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1

Split, Characteristic Based Semi-Implicit Algorithm for Laminar/turbulent Incompressible Flows  

NASA Astrophysics Data System (ADS)

In an earlier paper, Zienkiewicz and Codina (Int. j. numer. methods fluids, 20, 869-885 (1995)) presented a general algorithm for the solution of both compressible and incompressible Navier-Stokes equations. The algorithm, based on operator splitting, permits arbitrary interpolation functions to be used while avoiding the Babska-Brezzi restriction. In addition, its characteristic based approach introduces a form of rational dissipation. Zienkiewicz et al. (Int. j. numer. methods fluids, 20, 887-913 (1995)) presented the application of this algorithm in its fully explicit form to various inviscid compressible flow problems. They also presented two incompressible flow problems solved by the fully explicit form, employing a pseudo compressibility. The present work deals with the application of the above algorithm it its semi-implicit form to some incompressible flow benchmark problems. Further, it extends the methodology to turbulent flows by employing both one, and two equation turbulence models. A comparison of results with earlier investigations is presented. Other issues addressed in this study include the effect of additional diffusion terms present in the scheme for both laminar and turbulent flow problems and some practical difficulties associated with local time stepping.

Zienkiewicz, O. C.; Sai, B. V. K. Satya; Morgan, K.; Codina, R.

1996-10-01

2

Laminar-Turbulent Transition in an Electromagnetically-Levitated Droplet  

NASA Technical Reports Server (NTRS)

During experiments on the MSL-1 (First Microgravity Science Laboratory) mission of the Space Shuttle (STS-83 and STS-94, April and July 1997), a droplet of palladium-silicon alloy was electromagnetically levitated for viscosity measurements. For the non-deforming droplet, the resultant MHD flow inside the drop can be inferred from motion of impurity particulates on the surface. In the experiments, subsequent to melting, Joule heating produces a continuous reduction of viscosity of the fluid resulting in an acceleration of the flow with time. These observations indicate formation of a pair of co-rotating toroidal flow structures inside the spheroidal drop that undergo flow instabilities. As the fluid temperature rises, the amplitude of the secondary flow increases; and beyond a point, the tracers exhibit non-coherent chaotic motion signifying emergence of turbulence inside the drop. Assuming that the observed laminar-turbulent transition is shear-layer type, the internal structure of the toroidal loops is used to develop a semi- empirical correlation for the onset of turbulence. Our calculations indicate that the suggested correlation is in modest agreement with the experimental data, with the transition occurring at a Reynolds number of 600.

Hyers, R. W.; Trapaga, G.; Abedian, B.; Curreri, Peter A. (Technical Monitor)

2002-01-01

3

Laminar-Turbulent Transition in an Electromagnetically-Levitated Droplet  

NASA Technical Reports Server (NTRS)

During experiments on the MSL-1 (First Microgravity Science Laboratory) mission of the Space Shuttle (STS-83 and STS-94, April and July 1997), a droplet of palladium-silicon alloy was electromagnetically levitated for viscosity measurements. For the non-deforming droplet, the resultant MHD flow inside the drop can be inferred from motion of impurity particulates on the surface. In the experiments, subsequent to melting, Joule heating produces a continuous reduction of viscosity of the fluid resulting in an acceleration of the flow with time. These observations indicate formation of a pair of corotating toroidal flow structures inside the spheroidal drop that undergo flow instabilities. As the fluid temperature rises, the amplitude of the secondary flow increases; and beyond a point, the tracers exhibit non-coherent chaotic motion signifying emergence of turbulence inside the drop. Assuming that the observed laminar-turbulent transition is shear-layer type, the internal structure of the toroidal loops is used to develop a semi-empirical correlation for the onset of turbulence. Our calculations indicate that the suggested correlation is in modest agreement with the experimental data, with the transition occurring at a Reynolds number of 600.

Hyers, Robert W.; Curreri, Peter A. (Technical Monitor)

2002-01-01

4

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

5

Natural laminar-turbulent transition delay by dielectric barrier discharge  

NASA Astrophysics Data System (ADS)

The use dielectric barrier discharge for the delay of laminar turbulent transition excited by natural flow disturbances in a quiet wind-tunnel was investigated experimentally. Optimal electrodes location and the operational regime of high-voltage impulse generator provided maximal downstream shift of transition location were found. It was demonstrated that the 10% increase of the laminar part of boundary layer can be obtained using barrier discharge with the cross-flow electrodes. This gives up to 20% friction drag reduction.

Ustinov, Maxim; Kogan, Mikhail; Litvinov, Vladimir; Uspensky, Alexander

2011-12-01

6

Oblique laminar-turbulent interfaces in plane shear flows.  

PubMed

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

Duguet, Yohann; Schlatter, Philipp

2013-01-18

7

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

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

8

Supersonic quiet-tunnel development for laminar-turbulent transition research  

NASA Technical Reports Server (NTRS)

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.

Schneider, Steven P.

1995-01-01

9

Evaluation of laminar-turbulent transition and equilibrium near wall turbulence models  

SciTech Connect

Accurate prediction of laminar-turbulent transition as well as fully turbulent flows is of much practical importance. In this study, both topics are investigated. The e{sup n} method is used to predict transition locations for flows with various angles of attack around on NACA 0012 airfoil. After the transition point the {kappa}-{epsilon} turbulence model is adopted. Computations for flow over a flat plate are done to understand the impact of grid distribution and the wall function treatment on the performance of the {kappa}-{epsilon} turbulence model. In attached and mildly separated flows, satisfactory predictions can be made with the pragmatic e{sup n} transition model and the {kappa}-{epsilon} turbulence model.

He, X.; Senocak, I.; Shyy, W.; Gangadharan, S.N.; Thakur, S.

2000-02-11

10

Transitions and interactions of inviscid/viscous, compressible/incompressible and laminar/turbulent flows  

NASA Astrophysics Data System (ADS)

This paper addresses the flow field-dependent variation (FDV) methods in which complex physical phenomena are taken into account in the final form of partial differential equations to be solved so that finite difference methods (FDM) or finite element methods (FEM) themselves will not dictate the physics, but rather they are no more than simply the options how to discretize between adjacent nodal points or within an element. The variation parameters introduced in the formulation are calculated from the current flow field based on changes of Mach numbers, Reynolds numbers, Peclet numbers and Damkohler numbers between adjacent nodal points, which play many significant roles, such as adjusting the governing equations (hyperbolic, parabolic and/or elliptic), resolving various physical phenomena and controlling the accuracy and stability of the numerical solution. The theory is verified by a number of example problems addressing the physical implications of the variation parameters, which resemble the flow field itself, shock capturing mechanism, transitions and interactions between inviscid/viscous, compressibility/incompressibility and laminar/turbulent flows. Copyright

Chung, T. J.

1999-09-01

11

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

NASA Technical Reports Server (NTRS)

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.

Schneider, Steven P.

1994-01-01

12

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

NASA Astrophysics Data System (ADS)

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 U? 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.

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

2010-09-01

13

Numerical study of laminar-turbulent transition on a plate in a low-speed tunnel with contoured wall  

NASA Astrophysics Data System (ADS)

Laminar-turbulent transition flow phenomena on a flat plate in a low-speed wind tunnel at different Reynolds numbers were studied numerically. The flow calculation is based on an inviscid/boundary layer interaction method with modified Abu-Ghannam/Shaw(AGS) transition criterion. The test section has non-symmetrical contoured walls, and the plate is located biased the bottom side with a height ratio of 26:14. In test case of steady flow, a laminar-turbulent transition takes place and a small separation bubble occurs on the upper side of the plate, when the inlet Reynolds number is as small as 0.631×10-6. The predicted transition location agrees well with that of the test results, but the separation bubble is hardly to see from the calculated velocity profiles though the printed data of velocity in this region do show the negative values. The further numerical predictions with different Reynolds numbers corresponding to the incoming flow velocities show that when the Reynolds number is greater than 1.379×10-6, the separation bubble does not occur, which is coincident with the experimental results. The influence of the side wall geometry on the transition on the plate is also studied.

Feng, Zhenping; Lou, Weiliang; Hourmouziadis, Jean

1999-06-01

14

A theoretical model and experiments on the nonlinear dynamics of parallel plates subjected to laminar/turbulent squeeze-film forces  

NASA Astrophysics Data System (ADS)

Squeeze film dynamical effects are relevant in many industrial contexts, bearings and seals being the most conspicuous applications, but also in other industrial contexts, for instance when dealing with the seismic excitation of spent fuel racks. The significant nonlinearity of the squeeze-film forces which arise prevents the use of linearized flow models, and a fully nonlinear formulation must be used for adequate computational predictions. Because it can easily accommodate both laminar and turbulence flow effects, a simplified bulk-flow model based on gap-averaged Navier-Stokes equations, incorporating all relevant inertial and dissipative terms was previously developed by the authors, assuming a constant skin-friction coefficient. In this paper we develop an improved theoretical formulation, where the dependence of the friction coefficient on the local flow velocity is explicitly accounted for, such that it can be applied to laminar, turbulent and mixed flows. Numerical solutions for both the basic and improved nonlinear one-dimensional time-domain formulations are presented in the paper. Furthermore, we present and discuss the results of an extensive series of experiments performed at CEA/Saclay, which were performed on a test rig consisting on a long gravity-driven instrumented plate of rectangular shape colliding with a planar surface. Theoretical results stemming from both theoretical flow models are confronted with the experimental measurements, in order to assert the strengths and drawbacks of the simpler original model, as well as the improvements brought by the new but more involved flow formulation.

Piteau, Philippe; Antunes, José

2012-08-01

15

Investigation of laminar-turbulent transition in supersonic boundary layers in an axisymmetric aerophysical flight complex and in a model in a wind tunnel in the presence of heat transfer and suction of air  

Microsoft Academic Search

Analysis is made of the problems associated with laminar-turbulent transition in wall boundary layers, as well as of scale\\u000a effects observed in the investigation of laminar-turbulent transition in wind tunnels and laminarization of flow. Flight-performance\\u000a data are given on the Reynolds number and on the gradient criterion of stability at the beginning of transition on the nose\\u000a part of the

A. I. Leontiev; A. M. Pavlyuchenko

2008-01-01

16

The effect of neutrally buoyant finite-size particles on channel flows in the laminar-turbulent transition regime  

NASA Astrophysics Data System (ADS)

The presence of finite-size particles in a channel flow close to the laminar-turbulent transition is simulated with the Force Coupling Method which allows two-way coupling with the flow dynamics. Spherical particles with channel height-to-particle diameter ratio of 16 are initially randomly seeded in a fluctuating flow above the critical Reynolds number corresponding to single phase flow relaminarization. When steady-state is reached, the particle volume fraction is homogeneously distributed in the channel cross-section (? ? 5%) except in the near-wall region where it is larger due to inertia-driven migration. Turbulence statistics (intensity of velocity fluctuations, small-scale vortical structures, wall shear stress) calculated in the fully coupled two-phase flow simulations are compared to single-phase flow data in the transition regime. It is observed that particles increase the transverse r.m.s. flow velocity fluctuations and they break down the flow coherent structures into smaller, more numerous and sustained eddies, preventing the flow to relaminarize at the single-phase critical Reynolds number. When the Reynolds number is further decreased and the suspension flow becomes laminar, the wall friction coefficient recovers the evolution of the laminar single-phase law provided that the suspension viscosity is used in the Reynolds number definition. The residual velocity fluctuations in the suspension correspond to a regime of particulate shear-induced agitation.

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

2013-12-01

17

Numerical study of laminar-turbulent transition in particle-laden channel flow  

NASA Astrophysics Data System (ADS)

We present direct numerical simulations of subcritical transition to turbulence in a particle-laden channel flow, with particles assumed rigid, spherical, and heavier than the fluid. The equations describing the fluid flow are solved with an Eulerian mesh, whereas those describing the particle dynamics are solved by Lagrangian tracking. Two-way coupling between fluid and particles is modeled with Stokes drag. The numerical code is first validated against previous results from linear stability: the nonmodal growth of streamwise vortices resulting in streamwise streaks is still the most efficient mechanism for linear disturbance amplification at subcritical conditions as for the case of a single phase fluid. To analyze the full nonlinear transition, we examine two scenarios well studied in the literature: (1) transition initiated by streamwise independent counter-rotating streamwise vortices and one three-dimensional mode and (2) oblique transition, initiated by the nonlinear interaction of two symmetric oblique waves. The threshold energy for transition is computed, and it is demonstrated that for both scenarios the transition may be facilitated by the presence of particles at low number density. This is due to the fact that particles may introduce in the system detrimental disturbances of length scales not initially present. At higher concentrations, conversely, we note an increase of the disturbance energy needed for transition. The threshold energy for the oblique scenario shows a more significant increase in the presence of particles, by a factor about four. Interestingly, for the streamwise-vortex scenario the time at which transition occurs increases with the particle volume fraction when considering disturbances of equal initial energy. These results are explained by considering the reduced amplification of oblique modes in the two-phase flow. The results from these two classical scenarios indicate that, although linear stability analysis shows hardly any effect on optimal growth, particles do influence secondary instabilities and streak breakdown. These effects can be responsible of the reduced drag observed in turbulent channel flow laden with heavy particles.

Klinkenberg, Joy; Sardina, Gaetano; de Lange, H. C.; Brandt, Luca

2013-04-01

18

Numerical study of laminar-turbulent transition in particle-laden channel flow.  

PubMed

We present direct numerical simulations of subcritical transition to turbulence in a particle-laden channel flow, with particles assumed rigid, spherical, and heavier than the fluid. The equations describing the fluid flow are solved with an Eulerian mesh, whereas those describing the particle dynamics are solved by Lagrangian tracking. Two-way coupling between fluid and particles is modeled with Stokes drag. The numerical code is first validated against previous results from linear stability: the nonmodal growth of streamwise vortices resulting in streamwise streaks is still the most efficient mechanism for linear disturbance amplification at subcritical conditions as for the case of a single phase fluid. To analyze the full nonlinear transition, we examine two scenarios well studied in the literature: (1) transition initiated by streamwise independent counter-rotating streamwise vortices and one three-dimensional mode and (2) oblique transition, initiated by the nonlinear interaction of two symmetric oblique waves. The threshold energy for transition is computed, and it is demonstrated that for both scenarios the transition may be facilitated by the presence of particles at low number density. This is due to the fact that particles may introduce in the system detrimental disturbances of length scales not initially present. At higher concentrations, conversely, we note an increase of the disturbance energy needed for transition. The threshold energy for the oblique scenario shows a more significant increase in the presence of particles, by a factor about four. Interestingly, for the streamwise-vortex scenario the time at which transition occurs increases with the particle volume fraction when considering disturbances of equal initial energy. These results are explained by considering the reduced amplification of oblique modes in the two-phase flow. The results from these two classical scenarios indicate that, although linear stability analysis shows hardly any effect on optimal growth, particles do influence secondary instabilities and streak breakdown. These effects can be responsible of the reduced drag observed in turbulent channel flow laden with heavy particles. PMID:23679517

Klinkenberg, Joy; Sardina, Gaetano; de Lange, H C; Brandt, Luca

2013-04-01

19

A continuous time random walk model with multiple characteristic times  

Microsoft Academic Search

In this paper we consider a continuous time random walk (CTRW) model with a decoupled jump pdf. Further, we consider an approximate jump length pdf; for the waiting time pdf we do not use any approximation and we employ a function which depends on multiple characteristic times given by a sum of exponential functions. This waiting time pdf can reproduce

Kwok Sau Fa; R S Mendes

2010-01-01

20

Representation of Time Dependent Characteristics of Metals.  

National Technical Information Service (NTIS)

A new approach to the representation of time dependent inelastic material behavior is described. Realistic properties such as strain hardening, strain rate effects, and anelasticity can be incorporated in this description which is particularly well suited...

S. R. Bodner Y. Partom

1972-01-01

21

Proton Event Time Characteristics and Radio Burst Data.  

National Technical Information Service (NTIS)

Various studies undertaken for relating the proton event time characteristics to radio burst data are described. Eastern hemispheric events generally have a much larger onset time compared to the Western events. For western hemispheric events, the rise ti...

P. Bakshi T. Nguyen

1981-01-01

22

[Study of time characteristics in spectrometer dynamic sampling].  

PubMed

The present paper uses the relationship between sawtooth wave's amplitude and time's linear code to test and analyze a spectrometer. The result shows that the sampling time is associated with the integration time and the sampling interval closely relates with integral time, and the fluctuation range of sampling interval was further explored. This paper provides the reference of the integral time for the analysis focused on spectrum time characteristic, proposes a method to evaluate the dynamic time properties, and contributes to the assessment and application of the dynamic characteristics of the spectrum. PMID:25007643

Xiong, Hui; Yang, Xue; Zhou, Mei; Li, Gang; Lin, Ling

2014-04-01

23

Predicting proton event time characteristics from radio burst data  

SciTech Connect

For events originating on the Western hemisphere, the delay before onset of the solar flare protons is shown to be well correlated (r about 0.80) with the rise time of the associated radio-burst at 2-3 GHz or the rise time of the H sub alpha flare. The peak flux time of the protons is shown to be very well correlated (r about 0.90) with the delay before onset, and fairly well correlated (r about 0.70) with the flare or radio rise time. These results allow a prediction of the proton event time characteristics from real time radio burst data.

Bakshi, P.; Nguyen, T.

1981-06-01

24

Characteristic times of biased random walks on complex networks  

NASA Astrophysics Data System (ADS)

We consider degree-biased random walkers whose probability to move from a node to one of its neighbors of degree k is proportional to k?, where ? 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 ? which minimizes the three characteristic times differs from the value ?min=-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 ?min in the range [-1,-0.5], while disassortative networks have ?min in the range [-0.5,0]. We derive an analytical relation between the degree correlation exponent ? and the optimal bias value ?min, 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.

Bonaventura, Moreno; Nicosia, Vincenzo; Latora, Vito

2014-01-01

25

Characteristic times of biased random walks on complex networks.  

PubMed

We consider degree-biased random walkers whose probability to move from a node to one of its neighbors of degree k is proportional to k(?), where ? 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 ? which minimizes the three characteristic times differs from the value ?(min)=-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 ?(min) in the range [-1,-0.5], while disassortative networks have ?(min) in the range [-0.5,0]. We derive an analytical relation between the degree correlation exponent ? and the optimal bias value ?(min), 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. PMID:24580277

Bonaventura, Moreno; Nicosia, Vincenzo; Latora, Vito

2014-01-01

26

Time-Invariant Characteristics of Naval Power-Line Channels  

Microsoft Academic Search

In this paper, time-invariant characteristics of power-line communications (PLC) channels in ships are evidenced. A multiport channel model derived from transmission-line theory is used to investigate the frequency response under various loading conditions. The time-invariant power-line channel in ships is mainly due to the low impedance of parallel cables attached to the switchboard acting as an electrical node. Based on

Tao Zheng; Marco Raugi; Mauro Tucci

2012-01-01

27

Tailoring explicit time-marching schemes to improve convergence characteristics  

NASA Technical Reports Server (NTRS)

Multi-stage time-stepping schemes, tailored to chosen spatial-differencing operators, are derived and tested. The schemes are constructed to give optimal damping of the high-frequency waves. They are ideal for use with multi-grid acceleration. The concept of characteristic time-stepping, necessary for the extension of the scalar analysis to systems of equations, is presented. The schemes show a marked improvement over Runge-Kutta schemes.

Powell, Kenneth G.; Vanleer, Bram

1990-01-01

28

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

NASA Astrophysics Data System (ADS)

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.

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

2006-06-01

29

Effects of Accuracy Feedback on Fractal Characteristics of Time Estimation  

PubMed Central

The current experiment investigated the effect of visual accuracy feedback on the structure of variability of time interval estimates in the continuation tapping paradigm. Participants were asked to repeatedly estimate a 1-s interval for a prolonged period of time by tapping their index finger. In some conditions, participants received accuracy feedback after every estimate, whereas in other conditions, no feedback was given. Also, the likelihood of receiving visual feedback was manipulated by adjusting the tolerance band around the 1-s target interval so that feedback was displayed only if the temporal estimate deviated from the target interval by more than 50, 100, or 200?ms respectively. We analyzed the structure of variability of the inter-tap intervals with fractal and multifractal methods that allow for a quantification of complex long-range correlation patterns in the timing performance. Our results indicate that feedback changes the long-range correlation structure of time estimates: Increased amounts of feedback lead to a decrease in fractal long-range correlations, as well to a decrease in the magnitude of local fluctuations in the performance. The multifractal characteristics of the time estimates were not impacted by the presence of accuracy feedback. Nevertheless, most of the data sets show significant multifractal signatures. We interpret these findings as showing that feedback acts to constrain and possibly reorganize timing performance. Implications for mechanistic and complex systems-based theories of timing behavior are discussed.

Kuznetsov, Nikita A.; Wallot, Sebastian

2011-01-01

30

Potentially hazardous comet warning times, characteristics, trends and countermeasures  

NASA Astrophysics Data System (ADS)

This research seeks to determine orbital trends and characteristics of comets discovered over recorded history; specifically "warning times" associated with comets that come within 1.3 astronomical unit (AU) of the Earth, called Near-Earth Objects (NEOs), and Potentially Hazardous Objects (PHOs) which come within 0.05 AU of Earth's Minimum Orbit Intersection Distance (MOID) . In this work, "warning time" means the time from discovery to perigee/closest approach to Earth, including negative warning times when the comet is discovered after close approach. This study proposes that warning times for comets approaching Earth should be increasing with increased telescope technology and an increased number of surveys focused on NEOs in the past decades. Quantification occurs by investigating all known comets through recorded history, restricting this group to relevant Near-Earth Comets (NECs), and predicting appearance and warning times of future comets using discovered trends. Data for this study was obtained from the Jet Propulsion Laboratory's (JPL) online HORIZONS system. The system has highly accurate ephemerides for asteroids and comets (612829 and 3,196 respectively on April 12, 2013) as well as other Solar System objects as well as orbital parameters and visualization tool for those objects. HORIZONS was used to build a database of all discovered comets up until February 8, 2013. The database includes: date discovered, date and close approach distance, inclination, eccentricity, total and nuclear magnitude, and several other observations used in the orbital fit. The data was then analyzed for characteristics using both MATLAB and Excel for analysis and numerical computations.

Phelps, Lyrica L.

31

Full-Time and Part-Time Subgroup Differences in Job Attitudes and Demographic Characteristics  

Microsoft Academic Search

This study examined the hypothesis that subgroups of part-timers differ from each other and from full-timers in their demographic characteristics, organizational commitment, and other job-related perceptions. Frame of reference differences and differing patterns of relationship investments are thought to account for these differences. We examined these group differences using samples of 850 full-time and 1490 part-time unionized employees. The part-time

Robert R. Sinclair; James E. Martin; Robert P. Michel

1999-01-01

32

Continuous-Time Finance and the Waiting Time Distribution: Multiple Characteristic Times  

NASA Astrophysics Data System (ADS)

In this paper, we model the tick-by-tick dynamics of markets by using the continuous-time random walk (CTRW) model. We employ a sum of products of power law and stretched exponential functions for the waiting time probability distribution function; this function can fit well the waiting time distribution for BUND futures traded at LIFFE in 1997.

Fa, Kwok Sau

2012-09-01

33

Magnetopause characteristics at 0840-1040 hours local time  

NASA Technical Reports Server (NTRS)

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.

Williams, D. J.

1980-01-01

34

Picosecond time response characteristics of microchannel plate PMT detectors  

NASA Astrophysics Data System (ADS)

The output pulse width in the time response of photo-multiplier tubes (PMT) is much faster in micro-channel plate (MCP) models compared to more standard dynode chain PMTs due to a vastly reduced variation in the path length of the electrons through the amplifying system. Typically the pulse widths can be in the region of 200ps compared to the nanosecond domain occupied by the best conventional PMTs. Photek manufacture PMTs with one, two or three MCPs depending on the gain required, and also use the same structure without any MCPs to work as simple photodiodes. We demonstrate the variation of output pulse characteristics due to the number and design of MCPs in a range of PMT models and illustrate the importance of having a properly designed 50ohm transmission line to deliver the pulse from the detector.

Milnes, James S.; Howorth, J.

2005-03-01

35

Space-Time Characteristics of Rainfall Diurnal Variations  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

36

Measurements of pilot time delay as influenced by controller characteristics and vehicles time delays  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

37

Student Part-Time Employment: Characteristics and Consequences  

ERIC Educational Resources Information Center

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…

Robotham, David

2012-01-01

38

Laminar-turbulent transition in an electromagnetically levitated droplet  

Microsoft Academic Search

During experiments on the MSL-1 (first microgravity science laboratory) mission of the space shuttle (STS-83 and STS-94, April\\u000a and July 1997), a droplet of palladium-silicon alloy was electromagnetically levitated for viscosity measurements. For the\\u000a nondeforming droplet, the resultant magnetohydrodynamic (MHD) flow inside the drop can be inferred from motion of impurity\\u000a particulates on the surface. In the experiments, subsequent to

R. W. Hyers; G. Trapaga; B. Abedian

2003-01-01

39

Laminar/turbulent oscillating flow in circular pipes  

NASA Technical Reports Server (NTRS)

A two-dimensional oscillating flow analysis was conducted simulating the gas flow inside Stirling engine heat exchangers. Both laminar and turbulent oscillating pipe flow were investigated numerically for Re(max) = 1920 (Va = 80), 10,800 (Va = 272), 19,300 (Va = 272), and 60,800 (Va = 126). The results are compared with experimental results of previous investigators. Predictions of the flow regime are also checked by comparing velocity amplitudes and phase difference with those from laminar theory and quasi-steady profile. A high Reynolds number k-epsilon turbulence model was used for turbulent oscillating pipe flow. Finally, the performance of the k-epsilon model was evaluated to explore the applicability of quasi-steady turbulent models to unsteady oscillating flow analysis.

Ahn, Kyung H.; Ibrahim, Mounir B.

1992-01-01

40

Laminar/turbulent oscillating flow in circular pipes  

NASA Astrophysics Data System (ADS)

A two-dimensional oscillating flow analysis was conducted simulating the gas flow inside Stirling engine heat exchangers. Both laminar and turbulent oscillating pipe flow were investigated numerically for Re(max) = 1920 (Va = 80), 10,800 (Va = 272), 19,300 (Va = 272), and 60,800 (Va = 126). The results are compared with experimental results of previous investigators. Predictions of the flow regime are also checked by comparing velocity amplitudes and phase difference with those from laminar theory and quasi-steady profile. A high Reynolds number k-epsilon turbulence model was used for turbulent oscillating pipe flow. Finally, the performance of the k-epsilon model was evaluated to explore the applicability of quasi-steady turbulent models to unsteady oscillating flow analysis.

Ahn, Kyung H.; Ibrahim, Mounir B.

1992-12-01

41

Characteristic-Based Clustering for Time Series Data  

Microsoft Academic Search

With the growing importance of time series clustering research, particularly for similarity searches amongst long time series such as those arising in medicine or finance, it is critical for us to find a way to resolve the outstanding problems that make most clustering methods impractical under certain circumstances. When the time series is very long, some clustering algorithms may fail

Xiaozhe Wang; Kate A. Smith; Rob J. Hyndman

2006-01-01

42

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

ERIC Educational Resources Information Center

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'…

Frech, Adrianne; Kimbro, Rachel Tolbert

2011-01-01

43

Characteristics of Sheath and Presheath Recovery during Pulse Fall Time  

NASA Astrophysics Data System (ADS)

Recovery motion of sheath and presheath is investigated with various fall times of negative bias on the target. Experimental observation was carried out with the collisionless argon plasma and the various pulses with fast and slow fall times which are shorter and longer than the ion transition time scaled of 3/?pi(?pi=ion plasma frequency), respectively. Electrical probe was employed to measure the density distribution. Ion distribution and speed near the target are important factors in determining the position of sheath . For the slow fall time, sheath and presheath boundaries recover with the same speed. Child-Langmuir sheath continuously persists due to enough time to rearrange ions and electrons. For the fast fall time, ion matrix sheath, which is immediately responding to the target voltage, leads the recovery of sheath with supersonic speed. Presheath follows ion inertia that was formed at the plateau time and its speed does not follow the speed of the sheath. Voltage-responding electrons enhance the ion diffusion from the bulk plasma, resulting in the plasma filling in the depletion region. For the intermediate fall time (3/?pi), the transformation from ion matrix to Child-Langmuir sheath occurs after ion responds. Detailed results will be presented.

