a small value 2.13 × 10−4 normalized by that of the inflow. Three forcing frequencies are chosen for the present investigation: the low frequency (LF) F + = feC/U 0 = 0.5, the medium frequency (MF) F + = 1.0, and the high frequency (HF) F + = 4.0. We quantify the effects of forcing frequency for each case on the separation control and related vortex dynamics patterns. The simulations are performed using an energy conservative fourth-order parallel code. Numerical results reveal that the geometric variation introduced by the actuator has negligible effects on the mean flow field and the leading edge separation pattern; thus, the separation control effects are attributed to the SJ. The aerodynamic performances of the airfoil, characterized by lift and lift-to-drag ratio, are improved for all controlled cases, with the F + = 1.0 case being the optimal one. The flow in the shear layer close to the actuator is locked to the jet, while in the wake this lock-in is maintained for the MF case but suppressed by the increasing turbulent fluctuations in the LF and HF cases. The vortex evolution downstream of the actuator presents two modes depending on the frequency: the vortex fragmentation and merging mode in the LF case where the vortex formed due to the SJ breaks up into several vortices and the latter merge as convecting downstream; the discrete vortices mode in the HF case where discrete vortices form and convect downstream without any fragmentation and

  8. Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

    Science.gov (United States)

    Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin

    2015-11-01

    Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO3)2 into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO3)2, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO3)2 content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N2, CO2, and O2 of 37.5, 19.8, and 55.5 m3 cm/m2 h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO3)2 can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.

  9. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Science.gov (United States)

    Yoo, Hana; Park, Soojin

    2010-06-01

    We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm × 5 cm.

  10. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hana; Park, Soojin, E-mail: spark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulsan 689-798 (Korea, Republic of)

    2010-06-18

    We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm x 5 cm.

  11. Evaluation of automatic dose rate control for flat panel imaging using a spatial frequency domain figure of merit

    Science.gov (United States)

    Dehairs, M.; Bosmans, H.; Desmet, W.; Marshall, N. W.

    2017-08-01

    Current automatic dose rate controls (ADRCs) of dynamic x-ray imaging systems adjust their acquisition parameters in response to changes in patient thickness in order to achieve a constant signal level in the image receptor. This work compares a 3 parameter (3P) ADRC control to a more flexible 5-parameter (5P) method to meet this goal. A phantom composed of 15 composite poly(methyl) methacrylate (PMMA)/aluminium (Al) plates was imaged on a Siemens Artis Q dynamic system using standard 3P and 5P ADRC techniques. Phantom thickness covered a water equivalent thickness (WET) range of 2.5 cm to 37.5 cm. Acquisition parameter settings (tube potential, tube current, pulse length, copper filtration and focus size) and phantom entrance air kerma rate (EAKR) were recorded as the thickness changed. Signal difference to noise ratio (SDNR) was measured using a 0.3 mm iron insert centred in the PMMA stack, positioned at the system isocentre. SDNR was then multiplied by modulation transfer function (MTF) based correction factors for focal spot penumbral blurring and motion blurring, to give a spatial frequency dependent parameter, SDNR(u). These MTF correction factors were evaluated for an object motion of 25 mm s-1 and at a spatial frequency of 1.4 mm-1 in the object plane, typical for cardiac imaging. The figure of merit (FOM) was calculated as SDNR(u)²/EAKR for the two ADRC regimes. Using 5P versus 3P technique showed clear improvements over all thicknesses. Averaged over clinically relevant adult WET values (20 cm-37.5 cm), EAKR was reduced by 13% and 27% for fluoroscopy and acquisition modes, respectively, while the SDNR(u) based FOM increased by 16% and 34% for fluoroscopy and acquisition. In conclusion, the generalized FOM, taking into account the influence of focus size and object motion, showed benefit in terms of image quality and patient dose for the 5-parameter control over 3-parameter method for the ADRC programming of dynamic x-ray imaging systems.

  12. Microseismic Monitoring of Stimulating Shale Gas Reservoir in SW China: 2. Spatial Clustering Controlled by the Preexisting Faults and Fractures

    Science.gov (United States)

    Chen, Haichao; Meng, Xiaobo; Niu, Fenglin; Tang, Youcai; Yin, Chen; Wu, Furong

    2018-02-01

    Microseismic monitoring is crucial to improving stimulation efficiency of hydraulic fracturing treatment, as well as to mitigating potential induced seismic hazard. We applied an improved matching and locating technique to the downhole microseismic data set during one treatment stage along a horizontal well within the Weiyuan shale gas play inside Sichuan Basin in SW China, resulting in 3,052 well-located microseismic events. We employed this expanded catalog to investigate the spatiotemporal evolution of the microseismicity in order to constrain migration of the injected fluids and the associated dynamic processes. The microseismicity is generally characterized by two distinctly different clusters, both of which are highly correlated with the injection activity spatially and temporarily. The distant and well-confined cluster (cluster A) is featured by relatively large-magnitude events, with 40 events of M -1 or greater, whereas the cluster in the immediate vicinity of the wellbore (cluster B) includes two apparent lineations of seismicity with a NE-SW trending, consistent with the predominant orientation of natural fractures. We calculated the b-value and D-value, an index of fracture complexity, and found significant differences between the two seismicity clusters. Particularly, the distant cluster showed an extremely low b-value ( 0.47) and D-value ( 1.35). We speculate that the distant cluster is triggered by reactivation of a preexisting critically stressed fault, whereas the two lineations are induced by shear failures of optimally oriented natural fractures associated with fluid diffusion. In both cases, the spatially clustered microseismicity related to hydraulic stimulation is strongly controlled by the preexisting faults and fractures.

