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Sample records for laminar-turbulent characteristic time

  1. Characteristics of the laminar-turbulent edge in transitional boundary layers

    NASA Astrophysics Data System (ADS)

    Lee, Jin; Zaki, Tamer

    2015-11-01

    Characteristics of the boundary separating the laminar and turbulent regions in a transitional boundary layer are examined using a time series of three-dimensional flow fields extracted from direct numerical simulations (DNS). In order to accurately mimic boundary-layer experiments perturbed by grid turbulence, the current simulation includes the leading edge of the flat plate and the incoming homogeneous isotropic turbulence. The Reynolds number based on the momentum thickness reaches up to 1400, and high-resolution three-dimensional flow fields of the DNS data will be publicly accessible via the Johns Hopkins Turbulence Database (JHTDB). The laminar-turbulence discrimination algorithm isolates the turbulence spots within the transition zone and the bounding surface of the fully-turbulent flow. Attention is placed on the cross-stream surface between the transition zone and fully-turbulent boundary layer. The shape of this interface is dictated by a balance between downstream advection, destabilization of upstream flow and merging of turbulence spots. Conditionally sampled statistics are examined across the interface, and are also compared to the downstream equilibrium turbulent boundary layer.

  2. Stochastic analysis of the time evolution of laminar-turbulent bands of plane Couette flow.

    PubMed

    Rolland, Joran

    2015-11-01

    This article is concerned with the time evolution of the oblique laminar-turbulent bands of transitional plane Couette flow under the influence of turbulent noise. Our study is focused on the amplitude of modulation of turbulence (the bands). In order to guide the numerical study of the flow, we first perform an analytical and numerical analysis of a Stochastic Ginzburg-Landau (GL) equation for a complex order parameter. The modulus of this order parameter models the amplitude of modulation of turbulence. Firstly, we compute the autocorrelation function of said modulus once the band is established. Secondly, we perform a calculation of average and fluctuations around the exponential growth of the order parameter. This type of analysis is similar to the Stochastic Structural Stability Theory (S3T). We then perform numerical simulations of the Navier-Stokes equations in order to confront these predictions with the actual behaviour of the bands. Computation of the autocorrelation function of the modulation of turbulence shows quantitative agreement with the model: in the established band regime, the amplitude of modulation follows an Ornstein-Uhlenbeck process. In order to test the S3T predictions, we perform quench experiments, sudden decreases of the Reynolds number from uniform turbulence, in which modulation appears. We compute the average evolution of the amplitude of modulation and the fluctuations around it. We find good agreement between numerics and modeling. The average trajectory grows exponentially, at a rate clearly smaller than that of the formation of laminar holes. Meanwhile, the actual time evolution remains in a flaring envelope, centered on the average, and expanding at the same rate. These results provide further validation of the stochastic modeling for the time evolution of the bands for further studies. Besides, they stress on the difference between the oblique band formation and the formation of laminar holes. PMID:26590151

  3. Stability characteristics of a supersonic boundary layer and their relation to the position of the laminar-turbulent transition point

    NASA Technical Reports Server (NTRS)

    Lysenko, V. I.

    1987-01-01

    By comparing the calculated results with experimental data, it is demonstrated that the position of the laminar-boundary transition point of a boundary layer can be estimated by using the e-exp-n method. The effect of the Mach number, pressure gradient, and heat transfer on the laminar-turbulent transition is discussed. It is found that under conditions of strong cooling, the effect of the pressure gradient on the position of the transition point is less pronounced than in the absence of heat transfer.

  4. Characteristics of disturbances in the laminar-turbulent transition of spherical Couette flow. 2. New disturbances observed for a medium gap

    NASA Astrophysics Data System (ADS)

    Nakabayashi, Koichi; Zheng, Zhiming; Tsuchida, Yoichi

    2002-11-01

    Supercritical flow in spherical Couette system with a rotating inner sphere and a fixed outer sphere has been investigated for a medium gap of the clearance ratio 0.206 in terms of the structure, wave-number, fundamental, and rotational frequencies of disturbances. Consequently, ring vortices and traveling letter-x-like waves were found within the Ekman-type secondary flow as new disturbances, in addition to Stuart vortices and shear waves. Also, interior waves were found within toroidal Taylor-Gortler (TG) vortices as a new disturbance, in addition to twists. Further, the wavy outflow boundary at the equator of the turbulent basic flow was found. Each ring vortex occurring successively around the pole moves toward the pole for one wavelength in the meridian direction (theta]=10[deg) while it rotates for one wavelength in the azimuthal direction (phi]=90[deg), because it has four traveling waves. The rotational direction of Stuart vortices is opposite to that of the inner sphere. The wave speed (rotation frequency) of interior waves or twists is the same as that of oscillating inflow boundary between two toroidal TG vortex cells, and the wave speed of shear waves is the same as that of the oscillating outflow boundary between the toroidal TG vortex cell and the Ekman-type secondary flow. Also, the wave speed of the oscillating outflow boundary is about two times the oscillating inflow boundary.

  5. Laminar-turbulent transition prediction module for LOGOS package

    NASA Astrophysics Data System (ADS)

    Boiko, A. V.; Nechepurenko, Yu. M.; Zhuchkov, R. N.; Kozelkov, A. S.

    2014-04-01

    The present work is devoted to a description and substantiation of an original module for computing the location of laminar-turbulent transition in subsonic boundary layer flows, which is based on the e N -method and enables more accurate computations of the flow around bodies in the presence of the so-called natural transition to turbulence in the boundary layer. A combined work of the module and the RANS solver from the aerodynamic part of the LOGOS package is demonstrated by the example of the flow past a flat plate. The obtained computed locations of the beginning and the end of the laminar-turbulent transition coincide with known reference values.

  6. Laminar-Turbulent Transition Behind Discrete Roughness Elements in a High-Speed Boundary Layer

    NASA Technical Reports Server (NTRS)

    Choudhari, Meelan M.; Li, Fei; Wu, Minwei; Chang, Chau-Lyan; Edwards, Jack R., Jr.; Kegerise, Michael; King, Rudolph

    2010-01-01

    Computations are performed to study the flow past an isolated roughness element in a Mach 3.5, laminar, flat plate boundary layer. To determine the effects of the roughness element on the location of laminar-turbulent transition inside the boundary layer, the instability characteristics of the stationary wake behind the roughness element are investigated over a range of roughness heights. The wake flow adjacent to the spanwise plane of symmetry is characterized by a narrow region of increased boundary layer thickness. Beyond the near wake region, the centerline streak is surrounded by a pair of high-speed streaks with reduced boundary layer thickness and a secondary, outer pair of lower-speed streaks. Similar to the spanwise periodic pattern of streaks behind an array of regularly spaced roughness elements, the above wake structure persists over large distances and can sustain strong enough convective instabilities to cause an earlier onset of transition when the roughness height is sufficiently large. Time accurate computations are performed to clarify additional issues such as the role of the nearfield of the roughness element during the generation of streak instabilities, as well as to reveal selected details of their nonlinear evolution. Effects of roughness element shape on the streak amplitudes and the interactions between multiple roughness elements aligned along the flow direction are also investigated.

  7. Decaying turbulence at the laminar-turbulence transition in a pipe

    NASA Astrophysics Data System (ADS)

    Goldenfeld, Nigel; Hsieh, Tsung-Lin; Shih, Hong-Yan

    2015-11-01

    As a follow-up to Donnelly's pioneering research on the decay of superfluid turbulence in a pipe, we have studied a different regime: transitional turbulence. Near the onset to turbulence in a pipe, turbulent puffs decay either directly or through splitting, with characteristic time-scales that exhibit a super-exponential dependence on Reynolds number. Using direct numerical simulations of transitional pipe flow, we show that a collective mode, a so-called zonal flow emerges at large scales, activated by anisotropic turbulent fluctuations, as measured in terms of Reynolds stress. This zonal flow imposes a shear on the turbulent fluctuations that tends to suppress their anisotropy, leading to stochastic oscillatory dynamics. These results motivate the proposal that the laminar-turbulence non-equilibrium phase transition can be modeled by an effective theory, usefully thought of as predator-prey dynamics, leading to a predicted universality class of directed percolation. This work was partially supported by the National Science Foundation through grant NSF-DMR-1044901.

  8. Oblique laminar-turbulent interfaces in plane shear flows

    NASA Astrophysics Data System (ADS)

    Duguet, Yohann; Schlatter, Philipp

    2012-11-01

    In many wall-bounded shear flows, turbulence can spread in the presence of finite-amplitude perturbations despite the linear stability of the base flow. The onset of the transitional regime is usually characterised by the formation of large-scale oblique patterns of alternatively laminar and turbulent flow. Yet the mechanism responsible for the observed obliqueness has so far remained mysterious. In this talk we will focus on the formation of such oblique structures in plane Couette flow, using both analytical arguments and intensive direct numerical simulations. We will suggest a robust mechanism for the obliqueness of the incipient turbulent spots derived from mass and momentum budgets in the regions close to the laminar/turbulent interfaces.

  9. Oblique laminar-turbulent interfaces in plane shear flows.

    PubMed

    Duguet, Yohann; Schlatter, Philipp

    2013-01-18

    Localized structures such as turbulent stripes and turbulent spots are typical features of transitional wall-bounded flows in the subcritical regime. Based on an assumption for scale separation between large and small scales, we show analytically that the corresponding laminar-turbulent interfaces are always oblique with respect to the mean direction of the flow. In the case of plane Couette flow, the mismatch between the streamwise flow rates near the boundaries of the turbulence patch generates a large-scale flow with a nonzero spanwise component. Advection of the small-scale turbulent fluctuations (streaks) by the corresponding large-scale flow distorts the shape of the turbulence patch and is responsible for its oblique growth. This mechanism can be easily extended to other subcritical flows such as plane Poiseuille flow or Taylor-Couette flow. PMID:23373928

  10. Oblique Laminar-Turbulent Interfaces in Plane Shear Flows

    NASA Astrophysics Data System (ADS)

    Duguet, Yohann; Schlatter, Philipp

    2013-01-01

    Localized structures such as turbulent stripes and turbulent spots are typical features of transitional wall-bounded flows in the subcritical regime. Based on an assumption for scale separation between large and small scales, we show analytically that the corresponding laminar-turbulent interfaces are always oblique with respect to the mean direction of the flow. In the case of plane Couette flow, the mismatch between the streamwise flow rates near the boundaries of the turbulence patch generates a large-scale flow with a nonzero spanwise component. Advection of the small-scale turbulent fluctuations (streaks) by the corresponding large-scale flow distorts the shape of the turbulence patch and is responsible for its oblique growth. This mechanism can be easily extended to other subcritical flows such as plane Poiseuille flow or Taylor-Couette flow.

  11. Numerical studies on laminar-turbulent transition in boundary layers

    NASA Astrophysics Data System (ADS)

    Yang, Kyung Soo

    Laminar-turbulent transition in flat-plate boundary layers is investigated by direct numerical solution of the full Navier-Stokes equations. Both forced transition (in parallel Blasius flow excited by a vibrating ribbon) and natural transition (in a decelerating boundary layer) are studied. In both cases, an initial state containing random noise is employed to eliminate bias in selecting unstable waves. In the simulations of ribbon-induced transition, close agreement with experiments (Saric et al. (1984)) is obtained for low amplitude 2-D Tollmien-Schlichting waves, producing subharmonic breakdown (C- or H-type). For high amplitudes, a mixture of subharmonic and fundamental structures is observed. Clear-cut fundamental breakdown (K-type) is never obtained. In the simulation of the early stages of natural transition in a decelerating boundary layer, 2-D and/or slightly oblique waves initially grow due to the inflectional instability. When they become strong enough, they initiate a secondary instability leading to 3-D distortion and A vortices, in good agreement with experiments (Gad-el-Hak et al. (1984)). It was found that the tips of the A vortices are rarely aligned with the flow direction, and that they appear locally in space. A simple wave interference model accounting for these features of natural transition was developed. It suggests that multiple waves are active in the secondary instability, and that they are determined by unpredictable initial disturbances. The later stages of transition in a decelerating boundary layer were also studied with higher numerical resolution. Our results indicate that the naturally-born A vortices undergo breakdown processes similar to those of ribbon-induced A vortices. Conversely, this justifies the conventional approach to study laminar-turbulent transition, the vibrating-ribbon technique.

  12. Active control of laminar-turbulent transition using instantaneous vorticity signals at the wall

    NASA Astrophysics Data System (ADS)

    Gmelin, Christoph; Rist, Ulrich

    2001-02-01

    Many approaches with the objective to actively delay the laminar-turbulent transition in boundary layers are currently under investigation. These approaches, which are mostly based on the superposition of anti-phase disturbances, fail in cases where high (nonlinear) disturbance amplitudes occur. One possible solution to overcome this problem is the direct feedback of instantaneous flow signals from the wall. In our case the spanwise vorticity (ωz) on the wall is sensed, multiplied by a certain factor A and prescribed as a new boundary condition at the wall with some time delay Δt. This procedure (called ωz-control ) yields a robust algorithm which is less influenced by nonlinearities than other processes based on the linear superposition of disturbances (waves). The method was developed and evaluated using both linear stability theory and a three-dimensional spatial DNS code solving the complete Navier-Stokes equations.

  13. Stochastic and deterministic motion of a laminar-turbulent front in a spanwisely extended Couette flow.

    PubMed

    Duguet, Yohann; Le Maître, Olivier; Schlatter, Philipp

    2011-12-01

    We investigate numerically the dynamics of a laminar-turbulent interface in a spanwisely extended and streamwisely minimal plane Couette flow. The chosen geometry allows one to suppress the large-scale secondary flow and to focus on the nucleation of streaks near the interface. It is shown that the resulting spanwise motion of the interface is essentially stochastic and can be modeled as a continuous-time random walk. This model corresponds here to a Gaussian diffusion process. The average speed of the interface and the corresponding diffusion coefficient are determined as functions of the Reynolds number Re, as well as the threshold value above which turbulence contaminates the whole domain. For the lowest values of Re, the stochastic dynamics competes with another deterministic regime of growth of the localized perturbations. The latter is interpreted as a depinning process from the homoclinic snaking region of the system. PMID:22304198

  14. On the determination of the position of laminar-turbulent transition in boundary layer by optical methods

    NASA Astrophysics Data System (ADS)

    Bountin, D. A.; Gromyko, Yu. V.; Maslov, A. A.; Polivanov, P. A.; Sidorenko, A. A.

    2015-11-01

    As a rule, aerodynamic studies at hypersonic flow velocities are carried out in short-duration wind-tunnel facilities. For such facilities, optical diagnostic methods are most preferable. In the present study, we give for the first time a comparison of two methods for determining the end of laminar-turbulent transition: from the distribution of heat fluxes and from schlieren visualization data for the boundary-layer flow. Parametric data on the position of the transition are obtained. These data can be used in the future as reference ones while calibrating semi-empirical calculation models for the transition.

  15. DPIV, LDV and SSS investigations of forced laminar-turbulent transition

    NASA Astrophysics Data System (ADS)

    Bobba, Kumar; Gharib, Morteza; Doyle, John

    2004-11-01

    A systematical experimental study conducted to understand the role of external environment---free stream turbulence---on the boundary layer laminar-turbulent transition on a flat plate will be presented. The experiments are conducted in the GALCIT free surface water tunnel using flow visualization, DPIV, and MEMS based LDV and shear stress sensors (SSS). The results indicate that various transition parameters like shape factor, skin friction coefficient, mean profile, etc., are strong function of the external turbulence level. Neither T-S waves nor turbulent spots were found, but the flow is always embedded with stream wise vortical structures in the parametric range explored. An interesting observation is that the vortical structures are found even at such low Reynolds numbers as 289 (based on displacement thickness). A real time study of the structures in the flow shed more light on their dynamics and evolution. Space-time auto-correlation functions and probability density functions revealed that the wavelength of the span wise and stream wise structures in the boundary layer are independent of the Reynolds number in the parametric range explored. Finally, the experimental observations are compared with the results from our robust flow stability theory and the agreement is good.

  16. On the laminar-turbulent transition in injection-driven porous chambers

    NASA Astrophysics Data System (ADS)

    Gazanion, B.; Chedevergne, F.; Casalis, G.

    2014-01-01

    This paper presents a characterization of the laminar-turbulent transition in a cold flow setup, representative of the flow in a solid rocket motor. Recent developments based on a linear stability analysis of this particular flow have highlighted the existence of intrinsic instabilities, generating the so-called parietal vortex shedding, responsible for thrust oscillations. From this essential ingredient, an original interpretation of the laminar-turbulent transition is proposed using three approaches. Eventually, a description of the laminar and turbulent areas is obtained for the entire flow, from which a transition line is defined.

  17. Bifurcation model of the laminar-turbulent transition in simple flows

    NASA Astrophysics Data System (ADS)

    Eriklintsev, I. V.; Kozlov, S. A.

    2015-03-01

    For plane channel flows with a constant pressure gradient and for constant-pressure shear layer flows, a simple closure scheme for the Reynolds-averaged Navier-Stokes equations is proposed as an alternative to eddy-viscosity-based models. The closure scheme makes it possible to compute flows at any Reynolds number, including near the laminar-turbulent transition.

  18. Predicting the effects of surface roughness on laminar-turbulent transition for axisymmetric bodies

    NASA Astrophysics Data System (ADS)

    Casarella, M. J.; Niedzwecki, J. M.

    1980-07-01

    A procedure for assessing the effects of uniformly distributed surface roughness on the location of laminar-turbulent transition is presented. A dimensionless roughness Reynolds number is defined which allows one to isolate the effects of body shape on causing premature transition due to roughness. A comparative evaluation of the sensitivity of body shape to tripping the flow can be made by examining the variation of the new roughness Reynolds number along the surface from a class of geometric shapes. The results demonstrate that secondary effects such as roughness can play a critical role in the location of the laminar-turbulent transition. Extensive numerical results were obtained for elliptical forebodies. Their sensitivity to roughness and the determination of critical roughness heights over a wide range of body Reynolds numbers are presented. For these shapes, it was found that the critical roughness height could be expressed as a function of the body Reynolds number.

  19. Direct laminar-turbulent transition in Taylor-Couette flow: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Crowley, Christopher J.; Krygier, Michael; Raben, Samuel G.; Borrero, Daniel; Grigoriev, Roman O.; Schatz, Michael F.

    2014-11-01

    The transition to turbulence in Taylor-Couette flow is frequently mediated by stable flow states (e.g. interpenetrating spirals). We describe a direct laminar-turbulent transition in a system with counterrotating cylinders and small aspect ratio of 5.26. In experiments probed using tomographic PIV and direct numerical simulations with realistic boundary conditions, we find the transition is hysteretic, yet highly reproducible with turbulence triggered by the growth of weak spiral flows. This study was supported by NSF DMS-1125302 and NSF CMMI-1234436.

  20. Nonlinear dynamics of laminar-turbulent transition in three dimensional Rayleigh-Benard convection

    NASA Astrophysics Data System (ADS)

    Evstigneev, N. M.; Magnitskii, N. A.; Sidorov, S. V.

    2010-10-01

    This paper proposes a new approach to analysis of incompressible 3D fluid motion in Rayleigh-Benard convection in transition from laminar to turbulent regimes. Number of test series were conducted. The analysis indicated that in different test series laminar-turbulent transition follows either the subharmonic bifurcation cascade of two-dimensional tori or the subharmonic bifurcation cascade of limit cycles. Cycles up to the third period were found in the system that indicated the end of the Sharkovskii sequence. All bifurcation cascades agree with the Feigenbaum-Sharkovskii-Magnitskii (FSM) scenario.

  1. Experimental study for the detection of the laminar/turbulent aerodynamic transition on a wing aircraft, using fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Molin, S.; Dolfi, D.; Doisy, M.; Seraudie, A.; Arnal, D.; Coustols, E.; Mandle, J.

    2010-09-01

    We demonstrate the feasibility of detection of the nature (laminar/turbulent/transitional) of the aerodynamic boundary layer of a profile of a wing aircraft model, using a Distributed FeedBack (DFB) Fiber Laser as optical fiber sensor. Signals to be measured are pressure variations : ΔP~1Pa at few 100Hz in the laminar region and ΔP~10Pa at few kHz in the turbulent region. Intermittent regime occurring in-between these two regions (transition) is characterized by turbulent bursts in laminar flow. Relevant pressure variations have been obtained in a low-speed research-type wind tunnel of ONERA Centre of Toulouse. In order to validate the measurements, a "classical" hot film sensor, the application and use of which have been formerly developed and validated by ONERA, has been placed at the neighborhood of the fiber sensor. The hot film allows measurement of the boundary layer wall shear stress whose characteristics are a well known signature of the boundary layer nature (laminar, intermittent or turbulent) [1]. In the three regimes, signals from the fiber sensor and the hot film sensor are strongly correlated, which allows us to conclude that a DFB fiber laser sensor is a good candidate for detecting the boundary layer nature, and thus for future integration in an aircraft wing. The work presented here has been realized within the framework of "Clean Sky", a Joint Technology Initiative of the European Union.

  2. Transitional regime and laminar-turbulent coexistence in the asymptotic suction boundary layer

    NASA Astrophysics Data System (ADS)

    Khapko, Taras; Schlatter, Philipp; Duguet, Yohann; Henningson, Dan

    2015-11-01

    We study numerically the asymptotic suction boundary layer (ASBL) in the transitional regime on the verge of laminarization. Starting from a turbulent state the Reynolds number Re is decreased in small steps until the laminar state is established. This study protocol allows not only to investigate the regime at the onset of turbulence, but also to identify the critical Reynolds number Reg ~ 270 , below which turbulence is not sustained. In other planar shear flows the transitional regime at the onset takes the form of stable laminar-turbulent bands, however in ASBL no regime of sustained laminar-turbulent coexistence has been identified. The flow stays fully turbulent even at the lowest Re before laminarization. During the laminarization process streamwise turbulent and laminar avenues are created with no oblique interfaces between the two. This behavior is connected with the existence of a large-scale vertical transport, the feature that distinguishes ASBL from the other wall-bounded shear flows. After an artificial forcing is added canceling all spanwise and wall-normal fluctuations above y+ = 100 , transient oblique bands are observed similar to the ones in other subcritical shear flows, while the flow later laminarizes or becomes fully turbulent again.

  3. Laminar-turbulent patterning in wall-bounded shear flows: a Galerkin model

    NASA Astrophysics Data System (ADS)

    Seshasayanan, K.; Manneville, P.

    2015-06-01

    On its way to turbulence, plane Couette flow-the flow between counter-translating parallel plates-displays a puzzling steady oblique laminar-turbulent pattern. We approach this problem via Galerkin modelling of the Navier-Stokes equations. The wall-normal dependence of the hydrodynamic field is treated by means of expansions on functional bases fitting the boundary conditions exactly. This yields a set of partial differential equations for spatiotemporal dynamics in the plane of the flow. Truncating this set beyond the lowest nontrivial order is numerically shown to produce the expected pattern, therefore improving over what was obtained at the cruder effective wall-normal resolution. Perspectives opened by this approach are discussed.

  4. Supersonic quiet-tunnel development for laminar-turbulent transition research

    NASA Technical Reports Server (NTRS)

    Schneider, Steven P.

    1995-01-01

    This grant supported research into quiet-flow supersonic wind-tunnels, between February 1994 and February 1995. Quiet-flow nozzles operate with laminar nozzle-wall boundary layers, in order to provide low-disturbance flow for studies of laminar-turbulent transition under conditions comparable to flight. Major accomplishments include: (1) development of the Purdue Quiet-Flow Ludwieg Tube, (2) computational evaluation of the square nozzle concept for quiet-flow nozzles, and (3) measurement of the presence of early transition on the flat sidewalls of the NASA LaRC Mach 3.5 supersonic low-disturbance tunnel. Since items (1) and (2) are described in the final report for companion grant NAG1-1133, only item (3) is described here. A thesis addressing the development of square nozzles for high-speed, low-disturbance wind tunnels is included as an appendix.

  5. Laminar-turbulent transition of channel flows: the effect of neutrally buoyant finite-size particles

    NASA Astrophysics Data System (ADS)

    Abbas, Micheline; Loisel, Vincent; Masbernat, Olivier; Climent, Eric

    2013-11-01

    Numerical simulations were performed on channel flows laden with resolved finite-size neutrally buoyant particles at moderate volumetric concentration. In the case of fluctuating flows close to laminar-turbulent transition, the particle volume fraction is homogeneously distributed in the channel except an accumulation layer in the near-wall region (particle migration is driven by inertia). Particles increase the level of perturbations close to the wall leading to significant enhancement of both the velocity fluctuations and the wall friction coefficient. Additionally, particles break down the large-scale flow structures into smaller, more numerous and sustained eddies. When the flow Reynolds number is decreased, flow relaminarization occurs at critical Reynolds number RecS (based on the effective suspension viscosity) significantly below the critical Reynolds number Rec of single-phase flow transition. In the case of laminar flows, the suspension segregates into pure fluid and particle laden wall layers due to cross-stream migration. An instability is observed characterized by the formation of dune-like patterns at the separation between pure fluid and concentrated suspension. Increasing the Reynolds number yields transition to turbulence at a threshold above RecS . This work was granted access to the HPC resources of CALMIP and GENCI under the allocations 2012-P1002 and x20132a6942 respectively.

  6. On the growth of laminar-turbulent patterns in plane Couette flow

    NASA Astrophysics Data System (ADS)

    Manneville, Paul

    2012-06-01

    The growth of laminar-turbulent band patterns in plane Couette flow is studied in the vicinity of the global stability threshold Reg below which laminar flow ultimately prevails. Appropriately tailored direct numerical simulations are performed to manage systems extended enough to accommodate several bands. The initial state or germ is an oblique turbulent patch of limited extent. The growth is seen to result from several competing processes: (i) nucleation of turbulent patches close to or at the extremities of already formed band segments, with the same obliquity as the germ or the opposite one, and (ii) turbulence collapse similar to gap formation for band decay. Growth into a labyrinthine pattern is observed as soon as spanwise expansion is effective. An ideally aligned pattern is usually obtained at the end of a long and gradual regularization stage when Re is large enough. Stable isolated bands can be observed slightly above Reg. When growth rates are not large enough, the germ decays at the end of a long transient, similarly to what was observed in experiments. Local continuous growth/decay microscopic mechanisms are seen to compete with large deviations which are the cause of mesoscopic nucleation events (turbulent patches or laminar gaps) controlling the macroscopic behaviour of the system (pattern). The implications of these findings are discussed in the light of Pomeau's proposals based on directed percolation and first-order phase transitions in statistical physics.

  7. Development of quiet-flow supersonic wind tunnels for laminar-turbulent transition research

    NASA Technical Reports Server (NTRS)

    Schneider, Steven P.

    1994-01-01

    This grant supported research into quiet-flow supersonic wind-tunnels, between May 1990 and December 1994. Quiet-flow nozzles operate with laminar nozzle-wall boundary layers, in order to provide low-disturbance flow for studies of laminar-turbulent transition under conditions comparable to flight. Major accomplishments include: (1) the design, fabrication, and performance-evaluation of a new kind of quiet tunnel, a quiet-flow Ludweig tube; (2) the integration of preexisting codes for nozzle design, 2D boundary-layer computation, and transition-estimation into a single user-friendly package for quiet-nozzle design; and (3) the design and preliminary evaluation of supersonic nozzles with square cross-section, as an alternative to conventional quiet-flow nozzles. After a brief summary of (1), a description of (2) is presented. Published work describing (3) is then summarized. The report concludes with a description of recent results for the Tollmien-Schlichting and Gortler instability in one of the square nozzles previously analyzed.

  8. Constrained large-eddy simulation of laminar-turbulent transition in channel flow

    NASA Astrophysics Data System (ADS)

    Zhao, Yaomin; Xia, Zhenhua; Shi, Yipeng; Xiao, Zuoli; Chen, Shiyi

    2014-09-01

    A constrained large-eddy simulation (CLES) of a laminar-turbulent transition in a temporally developing channel flow is performed. First, we confirm the capability of CLES to simulate this transition problem using the a priori Reynolds stress estimated from a direct numerical simulation. Based on the analysis of the Reynolds stress during the transition process, an intermittency factor is introduced in the Reynolds-averaged Navier-Stokes equation (RANS) model to account for the transition property. Two simple approaches are used to construct the intermittency factor. One is based on the shape factor, and the other is based on the coefficients of Smagorinsky models. The CLES results using the intermittency modified RANS model can accurately predict the onset of the transition and the basic transition process, in a manner similar to a large eddy simulation with dynamics Smagorinsky model (LES-DSM). Meanwhile, CLES preserves its advantage over LES-DSM in the turbulent state. The present work illustrates that CLES can be used to simulate transitional flows.

  9. Predator-prey effective model for the laminar-turbulent transition in a pipe

    NASA Astrophysics Data System (ADS)

    Shih, Hong-Yan; Hsieh, Tsung-Lin; Goldenfeld, Nigel

    2015-11-01

    The goal of our work is to understand the phenomenology of the laminar-turbulent transition in terms of standard phase transition concepts, and to calculate the universality class from first principles. Direct numerical simulations (DNS) of transitional pipe flow show that a collective mode -- a zonal flow -- is activated by Reynolds stress and suppresses turbulence subsequently, leading to stochastic predator-prey-like oscillations. Here we describe in detail the effective stochastic theory for such spatial-extended predator-prey modes. We present Monte Carlo simulations of the effective theory, showing that it reproduces the phenomenology of pipe flow experiments, including the phase diagram of puff decay and splitting. In particular, the theory predicts a super-exponential lifetime statistics for both puff decay and puff-splitting, in agreement with experimental data on pipe flow, and can be mapped exactly to the field theory of directed percolation. Our calculations strongly suggest that transitional turbulence in pipes is in the universality class of directed percolation. This work was partially supported by the National Science Foundation through grant NSF-DMR-1044901.

  10. Laminar-Turbulent Transition: A Hysteresis Curve of Two Critical Reynolds Numbers in Pipe Flow

    NASA Astrophysics Data System (ADS)

    Kanda, Hidesada

    2006-11-01

    A laminar-turbulent transition model (DFD 2004) has been constructed for pipe flows: (1) Natural transition occurs in the entrance region, and (2) Entrance shape determines a critical Reynolds number Rc. To verify the model, we have carried out experiments similar to Reynolds's color-dye experiment with 5 bellmouth entrances and a straight pipe. Then, we observed the following: (i) two different types of Rc exist, Rc1 from laminar to turbulent and Rc2 from turbulent to laminar, and (ii) the ratio of bellmouth diameter BD to pipe diameter D affects the values of Rc1 and Rc2. For each entrance, Rc1 has a maximum value Rc1(max) and Rc2 has a minimum value Rc2(min). When overlapping the two curves of Rc1(max) and Rc2(min) against BD/D, a hysteresis curve is confirmed. All Rc values exist inside this hysteresis curve. Consequently, Rc takes a minimum value Rc(min) of approximately 2000 when BD/D is at a minimum, i.e., at BD/D = 1, Rc(min) = Rc1(max) = Rc2(min) = 2000. Regarding Reynolds's Rc of 12,830, we observed Rc1(max) of approximately 13,000 at BD/D above 1.54. Therefore, the model has been partly verified.

  11. Prediction of laminar-turbulent transition on an airfoil at high level of free-stream turbulence

    NASA Astrophysics Data System (ADS)

    Chernoray, V.

    2015-06-01

    Prediction of laminar-turbulent transition at high level of free-stream turbulence in boundary layers of airfoil geometries with external pressure gradient changeover is in focus. The aim is a validation of a transition model for transition prediction in turbomachinery applications. Numerical simulations have been performed by using a transition model by Langtry and Menter for a number of different cases of pressure gradient, at Reynolds-number range, based on the airfoil chord, 50 000 ≤ Re ≤ 500 000, and free-stream turbulence intensities 2% and 4%. The validation of the computational results against the experimental data showed good performance of used turbulence model for all test cases.

  12. Nonlinear Dynamics of Laminar-Turbulent Transition in Back Facing Step Problem for Bolzmann Equations in Hydrodynamic Limit

    NASA Astrophysics Data System (ADS)

    Evstigneev, N. M.; Magnitskii, N. A.

    2010-09-01

    A numerical analysis of laminar-turbulent transition regime for the back facing step problem is considered. The initial-boundary problem is posed for Boltzmann integral-differential equations for very small Knudsen number limit Ű hydrodynamic limit. In order to consider nonlinear high accuracy analysis a high order numerical method is used to solve Boltzmann equations. The analysis revealed that the formation of turbulent transition in the initial-boundary value problem is represented by the Feigenbaum Sarkovskii Magnitskii scenario. However the transition process is different from the results of Navier-Stokes equations solution of the same initial boundary value problem.

  13. On active control of laminar-turbulent transition on two-dimensional wings.

    PubMed

    Erdmann, Ralf; Pätzold, Andreas; Engert, Marcus; Peltzer, Inken; Nitsche, Wolfgang

    2011-04-13

    This paper gives an overview of drag reduction on aerofoils by means of active control of Tollmien-Schlichting (TS) waves. Wind-tunnel experiments at Mach numbers of up to M(x)=0.42 and model Reynolds numbers of up to Re(c)=2 × 10(6), as well as in-flight experiments on a wing glove at Mach numbers of M<0.1 and at a Reynolds number of Re(c)=2.4 × 10(6), are presented. Surface hot wires were used to detect the linearly growing TS waves in the transitional boundary layer. Different types of voice-coil- and piezo-driven membrane actuators, as well as active-wall actuators, located between the reference and error sensors, were demonstrated to be effective in introducing counter-waves into the boundary layer to cancel the travelling TS waves. A control algorithm based on the filtered-x least mean square (FxLMS) approach was employed for in-flight and high-speed wind-tunnel experiments. A model-predictive control algorithm was tested in low-speed experiments on an active-wall actuator system. For the in-flight experiments, a reduction of up to 12 dB (75% TS amplitude) was accomplished in the TS frequency range between 200 and 600 Hz. A significant reduction of up to 20 dB (90% TS amplitude) in the flow disturbance amplitude was achieved in high-speed wind-tunnel experiments in the fundamental TS frequency range between 3 and 8 kHz. A downstream shift of the laminar-turbulent transition of up to seven TS wavelengths is presented. The cascaded sensor-actuator arrangement given by Sturzebecher & Nitsche in 2003 for low-speed wind-tunnel experiments was able to shift the transition Δx=240 mm (18% x/c) downstream by a TS amplitude reduction of 96 per cent (30 dB). By using an active-wall actuator, which is much shorter than the cascaded system, a transition delay of seven TS wavelengths (16 dB TS amplitude reduction) was reached. PMID:21382820

  14. Large-eddy simulation of laminar-turbulent breakdown at high speeds with dynamic subgrid-scale modeling

    NASA Technical Reports Server (NTRS)

    El-Hady, Nabil M.

    1993-01-01

    The laminar-turbulent breakdown of a boundary-layer flow along a hollow cylinder at Mach 4.5 is investigated with large-eddy simulation. The subgrid scales are modeled dynamically, where the model coefficients are determined from the local resolved field. The behavior of the dynamic-model coefficients is investigated through both an a priori test with direct numerical simulation data for the same case and a complete large-eddy simulation. Both formulations proposed by Germano et al. and Lilly are used for the determination of unique coefficients for the dynamic model and their results are compared and assessed. The behavior and the energy cascade of the subgrid-scale field structure are investigated at various stages of the transition process. The investigations are able to duplicate a high-speed transition phenomenon observed in experiments and explained only recently by the direct numerical simulations of Pruett and Zang, which is the appearance of 'rope-like' waves. The nonlinear evolution and breakdown of the laminar boundary layer and the structure of the flow field during the transition process were also investigated.

  15. Laminar-turbulent flow around a wedge placed on sharp and blunted plates

    NASA Astrophysics Data System (ADS)

    Borovoy, V.; Mosharov, V.; Radchenko, V.; Noev, A.

    2012-01-01

    The flow structure and heat transfer on sharp and blunted plates near a wedge have been studied experimentally at Mach number 6 and two Reynolds numbers corresponding to laminar and transitional boundary layers ahead of the wedge. Similarly to the two-dimensional (2D) flow, the plate's blunting causes a decrease of heat transfer at threedimensional (3D) interference between the boundary layer and the shock wave. However, there is a threshold bluntness value beyond which the influence is negligible. Heat transfer and pressure measurements as well as surface flow visualization have been performed by means of panoramic (global) methods based on the use of luminescent coatings. They have been used in a short duration (pulse) wind tunnel for the first time.

  16. Laminar-turbulent transition; Proceedings of the IUTAM Symposium, Ecole Nationale Superieure de l'Aeronautique et de l'Espace, Toulouse, France, Sept. 11-15, 1989

    NASA Astrophysics Data System (ADS)

    Arnal, D.; Michel, R.

    The present conference discusses such topics in laminar-turbulent transition phenomena as the TS instability in similar boundary layer flows affected by an adverse pressure gradient, flight tests of a swept wing with suction, piezofoil arrays for airfoil flow instability investigations, the breakdown of a wave packet disturbance in a laminar boundary layer, a stability theory for chemically reacting flows, the subharmonic instability of compressible boundary layers, and wall turbulence in Blasius flow. Also discussed are stability-based methods for transition in three-dimensional flows, blunt-nosed swept supercritical LFC wings without nose flaps, the Goertler vortex instability mechanism at hypersonic speeds, wavy vortices in rotating channel flow, large-eddy simulations of mixing layers, boundary-layer tripping in supersonic flow, and visualizations of the boundary-layer transition.

  17. Characteristic Time Scales of Characteristic Magmatic Processes and Systems

    NASA Astrophysics Data System (ADS)

    Marsh, B. D.

    2004-05-01

    Every specific magmatic process, regardless of spatial scale, has an associated characteristic time scale. Time scales associated with crystals alone are rates of growth, dissolution, settling, aggregation, annealing, and nucleation, among others. At the other extreme are the time scales associated with the dynamics of the entire magmatic system. These can be separated into two groups: those associated with system genetics (e.g., the production and transport of magma, establishment of the magmatic system) and those due to physical characteristics of the established system (e.g., wall rock failure, solidification front propagation and instability, porous flow). The detailed geometry of a specific magmatic system is particularly important to appreciate; although generic systems are useful, care must be taken to make model systems as absolutely realistic as possible. Fuzzy models produce fuzzy science. Knowledge of specific time scales is not necessarily useful or meaningful unless the hierarchical context of the time scales for a realistic magmatic system is appreciated. The age of a specific phenocryst or ensemble of phenocrysts, as determined from isotopic or CSD studies, is not meaningful unless something can be ascertained of the provenance of the crystals. For example, crystal size multiplied by growth rate gives a meaningful crystal age only if it is from a part of the system that has experienced semi-monotonic cooling prior to chilling; crystals entrained from a long-standing cumulate bed that were mechanically sorted in ascending magma may not reveal this history. Ragged old crystals rolling about in the system for untold numbers of flushing times record specious process times, telling more about the noise in the system than the life of typical, first generation crystallization processes. The most helpful process-related time scales are those that are known well and that bound or define the temporal style of the system. Perhaps the most valuable of these times comes from the observed durations and rates of volcanism. There can be little doubt that the temporal styles of volcanism are the same as those of magmatism in general. Volcano repose times, periodicity, eruptive fluxes, acoustic emission structures, lava volumes, longevity, etc. must also be characteristic of pluton-dominated systems. We must therefore give up some classical concepts (e.g., instantaneous injection of crystal-free magma as an initial condition) for any plutonic/chambered system and move towards an integrated concept of magmatism. Among the host of process-related time scales, probably the three most fundamental of any magmatic system are (1) the time scale associated with crystal nucleation (J) and growth (G) (tx}=C{1(G3 J)-{1}/4; Zieg & Marsh, J. Pet. 02') along with the associated scales for mean crystal size (L) and population (N), (2) the time scale associated with conductive cooling controlled by a local length scale (d) (tc}=C{2 d2/K; K is thermal diffusivity), and (3) the time scale associated with intra-crystal diffusion (td}=C{3 L2/D; D is chemical diffusivity). It is the subtle, clever, and insightful application of time scales, dovetailed with realistic system geometry and attention paid to the analogous time scales of volcanism, that promises to reveal the true dynamic integration of magmatic systems.

  18. Stochastic Modeling of Laminar-Turbulent Transition

    NASA Technical Reports Server (NTRS)

    Rubinstein, Robert; Choudhari, Meelan

    2002-01-01

    Stochastic versions of stability equations are developed in order to develop integrated models of transition and turbulence and to understand the effects of uncertain initial conditions on disturbance growth. Stochastic forms of the resonant triad equations, a high Reynolds number asymptotic theory, and the parabolized stability equations are developed.

  19. Characteristics of time-varying inductance

    NASA Astrophysics Data System (ADS)

    Boteler, D. H.

    1994-03-01

    When an ac current pushes an inductor into saturation for part of each cycle, the inductor presents two values of inductance to the rest of the circuit. This situation can arise either deliberately, as in the operation of a fluxgate magnetometer, or unintentionally, as with the saturation of power transformers by geomagnetically induced currents. Analyzing such a circuit can be laborious, but often all that is required is knowledge of how the changing inductance affects slowly varying components of the current. It is shown that the effective inductance seen by slowly varying currents flowing through a time-varying inductance is given by 1/L(sub eff) = theta/L(sub 1) + (1 - theta)/L(sub 2), where theta is the proportion of time for which the inductance has value L(sub 1). This expression is comparable to that for the effective inductance of two uncoupled inductors in parallel, but allowing for the proportion of time that each one is seen by the rest of the circuit. For power transformers, where the unsaturated inductance is considerably greater than the saturated inductance, the term involving the larger inductance quickly becomes negligible as the proportion of time in saturation increases. Thus, beyond very mild saturation, the effective inductance seen by slowly varying currents flowing through the transformer is inversely related to the proportion of time in saturation.

  20. Predicting river travel time from hydraulic characteristics

    USGS Publications Warehouse

    Jobson, H.E.

    2001-01-01

    Predicting the effect of a pollutant spill on downstream water quality is primarily dependent on the water velocity, longitudinal mixing, and chemical/physical reactions. Of these, velocity is the most important and difficult to predict. This paper provides guidance on extrapolating travel-time information from one within bank discharge to another. In many cases, a time series of discharge (such as provided by a U.S. Geological Survey stream gauge) will provide an excellent basis for this extrapolation. Otherwise, the accuracy of a travel time extrapolation based on a resistance equation can be greatly improved by assuming the total flow area is composed of two parts, an active and an inactive area. For 60 reaches of 12 rivers with slopes greater than about 0.0002, travel times could be predicted to within about 10% by computing the active flow area using the Manning equation with n = 0.035 and assuming a constant inactive area for each reach. The predicted travel times were not very sensitive to the assumed values of bed slope or channel width.

  1. Timing characteristics of Large Area Picosecond Photodetectors

    NASA Astrophysics Data System (ADS)

    Adams, B. W.; Elagin, A.; Frisch, H. J.; Obaid, R.; Oberla, E.; Vostrikov, A.; Wagner, R. G.; Wang, J.; Wetstein, M.

    2015-09-01

    The LAPPD Collaboration was formed to develop ultrafast large-area imaging photodetectors based on new methods for fabricating microchannel plates (MCPs). In this paper we characterize the time response using a pulsed, sub-picosecond laser. We observe single-photoelectron time resolutions of a 20 cm × 20 cm MCP consistently below 70 ps, spatial resolutions of roughly 500 μm, and median gains higher than 107. The RMS measured at one particular point on an LAPPD detector is 58 ps, with ± 1σ of 47 ps. The differential time resolution between the signal reaching the two ends of the delay line anode is measured to be 5.1 ps for large signals, with an asymptotic limit falling below 2 ps as noise-over-signal approaches zero.

  2. Timing Characteristics of Large Area Picosecond Photodetectors

    SciTech Connect

    Adams, Bernhard W.; Elagin, Andrey L.; Frisch, H.; Obaid, Razib; Oberla, E; Vostrikov, Alexander; Wagner, Robert G.; Wang, Jingbo; Wetstein, Matthew J.; Northrop, R

    2015-09-21

    The LAPPD Collaboration was formed to develop ultralast large-area imaging photodetectors based on new methods for fabricating microchannel plates (MCPs). In this paper we characterize the time response using a pulsed, sub picosecond laser. We observe single photoelectron time resolutions of a 20 cm x 20 cm MCP consistently below 70 ps, spatial resolutions of roughly 500 pm, and median gains higher than 10(7). The RMS measured at one particular point on an LAPPD detector is 58 ps, with in of 47 ps. The differential time resolution between the signal reaching the two ends of the delay line anode is measured to be 5.1 ps for large signals, with an asymptotic limit falling below 2 ps as noise-over-signal approaches zero.

  3. Time-Resolved Visualization of Görtler Vortices in a Pulsed Convex Wall Jet using Fast Pressure-Sensitive Paint

    NASA Astrophysics Data System (ADS)

    Gregory, James; Danon, Ron; Greenblatt, David

    2015-11-01

    The time-resolved formation and structure of Görtler vortices in a pulsed convex wall jet are studied in this work. While the presence of Görtler vortices in laminar boundary layers on concave surfaces can be clearly observed, their presence in wall jets flowing over convex surfaces is difficult to discern due to transition to turbulence in the outer part of the jet. This work employed fast-response pressure-sensitive paint (PSP), which has a documented flat frequency response greater than 5 kHz, to visualize the time-resolved formation of the wall jet and the details of the Görtler vortices. The radius of curvature of the wall jet was 8 cm, and the Reynolds number (based on slot height and jet exit velocity) was varied between 5 ×102 and 4 ×104 . The characteristic spanwise wavelength of the vortices was studied as a function of jet Reynolds number. Furthermore, as the Reynolds number was increased, various secondary instabilities were observed that led to laminar-turbulent transition. Funding provided by the U.S. Fulbright Scholar Program.

  4. Characteristic times of biased random walks on complex networks

    NASA Astrophysics Data System (ADS)

    Bonaventura, Moreno; Nicosia, Vincenzo; Latora, Vito

    2014-01-01

    We consider degree-biased random walkers whose probability to move from a node to one of its neighbors of degree k is proportional to kα, where α is a tuning parameter. We study both numerically and analytically three types of characteristic times, namely (i) the time the walker needs to come back to the starting node, (ii) the time it takes to visit a given node for the first time, and (iii) the time it takes to visit all the nodes of the network. We consider a large data set of real-world networks and we show that the value of α which minimizes the three characteristic times differs from the value αmin=-1 analytically found for uncorrelated networks in the mean-field approximation. In addition to this, we found that assortative networks have preferentially a value of αmin in the range [-1,-0.5], while disassortative networks have αmin in the range [-0.5,0]. We derive an analytical relation between the degree correlation exponent ν and the optimal bias value αmin, which works well for real-world assortative networks. When only local information is available, degree-biased random walks can guarantee smaller characteristic times than the classical unbiased random walks by means of an appropriate tuning of the motion bias.

  5. Characteristic-based time domain method for antenna analysis

    NASA Astrophysics Data System (ADS)

    Jiao, Dan; Jin, Jian-Ming; Shang, J. S.

    2001-01-01

    The characteristic-based time domain method, developed in the computational fluid dynamics community for solving the Euler equations, is applied to the antenna radiation problem. Based on the principle of the characteristic-based algorithm, a governing equation in the cylindrical coordinate system is formulated directly to facilitate the analysis of body-of-revolution antennas and also to achieve the exact Riemann problem. A finite difference scheme with second-order accuracy in both time and space is constructed from the eigenvalue and eigenvector analysis of the derived governing equation. Rigorous boundary conditions for all the field components are formulated to improve the accuracy of the characteristic-based finite difference scheme. Numerical results demonstrate the validity and accuracy of the proposed technique.

  6. TECHNICAL REPORT: Studies of ``Kapustinsky's'' light pulser timing characteristics

    NASA Astrophysics Data System (ADS)

    Lubsandorzhiev, B. K.; Vyatchin, Y. E.

    2006-06-01

    We present the results of studies of a nanosecond light pulser built following an original design of J.S. Kapustinsky et al and using bright InGaN/GaN ultraviolet and blue LEDs produced by Nichia Chemical. It is shown how timing characteristics of the pulser depend on the type of LED and the value of power supply voltage.

  7. Volume Recovery of Polystyrene: Evolution of Characteristic Relaxation Time

    NASA Astrophysics Data System (ADS)

    Simon, Sindee; Bernazzani, Paul

    2001-03-01

    The phenomenology of structural recovery observed for glass-forming materials below their glass transition temperature is well-understood; however, mathematical models of structural recovery are unable to simultaneously describe experiments performed over a wide range of thermal histories. We have developed a new experiment using intermittent temperature perturbations during volume recovery in order to obtain quantitative information concerning the evolution of the characteristic relaxation time during structural recovery. The experiments are analogous to the intermittent creep experiments developed by Struik. Using such experiments, we can test whether the characteristic relaxation time depends on the time-temperature-pressure history of the material or on the instantaneous state of the material as is assumed in most models of structural recovery. Experiments are performed using an automated capillary dilatometer and a polystyrene sample. The implications of the results will be discussed.

  8. Scaling characteristics in ozone concentration time series (OCTS).

    PubMed

    Lee, Chung-Kung; Juang, Lain-Chuen; Wang, Cheng-Cai; Liao, Yu-Ying; Yu, Chung-Chin; Liu, Yu-Chuan; Ho, Ding-Shun

    2006-02-01

    One-year series of hourly average ozone observations, which were obtained from urban and national park air monitoring stations at Taipei (Taiwan), were analyzed by means of descriptive statistics and fractal methods to examine the scaling structures of ozone concentrations. It was found that all ozone measurements exhibited the characteristic right-skewed frequency distribution, cyclic pattern, and long-term memory. A mono-fractal analysis was performed by transferring the ozone concentration time series (OCTS) into a useful compact form, namely, the box-dimension (D(B))-threshold (T(h)) and critical scale (C(S))-threshold (T(h)) plots. Scale invariance was found in these time series and the box dimension was shown to be a decreasing function of the threshold ozone level, implying the existence of multifractal characteristics. To test this hypothesis, the OCTS were transferred into the multifractal spectra, namely, the tau(q)-q plots. The analysis confirmed the existence of multifractal characteristics in the investigated OCTS. A simple two-scale Cantor set with unequal scales and weights was then used to fit the calculated tau(q)-q plots. This model fitted remarkably well the entire spectrum of scaling exponents for the examined OCTS. Because the existence of chaos behavior in OCTS has been reported in the literature, the possibility of a chaotic multifractal approach for OCTS characterization was discussed. PMID:16081138

  9. Anthropometric characteristics account for time to exhaustion in cycling.

    PubMed

    Basset, F A; Billaut, F; Joanisse, D R

    2014-12-01

    This study examined the relationship between the phenotypic and anthropometric characteristics and the cycling time to exhaustion (Tlim) at the maximal aerobic power output (Pmax). 12 (7 men, 5 women) physically-active participants performed a square-wave test at Pmax to determine the maximal time limit. Muscle histochemistry, enzymatic activities and buffer capacity were determined from a vastus lateralis muscle biopsy, lean body mass (LBM) by hydrostatic weighing, and total (TV) and lean (LV) volumes of the thigh by anthropometric measurements. The mean (±SD) Tlim was 235±84 s (score range: 108-425 s). No relationship was found between Tlim and any muscle phenotypes. However, we observed a strong, linear relationship between Tlim and LBM (r=0.84, P<0.05). Thigh TV and LV displayed weaker correlation coefficients with Tlim (r=0.66 and r=0.73, respectively; P<0.05). We further estimated the femur length and found this measure to correlate with Tlim (r=0.81, P<0.05). This study suggests that muscle phenotypes may not be representative of Tlim. Rather, anthropometric characteristics account for such performance by conferring a biomechanical advantage in cycling. We conclude that, in addition to metabolic factors, anthropometric characteristics with reasonable accuracy predict Tlim in cycling, and may account for the large inter-subject variability observed in previous studies. PMID:24977949

  10. Describing Directional Cell Migration with a Characteristic Directionality Time

    PubMed Central

    Loosley, Alex J.; O’Brien, Xian M.; Reichner, Jonathan S.; Tang, Jay X.

    2015-01-01

    Many cell types can bias their direction of locomotion by coupling to external cues. Characteristics such as how fast a cell migrates and the directedness of its migration path can be quantified to provide metrics that determine which biochemical and biomechanical factors affect directional cell migration, and by how much. To be useful, these metrics must be reproducible from one experimental setting to another. However, most are not reproducible because their numerical values depend on technical parameters like sampling interval and measurement error. To address the need for a reproducible metric, we analytically derive a metric called directionality time, the minimum observation time required to identify motion as directionally biased. We show that the corresponding fit function is applicable to a variety of ergodic, directionally biased motions. A motion is ergodic when the underlying dynamical properties such as speed or directional bias do not change over time. Measuring the directionality of nonergodic motion is less straightforward but we also show how this class of motion can be analyzed. Simulations are used to show the robustness of directionality time measurements and its decoupling from measurement errors. As a practical example, we demonstrate the measurement of directionality time, step-by-step, on noisy, nonergodic trajectories of chemotactic neutrophils. Because of its inherent generality, directionality time ought to be useful for characterizing a broad range of motions including intracellular transport, cell motility, and animal migration. PMID:25992908

  11. Optical characteristics of pesticides measured by terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Kyu; Kim, Giyoung; Son, Joo-Hiuk

    2015-07-01

    In this study, we measured the optical characteristics of pesticides by terahertz time-domain spectroscopy. Pesticide samples were prepared as pellets that were mixed with polyethylene powder and placed in the center of the path of a terahertz electromagnetic (EM) wave in the spectroscopy system. The absorbance of each sample showed obvious differences in absorption peaks. From this result, we showed that these pesticide products had resonance modes in the terahertz range, and this method can be used to make a sensor that is able to measure low concentrations of pesticides in farm produce.

  12. A time-dependent neutron transport method of characteristics formulation with time derivative propagation

    NASA Astrophysics Data System (ADS)

    Hoffman, Adam J.; Lee, John C.

    2016-02-01

    A new time-dependent Method of Characteristics (MOC) formulation for nuclear reactor kinetics was developed utilizing angular flux time-derivative propagation. This method avoids the requirement of storing the angular flux at previous points in time to represent a discretized time derivative; instead, an equation for the angular flux time derivative along 1D spatial characteristics is derived and solved concurrently with the 1D transport characteristic equation. This approach allows the angular flux time derivative to be recast principally in terms of the neutron source time derivatives, which are approximated to high-order accuracy using the backward differentiation formula (BDF). This approach, called Source Derivative Propagation (SDP), drastically reduces the memory requirements of time-dependent MOC relative to methods that require storing the angular flux. An SDP method was developed for 2D and 3D applications and implemented in the computer code DeCART in 2D. DeCART was used to model two reactor transient benchmarks: a modified TWIGL problem and a C5G7 transient. The SDP method accurately and efficiently replicated the solution of the conventional time-dependent MOC method using two orders of magnitude less memory.

  13. Magnetopause characteristics at 0840-1040 hours local time

    NASA Technical Reports Server (NTRS)

    Williams, D. J.

    1980-01-01

    An analysis of three-dimensional energetic particle distributions for 14 consecutive ISEE satellite orbits during magnetopause crossings and close approaches is presented. The data were collected from the Nov. 10 through Dec. 11, 1977, time period and cover local times of 0840 to 1040 hours. It was found that the magnetopause in this period defined by energetic particles can be represented as sharp particles and a well defined boundary for magnetospherically trapped particles for a wide range of magnetospheric activity and magnetosheath field conditions. The magnetopause position, orientation, and velocity were determined for all identified magnetopause crossings and close approaches using the technique of Williams (1979); it was found that the magnetopause is nearly always in motion with velocities ranging from near zero to at least plus or minus 25 km/s. Correlations with published plasma, magnetic field, and plasma wave magnetopause identifications show the energetic particle results to be accurate and an important factor in determining magnetopause characteristics and behavior.

  14. Real-Time Mapping alert system; characteristics and capabilities

    USGS Publications Warehouse

    Torres, L.A.; Lambert, S.C.; Liebermann, T.D.

    1995-01-01

    The U.S. Geological Survey has an extensive hydrologic network that records and transmits precipitation, stage, discharge, and other water-related data on a real-time basis to an automated data processing system. Data values are recorded on electronic data collection platforms at field sampling sites. These values are transmitted by means of orbiting satellites to receiving ground stations, and by way of telecommunication lines to a U.S. Geological Survey office where they are processed on a computer system. Data that exceed predefined thresholds are identified as alert values. The current alert status at monitoring sites within a state or region is of critical importance during floods, hurricanes, and other extreme hydrologic events. This report describes the characteristics and capabilities of a series of computer programs for real-time mapping of hydrologic data. The software provides interactive graphics display and query of hydrologic information from the network in a real-time, map-based, menu-driven environment.

  15. Linear response characteristics of time-dependent time fractional Fokker-Planck equation systems

    NASA Astrophysics Data System (ADS)

    Kang, Yan-Mei; Jiang, Yao-Lin; Yong, Xie

    2014-11-01

    The time fractional Fokker-Planck equation approach is an important tool for modeling subdiffusion. When the external field is time modulated, two types of time-dependent time fractional Fokker-Planck equations have been proposed, both reduced to the same time-dependent time fractional Fokker-Planck equation when the external field is time uncorrelated. The first type is strictly deduced as the continuous limit of the continuous time random walk with time modulated Boltzmann jumping weight, while the second type is derived by ideally assuming that the jump probabilities can be evaluated at the start of the waiting time prior to jumping. For the first time we obtain the linear response characteristic for the first type of the time fractional Fokker-Planck equation systems, and for a comparison we revisit the corresponding result for the second type of the time fractional Fokker-Planck equation systems, and the similarity and difference between them is discussed with an application example. The investigation not only helps in understanding the competition between subdiffusion and time-dependent modulation, but also has significance in accessing the spectral properties of spontaneous fluctuation and the linear dynamic susceptibility of external perturbation in subdiffusive processes.

  16. Space-Time Characteristics of Rainfall Diurnal Variations

    NASA Technical Reports Server (NTRS)

    Yang, Song; Kummerow, Chris; Olson, Bill; Smith, Eric A.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The space-time features of rainfall diurnal variation of precipitation are systematically investigated by using the Tropical Rainfall Measuring Mission (TRMM) precipitation products retrieved from TRMM microwave imager (TMI), precipitation radar (PR) and TMI/PR combined algorithms. Results demonstrate that diurnal variability of precipitation is obvious over tropical regions. The dominant feature of rainfall diurnal cycle over, ocean is that there is consistent rainfall peak in early morning, while there is a consistent rainfall peak in mid-late afternoon over land. The seasonal variation on intensity of rainfall diurnal cycle is clearly evidenced. Horizontal distributions of rainfall diurnal variations indicate that there is a clearly early-morning peak with a secondary peak in the middle-late afternoon in ocean rainfall at latitudes dominated by large-scale convergence and deep convection. There is also an analogous early-morning peak in land rainfall along with a stronger afternoon peak forced by surface heating. Amplitude analysis shows that the patterns and its evolution of rainfall diurnal cycle are very close to rainfall distribution pattern and its evolution. These results indicate that rainfall diurnal variations are strongly associated with large-scale convective systems and climate weather systems. Phase studies clearly present the regional and seasonal features of rainfall diurnal activities. Further studies on convective and stratiform rainfall show different characteristics of diurnal cycles. Their spatial and temporal variations of convective and stratiform rainfall indicate that mechanisms for rainfall diurnal variations vary with time and space.

  17. Effects of geometry on runoff time characteristics and time-area histogram of hillslopes

    NASA Astrophysics Data System (ADS)

    Sabzevari, T.; Noroozpour, S.; Pishvaei, M. H.

    2015-12-01

    Geometry (plan curvature and profile curvature) of hillslopes affects the time characteristics of overland flow such as lag time (tl) and time to equilibrium (te). The results of previous studies on the response time of overland flow over complex hillslopes express diversity of conclusions in some cases. In this research, the effects of hillslope geometry on tl and te are investigated for complex hillslopes, and the ratio of te/tl is defined as a function of the geometric characteristics of hillslopes and flow regime type. To this aim, a new topography model is first introduced and kinematic wave-based equations for computing te and tl which can consider the convergence/divergence and concavity/convexity parameters of the complex hillslopes are presented. Using the derived te equations, the location of isochrones and then the time-area histograms of the complex hillslopes are derived and compared. It is concluded that the average te for divergent hillslopes is 33% more than that for convergent ones. Convex hillslopes have longer te relative to the concave hillslopes, and the mean te of the former is 13% more than that of the latter. Although the te of convergent hillslopes is longer than that of equivalent divergent ones (with the same degree of plan curvature), the tl of the convergent hillslopes is always shorter than that of the divergent ones.

  18. Laminar-turbulent boundary in plane Couette flow.

    PubMed

    Schneider, Tobias M; Gibson, John F; Lagha, Maher; De Lillo, Filippo; Eckhardt, Bruno

    2008-09-01

    We apply the iterated edge-state tracking algorithm to study the boundary between laminar and turbulent dynamics in plane Couette flow at Re=400. Perturbations that are not strong enough to become fully turbulent or weak enough to relaminarize tend toward a hyperbolic coherent structure in state space, termed the edge state, which seems to be unique up to obvious continuous shift symmetries. The results reported here show that in cases where a fixed point has only one unstable direction, such as for the lower-branch solution in plane Couette flow, the iterated edge tracking algorithm converges to this state. They also show that the choice of initial state is not critical and that essentially arbitrary initial conditions can be used to find the edge state. PMID:18851193

  19. Measurements of Pilot Time Delay as Influenced by Controller Characteristics and Vehicles Time Delays

    NASA Technical Reports Server (NTRS)

    Privoznik, C. M.; Berry, D. T.; Bartoli, A. G.

    1984-01-01

    A study to measure and compare pilot time delay when using a space shuttle rotational hand controller and a more conventional control stick was conducted at NASA Ames Research Center's Dryden Flight Research Facility. The space shuttle controller has a palm pivot in the pitch axis. The more conventional controller used was a general-purpose engineering simulator stick that has a pivot length between that of a typical aircraft center stick and a sidestick. Measurements of the pilot's effective time delay were obtained through a first-order, closed-loop, compensatory tracking task in pitch. The tasks were implemented through a space shuttle cockpit simulator and a critical task tester device. The study consisted of 450 data runs with four test pilots and one nonpilot, and used three control stick configurations and two system delays. Results showed that the heavier conventional stick had the lowest pilot effective time delays associated with it, whereas the shuttle and light conventional sticks each had similar higher pilot time delay characteristics. It was also determined that each control stick showed an increase in pilot time delay when the total system delay was increased.

  20. Student Part-Time Employment: Characteristics and Consequences

    ERIC Educational Resources Information Center

    Robotham, David

    2012-01-01

    Purpose: The aim of the paper is to examine the consequences of students engaging in part-time employment during their studies. It reports the results of a survey of part-time employment among university students. The research examined the possible consequences of combining part-time employment with full-time study, with particular reference to…

  1. Student Part-Time Employment: Characteristics and Consequences

    ERIC Educational Resources Information Center

    Robotham, David

    2012-01-01

    Purpose: The aim of the paper is to examine the consequences of students engaging in part-time employment during their studies. It reports the results of a survey of part-time employment among university students. The research examined the possible consequences of combining part-time employment with full-time study, with particular reference to

  2. Maternal Mental Health, Neighborhood Characteristics, and Time Investments in Children

    ERIC Educational Resources Information Center

    Frech, Adrianne; Kimbro, Rachel Tolbert

    2011-01-01

    We use data from the Fragile Families and Child Wellbeing Study (N = 3,572) to examine relationships between maternal depression and mothers' time investments with their 5-year-old children in outings, trips to playgrounds or parks, time spent reading with the child, and time spent playing indoors with the child. We also examine whether mothers'

  3. Maternal Mental Health, Neighborhood Characteristics, and Time Investments in Children

    ERIC Educational Resources Information Center

    Frech, Adrianne; Kimbro, Rachel Tolbert

    2011-01-01

    We use data from the Fragile Families and Child Wellbeing Study (N = 3,572) to examine relationships between maternal depression and mothers' time investments with their 5-year-old children in outings, trips to playgrounds or parks, time spent reading with the child, and time spent playing indoors with the child. We also examine whether mothers'…

  4. EMBAYMENT CHARACTERISTIC TIME AND BIOLOGY VIA TIDAL PRISM MODEL

    EPA Science Inventory

    Transport time scales in water bodies are classically based on their physical and chemical aspects rather than on their ecological and biological character. The direct connection between a physical time scale and ecological effects has to be investigated in order to quantitativel...

  5. TIME-WALK CHARACTERISTICS OF AN IMPROVED CONSTANT FRACTION DISCRIMINATOR

    SciTech Connect

    Wozniak, G. J.; Richardson, L. W.; Maier, M. R.

    1980-09-01

    A modification to a constant fraction discriminator design published earlier makes the observed time walk less than 30 ps over an input voltage range of 0.15 to 2.5 V. This performance makes time-walk corrections unnecessary in many situations.

  6. Estimating Testing Time: The Effects of Item Characteristics on Response Latency.

    ERIC Educational Resources Information Center

    Halkitis, Perry N.; And Others

    The relationship between test item characteristics and testing time was studied for a computer-administered licensing examination. One objective of the study was to develop a model to predict testing time on the basis of known item characteristics. Response latencies (i.e., the amount of time taken by examinees to read, review, and answer items)…

  7. Spectral characteristics of time resolved magnonic spin Seebeck effect

    NASA Astrophysics Data System (ADS)

    Etesami, S. R.; Chotorlishvili, L.; Berakdar, J.

    2015-09-01

    Spin Seebeck effect (SSE) holds promise for new spintronic devices with low-energy consumption. The underlying physics, essential for a further progress, is yet to be fully clarified. This study of the time resolved longitudinal SSE in the magnetic insulator yttrium iron garnet concludes that a substantial contribution to the spin current stems from small wave-vector subthermal exchange magnons. Our finding is in line with the recent experiment by S. R. Boona and J. P. Heremans [Phys. Rev. B 90, 064421 (2014)]. Technically, the spin-current dynamics is treated based on the Landau-Lifshitz-Gilbert equation also including magnons back-action on thermal bath, while the formation of the time dependent thermal gradient is described self-consistently via the heat equation coupled to the magnetization dynamics.

  8. Characteristics of oscillating magnetic field-actuated microvalve response time

    NASA Astrophysics Data System (ADS)

    Kessler, Jonathan; Ghosh, Santaneel; Peng, Jian; Schenk, Clayton

    2010-03-01

    Magnetically responsive thermo-active hydrogels offer several potential advantages over other bio-material systems for the controlled release applications for micro- and nanofluidic devices. Volume phase transition of the thermo-sensitive gels is controlled by the change in entropy of the system induced by the hysteresis loss of embedded ferromagnetic nanoparticles modulated by an ac magnetic field. It has been shown in [1], a poly(N-isopropylacrylamide) (PNIPAM) based thermo-responsive system provides controlled heating and volumetric changes with a significantly faster response time through magnetic actuation owing to its smaller dimension. Moreover, it is extremely easy to modulate the field and frequency. Varying the flow rate, channel diameter, and valve width, we characterize the response time of the microvalve for drug delivery applications. [1] S. Ghosh, C. Yang, T. Cai, Z. Hu, and A. Neogi, J. Phys. D: Appl. Phys. 42 (2009) 135501

  9. Relaxation Characteristics of 828 DGEBA Epoxy Over Long Time Periods

    NASA Astrophysics Data System (ADS)

    Hoo, Jasmine; Reprogle, Riley C.; Wisler, Brian; Arechederra, Gabriel K.; McCoy, John D.; Kropka, Jamie M.; Long, Kevin N.

    The mechanical relaxation response in uniaxial compression of a diglycidyl ether of bisphenol-A epoxy was studied over long time periods. The epoxy, 828DEA, was Epon 828 cured with diethanolamine (DEA). A sample was compressed at constant strain rate and held at various strain levels for days to allow the sample to relax. The sample was then compressed further and held once more. The relaxation curves were fit with a stretched exponential function. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  10. Inverting Source Time Functions to determine the fault kinematic characteristics

    NASA Astrophysics Data System (ADS)

    Toraldo Serra, E. M.; Orefice, A.; Emolo, A.; Zollo, A.