Choe, Jae-Myung; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, Gon-Ho

2012-10-01

44

Predicting Proton Event Time Characteristics from Radio Burst Data.  

National Technical Information Service (NTIS)

For events originating on the Western hemisphere, the delay before onset of the solar flare protons is shown to be well correlated (r about 0.80) with the rise time of the associated radio-burst at 2-3 GHz or the rise time of the h sub alpha flare. The pe...

P. Bakshi T. Nguyen

1981-01-01

45

Statistical Characteristics of Irreversible Predictability Time in Regional Ocean Models.  

National Technical Information Service (NTIS)

Probabilistic aspects of regional ocean model predictability is analyzed using the probability density function (PDF) of the irreversible predictability time (IPT) (called tau-PDF) computed from an unconstrained ensemble of stochastic perturbations in ini...

L. M. Ivanov P. C. Chu

2005-01-01

46

Picosecond time response characteristics of microchannel plate PMT detectors  

Microsoft Academic Search

The output pulse width in the time response of photo-multiplier tubes (PMT) is much faster in micro-channel plate (MCP) models compared to more standard dynode chain PMTs due to a vastly reduced variation in the path length of the electrons through the amplifying system. Typically the pulse widths can be in the region of 200ps compared to the nanosecond domain

James S. Milnes; J. Howorth

2005-01-01

47

Timing characteristic of large cylindrical NE213 counters  

Microsoft Academic Search

The fast neutron time-of-flight resolution of cylindrical NE213 scintillation counters for an energy range 3-21 MeV is measured and compared. Detector dimensions vary from 10.0 cm diameter by 2.5 cm thick to 38 cm diameter by 10 cm thick. Discrete energy neutron groups are produced using the natB(d,n) reaction, Ed = 6.7 MeV, 7.5 MeV. Present address: Booz-Allen and Hamilton

J. R. M. Annand; R. W. Finlay; M. A. Polster

1985-01-01

48

Inverting Source Time Functions to determine the fault kinematic characteristics  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

49

Capacitance-voltage characteristics of a 4,4'-bis[(N-carbazole)styryl]biphenyl based organic light-emitting diode: Implications for characteristic times and their distribution  

NASA Astrophysics Data System (ADS)

The characteristic times and their distributions of a fluorescent 4,4'-bis[(N-carbazole)styryl]biphenyl-based organic light-emitting diode (OLED) were studied using impedance spectroscopy. The four defined characteristic times (transit time, recombination time, trapping time, and ac characteristic time) and their dc bias dependences were obtained from the frequency dependence of capacitance. The trapped carrier density distribution in the time domain was revealed from the voltage dependence of the OLED. The relative value of each characteristic time is suggested to play an important role in determining the profile of the frequency- and voltage-dependent capacitance of OLEDs.

Zhang, Le; Nakanotani, Hajime; Adachi, Chihaya

2013-08-01

50

The relationship among college science student achievement, engaged time, and personal characteristics  

Microsoft Academic Search

The relationships among college student science achievement, engaged time (observed and perceived), and personal characteristics of academic aptitude, reasoning ability, attitude toward science, and locus of control were investigated. Measures of personal characteristics were obtained from the subjects (N= 76) of a private, liberal arts junior college before observations began in the lecture classes for the quarter. Instruments used to

T. Franklin Johnson; David P. Butts

1983-01-01

51

The Impact of Item Format and Examinee Characteristics on Response Times  

ERIC Educational Resources Information Center

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

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

2013-01-01

52

Characteristics of Time-Series Data Collected through Curriculum-Based Reading Measurement.  

ERIC Educational Resources Information Center

The statistical properties of curriculum-based time-series data were investigated for 67 learning disabled students (grades 1-7). Results suggest that reading growth over time may be described by a negatively accelerated curve and that the statistical characteristics of time-series data are not necessarily independent in naturally occurring data.…

Skiba, Russell J.; And Others

1986-01-01

53

Examining Information Needs for Efficient Motor Carrier Transportation by Investigating Travel Time Characteristics and Logistics.  

National Technical Information Service (NTIS)

This report presents both survey results and field data analysis investigating information needs for motor carrier logistics. Relevant research in the area of estimating travel time characteristics is presented. Survey results of trucking companies and tr...

L. R. Rilett W. L. Eisele

2002-01-01

54

Full-Time and Part-Time Subgroup Differences in Job Attitudes and Demographic Characteristics.  

ERIC Educational Resources Information Center

Comparison of part-time employees (142 moonlighters, 365 students, 661 earning supplemental income, 556 primary breadwinners) and 850 full-time workers showed that part timers were more likely to be female, under 30, and earn over 50% of family income. Moonlighters' commitment was influenced by different variables than that of other part-timers.…

Sinclair, Robert R.; Martin, James E.; Michel, Robert P.

1999-01-01

55

[Study on time-resolved spectra shape of aluminum plasma's characteristic radiation].  

PubMed

Aluminum plasma was obtained with a Nd:YAG pulsed laser beam ablating target aluminum. The radiation information of the plasma was recorded on a time and space resolution basis. So the time-resolved spectra of Al plasma were obtained with a time delay of 10 to 10,000 ns. From those spectra, we acquired the time-resolved spectra of Al I 396.15 and Al I 394.40 nm, the characteristic lines of Al plasma radiation. The shape of the two characteristic lines was studied from 800 to 10,000 ns delay. Further more, the two characteristic lines were respectively fitted in Lorentz profile and Gauss profile with Lorentz and Gauss function. As a result, all the characteristic lines after 1000 ns delay well fitted Lorentz profile, and before that time, they also fitted each other, but slightly. In the whole range of time delay, the experimental lines departed by far from the fitted Gauss profile. So we could conclude that the shape of Al I 396.15 and that of Al I 394.40 nm were all Lorentz lines, not Gauss ones. The half-high-full widths of the two characteristic lines were determined, aided with the Lorentz lines fitting. Compared with the natural widths of the two lines, the experimental results were much wider than the theoretical values. PMID:15768969

Song, Yi-zhong; He, An-zhi

2004-01-01

56

Characteristic Variations of Sea Surface Temperature with Multiple Time Scales in the North Pacific  

Microsoft Academic Search

Temporal evolution and spectral structure of sea surface temperature (SST) anomalies in the North Pacific over the last 37 years are investigated on the three characteristic time scales: shorter than 24 months (HF), 24-60 months (ES), and longer than 60 months (DC). The leading empirical-orthogonal function (EOF) for the DC time scale is characterized by a zonally elongated monopole centered

Youichi Tanimoto; Kimio Hanawa; Yoshiaki Toba; Naoto Iwasaka

1993-01-01

57

Waveform relaxation synthesis of time-domain characteristic model of loaded microstrip from FDTD simulation  

Microsoft Academic Search

From the finite-difference time-domain (FDTD) simulation of response voltages and currents of a microstrip terminated by a step-pulse excitation voltage source and a resistor load, the time-domain characteristic model (TDCM) of the microstrip is synthesized by use of the waveform relaxation method, which is based on the iteration and deconvolution techniques. As an example, the extracted model is applied to

Qing-Xin Chu; Fung-Yuel Chang

1997-01-01

58

Membrane bioreactor operation at short solids retention times: performance and biomass characteristics  

Microsoft Academic Search

This study investigated the performance and biomass characteristics of a membrane bioreactor (MBR) and a completely mixed activated sludge (CMAS) system operated at short solids retention times (SRT) ranging from 0.25 to 5d and hydraulic retention times of 3 and 6h. The lab-scale reactors were fed with synthetic wastewater to ensure consistency in feed composition. Results show the MBR was

How Y. Ng; Slawomir W. Hermanowicz

2005-01-01

59

Efficient computation for dynamic responses of systems with time-varying characteristics  

Microsoft Academic Search

Based on Neumman series and epsilon-algorithm, an efficient computation for dynamic responses of systems with arbitrary time-varying\\u000a characteristics is investigated. Avoiding the calculation for the inverses of the equivalent stiffness matrices in each time\\u000a step, the computation effort of the proposed method is reduced compared with the full analysis of Newmark method. The validity\\u000a and applications of the proposed method

Liang Ma; Yudong Chen; Suhuan Chen; Guangwei Meng

2009-01-01

60

Evaluations of Trial Competency and Mental State at Time of Offense: Report Characteristics  

Microsoft Academic Search

Despite the dramatic increase in conceptual and empirical attention to forensic mental health assessment that has occurred within the last 10 years, there is little published research on the normative characteristics of such evaluations. In the present study, a total of 277 reports describing evaluations of competency to stand trial and\\/or mental state at the time of the offense, based

Kirk Heilbrun; Steven Collins

1995-01-01

61

Chaotic Characteristic of Time Series of Partial Discharge in Oil-Paper Insulation  

NASA Astrophysics Data System (ADS)

The chaotic characteristics of time series of five partial discharge (PD) patterns in oil-paper insulation are studied. The results verify obvious chaotic characteristic of the time series of discharge signals and the fact that PD is a chaotic process. These time series have distinctive features, and the chaotic attractors obtained from time series differed greatly from each other by shapes in the phase space, so they could be used to qualitatively identify the PD patterns. The phase space parameters are selected, then the chaotic characteristic quantities can be extracted. These quantities could quantificationally characterize the PD patterns. The effects on pattern recognition of PRPD and CAPD are compared by using the neural network of radial basis function. The results show that both of the two recognition methods work well and have their respective advantages. Then, both the statistical operators under PRPD mode and the chaotic characteristic quantities under CAPD mode are selected comprehensively as the input vectors of neural network, and the PD pattern recognition accuracy is thereby greatly improved.

Luo, Yongfen; Ji, Haiying; Huang, Ping; Li, Yanming

2011-12-01

62

Influence of harvest time on fuel characteristics of five potential energy crops in northern China  

Microsoft Academic Search

Five potential energy crops in northern China were examined for fuel characteristics over different harvest times to test whether or not a delayed harvest improves fuel quality in a semiarid area in China as is the case in northern Europe and North America. The five crops include indigo bush (Amorpha fruticosa), sand willow (Salix cheilophila), switch grass (Panicum virgatum), reed

Shaojun Xiong; Quan-Guo Zhang; Da-Yong Zhang; Rolf Olsson

2008-01-01

63

Estimation of characteristic damage time of food materials in pulsed-electric fields  

Microsoft Academic Search

A method based on the electrical conductivity measurements is proposed to estimate the characteristic damage time (?) of a food material in pulsed-electric fields (PEF). Empirical dependencies of ? versus electric field intensity E are obtained for apple, carrot and potato tissues. The generalized electroporation theory accounting for the sphericity of biological cells and distribution of their geometric sizes gives

N. I Lebovka; M. I Bazhal; E Vorobiev

2002-01-01

64

Force-Time Characteristics and Running Velocity of Male Sprinters During the Acceleration Phase of Sprinting.  

ERIC Educational Resources Information Center

Investigation of the force-time characteristics of eight male sprinters during the acceleration phase of the sprint start suggested that the braking and propulsion phases occur immediately after the block phase and that muscle strength strongly affects running velocity in the sprint start. (Author/CB)

Mero, Antti

1988-01-01

65

Inhibition of Dopamine Release Via Presynaptic D2 Receptors: Time Course and Functional Characteristics In Vivo  

Microsoft Academic Search

Most neurotransmitters inhibit their own release through auto- receptors. However, the physiological functions of these pre- synaptic inhibitions are still poorly understood, in part because their time course and functional characteristics have not been described in vivo. Dopamine inhibits its own release through D2 autoreceptors. Here, the part played by autoinhibition in the relationship between impulse flow and dopamine release

Marianne Benoit-Marand; Emiliana Borrelli; Francois Gonon

2001-01-01

66

Influence of time characteristics of beam extraction on coherent Bremsstrahlung spectra  

SciTech Connect

This paper describes a new method of increasing the degree of polarization chromaticity of the coherent Bremsstrahlung spectra. The authors consider the time characteristics of electron-beam extraction from the Erevan synchrotron. By adjusting the extraction regime, the Bresstrahlung beam parameters can be controlled. Practical applications of the new method are discussed.

Avakyan, R.O.; Avetisyan, A.E.; Sarkisyan, R.T.; Simonyan, K.A.; Taroyan, S.P.; Zapol'skii, N.A.

1985-09-01

67

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

ERIC Educational Resources Information Center

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…

Hyun, Eunsook; Kretovics, Mark; Crowe, Alicia

2006-01-01

68

The relationship among college science student achievement, engaged time, and personal characteristics  

NASA Astrophysics Data System (ADS)

The relationships among college student science achievement, engaged time (observed and perceived), and personal characteristics of academic aptitude, reasoning ability, attitude toward science, and locus of control were investigated. Measures of personal characteristics were obtained from the subjects (N= 76) of a private, liberal arts junior college before observations began in the lecture classes for the quarter. Instruments used to measure personal characteristics were Scholastic Aptitude Test, Test of Logical Thinking, Test of Scientific Attitude, and Leven-son's Multidimensional View of Locus of Control. Based on a random selection procedure, student engaged time was observed at least ten times for 11 lectures. Achievement tests were constructed and validated for the biology classes. Data were analyzed by multiple regression procedures. The average achievement scores were positively related to academic aptitude and reasoning ability. Positive relationships were found between observed engaged time and academic aptitude and a negative relationship was found between observed engaged time and reasoning ability. Also a positive relationship was found between perceived engaged time and achievement. Pearson product-moment correlations between achievement and observed engaged time were significant as were the correlations between perceived engaged time and achievement. Measure of engaged time (observed and perceived) were also related to each other. The study's data indicate that students who were observed to be engaged were low in reasoning ability or high in academic aptitude. Those who perceived themselves as being engaged achieved more. College instructors who have knowledge of student academic aptitude and reasoning ability may use this knowledge to improve achievement.Engaged time measures were significantly related to achievement, which indicates an instructor should endeavor to keep the students as engaged as possible to enhance achievement. Students who are engaged or pay attention or perceived they are engaged or paying attention during lecture classes achieve more than students who are observed as nonengaged or perceive themselves as nonengaged.

Johnson, T. Franklin; Butts, David P.

69

Chemical modification of proroot mta to improve handling characteristics and decrease setting time.  

PubMed

Mineral trioxide aggregate (MTA) fulfills many of the ideal properties of a root-end filling material. However, the composition of this material often makes MTA difficult to use, a direct result of its granular consistency, slow setting time, and initial looseness. Additives used by the Portland cement (PC) industry to increase PC's plasticity and decrease its setting time were added first to PC and then to gray MTA in an attempt to improve MTA's handling characteristics, with the combination providing the best handling characteristics tested for its effect on compressive strength (for changes in the original material's properties) and decrease in setting time. An admix of 1% methylcellulose and 2% calcium chloride resulted in a mix of chemically modified MTA that, when compared with unmodified MTA, (1) handled similarly to a reinforced zinc oxide-eugenol cement, (2) gave an approximately equal compressive strength, and (3) set one third faster (57 +/- 3 minutes). PMID:17889696

Ber, Benjamin S; Hatton, John F; Stewart, Gregory P

2007-10-01

70

Current limiting level-time characteristic of a superconducting fault current limiter  

NASA Astrophysics Data System (ADS)

A model superconducting fault current limiter (SE-FCL) has been developed. The adopted superconducting cable is composed of six strands insulated from each other. The current limiting level of the SC-FCL is measured under two types of overcurrent, a sinusoidal and an inrush current. The results show that the current limiting level of the SC-FCL Iq increases with an increase in the rate of rise of the overcurrent. By introducing a new parameter of time-to-quench tf, it is found that Iq increases with decreasing tf. This feature is taken as a current limiting level-time characteristic i.e. the Iq- tf characteristic. The existence of the Iq- tf characteristic found in the SC-FCL is qualitatively explained by measuring current distribution among the six strands. The superconducting cable is driven to the normal state strand by strand. Some delay in time is found from the quench of the first strand to that of the last and this is recognized as an Iq- tf characteristic in its current limiting performance.

Tang, Y. J.; Yokomizu, Y.; Hayakawa, N.; Matsumura, T.; Okubo, H.; Kito, Y.

71

Analysis of the kinetics of lipid peroxidation in terms of characteristic time-points.  

PubMed

Measuring peroxidation of aggregated lipids in model systems (liposomes, micelles, emulsions or microemulsions) as well as in samples of biological origin ex vivo (isolated lipoproteins, blood sera or plasma) is widely used in medical and biological investigations, to evaluate the oxidative stress, antioxidants' efficiency and lipid oxidizability in different pathophysiological states. To avoid possible artifacts, such investigations must be based on the time course of peroxidation (i.e. on kinetic studies). To be able to compare complex kinetic profiles, it is important to characterize them in terms of mechanistically meaningful and experimentally unequivocal parameters. In this review, we characterize the typically observed continuous kinetic profiles in terms of a limited number of characteristic time-points (both commonly used and additional time-points and their combinations) that can be derived from experimental time-dependencies. The meaning of each of the experimentally observed characteristic parameters is presented in terms of rate constants and concentrations, derived on the basis of mechanistic considerations. Theoretical expressions for these characteristic parameters are based on a model that includes both the inhibited peroxidation and the uninhibited peroxidation occurring after consumption of the antioxidant(s). Comparison between theoretically predicted dependencies and experimental data support our treatment considered with special emphasis on transition metals-induced peroxidation of lipoproteins. PMID:24333462

Pinchuk, Ilya; Lichtenberg, Dov

2014-02-01

72

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

NASA Astrophysics Data System (ADS)

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.

Jung, Jae Hee; Lee, Jung Eun

2013-12-01

73

Time-domain leaky modes on layered media - Dispersion characteristics and synthesis of pulsed radiation  

NASA Astrophysics Data System (ADS)

In a recent comprehensive study of short-pulse radiation from current elements in the presence of plane layered dielectric media, various alternatives have been explored for constructing the transient field in terms of spectral-domain wave functions. Two distinctive synthesis options have been structured around conventional time-harmonic and nonconventional time-dependent basis wave functions, respectively. To understand the characteristic properties of each, it is necessary to explore in detail the frequency-wavenumber dispersion relation for the layered environment. Especially interesting is the behavior of the nonconventional time-domain leaky modes which exhibit anomalies not encountered in their conventional time-harmonic counterparts. An example is given of how these time-domain modal basis fields synthesize highly resolved short-pulse radiation from a source in a dielectric layer.

Niu, Feng; Felsen, Leopold B.

1993-06-01

74

Evaluation of Night-Time Pain Characteristics and Quality of Sleep in Postoperative Turkish Orthopedic Patients  

Microsoft Academic Search

This descriptive, correlational study was conducted to determine orthopedic patients’ night-time pain characteristics, their quality of sleep and the contributing factors to poor sleep experiences, and the relationship between pain and sleep. Data were collected by using the McGill Pain Questionnaire-SF (MPQ-SF) and Pittsburgh Sleep Quality Index (PSQI) on the second postoperative day. Data were analyzed using the SPSS version

Funda Esen Büyüky?lmaz; Merdiye ?endir; Rengin Acaro?lu

2011-01-01

75

Characteristics of a 1200 V PT IGBT with trench gate and local life time control  

Microsoft Academic Search

A new 1200 V IGBT with a VCE(sat) of 1.9 V at 125°C and 140 A\\/cm2 has been developed using a trench gate PT (punch-through) structure and local life time control. Compared to state-of-the-art third generation planar devices, this device represents a 30% improvement of on-state losses at almost twice the current density. This paper describes the structure and characteristics

Eric R. Motto; John F. Donlon; H. Takahashi; M. Tabata; H. Iwamoto

1998-01-01

76

Influence of solid retention time on sludge characteristics and effluent quality in immersed membrane bioreactor  

Microsoft Academic Search

Here the effect of solid retention time (SRT) on the concentration of the mixed liquor suspend solid (MLSS), the sludge characteristics,\\u000a the content of extra-cellular polymeric substances (EPS), the viscosity of mixed liquor and effluent quality in the immersed\\u000a membrane bioreactor (IMBR) was investigated. The results indicate that the increase of the EPS content is the main reason\\u000a for the

ZhanPing Cao; JingLi Zhang; HongWei Zhang

2008-01-01

77

Incubation time, functional litter diversity, and habitat characteristics predict litter-mixing effects on decomposition.  

PubMed

Plant diversity influences many fundamental ecosystem functions, including carbon and nutrient dynamics, during litter breakdown. Mixing different litter species causes litter mixtures to lose mass at different rates than expected from component species incubated in isolation. Such nonadditive litter-mixing effects on breakdown processes often occur idiosyncratically because their direction and magnitude change with incubation time, litter species composition, and ecosystem characteristics. Taking advantage of results from 18 litter mixture experiments in streams, we examined whether the direction and magnitude of nonadditive mixing effects are randomly determined. Across 171 tested litter mixtures and 510 incubation time-by-mixture combinations, nonadditive effects on breakdown were common and on average resulted in slightly faster decomposition than expected. In addition, we found that the magnitude of nonadditive effects and the relative balance of positive and negative responses in mixtures change predictably over time, and both were related to an index of functional litter diversity and selected environmental characteristics. Based on these, it should be expected that nonadditive effects are stronger for litter mixtures made of functionally dissimilar species especially in smaller streams. Our findings demonstrate that effects of litter diversity on plant mixture breakdown are more predictable than generally thought. We further argue that the consequences of current worldwide homogenization in the composition of plant traits on carbon and nutrient dynamics could be better inferred from long-duration experiments that manipulate both functional litter diversity and ecosystem characteristics in "hotspots of biodiversity effects," such as small streams. PMID:21560686

Lecerf, Antoine; Marie, Guillaume; Kominoski, John S; LeRoy, Carri J; Bernadet, Caroline; Swan, Christopher M

2011-01-01

78

Time-of-flight characteristics of the conical field: perspectives for application in coincidence spectroscopy  

NASA Astrophysics Data System (ADS)

Cone-like electrostatic potential (Phi) equals 1n[tg((gamma) /2)], where (gamma) is the polar angle of the spherical system of coordinates, is being discussed. It is known to be suitable for energy analysis of flat beams of charged particles emitted from the point source in one plane or close to it. Now, time-of-flight features are examined of the hypothetical energy analyzers based on (Phi) , with an eye to future application of such devices in coincidence electron or ion spectroscopy. It is shown that their temporal characteristics could be several times better than the same values of the cylindrical mirror analyzer (CMA).

Davydov, Sergey N.; Romanov, Sergei N.

1999-05-01

79

Efficient computation for dynamic responses of systems with time-varying characteristics  

NASA Astrophysics Data System (ADS)

Based on Neumman series and epsilon-algorithm, an efficient computation for dynamic responses of systems with arbitrary time-varying characteristics is investigated. Avoiding the calculation for the inverses of the equivalent stiffness matrices in each time step, the computation effort of the proposed method is reduced compared with the full analysis of Newmark method. The validity and applications of the proposed method are illustrated by a 4-DOF spring-mass system with periodical time-varying stiffness properties and a truss structure with arbitrary time-varying lumped mass. It shows that good approximate results can be obtained by the proposed method compared with the responses obtained by the full analysis of Newmark method.

Ma, Liang; Chen, Yudong; Chen, Suhuan; Meng, Guangwei

2009-10-01

80

Effect of Etching Time on the Characteristics of Low Resistivity Porous Si Devices  

NASA Astrophysics Data System (ADS)

In this paper, we report the effect of etching time on the morphological, structural and electrical properties of porous silicon (PSi) synthesized by electrochemical anodization of low resistivity p-type crystalline silicon at current density of 15 mA/cm2. Atomic force microscopy (AFM) measurements showed that the square root of roughness is increased with etching time. Scanning electron microscopy (SEM) investigations revealed that the microstructure of porous silicon is varying with etching time and pores from nano-size to micro-size were formed. Energy dispersive X-ray (EDX) analysis confirmed that the amount of oxygen increases with etching time. Porosity and thickness estimated gravimetrically showed a dependence on the anodization time. The room temperature dark electrical resistivity of porous silicon has observed to be increased with etching time. X-ray photoelectron spectroscopy (XPS) analysis of synthesized porous silicon has shown peaks of C 1s, Si 2p, O 1s, F 1s and N 1s. Current-voltage (I-V) characteristics of synthesized Al/PSi/c-Si junctions prepared at different etching times are investigated and analyzed. The ideality factor, barrier height and built-in potential of porous silicon junctions were strongly found to be dependent on the etching time.

Ismail, Raid A.

2013-12-01

81

Usefulness of precise time stamping for exposing network characteristics on high-speed links  

NASA Astrophysics Data System (ADS)

To expose network characteristics by active/passive measurements, measuring some timing issues such as one-way delay, one-way queuing delay, and inter-packet time is essential, and is conducted by time-stamping for packets passing through an observation point. However, emerging high-speed networks require very high precision of time-stamping, far beyond the precision of conventional software-based time-stamping systems such as 'tcpdump'. For example, the inter-packet time of two consecutive 64-byte length packets on a giga-bit link can be less than 0.001 msec. In this paper, to demonstrate the usefulness and strong necessity of precise time-stamping on high-speed links, experiments of network measurements over a nation-wide IPv6 testbed in Japan have been performed, using a hardware-based time-stamping system that can synchronize to GPS with a high resolution of 0.0001 msec and within a small error of 0.0003 msec. In our experiments, several interesting results are seen, e.g., i) the distribution of one-way queuing delay exhibits a considerable difference depending on the size and the type (UDP/ICMP) of packets; ii) the minimal one-way delays for various sizes of UDP/ICMP packets give an accurate estimate of the transmission delay and the propagation delay; iii) the correlation between interpacket times at the sender and the receiver sides in a sequence of TCP ACK packets clearly shows the degree of ACK compression; iv) the inter-packet time in a UDP stream generated by a DV streaming application shows three dominant sending rates and a very rare peak rate, which might provide crucial information to bandwidth dimensioning; all of which would indicate the usefulness of precise time-stamping.

Kitatsuji, Yoshinori; Tsuru, Masato; Katsuno, Satoshi; Oie, Yuji

2004-10-01

82

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

NASA Astrophysics Data System (ADS)

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.

Peruzza, Laura; Pace, Bruno; Cavallini, Fabio

2010-01-01

83

Multistability of neural networks with time-varying delays and concave-convex characteristics.  

PubMed

In this paper, stability of multiple equilibria of neural networks with time-varying delays and concave-convex characteristics is formulated and studied. Some sufficient conditions are obtained to ensure that an n-neuron neural network with concave-convex characteristics can have a fixed point located in the appointed region. By means of an appropriate partition of the n-dimensional state space, when nonlinear activation functions of an n-neuron neural network are concave or convex in 2k+2m-1 intervals, this neural network can have (2k+2m-1)n equilibrium points. This result can be applied to the multiobjective optimal control and associative memory. In particular, several succinct criteria are given to ascertain multistability of cellular neural networks. These stability conditions are the improvement and extension of the existing stability results in the literature. A numerical example is given to illustrate the theoretical findings via computer simulations. PMID:24808508

Zeng, Zhigang; Zheng, Wei Xing

2012-02-01

84

Spectral and time characteristics of the radiation of a tunable laser with a totally condensed spectrum  

NASA Astrophysics Data System (ADS)

Spectral characteristics and pulse kinetics of a tunable laser under conditions of total spectral condensation (SC) were studied using a resonator device with a BeAl2O4:Cr(3+) (alexandrite) laser, and a cerium plasma torch to elicit the SC effect. The laser pulse kinetics was found to depend on the behavior of the radiation spectrum, indicating that the plasma was affecting not only the spectral, but also the time characteristics of the laser pulse, and that plasma can be used as a mode-locking device as well as a Q-switch of the laser pulse. Similar plasma-effected changes in the pulse kinetics were observed with Al2O3:Ti(3+) and the GSGG:Cr(3+) laser crystals.

Kolerov, A. N.

1986-04-01

85

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

PubMed

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 2-4 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

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

2014-07-01

86

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

NASA Astrophysics Data System (ADS)

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.