  13. Geospatial cryptography: enabling researchers to access private, spatially referenced, human subjects data for cancer control and prevention.

    Science.gov (United States)

    Jacquez, Geoffrey M; Essex, Aleksander; Curtis, Andrew; Kohler, Betsy; Sherman, Recinda; Emam, Khaled El; Shi, Chen; Kaufmann, Andy; Beale, Linda; Cusick, Thomas; Goldberg, Daniel; Goovaerts, Pierre

    2017-07-01

    As the volume, accuracy and precision of digital geographic information have increased, concerns regarding individual privacy and confidentiality have come to the forefront. Not only do these challenge a basic tenet underlying the advancement of science by posing substantial obstacles to the sharing of data to validate research results, but they are obstacles to conducting certain research projects in the first place. Geospatial cryptography involves the specification, design, implementation and application of cryptographic techniques to address privacy, confidentiality and security concerns for geographically referenced data. This article defines geospatial cryptography and demonstrates its application in cancer control and surveillance. Four use cases are considered: (1) national-level de-duplication among state or province-based cancer registries; (2) sharing of confidential data across cancer registries to support case aggregation across administrative geographies; (3) secure data linkage; and (4) cancer cluster investigation and surveillance. A secure multi-party system for geospatial cryptography is developed. Solutions under geospatial cryptography are presented and computation time is calculated. As services provided by cancer registries to the research community, de-duplication, case aggregation across administrative geographies and secure data linkage are often time-consuming and in some instances precluded by confidentiality and security concerns. Geospatial cryptography provides secure solutions that hold significant promise for addressing these concerns and for accelerating the pace of research with human subjects data residing in our nation's cancer registries. Pursuit of the research directions posed herein conceivably would lead to a geospatially encrypted geographic information system (GEGIS) designed specifically to promote the sharing and spatial analysis of confidential data. Geospatial cryptography holds substantial promise for accelerating the

  14. Gas separating

    Science.gov (United States)

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  15. Isotope separation

    International Nuclear Information System (INIS)

    Rosevear, A.; Sims, H.E.

    1985-01-01

    sup(195m)Au for medical usage is separated from sup(195m)Hg in a solution containing ions of sup(195m)Hg by contacting the solution with an adsorbing agent to adsorb 195 Hgsup(H) thereon, followed by selective elution of sup(195m)Au generated by radioactive decay of the sup(195m)Hg. The adsorbing agent comprises a composite material in the form of an inert porous inorganic substrate (e.g. Kieselguhr),the pores of which are occupied by a hydrogel of a polysaccharide (e.g. agarose) carrying terminal thiol groups for binding Hgsup(H) ions. (author)

  16. Evaluation of processes controlling the geochemical constituents in deep groundwater in Bangladesh: Spatial variability on arsenic and boron enrichment

    International Nuclear Information System (INIS)

    Halim, M.A.; Majumder, R.K.; Nessa, S.A.; Hiroshiro, Y.; Sasaki, K.; Saha, B.B.; Saepuloh, A.; Jinno, K.

    2010-01-01

    Forty-six deep groundwater samples from highly arsenic affected areas in Bangladesh were analyzed in order to evaluate the processes controlling geochemical constituents in the deep aquifer system. Spatial trends of solutes, geochemical modeling and principal component analysis indicate that carbonate dissolution, silicate weathering and ion exchange control the major-ion chemistry. The groundwater is dominantly of Na-Cl type brackish water. Approximately 17% of the examined groundwaters exhibit As concentrations higher than the maximum acceptable limit of 10 μg/L for drinking water. Strong correlation (R 2 = 0.67) of Fe with dissolved organic carbon (DOC) and positive saturation index of siderite suggests that the reductive dissolution of Fe-oxyhydroxide in presence of organic matter is considered to be the dominant process to release high content of Fe (median 0.31 mg/L) in the deep aquifer. In contrast, As is not correlated with Fe and DOC. Boron concentration in the 26% samples exceeds the standard limit of 500 μg/L, for water intended for human consumption. Negative relationships of B/Cl ratio with Cl and boron with Na/Ca ratio demonstrate the boron in deep groundwater is accompanied by brackish water and cation exchange within the clayey sediments.

  17. Controls over spatial and seasonal variations on isotopic composition of the precipitation along the central and eastern portion of Brazil.