    2012-04-01

    In seismology, the analisys of source kinematic parameters (slip-rate and rupture velocity ecc.) is a fundamental way to study the time-history of the rupture process that occurs during a seismic event. To this end various method to reconstruct source kinematics models from the inversion of seismogram have been proposed during the time. In this work we present an alternative methodology to infer source models. We aim, indeed, at obtaining the slip and rupture velocity distribution on the fault plane inverting the apparent Source Time Functions (STFs). This kind of analysis, rather than a classical inversion based on a direct study of seismograms recorded at various stations, may have several advantages. A major advantage is related to the possibility to overcome in the forward modeling any problem related to the computation of the Green's function, as the choice of the correct and reliable propagation model. To retrieve reliable STF, we apply the stabilized deconvolution technique proposed by Vallée [2004]. Based on Empirical Green's Functions (EGF) approach, this technique integrates in the deconvolution process four physical constraints on the STFs, that are causality, positivity, limited duration, and equal area. In any case the EGF approach suffers from certain limitations related to the selection of valuable Empirical Green Function, especially for small events. The approach used to invert the STFs is based on the technique of Emolo and Zollo [2005] to invert strong-motion data. In particular, the slip and the rupture velocity values are specified only at a set of control-points on the fault plane and their distributions on the whole fault are then obtained by a bicubic interpolation. The final slip and rupture velocity values at the fault-grid nodes are then determined by searching for the maximum of a fitness function (based of comparison between real and synthetic STFs) by using the Genetic Algorithm. The number of control-points is progressively increased to move from a high- to low-wavelength description of kinematic parameters on the fault. The optimal model parameter set is chosen according to Akaike Information Criterion [1974]. We present results for some synthetic tests and an application to a seismic events occurred during the 2009 L'Aquila (Central Italy) seismic sequence. In particular, we analyzed a small aftershock occurred on 2009 April 9, at 04:43:09 (UTC) characterized by a seismic moment of 1.07e+15 Nm (Mw 4). We found: a slip distribution, with an average value of 0.8 cm, characterized by a main slip patch located NW of the hypocenter and a rupture velocity distribution (mean value of 2.3 km/s) with a strong acceleration in the same direction.

  11. Characteristic time for halo current growth and rotation

    SciTech Connect

    Boozer, Allen H.

    2015-10-15

    A halo current flows for part of its path through the plasma edge and for part through the chamber walls and during tokamak disruptions can be as large as tenths of the plasma current. The primary interest in halo currents is the large force that they can exert on machine components particularly if the toriodal rotation of the halo current resonates with a natural oscillation frequency of the tokamak device. Halo currents arise when required to slow down the growth of a kink that is too unstable to be stabilized by the chamber walls. The width of the current channel in the halo plasma is comparable to the amplitude of the kink, and the halo current grows linearly, not exponentially, in time. The current density in the halo is comparable to that of the main plasma body. The rocket force due to plasma flowing out of the halo and recombining on the chamber walls can cause the non-axisymmetric magnetic structure produced by the kink to rotate toroidally at a speed comparable to the halo speed of sound. Gerhardt's observations of the halo current in NSTX shot 141 687 [Nucl. Fusion 53, 023005 (2013)] illustrate many features of the theory of halo currents and are discussed as a summary of the theory.

  12. Timing and distance characteristics of interpersonal coordination during locomotion.

    PubMed

    Ducourant, Thomas; Vieilledent, Stphane; Kerlirzin, Yves; Berthoz, Alain

    2005-11-25

    Most studies about human locomotion only tend to consider single subjects walking alone in a stationary environment. Nevertheless, human subjects have often to plan and generate their locomotor trajectories according to one another's displacements. Therefore, in the present study we address the question of the interpersonal coordination when pairs of subjects walk simultaneously. Six pairs of subjects walking face to face, backwards and forwards on a 8 m x 2 m track were involved in our experiment. Within each pair, the leader (L) was required to break the initial interpersonal distance whereas the follower (F) had to maintain this distance constant (1, 2 or 3 m). We measured their position and analyzed their travelled distance, the time course of their linear displacement, and the kinematics parameters of their steps. Our results show that F travels smaller distances than L and that even if they are highly correlated, some temporal delays exist between displacements of L and F with greater values when the interpersonal distance increases (from 1 to 3 m). These results are discussed in terms of high level imitation, i.e. bidirectional interactions with mutual influences of each subject on one another. PMID:16095821

  13. Characteristic time for halo current growth and rotation

    NASA Astrophysics Data System (ADS)

    Boozer, Allen H.

    2015-10-01

    A halo current flows for part of its path through the plasma edge and for part through the chamber walls and during tokamak disruptions can be as large as tenths of the plasma current. The primary interest in halo currents is the large force that they can exert on machine components particularly if the toriodal rotation of the halo current resonates with a natural oscillation frequency of the tokamak device. Halo currents arise when required to slow down the growth of a kink that is too unstable to be stabilized by the chamber walls. The width of the current channel in the halo plasma is comparable to the amplitude of the kink, and the halo current grows linearly, not exponentially, in time. The current density in the halo is comparable to that of the main plasma body. The rocket force due to plasma flowing out of the halo and recombining on the chamber walls can cause the non-axisymmetric magnetic structure produced by the kink to rotate toroidally at a speed comparable to the halo speed of sound. Gerhardt's observations of the halo current in NSTX shot 141 687 [Nucl. Fusion 53, 023005 (2013)] illustrate many features of the theory of halo currents and are discussed as a summary of the theory.

  14. The Impact of Item Format and Examinee Characteristics on Response Times

    ERIC Educational Resources Information Center

    Hess, Brian J.; Johnston, Mary M.; Lipner, Rebecca S.

    2013-01-01

    Current research on examination response time has focused on tests comprised of traditional multiple-choice items. Consequently, the impact of other innovative or complex item formats on examinee response time is not understood. The present study used multilevel growth modeling to investigate examinee characteristics associated with response time…

  15. Time-current characteristics and minimum fusing current of R-113 on a horizontal wire

    SciTech Connect

    Fujii, M.; Ikeuchi, M. )

    1991-01-01

    This paper reports on an experimental and analytical investigation to determine the time-current characteristics and the minimum fusing current for a horizontal submerged metallic (Cu, Pb) wire, undergoing a step in Joule heating applied by ac current leading to boiling on its surface. The experiment were performed using R-113 at atmospheric pressure with a pool temperature of about 30K subcooled, and also in air. The time-current characteristic with boiling had a steep slope, and the minimum fusing current was very large compared to that obtained in air. The fusion of the wire with boiling was a physical burn-out phenomenon, and the time to interruption was in the region of film boiling. The time-current characteristics were simulated for various wires by using a thermal network.

  16. Volt-time characteristics of short air gaps under nonstandard lightning voltage waves

    SciTech Connect

    Chowdhuri, P.; Mishra, A.K.; McConnell, B.W.

    1996-02-01

    The breakdown voltage level of a dielectric system under a transient voltage of a given waveshape is not a constant parameter. When transient voltages of the same waveshape but of increasing amplitude are applied to a dielectric system, the dielectric breaks down at higher voltage levels at shorter time delays for the higher applied voltages. This characteristic, known as the volt-time or time-lag characteristic, significantly influences the insulation coordination of an electric power system. The volt-time characteristics of 5-cm long rod-plane and rod-rod air gaps were experimentally determined with five different waveshapes of the applied impulse voltage. The front time of the waves was varied from 25 ns to 10 {micro}s, and the time to half value was varied from 0.5 {micro}s to 100 {micro}s. The volt-time characteristics were also checked analytically using the concept of disruptive effect. The parameters for the disruptive effect were experimentally determined.

  17. Electrical probe characteristic recovery by measuring only one time-dependent parameter

    NASA Astrophysics Data System (ADS)

    Costin, C.; Popa, G.; Anita, V.

    2016-03-01

    Two straightforward methods for recovering the current-voltage characteristic of an electrical probe are proposed. Basically, they consist of replacing the usual power supply from the probe circuit with a capacitor which can be charged or discharged by the probe current drained from the plasma. The experiment requires the registration of only one time-dependent electrical parameter, either the probe current or the probe voltage. The corresponding time-dependence of the second parameter, the probe voltage, or the probe current, respectively, can be calculated using an integral or a differential relation and the current-voltage characteristic of the probe can be obtained.

  18. Characteristic time scales in the American dollar-Mexican peso exchange currency market

    NASA Astrophysics Data System (ADS)

    Alvarez-Ramirez, Jose

    2002-06-01

    Daily fluctuations of the American dollar-Mexican peso exchange currency market are studied using multifractal analysis methods. It is found evidence of multiaffinity of daily fluctuations in the sense that the qth-order (roughness) Hurst exponent Hq varies with changes in q. It is also found that there exist several characteristic time scales ranging from week to year. Accordingly, the market exhibits persistence in the sense that instabilities introduced by market events acting around the characteristic time scales (mainly, quarter and year) would propagate through the future market activity. Some implications of our results on the regulation of the dollar-mexpeso market activity are discussed.

  19. [The Time Sequence Noise Characteristics of the X- ray Fluoroscopic Image].

    PubMed

    Umehara, Takayoshi; Matsumoto, Kazuma; Fujita, Tomoko; Maeda, Katsuhiko; Ikeuchi, Youko; Hagihara, Yoshiaki; Fujikawa, Keita

    2016-01-01

    The role of the X-ray fluoroscopic image during interventional radiology (IVR) is not only the real-time dynamic image for the catheter operation but also to confirm the vascular anatomy using stored image, so that the importance increases more. For the purpose of measuring the time sequence characteristics of X-ray fluoroscopic image, we sampled the digital value of the same coordinate from each X-ray fluoroscopic image and calculated the frequency properties of the noise for the time sequence order as NPStime by performing Fourier transform on the digital value. The parameters, except k-factor which is the time sequence filter, did not influence NPStime. NPStime, which was examined in this study, showed that it is valuable for the method to analyze the time sequence noise characteristics. And, it also showed that it is possible to evaluate the time sequence image processing parameters of X-ray fluoroscopic image by NPStime. Nowadays, each manufacture of the X-ray angiographic system performs the original image processing to their own X-ray fluoroscopic images. The results of the discussion in this study could show the quantitative analysis on the frequency modulation. And it is possible to calculate NPStime by measuring the digital value of stored X-ray fluoroscopic image. The analysis by this method is also technically convenient for the time sequence noise characteristics of the X-ray fluoroscopic image. PMID:26796929

  20. Predicting permeability from the characteristic relaxation time and intrinsic formation factor of complex conductivity spectra

    NASA Astrophysics Data System (ADS)

    Revil, A.; Binley, A.; Mejus, L.; Kessouri, P.

    2015-08-01

    Low-frequency quadrature conductivity spectra of siliclastic materials exhibit typically a characteristic relaxation time, which either corresponds to the peak frequency of the phase or the quadrature conductivity or a typical corner frequency, at which the quadrature conductivity starts to decrease rapidly toward lower frequencies. This characteristic relaxation time can be combined with the (intrinsic) formation factor and a diffusion coefficient to predict the permeability to flow of porous materials at saturation. The intrinsic formation factor can either be determined at several salinities using an electrical conductivity model or at a single salinity using a relationship between the surface and quadrature conductivities. The diffusion coefficient entering into the relationship between the permeability, the characteristic relaxation time, and the formation factor takes only two distinct values for isothermal conditions. For pure silica, the diffusion coefficient of cations, like sodium or potassium, in the Stern layer is equal to the diffusion coefficient of these ions in the bulk pore water, indicating weak sorption of these couterions. For clayey materials and clean sands and sandstones whose surface have been exposed to alumina (possibly iron), the diffusion coefficient of the cations in the Stern layer appears to be 350 times smaller than the diffusion coefficient of the same cations in the pore water. These values are consistent with the values of the ionic mobilities used to determine the amplitude of the low and high-frequency quadrature conductivities and surface conductivity. The database used to test the model comprises a total of 202 samples. Our analysis reveals that permeability prediction with the proposed model is usually within an order of magnitude from the measured value above 0.1 mD. We also discuss the relationship between the different time constants that have been considered in previous works as characteristic relaxation time, including the mean relaxation time obtained from a Debye decomposition of the spectra and the Cole-Cole time constant.

  1. The Family as Portrayed on Prime-Time Television, 1947-1990: Structure and Characteristics.

    ERIC Educational Resources Information Center

    Moore, Marvin L.

    1992-01-01

    Examines 115 successful television series portraying white and African-American families across 4 decades of U.S. prime-time television for the structure and characteristics of the families. The data show a trend toward more equal presentation of conventional and nonconventional families, few divorced or female single parents, and few minority…

  2. The Camberwell Cohort 25 Years On: Characteristics and Changes in Skills over Time

    ERIC Educational Resources Information Center

    Beadle-Brown, Julie; Murphy, Glynis; Wing, Lorna

    2006-01-01

    Background: This study presents data on the characteristics of the Camberwell Cohort, 25 years after they were first assessed in the 1970s [Wing & Gould (1979) "Journal of Autism and Childhood Schizophrenia" vol. 9, pp. 11-29]. It also presents data on changes over time which adds to that presented in Beadle-Brown et al. ["Journal of Intellectual…

  3. Curriculum Characteristics of Time-Compressed Course in a U.S. Higher Education Institution

    ERIC Educational Resources Information Center

    Hyun, Eunsook; Kretovics, Mark; Crowe, Alicia

    2006-01-01

    The study explored characteristics of the curriculum practice of higher education faculty in the context of time-compressed (e.g., 5-6 weeks) courses as compared with regular term (15-16 weeks) courses. The researchers used open-ended questions on a web-based survey at a large doctoral-extensive university in a Midwestern state in the United…

  4. Characteristics of the transmission of autoregressive sub-patterns in financial time series.

    PubMed

    Gao, Xiangyun; An, Haizhong; Fang, Wei; Huang, Xuan; Li, Huajiao; Zhong, Weiqiong

    2014-01-01

    There are many types of autoregressive patterns in financial time series, and they form a transmission process. Here, we define autoregressive patterns quantitatively through an econometrical regression model. We present a computational algorithm that sets the autoregressive patterns as nodes and transmissions between patterns as edges, and then converts the transmission process of autoregressive patterns in a time series into a network. We utilised daily Shanghai (securities) composite index time series to study the transmission characteristics of autoregressive patterns. We found statistically significant evidence that the financial market is not random and that there are similar characteristics between parts and whole time series. A few types of autoregressive sub-patterns and transmission patterns drive the oscillations of the financial market. A clustering effect on fluctuations appears in the transmission process, and certain non-major autoregressive sub-patterns have high media capabilities in the financial time series. Different stock indexes exhibit similar characteristics in the transmission of fluctuation information. This work not only proposes a distinctive perspective for analysing financial time series but also provides important information for investors. PMID:25189200

  5. Characteristics of the transmission of autoregressive sub-patterns in financial time series

    PubMed Central

    Gao, Xiangyun; An, Haizhong; Fang, Wei; Huang, Xuan; Li, Huajiao; Zhong, Weiqiong

    2014-01-01

    There are many types of autoregressive patterns in financial time series, and they form a transmission process. Here, we define autoregressive patterns quantitatively through an econometrical regression model. We present a computational algorithm that sets the autoregressive patterns as nodes and transmissions between patterns as edges, and then converts the transmission process of autoregressive patterns in a time series into a network. We utilised daily Shanghai (securities) composite index time series to study the transmission characteristics of autoregressive patterns. We found statistically significant evidence that the financial market is not random and that there are similar characteristics between parts and whole time series. A few types of autoregressive sub-patterns and transmission patterns drive the oscillations of the financial market. A clustering effect on fluctuations appears in the transmission process, and certain non-major autoregressive sub-patterns have high media capabilities in the financial time series. Different stock indexes exhibit similar characteristics in the transmission of fluctuation information. This work not only proposes a distinctive perspective for analysing financial time series but also provides important information for investors. PMID:25189200

  6. The Dependence of Characteristic Times of Gradual SEP Events on Their Associated CME Properties

    NASA Astrophysics Data System (ADS)

    Pan, Z. H.; Wang, C. B.; Xue, X. H.; Wang, Y. M.

    It is generally believed that coronal mass ejections CMEs are the drivers of shocks that accelerate gradual solar energetic particles SEPs One might expect that the characteristics of the SEP intensity time profiles observed at 1 AU are determined by properties of the associated CMEs such as the radial speed and the angular width Recently Kahler statistically investigated the characteristic times of gradual SEP events observed from 1998-2002 and their associated coronal mass ejection properties Astrophys J 628 1014--1022 2005 Three characteristic times of gradual SEP events are determined as functions of solar source longitude 1 T 0 the time from associated CME launch to SEP onset at 1 AU 2 T R the rise time from SEP onset to the time when the SEP intensity is a factor of 2 below peak intensity and 3 T D the duration over which the SEP intensity is within a factor of 2 of the peak intensity However in his study the CME speeds and angular widths are directly taken from the LASCO CME catalog In this study we analyze the radial speeds and the angular widths of CMEs by an ice-cream cone model and re-investigate their correlationships with the characteristic times of the corresponding SEP events We find T R and T D are significantly correlated with radial speed for SEP events in the best-connected longitude range and there is no correlation between T 0 and CME radial speed and angular width which is consistent with Kahler s results On the other hand it s found that T R and T D are also have

  7. Delay-correlation landscape reveals characteristic time delays of brain rhythms and heart interactions.

    PubMed

    Lin, Aijing; Liu, Kang K L; Bartsch, Ronny P; Ivanov, Plamen Ch

    2016-05-13

    Within the framework of 'Network Physiology', we ask a fundamental question of how modulations in cardiac dynamics emerge from networked brain-heart interactions. We propose a generalized time-delay approach to identify and quantify dynamical interactions between physiologically relevant brain rhythms and the heart rate. We perform empirical analysis of synchronized continuous EEG and ECG recordings from 34 healthy subjects during night-time sleep. For each pair of brain rhythm and heart interaction, we construct a delay-correlation landscape (DCL) that characterizes how individual brain rhythms are coupled to the heart rate, and how modulations in brain and cardiac dynamics are coordinated in time. We uncover characteristic time delays and an ensemble of specific profiles for the probability distribution of time delays that underly brain-heart interactions. These profiles are consistently observed in all subjects, indicating a universal pattern. Tracking the evolution of DCL across different sleep stages, we find that the ensemble of time-delay profiles changes from one physiologic state to another, indicating a strong association with physiologic state and function. The reported observations provide new insights on neurophysiological regulation of cardiac dynamics, with potential for broad clinical applications. The presented approach allows one to simultaneously capture key elements of dynamic interactions, including characteristic time delays and their time evolution, and can be applied to a range of coupled dynamical systems. PMID:27044991

  8. Learning characteristics of a space-time neural network as a tether skiprope observer

    NASA Technical Reports Server (NTRS)

    Lea, Robert N.; Villarreal, James A.; Jani, Yashvant; Copeland, Charles

    1992-01-01

    The Software Technology Laboratory at JSC is testing a Space Time Neural Network (STNN) for observing tether oscillations present during retrieval of a tethered satellite. Proper identification of tether oscillations, known as 'skiprope' motion, is vital to safe retrieval of the tethered satellite. Our studies indicate that STNN has certain learning characteristics that must be understood properly to utilize this type of neural network for the tethered satellite problem. We present our findings on the learning characteristics including a learning rate versus momentum performance table.

  9. Learning characteristics of a space-time neural network as a tether skiprope observer

    NASA Technical Reports Server (NTRS)

    Lea, Robert N.; Villarreal, James A.; Jani, Yashvant; Copeland, Charles

    1993-01-01

    The Software Technology Laboratory at the Johnson Space Center is testing a Space Time Neural Network (STNN) for observing tether oscillations present during retrieval of a tethered satellite. Proper identification of tether oscillations, known as 'skiprope' motion, is vital to safe retrieval of the tethered satellite. Our studies indicate that STNN has certain learning characteristics that must be understood properly to utilize this type of neural network for the tethered satellite problem. We present our findings on the learning characteristics including a learning rate versus momentum performance table.

  10. In situ real-time measurement of physical characteristics of airborne bacterial particles

    NASA Astrophysics Data System (ADS)

    Jung, Jae Hee; Lee, Jung Eun

    2013-12-01

    Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

  11. Characteristic times in the English Channel from numerical modelling: supporting decision-making.

    PubMed

    Periáñez, R; Miró, C

    2009-06-01

    A numerical model that simulates the dispersion of radionuclides in the English Channel has been applied to study the dispersion of conservative and non-conservative radionuclides released from the La Hague nuclear fuel reprocessing plant. The model is based upon previous work and now is able to simulate dispersion over long timescales (decades), explicitly including transport by instantaneous tidal currents and variable wind conditions. Wind conditions are obtained from meteorological statistics using a stochastic method. Outputs from the model are treated using time-series analysis techniques. These techniques allow the determination of characteristic times of the system, transport velocities and dispersion factors. This information may be very useful to support the decision-making process after an emergency situation. Thus, we are proposing that time-series analysis can be integrated with numerical modelling for helping decision-making in response to an accident. The model is first validated through its application to actual releases of 99Tc and 125Sb, comparing measured and computed concentrations, and characteristic times for three radionuclides are given next: a perfectly conservative one, a very reactive one ((239,240)Pu) and 137Cs, which has an intermediate behaviour. Characteristic transport velocities and dispersion factors have been calculated as well. Model results are supported by experimental evidence. PMID:19454798

  12. Time-Varying Multifractal Characteristics and Formation Mechanism of Loaded Coal Electromagnetic Radiation

    NASA Astrophysics Data System (ADS)

    Hu, Shaobin; Wang, Enyuan; Li, Zhonghui; Shen, Rongxi; Liu, Jie

    2014-09-01

    Dynamic collapses of deeply mined coal rocks are severe threats to miners. To predict the collapses more accurately using electromagnetic radiation (EMR), we investigate the time-varying multifractal characteristics and formation mechanism of EMR induced by underground coal mining. A series of uniaxial compression and multi-stage loading experiments with coal samples of different mechanical properties were carried out. The EMR signals during their damage evolution were monitored in real-time; the inherent law of EMR time series was analyzed by fractal theory. The results show that the time-varying multifractal characteristics of EMR are determined by damage evolutions process, the dissipated energy caused by damage evolutions such as crack propagation, fractal sliding and shearing can be regard as the fingerprint of various EMR micro-mechanics. Based on the Irreversible thermodynamics and damage mechanics, we introduced the damage internal variable, constructed the dissipative potential function and established the coupled model of the EMR and the dissipative energy, which revealed the nature of dynamic nonlinear characteristics of EMR. Dynamic multifractal spectrum is the objective response of EMR signals, thus it can be used to evaluate the coal deformation and fracture process.

  13. Characteristic times in the nanometer-picosecond translational collective dynamics of molecular liquids.

    PubMed

    Bafile, Ubaldo; Guarini, Eleonora; Sampoli, Marco; Barocchi, Fabrizio

    2009-10-01

    Molecular-dynamics calculations of the translational dynamic structure factor in liquid CO2 and CD4 are analyzed by means of the generalized Langevin equation for the intermediate scattering function in the second-order memory function approximation. We give a rigorous general relation among the decay times of the memory and the lifetimes of the modes of the density-density correlation function. The comparison of the various characteristic times among them and with the collision time, carried out as a function of the wave vector, reveals strong relationships between the memory relaxation and the density-density correlation modes, some of which have purely "collisional" and other "collective" character. We show that essential information about the life time of structural properties in a molecular liquid at nanometer dimensions can be obtained if the time behavior of the correlation function is considered in addition to that of the memory function. PMID:19905262

  14. Characteristic times in the nanometer-picosecond translational collective dynamics of molecular liquids

    NASA Astrophysics Data System (ADS)

    Bafile, Ubaldo; Guarini, Eleonora; Sampoli, Marco; Barocchi, Fabrizio

    2009-10-01

    Molecular-dynamics calculations of the translational dynamic structure factor in liquid CO2 and CD4 are analyzed by means of the generalized Langevin equation for the intermediate scattering function in the second-order memory function approximation. We give a rigorous general relation among the decay times of the memory and the lifetimes of the modes of the density-density correlation function. The comparison of the various characteristic times among them and with the collision time, carried out as a function of the wave vector, reveals strong relationships between the memory relaxation and the density-density correlation modes, some of which have purely collisional and other collective character. We show that essential information about the life time of structural properties in a molecular liquid at nanometer dimensions can be obtained if the time behavior of the correlation function is considered in addition to that of the memory function.

  15. Time resolving characteristics of HPK and FBK silicon photomultipliers for TOF and PET applications

    NASA Astrophysics Data System (ADS)

    Ambrosi, G.; Azzarello, P.; Battiston, R.; Di Lorenzo, G.; Ionica, M.; Pignatel, G. U.; Piemonte, C.; Dalla Betta, G.-F.; Del Guerra, A.

    2010-05-01

    In time-of-flight measurements, or positron emission tomography experiments where two gamma rays are detected in coincidence, the time resolution of the photodetector is of primary importance. SiPMs are very promising devices for these applications, since their intrinsic response time can be less than 1 ns. However the actual timing resolution of SiPM is affected by the area (capacitance) of the device, by the type of used to pre-amplify the signal, by the dark count rate which is revealed as pure noise, and other second order effects like cross-talk and after pulsing. In this work we report the characteristics of different samples of Hamamatsu Photonics (HPK) and Fondazione Bruno Kessler (FBK) SiPM, with pixel size ranging from 40 to 100 μm. In particular, we have investigated their time response when stimulated with O(50) ps pulsed laser at wavelengths in the range 400-800 nm.

  16. Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization

    SciTech Connect

    Advani, S.H.; Lee, T.S. ); Moon, H. )

    1992-10-01

    The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracture toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.

  17. Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization. Final report

    SciTech Connect

    Advani, S.H.; Lee, T.S.; Moon, H.

    1992-10-01

    The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracture toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.

  18. Effect of mixing time on the structural characteristics of noodle dough under vacuum.

    PubMed

    Liu, Rui; Xing, Yanan; Zhang, Yingquan; Zhang, Bo; Jiang, Xuju; Wei, Yimin

    2015-12-01

    The structural characteristics of noodle dough under different vacuum mixing times were investigated using three flour samples by texture profile analysis (TPA), SEM, FTIR micro-imaging, and by measuring the glutenin macropolymer and free -SH content. The sheeted dough mixed for 8 min presented better textural properties and a more compact and even microstructure. Insufficient mixing resulted in an uneven distribution and an inadequately developed gluten network, especially for weak-gluten flour (Jimai 22). Excessive mixing was detrimental to the developed dough network and decreased the uniformity of component spatial distribution. Furthermore, excessive mixing led to a decrease in GMP content as well as the increase in free -SH content. Flours with different protein characteristics behaved differently. The TPA, microstructure and free -SH content of dough of Zhengmai 366 was less affected by mixing time than that of Jimai 22, suggesting that strong-gluten flour has better noodle dough mixing tolerance. PMID:26041200

  19. Sociodemographic Characteristics and Waking Activities and their Role in the Timing and Duration of Sleep

    PubMed Central

    Basner, Mathias; Spaeth, Andrea M.; Dinges, David F.

    2014-01-01

    Study Objectives: Chronic sleep restriction is prevalent in the U.S. population and associated with increased morbidity and mortality. The primary reasons for reduced sleep are unknown. Using population data on time use, we sought to identify individual characteristics and behaviors associated with short sleep that could be targeted for intervention programs. Design: Analysis of the American Time Use Survey (ATUS). Setting: Cross-sectional annual survey conducted by the U.S. Bureau of Labor Statistics. Participants: Representative cohort (N = 124,517) of Americans 15 years and older surveyed between 2003 and 2011. Interventions: None. Measurements and Results: Telephone survey of activities over 24 hours. Relative to all other waking activities, paid work time was the primary waking activity exchanged for sleep. Time spent traveling, which included commuting to/from work, and immediate pre- and post-sleep activities (socializing, grooming, watching TV) were also reciprocally related to sleep duration. With every hour that work or educational training started later in the morning, sleep time increased by approximately 20 minutes. Working multiple jobs was associated with the highest odds for sleeping ≤ 6 hours on weekdays (adjusted OR 1.61, 95% CI 1.44; 1.81). Self-employed respondents were less likely to be short sleepers compared to private sector employees (OR 0.83, 95% CI 0.72; 0.95). Sociodemographic characteristics associated with paid work (age 25-64, male sex, high income, and employment per se) were consistently associated with short sleep. Conclusions: U.S. population time use survey findings suggest that interventions to increase sleep time should concentrate on delaying the morning start time of work and educational activities (or making them more flexible), increasing sleep opportunities, and shortening morning and evening commute times. Reducing the need for multiple jobs may increase sleep time, but economic disincentives from working fewer hours will need to be offset. Raising awareness of the importance of sufficient sleep for health and safety may be necessary to positively influence discretionary behaviors that reduce sleep time, including television viewing and morning grooming. Citation: Basner M, Spaeth AM, Dinges DF. Sociodemographic characteristics and waking activities and their role in the timing and duration of sleep. SLEEP 2014;37(12):1889-1906. PMID:25325472

  20. Investigation of time characteristics of photodetectors based on Ge/Si nanoheterostructures

    NASA Astrophysics Data System (ADS)

    Donchenko, V. A.; Yakimov, A. I.; Zemlyanov, A. A.; Kirienko, V. V.

    2010-10-01

    Results of investigations into the time characteristics of photosensitive layers based on Ge/Si nanoheterostructures excited by femtosecond laser pulses with a wavelength of 1.55 μm are given. It is demonstrated that the leading front duration of the photoresponse pulse for the examined specimens excited by laser pulses of 120 fs duration does not exceed 30-40 пs.

  1. Program and Teacher Characteristics Predicting the Implementation of Banking Time with Preschoolers Who Display Disruptive Behaviors.

    PubMed

    Williford, Amanda P; Wolcott, Catherine Sanger; Whittaker, Jessica Vick; Locasale-Crouch, Jennifer

    2015-11-01

    This study examined the relationship among baseline program and teacher characteristics and subsequent implementation of Banking Time. Banking Time is a dyadic intervention intended to improve a teacher's interaction quality with a specific child. Banking Time implementation was examined in the current study using a sample of 59 teachers and preschool children displaying disruptive behaviors in the classroom (~three children per classroom). Predictors included preschool program type, teacher demographic characteristics (personal and professional), and teacher beliefs (self-efficacy, authoritarian beliefs, and negative attributions about child disruptive behavior). Multiple measures and methods (i.e., teacher report, consultant report, independent observations) were used to assess implementation. We created three implementation composite measures (dosage, quality, and generalized practice) that had high internal consistencies within each composite but were only modestly associated with one another, suggesting unique constructs of implementation. We found that type of preschool program was associated with dosage and quality. Aspects of teacher demographics related to all three implementation composites. Teacher beliefs predicted dosage and generalized practice. Results suggest that the factors that predict the implementation of Banking Time vary as a function of the type of implementation being assessed. PMID:25627344

  2. Error propagation in time-dependent probability of occurrence for characteristic earthquakes in Italy

    NASA Astrophysics Data System (ADS)

    Peruzza, Laura; Pace, Bruno; Cavallini, Fabio

    2010-01-01

    Time-dependent models for seismic hazard and earthquake probabilities are at the leading edge of research nowadays. In the framework of a 2-year national Italian project (2005-2007), we have applied the Brownian passage time (BPT) renewal model to the recently released Database of Individual Seismogenic Sources (DISS) to compute earthquake probability in the period 2007-2036. Observed interevent times on faults in Italy are absolutely insufficient to characterize the recurrence time. We, therefore, derived mean recurrence intervals indirectly. To estimate the uncertainty of the results, we resorted to the theory of error propagation with respect to the main parameters: magnitude and slip rate. The main issue concerned the high variability of slip rate, which could hardly be reduced by exploiting geodetic constraints. We did some validation tests, and interesting considerations were derived from seismic moment budgeting on the historical earthquake catalog. In a time-dependent perspective, i.e., when the date of the last event is known, only 10-15% of the 115 sources exhibit a probability of a characteristic earthquake in the next 30 years higher than the equivalent Poissonian probabilities. If we accept the Japanese conventional choice of probability threshold greater than 3% in 30 years to define highly probable sources, mainly intermediate earthquake faults with characteristic M < 6, having an elapsed time of 0.7-1.2 times the recurrence interval are the most prone sources. The number of highly probable sources rises by increasing the aperiodicity coefficient (from 14 sources in the case of variable ? ranging between 0.22 and 0.36 to 31 sources out of 115 in the case of an ? value fixed at 0.7). On the other hand, in stationary time-independent approaches, more than two thirds of all sources are considered probabilistically prone to an impending earthquake. The performed tests show the influence of the variability of the aperiodicity factor in the BPT renewal model on the absolute probability values. However, the influence on the relative ranking of sources is small. Future developments should give priority to a more accurate determination of the date of the last seismic event for a few seismogenic sources of the DISS catalog and to a careful check on the applicability of a purely characteristic model.

  3. Adults’ reports of their earliest memories: Consistency in events, ages, and narrative characteristics over time

    PubMed Central

    Bauer, Patricia J.; Tasdemir-Ozdes, Aylin; Larkina, Marina

    2014-01-01

    Earliest memories have been of interest since the late 1800s, when it was first noted that most adults do not have memories from the first years of life (so-called childhood amnesia). Several characteristics of adults’ earliest memories have been investigated, including emotional content, the perspective from which they are recalled, and vividness. The focus of the present research was a feature of early memories heretofore relatively neglected in the literature, namely, their consistency. Adults reported their earliest memories 2 to 4 times over a 4-year period. Reports of earliest memories were highly consistent in the events identified as the bases for earliest memories, the reported age at the time of the event, and in terms of qualities of the narrative descriptions. These findings imply stability in the boundary that marks the offset of childhood amnesia, as well as in the beginning of a continuous sense of self over time. PMID:24836979

  4. Characteristic Evaluation of Synchronous Motors Using an Universal Drive System with a Real-Time Interface

    NASA Astrophysics Data System (ADS)

    Amano, Yoko; Ogasawara, Satoshi

    In this paper, a new universal drive system of synchronous motors used Real-Time Interface (RTI) performs characteristic evaluation of Synchronous Reluctance (SynR) motors and Surface Permanent Magnet (SPM) synchronous motors. The RTI connects directly a simulation model with experimental equipment, and makes it possible to use the simulation model for an experiment. The RTI is very effective in the early detection of an actual problem and examination of solution technique. Moreover, it concentrates on examination of control algorithm, and efficient research and development are enabled. A measuring system of synchronous motors is built by the universal drive system. The examination of various synchronous motors is possible for the measurement system using the same control algorithm. Characteristic evaluation of a SynR motor and a SPM synchronous motor that are the same gap length and stator was performed using the measuring system. The measurement result shows experimentally that motor loss of the SynR motor is smaller rather than the SPM synchronous motor, at the time of high speed and low load operation. For example, the SynR motor is suitable to hybrid cars with the comparatively long time of low load and high-speed operation.

  5. An analysis of multifractal characteristics of API time series in Nanjing, China

    NASA Astrophysics Data System (ADS)

    Shen, Chen-hua; Huang, Yi; Yan, Ya-ni

    2016-06-01

    This paper describes multifractal characteristics of daily air pollution index (API) records in Nanjing from 2001 to 2012. The entire daily API time series is first divided into 12 parts that serve as research objects, and the generalized Hurst exponent is calculated for each series. And then, the multifractal sources are analyzed and singularity spectra are shown. Next, based on a singularity spectrum, the multifractal-characteristics parameters (maximum exponent α0, spectrum width Δ α, and asymmetry Δ αas) are introduced. The results show that the fractality of daily API for each year is multifractal. The multifractal sources originate from both a broad probability density function and different long-range correlations with small and large fluctuations. The strength of the distribution multifractality is stronger than that of the correlation multifractality. The variation in the structure of API time series with increasing years is mainly related to long-range correlations. The structure of API time series in some years is richer. These findings can provide a scientific basis for further probing into the complexity of API.

  6. Flow visualization of time-varying structural characteristics of dean vortices in a curved channel

    NASA Astrophysics Data System (ADS)

    Bella, David Wayne

    1988-12-01

    The time varying development and structure of Dean vortices were studied using flow visualization. Observations were made over a range of Dean numbers from 40 to 200 using a transparent channel with mild curvature, 40:1 aspect ratio, and an inner to outer radius ratio of 0.979. Seven flow visualization techniques were tried but only one, a wood burning smoke generator, produced usable results. Different vortex characteristics were observed and documented in sequences of photographs spaced one quarter of a second apart at locations ranging from 85 to 135 degrees from the start of curvature. Evidence is presented that supports the twisting/rocking nature of the flow.

  7. A New Characteristic Function for Fast Time-Reverse Seismic Event Location

    NASA Astrophysics Data System (ADS)

    Hendriyana, Andri; Bauer, Klaus; Weber, Michael; Jaya, Makky; Muksin, Muksin

    2015-04-01

    Microseismicity produced by natural activities is usually characterized by low signal-to-noise ratio and huge amount of data as recording is conducted for a long period of time. Locating microseismic events is preferably carried out using migration-based methods such as time-reverse modeling (TRM). The original TRM is based on backpropagating the wavefield from the receiver down to the source location. Alternatively, we are using a characteristic function (CF) derived from the measured wavefield as input for the TRM. The motivation for such a strategy is to avoid undesired contributions from secondary arrivals which may generate artifacts in the final images. In this presentation, we introduce a new CF as input for TRM method. To obtain this CF, initially we apply kurtosis-based automatic onset detection and convolution with a given wavelet. The convolution with low frequency wavelets allows us to conduct time-reverse modeling using coarser sampling hence it will reduce computing time. We apply the method to locate seismic events measured along an active part of the Sumatra Fault around the Tarutung pull-apart basin (North Sumatra, Indonesia). The results show that seismic events are well-determined since they are concentrated along the Sumatran fault. Internal details of the Tarutung basin structure could be derived. Our results are consistent with those obtained from inversion of manually picked travel time data.

  8. Fractional derivative and time delay damper characteristics in Duffing-van der Pol oscillators

    NASA Astrophysics Data System (ADS)

    Leung, A. Y. T.; Guo, Zhongjin; Yang, H. X.

    2013-10-01

    In this paper, we investigate the damping characteristics of two Duffing-van der Pol oscillators having damping terms described by fractional derivative and time delay respectively. The residue harmonic balance method is presented to find periodic solutions. No small parameter is assumed. Highly accurate limited cycle frequency and amplitude are captured. The results agree well with the numerical solutions for a wide range of parameters. Based on the obtained solutions, the damping effects of these two oscillators are investigated. When the system parameters are identical, the steady state responses and their stability are qualitatively different. The initial approximations are obtained by solving a few harmonic balance equations. They are improved iteratively by solving linear equations of increasing dimension. The second-order solutions accurately exhibit the dynamical phenomena when taking the fractional derivative and time delay as bifurcation parameters respectively. When damping is described by time delay, the stable steady state response is more complex because time delay takes past history into account implicitly. Numerical examples taking time delay and fractional derivative are respectively given for feature extraction and convergence study.

  9. The Periodic Characteristics of Harmonic Measurement Errors with the Initial Sampling Time

    NASA Astrophysics Data System (ADS)

    Zhang, Shaoyong; Xiong, Jiefeng; Song, Shuping; Bai, Chuanzhen; Li, Hongkai

    2016-02-01

    The stability and consistency of harmonic amplitude measurement is very important for power quality analysis and assessment. Some random factors may influence the measurement results in the real world, for example the initial sampling time. In this paper, we put this view a little forward, and prove that the amplitude errors with DFT method change periodically with the initial-sampling time, and DFT method "may" give relatively worse results, with the window which has better characteristics. To mitigate this random influence and to achieve more stable measurement precision, the well known shifting window average DFT, which is based on expectation calculation, is adopted. The effectiveness of this method and its recursive mode has been tested on several simulated signals and measured signals generated by Electrical Power Standards Fluke 6100A.

  10. Numerical solution of the time dependent neutron transport equation by the method of the characteristics

    SciTech Connect

    Talamo, Alberto

    2013-05-01

    This study presents three numerical algorithms to solve the time dependent neutron transport equation by the method of the characteristics. The algorithms have been developed taking into account delayed neutrons and they have been implemented into the novel MCART code, which solves the neutron transport equation for two-dimensional geometry and an arbitrary number of energy groups. The MCART code uses regular mesh for the representation of the spatial domain, it models up-scattering, and takes advantage of OPENMP and OPENGL algorithms for parallel computing and plotting, respectively. The code has been benchmarked with the multiplication factor results of a Boiling Water Reactor, with the analytical results for a prompt jump transient in an infinite medium, and with PARTISN and TDTORT results for cross section and source transients. The numerical simulations have shown that only two numerical algorithms are stable for small time steps.

  11. Alteration patterns of trabecular bone microarchitectural characteristics induced by osteoarthritis over time

    PubMed Central

    Lee, Joo Hyung; Chun, Keyoung Jin; Kim, Han Sung; Kim, Sang Ho; Han, Paul; Jun, Yongtae; Lim, Dohyung

    2012-01-01

    Information regarding the alteration of trabecular bone microarchitecture, which is one of the important criteria to estimate bone condition, induced by osteoarthritis (OA) is sparse. The current study therefore aimed to identify and quantify patterns of alterations in trabecular bone microarchitectural characteristics at tibial epiphysis induced by OA using in vivo microcomputed tomography. Fourteen 8-week-old female Sprague Dawley rats were randomly divided into control (n = 7) and OA (n = 7) groups. Rats in the OA group were administered monoiodoacetate into the knee-joint cavity. The tibial joints were scanned by in vivo microcomputed tomography at 0, 4, and 8 weeks after administration. Two-way analysis of variance with Tukeys honestly significant difference post hoc test was carried out for statistical analyses. The results showed that patterns of alterations in the trabecular bone microarchitectural characteristics in the OA group were not different from those in the control group from 0 to 4 weeks (P > 0.05), but differed from 4 to 8 weeks (P < 0.05). In particular, both trabecular bone thickness and trabecular bone separation distributions over time (48 weeks) differed significantly (P < 0.05). These findings suggest that the patterns of bone microarchitecture changes brought about by OA should be periodically considered in the diagnosis and management of arthritic symptoms over time. Improved understanding of the alteration pattern on trabecular bone microarchitecture may assist in developing more targeted treatment interventions for OA. PMID:22956865

  12. Norm stability in Jirisan National Park: effects of time, existing conditions, and background characteristics.

    PubMed

    Kim, Sang-Oh; Shelby, Bo

    2008-04-01

    Norm stability is an important issue to consider in using the normative approach as a component of resource management decision making. This study examines three major questions related to norm stability: (1) Do norms change over time? (2) Do existing conditions affect norms? (3) Do background characteristics and visitation patterns affect norms? Data used in this study were collected at a campground in the Jirisan National Park (JNP) of Korea in 1993, 1994, and 2003. A total of 396 subjects were used for the study (120 for 1993, 106 for 1994, and 170 for 2003). Changes in the standards for "quiet time" and "seeing others littering" were statistically significant, but there was no change in the standard for "number of other tents." There was little change in norm agreement or norm prevalence. Existing conditions were strongly correlated with standards for number of other tents but results were mixed for the other two indicators. Users' demographic characteristics and visitation patterns were not generally related to norms. Findings of the study are discussed. PMID:18214588

  13. Time Course of Improvements in Power Characteristics in Elite Development Netball Players Entering a Full-Time Training Program.

    PubMed

    McKeown, Ian; Chapman, Dale W; Taylor, Kristie Lee; Ball, Nick B

    2016-05-01

    McKeown, I, Chapman, DW, Taylor, KL, and Ball, NB. Time course of improvements in power characteristics in elite development netball players entering a full-time training program. J Strength Cond Res 30(5): 1308-1315, 2016-We describe the time course of adaptation to structured resistance training on entering a full-time high-performance sport program. Twelve international caliber female netballers (aged 19.9 ± 0.4 years) were monitored for 18 weeks with countermovement (CMJ: performed with body weight and 15 kg) and drop jumps (0.35-m box at body weight) at the start of each training week. Performance did not improve linearly or concurrently with loaded CMJ power improving 11% by Week 5 (effect size [ES] 0.93 ± 0.72) in contrast, substantial positive changes were observed for unloaded CMJ power (12%; ES 0.78 ± 0.39), and CMJ velocity (unloaded: 7.1%; ES 0.66 ± 0.34; loaded: 7.5%; ES 0.90 ± 0.41) by week 7. Over the investigation duration, large improvements were observed in unloaded CMJ power (24%; ES 1.45 ± 1.11) and velocity (12%; ES 1.13 ± 0.76). Loaded CMJ power also showed a large improvement (19%; ES 1.49 ± 0.97) but only moderate changes were observed for loaded CMJ velocity (8.4%; ES 1.01 ± 0.67). Jump height changes in either unloaded or loaded CMJ were unclear over the 18-week period. Drop jump performance improved throughout the investigation period with moderate positive changes in reactive strength index observed (35%; ES 0.97 ± 0.69). The adaptation response to a structured resistance training program does not occur linearly in young female athletes. Caution should be taken if assessing jump height only, as this will provide a biased observation to a training response. Frequently assessing CMJ performance can aid program design coaching decisions to ensure improvements are seen past the initial neuromuscular learning phase in performance training. PMID:26439781

  14. Lean burn limit and time to light characteristics of laser ignition in gas turbines

    NASA Astrophysics Data System (ADS)

    Griffiths, J.; Riley, M.; Kirk, A.; Borman, A.; Lawrence, J.; Dowding, C.

    2014-04-01

    This work details a study of laser ignition in a low pressure combustion test rig, representative of an industrial gas turbine (SGT-400, Siemens Industrial Turbomachinery Ltd.) and for the first time investigates the effect of air mass flow rate on combustion characteristics at air/fuel ratios at the lean burn limit. Both the lean burn limit and time taken to light are essential in determining the suitability of a specified air/fuel ratio, especially in multi-chamber ignition applications. Through extension of the lean burn limit and reduction of the time taken to light, the operating window for ignition with regards to the air/fuel ratio can be increased, leading to greater reliability and repeatability of ignition. Ignition of a natural gas and air mixture at atmospheric pressure was conducted using both a standard high energy igniter and a laser ignition system utilizing a Q-switched Nd:YAG laser source operating at 1064 nm wavelength. A detailed comparison of the lean burn limit and time taken to light for standard ignition and laser ignition is presented.

  15. Evaluation of space-time distribution of rainfall and its characteristics: A remote sensing perspective

    NASA Astrophysics Data System (ADS)

    Gebremichael, Mekonnen

    This study aims at providing a better understanding of the quantitative accuracy of the space-time distribution of rainfall and its characteristics derived from remote sensing. This will be beneficial to clearly understand the capability and limitations of remotely sensed data, to properly utilize the data, and to formulate more reliable remote sensing rainfall algorithms. The specific objectives of this study are: (1) to understand the implication of the uncertainties in the small-scale spatial statistics derived from ground-based radar; (2) to examine the uncertainties associated with space-derived rainfall estimates at a range of space-time scales; (3) to understand the implication of the uncertainties in the scaling properties of rainfall derived from the space-based radar; and (4) to investigate the scaling properties of rainfall across the entire tropics. First, this study investigates the uncertainty in the small-scale (less than 20 km) spatial statistics of rainfall derived from ground-based radar products. Second, the mean-squared uncertainty in satellite-derived rainfall estimates, which arises due to temporal gaps in satellite observations, is investigated. Third, the probability distribution functions of these temporal sampling errors are sought by examining a number of distribution models. Fourth, using the radar-derived rainfall dataset over the Mississippi River Basin as the ground-truth, the total error in the Global Precipitation Climatology Project (GPCP) one-degree daily (1DD) rainfall estimates is quantified. Fifth, the ability of the TRMM precipitation radar (PR) to characterize the scaling characteristics of rainfall is assessed by comparing the derived results with those obtained from ground-based radar data. Results show that, using the TRMM ground validation sites as the ground-truth, the TRMM PR has the ability to characterize the scaling characteristics of rainfall, though the resulting parameters will differ to some degree. Finally, this study provides a global perspective of the scaling properties of rainfall based on the TRMM PR data in terms of its characteristics, external forcing, predictability, spatial/temporal modes of variability, and applicability.

  16. Variations of characteristic time scales in rotating stratified turbulence using a large parametric numerical study.

    PubMed

    Rosenberg, D; Marino, R; Herbert, C; Pouquet, A

    2016-01-01

    We study rotating stratified turbulence (RST) making use of numerical data stemming from a large parametric study varying the Reynolds, Froude and Rossby numbers, Re, Fr and Ro in a broad range of values. The computations are performed using periodic boundary conditions on grids of 1024(3) points, with no modeling of the small scales, no forcing and with large-scale random initial conditions for the velocity field only, and there are altogether 65 runs analyzed in this paper. The buoyancy Reynolds number defined as R B = ReFr (2) varies from negligible values to [Formula: see text] 10(5), approaching atmospheric or oceanic regimes. This preliminary analysis deals with the variation of characteristic time scales of RST with dimensionless parameters, focusing on the role played by the partition of energy between the kinetic and potential modes, as a key ingredient for modeling the dynamics of such flows. We find that neither rotation nor the ratio of the Brunt-Väisälä frequency to the inertial frequency seem to play a major role in the absence of forcing in the global dynamics of the small-scale kinetic and potential modes. Specifically, in these computations, mostly in regimes of wave turbulence, characteristic times based on the ratio of energy to dissipation of the velocity and temperature fluctuations, TV and TP, vary substantially with parameters. Their ratio [Formula: see text] follows roughly a bell-shaped curve in terms of Richardson number Ri. It reaches a plateau --on which time scales become comparable, [Formula: see text] -- when the turbulence has significantly strengthened, leading to numerous destabilization events together with a tendency towards an isotropization of the flow. PMID:26830757

  17. Unified viscoelasticity: Applying discrete element models to soft tissues with two characteristic times.

    PubMed

    Anssari-Benam, Afshin; Bucchi, Andrea; Bader, Dan L

    2015-09-18

    Discrete element models have often been the primary tool in investigating and characterising the viscoelastic behaviour of soft tissues. However, studies have employed varied configurations of these models, based on the choice of the number of elements and the utilised formation, for different subject tissues. This approach has yielded a diverse array of viscoelastic models in the literature, each seemingly resulting in different descriptions of viscoelastic constitutive behaviour and/or stress-relaxation and creep functions. Moreover, most studies do not apply a single discrete element model to characterise both stress-relaxation and creep behaviours of tissues. The underlying assumption for this disparity is the implicit perception that the viscoelasticity of soft tissues cannot be described by a universal behaviour or law, resulting in the lack of a unified approach in the literature based on discrete element representations. This paper derives the constitutive equation for different viscoelastic models applicable to soft tissues with two characteristic times. It demonstrates that all possible configurations exhibit a unified and universal behaviour, captured by a single constitutive relationship between stress, strain and time as: σ+Aσ̇+Bσ¨=Pε̇+Qε¨. The ensuing stress-relaxation G(t) and creep J(t) functions are also unified and universal, derived as [Formula: see text] and J(t)=c2+(ε0-c2)e(-PQt)+σ0Pt, respectively. Application of these relationships to experimental data is illustrated for various tissues including the aortic valve, ligament and cerebral artery. The unified model presented in this paper may be applied to all tissues with two characteristic times, obviating the need for employing varied configurations of discrete element models in preliminary investigation of the viscoelastic behaviour of soft tissues. PMID:26232814

  18. Estimation of Dispersion and Characteristic Mixing Times in Plum Island Sound Estuary

    NASA Astrophysics Data System (ADS)

    Vallino, J. J.; Hopkinson, C. S., Jr.

    1998-03-01

    Salinity distributions, dye release studies, and parameter estimation techniques are used to determine the longitudinal (or tidal) dispersion coefficient in the Plum Island Sound estuary in north-eastern Massachusetts, U.S.A. A one-dimensional, intertidal, advection-dispersion model is used to test the validity of the steady-state assumption employed to estimate tidal dispersion from salinity. It is found that salinity distributions in the upper Parker River can take months to relax to steady state under low freshwater discharge conditions, so that dispersion cannot be reliably estimated using the steady-state assumption. To overcome this problem, dye release studies and parameter estimation techniques are used to determine the functionality of the dispersion coefficient that produces the best fit between the observed salinity profiles, dye plumes and model output under transient conditions for the period between 28 April 1992 and 12 April 1995. The estimated dispersion coefficient is found to be a hyperbolic function of distance from the head of the estuary and varies from an average of 3·6 m 2 s -1in the upper Parker River (0-5·2 km) to an average of 670 m 2 s -1in Plum Island Sound (14·3-24 km). The advection-dispersion model is also used to investigate three characteristic mixing-time scales involving average age, average residence time and average transit time (also called turnover or flushing time) for freshwater and saltwater sources in defined subsections of the estuary. It is found that these time scales can vary from a few hours to 3 months depending on location and freshwater discharge. Transport in the upper Parker River can be either advection or dispersion dominated depending on discharge, while Plum Island Sound is always dominated by dispersive terms. Tidal channel morphometry leads to a very dynamic system in the upper Parker River that significantly impacts ecological processes in the region. We discuss the relevance and appropriate application of the three characteristic mixing-time scales to ecological processes.

  19. Stratigraphy and Characteristic Time Scales of Northern Polar and Circumpolar Deposits on Mars

    NASA Astrophysics Data System (ADS)

    Kreslavsky, M. A.; Head, J. W.

    2002-05-01

    The north polar region is dominated by the polar cap cut by troughs and Chasma Boreale, surrounded by the north polar erg and overlying the Vastitas Borealis Formation. A thin layer of mantle with characteristic "basketball" texture typical for high latitudes covers the surface of Vastitas Borealis Formation. Study of the high-resolution MGS MOC images showed that the dunes migrate over this mantle. The stratigraphic relationships of this mantle and icy deposits, as well as Chasma Boreale-related deposits are more complex. Chasma Boreale has been interpreted to be initiated as an outflow event (Fishbaugh and Head, JGR, JE001351, 2002). We estimate that the time scale of the meltwater accumulation at the base of the polar cap and the time scale of establishing the thermal equilibrium in the cap are on the order of 0.5 Myr or greater. We compare this time scale with the characteristic astronomically predicted time scales: the time scale of obliquity oscillations (0.05 Myr), the period of obliquity oscillations about 25 deg (3.5 Myr), and the time scale of chaotic obliquity variations (5 Myr). During the period 3.5 - 5 Myr ago the obliquity oscillated around 35 deg, which led to noticeably higher polar cap temperatures and a shallower depth of the melting isotherm than during the present epoch. Predictions of obliquity in the earlier epochs beyond 5 Myr are impossible. We conclude that the period of intensive reshaping of the polar cap and formation of Chasma Boreale occurred 3.5 Myr ago or earlier. During the last 3.5 Myr the cap was rather similar to present; minor erosion and deposition of the upper layers could occur, along with modest trough migration in the short epochs of the highest obliquity. The accumulation of the main mass of the finely layered deposits occurred at least 0.5 - 1 Myr (and may be much earlier) than the Chasma Boreale flood. The accumulation could occur in response to some obliquity-driven climate variation or due to some endogenic discharge of water. The platy unit (Byrne and Murrey, JGR, JE001615, 2002) is the stratigraphically lowest part of the polar cap, and is probably noticeably older than the finely layered unit.

  20. Space and time characteristics of transmitter release at the nerve-electroplaque junction of Torpedo.

    PubMed Central

    Girod, R; Corrèges, P; Jacquet, J; Dunant, Y

    1993-01-01

    1. A loose patch electrode was used to stimulate axon terminals and to record evoked electroplaque currents (EPCs) in a limited area of innervated membrane of the electric organ of Torpedo marmorata. Electrophysiological signals were compared to the predictions of a semi-quantitative model of synaptic transmission which was designed to simulate the release of several packets of neurotransmitter molecules, at the same or at different sites of the synapse, synchronously or with various temporal patterns. 2. The amplitude distribution of EPCs evoked by activation of nerve terminals showed quantal steps. The time to peak of EPCs was in most cases independent of amplitude, but in their decaying phase a positive correlation was seen between half-decay time and amplitude. Comparison with the model suggested that (i) a dynamic interaction occurred at the end of the EPC between the fields of postsynaptic membrane activated by individual quanta, and (ii) the sites of quantal release in the electric organ are separated from each other by 600-1000 nm. 3. Spontaneous miniature electroplaque potentials (MEPPs) were recorded externally with the same type of loose patch electrode. The majority (75%) of external MEPPs displayed a homogeneous and rapid time course. This fast MEPP population had a mean time to peak of 0.43 ms, a half-decay time of 0.45 ms and a time constant of decay of 0.35 ms. 4. Despite homogeneous characteristics of time course, fast MEPPs exhibited a wide amplitude distribution with a main population which could be fitted by a Gaussian curve around 1 mV, and another population of small amplitude. Both the time-to-peak and the half-decay time of fast MEPPs showed a positive correlation with the amplitude from the smallest to the largest events. Acetylcholinesterase was not blocked. 5. In addition to the fast MEPPs, spontaneous signals exhibiting a slow rate of rise, or a slow rate of decay, or both were observed. They occurred at any time during the experiment, independently of the overall frequency. Approximately 15% of the total number of events had a slow rise but their decay phase was nevertheless rapid and could be ascribed to the kinetics of receptors. These slow-rising MEPPs exhibited a variety of conformations: slow but smooth rise, sudden change of slope and sometimes several bumps or inflexions. Their average amplitude was significantly smaller than that of the main population of fast MEPPs. 6. Composite MEPPs with multiple peaks as well as bursts of small MEPPs were often encountered, even during periods of low frequency.(ABSTRACT TRUNCATED AT 400 WORDS) Images Fig. 1 PMID:8120801

  1. A variable-order time-dependent neutron transport method for nuclear reactor kinetics using analytically-integrated space-time characteristics

    SciTech Connect

    Hoffman, A. J.; Lee, J. C.

    2013-07-01

    A new time-dependent neutron transport method based on the method of characteristics (MOC) has been developed. Whereas most spatial kinetics methods treat time dependence through temporal discretization, this new method treats time dependence by defining the characteristics to span space and time. In this implementation regions are defined in space-time where the thickness of the region in time fulfills an analogous role to the time step in discretized methods. The time dependence of the local source is approximated using a truncated Taylor series expansion with high order derivatives approximated using backward differences, permitting the solution of the resulting space-time characteristic equation. To avoid a drastic increase in computational expense and memory requirements due to solving many discrete characteristics in the space-time planes, the temporal variation of the boundary source is similarly approximated. This allows the characteristics in the space-time plane to be represented analytically rather than discretely, resulting in an algorithm comparable in implementation and expense to one that arises from conventional time integration techniques. Furthermore, by defining the boundary flux time derivative in terms of the preceding local source time derivative and boundary flux time derivative, the need to store angularly-dependent data is avoided without approximating the angular dependence of the angular flux time derivative. The accuracy of this method is assessed through implementation in the neutron transport code DeCART. The method is employed with variable-order local source representation to model a TWIGL transient. The results demonstrate that this method is accurate and more efficient than the discretized method. (authors)

  2. Thermal characteristics of time-periodic electroosmotic flow in a circular microchannel

    NASA Astrophysics Data System (ADS)

    Moghadam, Ali Jabari

    2015-10-01

    A theoretical analysis is performed to explore the thermal characteristics of electroosmotic flow in a circular microchannel under an alternating electric field. An analytical approach is presented to solve energy equation, and then, the exact solution of temperature profiles is obtained by using the Green's function method. This study reveals that the temperature field repeats itself for each half-period. Frequency has a strong influence on the thermal behavior of the flow field. For small values of the dimensionless frequency (small channel size, large kinematic viscosity, or small frequency), the advection mechanism is dominant in the whole domain and the resultant heating (Joule heating and wall heat flux) can be transferred by the complete flow field in the axial direction; while, the middle portion of the flow field at high dimensionless frequencies does not have sufficient time to transfer heat by advection, and the bulk fluid temperature, especially in heating, may consequently become greater than the wall temperature. In a particular instance of cooling mode, a constant surface temperature case is temporarily occurred in which the axial temperature gradient will be zero. For relatively high frequencies, the unsteady bulk fluid temperature in some radial positions at some moments may be equal to the wall temperature; hence instantaneous cylindrical surfaces with zero radial heat flux may occur over a period of time. Depending on the value and sign of the thermal scale ratio, the quasi-steady-state Nusselt number (time-averaged at one period) approaches a specific value as the electrokinetic radius becomes infinity.

  3. [Sensing characteristics of a real-time monitor using a photoionization detector on organic solvent vapors].

    PubMed

    Hori, Hajime; Ishematsu, Sumiyo; Fueta, Yukiko; Hinoue, Mitsuo; Ishidao, Toru

    2012-12-01

    Measurements of organic solvents in the work environment are carried out by either direct sampling using plastic bags/gas chromatography, solid sorbent adsorption using charcoal tubes/gas chromatography, or by a direct reading method using detector tubes. However, these methods cannot always measure the work environment accurately because the concentration of hazardous materials changes from time to time, and from space to space. In this study, the sensor characteristics of a real time monitor using a photoionization detector that can monitor vapor concentration continuously were investigated for 52 organic solvent vapors that are required to be measured in the work environment by the Ordinance of Organic Solvent Poisoning Prevention in Japan. The sensitivity of the monitor was high for the solvents with low ionization potential. However, the sensitivity for the solvents with high ionization potential was low, and the sensor could not detected 7 solvents. Calibration of the sensor using a standard gas was desirable before being used for measurement because the sensitivity of the sensor was variable. PMID:23270260

  4. Measurements of admittances and characteristic combustion times of reactive gaseous propellant coaxial injectors

    NASA Technical Reports Server (NTRS)

    Janardan, B. A.; Daniel, B. R.; Zinn, B. T.

    1979-01-01

    The results of an experimental investigation that was concerned with the quantitative determination of the capabilities of combustion processes associated with coaxial injectors to amplify and sustain combustor oscillations was described. The driving provided by the combustion process was determined by employing the modified standing-wave method utilizing coaxial injectors and air-acetylene mixtures. Analyses of the measured data indicate that the investigated injectors are capable of initiating and amplifying combustion instabilities under favorable conditions of injector-combustion coupling and over certain frequency ranges. These frequency ranges and the frequency at which an injector's driving capacity is maximum are observed to depend upon the equivalence ratio, the pressure drop across the injector orifices and the number of injector elements. The characteristic combustion times of coaxial injectors were determined from steady state temperature measurements.

  5. Force-time curve characteristics of dynamic and isometric muscle actions of elite women olympic weightlifters.

    PubMed

    Haff, G Gregory; Carlock, Jon M; Hartman, Michael J; Kilgore, J Lon; Kawamori, Naoki; Jackson, Janna R; Morris, Robert T; Sands, William A; Stone, Michael H

    2005-11-01

    Six elite women weightlifters were tested to evaluate force-time curve characteristics and intercorrelations of isometric and dynamic muscle actions. Subjects performed isometric and dynamic mid-thigh clean pulls at 30% of maximal isometric peak force and 100 kg from a standardized position on a 61.0 x 121.9 cm AMTI forceplate. Isometric peak force showed strong correlations to the athletes' competitive snatch, clean and jerk, and combined total (r = 0.93, 0.64, and 0.80 respectively). Isometric rate of force development showed moderate to strong relationships to the athletes' competitive snatch, clean and jerk, and combined total (r = 0.79, 0.69, and 0.80 respectively). The results of this study suggest that the ability to perform maximal snatch and clean and jerks shows some structural and functional foundation with the ability to generate high forces rapidly in elite women weightlifters. PMID:16287343

  6. Nonlinear parametrically excited vibration and active control of gear pair system with time-varying characteristic

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Wang, Jin-Jin; Liu, Jin-Jie; Li, Ya-Qian

    2015-10-01

    In the present work, we investigate the nonlinear parametrically excited vibration and active control of a gear pair system involving backlash, time-varying meshing stiffness and static transmission error. Firstly, a gear pair model is established in a strongly nonlinear form, and its nonlinear vibration characteristics are systematically investigated through different approaches. Several complicated phenomena such as period doubling bifurcation, anti period doubling bifurcation and chaos can be observed under the internal parametric excitation. Then, an active compensation controller is designed to suppress the vibration, including the chaos. Finally, the effectiveness of the proposed controller is verified numerically. Project supported by the National Natural Science Foundation of China (Grant No. 61104040), the Natural Science Foundation of Hebei Province, China (Grant No. E2012203090), and the University Innovation Team of Hebei Province Leading Talent Cultivation Project, China (Grant No. LJRC013).

  7. [Stormflow hydrochemical characteristics at different time scales in a typical karst catchment of northwest Guangxi, China].

    PubMed

    Liu, Chun; Yang, Jing; Nie, Yun-peng; Chen, Hong-song; Fu, Zhi-yong

    2015-09-01

    Through in situ observation and indoor tests, the hydrochemical characteristics of a typical karst watershed at three different time scales (diurnal, single storm, and seasonal scales) from June 2013 to March 2014 were investigated, and their influencing factors were analyzed. The results showed that the diurnal variations of the hydrochemistry exhibited a regular changing pattern resulting from the shifting of the main vegetation physiological activity from photosynthesis in the day to respiration in the night. At single storm scale, however, the hydrochemical processes were mainly determined by the number of consecutive rainless days and rainfall intensity, while the diurnal scale effect was weakened. As to the seasonal scale, the overall hydrochemical processes showed quick responses to rainfall events although they responded more quickly in the rainy season than in the dry season. The temperature and the yearly rainfall distribution regime were the two main influencing factors at this scale. PMID:26785541

  8. Discovering the Impact of Preceding Units' Characteristics on the Wait Time of Cardiac Surgery Unit from Statistic Data

    PubMed Central

    Liu, Jiming; Tao, Li; Xiao, Bo

    2011-01-01

    Introduction Prior research shows that clinical demand and supplier capacity significantly affect the throughput and the wait time within an isolated unit. However, it is doubtful whether characteristics (i.e., demand, capacity, throughput, and wait time) of one unit would affect the wait time of subsequent units on the patient flow process. Focusing on cardiac care, this paper aims to examine the impact of characteristics of the catheterization unit (CU) on the wait time of cardiac surgery unit (SU). Methods This study integrates published data from several sources on characteristics of the CU and SU units in 11 hospitals in Ontario, Canada between 2005 and 2008. It proposes a two-layer wait time model (with each layer representing one unit) to examine the impact of CU's characteristics on the wait time of SU and test the hypotheses using the Partial Least Squares-based Structural Equation Modeling analysis tool. Results Results show that: (i) wait time of CU has a direct positive impact on wait time of SU (); (ii) capacity of CU has a direct positive impact on demand of SU (); (iii) within each unit, there exist significant relationships among different characteristics (except for the effect of throughput on wait time in SU). Conclusion Characteristics of CU have direct and indirect impacts on wait time of SU. Specifically, demand and wait time of preceding unit are good predictors for wait time of subsequent units. This suggests that considering such cross-unit effects is necessary when alleviating wait time in a health care system. Further, different patient risk profiles may affect wait time in different ways (e.g., positive or negative effects) within SU. This implies that the wait time management should carefully consider the relationship between priority triage and risk stratification, especially for cardiac surgery. PMID:21818282

  9. Investigation of hydrological time series using copulas for detecting catchment characteristics and anthropogenic impacts

    NASA Astrophysics Data System (ADS)

    Sugimoto, T.; Bárdossy, A.; Pegram, G. S. S.; Cullmann, J.

    2015-09-01

    Global climate change can have impacts on characteristics of rainfall-runoff events and subsequently on the hydrological regime. Meanwhile, the catchment itself changes due to anthropogenic influences. In this context, it can be meaningful to detect the temporal changes of catchments independent from climate change by investigating existing long term discharge records. For this purpose, a new stochastic system based on copulas for time series analysis is introduced. While widely used time series models are based on linear combinations of correlations assuming a Gaussian behavior of variables, a statistical tool like copula has the advantage to scrutinize the dependence structure of the data in the uniform domain independent of the marginal. Two measures in the copula domain are introduced herein: 1. Copula asymmetry is defined for copulas and calculated for discharges; this measure describes the non symmetric property of the dependence structure and differs from one catchment to another due to the intrinsic nature of both runoff and catchment. 2. Copula distance is defined as Cramér-von Mises type distance calculated between two copula densities of different time scales. This measure describes the variability and interdependency of dependence structures similar to variance and covariance, which can assist in identifying the catchment changes. These measures are calculated for 100 years of daily discharges for the Rhine rivers. Comparing the results of copula asymmetry and copula distance between an API and simulated discharge time series by a hydrological model we can show the interesting signals of systematic modifications along the Rhine rivers in the last 30 years.

  10. Time variations in the mechanical characteristics of local crustal segments according to seismic observations

    NASA Astrophysics Data System (ADS)

    Kocharyan, G. G.; Gamburtseva, N. G.; Sanina, I. A.; Danilova, T. V.; Nesterkina, M. A.; Gorbunova, E. M.; Ivanchenko, G. N.