Amano, Yoko; Ogasawara, Satoshi

87

Use of a characteristic time scale of microwave emission to determine accumulation variability in Antarctica  

NASA Astrophysics Data System (ADS)

Relationship of the Passive Microwave Characteristic Time Scale of Emission to Accumulation Rate in Antarctica Authors: Lora S. Koenig1, Eric J. Steig1, Dale P. Winebrenner2 1) Department of Earth and Space Sciences, University of Washington 2) Applied Physics Laboratory, University of Washington Passive microwave sensors offer a potential tool for retrieving accumulation rates over the Greenland and Antarctic ice sheets. However, no retrieval method developed to date is reliable in both temporal and spatial domains. A new retrieval method is presented that shows considerable promise. The characteristic timescale of emission (? 0) is the ratio of the microwave extinction length in the firn, squared, to the firn thermal diffusivity. This characteristic time scale arises in a convolution expression that relates physical temperature to microwave brightness temperature, replacing the "emissivity" term in the traditional Rayleigh-Jeans approximation. ? 0 can be estimated for the entire Antarctic continent by comparing thermal infrared observations of physical surface temperature from the AVHRR satellite with passive microwave brightness temperatures at the 37 GHz vertically polarized channel measured by the Scanning Multichannel Microwave Radiometer (SMMR) and Special Senor Microwave Imager (SSM/I). Comparison between ? 0 and independent estimates of accumulation rate from radar-echo-sounding observations near Byrd Station Antarctica shows a strong linear relationship for accumulation rates over a broad range -- from 10 to 50 cm/year ice equivalent. Averaged over the 18 years of available data, ? 0 varies over this area from a few days to more than three months. Estimates of ? 0 over short time intervals of three years show patterns reminiscent of expected accumulation rate variability, and are of the correct magnitude to plausibly relate to temporal accumulation rate changes. Additional radar accumulation measurements from West Antarctica, which provide temporal as well as spatial estimates of accumulation over broad areas, are currently being compared with calculations of ? 0 to further examine the extent to which the observed spatial relationship holds in the temporal domain.

Koenig, L. S.; Steig, E. J.; Winebrenner, D. P.

2004-12-01

88

Characteristics of beam collision timing and position at the KEK B-factory  

NASA Astrophysics Data System (ADS)

Using the Belle detector we study the characteristics of beam collisions at the KEKB 3.5 GeV e+ and 8 GeV e- asymmetric energy collider. We investigate the collision timing tIP and its z-coordinate along the beam axis zIP as a function of the position of the colliding bunch in a beam train. The various tIP and zIP behaviors observed by Belle are attributed to beam loading effects in the radio frequency cavities that accelerate the beams with a beam abort gap. We also discuss the prospects for the Super-KEKB collider.

Kichimi, H.

2010-11-01

89

Time-dependent radiation characteristics of Nannochloropsis oculata during batch culture  

NASA Astrophysics Data System (ADS)

This paper reports the temporal evolution of the scattering and absorbing cross-sections of marine eustigmatophycease Nannochloropsis oculata grown in a flat-plate photobioreactor (PBR). The PBR was operated in batch mode under constant irradiance of 7500 or 10,000 lux provided by red LEDs emitting at 630 nm. The radiation characteristics between 400 and 750 nm and pigment concentrations of N. oculata were measured systematically every 24 h for up to 18 days. They were found to vary significantly with time in response to changes in light and nutrients availability. The results were interpreted in terms of up- and down-regulations of pigments and other intracellular components. Finally, this study demonstrates that the light transfer in the PBR could be predicted using constant radiation characteristics measured during the exponential growth phase with reasonable accuracy provided that the cultures were not nitrogen limited. During nitrogen starvation, pigment concentrations decreased and radiation characteristics evolved rapidly. These results will be useful in the design and operation of PBRs for biofuel production at both small and large scales.

Heng, Ri-Liang; Pilon, Laurent

2014-09-01

90

Transient Stability Analysis of Induction Generator Using Time Domain Torque Characteristic  

NASA Astrophysics Data System (ADS)

Transient stability assessment of the wind power generator is one of main issue in power system security and operation. The transient stability of the wind power generator is determine by its corresponding Critical Clearing Time(CCT). In this paper, we present the formulae to the transient behavior analysis and the transient stability analysis technique of induction generator used in wind power generating system at the three-phase fault condition. In the proposed method, the transient stability of the induction generator is analyzed using well known torque-slip and generator speed-time characteristics. The validity of the developed technique is confirmed with the results obtained from trials and error method using MATLAB/SIMULINK.

Senjyu, Tomonobu; Sueyoshi, Norihide; Uezato, Katsumi; Fujita, Hideki; Funabashi, Toshihisa

91

A prospective cohort study of menstrual characteristics and time to pregnancy.  

PubMed

The authors examined the association between menstrual characteristics and time to pregnancy among 2,653 Danish women enrolled in a prospective cohort study (2007-2009). Menstrual characteristics were reported at baseline. Outcome data were updated bimonthly until pregnancy, fertility treatment, loss to follow-up, or end of observation (12 cycles). Adjusted fecundability ratios and 95% confidence intervals were estimated by using discrete-time Cox regression models. Relative to average cycle lengths (27-29 days), fecundability ratios for cycle lengths <25, 25-26, 30-31, 32-33, and ?34 days were 0.64 (95% confidence interval (CI): 0.49, 0.84), 0.94 (95% CI: 0.77, 1.13), 1.10 (95% CI: 0.97, 1.25), 1.35 (95% CI: 1.06, 1.73), and 1.17 (95% CI: 0.91, 1.49), respectively. Compared with cycles that regularized within 2 years after menarche, fecundability ratios for cycles that regularized 2-3 and ?4 years after menarche were 0.90 (95% CI: 0.80, 1.02) and 0.89 (95% CI: 0.77, 1.03), respectively. Fecundability ratios were 0.87 (95% CI: 0.72, 1.05) comparing <3 with 3-4 days of menstrual bleeding and 0.70 (95% CI: 0.43, 1.13) comparing very heavy with moderate flow. In the present study, shorter cycle length was associated with delayed time to pregnancy. Age at menarche, time to menstrual regularization, and duration or intensity of menstrual flow were not appreciably associated with fecundability. PMID:21719742

Wise, Lauren A; Mikkelsen, Ellen M; Rothman, Kenneth J; Riis, Anders H; Sørensen, Henrik Toft; Huybrechts, Krista F; Hatch, Elizabeth E

2011-09-15

92

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

PubMed Central

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 Tukey’s 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 (4–8 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.

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

2012-01-01

93

Discharge time dependence of a solution plasma process for colloidal copper nanoparticle synthesis and particle characteristics  

NASA Astrophysics Data System (ADS)

In this study, we investigate a new synthetic route, termed the solution plasma process, for the synthesis of colloidal copper nanoparticles (CuNPs) in the presence of an amide and acid capping agent. Gelatin and ascorbic acid were selected as the capping agents to protect the particles against coalescence and oxidation side reaction. Using a high voltage power supply, CuNPs were rapidly formed by 1 min after the discharge. The size and shape of the CuNPs were dependent on the discharge time and were clearly influenced by the effect of the capping agents under two characteristics of the discharge medium (pH and temperature). With a long discharge time, the CuNP size tended to decrease with the formation of anisotropic particle morphologies: spherical, cubic, hexagonal, triangular and rod-like shapes. The decrease in CuNP size as a function of discharge time could be explained by the dissolution of CuNPs in a lower pH solution. After 5 min discharge the capping agent evidently allowed the protection of the synthesized CuNPs against oxidation with the presence of anisotropic CuNP shapes. It is demonstrated that the CuNP shape could be tuned from spherical to anisotropic shapes without the undesirable oxidation by adjusting the discharge time of the solution plasma. These advantages are valuable for material engineering to design the properties of Cu-based nanoparticles for the desired applications.

Pootawang, Panuphong; Saito, Nagahiro; Lee, Sang Yul

2013-02-01

94

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

SciTech Connect

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)

Hoffman, A. J.; Lee, J. C. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI, 48109-2104 (United States)] [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI, 48109-2104 (United States)

2013-07-01

95

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

NASA Astrophysics Data System (ADS)

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.

Gebremichael, Mekonnen

96

Observed spatiotemporal characteristics of drought on various time scales over the Czech Republic  

NASA Astrophysics Data System (ADS)

This paper analyses the observed spatiotemporal characteristics of drought in the Czech Republic during the growing season (April to September) as quantified using the Standardised Precipitation Evapotranspiration Index (SPEI) on various time scales. The SPEI was calculated for various lags (1, 3, 6, 12, and 24 months) from monthly records of mean temperature and precipitation totals using a dense network of 184 climatological stations for the period 1961-2010. The characteristics of drought were analysed in terms of the temporal evolution of the SPEI, the frequency distribution and duration of drought at the country level, and for three regions delimited by station altitude. The driest and the wettest years during the growing season were identified. The frequency distribution of the SPEI values for seven drought category classes (in per cent) indicates that normal moisture conditions represent approximately 65 % of the total SPEI values for all time scales in all three regions, whereas moderate drought and moderate wet conditions are almost equally distributed around 10.5 %. Differences in extremely dry conditions (5 %) compared with extremely wet conditions (1.5 %) were observed with increasing SPEI time scales. The results of the non-parametric Mann-Kendall trend test applied to the SPEI series indicate prevailing negative trends (drought) at the majority of the stations. The percentage of stations displaying a significant negative trend for the 90, 95, 99, and 99.9 % confidence levels is approximately 40 %. An Empirical Orthogonal Functions (EOF) analysis was used to identify the principal patterns of variability of the SPEI during the growing season that accounted for the highest amount of statistical variance. The variance explained by the leading EOF range 66 to 56 %, whereas for EOF2 and EOF3, the value is between 7 and 11 % and between 4 and 7 %, respectively, for the SPEI is calculated for 1- to 24-month lags.

Potop, Vera; Boronean?, Constan?a; Možný, Martin; Št?pánek, Petr; Skalák, Petr

2013-05-01

97

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

PubMed Central

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

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

1993-01-01

98

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

PubMed Central

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.

Liu, Jiming; Tao, Li; Xiao, Bo

2011-01-01

99

Turbulent transport, characteristic length and time scales above and within the BEMA forest site at Castelporziano  

NASA Astrophysics Data System (ADS)

Turbulent transport characteristics were determined above and inside the BEMA-forest to estimate the time and length scales for the diffusive transport of trace constituents like VOCs between the canopy and the atmosphere. The Eulerian ( ?T) and Lagrangian ( ?L) time scales for turbulent transport in the crown region during neutral to unstable conditions are found to be less than 10 2 s. Inside the canopy for heights below z/ hc = 0.9 during free convective conditions with small u ? (and u ? < w ?), ?T and ?L increased up to 2 × 10 2-6 × 10 2 s. When mechanical turbulence caused more intensive mixing ( u ? > w ?) also down to the trunk space atmosphere, values of about ?T ? 2 × 10 2 were determined for z/ hc < 0.9. Time scales ?crt for chemical reactions of VOC with radicals (OH, NO 3) mostly fulfil the relation ?crt > ?T, ?L for compounds emitted from the crown. Only for ?T > 2 × 10 2 the relation ?crt ? ?T holds for some compounds in the lower canopy and an influence of chemical reactions on the net VOC flux to the atmosphere can be expected.

Zelger, Michael; Schween, Jan; Reuder, Jochen; Gori, Tullio; Simmerl, Karin; Dlugi, Ralph

100

Time-variable Earth's albedo model characteristics and applications to satellite sampling errors  

NASA Technical Reports Server (NTRS)

Characteristics of the time variable Earth albedo model are described. With the cloud cover multiplying factor adjusted to produce a global annual average albedo of 30.3, the global annual average cloud cover is 45.5 percent. Global annual average sunlit cloud cover is 48.5 percent; nighttime cloud cover is 42.7 percent. Month-to-month global average albedo is almost sinusoidal with maxima in June and December and minima in April and October. Month-to-month variation of sunlit cloud cover is similar, but not in all details. The diurnal variation of global albedo is greatest from November to March; the corresponding variation of sunlit cloud cover is greatest from May to October. Annual average zonal albedos and monthly average zonal albedos are in good agreement with satellite-measured values, with notable differences in the polar regions in some months and at 15 S. The albedo of some 10 deg by 10 deg. areas of the Earth versus zenith angle are described. Satellite albedo measurement sampling effects are described in local time and in Greenwich mean time.

Bartman, F. L.

1981-01-01

101

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

PubMed

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

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

2012-12-01

102

The Advantage of Arriving First: Characteristic Times in Finite Size Populations of Error-Prone Replicators  

PubMed Central

We study the evolution of a finite size population formed by mutationally isolated lineages of error-prone replicators in a two-peak fitness landscape. Computer simulations are performed to gain a stochastic description of the system dynamics. More specifically, for different population sizes, we compute the probability of each lineage being selected in terms of their mutation rates and the amplification factors of the fittest phenotypes. We interpret the results as the compromise between the characteristic time a lineage takes to reach its fittest phenotype by crossing the neutral valley and the selective value of the sequences that form the lineages. A main conclusion is drawn: for finite population sizes, the survival probability of the lineage that arrives first to the fittest phenotype rises significantly.

Marin, Arturo; Tejero, Hector; Nuno, Juan Carlos; Montero, Francisco

2013-01-01

103

Characteristics and performance of aerobic granular sludge treating rubber wastewater at different hydraulic retention time.  

PubMed

The influence of hydraulic retention time (HRT, 24, 12, and 6h) on the physical characteristics of granules and performance of a sequencing batch reactor (SBR) treating rubber wastewater was investigated. Results showed larger granular sludge formation at HRT of 6h with a mean size of 2.0±0.1mm, sludge volume index of 20.1mLg(-1), settling velocity of 61mh(-1), density of 78.2gL(-1) and integrity coefficient of 9.54. Scanning electron microscope analyses revealed different morphology of microorganisms and structural features of granules when operated at various HRT. The results also demonstrated that up to 98.4% COD reduction was achieved when the reactor was operated at low HRT (6h). Around 92.7% and 89.5% removal efficiency was noted for ammonia and total nitrogen in the granular SBR system during the treatment of rubber wastewater. PMID:24704837

Rosman, Noor Hasyimah; Nor Anuar, Aznah; Chelliapan, Shreeshivadasan; Md Din, Mohd Fadhil; Ujang, Zaini

2014-06-01

104

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

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

105

Summer-time thermal environment characteristics in central Korea using Landsat TM data  

NASA Astrophysics Data System (ADS)

Urban heat island(UHI) effect is the temperature increase in urban areas compared to that in surrounding rural areas and is caused by a number of factors, such as land use / land cover (LULC)change, increase fuel consumption and lack of vegetation in urban core areas. The replacement of natural surface types from soil and vegetation to impervious materials such as asphalt and concrete structures affects the albedo and runoff characteristics of the urban land surface. The impervious materials have a lower albedo than soil and vegetation and hold more solar energy, which increase land surface temperature (LST) during the summer season. UHI effects on the center region of South Korea were analyzed using remotely sensed data. The objectives of this study are to examine the summer-time thermal environment of the Cheongju city in Korea, review the satellite assessment of the thermal environment of LULC, and compare thermal environment in 1991 to 2006. Chang detection of thermal environment is performed to determine whether a significant change has occurred. The average of LST of study area has increased 2.7°C during 15years because of changed land cover from paddy field and forest to barren, factory, and concrete. This case study indicates that barren, factory, and residential apartment over on the Cheongju and Ochang increased in the late 1990s and that vegetation area are changing predominantly in the direction of decreased forest and paddy fields. Decreasing forest and paddy fields are an important result, as it suggests that directional changes are occurring on the Cheongju and Ochang that are consistent with experimental urban warming. The most influential factors for controlling the summer-time thermal environment are the distribution of surface cover characteristics (e.g. LULC) and urban morphology, such as urban consistence materials, geometry, development stage, and density.

Park, Jin-Ki; Park, Jong-Hwa; Na, Sang-Il

2010-10-01

106

Determinants of Timely Completion: The Impact of Bachelor's Degree Programme Characteristics and Student Motivation on Study Progress  

ERIC Educational Resources Information Center

Timely completion of university degree programmes is a topic of growing concern to higher education institutions and their students. This paper reports on a study about the impact of degree programme characteristics and student motivation on study progress. The setting for the study is a Dutch law school. Data on degree programme characteristics,…

Suhre, Cor J. M.; Jansen, Ellen P. W. A.; Torenbeek, M.

2013-01-01

107

Influence of age and aerobic fitness on the multifractal characteristics of electrocardiographic RR time-series  

PubMed Central

Multifractal properties of electrocardiographic inter-beat (RR) time-series offer insight into its long-term correlation structure, independently of RR variability. Here we quantify multifractal characteristics of RR data during 24-h diurnal-nocturnal activity in healthy participants. We tested the hypotheses that (1) age, gender and aerobic fitness influence RR multifractal properties, and that (2) these are influenced by circadian variation. Seventy adults (39 males) aged 19–58 years and of various fitness levels were monitored using 24-h ECG. Participants were dichotomized by median age and fitness for sub-group analysis. Gender and fitness were independent of age (p = 0.1, p > 0.5). Younger/older group ages were substantially different (p < 0.0005) and were independent of gender and fitness. Multifractality was quantified using the probability spectrum of Hölder exponents (h), from which modal h (h*) and the full-width and half-widths at half-maximum measures (FWHM, HWHM+, and HWHM?) were derived. FWHM decreased (p = 0.004) and h* increased (p = 0.011) in older people, indicating diminished long-range RR correlations and weaker anti-persistent behavior. Anti-persistent correlation (h*) was strongest in the youngest/fittest individuals and weakest in the oldest/least fit individuals (p = 0.015). Long-range correlation (HWHM+/FWHM) was strongest in the fittest males and weakest in the least fit females (p = 0.007–0.033). Multifractal RR characteristics in our healthy participants showed strong age-dependence, with diminished long-range anti-persistent correlation in older people. Circadian variation of these characteristics was influenced by fitness and gender: fitter males and females of all ages had the greatest degree of multifractality or long-range order. Multifractal characterization appears to be a useful method for exploring the physiological basis of long-term correlation structure in RR time-series as well as the benefits thereon of physical fitness training.

Lewis, Michael J.; McNarry, Melitta A.

2013-01-01

108

Evaluation of Frequency Characteristics of Absorbing Materials Using Time-Domain Single Antenna Method at Standard Site  

Microsoft Academic Search

Frequency characteristics of absorbing materials are evaluated in single-antenna calibration technique using a log- periodic antenna on a standard ground plane. The technique is applied to the data both in frequency- and time-domains, to evaluate the frequency characteristics of absorbing materials on the ground plane. Time-domain subtraction enables us to separate the wave reflected from absorbing materials. As a result,

Satoru Kurokawa; Masanobu Hirose; Koji Komiyama

2007-01-01

109

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

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

110

Evaluation of night-time pain characteristics and quality of sleep in postoperative Turkish orthopedic patients.  

PubMed

This descriptive, correlational study was conducted to determine orthopedic patients' night-time pain characteristics, their quality of sleep and the contributing factors to poor sleep experiences, and the relationship between pain and sleep. Data were collected by using the McGill Pain Questionnaire-SF (MPQ-SF) and Pittsburgh Sleep Quality Index (PSQI) on the second postoperative day. Data were analyzed using the SPSS version 10.0 for Windows. Mean age of the 75 patients was 49.55 ± 21.10 years and were hospitalized in the orthopedic wards for 10.56 ± 14.74 days. Of the sample, 65.3% were female and 36% had hip/knee arthroplasty surgery. Pain (45%) and noise (23%) were found to be the most cited factors affecting the sleep of patients in postoperative periods. They experienced "external" pain at the surgical site and verbalized their pain as "stabbing" and "tiring-exhausting." Patients' night-time pain was determined to be severe (6.59 ± 1.62); their quality of sleep was also poor (9.24 ± 3.53). A statistically significant correlation was found between patients' pain intensity and quality of sleep (p?.05). PMID:21521827

Büyükyilmaz, Funda Esen; ?endir, Merdiye; Acaro?lu, Rengin

2011-08-01

111

Using centroid time-delays to characterize source durations and identify earthquakes with unique characteristics  

NASA Astrophysics Data System (ADS)

The relationship between M0 and the rupture duration is often difficult to establish. This is particularly true for large earthquakes for which the moment rate functions (MRF) generally have complicated shapes, and the estimated durations can vary considerably depending on the methodology used to evaluate the MRF. In this work, we show that the centroid time-delay (?c) provides an alternative estimate of the source duration. Inverted MRFs often end gradually, making the end of coseismic rupture difficult to detect. In such cases, when the rupture duration is not well defined, the time-delay ?c is a useful quantity to represent the first-order temporal characteristics of the rupture process. Variations in stress parameter ?? can be investigated by assuming a standard scaling relationship between the seismic moment M0 and ?c. This simple scaling relationship can also be used to identify unusual earthquakes, with unique source properties, such as events involving complicated rupture processes or earthquakes characterized by unusual rupture velocities, stress drops or aspect ratios.

Duputel, Zacharie; Tsai, Victor C.; Rivera, Luis; Kanamori, Hiroo

2013-07-01

112

Comparison of sporadic sodium layer characteristics observed at different time resolutions  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

113

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

NASA Technical Reports Server (NTRS)

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.

Lo, C. C.; Leskovar, B.

1976-01-01

114

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

PubMed Central

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.

2013-01-01

115

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

PubMed

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

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

2014-05-21

116

Timing characteristics of a Cd1-xZnxTe detector-based X-ray imaging system  

Microsoft Academic Search

The timing characteristics of a planar Cd1-xZnx Te sample at each frequency of a scanning square-wave test pattern, has been measured. This study is aimed at evaluating the speed characteristics of a Cd1-xZnxTe detector for X-ray imaging and computed tomographic (CT) applications. The experimental results of this study indicate that the temporal response of a Cd1-xZnxTe detector based X-ray system,

George C. Giakos; S. Vedantham; S. Chowdhury; J. Odogba; A. Dasgupta; R. Guntupalli; S. Suryanarayanan; V. Vega-Lozada; M. Sridhar; M. Khyati; N. Shah

1999-01-01

117

Modal and characteristics-based approaches for modeling elastic waves induced by time-dependent boundary conditions  

NASA Astrophysics Data System (ADS)

In this paper, we present a characteristics-based approach for solving elastic wave problems with time-dependent traction boundary conditions. A generalized mathematical model for this important class of problems is expressed as a set of first-order, linear, hyperbolic partial differential equations. We analyze the mathematical structure of this first-order linear system, verify its hyperbolicity, derive its characteristic form, and deduce its eigenvalues, eigenvectors, and Riemann invariants. The eigenvalues correspond to the wave speeds, while the Riemann invariants are used to construct a solution by the method of characteristics.

Lowe, Robert L.; John Yu, Sheng-Tao; Yang, Lixiang; Bechtel, Stephen E.

2014-02-01

118

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

119

Clinicopathologic Characteristics of Gastric Cancer Patients according to the Timing of the Recurrence after Curative Surgery  

PubMed Central

Purpose There are few studies that have focused on the predictors of recurrence after gastrectomy for gastric carcinoma. This study analyzed the patients who died of recurrent gastric carcinoma and we attempted to clarify the clinicopathologic factors that are associated with the timing of recurrence. Materials and Methods From June 1992 to March 2009, 1,795 patients underwent curative gastric resection at the Department of Surgery, Hanyang University College of Medicine. Among them, 428 patients died and 311 of these patients who died of recurrent gastric carcinoma were enrolled in this study. The clinicopathologic findings were compared between the 72 patients who died within one year after curative gastrectomy (the early recurrence group) and the 92 patients who died 3 years after curative gastrectomy (the late recurrence group). Results Compared with the late recurrence group, the early recurrence group showed an older age, a more advanced stage, a poorly differentiated type of cancer and a significantly higher tendency to have lymphatic invasion, vascular invasion and perineural invasion.Especially in the gastric cancer patients with a more advanced stage (stage III and IV), the early recurrence group was characterized by a significantly higher preoperative serum carcino embryonic antigen level, perineural invasion and a relatively small number of dissected lymph nodes. Conclusions The clinicopathologic characteristics of recurrent gastric cancer are significantly different according to the stage of disease, and even in the same stage. For the early detection of recurrence after curative surgery, it is important to recognize the clinicopathological factors that foretell a high risk of recurrence. It is mandatory to make an individualized surveillance schedule according to the clinicopathologic factors.

Choi, Ji Yoon; Ha, Tae Kyung

2011-01-01

120

Characteristic recovery times of Forbush-type decreases in the cosmic radiation: 1. Observations at earth at different energies  

SciTech Connect

About 30 Forbush-type decreases occurring from 1972 at 1 AU for which data were available from the IMP spacecraft (P median of approx.1.7 GV) and the Mt. Washington neutron monitor (P median of approx.5 GV) were examined to determine the characteristic recovery times of the events. The characteristic recovery time t/sub 0/ was found to be the same for rigidities of approx.1.7 GV and approx.5.0 GV. Characteristic recovery times for additional Forbush decreases, including some in 1957-1963, were determined, using the Mt. Washington neutron monitor and monitors at cutoff rigidities of approx.12 GV, ans were also found to be the same. Hence the characteristic recovery time of Forbush decreases at 1 AU is independent of energy (or rigidity) over a factor of at least 10. The average recovery time t/sub 0/ at 1 AU is approx.5 days but varies from approx.3 to approx.10 days, and the recovery in most cases is well represented by an exponential. No significant difference in the average recovery time is observed when the solar magnetic field reversed in 1980 nor during the decrease and recovery portion of the solar modulation cycle. A physical model is proposed to explain these results.

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

1986-03-01

121

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

SciTech Connect

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.

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

2008-06-01

122

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

NASA Astrophysics Data System (ADS)

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).

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

2013-12-01

123

Influence of the averaging time on the quality of reconstruction of small-scale wind turbulence characteristics in acoustic sounding  

NASA Astrophysics Data System (ADS)

Influence of the averaging period on the quality of reconstruction of the wind velocity structure functions and characteristics from the data of minisodar measurements is investigated. Values of the structure functions and characteristics averaged over 10, 20, 25, 30, and 60-min periods are presented. Results of their calculations using an original algorithm demonstrate that the structure characteristic decreases with increasing averaging time. Thus, for the 10-min averaging period, the velocity structure characteristic calculated for one series of minisodar measurements was 0.00376 m4/3/s2 for sounding altitude of 100 m; it significantly decreased (by 37%) for the 20-min averaging period, and decreased by less than 5% for the 25-min averaging period. This allows us to recommend the 20-min averaging period as optimal one for investigation of the dynamics of smallscale wind turbulence using acoustic sounding.

Kapegesheva, O. F.; Krasnenko, N. P.; Stafeev, P. G.; Shamanaeva, L. G.

2013-03-01

124

Operational characteristic analysis of conduction cooling HTS SMES for Real Time Digital Simulator based power quality enhancement simulation  

NASA Astrophysics Data System (ADS)

This paper analyzes the operational characteristics of conduction cooling Superconducting Magnetic Energy Storage (SMES) through a real hardware based simulation. To analyze the operational characteristics, the authors manufactured a small-scale toroidal-type SMES and implemented a Real Time Digital Simulator (RTDS) based power quality enhancement simulation. The method can consider not only electrical characteristics such as inductance and current but also temperature characteristic by using the real SMES system. In order to prove the effectiveness of the proposed method, a voltage sag compensation simulation has been implemented using the RTDS connected with the High Temperature Superconducting (HTS) model coil and DC/DC converter system, and the simulation results are discussed in detail.

Kim, A. R.; Kim, G. H.; Kim, K. M.; Kim, D. W.; Park, M.; Yu, I. K.; Kim, S. H.; Sim, K.; Sohn, M. H.; Seong, K. C.

2010-11-01

125

The Research of Static Var Compensator's Time Characteristics and System-level Model of Controlled Current Source  

NASA Astrophysics Data System (ADS)

In the status of lacking research on response time of static var compensator (SVC), this paper established the controlled current source model which can achieve the same effect in response time and reactive compensation with the physical model of SVC by analyzing of characteristics in reactive power compensation and the response of the static var compensator (SVC) physical model. Through the time module in control signal of controlled current source, it can accurately calculate the response time of SVC. It tested the consistency of two models through the simulation of a rolling mill start experiment in PSCAD.

Zhang, Chao; Jiang, Qi-rong; Sun, Shou-xin

126

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

PubMed Central

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.