    Science.gov (United States)

    Gastmans, Didier; Santos, Vinícius; Galhardi, Juliana Aparecida; Gromboni, João Felipe; Batista, Ludmila Vianna; Miotlinski, Konrad; Chang, Hung Kiang; Govone, José Silvio

    2017-10-01

    Based on Global Network Isotopes in Precipitation (GNIP) isotopic data set, a review of the spatial and temporal variability of δ 18 O and δ 2 H in precipitation was conducted throughout central and eastern Brazil, indicating that dynamic interactions between Intertropical and South Atlantic Convergence Zones, Amazon rainforest, and Atlantic Ocean determine the variations on the isotopic composition of precipitation over this area. Despite the seasonality and latitude effects observed, a fair correlation with precipitation amount was found. In addition, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) air mass back trajectories were used to quantify the factors controlling daily variability in stable isotopes in precipitation. Through a linear multiple regression analysis, it was observed that temporal variations were consistent with the meteorological parameters derived from HYSPLIT, particularly precipitation amount along the trajectory and mix depth, but are not dependent on vapour residence time in the atmosphere. These findings also indicate the importance of convective systems to control the isotopic composition of precipitation in tropical and subtropical regions.

  18. ELGA and TOR installations control device to carry out experiments on-line with a mass-separator by the ASNAPP-2 code

    International Nuclear Information System (INIS)

    Arvai, Z.; Guyash, Ya.; Kuznetsov, V.V.; Fominykh, V.I.

    1984-01-01

    The control device of the tor beta-spectrometer with toroidal magnetic field and the ELGA spectrometer with semiconductor detectors for investigation of conversion electrons, positrons, γ- and α-radiations and lifetime of excited states and periods of isotopes half-decay are described. The block-diagram of the measurement processes, algorithm of the ELGA devce operation, control device circuit, and circuit for connection of analog-to-digital converter with the CAMAC dataway, block-diagram of step motor control, and step motor feeding scheme as well as mechanical and electrical characteristics of the step motor are given. The device is used for spectroscopic investigations of short-lived isotopes on the accelerator proton beam with mass separator

  19. Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin, E-mail: chemist@126.com, E-mail: liushouxin@126.com [Northeast Forestry University, College of Material Science and Engineering (China)

    2015-11-15

    Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO{sub 3}){sub 2} into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO{sub 3}){sub 2}, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO{sub 3}){sub 2} content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N{sub 2}, CO{sub 2}, and O{sub 2} of 37.5, 19.8, and 55.5 m{sup 3} cm/m{sup 2} h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO{sub 3}){sub 2} can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.Graphical abstractNi-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO{sub 3}){sub 2} into the liquefied larch. The porous structure can be tailored by the amount of Ni(NO{sub 3}){sub 2}, and the Ni and NiO nanoparticles incorporated in the carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation and gas permseparation.

  20. Model for spatial synthesis of automated control system of the GCR type reactor; Model za prostornu sintezu sistema automatskog upravljanja reaktora GCR tipa

    Energy Technology Data Exchange (ETDEWEB)

    Lazarevic, B; Matausek, M [Institut za nuklearne nauke ' Boris Kidric' , Vinca, Belgrade (Yugoslavia)

    1966-07-01

    This paper describes the model which was developed for synthesis of spatial distribution of automated control elements in the reactor. It represents a general reliable mathematical model for analyzing transition states and synthesis of the automated control and regulation systems of GCR type reactors. One-dimensional system was defined under assumption that the time dependence of parameters of the neutron diffusion equation are identical in the total volume of the reactor and that spatial distribution of neutrons is time independent. It is shown that this assumption is satisfactory in case of short term variations which are relevant for safety analysis.

  1. Synthesis of Silicalite Membrane with an Aluminum-Containing Surface for Controlled Modification of Zeolitic Pore Entries for Enhanced Gas Separation

    Directory of Open Access Journals (Sweden)

    Shaowei Yang

    2018-02-01

    Full Text Available The separation of small molecule gases by membrane technologies can help performance enhancement and process intensification for emerging advanced fossil energy systems with CO2 capture capacity. This paper reports the demonstration of controlled modification of zeolitic channel size for the MFI-type zeolite membranes to enhance the separation of small molecule gases such as O2 and N2. Pure-silica MFI-type zeolite membranes were synthesized on porous α-alumina disc substrates with and without an aluminum-containing thin skin on the outer surface of zeolite membrane. The membranes were subsequently modified by on-stream catalytic cracking deposition (CCD of molecular silica to reduce the effective openings of the zeolitic channels. Such a pore modification caused the transition of gas permeation from the N2-selective gaseous diffusion mechanism in the pristine membrane to the O2-selective activated diffusion mechanism in the modified membrane. The experimental results indicated that the pore modification could be effectively limited within the aluminum-containing surface of the MFI zeolite membrane to minimize the mass transport resistance for O2 permeation while maintaining its selectivity. The implications of pore modification on the size-exclusion-enabled gas selectivity were discussed based on the kinetic molecular theory. In light of the theoretical analysis, experimental investigation was performed to further enhance the membrane separation selectivity by chemical liquid deposition of silica into the undesirable intercrystalline spaces.

  2. Visualization of boundary layer separation and passive flow control on airfoils and bodies in wind-tunnel and in-flight experiments

    Directory of Open Access Journals (Sweden)

    Matejka Milan

    2012-04-01

    Full Text Available Infrared camera, Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds numbers transition mechanism. Airfoils of Wortmann FX66 series and FX66 series wing-fuselage interaction, as well as modern airfoils and their wing-fuselage geometry were subject to study. The presence of previously identified structures in the CFD modelling, such as horse-shoe vortices, was confirmed in the flow. Wind-tunnels and in-flight measurements on sailplanes were carried out and effect of passive flow control devices - vortex generators - was surveyed; namely counter-rotating vortex generators and Zig-zag type turbulators were applied. Separation suppression and consequent drag coefficient reduction of test aircrafts was reached. PIV investigation was further extended by Time-Resolved techniques. An important study on structure of the turbulent flow in the lower atmosphere, creating an environment of the soaring flight, was presented.