    2011-04-01

    The results of the seismic observations made with two different experimental setups are presented. In the first case, the signals produced by underground nuclear explosions at the Semipalatinsk Test Site were measured on a linear profile, which allowed one to definitely outline the areas where the mechanical properties of rocks experienced considerable time variations. In the second case, the waves excited by the open-pit mine blasts recorded at a small-aperture seismic array at the Mikhnevo Geophysical Station (Institute of Geosphere Dynamics, Russian Academy of Sciences) on the East European Platform favored the estimation of variations in the integral characteristics of the seismic path. Measurements in aseismic regions characterized by diverse geological structure and different tectonic conditions revealed similar effects of the strong dependency of seismic parameters on the time of explosions. Here, the variations experienced by the maximum amplitudes of oscillations and irrelevant to seasonal changes or local conditions reached a factor of two. The generic periods of these variations including the distinct annual rhythm are probably the fragments of a lower-frequency process. The obtained results suggest that these variations are due to changes in the stressstrain state of active fault zones, which, in turn, can be associated with the macroscale motion of large blocks triggered by tidal strains, tectonic forces and, possibly, variations in the rate of the Earth's rotation.

  11. Permeability models of porous media: Characteristic length scales, scaling constants and time-dependent electrokinetic coupling

    NASA Astrophysics Data System (ADS)

    Glover, Paul; Walker, Emile

    2010-05-01

    Four important models that describe the fluid permeability of geological porous media and that are derived from different physical approaches have been rewritten in a generic form that implies a characteristic scale length and scaling constant for each model. The four models have been compared theoretically and using experimental data from 22 bead packs and 188 rock cores from a sand-shale sequence in the UK sector of the North Sea. The Kozeny-Carman model did not perform well because it takes no account of the connectedness of the pore network, and should no longer be used. The other three models (Schwartz, Sen and Johnson (SSJ), Katz and Thompson (KT) and the so-called RGPZ) all performed well when used with their respective length scales and scaling constants. Surprisingly, we have found that the SSJ and KT models are extremely similar, such that their characteristic scale lengths and scaling constants are almost identical even though they are derived using extremely different approaches; the SSJ model by weighting the Kozeny-Carman model using the local electric field, the KT model using entry radii from fluid imbibition measurements. The experimentally determined scaling constants for each model were found to be cSSJ ≈ cKT ≈ 8/3 ≈ cRGPZ/3. Use of these models with AC electrokinetic theory has also allowed us to show that these scaling constants are also related to the a value in the RGPZ model and the m* value in time-dependent electrokinetic theory, and then derive a relationship between the electrokinetic transition frequency and the RGPZ scale length, which we have validated using experimental data. The practical implication of this work for permeability prediction is that the Katz and Thompson model should be used when fluid imbibition data is available, while the RGPZ model should be used when electrical data is available.

  12. The time course and characteristics of procedural learning in schizophrenia patients and healthy individuals

    PubMed Central

    Adini, Yael; Bonneh, Yoram S.; Komm, Seva; Deutsch, Lisa; Israeli, David

    2015-01-01

    Patients with schizophrenia have deficits in some types of procedural learning. Several mechanisms contribute to this learning in healthy individuals, including statistical and sequence-learning. To find preserved and impaired learning mechanisms in schizophrenia, we studied the time course and characteristics of implicitly introduced sequence-learning (SRT task) in 15 schizophrenia patients (seven mild and eight severe) and nine healthy controls, in short sessions over multiple days (5–22). The data show speed gains of similar magnitude for all groups, but the groups differed in overall speed and in the characteristics of the learning. By analyzing the data according to its spatial-position and temporal-order components, we provide evidence for two types of learning that could differentiate the groups: while the learning of the slower, severe group was dominated by statistical learning, the control group moved from a fast learning phase of statistical-related performance to subsequence learning (chunking). Our findings oppose the naïve assumption that a similar gain of speed reflects a similar learning process; they indicate that the slower performance reflects the activation of a different motor plan than does the faster performance; and demonstrate that statistical learning and subsequence learning are two successive stages in implicit sequence learning, with chunks inferred from prior statistical computations. Our results indicate that statistical learning is intact in patients with schizophrenia, but is slower to develop in the severe patients. We suggest that this slow learning rate and the associated slow performance contribute to their deficit in developing sequence-specific learning by setting a temporal constraint on developing higher order associations. PMID:26379536

  13. Characteristics of Four SPE Classes According to Onset Timing and Proton Acceleration Patterns

    NASA Astrophysics Data System (ADS)

    Kim, Roksoon

    2015-04-01

    In our previous work (Kim et al., 2015), we suggested a new classification scheme, which categorizes the SPEs into four groups based on association with flare or CME inferred from onset timings as well as proton acceleration patterns using multienergy observations. In this study, we have tried to find whether there are any typical characteristics of associated events and acceleration sites in each group using 42 SPEs from 1997 to 2012. We find: (i) if the proton acceleration starts from a lower energy, a SPE has a higher chance to be a strong event (> 5000 pfu) even if the associated flare and CME are not so strong. The only difference between the SPEs associated with flare and CME is the location of the acceleration site. For the former, the sites are very low ( ~1 Rs) and close to the western limb, while the latter has a relatively higher (mean=6.05 Rs) and wider acceleration sites. (ii) When the proton acceleration starts from the higher energy, a SPE tends to be a relatively weak event (< 1000 pfu), in spite of its associated CME is relatively stronger than previous group. (iii) The SPEs categorized by the simultaneous proton acceleration in whole energy range within 10 minutes, tend to show the weakest proton flux (mean=327 pfu) in spite of strong related eruptions. Their acceleration heights are very close to the locations of type II radio bursts. Based on those results, we suggest that the different characteristics of the four groups are mainly due to the different mechanisms governing the acceleration pattern and interval, and different condition such as the acceleration location.

  14. Comparison of sporadic sodium layer characteristics observed at different time resolutions

    NASA Astrophysics Data System (ADS)

    Liu, Y. J.; Clemesha, B. R.; Wang, J. H.; Cheng, X. W.

    2013-11-01

    Sporadic sodium (Nas) layers, occurring in roughly the same height range as ionospheric sporadic-E layers, were first detected by lidar some 30 yr ago. Nas layers have a typical thickness of a few hundred meters to a few km, with peak atom concentrations several times that of the background layer. Despite a great deal of excellent work over the past decades, the source of Nas layers is still not altogether clear, partly as a result of our incomplete knowledge of Nas layer characteristics. In this paper we concentrate on some typical case studies chosen from the ~127 h of sporadic sodium layer observations made at a time resolution of 1.5 s at Yanqing (115.97° E, 40.47° N), Beijing, China. This is a much better time resolution than what has been employed in most earlier measurements. The results show that the Nas layer peak heights are dispersed at slightly different although adjacent heights. When averaged over several minutes, as has been the case with most earlier measurements, the height scatter results in an apparent layer thickness of a few km. We conclude, therefore, that these dispersed peaks at different but adjacent heights constitute the 5 min Nas layer. Similar to the observations of sporadic-E-ion (Es) layers and meteor rate, we observe quasi-periodic fluctuations on a timescale on the order of several minutes in the peak height and the peak density of sporadic layers, which is a universal feature but concealed by the lower temporal resolution previously adopted. Spatially localized multiple scatterers and multiple thin layers with similar apparent movement in Nas layers are also found. We discuss the possible formation mechanism by the direct deposition of large swarms of micrometeoroids and demonstrate a typical example of meteor trails evolving into a Nas layer, which suggests that this mechanism might indeed occur.

  15. Neighborhood contextual characteristics and leisure-time physical activity: Pr-Sade Study

    PubMed Central

    Boclin, Karine de Lima Srio; Faerstein, Eduardo; de Leon, Antnio Carlos Monteiro Ponce

    2014-01-01

    OBJECTIVE To estimate the association between neighborhood contextual variables and leisure-time physical activity. METHODS Data were analyzed for 2,674 adults from Rio de Janeiro, RJ, Southeastern Brazil, participating in the longitudinal study in 1999. Leisure-time physical activity in the two preceding weeks was assessed dichotomously. Sex, age, income, education and marital status were analyzed as individual variables. Neighborhood contextual characteristics were the social development index, the Theil index and the proportion of the area occupied by parks, squares and gardens, categorized in quintiles. The unadjusted and adjusted odds ratios and 95% confidence intervals were estimated using multilevel logistic regression. RESULTS The prevalence of leisure-time physical activity was higher in residents in neighborhoods with higher indices of social development (between 32.3% and 53.1%) and a greater proportion of parks, squares and gardens (between 35.8% and 53.1%). Regarding the social development index, the adjusted odds ratios for physical activity were 1.22 (95%CI 0.93;1.61), 1.44 (95%CI 1.09;1.89), 1.75 (95%CI 1.31;2.34) and 2.25 (95%CI 1.70;3.00) for residents in neighborhoods in the second, third, fourth and fifth quintiles, respectively, compared with residents in neighborhoods in the first quintile. The odds ratios for the proportion of parks, squares and gardens were 0.90 (95%CI 0.69;1.19), 1.41 (95%CI 1.04;1.90), 1.63 (95%CI 1.24;2.14) and 1.05 (95%CI 0.80;1.38) for residents in neighborhoods in the second, third, fourth and fifth quintiles. After adjusting for the other variables, only the social development index continued to be associated with leisure-time physical activity, with odds ratios of 1.41 (95%CI 1.02;1.95); 1.54 (95%CI 1.12;2.12); 1.65 (95%CI 1.14;2.39) and 2.13 (95%CI 1.40;3.25) for residents in neighborhoods in the second, third, fourth and fifth quintiles. CONCLUSIONS Leisure-time physical activity was more common in residents in neighborhoods with higher social development indices. No association was observed between access to leisure areas and income inequality. PMID:24897046

  16. Characteristics of first-time fathers of advanced age: a Norwegian population-based study

    PubMed Central

    2013-01-01

    Background The modern phenomenon of delayed parenthood applies not only to women but also to men, but less is known about what characterises men who are expecting their first child at an advanced age. This study investigates the sociodemographic characteristics, health behaviour, health problems, social relationships and timing of pregnancy in older first-time fathers. Methods A cross-sectional study was conducted of 14 832 men who were expecting their first child, based on data from the Norwegian Mother and Child Cohort Study (MoBa) carried out by the Norwegian Institute of Public Health. Data were collected in 2005–2008 by means of a questionnaire in gestational week 17–18 of their partner’s pregnancy, and from the Norwegian Medical Birth Register. The distribution of background variables was investigated across the age span of 25 years and above. Men of advanced age (35–39 years) and very advanced age (40 years or more) were compared with men aged 25–34 years by means of bivariate and multivariate logistic regression analyses. Results The following factors were found to be associated with having the first child at an advanced or very advanced age: being unmarried or non-cohabitant, negative health behaviour (overweight, obesity, smoking, frequent alcohol intake), physical and mental health problems (lower back pain, cardiovascular diseases, high blood pressure, sleeping problems, previous depressive symptoms), few social contacts and dissatisfaction with partner relationship. There were mixed associations for socioeconomic status: several proxy measures of high socioeconomic status (e.g. income >65 000 €, self-employment) were associated with having the first child at an advanced or very advanced age, as were several other proxy measures of low socioeconomic status (e.g. unemployment, low level of education, immigrant background).The odds of the child being conceived after in vitro fertilisation were threefold in men aged 34–39 and fourfold from 40 years and above. Conclusions Men who expect their first baby at an advanced or very advanced age constitute a socioeconomically heterogeneous group with more health problems and more risky health behaviour than younger men. Since older men often have their first child with a woman of advanced age, in whom similar characteristics have been reported, their combined risk of adverse perinatal outcomes needs further attention by clinicians and researchers. PMID:23363654

  17. Evaluation of the amperex 56 TVP photomultiplier. [characteristics: photoelectron time spread, anode pulse amplitude and photocathode sensing area

    NASA Technical Reports Server (NTRS)

    Lo, C. C.; Leskovar, B.

    1976-01-01

    Characteristics were measured for the Amperex 56 TVP 42 mm-diameter photomultiplier. Some typical photomultiplier characteristics-such as gain, dark current, transit and rise times-are compared with data provided. Photomultiplier characteristics generally not available such as the single photoelectron time spread, the relative collection efficiency, the relative anode pulse amplitude as a function of the voltage between the photocathode and focusing electrode, and the position of the photocathode sensing area were measured and are discussed for two 56 TVP's. The single photoelectron time spread, the relative collection efficiency, and the transit time difference as a function of the voltage between photocathode and focusing electrode were also measured and are discussed, particularly with respect to the optimization of photomultiplier operating conditions for timing applications.

  18. Ionization characteristics of amino acids in direct analysis in real time mass spectrometry.

    PubMed

    Sekimoto, Kanako; Sakakura, Motoshi; Kawamukai, Takatomo; Hike, Hiroshi; Shiota, Teruhisa; Usui, Fumihiko; Bando, Yasuhiko; Takayama, Mitsuo

    2014-05-21

    The positive and negative ionization characteristics of 20 different ?-amino acids were investigated using Direct Analysis in Real Time (DART) mass spectrometry. Almost all of the amino acids M were ionized to generate the (de)protonated analytes [M H]()via proton transfer reactions with the typical background ions H3O(+)(H2O)n and O2?(-) and resonant electron capture by M. The application of DART to amino acids also resulted in molecular ion formation, fragmentation, oxidations involving oxygen attachment and hydrogen loss, and formation of adducts [M + R](-) with negative background ions R(-) (O2?(-), HCO2(-), NO2(-) and COO(-)(COOH)), depending on the physicochemical and/or structural properties of individual amino acids. The relationship between each amino acid and the ionization reactions observed suggested that fragmentation can be attributed to pyrolysis during analyte desorption as well as excess energy obtained via (de)protonation. Oxidation and [M + R](-) adduct formation, in contrast, most likely originate from reactions with active oxygen such as hydroxyl radicals HO?, indicating that the typical background neutral species involved in analyte ionization in DART mass spectrometry contain HO?. PMID:24707507

  19. Suicidality and sexual orientation: Characteristics of symptom severity, disclosure, and timing across the life course.

    PubMed

    Blosnich, John R; Nasuti, Laura J; Mays, Vickie M; Cochran, Susan D

    2016-01-01

    This investigation explored suicide-related characteristics and help-seeking behavior by sexual orientation. Population-based data are from the California Quality of Life Surveys, which included 1,478 sexual minority (lesbian, gay, bisexual, and homosexually experienced individuals) and 3,465 heterosexual individuals. Bisexual women had a nearly six-fold increased risk of lifetime suicide attempts than heterosexual women (RR = 5.88, 95%CI: 3.89-8.90), and homosexually experienced men had almost 7 times higher risk of lifetime suicide attempts than heterosexual men (RR = 6.93, 95%CI: 3.65-13.15). Sexual minority men and women were more likely than heterosexual men and women to have disclosed suicide attempts to a medical professional (RR = 1.48 and RR = 1.44, respectively). Among persons who ever attempted suicide, sexual minority women had a younger age of index attempt than heterosexual women (15.9 vs. 19.6 years of age, respectively). Healthcare professionals should be aware of suicidal risk heterogeneity among sexual minority individuals, including vulnerable points of risk and evidenced-based treatments. PMID:26752446

  20. As time goes by: reasons and characteristics of prolonged episodes of mechanical restraint in forensic psychiatry.

    PubMed

    Gildberg, Frederik A; Fristed, Peter; Makransky, Guido; Moeller, Elsebeth H; Nielsen, Lea D; Bradley, Stephen K

    2015-01-01

    Evidence suggests the prevalence and duration of mechanical restraint are particularly high among forensic psychiatric inpatients. However, only sparse knowledge exists regarding the reasons for, and characteristics of, prolonged use of mechanical restraint in forensic psychiatry. This study therefore aimed to investigate prolonged episodes of mechanical restraint on forensic psychiatric inpatients. Documentary data from medical records were thematically analyzed. Results show that the reasons for prolonged episodes of mechanical restraint on forensic psychiatric inpatients can be characterized by multiple factors: "confounding" (behaviors associated with psychiatric conditions, substance abuse, medical noncompliance, etc.), "risk" (behaviors posing a risk for violence), and "alliance parameters" (qualities of the staff-patient alliance and the patients' openness to alliance with staff), altogether woven into a mechanical restraint spiral that in itself becomes a reason for prolonged mechanical restraint. The study also shows lack of consistent clinical assessment during periods of restraint. Further investigation is indicated to develop an assessment tool with the capability to reduce time spent in mechanical restraint. PMID:25622065

  1. Identification of Land-Cover Characteristics Using MODIS Time Series Data: An Application in the Yangtze River Estuary

    PubMed Central

    Zhang, Mo-Qian; Guo, Hai-Qiang; Xie, Xiao; Zhang, Ting-Ting; Ouyang, Zu-Tao; Zhao, Bin

    2013-01-01

    Land-cover characteristics have been considered in many ecological studies. Methods to identify these characteristics by using remotely sensed time series data have previously been proposed. However, these methods often have a mathematical basis, and more effort is required to better illustrate the ecological meanings of land-cover characteristics. In this study, a method for identifying these characteristics was proposed from the ecological perspective of sustained vegetation growth trend. Improvement was also made in parameter extraction, inspired by a method used for determining the hyperspectral red edge position. Five land-cover types were chosen to represent various ecosystem growth patterns and MODIS time series data were adopted for analysis. The results show that the extracted parameters can reflect ecosystem growth patterns and portray ecosystem traits such as vegetation growth strategy and ecosystem growth situations. PMID:23894594

  2. Spatial gravity wave characteristics obtained from multiple OH(3-1) airglow temperature time series

    NASA Astrophysics Data System (ADS)

    Wachter, Paul; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael

    2015-12-01

    We present a new approach for the detection of gravity waves in OH-airglow observations at the measurement site Oberpfaffenhofen (11.27°E, 48.08°N), Germany. The measurements were performed at the German Remote Sensing Data Center (DFD) of the German Aerospace Center (DLR) during the period from February 4th, 2011 to July 6th, 2011. In this case study the observations were carried out by three identical Ground-based Infrared P-branch Spectrometers (GRIPS). These instruments provide OH(3-1) rotational temperature time series, which enable spatio-temporal investigations of gravity wave characteristics in the mesopause region. The instruments were aligned in such a way that their fields of view (FOV) formed an equilateral triangle in the OH-emission layer at a height of 87 km. The Harmonic Analysis is applied in order to identify joint temperature oscillations in the three individual datasets. Dependent on the specific gravity wave activity in a single night, it is possible to detect up to four different wave patterns with this method. The values obtained for the waves' periods and phases are then used to derive further parameters, such as horizontal wavelength, phase velocity and the direction of propagation. We identify systematic relationships between periods and amplitudes as well as between periods and horizontal wavelengths. A predominant propagation direction towards the East and North-North-East characterizes the waves during the observation period. There are also indications of seasonal effects in the temporal development of the horizontal wavelength and the phase velocity. During late winter and early spring the derived horizontal wavelengths and the phase velocities are smaller than in the subsequent period from early April to July 2011.

  3. Effect of various loads on the force-time characteristics of the hang high pull.

    PubMed

    Suchomel, Timothy J; Beckham, George K; Wright, Glenn A

    2015-05-01

    The purpose of this study was to investigate the effect of various loads on the force-time characteristics associated with peak power during the hang high pull (HHP). Fourteen athletic men (age: 21.6 1.3 years; height: 179.3 5.6 cm; body mass: 81.5 8.7 kg; 1 repetition maximum [1RM] hang power clean [HPC]: 104.9 15.1 kg) performed sets of the HHP at 30, 45, 65, and 80% of their 1RM HPC. Peak force, peak velocity, peak power, force at peak power, and velocity at peak power were compared between loads. Statistical differences in peak force (p = 0.001), peak velocity (p < 0.001), peak power (p = 0.015), force at peak power (p < 0.001), and velocity at peak power (p < 0.001) existed, with the greatest values for each variable occurring at 80, 30, 45, 80, and 30% 1RM HPC, respectively. Effect sizes between loads indicated that larger differences in velocity at peak power existed as compared with those displayed by force at peak power. It seems that differences in velocity may contribute to a greater extent to differences in peak power production as compared with force during the HHP. Further investigation of both force and velocity at peak power during weightlifting variations is necessary to provide insight on the contributing factors of power production. Specific load ranges should be prescribed to optimally train the variables associated with power development during the HHP. PMID:25426514

  4. Winter time chemical characteristics of aerosols over the Bay of Bengal: continental influence.

    PubMed

    Aryasree, S; Nair, Prabha R; Girach, I A; Jacob, Salu

    2015-10-01

    As part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) conducted under the Geosphere Biosphere Programme of Indian Space Research Organisation, ship-based aerosol sampling was carried out over the marine environment of Bay of Bengal (BoB) during the northern winter months of December 2008 to January 2009. About 101 aerosol samples were collected, covering the region from 3.4° to 21° N latitude and 76° to 98° E longitude-the largest area covered-including the south east (SE) BoB for the first time. These samples were subjected to gravimetric and chemical analysis and the total aerosol loading as well the mass concentration of the ionic species namely F(-), Cl(-), Br(-), NO2 (-), NO3 (-), PO4 (2-), SO4 (2-), NH4 (+), etc. and the metallic species, Na, Mg, Ca, K, Al, Fe, Mn, Zn, and Pb were estimated for each sample. Based on the spatial distribution of individual chemical species, the air flow pattern, and airmass back trajectory analysis, the source characteristics of aerosols for different regions of BoB were identified. Significant level of continental pollution was noticed over BoB during winter. While transport of pollution from Indo-Gangetic Plain (IGP) contributed to aerosols over north BoB, those over SE BoB were influenced by SE Asia. A quantitative study on the wind-induced production of sea salt aerosols and a case study on the species dependent effect of rainfall are also presented in this paper. PMID:25994269

  5. Assessing the Value of Regulation Resources Based on Their Time Response Characteristics

    SciTech Connect

    Makarov, Yuri V.; Lu, Shuai; Ma, Jian; Nguyen, Tony B.

    2008-06-01

    Fast responsive regulation resources are potentially more valuable as a power system regulation resource (more efficient) because they allow applying controls at the exact moment and in the exact amount as needed. Faster control is desirable because it facilitates more reliable compliance with the NERC Control Performance Standards at relatively lesser regulation capacity procurements. The current California ISO practices and markets do not provide a differentiation among the regulation resources based on their speed of response (with the exception of some minimum ramping capabilities). Some demand response technologies, including some generation and energy storage resources, can provide quicker control actions. California ISO practices and markets could be updated to welcome more fast regulation resources into the California ISO service area. The project work reported in this work was pursuing the following objectives: • Develop methodology to assess the relative value of generation resources used for regulation and load following California ISO functions • This assessment should be done based on physical characteristics including the ability to quickly change their output following California ISO signals • Evaluate what power is worth on different time scales • Analyze the benefits of new regulation resources to provide effective compliance with the mandatory NERC Control Performance Standards • Evaluate impacts of the newly proposed BAAL and FRR standards on the potential value of fast regulation and distributed regulation resources • Develop a scope for the follow-up projects to pave a road for the new efficient types of balancing resources in California. The work included the following studies: • Analysis of California ISO regulating units characteristics • California ISO automatic generation system (AGC) analysis • California ISO regulation procurement and market analysis • Fast regulation efficiency analysis • Projection of the California ISO load following and regulation requirements into the future • Value of fast responsive resources depending on their ramping capability • Potential impacts of the balancing authority area control error limit (BAAL), which is a part of the newly proposed NERC standard “Balancing Resources and Demand” • Potential impacts of the Western Electricity Coordinating Council (WECC) frequency responsive reserve (FRR) standard • Recommendations for the next phase of the project. The following main conclusions and suggestions for the future have been made: • The analysis of regulation ramping requirements shows that the regulation system should be able to provide ramps of at least 40-60 MW per minute for a period up to 6 minutes. • Evaluate if changes are needed in the California ISO AGC system to effectively accommodate new types of fast regulation resources and minimize the California ISO regulation procurement. • California ISO may consider creating better market opportunities for and incentives for fast responsive resources. • An additional study of low probability high ramp events can be recommended to the California ISO. • The California ISO may be willing to consider establishing a more relaxed target CPS2 compliance level. • A BAAL-related study can be recommended for the California ISO as soon as more clarity is achieved concerning the actual enforcement of the BAAL standard and its numerical values for the California ISO. The study may involve an assessment of advantages of the distributed frequency-based control for the California ISO system. The market-related issues that arise in this connection can be also investigated. • A FRR-related study can be recommended for the California ISO as soon as more clarity is achieved concerning the actual enforcement of the FRR standard and its numerical values for the California ISO.

  6. Temporal direct numerical simulation of transitional natural-convection boundary layer under conditions of considerable external turbulence effects

    NASA Astrophysics Data System (ADS)

    Abramov, Alexey G.; Smirnov, Evgueni M.; Goryachev, Valery D.

    2014-08-01

    Results of direct numerical simulations for time-developing air natural-convection boundary layer are presented. Computations have been performed assuming periodicity conditions in both the directions parallel to the vertical isothermal hot plate. The contribution is mainly focused on understanding of laminar-turbulent transition peculiarities in the case of perturbation action of external turbulence that is modeled by isotropic disturbances initially introduced into the computational domain. Special attention is paid to identification and analysis of evolving three-dimensional vortices that clearly manifest themselves through the whole stages of laminar-turbulent transition in the boundary layer. A comparison of computed profiles of mean velocity, mean temperature and fluctuation characteristics for turbulent regimes of convection with experimental data is performed as well.

  7. Study of the time-frequency characteristics of continuous gravity data sequence

    NASA Astrophysics Data System (ADS)

    Weimin, X.; Shi, C.; Lei, S.; Hongyan, L.

    2013-12-01

    The continuous gravity measurements contained much valuable signal which was maybe caused by internal and external change of the Earth, which offered abundant information to study activities of the Earth. In the past decades, researchers mostly focused on discussing the relationship between the gravity variation and geodynamical processes. Here we studied the temporal variation of the gravity field through the continuous gravity records. Our goal was to detect certain geophysical signal on the order of a few tens of micro-Gal from the gravity data sequence. The gravity data sequences were recorded by the Scintrex g-Phone relative gravimeters those were located at the numerous observation stations of mainland China which had well-controlled observation systems. We presented a two-step procedure to study the signal of gravity variation. Firstly, we developed a Linear Similarity filtering technique which could reduce the drift of gravity instrument effectively by using two relative gravimeters at the same station by the reason of the short-term liner drift feature of gravimeters. Based on the method above, we gained non-tidal gravity variation more accurate that contained much geophysical signal which was associated with geodynamical phenomena. Secondly, we employed the time-frequency analysis techniques to analyze the feature of different temporal variation signal and tried to find some periodic and non-periodic characteristics of the continuous gravity data sequence. Moreover, we compared the results to the mobile repeated gravity measurements on ground and acquired the spatial and temporal gravity variation at last. We also expected to find some anomaly signal related to the activities of tectogenesis and fault movement prior to the destructive earthquakes from the continuous gravity data sequence. Acknowledgment: We acknowledge the financial support of the Basic Scientific Research Foundation of Institute of Geophysics CEA (DQJB12B20, DQJB12C03 and DQJB12B14), the Scientific and Technological Support Foundation of CEA (2012BAK19B01-05-02) and the National Natural Science Foundation of China (41104046).

  8. Unsupervised identification of damage and load characteristics in time-varying systems

    NASA Astrophysics Data System (ADS)

    Roveri, N.; Carcaterra, A.

    2015-09-01

    Parameters identification of nonstationary systems is a very challenging topic that has only recently received critical attention from the research community. Aim of the paper is the structural health monitoring of bridge-like structures excited by a massive moving load, whose characteristics, such as the mass and speed, are unknown, in the presence of a localized damage along the structure. A novel method for the simultaneous identification of both the load characteristics and damage parameters from vibration measurements is proposed: the data processing relies on the ensemble empirical mode decomposition and the normalized Hilbert transform. Neither a priori information about the response of the undamaged structure nor the free decay of the damaged system is required, only a single-point measurement is needed. The empirical instantaneous frequency is firstly employed to estimate the load characteristics; secondly, the effect of the moving mass is filtered from the instantaneous frequency, and then, the damage position is identified. The performance of the technique are studied varying the load characteristics, damage locations, and crack depths. The effect of ambient noise is also taken into account. Numerical experiments show the identification is rather accurate, results are not very sensitive to the crack location and depth, while they are sensibly affected by the speed of the moving load.

  9. First Time: Characteristics of Teens' First Sexual Relationships. Child Trends Research Brief.

    ERIC Educational Resources Information Center

    Ryan, Suzanne; Manlove, Jennifer; Franzetta, Kerry

    Understanding characteristics of teens' sexual relationships may help us to better understand how to reduce teens' risk of early unintended pregnancy and sexually transmitted diseases (STDs), as well as the psychological and emotional problems that may be associated with teenage romantic relationships and sexual activity. Using data from the

  10. Are Middle Schools Harmful? The Role of Transition Timing, Classroom Quality and School Characteristics

    ERIC Educational Resources Information Center

    Holas, Igor; Huston, Aletha C.

    2012-01-01

    Are middle schools ill-suited for early adolescents, or can school characteristics account for any differences in student functioning? Achievement, school engagement, and perceived competence of children starting middle schools in 5th and 6th grades were compared to those of their same-grade peers in elementary schools in a national, longitudinal…

  11. Maternal selenium supplementation and timing of nutrient restriction in pregnant sheep: Impacts on maternal endocrine status and placental characteristics.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective was to determine the effects of dietary selenium and nutrient restriction (level and timing) on serum hormone and metabolite levels and placental characteristics in mid- to late-pregnancy ewes. Pregnant ewe lambs (n = 64) were assigned to 1 of 8 treatments arranged in a 2 x 2 x 2 facto...

  12. Direct measurement of the characteristic three-body electron attachment time in the atmospheric air in direct current electric field

    SciTech Connect

    Shutov, A. V.; Smetanin, I. V.; Ionin, A. A.; Levchenko, A. O.; Seleznev, L. V.; Sinitsyn, D. V.; Ustinovskii, N. N.; Zvorykin, V. D.

    2013-07-15

    We report the results of theoretical and experimental study of the characteristic time for three-body attachment of electrons produced by 100 fs UV laser pulse in the atmosphere air in the external DC electric field ranged from 0.2 to 10 kV/cm.

  13. English Learner Student Characteristics and Time to Reclassification: An Example from Washington State. REL 2016-128

    ERIC Educational Resources Information Center

    Greenberg Motamedi, Jason; Singh, Malkeet; Thompson, Karen D.

    2016-01-01

    How long does it typically take English learner students to develop English language proficiency? And how does this time vary by student characteristics such as English proficiency at entry to kindergarten, gender, and home language? The answers to these questions can provide valuable information to districts and schools. Regional Educational…

  14. Experimental observations of direct laminar-turbulent transition in counter-rotating Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Crowley, Christopher; Krygier, Michael; Borrero-Echeverry, Daniel; Grigoriev, Roman; Schatz, Michael

    2015-11-01

    The transition to turbulence in counter-rotating Taylor-Couette flow typically occurs through a sequence of supercritical bifurcations of stable flow states (e.g. spiral vortices, interpenetrating spirals (IPS), and wavy interpenetrating spirals). Coughlin and Marcus have proposed a mechanism by which these laminar spiral flows undergo a secondary instability that leads to turbulence. We report the discovery of a counter-rotating regime (Reout = - 1000 , Rein ~ 640) of small aspect ratio/large radius ratio Taylor-Couette flow (Γ = 5 . 26 / η = 0 . 91), where the system bypasses the primary instability to stable laminar spirals and instead undergoes a direct transition to turbulence as the inner cylinder rotation rate is slowly increased. This transition is mediated by an unstable IPS state. We study the transition experimentally using flow visualization and tomographic PIV, and show that it is both highly repeatable and that it shows hysteresis as the inner cylinder rotation rate is decreased. As Rein is decreased, the turbulent flow relaminarizes into an intermediate, stable IPS state. Decreasing Rein further returns the system back to circular Couette flow. This study was supported by NSF DMS-1125302 and NSF CMMI-1234436.

  15. DNS of laminar/turbulent boundary layer transition induced by solid obstacles

    NASA Astrophysics Data System (ADS)

    Orlandi, Paolo; Bernardini, Matteo; Pirozzoli, Sergio

    2011-11-01

    Direct numerical simulation is used to investigate how boundary layer transition is affected by the shape and size of an isolated obstacle whose size is of the order of the boundary layer thickness. The Navier-Stokes equations are discretized by means of an energy-conserving second-order staggered finite-difference method, and the geometrical complexity associated with the obstacle is handled through the immersed-boundary technique. A series of simulations have been performed by varying: i) the obstacle shape (cylinders and prisms with rectangular and triangular base); ii) the roughness height (as a fraction of the boundary layer thickness); iii) the width of the obstacle; iv) the Reynolds number of the incoming boundary layer. We have monitored the vorticity dynamics of the structures which are shed past the obstacle, and observed the concurrence of two mechanisms which promote transition to turbulence, namely the unsteady shear layer separation at the top edge of the obstacle, and the regeneration of quasi-streamwise vortices at the sides of the obstacle. The validity of semi-empirical transition criteria based on a suitably defined roughness Reynolds number will also be discussed, and associated with the physical mechanisms responsible for the self-sustainment of the disturbances. The computational resources to perform the study were provided by CINECA.

  16. Infrared thermography for detection of laminar-turbulent transition in low-speed wind tunnel testing

    NASA Astrophysics Data System (ADS)

    Joseph, Liselle A.; Borgoltz, Aurelien; Devenport, William

    2016-05-01

    This work presents the details of a system for experimentally identifying laminar-to-turbulent transition using infrared thermography applied to large, metal models in low-speed wind tunnel tests. Key elements of the transition detection system include infrared cameras with sensitivity in the 7.5- to 14.0-µm spectral range and a thin, insulating coat for the model. The fidelity of the system was validated through experiments on two wind-turbine blade airfoil sections tested at Reynolds numbers between Re = 1.5 × 106 and 3 × 106. Results compare well with measurements from surface pressure distributions and stethoscope observations. However, the infrared-based system provides data over a much broader range of conditions and locations on the model. This paper chronicles the design, implementation and validation of the infrared transition detection system, a subject which has not been widely detailed in the literature to date.

  17. Laminar, turbulent, and inertial shear-thickening regimes in channel flow of neutrally buoyant particle suspensions.

    PubMed

    Lashgari, Iman; Picano, Francesco; Breugem, Wim-Paul; Brandt, Luca

    2014-12-19

    The aim of this Letter is to characterize the flow regimes of suspensions of finite-size rigid particles in a viscous fluid at finite inertia. We explore the system behavior as a function of the particle volume fraction and the Reynolds number (the ratio of flow and particle inertia to viscous forces). Unlike single-phase flows, where a clear distinction exists between the laminar and the turbulent states, three different regimes can be identified in the presence of a particulate phase, with smooth transitions between them. At low volume fractions, the flow becomes turbulent when increasing the Reynolds number, transitioning from the laminar regime dominated by viscous forces to the turbulent regime characterized by enhanced momentum transport by turbulent eddies. At larger volume fractions, we identify a new regime characterized by an even larger increase of the wall friction. The wall friction increases with the Reynolds number (inertial effects) while the turbulent transport is weakly affected, as in a state of intense inertial shear thickening. This state may prevent the transition to a fully turbulent regime at arbitrary high speed of the flow. PMID:25554885

  18. Experimental study of the laminar-turbulent transition of a concave wall in a parallel flow

    NASA Technical Reports Server (NTRS)

    Bippes, H.

    1978-01-01

    The instability of the laminar boundary layer flow along a concave wall was studied. Observations of these three-dimensional boundary layer phenomena were made using the hydrogen-bubble visualization technique. With the application of stereo-photogrammetric methods in the air-water system it was possible to investigate the flow processes qualitatively and quantitatively. In the case of a concave wall of sufficient curvature, a primary instability occurs first in the form of Goertler vortices with wave lengths depending upon the boundary layer thickness and the wall curvature. At the onset the amplification rate is in agreement with the linear theory. Later, during the non-linear amplification stage, periodic spanwise vorticity concentrations develop in the low velocity region between the longitudinal vortices. Then a meandering motion of the longitudinal vortex streets subsequently ensues, leading to turbulence.

  19. Numerical investigation of direct laminar-turbulent transition in counter-rotating Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Krygier, Michael; Grigoriev, Roman

    2015-11-01

    A direct transition from laminar to turbulent flow has recently been discovered experimentally in the small-gap Taylor-Couette flow with counter-rotating cylinders. The subcritical nature of this transition is a result of relatively small aspect ratio, Γ = 5 . 26 for large Γ the transition is supercritical and involves an intermediate stable state (Coughlin & Marcus, 1996) - interpenetrating spirals (IPS). We investigate this transition numerically to probe the dynamics in regimes inaccessible to experiments for a fixed Reo = - 1000 by varying Rei . The numerics reproduce all the experimentally observed features and confirm the hysteretic nature of the transition. As Rei is increased, the laminar flow transitions to turbulence, with an unstable IPS state mediating the transition, similar to the Tollmien-Schlichting waves in plane Poiseuille flow. As Rei is decreased, turbulent flow transitions to a stable, temporally chaotic IPS state. This IPS state further transitions to either laminar or turbulent flow as Rei is decreased or increased. The stable IPS state is reminiscent of the pre-turbulent chaotic states found numerically in plane Poiseuille flow (Zammert & Eckhardt, 2015), but previously never observed experimentally.

  20. Numerical investigation of laminar-turbulent transition in a flat plate wake

    NASA Technical Reports Server (NTRS)

    Fasel, Hermann F.; Newell, Alan C.; Dratler, David I.

    1990-01-01

    Lamina-turbulent transition of high-deficit flat plate wakes is investigated by direct numerical simulations using the complete Navier Stokes equations. The simulations are based on a spatial model so that both the base flow and the disturbance flow can develop in the downstream direction. The Navier Stokes equations are used in a vorticity-velocity form and are solved using a combination of finite difference and spectral approximations. Fourier series are used in the spanwise direction. Second-order finite-differences are used to approximate the spatial derivatives in the streamwise and transverse directions. For the temporal discretion, a combination of ADI, Crank-Nicolson, and Adams-Bashforth methods is employed. The discretized velocity equations are solved using fast Helmholtz solvers. Code validation is accomplished by comparison of the numerical results to both linear stability and to experiments. Calculations of two- and/or three-dimensional sinuous and mode disturbances in the wake of flat plate are undertaken. For calculations of two-dimensional disturbances, the wake is forced at an amplitude level so that nonlinear disturbance development may be observed. In addition, the forcing amplitude is varied in order to determine its effect on the disturbance behavior. To investigate the onset of three-dimensionality, the wake is forced with a small-amplitude three-dimensional disturbance and a larger amplitude two-dimensional disturbance. The two-dimensional forcing amplitude is varied in order to determine its influence on the three-dimensional flow field.

  1. On role of kinetic fluctuations in laminar-turbulent transition in chemically nonequilibrium boundary layer flows

    NASA Astrophysics Data System (ADS)

    Tumin, Anatoli

    2015-11-01

    Zavol'skii and Reutov (1983), Luchini (2008, 2010), Fedorov (2010, 2012, 2014) explored potential role of kinetic fluctuations (KF) in incompressible and calorically perfect gas boundary layer flows. The results indicate that role of KF is comparable with other disturbance sources in flight experiments and in quiet wind tunnels. The analysis is based on the Landau and Lifshitz (1957) concept of fluctuating hydrodynamics representing the dissipative fluxes as an average and fluctuating parts. We are extending analysis of the receptivity problem to the fluctuating dissipative fluxes in chemically reacting nonequilibrium boundary layer flows of binary mixtures. There are new terms in the energy, and the species equations. The species conservation equation includes the dissipative diffusion flux and the species generation due to dissociation. The momentum equation includes fluctuating stress tensor. The energy equation includes fluctuating heat flux, energy flux due to diffusion of the species, and fluctuating dissipative flux due to viscosity. The effects are compared for the cases stemming from constraints of the HTV project (Klentzman and Tumin, AIAA Paper 2013-2882). Supported by AFOSR.

  2. DNS of Laminar-Turbulent Transition in Swept-Wing Boundary Layers

    NASA Technical Reports Server (NTRS)

    Duan, L.; Choudhari, M.; Li, F.

    2014-01-01

    Direct numerical simulation (DNS) is performed to examine laminar to turbulent transition due to high-frequency secondary instability of stationary crossflow vortices in a subsonic swept-wing boundary layer for a realistic natural-laminar-flow airfoil configuration. The secondary instability is introduced via inflow forcing and the mode selected for forcing corresponds to the most amplified secondary instability mode that, in this case, derives a majority of its growth from energy production mechanisms associated with the wall-normal shear of the stationary basic state. An inlet boundary condition is carefully designed to allow for accurate injection of instability wave modes and minimize acoustic reflections at numerical boundaries. Nonlinear parabolized stability equation (PSE) predictions compare well with the DNS in terms of modal amplitudes and modal shape during the strongly nonlinear phase of the secondary instability mode. During the transition process, the skin friction coefficient rises rather rapidly and the wall-shear distribution shows a sawtooth pattern that is analogous to the previously documented surface flow visualizations of transition due to stationary crossflow instability. Fully turbulent features are observed in the downstream region of the flow.

  3. Large-Eddy Simulation of Laminar-Turbulent Transition in a Swept-Wing Boundary Layer

    NASA Technical Reports Server (NTRS)

    Huai, X.; Joslin, R. D.; Piomelli, U.

    2004-01-01

    A continuous adjoint approach for obtaining sensitivity derivatives on unstructured grids is developed and analyzed. The derivation of the costate equations is presented, and a second-order accurate discretization method is described. The relationship between the continuous formulation and a discrete formulation is explored for inviscid, as well as for viscous flow. Several limitations in a strict adherence to the continuous approach are uncovered, and an approach that circumvents these difficulties is presented. The issue of grid sensitivities, which do not arise naturally in the continuous formulation, is investigated and is observed to be of importance when dealing with geometric singularities. A method is described for modifying inviscid and viscous meshes during the design cycle to accommodate changes in the surface shape. The accuracy of the sensitivity derivatives is established by comparing with finite-difference gradients and several design examples are presented.

  4. Selective Influence of Circadian Modulation and Task Characteristics on Motor Imagery Time

    ERIC Educational Resources Information Center

    Debarnot, Ursula; Sahraoui, Djafar; Champely, Stephane; Collet, Christian; Guillot, Aymeric

    2012-01-01

    In this study, we examined the effect of circadian modulation on motor imagery (MI) time while also considering the effects of task complexity and duration. The ability to imagine in real time was influenced by circadian modulation in a simple walking condition, with longer MI times in the morning and evening sessions. By contrast, there was no…

  5. Selective Influence of Circadian Modulation and Task Characteristics on Motor Imagery Time

    ERIC Educational Resources Information Center

    Debarnot, Ursula; Sahraoui, Djafar; Champely, Stephane; Collet, Christian; Guillot, Aymeric

    2012-01-01

    In this study, we examined the effect of circadian modulation on motor imagery (MI) time while also considering the effects of task complexity and duration. The ability to imagine in real time was influenced by circadian modulation in a simple walking condition, with longer MI times in the morning and evening sessions. By contrast, there was no

  6. Are middle schools harmful? The role of transition timing, classroom quality and school characteristics.

    PubMed

    Holas, Igor; Huston, Aletha C

    2012-03-01

    Are middle schools ill-suited for early adolescents, or can school characteristics account for any differences in student functioning? Achievement, school engagement, and perceived competence of children starting middle schools in 5th and 6th grades were compared to those of their same-grade peers in elementary schools in a national, longitudinal sample (NICHD Study of Early Child Care and Youth Development, n = 855; 52% Female, 82% White). Classroom quality (observed and teacher-reported) and school characteristics (composition and size) were considered as explanations for any relationships between school-level and student functioning. Fifth grade middle school students did not differ from those in elementary school, but students entering middle school in 6th grade, compared to those in elementary school, experienced lower classroom quality, which in turn predicted slightly lower achievement. They also had lower school engagement, explained by larger school size. Classroom quality and school characteristics predicted youth functioning regardless of school type. We suggest reshaping the research and policy debate with renewed focus on classroom quality and school size instead of grade organization. PMID:22143392

  7. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    SciTech Connect

    Paeng, Dongwoo; Grigoropoulos, Costas P.; Lee, Daeho

    2014-08-18

    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  8. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    NASA Astrophysics Data System (ADS)

    Paeng, Dongwoo; Lee, Daeho; Grigoropoulos, Costas P.

    2014-08-01

    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  9. Characteristic of Carbon Nanotubes Prepared from Fermented Glutinous Rice with Different Incubation Times

    NASA Astrophysics Data System (ADS)

    Nik, S. F.; Zainal, N. F. A.; Azira, A.; Rusop, M.

    2009-06-01

    Fermented glutinous rice prepared at different incubation time was prepared and used as a starting material in CNTs synthesis using 2-system thermal chemical vapor deposition (TCVD) method. The preparation of fermented glutinous rice was adapted from traditional process, with some alteration and assessment of the effects of incubation time in the fermentation process. The incubation period was fluctuated from 2 to 10 days of time. The CNTs was deposited on nickel coated silicon where the nickel acts as catalyst in the growth process. The prepared CNTs were analyzed using fourier transformation infrared spectroscopy (FTIR) to determine the chemical properties in the sample. The CNTs were structurally characterized using scanning electron microscopy (SEM) at different magnification to see the differences of CNTs growth at different incubation time of the starting material. The results suggested that favorable CNTs structures can be obtained at short time of incubation period, in which the CNTs sized increases with the augmentation of incubation time.

  10. The Effects of Family Characteristics and Time Use on Teenagers' Household Labor.

    ERIC Educational Resources Information Center

    Gager, Constance T.; Cooney, Teresa M.; Call, Kathleen Thiede

    1999-01-01

    Longitudinal data collected from teenagers were analyzed for types of household chores the teens perform. The study determined that girls devoted more time to household tasks than boys, while both their efforts were greater in larger families and single-parent families. High school males spent more time on extracurricular and leisure activities,…

  11. Correlation Analyses Between the Characteristic Times of Gradual Solar Energetic Particle Events and the Properties of Associated Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Pan, Z. H.; Wang, C. B.; Wang, Yuming; Xue, X. H.

    2011-06-01

    It is generally believed that gradual solar energetic particles (SEPs) are accelerated by shocks associated with coronal mass ejections (CMEs). Using an ice-cream cone model, the radial speed and angular width of 95 CMEs associated with SEP events during 1998 - 2002 are calculated from SOHO/LASCO observations. Then, we investigate the relationships between the kinematic properties of these CMEs and the characteristic times of the intensity-time profile of their accompanied SEP events observed at 1 AU. These characteristic times of SEP are i) the onset time from the accompanying CME eruption at the Sun to the SEP arrival at 1 AU, ii) the rise time from the SEP onset to the time when the SEP intensity is one-half of peak intensity, and iii) the duration over which the SEP intensity is within a factor of two of the peak intensity. It is found that the onset time has neither significant correlation with the radial speed nor with the angular width of the accompanying CME. For events that are poorly connected to the Earth, the SEP rise time and duration have no significant correlation with the radial speed and angular width of the associated CMEs. However, for events that are magnetically well connected to the Earth, the SEP rise time and duration have significantly positive correlations with the radial speed and angular width of the associated CMEs. This indicates that a CME event with wider angular width and higher speed may more easily drive a strong and wide shock near to the Earth-connected interplanetary magnetic field lines, may trap and accelerate particles for a longer time, and may lead to longer rise time and duration of the ensuing SEP event.

  12. Space-Time Characteristic Functions in Multivariate Logic and Possible Interpretation of Entanglement

    NASA Astrophysics Data System (ADS)

    Gaudeau de Gerlicz, Claude; Sechpine, Pierre; Bobola, Philippe; Antoine, Mathias

    The knowledge about hidden variables in physics, (Bohr's-Schrödinger theories) and their developments, boundaries seem more and more fuzzy at physical scales. Also some other new theories give to both time and space as much fuzziness. The classical theory, (school of Copenhagen's) and also Heisenberg and Louis de Broglie give us the idea of a dual wave and particle parts such the way we observe. Thus, the Pondichery interpretation recently developed by Cramer and al. gives to the time part this duality. According Cramer, there could be a little more to this duality, some late or advanced waves of time that have been confirmed and admitted as possible solutions with the Maxwell's equations. We developed here a possible pattern that could matched in the sequence between Space and both retarded and advanced time wave in the "Cramer handshake" in locality of the present when the observation is made everything become local.

  13. Characteristics of Storm-time Electric Fields in the Inner Magnetosphere Derived From Cluster Data

    NASA Astrophysics Data System (ADS)

    Matsui, H.; Puhl-Quinn, P. A.; Jordanova, V. K.; Khotyaintsev, Y.; Lindqvist, P.; Torbert, R. B.

    2008-12-01

    We report storm-time electric fields in the inner magnetosphere at L=4-10 and full magnetic local time measured by Cluster. Here we use merged data from the Electron Drift Instrument (EDI) and the Electric Field and Wave (EFW) instrument. Data are analyzed statistically by picking storm periods during March 2001 and November 2007. Superposed epoch analysis with an epoch at Dst minimum is performed to reveal dependence of electric fields on epoch time and spacecraft locations. Strong electric fields are detected right around the Dst minimum for all magnetic local times, even though the data acquisition rate is not always large during these periods. The magnitude of electric fields often increases as L value decreases, although this is not always the case. The data are further examined in terms of the location of the inner edge of plasmasheet electrons and controlling parameters such as geomagnetic indices and interplanetary parameters.

  14. Leisure Time of Young Due to Some Socio-Demographic Characteristics

    ERIC Educational Resources Information Center

    Ðuranovic, Marina; Opic, Siniša

    2014-01-01

    The aim of this paper is to explore the prevalence of activities in leisure time of the young. A survey was conducted on 1062 students in 8 primary (n=505; 47,6%) and high schools (n=557; 52,4%) in Sisak - Moslavina County in the Republic of Croatia. The questionnaire of spending leisure time used was made up of 30 variables on a five-degree scale…

  15. Muscle Activation Characteristics of the Front Leg During Baseball Swings with Timing Correction for Sudden Velocity Decrease

    PubMed Central

    Ohta, Yoichi; Nakamoto, Hiroki; Ishii, Yasumitsu; Ikudome, Sachi; Takahashi, Kyohei; Shima, Norihiro

    2015-01-01

    This study aimed to clarify the activation characteristics of the vastus lateralis muscle in the front leg during timing correction for a sudden decrease in the velocity of a target during baseball swings. Eleven male collegiate baseball players performed coincident timing tasks that comprised constant velocity of 8 m/s (unchanged) and a sudden decrease in velocity from 8 to 4 m/s (decreased velocity). Electromyography (EMG) revealed that the muscle activation was typically monophasic when responding unchanged conditions. The type of muscle activation during swings in response to decreased velocity condition was both monophasic and biphasic. When biphasic activation appeared in response to decreased velocity, the impact time and the time to peak EMG amplitude were significantly prolonged and the timing error was significantly smaller than that of monophasic activation. However, the EMG onset from the target start was consistent both monophasic and biphasic activation in response to conditions of decreased velocity. In addition, batters with small timing errors in response to decreased velocity were more likely to generate biphasic EMG activation. These findings indicated that timing correction for a sudden decrease in the velocity of an oncoming target is achieved by modifying the muscle activation characteristics of the vastus lateralis muscle of front leg from monophasic to biphasic to delay reaching peak muscle activation and thus prolong impact time. Therefore, the present findings suggests that the extent of timing errors in response to decreased velocity is influenced by the ability to correct muscle activation after its initiation rather than by delaying the initiation timing of muscle activation during baseball swings. PMID:25918848

  16. Investigation of doped calcium aluminosilicate glass: A coupling between thermal-expansion and thermal-diffusion models for assessment of nonradiative relaxation time and characteristic diffusion time

    NASA Astrophysics Data System (ADS)

    Souza Filho, N. E.; Nogueira, A. C.; Rohling, J. H.; Baesso, M. L.; Medina, A. N.; Siqueira, A. P. L.; Sampaio, J. A.; Vargas, H.; Bento, A. C.

    2009-11-01

    This paper discusses the use of photoacoustic models to obtain the nonradiative relaxation time (τ) and characteristic diffusion time (τβ) for a sample showing visible absorption bands from fluorescent ion-doped low-silica calcium aluminosilicate glass. Two models allowing phase shift analyses, the thermal-expansion and thermal-diffusion models, are briefly reviewed. These models have limitations when the photoacoustic signal depends on both factors, in a coupling mechanism. An alternative model is proposed to take both thermal expansion and thermal diffusion into account with a single temperature solution for the heat-coupled differential equation. This model is simulated for absorbing samples near the thermally thick region. The model is applied to Eu-V codoped glass showing intermediate signal dependence from ω-1.0 to ω-3/2. The nonradiative time and characteristic diffusion time are derived with 33<τ(ms)<39, and τβ(ms)˜70 ms for the Eu-ion and 340<τβ(ms)<710 for the V-ion. Four absorption bands were analyzed (280, 350, 420, and 600 nm), which showed a signal dependence from ω-1.1 to ω-1.52. Absorption coefficients were derived from τβ in the range of 15<β(cm-1)<51, which agreed fairly well with spectrophotometer data for the same ions.

  17. Time-domain diffuse optical tomography using analytic statistical characteristics of photon trajectories

    SciTech Connect

    Konovalov, Aleksandr B; Vlasov, V V; Kalintsev, A G; Lyubimov, Vladimir V; Kravtsenyuk, Olga V

    2006-11-30

    The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions. (special issue devoted to multiple radiation scattering in random media)

  18. Correlation of Biological Characteristics of Smolts with Survival and Travel Time, 1987 Technical Report.

    SciTech Connect

    Rondorf, Dennis W.; Beeman, John W.; Free, Mary E.

    1988-06-01

    The biological characteristics of smolts were examined to determine their effect on estimates of survival in the Columbia and Snake rivers. Freeze branded groups of steelhead trout (Salmo gairdneri) from Lyons Ferry State Fish Hatchery (SFH) and Wells SFH and spring chinook salmon (Oncorhynchus tshawytscha) from Winthrop National Fish Hatchery (NFH) were used to estimate survival. Past estimates of survival, using a ratio of test and control fish recaptured at McNary Dam, have resulted in estimates > 100%, presumably due to some unknown bias. Study objectives were to determine if stress and descaling, degree of smoltification, and prevalence of bacterial kidney disease (BKD) differed among test and control groups of fish, thereby biasing survival estimates. 19 refs., 20 figs., 10 tabs.

  19. Physical nature of empirical dependences of strength and fracture characteristics of materials on time

    NASA Astrophysics Data System (ADS)

    Krasovskij, A. Ya.; Tot, L.

    1994-06-01

    A correlation is established between each of two empirical relationship parameters describing the arrays of the experimental data on long-term strength, creep, high- and low-cycle fatigue, and fatigue crack propagation for tungsten, molybdenum, titanium alloys, and steels. Unambiguous relationships between the parameters within each array allow the required scope of the material testing to be reduced appreciably. The physical essence of the correlations revealed is related to a thermally activated nature of damage processes, which accompany each type of material testing. It is shown that for all types of tests considered it is possible to define the character of dependence between the correlating empirical parameters and fundamental characteristics of thermally activated damage processes.

  20. Characteristics of the Time Variable Component of the Coronal Heating Process

    NASA Technical Reports Server (NTRS)

    Habbal, Shadia R.; Poland, Art (Technical Monitor)

    2001-01-01

    The goal of the proposed study was to explore the non-steady nature of the coronal heating processes and its manifestations in the inner corona and interplanetary space by coordinating coronal SOHO observations in white light, ultraviolet, and extreme ultraviolet, with complementary radio occultation measurements during an unprecedented and rare coincidence of a total solar eclipse with the superior conjunction of a planetary spacecraft, Galileo, in February 1998. In addition, radio occultation measurements by the Mars Global Surveyor spacecraft in May 1998 spanned the inner heliosphere observed by coronal SOHO instruments and probing it to within 0.5 R(sub S), above the solar surface. Inferences of physical properties derived from these simultaneous observations were subsequently used in solar wind model computations to yield the range of plasma parameters characteristic of the fast and slow solar wind.

  1. Hydrological connectivity of hillslopes and streams: Characteristic time scales and nonlinearities

    NASA Astrophysics Data System (ADS)

    McGuire, Kevin J.; McDonnell, Jeffrey J.

    2010-10-01

    Subsurface flow from hillslopes is widely recognized as an important contributor to streamflow generation; however, processes that control how and when hillslopes connect to streams remain unclear. We investigated stream and hillslope runoff dynamics through a wet-up period in watershed 10 of the H. J. Andrews Experimental Forest in the western Cascades of Oregon where the riparian zone has been removed by debris flows. We examined the controls on hillslope-stream connectivity on the basis of observations of hydrometric, stable isotope, and applied tracer responses and computed transit times for multiple runoff components for a series of storms during the wet-up phase of the 2002-2003 winter rainy season. Hillslope discharge was distinctly threshold-like with a near linear response and average quick flow ratio of 0.58 when antecedent rainfall was greater than 20 mm. Hillslope and stream stormflow varied temporally and showed strong hysteretic relationships. Event water mean transit times (8-34 h) and rapid breakthrough from applied hillslope tracer additions demonstrated that subsurface contributing areas extend far upslope during events. Despite rapid hillslope transport processes during events, soil water and runoff mean transit times during nonstorm conditions were greater than the time scale of storm events. Soil water mean transit times ranged between 10 and 25 days. Hillslope seepage and catchment base flow mean transit times were between 1 and 2 years. We describe a conceptual model that captures variable physical flow pathways, their synchronicity, threshold activation, hysteresis, and transit times through changing antecedent wetness conditions that illustrate the different stages of hillslope and stream connectivity.

  2. Characteristics of fluctuating space-time geometries---Minkowski and Schwarzschild examples

    NASA Astrophysics Data System (ADS)

    Thompson, Robert T.

    Space-time geometry fluctuations are expected to be a generic feature of a successful theory of quantum gravity. Despite the lack of such a theory, it is still possible to explore the physical implications of space-time fluctuations. The techniques employed are gauge invariant---being based on the Riemann tensor correlation function. Two scenarios will be discussed within the semiclassical theory of General Relativity. In the first, the space-time is taken to be nearly Minkowskian on average. Fluctuations are induced by the presence of either a linearized quantum graviton field or a thermal bath of gravitons, and are characterized by fluctuations in the trajectory or flight time of null rays traversing the fluctuating space-time from a distant source to an observer. The observable manifestation of these fluctuations are a blurring of the angular position of the source or a broadening of the spectral line of the source. It is shown that these effects are quite small and are likely not observable. In the second scenario under investigation, the space-time is taken to be Schwarzschild on average and the context is that of an evaporating black hole. Fluctuations of the horizon are induced through three models of ingoing quantum fields---a "scalar graviton" model that is a conformal transformation of the metric where the conformal factor is a scalar field, a linearized graviton model, and a scalar field stress tensor model. Fluctuations to the space-time are characterized by fluctuations in the squared length of a vector used to describe the deviation of outgoing null geodesics near the horizon and what effect these fluctuations could have on Hawking radiation. It is shown that fractional fluctuations of the squared length of the separation vector may be of order one, concordant with results obtained by previous authors in somewhat different contexts. Furthermore, it is found that the Hawking process appears to be very robust against these types of fluctuations.

  3. Characteristics of zinc sulphide nanostructures grown onsilica modified-polyaniline with polymerization time-dependent

    NASA Astrophysics Data System (ADS)

    Potestas, M.; Alguno, A.; Vequizo, R.; Sambo, B. R.; Odarve, M. K.

    2015-06-01

    Growth of zinc sulphide (ZnS) nanostructures on silica modified-polyaniline (SM- PAni) with polymerization time-dependent was prepared using chemical bath deposition (CBD) technique. The grown samples were characterized by scanning electron microscopy (SEM) equipped with energy dispersive x-ray spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR). SEM images revealed that polyaniline rod-like nanostructures and ZnS nanospheres were successfully grown. The average diameter of the grown ZnS nanospheres did not significantly change by changing the growth time of the polyaniline. However, ZnS nanospheres grown with longer polymerization time of PAni is less dense and loosely bound as compared to shorter polymerization time of PAni. The less density of ZnS nanostructures with longer polymerization time of PAni may be due to the presence of PAni agglomerates that hinders the growth of ZnS nanospheres. Furthermore, FTIR spectra confirmed that the grown polyaniline is of emeraldine salt oxidation state which is the most conductive state of PAni.

  4. Characteristics and control response of the TOPAZ II Reactor System Real-time Dynamic Simulator

    SciTech Connect

    Kwok, K.S.

    1993-11-12

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

  5. Time-frequency integration characteristics of hearing are optimized for perception of speech-like acoustic patterns.

    PubMed

    Räsänen, Okko; Laine, Unto K

    2013-07-01

    Several psychoacoustic phenomena such as loudness perception, absolute thresholds of hearing, and perceptual grouping in time are affected by temporal integration of the signal in the auditory system. Similarly, the frequency resolution of the hearing system, often expressed in terms of critical bands, implies signal integration across neighboring frequencies. Although progress has been made in understanding the neurophysiological mechanisms behind these processes, the underlying reasons for the observed integration characteristics have remained poorly understood. The current work proposes that the temporal and spectral integration are a result of a system optimized for pattern detection from ecologically relevant acoustic inputs. This argument is supported by a simulation where the average time-frequency structure of speech that is derived from a large set of speech signals shows a good match to the time-frequency characteristics of the human auditory system. The results also suggest that the observed integration characteristics are learnable from acoustic inputs of the auditory environment using a Hebbian-like learning rule. PMID:23862817

  6. Impact of real-time traffic characteristics on freeway crash occurrence: systematic review and meta-analysis.

    PubMed

    Roshandel, Saman; Zheng, Zuduo; Washington, Simon

    2015-06-01

    The development of methods for real-time crash prediction as a function of current or recent traffic and roadway conditions is gaining increasing attention in the literature. Numerous studies have modeled the relationships between traffic characteristics and crash occurrence, and significant progress has been made. Given the accumulated evidence on this topic and the lack of an articulate summary of research status, challenges, and opportunities, there is an urgent need to scientifically review these studies and to synthesize the existing state-of-the-art knowledge. This paper addresses this need by undertaking a systematic literature review to identify current knowledge, challenges, and opportunities, and then conducts a meta-analysis of existing studies to provide a summary impact of traffic characteristics on crash occurrence. Sensitivity analyses were conducted to assess quality, publication bias, and outlier bias of the various studies; and the time intervals used to measure traffic characteristics were also considered. As a result of this comprehensive and systematic review, issues in study designs, traffic and crash data, and model development and validation are discussed. Outcomes of this study are intended to provide researchers focused on real-time crash prediction with greater insight into the modeling of this important but extremely challenging safety issue. PMID:25841161

  7. Taekwondo Techniques and Competition Characteristics Involved in Time-Loss Injuries

    PubMed Central

    Beis, Konstantinos; Pieter, Willy; Abatzides, George

    2007-01-01

    The purpose of this study was to assess time-loss injuries in young and adult taekwondo athletes. Participants were 2739 children (11-13 years), Junior (14-17 years) and adult males and females (18 years and older) competing in the national Greek championships. Injury data were collected by project staff with all diagnoses made by the tournament physician. Odds ratios were computed as well as 95% confidence intervals around the injury rates. The female Juniors had a higher time-loss injury rate (Fisher’s Exact Test p = 0.033) than their adult counterparts. However, they were not at a higher risk of incurring a time-loss injury: OR = 0.143, 95% CI: 0.018-1.124. Collapsed over age, the females as a group recorded more time-loss injuries [11.36/1,000 A-E (95% CI: 6.25-16.47) versus 7.40/1,000 A-E (95% CI: 4.44-10.36)], but this was not significant (OR = 0.703, 95% CI: 0.383-1.293). In the Juniors, the boys only incurred time-loss injuries to the head and neck. There was no difference in the Junior girls in the distribution of time-loss injuries across body region, although they were at higher risk of sustaining an injury to the head and neck (OR = 1.510, 95% CI: 0.422-5.402) but this was not statistically significant. Although there were no statistical differences among age groups within gender, the Junior boys and girls (11-13 years) sustained more cerebral concussions. The Junior boys were at a higher risk of incurring a cerebral concussion than the boys (OR = 7.871, 95% CI: 0.917-67.583, Fisher’s Exact Test p = 0.036). In the males, there was no difference between the men and Junior boys in injury rate for swing kicks compared to other techniques (OR = 2.000, 95% CI = 0.397-28.416). There also was no difference between the men and boys (OR = 4.800, 95% CI: 0.141-58.013). To help reduce the incidence of time-loss injuries in taekwondo, especially cerebral concussions, it is suggested for coaches to emphasize blocking skills. Educating referees, coaches and athletes plays an important role in helping to reduce taekwondo time-loss injuries. Key points The purpose of this study was to assess time-loss injuries in young and adult taekwondo athletes. Collapsed over age, the females as a group recorded more time-loss injuries but this was not significant. The Junior boys were at a higher risk of incurring a cerebral concussion than the boys. To help reduce the incidence of time-loss injuries in taekwondo, especially cerebral concussions, it is suggested for coaches to emphasize blocking skills. Educating referees, coaches and athletes plays an important role in helping to reduce taekwondo time-loss injuries. PMID:24198703

  8. Taekwondo techniques and competition characteristics involved in time-loss injuries.

    PubMed

    Beis, Konstantinos; Pieter, Willy; Abatzides, George

    2007-01-01

    The purpose of this study was to assess time-loss injuries in young and adult taekwondo athletes. Participants were 2739 children (11-13 years), Junior (14-17 years) and adult males and females (18 years and older) competing in the national Greek championships. Injury data were collected by project staff with all diagnoses made by the tournament physician. Odds ratios were computed as well as 95% confidence intervals around the injury rates. The female Juniors had a higher time-loss injury rate (Fisher's Exact Test p = 0.033) than their adult counterparts. However, they were not at a higher risk of incurring a time-loss injury: OR = 0.143, 95% CI: 0.018-1.124. Collapsed over age, the females as a group recorded more time-loss injuries [11.36/1,000 A-E (95% CI: 6.25-16.47) versus 7.40/1,000 A-E (95% CI: 4.44-10.36)], but this was not significant (OR = 0.703, 95% CI: 0.383-1.293). In the Juniors, the boys only incurred time-loss injuries to the head and neck. There was no difference in the Junior girls in the distribution of time-loss injuries across body region, although they were at higher risk of sustaining an injury to the head and neck (OR = 1.510, 95% CI: 0.422-5.402) but this was not statistically significant. Although there were no statistical differences among age groups within gender, the Junior boys and girls (11-13 years) sustained more cerebral concussions. The Junior boys were at a higher risk of incurring a cerebral concussion than the boys (OR = 7.871, 95% CI: 0.917-67.583, Fisher's Exact Test p = 0.036). In the males, there was no difference between the men and Junior boys in injury rate for swing kicks compared to other techniques (OR = 2.000, 95% CI = 0.397-28.416). There also was no difference between the men and boys (OR = 4.800, 95% CI: 0.141-58.013). To help reduce the incidence of time-loss injuries in taekwondo, especially cerebral concussions, it is suggested for coaches to emphasize blocking skills. Educating referees, coaches and athletes plays an important role in helping to reduce taekwondo time-loss injuries. Key pointsThe purpose of this study was to assess time-loss injuries in young and adult taekwondo athletes.Collapsed over age, the females as a group recorded more time-loss injuries but this was not significant.The Junior boys were at a higher risk of incurring a cerebral concussion than the boys.To help reduce the incidence of time-loss injuries in taekwondo, especially cerebral concussions, it is suggested for coaches to emphasize blocking skills.Educating referees, coaches and athletes plays an important role in helping to reduce taekwondo time-loss injuries. PMID:24198703

  9. Effect of reaction time on the characteristics of catalytically grown boron nitride nanotubes

    SciTech Connect

    Mohamed, Norani Muti E-mail: pervaiz-pas@yahoo.com E-mail: zainabh@petronas.com.my; Ahmad, Pervaiz E-mail: pervaiz-pas@yahoo.com E-mail: zainabh@petronas.com.my; Saheed, Mohamed Shuaib Mohamed E-mail: pervaiz-pas@yahoo.com E-mail: zainabh@petronas.com.my; Burhanudin, Zainal Arif E-mail: pervaiz-pas@yahoo.com E-mail: zainabh@petronas.com.my

    2014-10-24

    The paper reports on the growth of boron nitride nanotube (BNNTs) on Si substrate by catalytic chemical vapor deposition technique and the effect of reaction time and temperature on the size and purity were investigated. Scanning electron microscopy image revealed the bamboo-like BNNTs of multiwalled type with interlayer spacing of 0.34 nm. EDX analysis described the presence of a small percentage of Mg in the sample, indicating the combination of base-tip growth model for the sample synthesized at 1200°C. The reaction time has an effect of extending the length of the BNNTs until the catalyst is oxidized or covered by growth precursor.