Ram, Nilam; Gerstorf, Denis

2009-01-01

127

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

128

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

SciTech Connect

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.

Shutov, A. V.; Smetanin, I. V.; Ionin, A. A.; Levchenko, A. O.; Seleznev, L. V.; Sinitsyn, D. V.; Ustinovskii, N. N.; Zvorykin, V. D. [P. N. Lebedev Physical Institute, Leninskii Prospect 53, Moscow 119991 (Russian Federation)

2013-07-15

129

Comparison of the Operational Characteristics of the Theory of Constraints and Just-In-Time Scheduling Methodologies.  

National Technical Information Service (NTIS)

This study compared the characteristics of scheduling using two approaches: Just-in-Time (JIT) and the Theory of Constraints (TOC). Computer simulation was used to evaluate changes in the throughput of the system due to system variability and varying work...

L. A. Sines

1991-01-01

130

Characteristics and behaviors of soluble microbial products in sequencing batch membrane bioreactors at various sludge retention times  

Microsoft Academic Search

The characteristics and behaviors of soluble microbial products (SMP) in sequencing batch membrane bioreactors (SBMBRs) were investigated at various sludge retention times (SRTs). SMP concentrations in SBMBRs reached a minimum at SRT of 40 days and were consistently higher than those in effluents. The extent of SMP accumulation was found to significantly increase with decreasing SRT. Similar molecular weight distributions

Bin Dong; Shuangying Jiang

2009-01-01

131

Estimating and comparing time-dependent areas under receiver operating characteristic curves for censored event times with competing risks.  

PubMed

The area under the time-dependent ROC curve (AUC) may be used to quantify the ability of a marker to predict the onset of a clinical outcome in the future. For survival analysis with competing risks, two alternative definitions of the specificity may be proposed depending of the way to deal with subjects who undergo the competing events. In this work, we propose nonparametric inverse probability of censoring weighting estimators of the AUC corresponding to these two definitions, and we study their asymptotic properties. We derive confidence intervals and test statistics for the equality of the AUCs obtained with two markers measured on the same subjects. A simulation study is performed to investigate the finite sample behaviour of the test and the confidence intervals. The method is applied to the French cohort PAQUID to compare the abilities of two psychometric tests to predict dementia onset in the elderly accounting for death without dementia competing risk. The 'timeROC' R package is provided to make the methodology easily usable. PMID:24027076

Blanche, Paul; Dartigues, Jean-François; Jacqmin-Gadda, Hélène

2013-12-30

132

Characteristic fringe function for time-average holography of periodic nonsinusoidal vibrations  

Microsoft Academic Search

In this paper the characteristic fringe function of hologram interferometry has been evaluated for the case of periodic, nonsinusoidal vibrations represented by a Jacobian elliptic function. To consider the reconstructed holographic image of an object, use has been made of an equation derived from considerations of the effect of motion on coherence. Graphical representation of the fringe irradiance distribution in

P. C. Gupta; K. Singh

1975-01-01

133

Characteristic Time of the Magnetospheric Ring Current Decay FROM EXPIREMENT AND THEORY  

Microsoft Academic Search

The magnetospheric ring current particles are the most dynamic part of the Earth's radiation belts especially during geomagnetic storms. The processes of the magnetospheric ring current decay are studied as a function of the solar wind electric field. It is shown that the ring current dissipation rate is different during the main and recovery phase of geomagnetic storms. The characteristic

G. I. Korotova

2006-01-01

134

Modeling of EEG Signal Sound Frequency Characteristic Using Time Frequency Analysis  

Microsoft Academic Search

This paper presents the study of sound frequency characteristic based on Electroencephalography (EEG) signals. The study includes feature extraction of the EEG signals with respect to different sound frequencies, covering low frequency (40 Hz), mid-range frequency (5000 Hz), and high frequency (15000 Hz). Human brain activities are expected to be different when exposed to different sound frequencies, and can be

R. Sudirman; A. K. Chee; W. B. Daud

2010-01-01

135

Computing Quantitative Characteristics of Finite-State Real-Time Systems.  

National Technical Information Service (NTIS)

Current methods for verifying real-time systems are essentially decision procedures that establish whether the system model satisfies a given specification. We present a general method for computing quantitative information about finite-state real-time sy...

S. Campos E. Clarke W. Marrero M. Minea

1994-01-01

136

Development and evaluation of mathematical model to predict disintegration time of fast disintegrating tablets using powder characteristics.  

PubMed

The objective of the study was to develop a mathematical model for predicting the disintegration time of fast disintegrating tablets (FDTs) by estimating the powder characteristics of powder blend prior to compression. A combination of chitosan-alginate complex and glycine in the ratio of 50:50 was used for preparing FDTs. The developed mathematical model allowed water sorption time (WST), effective pore radius (R(eff.p)) and swelling Index (SI) of powder mixture as well as tablet crushing strength to be successfully correlated with disintegration time (DT) of FDTs. The predicted model showed that disintegration time of FDTs to be directly correlated with powder characteristics and inversely correlated with tablet crushing strength. Furthermore, a correlation of 0.97 was obtained when DT of FDTs was compared with SI/(WST * R(eff.p)). This correlation was not affected by inclusion of water soluble (ondansetron hydrochloride or metaclopramide hydrochloride) or water insoluble (domperidone) drugs in the powder blend or FDTs. These observations indicated the versatility of the mathematical model in predicting the disintegration time of FDTs by evaluating the selected characteristics of the powder blends without actually preparing the FDTs. PMID:20028210

Goel, H; Arora, A; Tiwary, A K; Rana, V

2011-02-01

137

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

NASA Astrophysics Data System (ADS)

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.

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

2009-06-01

138

A Comparison of Anthropometric and Training Characteristics between Female and Male Half-Marathoners and the Relationship to Race Time  

PubMed Central

Purpose Lower limb skin-fold thicknesses have been differentially associated with sex in elite runners. Front thigh and medial calf skin-fold appear to be related to 1,500m and 10,000m time in men but 400m time in women. The aim of the present study was to compare anthropometric and training characteristics in recreational female and male half-marathoners. Methods The association between both anthropometry and training characteristics and race time was investigated in 83 female and 147 male recreational half marathoners using bi- and multi-variate analyses. Results In men, body fat percentage (?=0.6), running speed during training (?=-3.7), and body mass index (?=1.9) were related to half-marathon race time after multi-variate analysis. After exclusion of body mass index, r2 decreased from 0.51 to 0.49, but body fat percentage (?=0.8) and running speed during training (?=-4.1) remained predictive. In women, body fat percentage (?=0.75) and speed during training (?=-6.5) were related to race time (r2=0.73). For women, the exclusion of body mass index had no consequence on the predictive variables for half-marathon race time. Conclusion To summarize, in both female and male recreational half-marathoners, both body fat percentage and running speed during training sessions were related to half-marathon race times when corrected with co-variates after multi-variate regression analyses.

Friedrich, Miriam; Rust, Christoph A.; Rosemann, Thomas; Knechtle, Patrizia; Barandun, Ursula; Lepers, Romuald; Knechtle, Beat

2013-01-01

139

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)

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.

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

2011-06-01

140

Characteristics and optimal miter of microstrip bend via the finite difference time domain method  

Microsoft Academic Search

A 3D finite difference time domain (FDTD) simulation software was developed. The visual electric field distribution and the voltage signals in time domain of the microstrip bends with different miters are obtained based on the electromagnetic field information provided by FDTD simulation. The relation of the reflection parameter versus miter size and frequency by curve fitting reveals that the optimal

Jianbo Mao; Mingwu Yang; Huaguo Liang; Jinxian Liu; Meng Zhang

2009-01-01

141

Employment status and high blood pressure in women: Variations by time and by sociodemographic characteristics  

Microsoft Academic Search

PURPOSE: The association between employment status and high blood pressure in women was examined at two time periods to determine if associations between employment status and high blood pressure varied by time period or by age, race, education, marital status, or parental status.METHODS: Women participants from the National Health Examination Survey (1960) and the Second National Health and Nutrition Survey

Kathryn M. Rose; Beth Newman; Trude Bennett; Herman A. Tyroler

1997-01-01

142

Characteristics of the Time-Series Data Collected through Curriculum-Based Reading Measurement.  

ERIC Educational Resources Information Center

Research on the analysis of time-series data has shown that decisions reached through visual analysis of the data may be influenced by the statistical parameters of those data. The current study investigated the statistical properties of curriculum-based time-series data for 68 elementary resource room students in four Minnesota school districts.…

Skiba, Russell; And Others

143

An anomaly in space-time characteristics of certain programs running in a paging machine  

Microsoft Academic Search

The running time of programs in a paging machine generally increases as the store in which programs are constrained to run decreases. Experiment, however, have revealed cases in which the reverse is true: a decrease in the size of the store is accompanied by a decrease in running time.An informal discussion of the anomalous behavior is given, and for the

Laszlo A. Belady; Robert A. Nelson; Gerald S. Shedler

1969-01-01

144

A Novel Autofocusing Approach for Real-Time Through-Wall Imaging Under Unknown Wall Characteristics  

Microsoft Academic Search

A novel real-time through-wall imaging (TWI) algorithm with autofocusing ability in the presence of wall ambiguities is proposed in this paper. The spectrum Green's function is employed to formulate the TWI algorithm, where the fast Fourier transform can be used to reconstruct the image in a very short computation time. The complex scattering process due to the presence of the

Lianlin Li; Wenji Zhang; Fang Li

2010-01-01

145

Transitions and interactions of inviscid\\/viscous, compressible\\/incompressible and laminar\\/turbulent flows  

Microsoft Academic Search

This paper addresses the flow field-dependent variation (FDV) methods in which complex physical phenomena are taken into account in the final form of partial differential equations to be solved so that finite difference methods (FDM) or finite element methods (FEM) themselves will not dictate the physics, but rather they are no more than simply the options how to discretize between

T. J. Chung

1999-01-01

146

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

NASA Technical Reports Server (NTRS)

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.

Bippes, H.

1978-01-01

147

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

148

The role of laminar-turbulent transition in gas turbine engines: A discussion  

SciTech Connect

An extended discussion of Mayle's critical study of transition phenomena in gas turbine engines is presented. Attention is focused on transition in decelerating flow regions, which are the major sources of loss production for axial turbomachine blades. The following points are examined in detail: (a) the physics of transition and its implications for the correlation of various transition phenomena; (b) the relative importance of pressure gradient and free-stream turbulence in controlling transition; (c) the influence of pressure gradient on periodic-unsteady transition; (d) the correlation of transition length under conditions of arbitrary pressure gradient and free-stream turbulence level; and (e) transition behavior in laminar separation bubbles. The discussion examines various differences in philosophy concerning the above phenomena and makes further suggestions for transition research, which may assist in resolving the issues raised.

Walker, G.J. (Univ. of Tasmania, Hobart (Australia))

1993-04-01

149

Characteristic time-stepping or local preconditioning of the Euler equations  

NASA Technical Reports Server (NTRS)

A derivation is presented of a local preconditioning matrix for multidimensional Euler equations, that reduces the spread of the characteristic speeds to the lowest attainable value. Numerical experiments with this preconditioning matrix are applied to an explicit upwind discretization of the two-dimensional Euler equations, showing that this matrix significantly increases the rate of convergence to a steady solution. It is predicted that local preconditioning will also simplify convergence-acceleration boundary procedures such as the Karni (1991) procedure for the far field and the Mazaheri and Roe (1991) procedure for a solid wall.

Van Leer, Bram; Lee, Wen-Tzong; Roe, Philip L.

1991-01-01

150

Characteristic time-stepping or local preconditioning of the Euler equations  

NASA Astrophysics Data System (ADS)

A derivation is presented of a local preconditioning matrix for multidimensional Euler equations, that reduces the spread of the characteristic speeds to the lowest attainable value. Numerical experiments with this preconditioning matrix are applied to an explicit upwind discretization of the two-dimensional Euler equations, showing that this matrix significantly increases the rate of convergence to a steady solution. It is predicted that local preconditioning will also simplify convergence-acceleration boundary procedures such as the Karni (1991) procedure for the far field and the Mazaheri and Roe (1991) procedure for a solid wall.

van Leer, Bram; Lee, Wen-Tzong; Roe, Philip L.

151

Investigations as to the Noise Characteristics of GaAs Avalanche Transit Time Diode Oscillators.  

National Technical Information Service (NTIS)

Gallium arsenide p-n junction avalanche transit time oscillators were characterized with respect to noise performance. The results of these measurements were compared to other p-n junction oscillators, Read diodes, and Gunn diodes. Measurements include: r...

J. J. Baranowski V. J. Higgins

1970-01-01

152

Time-domain finite difference approach to the calculation of the frequency-dependent characteristics of microstrip discontinuities  

Microsoft Academic Search

The frequency-dependent characteristics of the microstrip discontinuities have previously been analyzed using full-wave approaches. The time-domain finite-difference (TD-FD) method presented here is an independent approach and is relatively new in its application for obtaining the frequency-domain results for microwave components. The validity of the TD-FD method in modeling circuit components for MMIC CAD applications is established.

Xiaolei Zhang; Kenneth K. Mei

1988-01-01

153

A multi-dimensional time-marching method of characteristics for viscous and heat-conducting flows  

Microsoft Academic Search

Summary   A numerical scheme is presented which employs the characteristic surfaces in space-time for solving Navier-Stokes equations\\u000a for compressible fluid flow. We consider the general case of a three-dimensional flow, a simplification of which yields the\\u000a equations of the two-dimensional case. Emphasis is put on the method itself. We apply it to simulate a laminar hypersonic\\u000a flow around a circular

J. Ballmann; H. Sanaknaki

2000-01-01

154

A wall-bounded turbulent mixing layer flow over an open step: I. Time-mean and spectral characteristics  

Microsoft Academic Search

The time-mean and spectral characteristics of a wall-bounded turbulent mixing layer flow over an open step were investigated experimentally. Extensive spatio-temporal measurements of the wall pressure fluctuations and velocity fluctuations were performed using a microphone array and an X-type gold-plated hotwire probe, respectively. Air flow was entrained through the open step, forming a wall-bounded turbulent mixing layer flow. Three flow

Ying Zheng Liu; Feng Ke; Han Ping Chen; Hyung Jin Sung

2006-01-01

155

A study of the time and amplitude characteristics of the scintillation counter two meters long with ???-115M photomultiplier tubes  

Microsoft Academic Search

The time and amplitude characteristics of a scintillation counter were investigated on an accelerator beam with a momentum\\u000a of 5 GeV\\/c at the Institute for High Energy Physics. The scintillator, with a length of 2 m and a cross section of 2.5 2.5 cm2, was viewed from its end faces by ???-115M photomultiplier tubes (PMTs). The dependences of the signal

S. P. Denisov; A. Dzierba; A. K. Klimenko; R. Mitchell; V. D. Samoilenko; E. Scott; P. Smith; S. Teige

2006-01-01

156

Detector based on microchannel plates for monitoring space-time characteristics of a circulating beam at Nuclotron  

NASA Astrophysics Data System (ADS)

In the framework of the NICA project preparation and experiments with the extracted Nuclotron beams, the development of an advanced system of circulating-beam diagnostics based on microchannel plates is presented. The detector prototype that has been developed, created, and tested on Nuclotron beams during four runs allows the space-time characteristics of a beam to be measured within a range of singly charged ion intensities from 106 to 109, which is not covered by the existing measuring tools.

Baldin, A. A.; Berlev, A. I.; Kudashkin, I. V.; Fedorov, A. N.

2014-03-01

157

Time-varying characteristics of cross-market linkages with empirical application to Gulf stock markets  

Microsoft Academic Search

Purpose – The purpose of this paper is to propose an empirical procedure for examining the time-varying features of cross-market correlations in selected Gulf stock markets. Design\\/methodology\\/approach – The paper directly infers the cross-market linkages from the stock data using a multivariate dynamic conditional correlation GARCH model (DCC-GARCH). The paper attempts to date the structural breaks in the time-paths of

Mohamed El Hedi Arouri; Duc Khuong Nguyen

2010-01-01

158

An 8 h characteristic time-scale in submillimetre light curves of Sagittarius A*  

NASA Astrophysics Data System (ADS)

We compile and analyse long-term (?10 yr) submillimetre (submm - 1.3, 0.87, 0.43 mm) wavelength light curves of the Galactic Centre black hole, Sagittarius A*. The 0.87 and 0.43 mm data are taken from the literature, while the majority of the 1.3 mm light curve is from previously unpublished SMA and CARMA data. We show that on minute to a few hour time-scales, the variability is consistent with a red noise process with a 230 GHz power-spectrum slope of ? =2.3^{+0.8}_{-0.6} at 95 per cent confidence. The light curve is decorrelated (white noise) on long (month to year) times. We measure a transition time between red and white noise of ? = 8_{-4}^{+3} h at 230 GHz at 95 per cent confidence, with consistent results at 345 and 690 GHz. This corresponds to ?10 orbital times or ?1 inflow (viscous) time at R = 3Rs, a typical radius producing the 230 GHz emission as measured by very long baseline interferometry and found in theoretical accretion flow and jet models. This time-scale is shorter (longer) than those measured by some analyses of radio (near-infrared) light curves. It is roughly consistent with the analogous time-scale inferred in studies of quasar optical light curves after accounting for the difference in emission radius. We find evidence that the submm variability persists at least down to the innermost stable circular orbit, if not the event horizon. These results can be compared quantitatively with similar analyses at different wavebands to test for connections between the variability mechanisms, and with light curves from theoretical models of accreting black holes.

Dexter, Jason; Kelly, Brandon; Bower, Geoffrey C.; Marrone, Daniel P.; Stone, Jordan; Plambeck, Richard

2014-08-01

159

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

SciTech Connect

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)

Konovalov, Aleksandr B; Vlasov, V V [E.I. Zababakhin All-Russian Scientific-Research Institute of Technical Physics, Russian Federal Nuclear Centre, Snezhinsk, Chelyabinsk region (Russian Federation); Kalintsev, A G; Lyubimov, Vladimir V [Research Institute for Laser Physics, St. Petersburg (Russian Federation); Kravtsenyuk, Olga V [Foundation for Research and Technology-Hellas (IESL-FORTH), Institute of Electronic Structure and Lasers, Crete (Greece)

2006-11-30

160

Double loop control strategy with different time steps based on human characteristics.  

PubMed

This paper proposes a cooperative control strategy in consideration of the force sensitivity of human. The strategy consists of two loops: one is the intention estimation loop whose sampling time can be variable in order to investigate the effect of the sampling time; the other is the position control loop with fixed time step. A high sampling rate is not necessary for the intention estimation loop due to the bandwidth of the mechanoreceptors in humans. In addition, the force sensor implemented in the robot is sensitive to the noise induced from the sensor itself and tremor of the human. Multiple experiments were performed with the experimental protocol using various time steps of the intention estimation loop to find the suitable sampling times in physical human robot interaction. The task involves pull-and-push movement with a two-degree-of-freedom robot, and the norm of the interaction force was obtained for each experiment as the measure of the cooperative control performance. PMID:23366291

Gu, Gwang Min; Lee, Jinoh; Kim, Jung

2012-01-01

161

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

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

162

Taekwondo Techniques and Competition Characteristics Involved in Time-Loss Injuries  

PubMed Central

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.

Beis, Konstantinos; Pieter, Willy; Abatzides, George

2007-01-01

163

Seismological evidence on characteristic time of crack healing in the shallow crust  

NASA Astrophysics Data System (ADS)

A continuous observation of shear wave splitting for 17 years reveals a unique temporal variation in seismic anisotropy in the shallow crust induced by a larger earthquake (MW5.7) beneath the Tokai region, Japan. The delay time between the fast and slow wavelets coseismically increased and then decreased back to the pre-event value. The duration of the decreasing stage is about two years. The decrease may indicate crack healing in the upper 10 km of the crust. We approximate the temporal variation in the delay time as a function of logarithm of time, which is concordant with healing phenomena of cracks reported by laboratory experiments. The observation indicates that healing of cracks in crustal rocks is complete in approximately two years.

Hiramatsu, Yoshihiro; Honma, Hiroshi; Saiga, Atsushi; Furumoto, Muneyoshi; Ooida, Tooru

2005-05-01

164

Time and energy characteristics of UV flashes in the atmosphere: Data of the Universitetsky-Tatiana satellite  

NASA Astrophysics Data System (ADS)

Using a detector of near ultra-violet (UV) emission (wavelength range 300-400 nm) [1] onboard the Universitetsky-Tatiana satellite with an orbit height of 950 km and inclination of 81° we have detected and studied short UV flashes [2-5]. In this paper the observed UV flashes are classified according to the type of their time profiles, and the times of emission intensity rise and decay are investigated in every flash. Using the data on time profiles it turned out to be possible to estimate the flash energy in the atmosphere even in case of saturation of a signal measuring channel at the maximum of emission. The energy spectrum of observed flashes is estimated. Time and energy characteristics of the flashes are important for choosing a model of development of electric discharges in the upper atmosphere that are responsible for observed emission.

Garipov, G. K.; Klimov, P. A.; Morozenko, V. S.; Panasyuk, M. I.; Khrenov, B. A.

2011-10-01

165

Influence of Additives and Mixing Time on Crumb Grain Characteristics of Wheat Bread  

Microsoft Academic Search

Cereal Chem. 77(3):370-375 The effect of additives and processing parameters on wheat bread were investigated objectively using image analysis (IA). Five different bread types were produced by varying the ingredients (standard, standard with fat, standard with emulsifiers) and changing the mixing times (90, 150, and 240 sec). A digital IA system for wheat bread was developed from generic commercial software.

P. Crowley; H. Grau; E. K. Arendt

2000-01-01

166

In Vitro Pharmacodynamic Characteristics of Nystatin Including Time-Kill and Postantifungal Effect  

PubMed Central

Four Candida albicans isolates and six non-albicans Candida isolates were evaluated by time-kill methods to characterize the relationship between nystatin concentrations, the rate and extent of fungicidal activity, and the postantifungal effect (PAFE). Against Candida species, nystatin exhibits concentration-dependent fungicidal activity and a pronounced PAFE.

Gunderson, Shana M.; Hoffman, Holly; Ernst, Erika J.; Pfaller, Michael A.; Klepser, Michael E.

2000-01-01

167

In vitro pharmacodynamic characteristics of nystatin including time-kill and postantifungal effect.  

PubMed

Four Candida albicans isolates and six non-albicans Candida isolates were evaluated by time-kill methods to characterize the relationship between nystatin concentrations, the rate and extent of fungicidal activity, and the postantifungal effect (PAFE). Against Candida species, nystatin exhibits concentration-dependent fungicidal activity and a pronounced PAFE. PMID:10991881

Gunderson, S M; Hoffman, H; Ernst, E J; Pfaller, M A; Klepser, M E

2000-10-01

168

Characteristics and fates of soluble microbial products in ceramic membrane bioreactor at various sludge retention times  

Microsoft Academic Search

The formation and fate of soluble microbial products (SMP) in membrane bioreactor (MBR) was investigated at various sludge retention times (SRT) for 170 days. The SMP concentration was estimated by feeding glucose, which could be completely degraded, and by measuring the dissolved organic carbon (DOC) of the effluent from MBR. Under the conditions of SRT of 20 days, influent DOC

Hang-Sik Shin; Seok-Tae Kang

2003-01-01

169

Multiscaling for systems with a broad continuum of characteristic lengths and times: Structural transitions in nanocomposites.  

PubMed

The multiscale approach to N-body systems is generalized to address the broad continuum of long time and length scales associated with collective behaviors. A technique is developed based on the concept of an uncountable set of time variables and of order parameters (OPs) specifying major features of the system. We adopt this perspective as a natural extension of the commonly used discrete set of time scales and OPs which is practical when only a few, widely separated scales exist. The existence of a gap in the spectrum of time scales for such a system (under quasiequilibrium conditions) is used to introduce a continuous scaling and perform a multiscale analysis of the Liouville equation. A functional-differential Smoluchowski equation is derived for the stochastic dynamics of the continuum of Fourier component OPs. A continuum of spatially nonlocal Langevin equations for the OPs is also derived. The theory is demonstrated via the analysis of structural transitions in a composite material, as occurs for viral capsids and molecular circuits. PMID:20661319

Pankavich, S; Ortoleva, P

2010-06-01

170

Multiscaling for systems with a broad continuum of characteristic lengths and times: Structural transitions in nanocomposites  

PubMed Central

The multiscale approach to N-body systems is generalized to address the broad continuum of long time and length scales associated with collective behaviors. A technique is developed based on the concept of an uncountable set of time variables and of order parameters (OPs) specifying major features of the system. We adopt this perspective as a natural extension of the commonly used discrete set of time scales and OPs which is practical when only a few, widely separated scales exist. The existence of a gap in the spectrum of time scales for such a system (under quasiequilibrium conditions) is used to introduce a continuous scaling and perform a multiscale analysis of the Liouville equation. A functional-differential Smoluchowski equation is derived for the stochastic dynamics of the continuum of Fourier component OPs. A continuum of spatially nonlocal Langevin equations for the OPs is also derived. The theory is demonstrated via the analysis of structural transitions in a composite material, as occurs for viral capsids and molecular circuits.

Pankavich, S.; Ortoleva, P.

2010-01-01

171

Global dynamical modeling of time series and application to restoration of broadband signal characteristics  

SciTech Connect

We show the principle possibility of the external complex action restoring using the nonlinear dynamics inverse problem solution. It is shown that broadband signal can be restored from the time series of the process generated by nonstationary chaotic system using the reconstructed model as the nonlinear filter. {copyright} {ital 1996 American Institute of Physics.}

Gribkov, D.A.; Gribkova, V.V.; Kuznetsov, Y.I.; Rzhanov, A.G. [Physical Department of Moscow State University, Moscow, 119899 (Russia)

1996-06-01

172

BLAST Training: Estimating Channel Characteristics for High Capacity Space-Time Wireless  

Microsoft Academic Search

BLAST (Bell Labs Layered Space-Time) is a multiple-antenna communicationscheme whose outage capacity in a Rayleigh flat fading environment grows linearlywith the minimum of the number of transmit and receive antennas, with no increasein bandwidth or transmitted power. Based on its knowledge of the matrix ofpropagation coefficients, the receiver performs two critical operations: nulling andcancellation, that in effect create independent virtual

Thomas L. Marzetta

1999-01-01

173

Time Sensitivity Factor of Single Pulmonary Nodule: A New Cancer Characteristic Metabolic Parameter by 18F-FDG PET  

PubMed Central

Objective. To calculate the time sensitivity factor (S) for discriminating the solitary pulmonary nodule (SPN) by FDG PET at different time points. Methods. The multiple time-point FDG PET images from 41 patients for evaluating SPN seen on chest X-ray or CT were prospectively analyzed to calculate and evaluate S against the gold standard of tissue histology (n = 38) or long term clinicoradiographic follow-up (n = 3). The maximal standardized uptake values (SUV) at the 3 hourly time points were measured. The S was calculated using S = d{ln?(SUV)}/d{ln?(t)} at 3 different time intervals. ROC analysis of the S parameters was performed to evaluate the optimal cut-off value and their accuracy in classifying the SPN. Results. The SUV in malignant SPN was higher than the corresponding value in benign lesions at all 3 hourly time points (P < 0.003). The S parameters using 3 different time intervals all significantly separated the two groups (P < 0.0005) with an optimal cut-off point near the theoretical value of zero with a high sensitivity of 100% and specificity of 86%. Conclusion. The S can be calculated for SPNs using multiple time-point FDG PET, providing a tumor characteristic metabolic parameter with high discrimination power using a simple positive value representing malignancy.

Cheng, Ching-Yuan; Lee, Kwo-Whei; Lee, Chiang-Hsuan; Tyan, Yeu-Sheng; Cheng, Cheng-Yi; Wang, Jhi-Joung; Yang, Chao-Wei; Huang, Wen-Sheng; Oliver Wong, Ching-Yee

2014-01-01

174

Distinguishing 6 Population Subgroups by Timing and Characteristics of the Menopausal Transition  

PubMed Central

Changes in women’s menstrual bleeding patterns precede the onset of menopause. In this paper, the authors identify population subgroups based on menstrual characteristics of the menopausal transition experience. Using the TREMIN data set (1943–1979), the authors apply a Bayesian change-point model with 8 parameters for each woman that summarize change in menstrual bleeding patterns during the menopausal transition. The authors then use estimates from this model to classify menstrual patterns into subgroups using a K-medoids algorithm. They identify 6 subgroups of women whose transition experience can be distinguished by age at onset, variability of the menstrual cycle, and duration of the early transition. These results suggest that for most women, mean and variance change points are well aligned with proposed bleeding markers of the menopausal transition, but for some women they are not clearly associated. Increasing understanding of population differences in the transition experience may lead to new insights into ovarian aging. Because of age inclusion criteria, most longitudinal studies of the menopausal transition probably include only a subset of the 6 subgroups of women identified in this paper, suggesting a potential bias in the understanding of both the menopausal transition and the linkage between the transition and chronic disease.