  3. Visualization of boundary layer separation and passive flow control on airfoils and bodies in wind-tunnel and in-flight experiments

    Science.gov (United States)

    Popelka, Lukas; Kuklova, Jana; Simurda, David; Souckova, Natalie; Matejka, Milan; Uruba, Vaclav

    2012-04-01

    Infrared camera, Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds numbers transition mechanism. Airfoils of Wortmann FX66 series and FX66 series wing-fuselage interaction, as well as modern airfoils and their wing-fuselage geometry were subject to study. The presence of previously identified structures in the CFD modelling, such as horse-shoe vortices, was confirmed in the flow. Wind-tunnels and in-flight measurements on sailplanes were carried out and effect of passive flow control devices - vortex generators - was surveyed; namely counter-rotating vortex generators and Zig-zag type turbulators were applied. Separation suppression and consequent drag coefficient reduction of test aircrafts was reached. PIV investigation was further extended by Time-Resolved techniques. An important study on structure of the turbulent flow in the lower atmosphere, creating an environment of the soaring flight, was presented.

  4. Inorganic nanoparticles for the spatial and temporal control of organic reactions: Applications to radical degradation of biopolymer networks

    Science.gov (United States)

    Walker, Joan Marie

    Nanoparticles of gold and iron oxide not only possess remarkable optical and magnetic properties, respectively, but are also capable of influencing their local environment with an astounding degree of precision. Using nanoparticles to direct the reactivity of organic molecules near their surface provides a unique method of spatial and temporal control. Enediynes represent an exceptional class of compounds that are thermally reactive to produce a diradical intermediate via Bergman cycloaromatization. While natural product enediynes are famously cytotoxic, a rich chemistry of synthetic enediynes has developed utilizing creative means to control this reactivity through structure, electronics, metal chelation, and external triggering mechanisms. In a heretofore unexplored arena for Bergman cyclization, we have investigated the reactivity of enediynes in connection with inorganic nanoparticles in which the physical properties of the nanomaterial are directly excited to thermally promote aromatization. As the first example of this methodology, gold nanoparticles conjugated with (Z)-octa-4-en-2,6-diyne-1,8-dithiol were excited with 514 nm laser irradiation. The formation of aromatic and polymeric products was confirmed through Raman spectroscopy and electron microscopy. Water soluble analogues Au-PEG-EDDA and Fe3O4-PEG-EDDA (EDDA = (Z)-octa-4-en-2,6-diyne-1,8-diamine) show similar reactivity under laser irradiation or alternating magnetic field excitation, respectively. Furthermore, we have used these functionalized nanoparticles to attack proteinaceous substrates including fibrin and extracellular matrix proteins, capitalizing on the ability of diradicals to disrupt peptidic bonds. By delivering a locally high payload of reactive molecules and thermal energy to the large biopolymer, network restructuring and collapse is achieved. As a synthetic extension towards multifunctional nanoparticles, noble metal seed-decorated iron oxides have also been prepared and assessed for

  5. Active Control of Flow Separation on a High-Lift System with Slotted Flap at High Reynolds Number

    Science.gov (United States)

    Khodadoust, Abdollah; Washburn, Anthony

    2007-01-01

    The NASA Energy Efficient Transport (EET) airfoil was tested at NASA Langley's Low- Turbulence Pressure Tunnel (LTPT) to assess the effectiveness of distributed Active Flow Control (AFC) concepts on a high-lift system at flight scale Reynolds numbers for a medium-sized transport. The test results indicate presence of strong Reynolds number effects on the high-lift system with the AFC operational, implying the importance of flight-scale testing for implementation of such systems during design of future flight vehicles with AFC. This paper describes the wind tunnel test results obtained at the LTPT for the EET high-lift system for various AFC concepts examined on this airfoil.

  6. Comparing Spatial Predictions

    KAUST Repository

    Hering, Amanda S.

    2011-11-01

    Under a general loss function, we develop a hypothesis test to determine whether a significant difference in the spatial predictions produced by two competing models exists on average across the entire spatial domain of interest. The null hypothesis is that of no difference, and a spatial loss differential is created based on the observed data, the two sets of predictions, and the loss function chosen by the researcher. The test assumes only isotropy and short-range spatial dependence of the loss differential but does allow it to be non-Gaussian, non-zero-mean, and spatially correlated. Constant and nonconstant spatial trends in the loss differential are treated in two separate cases. Monte Carlo simulations illustrate the size and power properties of this test, and an example based on daily average wind speeds in Oklahoma is used for illustration. Supplemental results are available online. © 2011 American Statistical Association and the American Society for Qualitys.