  10. Effect of reaction time on the characteristics of catalytically grown boron nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Mohamed, Norani Muti; Ahmad, Pervaiz; Saheed, Mohamed Shuaib Mohamed; Burhanudin, Zainal Arif

    2014-10-01

    The paper reports on the growth of boron nitride nanotube (BNNTs) on Si substrate by catalytic chemical vapor deposition technique and the effect of reaction time and temperature on the size and purity were investigated. Scanning electron microscopy image revealed the bamboo-like BNNTs of multiwalled type with interlayer spacing of 0.34 nm. EDX analysis described the presence of a small percentage of Mg in the sample, indicating the combination of base-tip growth model for the sample synthesized at 1200°C. The reaction time has an effect of extending the length of the BNNTs until the catalyst is oxidized or covered by growth precursor.

  11. Comparison of characteristic times for satellite absorption of energetic protons trapped in the Jovian and Saturnian magnetic fields

    SciTech Connect

    Hood, L.L.

    1981-09-01

    The relative symmetry of the Saturnian magnetic field with respect to the rotational equatorial plane results in characteristic times for satellite absorption of trapped energetic protons that are typically one to three orders of magnitude smaller than the corresponding Jovian satellite absorption times. The maximum difference occurs for nearly equatorially mirroring particles. Assuming that the rates of radial diffusion are comparable within the two magnetospheres, the inner Saturnian satellites are more efficient absorbers of inwardly diffusing ions than their Jovian counterparts. Thus, via the mechanism of satellite absorption, the rotational symmetry of the planetary magnetic field may play an important indirect role in determining gross properties of the radiation environment at Saturn.

  12. Effect of different egg storage times on some egg quality characteristics and hatchability of pheasants (Phasianus colchicus).

    PubMed

    Demirel, S; Kirikçi, K

    2009-02-01

    In this study, some quality characteristics and hatchability characteristics of 1 to 2, 3 to 4, 5 to 6, 7 to 8, 9 to 10, 11 to 12, and 13 to 14 d stored pheasant eggs were investigated. Although it was determined that the effect of storage time on egg weight, shape index, and albumen weight was not significant, the effect of storage time on eggshell weight, shell thickness, yolk weight, albumen index, yolk index, Haugh unit, shell percentage, albumen percentage, and yolk percentage was significant (P<0.05). It was determined that prolonged storage time caused a decrease in the albumen index and Haugh unit value but an increase in the yolk index of pheasant eggs. There was no positive or negative effect of storage time on the fertility rates and hatchability of fertile eggs, but there was a negative effect of storage time on hatchability on d 8 (P<0.05). Pheasant eggs should not be stored more than 8 d. PMID:19151360

  13. Characteristic recovery times of Forbush-type decreases in the cosmic radiation. I - Observations at earth at different energies

    NASA Technical Reports Server (NTRS)

    Lockwood, J. A.; Webber, W. R.; Jokipii, J. R.

    1986-01-01

    Data on 30 asymmetric Forbush decreases recorded by the IMP spacecraft at 1 AU and the Mt. Washington neutron monitor over the period 1972-84 are examined to characterize the recovery characteristics of cosmic rays after the events. The spacecraft data are concentrated at energies of 1.7 GV, while the terrestrial instruments recorded events at 5 GV. Attention is paid to the relative amplitudes of the recorded transient decreases, the characteristic recovery times, and the energy dependence of the amplitudes and recovery time. The recovery times were found to be equal at both energy levels, supporting a concept of energy independence for the recoveries. Also, no correlations were found between the recovery times and the occurrences of a solar magnetic field reversal or with phase in the solar modulation cycle. A time-dependent, two-dimensional model is defined, which expresses the cosmic ray particle distributions as a function of the decay of the disturbance, with a small dependence on the transport parameters of the cosmic rays.

  14. Temporal Characteristics of the Predictive Synchronous Firing Modeled by Spike-Timing-Dependent Plasticity

    ERIC Educational Resources Information Center

    Kitano, Katsunori; Fukai, Tomoki

    2004-01-01

    When a sensory cue was repeatedly followed by a behavioral event with fixed delays, pairs of premotor and primary motor neurons showed significant increases of coincident spikes at times a monkey was expecting the event. These results provided evidence that neuronal firing synchrony has predictive power. To elucidate the underlying mechanism, here

  15. Characteristics of Disfluency Clusters over Time in Preschool Children Who Stutter

    ERIC Educational Resources Information Center

    Sawyer, Jean; Yairi, Ehud

    2010-01-01

    Purpose: Disfluency clusters in preschool children were analyzed to determine whether they occurred at rates above chance, whether they changed over time, and whether they could differentiate children who would later persist in, or recover from, stuttering. Method: Thirty-two children recruited near stuttering onset were grouped on the basis of…

  16. An Investigation of the Erosion in New Major Innovation Characteristics over Time

    ERIC Educational Resources Information Center

    O'Donnell, Joseph B.; Sauer, Paul L.

    2009-01-01

    A recent study by O'Donnell and Sauer (2008) indicated, that over time, the benefit of launching new majors to reduce freshman attrition dissipated. In 2004, new majors had a significant effect on reducing attrition. By 2007, however, these same new majors were no longer significant predictors of attrition. What happened between 2004 and 2007 to…

  17. Temporal Characteristics of the Predictive Synchronous Firing Modeled by Spike-Timing-Dependent Plasticity

    ERIC Educational Resources Information Center

    Kitano, Katsunori; Fukai, Tomoki

    2004-01-01

    When a sensory cue was repeatedly followed by a behavioral event with fixed delays, pairs of premotor and primary motor neurons showed significant increases of coincident spikes at times a monkey was expecting the event. These results provided evidence that neuronal firing synchrony has predictive power. To elucidate the underlying mechanism, here…

  18. A characteristic space-time conservation element and solution element method for conservation laws

    NASA Astrophysics Data System (ADS)

    Shen, Hua; Wen, Chih-Yung; Zhang, De-Liang

    2015-05-01

    In this paper, an upwind space-time conservation element and solution element (CE/SE) method is developed to solve conservation laws. In the present method, the mesh quantity and spatial derivatives are the independent marching variables, which is consistent with the original CE/SE method proposed by Chang (1995) [5]. The staggered time marching strategy and the definition of conservation element (CE) also follow Chang's propositions. Nevertheless, the definition of solution element (SE) is modified from that of Chang. The numerical flux through the interface of two different conservation elements is not directly derived by a Taylor expansion in the reversed time direction as proposed by Chang, but determined by an upwind procedure. This modification does not change the local and global conservative features of the original method. Although, the time marching scheme of mesh variables is the same with the original method, the upwind fluxes are involved in the calculation of spatial derivatives, yielding a totally different approach from that of Chang's method. The upwind procedure breaks the space-time inversion invariance of the original scheme, so that the new scheme can be directly applied to capture discontinuities without spurious oscillations. In addition, the present method maintains low dissipation in a wide range of CFL number (from 10-6 to 1). Furthermore, we extend the upwind CE/SE method to solve the Euler equations by adopting three different approximate Riemann solvers including Harten, Lax and van Leer (HLL) Riemann solver, contact discontinuity restoring HLLC Riemann solver and mathematically rigorous Roe Riemann solver. Extensive numerical examples are carried out to demonstrate the robustness of the present method. The numerical results show that the new CE/SE solvers perform improved resolutions.

  19. Vocal characteristics of pygmy blue whales and their change over time.

    PubMed

    Gavrilov, Alexander N; McCauley, Robert D; Salgado-Kent, Chandra; Tripovich, Joy; Burton, Chris

    2011-12-01

    Vocal characteristics of pygmy blue whales of the eastern Indian Ocean population were analyzed using data from a hydroacoustic station deployed off Cape Leeuwin in Western Australia as part of the Comprehensive Nuclear-Test-Ban Treaty monitoring network, from two acoustic observatories of the Australian Integrated Marine Observing System, and from individual sea noise loggers deployed in the Perth Canyon. These data have been collected from 2002 to 2010, inclusively. It is shown that the themes of pygmy blue whale songs consist of ether three or two repeating tonal sounds with harmonics. The most intense sound of the tonal theme was estimated to correspond to a source level of 179 ± 2 dB re 1 μPa at 1 m measured for 120 calls from seven different animals. Short-duration calls of impulsive downswept sound from pygmy blue whales were weaker with the source level estimated to vary between 168 to 176 dB. A gradual decrease in the call frequency with a mean rate estimated to be 0.35 ± 0.3 Hz/year was observed over nine years in the frequency of the third harmonic of tonal sound 2 in the whale song theme, which corresponds to a negative trend of about 0.12 Hz/year in the call fundamental frequency. PMID:22225022

  20. Effect of extraction time and temperature on the characteristics of loosely bound pectins from Japanese plum.

    PubMed

    Basanta, Mara F; Ponce, Nora M A; Rojas, Ana M; Stortz, Carlos A

    2012-06-01

    The cell wall composition of Japanese plums (Prunus salicina) at six developmental stages was previously evaluated (Ponce et al., J. Agric. Food Chem. 2010, 58, 2562-2570). This fruit is an interesting source of pectins, polysaccharides of valuable functionality for pharmaceutical and food formulations. In the present work it was investigated how the different conditions for the aqueous extraction of pectins from Japanese plums affect the yield as well as their chemical and rheological characteristics. It has been determined that extraction with water at room temperature for periods longer than 2h did not produce additional increment of yield (12%) but decreased the average molecular weights of the extracted pectins. Pectins with a degree of methylation ?40% with high viscosity in water and with adequate molecular weights (?72,000) were obtained. Conversely, utilization of boiling water for extraction increased considerably the yields (33-38%) but the extracted pectins showed significant lower viscosity in water in spite of their higher molecular weights. The poorer thickening ability was associated to the lower proportion of arabinose residues present in the hairy regions of the pectin macromolecules extracted by hot water, which led the polymers to interact more transiently in a 2% w/v water solution. PMID:24750628

  1. Deformation characteristics and time-dependent notch sensitivity of Udimet 700 at intermediate temperatures

    NASA Technical Reports Server (NTRS)

    Wilson, D. J.

    1974-01-01

    Time dependent notch sensitivity was observed in Udimet 700 sheet, bar, and investment castings between 1000 and 1400 F (538 -760 C), but not at 1600 F (871 C). As was the case for modified Waspaloy, Waspaloy and Inconel 718, it occurred in notched specimens loaded below the yield strength when the creep deformation was localized. For each alloy and notched specimen geometry, a stress-average particle size zone can be defined that characterizes the notch sensitive behavior.

  2. Spectral characteristics of time-dependent orbit errors in altimeter height measurements

    NASA Technical Reports Server (NTRS)

    Chelton, Dudley B.; Schlax, Michael G.

    1993-01-01

    A mean reference surface and time-dependent orbit errors are estimated simultaneously for each exact-repeat ground track from the first two years of Geosat sea level estimates based on the Goddard Earth model (GEM)-T2 orbits. Motivated by orbit theory and empirical analysis of Geosat data, the time-dependent orbit errors are modeled as 1 cycle per revolution (cpr) sinusoids with slowly varying amplitude and phase. The method recovers the known 'bow tie effect' introduced by the existence of force model errors within the precision orbit determination (POD) procedure used to generate the GEM-T2 orbits. The bow tie pattern of 1-cpr orbit errors is characterized by small amplitudes near the middle and larger amplitudes (up to 160 cm in the 2 yr of data considered here) near the ends of each 5- to 6-day orbit arc over which the POD force model is integrated. A detailed examination of these bow tie patterns reveals the existence of daily modulations of the amplitudes of the 1-cpr sinusoid orbit errors with typical and maximum peak-to-peak ranges of about 14 cm and 30 cm, respectively. The method also identifies a daily variation in the mean orbit error with typical and maximum peak-to-peak ranges of about 6 and 30 cm, respectively, that is unrelated to the predominant 1-cpr orbit error. Application of the simultaneous solution method to the much less accurate Geosat height estimates based on the Naval Astronautics Group orbits concludes that the accuracy of POD is not important for collinear altimetric studies of time-dependent mesoscale variability (wavelengths shorter than 1000 km), as long as the time-dependent orbit errors are dominated by 1-cpr variability and a long-arc (several orbital periods) orbit error estimation scheme such as that presented here is used.

  3. Time- and spectrally resolved characteristics of flavin fluorescence in U87MG cancer cells in culture

    NASA Astrophysics Data System (ADS)

    Horilova, Julia; Cunderlikova, Beata; Marcek Chorvatova, Alzbeta

    2015-05-01

    Early detection of cancer is crucial for the successful diagnostics of its presence and its subsequent treatment. To improve cancer detection, we tested the progressive multimodal optical imaging of U87MG cells in culture. A combination of steady-state spectroscopic methods with the time-resolved approach provides a new insight into the native metabolism when focused on endogenous tissue fluorescence. In this contribution, we evaluated the metabolic state of living U87MG cancer cells in culture by means of endogenous flavin fluorescence. Confocal microscopy and time-resolved fluorescence imaging were employed to gather spectrally and time-resolved images of the flavin fluorescence. We observed that flavin fluorescence in U87MG cells was predominantly localized outside the cell nucleus in mitochondria, while exhibiting a spectral maximum under 500 nm and fluorescence lifetimes under 1.4 ns, suggesting the presence of bound flavins. In some cells, flavin fluorescence was also detected inside the cell nuclei in the nucleoli, exhibiting longer fluorescence lifetimes and a red-shifted spectral maximum, pointing to the presence of free flavin. Extra-nuclear flavin fluorescence was diminished by 2-deoxyglucose, but failed to increase with 2,4-dinitrophenol, the uncoupler of oxidative phosphorylation, indicating that the cells use glycolysis, rather than oxidative phosphorylation for functioning. These gathered data are the first step toward monitoring the metabolic state of U87MG cancer cells.

  4. Extracting concrete thermal characteristics from temperature time history of RC column exposed to standard fire.

    PubMed

    Kim, Jung J; Youm, Kwang-Soo; Reda Taha, Mahmoud M

    2014-01-01

    A numerical method to identify thermal conductivity from time history of one-dimensional temperature variations in thermal unsteady-state is proposed. The numerical method considers the change of specific heat and thermal conductivity with respect to temperature. Fire test of reinforced concrete (RC) columns was conducted using a standard fire to obtain time history of temperature variations in the column section. A thermal equilibrium model in unsteady-state condition was developed. The thermal conductivity of concrete was then determined by optimizing the numerical solution of the model to meet the observed time history of temperature variations. The determined thermal conductivity with respect to temperature was then verified against standard thermal conductivity measurements of concrete bricks. It is concluded that the proposed method can be used to conservatively estimate thermal conductivity of concrete for design purpose. Finally, the thermal radiation properties of concrete for the RC column were estimated from the thermal equilibrium at the surface of the column. The radiant heat transfer ratio of concrete representing absorptivity to emissivity ratio of concrete during fire was evaluated and is suggested as a concrete criterion that can be used in fire safety assessment. PMID:25180197

  5. Grip strength characteristics using force-time curves in rheumatoid hands.

    PubMed

    Dias, J J; Singh, H P; Taub, Nick; Thompson, J

    2013-02-01

    The use of force-time curves in rheumatoid hands was investigated to assess peak force, average force, total grip time, area under the curve, and variability of the plateau region of the curves to identify the impact of different rheumatoid hand deformities on grip strength. We studied 43 patients - 10 men and 33 women - with established rheumatoid arthritis affecting their hands. Mean age was 61 years and mean duration of hand involvement was 13 years. Of the 86 hands, 38 had no finger deformity, eight had metacarpophalangeal joint ulnar deviation without any additional finger deformities, 16 had swan neck deformities, and 10 had boutonnire deformities. Fourteen hands had a combination of deformities. The hands with combined deformities were the weakest, had poor grip strength (34.7 N, SE 8), and were able to sustain grip for only a short time (22 sec, SE 3). Swan neck deformity also profoundly affects the magnitude (49.8 N, SE 7) and sustainability of grip (15 sec, SE 2). Even when only one finger had a swan neck deformity the mean strength was poor at 45 N. Swan neck deformity causes greater loss of strength than boutonnire deformity (82.7 N, SE 15). The strongest rheumatoid hands were those with only ulnar deviation deformities (90.8 N, SE 14). The area under the curve best predicted disability assessed using the Patient Evaluation Measure. PMID:22357327

  6. Structural, morphological and electrical characteristics of electrodeposited Cu2O: Effect of deposition time

    NASA Astrophysics Data System (ADS)

    Messaoudi, O.; assaker, I. Ben; Gannouni, M.; Souissi, A.; Makhlouf, H.; Bardaoui, A.; Chtourou, R.

    2016-03-01

    In this work, a new contribution to the knowledge of thickness (or deposition time) dependence of structural, morphological and optical properties is reported, as well as the electrochemical behavior of the Cu2O electrode/(NaOH) electrolyte solution interface. According to these studies, X-ray diffraction revealed that all films are mainly crystallized in Cu2O cubic phase characterized by the preferential orientation along (1 1 1) plane. Optical measurements show that both values of reflectance and film thickness increase when increasing the deposition time, unlike the band gap energy which decreases with time. Using the electrochemical impedance spectroscopy data, the interface was modeled as an equivalent circuit approach. From the Mott-Schottky measurements, the flat-band potential and the acceptor density for the Cu2O thin films are determined. All the films showed a p-type semiconductor character with a carrier density varying between 0.949 × 1017 cm-3 and 6 × 1017 cm-3.

  7. High power impulse magnetron sputtering: Current-voltage-time characteristics indicate the onset of sustained self-sputtering

    NASA Astrophysics Data System (ADS)

    Anders, André; Andersson, Joakim; Ehiasarian, Arutiun

    2007-12-01

    The commonly used current-voltage characteristics are found inadequate for describing the pulsed nature of the high power impulse magnetron sputtering (HIPIMS) discharge; rather, the description needs to be expanded to current-voltage-time characteristics for each initial gas pressure. Using different target materials (Cu, Ti, Nb, C, W, Al, and Cr) and a pulsed constant-voltage supply, it is shown that the HIPIMS discharges typically exhibit an initial pressure dependent current peak followed by a second phase that is power and material dependent. This suggests that the initial phase of a HIPIMS discharge pulse is dominated by gas ions, whereas the later phase has a strong contribution from self-sputtering. For some materials, the discharge switches into a mode of sustained self-sputtering. The very large differences between materials cannot be ascribed to the different sputter yields but they indicate that generation and trapping of secondary electrons play a major role for current-voltage-time characteristics. In particular, it is argued that the sustained self-sputtering phase is associated with the generation of multiply charged ions because only they can cause potential emission of secondary electrons, whereas the yield caused by singly charged metal ions is negligibly small.

  8. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    PubMed

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff. PMID:26710649

  9. Time-Structured and Net Intraindividual Variability: Tools for Examining the Development of Dynamic Characteristics and Processes

    PubMed Central

    Ram, Nilam; Gerstorf, Denis

    2009-01-01

    The study of intraindividual variability is the study of fluctuations, oscillations, adaptations, and “noise” in behavioral outcomes that manifest on micro-time scales. This paper provides a descriptive frame for the combined study of intraindividual variability and aging/development. At the conceptual level, we highlight that the study of intraindividual variability provides access to dynamic characteristics – construct-level descriptions of individuals' capacities for change (e.g., lability), and dynamic processes – the systematic changes individuals' exhibit in response to endogenous and exogenous influences (e.g., regulation). At the methodological level, we review how quantifications of net intraindividual variability (e.g., iSD) and models of time-structured intraindividual variability (e.g., time-series) are being used to measure and describe dynamic characteristics and processes. At the research design level, we point to the benefits of measurement burst study designs, wherein data are obtained across multiple time scales, for the study of development. PMID:20025395

  10. Performance characteristics of a chemical imaging time-of-flight mass spectrometer.

    PubMed

    Braun, R M; Blenkinsopp, P; Mullock, S J; Corlett, C; Willey, K F; Vickerman, J C; Winograd, N

    1998-01-01

    A chemical imaging time-of-flight secondary ion mass spectrometer is described. It consists of a liquid metal ion gun, medium energy resolution reflectron mass analyzer, liquid nitrogen cooled sample stage, preparation chamber and dual stage entry port. Unique features include compatibility with laser postionization experiments, large field of view, cryogenic sample handling capability and high incident ion beam current. Instrument performance is illustrated by the characterization of scanning electron microscopy grids, silver and functionalized polystyrene beads and the postionization of an organic overlayer on a gold substrate. PMID:9772767

  11. Deformation characteristics and time-dependent notch sensitivity of Udimet 700 at intermediate temperatures

    NASA Technical Reports Server (NTRS)

    Wilson, D. J.

    1975-01-01

    Time-dependent notch sensitivity of Udimet 700 sheet, bar, and investment castings was observed between 1000 and 1400 F (538-760 C) but not at 1600 F (871 C). As was the case for Modified Waspaloy, Waspaloy, Rene 41, Inconel 718, and TD-NiCr, it occurred when notched specimens were loaded below the yield strength and when creep deformation was localized. For each gamma-prime strengthened alloy and notched specimen geometry, a stress-average particle size zone can be defined to characterize the notch-sensitive behavior.

  12. Characteristics of chiral and racemic ketoprofen drugs using terahertz time-domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Du, Yong; Liu, Jianjun; Hong, Zhi

    2013-08-01

    Absorption spectra of chiral S-(+)- and racemic RS-ketoprofen pharmaceutical molecules in crystalline form were recorded in the terahertz region between 6 and 66 cm-1 (0.2 ~ 2.0 THz) by using time-domain terahertz spectroscopic (THz-TDS) measurement. Different distinctive absorption features were observed which are strikingly sensitive to the change of subtle conformational structures within such isostructural crystal molecules. The results suggest that the THz-TDS technique can be definitely used for distinguishing between chiral and racemic compounds in pharmaceutical and biological fields.

  13. An event based real-time conditioned predictor of hourly hyetograph characteristics

    NASA Astrophysics Data System (ADS)

    Giorgio, Massimiliano; Greco, Roberto

    2010-05-01

    Setting up stochastic models capable to perform real-time conditioned rainfall predictions at high temporal resolution is crucial in developing hydro-geological early warning systems. Indeed, several rainfall-induced dangerous phenomena taking place at catchment or slope scale, such as flash floods and debris flows, may be triggered by relatively short rainfall events. The small spatial resolution at which the predictions are needed does not allow to make use neither of rainfall forecasts based on global circulation models, nor of data coming from radar sensors. Thus, the most reliable source of information is still represented by rain gauges installed at the site to be monitored. Modelling of point rainfall series has been addressed in hydrological literature with two major approaches: cluster-based models and event-based models. In this paper, using rainfall data observed in real time during a storm, a stochastic predictor of its future evolution is presented. The core of the predictor consists in an event based stochastic model. An event based approach is adopted, since it permits to identify a storm on the basis of the observed series of rainfall data and to calculate univocally its probability, thus allowing to perform the desired predictions in a relatively straightforward way. With this approach, predictions can be conditioned only to the part of real time observed rainfall data on which future evolution of the storm depends, in the stochastic sense. Conversely, cluster-based stochastic models, widely used for the generation of synthetic rainfall series, are not trivially suitable for real-time conditioned predictions, since they do not allow to evaluate unambiguously the probability of an observed hyetograph, because it can be generated by more than one combination of rain cells. The proposed model has been calibrated with hourly rainfall series of the rain gauges of the meteorological alert network of the Civil Protection Agency of Campania, Southern Italy. The statistical hypotheses on which the model is based have been checked by classical statistical tests, such as Blum-Kiefer-Rosenblatt test for independence. Furthermore, the information about the observed internal structure of the storm, at hourly scale, has been coupled with the external structure model, allowing to perform conditioned predictions of hydrologic response indexes, depending on the future evolution of hyetograph shape.

  14. Aerodynamics of cyclist posture, bicycle and helmet characteristics in time trial stage.

    PubMed

    Chabroux, Vincent; Barelle, Caroline; Favier, Daniel

    2012-07-01

    The present work is focused on the aerodynamic study of different parameters, including both the posture of a cyclist's upper limbs and the saddle position, in time trial (TT) stages. The aerodynamic influence of a TT helmet large visor is also quantified as a function of the helmet inclination. Experiments conducted in a wind tunnel on nine professional cyclists provided drag force and frontal area measurements to determine the drag force coefficient. Data statistical analysis clearly shows that the hands positioning on shifters and the elbows joined together are significantly reducing the cyclist drag force. Concerning the saddle position, the drag force is shown to be significantly increased (about 3%) when the saddle is raised. The usual helmet inclination appears to be the inclination value minimizing the drag force. Moreover, the addition of a large visor on the helmet is shown to provide a drag coefficient reduction as a function of the helmet inclination. Present results indicate that variations in the TT cyclist posture, the saddle position and the helmet visor can produce a significant gain in time (up to 2.2%) during stages. PMID:22084053

  15. Analog memory and spike-timing-dependent plasticity characteristics of a nanoscale titanium oxide bilayer resistive switching device.

    PubMed

    Seo, Kyungah; Kim, Insung; Jung, Seungjae; Jo, Minseok; Park, Sangsu; Park, Jubong; Shin, Jungho; Biju, Kuyyadi P; Kong, Jaemin; Lee, Kwanghee; Lee, Byounghun; Hwang, Hyunsang

    2011-06-24

    We demonstrated analog memory, synaptic plasticity, and a spike-timing-dependent plasticity (STDP) function with a nanoscale titanium oxide bilayer resistive switching device with a simple fabrication process and good yield uniformity. We confirmed the multilevel conductance and analog memory characteristics as well as the uniformity and separated states for the accuracy of conductance change. Finally, STDP and a biological triple model were analyzed to demonstrate the potential of titanium oxide bilayer resistive switching device as synapses in neuromorphic devices. By developing a simple resistive switching device that can emulate a synaptic function, the unique characteristics of synapses in the brain, e.g. combined memory and computing in one synapse and adaptation to the outside environment, were successfully demonstrated in a solid state device. PMID:21572200

  16. Analog memory and spike-timing-dependent plasticity characteristics of a nanoscale titanium oxide bilayer resistive switching device

    NASA Astrophysics Data System (ADS)

    Seo, Kyungah; Kim, Insung; Jung, Seungjae; Jo, Minseok; Park, Sangsu; Park, Jubong; Shin, Jungho; Biju, Kuyyadi P.; Kong, Jaemin; Lee, Kwanghee; Lee, Byounghun; Hwang, Hyunsang

    2011-06-01

    We demonstrated analog memory, synaptic plasticity, and a spike-timing-dependent plasticity (STDP) function with a nanoscale titanium oxide bilayer resistive switching device with a simple fabrication process and good yield uniformity. We confirmed the multilevel conductance and analog memory characteristics as well as the uniformity and separated states for the accuracy of conductance change. Finally, STDP and a biological triple model were analyzed to demonstrate the potential of titanium oxide bilayer resistive switching device as synapses in neuromorphic devices. By developing a simple resistive switching device that can emulate a synaptic function, the unique characteristics of synapses in the brain, e.g. combined memory and computing in one synapse and adaptation to the outside environment, were successfully demonstrated in a solid state device.

  17. The internal clock: evidence for a temporal oscillator underlying time perception with some estimates of its characteristic frequency.

    PubMed

    Treisman, M; Faulkner, A; Naish, P L; Brogan, D

    1990-01-01

    Evidence for the proposition that human time perception is determined by an internal clock is largely indirect. It would strengthen the case for this hypothesis if a model for the internal clock were available from which predictions could be derived and tested, and if the basic parameter of such a model, the frequency at which the clock runs, could be estimated. A model for an internal temporal pacemaker is briefly described and its properties are explored by computer simulation. Results are obtained that provide a basis for predicting that, under appropriate conditions, interference between an imposed rhythm and the frequency of a temporal oscillator may cause perturbations in temporal judgment which are related to the characteristic frequency of that oscillator. Experimental data are reported which appear to demonstrate such an interference pattern. These results allow some estimates of the characteristic frequency of the temporal oscillator to be obtained. PMID:2130371

  18. Storage characteristics, nutritive value, and fermentation characteristics of alfalfa packaged in large-round bales and wrapped in stretch film after extended time delays.

    PubMed

    Coblentz, W K; Coffey, K P; Chow, E A

    2016-05-01

    The production of baled silage is attractive to producers because it offers advantages over dry hay, particularly by limiting risks associated with wet or unstable weather conditions. Our objectives were to test the effects of delayed wrapping on silage fermentation, storage characteristics, and the nutritive value of baled alfalfa silages. To accomplish this, large-round bales of alfalfa were wrapped in plastic film within 4h of baling (d 0), or after delays of 1, 2, or 3 d. A secondary objective was to evaluate a prototype bale wrap containing an O2-limiting barrier (OB) against an identical polyethylene wrap without the O2 barrier (SUN). Sixty-four 1.19×1.25-m bales of alfalfa were made from 4 field blocks at a mean moisture concentration of 59.1±4.3% with a mean initial wet bale weight of 473±26.4kg. Two bales per field block were assigned to each combination of bale wrap (SUN or OB) and wrapping time (0, 1, 2, or 3 d postbaling), and one bale of each pair was fitted with a thermocouple placed in the geometric center of each bale. All bales were sampled after a 97-d storage period. Internal bale temperatures, recorded at the time bales were wrapped, were greater for all bales with wrapping delays compared with bales wrapped on d 0 (54.9 vs. 34.9°C), and increased to a maximum of 63.9°C after a 3-d delay exhibiting a linear effect of time delay. Total silage fermentation acids (lactic, acetic, propionic, butyric, and isobutyric) were greatest when bales were wrapped on d 0 compared with all bales wrapped with time delays (4.64 vs. 2.26% of DM), and declined with linear and quadratic effects of wrapping delay. Total fermentation acids also were related quadratically to internal bale temperature by regression [y (% of DM)=0.0042x(2) - 0.50x + 17.1; R(2)=0.725]. Similar responses were observed for lactic acid, except that trends were linear, both for orthogonal contrasts evaluating length of wrapping delay, and in regressions on internal bale temperature [y (% of DM)=-0.046x + 3.5; R(2)=0.663]. Butyric acid also was detected, regardless of treatment, but was greatest within bales wrapped on d 0 compared with those with wrapping delays (0.99 vs. 0.38% of DM), and a similar response (0.68 vs. 0.52% of DM) was observed for NH3-N, suggesting that clostridial activity occurred during silage fermentation. Based on these results, silage fermentation characteristics and the nutritive value declined with time delays before wrapping, but responses were exacerbated when delays exceeded 1 d. PMID:26923055

  19. Structure dependence of oscillation characteristics of resonant-tunneling-diode terahertz oscillators associated with intrinsic and extrinsic delay times

    NASA Astrophysics Data System (ADS)

    Kanaya, Hidetoshi; Maekawa, Takeru; Suzuki, Safumi; Asada, Masahiro

    2015-09-01

    We investigate the effect of intrinsic and extrinsic delay times on the oscillation characteristics of resonant-tunneling-diode (RTD) terahertz oscillators. The intrinsic delay time is composed of the electron dwell time in the resonant tunneling region and the electron transit time in the collector depletion region. We obtain and discuss the structure dependence of these factors in terms of the oscillation frequency and output power measured for RTD oscillators with different quantum-well and collector-spacer thicknesses and different air-bridge widths between the RTD and a slot antenna. The highest oscillation frequency achieved in this experiment is 1.86 THz for the well and spacer thicknesses of 2.5 and 12 nm, respectively, with a 1-µm-wide air bridge. In this structure, the extrinsic delay time (80 fs) estimated from the parasitic elements is more than double the intrinsic delay time (35 fs). It is shown theoretically that an oscillation frequency of over 2 THz is possible upon the reduction in the extrinsic delay time caused by the bulk and spread resistances in RTDs.

  20. Search for characteristic features of low-energy quiet-time H, He and heavy nuclei fluxes, 1973-1977

    NASA Technical Reports Server (NTRS)

    Mason, G. M.; Gloeckler, G.; Hovestadt, D.

    1980-01-01

    Results of a survey of the 0.5-10 MeV/nucleon fluxes of H, He and heavier ions during interplanetary 'quiet-times' over the period 1973-1977 using the ULET telescope on IMP-8 are reported. It is found that in this energy range no characteristic flux level, or, e.g., proton/alpha ratio emerges during quiet periods in any year, thus precluding systematic long-term studies of the time behavior of the quiet-time component at these energies. Spectra for a uniquely quiet period in May 1977 and a less restrictively chosen set of quiet periods in 1976-1977 are presented and compared with previous results.

  1. Conformational characteristics of chiral and racemic naproxen molecules investigated by terahertz time-domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Du, Yong; Zhao, Rongjiao; Hao, Guohui; Guo, Changsheng; Hong, Zhi

    2011-11-01

    Absorption spectra in the terahertz region between 6 and 66 cm-1 (0.2 ~ 2.0 THz) were measured for S-(+)-, R-(-) and RS-naproxen pharmaceutical molecules in crystalline form using time-domain terahertz spectroscopic (THz-TDS) technique at room temperature. Different absorption features were observed for the racemic RS-naproxen and its corresponding enantiomers (S-(+)- and R-(-)-naproxen). The observed THz absorption bands are strikingly sensitive to the change of subtle conformational structures despite that the isostructurality exists within such crystal molecules. The results show that the THz-TDS technique can be definitely used for distinguishing between chiral and racemic compounds in pharmaceutical and biological fields.

  2. Conformational characteristics of chiral and racemic naproxen molecules investigated by terahertz time-domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Du, Yong; Zhao, Rongjiao; Hao, Guohui; Guo, Changsheng; Hong, Zhi

    2012-03-01

    Absorption spectra in the terahertz region between 6 and 66 cm-1 (0.2 ~ 2.0 THz) were measured for S-(+)-, R-(-) and RS-naproxen pharmaceutical molecules in crystalline form using time-domain terahertz spectroscopic (THz-TDS) technique at room temperature. Different absorption features were observed for the racemic RS-naproxen and its corresponding enantiomers (S-(+)- and R-(-)-naproxen). The observed THz absorption bands are strikingly sensitive to the change of subtle conformational structures despite that the isostructurality exists within such crystal molecules. The results show that the THz-TDS technique can be definitely used for distinguishing between chiral and racemic compounds in pharmaceutical and biological fields.

  3. Fall detection and classifications based on time-scale radar signal characteristics

    NASA Astrophysics Data System (ADS)

    Gadde, Ajay; Amin, Moeness G.; Zhang, Yimin D.; Ahmad, Fauzia

    2014-05-01

    Unattended catastrophic falls result in risk to the lives of elderly. There are growing efforts and rising interest in detecting falls of the aging population, especially those living alone. Radar serves as an effective non-intrusive sensor for detecting human activities. For radar to be effective, it is important to achieve low false alarms, i.e., the system can reliably differentiate between a fall and other human activities. In this paper, we discuss the time-scale based signal analysis of the radar returns from a human target. Reliable features are extracted from the scalogram and are used for fall classifications. The classification results and the advantages of using a wavelet transform are discussed.

  4. Characteristics of Settling Coral Reef Fish Are Related to Recruitment Timing and Success

    PubMed Central

    Rankin, Tauna L.; Sponaugle, Su

    2014-01-01

    Many marine populations exhibit high variability in the recruitment of young into the population. While environmental cycles and oceanography explain some patterns of replenishment, the role of other growth-related processes in influencing settlement and recruitment is less clear. Examination of a 65-mo. time series of recruitment of a common coral reef fish, Stegastes partitus, to the reefs of the upper Florida Keys revealed that during peak recruitment months, settlement stage larvae arriving during dark lunar phases grew faster as larvae and were larger at settlement compared to those settling during the light lunar phases. However, the strength and direction of early trait-mediated selective mortality also varied by settlement lunar phase such that the early life history traits of 2–4 week old recruit survivors that settled across the lunar cycle converged to more similar values. Similarly, within peak settlement periods, early life history traits of settling larvae and selective mortality of recruits varied by the magnitude of the settlement event: larvae settling in larger events had longer PLDs and consequently were larger at settlement than those settling in smaller pulses. Traits also varied by recruitment habitat: recruits surviving in live coral habitat (vs rubble) or areas with higher densities of adult conspecifics were those that were larger at settlement. Reef habitats, especially those with high densities of territorial conspecifics, are more challenging habitats for young fish to occupy and small settlers (due to lower larval growth and/or shorter PLDs) to these habitats have a lower chance of survival than they do in rubble habitats. Settling reef fish are not all equal and the time and location of settlement influences the likelihood that individuals will survive to contribute to the population. PMID:25250964

  5. The relationship between isometric force-time curve characteristics and club head speed in recreational golfers.

    PubMed

    Leary, Brian K; Statler, Jason; Hopkins, Britton; Fitzwater, Rachael; Kesling, Tucker; Lyon, Jacob; Phillips, Brett; Bryner, Randall W; Cormie, Prue; Haff, G Gregory

    2012-10-01

    The primary purpose of the present investigation was to examine the relationships between club head speed, isometric midthigh pull performance, and vertical jump performance in a cohort of recreational golfers. Twelve recreational golfers (age, 20.4 ± 1.0 years; weight, 77.0 ± 9.8 kg; height, 177.8 ± 6.3 cm; body fat, 17.1 ± 7.6%; handicap, 14.5 ± 7.3; experience, 8.9 ± 3.6 years) completed 3 testing sessions: (a) familiarization session and body composition measurements; (b) measurement of force-time curves in the isometric midthigh pull, countermovement, and static vertical jump (SJ); and (c) measurement of club head speed. During sessions 1 and 2, subjects performed 5 countermovement jumps, 5 SJ, and 2 isometric midthigh pulls. Isometric peak force was measured at 30, 50, 90, 100, 200, and 250 milliseconds. Rate of force development was measured among 0-30, 0-50, 0-90, 0-100, 0-200, and 0-250 milliseconds. Peak rate of force development was determined as the highest value in a 10-millisecond sampling windows. During session 3, subjects performed 10 maximal golf swings with a driver to measure club head speed; peak and average club head speed were analyzed across the 10 swings. Golf handicap was moderately correlated with average (r = -0.52, p = 0.04) and maximal club head speed (r = -0.45, p = 0.07). Force at 150 milliseconds during the isomeric midthigh pull test was moderately correlated with average (r = 0.46, p = 0.07) and maximal club head speed (r = 0.47, p = 0.06). Moderate correlations were also found between the rate of force development from 0 to 150 milliseconds and average (r = 0.38, p = 0.11) and maximal club head speed (r = 0.36, p = 0.12). The present findings suggest that the ability to exhibit high ground reaction forces in time frames <200 milliseconds are related to high club head speeds. PMID:22797001

  6. The Impact of Ripening Time on Technological Quality Traits, Chemical Change and Sensory Characteristics of Dry-cured Loin

    PubMed Central

    Seong, Pil Nam; Park, Kyoung Mi; Kang, Geun Ho; Cho, Soo Hyun; Park, Beom Young; Van Ba, Hoa

    2015-01-01

    The effect of ripening time on the technological quality traits, fatty acid compositions and sensory characteristics of dry-cured loin was studied. Pork loins (n = 102) at 24 h post-mortem were used to produce dry-cured loins. The dry-cured loins were assessed at 30, 60, and 90 days of ripening for the aforementioned characteristics. Our results showed that the water activity (aw) decreased (p<0.05) up to 60 days and did not change thereafter. The lipid oxidation and weight loss levels significantly (p<0.05) increased with increased ripening time. The Commission Internationale de l’Eclairage (CIE) L* decreased for 90 days while CIE a* increased for 60 days and did not increase thereafter. More noticeably, the levels of most of unsaturated fatty acids and total polyunsaturated fatty acids significantly decreased as increasing ripening time up to 90 days. The 30 days-ripened loins had lower (p<0.05) color, flavor and overall acceptability scores than the loins ripened for 60 and 90 days, however, no differences in sensory traits occurred between the 60 and 90 day-ripened samples. Based on the results obtained in the present study, it is suggested that the ripening duration between 30 and 60 days could be more appropriate for producing dry-cured loin product with higher quality and economic benefits. PMID:25715685

  7. Time-dependent low-field MRI characteristics of canine blood: an in vitro study.

    PubMed

    Jeong, Jimo; Park, Sangjun; Jeong, Eunseok; Kim, Namsoo; Kim, Minsu; Jung, Yechan; Cho, Youngkwon; Lee, Kichang

    2016-03-01

    This study was conducted to assess time-sensitive magnetic resonance (MR) changes in canine blood using low-field MR. Arterial and venous blood samples were collected from eight healthy beagle dogs. Samples were placed in 5-mL tubes and imaged within 3 hours of collection at 1 day intervals from day 1 to day 30. The following sequences were used: T1-weighted (T1W), T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), short tau inversion recovery (STIR), and T2-star gradient-echo (T2(*)-GRE). Visual comparison of the images revealed that four relatively homogenous blood clots and twelve heterogeneous blood clots developed. The margination of the clot and plasma changed significantly on day 2 and day 13. On day 2, heterogeneous blood clots were differentiated into 2 to 3 signal layers in the T2W, T1W, and especially the STIR images. Hypointense signal layers were also detected in the blood clots in STIR images, which have T2 hypo, FLAIR hypo, and T1 hyper intense signals. In all images, these signal layers remained relatively unchanged until day 13. Overall, the results suggest that hematomas are complex on low-field MRI. Accordingly, it may not be feasible to accurately characterize hemorrhages and predict clot age based on low-field MRI. PMID:27051346

  8. Time-dependent low-field MRI characteristics of canine blood: an in vitro study

    PubMed Central

    Jeong, Jimo; Park, Sangjun; Jeong, Eunseok; Kim, Namsoo; Kim, Minsu; Jung, Yechan; Cho, Youngkwon

    2016-01-01

    This study was conducted to assess time-sensitive magnetic resonance (MR) changes in canine blood using low-field MR. Arterial and venous blood samples were collected from eight healthy beagle dogs. Samples were placed in 5-mL tubes and imaged within 3 hours of collection at 1 day intervals from day 1 to day 30. The following sequences were used: T1-weighted (T1W), T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), short tau inversion recovery (STIR), and T2-star gradient-echo (T2*-GRE). Visual comparison of the images revealed that four relatively homogenous blood clots and twelve heterogeneous blood clots developed. The margination of the clot and plasma changed significantly on day 2 and day 13. On day 2, heterogeneous blood clots were differentiated into 2 to 3 signal layers in the T2W, T1W, and especially the STIR images. Hypointense signal layers were also detected in the blood clots in STIR images, which have T2 hypo, FLAIR hypo, and T1 hyper intense signals. In all images, these signal layers remained relatively unchanged until day 13. Overall, the results suggest that hematomas are complex on low-field MRI. Accordingly, it may not be feasible to accurately characterize hemorrhages and predict clot age based on low-field MRI. PMID:27051346

  9. Use of regression equation of peripheral pulse timing characteristics to predict hypertension in children.

    PubMed

    Foo, J Y A; Wilson, S J; Williams, G R; Harris, M; Cooper, D M

    2005-01-01

    Studies have shown that an increase in arterial stiffening can indicate the presence of cardiovascular diseases like hypertension. Current gold standard in clinical practice is by measuring the blood pressure of patients using a mercury sphygmomanometer. However, the nature of this technique is not suitable for prolonged monitoring. It has been established that pulse wave velocity is a direct measure of arterial stiffening. However, its usefulness is hampered by the absence of techniques to estimate it non-invasively. Pulse transit time (PTT) is a simple and non-intrusive method derived from pulse wave velocity. It has shown its capability in childhood respiratory sleep studies. Recently, regression equations that can predict PTT values for healthy Caucasian children were formulated. However, its usefulness to identify hypertensive children based on mean PTT values has not been investigated. This was a continual study where 3 more Caucasian male children with known clinical hypertension were recruited. Results indicated that the PTT predictive equations are able to identify hypertensive children from their normal counterparts in a significant manner (p<0.05). Hence, PTT can be a useful diagnostic tool in identifying hypertension in children and shows potential to be a non-invasive continual monitor for arterial stiffening. PMID:17281140

  10. Oil Sands Characteristics and Time-Lapse and P-SV Seismic Steam Monitoring, Athabasca, Canada

    NASA Astrophysics Data System (ADS)

    Takahashi, A.; Nakayama, T.; Kashihara, K.; Skinner, L.; Kato, A.

    2008-12-01

    A vast amount of oil sands exists in the Athabasca area, Alberta, Canada. These oil sands consist of bitumen (extra-heavy oil) and unconsolidated sand distributed from surface to a depth of 750 meters. Including conventional crude oil, the total number of proved remaining oil reserves in Canada ranks second place in the world after Saudi Arabia. For the production of bitumen from the reservoir 200 to 500 meters in depth, the Steam Assisted Gravity Drainage (SAGD) method (Steam Injection EOR) has been adopted as bitumen is not movable at original temperatures. It is essential to understand the detailed reservoir distribution and steam chamber development extent for optimizing the field development. Oil sands reservoir characterization is conducted using 3D seismic data acquired in February 2002. Conducting acoustic impedance inversion to improve resolution and subsequent multi-attribute analysis integrating seismic data with well data facilitates an understanding of the detailed reservoir distribution. These analyses enable the basement shale to be imaged, and enables identification to a certain degree of thin shale within the reservoir. Top and bottom depths of the reservoir are estimated in the range of 2.0 meters near the existing wells even in such a complex channel sands environment characterized by abrupt lateral sedimentary facies changes. In March 2006, monitoring 3D seismic data was acquired to delineate steam-affected areas. The 2002 baseline data is used as a reference data and the 2006 monitoring data is calibrated to the 2002 seismic data. Apparent differences in the two 3D seismic data sets with the exception of production related response changes are removed during the calibration process. P-wave and S-wave velocities of oil sands core samples are also measured with various pressures and temperatures, and the laboratory measurement results are then combined to construct a rock physics model used to predict velocity changes induced by steam-injection. The differences of the seismic responses between the time-lapse seismic volumes can be quantitatively explained by P-wave velocity decrease of the oil sands layers due to steam-injection. In addition, the data suggests that a larger area would be influenced by pressure than temperature. We calculate several seismic attributes such as RMS values of amplitude difference, maximum cross correlations, and interval velocity differences. These attributes are integrated by using self-organization maps (SOM) and K-means methods. By this analysis, we are able to distinguish areas of steam chamber growth from transitional and non-affected areas. In addition, 3D P-SV converted-wave processing and analysis are applied on the second 3D data set (recorded with three-component digital sensor). Low Vp/Vs values in the P-SV volume show areas of steam chamber development, and high Vp/Vs values indicate transitional zones. Our analysis of both time-lapse 3D seismic and 3D P-SV data along with the rock physics model can be used to monitor qualitatively and quantitatively the rock property changes of the inter-well reservoir sands in the field.

  11. Time Course and Characteristics of Astrocyte Activation in the Rat Brain after Injury

    PubMed Central

    Lee, Hyun-Ho; Choe, Il-Seung; Kim, Young; Ha, Young-Soo

    2015-01-01

    Objective After injury to the central nervous system (CNS), glial scar tissue is formed in the process of wound healing. This can be is a clinical problem because it interferes with axonal regeneration and functional recovery. It is known that intracellular proteins, including the glial fibrillary acidic protein (GFAP), nestin, and vimentin increase in the astrocytes after an injury to the CNS. By studying the time course and co-expression pattern of these intracellular proteins, this study will attempt to prove that these proteins are involved in the processes of glial scar formation. Methods Twenty-five male Sprague-Dawley rats were used in this study. Bregma of the cerebral cortex, an area was incised with a sharp blade, and perfusion was performed. The expressions of the intracellular proteins were assayed, while the co-localization of the intermediate filament (GFAP, nestin, and vimentin) and A2B5 were examined. Results At 12 hours, the GFAP was expressed in the white matter underlying the lesion, and in the cerebral cortex. Nestin was expressed in the astrocytes in the perilesional area after 3 days, while A2B5 was observed in the edge of the wound at 12 hours post-injury, with its expression reaching a peak at 7 days. Vimentin was detected in the white matter at 12 hours, and in the cortex, reaching a peak at 7 days. Conclusion In the processes of glial scar formation, nestin, vimentin, and A2B5 were revealed in the astrocytes, and these factors may be involved in the division, proliferation, and transportation of the astrocytes.

  12. Multifractal characteristics of NDVI maps in space and time in the Community of Madrid (Spain)

    NASA Astrophysics Data System (ADS)

    Sotoca, Juan J. Martin; Saa-Requejo, Antonio; Grau, Juan B.; Tarquis, Ana M.

    2015-04-01

    Satellite information has contributed to improve our understanding of the spatial variability of hydro-climatic and ecological processes. Vegetation activity is tightly coupled with climate, hydro-ecological fluxes, and terrain dynamics in river basins at a wide range of space-time scales (Scheuring and Riedi, 1994). Indices of vegetation activity are constructed using satellite information of reflectance of the relevant spectral bands which enhance the contribution of vegetation being Normalized Difference Vegetation Index (NDVI) widely used. How can we study such a complex system? Multifractals and fractals are related techniques mainly used in physics to characterize the scaling behaviour of a system; they differ in that fractals look at the geometry of presence/absence patterns, while multifractals look at the arrangement of quantities such as population or biomass densities (Saravia et al., 2012). Scaling laws are an emergent general feature of ecological systems; they reflect constraints in their organization that can provide tracks about the underlying mechanisms (Solé and Bascompte, 2006). In this work, we have applied these techniques to study the spatial pattern through one year of NDVI maps. A rectangular area that includes the Community of Madrid and part of the surroundings, consisting of 300 x 280 pixels with a resolution of 500 x 500 m2 has been selected and monthly NDVI maps analyzed using the multifractal spectrum and the map of singularities (Cheng and Agterberg, 1996). The results show a cyclical pattern in the multifractal behaviour and singularity points related to river basin networks (Martín-Sotoca, 2014). References Cheng, Q. and Agterberg, F.P. (1996). Multifractal modeling and spatial statistics. Math. Geol. Vol 28, 1-16. Martín-Sotoca, J.J. (2014) Estructura Espacial de la Sequía en Pastos y sus Aplicaciones en el Seguro Agrario. Master Thesis, UPM (In Spanish). Saravia LA, Giorgi A, Momo F.: Multifractal growth in periphyton communities. Oikos. 2012;121(11):1810-1820 10.1111/j.1600-0706.2011.20423.x Scheuring, I., Riedi, R.H., 1994. Application of multifractals to the analysis of vegetation pattern. J. Veg. Sci. 5, 489-496. Solé RV, Bascompte J.: Self-organization in complex ecosystems. Princeton University Press,2006. Acknowledgements First author acknowledges the Research Grant obtained from CEIGRAM in 2014

  13. Study of the hydrodynamic characteristics of hillslope epikarst zone by means of combined time series analysis and field investigation

    NASA Astrophysics Data System (ADS)

    Zhang, Z.-c.

    2012-04-01

    The karst fracture network in the shallow layer of rock is connected and infiltrated water flows out in a lower area of hillslope. Spring discharge from epikarst zone is an important groundwater resource in karst areas. It is popularly used for irrigation and in the hilly mountainous areas in the southwest karst region of China, about 73% of the southwest karst center area of Guizhou province, China. The different epikarst spring hydrographs derive from a response to diffuse recharge over the entirely epikarst network. As a useful method, time series analysis is widely used in karst hydrogeology. However, some literatures indicated that it is essential that the results of a time series analysis be interpreted together with the results of other methods used in karst hydrology. In this study, time series analysis method combined with field investigation (including fracture investigation in section and Ground Penetrating Radar (GPR) investigation) have been used to study characteristics of karstic spring hydrograph. Two hillslopes on adjacent mountains located in a small karst basin of Chenqi in the Puding Karst Ecohydrological Observation Station, Guizhou province of China was selected for this study. Ground Penetrating Radar method was used for epikarst thickness investigation. And based on time series analysis method applied to the springs located in study hillsloped, hydrological parameters of epikarst zone with different thickness in two test hillslopes, such as memory effect, response time and the mean delay have been identified. Based on the results of the time series analysis, we can conclude that the study hillslopes the two springs located in respectively have well organized and highly developed epikarst zone. The difference of thickness results in difference of storage and water flow path. Because of the larger storage space, the thicker epikarst zone with stronger adjustability has a laggardly hydrograph pattern. At meantime, more horizontal flow within thicker epikarst zone will via small fracture with low conductivity in lower zone, especially in initial time of precipitation, and which resulting the short regulation time and memory stronger effect.

  14. The Influence of Pretreatment Characteristics and Radiotherapy Parameters on Time Interval to Development of Radiation-Associated Meningioma

    SciTech Connect

    Paulino, Arnold C.; Ahmed, Irfan M.; Mai, Wei Y.; Teh, Bin S.

    2009-12-01

    Purpose: To identify pretreatment characteristics and radiotherapy parameters which may influence time interval to development of radiation-associated meningioma (RAM). Methods and Materials: A Medline/PUBMED search of articles dealing with RAM yielded 66 studies between 1981 and 2006. Factors analyzed included patient age and gender, type of initial tumor treated, radiotherapy (RT) dose and volume, and time interval from RT to development of RAM. Results: A total of 143 patients with a median age at RT of 12 years form the basis of this report. The most common initial tumors or conditions treated with RT were medulloblastoma (n = 27), pituitary adenoma (n = 20), acute lymphoblastic leukemia (n = 20), low-grade astrocytoma (n = 19), and tinea capitis (n = 14). In the 116 patients whose RT fields were known, 55 (47.4%) had a portion of the brain treated, whereas 32 (27.6%) and 29 (25.0%) had craniospinal and whole-brain fields. The median time from RT to develop a RAM or latent time (LT) was 19 years (range, 1-63 years). Male gender (p = 0.001), initial diagnosis of leukemia (p = 0.001), and use of whole brain or craniospinal field (p <= 0.0001) were associated with a shorter LT, whereas patients who received lower doses of RT had a longer LT (p < 0.0001). Conclusions: The latent time to develop a RAM was related to gender, initial tumor type, radiotherapy volume, and radiotherapy dose.

  15. Digestibility, fecal characteristics, and plasma glucose and urea in dogs fed a commercial dog food once or three times daily

    PubMed Central

    Brambillasca, Sebastián; Purtscher, Frederick; Britos, Alejandro; Repetto, José L.; Cajarville, Cecilia

    2010-01-01

    Digestibility, fecal characteristics, and levels of glucose and urea in the plasma were determined in 8 dogs that received 2 different dog foods once or 3 times daily. One dog food (A) was 5 times more expensive than the other (B). Fecal pH and consistency, digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and crude fiber (CF) were determined. Blood samples were taken from 30 min before to 60 min after a meal. Digestibilities of DM, OM, and CP, and fecal consistency were higher, and daily fecal excretion and fecal pH were lower when dogs were fed food A (P < 0.001). The feeding schedule had no effect on plasma glucose and urea. Neither feeding frequency nor food × frequency interactions was significant for the parameters studied. PMID:20440906

  16. Relating low-flow characteristics to the base flow recession time constant at partial record stream gauges

    USGS Publications Warehouse

    Eng, K.; Milly, P.C.D.

    2007-01-01

    Base flow recession information is helpful for regional estimation of low-flow characteristics. However, analyses that exploit such information generally require a continuous record of streamflow at the estimation site to characterize base flow recession. Here we propose a simple method for characterizing base flow recession at low-flow partial record stream gauges (i.e., sites with very few streamflow measurements under low-streamflow conditions), and we use that characterization as the basis for a practical new approach to low-flow regression. In a case study the introduction of a base flow recession time constant, estimated from a single pair of strategically timed streamflow measurements, approximately halves the root-mean-square estimation error relative to that of a conventional drainage area regression. Additional streamflow measurements can be used to reduce the error further.

  17. Investigation on broadband propagation characteristic of terahertz electromagnetic wave in anisotropic magnetized plasma in frequency and time domain

    SciTech Connect

    Tian, Yuan; Han, Yiping; Ai, Xia; Liu, Xiuxiang

    2014-12-15

    In this paper, we investigate the propagation of terahertz (THz) electromagnetic wave in an anisotropic magnetized plasma by JE convolution-finite difference time domain method. The anisotropic characteristic of the plasma, which leads to right-hand circularly polarized (RCP) and right-hand circularly polarized (LCP) waves, has been taken into account. The interaction between electromagnetic waves and magnetized plasma is illustrated by reflection and transmission coefficients for both RCP and LCP THz waves. The effects of both the magnetized plasma thickness and the external magnetized field are analyzed and numerical results demonstrate that the two factors could influence the THz wave greatly. It is worthy to note that besides the reflection and transmission coefficients in the frequency domain, the waveform of the electric field in the time domain varying with thicknesses and external magnetic fields for different polarized direction has been studied.

  18. Statistical characteristic in time-domain of direct current corona-generated audible noise from conductor in corona cage

    NASA Astrophysics Data System (ADS)

    Li, Xuebao; Cui, Xiang; Lu, Tiebing; Ma, Wenzuo; Bian, Xingming; Wang, Donglai; Hiziroglu, Huseyin

    2016-03-01

    The corona-generated audible noise (AN) has become one of decisive factors in the design of high voltage direct current (HVDC) transmission lines. The AN from transmission lines can be attributed to sound pressure pulses which are generated by the multiple corona sources formed on the conductor, i.e., transmission lines. In this paper, a detailed time-domain characteristics of the sound pressure pulses, which are generated by the DC corona discharges formed over the surfaces of a stranded conductors, are investigated systematically in a laboratory settings using a corona cage structure. The amplitude of sound pressure pulse and its time intervals are extracted by observing a direct correlation between corona current pulses and corona-generated sound pressure pulses. Based on the statistical characteristics, a stochastic model is presented for simulating the sound pressure pulses due to DC corona discharges occurring on conductors. The proposed stochastic model is validated by comparing the calculated and measured A-weighted sound pressure level (SPL). The proposed model is then used to analyze the influence of the pulse amplitudes and pulse rate on the SPL. Furthermore, a mathematical relationship is found between the SPL and conductor diameter, electric field, and radial distance.

  19. A characteristic space-time conservation element and solution element method for conservation laws II. Multidimensional extension

    NASA Astrophysics Data System (ADS)

    Shen, Hua; Wen, Chih-Yung

    2016-01-01

    The characteristic space-time conservation element and solution element (CE/SE) schemes proposed by Shen et al. (2015) [15] are straightforward extended to multidimensional schemes on 2D rectangular meshes which strictly follow the space-time conservation law. The schemes for solving both scalar conservation laws and compressible Euler equations with shock waves are developed. They are accurate and robust with CFL widely ranging from 0 to nearly 1. In Euler solvers, the frequently-used Harten, Lax and van Leer (HLL) Riemann solver, contact discontinuity restoring HLLC Riemann solver and Roe Riemann solver are employed to calculate the upwind fluxes as examples. When standard grid-aligned Riemann solvers are employed, the carbuncle phenomena are significantly suppressed when comparing with conventional upwind schemes. If rotated Riemann solvers are employed, nearly carbuncle-free results are obtained. Several well understood numerical examples are carried out to demonstrate that the 2D characteristic CE/SE schemes can simultaneously capture shocks and details of complex flow structures very well.

  20. The JDRF CCTN CGM TIME Trial: Timing of Initiation of continuous glucose Monitoring in Established pediatric type 1 diabetes: study protocol, recruitment and baseline characteristics

    PubMed Central

    2014-01-01

    Background Continuous glucose monitoring (CGM) has been shown to improve glucose control in adults with type 1 diabetes. Effectiveness of CGM is directly linked with CGM adherence, which can be challenging to maintain in children and adolescents. We hypothesize that initiating CGM at the same time as starting insulin pump therapy in pump naïve children and adolescents with type 1 diabetes will result in greater CGM adherence and effectiveness compared to delaying CGM introduction by 6 months, and that this is related to greater readiness for making behaviour change at the time of pump initiation. Methods/Design The CGM TIME Trial is a multicenter randomized controlled trial. Eligible children and adolescents (5-18 years) with established type 1 diabetes were randomized to simultaneous initiation of pump (Medtronic Veo©) and CGM (Enlite©) or to standard pump therapy with delayed CGM introduction. Primary outcomes are CGM adherence and hemoglobin A1C at 6 and 12 months post pump initiation. Secondary outcomes include glycemic variability, stage of readiness, and other patient-reported outcomes with follow-up to 24 months. 144 (95%) of the 152 eligible patients were enrolled and randomized. Allowing for 10% withdrawals, this will provide 93% power to detect a between group difference in CGM adherence and 86% power to detect a between group difference in hemoglobin A1C. Baseline characteristics were similar between the treatment groups. Analysis of 12 month primary outcomes will begin in September 2014. Discussion The CGM TIME Trial is the first study to examine the relationship between timing of CGM initiation, readiness for behaviour change, and subsequent CGM adherence in pump naïve children and adolescents. Its findings will advance our understanding of when and how to initiate CGM in children and adolescents with type 1 diabetes. Trial registration ClinicalTrial.gov NCT01295788. Registered 14 February 2011. PMID:25034216

  1. Timing of seasonal migration in mule deer: effects of climate, plant phenology, and life-history characteristics

    USGS Publications Warehouse

    Monteith, Kevin L.; Bleich, Vernon C.; Stephenson, Thomas R.; Pierce, Beck M.; Conner, Mary M.; Klaver, Robert W.; Bowyer, R. Terry

    2011-01-01

    Phenological events of plants and animals are sensitive to climatic processes. Migration is a life-history event exhibited by most large herbivores living in seasonal environments, and is thought to occur in response to dynamics of forage and weather. Decisions regarding when to migrate, however, may be affected by differences in life-history characteristics of individuals. Long-term and intensive study of a population of mule deer (Odocoileus hemionus) in the Sierra Nevada, California, USA, allowed us to document patterns of migration during 11 years that encompassed a wide array of environmental conditions. We used two new techniques to properly account for interval-censored data and disentangle effects of broad-scale climate, local weather patterns, and plant phenology on seasonal patterns of migration, while incorporating effects of individual life-history characteristics. Timing of autumn migration varied substantially among individual deer, but was associated with the severity of winter weather, and in particular, snow depth and cold temperatures. Migratory responses to winter weather, however, were affected by age, nutritional condition, and summer residency of individual females. Old females and those in good nutritional condition risked encountering severe weather by delaying autumn migration, and were thus risk-prone with respect to the potential loss of foraging opportunities in deep snow compared with young females and those in poor nutritional condition. Females that summered on the west side of the crest of the Sierra Nevada delayed autumn migration relative to east-side females, which supports the influence of the local environment on timing of migration. In contrast, timing of spring migration was unrelated to individual life-history characteristics, was nearly twice as synchronous as autumn migration, differed among years, was related to the southern oscillation index, and was influenced by absolute snow depth and advancing phenology of plants. Plasticity in timing of migration in response to climatic conditions and plant phenology may be an adaptive behavioral strategy, which should reduce the detrimental effects of trophic mismatches between resources and other life-history events of large herbivores. Failure to consider effects of nutrition and other life-history traits may cloud interpretation of phenological patterns of mammals and conceal relationships associated with climate change.

  2. Space-time clustering analysis of wildfires: The influence of dataset characteristics, fire prevention policy decisions, weather and climate.

    PubMed

    Parente, Joana; Pereira, Mário G; Tonini, Marj

    2016-07-15

    The present study focuses on the dependence of the space-time permutation scan statistics (STPSS) (1) on the input database's characteristics and (2) on the use of this methodology to assess changes on the fire regime due to different type of climate and fire management activities. Based on the very strong relationship between weather and the fire incidence in Portugal, the detected clusters will be interpreted in terms of the atmospheric conditions. Apart from being the country most affected by the fires in the European context, Portugal meets all the conditions required to carry out this study, namely: (i) two long and comprehensive official datasets, i.e. the Portuguese Rural Fire Database (PRFD) and the National Mapping Burnt Areas (NMBA), respectively based on ground and satellite measurements; (ii) the two types of climate (Csb in the north and Csa in the south) that characterizes the Mediterranean basin regions most affected by the fires also divide the mainland Portuguese area; and, (iii) the national plan for the defence of forest against fires was approved a decade ago and it is now reasonable to assess its impacts. Results confirmed (1) the influence of the dataset's characteristics on the detected clusters, (2) the existence of two different fire regimes in the country promoted by the different types of climate, (3) the positive impacts of the fire prevention policy decisions and (4) the ability of the STPSS to correctly identify clusters, regarding their number, location, and space-time size in spite of eventual space and/or time splits of the datasets. Finally, the role of the weather on days when clustered fires were active was confirmed for the classes of small, medium and large fires. PMID:27058134

  3. Characteristics of full-time faculty in baccalaureate dental hygiene programs and their perceptions of the academic work environment.

    PubMed

    Collins, Marie A; Zinskie, Cordelia D; Keskula, Douglas R; Thompson, Ana Luz

    2007-11-01

    The purpose of this study was to assess the current characteristics of full-time faculty in baccalaureate dental hygiene programs in the United States. A mail questionnaire was sent to program administrators for distribution to faculty. Program response rate was 89.7 percent (26/29), and full-time faculty response rate was 68.3 percent (114/167). The percentage of dental hygiene faculty who are at the associate or assistant professor ranks was similar at 35.1 percent and 34.2 percent, respectively. Forty percent of faculty are not on a tenure track, and 38.6 percent are tenured. The faculty who responded to this survey were almost exclusively white (93.9 percent) and female (95.6 percent), and their average age was 50.2 years. Faculty reported several areas of dissatisfaction with the academic work environment, including lack of time available for student advisement, class preparation, and keeping current in field, as well as concerns about heavy workload and inadequate compensation. A majority of the respondents (56 percent [39/70]) indicated that they plan to retire from the labor force in ten years or less. Three conclusions may be drawn from the findings of this study: 1) there is a lack of diversity within the dental hygiene faculty, which currently consists primarily of white females with few underrepresented minorities and males; 2) if trends persist, there will be a noticeable shortage of dental hygiene educators in the future as faculty move toward retirement without equivalent numbers of younger individuals joining the ranks of the faculty; and 3) there is a lack of published information regarding dental hygiene faculty characteristics. To address the potential academic workforce shortage, we make two recommendations based indirectly on the findings of this study: 1) the American Dental Association should include more information on dental hygiene faculty characteristics in its existing annual survey of all accredited programs; and 2) the number of advanced education programs in dental hygiene should be increased. PMID:17971568

  4. Biased over- or under-reporting is characteristic of individuals whether over time or by different assessment methods.

    PubMed

    Black, A E; Cole, T J

    2001-01-01

    Seven studies with repeated measurements of energy intake and/or nitrogen intake were examined to determine whether misreporting is characteristic of some persons or occurs randomly. Four of the studies were validated by doubly labeled water measurements of energy expenditure. Reporting validity was expressed as the ratio of energy intake to energy expenditure. Ratios were consistently below the expected value of 1.0 for some subjects and consistently above 1.0 for others, indicating characteristic reporting validity within subjects. Two year-long studies provided 4 to 12 measurements and a total number of days sufficient to measure individual habitual intake. Subjects mean energy intake to basal metabolic rate (BMR) ratios were < 1.35 in 45% and 47% and < 1.35 at every measurement in 25% of subjects. This indicated persistent underreporting over time, because 1.35 x BMR is the minimum energy expenditure compatible with a normally active lifestyle. Three of the studies used more than 1 assessment method (validated by doubly labeled water and/or urinary nitrogen excretion). There was a tendency for persons determined to be underreporters by 1 method to be also underreporters when tested by other methods. We conclude that biased over- or underreporting is characteristic of some persons. Thus, repeat measurements do not necessarily provide valid measures of individual intake, extreme intakes may reflect under- and overreporting rather than true low or high intakes, and subjects most prone to reporting bias may be repeatedly misclassified in quantiles of the distribution. This presents a challenge to dietitians nutritionists, and statisticians both for the design of surveys and the handling of flawed data. PMID:11209588

  5. Bone Marrow Characteristics Associated with Changes in Infarct Size after STEMI: A Biorepository Evaluation from the CCTRN TIME Trial

    PubMed Central

    Schutt, Robert C.; Trachtenberg, Barry H.; Cooke, John P.; Traverse, Jay H.; Henry, Timothy D.; Pepine, Carl J.; Willerson, James T.; Perin, Emerson C.; Ellis, Stephen G.; Zhao, David X. M.; Bhatnagar, Aruni; Johnstone, Brian H.; Lai, Dejian; Resende, Micheline; Ebert, Ray F.; Wu, Joseph C.; Sayre, Shelly L.; Orozco, Aaron; Zierold, Claudia; Simari, Robert D.; Moyé, Lem; Cogle, Christopher R.; Taylor, Doris A.