Huang, Xiaobi; Harlow, Sioban D.; Elliott, Michael R.

2012-01-01

175

Performance Characteristics of a Methodology to Quantify Adverse Events over Time in Hospitalized Patients  

PubMed Central

Objective To assess the performance characteristics of the Institute for Healthcare Improvement Global Trigger Tool (GTT) to determine its reliability for tracking local and national adverse event rates. Data Sources Primary data from 2008 chart reviews. Study Design A retrospective study in a stratified random sample of 10 North Carolina hospitals. Hospital-based (internal) and contract research organization–hired (external) reviewers used the GTT to identify adverse events in the same 10 randomly selected medical records per hospital in each quarter from January 2002 through December 2007. Data Collection/Extraction Interrater and intrarater reliability was assessed using ? statistics on 10 percent and 5 percent, respectively, of selected medical records. Additionally, experienced GTT users reviewed 10 percent of records to calculate internal and external teams' sensitivity and specificity. Principal Findings Eighty-eight to 98 percent of the targeted 2,400 medical records were reviewed. The reliability of the GTT to detect the presence, number, and severity of adverse events varied from ?=0.40 to 0.60. When compared with a team of experienced reviewers, the internal teams' sensitivity (49 percent) and specificity (94 percent) exceeded the external teams' (34 and 93 percent), as did their performance on all other metrics. Conclusions The high specificity, moderate sensitivity, and favorable interrater and intrarater reliability of the GTT make it appropriate for tracking local and national adverse event rates. The strong performance of hospital-based reviewers supports their use in future studies.

Sharek, Paul J; Parry, Gareth; Goldmann, Donald; Bones, Kate; Hackbarth, Andrew; Resar, Roger; Griffin, Frances A; Rhoda, Dale; Murphy, Cathy; Landrigan, Christopher P

2011-01-01

176

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

PubMed

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

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

2012-06-01

177

Image streak techniques: ISKRA-5 facility X-ray space-time and spectral characteristics recording  

SciTech Connect

Presented below are the X-ray image streak techniques used to study the spectral- and spectral-spatial time behavior of the ISKRA-5 facility laser-irradiated target X-ray radiation. For this purpose, we developed several 0.1-10 keV range X-ray slit streak cameras with 3x10{sup {minus}11}-s time resolution. Our X-ray imaging layout made it possible to simultaneously project several target images (in different spectral intervals) to the photocathode and streak them synchroniously. These techniques made it possible to: Study the microsphere target and plasma corona implosion dynamics; investigate the well-adjacent plasma electron temperature behavior; determine the compressed core lifetime; and monitor the state of the external (non-irradiated) target surface. 7 refs., 4 figs.

Lazarchuk, V.P.; Murugov, V.M.; Petrov, S.I.; Senik, A.V. [VNIIEF Russian Federal Nuclear Center, Novgorod (Russian Federation)

1994-12-31

178

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

NASA Technical Reports Server (NTRS)

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.

Wilson, D. J.

1974-01-01

179

The effects of timing of feedback and learner characteristics on the end-of-training performance  

Microsoft Academic Search

Training new employees is time consuming and costly. When training does not produce knowledge retention, changes in attitude, and changes in on-the-job performance, much of the investment is wasted, and training administrators question the justification of high-cost training. When there has been no skill transfer, the trainer and the employee as well as the organization is at a loss. In

Rodello Apigo Borillo

1996-01-01

180

The Real Time Diagnostics of Combustion Characteristics of Solid Propellant by Remote Sensing FTIR System  

Microsoft Academic Search

The flame infrared emission spectra between 4700 and 800 cm of nitroguanidine solid propellant combustion were recorded using a real time, remote sensing Fourier transform infrared (FTIR) spectrometer with a spectral resolution of 2 cm. The combustion flame temperature of this high intensity IR propellant combustion was studied via the fine structure of the rotational vibrational emission bands of HF (4400?3950 cm) and

Yan Li; Junde Wang

2003-01-01

181

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

PubMed

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

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

182

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

NASA Astrophysics Data System (ADS)

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.

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

183

Physicochemical and toxicological characteristics of welding fume derived particles generated from real time welding processes.  

PubMed

Welding fume particles have been well studied in the past; however, most studies have examined welding fumes generated from machine models rather than actual exposures. Furthermore, the link between physicochemical and toxicological properties of welding fume particles has not been well understood. This study aims to investigate the physicochemical properties of particles derived during real time welding processes generated during actual welding processes and to assess the particle size specific toxicological properties. A compact cascade impactor (Harvard CCI) was stationed within the welding booth to sample particles by size. Size fractionated particles were extracted and used for both off-line physicochemical analysis and in vitro cellular toxicological characterization. Each size fraction was analyzed for ions, elemental compositions, and mass concentration. Furthermore, real time optical particle monitors (DustTrak™, TSI Inc., Shoreview, Minn.) were used in the same welding booth to collect real time PM2.5 particle number concentration data. The sampled particles were extracted from the polyurethane foam (PUF) impaction substrates using a previously developed and validated protocol, and used in a cellular assay to assess oxidative stress. By mass, welding aerosols were found to be in coarse (PM 2.5–10), and fine (PM 0.1–2.5) size ranges. Most of the water soluble (WS) metals presented higher concentrations in the coarse size range with some exceptions such as sodium, which presented elevated concentration in the PM 0.1 size range. In vitro data showed size specific dependency, with the fine and ultrafine size ranges having the highest reactive oxygen species (ROS) activity. Additionally, this study suggests a possible correlation between welders' experience, the welding procedure and equipment used and particles generated from welding fumes. Mass concentrations and total metal and water soluble metal concentrations of welding fume particles may be greatly influenced by these factors. Furthermore, the results also confirmed the hypothesis that smaller particles generate more ROS activity and should be evaluated carefully for risk assessment. PMID:24592438

Chang, Cali; Demokritou, Philip; Shafer, Martin; Christiani, David

2013-01-01

184

Timing of Malaria Infection during Pregnancy Has Characteristic Maternal, Infant and Placental Outcomes  

PubMed Central

We conducted a clinical study of pregnant women in Blantyre, Malawi to determine the effect of the timing of malaria infection during pregnancy on maternal, infant and placental outcomes. Women were enrolled in their first or second trimester of their first or second pregnancy and followed every four weeks until delivery. Three doses of sulfadoxine-pyrimethamine were given for intermittent preventive treatment for malaria, and all episodes of parasitemia were treated according to the national guidelines. Placentas were collected at delivery and examined for malaria parasites and pigment by histology. Pregnant women had 0.6 episodes of malaria per person year of follow up. Almost all episodes of malaria were detected at enrollment and malaria infection during the follow up period was rare. Malaria and anemia at the first antenatal visit were independently associated with an increased risk of placental malaria detected at delivery. When all episodes of malaria were treated with effective antimalarial medication, only peripheral malaria infection at the time of delivery was associated with adverse maternal and infant outcomes. One quarter of the analyzed placentas had evidence of malaria infection. Placental histology was 78% sensitive and 89% specific for peripheral malaria infection during pregnancy. This study suggests that in this setting of high antifolate drug resistance, three doses of sulfadoxine-pyrimethamine maintain some efficacy in suppressing microscopically detectable parasitemia, although placental infection remains frequent. Even in this urban setting, a large proportion of women have malaria infection at the time of their first antenatal care visit. Interventions to control malaria early and aggressive case detection are required to limit the detrimental effects of pregnancy-associated malaria.

Kalilani-Phiri, Linda; Thesing, Phillip C.; Nyirenda, Osward M.; Mawindo, Patricia; Madanitsa, Mwayi; Membe, Gladys; Wylie, Blair; Masonbrink, Abbey; Makwakwa, Kingsley; Kamiza, Steve; Muehlenbachs, Atis; Taylor, Terrie E.; Laufer, Miriam K.

2013-01-01

185

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

NASA Astrophysics Data System (ADS)

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.

Giorgio, Massimiliano; Greco, Roberto

2010-05-01

186

Performance Characteristics of a New Hybrid Triple Quadrupole Time-of-Flight Tandem Mass Spectrometer  

PubMed Central

The TripleTOF 5600 System, a hybrid triple quadrupole time-of-flight mass spectrometer, was evaluated to explore the key figures of merit in generating peptide and protein identifications which included spectral acquisition rates, data quality, proteome coverage, and biological depth. Employing a Saccharomyces cerevisiae tryptic digest, careful consideration of several performance features demonstrated that the speed of the TripleTOF contributed most to the resultant data. The TripleTOF system was operated with 8, 20, and 50 MS/MS events in an effort to compare to other MS technologies and to demonstrate the abilities of the instrument platform.

Andrews, Genna L.; Simons, Brigitte L.; Young, J. Bryce; Hawkridge, Adam M.; Muddiman, David C.

2011-01-01

187

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

NASA Technical Reports Server (NTRS)

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.

Wilson, D. J.

1975-01-01

188

Local characteristics of time and latitude observations made at the IPMS collaborating stations  

NASA Astrophysics Data System (ADS)

The residuals of the optical observations of time and latitude obtained at the IPMS collaborating stations for the period from 1967 to 1987, have been derived in this study by removing the effect of the earth's rotation and after elimination of artificial variations due to replacement and overhaul of the instruments and changes in the star observation system. To be free of seasonal variations, account is taken of the difference in the pole positions derived from the IRIS program and the IPMS of about 0.002 arcsec and 0.007 arcsec for x and y respectively, and of differences in UT1 - TAI of about -0.02 arcsec. Long-term variations of the residuals by a 6-year running mean are displayed; they show systematic variations at the Asian and the European stations.

Ishii, H.; Goto, Y.; Ishikawa, T.

1990-12-01

189

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

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

190

Effect of swirling flow by normal injection of secondary air on the gas residence time and mixing characteristics in a lab-scale cold model combustor  

Microsoft Academic Search

The present study investigates gas residence time and mixing characteristics for various swirl numbers generated by injection\\u000a of secondary air into a lab-scale cylindrical combustor. Fine dust particles and butane gas were injected into the test chamber\\u000a to study the gas residence time and mixing characteristics, respectively. The mixing characteristics were evaluated by standard\\u000a deviation value of trace gas concentration

D. Shin; B. Jeon; T. Yu; J. Hwang

2006-01-01

191

Electrical characteristics and carrier transport mechanisms of write-once-read-many-times memory elements based on graphene oxide diodes  

NASA Astrophysics Data System (ADS)

We demonstrated write-once-read-many-times (WORM) memory devices based on graphene oxide (GO) film sandwiched between ITO and LiF/Al electrode. The devices showed irreversible electrical transition from the low conductivity (OFF) state to the high conductivity (ON) state and the ON/OFF current ratio between the conductivities of two states was over 5.7 × 104. The results of I-V data, AFM and SEM images indicated that the WORM memory characteristics of GO diodes were mainly attributed to charge trapping at GO layers and interfacial properties between GO and LiF/Al electrode.

Yi, Mingdong; Zhao, Litao; Fan, Quli; Xia, Xianhai; Ai, Wei; Xie, Linghai; Liu, Xiangmei; Shi, Naien; Wang, Wenjun; Wang, Yanping; Huang, Wei

2011-09-01

192

Space-time characteristics of earthquake sources in various tectonic environments  

NASA Astrophysics Data System (ADS)

Earthquake hazards are difficult to accurately evaluate along slow plate boundaries and in plate interiors because the locations of recorded earthquakes appear to have a higher probability of earthquakes than locations where none have been recorded. In these regions, a non-uniform earthquake hazard is often assumed. Assuming that the hazard is uniform, earthquake simulations created synthetic earthquake records with an average time between earthquakes. The results showed that non-uniform hazard cannot be assumed when the earthquake record is short. Giant earthquakes (Mw>8.5) extend earthquake destruction from a regional hazard to a global hazard by creating a tsunami. Giant earthquakes occur at subduction zones but have not been recorded along all subduction zones. Ruff and Kanamori (1980) showed the subduction zone convergence rate and lithosphere age need to be fast and young, respectively, to create giant earthquakes. To examine the relationship using recent data, the thermal parameter (?), defined as the produce of the convergence rate and the lithospheric age, was compared with the largest earthquake magnitude recorded along each subduction zone. There was no correlation between the thermal parameter and the magnitude. Hence, the convergence rate and lithospheric age do not predict which subduction zones can create giant earthquakes. While giant earthquakes are thrust earthquakes, comparing earthquakes with different focal mechanisms can increase understanding of earthquakes themselves. To examine how earthquake stress drops varies with focal mechanism and tectonic environment, a relative stress drop was calculated for earthquakes from the observed seismic moment and the source time function duration. Earthquakes with different focal mechanisms and tectonic environments did not show significant differences in stress drop. It is not known why these results did not duplicate previously published results, which showed different stress drops for different focal mechanisms (Stein and Pelayo, 1991). Focal mechanisms also yield stress directions but may not be precisely calculated. The resolution of focal mechanisms was tested in Java to study subsurface fracture orientations and stress directions. The P-wave polarities at each station were used to calculate the precision of focal mechanisms. Strike and dip of focal mechanisms were reliably identified from these data, but slip directions were not precisely calculated.

Swafford, Laura C.

193

Effect of storage time and temperature on the physicochemical and sensory characteristics of commercial apricot jam.  

PubMed

Storage conditions are important factors for jam quality. The objective of this study was to monitor the physicochemical stability and sensorial profile of apricot jam during storage for 60 days at 5 °C, 25 °C and 37 °C. For that purpose, special attention was paid to total soluble solids (TSS), titratable acidity (TA), colour, free amino acids (FAA), total sugars (TS) and hydroxymethylfurfural (HMF). The decreasing parameter for jam at the end of storage under 5 °C, 25 °C and 37 °C, respectively, were 16.81%, 34.30% and 56.01% for FAA, and 5.52%, 9.02% and 7.46% for TS; likewise, the increasing were 19.81%, 22.94% and 25.07% for TA, 3.15%, 4.08% and 4.47% for TSS, 15.96%, 112.76% and 150% for HMF. Jam stability was better at 5 °C than 25 °C and 37 °C. The interaction time-temperature factor had significant effects on pH, TS, FAA and HMF, unlike TA, TSS and sensorial profile. PMID:24128444

Touati, Noureddine; Tarazona-Díaz, Martha Patricia; Aguayo, Encarna; Louaileche, Hayette

2014-02-15

194

Clinical time-course and characteristics of islet cell cytoplasmatic antibodies in childhood diabetes.  

PubMed

Circulating islet cell antibodies (ICA) were present in high frequency (80%) early after diagnosis and decreased in the time course of childhood diabetes mellitus. The complement fixing ability of islet cell antibodies (CF-ICA) in the course of the disease appeared to depend on the titre of ICA: the coefficient of correlation between ICA and CF-ICA titres was 0.79 and all ICA's with a titre over 16 were complement-fixing. Incubating fresh frozen human pancreatic sections thrice rather than once with the children's sera, increased the detectability of complement fixation by a factor 1.4 in all ICA-positive sera. Thus tested, the detection of complement fixation per se did not appear to have a separate pathogenic significance, as the fraction of complement fixing ICA's was almost constant throughout the clinical course. The presence of ICA-IgG subclasses also was dependent on the ICA titre: above a titre of 16 mostly all four subclasses could be detected. Incubating the pancreatic tissue thrice rather than once with ICA-positive sera resulted in enhanced detectability of ICA-IgG1. Early in the course of childhood diabetes, including two prediabetic children, most of the IgG subclasses could be detected in ICA, but after a duration of one year IgG1 alone was mainly seen. In two other children, having a family history of insulin-dependency, restriction to the IgG2 subclass was found. PMID:6368297

Bruining, G J; Molenaar, J; Tuk, C W; Lindeman, J; Bruining, H A; Marner, B

1984-01-01

195

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

196

Characteristics of First-Time Alcohol Treatment Seekers: The COMBINE Study*  

PubMed Central

Objective: The current study compared alcoholics who entered treatment for the first time with those who had reported one or more prior treatment experiences using a large sample (N = 1,362) of alcoholics who entered the National Institute on Alcohol Abuse and Alcoholism-sponsored COMBINE (Combining Medications and Behavioral Interventions) Study of pharmacological and behavioral treatment efficacy. Method: Participants were categorized into three prior-treatment groups: (1) treatment naive (n = 691, 50.73%), (2) one to two prior treatments (n = 380, 27.90%), or (3) three or more prior treatments (n = 291, 21.37%). Groups were compared at baseline on multiple drinking and psychosocial variables. Results: The treatment-naive group was more likely to be female, educated, married, and employed. They reported the lowest levels of drinks per drinking day, average drinks per day, alcohol dependence, craving, and alcohol-related consequences; but, they had the oldest age at onset of alcohol problems. Both the treatment-naive group and the one-to-two prior-treatment group had lower percentage days abstinent within the prior 30 days, compared with the three-or-more group (22% and 25% vs 32%, respectively). The treatment-naive group reported the least commitment to an abstinence goal (43% vs 70% and 80%, respectively) and the lowest mean number of Alcoholics Anonymous meetings attended (0.86 vs 3.10 vs 6.91, respectively). They also reported fewer psychological symptoms, less distress, and higher levels of quality of life on physical, emotional, and environmental domains, as well as social relationships. Conclusions: Results suggest that a greater understanding of treatment-naive versus treatment-experienced clients may provide a better profile of help-seeking behavior and may suggest different approaches to treatment.

LoCastro, Joseph S.; Potter, Jennifer Sharpe; Donovan, Dennis M.; Couper, David; Pope, Kimberly W.

2008-01-01

197

Statistical characteristics of hydrogen and oxygen ENA emission from the storm-time ring current  

NASA Astrophysics Data System (ADS)

The present study statistically examines energetic neutral atom (ENA) emission from the storm-time inner magnetosphere using measurements from the IMAGE/HENA instrument. It is found that the total image-integrated ENA energy flux is well correlated (?c.c.? ˜ 0.7) with the Sym-H index. However, the increase is not linear but exponential with ?Sym-H?, which can be attributed to the fact that the ring current moves closer to Earth as the storm becomes more intense. The oxygen (52-180 keV) energy flux increases more steeply with ?Sym-H? than the hydrogen (27-60 keV and 60-119 keV) energy flux, which is consistent with the results of in situ measurements reported previously. The relative contribution of near-Earth emission to total energy flux is larger during the main phase than during the recovery phase presumably because during the main phase the ring current moves closer to Earth and ion precipitation is more intense. Interestingly, if Sym-H is the same, the ring current emission of 60-119 keV hydrogen and 52-180 keV oxygen is systematically weaker during the main phase than during the recovery phase. This can be explained if the ring current is indeed weaker during the main phase than during the recovery phase (for a given Sym-H), and its smaller contribution to Sym-H is compensated by the contribution of a more intense tail current. This idea is confirmed by the finding that the geosynchronous magnetic field is more stretched during the main phase.

Ohtani, S.; Brandt, P. C.; Singer, H. J.; Mitchell, D. G.; Roelof, E. C.

2006-06-01

198

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

PubMed Central

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.

Brambillasca, Sebastian; Purtscher, Frederick; Britos, Alejandro; Repetto, Jose L.; Cajarville, Cecilia

2010-01-01

199

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

USGS Publications Warehouse

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.

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

2007-01-01

200

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

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.

2014-01-01

201

Time-frequency heart rate variability characteristics of young adults during physical, mental and combined stress in laboratory environment.  

PubMed

The goal of this study was to evaluate the changes in heart rate variability (HRV) parameters due to a specific physical, mental or combined load. More specifically, the difference in effect between mental load and physical activity is studied. In addition, the effect of the combined physical and mental demand on the HRV parameters was examined and compared with the changes during the single task. In a laboratory environment, 28 subjects went through a protocol with different types of load (physical and/or mental), each followed by a period of rest. Continuous wavelet transformation was applied to create time series of instantaneous power and frequency in specified frequency bands (LF and HF). HF could distinguish the active conditions from the rest condition, meaning that HRV is sensitive to any change in mental or physical state. Differences in HRV parameters were observed between physical, mental and the combined load. In conclusion, we were able to distinguish between rest, physical and mental condition by combining different HRV characteristics. The addition of a mental load to a physical task had an extra effect on the HRV characteristics. PMID:22254720

Taelman, Joachim; Vandeput, Steven; Gligorijevi?, Ivan; Spaepen, Arthur; Van Huffel, Sabine

2011-01-01

202

DNAPL Mobility in Heterogeneous Porous Media: Sensitivity of Migration Times to Source Characteristics and Release Location Parameters  

NASA Astrophysics Data System (ADS)

This study examined the factors the influence the time required for a release of dense nonaqueous phase liquid (DNAPL) to cease migrating through heterogeneous porous media below the watertable. Using numerical simulation, the temporal and spatial sensitivity of DNAPL migration was evaluated for four DNAPL source characteristics - nonwetting fluid type (i.e., density and viscosity), interfacial tension (IFT), source strength, and volume released - and for three release location parameters - mean permeability, porosity, and hydraulic gradient. The study was conducted using the multiphase code DNAPL3D whose constitutive relationships were developed, and validated, for DNAPL migration in both space and time. All numerical simulations employed a single correlated random permeability field and identical boundary and source conditions to the base case, except for systematic variation of the parameter under investigation. It was found that all of the parameters examined had a significant spatial effect on the final DNAPL migration pattern, either on the overall volume of subsurface invaded (e.g., direct correlation to volume released) or on the amount of lateral spreading (e.g., direct correlation to IFT). However, only two of the parameters were found to have a significant effect on the time required to achieve the final, stable distribution of DNAPL pools and residual. Migration rates were very sensitive to DNAPL type, with predicted cessation times ranging from 30 days for the high mobility fluid tetrachloroethylene (PCE) to over 1000 years for the low mobility fluid coal tar. These simulations reveal that while density primarily influences the spatial extent of penetration and viscosity primarily influences penetration rate, the two effects are not independent due to interactions with site-specific heterogeneity. In addition, the mean permeability of the heterogeneous domain was found to be significant, with increases in mean k corresponding to decreases in both cessation time and degree of lateral spreading.

Pang, T.; Gerhard, J. I.; Kueper, B. H.

2004-12-01

203

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

PubMed

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

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

2014-06-01

204

The Eect of Exposure Time to Clean Room Air on Characteristic Parameters of Au /Epilayer n-Si Schottky Diodes  

NASA Astrophysics Data System (ADS)

A study has been made on determination and comparison of current-voltage (I-V) and capacitance-voltage (C-V) characteristics parameters of Au/n-Si Schottky barrier diodes (SBDs) with and without thin native oxide layer fabricated on n-type Si grown by LPE (Liquid-phase Epitaxy) technique. The native oxide layer with different thicknesses on chemically cleaned on Si surface were obtained by exposing the surfaces to clean room air before evaporating metal. The native oxide thicknesses of samples D2, D3, D4 and D5 are in the form D2 < D3 < D4 ? D5, depending on the exposing time. It has been seen that the values of barrier height Fb of samples D2(0.64 eV), D3(0.66 eV), D4(0.69 eV) and D5(0.69 eV) with the interfacial layer increased with increasing the exposure time and tended to that of the initial sample D1 (nonoxidezed sample, 0.74 eV), and thus also their I-V and C-V curves. The reverse current of sample D1 showed slight nonsaturating behavior. This ''soft'' behavior has been ascribed to the spatial inhomogeneity in the barrier heights at the MS interface. In particular, reverse bias curves of samples D2, D3, D4 and D5 have shown excellent saturation which may be attributed to the passivation of the semiconductor surface states by the native oxide layer which reduces the penetration of the wave functions of electron in the metal into the semiconductor. Especially, the I-V characteristics and experimental parameters of our devices are in agreement with recently reported results revealed by the pulsed surface photovoltage technique for the electronic properties of the HF-treated Si surface during initial oxidation in air.

Saðlam, M.; Nuhoðlu, Ç.; Ayyildiz, E.; Türüt, A.; Çetýnkara, H. A.

1998-05-01

205

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

USGS Publications Warehouse

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.

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

206

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

SciTech Connect

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.

Liu Shengzhi; Zhang Naiyao; Cui Zhenhua [Tsinghua University (China)

2004-11-15

207

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

PubMed

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. PMID:20210447

Chao, Guo-Shan; Sung, Kung-Bin

2010-01-01

208

Changes in characteristics of soluble microbial products in membrane bioreactors associated with different solid retention times: Relation to membrane fouling.  

PubMed

A membrane bioreactor (MBR) is a promising wastewater treatment technology, but there is a need for efficient control of membrane fouling, which increases operational and maintenance costs. Soluble microbial products (SMP) have been reported to act as major foulants in the operation of MBRs used for wastewater treatment. In this study, SMP in MBRs operated with different sludge retention times (SRTs) were investigated by means of various analytical techniques and their relations to the evolution of membrane fouling were considered. Bench-scale filtration experiments were carried out in a laboratory with synthetic wastewater to eliminate fluctuations that would occur with the use of real wastewater and that would lead to fluctuations in compositions of SMP. Three identical submerged MBRs were operated for about 50 days under the same conditions except for SRT (17, 51 and 102 days). Accumulation of SMP in the MBRs estimated by conventional analytical methods (i.e., the phenol-sulfuric acid method and the Lowry method) was significant in the cases of short SRTs. However, the degrees of membrane fouling in the MBRs were not directly related to the concentrations of SMP in the reactors estimated by the conventional analytical methods. Non-conventional analytical methods such as excitation-emission matrix (EEM) fluorescence spectroscopy revealed that characteristics of SMP in the three reactors considerably differed depending on SRT. Foulants were extracted from the fouled membranes at the end of the operation and were compared with SMP in each MBR. It was clearly shown that characteristics of the foulants were different depending on SRT, and similarities between SMP and the extracted foulants were recognized in each MBR on the basis of results of EEM measurements. However, such similarities were not found on the basis of results obtained by using the conventional methods for analysis of SMP. The results of this study suggest that the use of conventional methods for analysis of SMP is not appropriate for investigation of membrane fouling in MBRs. PMID:19059627

Kimura, Katsuki; Naruse, Takuro; Watanabe, Yoshimasa

2009-03-01

209

Time  

ERIC Educational Resources Information Center

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."…

Circle, David

2005-01-01

210

Performance Characteristics and Comparison of Abbott and artus Real-Time Systems for Hepatitis B Virus DNA Quantification ?  

PubMed Central

Virological monitoring of hepatitis B virus (HBV) DNA is critical to the management of HBV infection. With several HBV DNA quantification assays available, it is important to use the most efficient testing system for virological monitoring. In this study, we evaluated the performance characteristics and comparability of three HBV DNA quantification systems: Abbott HBV real-time PCR (Abbott PCR), artus HBV real-time PCR with QIAamp DNA blood kit purification (artus-DB), and artus HBV real-time PCR with the QIAamp DSP virus kit purification (artus-DSP). The lower limits of detection of these systems were established against the WHO international standards for HBV DNA and were found to be 1.43, 82, and 9 IU/ml, respectively. The intra-assay and interassay coefficients of variation of plasma samples (1 to 6 log10 IU/ml) ranged between 0.05 to 8.34% and 0.16 to 3.48% for the Abbott PCR, 1.53 to 26.85% and 0.50 to 12.89% for artus-DB, and 0.29 to 7.42% and 0.94 to 3.01% for artus-DSP, respectively. Ninety HBV clinical samples were used for comparison of assays, and paired quantitative results showed strong correlation by linear regression analysis (artus-DB with Abbott PCR, r = 0.95; Abbott PCR with artus-DSP, r = 0.97; and artus-DSP with artus-DB, r = 0.94). Bland-Altman analysis showed a good level of agreement for Abbott PCR and artus-DSP, with a mean difference of 0.10 log10 IU/ml and limits of agreement of ?0.91 to 1.11 log10 IU/ml. No genotype-specific bias was seen in all three systems for HBV genotypes A, C, and D, which are predominant in this region. This finding illustrates that the Abbott real-time HBV and artus-DSP systems show more comparable performance than the artus-DB system, meeting the current guidelines for assays to be used in the management of hepatitis B.