  7. Chaos control and synchronization in Bragg acousto-optic bistable systems driven by a separate chaotic system.

    Science.gov (United States)

    Wang, Rong; Gao, Jin-Yue

    2005-09-01

    In this paper we propose a new scheme to achieve chaos control and synchronization in Bragg acousto-optic bistable systems. In the scheme, we use the output of one system to drive two identical chaotic systems. Using the maximal conditional Lyapunov exponent (MCLE) as the criterion, we analyze the conditions for realizing chaos synchronization. Numerical calculation shows that the two identical systems in chaos with negative MCLEs and driven by a chaotic system can go into chaotic synchronization whether or not they were in chaos initially. The two systems can go into different periodic states from chaos following an inverse period-doubling bifurcation route as well when driven by a periodic system.

  8. Circulating microRNA expression pattern separates patients with anti-neutrophil cytoplasmic antibody-associated vasculitis from healthy controls

    DEFF Research Database (Denmark)

    Skoglund, C.; Carlsen, A.; Weiner, M.

    2015-01-01

    patients from healthy subjects as well as from renal transplant recipients. Loadings plots indicated similar contribution of the same miRNAs in both cohorts to the PCA. Renal engagement was important for miRNA expression but consistent correlations between estimated glomerular filtration rate and mi......Objective. Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) has an unpredictable course and better biomarkers are needed. Micro-RNAs in body fluids are protected from degradation and might be used as biomarkers for diagnosis and prognosis, here we explore the potential in AAV...... individual miRNAs were differently expressed compared to controls in both cohorts; miR-29a, -34a, -142-3p and -383 were up-regulated and miR-20a, -92a and -221 were down-regulated. Cluster analysis as well as principal component analysis (PCA) indicated that patterns of miRNA expression differentiate AAV...

  9. A Hybrid Circuit for Spoof Surface Plasmons and Spatial Waveguide Modes to Reach Controllable Band-Pass Filters.

    Science.gov (United States)

    Zhang, Qian; Zhang, Hao Chi; Wu, Han; Cui, Tie Jun

    2015-11-10

    We propose a hybrid circuit for spoof surface plasmon polaritons (SPPs) and spatial waveguide modes to develop new microwave devices. The hybrid circuit includes a spoof SPP waveguide made of two anti-symmetric corrugated metallic strips and a traditional substrate integrated waveguide (SIW). From dispersion relations, we show that the electromagnetic waves only can propagate through the hybrid circuit when the operating frequency is less than the cut-off frequency of the SPP waveguide and greater than the cut-off frequency of SIW, generating efficient band-pass filters. We demonstrate that the pass band is controllable in a large range by designing the geometrical parameters of SPP waveguide and SIW. Full-wave simulations are provided to show the large adjustability of filters, including ultra wideband and narrowband filters. We fabricate a sample of the new hybrid device in the microwave frequencies, and measurement results have excellent agreements to numerical simulations, demonstrating excellent filtering characteristics such as low loss, high efficiency, and good square ratio. The proposed hybrid circuit gives important potential to accelerate the development of plasmonic integrated functional devices and circuits in both microwave and terahertz frequencies.

  10. Avoidant personality disorder is a separable schizophrenia-spectrum personality disorder even when controlling for the presence of paranoid and schizotypal personality disorders The UCLA family study.

    Science.gov (United States)

    Fogelson, D L; Nuechterlein, K H; Asarnow, R A; Payne, D L; Subotnik, K L; Jacobson, K C; Neale, M C; Kendler, K S

    2007-03-01

    It is unresolved whether avoidant personality disorder (APD) is an independent schizophrenia (Sz)-spectrum personality disorder (PD). Some studies find APD and social anxiety symptoms (Sxs) to be separable dimensions of psychopathology in relatives (Rels) of schizophrenics while other studies find avoidant Sxs to be correlated with schizotypal and paranoid Sxs. Rates of APD among first-degree Rels of Sz probands, attention-deficit/hyperactivity disorder (ADHD) probands, and community control (CC) probands were examined. Further analyses examined rates when controlling for the presence of schizotypal (SPD) and paranoid (PPD) personality disorders, differences in APD Sxs between relative groups, and whether APD in Rels of Szs reflects a near miss for another Sz-spectrum PD. Three hundred sixty-two first-degree Rels of Sz probands, 201 relatives of ADHD probands, and 245 Rels of CC probands were interviewed for the presence of DSM-III-R Axis I and II disorders. Diagnoses, integrating family history, interview information, and medical records, were determined. APD occurred more frequently in Rels of Sz probands compared to CC probands (pavoids social or occupational activities..." and "exaggerates the potential difficulties..." 65% of the Rels of Sz probands who had diagnoses of APD were more than one criterion short of a DSM-III-R diagnosis of either SPD or PPD. This indicates that APD is a separate Sz-spectrum disorder, and not merely a sub-clinical form of SPD or PPD.

  11. Unmanned Aircraft Systems Human-in-the-Loop Controller and Pilot Acceptability Study: Collision Avoidance, Self-Separation, and Alerting Times (CASSAT)

    Science.gov (United States)

    Comstock, James R., Jr.; Ghatas, Rania W.; Vincent, Michael J.; Consiglio, Maria C.; Munoz, Cesar; Chamberlain, James P.; Volk, Paul; Arthur, Keith E.