    2014-01-01

    Rationale Despite significant interest in bone marrow mononuclear cell (BMC) therapy for ischemic heart disease, current techniques have resulted in only modest benefits. However, select patients have shown improvements after autologous BMC therapy, but the contributing factors are unclear. Objective The purpose of this study was to identify BMC characteristics associated with a reduction in infarct size following STEMI. Methods and Results This prospective study comprised patients consecutively enrolled in the CCTRN TIME trial who agreed to have their BMCs stored and analyzed at the CCTRN Biorepository. Change in infarct size between baseline (3 days after percutaneous coronary intervention) and 6-month follow-up was measured by cardiac magnetic resonance imaging (cMRI). Infarct-size measurements and BMC phenotype and function data were obtained for 101 patients (mean age, 56.5 years; mean screening ejection fraction, 37%; mean baseline cMRI ejection fraction, 45%). At 6 months, 75 patients (74.3%) showed a reduction in infarct size (mean change, -21.0%±17.6%). Multiple regression analysis indicated that infarct size reduction was greater in patients who had a larger percentage of CD31+ BMCs (P=0.046) and in those with faster BMC growth rates in CFU-Hill and ECFC functional assays (P=0.033 and P=0.032, respectively). Conclusions This study identified BMC characteristics associated with a better clinical outcome in patients with STEMI and highlighted the importance of endothelial precursor activity in regenerating infarcted myocardium. Furthermore, it suggests that for these STEMI patients, myocardial repair was more dependent on baseline BMC characteristics than on whether the patient underwent intracoronary BMC transplantation. Trial Registration clinicaltrials.gov Identifier: NCT00684021 PMID:25406300

  6. Soft breakdown characteristics of ultralow-k time-dependent dielectric breakdown for advanced complementary metal-oxide semiconductor technologies

    NASA Astrophysics Data System (ADS)

    Chen, Fen; Shinosky, Michael

    2010-09-01

    During technology development, the study of ultralow-k (ULK) time-dependent dielectric breakdown (TDDB) is important for assuring robust reliability. As the technology advances, the increase in ULK leakage current noise level and reversible current change induced by soft breakdown (SBD) during stress has been observed. In this paper, the physical origin of SBD and reversible breakdown, and its correlation to conventional hard breakdowns (HBDs) were extensively studied. Based on constant voltage stress (CVS) and constant current stress (CCS) results, it was concluded that SBD in ULK is an intrinsic characteristic for ULK material, and all first breakdown events most likely are soft instead of hard. Therefore, a unified understanding of SBD and HBD for low-k TDDB was established. Furthermore, the post-SBD and HBD breakdown conduction characteristics were explored and their impacts on circuit operation were discussed. Based on current limited constant voltage stress studies, it was found that the power dissipation, not the stored energy, determined the severity of ULK dielectric breakdown, and the postbreakdown conduction properties. A percolation-threshold controlled, variable-range-hopping (VRH) model was proposed to explain all postbreakdown aspects of SBD and HBD of ULK material.

  7. Experimental determination of tunneling characteristics and dwell times from temperature dependence of Al/Al2O3/Al junctions

    NASA Astrophysics Data System (ADS)

    Patiño, Edgar J.; Kelkar, N. G.

    2015-12-01

    Measurements of current-voltage (I-V) characteristics of a high quality Al/Al2O3/Al junction at temperatures ranging from 3.5 K to 300 K have been used to extract the barrier properties. Fitting results using Simmons's model led to a constant value of barrier width s ˜ 20.8 Å and a continuous increase in the barrier height with decreasing temperature. The latter is used to determine the energy band gap temperature dependence and average phonon frequency ω = 2.05 × 1013 s-1 in Al2O3, which adds confidence to the precision of our measurements. The barrier parameters are used to extract the temperature dependent dwell times in tunneling (τD = 3.6 × 10-16 s at mid-barrier energies) and locate resonances above the barrier.

  8. Studies on Liquefaction Time and Proteins Involved in the Improvement of Seminal Characteristics in Dromedary Camels (Camelus dromedarius).

    PubMed

    Mal, Gorakh; Vyas, Sumant; Srinivasan, Alagiri; Patil, Nitin Vasant Rao; Pathak, Krishan Murari Lal

    2016-01-01

    Semen was collected from six dromedary camels using artificial vagina during rutting season. Liquefaction of the viscous semen occurred in 23.89 ± 1.49 h. During liquefaction, proteins with molecular masses of 24.55 kDa and 22.07 kDa appeared in conjunction with the disappearance of intact 26.00 kDa protein after 18-24 h. These proteins were identified as β-nerve growth factors (β-NGFs) in liquefied camel semen. Guanidine-HCL improves the rheological characteristics of dromedary camel semen along with significant (P < 0.01) increase in sperm motility. No significant differences were found in viability of spermatozoa indicating no visible detrimental effects on spermatozoa. The cause of semen viscosity, as well as proteins that are present in liquefied dromedary camel seminal plasma, is described for the first time. PMID:27022505

  9. Studies on Liquefaction Time and Proteins Involved in the Improvement of Seminal Characteristics in Dromedary Camels (Camelus dromedarius)

    PubMed Central

    Mal, Gorakh; Vyas, Sumant; Srinivasan, Alagiri; Patil, Nitin Vasant Rao; Pathak, Krishan Murari Lal

    2016-01-01

    Semen was collected from six dromedary camels using artificial vagina during rutting season. Liquefaction of the viscous semen occurred in 23.89 ± 1.49 h. During liquefaction, proteins with molecular masses of 24.55 kDa and 22.07 kDa appeared in conjunction with the disappearance of intact 26.00 kDa protein after 18–24 h. These proteins were identified as β-nerve growth factors (β-NGFs) in liquefied camel semen. Guanidine-HCL improves the rheological characteristics of dromedary camel semen along with significant (P < 0.01) increase in sperm motility. No significant differences were found in viability of spermatozoa indicating no visible detrimental effects on spermatozoa. The cause of semen viscosity, as well as proteins that are present in liquefied dromedary camel seminal plasma, is described for the first time. PMID:27022505

  10. Impacts of sludge retention time on sludge characteristics and membrane fouling in a submerged osmotic membrane bioreactor.

    PubMed

    Wang, Xinhua; Chen, Yao; Yuan, Bo; Li, Xiufen; Ren, Yueping

    2014-06-01

    Sludge retention time (SRT) is a feasible method to alleviate the salt accumulation in the osmotic membrane bioreactor (OMBR) by discharging the waste activated sludge. In this study, effects of SRT on sludge characteristics and membrane fouling were investigated using a submerged OMBR under two SRTs of 10 and 15d. The results showed that the lower SRT was helpful for alleviating the salt accumulation and flux decline. Besides that, the removal of NH3-N was significantly influenced by SRT. SRT also had a strong effect on soluble microbial products (SMP) and microbial activity due to the variation of salinity. Microbial diversity analysis indicated that the high salinity environment in the OMBR significantly affected the microbial communities. The flux decline in the OMBR was mainly attributed to the reduced driving force resulting from the salt accumulation, and the reversible fouling was the dominant forward osmosis (FO) membrane fouling in the OMBR. PMID:24727693

  11. Characteristics of the variance effective population size over time using an age structured model with variable size.

    PubMed

    Olsson, Fredrik; Hössjer, Ola; Laikre, Linda; Ryman, Nils

    2013-12-01

    The variance effective population size (NeV) is a key concept in population biology, because it quantifies the microevolutionary process of random genetic drift, and understanding the characteristics of NeV is thus of central importance. Current formulas for NeV for populations with overlapping generations weight age classes according to their reproductive values (i.e. reflecting the contribution of genes from separate age classes to the population growth) to obtain a correct measure of genetic drift when computing the variance of the allele frequency change over time. In this paper, we examine the effect of applying different weights to the age classes using a novel analytical approach for exploring NeV. We consider a haploid organism with overlapping generations and populations of increasing, declining, or constant expected size and stochastic variation with respect to the number of individuals in the separate age classes. We define NeV, as a function of how the age classes are weighted, and of the span between the two points in time, when measuring allele frequency change. With this model, time profiles for NeV can be calculated for populations with various life histories and with fluctuations in life history composition, using different weighting schemes. We examine analytically and by simulations when NeV, using a weighting scheme with respect to reproductive contribution of separate age classes, accurately reflect the variance of the allele frequency change due to genetic drift over time. We show that the discrepancy of NeV, calculated with reproductive values as weights, compared to when individuals are weighted equally, tends to a constant when the time span between the two measurements increases. This constant is zero only for a population with a constant expected population size. Our results confirm that the effect of ignoring overlapping generations, when empirically assessing NeV from allele frequency shifts, gets smaller as the time interval between samples increases. Our model has empirical applications including assessment of (i) time intervals necessary to permit ignoring the effect of overlapping generations for NeV estimation by means of the temporal method, and (ii) effects of life table manipulation on NeV over varying time periods. PMID:24120695

  12. Variations of geometrical and physical characteristics of innermost regions of active galactic nuclei on time-scale of years

    NASA Astrophysics Data System (ADS)

    Bochkarev, Nikolai G.; Shapovalova, Alla I.

    2007-04-01

    Several examples of observational evidences of variations of geometrical and physical characteristics of the innermost regions of Active Galactic Nuclei on the time-scale of years are given. The 15 year long intensive monitoring of NGC 5548 clearly shows significant variations of broad line region (BLR) size on a time scale 6 to 26 days. An analysis of long-term (1984-2003) UBV variations of NGC 4151 shows that the slow changes in the optical continuum are connected with accretion discs (AD) formation and dissipation: during the 1984-1989 deep minimum the former AD is suggested to totally disappear and a new AD to begin to form since 1988-1989, reaching its maximal brightness in 1996. At the same time the fast variations of the continuum are due to flares in AD. For 3C390.3, there is observational evidence of connection between variations in UV and optical continua and radio-jets inner structure. We may figured out, that during the nucleus maximal brightness periods most of the continuum variable radiation is emitted from the jet (˜0.4 pc from the nucleus) and ionizes the surrounding gas, creating a BLR that mainly determines in the broad line emission. During the brightness minima the jet contribution to the ionizing continuum is decreasing and the main broad line emission comes from the "classical" BLR (AD and the surrounding gas). Such a scenario explains two maxima (˜30d and ˜100d) found in the cross-correlation function describing the time-lag of broad line variations relatively to continuum on the base of the results of 3C390.3 optical monitoring in1996-2001.

  13. Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA

    USGS Publications Warehouse

    Pizzuto, James; Schenk, Edward R.; Hupp, Cliff R.; Gellis, Allen; Noe, Greg; Williamson, Elyse; Karwan, Diana L.; O'Neal, Michael; Marquard, Julia; Aalto, Rolf; Newbold, Denis

    2014-01-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loading from particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles are only moved downstream episodically, resting for long periods in storage between transport events. A theory is developed that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage given sediment budget data (by grain size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended sediment transport length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At 5 upland watersheds of the mid-Atlantic region, transport length scales for silt-clay range from 4 to 60 km, while those for sand range from 0.4 to 113 km. Mean sediment velocities for silt-clay range from 0.0072 km/yr to 0.12 km/yr, while those for sand range from 0.0008 km/yr to 0.20 km/yr, 4–6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100–1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to determine the complete distribution of suspended sediment velocities in real watersheds.

  14. Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA

    NASA Astrophysics Data System (ADS)

    Pizzuto, James; Schenk, Edward R.; Hupp, Cliff R.; Gellis, Allen; Noe, Greg; Williamson, Elyse; Karwan, Diana L.; O'Neal, Michael; Marquard, Julia; Aalto, Rolf; Newbold, Denis

    2014-02-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loading from particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles are only moved downstream episodically, resting for long periods in storage between transport events. A theory is developed that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage given sediment budget data (by grain size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended sediment transport length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At 5 upland watersheds of the mid-Atlantic region, transport length scales for silt-clay range from 4 to 60 km, while those for sand range from 0.4 to 113 km. Mean sediment velocities for silt-clay range from 0.0072 km/yr to 0.12 km/yr, while those for sand range from 0.0008 km/yr to 0.20 km/yr, 4-6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100-1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to determine the complete distribution of suspended sediment velocities in real watersheds.

  15. Storage characteristics, nutritive value, and fermentation characteristics of alfalfa packaged in large-round bales and wrapped in stretch film after extended time delays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The production of baled silage is attractive to producers because it offers advantages over dry hay, particularly by limiting risks associated with wet or unstable weather conditions. Our objectives were to test the effects of delayed wrapping on silage fermentation, storage characteristics, and the...

  16. Investigating the spectral characteristics of backscattering from heterogeneous spherical nuclei using broadband finite-difference time-domain simulations

    NASA Astrophysics Data System (ADS)

    Chao, Guo-Shan; Sung, Kung-Bin

    2010-01-01

    Reflectance spectra measured from epithelial tissue have been used to extract size distribution and refractive index of cell nuclei for noninvasive detection of precancerous changes. Despite many in vitro and in vivo experimental results, the underlying mechanism of sizing nuclei based on modeling nuclei as homogeneous spheres and fitting the measured data with Mie theory has not been fully explored. We describe the implementation of a three-dimensional finite-difference time-domain (FDTD) simulation tool using a Gaussian pulse as the light source to investigate the wavelength-dependent characteristics of backscattered light from a nuclear model consisting of a nucleolus and clumps of chromatin embedded in homogeneous nucleoplasm. The results show that small-sized heterogeneities within the nuclei generate about five times higher backscattering than homogeneous spheres. More interestingly, backscattering spectra from heterogeneous spherical nuclei show periodic oscillations similar to those from homogeneous spheres, leading to high accuracy of estimating the nuclear diameter by comparison with Mie theory. In addition to the application in light scattering spectroscopy, the reported FDTD method could be adapted to study the relations between measured spectral data and nuclear structures in other optical imaging and spectroscopic techniques for in vivo diagnosis.

  17. Characteristics of cerebrovascular accidents at time of diagnosis in a series of 98 patients with giant cell arteritis.

    PubMed

    Zenone, Thierry; Puget, Marie

    2013-12-01

    The objective of this study was to determine the characteristics of cerebrovascular accidents at time of diagnosis in patients with giant cell arteritis. Retrospective data were collected from 98 patients at a single hospital with giant cell arteritis (according to the American College of Rheumatology classification criteria) diagnosed between October 1999 and January 2012. Cerebrovascular accident was found at initial presentation in 6 patients (6.1 %, 95 % CIs 2.3-12.9). Most of them had other symptoms of giant cell arteritis when the disease began. Signs reflecting the involvement of vertebro-basilar territory were present in 3 cases. No other case of cerebrovascular accident was described during the follow-up of patient; particularly no case of cerebrovascular accident occurred once corticosteroid therapy for the treatment of giant cell arteritis had been initiated. No differences in the epidemiologic, clinical and laboratory features at the time of diagnosis between patients who had cerebrovascular accidents and the rest of the giant cell arteritis patients were observed. Prognosis was good in our survey. However, there was no case of bilateral vertebral artery occlusion, a condition associated with poor prognosis. The present study confirms that cerebrovascular accidents may be the initial manifestation of giant cell arteritis, an argument in favor of a direct effect of the vasculitis in the development of cerebrovascular accidents rather than a complication of the corticosteroid therapy. The diagnosis of giant cell arteritis should always be considered in an elderly patient with stroke and an unexplained elevation of inflammatory biomarkers. PMID:23873329

  18. Time-Varying Characteristics Analysis and Fuzzy Controller Systematic Design Method for Pressurized Water Reactor Power Control

    SciTech Connect

    Liu Shengzhi; Zhang Naiyao; Cui Zhenhua

    2004-11-15

    In this paper a systematic design method of fuzzy control systems is applied to the pressurized water reactor's (PWR) power control. The paper includes three parts. In the first part, a simplified time-varying linear model of the PWR power system is constructed, and its inner structure and time-varying characteristics are analyzed. That provides a solid basis for study and design of the nuclear reactor power control system. In the second part, a systematic design method of fuzzy control systems is introduced and applied to control the nuclear reactor power process. The design procedures and parameters are given in detail. This systematic design method has some notable advantages. The control of a global fuzzy model can be decomposed into controlling a set of linear submodels. Each submodel controller can be independently designed by using a linear quadratic regulator approach. This systematic design method gives a sufficient and necessary condition to guarantee the stability of fuzzy control systems; thus, better control performance can be obtained due to the accurate control gains. In the third part, the control performance of the nuclear reactor fuzzy control system is examined by simulation experiments, including nuclear reactor power shutdown, start-up, and adjustment operations. The satisfactory experiment results have shown that the systematic design method for fuzzy control systems is effective and feasible.

  19. Characteristics of a fast rise time power supply for a pulsed plasma reactor for chemical vapor destruction

    SciTech Connect

    Lawless, P.A.; Yamamoto, Toshiaki; Shofran, S.P.; Boss, C.B.; Nunez, C.M.; Ramsey, G.H.; Engels, R.L.

    1996-11-01

    Rotating spark gap devices for switching high-voltage direct current (dc) into a corona plasma reactor can achieve pulse rise times in the range of tens of nanoseconds. The fast rise times lead to vigorous plasma generation without sparking at instantaneous applied voltages higher than can be obtained with dc. The resulting energetic plasma is effective for destroying a variety of molecules. The spark gap circuit configuration plays an important role in the effectiveness of the plasma generation. A single-gap circuit is effective for generating moderate peak voltages, but is limited by a multiple sparking phenomenon. A double-gap circuit can achieve equal peak voltages with every spark, but with a reduced number of pulses, compared to the single gap. Both configurations have an upper voltage imposed by the changing impedance of the reactor as voltage and frequency are varied. The pulse characteristics are reported for both types of circuits. The general performance of the reactors for destruction of some compounds with both circuits is also reported.

  20. Who is using snus? - Time trends, socioeconomic and geographic characteristics of snus users in the ageing Swedish population

    PubMed Central

    2011-01-01

    Background The prevalence of smoking in Sweden has decreased in recent decades, and is now among the lowest in the world. During the same period, the use of Swedish moist oral snuff, a smokeless tobacco called snus, has increased. Few studies have evaluated time trends of the socioeconomic and geographic characteristics of snus users in Sweden. This paper contributes to filling that gap. Methods This study utilized the Linnaeus Database, which links national registers with comprehensive individual data on socioeconomic status (SES) to health data from a large ongoing health survey, the Västerbotten Intervention Programme (VIP). The VIP targets the entire middle-aged population of Västerbotten county at ages 40, 50 and 60 years with yearly cross-sectional surveys including self-reported data on tobacco habits. Time trends of snus use among 92,563 VIP-participants across different areas of residence and smoking groups were investigated graphically. Logistic regression was performed to estimate the associations between SES and geographical variables and current use versus non-use of snus. Results Overall, in parallel to decreasing smoking, the increasing trend of snus use in this middle-aged population continues, particularly in 40-year-olds. In both genders, the highest prevalence of snus use was observed among previous smokers. The prevalence of snus use also increased over time among smokers, and was consistently higher compared to those who had never smoked. Among males - both those who had never smoked and previous smokers - low education (OR 1.21, 95%CI 1.06-1.40 and OR 1.28, 95%CI 1.14-1.43), living alone (OR 1.16, 95%CI 1.07-1.27 and OR 1.13, 95%ci 1.04-1.23), low income and living in rural areas was associated with using snus, while this was not seen among male current smokers. Among women, living alone was associated with using snus irrespective of smoking habits. Among female smokers, the OR for snus use increased with higher education. Conclusions A disadvantaged social profile and also higher prevalence in rural areas is observed among male snus users who had never smoked or were previous smokers. Among male smokers there was no association between SES and use of snus. The prevalence of snus use among women is increasing, but is still considerably lower than that of men. The association between snus and SES characteristics is less pronounced among women, although snus is clearly linked to living alone. These patterns should be taken into consideration in tobacco control policies. PMID:22169061

  1. Time-dependent Ginzburg-Landau simulations of the voltage-current characteristic of type-II superconductors with pinning

    NASA Astrophysics Data System (ADS)

    Winiecki, Thomas

    2003-03-01

    In a type-II superconductor, dissipation is associated with the motion of the vortex lattice. This dissipation is reduced by the presence of defects which pin the vortex lattice up to a critical current density. In many applications such as superconducting magnets, one is interested in optimizing the vortex pinning to achieve the maximum critical current. The dynamics of vortices in type-II superconductors may be simulated by directly solving the time-dependent Ginzburg-Landau (TGDL) equations. We propose a new finite-difference algorithm for solving the TDGL equations coupled to appropriate Maxwell equations which is fast enough to allow the study of fully three dimensional problems. As an example, we model current flow in a superconductor subject to a magnetic field. Pinning sites are introduced by adding localized potentials terms to the TDGL equation which deplete the supercurrent density locally. We show that the breakdown of superconductivity is associated with the appearance of channelled vortex flow. We also study the dependence of the critical current on the pinning distribution and find for random distributions a maximum critical current equal to 2% of the depairing current at a pinning density three times larger than the vortex line density, whereas for a regular triangular pinning arrays the critical current is greater than 7% of the depairing current when the pinning density matches the vortex line density. These results suggest that additional pinning mechanisms such as magnetic defects are required to explain the large critical currents observed in some experiments. Further work is needed to include magnetic defects into the TDGL model. Time-dependent Ginzburg-Landau simulations of the voltage-current characteristic of type-II superconductors with pinning, T. Winiecki and C. S. Adams, Phys. Rev. B, 65, 104517 (2002). A fast Semi-Implicit Finite-Difference Method for the TDGL Equations, T. Winiecki and C. S. Adams, J. Comput. Phys. 179, 127-139 (2002).

  2. Studies of ambient noise in shallow water environments off Mexico and Alaska: characteristics, metrics and time-synchronization applications

    NASA Astrophysics Data System (ADS)

    Guerra, Melania

    Sound in the ocean originates from multiple mechanisms, both natural and anthropogenic. Collectively, underwater ambient noise accumulates valuable information about both its sources and the oceanic environment that propagates this noise. Characterizing the features of ambient noise source mechanisms is challenging, but essential, for properly describing an acoustic environment. Disturbances to a local acoustic environment may affect many aquatic species that have adapted to be heavily dependent on this particular sense for survival functions. In the case of marine mammals, which are federally protected, demand exists for understanding such potential impacts, which drives important scientific efforts that utilize passive acoustic monitoring (PAM) tools to inform regulatory decisions. This dissertation presents two independent studies that use PAM data to investigate the characteristics of source mechanisms that dominate ambient noise in two diverse shallow water environments. The study in Chapter 2 directly addresses the concern of how anthropogenic activities can degrade the effectiveness of PAM. In the Alaskan Beaufort Sea, an environment where ambient noise is normally dominated by natural causes, seismic surveys create impulsive sounds to map the composition of the bottom. By inspecting single-sensor PAM data, the spectral characteristics of seismic survey airgun reverberation are measured, and their contribution to the overall ambient noise is quantified. This work is relevant to multiple ongoing mitigation protocols that rely on PAM to acoustically detect marine mammal presence during industrial operations. Meanwhile, Chapter 3 demonstrates that by analyzing data from multiple PAM sensors, features embedded in both directional and omnidirectional ambient noise can be used to develop new time-synchronization processing techniques for aligning autonomous elements of an acoustic array, a tool commonly used in PAM for detecting and tracking marine mammals. Using the time-synchronization procedures shown here, arrays may be built out of stand-alone recorders that simplify the deployment logistics and can be arranged in multiple configurations. Given increasing economic pressures worldwide, anthropogenic activities in the ocean are only expected to expand, and their ambient noise contributions will continue to rise. These studies provide baseline knowledge and practical tools to help properly assess the impact of such source mechanisms in shallow-water acoustic environments.

  3. Dynamic characteristics of a coastal area of lateral spreading using ambient noise time series - Anchor Bay, Malta

    NASA Astrophysics Data System (ADS)

    Galea, Pauline; D'Amico, Sebastiano; Farrugia, Daniela

    2013-04-01

    Anchor Bay and surrounding regions are located on the northwest coast of the island of Malta, Central Mediterranean. The area is characterized by a coastal cliff environment having an outcropping layer of hard coralline limestone (UCL) resting on a thick (up to 50m) layer of clays and marls (Blue Clay, BC). This configuration gives rise to a number of processes leading to coastal instability, in particular lateral spreading phenomena and rock falls. Previous and ongoing studies have identified both lateral spreading rates and vertical motions of up to 27mm per year (Mantovani et al, 2012). The area is an interesting natural laboratory as coastal detachment processes in a number of different stages can be identified and are easily accessible. We investigate the site dynamic characteristics of this study area by recording ambient noise time series (20 minutes long) at over 20 points, over an area of 0.07 km2, using a portable 3-component seismograph (Tromino ) The time series are processed to give both horizontal-to-vertical spectral ratio graphs (HVSR) as well as frequency-dependent polarisation analysis as proposed by Burjanek (2011, 2012). The HVSR graphs illustrate and quantify aspects of site resonance effects due both to underlying geology as well as to mechanical resonance of partly or wholly detached boulders or blocks. The polarization diagrams indicate predominant directions of vibrational effects. Results from this study show an unambiguous distinction between the behavior of "stable" areas, away from the cliff edges, the region of the unstable cliff edge and the actual rockfall areas. Stable regions are characterized by a single and pronounced HVSR resonance peak at around 1.5Hz that are characteristic of all other areas in the Maltese islands having the same underlying geological sequence, while HVSR curves closer to the cliff edge show more complex responses at higher frequencies characteristic of the dynamic behavior of individual detached blocks. Large partly detached blocks (dimensions of several tens of metres) separated from the mainland by deep fractures show the largest HVSR resonance effects with clear peaks in the 3 - 25Hz range and amplitudes up to 6. Polarization effects are visualized through polar-plot representations of frequency histograms, and are also consistent with the geomorphological dynamics of the area. The whole unstable area shows strongly directional polarization, at well-defined frequencies and approximately perpendicular to the cliff edge, but with appreciable differences in frequency and directionality between the individual partly detached blocks. This behavior is indicative of normal-mode vibration. Stable inland areas, on the other hand, show no predominant polarization direction. These results, which will be compared with those from other experiments in the area, have important implications for the understanding of ongoing processes in geologically active and unstable coastal environments.

  4. Biomass characteristics and simultaneous nitrification-denitrification under long sludge retention time in an integrated reactor treating rural domestic sewage.

    PubMed

    Gong, Lingxiao; Jun, Li; Yang, Qing; Wang, Shuying; Ma, Bin; Peng, Yongzhen

    2012-09-01

    In this work, a novel integrated reactor incorporating anoxic fixed bed biofilm reactor (FBBR), oxic moving bed biofilm reactor (MBBR) and settler sequentially was proposed for nitrogen removal from rural domestic sewage. For purposes of achieving high efficiency, low costs and easy maintenance, biomass characteristics and simultaneous nitrification-denitrification (SND) were investigated under long sludge retention time during a 149-day period. The results showed that enhanced SND with proportions of 37.7-42.2% tapped the reactor potentials of efficiency and economy both, despite of C/N ratio of 2.5-4.0 in influent. TN was removed averagely by 69.3% at least, even under internal recycling ratio of 200% and less proportions of biomass assimilation (<3%). Consequently, lower internal recycle and intermittent wasted sludge discharge were feasible to save costs, together with cancellations of sludge return and anoxic stir. Furthermore, biomass with low observed heterotrophic yields (0.053 ± 0.035 g VSS/g COD) and VSS/TSS ratio (<0.55) in MBBR, simplified wasted sludge disposal. PMID:22750493

  5. Arctic underwater noise transients from sea ice deformation: Characteristics, annual time series, and forcing in Beaufort Sea.

    PubMed

    Kinda, G Bazile; Simard, Yvan; Gervaise, Cédric; Mars, Jérôme I; Fortier, Louis

    2015-10-01

    A 13-month time series of Arctic Ocean noise from the marginal ice zone of the Eastern Beaufort Sea is analyzed to detect under-ice acoustic transients isolated from ambient noise with a dedicated algorithm. Noise transients due to ice cracking, fracturing, shearing, and ridging are sorted out into three categories: broadband impulses, frequency modulated (FM) tones, and high-frequency broadband noise. Their temporal and acoustic characteristics over the 8-month ice covered period, from November 2005 to mid-June 2006, are presented and their generation mechanisms are discussed. Correlations analyses showed that the occurrence of these ice transients responded to large-scale ice motion and deformation rates forced by meteorological events, often leading to opening of large-scale leads at main discontinuities in the ice cover. Such a sequence, resulting in the opening of a large lead, hundreds by tens of kilometers in size, along the margin of landfast ice and multiyear ice plume in the Beaufort-Chukchi seas is detailed. These ice transients largely contribute to the soundscape properties of the Arctic Ocean, for both its ambient and total noise components. Some FM tonal transients can be confounded with marine mammal songs, especially when they are repeated, with periods similar to wind generated waves. PMID:26520287

  6. Geostatistical characteristic of space-time variation in quality parameters in Klodzko water supply system (SW part of Poland)

    NASA Astrophysics Data System (ADS)

    Namysłowska-Wilczyńska, Barbara

    2015-04-01

    Selected results of research connected with the development of a (3D) geostatistical hydrogeochemical model of the Klodzko city area, dedicated to the spatial and time variation in the quality parameters in the Klodzko water supply system (SW part of Poland) will be presented. The research covers the period 2007 ÷ 2011. Spatial analyses of the variation in three different quality parameters, i.e. Fe iron [g/m3] content, Mn manganese [g/m3] content and NH4+ ammonium ion [g/m3] content, were carried out. Spatial and time variation in the parameters was analyzed on the basis of the data (2007 ÷ 2011). Thematic databases, containing original data on coordinates X, Y (latitude and longitude) and Z (time - years) and on regionalized variables, i.e. the water quality parameters in the Klodzko water supply system, were created. The input for the studies were the chemical determinations of the quality parameters of water samples taken in the Klodzko water supply system area in different periods of time. These data were subjected to spatial analyses using geostatistical methods. The geostatistical parameters of the assumed theoretical models of directional semivariograms functions of the studied water quality parameters, calculated for the time (years) interval, were used in the ordinary (block) kriging estimation. Generally, the behaviour of the quality parameters in the Klodzko water supply system has been found to vary in space and time. Thanks to the multidirectional spatial analyses some regularities in the variation in the water supply system in the Klodzko city area have been identified. In the considered time interval, the shapes of the directional Fe iron content semivariogram show a tendency to vary periodically. The courses of the directional semivariograms of Mn manganese content and NH4+ ammonium ion content show some tendencies towards directional variation over the passing years: distinctly expressed trends of variability for Mn content and stronger for NH4+ ion content. The kriging estimation results were used to determine the levels of elevated values Z* of the water quality parameters in the years 2007 ÷ 2011 and to forecast these values for the years 2012 ÷ 2014. The maximum values Z* of the quality parameters were stated for the years: 2007, 2008 ÷ 2009 and 2012 (the decreasing trend in Fe iron content averages Z* variation towards the year 2012, the increasing trend in Mn content averages Z* variation towards the year 2012 and the increasing trend in NH4+ ion content averages Z* variation towards the years 2008÷2009 and then the decreasing trend towards the year 2012). Thanks to the (3D) geostatistical model of quality variability parameters, precise characteristics of the studied parameters throughout the Klodzko city water supply system for the years 2007 ÷ 2011 have been obtained.

  7. Demand characteristics, pre-test attitudes and time-on-task trends in the effects of chewing gum on attention and reported mood in healthy volunteers.

    PubMed

    Allen, A P; Smith, A P

    2012-10-01

    Previous research has indicated that chewing gum enhances reported alertness, but has variable effects on attention. Demand characteristics may explain these effects. The current study investigated the effects of gum and demand characteristics on attention and reported mood over time. Participants completed measures of mood and attention, with and without chewing gum. To manipulate demand characteristics, they were told that the hypothesised effect of gum was either positive or negative, or no hypothesis was mentioned. Attitudes towards gum were assessed pre- and post-manipulation. Gum increased reported alertness; this effect was only significant for positive and neutral demand characteristics. Vigilance accuracy was reduced for chewing gum, but only in the fourth minute of the task, and gum reduced focussed attention accuracy, but only for the first 64 trials. Demand characteristics did not moderate time-on-task effects. Gum improved selective attention. A positive effect on response organisation was observed; this was significant when demand characteristics and pre-test attitudes to gum were both negative. The results suggest that demand characteristics moderate effects on self-reported alertness and response organisation, but cannot explain time-on-task effects or variable main effects on other aspects of attention. PMID:22659382

  8. Detection of Characteristic Precipitation Anomaly Patterns of El Nino / La Nina in Time- variable Gravity Fields by GRACE

    NASA Astrophysics Data System (ADS)

    Heki, K.; Morishita, Y.

    2007-12-01

    GRACE (Gravity Recovery and Climate Experiment) satellites, launched in March 2002, have been mapping monthly gravity fields of the Earth, allowing us to infer changes in surface mass, e.g. water and ice. Past findings include the ice mass loss in southern Greenland (Luthcke et al., 2006) and its acceleration in 2004 (Velicogna and Wahr, 2006), crustal dilatation by the 2004 Sumatra Earthquake (Han et al., 2006) and the postseismic movement of water in mantle (Ogawa and Heki, 2007). ENSO (El Nino and Southern Oscillation) brings about global climate impacts, together with its opposite phenomenon, La Nina. Ropelewski and Halpert (1987) showed typical precipitation patterns in ENSO years; characteristic regional-scale precipitation anomalies occur in India, tropical and southern Africa and South America. Nearly opposite precipitation anomalies are shown to occur in La Nina years (Ropelewski and Halpert, 1988). Here we report the detection of such precipitation anomaly patterns in the GRACE monthly gravity data 2002 - 2007, which includes both La Nina (2005 fall - 2006 spring) and El Nino (2006 fall - 2007 spring) periods. We modeled the worldwide gravity time series with constant trends and seasonal changes, and extracted deviations of gravity values at two time epochs, i.e. February 2006 and 2007, and converted them into the changes in equivalent surface water mass. East Africa showed negative gravity deviation (-20.5 cm in water) in 2006 February (La Nina), which reversed to positive (18.7 cm) in 2007 February (El Nino). Northern and southern parts of South America also showed similar see-saw patterns. Such patterns closely resemble to those found meteorologically (Ropelewski and Halpert, 1987; 1988), suggesting the potential of GRACE as a sensor of inter-annual precipitation anomalies through changes in continental water storage. We performed numerical simulations of soil moisture changes at grid points in land area incorporating the CMAP precipitation data, NCEP/NCAR temperature data, and potential evapotranspiration calculated after Thornswaite (1942). We took out the soil moisture anomalies in 2006 February and 2007 February by modeling its time series in the same way as gravity, and confirmed that they are quantitatively consistent with GRACE gravity deviations. Out study demonstrates that satellite gravity data can detect not only of global warming signals in high latitude regions but also inter-annual climate changes in low and middle latitude continental regions.

  9. Time 2 tlk 2nite: Youths’ use of electronic media during family meals and associations with demographic characteristics, family characteristics and foods served

    PubMed Central

    Loth, Katie; Bruening, Meg; Berge, Jerica; Eisenberg, Marla E.; Neumark-Sztainer, Dianne

    2014-01-01

    The study purpose was to examine the frequency of adolescents’ use of electronic media (TV/movie watching, text messaging, talking on the phone, listening to music with headphones and playing with handheld games) at family meals and examine associations with demographic characteristics, rules about media use, family characteristics and the types of foods served at meals using an observational, cross-sectional design. Data were drawn from two coordinated, population-based studies of adolescents (EAT 2010) and their parents (Project F-EAT (Families and Eating Among Teens)). Surveys were completed in 2009–2010. Frequent TV/movie watching during family meals by youth was reported by 25.5% of parents. Multivariate logistic regression analyses indicated significantly higher odds of mealtime media use (p<.05) for girls and older teens. Additionally, higher odds of mealtime media use (p<.05) were also seen among those whose parents had low education levels or were black or Asian; having parental rules about media use significantly reduced these odds. Frequent mealtime media use was significantly associated with lower scores on family communication (p <.05) and scores indicating less importance placed on mealtimes (p<.001). Furthermore, frequent mealtime media use was associated with lower odds of serving green salad, fruit, vegetables, 100% juice and milk at meals whereas higher odds were seen for serving sugar-sweetened beverages (p<.05). The ubiquitous use of mealtime media by adolescents, differences by gender, race/ethnicity, age and parental rules suggest that supporting parents in their efforts to initiate and follow-through on setting mealtime media use rules may be an important public health strategy. PMID:24361006

  10. Time 2 tlk 2nite: use of electronic media by adolescents during family meals and associations with demographic characteristics, family characteristics, and foods served.

    PubMed

    Fulkerson, Jayne A; Loth, Katie; Bruening, Meg; Berge, Jerica; Eisenberg, Marla E; Neumark-Sztainer, Dianne

    2014-07-01

    We examined the frequency of adolescents' use of electronic media (ie, television/movie watching, text messaging, talking on the telephone, listening to music with headphones, and playing with hand-held games) at family meals and examined associations with demographic characteristics, rules about media use, family characteristics, and the types of foods served at meals using an observational, cross-sectional design. Data were drawn from two coordinated, population-based studies of adolescents (Project Eating Among Teens 2010) and their parents (Project Families and Eating Among Teens). Surveys were completed during 2009-2010. Frequent television/movie watching during family meals by youth was reported by 25.5% of parents. Multivariate logistic regression analyses indicated significantly higher odds of mealtime media use (P<0.05) for girls and older teens. In addition, higher odds of mealtime media use (P<0.05) were also seen among those whose parents had low education levels or were black or Asian; having parental rules about media use significantly reduced these odds. Frequent mealtime media use was significantly associated with lower scores on family communication (P<0.05) and scores indicating less importance placed on mealtimes (P<0.001). Furthermore, frequent mealtime media use was associated with lower odds of serving green salad, fruit, vegetables, 100% juice, and milk at meals, whereas higher odds were seen for serving sugar-sweetened beverages (P<0.05). The ubiquitous use of mealtime media by adolescents and differences by sex, race/ethnicity, age, and parental rules suggest that supporting parents in their efforts to initiate and follow-through on setting mealtime media use rules may be an important public health strategy. PMID:24361006

  11. Time

    ERIC Educational Resources Information Center

    Circle, David

    2005-01-01

    When a teacher gives their time to a student, it is more significant to that student than anything else one could do for him or her. Music teachers deal with time all the time. Someone once said that "time is like money: we never have enough." This may seem true; however, time is not like money. One can make more money, but one cannot "make time."…

  12. Force-time curve characteristics and hormonal alterations during an eleven-week training period in elite women weightlifters.

    PubMed

    Haff, G Gregory; Jackson, Janna R; Kawamori, Naoki; Carlock, Jon M; Hartman, Michael J; Kilgore, J Lon; Morris, Robert T; Ramsey, Michael W; Sands, William A; Stone, Michael H

    2008-03-01

    The purpose of this investigation was to study the effects of an 11-week training period performed by female weightlifters. Two weeks before this investigation, baseline measures for total testosterone, cortisol, and testosterone:cortisol ratio were collected. The 11-week training program consisted of the core exercises (i.e., clean, clean and jerk, and snatch) and other supplemental exercises (i.e., clean pull, snatch pull, squat, and front squat). Hormonal, isometric, and dynamic middle thigh pull force-time curve characteristics were assessed biweekly throughout the duration of the investigation, whereas volume load and training intensity were assessed weekly throughout the investigation. The testosterone:cortisol ratio of the baseline (1.19 +/- 0.64) was significantly different from the ratio of weeks 1 (0.67 +/- 0.36) and 9 (0.94 +/- 0.66). When the week-to-week values were compared, week 1 (0.67 +/- 0.36) was significantly different (P < 0.05; eta = 0.84) from week 3 (1.06 +/- 0.54). A very strong correlation (r = -0.83; r = 0.69) was found between the percentage change of the testosterone:cortisol ratio and volume load from weeks 1 to 11. Moderate to very strong correlations were noted between the percentage change in volume load and isometric peak force, peak force during the 30% isometric peak force trial, and peak force during the 100-kg trial during the 11 weeks of training. The primary finding of this study was that alterations in training volume load can result in concomitant changes in the anabolic-to-catabolic balance, as indicated by the testosterone:cortisol ratio, and the ability to generate maximal forces. PMID:18550958

  13. Relationships between functional genes in Lactobacillus delbrueckii ssp. bulgaricus isolates and phenotypic characteristics associated with fermentation time and flavor production in yogurt elucidated using multilocus sequence typing.

    PubMed

    Liu, Wenjun; Yu, Jie; Sun, Zhihong; Song, Yuqin; Wang, Xueni; Wang, Hongmei; Wuren, Tuoya; Zha, Musu; Menghe, Bilige; Heping, Zhang

    2016-01-01

    Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) is well known for its worldwide application in yogurt production. Flavor production and acid producing are considered as the most important characteristics for starter culture screening. To our knowledge this is the first study applying functional gene sequence multilocus sequence typing technology to predict the fermentation and flavor-producing characteristics of yogurt-producing bacteria. In the present study, phenotypic characteristics of 35 L. bulgaricus strains were quantified during the fermentation of milk to yogurt and during its subsequent storage; these included fermentation time, acidification rate, pH, titratable acidity, and flavor characteristics (acetaldehyde concentration). Furthermore, multilocus sequence typing analysis of 7 functional genes associated with fermentation time, acid production, and flavor formation was done to elucidate the phylogeny and genetic evolution of the same L. bulgaricus isolates. The results showed that strains significantly differed in fermentation time, acidification rate, and acetaldehyde production. Combining functional gene sequence analysis with phenotypic characteristics demonstrated that groups of strains established using genotype data were consistent with groups identified based on their phenotypic traits. This study has established an efficient and rapid molecular genotyping method to identify strains with good fermentation traits; this has the potential to replace time-consuming conventional methods based on direct measurement of phenotypic traits. PMID:26547656

  14. Time Variability of Surface-Layer Characteristics over a Mountain Ridge in the Central Himalayas During the Spring Season

    NASA Astrophysics Data System (ADS)

    Solanki, Raman; Singh, Narendra; Kiran Kumar, N. V. P.; Rajeev, K.; Dhaka, S. K.

    2016-03-01

    We present the diurnal variations of surface-layer characteristics during spring (March-May 2013) observed near a mountain ridge at Nainital (29.4°N, 79.5°E, 1926 m above mean sea level), a hill station located in the southern part of the central Himalayas. During spring, this region generally witnesses fair-weather conditions and significant solar heating of the surface, providing favourable conditions for the systematic diurnal evolution of the atmospheric boundary layer. We mainly utilize the three-dimensional wind components and virtual temperature observed with sonic anemometers (sampling at 25 Hz) mounted at 12- and 27-m heights on a meteorological tower. Tilt corrections using the planar-fit method have been applied to convert the measurements to streamline-following coordinate system before estimating turbulence parameters. The airflow at this ridge site is quite different from slope flows. Notwithstanding the prevalence of strong large-scale north-westerly winds, the diurnal variation of the mountain circulation is clearly discernible with the increase of wind speed and a small but distinct change in wind direction during the afternoon period. Such an effect further modulates the surface-layer water vapour content, which increases during the daytime and results in the development of boundary-layer clouds in the evening. The sensible heat flux ( H) shows peak values around noon, with its magnitude increasing from March (222± 46 W m^{-2}) to May (353± 147 W m^{-2}). The diurnal variation of turbulent kinetic energy ( e) is insignificant during March while its mean value is enhanced by 30-50 % of the post-midnight value during the afternoon (1400-1600 IST), delayed by {≈ }2 h compared to the peak in H. This difference between the phase variations of incoming shortwave flux, H and e primarily arise due to the competing effects of turbulent eddies produced by thermals and wind shear, the latter increase significantly with time until nighttime during April-May. Variations of the standard deviations of vertical wind normalized with friction velocity (σ _w/u_{*}) and temperature normalized with scaling temperature (σ _{θ }/T_{*}) as functions of stability parameter ( z / L) indicate that they follow a power-law variation during unstable conditions, with an index of 1/3 for the former and -1/3 for the latter. The coefficients defining the above variations are found in agreement with those derived over flat as well as complex terrain.

  15. Time Variability of Surface-Layer Characteristics over a Mountain Ridge in the Central Himalayas During the Spring Season

    NASA Astrophysics Data System (ADS)

    Solanki, Raman; Singh, Narendra; Kiran Kumar, N. V. P.; Rajeev, K.; Dhaka, S. K.

    2015-10-01

    We present the diurnal variations of surface-layer characteristics during spring (March-May 2013) observed near a mountain ridge at Nainital (29.4N, 79.5E, 1926 m above mean sea level), a hill station located in the southern part of the central Himalayas. During spring, this region generally witnesses fair-weather conditions and significant solar heating of the surface, providing favourable conditions for the systematic diurnal evolution of the atmospheric boundary layer. We mainly utilize the three-dimensional wind components and virtual temperature observed with sonic anemometers (sampling at 25 Hz) mounted at 12- and 27-m heights on a meteorological tower. Tilt corrections using the planar-fit method have been applied to convert the measurements to streamline-following coordinate system before estimating turbulence parameters. The airflow at this ridge site is quite different from slope flows. Notwithstanding the prevalence of strong large-scale north-westerly winds, the diurnal variation of the mountain circulation is clearly discernible with the increase of wind speed and a small but distinct change in wind direction during the afternoon period. Such an effect further modulates the surface-layer water vapour content, which increases during the daytime and results in the development of boundary-layer clouds in the evening. The sensible heat flux (H) shows peak values around noon, with its magnitude increasing from March (222 46 W m^{-2}) to May (353 147 W m^{-2}). The diurnal variation of turbulent kinetic energy (e) is insignificant during March while its mean value is enhanced by 30-50 % of the post-midnight value during the afternoon (1400-1600 IST), delayed by {? }2 h compared to the peak in H. This difference between the phase variations of incoming shortwave flux, H and e primarily arise due to the competing effects of turbulent eddies produced by thermals and wind shear, the latter increase significantly with time until nighttime during April-May. Variations of the standard deviations of vertical wind normalized with friction velocity (? _w/u_{*}) and temperature normalized with scaling temperature (? _{? }/T_{*}) as functions of stability parameter (z / L) indicate that they follow a power-law variation during unstable conditions, with an index of 1/3 for the former and -1/3 for the latter. The coefficients defining the above variations are found in agreement with those derived over flat as well as complex terrain.

  16. Time Series Analysis of Sexual Assault Case Characteristics and the 2007–2008 Period of Post-Election Violence in Kenya

    PubMed Central

    Anastario, Michael P.; Adhiambo Onyango, Monica; Nyanyuki, Joan; Naimer, Karen; Muthoga, Rachel; Sirkin, Susannah; Barrick, Kelle; van Hasselt, Martijn; Aruasa, Wilson; Kibet, Cynthia; Omollo, Grace

    2014-01-01

    Background Following the declaration that President Mwai Kibaki was the winner of the Kenyan presidential election held on December 27, 2007, a period of post-election violence (PEV) took place. In this study, we aimed to identify whether the period of PEV in Kenya was associated with systematic changes in sexual assault case characteristics. Methods and Findings Medical records of 1,615 patients diagnosed with sexual assault between 2007 and 2011 at healthcare facilities in Eldoret (n = 569), Naivasha (n = 534), and Nakuru (n = 512) were retrospectively reviewed to examine characteristics of sexual assault cases over time. Time series and linear regression were used to examine temporal variation in case characteristics relative to the period of post-election violence in Kenya. Key informant interviews with healthcare workers at the sites were employed to triangulate findings. The time series of sexual assault case characteristics at these facilities were examined, with a specific focus on the December 2007–February 2008 period of post-election violence. Prais-Winsten estimates indicated that the three-month period of post-election violence was associated with a 22 percentage-point increase in cases where survivors did not know the perpetrator, a 20 percentage-point increase in cases with more than one perpetrator, and a 4 percentage-point increase in cases that had evidence of abdominal injury. The post-election violence period was also associated with an 18 percentage-point increase in survivors waiting >1 month to report to a healthcare facility. Sensitivity analyses confirmed that these characteristics were specific to the post-election violence time period. Conclusion These results demonstrate systematic patterns in sexual assault characteristics during the PEV period in Kenya. PMID:25170917

  17. The Influence of Student Demographics and Internal Characteristics on GPA, Persistence, and Academic Success of First-Time College Students

    ERIC Educational Resources Information Center

    Rodriguez, David B.

    2013-01-01

    Employing a non-experimental, ex-post facto design, the study examined the relationship of student demographic information and internal characteristics identified from the Learning and Study Strategies Inventory (LASSI) to student persistence, grade point average, and academic success. Cognitive Learning Theory (CLT), which focuses on the internal…

  18. Challenges in Governance: The Leadership Characteristics and Behaviors Valued by Public Library Trustees in Times of Conflict and Contention

    ERIC Educational Resources Information Center

    Arns, Jennifer

    2007-01-01

    Although single-purpose boards and commissions have been used to provide public goods and services since the colonial era, little scholarly attention has been given to the leadership characteristics and behaviors required of their members. As a result, appointing officials and those considering appointment have had little systematic guidance

  19. Influencing Work-Related Learning: The Role of Job Characteristics and Self-Directed Learning Orientation in Part-Time Vocational Education

    ERIC Educational Resources Information Center

    Gijbels, David; Raemdonck, Isabel; Vervecken, Dries

    2010-01-01

    Based on the Demand-Control-Support (DCS) model, the present paper aims to investigate the influence of job characteristics such as job demands, job control, social support at work and self-directed learning orientation on the work-related learning behaviour of workers. The present study was conducted in a centre for part-time vocational education

  20. It Takes Two to Tango, Doesn't It? The Influence of Couple Characteristics on the Timing of the Birth of the First Child.

    ERIC Educational Resources Information Center

    Corijn, Martine

    1996-01-01

    The timing of the first childbirth is studied using information about characteristics of both partners. The context specificity of the determinants of childbearing is examined by comparing couples with and without cohabitation experience. The sociocultural specificity is studied using data from the Netherlands and Flanders. Discusses findings. (KW)

  1. Three list scheduling temporal partitioning algorithm of time space characteristic analysis and compare for dynamic reconfigurable computing

    NASA Astrophysics Data System (ADS)

    Chen, Naijin

    2013-03-01

    Level Based Partitioning (LBP) algorithm, Cluster Based Partitioning (CBP) algorithm and Enhance Static List (ESL) temporal partitioning algorithm based on adjacent matrix and adjacent table are designed and implemented in this paper. Also partitioning time and memory occupation based on three algorithms are compared. Experiment results show LBP partitioning algorithm possesses the least partitioning time and better parallel character, as far as memory occupation and partitioning time are concerned, algorithms based on adjacent table have less partitioning time and less space memory occupation.

  2. Time?

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.

    2013-09-01

    The concept of time in the `clockwork' Newtonian world was irrelevant; and has generally been ignored until recently by several generations of physicists since the implementation of quantum mechanics. We will set aside the utility of time as a property relating to physical calculations of events relating to a metrics line element or as an aspect of the transformation of a particles motion/interaction in a coordinate system or in relation to thermodynamics etc., i.e. we will discard all the usual uses of time as a concept used to circularly define physical parameters in terms of other physical parameters; concentrating instead on time as an aspect of the fundamental cosmic topology of our virtual reality especially as it inseparably relates to the nature and role of the observer in natural science.

  3. Visualization of the laminar-turbulent transition in the flow over an airfoil using the smoke-wire technique

    NASA Technical Reports Server (NTRS)

    Batill, S. M.; Mueller, T. J.

    1980-01-01

    A flow visualization technique, referred to as the smoke-wire, was used for visualization of the transition of the free shear layer associated with the laminar separation bubble of a NACA 66 sub 3-018 airfoil section at low Reynolds number (50,000-130,000). The smoke-wire technique allows the introduction of fine smoke streaklines into the flow field through the electrical resistive heating of a very fine wire which has been coated with oil and which is located upstream from the leading edge of the airfoil section. Streakline data were collected using both high speed still and motion picture photography.

  4. Do Diligent Students Perform Better? Complex Relations between Student and Course Characteristics, Study Time, and Academic Performance in Higher Education

    ERIC Educational Resources Information Center

    Masui, Chris; Broeckmans, Jan; Doumen, Sarah; Groenen, Anne; Molenberghs, Geert

    2014-01-01

    Research has reported equivocal results regarding the relationship between study time investment and academic performance in higher education. In the setting of the active, assignment-based teaching approach at Hasselt University (Belgium), the present study aimed (a) to further clarify the role of study time in academic performance, while taking

  5. CHARACTERISTICS OF A FAST RISE TIME POWER SUPPLY FOR A PULSED PLASMA REACTOR FOR CHEMICAL VAPOR DESTRUCTION

    EPA Science Inventory

    Rotating spark gap devices for switching high-voltage direct current (dc) into a corona plasma reactor can achieve pulse rise times in the range of tens of nanoseconds. The fast rise times lead to vigorous plasma generation without sparking at instantaneous applied voltages highe...

  6. Do Diligent Students Perform Better? Complex Relations between Student and Course Characteristics, Study Time, and Academic Performance in Higher Education

    ERIC Educational Resources Information Center

    Masui, Chris; Broeckmans, Jan; Doumen, Sarah; Groenen, Anne; Molenberghs, Geert

    2014-01-01

    Research has reported equivocal results regarding the relationship between study time investment and academic performance in higher education. In the setting of the active, assignment-based teaching approach at Hasselt University (Belgium), the present study aimed (a) to further clarify the role of study time in academic performance, while taking…

  7. Effects of time after a second dose of immunization against GnRF (Improvest) independent of age at slaughter on commercial bacon slicing characteristics of immunologically castrated barrows.

    PubMed

    Tavárez, M A; Bohrer, B M; Herrick, R T; Mellencamp, M A; Matulis, R J; Ellis, M; Boler, D D; Dilger, A C

    2016-01-01

    The objective was to determine the effects of time after a second dose of anti-GnRF immunization on fresh belly characteristics and slicing yields of immunologically castrated (IC) barrows, physically castrated (PC) barrows and gilts slaughtered at 24 weeks of age. The second dose was staggered so that IC barrows were slaughtered at 4, 6, 8, or 10 weeks after the second dose. Fresh belly characteristics (N=141) were collected at slaughter and bacon was manufactured commercially. The main effects in the model were treatment and the random effects of block and block within replication. Thickness, flop distance, and lipid content increased (L; P<0.04) and iodine value tended to decrease (L; P=0.08) with time after the second dose in IC barrows. Slicing yields increased with time after the second dose (L; P<0.01), but were similar (P=0.11) among sexes. Increasing time of slaughter after second anti-GnRF dose improves fresh belly and bacon slicing characteristics in IC barrows. PMID:26401629

  8. Real-time demonstration of the main characteristics of chaos in the motion of a real double pendulum

    NASA Astrophysics Data System (ADS)

    Vadai, Gergely; Gingl, Zoltán; Mellár, János

    2012-07-01

    Several studies came to the conclusion that chaotic phenomena are worth including in high school and undergraduate education. The double pendulum is one of the simplest systems that is chaotic; therefore, numerical simulations and theoretical studies of it have been given large publicity, and thanks to its spectacular motion, it has become one of the most famous demonstration tools of chaos, either through simulations or in real experiments. Although several attempts have been made to use the experiment in laboratory exercises, as the friction in the real experiment changes the nature of the motion and the values of characteristic parameters during the motion, examining the measured (dissipative) motion and comparing it with theoretical results raises several questions. In our review, we present a measurement system which is able to analyse these questions. The system, which consists of simple yet precise data acquisition electronics, easily attainable sensors, a Bluetooth module (to communicate with the PC) and open-source software, demonstrates on-line the main characteristics of chaos and the methods of its study and allows us to analyse the dissipative motion. Further information (including downloadable software) is provided on a dedicated page, http://www.inf.u-szeged.hu/noise/Research/DoublePendulum/.

  9. Turbulence characteristics of the noise producing region of an excited round jet. I - Time-average flow properties

    NASA Astrophysics Data System (ADS)

    Baltas, C.; Morris, P. J.

    1984-10-01

    Experiments were conducted to determine the mean turbulence characteristics of the noise-producing region of a 3 in. cold excited round jet. The jet was excited by plane acoustic waves with a high amplitude of excitation (2 percent of the jet dynamic head), and at a Strouhal number of 0.5. The flow Reynolds number was 280,000. The exit boundary layer was made turbulent by artificially tripping it with sandpaper strips. The data were obtained with single and X-hot-wires and processed in digital form. Mean and higher order statistics were also deduced. The results showed an increase in all three velocity components and stresses. However, most of the increase was noticed from the longitudinal component, while the changes in the radial velocity and the azimuthal component were much smaller. Substantial widening of the jet occurred, accompanied by a shortening of the potential core. Increased rates of production of energy close to the lip-line were a characteristic feature of the mixing region behavior.

  10. Turbulence characteristics of the noise producing region of an excited round jet. I - Time-average flow properties

    NASA Technical Reports Server (NTRS)

    Baltas, C.; Morris, P. J.

    1984-01-01

    Experiments were conducted to determine the mean turbulence characteristics of the noise-producing region of a 3 in. cold excited round jet. The jet was excited by plane acoustic waves with a high amplitude of excitation (2 percent of the jet dynamic head), and at a Strouhal number of 0.5. The flow Reynolds number was 280,000. The exit boundary layer was made turbulent by artificially tripping it with sandpaper strips. The data were obtained with single and X-hot-wires and processed in digital form. Mean and higher order statistics were also deduced. The results showed an increase in all three velocity components and stresses. However, most of the increase was noticed from the longitudinal component, while the changes in the radial velocity and the azimuthal component were much smaller. Substantial widening of the jet occurred, accompanied by a shortening of the potential core. Increased rates of production of energy close to the lip-line were a characteristic feature of the mixing region behavior.

  11. Engaging nursing home residents with dementia in activities: The effects of modeling, presentation order, time of day, and setting characteristics

    PubMed Central

    Cohen-Mansfield, Jiska; Thein, Khin; Dakheel-Ali, Maha; Marx, Marcia S.

    2011-01-01

    We examined the impact of setting characteristics and presentation effects on engagement with stimuli in a group of 193 nursing home residents with dementia (recruited from a total of seven nursing homes). Engagement was assessed through systematic observations using the Observational Measurement of Engagement (OME), and data pertaining to setting characteristics (background noise, light, and number of persons in proximity) were recorded via the environmental portion of the Agitation Behavior Mapping Inventory (ABMI; Cohen-Mansfield, Werner, & Marx, (1989). An observational study of agitation in agitated nursing home residents. International Psychogeriatrics, 1, 153–165). Results revealed that study participants were engaged more often with moderate levels of sound and in the presence of a small group of people (from four to nine people). As to the presentation effects, multiple presentations of the same stimulus were found to be appropriate for the severely impaired as well as the moderately cognitively impaired. Moreover, modeling of the appropriate behavior significantly increased engagement, with the severely cognitively impaired residents receiving the greatest benefit from modeling. These findings have direct implications for the way in which caregivers could structure the environment in the nursing home and how they could present stimuli to residents in order to optimize engagement in persons with dementia. PMID:20455123

  12. Relationship of mechanical characteristics and microstructural features to the time-dependent edge notch sensitivity of inconel 718 sheet

    NASA Technical Reports Server (NTRS)

    Wilson, D. J.

    1971-01-01

    Time-dependent notch sensitivity of Inconel 718 sheet was observed at 900 F to 1200 F (482 - 649 C). It occurred when edge-notched specimens were loaded below the yield strength and smooth specimen tests showed that small amounts of creep consumed large rupture life fractions. The severity of the notch sensitivity was reduced by decreasing the solution temperature, increasing the time and/or temperature of aging and increasing the test temperature to 1400 F (760 C). Elimination of time-dependent notch sensitivity correlated with a change in dislocation motion mechanism from shearing to by-passing precipitate particles.

  13. Langmuir probe measurements in a time-fluctuating-highly ionized non-equilibrium cutting arc: Analysis of the electron retarding part of the time-averaged current-voltage characteristic of the probe

    SciTech Connect

    Prevosto, L.; Mancinelli, B.; Kelly, H.; Instituto de Física del Plasma , Departamento de Física, Facultad de Ciencias Exactas y Naturales Ciudad Universitaria Pab. I, 1428 Buenos Aires

    2013-12-15

    This work describes the application of Langmuir probe diagnostics to the measurement of the electron temperature in a time-fluctuating-highly ionized, non-equilibrium cutting arc. The electron retarding part of the time-averaged current-voltage characteristic of the probe was analysed, assuming that the standard exponential expression describing the electron current to the probe in collision-free plasmas can be applied under the investigated conditions. A procedure is described which allows the determination of the errors introduced in time-averaged probe data due to small-amplitude plasma fluctuations. It was found that the experimental points can be gathered into two well defined groups allowing defining two quite different averaged electron temperature values. In the low-current region the averaged characteristic was not significantly disturbed by the fluctuations and can reliably be used to obtain the actual value of the averaged electron temperature. In particular, an averaged electron temperature of 0.98 ± 0.07 eV (= 11400 ± 800 K) was found for the central core of the arc (30 A) at 3.5 mm downstream from the nozzle exit. This average included not only a time-average over the time fluctuations but also a spatial-average along the probe collecting length. The fitting of the high-current region of the characteristic using such electron temperature value together with the corrections given by the fluctuation analysis showed a relevant departure of local thermal equilibrium in the arc core.

  14. Mapping forest height, foliage height profiles and disturbance characteristics with time series of gap-filled Landsat and ALI imagery

    NASA Astrophysics Data System (ADS)

    Helmer, E.; Ruzycki, T. S.; Wunderle, J. M.; Kwit, C.; Ewert, D. N.; Voggesser, S. M.; Brandeis, T. J.

    2011-12-01

    We mapped tropical dry forest height (RMSE = 0.9 m, R2 = 0.84, range 0.6-7 m) and foliage height profiles with a time series of gap-filled Landsat and Advanced Land Imager (ALI) imagery for the island of Eleuthera, The Bahamas. We also mapped disturbance type and age with decision tree classification of the image time series. Having mapped these variables in the context of studies of wintering habitat of an endangered Nearctic-Neotropical migrant bird, the Kirtland's Warbler (Dendroica kirtlandii), we then illustrated relationships between forest vertical structure, disturbance type and counts of forage species important to the Kirtland's Warbler. The ALI imagery and the Landsat time series were both critical to the result for forest height, which the strong relationship of forest height with disturbance type and age facilitated. Also unique to this study was that seven of the eight image time steps were cloud-gap-filled images: mosaics of the clear parts of several cloudy scenes, in which cloud gaps in a reference scene for each time step are filled with image data from alternate scenes. We created each cloud-cleared image, including a virtually seamless ALI image mosaic, with regression tree normalization of the image data that filled cloud gaps. We also illustrated how viewing time series imagery as red-green-blue composites of tasseled cap wetness (RGB wetness composites) aids reference data collection for classifying tropical forest disturbance type and age.

  15. The effect of varying Co layer thickness on the time-temperature characteristics of Co/Sb semimetal embedded magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Madden, M. R.; Alshammary, T.; Grove, B.; Phillips, J.; Reaz, K.; Hensley, S.; Kenning, G. G.

    2015-03-01

    We report the effect of varying cobalt thickness on the temperature-dependent time decay of the electrical resistance of Co/Sb multilayer samples. We find that for a given temperature, a five fold change in the Co thickness produces a 100 fold change in the characteristic decay time of the resistance. We find that the characteristic decay time, as a function of temperature, follows an Arrhenius law. During deposition, the Co evolves single domain magnetic nanoparticles, on the Sb, in either a Volmer-Weber or Stranski-Krastanov growth mode. This metastable state is then encased in 2.5 nm of Sb producing an embedded nanoparticle system. Scanning tunneling microscopy measurements taken before sample aging (annealing at a given temperature for enough time to complete the resistance decay) and after aging show that these nanoparticles undergo morphological transformations during aging. These transformations lead to well defined time dependent decays in both the magnetization and the electrical resistance, making this material an excellent candidate for an electronic time-temperature sensor.

  16. The effect of varying Co layer thickness on the time-temperature characteristics of Co/Sb semimetal embedded magnetic nanoparticles

    SciTech Connect

    Madden, M. R.; Alshammary, T.; Grove, B.; Phillips, J.; Reaz, K.; Hensley, S.; Kenning, G. G.

    2015-03-14

    We report the effect of varying cobalt thickness on the temperature-dependent time decay of the electrical resistance of Co/Sb multilayer samples. We find that for a given temperature, a five fold change in the Co thickness produces a 100 fold change in the characteristic decay time of the resistance. We find that the characteristic decay time, as a function of temperature, follows an Arrhenius law. During deposition, the Co evolves single domain magnetic nanoparticles, on the Sb, in either a Volmer-Weber or Stranski-Krastanov growth mode. This metastable state is then encased in 2.5 nm of Sb producing an embedded nanoparticle system. Scanning tunneling microscopy measurements taken before sample aging (annealing at a given temperature for enough time to complete the resistance decay) and after aging show that these nanoparticles undergo morphological transformations during aging. These transformations lead to well defined time dependent decays in both the magnetization and the electrical resistance, making this material an excellent candidate for an electronic time-temperature sensor.

  17. Development of the Glenn-Heat-Transfer (Glenn-HT) Computer Code to Enable Time-Filtered Navier Stokes (TFNS) Simulations and Application to Film Cooling on a Flat Plate Through Long Cooling Tubes

    NASA Technical Reports Server (NTRS)

    Ameri, Ali A.; Shyam, Vikram; Rigby, David; Poinsatte, Phillip; Thurman, Douglas; Steinthorsson, Erlendur

    2014-01-01

    Computational fluid dynamics (CFD) analysis using Reynolds-averaged Navier-Stokes (RANS) formulation for turbomachinery-related flows has enabled improved engine component designs. RANS methodology has limitations that are related to its inability to accurately describe the spectrum of flow phenomena encountered in engines. Examples of flows that are difficult to compute accurately with RANS include phenomena such as laminar/turbulent transition, turbulent mixing due to mixing of streams, and separated flows. Large eddy simulation (LES) can improve accuracy but at a considerably higher cost. In recent years, hybrid schemes that take advantage of both unsteady RANS and LES have been proposed. This study investigated an alternative scheme, the time-filtered Navier-Stokes (TFNS) method applied to compressible flows. The method developed by Shih and Liu was implemented in the Glenn-Heat-Transfer (Glenn-HT) code and applied to film-cooling flows. In this report the method and its implementation is briefly described. The film effectiveness results obtained for film cooling from a row of 30deg holes with a pitch of 3.0 diameters emitting air at a nominal density ratio of unity and two blowing ratios of 0.5 and 1.0 are shown. Flow features under those conditions are also described.

  18. Development of the Glenn Heat-Transfer (Glenn-HT) Computer Code to Enable Time-Filtered Navier-Stokes (TFNS) Simulations and Application to Film Cooling on a Flat Plate Through Long Cooling Tubes

    NASA Technical Reports Server (NTRS)

    Ameri, Ali; Shyam, Vikram; Rigby, David; Poinsatte, Phillip; Thurman, Douglas; Steinthorsson, Erlendur

    2014-01-01

    Computational fluid dynamics (CFD) analysis using Reynolds-averaged Navier-Stokes (RANS) formulation for turbomachinery-related flows has enabled improved engine component designs. RANS methodology has limitations that are related to its inability to accurately describe the spectrum of flow phenomena encountered in engines. Examples of flows that are difficult to compute accurately with RANS include phenomena such as laminar/turbulent transition, turbulent mixing due to mixing of streams, and separated flows. Large eddy simulation (LES) can improve accuracy but at a considerably higher cost. In recent years, hybrid schemes that take advantage of both unsteady RANS and LES have been proposed. This study investigated an alternative scheme, the time-filtered Navier-Stokes (TFNS) method applied to compressible flows. The method developed by Shih and Liu was implemented in the Glenn-Heat-Transfer (Glenn-HT) code and applied to film-cooling flows. In this report the method and its implementation is briefly described. The film effectiveness results obtained for film cooling from a row of 30deg holes with a pitch of 3.0 diameters emitting air at a nominal density ratio of unity and two blowing ratios of 0.5 and 1.0 are shown. Flow features under those conditions are also described.