Ismail, Ashrafali M.; Sivakumar, Jayashree; Anantharam, Raghavendran; Dayalan, Sujitha; Samuel, Prasanna; Fletcher, Gnanadurai J.; Gnanamony, Manu; Abraham, Priya

2011-01-01

211

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

212

Time-frequency characteristics and dynamics of sleep spindles in WAG/Rij rats with absence epilepsy.  

PubMed

In rat models of absence epilepsy, epileptic spike-wave discharges appeared in EEG spontaneously, and the incidence of epileptic activity increases with age. Spike-wave discharges and sleep spindles are known to share common thalamo-cortical mechanism, suggesting that absence seizures might affect some intrinsic properties of sleep spindles. This paper examines time-frequency EEG characteristics of anterior sleep spindles in non-epileptic Wistar and epileptic WAG/Rij rats at the age of 7 and 9 months. Considering non-stationary features of sleep spindles, EEG analysis was performed using Morlet-based continuous wavelet transform. It was found, first, that the average frequency of sleep spindles in non-epileptic Wistar rats was higher than in WAG/Rij (13.2 vs 11.2 Hz). Second, the instantaneous frequency ascended during a spindle event in Wistar rats, but it was constant in WAG/Rij. Third, in WAG/Rij rats, the number and duration of epileptic discharges increased in a period between 7 and 9 months of age, but duration and mean value of intra-spindle frequency did not change. In general, age-dependent aggravation of absence seizures in WAG/Rij rats did not affect EEG properties of sleep spindles; it was suggested that pro-epileptic changes in thalamo-cortical network in WAG/Rij rats might prevent dynamic changes of sleep spindles that were detected in Wistar. PMID:24231550

Sitnikova, Evgenia; Hramov, Alexander E; Grubov, Vadim; Koronovsky, Alexey A

2014-01-16

213

Comparing single vehicle and multivehicle fatal road crashes: a joint analysis of road conditions, time variables and driver characteristics.  

PubMed

The difference between single vehicle crashes and multivehicle crashes was investigated in a collection of fatal crashes from six European countries. Variables with respect to road conditions, time variables, and participant characteristics were studied separately at first and then jointly in a logistic multiple regression model allowing to weigh different accounts of single vehicle as opposed to multivehicle crash occurrence. The most important variables to differentiate between single and multivehicle crashes were traffic flow, the presence of a junction and the presence of a physical division between carriageways. Heavy good vehicles and motorcycles were less likely to be involved in single vehicle crashes than cars. Moreover crashes of impaired drivers with more passengers were more likely to be single vehicle crashes than those of other drivers. Young drivers, rural roads, nights and weekends were all shown to have a higher proportion of single vehicle crashes but in the multivariate analysis these effects were demonstrated to be mediated by the road conditions named above. PMID:23622842

Martensen, Heike; Dupont, Emmanuelle

2013-11-01

214

Time 2 tlk 2nite: Use of Electronic Media by Adolescents during Family Meals and Associations with Demographic Characteristics, Family Characteristics, and Foods Served.  

PubMed

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

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

2014-07-01

215

The Characteristic of Heat Wave Effects on Coronary Heart Disease Mortality in Beijing, China: A Time Series Study  

PubMed Central

Background There is limited evidence for the impacts of heat waves on coronary heart disease (CHD) mortality in Beijing, capital city of China. Objectives We aimed to find a best heat wave definition for CHD mortality; and explore the characteristic of heat wave effects on CHD in Beijing, China. Methods We obtained daily data on weather and CHD mortality in Beijing for years 2000–2011. A quasi-Poisson regression model was used to assess the short-term impact of heat waves on CHD mortality in hot season (May–September), while controlling for relative humidity, day of the week, long-term trend and season. We compared 18 heat wave definitions by combining heat wave thresholds (87.5th, 90.0th, 92.5th, 95th, 97.5th, and 99th percentile of daily mean temperature) with different duration days (? 2 to ? 4 days), using Akaike information criterion for quasi-Poisson. We examined whether heat wave effects on CHD mortality were modified by heat wave duration and timing. Results Heat wave definition using 97.5th percentile of daily mean temperature (30.5 °C) and duration ? 2 days produced the best model fit. Based on this heat wave definition, we found that men and elderly were sensitive to the first heat waves of the season, while women and young were sensitive to the second heat waves. In general, the longer duration of heat waves increased the risks of CHD mortality more than shorter duration for elderly. The first two days of heat waves had the highest impact on CHD mortality. Women and elderly were at higher risks than men and young when exposed to heat waves, but the effect differences were not statistically significant. Conclusions Heat waves had significant impact on CHD mortality. This finding may have implications for policy making towards protecting human health from heat waves.

Tian, Zhaoxing; Li, Shanshan; Zhang, Jinliang; Guo, Yuming

2013-01-01

216

Effects of transportation time, distance, stocking density, temperature and lairage time on incidences of pale soft exudative (PSE) and the physico-chemical characteristics of pork.  

PubMed

The study determined the effects of transportation time, distance, stocking density, temperature and lairage time on incidences of PSE and pork quality. Frequencies of PSE cases in stocking density categories within transport duration classes were determined. General linear models, regression and the principal component (PC) analysis were used to analyse the data. Highest incidences of PSE were recorded in autumn season while lowest incidences were recorded in the spring season. Transportation time and stocking density significantly affected pHu and ultimately PSE incidences although there were no interactive effects. Highest risks of PSE occurrence were observed with more space allowance. The highest incidences of PSE were observed for animals that had travelled for two hours while the PSE cases were lower in animals that travelled for longer times. Distance travelled and transportation time had significant effects (P<0.05) on thawing loss (TL) % of pork. No relationships were reported between the other pre-slaughter variables and pork quality attributes. With the exception of transportation time and distance travelled which had a positive relationship with TL%, variation in other pre-slaughter variables did not affect meat quality variables. The risks of PSE occurrence were dependent on stocking density and transportation time. PMID:23793088

Gajana, C S; Nkukwana, T T; Marume, U; Muchenje, V

2013-11-01

217

Multifractal Analysis of the Small Time-Scale Boundary-Layer Characteristics of the Wind: the Anisotropy and Extremes  

NASA Astrophysics Data System (ADS)

Under various physical conditions (mean temperature and velocity gradients, stratification and rotation) atmospheric turbulent flows remain intrinsically anisotropic. The immediate vicinity of physical boundaries rises to a greater complexity of the anisotropy effects. In this paper we address the issue of the scaling anisotropy of the wind velocity fields within the atmospheric boundary layer (ABL). Under the universal multifractal (UM) framework we compare the small time-scale (0.1 to 1,000 seconds) boundary-layer characteristics of the wind for two different case studies. The first case study consisted of a single mast located within a wind farm in Corsica, France. Three sonic anemometers were installed on the mast at 22, 23 and 43m, measuring three-dimensional wind velocity data at 10Hz. Wakes, complex terrain and buoyancy forces influenced the measurements. The second case study (GROWIAN experiment in Germany) consisted of an array of propeller anemometers measuring wind speed inflow data at 2.5Hz over flat terrain. The propeller anemometers were positioned vertically at 10, 50, 75, 100, 125 and 150m with four horizontal measurements taken at 75, 100 and 125m. The spatial distribution allowed us to calculate the horizontal and vertical shear structure functions of the horizontal wind. Both case studies are within a kilometre from the sea. For the first case study (10Hz measurements in a wind farm test site) the high temporal resolution of the data meant we observed Kolmogorov scaling from 0.2 seconds (with intermittency correction) right up to 1,000 seconds at which point a scaling break occurred. After the break we observed a scaling power law of approximately 2, which is in agreement with Bolgiano-Obukhov scaling theory with intermittency correction. However, for the second case study (2.5Hz on flat terrain) we only observed Kolmogorov scaling from 6.4 seconds (also with intermittency correction). The spectra of horizontal velocity components remain anisotropic over high frequencies, where u1 most scales as Bolgiano-Obukhov and u2 scales as Kolmogorov. The scaling law of the vertical shears of the horizontal wind in the array varied from Kolmogorov to Bolgiano-Obukhov with height depending on the condition of stability. We interpret the results with the UM anisotropic model that greatly enhances our understanding of the ABL structure. Comparing the two case studies we found in both cases the multifractality parameter of about 1.6, which remains close to the estimates obtained for the free atmosphere. From the UM parameters, the exponent of the power law of the distribution of the extremes can be predicted. Over small scales, this exponent is of about 7.5 for the wind velocity, which is a crucial result for applications within the field of wind energy.

Fitton, G. F.; Tchiguirinskaia, I.; Schertzer, D. J.; Lovejoy, S.

2012-12-01

218

The Eect of Exposure Time to Clean Room Air on Characteristic Parameters of Au \\/Epilayer n-Si Schottky Diodes  

Microsoft Academic Search

A study has been made on determination and comparison of current-voltage (I-V) and capacitance-voltage (C-V) characteristics parameters of Au\\/n-Si Schottky barrier diodes (SBDs) with and without thin native oxide layer fabricated on n-type Si grown by LPE (Liquid-phase Epitaxy) technique. The native oxide layer with different thicknesses on chemically cleaned on Si surface were obtained by exposing the surfaces to

M. Saðlam; Ç. Nuhoðlu; E. Ayyildiz; A. Türüt; H. A. Çetýnkara

1998-01-01

219

Real-time wireless monitoring of workpiece material and debris characteristics in micro-electro-discharge machining  

Microsoft Academic Search

Wireless signals are generated with each discharge in micro-electro-discharge machining (muEDM), providing an opportunity to directly monitor discharge quality. Unlike traditional methods of monitoring progress in machining, which rely on electrical characteristics at the discharge supply terminals, this method is less affected by parasitics. The depth location of a metal-metal interface can be distinguished in the wireless signal. This is

Mark T. Richardson; Yogesh B. Gianchandani

2008-01-01

220

Performance characteristics of a real-time direct deposition gas chromatography\\/Fourier transform infrared spectrometry system  

Microsoft Academic Search

In this paper, the real-time measurement of the infrared spectra of subnanogram quantities of analytes that have been separated by gas chromatography (GC) is demonstrated for the first time. Eluites trapped as small spots on a moving window held at 77 K are passed through the beam of a Fourier transform infrared (FT-IR) spectrometer that is 100 μm square. Real-time

Sidney. Bourne; Andrew M. Haefner; Kelly L. Norton; Peter R. Griffiths

1990-01-01

221

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)

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.

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

2014-01-01

222

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

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.

Prevosto, L.; Mancinelli, B. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina)] [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina) [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina)

2013-12-15

223

A National Picture of Part-Time Community College Faculty: Changing Trends in Demographics and Employment Characteristics  

ERIC Educational Resources Information Center

Although part-time faculty continue to dominate the instructional workforce of community colleges, relatively little is known about this diverse group of individuals. Part-timers are often portrayed as being "free-way flyers" who constantly seek full-time appointments in postsecondary education institutions. However, as this article demonstrates,…

Eagan, Kevin

2007-01-01

224

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...

225

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

NASA Technical Reports Server (NTRS)

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.

Wilson, D. J.

1971-01-01

226

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

PubMed

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

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

2010-05-01

227

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

NASA Astrophysics Data System (ADS)

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/.

Vadai, Gergely; Gingl, Zoltán; Mellár, János

2012-07-01

228

Using the Selection by the Signal Time Parameters for Improvement of Spectrometric Characteristics of Heavy Ion Detectors.  

National Technical Information Service (NTIS)

The possibilities for improving the energy resolution of heavy ion semiconductor detectors and ion charge separation by means of the selection taking into account the current pulse duration are investigated. The distribution of current pulse rise time for...

A. A. Aleksandrov Y. V. Pyatkov I. A. Shlyapina V. F. Kushniruk A. V. Rykhlyuk

1984-01-01

229

Comparison of Performance Characteristics of Three Real-Time Reverse Transcription-PCR Test Systems for Detection and Quantification of Hepatitis C Virus  

Microsoft Academic Search

We evaluated the performance characteristics of three real-time reverse transcription-PCR test systems for detection and quantification of hepatitis C virus (HCV) and performed a direct comparison of the systems on the same clinical specimens. Commercial HCV panels (genotype 1b) were used to evaluate linear range, sensitivity, and precision. The Roche COBAS TaqMan HCV test for research use only (RUO) with

M. Fernanda Sabato; Mitchell L. Shiffman; Michael R. Langley; David S. Wilkinson; Andrea Ferreira-Gonzalez

2007-01-01

230

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

Microsoft Academic Search

Based on the Demand-Control-Support (DCS) model, the present paper aims to investigate the influence of job characteristics\\u000a such as job demands, job control, social support at work and self-directed learning orientation on the work-related learning\\u000a behaviour of workers. The present study was conducted in a centre for part-time vocational education in Flanders (Belgium).\\u000a The students in the centre work for

David Gijbels; Isabel Raemdonck; Dries Vervecken

2010-01-01

231

Determining the Time-Dependent Aerodynamic Characteristics by Calculating the Steady-State Flow Past Vehicles with a Modified Cross-Sectional Shape  

Microsoft Academic Search

A method of determining the time-dependent aerodynamic characteristics of flight vehicles by numerically calculating the steady-state flow past equivalent bodies is developed. The method can be rigorously validated if a hypothesis of local force interaction (in particular, the hypersonic piston analogy or the plane sections law) is adopted. The well-known curved-body method of V. V. Lunev is considerably improved by

A. V. Antonets

2003-01-01

232

A miniature UWB planar monopole antenna with 5GHz band-rejection filter and the time-domain characteristics  

Microsoft Academic Search

A planar monopole antenna with a staircase shape and small volume (25times26times1 mm3) is proposed in this paper. With the use of a half-bowtie radiating element, the staircase-shape, and a modified ground plane structure, the proposed antenna has a very wide impedance bandwidth measured at about 11.6 GHz (2.9-14.5 GHz, bandwidth ratio about 1:5) below VSWR 2 including the WLAN

Young Jun Cho; Ki Hak Kim; Dong Hyuk Choi; Seung Sik Lee; Seong-Ook Park

2006-01-01

233

Effects of Centrifugal Instabilities on Laminar/Turbulent Transition in Curved Channels with 40 to 1 Aspect Ratios.  

National Technical Information Service (NTIS)

Dean vortices in curved channels with 40 to 1 aspect ratios were measured and studied over the range of Dean numbers from 50 to 450. At low Dean numbers (50) the flow is fully laminar. At higher Dean numbers, the development of vortex pairs as the primary...

M. R. Kendall

1991-01-01

234

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

235

Dosimetric characteristics of a new polymer gel and their dependence on post-preparation and post-irradiation time: effect on X-ray beam profile measurements.  

PubMed

The aim of this study is to dosimetrically characterize a new MRI based polymer gel system and to evaluate its usefulness in clinical practice just in terms of beam profile measurements. Normoxic N-vinylpyrrolidone based polymer gel (VIPET) phantoms were produced and used in order to perform three main sets of experiments: a) dose-response evaluation and reproducibility experiments, b) experiments for the evaluation of sensitivity of dose characteristics on 'gel manufacture - irradiation' time interval and c) experiments for the evaluation of sensitivity of dose characteristics on 'irradiation - MRscanning' time interval. It has been shown that this gel system can be used in a wide dose-range of 0-60 Gy. It exhibits a linear dose-response in the dose-range of 2-35 Gy. Following the proposed manufacturing method the dose-response characteristics are reproducible. Moreover, it seems that the optimum 'gel manufacturing - irradiation' time interval is 1 day. However, a 'gel manufacturing - irradiation' time interval up to ?1 week can be safely used. The optimum 'irradiation - MRscanning' time interval in terms of dose-response sensitivity and dose resolution can be reliably ranged from 1 day to 3 weeks. Finally, X-ray beam profile gel-measurements were performed and found to be in satisfying agreement with corresponding small sensitive volume ion chamber measurements. VIPET gel dosimeters preserved the spatial integrity of the dose distribution during a time period of 50 days post-irradiation. The studied gel system can be safely used in clinical practice within the practical limitations found and described in this work. PMID:23375524

Papoutsaki, Marianthi-Vasiliki; Maris, Thomas G; Pappas, Evangelos; Papadakis, Antonios E; Damilakis, John

2013-09-01

236

Selected ovarian ultrasonographic characteristics during vernal transition are useful to estimate time of first ovulation of the year.  

PubMed

It is important to get mares pregnant as early as possible after vernal transition and thus, identification signs of impending 1st ovulation of the year are warranted. To identify clinical indicators of an approaching first ovulation of the year, mares were teased with a stallion for oestrous detection starting January 3 and subjected to ultrasonographic examination. Day of first appearance of uterus oedema, follicular wall invagination, intrafollicular echogenicity, double contour of the follicle wall, increase in granulosa thickness, follicular wall hyperechogenicity and appearance of pear-shaped follicles was registered, as well as follicle diameter and number. Seventy per cent of the mares had anovulatory oestrous periods of 4.6 ± 3.6 days, with an interoestroual interval of 12.5 ± 12.2 days. Number of anovulatory oestruses per mare was 2.4 ± 2.3. Uterine oedema occurred in 77% of the mares, 32.4 ± 25.6 days before ovulation. Invagination of the follicular wall appeared in 44.4% of the animals, 24.5 ± 18.4 days before ovulation. Intrafollicular echogenicity was seen in all mares and double contour of the follicle was seen in 77% of the animals. Both last two characteristics appeared 1-72 days before ovulation. Increased thickness of the granulosa occurred in 66% of the mares, 1-19 days before ovulation. Pear-shaped follicles and follicular wall hyperechogenicity were detected 3 or less days before the first ovulation, in 44.4% and 55.5% of mares, respectively. Mean number of follicles > 15 mm decreased at least 16 days before ovulation. We concluded that no isolated characteristic was a reliable indicator. However, increase in granulosa thickness, formation of a pear-shaped follicle and follicular wall hyperechogenicity, associated with the reduction of the number of follicles > 15 mm in diameter to < 3, resulted in the first ovulation of the year in 44-67% of the transitional mares, 1-19 days after the characteristics appeared. PMID:20825584

Atayde, Lm; Rocha, A

2011-04-01

237

Characteristics of THz carrier dynamics in GaN thin film and ZnO nanowires by temperature dependent terahertz time domain spectroscopy measurement  

NASA Astrophysics Data System (ADS)

We present a comprehensive study of the characteristics of carrier dynamics using temperature dependent terahertz time domain spectroscopy. By utilizing this technique in combination with numerical calculations, the complex refractive index, dielectric function, and conductivity of n-GaN, undoped ZnO NWs, and Al-doped ZnO NWs were obtained. The unique temperature dependent behaviors of major material parameters were studied at THz frequencies, including plasma frequency, relaxation time, carrier concentration and mobility. Frequency and temperature dependent carrier dynamics were subsequently analyzed in these materials through the use of the Drude and the Drude-Smith models.

Balci, Soner; Baughman, William; Wilbert, David S.; Shen, Gang; Kung, Patrick; Kim, Seongsin Margaret

2012-12-01

238

Variations of soil profile characteristics due to varying time spans since ice retreat in the inner Nordfjord, western Norway  

NASA Astrophysics Data System (ADS)

In the Erdalen and Bødalen drainage basins located in the inner Nordfjord in western Norway the soils have been formed after deglaciation. The climate in the uppermost valley areas is sub-arctic oceanic and the lithology consists of Precambrian granitic orthogneisses on which Leptosols and Regosols are the most common soils. The Little Ice Age glacier advance affected parts of the valleys with the maximum glacier extent around AD 1750. In this study five sites on moraine and colluvium materials were selected to examine the main soil properties to assess if soil profile characteristics and pattern of fallout radionuclides (FRNs) and environmental radionuclides (ERNs) are affected by different stages of ice retreat. The Leptosols on the moraines are shallow, poorly developed and vegetated with moss and small birches. The two selected profiles show different radionuclide activities and grain size distribution. The sampled soils on the colluviums outside the LIA glacier limit became ice-free during the Preboral. The Regosols present better-developed profiles, thicker organic horizons and are fully covered by grasses. Activity of 137Cs and 210Pbex concentrate at the topsoil and decrease sharply with depth. The grain size distribution of these soils also reflects the difference in geomorphic processes that have affected the colluvium sites. Significant lower mass activities of FRNs are found in soils on the moraines than on colluviums. Variations of ERNs activities in the valleys are related to characteristics soil mineralogical composition. These results indicate differences in soil development that are consistent with the age of ice retreat. In addition, the pattern distribution of 137Cs and 210Pbex activities differs in the soils related to the LIA glacier limits in the drainage basins.

Navas, A.; Laute, K.; Beylich, A. A.; Gaspar, L.

2014-01-01

239

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

NASA Technical Reports Server (NTRS)

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.

Williams, Peter E.; Pesnell, William Dean

2012-01-01

240

Variations of soil profile characteristics due to varying time spans since ice retreat in the inner Nordfjord, western Norway  

NASA Astrophysics Data System (ADS)

In the Erdalen and Bødalen drainage basins located in the inner Nordfjord in western Norway the soils were formed after deglaciation. The climate in the uppermost valley areas is sub-arctic oceanic, and the lithology consists of Precambrian granitic orthogneisses on which Leptosols and Regosols are the most common soils. The Little Ice Age glacier advance affected parts of the valleys with the maximum glacier extent around AD 1750. In this study five sites on moraine and colluvium materials were selected to examine main soil properties, grain size distribution, soil organic carbon and pH to assess if soil profile characteristics and patterns of fallout radionuclides (FRNs) and environmental radionuclides (ERNs) are affected by different stages of ice retreat. The Leptosols on the moraines are shallow, poorly developed and vegetated with moss and small birches. The two selected profiles show different radionuclide activities and grain size distribution. The sampled soils on the colluviums outside the LIA glacier limit became ice-free during the Preboral. The Regosols present better-developed profiles, thicker organic horizons and are fully covered by grasses. Activity of 137Cs and 210Pbex concentrate at the topsoil and decrease sharply with depth. The grain size distribution of these soils also reflects the difference in geomorphic processes that have affected the colluvium sites. Significantly lower mass activities of FRNs were found in soils on the moraines than on colluviums. Variations of ERN activities in the valleys were related to characteristics of soil mineralogical composition. These results indicate differences in soil development that are consistent with the age of ice retreat. In addition, the pattern distribution of 137Cs and 210Pbex activities differs in the soils related to the LIA glacier limits in the drainage basins.

Navas, A.; Laute, K.; Beylich, A. A.; Gaspar, L.

2014-06-01

241

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

242

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

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

243

Effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover using combination of steam explosion and microwave irradiation (SE-MI) pretreatment.  

PubMed

The effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover were investigated based on a new process named combination of steam explosion and microwave irradiation (SE-MI) pretreatment. Results showed that with microwave power and microwave irradiation time increasing, glucose and xylose that released into hydrolyzate, as well as enzymatic hydrolysis yields and sugar yields of glucose and xylose were all slightly increased after SE-MI pretreatment. The maximum sugar yield was 72.1 g per 100 g glucose and xylose in feedstock, achieved at 540 W microwave power and 5 min microwave irradiation time. XRD analysis showed that the crystallinity of biomass was 15.6-19.9% lower for SE-MI pretreatment with microwave effect than that without microwave effect. However, low microwave power and short microwave irradiation time were favorable for SE-MI pretreatment considering energy consumption. PMID:22705513

Pang, Feng; Xue, Shulin; Yu, Shengshuan; Zhang, Chao; Li, Bing; Kang, Yong

2012-08-01

244

Socio-demographic and other patient characteristics associated with time between colonoscopy and surgery, and choice of treatment centre for colorectal cancer: a retrospective cohort study  

PubMed Central

Objectives To investigate key patient clinical and demographic characteristics associated with time between colonoscopy and surgery, and choice of treatment centre for colorectal cancer (CRC) patients. This will add to the little published research examining the pathway following CRC diagnosis and prior to surgery. Design Retrospective cohort analysis of linked data. Setting A population-based sample of people diagnosed August 2004 to December 2007 in New South Wales, Australia. Participants 569 CRC patients, of whom 407 (72%, 95% CI 68% to 75%) had colonoscopy followed by surgery. Primary outcome measures Time between colonoscopy and surgery, and whether the surgery took place in a specialist cancer centre. Results Among the 407 eligible patients analysed, the median time from colonoscopy to surgery was 19?days (IQR 12–29?days). After adjusting for key demographic and clinical characteristics such as age and disease stage, the time was longer for rectal cancer patients and those reporting fair/poor health, although differences in medians were <5?days. 24% (95% CI 20% to 28%) had surgery in a specialist cancer centre, which was more common among people resident in metropolitan areas (37% vs 14% for others, adjusted p=0.001) and those without private health insurance (30% vs 21% for others, adjusted p=0.03). Conclusions There do not appear to be systemic issues affecting time from colonoscopy to surgery related to patients' socio-demographic characteristics. However, patients with private insurance and those living in rural areas may be less likely to receive optimal specialist treatment. A more systematic approach might be needed to ensure cancer patients are treated in specialist cancer centres, particularly patients requiring more specialised treatment.

Harris, Mark Fort; Pascoe, Shane; Olver, Ian; Barton, Michael; Spigelman, Allan; O'Connell, Dianne

2012-01-01

245

Analysis of robust design experiments with time-dependent ordinal response characteristics: a quality improvement study from the horticulture industry  

Microsoft Academic Search

An approach to the analysis of time-dependent ordinal quality score data from robust design experiments is developed and applied to an experiment from commercial horticultural research, using concepts of product robustness and longevity that are familiar to analysts in engineering research. A two-stage analysis is used to develop models describing the effects of a number of experimental treatments on the

N. R. Parsons; S. G. Gilmour; R. N. Edmondson

2009-01-01

246

Implementation of gas sampling chamber and measuring hardware for capnograph system considering thermal noise effect and time response characteristics  

Microsoft Academic Search

Most capnograph systems that can indirectly determine the partial pressure of carbon dioxide in the blood of a patient are based on NDIR (non-dispersive infrared) absorption technology. As such an NDIR gas analyzing method requires an optical absorption chamber and signal processing hardware. Accordingly, this paper designed and implemented an NDIR type CO2 gas chamber while considering the time response

I. Y. Park; S. K. Lee; H. J. Park; K. M. Kang; B. S. Song; S. W. Kang; J. H. Cho

2001-01-01

247

Changes in characteristics of soluble microbial products in membrane bioreactors associated with different solid retention times: Relation to membrane fouling  

Microsoft Academic Search

A membrane bioreactor (MBR) is a promising wastewater treatment technology, but there is a need for efficient control of membrane fouling, which increases operational and maintenance costs. Soluble microbial products (SMP) have been reported to act as major foulants in the operation of MBRs used for wastewater treatment. In this study, SMP in MBRs operated with different sludge retention times

Katsuki Kimura; Takuro Naruse; Yoshimasa Watanabe

2009-01-01

248

Effects of feeding intensity and time on feed on performance, carcass characteristics and meat quality of Simmental bulls  

Microsoft Academic Search

Seventy two Simmental bulls, weighing 489 kg and approximately 15 months old fed extensively or intensively on maize silage and concentrate mixture for 100 or 138 days, were divided into four groups to assess the effect of time on feed and feeding intensity on the performance, carcass and meat quality traits. Bulls intensively fed for 138 days before slaughter had

A. S. Sami; C. Augustini; F. J. Schwarz

2004-01-01

249

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

250

Real time monitoring of the impedance characteristics of Staphylococcal bacterial biofilm cultures with a modified CDC reactor system.  