    2016-01-01

    The Federal Aviation Administration (FAA) has been mandated by the Congressional funding bill of 2012 to open the National Airspace System (NAS) to Unmanned Aircraft Systems (UAS). With the growing use of unmanned systems, NASA has established a multi-center "UAS Integration in the NAS" Project, in collaboration with the FAA and industry, and is guiding its research efforts to look at and examine crucial safety concerns regarding the integration of UAS into the NAS. Key research efforts are addressing requirements for detect-and-avoid (DAA), self-separation (SS), and collision avoidance (CA) technologies. In one of a series of human-in-the-loop experiments, NASA Langley Research Center set up a study known as Collision Avoidance, Self-Separation, and Alerting Times (CASSAT). The first phase assessed active air traffic controller interactions with DAA systems and the second phase examined reactions to the DAA system and displays by UAS Pilots at a simulated ground control station (GCS). Analyses of the test results from Phase I and Phase II are presented in this paper. Results from the CASSAT study and previous human-in-the-loop experiments will play a crucial role in the FAA's establishment of rules, regulations, and procedures to safely, efficiently, and effectively integrate UAS into the NAS.

  12. Effectiveness of maritime safety control in different navigation zones using a spatial sequential DEA model: Yangtze River case.

    Science.gov (United States)

    Wu, Bing; Wang, Yang; Zhang, Jinfen; Savan, Emanuel Emil; Yan, Xinping

    2015-08-01

    This paper aims to analyze the effectiveness of maritime safety control from the perspective of safety level along the Yangtze River with special considerations for navigational environments. The influencing variables of maritime safety are reviewed, including ship condition, maritime regulatory system, human reliability and navigational environment. Because the former three variables are generally assumed to be of the same level of safety, this paper focuses on studying the impact of navigational environments on the level of safety in different waterways. An improved data envelopment analysis (DEA) model is proposed by treating the navigational environment factors as inputs and ship accident data as outputs. Moreover, because the traditional DEA model cannot provide an overall ranking of different decision making units (DMUs), the spatial sequential frontiers and grey relational analysis are incorporated into the DEA model to facilitate a refined assessment. Based on the empirical study results, the proposed model is able to solve the problem of information missing in the prior models and evaluate the level of safety with a better accuracy. The results of the proposed DEA model are further compared with an evidential reasoning (ER) method, which has been widely used for level of safety evaluations. A sensitivity analysis is also conducted to better understand the relationship between the variation of navigational environments and level of safety. The sensitivity analysis shows that the level of safety varies in terms of traffic flow. It indicates that appropriate traffic control measures should be adopted for different waterways to improve their safety. This paper presents a practical method of conducting maritime level of safety assessments under dynamic navigational environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Hybrid Nanomaterials with Single-Site Catalysts by Spatially Controllable Immobilization of Nickel Complexes via Photoclick Chemistry for Alkene Epoxidation.

    Science.gov (United States)

    Ghosh, Dwaipayan; Febriansyah, Benny; Gupta, Disha; Ng, Leonard Kia-Sheun; Xi, Shibo; Du, Yonghua; Baikie, Tom; Dong, ZhiLi; Soo, Han Sen

    2018-05-22

    Catalyst deactivation is a persistent problem not only for the scientific community but also in industry. Isolated single-site heterogeneous catalysts have shown great promise to overcome these problems. Here, a versatile anchoring strategy for molecular complex immobilization on a broad range of semiconducting or insulating metal oxide ( e. g., titanium dioxide, mesoporous silica, cerium oxide, and tungsten oxide) nanoparticles to synthesize isolated single-site catalysts has been studied systematically. An oxidatively stable anchoring group, maleimide, is shown to form covalent linkages with surface hydroxyl functionalities of metal oxide nanoparticles by photoclick chemistry. The nanocomposites have been thoroughly characterized by techniques including UV-visible diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, and X-ray absorption spectroscopy (XAS). The IR spectroscopic studies confirm the covalent linkages between the maleimide group and surface hydroxyl functionalities of the oxide nanoparticles. The hybrid nanomaterials function as highly efficient catalysts for essentially quantitative oxidations of terminal and internal alkenes and show molecular catalyst product selectivities even in more eco-friendly solvents. XAS studies verify the robustness of the catalysts after several catalytic cycles. We have applied the photoclick anchoring methodology to precisely control the deposition of a luminescent variant of our catalyst on the metal oxide nanoparticles. Overall, we demonstrate a general approach to use irradiation to anchor molecular complexes on oxide nanoparticles to create recyclable, hybrid, single-site catalysts that function with high selectivity in a broad range of solvents. We have achieved a facile, spatially and temporally controllable photoclick method that can potentially be extended to other ligands, catalysts, functional molecules, and surfaces.

  14. Distinct Stromal Cell Factor Combinations Can Separately Control Hematopoietic Stem Cell Survival, Proliferation, and Self-Renewal

    Directory of Open Access Journals (Sweden)

    Stefan Wohrer

    2014-06-01

    Full Text Available Hematopoietic stem cells (HSCs are identified by their ability to sustain prolonged blood cell production in vivo, although recent evidence suggests that durable self-renewal (DSR is shared by HSC subtypes with distinct self-perpetuating differentiation programs. Net expansions of DSR-HSCs occur in vivo, but molecularly defined conditions that support similar responses in vitro are lacking. We hypothesized that this might require a combination of factors that differentially promote HSC viability, proliferation, and self-renewal. We now demonstrate that HSC survival and maintenance of DSR potential are variably supported by different Steel factor (SF-containing cocktails with similar HSC-mitogenic activities. In addition, stromal cells produce other factors, including nerve growth factor and collagen 1, that can antagonize the apoptosis of initially quiescent adult HSCs and, in combination with SF and interleukin-11, produce >15-fold net expansions of DSR-HSCs ex vivo within 7 days. These findings point to the molecular basis of HSC control and expansion.