  19. Effects of polychlorinated biphenyls and nutritional restriction on barbituate-induced sleeping times and selected blood characteristics in raccoons (Procyon lotor)

    SciTech Connect

    Montz, W.E.; Card, W.C.; Kirkpatrick, R.L.

    1982-05-01

    Hepatic microsomal enzyme activity was induced in wild-trapped raccoons (Procyon lotor) and selected blood characteristics were measured in an effort to detect responses due to PCB ingestion, nutritional restriction, and their interactions. Barbiturate-induced sleeping times were used as an index of hepatic microsomal activity because they have been used reliably by other workers. Blood characteristics examined in the study were nonesterified fatty acids (NEFA), cholesterol, and three ketone bodies (D-(-)-3-hydroxybutyrate, acetoacetate, and acetone). Results show a reduction in sleeping times, elevated NEFA and D-(-)-3-hydroxybutyrate concentrations, and lower cholesterol concentrations in PCB-treated groups. A highly significant interaction between PCB treatment and nutritional restriction was observed in acetoacetate concentrations. (JMT)

  20. Time-Series Analyses of Supergranule Characteristics Compared Between SDO/HMI, SOHO/MDI and Simulated Datasets

    NASA Astrophysics Data System (ADS)

    Williams, P. E.; Pesnell, W. D.

    2011-12-01

    Supergranulation is a well-observed solar phenomenon despite its underlying mechanisms remaining a mystery. Originally considered to arise due to convective motions, alternative mechanisms have been suggested such as the cumulative downdrafts of granules as well as displaying wave-like properties. Supergranule characteristics are well documented, however. Supergranule cells are approximately 35 Mm across, have lifetimes on the order of a day and have divergent horizontal velocities of around 300 m/s, a factor of 10 higher than their central radial components. While they have been observed using Doppler methods for more than half a century, their existence is also observed in other datasets such as magnetograms and Ca II K images. These datasets clearly show the influence of supergranulation on solar magnetism and how the local field is organized by the flows of supergranule cells. The Heliospheric and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO) continues to produce Doppler images enabling the continuation of supergranulation studies made with SOHO/MDI, but with superior temporal and spatial resolution. The size-distribution of divergent cellular flows observed on the photosphere now reaches down to granular scales, allowing contemporaneous comparisons between the two flow components. SOHO/MDI Doppler observations made during the minima of cycles 22/23 and 23/24 exhibit fluctuations of supergranule characteristics (global averages of the supergranule size, size-range and horizontal velocity) with periods of 3-5 days. Similar fluctuations have been observed in SDO/HMI Dopplergrams and the high correlation between co-temporal HMI & MDI suggest a solar origin. Their nature has been probed by invoking data simulations that produce realistic Dopplergrams based on MDI data.

  1. Time-Series Analyses of Supergranule Characteristics Compared Between SDO/HMI, SOHO/MDI and Simulated Datasets

    NASA Technical Reports Server (NTRS)

    Williams, Peter E.; Pesnell, William Dean

    2012-01-01

    Supergranulation is a well-observed solar phenomenon despite its underlying mechanisms remaining a mystery. Originally considered to arise due to convective motions, alternative mechanisms have been suggested such as the cumulative downdrafts of granules as well as displaying wave-like properties. Supergranule characteristics are well documented, however. Supergranule cells are approximately 35 Mm across, have lifetimes on the order of a day and have divergent horizontal velocities of around 300 mis, a factor of 10 higher than their central radial components. While they have been observed using Doppler methods for more than half a century, their existence is also observed in other datasets such as magneto grams and Ca II K images. These datasets clearly show the influence of supergranulation on solar magnetism and how the local field is organized by the flows of supergranule cells. The Heliospheric and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO) continues to produce Doppler images enabling the continuation of supergranulation studies made with SOHO/MDI, but with superior temporal and spatial resolution. The size-distribution of divergent cellular flows observed on the photosphere now reaches down to granular scales, allowing contemporaneous comparisons between the two flow components. SOHO/MDI Doppler observations made during the minima of cycles 22/23 and 23/24 exhibit fluctuations of supergranule characteristics (global averages of the supergranule size, size-range and horizontal velocity) with periods of 3-5 days. Similar fluctuations have been observed in SDO/HMI Dopplergrams and the high correlation between co-temporal HMI & MOl suggest a solar origin. Their nature has been probed by invoking data simulations that produce realistic Dopplergrams based on MOl data.

  2. Investigation of Thermal Conductivity and Heat Characteristics of Oil Sands Using Ultrasound Irradiation for Shortening the Preheating Time

    NASA Astrophysics Data System (ADS)

    Kamagata, Shingo; Kawamura, Youhei; Okawa, Hirokazu; Mizutani, Koichi

    2012-07-01

    Oil sands are attractive as an energy resource. Bitumen, which is found in oil sands, has high viscosity, so that it does not flow. Most oil sands are underground and are developed with a method called steam-assisted gravity drainage (SAGD). Hot steam is injected underground to fluidize bitumen and promote its recovery. However, the preheating time is too long. One way of reducing running costs is by shortening the preheating time. Previous studies have found that bitumen can be extracted from oil sands efficiently by applying ultrasonic irradiation, but SAGD was not applied directly in these cases. Thus, the purpose of this study is to apply ultrasonic irradiation to SAGD, thereby shortening the preheating time of oil sands. As a model experiment for SAGD, heat transfer experiments in a sand layer made with Toyoura sand and silicone oil were conducted and the thermal effect with ultrasound was investigated.

  3. Relationships between force-time characteristics of the isometric midthigh pull and dynamic performance in professional rugby league players.

    PubMed

    West, Daniel J; Owen, Nick J; Jones, Marc R; Bracken, Richard M; Cook, Christian J; Cunningham, Dan J; Shearer, David A; Finn, Charlotte V; Newton, Robert U; Crewther, Blair T; Kilduff, Liam P

    2011-11-01

    There is considerable conflict within the literature regarding the relevance of isometric testing for the assessment of neuromuscular function within dynamic sports. The aim of this study was to determine the relationship between isometric measures of force development and dynamic performance. Thirty-nine professional rugby league players participated in this study. Forty-eight hours after trial familiarization, participants performed a maximal isometric midthigh pull, with ∼120-130° bend at the knee, countermovement jump (CMJ), and a 10-m sprint. Force-time data were processed for peak force (PF), force at 100 milliseconds (F100ms), and peak rate of force development (PRFD). Analysis was carried out using Pearson's product moment correlation with significance set at p < 0.05. The PF was not related to dynamic performance; however, when expressed relative to body weight, it was significantly correlated with both 10-m time and CMJ height (r = -0.37 and 0.45, respectively, p < 0.05). The F100ms was inversely related to 10-m time (r = -0.54, p < 0.01); moreover, when expressed relative to body weight, it was significantly related to both 10-m time and CMJ height (r = -0.68 and 0.43, p < 0.01). In addition, significant correlations were found between PRFD and 10-m time (r = -0.66, p < 0.01) and CMJ height (r = 0.387, p < 0.01). In conclusion, this study provides evidence that measures of maximal strength and explosiveness from isometric force-time curves are related to jump and sprint acceleration performance in professional rugby league players. PMID:21993026

  4. Compliance to a Cell Phone-Based Ecological Momentary Assessment Study: The Effect of Time and Personality Characteristics

    ERIC Educational Resources Information Center

    Courvoisier, Delphine S.; Eid, Michael; Lischetzke, Tanja

    2012-01-01

    Ecological momentary assessment (EMA) is a method that is now widely used to study behavior and mood in the settings in which they naturally occur. It maximizes ecological validity and avoids the limitations of retrospective self-reports. Compliance patterns across time have not been studied. Consistent compliance patterns could lead to data not…

  5. Concentration- and time-response characteristics of plaque isolates of Agrotis ipsilon multiple nucleopolyhedrovirus derived from a field isolate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plaque isolates derived from the Illinois field isolate of Agrotis ipsilon multiple nucleopolyhedrovirus are distinguished by the presence or absence of a small deletion in the baculovirus egt (ecdysteroid UDP-glucosyltransferase) coding sequence. Dose-response and time-response bioassays were perf...

  6. Performance characteristics of the new Abbott Real Time MTB assay for detection of Mycobacterium tuberculosis complex in respiratory specimens.

    PubMed

    Vinuesa, Víctor; Navarro, David; Poujois, Sandrine; Zaragoza, Susana; Borrás, Rafael

    2016-03-01

    The performance of the Abbott Real Time MTB assay for detection of Mycobacterium tuberculosis complex in respiratory specimens was evaluated using a standard culture as the reference. The overall concordance between both methods was 0.95. The assay displayed an excellent sensitivity (100% for smear-positive/92.3% for smear-negative specimens) and specificity (100%). PMID:26658312

  7. Real-time simulation of jet engines with digital computer. 1: Fabrication and characteristics of the simulator

    NASA Technical Reports Server (NTRS)

    Nishio, K.; Sugiyama, N.; Koshinuma, T.; Hashimoto, T.; Ohata, T.; Ichikawa, H.

    1983-01-01

    The fabrication and performance of a real time jet engine simulator using a digital computer are discussed. The use of the simulator in developing the components and control system of a jet engine is described. Comparison of data from jet engine simulation tests with actual engine tests was conducted with good agreement.

  8. The Effect of Loans on Time to Doctorate Degree: Differences by Race/Ethnicity, Field of Study, and Institutional Characteristics

    ERIC Educational Resources Information Center

    Kim, Dongbin; Otts, Cindy

    2010-01-01

    Much of the focus of research on the impact of financial aid (debt in particular) has focused on undergraduate students. It is equally important to understand the impact of financial aid on graduate students, particularly since graduate students incur much higher levels of debt due to their prolonged time in higher education and because the rate…

  9. Space-time clustering characteristics of dengue based on ecological, socio-economic and demographic factors in northern Sri Lanka.

    PubMed

    Anno, Sumiko; Imaoka, Keiji; Tadono, Takeo; Igarashi, Tamotsu; Sivaganesh, Subramaniam; Kannathasan, Selvam; Kumaran, Vaithehi; Surendran, Sinnathamby Noble

    2015-01-01

    The aim of the present study was to identify geographical areas and time periods of potential clusters of dengue cases based on ecological, socio-economic and demographic factors in northern Sri Lanka from January 2010 to December 2013. Remote sensing (RS) was used to develop an index comprising rainfall, humidity and temperature data. Remote sensing data gathered by the AVNIR-2 instrument onboard the ALOS satellite were used to detect urbanisation, and a digital land cover map was used to extract land cover information. Other data on relevant factors and dengue outbreaks were collected through institutions and extant databases. The analysed RS data and databases were integrated into a geographical information system (GIS) enabling space-time clustering analysis. Our results indicate that increases in the number of combinations of ecological, socio-economic and demographic factors that are present or above the average contribute to significantly high rates of space-time dengue clusters. The spatio-temporal association that consolidates the two kinds of associations into one can ensure a more stable model for forecasting. An integrated spatiotemporal prediction model at a smaller level using ecological, socioeconomic and demographic factors could lead to substantial improvements in dengue control and prevention by allocating the right resources to the appropriate places at the right time. PMID:26618322

  10. Variations on a Theme: Characteristics of Out-of-School Time Science Programs Offered by Distinct Organization Types

    ERIC Educational Resources Information Center

    Laursen, Sandra L.; Thiry, Heather; Archie, Tim; Crane, Rebecca

    2013-01-01

    The out-of-school time (OST) domain offers a promising resource for enriching young people's experience of science, technology, and engineering. Belief is widespread that OST programs are ideal locations in which to learn science and that youth participation may increase access to science for underrepresented groups, such as girls or minorities,…

  11. Interlibrary Loan Turnaround Time: A Study of Performance Characteristics of the University of California, Berkeley Interlibrary Loan Lending Operation.

    ERIC Educational Resources Information Center

    Martell, Charles R., Jr.

    Data from the interlibrary loan lending office files at the University of California, Berkeley for 1971-1972 were examined in order to determine the pattern of interlibrary loan traffic with other University of California and California State Universities and Colleges (CSUC) in Northern California. Turnaround time for the average Sacramento State…

  12. The effects of Bombyx mori silk strain and extraction time on the molecular and biological characteristics of sericin.

    PubMed

    Siritientong, Tippawan; Bonani, Walter; Motta, Antonella; Migliaresi, Claudio; Aramwit, Pornanong

    2016-01-01

    Sericin was extracted from three strains of Thai Bombyx mori silk cocoons (white shell Chul1/1, greenish shell Chul3/2, and yellow shell Chul4/2) by a high-pressure and high-temperature technique. The characteristics of sericin extracted from different fractions (15, 45, and 60 min extraction process) were compared. No differences in amino acid composition were observed among the three fractions. For all silk strains, sericin extracted from a 15-min process presented the highest molecular weight. The biological potential of the different sericin samples as a bioadditive for 3T3 fibroblast cells was assessed. When comparing sericin extracted from three silk strains, sericin fractions extracted from Chul4/2 improved cell proliferation, while sericin from Chul 1/1 activated Type I collagen production to the highest extent. This study allows the natural variability of sericin obtained from different sources and extraction conditions to be addressed and provides clues for the selection of sericin sources. PMID:26399155

  13. Real-time analysis of endogenous protoporphyrin IX fluorescence from δ-aminolevulinic acid and its derivatives reveals distinct time- and dose-dependent characteristics in vitro

    NASA Astrophysics Data System (ADS)

    Kiesslich, Tobias; Helander, Linda; Illig, Romana; Oberdanner, Christian; Wagner, Andrej; Lettner, Herbert; Jakab, Martin; Plaetzer, Kristjan

    2014-08-01

    Photodynamic therapy (PDT) and photodiagnosis based on the intracellular production of the photosensitizer protoporphyrin IX (PPIX) by administration of its metabolic precursor δ-aminolevulinic acid (ALA) achieved their breakthrough upon the clinical approval of MAL (ALA methyl ester) and HAL (ALA hexyl ester). For newly developed ALA derivatives or application in new tumor types, in vitro determination of PPIX formation involves multiparametric experiments covering variable pro-drug concentrations, medium composition, time points of analysis, and cell type(s). This study uses a fluorescence microplate reader with a built-in temperature and atmosphere control to investigate the high-resolution long-term kinetics (72 h) of cellular PPIX fueled by administration of either ALA, MAL, or HAL for each 10 different concentrations. For simultaneous proliferation correction, A431 cells were stably transfected with green fluorescent protein. The results indicate that the peak PPIX level is a function of both, incubation concentration and period: maximal PPIX is generated with 1 to 2-mM ALA/MAL or 0.125-mM HAL; also, the PPIX peak shifts to longer incubation periods with increasing pro-drug concentrations. The results underline the need for detailed temporal analysis of PPIX formation to optimize ALA (derivative)-based PDT or photodiagnosis and highlight the value of environment-controlled microplate readers for automated in vitro analysis.

  14. Real-time optical-fibre luminescence dosimetry for radiotherapy: physical characteristics and applications in photon beams.

    PubMed

    Aznar, Marianne C; Andersen, Claus E; Bøtter-Jensen, Lars; Bäck, Sven A J; Mattsson, Sören; Kjaer-Kristoffersen, Flemming; Medin, Joakim

    2004-05-01

    A new optical-fibre radiation dosimeter system, based on radioluminescence and optically stimulated luminescence from carbon-doped aluminium oxide, was developed and tested in clinical photon beams. This prototype offers several features, such as a small detector (1 x 1 x 2 mm3), high sensitivity, real-time read-out and the ability to measure both dose rate and absorbed dose. The measurements describing reproducibility and output dependence on dose rate, field size and energy all had standard deviations smaller than 1%. The signal variation with the angle of incidence was smaller than 2% (1 SD). Measurements performed in clinical situations suggest the potential of using this real-time system for in vivo dosimetry in radiotherapy. PMID:15152922

  15. A Methodology for Flight-Time Identification of Helicopter-Slung Load Frequency Response Characteristics Using CIFER

    NASA Technical Reports Server (NTRS)

    Sahai, Ranjana; Pierce, Larry; Cicolani, Luigi; Tischler, Mark

    1998-01-01

    Helicopter slung load operations are common in both military and civil contexts. The slung load adds load rigid body modes, sling stretching, and load aerodynamics to the system dynamics, which can degrade system stability and handling qualities, and reduce the operating envelope of the combined system below that of the helicopter alone. Further, the effects of the load on system dynamics vary significantly among the large range of loads, slings, and flight conditions that a utility helicopter will encounter in its operating life. In this context, military helicopters and loads are often qualified for slung load operations via flight tests which can be time consuming and expensive. One way to reduce the cost and time required to carry out these tests and generate quantitative data more readily is to provide an efficient method for analysis during the flight, so that numerous test points can be evaluated in a single flight test, with evaluations performed in near real time following each test point and prior to clearing the aircraft to the next point. Methodology for this was implemented at Ames and demonstrated in slung load flight tests in 1997 and was improved for additional flight tests in 1999. The parameters of interest for the slung load tests are aircraft handling qualities parameters (bandwidth and phase delay), stability margins (gain and phase margin), and load pendulum roots (damping and natural frequency). A procedure for the identification of these parameters from frequency sweep data was defined using the CIFER software package. CIFER is a comprehensive interactive package of utilities for frequency domain analysis previously developed at Ames for aeronautical flight test applications. It has been widely used in the US on a variety of aircraft, including some primitive flight time analysis applications.

  16. X-ray Variability Characteristics of the Narrow line SEYFERT 1 MKN 766 I: Energy Dependent Timing Properties

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Turner, T. J.; Papadakis, I.; Arevalo, P.; Reeves, J. N.; Miller, L.

    2007-01-01

    We present the energy-dependent power spectral density (PSD) and cross-spectral properties of Mkn 766 obtained from a six-revolution XMM-Newton observation in 2005. The resulting PSDs, which have highest temporal frequency resolution for an AGN PSD to date, show breaks which increase in temporal frequency as photon energy increases; break frequencies differ by an average of approx.0.4 in the log between the softest and hardest bands. The consistency of the 2001 and 2005 observations variability properties, namely PSD shapes and the linear rms-flux relation, suggests the 2005 observation is simply a low-flux extension of the 2001 observation. The coherence function is measured to be approx.0.6-0.9 at temporal frequencies below the PSD break, and is lower for relatively larger energy band separation; coherence also drops significantly towards zero above the PSD break frequency. Temporal frequency-dependent soft-to-hard time lags are detected in this object for the first time: lags increase towards longer time scales and as energy separation increases. Cross-spectral properties are the thus consistent with previous measurements for Mkn 766 (Vaughan & Fabian 2003) and other accreting black hole systems. The results are discussed in the context of several variability models, including those based on inwardly-propagating viscosity variations in the accretion disk.

  17. Characteristics of official and experimental GRACE time series by GFZ and CSR - with applications to polar signals

    NASA Astrophysics Data System (ADS)

    Horvath, Alexander; Horwath, Martin; Pail, Roland

    2014-05-01

    The Release-05 monthly solutions by the three centers of the GRACE Science and Data System are a significant improvement with respect to the previous Release 4. Meanwhile, previous assessments have revealed different noise levels between the solutions by CSR, GFZ and JPL, and also different amplitudes of interannual signal in the solutions by GFZ as compared to the two other centers. Encouraged by the science community, GFZ and CSR have kindly provided additional sets of time series. GFZ has reprocessed the RL05 monthly solutions (up to degree and order 90) with revised processing. CSR has made available monthly solutions with standard processing up to degree and order 96, in addition to their solutions up to degree and order 60. We compare these different time series with respect to their signal and noise content and analyze them on global and regional scale. For the regional scale our special interest is paid on Antarctica and on revealing polar signals such as ice mass trends and GIA. Following the necessity of destriping, an optimal choice for the setup of the Swenson & Wahr filter approach is evaluated to adapt to the specific signal and noise level in Antarctica. Furthermore we analyze the potential benefit of mixed time series solutions in order to combine the strengths of the solutions available. Concerning the question for an optimal maximum degree we suggest that for resolving large polar ice mass changes, it would be beneficial to provide gravity field variations even beyond degree 90.

  18. Circadian regulation of human sleep and age-related changes in its timing, consolidation and EEG characteristics

    NASA Technical Reports Server (NTRS)

    Dijk, D. J.; Duffy, J. F.

    1999-01-01

    The light-entrainable circadian pacemaker located in the suprachiasmatic nucleus of the hypothalamus regulates the timing and consolidation of sleep by generating a paradoxical rhythm of sleep propensity; the circadian drive for wakefulness peaks at the end of the day spent awake, ie close to the onset of melatonin secretion at 21.00-22.00 h and the circadian drive for sleep crests shortly before habitual waking-up time. With advancing age, ie after early adulthood, sleep consolidation declines, and time of awakening and the rhythms of body temperature, plasma melatonin and cortisol shift to an earlier clock hour. The variability of the phase relationship between the sleep-wake cycle and circadian rhythms increases, and in old age sleep is more susceptible to internal arousing stimuli associated with circadian misalignment. The propensity to awaken from sleep advances relative to the body temperature nadir in older people, a change that is opposite to the phase delay of awakening relative to internal circadian rhythms associated with morningness in young people. Age-related changes do not appear to be associated with a shortening of the circadian period or a reduction of the circadian drive for wake maintenance. These changes may be related to changes in the sleep process itself, such as reductions in slow-wave sleep and sleep spindles as well as a reduced strength of the circadian signal promoting sleep in the early morning hours. Putative mediators and modulators of circadian sleep regulation are discussed.

  19. Enhanced fluorescence and structural characteristics of carboxymethyl cellulose/Eu(III) nano-complex: Influence of reaction time.

    PubMed

    Ye, Jun; Wang, Ben; Xiong, Jian; Sun, Runcang

    2016-01-01

    CMC/Eu(III) nano-complexes were synthesized by reacting Eu(3+) with carboxymethyl cellulose (CMC). The SEM and EDS showed that particle size was less than 100nm and evenly distributed. FTIR and XPS indicated that the oxygen atoms in COO (-), OH, and COC were involved in the complexation with Eu(3+), yet, the O atoms were involved in different positions on anhydroglucose rings depending on reaction time. It was found that there were good energy matches between energy levels on ground state of CMC and (5)D0 Eu(III). Moreover, the intensities of (5)D0→(7)F2 of the nano-complexes were stronger than that of (5)D0→(7)F1, which indicated that the Eu(III) was not in the center of symmetry. The optimized reaction time was 35min, at this reaction time the smallest particle size and uniform distribution was obtained, the coordination structure was advantageous for the energy absorption transfer and emission. PMID:26453851

  20. Characteristics of time-varying intracranial pressure on blood flow through cerebral artery: A fluid-structure interaction approach.

    PubMed

    Syed, Hasson; Unnikrishnan, Vinu U; Olcmen, Semih

    2016-02-01

    Elevated intracranial pressure is a major contributor to morbidity and mortality in severe head injuries. Wall shear stresses in the artery can be affected by increased intracranial pressures and may lead to the formation of cerebral aneurysms. Earlier research on cerebral arteries and aneurysms involves using constant mean intracranial pressure values. Recent advancements in intracranial pressure monitoring techniques have led to measurement of the intracranial pressure waveform. By incorporating a time-varying intracranial pressure waveform in place of constant intracranial pressures in the analysis of cerebral arteries helps in understanding their effects on arterial deformation and wall shear stress. To date, such a robust computational study on the effect of increasing intracranial pressures on the cerebral arterial wall has not been attempted to the best of our knowledge. In this work, fully coupled fluid-structure interaction simulations are carried out to investigate the effect of the variation in intracranial pressure waveforms on the cerebral arterial wall. Three different time-varying intracranial pressure waveforms and three constant intracranial pressure profiles acting on the cerebral arterial wall are analyzed and compared with specified inlet velocity and outlet pressure conditions. It has been found that the arterial wall experiences deformation depending on the time-varying intracranial pressure waveforms, while the wall shear stress changes at peak systole for all the intracranial pressure profiles. PMID:26701867

  1. Characteristics of B2O3 and Fe added into BaFe12O19 permanent magnets prepared at different milling time and sintering temperature

    NASA Astrophysics Data System (ADS)

    Sebayang, Perdamean; Sari, Ayu Yuswita; Ginting, Delovita; Allan, Yola; Nasruddin M., N.; Sebayang, Kerista

    2016-02-01

    The objective of present work is to investigate the characteristic of BaFe12O19, B2O3-BaFe12O19 and Fe-BaFe12O19 magnets fabricated at different milling time and sintering temperature. The characteristic of perrmanen magnet BaFe12O19 with different content of B2O3 and Fe which was fabricated at different milling time and sintering temperature were investigated. The powder mixtures were prepared by dry and wet milling at various milling time. The powder were mixtured and prepared by dry and wet milling at various milling time. The mixture powder was then compacted by anisotropic with compressive pressure of 50 N/cm2. The green bodies were sinter at 1050, 1100, 1150 and 1200°C and hold for 1 h, separately. The density, magnetic flux density and B-H curve were measured by Archimedes principle, Gauss meter and Permagraph, respectively. The microstructure and phase composition characterization were performed by SEM and XRD. The results of this study are presented in this paper. It shows that addition of Fe (in wet milling) and B2O3 (in dry milling) respectively give a potential benefit to reduce the sintering temperature and improve the magnetic flux density of barium hexaferrite.

  2. Calibrating passive acoustic monitoring: correcting humpback whale call detections for site-specific and time-dependent environmental characteristics.

    PubMed

    Helble, Tyler A; D'Spain, Gerald L; Campbell, Greg S; Hildebrand, John A

    2013-11-01

    This paper demonstrates the importance of accounting for environmental effects on passive underwater acoustic monitoring results. The situation considered is the reduction in shipping off the California coast between 2008-2010 due to the recession and environmental legislation. The resulting variations in ocean noise change the probability of detecting marine mammal vocalizations. An acoustic model was used to calculate the time-varying probability of detecting humpback whale vocalizations under best-guess environmental conditions and varying noise. The uncorrected call counts suggest a diel pattern and an increase in calling over a two-year period; the corrected call counts show minimal evidence of these features. PMID:24181982

  3. Effect of Annealing Time on Microstructural Evolution and Deformation Characteristics in 10Mn1.5Al TRIP Steel

    NASA Astrophysics Data System (ADS)

    Han, Qihang; Zhang, Yulong; Wang, Li

    2015-05-01

    To investigate microstructural evolution and its effects on the deformation behaviors of cold-rolled 10Mn1.5Al TRIP steel, a series of intercritical annealing treatments with various holding times from 3 minutes to 48 hours were conducted. With the increase of the holding time from 3 minutes to 12 hours, the elongation was improved from 15 to 42 pct, while the tensile strength was only reduced from 1210 to 1095 MPa; the strength-ductility combination thus exceeded 45 GPa pct. Austenite was found to coexist with martensite within deformed grains, which reduced the strain concentration at the interface. The austenite transformation fraction, as measured from the {220} peaks, after 3 minutes annealing was half that after 12 hours annealing. This is an indication that the slip systems were more easily activated in the micro-scaled grains compared with nano-scaled grains. Therefore, although the stability of austenite would have increased during annealing, size-induced slip suppression was reduced. Thus, more strain was accommodated in the austenite, facilitating a greater strain-induced transformation and better ductility.

  4. The Energy-Dependent X-Ray Timing Characteristics of the Narrow Line Seyfert 1 MKN 766

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Papadakis, I.; Arevalo, P.; Turner, T. J.; Miller, L.; Reeves, J. N.

    2007-01-01

    We present the energy-dependent power spectral density (PSD) and cross-spectral properties of Mkn 766, obtained from combining data obtained during an XMM-Newton observation spanning six revolutions in 2005 with data obtained from an XMM-Newton long-look in 2001. The PSD shapes and rms-flux relations are found to be consistent between the 2001 and 2005 observations, suggesting the 2005 observation is simply a low-flux extension of the 2001 observation and permitting us to combine the two data sets. The resulting PSD has the highest temporal frequency resolution for any AGN PSD measured to date. Applying a broken power-law model yields break frequencies which increase in temporal frequency with photon energy. Obtaining a good fit when assuming energy-independent break frequencies requires the presence of a Lorentzian at 4.6 +/- 0.4 x 10(exp -4)Hz whose strength increases with photon energy, a behavior seen in black hole X-ray binaries. The cross-spectral properties are measured; temporal frequency-dependent soft-to-hard time lags are detected in this object for the first time. Cross-spectral results are consistent with those for other accreting black hole systems. The results are discussed in the context of several variability models, including those based on inwardly-propagating viscosity variations in the accretion disk.

  5. Effects of cutting time, stump height, parent tree characteristics, and harvest variables on development of bigleaf maple sprout clumps

    USGS Publications Warehouse

    Tappeiner, J. C., II; Zasada, J.; Maxwell, B.

    1996-01-01

    In order to determine the effects of stump height, year of cutting, parent-tree size, logging damage, and deer browsing on bigleaf maple (Acer macrophyllum) sprout clump development, maple trees were cut to two stump heights at three different times. Stump height had the greatest impact on sprout clump size. Two years after clearcutting, the sprout clump volume for short stumps was significantly less than that for tall stumps. The sprout clump volume, area, and number of sprouts were significantly less for trees cut 1 and 2 yr before harvest than for trees cut at harvest. Sprout clump size was positively correlated with parent tree stem diameter and stump volume, and negatively correlated with the percentage of bark removed during logging. Browsing had no significant impact on average clump size. Uncut trees produced sprout clumps at their base and epicormic branches along the length of their stems; thus their crown volume averaged four to five times that of cut trees. Cutting maple in clearcuts to low stumps may reduce maple competition with Douglas-fir regeneration and still maintain maple in the next stand.

  6. A time-series model of phase amplitude cross frequency coupling and comparison of spectral characteristics with neural data.

    PubMed

    Lepage, Kyle Q; Vijayan, Sujith

    2015-01-01

    Stochastic processes that exhibit cross-frequency coupling (CFC) are introduced. The ability of these processes to model observed CFC in neural recordings is investigated by comparison with published spectra. One of the proposed models, based on multiplying a pulsatile function of a low-frequency oscillation (θ) with an unobserved and high-frequency component, yields a process with a spectrum that is consistent with observation. Other models, such as those employing a biphasic pulsatile function of a low-frequency oscillation, are demonstrated to be less suitable. We introduce the full stochastic process time series model as a summation of three component weak-sense stationary (WSS) processes, namely, θ, γ, and η, with η a 1/f (α) noise process. The γ process is constructed as a product of a latent and unobserved high-frequency process x with a function of the lagged, low-frequency oscillatory component (θ). After demonstrating that the model process is WSS, an appropriate method of simulation is introduced based upon the WSS property. This work may be of interest to researchers seeking to connect inhibitory and excitatory dynamics directly to observation in a model that accounts for known temporal dependence or to researchers seeking to examine what can occur in a multiplicative time-domain CFC mechanism. PMID:25866758

  7. Storage capacity, detention time, and selected sediment deposition characteristics for Gull and Silver Lakes, Mono County, California

    USGS Publications Warehouse

    Blodgett, J.C.

    1996-01-01

    Bathymetric surveys made in September 1994 indicate the maximum storage capacity of Gull and Silver Lakes, California, is about 2,400 and 3,000 acre-feet, respectively. During March through October 1994, the lake level dropped 0.7 feet at both Gull Lake and Silver Lake. The associated change in storage was 60 acre-feet at Gull Lake and 80 acre-feet at Silver Lake. The flow detention time for average annual flow conditions at Gull Lake is about 2.5 years and for Silver Lake, the average detention time is about 19 days. Sediment deposition at the inlet to Silver Lake has been monitored since 1951 using aerial photography. During 1963 through 1994, the area of sediment deposition increased from 0.32 to about 2.4 acres. Analyses of these data indicate that the rate of deposition was lower during 1951-72 than the rate during 1973-94. Sediment deposition at the lake inlet is a continuing phenomenon.

  8. Effect of cationic surfactants on characteristics and colorimetric behavior of polydiacetylene/silica nanocomposite as time-temperature indicator

    NASA Astrophysics Data System (ADS)

    Nopwinyuwong, Atchareeya; Kitaoka, Takuya; Boonsupthip, Waraporn; Pechyen, Chiravoot; Suppakul, Panuwat

    2014-09-01

    Polydiacetylene (PDA)/silica nanocomposites were synthesized by self-assembly method using polymerizable amphiphilic diacetylene monomers, 10,12-pentacosadiynoic acid (PCDA). Addition of cationic surfactants (PDADMAC and CTAB) to PDA/SiO2 nanocomposites induced higher intermolecular force which affected their size, shape and color transition. Pure PDA, PDA/SiO2, PDA/SiO2/PDADMAC and PDA/SiO2/CTAB were investigated by particle size analysis, TEM, SEM, UV-vis spectroscopy and FT-IR. It was found that the PDA/SiO2 nanocomposites exhibited slightly larger particle sizes than those of other samples. The PDA/SiO2 nanocomposites with a core-shell structure were almost regarded as spherical-shaped particles. Cationic surfactants, especially CTAB, presumably affected the particle size and shape of PDA/SiO2 nanocomposites due to the disruption of hydrogen bonding between PDA head group and ammonium group. The colorimetric response of both PDA/SiO2/surfactant and surfactant-free PDA/SiO2 aqueous solutions directly changed in relation to time and temperature; thus they were expected to be applied as a new polymer-based time-temperature indicator (TTI).

  9. Influence of autoignition delay time characteristics of different fuels on pressure waves and knock in reciprocating engines

    SciTech Connect

    Bradley, D.; Kalghatgi, G.T.

    2009-12-15

    The functional relationship of autoignition delay time with temperature and pressure is employed to derive the propagation velocities of autoignitive reaction fronts for particular reactivity gradients, once autoignition has been initiated. In the present study of a variety of premixtures, with different functional relationships, such gradients comprise fixed initial temperature gradients. The smaller is the ratio of the acoustic speed through the mixture to the localised velocity of the autoignitive front, the greater are the amplitude and frequency of the induced pressure wave. This might lead to damaging engine knock. At higher values of the ratio, the autoignition can be benign with only small over-pressures. This approach to the effects of autoignition is confirmed by its application to a variety of experimental studies involving: (i)Imposed temperature gradients in a rapid compression and expansion machine. (ii)Onset of knock in an engine with advancing spark timing. (iii)Development of autoignition at a single hot spot in an engine. (iv)Autoignition fronts initiated by several hot spots. There is much diversity in the effects that can be produced by different fuels in different ranges of temperature and pressure. Higher values of autoignitive propagation speeds lead to increasingly severe engine knock. Such effects cannot always be predicted from the Research and Motor octane numbers. (author)

  10. Characteristics of microbial communities in steppe paleosols buried under kurgans of the Sarmatian time (I-IV centuries AD)

    NASA Astrophysics Data System (ADS)

    Demkina, T. S.; Khomutova, T. E.; Kashirskaya, N. N.; Stretovich, I. V.; Demkin, V. A.

    2009-07-01

    Microbiological studies of paleosols buried under steppe kurgans of different ages of the Middle (I-II centuries AD) and Late Sarmatian (II-IV centuries AD) time in different regions of the Lower Volga steppes were carried out. The regularities of the soil microbial communities’ development were determined in the I-IV centuries AD by the climate dynamics and the replacement of the relatively humid conditions (the I century to the first half of the II century) by dry (the second half of the II century to the first half of the III century) and then again by humid (the end of the III century to the IV century) conditions. In the humid climatic periods, the active biomass of the microorganisms and its portion in the total microbial biomass and the Corg of the soil increased, the portion of microorganisms consuming plant residues increased in the ecological-trophic structure of the microbial community, and the index of oligotrophy decreased. These changes had an opposite direction in the arid climatic periods. The variations of the microbiological parameters relative to the century-long dynamics of the climate over the historical time were synchronous and unidirectional, though the studied soils were found in different soil-geographical zones (dry and desert steppe), natural regions (the Privolzhskaya and Ergeni uplands and the Caspian Lowland), and landforms (watersheds, river terraces, marine plains).

  11. Improvements of Real Time First Motion Focal Mechanism and Noise Characteristics of New Sites at the Puerto Rico Seismic Network

    NASA Astrophysics Data System (ADS)

    Williams, D. M.; Lopez, A. M.; Huerfano, V.; Lugo, J.; Cancel, J.

    2011-12-01

    Seismic networks need quick and efficient ways to obtain information related to seismic events for the purposes of seismic activity monitoring, risk assessment, and scientific knowledge among others. As part of an IRIS summer internship program, two projects were performed to provide a tool for quick faulting mechanism and improve seismic data at the Puerto Rico Seismic Network (PRSN). First, a simple routine to obtain a focal mechanisms, the geometry of the fault, based on first motions was developed and implemented for data analysts routine operations at PRSN. The new tool provides the analyst a quick way to assess the probable faulting mechanism that occurred while performing the interactive earthquake location procedure. The focal mechanism is generated on-the-fly when data analysts pick P wave arrivals onsets and motions. Once first motions have been identified, an in-house PRSN utility is employed to obtain the double couple representation and later plotted using GMT's psmeca utility. Second, we addressed the issue of seismic noise related to thermal fluctuations inside seismic vaults. Seismic sites can be extremely noisy due to proximity to cultural activities and unattended thermal fluctuations inside sensor housings, thus resulting in skewed readings. In the past, seismologists have used different insulation techniques to reduce the amount of unwanted noise that a seismometers experience due to these thermal changes with items such as Styrofoam, and fiber glass among others. PRSN traditionally uses Styrofoam boxes to cover their seismic sensors, however, a proper procedure to test how these method compare to other new techniques has never been approached. The deficiency of properly testing these techniques in the Caribbean and especially Puerto Rico is that these thermal fluctuations still happen because of the intense sun and humidity. We conducted a test based on the methods employed by the IRIS Transportable Array, based on insulation by sand burial of the sensor. Two Guralps CMG-3T's connected to RefTek's 150 digitizers were used at PRSN's MPR site seismic vault to compare the two types of insulation. Two temperature loggers were placed along each seismic sensor for a period of one week to observe how much thermal fluctuations occur in each insulation method and then compared its capability for noise reduction due to thermal fluctuations. With only a single degree Celsius fluctuation inside the sand (compared to almost twice that value for the foam) the sensor buried in sand provided the best insulation for the seismic vault. In addition, the quality of the data was analyzed by comparing both sensors using PQLX. We show results of this analysis and also provide a site characteristic of new stations to be included in the daily earthquake location operations at the PRSN.

  12. Influence of multi-deposition multi-annealing on time-dependent dielectric breakdown characteristics of PMOS with high-k/metal gate last process

    NASA Astrophysics Data System (ADS)

    Wang, Yan-Rong; Yang, Hong; Xu, Hao; Wang, Xiao-Lei; Luo, Wei-Chun; Qi, Lu-Wei; Zhang, Shu-Xiang; Wang, Wen-Wu; Yan, Jiang; Zhu, Hui-Long; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2015-11-01

    A multi-deposition multi-annealing technique (MDMA) is introduced into the process of high-k/metal gate MOSFET for the gate last process to effectively reduce the gate leakage and improve the device’s performance. In this paper, we systematically investigate the electrical parameters and the time-dependent dielectric breakdown (TDDB) characteristics of positive channel metal oxide semiconductor (PMOS) under different MDMA process conditions, including the deposition/annealing (D&A) cycles, the D&A time, and the total annealing time. The results show that the increases of the number of D&A cycles (from 1 to 2) and D&A time (from 15 s to 30 s) can contribute to the results that the gate leakage current decreases by about one order of magnitude and that the time to fail (TTF) at 63.2% increases by about several times. However, too many D&A cycles (such as 4 cycles) make the equivalent oxide thickness (EOT) increase by about 1 Å and the TTF of PMOS worsen. Moreover, different D&A times and numbers of D&A cycles induce different breakdown mechanisms. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601) and the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129).

  13. Characteristics of DNA-AuNP networks on cell membranes and real-time movies for viral infection.

    PubMed

    Li, Chunmei; Zheng, Linling; Yang, Xiaoxi; Wan, Xiaoyan; Wu, Wenbi; Zhen, Shujun; Li, Yuanfang; Luo, Lingfei; Huang, Chengzhi

    2016-03-01

    This data article provides complementary data for the article entitled "DNA-AuNP networks on cell membranes as a protective barrier to inhibit viral attachment, entry and budding" Li et al. (2016) [1]. The experimental methods for the preparation and characterization of DNA-conjugated nanoparticle networks on cell membranes were described. Confocal fluorescence images, agarose gel electrophoresis images and hydrodynamic diameter of DNA-conjugated gold nanoparticle (DNA-AuNP) networks were presented. In addition, we have prepared QDs-labeled RSV (QDs-RSV) to real-time monitor the RSV infection on HEp-2 cells in the absence and presence of DNA-AuNP networks. Finally, the cell viability of HEp-2 cells coated by six types of DNA-nanoparticle networks was determined after RSV infection. PMID:26909382

  14. Characteristics of DNA-AuNP networks on cell membranes and real-time movies for viral infection

    PubMed Central

    Li, Chunmei; Zheng, Linling; Yang, Xiaoxi; Wan, Xiaoyan; Wu, Wenbi; Zhen, Shujun; Li, Yuanfang; Luo, Lingfei; Huang, Chengzhi

    2016-01-01

    This data article provides complementary data for the article entitled “DNA-AuNP networks on cell membranes as a protective barrier to inhibit viral attachment, entry and budding” Li et al. (2016) [1]. The experimental methods for the preparation and characterization of DNA-conjugated nanoparticle networks on cell membranes were described. Confocal fluorescence images, agarose gel electrophoresis images and hydrodynamic diameter of DNA-conjugated gold nanoparticle (DNA-AuNP) networks were presented. In addition, we have prepared QDs-labeled RSV (QDs-RSV) to real-time monitor the RSV infection on HEp-2 cells in the absence and presence of DNA-AuNP networks. Finally, the cell viability of HEp-2 cells coated by six types of DNA-nanoparticle networks was determined after RSV infection. PMID:26909382

  15. Egg laying characteristics, egg weight, embryo development, hatching weight and post-hatch growth in relation to oviposition time of broiler breeders.

    PubMed

    Akil, R; Zakaria, A H

    2015-05-01

    Two experiments were conducted to determine egg laying characteristics and the effects of oviposition time on egg weight, embryo development and post-hatch growth in broiler breeders. In experiment 1, eggs collected for 3 consecutive days on hourly basis between 06:30 and 17:30h were categorized to early, middle and late oviposition times in the clutch. In experiment 2, eggs were incubated to study embryo development, remaining albumen, liver weight, heart weight and the tibia length of embryos at 12, 14, 16 and 18 days of incubation as well as the body weight of hatchlings and chickens at 7, 21 and 42 days of age in relation to oviposition time. About 76% of nest eggs were laid from 06:30 to 11:30h. A similar pattern was observed in floor eggs. Egg weight decreased (P<0.01) with advanced position in the clutch. Generally, oviposition time had no effect on embryo growth parameters. At hatch, body weight of chicks derived from eggs of late oviposition times was less (P<0.01) than that of chicks from eggs produced earlier in the clutch. From 3-week-old onwards, chickens of early oviposition time sustained heavier (P<0.05) weight than chickens of middle oviposition time whereas chickens of late oviposition time obtained a middle weight. Differences in egg weights, body weight at hatch and post-hatch growth due to time of oviposition suggest that oviposition time together with incubation conditions should be considered for obtaining greater uniformity and growth of chickens. PMID:25818523

  16. Effects of pressure and deposition time on the characteristics of In2Se3 films grown by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Yan, Yong; Li, Shasha; Ou, Yufeng; Ji, Yaxin; Yu, Zhou; Liu, Lian; Yan, Chuanpeng; Zhang, Yong; Zhao, Yong

    2014-11-01

    Crystalline In2Se3 films were fabricated by magnetron sputtering from a sintered In2Se3-compound target and the effects of the deposition parameters, including the working pressure and deposition time, on the phase composition, structure, morphology, and optical properties were clarified. Single-phase κ-In2Se3 was prepared at 4.0 Pa, but γ-In2Se3 was recognized when the working pressure was lower than 4.0 Pa. The optical transmittance of the films decreased to 45% and the optical band gap varied from 2.9 to 2.0 eV with increasing film thickness from 80 to 967 nm. Metal-semiconductor-metal (MSM) photodetectors based on γ-In2Se3 thin films with various thicknesses were also fabricated. The result of photosensitivity research on such MSM photodetectors suggests that it may be impossible to fabricate wide-absorption-range MSM devices by just using a single material ( γ-In2Se3) because of spatial potential fluctuations in the layers. [Figure not available: see fulltext.

  17. Real-time digital data-acquisition system for determining load characteristics. Volume 2: Operating, programming and maintenance instructions

    NASA Astrophysics Data System (ADS)

    Podesto, B.; Lapointe, A.; Larose, G.; Robichaud, Y.; Vaillancourt, C.

    1981-03-01

    The design and construction of a Real-Time Digital Data Acquisition System (RTDDAS) to be used in substations for on-site recording and preprocessing load response data were included. The gathered data can be partially processed on site to compute the apparent, active and reactive powers, voltage and current rms values, and instantaneous values of phase voltages and currents. On-site processing capability is provided for rapid monitoring of the field data to ensure that the test setup is suitable. Production analysis of field data is accomplished off-line on a central computer from data recorded on a dual-density (800/1600) magnetic tape which is IBM-compatible. Parallel channels of data can be recorded at a variable rate from 480 to 9000 samples per second per channel. The RTDDAS is housed in a 9.1 m (30-ft) trailer which is shielded from electromagnetic interference and protected by isolators from switching surges. The test must sometimes be performed. Information pertaining to the installation, software operation, and maintenance is presented.

  18. Global Characteristics of the Correlation and Time Lag Between Solar and Ionospheric Parameters in the 27-day Period

    NASA Technical Reports Server (NTRS)

    Lee, Choon-Ki; Han, Shin-Chan; Dieter,Bilitza; Ki-Weon,Seo

    2012-01-01

    The 27-day variations of topside ionosphere are investigated using the in-situ electron density measurements from the CHAMP planar Langmuir probe and GRACE K-band ranging system. As the two satellite systems orbit at the altitudes of approx. 370 km and approx. 480 km, respectively, the satellite data sets are greatly valuable for examining the electron density variations in the vicinity of F2-peak. In a 27-day period, the electron density measurements from the satellites are in good agreements with the solar flux, except during the solar minimum period. The time delays are mostly 1-2 day and represent the hemispherical asymmetry. The globally-estimated spatial patterns of the correlation between solar flux and in-situ satellite measurements show poor correlations in the (magnetic) equatorial region, which are not found from the ground measurements of vertically-integrated electron content. We suggest that the most plausible cause for the poor correlation is the vertical movement of ionization due to atmospheric dynamic processes that is not controlled by the solar extreme ultraviolet radiation.

  19. Over time and space changing characteristics of estuarine suspended particles in the German Weser and Elbe estuaries

    NASA Astrophysics Data System (ADS)

    Papenmeier, Svenja; Schrottke, Kerstin; Bartholomä, Alexander

    2014-01-01

    Fine cohesive, suspended sediments appear in all estuarine environments in a predominately flocculated state. The transport and deposition of these flocs is influenced by their in-situ and primary particle size distribution. Especially the size of the inorganic particles influences the density and hence the settling velocity of the flocculated material. To describe both the changes in primary particle size of suspended particulate matter as well as the variability of floc sizes over time and space, the data of In-Situ Particle-Size Distributions (ISPSDs), Primary Particle Size Distributions (PPSDs) and Suspended Sediment Concentrations (SSCs) were collected. For this, Laser In-Situ Scattering and Transmissiometry (LISST) measurements as well as the water samples were collected in the German Elbe and Weser estuaries, covering seasonal variability of the SSC. The data of the ISPSDs show that the inorganic and organic Suspended Particulate Matter (SPM), as found in the Elbe and Weser estuaries, mostly appears in a flocculated state. The substrate for organic matter is mainly imported from the seaside and transported into the estuaries as indicated by an upstream decrease of the amount of fine particles. In winter, when the freshwater discharge is high, different PPSDs are found in the case of the Elbe estuary in the Turbidity Maximum Zone (TMZ) as well as in the landward and in the seaward sections close to the TMZ. In summer, the distance between the seaward and the landward section is too low to obtain an individual PPSD within the Elbe TMZ. A missing correlation between the PPSD and ISPSD shows that the inorganic constituents do not have an influence on the in-situ floc size. Although flocs aggregate and disaggregate over a tidal cycle and with changing SSC, they do not change their PPSD. The microflocs are therefore strong enough to withstand further breakage into their inorganic constituents.

  20. Effect of gamma irradiation and storage time on microbial growth and physicochemical characteristics of pumpkin (Cucurbita Moschata Duchesne ex Poiret) puree.

    PubMed

    Gliemmo, Mara F; Latorre, Mara E; Narvaiz, Patricia; Campos, Carmen A; Gerschenson, La N

    2014-01-01

    The effect of gamma irradiation (0-2?kGy) and storage time (0-28 days) on microbial growth and physicochemical characteristics of a packed pumpkin puree was studied. For that purpose, a factorial design was applied. The puree contained potassium sorbate, glucose and vanillin was stored at 25C?. Gamma irradiation diminished and storage time increased microbial growth. A synergistic effect between both variables on microbial growth was observed. Storage time decreased pH and color of purees. Sorbate content decreased with storage time and gamma irradiation. Mathematical models of microbial growth generated by the factorial design allowed estimating that a puree absorbing 1.63?kGy would have a shelf-life of 4 days. In order to improve this time, some changes in the applied hurdles were assayed. These included a thermal treatment before irradiation, a reduction of irradiation dose to 0.75?kGy and a decrease in storage temperature at 20C?. As a result, the shelf-life of purees increased to 28 days. PMID:23733817

  1. Statistical characteristics of lifetime distribution based on defect clustering for time-dependent dielectric breakdown in middle- and back-end-of-line

    NASA Astrophysics Data System (ADS)

    Yokogawa, Shinji

    2015-05-01

    The statistical characteristics of the lifetime distribution based on defect clustering were investigated for middle- and back-end-of-line time-dependent dielectric breakdown. The statistical precision of lifetime estimation was investigated. The maximum likelihood estimators of distribution parameters and their variations were developed by using asymptotic theory. The calculated asymptotic variation coefficient indicates that larger numbers of data are required to maintain the statistical precision of lifetime estimation for highly clustering conditions. However, the censoring of the test time to eliminate the tail of the lifetime distribution has a low impact on the asymptotic variation coefficient of the lifetime. These results provide valuable information for the experimental design of lifetime testing.

  2. Comprehensive analysis of 61 characteristic constituents from Siraitiae fructus using ultrahigh-pressure liquid chromatography with time-of-flight mass spectrometry.

    PubMed

    Zhou, Guisheng; Wang, Mengyue; Li, Yang; Xu, Renjie; Li, Xiaobo

    2016-06-01

    A systematic method was established for the qualitative and quantitative analysis of characteristic components such as triterpenoids and flavonols in Siraitiae fructus, a famous antidiabetic traditional Chinese medicine (TCM). For qualitative analysis, 61 characteristic components were identified using the ultra-high performance liquid chromatography coupled with photo-diode array and quadrupole/time-of-flight mass spectrometry (UPLC-PDA-QTOF-MS/MS) based on a multiple product ions filtering (mPIF) strategy, of which 22 compounds were characterized for the first time from Siraitiae fructus. For quantitative detection, a relative quantitation assay using an extract ion chromatogram (EIC) of the full scan MS experiment was validated and employed to assess the quantity of the 61 identified compounds in 40 batches Siraitiae fructus samples from different sources. Additionally, the principal component analysis (PCA) indicated that 40 samples could be clustered into four groups and the cultivated variety was an important factor for sample classification. The methods used in present study might be also valuable for simultaneous investigation of multiple components from Siraitiae fructus for the purpose of holistic quality control, phytochemistry and metabolic studies. PMID:26994551

  3. Influences of intrusion signal's characteristics on detection performances of the distributed sensor based on phase-sensitive optical time domain reflectometer

    NASA Astrophysics Data System (ADS)

    Zhan, Yage; Wang, Kun; Yu, Qiao; Wu, Hua; Kong, Yong

    2015-01-01

    Phase-sensitive optical time domain reflectometer (Φ-OTDR) has been a research hotspot in recent years. For Φ-OTDR, the Rayleigh backscattering light is monitored with a photodetector, and the plotted trace is a curve of the returned optical power versus time. The time is proportional to the distance from the location along the sensing fiber to the optical pulses' incident end. The trace presents the form of speckle-like profile owing to the coherent addition of the amplitudes of the light backscattered from different locations of the fiber. Based on this, the influences of the intrusion signal's characteristics (occurrence location and phase variation) on the detection performances of the distributed sensor based on Φ-OTDR are investigated theoretically and demonstrated experimentally, especially on signal-to-noise ratio (SNR), missing report, and location accuracy. Results show that if intrusions occur at locations corresponding to the curve's peak or subpeak and when its phase variation is (2k+1)π(k=1,2,3⋯), SNR will be the maximum. If intrusions occur at locations corresponding to the curve's troughs, a missing report will occur no matter what value is taken by the phase variation of the intrusion signal. On the other hand, experimental results show most missing reports can be uncovered by using a frequency tunable laser and/or optical pulses with an alternative repetition frequency.

  4. Real-time monitoring of cell apoptosis and drug screening using fluorescent light-up probe with aggregation-induced emission characteristics.

    PubMed

    Shi, Haibin; Kwok, Ryan T K; Liu, Jianzhao; Xing, Bengang; Tang, Ben Zhong; Liu, Bin

    2012-10-31

    Real-time monitoring of cell apoptosis could provide valuable insights into early detection of therapy efficiency and evaluation of disease progression. In this work, we designed and synthesized a new live-cell-permeable, fluorescent light-up probe for real-time cell apoptosis imaging. The probe is comprised of a hydrophilic caspase-specific Asp-Glu-Val-Asp (DEVD) peptide and a hydrophobic tetraphenylethene (TPE) unit, a typical fluorogen with aggregation-induced emission characteristics. In aqueous solution, the probe is almost nonfluorescent but displays significant fluorescence enhancement in response to caspase-3/-7, which are activated in the apoptotic process and able to cleave the DEVD moieties. This fluorescence "turn-on" response is ascribed to aggregation of cleaved hydrophobic TPE residues, which restricts the intramolecular rotations of TPE phenyl rings and populates the radiative decay channels. The light-up nature of the probe allows real-time monitoring of caspase-3/-7 activities both in solutions and in living cells with a high signal-to-noise ratio. The probe provides a new opportunity to screen enzyme inhibitors and evaluate the apoptosis-associated drug efficacy. PMID:23043485

  5. Long-term timing and glitch characteristics of anomalous X-ray pulsar 1RXS J170849.0–400910

    SciTech Connect

    Muş, Sinem Şaşmaz; Göğüş, Ersin

    2013-12-01

    We present the results of our detailed timing studies of an anomalous X-ray pulsar, 1RXS J170849.0–400910, using Rossi X-ray Timing Explorer (RXTE) observations spanning over ∼6 yr from 2005 until the end of the RXTE mission. We constructed the long-term spin characteristics of the source and investigated the time and energy dependence of the pulse profile and pulsed count rates. We find that the pulse profile and pulsed count rates in the 2-10 keV band do not show any significant variations in ∼6 yr. 1RXS J170849.0–400910 has been the most frequently glitching anomalous X-ray pulsar: three spin-up glitches and three candidate glitches were observed prior to 2005. Our extensive search for glitches later in the timeline resulted in no unambiguous glitches, though we identified two glitch candidates (with Δν/ν ∼ 10{sup –6}) in two data gaps: a strong candidate around MJD 55532 and another one around MJD 54819, which is slightly less robust. We discuss our results in the context of pulsar glitch models and expectancy of glitches within the vortex unpinning model.

  6. Evaluation of the effect of CaCl2 and alginate concentrations and hardening time on the characteristics of Lactobacillus acidophilus loaded alginate beads using response surface analysis

    PubMed Central

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    Purpose: This article describes preparation and characterization of beads of alginate containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Methods: Fourteen formulations using different alginate (ALG) and CaCl2 concentrations as well as hardening times were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology, encapsulation efficiency and bacterial viabilities in acid (pH 1.8, 2 hours) condition. Results: The results showed that spherical beads with narrow size distribution ranging from 1.32±0.04 to 1.70±0.07 mm were achieved with encapsulation efficiency higher than 98%. Surface response analysis revealed that alginate concentration was the important factor for the size, shape and encapsulation efficiency of prepared beads. Furthermore, survived bacteria after acid exposure in all prepared beads (63-83%) were significantly higher than those of untreated cells (39%) and enhanced by increasing alginate concentration. Surface response analysis revealed that the effect of all three factors of alginate and CaCl2 concentrations as well as hardening times were significant in acid viability, however alginate concentration played the most important role according to its regression coefficient. Conclusion: Among alginate and CaCl2 concentrations as well as hardening times, alginate concentration was the most variable in the characteristics of Alginate beads. PMID:24312773

  7. [Effects of cooking and steep time of nixtamalized corn grain (sea mayz L.) on the physicochemical, rheological, structural and textural characteristics of grain, mass and tortillas].

    PubMed

    Arámbula Villa, G; Barrón Avila, L; González Hernández, J; Moreno Martínez, E; Luna Bárcenas, G

    2001-06-01

    The corn tortilla is elaborated using corn grain masa processed by the traditional nixtamalization method, which consists of two steps: cooking and steeping. In these steps the physicochemical and structural properties are strongly affected, resulting in changes in the textural characteristics of the tortilla produced. In this work the effects of cooking and steeping time on the moisture content, amylographic profiles, crystallinity, weigh loss from masa to tortilla, starch damage, rollability, elasticity and cutting force for grain, masa and corn tortillas, were evaluated. The milling of the nixtamalized grain and the cooking of tortilla conditions were the same in all treatments. All tortillas samples showed a good rollability. The results show that the moisture content of corn grain was increased up to 42 g/100 g during the total cooking time (45 min), and it further increased to 52-53 g/100 g after when the cooked grain was steeped for 4 h. All evaluated parameters showed high correlation coefficients with the texture properties of tortillas. The starch damage was the variable with the best correlation among all evaluated parameters. The correlation coefficients between starch damage and moisture content, weigh loss and maximum viscosity for corn grain, masa and tortillas were larger than 0.92 (p < 0.01). The best tortillas were produced using nixtamal with the follow characteristics: moisture content of nixtamal, 42-44 g/100 g and tortilla, 43-44 g/100 g; adhesiveness of masa, 30-50 g; maximum viscosity of nixtamal, 860-880 cp and tortilla 490-510 cp; starch damage of nixtamal, 14 g/100 g and tortilla, 35-37 g/100 g, and weigh loss of tortilla during cooking, 16 g/100 g. PMID:11678051

  8. Mechanical characteristics of ultra-long horizontal nanocantilevers grown by real-time feedback control on focused-ion-beam chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Guo, Dengji; Warisawa, Shin'ichi; Ishihara, Sunao; Kometani, Reo

    2015-12-01

    Focused-ion-beam chemical vapour deposition (FIB-CVD) has been repeatedly proved to be a useful tool for the growth of three-dimensional (3D) micro- and nano-structures. The strategy of real-time feedback control on FIB-CVD was previously proposed and experimentally demonstrated to be effective for growing ultra-long horizontal nanocantilevers. To fabricate various nanoelectromechanical systems that consist of such types of nanocantilever structures, the mechanical characteristics of ultra-long horizontal nanocantilevers should be investigated. In this study, nanocantilevers with an overhang length of up to 35 μm were grown by using a 30 kV Ga+ FIB, a beam current of 0.50 pA and phenanthrene (C14H10) as the gas source to deposit a diamond-like carbon structure. The Young’s modulus of each nanocantilever was measured by bending the nanocantilever with a nanopillar whose Young’s modulus was known. The average density of each nanocantilever was calculated from the Young’s modulus and the measured resonant frequency. We found that the mechanical characteristics of each nanocantilever depended on the length of the nanocantilever if the strategy of real-time feedback control was applied in fabrication. The Young’s moduli and the averaged densities of the nanocantilevers with a length of 11 to 34 μm were found to be 86 to 254 GPa and 1950 to 5750 kg m-3, respectively. With the increase of the overhang length, the Young’s modulus and the average density were found to gradually increase.

  9. Characteristics of recent dust storms over the Indian region using real time multi-satellite observations from the direct broadcast receiving system at IMD

    NASA Astrophysics Data System (ADS)

    Mitra, A. K.; Sharma, A. K.; Soni, V. K.; Kundu, P. K.

    2013-04-01

    In this study, observations from microwave satellites, visible and infrared instruments have been analyzed to detect dust storm over north and north-west part of India during 18-23 March 2012. This study investigated the approach to utilize the multi satellite data of Moderate Resolution Imaging Spectroradiometer (MODIS) on-board the Terra and Aqua satellite and the Advanced Microwave Sounding Unit (AMSU) on-board NOAA satellite to study the characteristics of dust storms from real time direct broadcast (DB) receiving system installed at three places of India Meteorological Department (IMD). The dust storm detection is based on the infrared brightness temperature (BT) difference between channels at 11 and 12 ?m and polarized BT difference between two channels of 89 and 23.8 GHz. It is found that the significant differences between the BT of channel 89 and 23.8 can be used as a discriminator of identifying dust storm. The Total Ozone Mapping Spectroradiometer (TOMS) Aerosol Index (AI) and AMSU-A 23 GHz channel BT from NOAA satellite over the north and north-west part of India have also been analyzed. The result indicated the characteristic behavior between BT and AI during the different phases of the dust storm. Finally, the occurrence of dust outbreaks has also been validated with sky radiometer of IMD, which confirms the presence of a dust storm over the Indian region. Further, the findings of the study and its approaches apply to the other dust storm cases which occurred during the months of April and June 2012. The integrated approach suggested the potential to use high resolution data of microwave as well as thermal-infrared using multi-satellite observations from real time direct broadcast system for the detection of severe, moderate or weak dust storms very well. The approach is found to be promising for operational application.

  10. In-silico experiments on characteristic time scale at a shear-free gas-liquid interface in fully developed turbulence

    NASA Astrophysics Data System (ADS)

    Nagaosa, Ryuichi; Handler, Robert A.

    2011-12-01

    The purpose of this study is to model scalar transfer mechanisms in a fully developed turbulence for accurate predictions of the turbulent scalar flux across a shear-free gas-liquid interface. The concept of the surface-renewal approximation (Dankwerts, 1951) is introduced in this study to establish the predictive models for the interfacial scalar flux. Turbulent flow realizations obtained by a direct numerical simulation technique are employed to prepare details of three-dimensional information on turbulence in the region very close to the interface. Two characteristic time scales at the interface have been examined for exact prediction of the scalar transfer flux. One is the time scale which is reciprocal of the root-mean-square surface divergence, Tγ = langleγγrangle-1/2, where γ is the surface divergence. The other time scale to be examined is TS = Λ/V, where Λ is the zero-correlation length of the surface divergence as the interfacial length scale, and V is the root-mean-square velocity fluctuation in the streamwise direction as the interfacial velocity scale. The results of this study suggests that Tγ is slightly unsatisfactory to correlate the turbulent scalar flux at the gas-liquid interface based on the surface-renewal approximation. It is also found that the proportionality constant appear to be 0.19, which is different with that observed in the laboratory experiments, 0.34 (Komori, Murakami, & Ueda, 1989). It is concluded that the time scale, Tγ, is considered a different kind of the time scale observed in the laboratory experiments. On the other hand, the present in-silico experiments indicate that Ts predicts the turbulent scalar flux based on the surface-renewal approximation in a satisfactory manner. It is also elucidated that the proportionality constant for Ts is approximately 0.36, which is very close to that found by the laboratory experiments. This fact shows that the time scale Ts appears to be essentially the same as the time scale the laboratory experiments observed.

  11. Time scale dependence of the center of pressure entropy: What characteristics of the neuromuscular postural control system influence stabilographic entropic half-life?

    PubMed

    Federolf, Peter; Zandiyeh, Payam; von Tscharner, Vinzenz

    2015-12-01

    The center of pressure (COP) movement in studies of postural control reveals a highly regular structure (low entropy) over short time periods and a highly irregular structure over large time scales (high entropy). Entropic half-life (EnHL) is a novel measure that quantifies the time over which short-term temporal correlations in a time series deteriorate to an uncorrelated, random structure. The current study suggested and tested three hypotheses about how characteristics of the neuromuscular postural control system may affect stabilometric EnHL: (H1) control system activity hypothesis: EnHL decreases with increased frequency of control system interventions adjusting COP motion; (H2) abundance of states hypothesis: EnHL decreases with increased number of mechanically equivalent states available to the postural system; and (H3) neurologic process hierarchy hypothesis: EnHL increases if postural control functions shift from the spinal level to the motor cortex. Thirty healthy participants performed quiet stance tests for 90 s in 18 different conditions: stance (bipedal, one-legged, and tandem); footwear (bare foot, regular sports shoe, and rocker sole shoes); and simultaneous cognitive task (two-back working memory task, no challenge). A four-way repeated-measures ANOVA revealed significant changes in EnHL for the different stance positions and for different movement directions (medio-lateral, anterior-posterior). These changes support H1 and H2. Significant differences were also found between rocker sole shoes and normal or barefoot standing, which supports H3. This study contributes to the understanding of how and why EnHL is a useful measure to monitor neuromuscular control of balance. PMID:26303025

  12. A statistically significant long term characteristic time-scale of test size variation of Calcareous Trochospiral Benthic Foraminifera (CTBF) during the past 120 m.y.

    NASA Astrophysics Data System (ADS)

    Tiwari, R. K.; Rao, K. N. N.

    2003-03-01

    Geo-marine records are faithful recorders of the earth's evolutionary history and hence are most suitable for identifying long-term cyclic patterns. Although a remarkable synchronism among Calcareous Trochospiral Benthic Foraminifera (CTBF) test size variation, ocean productivity, dissolved oxygen and global climate exists, global ``geospectroscopy'' is essential for understanding the wider ramification of significant physical linkages of the various terrestrial and extra-terrestrial processes. Earlier claims of a quasi-periodicity of 26-36 m.y. in various geo-bio-ocean-atmospheric records sparked a major controversy. Here, we examine spectral characteristics of the latest available time series representing fluctuations in test size of CTBF for the past 120 m.y. using the Multi-Taper Method (MTM) and Maximum Entropy Method (MEM) of spectral analyses. The analyses of test size variations of CTBF time series reveal, hitherto unidentified, a statistically significant and stable harmonic component of 35 +/- 5 m.y. against a robust ``red background noise''. Further, wavelet spectral analysis of this record exhibits a strong stationary power in the above frequency band suggesting temporal persistence of spectral peak through the entire evolutionary period. This finding renders credible support to the concept of cyclic geo-marine processes and will provide stimulus for further quantitative research into the coupling of marine geo-bio-chemical cycles.

  13. Impact of model resolution on sea-level variability characteristics at various space and time scales: insights from four DRAKKAR global simulations and the AVISO altimeter data

    NASA Astrophysics Data System (ADS)

    Penduff, T.; Juza, M.; Brodeau, L.; Smith, G. C.; Barnier, B.; Molines, J.-M.; Treguier, A.-M.

    2009-07-01

    Four global ocean/sea-ice simulations driven by the same realistic 46-year daily atmospheric forcing were performed within the DRAKKAR project at 2, 1, ½ and ¼ resolutions. Model sea-level anomalies are collocated over the period 1993-2004 onto the AVISO SLA dataset. These five collocated SLA datasets are then filtered and quantitatively compared over various time and space scales regarding three characteristics: SLA standard deviations, spatial correlations between SLA variability maps, and temporal correlations between observed and simulated band-passed filtered local SLA timeseries. Beyond the 2-1 transition whose benefits are quite moderate, further increases in resolution and associated changes in subgrid scale parameterizations simultaneously induce (i) strong increases in SLA standard deviations, (ii) strong improvements in the spatial distribution of SLA variability, and (iii) slight decreases in temporal correlations between observed and simulation SLA timeseries. These 3 effects are not only clear on mesoscale (14-180 days) and quasi-annual (5-18 months) fluctuations, but also on the slower (interannual), large-scale variability ultimately involved in ocean-atmosphere coupled processes. Most SLA characteristics are monotonically affected by successive resolution increases, but irregularly and with a strong dependance on frequency and latitude. Benefits of enhanced resolution are maximum in the ½-¼ transition, in the 14-180 day range, and within eddy-active mid- and high-latitude regions. They are particularly clear in the Southern Ocean where mesoscale eddies probably sustain a substantial intrinsic interannual variability.