PubMed

Detection of device-associated infectious processes is still an important clinical challenge. Bacteria grow adhered to the device surfaces creating biofilms that are resistant to antimicrobial agents, increasing mortality and morbidity. Thus there is need of a surgical procedure to remove the indwelling infected device. The elevated cost of these procedures, besides patients discomfort and increased risks, highlights the need to develop more efficient, accurate and rapid detection methods. Biosensors integrated with implantable devices will provide an effective diagnostic tool. In vivo, rapid and sensitive detection of bacteria attached to the device surfaces will allow efficient treatments. Impedance spectroscopy technique would be an adequate tool to detect the adherence and the growth of the microorganism by monitoring the impedance characteristics. In this work a label-free interdigitated microelectrode (IDAM) biosensor has been developed to be integrated with implantable devices. Impedance characterization of Staphylococcus epidermidis biofilms has been performed achieving electrical monitoring of the bacterial growths in a few hours from the onset of the infection. This pathogen represents the most common microorganism related to intravascular catheters associated infections. The experimental setup presented in this work, a modified CDC biofilm reactor, simulates the natural environment conditions for bacterial biofilm development. The results prove that the low range of frequency is the most suitable setting for monitoring biofilm development. Our findings prove the effectiveness of this technique which shows variations of 59% in the equivalent serial capacitance component of the impedance. PMID:22705402

Paredes, J; Becerro, S; Arizti, F; Aguinaga, A; Del Pozo, J L; Arana, S

2012-01-01

251

Interaural cross-correlation coefficient, apparent source width, and time/frequency characteristics of binaural running cross-correlation  

NASA Astrophysics Data System (ADS)

The interaural cross-correlation coefficient (IACC) descriptors attempt to characterize in a single number the binaural cross-correlation function at the expense of losing much detail in a manner similar to, but more problematic than, such descriptors as NC, STC, and NRC because much frequency- and rich time-domain information is lost. Recent computer simulations by Mason illuminated these problems and further stimulated the present study. Old binaural impulse recordings run through an analog computer algorithm (drawn from physiological modeling) were re-examined in an attempt to reveal trends and relationships that the current descriptors cannot. Issues of the time and frequency variance of the measured running coefficient are discussed in terms of apparent source width (ASW) for music in Troy Music Hall and simpler spaces.

Conant, David A.

2004-10-01

252

Study on characteristics of CdS quantum dot-sensitized solar cells prepared by successive ionic layer adsorption and reaction with different adsorption times  

NASA Astrophysics Data System (ADS)

Cadmium sulfide (CdS) quantum dots (QDs) were adsorbed on a titanium dioxide (TiO2) nanoporous film by successive ionic layer adsorption and reaction (SILAR) method with different adsorption times to study the influences of different SILAR adsorption times on CdS quantum dot-sensitized solar cells (QDSCs). The optical properties of CdS sensitized TiO2 films were studied by scanning electron microscopy and UV-Vis absorbance spectroscopy. The particle size of the CdS QDs was approximated using the effective mass approximation theory from the absorbance spectra. The photovoltaic characteristics of the CdS QDSCs were analyzed by I- V characteristics and electrochemical impedance spectroscopy under air mass 1.5 illumination. As a result, the particle size of the CdS QDs became larger and light harvesting was enhanced with increasing SILAR adsorption time. The maximum photovoltaic conversion efficiency of the CdS QDSCs (1.86%) was obtained at the SILAR adsorption time of 30 min with the highest short circuit current density and lowest charge transfer resistance.

Jeong, Myeong-Soo; Son, Min-Kyu; Kim, Soo-Kyoung; Park, Songyi; Prabakar, Kandasamy; Kim, Hee-Je

2014-05-01

253

A Methodology for Flight-Time Identification of Helicopter-Slung Load Frequency Response Characteristics Using CIFER  

NASA Technical Reports Server (NTRS)

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.

Sahai, Ranjana; Pierce, Larry; Cicolani, Luigi; Tischler, Mark

1998-01-01

254

The design and characteristic features of a new time-of-flight mass spectrometer with a spiral ion trajectory  

Microsoft Academic Search

A new time-of-flight (TOF) mass spectrometer with a corkscrew ion trajectory was designed and constructed. The spiral trajectory\\u000a was realized by using four toroidal electrostatic sectors. Each had fifteen-stories made of sixteen Matsuda plates piled up\\u000a inside a cylindrical electrostatic sector. The ions passed the four toroidal electrostatic sectors sequentially and revolved\\u000a along a figure-eight-shaped orbit on a certain projection

Takaya Satoh; Hisayuki Tsuno; Mitsuyasu Iwanaga; Yoshihiro Kammei

2005-01-01

255

Effects of the hydraulic retention time on the fouling characteristics of an anaerobic membrane bioreactor for treating acidifi ed wastewater  

Microsoft Academic Search

This study focused on the effect of hydraulic retention time (HRT) effect on microbial activity and fouling potential in submerged anaerobic membrane bioreactors (AMBRs).Three submerged AMBRs were operated at HRT of 14, 16, and 20 days with polypropylene U-shaped hollow fiber microfiltration membranes (nominal pore size = 0.45 ?m; effective filtration area = 0.003 m2). Extracellular polymeric substances (EPS) and

Emma Jeong; Hyun-Woo Kim; Joo-Youn Nam; Yong-Tae Ahn; Hang-Sik Shin

2010-01-01

256

Latino Identity of First-time Immigrants in the Philadelphia Area: What are its Characteristics and How Does it Develop?  

Microsoft Academic Search

The paper explores the question of how Hispanic\\/Latino identity develops among first-time immigrants to the U.S. living in the Philadelphia area. This exploration was done through an extensive review of the current literature and by carrying out in-depth interviews with six individuals who were at least eighteen years old and diverse in terms of gender and countries of origin. Two

Sarvelia Nonantzin Peralta-Duran

2007-01-01

257

Growth characteristics of human adipose-derived stem cells during long time culture regulated by cyclin a and cyclin D1.  

PubMed

Abundant and less passaged cells are highly expected in clinical application since repeated subculture reduces stem cell characteristics. Long time culture of stem cells without passage is therefore needed. The growth and cell viability of human adipose-derived stem cells (hADSCs) were investigated by live/dead staining, cck-8 kits, and hemocytometer every day in 30 days of culture. The stem cell characteristics of hADSCs at the beginning and the end of culture were detected by flow cytometry and histochemical staining. hADSCs can be cultured up to the 30th day in one passage while maintaining high level cell viability and their stem cell characteristics. In addition, the cells displayed two plateau phases and three logarithmic phases during 1 month of culture. Increasing expression of cyclin A at protein level resulted in an increase in the percentage of hADSCs in the S and G(2)/M phases, while decreasing protein level of cyclin D1 induced a decline in the proportion of hADSCs in the G(0)/G(1) phase, regulating cells to move into rapid proliferation. This study demonstrates that a great quantity of hADSCs can be obtained in vitro by prolonging the culture time of each passage. And cyclin A and cyclin D1 affect the distribution of cell cycle and regulate the growth of hADSCs. PMID:23076572

Jiang, Lili; Liu, Tianqing; Song, Kedong

2012-12-01

258

Effects of different lairage times after long distance transportation on carcass and meat quality characteristics of Hungarian Simmental bulls.  

PubMed

The objective of this study was to determine the effects of three lairage times (24 h, 48 h and 72 h) on the meat quality of tame trained to lead Hungarian Simmental bulls subjected to long commercial transportation of approximately 1800 km. A total of 30 bulls, with an average age of 24 months, were used. During the lairage, bulls received 0.5 kg concentrate feed per animal per day and ad libitum access to the hay and water. As the lairage duration increased, the pH(ult) decreased (P<0.05). Bulls lairaged for 24 h had lower L*, b* and H* values than those lairaged for 48 h and 72 h (P<0.05). The effect of lairage time on WHC, cooking loss and Warner-Bratzler shear force values was not significant. The b* value was considered the best predictor of muscle pH(ult). In conclusion, 72 h quiet lairage time is recommended after transportation in order to prevent the adverse effects of transportation on meat quality. PMID:23916957

Teke, Bulent; Akdag, Filiz; Ekiz, Bulent; Ugurlu, Mustafa

2014-01-01

259

Characteristics of official and experimental GRACE time series by GFZ and CSR - with applications to polar signals  

NASA Astrophysics Data System (ADS)

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.

Horvath, Alexander; Horwath, Martin; Pail, Roland

2014-05-01

260

X-ray spectral and timing characteristics of the stars in the young open cluster IC 2391  

NASA Astrophysics Data System (ADS)

We present X-ray spectral and timing analysis of members of the young open cluster IC 2391 observed with the XMM-Newton observatory. We detected 99 X-ray sources by analysing the summed data obtained from MOS1, MOS2 and pn detectors of the EPIC camera; 24 of them are members, or probable members, of the cluster. Stars of all spectral types have been detected, from the early-types to the late-M dwarfs. Despite the capability of the instrument to recognize up to 3 thermal components, the X-ray spectra of the G, K and M members of the cluster are well described with two thermal components (at kT1 ˜ 0.3-0.5 keV and kT2 ˜ 1.0-1.2 keV respectively) while the X-ray spectra of F members require only a softer 1-T model. The Kolmogorov-Smirnov test applied to the X-ray photon time series shows that approximately 46% of the members of IC 2391 are variable with a confidence level >99%. The comparison of our data with those obtained with ROSAT/PSPC, nine years earlier, and ROSAT/HRI, seven years earlier, shows that there is no evidence of significant variability on these time scales, suggesting that long-term variations due to activity cycles similar to that on the Sun are not common, if present at all, among these young stars.

Marino, A.; Micela, G.; Peres, G.; Pillitteri, I.; Sciortino, S.

2005-01-01

261

A mixed effects model to estimate timing and intensity of pubertal growth from height and secondary sexual characteristics  

PubMed Central

Aim To estimate and compare pubertal growth timing and intensity in height, Tanner stage markers and testis volume. Subjects and methods Data on height, genital stage, breast stage and pubic hair stage, testis volume and menarche in 103 boys and 74 girls from the Edinburgh Longitudinal Growth Study were analysed. The SITAR model for height and a novel mixed effects logistic model for Tanner stage and testis volume provided estimates of peak velocity (PV, intensity) and age at peak velocity (APV, timing), both overall (from fixed effects) and for individuals (random effects). Results Based on the six markers, mean APV was 13.0–14.0 years in boys and 12.0–13.1 years in girls, with between-subject standard deviations of ?1 year. PV for height was 8–9?cm/year by sex and for testis volume 6?ml/year, while Tanner stage increased by 1.2–1.8 stages per year at its peak. The correlations across markers for APV were 0.6–0.8 for boys and 0.8–0.92 for girls, very significantly higher for girls (p?=?0.005). Correlations for PV were lower, ?0.2–0.6. Conclusions The mixed effects models perform well in estimating timing and intensity in individuals across several puberty markers. Age at peak velocity correlates highly across markers, but peak velocity less so.

Pan, H.; Butler, G. E.

2014-01-01

262

X-ray Variability Characteristics of the Narrow line SEYFERT 1 MKN 766 I: Energy Dependent Timing Properties  

NASA Technical Reports Server (NTRS)

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.

Markowitz, A.; Turner, T. J.; Papadakis, I.; Arevalo, P.; Reeves, J. N.; Miller, L.

2007-01-01

263

Calibrating passive acoustic monitoring: correcting humpback whale call detections for site-specific and time-dependent environmental characteristics.  

PubMed

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

Helble, Tyler A; D'Spain, Gerald L; Campbell, Greg S; Hildebrand, John A

2013-11-01

264

The Effect of Etching Time on Rectifying Characteristic in SnO2/p-Si and SnO2/p-PoSi Heterojunction Schottky Diodes  

NASA Astrophysics Data System (ADS)

We have fabricated SnO2/p-Si and SnO2/p-PoSi heterojunction diodes by spray pyrolysis method. To prepare porous Si substrates, the etching time was varied from 10 to 20 and 30 mins. In these samples, the SEM micrographs showed a distributed pore areas surrounded by columnar walls with various height. The data analysis of the rectified I-V characteristic, using thermionic emission Schottky diode theory, showed that although the barrier height is about 0.5-0.6 eV in all samples other two important diode parameters, i.e. the ideality factor n and the series resistance rs, are strongly etching time-dependant and are increased with increasing the etching time.

Biaram, Alireza; Eshghi, Hosein

2013-03-01

265

Effects of cutting time, stump height, parent tree characteristics, and harvest variables on development of bigleaf maple sprout clumps  

USGS Publications Warehouse

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.

Tappeiner, J. C., II; Zasada, J.; Maxwell, B.; Maxwell, B.

1996-01-01

266

Structural characteristic of folding/unfolding intermediate of pokeweed anti-viral protein revealed by time-resolved fluorescence.  

PubMed

The structural feature of unfolding intermediate of pokeweed anti-viral protein (PAP) was characterized using time-resolved fluorescence spectroscopic methods to elucidate protein folding/unfolding process. CD and fluorescence spectra consistently demonstrated that the unfolding of PAP completed at 4 M of guanidine hydrochloride (GuHCl). The fluorescence resonance energy transfer (FRET) and time-resolve fluorescence depolarization analysis of Trp208 and Trp237 located in the C-terminal domain of PAP suggested that peculiar unfolding intermediate populated before reaching to the unfolding state. The FRET distance of Trp237 to Tyr182 was extended to more than 28 Å with keeping the compact conformation in the unfolding intermediate state populated in the presence of 2 M GuHCl. On the other hand, Trp208 maintained the energy transfer pair with Tyr72 near the active site, although the rotational freedom was increased a little. There results suggest that the most distinguished structural feature of the unfolding intermediate of PAP is the separation of C-terminal domain from N-terminal domain. FRET and fluorescence depolarization studies also showed that C-terminal domain would be more separated to liberate the segmental motions of Trp208 and Trp237 distinctly at the unfolding state. PMID:23319009

Matsumoto, Shuzo; Taniguchi, Yuka; Fukunaga, Yukihiro; Nakashima, Hiromichi; Watanabe, Keiichi; Yamashita, Shoji; Nishimoto, Etsuko

2013-05-01

267

The Energy-Dependent X-Ray Timing Characteristics of the Narrow Line Seyfert 1 MKN 766  

NASA Technical Reports Server (NTRS)

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.

Markowitz, A.; Papadakis, I.; Arevalo, P.; Turner, T. J.; Miller, L.; Reeves, J. N.

2007-01-01

268

Treatment-time regimen of hypertension medications significantly affects ambulatory blood pressure and clinical characteristics of patients with resistant hypertension.  

PubMed

Patients with resistant hypertension (RH) are at greater risk for stroke, renal insufficiency, and cardiovascular disease (CVD) events than are those for whom blood pressure (BP) is responsive to and well controlled by therapeutic interventions. Although all chronotherapy trials have compared the effects on BP regulation of full daily doses of medications when ingested in the morning versus at bedtime, prescription of the same medications in divided doses twice daily (BID) is frequent. Here, we investigated the influence of hypertension treatment-time regimen on the circadian BP pattern, degree of BP control, and relevant clinical and laboratory medicine parameters of RH patients evaluated by 48-h ambulatory BP monitoring (ABPM). This cross-sectional study evaluated 2899 such patients (1701 men/1198 women), 64.2?±?11.8 (mean?±?SD) yrs of age, enrolled in the Hygia Project. Among the participants, 1084 were ingesting all hypertension medications upon awakening (upon-awakening regimen), 1436 patients were ingesting the full daily dose of ?1 of them at bedtime (bedtime regimen), and 379 were ingesting split doses of ?1 medications BID upon awakening and at bedtime (BID regimen). Patients of the bedtime regimen compared with the other two treatment-time regimens had lower likelihood of microalbuminuria and chronic kidney disease; significantly lower albumin/creatinine ratio, glucose, total cholesterol, and low-density lipoprotein (LDL) cholesterol; plus higher estimated glomerular filtration rate and high-density lipoprotein (HDL) cholesterol. The bedtime regimen was also significantly associated with lower asleep systolic (SBP) and diastolic (DBP) BP means than the upon-awakening and BID regimens. The sleep-time relative SBP and DBP decline was significantly attenuated by the upon-awakening and BID regimens (p?time regimen groups (80.5% and 77.3%, respectively) than in the bedtime regimen (54.4%; p?

Hermida, Ramón C; Ríos, María T; Crespo, Juan J; Moyá, Ana; Domínguez-Sardiña, Manuel; Otero, Alfonso; Sánchez, Juan J; Mojón, Artemio; Fernández, José R; Ayala, Diana E

2013-03-01

269

Over time and space changing characteristics of estuarine suspended particles in the German Weser and Elbe estuaries  

NASA Astrophysics Data System (ADS)

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.

Papenmeier, Svenja; Schrottke, Kerstin; Bartholomä, Alexander

2014-01-01

270

Influence of reaction time and temperature on product formation and characteristics associated with the hydrothermal carbonization of cellulose.  

PubMed

Studies have demonstrated that hydrothermal carbonization of biomass and waste streams results in the formation of beneficial materials/resources with minimal greenhouse gas production. Data necessary to understand how critical process conditions influence carbonization mechanisms, product formation, and associated environmental implications are currently lacking. The purpose of this work is to hydrothermally carbonize cellulose at different temperatures and to systematically sample over a 96-h period to determine how changes in reaction temperature influence product evolution. Understanding cellulose carbonization will provide insight to carbonization of cellulosic biomass and waste materials. Results from batch experiments indicate that the majority of cellulose conversion occurs between the first 0.5-4h, and faster conversion occurs at higher temperatures. Data collected over time suggest cellulose solubilization occurs prior to conversion. The composition of solids recovered after 96h is similar at all temperatures, consisting primarily of sp(2) carbons (furanic and aromatic groups) and alkyl groups. PMID:23612178

Lu, Xiaowei; Pellechia, Perry J; Flora, Joseph R V; Berge, Nicole D

2013-06-01

271

Learning new movement patterns: a study on good and poor writers comparing learning conditions emphasizing spatial, timing or abstract characteristics.  

PubMed

In the earliest stages of motor-skill learning cognitive, visuo-spatial and dynamic processes play an important role. Which of these should be addressed first when children need to learn a new complex movement sequence? This study compares three learning methods in a within-subject design by having 18 good and 18 poor 8-year-old writers master unfamiliar, letter-like patterns by (1) tracing a trajectory on a screen, (2) tracking a moving target (pursuit), and (3) performing the pattern using written explicit instructions. Following each 10-trial learning phase, the children completed a short test phase. Besides errors and kinematic data, Dynamic Time Warping (DTW) was used to calculate the deviation for each pattern from the ideal shape (DTW-distance). As predicted, the number of errors and DTW-distance were very low during the learning phase of the tracing and pursuit conditions and higher in the explicit condition. Conversely, in the test phase, tracing yielded the highest DTW-distance and the explicit condition the lowest DTW-distance and error percentages. The results were remarkably similar for the good and poor writers. The poor learning results of the tracing condition and the good results of the explicit condition have important implications for the teaching of handwriting and remedial therapy. PMID:21185098

Overvelde, Anneloes; Hulstijn, Wouter

2011-08-01

272

Real-time digital data-acquisition system for determining load characteristics. Volume 2: Operating, programming and maintenance instructions  

NASA Astrophysics Data System (ADS)

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.

Podesto, B.; Lapointe, A.; Larose, G.; Robichaud, Y.; Vaillancourt, C.

1981-03-01

273

Characteristics of ion components and trace elements of fine particles at Gosan, Korea in spring time from 2001 to 2002.  

PubMed

Size-segregated measurements of the composition of an aerosol are used to determine the transport of natural and anthropogenic aerosols to the Gosan site in springtime from 2001 to 2002. Although the transport of Asian dust is a well-known phenomenon in springtime, this study shows that not only is soil dust transported into Gosan each spring but so are anthropogenic aerosols, including sulfur, enriched trace metals such as Pb, Zn, Ni, K, S. This study also combines the size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories in order to identify some potential source regions of the anthropogenic aerosols. Finally, four types of transport episodes were identified: (1) anthropogenic pollutants, (2) dust storm mixed with the anthropogenic aerosols, (3) typical dust storms, (4) some sea salt with clean air mass. Overall, in addition to typical soil dust, a large amount of anthropogenic aerosols, whether mixed with the soil dust or not, are transported to Gosan each spring. PMID:15038537

Han, J S; Moon, K J; Ahn, J Y; Hong, Y D; Kim, Y J; Ryu, S Y; Cliff, S S; Cahill, T A

2004-03-01

274

Global Characteristics of the Correlation and Time Lag Between Solar and Ionospheric Parameters in the 27-day Period  

NASA Technical Reports Server (NTRS)

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.

Lee, Choon-Ki; Han, Shin-Chan; Dieter,Bilitza; Ki-Weon,Seo

2012-01-01

275

The prevalence of PSE characteristics in pork and cooked ham--effects of season and lairage time.  

PubMed

A total of 180 pigs was slaughtered in the same slaughterhouse, but divided in six different trials distributed over Winter (December-March) and Summer (April-September). Meat quality measurements (pH, electrical conductivity, color and/or water-holding capacity) were carried out 30 min, 24 and/or 35h after slaughter in three different muscles: M. gracilis, M. semimembranosus and M. longissimus dorsi. A tendency towards a higher proportion of PSE meat during Summer was found in the examined muscles. Moreover a higher protein, higher dry matter content, a lower water/protein ratio and a lower slicing yield were found for the cooked hams suggesting a higher PSE prevalence in the Summer. A lairage time between 2 and 4h during Summer and less than 2h during Winter was related to a lower proportion of PSE meat. The correlation coefficients between the individual meat quality variables were moderate, but showed the predictive power of the pH measured 24h post-mortem in the M. gracilis for meat quality. PMID:20554397

Van de Perre, V; Ceustermans, A; Leyten, J; Geers, R

2010-10-01

276

Seismicity, arrival time delays of the seismic phases and slowness characteristics study in Abu Dabbab area, Egypt  

NASA Astrophysics Data System (ADS)

The temporal variations of seismicity from the Abu Dabbab area, 25 km west of the Red Sea coast, are collected from the Egyptian national seismic network (ENSN), which has magnified the detection capability in that area to ML < 1 earthquakes. These data show a sequence of the micro earthquake swarm during 2003-2011. This area has experienced larger shocks up to M = 6 during the 20th century and its seismicity is concentrated in a narrow spatial volume. We analyze the digital waveform data of about 1000 seismograms, recorded by portable network of 10 vertical component seismographs that are employed in a temporary survey experiment in the Abu Dabbab area in 2004, and the results indicate: firstly, there are similar waveform seismograms, which are classified into three groups. In each group a master event is identified. Then, the arrival time delays of the P and S phases (?tp and ?ts, respectively) are measured between the master event and its slave events. ?tp and ?ts range between -0.01 and 0.02 s, respectively. These values are used to relocate the studied events. Secondly, the slowness vector (?s) in 3-dimensional pattern, which is estimated using the genetic algorithms, is found ?sx = 0.0153, ?sy = 0.00093 and ?sz = 0.2086 s/km in the three spatial coordinates (X, Y and Z), respectively. These analyses demonstrate the inhomogeneities within the upper crust of the study area. Also, ?s shows little dependence of lateral distances and reasonably high slowness along the depth extent, which is consistent with the seismic velocity structure variations.

Sami, Mahmoud; Hassoup, Awad; Hosny, Ahmed; Mohamed, Gadelkarem A.

2013-12-01

277

Clinical characteristics of patients with type 2 diabetes mellitus at the time of insulin initiation: INSTIGATE observational study in Spain  

PubMed Central

Little information is available on the management of patients with type 2 diabetes mellitus (DM2) in regular clinical practice, prior to and at the point of initiating treatment with insulin. The INSTIGATE study provides a description of the clinical profile of the patient with DM2 who begins treatment with insulin in both primary and secondary care. A total of 224 patients who had been diagnosed with DM2, were not responding to oral treatment, and began receiving insulin were included in the INSTIGATE study in Spain. Demographic data were collected, as well as data on macro- and microvascular complications of diabetes and comorbidities, past medical history of diabetes and oral treatment administered, the clinical severity of diabetes (HbA1c concentration) and insulin treatment initiated. Mean age of the sample was 65.4 years and 56.7% were men. There were 87% of patients who had a diagnosis of at least one significant comorbidity, notably hypertension and hyperlipidemia. The patient profile for metabolic syndrome was met by 75.1% of the patients. There was a higher incidence of macrovascular complications (38.4%) than microvascular complications (16.1%). Prior to insulin initiation, the most recent mean HbA1c was 9.2%. The majority of patients had been treated in the last 12 months with sulfonylureas and/or metformin (69.6 and 57.6%). The most common treatment prior to insulinization was the co-administration of two oral antidiabetics (OADs) (37.5%). Patients with DM2 observed in the study presented with elevated mean HbA1c and body mass index levels, comorbidities and complications related to diabetes at the time of insulin initiation. Changes and adjustments in treatment from diagnosis of diabetes occur when HbA1c levels are far above those recommended by the IDF (International Diabetes Federation), a factor which could be contributing to the development of both macrovascular and microvascular complications in the patient profile described in the study.

Dilla, Tatiana; Reviriego, Jesus; Castell, Conxa; Goday, Albert

2009-01-01

278

Effect of gamma irradiation and storage time on microbial growth and physicochemical characteristics of pumpkin (Cucurbita Moschata Duchesne ex Poiret) puree.  

PubMed

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 25°C?. 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 20°C?. As a result, the shelf-life of purees increased to 28 days. PMID:23733817

Gliemmo, María F; Latorre, María E; Narvaiz, Patricia; Campos, Carmen A; Gerschenson, Lía N

2014-01-01

279

Study on hydrofluoric acid-based clad etching and chemical sensing characteristics of fiber Bragg gratings of different reflectivity fabricated under different UV exposure times  

NASA Astrophysics Data System (ADS)

An experimental study on hydrofluoric acid (HF)-based clad etching and chemical sensing characteristics of fiber Bragg gratings (FBG) of different reflectivity fabricated under different UV (255 nm) exposure times is presented. Two FBGs of reflectivity 11% and 93% were inscribed by phase mask-based exposition of the photosensitive fibers by a 5.5 kHz repetition rate of 255 nm UV pulses for 15 s and 10 min, respectively. These two FBGs, employed in an HF-based clad etching experiment, revealed a much higher etching rate of 2.03 ?m/min for the grating of reflectivity 11% as compared to 1.69 ?m/min for the grating of reflectivity 93%. The performance of these etched FBGs were also studied for refractive index sensing of the chemicals ethanol and ethylene glycol under different fiber etching times, hence of different residual cladding diameter. It was observed that the same refractive index sensitivity for both the chemicals could be achieved under smaller etching time, i.e., larger residual cladding diameter, for the FBG with lower reflectivity. This differentiating behavior of FBGs under etching and sensing may be linked to the different degree of densification in fused silica fiber cladding under different UV fluence exposures.

Kumar, Jitendra; Mahakud, Ramakant; Prakash, Om; Dixit, Sudhir Kumar

2013-05-01

280

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

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.

Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

2012-01-01

281

Physiological response, time-motion characteristics, and reproducibility of various speed-endurance drills in elite youth soccer players: small-sided games versus generic running.  