  15. Separations chemistry

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Infrared spectra of Pu(IV) polymer show effects of CO 2 adsorption and of aging. Uv light (300 nm) increases the rate of reduction of PuO 2 2+ and Pu 4+ to Pu 3+ and the Pu--U separation factor using TBP. Distribution ratios for Zr and Hf between Dowex 50W--X8 resin and H 2 SO 4 solutions were found to decrease sharply with H 2 SO 4 content. Octylphenyl acid phosphate, a mixture of monooctylphenyl and dioctylphenyl phosphoric acids, is being studied for U recovery from wet-process phosphoric acid. A study of HNO 3 leaching of Ra from U ores was completed. Effects of particle size of the packed bed on the dispersion of the boundary of the miscible phase used in oil recovery are being studied. Effects of sulfonates on toluene--n-butanol--water phase relations were determined, as were the effects of salts and solutes on the max water content of 1:1 toluene--alcohol solutions. A study was begun of hydrocarbon solubility in water--surfactant--alcohol. The mechanism of the formation of hydrous ZrO 2 --polyacrylate membranes and their use for sulfate rejection were studied. Salt rejection through hyperfiltration by clay membranes (bentonite and kaolin) was also investigated. Preliminary results are given for hyperfiltration of wood-pulping wastes by ZrO 2 membranes. 13 figures

  16. Physical Activity Improves Verbal and Spatial Memory in Older Adults with Probable Mild Cognitive Impairment: A 6-Month Randomized Controlled Trial

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    Lindsay S. Nagamatsu

    2013-01-01

    Full Text Available We report secondary findings from a randomized controlled trial on the effects of exercise on memory in older adults with probable MCI. We randomized 86 women aged 70–80 years with subjective memory complaints into one of three groups: resistance training, aerobic training, or balance and tone (control. All participants exercised twice per week for six months. We measured verbal memory and learning using the Rey Auditory Verbal Learning Test (RAVLT and spatial memory using a computerized test, before and after trial completion. We found that the aerobic training group remembered significantly more items in the loss after interference condition of the RAVLT compared with the control group after six months of training. In addition, both experimental groups showed improved spatial memory performance in the most difficult condition where they were required to memorize the spatial location of three items, compared with the control group. Lastly, we found a significant correlation between spatial memory performance and overall physical capacity after intervention in the aerobic training group. Taken together, our results provide support for the prevailing notion that exercise can positively impact cognitive functioning and may represent an effective strategy to improve memory in those who have begun to experience cognitive decline.

  17. Spatial control of bone formation using a porous polymer scaffold co-delivering anabolic rhBMP-2 and anti-resorptive agents

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    NYC Yu

    2014-01-01

    Full Text Available Current clinical delivery of recombinant human bone morphogenetic proteins (rhBMPs utilises freeze-dried collagen. Despite effective new bone generation, rhBMP via collagen can be limited by significant complications due to inflammation and uncontrolled bone formation. This study aimed to produce an alternative rhBMP local delivery system to permit more controllable and superior rhBMP-induced bone formation. Cylindrical porous poly(lactic-co-glycolic acid (PLGA scaffolds were manufactured by thermally-induced phase separation. Scaffolds were encapsulated with anabolic rhBMP-2 (20 µg ± anti-resorptive agents: zoledronic acid (5 µg ZA, ZA pre-adsorbed onto hydroxyapatite microparticles, (5 µg ZA/2 % HA or IkappaB kinase (IKK inhibitor (10 µg PS-1145. Scaffolds were inserted in a 6-mm critical-sized femoral defect in Wistar rats, and compared against rhBMP-2 via collagen. The regenerate region was examined at 6 weeks by 3D microCT and descriptive histology. MicroCT and histology revealed rhBMP-induced bone was more restricted in the PLGA scaffolds than collagen scaffolds (-92.3 % TV, p < 0.01. The regenerate formed by PLGA + rhBMP-2/ZA/HA showed comparable bone volume to rhBMP-2 via collagen, and bone mineral density was +9.1 % higher (p < 0.01. Local adjunct ZA/HA or PS-1145 significantly enhanced PLGA + rhBMP-induced bone formation by +78.2 % and +52.0 %, respectively (p ≤ 0.01. Mechanistically, MG-63 human osteoblast-like cells showed cellular invasion and proliferation within PLGA scaffolds. In conclusion, PLGA scaffolds enabled superior spatial control of rhBMP-induced bone formation over clinically-used collagen. The PLGA scaffold has the potential to avoid uncontrollable bone formation-related safety issues and to customise bone shape by scaffold design. Moreover, local treatment with anti-resorptive agents incorporated within the scaffold further augmented rhBMP-induced bone formation.

  18. Long-term impact of the World Bank Loan Project for schistosomiasis control: a comparison of the spatial distribution of schistosomiasis risk in China.