  14. Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations

    SciTech Connect

    Das, Anuradha; Das, Suman; Biswas, Ranjit

    2015-01-21

    Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH{sub 3}CONH{sub 2}) and urea (NH{sub 2}CONH{sub 2}) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH{sub 3}CONH{sub 2} + (1 − f)NH{sub 2}CONH{sub 2}] have been studied in a temperature range of 328-353 K which is ∼120-145 K above the measured glass transition temperatures (∼207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (∼70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α{sub 2}) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.

  15. Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): time-resolved fluorescence measurements and all-atom molecular dynamics simulations.

    PubMed

    Das, Anuradha; Das, Suman; Biswas, Ranjit

    2015-01-21

    Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ∼120-145 K above the measured glass transition temperatures (∼207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (∼70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α2) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems. PMID:25612718

  16. Use of Self-Matching to Control for Stable Patient Characteristics While Addressing Time-Varying Confounding on Treatment Effect: A Case Study of Older Intensive Care Patients

    PubMed Central

    Han, Ling; Pisani, M.A.; Araujo, K.L.B.; Allore, Heather G.

    2016-01-01

    Exposure-crossover design offers a non-experimental option to control for stable baseline confounding through self-matching while examining causal effect of an exposure on an acute outcome. This study extends this approach to longitudinal data with repeated measures of exposure and outcome using data from a cohort of 340 older medical patients in an intensive care unit (ICU). The analytic sample included 92 patients who received ≥1 dose of haloperidol, an antipsychotic medication often used for patients with delirium. Exposure-crossover design was implemented by sampling the 3-day time segments prior (Induction) and posterior (Subsequent) to each treatment episode of receiving haloperidol. In the full cohort, there was a trend of increasing delirium severity scores (Mean±SD: 4.4±1.7) over the course of the ICU stay. After exposure-crossover sampling, the delirium severity score decreased from the Induction (4.9) to the Subsequent (4.1) intervals, with the treatment episode falling in-between (4.5). Based on a GEE Poisson model accounting for self-matching and within-subject correlation, the unadjusted mean delirium severity scores was −0.55 (95% CI: −1.10, −0.01) points lower for the Subsequent than the Induction intervals. The association diminished by 32% (−0.38, 95%CI: −0.99, 0.24) after adjusting only for ICU confounding, while being slightly increased by 7% (−0.60, 95%CI: −1.15, −0.04) when adjusting only for baseline characteristics. These results suggest that longitudinal exposure-crossover design is feasible and capable of partially removing stable baseline confounding through self-matching. Loss of power due to eliminating treatment-irrelevant person-time and uncertainty around allocating person-time to comparison intervals remain methodological challenges.

  17. Mapping crop based on phenological characteristics using time-series NDVI of operational land imager data in Tadla irrigated perimeter, Morocco

    NASA Astrophysics Data System (ADS)

    Ouzemou, Jamal-eddine; El Harti, Abderrazak; EL Moujahid, Ali; Bouch, Naima; El Ouazzani, Rabii; Lhissou, Rachid; Bachaoui, El Mostafa

    2015-10-01

    Morocco is a primarily arid to semi-arid country. These climatic conditions make irrigation an imperative and inevitable technique. Especially, agriculture has a paramount importance for the national economy. Retrieving of crops and their location as well as their spatial extent is useful information for agricultural planning and better management of irrigation water resource. Remote sensing technology was often used in management and agricultural research. Indeed, it's allows crops extraction and mapping based on phenological characteristics, as well as yield estimation. The study area of this work is the Tadla irrigated perimeter which is characterized by heterogeneous areas and extremely small size fields. Our principal objectives are: (1) the delimitation of the major crops for a good water management, (2) the insulation of sugar beet parcels for modeling its yields. To achieve the traced goals, we have used Landsat-8 OLI (Operational Land Imager) data pan-sharpened to 15 m. Spectral Angle Mapper (SAM) and Support Vector Machine (SVM) classifications were applied to the Normalized Difference Vegetation Index (NDVI) time-series of 10 periods. Classifications were calculated for a site of more than 124000 ha. This site was divided into two parts: the first part for selecting, training datasets and the second one for validating the classification results. The SVM and SAM methods classified the principal crops with overall accuracies of 85.27% and 57.17% respectively, and kappa coefficient of 80% and 43% respectively. The study showed the potential of using time-series OLI NDVI data for mapping different crops in irrigated, heterogeneous and undersized parcels in arid and semi-arid environment.

  18. Time Trends in Epidemiologic Characteristics and Imaging Features of Lung Adenocarcinoma: A Population Study of 21,113 Cases in China

    PubMed Central

    Zhang, Li; Li, Meng; Wu, Ning; Chen, Yuheng

    2015-01-01

    Objectives This study aims to describe time trends of epidemiologic characteristics and imaging features over 14 years among histologically confirmed lung adenocarcinoma (ADC) in China and to discuss the possible reasons for these changes. Materials and Methods Data of 21,113 pathologically confirmed lung cancer patients from January 1999 to December 2012 were analyzed retrospectively. Preoperative high-resolution computer tomography (HRCT) images were available and reviewed in 5,439 lung ADC patients since 2005. Time trends of the ADC proportion of lung cancer cases, gender distribution, age at diagnosis, the proportion of early-stage ADC and imaging features were investigated. Results The proportion of ADC increased during the 14 years (P = 0.000). The ratio of female to male ADC cases was higher than both squamous cell carcinoma (SQCC) and total lung cancer cases (P = 0.000). The median age at diagnosis of ADC patients was younger than that of both SQCC and total lung cancer during the 14 years (P = 0.000). The proportion of age group 45–59 years increased in total lung cancer cases (P = 0.000). When stratified by lung cancer histopathologic subtypes, this trend was also observed in ADC (P = 0.001) and SQCC (P = 0.007). The proportion of early-stage cases of ADC increased from 2008 to 2012 (P < 0.001). The proportion of subsolid nodules (SSN) in ADC increased (P = 0.001) from 2005 to 2012. Conclusion The data suggests that the proportion of ADC increased from 1999 to 2012 especially in middle-aged, female patients; early-stage ADC and SSN on HRCT images gradually increased, which may have been caused by a change in smoking habits and increased application of HRCT. PMID:26317971

  19. Time-resolved inorganic chemical composition of fine aerosol and associated precursor gases over an urban environment in western India: Gas-aerosol equilibrium characteristics

    NASA Astrophysics Data System (ADS)

    Sudheer, A. K.; Rengarajan, R.

    2015-05-01

    Inorganic ionic constituents (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3- and SO42-) of PM2.5 and associated trace gases (NH3, HNO3 and HCl) were measured simultaneously by Ambient Ion Monitor - Ion Chromatograph (AIM-IC) system with a time resolution of one hour at an urban location in semi-arid region of western India during summer and winter. The average NH3, HNO3 and HCl concentrations were 11.6 ± 5.0, 2.9 ± 0.8 and 0.15 μg m-3, respectively, during winter. During summer, NH3 and HNO3 concentrations were of similar magnitude, whereas HCl concentration was less than ∼0.03 μg m-3. NH3 concentration exhibited a distinct diurnal variation during both seasons. However, HNO3 did not show a specific diurnal trend during the observation period in both seasons. The data obtained were used to study gas-aerosol equilibrium characteristics using a thermodynamic equilibrium model, ISORROPIA II. The results suggest that NH3 exists in equilibrium between measured fine-mode particle and gas phase with a systematic bias of ∼14%, whereas HCl and HNO3 deviate significantly from the modelled data. These observations have implications on thermodynamic equilibrium assumptions used for estimating various aerosol parameters such as liquid water content, pH, etc., thus causing significant bias in chemical transport model results over the study region.

  20. When holding your horses meets the deer in the headlights: time-frequency characteristics of global and selective stopping under conditions of proactive and reactive control

    PubMed Central

    Lavallee, Christina F.; Meemken, Marie T.; Herrmann, Christoph S.; Huster, Rene J.

    2014-01-01

    The ability to inhibit unwanted thoughts or actions is crucial for successful functioning in daily life; however, this ability is often impaired in a number of psychiatric disorders. Despite the relevance of inhibition in everyday situations, current models of inhibition are rather simplistic and provide little generalizability especially in the face of clinical disorders. Thus, given the importance of inhibition for proper cognitive functioning, the need for a paradigm, which incorporates factors that will subsequently improve the current model for understanding inhibition, is of high demand. A popular paradigm used to assess motor inhibition, the stop-signal paradigm, can be modified to further advance the current conceptual model of inhibitory control and thus provide a basis for better understanding different facets of inhibition. Namely, in this study, we have developed a novel version of the stop-signal task to assess how preparation (that is, whether reactive or proactive) and selectivity of the stopping behavior effect well-known time-frequency characteristics associated with successful inhibition and concomitant behavioral measures. With this innovative paradigm, we demonstrate that the selective nature of the stopping task modulates theta and motoric beta activity and we further provide the first account of delta activity as an electrophysiological feature sensitive to both manipulations of selectivity and preparatory control. PMID:25540615

  1. A Neurophysiological Approach for Evaluating Noise-Induced Sleep Disturbance: Calculating the Time Constant of the Dynamic Characteristics in the Brainstem

    PubMed Central

    Tagusari, Junta; Matsui, Toshihito

    2016-01-01

    Chronic sleep disturbance induced by traffic noise is considered to cause environmental sleep disorder, which increases the risk of cardiovascular disease, stroke, diabetes and other stress-related diseases. However, noise indices for the evaluation of sleep disturbance are not based on the neurophysiological process of awakening regulated by the brainstem. In this study, through the neurophysiological approach, we attempted (1) to investigate the thresholds of awakening due to external stimuli in the brainstem; (2) to evaluate the dynamic characteristics in the brainstem and (3) to verify the validity of existing noise indices. Using the mathematical Phillips–Robinson model, we obtained thresholds of awakening in the brainstem for different durations of external stimuli. The analysis revealed that the brainstem seemed insensitive to short stimuli and that the response to external stimuli in the brainstem could be approximated by a first-order lag system with a time constant of 10–100 s. These results suggest that the brainstem did not integrate sound energy as external stimuli, but neuroelectrical signals from auditory nerve. To understand the awakening risk accumulated in the brainstem, we introduced a new concept of “awakening potential” instead of sound energy. PMID:27023587

  2. A Neurophysiological Approach for Evaluating Noise-Induced Sleep Disturbance: Calculating the Time Constant of the Dynamic Characteristics in the Brainstem.

    PubMed

    Tagusari, Junta; Matsui, Toshihito

    2016-01-01

    Chronic sleep disturbance induced by traffic noise is considered to cause environmental sleep disorder, which increases the risk of cardiovascular disease, stroke, diabetes and other stress-related diseases. However, noise indices for the evaluation of sleep disturbance are not based on the neurophysiological process of awakening regulated by the brainstem. In this study, through the neurophysiological approach, we attempted (1) to investigate the thresholds of awakening due to external stimuli in the brainstem; (2) to evaluate the dynamic characteristics in the brainstem and (3) to verify the validity of existing noise indices. Using the mathematical Phillips-Robinson model, we obtained thresholds of awakening in the brainstem for different durations of external stimuli. The analysis revealed that the brainstem seemed insensitive to short stimuli and that the response to external stimuli in the brainstem could be approximated by a first-order lag system with a time constant of 10-100 s. These results suggest that the brainstem did not integrate sound energy as external stimuli, but neuroelectrical signals from auditory nerve. To understand the awakening risk accumulated in the brainstem, we introduced a new concept of "awakening potential" instead of sound energy. PMID:27023587

  3. The relationship between biological cognitive and psychosocial characteristics of parents and the weight of infant at the time of birth in Isfahan

    PubMed Central

    Talebian, Mohammad Hassan; Afrooz, Gholam Ali; Hooman, Heidar Ali; Aghaei, Asghar

    2013-01-01

    Introduction: The present study was connected in order to evaluate the relationship between biological, cognitive and psychosocial characteristics of mothers and the weight of infant at the time of birth. Materials and Methods: In order to conduct this research a sample of 910 women among recently delivered mothers of Isfahan province in 2009 were selected. From stratified sampling and cluster sampling according to the percentage of population in each of the cities of Isfahan Province was used. The data was gathered with a questionnaire prepared by the researcher in order to evaluate the biological cognitive and psychosocial characteristics of mothers, in addition to the Enrich marital satisfaction test. After collecting data, the analysis of the data was done with SPSS software in two categories of descriptive and inferential statistics by using logistic regression model. Results: The results showed that the prevalence of low weight infants was 9.5 percent and 38.7 percent of pregnancies was unwanted. Twenty-nine percent of mothers had marital dissatisfaction. 15/6 percent of pregnancies were below 20 years old and 22 percent was above of 35 years old. 38.9 percent of mothers were exposed to cigarette smoke. The average of weight gain during pregnancies was 9 kilograms. Thirty three percent of mothers had high blood pressure during pregnancy, 26.7 percent had history of abortion and 31.9 percent had history of bleeding. 23/1percent of women was employed during pregnancy, 19.8 percent gave twin birth and 21/1 percent of parents were relative of each other, 29.7 percent of deliveries were done in cesarean way. Conclusion: The results of this study showed that severe marital dissatisfaction, abnormal blood pressure during pregnancy, being employed during pregnancy, weight gain less than 5 Kg during pregnancy, pregnancy below the age of 20 can meaning fully increase the possibility of low birth weight in infant (α=0.05). The results were consisting with the previous findings and indicated that some of the applicable benefits of this research can be recording of information about each delivery in the whole country with holding training workshops of before and during pregnancy skills by welfare organization. PMID:24251279

  4. Determination of time-of-travel, dispersion characteristics, and oxygen reaeration coefficients during low streamflows--Lower Tacony/Frankford Creek, Philadelphia, Pennsylvania

    USGS Publications Warehouse

    Senior, Lisa A.; Gyves, Matthew C.

    2010-01-01

    Time-of-travel, dispersion characteristics, and oxygen reaeration coefficients were determined by use of dye and gas tracing for a 2-mile reach of Tacony/Frankford Creek in Philadelphia, southeastern Pennsylvania. The reach frequently has concentrations of dissolved oxygen (DO) below the water-quality standard of 4 milligrams per liter during warm months. Several large combined sewer overflows (CSOs), including one of the largest in Philadelphia (former Wingohocking Creek), discharge to the study reach in this urbanized watershed, affecting water quality and the timing and magnitude of storm peaks. In addition, a dam that commonly results in backwater conditions and reduced natural reaeration is present a few hundred feet from the end of the study reach. Time-of-travel and reaeration data were collected under base-flow conditions in August and September 2009 for three sub-reaches from Roosevelt Boulevard (U.S. Route 1) to Castor Avenue. Determination of traveltimes to the centroid of the dye cloud were needed for calculation of the reaeration coefficients. Results of the dye study in Tacony/Frankford Creek indicate that traveltimes were affected by the presence of man-made structures, such as the large scour hole and pool developed at the outfall of the T14 CSO and the dam, both of which reduce stream velocities. Mean stream velocities during the dye-tracer tests ranged from a maximum of 0.44 to 0.04 foot per second through a large pool. The dispersion efficiency of the stream was determined from relations between normalized unit concentrations to time to peak for use in water-quality modeling. Oxygen reaeration coefficients determined by a constant rate-injection method using propane as the tracer gas were as low as 0.04 unit per hour in a long pool affected by backwater conditions behind a dam. The highest reaeration coefficient was 2.29 units per hour for a steep-gradient reach with multiple winding channels through gravel deposits, just downstream of a large scour pool developed at the outlet of the T14 CSO. Reaeration coefficients determined from the field tracer-gas method were compared to values calculated by two other methods, one that is based on theoretical equations using physical properties of the stream as variables and the other that is based on equations using the timing of measured daily maximum DO concentrations in the stream. Reaeration coefficients from the two alternate methods were most similar to values determined from the field tracer-gas method for the upstream portion of the study reach, characterized by free-flowing riffle and pools. Values of reaeration coefficients determined by the tracer-gas method were 2 to 10 times higher than values determined by 2 alternate methods for most subreaches hydraulically affected by man-made structures. In addition to the tracer gas, propane, the gas analysis also included methane, ethane, and ethene, of which only methane was measured in concentrations above a few micrograms per liter. Methane, thought to occur naturally or because of ongoing processes in the stream, was measured in concentrations ranging from 6.6 to 78 micrograms per liter; the concentrations were greatest in sub-reaches dominated by pools.

  5. Lifetime Characteristics of Evening-Preference and Irregular Bed-Rise Time Are Associated With Lifetime Seasonal Variation of Mood and Behavior: Comparison Between Individuals With Bipolar Disorder and Healthy Controls.

    PubMed

    Baek, Ji Hyun; Kim, Ji Sun; Kim, Mi Jin; Ryu, Seunghyung; Lee, Kounseok; Ha, Kyooseob; Hong, Kyung Sue

    2016-01-01

    Sleep-wake cycle disruption and seasonal variation in mood and behavior have been associated with mood disorders. This study aimed to investigate the lifetime characteristics of the sleep-wake cycle and its association with the lifetime characteristics of seasonality in individuals with bipolar disorder. Circadian preference, regularity of bed-rise time, and seasonality were evaluated on a lifetime basis using the Composite Scale of Morningness, the Sleep Timing Questionnaire, and the Seasonal Pattern Assessment Questionnaire in clinically stable individuals with bipolar I/II disorders (n = 103/97) and healthy controls (n = 270). Bipolar groups were more likely to have evening preference and irregular bed-rise time. These characteristics were interrelated and, particularly, more prevalent in bipolar II disorder. Seasonality, which was also more prevalent in the bipolar groups, was associated with evening preference and irregularity of the weekday bed-rise time. PMID:25384190

  6. Identification of Extreme Events Under Climate Change Conditions Over Europe and The Northwest-atlantic Region: Spatial Patterns and Time Series Characteristics

    NASA Astrophysics Data System (ADS)

    Leckebusch, G.; Ulbrich, U.; Speth, P.

    In the context of climate change and the resulting possible impacts on socio-economic conditions for human activities it seems that due to a changed occurrence of extreme events more severe consequences have to be expected than from changes in the mean climate. These extreme events like floods, excessive heats and droughts or windstorms possess impacts on human social and economic life in different categories such as forestry, agriculture, energy use, tourism and the reinsurance business. Reinsurances are affected by nearly 70% of all insured damages over Europe in the case of wind- storms. Especially the December 1999 French windstorms caused damages about 10 billion. A new EU-founded project (MICE = Modelling the Impact of Climate Ex- tremes) will focus on these impacts caused by changed occurrences of extreme events over Europe. Based upon the output of general circulation models as well as regional climate models, investigations are carried out with regard to time series characteristics as well as the spatial patterns of extremes under climate changed conditions. After the definition of specific thresholds for climate extremes, in this talk we will focus on the results of the analysis for the different data sets (HadCM3 and CGCMII GCM's and RCM's, re-analyses, observations) with regard to windstorm events. At first the results of model outputs are validated against re-analyses and observations. Especially a comparison of the stormtrack (2.5 to 8 day bandpass filtered 500 hPa geopotential height), cyclone track, cyclone frequency and intensity is presented. Highly relevant to damages is the extreme wind near the ground level, so the 10 m wind speed will be investigated additionally. of special interest to possible impacts is the changed spatial occurrence of windspeed maxima under 2xCO2-induced climate change.

  7. Step-changes in the physical, chemical and biological characteristics of the Gulf of Maine, as documented by the GNATS time series

    USGS Publications Warehouse

    Balch, William M.; Drapeau, D.T.; Bowler, B.C.; Huntington, Thomas G.

    2012-01-01

    We identify step-changes in the physical, chemical and biological characteristics of the Gulf of Maine (GoM) using the Gulf of Maine North Atlantic Time Series (GNATS), a series of oceanographic measurements obtained between September 1998 and December 2010 along a transect in the GoM running from Portland, ME, to Yarmouth, NS. GNATS sampled a period of extremes in precipitation and river discharge (4 of the 8 wettest years of the last century occurred between 2005 and 2010). Coincident with increased precipitation, we observed the following shifts: (1) decreased salinity and density within the surface waters of the western GoM; (2) both reduced temperature and vertical temperature gradients in the upper 50 m; (3) increased colored dissolved organic matter (CDOM) concentrations and particle scattering in the western GoM; (4) increased concentrations of nitrate and phosphate across all but the eastern GoM; (5) increased silicate, particularly in the western GoM, with a sharp increase in the ratio of silicate to dissolved inorganic nitrogen; (6) sharply decreased carbon fixation by phytoplankton; (7) moderately decreased chlorophyll, particulate organic carbon (POC) and particulate inorganic carbon (PIC) in the central GoM and (8) decreased POC- and PIC-specific growth rates. Gulf-wide anomaly analyses suggest that (1) the surface density changes were predominantly driven by temperature, (2) dissolved nutrients, as well as POC/PON, varied in Redfield ratios and (3) anomalies for salinity, density, CDOM, particle backscattering and silicate were significantly correlated with river discharge. Precipitation and river discharge appear to be playing a critical role in controlling the long-term productivity of the Gulf of Maine by supplying CDOM and detrital material, which ultimately competes with phytoplankton for light absorption.

  8. Comparison of the physiological responses and time-motion characteristics of young soccer players in small-sided games: the effect of goalkeeper.

    PubMed

    Köklü, Yusuf; Sert, Özcan; Alemdaroğlu, Utku; Arslan, Yunus

    2015-04-01

    The purpose of this study was to investigate the effect of "with goalkeeper" (SSGwith) and "without goalkeeper" (SSGwithout) conditions on players' physiological responses and time-motion characteristics in small-sided games. Sixteen young soccer players (age: 16.5 ± 1.5 years; height: 175.5 ± 5.2 cm; body mass: 63.0 ± 6.9 kg; training experience: 6.3 ± 1.3 years) participated in 2 different 2-a-side, 3-a-side, and 4-a-side games: SSGwith and SSGwithout. The players underwent anthropometric measurements (height and body mass) followed by the Yo-Yo intermittent recovery test (level 1). Then they played 2-a-side, 3-a-side, and 4-a-side SSGwith and SSGwithout soccer-specific SSGs in random order at 2-day intervals. Heart rate (HR) responses and distance covered in different speed zones (walking [WLK, 0-6.9 km·h(-1)], low-intensity running [LIR, 7.0-12.9 km·h(-1)], moderate-intensity running [MIR, 13.0-17.9 km·h(-1)], and high-intensity running [HIR, >18 km·h(-1)]) were measured during the SSGs, whereas the rating of perceived exertion (RPE) and blood lactate (La) were determined at the end of the last bout of each SSG. During the SSGwithout players showed higher %HR, La, and RPE (p ≤ 0.05), greater distance covered in LIR, MIR, HIR, and total distance (p ≤ 0.05) compared with the SSGwith during the 2-a-side, 3-a-side, and 4-a-side games. The results of this study suggest that both SSGwith and SSGwithout could be used for the physiological adaptations required for soccer-specific aerobic endurance. However, if coaches want both higher physiological responses and greater distance covered in the intensity running zone from their teams, SSGwithout should be organized. In addition, this study also suggests that smaller format games (i.e., 2-a-side) may promote some anaerobic adaptations for youth soccer players. PMID:23942169

  9. SPATIO-TEMPORAL EVOLUTION AND TIME-STABLE CHARACTERISTICS OF SOIL MOISTURE WITHIN REMOTE SENSING FOOTPRINTS WITH VARYING SOIL, SLOPE, AND VEGETATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Air-borne passive microwave remote sensors measure soil moisture at the footprint scale, a scale of several hundred square meters or kilometers that encompasses different characteristic combinations of soil, topography, vegetation, and climate. Studies of within-footprint variability of soil moistur...

  10. Perception of goal proximity, latency and duration of action plans, and worry in relation to goal distance in time and personality characteristics.

    PubMed

    Halvari, H

    1991-06-01

    128 male high school students were tested for achievement motives, future-time orientation and perceived intrinsic instrumentality, and answered several questions related to future goals or tests at different distances in time. Success-oriented individuals and individuals with high future-time orientation perceived the goals as closer, planned to initiate preparations for the goals earlier, and planned to devote more time in the preparation than failure-oriented individuals and those with low future-time orientation. Interactions of motives and future-time orientation on the perception of goal proximity and planned time of initiating goal preparations did also emerge. Motives and future-time orientation affected the dependent variables most when the goals were at some distance in time (i.e., 1 yr. and 3 mo.), and the effects were minimized for the goal relatively close in time (i.e., 1 wk.). Individuals with high instrumentality report that they would start preparations earlier, devote more time to all goal preparations, and perceive more worry for the goal closest in time than individuals with low instrumentality. In addition, interactions of motives and instrumentality and of future-time orientation and instrumentality are presented. The results are interpreted and discussed in relation to the dynamics of action theory of Atkinson and Birch and other theories of achievement motivation. PMID:1891307

  11. A time dependent difference theory for sound propagation in ducts with flow. [characteristic of inlet and exhaust ducts of turbofan engines

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.

    1979-01-01

    A time dependent numerical solution of the linearized continuity and momentum equation was developed for sound propagation in a two dimensional straight hard or soft wall duct with a sheared mean flow. The time dependent governing acoustic difference equations and boundary conditions were developed along with a numerical determination of the maximum stable time increments. A harmonic noise source radiating into a quiescent duct was analyzed. This explicit iteration method then calculated stepwise in real time to obtain the transient as well as the steady state solution of the acoustic field. Example calculations were presented for sound propagation in hard and soft wall ducts, with no flow and plug flow. Although the problem with sheared flow was formulated and programmed, sample calculations were not examined. The time dependent finite difference analysis was found to be superior to the steady state finite difference and finite element techniques because of shorter solution times and the elimination of large matrix storage requirements.

  12. A Nonlinear Theory for Predicting the Effects of Unsteady Laminar, Turbulent, or Transitional Boundary Layers on the Attenuation of Shock Waves in a Shock Tube with Experimental Comparison

    NASA Technical Reports Server (NTRS)

    Trimpi, Robert L.; Cohen, Nathaniel B.

    1961-01-01

    The linearized attenuation theory of NACA Technical Note 3375 is modified in the following manner: (a) an unsteady compressible local skin-friction coefficient is employed rather than the equivalent steady-flow incompressible coefficient; (b) a nonlinear approach is used to permit application of the theory to large attenuations; and (c) transition effects are considered. Curves are presented for predicting attenuation for a shock pressure ratio up to 20 and a range of shock-tube Reynolds numbers. Comparison of theory and experimental data for shock-wave strengths between 1.5 and 10 over a wide range of Reynolds numbers shows good agreement with the nonlinear theory evaluated for a transition Reynolds number of 2.5 X 10(exp 5).

  13. Do socioeconomic characteristics modify the short term association between air pollution and mortality? Evidence from a zonal time series in Hamilton, Canada

    PubMed Central

    Jerrett, M; Burnett, R; Brook, J; Kanaroglou, P; Giovis, C; Finkelstein, N; Hutchison, B

    2004-01-01

    Study objective: To assess the short term association between air pollution and mortality in different zones of an industrial city. An intra-urban study design is used to test the hypothesis that socioeconomic characteristics modify the acute health effects of ambient air pollution exposure. Design: The City of Hamilton, Canada, was divided into five zones based on proximity to fixed site air pollution monitors. Within each zone, daily counts of non-trauma mortality and air pollution estimates were combined. Generalised linear models (GLMs) were used to test mortality associations with sulphur dioxide (SO2) and with particulate air pollution measured by the coefficient of haze (CoH). Main results: Increased mortality was associated with air pollution exposure in a citywide model and in intra-urban zones with lower socioeconomic characteristics. Low educational attainment and high manufacturing employment in the zones significantly and positively modified the acute mortality effects of air pollution exposure. Discussion: Three possible explanations are proposed for the observed effect modification by education and manufacturing: (1) those in manufacturing receive higher workplace exposures that combine with ambient exposures to produce larger health effects; (2) persons with lower education are less mobile and experience less exposure measurement error, which reduces bias toward the null; or (3) manufacturing and education proxy for many social variables representing material deprivation, and poor material conditions increase susceptibility to health risks from air pollution. PMID:14684724

  14. Production of nanocrystalline cellulose from an empty fruit bunches using sulfuric acid hydrolysis: Effect of reaction time on the molecular characteristics

    NASA Astrophysics Data System (ADS)

    Al-Dulaimi, Ahmed A.; R, Rohaizu; D, Wanrosli W.

    2015-06-01

    Nanocrystalline cellulose (NCC) was isolated from OPEFB pulp via sulfuric acid hydrolysis. The influence of reaction time to the molecular weight and surface charge of the NCC was investigated. Characterization of the product was carried out using zeta potential measurement and gel permeation chromatography test. Zeta potential measurement showed that the surface negative charge significantly increases with increasing reaction time. Gel permeation chromatography test indicates that molecular weight of NCC change variably with increasing of hydrolysis time. (Keywords: Nanocrystalline cellulose; acid hydrolysis; sulfate content; molecular weight)

  15. Marination with natural curing ingredients, storage time, and serving temperature effects on the sensory characteristics of forage-finished or commercially-sourced beef roasts.

    PubMed

    McMurtrie, K E; Kerth, C R; Bratcher, C L; Curtis, P A; Smith, B

    2012-03-01

    Beef inside round roasts (n=144) were cut from rounds obtained from both forage-finished cattle (n=72) and commercially-sourced beef (n=72). Roasts were portioned to weigh 0.45-0.68kg each. Each roast was then randomly assigned one of the following treatments: control, injected-no cure, or injected-cured. Additionally, roasts were assigned a serving temperature (hot or cold) and storage treatments (0d or 28d post cooking). Roasts from forage-fed beef had a more red interior color and higher shear values, and also retained more brine than commercially-sourced beef (P<0.05). Curing roasts improved TBARS values in roasts served hot and significantly reduced sensory warmed-over and grassy flavors (P<0.05). Marinating forage-finished beef roasts significantly improves tenderness and flavor characteristics. PMID:22118983

  16. Answer to Critical Remarks or one More Time About the Mechanism of Limitation on the Energy Characteristics of a Copper Vapor Laser

    NASA Astrophysics Data System (ADS)

    Yudin, N. A.

    2014-05-01

    This work presents an additional analysis of the main positions of the publication by N. A. Yudin, M. R. Tret'yakova, and N. N. Yudin, "Influence of electrophysical processes in the discharge circuit on the energy characteristics of a copper vapor laser" (Russ. Phys. J., 55, No. 9, 1080 - 1090 (2013)) in response to the conclusion drawn in the work of P. A. Bokhan "On the question of the existence of high-frequency oscillations in the power supply circuits of a copper vapor laser and their influence on the lasing mechanism" (Russ. Phys. J., 57, No. 1, 124 - 127 (2014)) that the main positions of the given publication are in error. The analysis performed here confirms the validity of the main positions of publication [2].

  17. [Effect of calcium hydroxide concentration and cooking time of corn grain (Zea mays L.) nixtamalized, over physicochemical and rheological nixtamal characteristics].

    PubMed

    Castillo, V K C; Ochoa, M l A; Figueroa, C J D; Delgado, L E; Gallegos, I J A; Morales, C J

    2009-12-01

    The effect of calcium hydroxide (Ca(OH)2) concentration and cooking time on physicochemical and pasting properties of maize, during traditional nixtamalization was evaluated. It was observed that the higher the Ca(OH)2 concentration and cooking time the higher the gelatinization temperature. Grain samples treated with 2 g/100 g of Ca(OH)2 and 60 min of cooking time presented higher calcium absorption (0.152 g/100 g) showing a significant increment (approximately 500 g/100 g). Results of X-ray diffraction showed that all the samples had X-ray diffraction pattern of starch type A, showing differences in the intensity of the diffraction as indicated by the percentage of cristallinity. The apparent viscosity of the nixtamal considerably decreased when the processes conditions were higher. Water retention capacity increased with temperature. PMID:20677458

  18. Determination of the time delay in the case of two-path propagation on the basis of the attenuation characteristics for two adjacent frequencies

    NASA Technical Reports Server (NTRS)

    Gilroi, H. G.

    1979-01-01

    Pronounced fading occurring in the line of sight radio links at frequencies below 10 GHz can be traced to the effects of multipath propagation. Modulation disturbances depend on travel time differences between the direct wave and the wave which is reflected at atmospheric layers. A method described for the determination of the time delay is based on an indirect approach which utilizes the difference in fading at various frequencies. The method was employed in measurements involving a distance of 181 km. The results obtained in the measurement are discussed.

  19. Critical Reynolds number of the couette flow of a vibrationally excited diatomic gas energy approach

    NASA Astrophysics Data System (ADS)

    Grigor'ev, Yu. N.; Ershov, I. V.

    2012-07-01

    An energy balance equation for plane-parallel flows of a vibrationally excited diatomic gas described by a two-temperature relaxation model is derived within the framework of the nonlinear energy theory of hydrodynamic stability. A variational problem of calculating critical Reynolds numbers Recr determining the lower boundary of the possible beginning of the laminar-turbulent transition is considered for this equation. Asymptotic estimates of Recr are obtained, which show the characteristic dependences of the critical Reynolds number on the Mach number, bulk viscosity, and relaxation time. A problem for arbitrary wave numbers is solved by the collocation method. In the realistic range of flow parameters for a diatomic gas, the minimum critical Reynolds numbers are reached on modes of streamwise disturbances and increase approximately by a factor of 2.5 as the flow parameters increase.

  20. Derivation of Ground Settlement Spatiotemporal Characteristics of Reclaimed Area in Nanhui New City, Shanghai, China, from Time-Series InSAR Interpretation

    NASA Astrophysics Data System (ADS)

    Zhao, Qing; Pepe, Antonio; Gao, Wei; Li, Xiaofeng; Lu, Zhong; Bonano, Manuela; Manunta, Michele; Lanari, Riccardo

    2014-11-01

    The Persistent Scatterer Interferometry (PSI) and the Small BAseline Subset (SBAS) techniques are employed to determine settlement rates and subsidence history of Nanhui New City, Shanghai, China. Inter-comparison of settlement results between ASAR PSI and ASAR SBAS, and their validation against levelling survey measurements are carried out to access the accuracy of DInSAR observations. Comparing DInSAR derived ground deformation map to alluvial deposit distribution in Nanhui New City, we find that the trend of ground settlement depends on the type of alluvial deposit and consolidation time. The Ensemble Empirical Mode Decomposition (EEMD) is adopted to obtain the trends of ASAR PSI, ASAR SBAS, and levelling time series measurements at a typical levelling benchmark. The results show that the three data sets follow almost the same trend.

  1. Annealing time dependence of the physical, electrical and pH response characteristics of spin coated TiO2 thin films

    NASA Astrophysics Data System (ADS)

    Zulkefle, M. A.; Rahman, R. A.; Yusoff, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

    2015-11-01

    Titanium dioxide (TiO2) thin film was deposited on indium tin oxide (ITO) substrate and used as sensing membrane of EGFET pH sensor. The thin film was fabricated using sol- gel spin coating method. All samples were annealed at 400 °C but the annealing time was varied. This is done to study the effects of annealing time on physical and electrical properties of titanium dioxide thin film. The sensitivity of each sample towards H+ ion was measured and result shows that sample annealed for 45 minutes has the highest sensitivity (52.6 mV/pH). It is found that increasing annealing duration will increase the pH sensitivity but a limit will be reached at certain point. Longer annealing processes done beyond this point will results in lower pH sensitivity.

  2. Real-time measurements of ambient aerosols in a polluted Indian city: Sources, characteristics, and processing of organic aerosols during foggy and nonfoggy periods

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhishek; Bhattu, Deepika; Gupta, Tarun; Tripathi, Sachchida N.; Canagaratna, Manjula R.

    2015-09-01

    A detailed time-resolved chemical characterization of ambient nonrefractory submicron aerosols (NR-PM1) was conducted for the first time in India. The measurements were performed during the winter (November 2011 to January 2012) in a heavily polluted city of Kanpur, which is situated in the Indo-Gangetic Plain. Real-time measurements provided new insights into the sources and evolution of organic aerosols (OA) that could not be obtained using previously deployed filter-based measurements at this site. The average NR-PM1 loading was very high (>100 µg/m3) throughout the study, with OA contributing approximately 70% of the total aerosol mass. Source apportionment of the OA using positive matrix factorization revealed large contributions from fresh and aged biomass burning OA throughout the entire study period. A back trajectory analysis showed that the polluted air masses were affected by local sources and distant source regions where the burning of paddy residues occurs annually during winter. Several fog episodes were encountered during the study, and the OA composition varied between foggy and nonfoggy periods, with higher oxygen to carbon (O/C) ratios during the foggy periods. The evolution of OA and their elemental ratios (O:C and H:C) were investigated for the possible effects of fog processing.

  3. Use of the receiver operating characteristic curve to evaluate sensitivity, specificity, and accuracy of methods for detection of peaks in hormone time series.

    PubMed

    Genazzani, A D; Rodbard, D

    1991-03-01

    We utilize the "Receiver Operating Characteristic" to describe the relationship between sensitivity and specificity as the threshold for peak detection is varied systematically, to provide objective comparison of the performance of methods for detection of episodic hormonal secretion. A computer program was used to generate synthetic data with peaks with variable durations, with constant or variable height, shape and/or interpulse interval. This approach was used to compare the CLUSTER and DETECT programs. For both programs, the observed false positive rates estimated using signal-free data were in good agreement with the nominal rates, but in the presence of signal the observed false positive rates were systematically lower. Sensitivity increases with increasing signal/noise ratio, as expected. Program DETECT, using its standard options, provided excellent sensitivity (90-100%) with very low false positive rate under all conditions tested. Its performance could be further improved by the use of a more stringent definition of a peak requiring the presence of "UP" followed by a "DOWN". The CLUSTER program was found to have very poor sensitivity when using the "local variance" option. Use of the true fixed standard deviation or percent coefficient of variation resulted in a modest improvement. Optimal performance of program CLUSTER was obtained by the use of the best of 3 variance models, testing 12 different cluster sizes (from 1x1 to 4x4) and selecting the best among these: under these conditions it can achieve high sensitivity (90-100%) for very low observed false positive rate, such that its performance was comparable to that of DETECT. The methods developed and illustrated here should permit the definitive characterization and validation of the performance of any one method, the objective comparison of the relative performance of two or more methods for analysis of pulsatile hormone levels for episodic hormone secretion, and lead to the improvement of algorithms for peak detection. PMID:2011919

  4. An analysis of characteristics for change in night light distribution from 1980 s to 1990 s by the time series global dmsp mosaic data

    NASA Astrophysics Data System (ADS)

    Nakayama, Y.; Tanaka, S.; Mitsugi, R.

    The Defense Meteorological Satellite Program (DMSP) Operation Linescan System (OLS) data observing night light distribution on the earth's surface have been archived since the 1970's. The major light distribution on the earth detected by the OLS sensorthe city lights, the forest fire, burning of shifting cultivation, the flame of the gas combustion in the oil fields and the fishing fire of boats due to human activities. In this study, a global DMSP/OLS mosaic data set on the latter half in the 1990's which can be compared with a global DMSP/OLS mosaic one in the 1980's was newly produced after the processing for radiometric and geometric corrections to several OLS original data. Next, the characteristics of night lights distribution and their change in about 10 years from the 1980's to the 1990's were analyzed in detail through the comparison of two global mosaic data on the 1980's and the latter half in the 1990's. Some satellite images in the daytime, geographical information data and the other auxiliary sources were used for the analysis of the change situation of night lights distribution. Finally, the relationship between changes in night light distribution and situation of human activities of the world were discussed. The analysis results clearly showed the expansion of light distribution pattern in several big cities due to the increase of energy consumption depending on the population growth. And, changes in the geographical distribution of the lights from biomass burning by the development of agricultural land and the shifting cultivation due to the increase of population could be grasped evidently.

  5. Effects of preslaughter feed withdrawal time on finishing pig carcass, body weight gain, and food safety characteristics in a commercial environment.

    PubMed

    Frobose, H L; Dritz, S S; Tokach, M D; Prusa, K J; DeRouchey, J M; Goodband, R D; Nelssen, J L

    2014-08-01

    The effects of feed withdrawal time before slaughter on finishing pig carcass composition were evaluated in 2 studies. In Exp. 1, 728 pigs (BW = 128.9 ± 1.2 kg) were allotted to 1 of 4 treatments in a randomized design with number of pigs per pen and location within barn balanced across treatment. The 4 treatments were feed withdrawal times of 8, 24, 36, or 48 h and there were 12 replicate pens per treatment. Before feed withdrawal, pigs were fed a standard corn-soybean meal diet containing dried distillers grains with solubles (DDGS), bakery coproducts, and 5.0 mg/kg ractopamine HCl. Feed withdrawal time decreased (linear; P < 0.02) live weight, HCW, and backfat while increasing percentage yield (quadratic; P < 0.01) and fat-free lean index (FFLI; linear; P < 0.001). In Exp. 2, 843 pigs (BW = 125.4 ± 1.6 kg) were used to determine the impact of feed withdrawal on growth, carcass, blood lactate, and meat quality. There were 4 treatments: withholding feed for 8, 12, 24, or 36 h, with 10 replicates per treatment. Pigs were fed a common corn-soybean meal-based diet containing 20% DDGS and 5.0 mg/kg ractopamine HCl. Withholding feed decreased (linear; P < 0.001) live weight, ultimately resulting in decreased (P < 0.01) HCW. There were no differences in FFLI or backfat, but percentage yield (linear; P < 0.001) increased with longer withdrawal times. Carcass contaminations by stomach contents escaping from the oral cavity after shackling (leaking ingesta) or visible fecal contamination of the exterior of the carcass (runny bung) were also measured. Although withholding feed did not affect runny bung, it increased (linear; P < 0.001) the incidence of leaking ingesta, whereas blood lactate, visual color score, and purge loss were unaffected. Withholding feed increased 45-min pH (quadratic; P > 0.02) and ultimate pH (linear; P < 0.01) and increased (quadratic; P < 0.03) visual marbling score. Withholding feed decreased (linear; P < 0.001) feed intake, resulting in feed savings of up to 3 kg/pig. Although several heavyweight pigs were removed before trial commencement and the variable number of remaining pigs per pen may have influenced the response to feed withdrawal, the present data indicates that finishing pigs can experience between 24 and 36 h of feed withdrawal without negatively affecting carcass composition. However, the increased incidence of leaking ingesta beyond 12 h of feed withdrawal is concerning. PMID:24987068

  6. Resolving the EGF-EGFR interaction characteristics through a multiple-temperature, multiple-inhibitor, real-time interaction analysis approach

    PubMed Central

    BJÖRKELUND, HANNA; GEDDA, LARS; MALMQVIST, MAGNUS; ANDERSSON, KARL

    2013-01-01

    Overexpression and aberrant activity of the epidermal growth factor (EGF) have been observed in various cancer types, rendering it an important target in oncology research. The interaction between EGF and its receptor (EGFR), as well as subsequent internalization, is complex and may be affected by various factors including tyrosine kinase inhibitors (TKIs). By combining real-time binding curves produced in LigandTracer® with internalization assays conducted at different temperatures and with different TKIs, the processes of ligand binding, internalization and excretion was visualized. SKOV3 cells had a slower excretion rate compared to A431 and U343 cells, and the tested TKIs (gefitinib, lapatinib, AG1478 and erlotinib) reduced the degree of internalization. The kinetic analysis of the binding curves further demonstrated TKI-dependent balances of EGFR monomer and dimer populations, where lapatinib promoted the monomeric form, while the other TKIs induced dimers. The dimer levels were found to be associated with the apparent affinity of the EGF-EGFR interaction, with EGF binding stronger to EGFR dimers compared to monomers. This study analyzed how real-time molecular interaction analysis may be utilized in combination with perturbations in order to understand the kinetics of a ligand-receptor interaction, as well as some of its associated intracellular processes. Our multiple-temperature and -inhibitor assay setup renders it possible to follow the EGFR monomer, dimer and internalized populations in a detailed manner, allowing for a new perspective of the EGFR biology. PMID:24649173

  7. Influence of soil properties and climate characteristics on transpirable soil water for two varieties with differences in their crop cycle timing

    NASA Astrophysics Data System (ADS)

    Ramos, Maria C.

    2014-05-01

    This paper presents an analysis of soil water content in two vineyards planted with Chardonnay and Cabernet Sauvignon in the Penedès Designation of Origin (DO). Climate is Mediterranean with maritime influence. The main soil types are Typic Xerorthent and Fluventic Haploxerept and soil is bare most of the time to avoid the competition of weeds for water. The plantation pattern was uniform in both cultivars, 1.3*3m. Soil moisture was analysed at each area from 10 to 90 cm every 20 cm, using TDF probes during two crop growing cycles (2010-2012). Soil water balance for years with different rainfall amount and distribution throughout the year was simulated using the Soil and Water Assessment Tool (SWAT). Differences in phenology of about one month existed among both varieties. In addition, the soil hydrological properties variability, resulted from land levelling operations before vineyard establishment, affects crop's soil water availability. These two facts made that, under the same rainfall amount and distribution, water available during the crop cycle were different for both varieties. The transpirable soil water fraction reached very low values, close to 0.1, particularly in the variety with early phenology timing. This pattern was repeated in different years depending on rainfall distribution, which affected grape production with significant yield reductions (up to 38% in relation to the average were found in some years).

  8. Ovarian characteristics and timed artificial insemination pregnancy risk after presynchronization with gonadotropin-releasing hormone 7 days before PGF2α in dairy cows.

    PubMed

    Stevenson, J S

    2016-04-01

    The objective was to determine the benefit of including GnRH and PGF2α (PG) as a part of a presynchronization option before enrolling cows in a timed artificial insemination (AI) program. Holstein cows in one herd were assigned weekly at calving from January 2012 to August 2014 to a completely randomized design consisting of two presynchronization treatments. Cows in the Presynch-11 (n = 290) control were administered two PGF2α injections (Presynch PG-1 and Presynch PG-2) 14 days apart starting at 39 ± 4 days postpartum (study Days 0 and 14). Cows receiving the experimental presynchronization treatment (Gsynch-11, n = 287) were treated with GnRH (pre-GnRH) on study Day 7 and PG (pre-PG) on study Day 14. On study Day 25, all cows were enrolled in the Ovsynch-56 timed AI program: GnRH-1 on study Day 25, PG on study Day 32, GnRH-2 on study Day 34, 56 hours after PG, and timed AI on study Day 35, 16 hours after GnRH-2. In a subsample of 255 cows, ovarian structures were monitored for size and ovulation, and blood samples were collected on study Days 7, 14, 25, 32, 34, and 41 to measure progesterone. Concentrations of progesterone were greater (P < 0.05) in Gsynch-11 than Presynch-11 cows before pre-GnRH was administered (3.3 ± 0.3 vs. 2.1 ± 0.3 ng/mL), respectively, and ovulatory response to the pre-GnRH treatment also was greater (P = 0.008) in Gsynch-11 than Presynch-11 cows (53.2 vs. 35.0%), respectively. One week later, the dominant follicle was larger (P = 0.045) in Presynch-11 than Gsynch-11 cows. Eleven days after completing the presynchronization treatments, ovulatory response to the Ovsynch GnRH-1 treatment was greater (P = 0.016) in Presynch-11 than Gsynch-11 cows (62.2% vs. 45.6%), respectively. At the time of the Ovsynch-PG treatment, more (P = 0.019) Presynch-11 than Gsynch-11 cows had at least one CL. Subsequent luteal regression (>96%), ovulation to GnRH-2 (>90%), and synchronization risk (>88%) did not differ between treatments, but incidence of multiple ovulation after GnRH-2 was larger (P = 0.036) in Presynch-11 than Gsynch-11 cows (28.4% vs. 15.9%), respectively. Pregnancy per AI at 32 days (36.4% vs. 35.1%) and 60 days (30.0% vs. 29.0%) after AI did not differ between Gsynch-11 and Presynch-11 cows, respectively, but was suppressed during summer months in both treatments to less than 70% of the pregnancy per AI of nonsummer months. Because more than 90% of the cows were ovular as treatments were applied, the GnRH treatment of Gsynch-11 could not be assessed for its benefit in anovular cows. The Gsynch-11 presynchronization treatment performed comparably with the standard Presynch-11 program and provides a viable presynchronization option for use before first AI in dairy herds. PMID:26739530

  9. A survey on time and frequency characteristics of induction motors with broken rotor bars in line-start and inverter-fed modes

    NASA Astrophysics Data System (ADS)

    Ghorbanian, Vahid; Faiz, Jawad

    2015-03-01

    This paper deals with the comprehensive detailed concepts of the rotor broken bars fault in industrial induction motors. It reviews the most important and applicable techniques for fault detection, and addresses fault diagnosing procedures at different supply modes including line-start and inverter-fed modes. Moreover, new analytical and experimental aspects of fault are proposed using the time and frequency domain variations of the motor variables such as current, voltage, electromagnetic torque and speed. Since the faulty motor behavior cannot be correctly identified without considering the motor operating condition, and the capability of the previous fault indicators are studied deeply in order to investigate their applicability at different conditions. These conditions include various faults, load and reference speed levels and also fault location. All in all, a precise condition assessment of the rotor broken bar induction motors, suitable for industrial purposes, is presented considering motor supply and conditions changes.

  10. EMBEDDED PROTOSTARS IN THE DUST, ICE, AND GAS IN TIME (DIGIT) HERSCHEL KEY PROGRAM: CONTINUUM SEDs, AND AN INVENTORY OF CHARACTERISTIC FAR-INFRARED LINES FROM PACS SPECTROSCOPY

    SciTech Connect

    Green, Joel D.; Evans, Neal J. II; Rascati, Michelle R.; Jorgensen, Jes K.; Dionatos, Odysseas; Lindberg, Johan E.; Herczeg, Gregory J.; Kristensen, Lars E.; Yildiz, Umut A.; Van Kempen, Tim A.; Lee, Jeong-Eun; Salyk, Colette; Meeus, Gwendolyn; Bouwman, Jeroen; Visser, Ruud; Bergin, Edwin A.; Van Dishoeck, Ewine F.; Karska, Agata; Fedele, Davide; Dunham, Michael M.; Collaboration: DIGIT Team1

    2013-06-20

    We present 50-210 {mu}m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 {mu}m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H{sub 2}O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 {yields} 13 up to J = 40 {yields} 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 {mu}m [O I] flux ratio is 17.2 {+-} 9.2. The [O I] 63 {mu}m line correlates with L{sub bol}, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L{sub bol} increased by 1.25 (1.06) and T{sub bol} decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ( = (0.70 {+-} 1.12) x 10{sup 49} total particles). N{sub CO} correlates strongly with L{sub bol}, but neither T{sub rot} nor N{sub CO}(warm)/N{sub CO}(hot) correlates with L{sub bol}, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H{sub 2}O ( = 194 +/- 85 K) and OH ( = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines.

  11. Comparison of the Detection Characteristics of Trace Species Using Laser-Induced Breakdown Spectroscopy and Laser Breakdown Time-of-Flight Mass Spectrometry

    PubMed Central

    Wang, Zhenzhen; Deguchi, Yoshihiro; Yan, Junjie; Liu, Jiping

    2015-01-01

    The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS) and laser breakdown time-of-flight mass spectrometry (LB-TOFMS). Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application. PMID:25769051

  12. Real-Time Digital Data-Acquisition System for determining load characteristics. Volume 2. Operating, programming, and maintenance instructions. Final report

    SciTech Connect

    Podesto, B.; Lapointe, A.; Larose, G.; Robichaud, Y.; Vaillancourt, C.

    1981-03-01

    The work sponsored under this contract included the design and construction of a Real-Time Digital Data Acquisition System (RTDDAS) to be used in substations for on-site recording and pre-processing load response data. The gathered data can be partially processed on site to compute the apparent, active and reactive powers, voltage and current rms values, and instantaneous values of phase voltages and currents. On-site processing capability is provided for rapid monitoring of the field data to ensure that the test setup is suitable. Production analysis of field data is accomplished off-line on a central computer from data recorded on a dual-density (800/1600) magnetic tape which is IBM-compatible. Parallel channels of data can be recorded at a variable rate from 480 to 9000 samples per second per channel. The RTDDAS is housed in a 9.1 m (30-ft) trailer which is shielded from electromagnetic interference and protected by isolators from switching surges; therefore, it can operate safely in a high-voltage substation environment where the tests must sometimes be performed. Information pertaining to the installation, software operation, and maintenance of the RTDDAS designed by IREQ is presented. A list of supporting documentation supplied by Data General Corporation is given.

  13. Effects of in ovo injection of organic trace minerals and post-hatch holding time on broiler performance and bone characteristics.

    PubMed

    Oliveira, T F B; Bertechini, A G; Bricka, R M; Hester, P Y; Kim, E J; Gerard, P D; Peebles, E D

    2015-11-01

    Effects of the in ovo injection of organic Mn, Zn, and Cu in association with post-hatch (POH) feed and water restriction on the performance and physical-chemical bone parameters of male Ross × Ross 708 broilers were examined. On 17 d of incubation, a total of 1,872 eggs were subjected to in ovo injection using a commercial multi-egg injector. Treatments (TRT) includingd non-injected and diluent-injected controls. The respective Zn, Mn, and Cu levels (mg/mL) added to the diluent of the low (LMD) and high mineral (HMD) TRT groups were 0.181, 0.087, and 0.010, and 0.544, 0.260, and 0.030, respectively. The 4 TRT groups were then sub-divided into 2 POH holding time (HT) groups, with 15 birds randomly allocated to each of 6 replicate pens in each of the 8 groups. The first HT group (0HT) had immediate access to water and feed, and the second HT group (24HT) contained birds that were kept in transport baskets for 24 h before being released. Performance was determined and selected birds were subsequently necropsied and their tibiae extracted for analysis. In comparison to birds from 24HT group, those in the 0HT group had a higher BW gain and feed intake, and a lower FCR through 21 d POH. The percentage of bone ash of the birds belonging to the HMD group was higher than all other TRT on d 1 POH and was higher than the non-injection control group on d 21 POH. On d 1, the LMD and HMD groups had higher tibial Mn concentrations than those of the control groups. On d 7, bones from the HMD group had a higher concentration of Mn than did the non-injected control group, and likewise, on d 21 POH, had a higher concentration of Zn than did the control groups. In conclusion, a 24HT negatively affected the performance of the birds during the first 2 wk POH; however, the LMD and HMD TRT had a positive influence on bone mineralization. PMID:26450915

  14. Effect of the time of day and queue position in the endoscopic schedule on the performance characteristics of endoscopic ultrasound-guided fine-needle aspiration for diagnosing pancreatic malignancies

    PubMed Central

    Korenblit, Jason; Tholey, Danielle M.; Tolin, Joanna; Loren, David; Kowalski, Thomas; Adler, Douglas G.; Davolos, Julie; Siddiqui, Ali A.

    2016-01-01

    Background and Objectives: Recent reports have indicated that the time of day may impact the detection rate of abnormal cytology on gynecologic cytology samples. The aim of this study was to determine if procedure time or queue position affected the performance characteristics of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for diagnosing solid pancreatic malignancies. Patients and Methods: We conducted a retrospective study evaluating patients with solid pancreatic lesions in whom EUS-FNA was performed. Three timing variables were evaluated as surrogate markers for endoscopist fatigue: Procedure start times, morning versus afternoon procedures, and endoscopy queue position. Statistical analyses were performed to determine whether the timing variables predicted performance characteristics of EUS-FNA. Results: We identified 609 patients (mean age: 65.8 years, 52.1% males) with solid pancreatic lesions who underwent EUS-FNA. The sensitivity of EUS-FNA was 100% for procedures that started at 7 AM while cases that started at 4 PM had a sensitivity of 81%. Using start time on a continuous scale, each elapsed hour was associated with a 1.9% decrease in EUS-FNA sensitivity (P = 0.003). Similarly, a 10% reduction in EUS-FNA sensitivity was detected between morning and afternoon procedures (92% vs. 82% respectively, P = 0.0006). A linear regression comparing the procedure start time and diagnostic accuracy revealed a decrease of approximately 1.7% in procedure accuracy for every hour later a procedure was started. A 16% reduction in EUS-FNA accuracy was detected between morning and afternoon procedures (100% vs. 84% respectively, P = 0.0009). When the queue position was assessed, a 2.4% reduction in accuracy was noted for each increase in the queue position (P = 0.013). Conclusion: Sensitivity and diagnostic accuracy of EUS-FNA for solid pancreatic lesions decline with progressively later EUS starting times and increasing numbers of procedures before a given EUS, potentially from endoscopist fatigue and cytotechnologist fatigue. PMID:27080605

  15. Height and time characteristics of seasonal and diurnal variations in PMWE based on 1 year observations by the PANSY radar (69.0°S, 39.6°E)

    NASA Astrophysics Data System (ADS)

    Nishiyama, Takanori; Sato, Kaoru; Nakamura, Takuji; Tsutsumi, Masaki; Sato, Toru; Kohma, Masashi; Nishimura, Koji; Tomikawa, Yoshihiro; Ejiri, Mitsumu K.; Tsuda, Takuo T.

    2015-04-01

    We report height and time variations in polar mesosphere winter echoes (PMWE) based on the Program of the Antarctic Syowa mesosphere-stratosphere-troposphere/incoherent scatter (PANSY) radar observations. PMWE were identified for 110 days from March to September 2013. PMWE occurrence frequency increased abruptly in May when two solar proton events occurred. PMWE were also observed even during periods without any solar proton events, suggesting that a possible cause of the PMWE is ionization by energetic electron precipitations. The monthly mean PMWE characteristics showed that occurrence of PMWE were mainly restricted to sunlit time. This fact indicates that electrons detached from negatively charged particles play an important role. While PMWE below 72 km in altitude completely disappeared before sunset, it was detected above that altitude for a few hours even after sunset. This height dependence in the altitude range of 60-80 km can be explained qualitatively by empirical effective recombination rates.

  16. Characteristic Curves.

    ERIC Educational Resources Information Center

    Walkiewicz, Thomas A.; Kirk, James R.

    1994-01-01

    Describes an experiment designed to help students gain a better understanding of the characteristics of various electronic components by incorporating a dual-trace oscilloscope in the X-Y mode in addition to direct observations of phase shifts of various signals into a laboratory exercise. (ZWH)

  17. Individual, family and offence characteristics of high risk childhood offenders: comparing non-offending, one-time offending and re-offending Dutch-Moroccan migrant children in the Netherlands

    PubMed Central

    2011-01-01

    Background Childhood offenders are at an increased risk for developing mental health, social and educational problems later in life. An early onset of offending is a strong predictor for future persistent offending. Childhood offenders from ethnic minority groups are a vulnerable at-risk group. However, up until now, no studies have focused on them. Aims To investigate which risk factors are associated with (re-)offending of childhood offenders from an ethnic minority. Method Dutch-Moroccan boys, who were registered by the police in the year 2006-2007, and their parents as well as a control group (n = 40) were interviewed regarding their individual and family characteristics. Two years later a follow-up analysis of police data was conducted to identify one-time offenders (n = 65) and re-offenders (n = 35). Results All groups, including the controls, showed substantial problems. Single parenthood (OR 6.0) and financial problems (OR 3.9) distinguished one-time offenders from controls. Reading problems (OR 3.8), having an older brother (OR 5.5) and a parent having Dutch friends (OR 4.3) distinguished re-offenders from one-time offenders. First offence characteristics were not predictive for re-offending. The control group reported high levels of emotional problems (33.3%). Parents reported not needing help for their children but half of the re-offender's families were known to the Child Welfare Agency, mostly in a juridical framework. Conclusion The Moroccan subgroup of childhood offenders has substantial problems that might hamper healthy development. Interventions should focus on reaching these families tailored to their needs and expectations using a multi-system approach. PMID:22014276

  18. A retrospective study on anthropometrical, physical fitness and motor coordination characteristics that influence drop out, contract status and first-team playing time in high-level soccer players, aged 8 to 18 years.

    PubMed

    Deprez, Dieter; Fransen, Job; Lenoir, Matthieu; Philippaerts, Renaat M; Vaeyens, Roel

    2014-12-01

    The goal of this manuscript was twofold and a two-study approach was conducted. The first study aimed to expose the anthropometrical, physical performance and motor coordination characteristics that influence drop out from a high-level soccer training program in players aged 8-16 years. The mixed-longitudinal sample included 388 Belgian youth soccer players who were assigned to either a 'club group' or a 'drop out group'. In the second study, cross-sectional data of anthropometry, physical performance and motor coordination were retrospectively explored to investigate which characteristics influence future contract status (contract vs. no contract group) and first-team playing time for 72 high-level youth soccer players (mean age=16.2 y).Generally, club players outperformed their drop out peers for motor coordination, soccer-specific aerobic endurance and speed. Anthropometry and estimated maturity status did not discriminate between club and drop out players. Contract players jumped further (p=0.011) and had faster times for a 5m sprint (p=0.041) than no contract players. The following prediction equation explains 16.7% of the variance in future playing minutes in adolescent youth male soccer players: -2869.3 + 14.6 * standing broad jump.Practitioners should include the evaluation of motor coordination, aerobic endurance and speed performances to distinguish high-level soccer players further succeeding a talent development program and future drop out players, between 8 and 16 years. From the age of 16 years, measures of explosivity are supportive when selecting players into a future professional soccer career. PMID:25474335

  19. A retrospective study on anthropometrical, physical fitness, and motor coordination characteristics that influence dropout, contract status, and first-team playing time in high-level soccer players aged eight to eighteen years.

    PubMed

    Deprez, Dieter N; Fransen, Job; Lenoir, Matthieu; Philippaerts, Renaat M; Vaeyens, Roel

    2015-06-01

    The goal of this article was twofold, and a 2-study approach was conducted. The first study aimed to expose the anthropometrical, physical performance, and motor coordination characteristics that influence dropout from a high-level soccer training program in players aged 8-16 years. The mixed-longitudinal sample included 388 Belgian youth soccer players who were assigned to either a "club group" or a "dropout group." In the second study, cross-sectional data of anthropometry, physical performance, and motor coordination were retrospectively explored to investigate which characteristics influence future contract status (contract vs. no contract group) and first-team playing time for 72 high-level youth soccer players (mean age = 16.2 years). Generally, club players outperformed their dropout peers for motor coordination, soccer-specific aerobic endurance, and speed. Anthropometry and estimated maturity status did not discriminate between club and dropout players. Contract players jumped further (p = 0.011) and had faster times for a 5-m sprint (p = 0.041) than no contract players. The following prediction equation explains 16.7% of the variance in future playing minutes in adolescent youth male soccer players: -2,869.3 + 14.6 × standing broad jump. Practitioners should include the evaluation of motor coordination, aerobic endurance, and speed performances to distinguish high-level soccer players further succeeding a talent development program and future dropout players, between 8 and 16 years. From the age of 16 years, measures of explosivity are supportive when selecting players into a future professional soccer career. PMID:26010800

  20. Decay time characteristics of La2O2S:Eu and La2O2S:Tb for use within an optical sensor for human skin temperature measurement.

    PubMed

    Yap, Sook Voon; Ranson, Robert M; Cranton, Wayne M; Koutsogeorgis, Demosthenes

    2008-09-20

    We focus on the development of a remote temperature sensing technology, i.e., an optical laser-based sensor, using thermographic phosphors for medical applications, particularly within an electromagnetically hostile magnetic resonance imaging (MRI) environment. A MRI scanner uses a strong magnetic field and radio waves to generate images of the inside of the body. The quality of the image improves with increasing magnetic resonance; however, the drawback of applying a greater magnetic strength is the inducement of heat into the body tissue. Therefore, monitoring the patient's temperature inside MRI is vital, but until now, a practical solution for temperature measurement did not exist. We show europium doped lanthanum oxysulphide (La(2)O(2)S:Eu) and terbium doped lanthanum oxysulphide (La(2)O(2)S:Tb) are both temperature sensitive to a low temperature range of 10-50 degrees C when under ultraviolet (UV) excitation. The emission spectra and decay time characteristics of these phosphors were demonstrated. The results indicate that La(2)O(2)S:Eu has a quenching rate of 13.7 m degrees C(-1) and 4 m degrees C(-1) at 512 nm and 538 nm, respectively. In addition, La(2)O(2)S:Tb has a lower quenching rate of 4.19 m degrees C(-1) at 548 nm due to its faster decay time. PMID:18806849

  1. Decay time characteristics of La2O2S:Eu and La2O2S:Tb for use within an optical sensor for human skin temperature measurement

    SciTech Connect

    Yap, Sook Voon; Ranson, Robert M.; Cranton, Wayne M.; Koutsogeorgis, Demosthenes

    2008-09-20

    We focus on the development of a remote temperature sensing technology, i.e., an optical laser-based sensor, using thermographic phosphors for medical applications, particularly within an electromagnetically hostile magnetic resonance imaging (MRI) environment. A MRI scanner uses a strong magnetic field and radio waves to generate images of the inside of the body. The quality of the image improves with increasing magnetic resonance; however, the drawback of applying a greater magnetic strength is the inducement of heat into the body tissue. Therefore, monitoring the patient's temperature inside MRI is vital, but until now, a practical solution for temperature measurement did not exist. We show europium doped lanthanum oxysulphide (La2O2S:Eu) and terbium doped lanthanum oxysulphide (La2O2S:Tb) are both temperature sensitive to a low temperature range of 10-50 deg. C when under ultraviolet (UV) excitation. The emission spectra and decay time characteristics of these phosphors were demonstrated. The results indicate that La2O2S:Eu has a quenching rate of 13.7 m deg. C{sup -1} and 4 m deg. C{sup -1} at 512 nm and 538 nm, respectively. In addition, La2O2S:Tb has a lower quenching rate of 4.19 m deg. C{sup -1} at 548 nm due to its faster decay time.

  2. Seasonal characteristics of fine particulate matter (PM) based on high resolution time-of-flight aerosol mass spectrometric (HR-ToF-AMS) measurements at the HKUST Supersite in Hong Kong

    NASA Astrophysics Data System (ADS)

    Li, Y. J.; Lee, B. P.; Su, L.; Fung, J. C. H.; Chan, C. K.

    2014-08-01

    Atmospheric particulate matter (PM) remains poorly understood due to the lack of comprehensive measurements at high time resolution for tracking its dynamic features and the lack of long-term observation for tracking its seasonal variability. Here, we present highly time-resolved and seasonal compositions and characteristics of non-refractory components in PM with diameter less than 1 ?m (NR-PM1) at a suburban site in Hong Kong. The measurements were made with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) at the Hong Kong University of Science and Technology (HKUST) Air Quality Research Supersite for four months, with one in each season of the year. The average NR-PM1 concentration of ~15 ?g m-3 is higher than those AMS measurements made in South Korea and Japan, but lower than those in North China, the Yangtze River Delta and the nearby Pearl River Delta. The seasonal dependence of the total NR-PM1 monthly averaged concentrations was small but that of the fractions of the species in NR-PM1 was significant. Site characteristic plays an important role in the relative fractions of species in NR-PM1 and our results are generally consistent with measurements at other non-urban sites in this regard. Detailed analyses were conducted on the AMS data in the aspects of (1) species concentrations, (2) size distributions, (3) degree of oxygenation of organics, and (4) positive matrix factorization (PMF)-resolved organic factors in a seasonal context, as well as with air mass origin from back-trajectory analysis. Sulfate had the highest fraction in NR-PM1 (> 40%) and the surrogates of secondary organic species, semi-volatile oxygenated organic aerosol (SVOOA) and low-volatility oxygenated organic aerosol (LVOOA), prevailed (~80%) in the organic portion of NR-PM1. Local contributions to the organic portion of NR-PM1 at this suburban site was strongly dependent on season. The hydrocarbon-like organic aerosol (HOA) factor related to local traffic emissions contributed > 10% to organic aerosols in spring and summer, but only 6-7% in autumn and winter. The cooking organic aerosol (COA) factor contributed > 10% to organic aerosols in winter. With the aid of highly time-resolved data, diurnal patterns of the degree of oxygenation of organic aerosols were used to determine the sources and formation processes of the least understood organic portion of PM. The oxygen-to-carbon atomic ratio (O : C) and average carbon oxidation state (OSC) showed little variation in autumn and winter when the long-range transport of oxidized organics dominated, whereas they peaked in the afternoon in spring and summer when locally produced secondary organic aerosol prevailed. Air mass origin, in contrast, had a strong influence on both NR-PM1 concentrations and the fractions of species in NR-PM1. The findings of the current study provide a better understanding of the role of air mass origin in the seasonal characteristics of the PM composition and the relative importance of local vs. transported organic aerosols in this region.