    Science.gov (United States)

    Zhang, Zhijie; Zhu, Rong; Ward, Michael P; Xu, Wanghong; Zhang, Lijuan; Guo, Jiagang; Zhao, Fei; Jiang, Qingwu

    2012-01-01

    The World Bank Loan Project (WBLP) for controlling schistosomiasis in China was implemented during 1992-2001. Its short-term impact has been assessed from non-spatial perspective, but its long-term impact remains unclear and a spatial evaluation has not previously been conducted. Here we compared the spatial distribution of schistosomiasis risk using national datasets in the lake and marshland regions from 1999-2001 and 2007-2008 to evaluate the long-term impact of WBLP strategy on China's schistosomiasis burden. A hierarchical Poisson regression model was developed in a Bayesian framework with spatially correlated and uncorrelated heterogeneities at the county-level, modeled using a conditional autoregressive prior structure and a spatially unstructured Gaussian distribution, respectively. There were two important findings from this study. The WBLP strategy was found to have a good short-term impact on schistosomiasis control, but its long-term impact was not ideal. It has successfully reduced the morbidity of schistosomiasis to a low level, but can not contribute further to China's schistosomiasis control because of the current low endemic level. A second finding is that the WBLP strategy could not effectively compress the spatial distribution of schistosomiasis risk. To achieve further reductions in schistosomiasis-affected areas, and for sustainable control, focusing on the intermediate host snail should become the next step to interrupt schistosomiasis transmission within the two most affected regions surrounding the Dongting and Poyang Lakes. Furthermore, in the lower reaches of the Yangtze River, the WBLP's morbidity control strategy may need to continue for some time until snails in the upriver provinces have been well controlled. It is difficult to further reduce morbidity due to schistosomiasis using a chemotherapy-based control strategy in the lake and marshland regions of China because of the current low endemic levels of infection. The future control

  19. Long-term impact of the World Bank Loan Project for schistosomiasis control: a comparison of the spatial distribution of schistosomiasis risk in China.

    Directory of Open Access Journals (Sweden)

    Zhijie Zhang

    Full Text Available BACKGROUND: The World Bank Loan Project (WBLP for controlling schistosomiasis in China was implemented during 1992-2001. Its short-term impact has been assessed from non-spatial perspective, but its long-term impact remains unclear and a spatial evaluation has not previously been conducted. Here we compared the spatial distribution of schistosomiasis risk using national datasets in the lake and marshland regions from 1999-2001 and 2007-2008 to evaluate the long-term impact of WBLP strategy on China's schistosomiasis burden. METHODOLOGY/PRINCIPAL FINDINGS: A hierarchical Poisson regression model was developed in a Bayesian framework with spatially correlated and uncorrelated heterogeneities at the county-level, modeled using a conditional autoregressive prior structure and a spatially unstructured Gaussian distribution, respectively. There were two important findings from this study. The WBLP strategy was found to have a good short-term impact on schistosomiasis control, but its long-term impact was not ideal. It has successfully reduced the morbidity of schistosomiasis to a low level, but can not contribute further to China's schistosomiasis control because of the current low endemic level. A second finding is that the WBLP strategy could not effectively compress the spatial distribution of schistosomiasis risk. To achieve further reductions in schistosomiasis-affected areas, and for sustainable control, focusing on the intermediate host snail should become the next step to interrupt schistosomiasis transmission within the two most affected regions surrounding the Dongting and Poyang Lakes. Furthermore, in the lower reaches of the Yangtze River, the WBLP's morbidity control strategy may need to continue for some time until snails in the upriver provinces have been well controlled. CONCLUSION: It is difficult to further reduce morbidity due to schistosomiasis using a chemotherapy-based control strategy in the lake and marshland regions of China

  20. Coupled effects of natural and anthropogenic controls on seasonal and spatial variations of river water quality during baseflow in a coastal watershed of Southeast China.

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    Jinliang Huang

    Full Text Available Surface water samples of baseflow were collected from 20 headwater sub-watersheds which were classified into three types of watersheds (natural, urban and agricultural in the flood, dry and transition seasons during three consecutive years (2010-2012 within a coastal watershed of Southeast China. Integrating spatial statistics with multivariate statistical techniques, river water quality variations and their interactions with natural and anthropogenic controls were examined to identify the causal factors and underlying mechanisms governing spatiotemporal patterns of water quality. Anthropogenic input related to industrial effluents and domestic wastewater, agricultural activities associated with the precipitation-induced surface runoff, and natural weathering process were identified as the potential important factors to drive the seasonal variations in stream water quality for the transition, flood and dry seasons, respectively. All water quality indicators except SRP had the highest mean concentrations in the dry and transition seasons. Anthropogenic activities and watershed characteristics led to the spatial variations in stream water quality in three types of watersheds. Concentrations of NH(4(+-N, SRP, K(+, COD(Mn, and Cl- were generally highest in urban watersheds. NO3(-N Concentration was generally highest in agricultural watersheds. Mg(2+ concentration in natural watersheds was significantly higher than that in agricultural watersheds. Spatial autocorrelations analysis showed similar levels of water pollution between the neighboring sub-watersheds exhibited in the dry and transition seasons while non-point source pollution contributed to the significant variations in water quality between neighboring sub-watersheds. Spatial regression analysis showed anthropogenic controls played critical roles in variations of water quality in the JRW. Management implications were further discussed for water resource management. This research