  3. Seasonal characteristics of fine particulate matter (PM) based on high-resolution time-of-flight aerosol mass spectrometric (HR-ToF-AMS) measurements at the HKUST Supersite in Hong Kong

    NASA Astrophysics Data System (ADS)

    Li, Y. J.; Lee, B. P.; Su, L.; Fung, J. C. H.; Chan, C. K.

    2015-01-01

    Atmospheric particulate matter (PM) remains poorly understood due to the lack of comprehensive measurements at high time resolution for tracking its dynamic features and the lack of long-term observation for tracking its seasonal variability. Here, we present highly time-resolved and seasonal compositions and characteristics of non-refractory components in PM with a diameter less than 1 μm (NR-PM1) at a suburban site in Hong Kong. The measurements were made with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) at the Hong Kong University of Science and Technology (HKUST) Air Quality Research Supersite for 4 months, with one in each season of the year. The average NR-PM1 concentration of ~ 15 μg m-3 is higher than those AMS measurements made in South Korea and Japan, but lower than those in North China, the Yangtze River Delta and the nearby Pearl River Delta. The seasonal dependence of the total NR-PM1 monthly averaged concentrations was small, but that of the fractions of the species in NR-PM1 was significant. Site characteristic plays an important role in the relative fractions of species in NR-PM1 and our results are generally consistent with measurements at other non-urban sites in this regard. Detailed analyses were conducted on the AMS data in the aspects of (1) species concentrations, (2) size distributions, (3) degree of oxygenation of organics, and (4) positive matrix factorization (PMF)-resolved organic factors in a seasonal context, as well as with air mass origin from back-trajectory analysis. Sulfate had the highest fraction in NR-PM1 (> 40%), and the surrogates of secondary organic species - semi-volatile oxygenated organic aerosol (SVOOA) and low-volatility oxygenated organic aerosol (LVOOA) - prevailed (~ 80%) in the organic portion of NR-PM1. Local contributions to the organic portion of NR-PM1 at this suburban site was strongly dependent on season. The hydrocarbon-like organic aerosol (HOA) factor related to local traffic emissions contributed > 10% to organic aerosols in spring and summer but only 6-7% in autumn and winter. The cooking organic aerosol (COA) factor contributed > 10% to organic aerosols in winter. With the aid of highly time-resolved data, diurnal patterns of the degree of oxygenation of organic aerosols were used to determine the sources and formation processes of the least understood organic portion of PM. The oxygen-to-carbon atomic ratio (O : C) and average carbon oxidation state OS C) showed little variation in autumn and winter, when the long-range transport of oxidized organics dominated, whereas they peaked in the afternoon in spring and summer, when locally produced secondary organic aerosol prevailed. Air mass origin, in contrast, had a strong influence on both NR-PM1 concentrations and the fractions of species in NR-PM1. The findings of the current study provide a better understanding of the role of air mass origin in the seasonal characteristics of the PM composition and the relative importance of local vs. transported organic aerosols in this region.

  4. Flow Structure and Mass Transfer Investigation of the Turbulized Boundary Layer with Ethanol Evaporation and Diffusion Combustion

    NASA Astrophysics Data System (ADS)

    Volchkov, E. P.; Boyarshinov, B. F.; Titkov, V. I.

    2002-07-01

    Uncertainty of evaluation of each factor (separation laminar-turbulent transition combustion and turbulization) hinders mathematical simulation of the joint effect on gas dynamic and thermal characteristics of the boundary layer. The characteristics may be most reliably determined experimentally. The work objective is the experimental study of the boundary layer structure comparison of the fields of temperature velocity and its pulsation with data on heat and mass transfer.

  5. Clinical characteristics, and time course of pancreatic beta-cell function and glutamic acid decarboxylase antibodies in Thai patients with adult-onset Type 1 diabetes: distinction between patients of rapid- and slow-onset.

    PubMed

    Rattarasarn, C; Diosdado, M A

    1999-05-01

    In order to study the clinical characteristics, time course of beta cell function and glutamic acid decarboxylase antibodies (GAD65Ab) in Thai patients with adult-onset Type 1 diabetes and to examine the distinctive features between patients with rapid-and slow-onset, 61 Thai patients with Type 1 diabetes who had age of disease onset at or after 20 years were studied. All patients were treated with insulin at the time of study and had fasting C-peptide levels +/-0.33 nmol/l. Twenty-six (42.6%) were in rapid-onset and 35 (57.4%) were in slow-onset groups. Fourty-four of 61 (70.5%) were male. About three-fourths had body mass index (BMI) < 19 kg/m2 at the time of insulin therapy. Only 7 of 61 (11.5%) patients had ketoacidosis at first presentation. Five patients had associated autoimmune thyroid disease and 10 (16.7%) patients had family history of diabetes in first-degree relatives. GAD65Ab was positive in 31 patients (50.8%); 10 (38.5%) were in rapid-onset and 21 (60.0%) were in slow-onset groups. GAD65Ab particularly of high levels were persistently elevated during 3-4 years follow-up period. The persistence of GAD65Ab were not associated with changes in fasting C-peptide levels. At the time of insulin dependency, there were no distinctive clinical features between rapid- and slow-onset patients except higher fasting C-peptide (0.08+/-0.08 vs. 0.14+/-0.10 nmol/l; p = 0.023) and GAD65Ab levels (19.6+/-17.4 vs. 46.1+/-49.7 U/ml; p = 0.036) in slow-onset patients. Fasting C-peptide levels of patients in the latter group were also demonstrated to be higher after 3-4 years of follow-up. In conclusion, most Thai patients with adult-onset Type 1 diabetes in this study were male and had significant degree of weight loss and lean BMI prior to insulin therapy. The presence of GAD65Ab did not predict clinical features or rate of beta cell loss. Patients in rapid-onset group had lower fasting C-peptide and GAD65Ab levels than those of slow-onset group which confirms the slower process of beta cell failure in the latter. PMID:10422726

  6. Predictors of delay discounting among smokers: education level and a Utility Measure of Cigarette Reinforcement Efficacy are better predictors than demographics, smoking characteristics, executive functioning, impulsivity, or time perception.

    PubMed

    Wilson, A George; Franck, Christopher T; Mueller, E Terry; Landes, Reid D; Kowal, Benjamin P; Yi, Richard; Bickel, Warren K

    2015-06-01

    Ninety-four smokers completed the delay discounting procedure for either hypothetical amounts of money, $10 (money) and $1000 (money) or hypothetical amounts of cigarettes ($10 and $1000 worth of cigarettes). We investigated how variables previously found to be related to rates of delay discounting accounted for the observed results. These variables included the following: demographic information, smoking characteristics, executive function abilities, impulsivity, time perception, and the Utility Measure of Cigarette Reinforcing Efficacy (UMCE). Education level and UMCE were each significantly correlated with 3 out of 4 of the discounting measures. Moreover, the largest effect sizes observed were between these two measures and the four discounting measures. All potential discounting predictors were also investigated using step-wise linear regression with Bayesian Information Criterion (BIC) analysisthese BIC models revealed that education level and UMCE accounted for large portions of the variance. We conclude that education level and UMCE were the most consistent predictors of discounting. This data is discussed within the framework of a widely accepted neuroeconomic model that suggests that two brain systems separately assess two separate facets of decision-making, and the interplay between these two systems determines self-control in smokers. We hypothesize that education level and UMCE may serve as surrogate measures of the functionality of these two systems and that discounting may be a sentinel measure of self-control. PMID:25661991

  7. Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics.

    ERIC Educational Resources Information Center

    Denoyer, Eric; And Others

    1982-01-01

    Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

  8. ILLIAC 4 systems characteristics and programming manual

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The latest edition is presented of the Systems Characteristics and Programming Manual of the ILLIAC 4 array and parallel disc memory system. The major aspects of the array described include: the array systems characteristics, programming characteristics, definition and flow charts, and timing. A glossary of terms, and an instruction index are included.

  9. Effects of Time Specific F-strain Mycoplasma gallisepticum Inoculation Overlays on Prelay ts-11-strain M. gallisepticum Vaccination on Digestive and Reproductive Organ Characteristics of Commercial Egg-Laying Hens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two trials were conducted to determine the effects of a prelay ts11-strain M. gallisepticum (ts11MG) vaccination alone or in conjunction with F-strain M. gallisepticum (FMG) inoculation overlays at 2 different age periods during lay on the digestive and reproductive organ characteristics of commerci...

  10. Three-dimensional modeling of diesel engine intake flow, combustion and emissions

    NASA Technical Reports Server (NTRS)

    Reitz, R. D.; Rutland, C. J.

    1992-01-01

    A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation, and the intake flow process. Improved and/or new submodels which were completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and finally, the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To date, comparisons with measured engine cylinder pressure and heat flux data were made for homogeneous charge, spark-ignited and compression-ignited engines. The model results are in good agreement with the experiments.

  11. Characteristics of Male Alcohol Offenders.

    ERIC Educational Resources Information Center

    Ratliff, Katharine G.; Ellis, Thomas E.

    Because most studies investigating psychological profiles of subjects convicted of driving under the influence of alcohol (DUI) have been conducted at the time of arrest or treatment, it is unclear whether subjects' anxiety, depression, and hostility represent "trait" characteristics central to alcohol abuse or "state" responses to arrest and

  12. Student Characteristics Report, Fall 1976.

    ERIC Educational Resources Information Center

    Metropolitan Community Colleges of Kansas City, MO. Div. of Planning and Development.

    As part of a continuing survey of student population characteristics at the Metropolitan Community Colleges, this report presents questionnaire responses of 14,630 regular credit enrollment students for fall 1976. Twenty-eight tables organize information by campus in terms of: male and female students by part- or full-time status; enrollment…

  13. Speech characteristics in depression.

    PubMed

    Stassen, H H; Bomben, G; Günther, E

    1991-01-01

    This study examined the relationship between speech characteristics and psychopathology throughout the course of affective disturbances. Our sample comprised 20 depressive, hospitalized patients who had been selected according to the following criteria: (1) first admission; (2) long-term patient; (3) early entry into study; (4) late entry into study; (5) low scorer; (6) high scorer, and (7) distinct retarded-depressive symptomatology. Since our principal goal was to model the course of affective disturbances in terms of speech parameters, a total of 6 repeated measurements had been carried out over a 2-week period, including 3 different psychopathological instruments and speech recordings from automatic speech as well as from reading out loud. It turned out that neither applicability nor efficiency of single-parameter models depend in any way on the given, clinically defined subgroups. On the other hand, however, no significant differences between the clinically defined subgroups showed up with regard to basic speech parameters, except for the fact that low scorers seemed to take their time when producing utterances (this in contrast to all other patients who, on the average, had a considerably shorter recording time). As to the relationship between psychopathology and speech parameters over time, we found significant correlations: (1) in 60% of cases between the apathic syndrome and energy/dynamics; (2) in 50% of cases between the retarded-depressive syndrome and energy/dynamics; (3) in 45% of cases between the apathic syndrome and mean vocal pitch, and (4) in 71% of low scores between the somatic-depressive syndrome and time duration of pauses. All in all, single parameter models turned out to cover only specific aspects of the individual courses of affective disturbances, thus speaking against a simple approach which applies in general. PMID:1886971

  14. Characteristics of Yerevan High Transparency Scintillators

    SciTech Connect

    Zorn, Carl; Asryan, Gegham; Egiyan, Kim; Tarverdyan, M.; Amaryan, Moscov; Amaryan, Moskov; Demirchyan, Raphael; Stepanyan, Stepan; Burkert, Volker; Sharabian, Youri

    1992-08-01

    Optical transmission, light output and time characteristics are given for long scintillator strips fabricated at the Yerevan Physics Institute using the extrusion method. It is shown that at 45% relative (to anthracene) light output, good transmission (2.5/2.9 m attenuation length with photomultiplier direct readout and 3/3.5 m attenuation length fiber readout) and time characteristics (average decay time 2.8 nsec) were obtained.

  15. The Use of a priori Information in ICA-Based Techniques for Real-Time fMRI: An Evaluation of Static/Dynamic and Spatial/Temporal Characteristics

    PubMed Central

    Soldati, Nicola; Calhoun, Vince D.; Bruzzone, Lorenzo; Jovicich, Jorge

    2013-01-01

    Real-time brain functional MRI (rt-fMRI) allows in vivo non-invasive monitoring of neural networks. The use of multivariate data-driven analysis methods such as independent component analysis (ICA) offers an attractive trade-off between data interpretability and information extraction, and can be used during both task-based and rest experiments. The purpose of this study was to assess the effectiveness of different ICA-based procedures to monitor in real-time a target IC defined from a functional localizer which also used ICA. Four novel methods were implemented to monitor ongoing brain activity in a sliding window approach. The methods differed in the ways in which a priori information, derived from ICA algorithms, was used to monitor a target independent component (IC). We implemented four different algorithms, all based on ICA. One Back-projection method used ICA to derive static spatial information from the functional localizer, off-line, which was then back-projected dynamically during the real-time acquisition. The other three methods used real-time ICA algorithms that dynamically exploited temporal, spatial, or spatial-temporal priors during the real-time acquisition. The methods were evaluated by simulating a rt-fMRI experiment that used real fMRI data. The performance of each method was characterized by the spatial and/or temporal correlation with the target IC component monitored, computation time, and intrinsic stochastic variability of the algorithms. In this study the Back-projection method, which could monitor more than one IC of interest, outperformed the other methods. These results are consistent with a functional task that gives stable target ICs over time. The dynamic adaptation possibilities offered by the other ICA methods proposed may offer better performance than the Back-projection in conditions where the functional activation shows higher spatial and/or temporal variability. PMID:23483841

  16. Skin characteristics in newborns

    MedlinePlus

    Newborn skin characteristics; Infant skin characteristics ... the first few weeks of the baby's life. Newborn skin will vary, depending on the length of the pregnancy. Premature infants have thin, transparent skin. The skin of a ...

  17. Wetland Characteristics and Denitrification

    EPA Science Inventory

    This presentation serves as an initial summary of our wetland field work's watershed characteristics hydrologic characteristics, water quality measurements, and denitrification assays. We present our measurement results in the context of wetland type (Estuarine, Freshwater Mars...

  18. Exploring Lightning Jump Characteristics

    NASA Technical Reports Server (NTRS)

    Chronis, Themis; Carey, Larry D.; Schultz, Christopher J.; Schultz, Elise; Calhoun, Kristin; Goodman, Steven J.

    2014-01-01

    This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to higher Maximum Expected Size of Hail, Vertical Integrated Liquid and lightning flash rates (area-normalized) than the clusters that did not exhibit any LJ (LJ0). The respective mean values for LJ1 (LJ0) clusters are 80 min (35 min), 14 mm (8 mm), 25 kg per square meter (18 kg per square meter) and 0.05 flash per min per square kilometer (0.01 flash per min per square kilometer). Furthermore, the LJ1 clusters are also characterized by slower decaying autocorrelation functions, a result that implies a less "random" behavior in the temporal flash rate evolution. In addition, the temporal occurrence of the last LJ provides an estimate of the time remaining to the storm's dissipation. Depending of the LJ strength (i.e., varying thresholds), these values typically range between 20-60 min, with stronger jumps indicating more time until storm decay. This study's results support the hypothesis that the LJ is a proxy for the storm's kinematic and microphysical state rather than a coincidental value.

  19. Invariant Characteristics of Carcinogenesis

    PubMed Central

    Sherman, Simon; Rathnayake, Nirosha; Mdzinarishvili, Tengiz

    2015-01-01

    Carcinogenic modeling is aimed at mathematical descriptions of cancer development in aging. In this work, we assumed that a small fraction of individuals in the population is susceptible to cancer, while the rest of the population is resistant to cancer. For individuals susceptible to cancer we adopted methods of conditional survival analyses. We performed computational experiments using data on pancreatic, stomach, gallbladder, colon and rectum, liver, and esophagus cancers from the gastrointestinal system collected for men and women in the SEER registries during 1975–2009. In these experiments, we estimated the time period effects, the birth cohort effects, the age effects and the population (unconditional) cancer hazard rates. We also estimated the individual cancer presentation rates and the individual cancer resistance rates, which are, correspondingly, the hazard and survival rates conditioned on the susceptibility to cancer. The performed experiments showed that for men and women, patterns of the age effects, the individual cancer presentation rates and the individual cancer resistance rates are: (i) intrinsic for each cancer subtype, (ii) invariant to the place of living of the individuals diagnosed with cancer, and (iii) well adjusted for the modifiable variables averaged at a given time period. Such specificity and invariability of the age effects, the individual cancer presentation rates and the individual cancer resistance rates suggest that these carcinogenic characteristics can be useful for predictive carcinogenic studies by methods of inferential statistics and for the development of novel strategies for cancer prevention. PMID:26465159

  20. Characteristics of Pulsating Aurora

    NASA Astrophysics Data System (ADS)

    Humberset, B. K.; Gjerloev, J. W.; Mann, I. R.; Samara, M.; Michell, R.

    2013-12-01

    We have investigated the spatiotemporal characteristics of pulsating auroral patches observed with an all-sky imager located at Poker Flat, Alaska. Pulsating aurora often covers the entire sky with intermixed large and small-scale patches that vary in intensity or disappear and reappear on different time scales and timings. The broad definition of pulsating aurora covers patches and bands from tens to several tens of km which have a quasi-periodic temporal variation from 1 s to tens of seconds. In this paper we examine >15 patches from different events. We analyze all-sky movies (557.7 nm, 3.31 Hz) with a simple, yet robust, technique that allows us to determine the scale size dependent variability of the >15 individual patches. A spatial 2D Fourier Transform is used to separate the aurora into different horizontal scale sizes, and by correlating each patch for all image separations and available scale sizes smaller than the patch itself, we reveal what scale sizes are pulsating and their variability. The patches are found to be persistent, meaning that we can follow them for typically 5 minutes. The period of the pulsations is often remarkably variable and it seems that only certain scale sizes pulsate (typically the size of the patch). The patches drift with the background ExB plasma drift indicating that the magnetospheric source mechanism drifts with the field lines.

  1. A proposal of the diagnosis-dynamic characteristic (DDC) model describing the relation between search time and confidence levels for a dichotomous judgment, and its application to ROC curve generation

    NASA Astrophysics Data System (ADS)

    Matsumoto, Toru; Fukuda, Nobuo; Furukawa, Akira; Suwa, Koji; Wada, Shinichi; Matsumoto, Mitsuomi; Sone, Shusuke

    2006-03-01

    When physicians inspect an image, they make up a certain degree of confidence that the image are abnormal; p(t), or normal; n(t)[n(t)=1-p(t)]. After infinite time of the inspection, they reach the equilibrium levels of the confidence of p*=p(∞) and n*=n(∞). There are psychological conflicts between the decisions of normal and abnormal. We assume that the decision of "normal" is distracted by the decision of "abnormal" by a factor of k(1 + ap), and in an inverse direction by a factor of k(1 + bn), where k ( > 0) is a parameter that relates with image quality and skill of the physicians, and a and b are unknown constants. After the infinite time of inspection, the conflict reaches the equilibrium, which satisfies the equation, k(1 + ap*)n* = k(1 + bn*)p*. Here we define a parameter C, which is 2p*/[p*(1 - p*)]. After the infinite time of inspection, the conflict reaches the equilibrium, which satisfies t that changes in the confidence level with the time (dp/dt) is proportional to [k(1+ap)n - k(1+bn)p], i.e. k[-cp2 + (c - 2)p + 1]. Solving the differential equation, we derived the equation; t(p) and p(t) depending with the parameters; k, c, S. S (0-1) is the value arbitrary selected and related with probability of "abnormal" before the image inspection (S = p(0)). Image reading studies were executed for CT images. ROC curves were generated both by the traditional 4-step score-based method and by the confidence level; p estimated from the equation t(p) of the DDC model using observed judgment time. It was concluded that ROC curves could be generated by measuring time for dichotomous judgment without the subjective scores of diagnostic confidence and applying the DDC model.

  2. Characteristic sounds facilitate visual search.

    PubMed

    Iordanescu, Lucica; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

    2008-06-01

    In a natural environment, objects that we look for often make characteristic sounds. A hiding cat may meow, or the keys in the cluttered drawer may jingle when moved. Using a visual search paradigm, we demonstrated that characteristic sounds facilitated visual localization of objects, even when the sounds carried no location information. For example, finding a cat was faster when participants heard a meow sound. In contrast, sounds had no effect when participants searched for names rather than pictures of objects. For example, hearing "meow" did not facilitate localization of the word cat. These results suggest that characteristic sounds cross-modally enhance visual (rather than conceptual) processing of the corresponding objects. Our behavioral demonstration of object-based cross-modal enhancement complements the extensive literature on space-based cross-modal interactions. When looking for your keys next time, you might want to play jingling sounds. PMID:18567253

  3. An outbreak of infections caused by extensively drug-resistant Klebsiella pneumoniae strains during a short period of time in a Chinese teaching hospital: epidemiology study and molecular characteristics.

    PubMed

    Zhou, Tieli; Zhang, Yapei; Li, Meimei; Yu, Xiao; Sun, Yao; Xu, Jiru

    2015-07-01

    In this study, we comprehensively described the clinical risk factors, outcome, epidemiology, and molecular basis associated with an outbreak of extensively drug-resistant KPC-2-producing Klebsiella pneumoniae involving 15 patients in a teaching hospital from May 1 to June 27, 2013. Most of the patients were elderly and received long-term hospital treatment, and 40.0% (6/15) of them were dead. All strains carried bla(KPC-2), rmtB, bla(CTX-M-65), bla(SHV-11), oqxA, oqxB, and aac(6')-Ib-cr and even harbored additional other resistance genes, such as armA, bla(CTX-M-1), bla(TEM-1). bla(KPC-2), rmtB, and bla(CTX-M-65) were located on the same ~54.2-kb plasmid, and conjugation experiments further proved the cotransferable characteristic. Alterations of outer membrane proteins were confirmed by sodium dodecyl sulfate--olyacrylamide gelelectrophoresis and sequencing, which can lead to a drastic change in the permeability of cells. All isolates belonged to the clone complex 258, spreading rapidly across the world. Our study demonstrated that a high degree of awareness and surveillance of those drug resistance determinants is urgently needed. PMID:25865067

  4. TaqMan real-time PCR assays to assess arbuscular mycorrhizal responses to field manipulation of grassland biodiversity: effects of soil characteristics, plant species richness, and functional traits.

    PubMed

    König, Stephan; Wubet, Tesfaye; Dormann, Carsten F; Hempel, Stefan; Renker, Carsten; Buscot, François

    2010-06-01

    Large-scale (temporal and/or spatial) molecular investigations of the diversity and distribution of arbuscular mycorrhizal fungi (AMF) require considerable sampling efforts and high-throughput analysis. To facilitate such efforts, we have developed a TaqMan real-time PCR assay to detect and identify AMF in environmental samples. First, we screened the diversity in clone libraries, generated by nested PCR, of the nuclear ribosomal DNA internal transcribed spacer (ITS) of AMF in environmental samples. We then generated probes and forward primers based on the detected sequences, enabling AMF sequence type-specific detection in TaqMan multiplex real-time PCR assays. In comparisons to conventional clone library screening and Sanger sequencing, the TaqMan assay approach provided similar accuracy but higher sensitivity with cost and time savings. The TaqMan assays were applied to analyze the AMF community composition within plots of a large-scale plant biodiversity manipulation experiment, the Jena Experiment, primarily designed to investigate the interactive effects of plant biodiversity on element cycling and trophic interactions. The results show that environmental variables hierarchically shape AMF communities and that the sequence type spectrum is strongly affected by previous land use and disturbance, which appears to favor disturbance-tolerant members of the genus Glomus. The AMF species richness of disturbance-associated communities can be largely explained by richness of plant species and plant functional groups, while plant productivity and soil parameters appear to have only weak effects on the AMF community. PMID:20418424

  5. Switching Characteristics of Ferroelectric Transistor Inverters

    NASA Technical Reports Server (NTRS)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  6. MR characteristics of iophendylate (Pantopaque).

    PubMed

    Hackney, D B; Grossman, R I; Zimmerman, R A; Joseph, P M; Goldberg, H I; Bilaniuk, L T

    1986-01-01

    Although iophendylate (Pantopaque) has been largely replaced by water soluble agents for myelography, retained intracranial or intraspinal Pantopaque remains a common occurrence. Pantopaque has signal characteristics similar to fat with both short T1 and T2 relaxation times. In vitro measurements revealed T1 = 170 ms and T2 = 27 ms. Spine radiography is recommended in patients with a history of previous myelography and magnetic resonance abnormalities similar to fat. PMID:3486195

  7. Timing and characteristics of Late Pleistocene and Holocene wetter periods in the Eastern Desert and Sinai of Egypt, based on 14C dating and stable isotope analysis of spring tufa deposits

    NASA Astrophysics Data System (ADS)

    Hamdan, Mohamed A.; Brook, George A.

    2015-12-01

    There is very little dated evidence on wet periods in the Eastern Desert and Sinai Peninsula of Egypt during the Late Pleistocene and Holocene. To obtain such information, we have studied the petrography, isotope geochemistry and AMS radiocarbon ages of mostly relict tufas deposited by springs draining perched ground water bodies in metamorphic and volcanic rocks. The tufas unconformably overly Precambrian basic igneous rocks (basalt, diabase and gabbro). As the ages of tufa carbonate are frequently older than the true ages of the deposits because of the incorporation of old, 14C-dead carbon, we have dated both the carbonate matrix and insoluble organic material of the tufas. These ages show that the tufas were largely formed during two broad time periods, the most recent from 12,058 to 6678 cal yr BP (African Humid Period), and the other from ˜31,200-22,500 cal yr BP, with preferential growth during the coldest times of this period namely during Heinrich Events 2 and 3 (H2 and H3) and the Last Glacial Maximum (LGM). The time span between 19,000-9000 cal yr BP, including the YD and H1, appears to have been relatively more arid than the earlier LGM or H2 periods or the later Holocene. The Late Pleistocene tufas are depleted in 18O relative to the Holocene tufas and were deposited at a lower temperature (˜14.0°-20.8 °C vs. 18.4°-23.4 °C). We believe that the Holocene tufas in the Sinai were formed by rainfall from the Mediterranean and those in the southern part of the Eastern Desert by African monsoon rainfall derived from the Red Sea-Gulf of Aden and Indian Ocean. In contrast, the moisture that fed the Late Pleistocene tufas, which are depleted in 18O relative to Holocene deposits, and progressively depleted from north to south, was probably brought by the Westerlies from the Atlantic-Mediterranean Sea when the Westerly circulation was pushed southwards during the coldest periods of the Late Pleistocene. Periods of tufa deposition correlate with major documented paleoclimatic events in North Africa during the late Pleistocene and Holocene; such as the Nile floods, high sea level and the formation of sapropels in the Mediterranean.

  8. Using vein fabric and fluid inclusion characteristics as an integrated proxy to constrain the relative timing of non cross-cutting, syn- to late-orogenic quartz vein generations

    NASA Astrophysics Data System (ADS)

    Jacques, Dominique; Muchez, Philippe; Sintubin, Manuel

    2014-05-01

    Research on ancient fluid systems mainly focuses on veins, because they offer the opportunity to combine macro- and microstructural data with geochemical data to gain insight into the P-T-X conditions present during veining. By applying such an integrated petrographic and microthermometric methodology to syn- to late-orogenic quartz veins in the Palaeozoic High-Ardenne slate belt (Belgium), we were able to define the relative timing and related P-T-X conditions of different quartz vein generations, despite of the absence of any mutual cross-cutting relationships in the field (Jacques et al., 2014). The different quartz vein generations represent the meso-scale brittle accommodation during fold initiation, amplification and locking. The presence of free polycrystal growth in cavities at a midcrustal depth, and fluid-assisted brecciation indicate that veining occurred under overpressured fluid conditions during the orogeny. Significant differences in crystal-plastic deformation microstructures and P-T trapping conditions indicate that the different processes accommodating folding occurred in a progressive manner along a retrograde deformation path. While vein quartz in an extrados vein and in the peripheral part of a lenticular, fault-accommodating vein shows moderate crystal-plastic deformation (e.g. bulging recrystallisation, deformation lamellae, shear bands), crystal-plastic deformation is relatively absent in the vein quartz of a saddle reef and the core of the lenticular vein (i.e. no to minor undulose extinction). Successive veining occurred from peak metamorphic conditions (ca. 300 ° C and 190 MPa), measured in the extrados vein, to lower P-T conditions in the periphery of the lenticular vein (ca. 275 ° C and 180 MPa), the late-orogenic saddle reef (ca. 245 ° C and 160 MPa) and the core of the lenticular vein (ca. 220 ° C and 150 MPa). The relative timing and accompanying decrease in P-T conditions of the different quartz vein generations reflect the gradual exhumation of the slate belt from ca. 7.5 to 6 km depth along a retrograde deformation path. A comparison of these results with a former study of syn- to late-orogenic calcite veins at the Variscan front zone (Kenis et al., 2000), indicates that exhumation processes throughout the Rhenohercynian fold-and-thrust belt were diachronous. While exhumation and related quartz veining in the High-Ardenne slate belt occurred during the Sudetic stage of the Variscan orogeny (ca. 325-310 Ma), the exhumation and related calcite veining at the Variscan front zone occurred during the Asturian stage of the Variscan orogeny (ca. 300 Ma). With this study we demonstrate that a relative timing for different vein generations, lacking any cross-cutting relationship, can still be attained through an integration of petrographic and microthermometric arguments. Moreover, this particular approach, enables to further delineate the P-T history of an orogenic system from its pre-, to its syn-, late- and finally postkinematic stages. References Jacques, D., Derez, T., Muchez, P., Sintubin, M., 2014. Syn- to late-orogenic quartz veins marking a retrograde deformation path in a slate belt: Examples from the High-Ardenne slate belt (Belgium). Journal of Structural Geology, 58, 43-58. Kenis, I., Muchez, P., Sintubin, M., Mansy, J.-L., Lacquement, F., 2000. The use of a combined structural, stable isotope and fluid inclusion study to constrain the kinematic history at the northern Variscan front zone (Bettrechies, northern France). Journal of Structural Geology, 22, 589-602.

  9. Fetal Alcohol Syndrome: Characteristics, Prevention, Treatment and Long Term Outlook.

    ERIC Educational Resources Information Center

    Seward, Cynthia A.; Barber, William H.

    1991-01-01

    This article discusses fetal alcohol syndrome (FAS) including causes, common characteristics, secondary characteristics, prevention, and treatment. Economic implications are noted which suggest that treatment costs are 100 times the cost of prevention programs. (DB)

  10. Experimental investigation of the effect of polymer matrices on polymer fibre optic oxygen sensors and their time response characteristics using a vacuum testing chamber and a liquid flow apparatus

    PubMed Central

    Chen, Rongsheng; Formenti, Federico; McPeak, Hanne; Obeid, Andrew N.; Hahn, Clive; Farmery, Andrew

    2016-01-01

    Very fast sensors that are able to track rapid changes in oxygen partial pressure (PO2) in the gas and liquid phases are increasingly required in scientific research – particularly in the life sciences. Recent interest in monitoring very fast changes in the PO2 of arterial blood in some respiratory failure conditions is one such example. Previous attempts to design fast intravascular electrochemical oxygen sensors for use in physiology and medicine have failed to meet the criteria that are now required in modern investigations. However, miniature photonic devices are capable of meeting this need. In this article, we present an inexpensive polymer type fibre-optic, oxygen sensor that is two orders of magnitude faster than conventional electrochemical oxygen sensors. It is constructed with biologically inert polymer materials and is both sufficiently small and robust for direct insertion in to a human artery. The sensors were tested and evaluated in both a gas testing chamber and in a flowing liquid test system. The results showed a very fast T90 response time, typically circa 20 ms when tested in the gas phase, and circa 100 ms in flowing liquid. PMID:26726286

  11. Characteristics of Successful Entrepreneurs.

    ERIC Educational Resources Information Center

    McClelland, David C.

    1987-01-01

    Comparison of characteristics of 12 average and 12 superior small business people in three developing nations (India, Malawi, and Ecuador) found proactive qualities such as initiative and assertiveness, achievement orientation, and commitment to others characteristic of successful entrepreneurs. Other expected qualities (self-confidence,

  12. Characteristics of Successful Entrepreneurs.

    ERIC Educational Resources Information Center

    McClelland, David C.

    1987-01-01

    Comparison of characteristics of 12 average and 12 superior small business people in three developing nations (India, Malawi, and Ecuador) found proactive qualities such as initiative and assertiveness, achievement orientation, and commitment to others characteristic of successful entrepreneurs. Other expected qualities (self-confidence,…

  13. Petrophysical Characteristics of Impaktites

    NASA Astrophysics Data System (ADS)

    Mayr, S. I.; Popov, Yu.

    2015-09-01

    We give examples of petrophysical characteristics of Impactites. We differ between impact breccia and impact melt rocks, and shocked & displaced target rocks. We use our datasets obtained from Puchezh-Katunki, Ries, Chicxulub and Chesapeake.

  14. AEROSOL CHARACTERISTICS AND VISIBILITY

    EPA Science Inventory

    This report summarizes progress in measuring the optical properties of aerosols and in relating aerosol characteristics to visibility reduction made in the author's laboratory during the period 1965-1971. An instrument, the integrating nephelometer, which measures the scattering ...

  15. Housing characteristics 1993

    SciTech Connect

    1995-06-01

    This report, Housing Characteristics 1993, presents statistics about the energy-related characteristics of US households. These data were collected in the 1993 Residential Energy Consumption Survey (RECS) -- the ninth in a series of nationwide energy consumption surveys conducted since 1978 by the Energy Information Administration of the US Department of Energy. Over 7 thousand households were surveyed, representing 97 million households nationwide. A second report, to be released in late 1995, will present statistics on residential energy consumption and expenditures.

  16. Onboard Navigation Systems Characteristics

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The space shuttle onboard navigation systems characteristics are described. A standard source of equations and numerical data for use in error analyses and mission simulations related to space shuttle development is reported. The sensor characteristics described are used for shuttle onboard navigation performance assessment. The use of complete models in the studies depend on the analyses to be performed, the capabilities of the computer programs, and the availability of computer resources.

  17. The First Time

    ERIC Educational Resources Information Center

    Black, Beth

    2011-01-01

    In this article, the author narrates her experience of meeting a Montessori kid for the first time and shares the characteristics she observed in Montessori students. The author was working as director of academic resources in university housing at the University of Wisconsin-Madison and met Jason, a pre-med sophomore who was the resident…

  18. Flowfield-Dependent Mixed Explicit-Implicit (FDMEL) Algorithm for Computational Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Garcia, S. M.; Chung, T. J.

    1997-01-01

    Despite significant achievements in computational fluid dynamics, there still remain many fluid flow phenomena not well understood. For example, the prediction of temperature distributions is inaccurate when temperature gradients are high, particularly in shock wave turbulent boundary layer interactions close to the wall. Complexities of fluid flow phenomena include transition to turbulence, relaminarization separated flows, transition between viscous and inviscid incompressible and compressible flows, among others, in all speed regimes. The purpose of this paper is to introduce a new approach, called the Flowfield-Dependent Mixed Explicit-Implicit (FDMEI) method, in an attempt to resolve these difficult issues in Computational Fluid Dynamics (CFD). In this process, a total of six implicitness parameters characteristic of the current flowfield are introduced. They are calculated from the current flowfield or changes of Mach numbers, Reynolds numbers, Peclet numbers, and Damkoehler numbers (if reacting) at each nodal point and time step. This implies that every nodal point or element is provided with different or unique numerical scheme according to their current flowfield situations, whether compressible, incompressible, viscous, inviscid, laminar, turbulent, reacting, or nonreacting. In this procedure, discontinuities or fluctuations of an variables between adjacent nodal points are determined accurately. If these implicitness parameters are fixed to certain numbers instead of being calculated from the flowfield information, then practically all currently available schemes of finite differences or finite elements arise as special cases. Some benchmark problems to be presented in this paper will show the validity, accuracy, and efficiency of the proposed methodology.

  19. Characteristic time for halo current growth and rotation

    NASA Astrophysics Data System (ADS)

    Boozer, Allen

    2015-11-01

    Halo currents, Ih, flow in part through plasma on open magnetic lines and in part through the walls. A halo current has the same function as the wall current of a resistive wall mode and arises when a kink cannot be wall stabilized. When flowing in the plasma, the halo current can produce no forces, so j->h = (j∥ / B) B-> with B-> . ∇ -> j∥ / B = 0 . To avoid too strong a coupling to stable kinks, the wall interception must be of sufficient toroidal extent, which implies the width of the halo current channel Δh aIh /Ip , where aIh /Ip is the amplitude of the kink, a is the minor radius, and Ip is the plasma current. The equation for the growth of the halo current is dIh / dt =Ip /τg , where τg (μ0 /ηh) (a2 / 4) /seff and seff is a dimensionless stability coefficient. The rocket effect of the plasma flowing out of the two ends of the magnetic field lines in the halo can set the magnetic perturbation into toroidal rotation at a Mach number, Mh, comparable to unity. The rotation period is τr = (2 πR0 /Cs) /Mh , where R0 is the major radius and Cs =√{ (Te +Ti) /mi } is the speed of sound. NSTX results appear consistent for seff 0 . 5 , Mh 1 , and Te , i = 10 eV. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences under Award Number De-FG02-03ER54696.

  20. Takeoff characteristics of turbofan engines

    SciTech Connect

    Suh, Y.B. )

    1990-05-01

    The present derivation of reliable formulas for the takeoff characteristics of turbofan-powered aircraft, encompassing ground-roll distance and time, fuel consumption, etc, incorporates ground effect-induced drag reduction. This drag reduction factor is varied according to type of aircraft; the turbofans in question may be of high-bypass transport-aircraft type or of low bypass and afterburner-employing configuration, as is typically the case in military aircraft. It is shown that bypass ratio variations have little influence on takeoff ground-rolling distance.

  1. Characteristic ratio assignment in fractional order systems.

    PubMed

    Tabatabaei, Mohammad; Haeri, Mohammad

    2010-10-01

    In this paper the characteristic ratios and generalized time constant are defined for all-pole commensurate fractional order systems. The sufficient condition for stability of these systems in terms of their characteristic ratios is obtained. Also an analytical approach for characteristic ratio assignment (CRA) to have a non-overshooting fast closed loop step response is introduced. The proposed CRA method is then employed to design a fractional order controller. Computer simulation results are presented to illustrate the performance of the CRA based designed fractional order controllers. PMID:20619834

  2. Commercial Buildings Characteristics, 1992

    SciTech Connect

    Not Available

    1994-04-29

    Commercial Buildings Characteristics 1992 presents statistics about the number, type, and size of commercial buildings in the United States as well as their energy-related characteristics. These data are collected in the Commercial Buildings Energy Consumption Survey (CBECS), a national survey of buildings in the commercial sector. The 1992 CBECS is the fifth in a series conducted since 1979 by the Energy Information Administration. Approximately 6,600 commercial buildings were surveyed, representing the characteristics and energy consumption of 4.8 million commercial buildings and 67.9 billion square feet of commercial floorspace nationwide. Overall, the amount of commercial floorspace in the United States increased an average of 2.4 percent annually between 1989 and 1992, while the number of commercial buildings increased an average of 2.0 percent annually.

  3. Flushing Time

    EPA Science Inventory

    The flushing time of an estuary is generally defined as the turnover time of fresh water in the estuary, that is, the time required to replace the fresh water contained in the estuary with freshwater inflow. Thus, the flushing time of an estuary is the ratio of the volume of fres...

  4. Reinventing Time

    ERIC Educational Resources Information Center

    Technology Teacher, 2004

    2004-01-01

    What do planet Earth, a swinging pendulum, a quartz crystal, and a Cesium atom have in common? They have all been used by humans to measure time. They represent humanity's progress through time in measuring time itself. But what is it, really, that humans set out to measure? Before time could be measured, somebody had to decide what to actually…

  5. VARIABLE TIME DELAY MEANS

    DOEpatents

    Clemensen, R.E.

    1959-11-01

    An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

  6. Chua's Time

    NASA Astrophysics Data System (ADS)

    Buscarino, Arturo; Fortuna, Luigi; Frasca, Mattia

    2013-01-01

    We discuss the relationship between the idea of time of the philosopher Bergson and the concept of time recurrence in chaotic systems. By taking into account the Chua's circuit, we saw that the "Chua's time", i.e., the average recurrence time of trajectories in the Chua's circuit, is able to qualitatively represent the features of the Bergon's time. Numerical and experimental results are presented.

  7. Gender and Learner Characteristics

    ERIC Educational Resources Information Center

    Hindal, Huda; Reid, Norman; Whitehead, Rex

    2013-01-01

    It is well established that girls and boys perform differently in traditional examinations in most countries. This study looks at a sample of 754 school students in Kuwait (aged about 13) and explores how boys and girls differ in the performance in a range of tests related to learner characteristics. The fundamental question is how boys and girls…

  8. Metering Characteristics of Carburetors

    NASA Technical Reports Server (NTRS)

    Tice, Percival S; Dickinson, H C

    1919-01-01

    Report presents the results of an extensive experimental investigation of the performance of different types of carburetors as effecting the maintenance under all conditions of correct ratio between the weights of fuel and air. It also gives a description of the Bureau of Standards carburetor test plant, test equipment and measuring instruments used to determine the metering characteristics of carburetors.

  9. Characteristics of Teacher Leaders.

    ERIC Educational Resources Information Center

    Brownlee, Geraldine D.

    1979-01-01

    Presented is a research study which investigated teacher leadership characteristics, which are described. It was concluded that teachers have leadership roles in the school, outside the classroom; teacher leaders are recognizable by other teachers; teacher leaders are identifiable by principals; teachers and principals agree on the identity of…

  10. Characteristics of Anchor Tests.

    ERIC Educational Resources Information Center

    Chang, S. Tai; Bashaw, W. L.

    The purpose of this study was twofold: to investigate to what extent characteristics of anchor tests may affect precision of item calibration, and to estimate to what extent precision of item calibration may be affected by removal of persons whose response patterns deviate from those normally expected from the Rasch one-parameter logistic model.…

  11. Personality Characteristics of Engineers

    ERIC Educational Resources Information Center

    van der Molen, Henk T.; Schmidt, Henk G.; Kruisman, Gerard

    2007-01-01

    The objective of the current study was to investigate the personality characteristics of a group of engineers with a variety of years of experience. It was executed to remedy shortcomings of the literature concerning this issue and to produce suggestions for a postgraduate training programme for engineers. A total of 103 engineers were tested with…

  12. Attractive characteristics of mirrors

    SciTech Connect

    Post, R.F.; Ryutov, D.D.

    1994-12-15

    A summary of the attractive characteristics of mirror devices is presented. Recent progress in development of axisymmetric mirror devices is described. Potentialities of mirrors as a basis for D{sup 3}He fusion power generators and high-flux neutron sources for fusion material tests are discussed.

  13. Attractive characteristics of mirrors

    NASA Astrophysics Data System (ADS)

    Post, R. F.; Ryutov, D. D.

    1994-12-01

    A summary of the attractive characteristics of mirror devices is presented. Recent progress in development of axisymmetric mirror devices is described. Potentialities of mirrors as a basis for D(3)He fusion power generators and high-flux neutron sources for fusion material tests are discussed.

  14. Characteristics of Hypermedia Presentations.

    ERIC Educational Resources Information Center

    Lewis, Wiley B.; Jansen, Duane G.

    This paper addresses those characteristics of effective and efficient hypermedia presentations that are important for consideration by educators in developing and/or selecting such presentations. Definitions of hypertext, hypermedia, and multimedia are provided, and the relationships among these terms are described. Four other terms useful to…

  15. Personality Characteristics of Engineers

    ERIC Educational Resources Information Center

    van der Molen, Henk T.; Schmidt, Henk G.; Kruisman, Gerard

    2007-01-01

    The objective of the current study was to investigate the personality characteristics of a group of engineers with a variety of years of experience. It was executed to remedy shortcomings of the literature concerning this issue and to produce suggestions for a postgraduate training programme for engineers. A total of 103 engineers were tested with

  16. Time out

    MedlinePlus

    ... punishing children may help them learn that physical violence or inflicting physical pain does NOT bring desired results. Children learn to avoid time out by stopping the behaviors that have caused time outs, or warnings of ...

  17. Bleeding time

    MedlinePlus

    Bleeding time is a medical test that measures how fast small blood vessels in the skin stop bleeding. ... until the bleeding stops. The provider records the time it takes for the cuts to stop bleeding.

  18. Managing time.

    PubMed

    Wachs, J E

    1993-06-01

    Managing time puts the occupational health nurse manager in control of health services and personal goals. Articulating those goals and appropriately delegating some of the outcomes needed to meet those goals should result in accomplishing the goals in less time. Strategies to control time expenditures on a daily basis include developing a "to do" list, avoiding procrastination, time wasters, and paper shuffling, creating an environment conducive to work, and rewarding self and staff for a job well done. PMID:8512614

  19. Time Honoured

    ERIC Educational Resources Information Center

    Campbell, Mora; Timmerman, Peter

    2007-01-01

    The vast majority of literature and practices in environmental education focuses on places and spaces. Little attention has been paid to time and temporalities as elements of environments, and the ways in which how we experience time affects our experience of place. This paper is an examination of the ways in which reflection on time can be…

  20. Characteristics of healthcare wastes

    SciTech Connect

    Diaz, L.F. Eggerth, L.L.; Enkhtsetseg, Sh.; Savage, G.M.

    2008-07-01

    A comprehensive understanding of the quantities and characteristics of the material that needs to be managed is one of the most basic steps in the development of a plan for solid waste management. In this case, the material under consideration is the solid waste generated in healthcare facilities, also known as healthcare waste. Unfortunately, limited reliable information is available in the open literature on the quantities and characteristics of the various types of wastes that are generated in healthcare facilities. Thus, sound management of these wastes, particularly in developing countries, often is problematic. This article provides information on the quantities and properties of healthcare wastes in various types of facilities located in developing countries, as well as in some industrialized countries. Most of the information has been obtained from the open literature, although some information has been collected by the authors and from reports available to the authors. Only data collected within approximately the last 15 years and using prescribed methodologies are presented. The range of hospital waste generation (both infectious and mixed solid waste fractions) varies from 0.016 to 3.23 kg/bed-day. The relatively wide variation is due to the fact that some of the facilities surveyed in Ulaanbaatar include out-patient services and district health clinics; these facilities essentially provide very basic services and thus the quantities of waste generated are relatively small. On the other hand, the reported amount of infectious (clinical, yellow bag) waste varied from 0.01 to 0.65 kg/bed-day. The characteristics of the components of healthcare wastes, such as the bulk density and the calorific value, have substantial variability. This literature review and the associated attempt at a comparative analysis point to the need for worldwide consensus on the terms and characteristics that describe wastes from healthcare facilities. Such a consensus would greatly facilitate comparative analyses among different facilities, studies and countries.

  1. Advanced turboprop vibratory characteristics

    NASA Technical Reports Server (NTRS)

    Srinivasan, A. V.; Fulton, G. B.

    1984-01-01

    The assembly of SR5 advanced turboprop blades to develop a structural dynamic data base for swept props is reported. Steady state blade deformation under centrifugal loading and vibratory characteristics of the rotor assembly were measured. Vibration was induced through a system of piezoelectric crystals attached to the blades. Data reduction procedures are used to provide deformation, mode shape, and frequencies of the assembly at predetermined speeds.

  2. Time Out for Measuring Time.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1983-01-01

    The ability to measure time means being able to arrange events in logical sequences, predict which kinds of events take longer than others, and understand different divisions of time. Teaching methods and class activities that will help children develop skills and concepts concerning time usage are presented. (PP)

  3. Mexican-American Adolescents' Gender-Typed Characteristics: The Role of Sibling and Friend Characteristics.

    PubMed

    Perez-Brena, Norma J; Wheeler, Lorey A; Updegraff, Kimberly A; Schaefer, David R

    2015-07-01

    This study examined the role of sibling and friend characteristics in Mexican-American youth's gender-typed characteristics (i.e., attitudes, interests, and leisure activities) in early versus middle adolescence using a sibling design. Mexican-American 7th graders (M = 12.51 years; SD = .58) and their older siblings (M = 15.48 years; SD = 1.57) from 246 families participated in home interviews and a series of seven nightly phone calls. Results revealed that younger/early adolescent siblings reported more traditional gender role attitudes than their older/middle adolescent siblings and older brothers were more traditional in their attitudes than older sisters. When comparing siblings' gender-typed interests and leisure activities, boys reported more masculine orientations than girls and girls reported more feminine orientations than boys. Older brothers' gender-typed characteristics were associated with the amount of time spent with and gender characteristics of their friendship group, but for younger brothers, sibling characteristics were associated with their gender-typed characteristics. In contrast, both sibling and friendship characteristics were significantly associated with older and younger sisters' gender-typed characteristics. The discussion addressed the different correlates of older and younger sisters' and brothers' gender-typed characteristics. PMID:25539774

  4. TIMING APPARATUS

    DOEpatents

    Bennett, A.E.; Geisow, J.C.H.

    1956-04-17

    The timing device comprises an escapement wheel and pallet, a spring drive to rotate the escapement wheel to a zero position, means to wind the pretensioned spring proportional to the desired signal time, and a cam mechanism to control an electrical signal switch by energizing the switch when the spring has been wound to the desired position, and deenergizing it when it reaches the zero position. This device produces an accurately timed signal variably witain the control of the operator.

  5. Geologic time

    USGS Publications Warehouse

    Newman, William L.

    2000-01-01

    The Earth is very old 4 1/2 billion years or more according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

  6. Optical freedom degrees and information characteristics of light information systems

    NASA Astrophysics Data System (ADS)

    Gurevich, Boris S.; Gurevich, Simon B.; Jumaliev, Kubanychbek

    2008-05-01

    Light information devices were created a long time before the information theory was developed, and the features of these devices were described by the common optical characteristics. However, these characteristics look insufficient for these devices information abilities definition, and the need for specific information characteristics has become apparant. Along with that, the common methods for optical characteristics estimation must be applied for the definition of information characteristics. It has been necessary to compare some optical characteristics (input signal value expressed in amplitude and phase, resolving power, signal distribution by light wavelengths or color components, by polarization plane position, and by time intervals) with the information ones. In order to come to information characteristics, it was necessary to perform optical signal and object (and image) light field digitization. In this work we discuss and compare different methdos of the signal and image light field division into different componenets (freedom degrees): determined, statistical, and system-based.

  7. Adult Learner Characteristics and Instructional Objectives.

    ERIC Educational Resources Information Center

    Etter, David Campbell George

    Using 40 male and 40 female part time learners with an average age of 36.6, this program planning study explored relationships between selected learner characteristics and behaviorally stated cognitive instructional objectives (IOs). Variables included age, sex, socioeconomic status, verbal ability, and a measure of learners' goals or learning…

  8. Student Characteristics and Enrollment Trends, Fall 2000.

    ERIC Educational Resources Information Center

    Cartnal, Ryan

    Cuesta College's (California) Five-year Student Characteristics and Enrollment Trends (1996-2000) report provides tables and figures that show student demography and enrollment status. Tables 1 through 11 present data for the entire college. Table 1 shows that enrollment at Cuesta College continues to increase and is now at an all-time high of…

  9. Employee Characteristics and Salary Statistics. Fall 1970.

    ERIC Educational Resources Information Center

    State Univ. of New York, Albany. Central Staff Office of Institutional Research.

    This document presents data concerning employee characteristics and salary statistics for the faculty at the various campuses of the State University of New York in Fall 1970. The data are presented in tables by campus, full- and part-time status, and by rank of the instructional staff. The subject field and earned degrees of the faculty are…

  10. Fourteen characteristics of effective leaders in dentistry.

    PubMed

    Christensen, Gordon J

    2004-01-01

    Leadership can be learned, especially through careful observation of effective leaders. Fourteen characteristics of effective leaders in the dental office and in organized dentistry are discussed. These include: positive mental attitude, faith, goals in life, organization, time management, interdependency and synergy, consistency, communication, self-renewal, empathy and humility, creativity, personal responsibility and drive, ability to say no, and charisma. PMID:15948488

  11. Time Management

    ERIC Educational Resources Information Center

    Stoilov, Todor, Ed.

    2012-01-01

    The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as

  12. Managing Time.

    ERIC Educational Resources Information Center

    Murphy, Linda; Della Corte, Suzanne

    1991-01-01

    This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household…

  13. Time Management

    ERIC Educational Resources Information Center

    Stoilov, Todor, Ed.

    2012-01-01

    The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as…

  14. Managing Time.

    ERIC Educational Resources Information Center

    Murphy, Linda; Della Corte, Suzanne

    1991-01-01

    This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household

  15. Turnover Time

    EPA Science Inventory

    Ecosystems contain energy and materials such as carbon, nitrogen, phosphorus, and water, and are open to their flow-through. Turnover time refers to the amount of time required for replacement by flow-through of the energy or substance of interest contained in the system, and is ...

  16. The Variance Reaction Time Model

    ERIC Educational Resources Information Center

    Sikstrom, Sverker

    2004-01-01

    The variance reaction time model (VRTM) is proposed to account for various recognition data on reaction time, the mirror effect, receiver-operating-characteristic (ROC) curves, etc. The model is based on simple and plausible assumptions within a neural network: VRTM is a two layer neural network where one layer represents items and one layer…

  17. Magnesium battery disposal characteristics

    NASA Astrophysics Data System (ADS)

    Soffer, Louis; Atwater, Terrill

    1994-12-01

    This study assesses the disposal characteristics of U.S. Army procured military magnesium batteries under current Resource Conservation and Recovery Act (RCRA) hazardous waste identification regulations administered by the U.S. Environmental Protection Agency. Magnesium batteries were tested at 100, 50, 10 and 0 percent remaining state of charge. Present findings indicate that magnesium batteries with less than 50 percent remaining charge do not exceed the federal regulatory limit of 5.0 mg/L for chromium. All other RCRA contaminates were below regulatory limits at all levels of remaining charge. Assay methods, findings, disposal requirements and design implications are discussed.

  18. Part-time Work in International Perspective.

    ERIC Educational Resources Information Center

    Thurman, Joseph E.; Trah, Gabriele

    1990-01-01

    Examines the reasons for part-time work and characteristics of part-time workers, legislative protection, national incentives to increase access to part-time jobs, and forms of part-time work. Explores arguments for and against part-time employment. (SK)

  19. Time ephemeris

    NASA Astrophysics Data System (ADS)

    Fukushima, T.

    1995-02-01

    The location-independent part of barycentric coordinate time and geocentric coordinate time (TCB-TCG), the difference between the two new time scales adopted by the IAU, was integrated numerically for three JPL planetary/lunar ephemerides; DE102, DE200, and DE245. The differences among these three integrations were mostly explained by the difference in the adopted constants of the ephemerides. It was shown that the post-Newtonian correction and the perturbation by asteroids are negligible except for the mean rate, LC. The comparison of these numerical integrations with the analytical formulas of Hirayama et al. (1987) and Fairhead & Bretagnon (1990) as well as their extended versions lead to the best estimate of LC as 1.480 826 845 7 x 10-8 + or - 1.0 x 10-17. Combining this with the recent value of the geoid potential in Bursa et al. (1992), we estimate the value of LB, the scale difference between TCB and terrestrial time (TT), as 1.550 519 748 x 10-8 + or - 4 x 10-17. This will be useful in converting the numerical values of some astronomical constants determined in the old IAU time scale barycentric dynamic time (TDB) to those in TCB. Also the paper will be useful when converting between TCB and TDB, i.e. the time scales themselves.

  20. Characteristics of Microbursts

    NASA Astrophysics Data System (ADS)

    Crew, A. B.; Spence, H. E.

    2012-12-01

    The dynamics of the Earth's radiation belts are governed by the interplay between the various source and loss terms. Electron microbursts represent a particular form of electron loss through precipitation to the atmosphere. The total loss from each individual microburst is relatively small; however microbursts are often seen in very large numbers. Accordingly, the total loss due to electron microbursts is a still unresolved question. Taking advantage of the length and continuity of microburst observations from SAMPEX, I will present analysis of the characteristics of ~685,000 electron (> 1 MeV) microburst events. Examining the event frequency, intensity, and duration I will show that microbursts are typically seen on the dawnside from L of approximately 4 to 7, with event frequencies that track with geomagnetic indices such as AE. Individual microburst intensities typically follow power-law like distributions and peak in power close to dawn, and typical event durations are ~100ms. Using the event characteristics and an epoch analysis of over 200 storm intervals from this period we examine the differences in microburst precipitation across different storms as well as provide estimates and constraints on the total effectiveness of microburst precipitation as a form of radiation belt loss. We hope to use the estimates to contextualize results from the upcoming RBSP mission.

  1. Discovering salient characteristics of authors of artworks

    NASA Astrophysics Data System (ADS)

    Bajcsy, Peter; Moslemi, Maryam

    2010-02-01

    We addressed the problem of finding salient characteristics of artists from two-dimensional (2D) images of historical artifacts. Given a set of 2D images of historical artifacts by known authors, we discovered what salient characteristics made an artist different from others, and then enabled statistical learning about individual and collective authorship. The objective of this effort was to learn what would be unique about the style of each artist, and to provide the quantitative results about salient characteristic. We accomplished this by exploring a large search space of low level image descriptors. The motivation behind our framework was to assist humanists in discovering salient characteristics by automated exploration of the key image descriptors. By employing our framework we had not only saved time of art historians but also provided quantitative measures for incorporating their personal judgments and bridging the semantic gap in image understanding. We applied the framework implementation to the face illustrations in Froissart's Chronicles drawn by two anonymous authors. We reported the salient characteristics to be (HSV, histogram, k-nearest neighbor) among the 55 triples considered with 5-fold validations. These low level characteristics were confirmed by the experts to correspond semantically to the face skin colors.

  2. Thrombin Time

    MedlinePlus

    ... monitor unfractionated heparin therapy and to detect heparin contamination in a blood sample. While it is still ... thrombin time may sometimes be ordered when heparin contamination of a sample is suspected or when a ...

  3. Time outs

    MedlinePlus

    ... Time-out technique for discipline. Children's Health Network web site. http://www.childrenshealthnetwork.org/CRS/CRS/pa_ ... a break from negative behavior. Massachusetts Medical Society web site. http://www.massmed.org/patient-care/health- ...

  4. About time

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1990-01-01

    Time has historically been a measure of progress of recurrent physical processes. Coordination of future actions, prediction of future events, and assigning order to events are three practical reasons for implementing clocks and signalling mechanisms. In large networks of computers, these needs lead to the problem of synchronizing the clocks throughout the network. Recent methods allow this to be done in large networks with precision around 1 millisecond despite mean message exchange times near 5 milliseconds. These methods are discussed.

  5. Fibre Optic Sensors for Selected Wastewater Characteristics

    PubMed Central

    Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

    2013-01-01

    Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising. PMID:23881131

  6. Wafer characteristics via reflectometry

    DOEpatents

    Sopori, Bhushan L.

    2010-10-19

    Various exemplary methods (800, 900, 1000, 1100) are directed to determining wafer thickness and/or wafer surface characteristics. An exemplary method (900) includes measuring reflectance of a wafer and comparing the measured reflectance to a calculated reflectance or a reflectance stored in a database. Another exemplary method (800) includes positioning a wafer on a reflecting support to extend a reflectance range. An exemplary device (200) has an input (210), analysis modules (222-228) and optionally a database (230). Various exemplary reflectometer chambers (1300, 1400) include radiation sources positioned at a first altitudinal angle (1308, 1408) and at a second altitudinal angle (1312, 1412). An exemplary method includes selecting radiation sources positioned at various altitudinal angles. An exemplary element (1650, 1850) includes a first aperture (1654, 1854) and a second aperture (1658, 1858) that can transmit reflected radiation to a fiber and an imager, respectfully.

  7. Real time automated inspection

    DOEpatents

    Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

    1985-05-21

    A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

  8. Real time automated inspection

    DOEpatents

    Fant, Karl M.; Fundakowski, Richard A.; Levitt, Tod S.; Overland, John E.; Suresh, Bindinganavle R.; Ulrich, Franz W.

    1985-01-01

    A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

  9. Three Characteristics of Effective Teachers

    ERIC Educational Resources Information Center

    Steele, Natalie A.

    2010-01-01

    This article discusses three characteristics that are often associated with successful music educators. The three characteristics discussed include nonverbal communication, teacher self-efficacy, and servant leadership. Although there is no magical combination of characteristics that will produce an effective music teacher, these three attributes…

  10. Number Time

    ERIC Educational Resources Information Center

    Herrera, Terese A.

    2004-01-01

    This article features Number Time, a site developed by the British Broadcasting Corporation (BBC) for young mathematics learners, located at www.bbc.co.uk/schools/numbertime. The site uses interactive animation to help children in pre-K through grade 2 understand and practice number basics. Users will find online games, videos that tell number…

  11. Characteristics of Engineering Citations.

    ERIC Educational Resources Information Center

    Musser, Linda R.; Conkling, Thomas W.

    1996-01-01

    An analysis of 4,780 citations taken from scholarly journals in 16 areas of engineering showed that journals are cited 53% of the time; electrical engineering literature has the shortest "half-life"; and literature types age at different rates for engineering researchers, with books having the longest useful lives and conference papers the…

  12. Characteristics of Engineering Citations.

    ERIC Educational Resources Information Center

    Musser, Linda R.; Conkling, Thomas W.

    1996-01-01

    An analysis of 4,780 citations taken from scholarly journals in 16 areas of engineering showed that journals are cited 53% of the time; electrical engineering literature has the shortest "half-life"; and literature types age at different rates for engineering researchers, with books having the longest useful lives and conference papers the

  13. Laser beam characteristics of optical phased arrays

    NASA Astrophysics Data System (ADS)

    Soskind, Y. G.

    2015-05-01

    Optical phased arrays (OPAs) are being actively developed as the next generation of high power laser systems. The coherent combination of several laser beams in tiled OPA configurations, as well as their propagation through the atmosphere has been successfully demonstrated. At the same time, only limited discussions of OPA beam formation and propagation characteristics can be found in scientific literature. This paper is intended to fill the void by providing details about OPA beam formation phenomenon, as well as by presenting the key OPA beam characteristics. The influences of several OPA characteristics, including the aperture fill factor, the number of the individual beams comprising the OPA, and the shape of the individual beams on the formation and propagation of the laser radiation are presented. We also demonstrate the impact of OPA beam phase discontinuities, such as piston phase delays between the individual beams, on the resulting properties of the OPA beams.

  14. An Implicit Characteristic Based Method for Electromagnetics

    NASA Technical Reports Server (NTRS)

    Beggs, John H.; Briley, W. Roger

    2001-01-01

    An implicit characteristic-based approach for numerical solution of Maxwell's time-dependent curl equations in flux conservative form is introduced. This method combines a characteristic based finite difference spatial approximation with an implicit lower-upper approximate factorization (LU/AF) time integration scheme. This approach is advantageous for three-dimensional applications because the characteristic differencing enables a two-factor approximate factorization that retains its unconditional stability in three space dimensions, and it does not require solution of tridiagonal systems. Results are given both for a Fourier analysis of stability, damping and dispersion properties, and for one-dimensional model problems involving propagation and scattering for free space and dielectric materials using both uniform and nonuniform grids. The explicit Finite Difference Time Domain Method (FDTD) algorithm is used as a convenient reference algorithm for comparison. The one-dimensional results indicate that for low frequency problems on a highly resolved uniform or nonuniform grid, this LU/AF algorithm can produce accurate solutions at Courant numbers significantly greater than one, with a corresponding improvement in efficiency for simulating a given period of time. This approach appears promising for development of dispersion optimized LU/AF schemes for three dimensional applications.

  15. Pharmacologic characteristics of prulifloxacin.

    PubMed

    Matera, Maria Gabriella

    2006-01-01

    Prulifloxacin, the prodrug of ulifloxacin, is a broad-spectrum oral fluoroquinolone antibacterial agent. After absorption, prulifloxacin is metabolized by esterases to ulifloxacin. The drug has a long elimination half-life, allowing once-daily administration. In vitro, ulifloxacin is generally more active than other fluoroquinolones against a variety of clinical isolates of Gram-negative bacteria, including community and nosocomial isolates of Escherichia coli, Klebsiella spp., Proteus, Providencia and Morganella spp., Moraxella catarrhalis, Haemophilus spp., and Pseudomonas aeruginosa. Gram-positive organisms, including methicillin- or oxacillin-susceptible Staphylococcus aureus, Enterococcus spp. and Streptococcus pneumoniae, are susceptible to ulifloxacin. In well-designed clinical trials, prulifloxacin showed good clinical and bacteriological efficacy (similar to that of ciprofloxacin) and was generally well tolerated, demonstrating a similar tolerability profile to that of ciprofloxacin. In conclusion, the in vitro inhibitory and bactericidal activities exhibited by ulifloxacin and the favorable characteristics shown by its prodrug (prulifloxacin) in clinical trials, particularly indicate this drug for the treatment of lung and urinary infections. PMID:16360331

  16. Restructured Freedom configuration characteristics

    NASA Technical Reports Server (NTRS)

    Troutman, Patrick A.; Heck, Michael L.; Kumar, Renjith R.; Mazanek, Daniel D.

    1991-01-01

    In Jan. 1991, the LaRc SSFO performed an assessment of the configuration characteristics of the proposed pre-integrated Space Station Freedom (SSF) concept. Of particular concern was the relationship of solar array operation and orientation with respect to spacecraft controllability. For the man-tended configuration (MTC), it was determined that torque equilibrium attitude (TEA) seeking Control Moment Gyroscope (CMG) control laws could not always maintain attitude. The control problems occurred when the solar arrays were tracking the sun to produce full power while flying in an arrow or gravity gradient flight mode. The large solar array articulations that sometimes result from having the functions of the alpha and beta joints reversed on MTC induced large product of inertia changes that can invalidate the control system gains during an orbit. Several modified sun tracking techniques were evaluated with respect to producing a controllable configuration requiring no modifications to the CMG control algorithms. Another assessment involved the permanently manned configuration (PMC) which has a third asymmetric PV unit on one side of the transverse boom. Recommendations include constraining alpha rotations for MTC in the arrow and gravity gradient flight modes and perhaps developing new non-TEA seeking control laws. Recommendations for PMC include raising the operational altitude and moving to a symmetric configuration as soon as possible.

  17. Sensor Characteristics Reference Guide

    SciTech Connect

    Cree, Johnathan V.; Dansu, A.; Fuhr, P.; Lanzisera, Steven M.; McIntyre, T.; Muehleisen, Ralph T.; Starke, M.; Banerjee, Pranab; Kuruganti, T.; Castello, C.

    2013-04-01

    The Buildings Technologies Office (BTO), within the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), is initiating a new program in Sensor and Controls. The vision of this program is: • Buildings operating automatically and continuously at peak energy efficiency over their lifetimes and interoperating effectively with the electric power grid. • Buildings that are self-configuring, self-commissioning, self-learning, self-diagnosing, self-healing, and self-transacting to enable continuous peak performance. • Lower overall building operating costs and higher asset valuation. The overarching goal is to capture 30% energy savings by enhanced management of energy consuming assets and systems through development of cost-effective sensors and controls. One step in achieving this vision is the publication of this Sensor Characteristics Reference Guide. The purpose of the guide is to inform building owners and operators of the current status, capabilities, and limitations of sensor technologies. It is hoped that this guide will aid in the design and procurement process and result in successful implementation of building sensor and control systems. DOE will also use this guide to identify research priorities, develop future specifications for potential market adoption, and provide market clarity through unbiased information

  18. Teacher Retention: Teacher Characteristics, School Characteristics, Organizational Characteristics, and Teacher Efficacy

    ERIC Educational Resources Information Center

    Hughes, Gail D.

    2012-01-01

    The researcher utilized block-entry regression analysis to determine the impacts of teacher characteristics, school characteristics, organizational characteristics, and teacher efficacy on retention in teaching from 782 teacher surveys. Findings indicated that 83.50% of participants planned to teach until retirement. Wald statistics indicated that…

  19. Time-Distance Helioseismology

    NASA Technical Reports Server (NTRS)

    Duvall, Thomas L., Jr.

    2010-01-01

    Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

  20. The destruction of time in pathological narcissism.

    PubMed

    Kernberg, Otto F

    2008-04-01

    This paper describes the characteristics of subjective time (in contrast to objective time), with particular reference to a specific form of pathological experience and relation to the passage of time in patients with narcissistic personality undergoing psychoanalytic treatment. The clinical manifestations and technical approach to this pathology of time experience are outlined in the context of illustrative clinical vignettes. PMID:18405285