PubMed

Purpose: To quantify the physiological responses, time-motion characteristics, and reproducibility of various speed-endurance-production (SEP) and speed-endurance-maintenance (SEM) drills. Methods: Sixteen elite male youth soccer players completed 4 drills: SEP 1 v 1 small-sided game (SSG), SEP running drill, SEM 2 v 2 SSG, and SEM running drill. Heart-rate response, blood lactate concentration, subjective rating of perceived exertion (RPE), and time-motion characteristics were recorded for each drill. Results: The SEP and SEM running drills elicited greater (P < .05) heart-rate responses, blood lactate concentrations, and RPE than the respective SSGs (ES 1.1-1.4 and 1.0-3.2). Players covered less (P < .01) total distance and high-intensity distance in the SEP and SEM SSGs than in the respective running drills (ES 6.0-22.1 and 3.0-18.4). Greater distances (P < .01) were covered in high to maximum acceleration/deceleration bands during the SEP and SEM SSGs than the respective running drills (ES 2.6-4.6 and 2.3-4.8). The SEP SSG and generic running protocols produced greater (P < .05) blood lactate concentrations than the respective SEM protocols (ES 1.2-1.7). Small to moderate test-retest variability was observed for heart-rate response (CV 0.9-1.9%), RPE (CV 2.9-5.7%), and blood lactate concentration (CV 9.9-14.4%); moderate to large test-retest variability was observed for high-intensity-running parameters (CV > 11.3%) and the majority of accelerations/deceleration distances (CV > 9.8%) for each drill. Conclusions: The data demonstrate the potential to tax the anaerobic energy system to different extents using speed-endurance SSGs and that SSGs elicit greater acceleration/deceleration load than generic running drills. PMID:24755972

Ade, Jack D; Harley, Jamie A; Bradley, Paul S

2014-05-01

282

Estimating forest structural characteristics using the airborne LiDAR scanning system and a near-real time profiling laser system  

NASA Astrophysics Data System (ADS)

LiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatially-explicit mapping of forest characteristics, such as canopy height and Leaf Area Index. However, many factors, such as large data volume and high costs for data acquisition, precludes the operational and practical use of most currently available LiDARs for frequent and large-scale mapping. At the same time, a growing need is arising for real-time remote sensing platforms, e.g., to provide timely information for urgent applications. This study aims to develop an airborne profiling LiDAR system, featured with on-the-fly data processing, for near real- or real-time forest inventory. The development of such a system involves implementing the on-board data processing and analysis as well as building useful regression-based models to relate LiDAR measurements with forest biophysical parameters. This work established a paradigm for an on-the-fly airborne profiling LiDAR system to inventory regional forest resources in real- or near real-time. The system was developed based on an existing portable airborne laser system (PALS) that has been previously assembled at NASA by Dr. Ross Nelson. Key issues in automating PALS as an on-the-fly system were addressed, including the design of an archetype for the system workflow, the development of efficient and robust algorithms for automatic data processing and analysis, the development of effective regression models to predict forest biophysical parameters from LiDAR measurements, and the implementation of an integrated software package to incorporate all the above development. This work exploited the untouched potential of airborne laser profilers for real-time forest inventory, and therefore, documented an initial step toward developing airborne-laser-based, on-the-fly, real-time, forest inventory systems. Results from this work demonstrated the utility and effectiveness of airborne scanning or profiling laser systems for remotely measuring various forest structural attributes at a range of scales, i.e., from individual tree, plot, stand and up to regional levels. The system not only provides a regional assessment tool, one that can be used to repeatedly, remotely measure hundreds or thousands of square kilometers with little/no analyst interaction or interpretation, but also serves as a paradigm for future efforts in building more advanced airborne laser systems such as real-time laser scanners.

Zhao, Kaiguang

283

Total Sleep Time and Other Sleep Characteristics Measured by Actigraphy Do Not Predict Incident Hypertension in a Cohort of Community-Dwelling Older Men  

PubMed Central

Study Objective: To evaluate whether actigraphy-measured total sleep time and other sleep characteristics predict incident hypertension in older men. Methods: Study subjects were community-dwelling participants in the ancillary sleep study of the Osteoporotic Fractures in Men Study (MrOS) who were normotensive at the time of actigraphy (based on self-report, lack of antihypertensive medication use, and with systolic blood pressure < 140 mm Hg and diastolic blood pressure < 90 mm Hg). In 853 community-dwelling men 67 years and older (mean 75.1 years), sleep measures (total sleep time [TST]), percent sleep [%-sleep], latency, and wake after sleep onset [WASO]) were obtained using validated wrist actigraphy with data collected over a mean duration of 5.2 consecutive 24-h periods. We evaluated incident hypertension (based on self-report, use of antihypertensive medication, or measured systolic blood pressure ? 140 mm Hg or diastolic blood pressure ? 90 mm Hg) at a follow-up visit an average of 3.4 years later. Baseline prehypertension was defined as a systolic blood pressure 120 to < 140 mm Hg or diastolic blood pressure 80 to < 90 mm Hg. Results: At follow-up, 31% of initially normotensive men were hypertensive (264 of 853). Those with incident hypertension had higher baseline body mass index (BMI; kg/m2) and were more likely to have had prehypertension at the sleep visit than those men who remained normotensive. However, neither TST (reference 6 to < 8 h; < 6 h OR 0.96 [95% CI 0.7, 1.3] and ? 8 h OR 0.93 [0.5, 1.7]) nor the other actigraphic-measured sleep variables, including % -sleep (reference > 85%; < 70% OR 1.17 [0.66, 2.08]) and 70% to ? 85% OR 1.23 (0.9, 1.68), sleep latency (reference < 30 min; ? 30 min OR 1.29 [0.94, 1.76]), or WASO (reference < 30 min; 30 to < 60 min OR 0.7 [0.43, 1.14] and ? 60 min OR 0.92 [0.58, 1.47]) differed in those community-dwelling men who developed incident hypertension compared to those who remained normotensive. Conclusion: TST and other sleep parameters determined by wrist actigraphy were not associated with incident hypertension in community-dwelling older men. Citation: Fung MM; Peters K; Ancoli-Israel S; Redline S; Stone KL; Barrett-Connor E. Total sleep time and other sleep characteristics measured by actigraphy do not predict incident hypertension in a cohort of community-dwelling older men. J Clin Sleep Med 2013;9(6):585-591.

Fung, Maple M.; Peters, Katherine; Ancoli-Israel, Sonia; Redline, Susan; Stone, Katie L.; Barrett-Connor, Elizabeth

2013-01-01

284

Implementation of Near Real-Time Methods Using Surface Waves to Determine Earthquake Source Characteristics at the National Earthquake Information Center  

NASA Astrophysics Data System (ADS)

We discuss the implementation of two near real-time methods for determining earthquake source characteristics using long-period surface waves at the US Geological Survey's National Earthquake Information Center (USGS/NEIC). Long-period (60 to 300 s) seismic waveforms are well suited for this purpose because they can be well modeled using simple propagation models and are less sensitive to source complexity than short period (1 s) waves that are commonly used for earthquake monitoring. A prototype system for Surface wave Location and Association in Quasi Real time (SLAQR) that employs very long period (> 60 s) vertical-component surface waves has been implemented in test mode using data from the Global Seismographic Network (GSN). SLAQR continuously back-projects waveform envelopes on a global grid using surface wave dispersion relations. Preliminary results show that this method, as currently in operation at the NEIC, can consistently locate global earthquakes down to a magnitude 5.5. The magnitude determination, which is based on a simple empirical relationship, is generally accurate to within 0.2 magnitude units. More importantly, SLAQR can provide reliable locations and magnitudes for very large earthquakes, such as the 2004/2005 Sumatra events, within 30-40 minutes of their origin time. Furthermore, since the magnitude calculation is based on long period data, magnitudes for slow earthquakes such as some ridge and tsunami earthquakes are not underestimated as commonly occurs in shorter period analysis. Future development will focus on a reliable triggering algorithm for automated event detection and the continuous calculation of moment tensors and earthquake depths from the spectral amplitude and phase measurements already produced by the system. A fully automatic system to determine centroid moment tensors using three component surface waves with periods between 150-300 s is also running at the NEIC. Two versions are currently operational: one in a research/evaluation mode and another fully incorporated into the NEIC Hydra system. New improvements in the area of reliability assessment are currently being tested. Future work will investigate the finite fault information contained in the centroid time and centroid location parameters, how to incorporate a priori knowledge of the fault orientation, and the use of noise characteristics in the automatic selection of channels.

Polet, J.; Thio, H. K.; Earle, P.

2008-12-01

285

Direct observations in the dusk hours of the characteristics of the storm-time ring current particles during the beginning of magnetic storms  

NASA Technical Reports Server (NTRS)

The characteristic features of the initial enhancement of the storm-time ring current particles in the evening hours are consistent with flow patterns resulting from a combination of inward convection, gradient drift, and corotation which carries plasma sheet protons into low L-values near midnight and the higher energy proton component into the plasmasphere and through the evening hours. Data from four magnetic storms during the early life of Explorer 45, when the local time of apogee was in the afternoon and evening hours, show that protons with lower magnetic moments penetrate deeper into the magnetosphere until a low limit, determined by the corotation and gradient drift forces, is reached. Such particle motions produce the stable energy dependent inner boundary of the ring current protons inside the plasmapause in the dusk sector and also provide the mechanism for energy injection into the ring current region. From the analyses of the pitch angle distributions it is evident that charge exchange and wave particle interactions are not the dominant causes of this inner boundary.

Smith, P. H.; Hoffman, R. A.

1973-01-01

286

Long-term impact of anaerobic reaction time on the performance and granular characteristics of granular denitrifying biological phosphorus removal systems.  

PubMed

Removal of nitrogen and phosphorus (P) from wastewater is successfully and widely practiced in systems employing both granular sludge technology and enhanced biological P removal (EBPR) processes; however, the key parameter, anaerobic reaction time (AnRT), has not been thoroughly investigated. Successful EBPR is highly dependent on an appropriate AnRT, which induces carbon and polyphosphate metabolism by phosphorus accumulating organisms (PAOs). Therefore, the long-term impact of AnRT on denitrifying P removal performance and granular characteristics was investigated in three identical granular sludge sequencing batch reactors with AnRTs of 90 (R1), 120 (R2) and 150 min (R3). The microbial community structures and anaerobic stoichiometric parameters related to various AnRTs were monitored over time. Free nitrite acid (FNA) accumulation (e.g., 0.0008-0.0016 mg HNO2-N/L) occurred frequently owing to incomplete denitrification in the adaptation period, especially in R3, which influenced the anaerobic/anoxic intracellular intermediate metabolites and activities of intracellular enzymes negatively, resulting in lower levels of poly-P and reduced activity of polyphosphate kinase. As a result, the Accumulibacter-PAOs population decreased from 51 ± 2.5% to 43 ± 2.1% when AnRT was extended from 90 to 150 min, leading to decreased denitrifying P removal performance. Additionally, frequent exposure of microorganisms to the FNA accumulation and anaerobic endogenous conditions in excess AnRT cases (e.g., 150 min) stimulated increased extracellular polymeric substances (EPS) production by microorganisms, resulting in enhanced granular formation and larger granules (size of 0.6-1.2 mm), but decreasing anaerobic PHA synthesis and glycogen hydrolysis. Phosphorus removal capacity was mediated to some extent by EPS adsorption in granular sludge systems that possessed more EPS, longer AnRT and relatively higher GAOs. PMID:23863379

Wang, Yayi; Guo, Gang; Wang, Hong; Stephenson, Tom; Guo, Jianhua; Ye, Liu

2013-09-15

287

A multi-model approach to X-ray pulsars. Connecting spectral and timing models to pin down the intrinsic emission characteristics of magnetized, accreting neutron stars  

NASA Astrophysics Data System (ADS)

The emission characteristics of X-ray pulsars are governed by magnetospheric accretion within the Alfvén radius, leading to a direct coupling of accretion column properties and interactions at the magnetosphere. The complexity of the physical processes governing the formation of radiation within the accreted, strongly magnetized plasma has led to several sophisticated theoretical modelling efforts over the last decade, dedicated to either the formation of the broad band continuum, the formation of cyclotron resonance scattering features (CRSFs) or the formation of pulse profiles. While these individual approaches are powerful in themselves, they quickly reach their limits when aiming at a quantitative comparison to observational data. Too many fundamental parameters, describing the formation of the accretion columns and the systems' overall geometry are unconstrained and different models are often based on different fundamental assumptions, while everything is intertwined in the observed, highly phase-dependent spectra and energy-dependent pulse profiles. To name just one example: the (phase variable) line width of the CRSFs is highly dependent on the plasma temperature, the existence of B-field gradients (geometry) and observation angle, parameters which, in turn, drive the continuum radiation and are driven by the overall two-pole geometry for the light bending model respectively. This renders a parallel assessment of all available spectral and timing information by a compatible across-models-approach indispensable. In a collaboration of theoreticians and observers, we have been working on a model unification project over the last years, bringing together theoretical calculations of the Comptonized continuum, Monte Carlo simulations and Radiation Transfer calculations of CRSFs as well as a General Relativity (GR) light bending model for ray tracing of the incident emission pattern from both magnetic poles. The ultimate goal is to implement a unified fitting model for phase-resolved spectral and timing data analysis. We present the current status of this project.

Schönherr, G.; Schwarm, F.; Falkner, S.; Becker, P.; Wilms, J.; Dauser, T.; Wolff, M. T.; Wolfram, K.; West, B.; Pottschmidt, K.; Kretschmar, P.; Ferrigno, C.; Klochkov, D.; Nishimura, O.; Kreykenbohm, I.; Caballero, I.; Staubert, R.

2014-01-01

288

Enhancement Characteristics and Impact on Image Quality of Two Gadolinium Chelates at Equimolar Doses for Time-Resolved 3-Tesla MR-Angiography of the Calf Station  

PubMed Central

Purpose To compare enhancement characteristics and image quality of two macrocyclic gadolinium chelates, gadoterate meglumine and gadobutrol, in low-dose, time-resolved MRA of the calf station. Materials and Methods 100 consecutive patients with peripheral arterial disease (stages II-IV) were retrospectively analysed. Fifty patients were included in each group - 32 men and 18 women for gadobutrol (mean age 67 years) and 34 men, 16 women for gadoterate meglumine (mean age 64 years). 0.03 mmol/kg bw of either gadobutrol or gadoterate meglumine was injected. Gadobutrol was diluted 1?1 with normal saline (0.9% NaCl) to provide similar injection volume and bolus geometry compared to the undiluted 0.5 M dose of gadoterate meglumine. Signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR) and image quality were analysed and compared between the two groups. Results Mean SNR ranged from 83.0±46.7 (peroneal artery) to 96.4±64.5 (anterior tibial artery) for gadobutrol, and from 37.6±13.8 (peroneal artery) to 45.3±16.4 (anterior tibial artery) for the gadoterate meglumine group (p<0.0001). CNR values ranged from 30.1±20.1 (peroneal artery) to 37.6±26.0 (anterior tibial artery) for gadobutrol and from 14.9±8.0 (peroneal artery) to 18.6±16.4 (anterior tibial artery) for gadoterate meglumine (p<0.0001). No significant difference in image quality was found except for the peroneal arteries (p?=?0.006 and p?=?0.04). Interreader agreement was excellent (kappa 0.87–0.93) Conclusion The significantly better enhancement as assessed by SNR and CNR provided by gadobutrol compared to gadoterate meglumine does not translate into substantial differences in image quality in an equimolar, low-dose, time-resolved MRA protocol of the calves.

Hansmann, Jan; Michaely, Henrik J.; Morelli, John N.; Luckscheiter, Andre; Schoenberg, Stefan O.; Attenberger, Ulrike I.

2014-01-01

289

Time-dependent characteristics of the dielectric barrier discharge in Xe-Cl2 mixture and kinetics of the XeCl? molecules  

NASA Astrophysics Data System (ADS)

Time-dependent characteristics of the dielectric barrier discharge in Xe-Cl2 mixture at chlorine concentration of 0.5% and kinetic processes governing the generation of XeCl? molecules are studied using the 1D fluid model. It is shown that at low voltage amplitude (5 kV) a one-peak mode of the discharge is observed and at high voltage amplitude (7 kV) a two-peak mode of the discharge appears. The radiation power of the XeCl? band increases with amplitude of the supply voltage. It is demonstrated that the harpoon reaction Xe? + Cl2 ? XeCl? + Cl provides the greatest contribution into generation of XeCl? exciplex molecules during short current pulses and the ion-ion recombination Xe+ 2 + Cl- ? XeCl* + Xe provides the greatest contribution during afterglow. Quenching of XeCl? molecules is a result of the radiative decay XeCl? ? Xe + Cl + hv (308 nm). During current spike the great contribution into quenching of XeCl? provides also the dissociative ionization e + XeCl? ? Xe+ + Cl + 2e.

Avtaeva, Svetlana

2014-04-01

290

The relationship between biological cognitive and psychosocial characteristics of parents and the weight of infant at the time of birth in Isfahan  

PubMed Central

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 (?=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.

Talebian, Mohammad Hassan; Afrooz, Gholam Ali; Hooman, Heidar Ali; Aghaei, Asghar

2013-01-01

291

Timing matters  

Microsoft Academic Search

Cells are entities in space and time. Systems biology strives to understand their composition, structural organization as well as dynamic behavior under different conditions. Here, measures for dynamic properties such as characteristic times, time hierarchy and time-dependent response are reviewed. Using a number of examples from yeast and micro-organism systems biology, the importance of considering the timing in experimental and

Edda Klipp

2009-01-01

292

Estimating the Timing of Long Bone Fractures: Correlation Between the Postmortem Interval, Bone Moisture Content, and Blunt Force Trauma Fracture Characteristics  

Microsoft Academic Search

There is very limited knowledge about how long perimortem fracture characteristics persist into the postmortem interval (PMI). Therefore, in this study, 60 porcine long bones were exposed to natural taphonomic conditions and fractured with a steel bone breaking apparatus every 28 days throughout a 141-day period. Differences between macroscopic blunt force trauma fracture characteristics (fracture angle, surface mor- phology, and

Danielle A. M. Wieberg; Daniel J. Wescott

2008-01-01

293

The Relationships of the Level of Response to Alcohol and Additional Characteristics to Alcohol Use Disorders across Adulthood: A Discrete-Time Survival Analysis  

PubMed Central

Background A low level of response (LR) to alcohol has been shown to relate to a higher risk for alcohol use disorders (AUDs). However, no previous research has examined the association between LR and the development of AUDs in the context of additional robust risk factors for AUDs. This study evaluated whether LR and other related characteristics predicted the occurrence of AUDs across adulthood using discrete-time survival analysis (DTSA). Methods 297 probands from the San Diego Prospective Study reported on the LR to alcohol, a family history (FH) of AUDs, the typical drinking quantity, the age of drinking onset, the body mass index and the age at the baseline (T1) assessment. Alcohol use disorders (AUDs) were evaluated at the 10-year (T10), T15, T20, and T25 follow-ups. Results A low LR to alcohol predicted AUD occurrence over the course of adulthood even after controlling for the effects of other robust risk factors. Interaction effects revealed that the impact of FH on AUDs was only observed for subjects with high T1 drinking levels, and probands with high T1 drinking were at high risk for AUDs regardless of their age of onset. Conclusion The findings illustrate that LR is a unique risk factor for AUDs across adulthood, and not simply a reflection of a broader range of risk factors. The continued investigation of how LR is related to AUD onset later in life will help inform treatment providers about this high-risk population, and future longitudinal evaluations will utilize DTSA to assess rates of AUD remission as well as the onset of drinking outcomes in adolescent samples.

Trim, Ryan S.; Schuckit, Marc A.; Smith, Tom L.

2010-01-01

294

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)

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.

Leckebusch, G.; Ulbrich, U.; Speth, P.

295

Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts-11-strain M. gallisepticum vaccination on blood characteristics of commercial laying hens.  

PubMed

Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in combination with subsequent time-specific F-strain M. gallisepticum (FMG) inoculations on the blood characteristics of commercial laying hens. The following 4 treatments were utilized: 1) sham vaccination at 10 wk of age, 2) vaccination of ts-11MG at 10 wk, 3) ts-11MG at 10 wk overlaid by FMG inoculation at 22 wk, and 4) ts-11MG at 10 wk overlaid by FMG at 45 wk. Parameters measured in both trials were whole blood hematocrit, plasma protein, serum cholesterol, serum triglycerides, and serum calcium. No significant age x treatment interactions and no significant age or treatment main effects were observed for any of the blood parameters investigated, except for serum calcium. At wk 22, serum calcium concentrations were increased by vaccination with ts-11MG at 10 wk, and levels were further increased when the ts-11MG vaccination at 10 wk was overlaid by an FMG inoculation at 22 wk. These results suggest that ts-11MG vaccination at 10 wk of age alone or combined with F-strain inoculum overlays at either 22 or 45 wk may be used without any consequential effects on hematocrit or the lipid and protein levels in the blood of commercial layers. Because elevations in serum calcium were not associated with changes in hen performance, as reported in a previous companion article, it is further suggested that prelay ts-11MG vaccination before FMG inoculation overlays during lay may provide adequate protection against field strain M. gallisepticum infections while being innocuous to layer performance. PMID:19359676

Peebles, E D; Vance, A M; Branton, S L; Collier, S D; Gerard, P D

2009-05-01

296

Are streamflow recession characteristics characteristic?  

NASA Astrophysics Data System (ADS)

Streamflow recession analysis methods reveal relationships between catchment storage and discharge when precipitation, evapotranspiration, surface storage and groundwater withdrawals are negligible. The falling limb of a hydrograph typically declines over several orders of magnitude and discharge (Q) versus rate of change (-dQ/dt) relationships illustrate a characteristic non-linearity in this storage-outflow dynamic. In the past many different recession analysis methods have been applied in order to quantify the characteristics of this dynamic. Hence there is a need to investigate the influence of the choice of method on recession characteristics. This study assesses a variety of different recession analysis methods to provide information about the reliability and uncertainty of the derived recession characteristics. The different methods can be distinguished by a two-step procedure: first, three different extraction methods select suitable recession segments either with stepwise algorithms from declining hydrographs or supported by precipitation data. The extraction methods lead to a variety of -dQ/dt-Q-plots. Second, the parameters of a commonly used non-linear storage-outflow relationship were estimated from fitting the equation to binned means or to lower envelopes. Finally, the influence of hourly versus daily time step for recession extraction is analyzed. Since each combination of methods may result in different parameters of the non-linear storage-outflow relationships these parameters as well as other characteristic of the derived streamflow recessions like half-life, 30day-low flow or relative storage volume are compared. For 25 meso-scale catchments with different topography and geology in southwest Germany, the observed variability within each catchment was relative large compared to the overall variability among the catchments. In addition, the derived streamflow recession characteristics were not only different due to the methodological approach, but the approaches produced systematically different results with relative low correlation among them for several of the methods. We conclude that different methods to characterize streamflow recessions provide non-unique descriptions of the storage-discharge dynamics and hence make a characterization and also regionalization of these recession characteristics problematic.

Stoelzle, M.; Weiler, M.; Stahl, K.

2012-04-01

297

Correlation of viral load as determined by real-time RT-PCR and clinical characteristics of respiratory syncytial virus lower respiratory tract infections in early infancy  

Microsoft Academic Search

BackgroundIn infants hospitalized for a lower respiratory tract infection (RTI) caused by respiratory syncytial virus (RSV), the correlation between viral load (VL) and patient clinical characteristics remains to be defined.

G. Gerna; G. Campanini; V. Rognoni; A. Marchi; F. Rovida; A. Piralla; E. Percivalle

2008-01-01

298

The geodynamic characteristics of Cretaceous (Paleogene) magmatic belts between the southeastern coast of China and Japan: Implication from ductile deformations time and diagenetic manner  

NASA Astrophysics Data System (ADS)

1.Introduction It is generally believed that the Yanshanian orogeny outlined the present-day geological configuration that has developed since the Jurassic (Li 2000), by which the Early Yanshanian (J3) dominated the Cathaysia interior, whereas the Late Yanshanian (K1) dominated the southeast coastal area. Basically, products of the early Cretaceous magmatism are more restricted in a NE-SW trending zone-the Southeast Coast of China Magmatic Belt (SECMB) in China. Previous investigations have revealed that volcano-intrusive rock assemblages are mainly shallow-level, calc-alkaline, I-type felsic rocks ranging from granodioritic to alkali feldspar granitic, and succeeding A-type granites(Chen et al. 2000). The Cretaceous to Paleogene volcano-intrusive complex rocks are extensively distributed in the WS Japan Magmatic Belt (WSJMB). Note that the majority of granitic intrusions were emplaced in the Cretaceous, and they intruded into the pre-Cretaceous accretionary complexes which include regional metamorphic rocks. The intrusive granitoids are associated with coeval gabbros, diorites, rhyolites and ignimbrites.The formation of the Japanese Islands has been taken as the classic model for accretionary orogeny and often serves as an example for understanding the crustal evolution of the CAOB and other accretionary orogens (Sengor and Natal'in, 1996; Condie, 2007; Cawood and others, 2009). 2. Correlation with two Cretaceous magmatic belts 2.1 The beginning and end times for magmatic activity as well as dynamics deformation time. 2.2 Beginning of high-Mg andesite and adakite produced by melting of subducting oceanic slab in Japan. 2.3 The finishing marks of magmatic activity. 2.4 Approximatively resembling diagenetic manner. 3. Geodynamic characteristics of two magmatic belts The WSJMB is a plutonic-metamorphic terrane that comprises unmetamorphosed pre-Cretaceous accretionary complexes with shallow-level, calc-alkaline, I-type granites-rhyolites, metasediments with migmatites and gneissose granites. The volcano-intrusive complex rocks are dominant over metamorphic rocks, Based on the apparent along-arc variation of isotopic ages, it has been suggested that the Ryoke and Sanyo granitoids were produced by Cretaceous subduction of the Kula-Pacific ridge. Thus, the felsic rocks in WSJMB were formed by partial melting of derived-younger crust all long under subducted compressive setting. Contrarily, the volcano-intrusive complex rocks in SECMB were produced by an immense melting of the Proterozoic crustal material through basaltic underplating, which the upwelled mantle brought up extra heat. As the collision compressive of paleo-Pacific plate during the early Cretaceous (about 125-120Ma) resulted in crustal thickening, succeeding lithospheric delamination or detachment took place, magmas thus were emplaced at extensional environments. The an-orogenic magmatism occured under lithospheric extension-break up environments.

Mao, J.; Takahashi, Y.; Ye, H.; Zhao, X.; Li, Z.; Kee, W.; Liu, K.; Hu, Q.

2011-12-01

299

Effect of Time of Initiation of Feeding after Hatching and Influence of Dietary Ascorbic Acid Supplementation on Productivity, Mortality and Carcass Characteristics of Ross 308 Broiler Chickens in South Africa  

Microsoft Academic Search

An experiment was conducted to evaluate the effect of time of initiation of feeding after hatching and influence of dietary ascorbic supplementation during realimentation on productivity, carcass characteristics and mortality of Ross 308 broiler chickens. The study was a factorial arrangement in a complete randomized design. Six hundred and seventy five unsexed Ross 308 broiler chickens with an initial weight

C. A. Mbajiorgu; D. Norris

2007-01-01

300

Application of time-domain reflectometry (TDR) soil moisture miniprobe for the determination of unsaturated soil water characteristics from undisturbed soil cores  

Microsoft Academic Search

Construction and operating characteristics of a TDR soil moisture miniprobe, that can be inserted through the wall of a metal cylinder, are shown. A laboratory stand for monitoring unsaturated water flow in undisturbed soil cores, involving a set of TDR miniprobes in combination with a set of minitensiometers, is described. This stand was used for frequent readings of instantaneous profiles

M. A. Malicki; R. Plagge; M. Renger; R. T. Walczak

1992-01-01

301

Perception of goal proximity, latency and duration of action plans, and worry in relation to goal distance in time and personality characteristics.  

PubMed

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

Halvari, H

1991-06-01

302

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)

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.

Baumeister, K. J.

1979-01-01

303

Characteristics of nighttime West-to-East VLF waves propagation using the South America VLF Network (SAVNET): Application of the Terminator Time method to Earthquake detection  

NASA Astrophysics Data System (ADS)

We present the monitoring of ~5 years of daily VLF amplitude curves using two parallel propagation paths from the South America VLF Network (SAVNET). During this period, the time of occurrence (Teminator Times) of deep amplitude minima were measured. We discuss typical properties of West-to-East VLF subionospheric propagation like the seasonal effect on the temporal evolution of Terminator Times, the fact that they are simultaneously detected on parallel propagation paths, and the derivation of the undisturbed nighttime ionospheric height. We will also show that he method known as the Terminator Time is also a promising way of looking for possible seismic-electromagnetic effects.

Raulin, Jean Pierre; Samanes Cardenas, Jorge

2012-07-01

304

Maximal force, force\\/time and activation\\/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at different ages  

Microsoft Academic Search

.   This study examined the force production characteristics, activation\\/coactivation and endurance capacity of the neck extension\\u000a and flexion muscles in healthy men (n=29) and women (n=28) divided into three age groups (18–26 years, 30–37 years and 45–55 years). Force and electromyography (EMG) measurements\\u000a were performed during the maximal voluntary isometric extension and flexion actions. This was followed by an endurance test\\u000a (ET; 60%

Heli Valkeinen; Jari Ylinen; Esko Mälkiä; Markku Alen; Keijo Häkkinen

2002-01-01

305

Do socioeconomic characteristics modify the short term association between air pollution and mortality? Evidence from a zonal time series in Hamilton, Canada  

PubMed Central

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.

Jerrett, M; Burnett, R; Brook, J; Kanaroglou, P; Giovis, C; Finkelstein, N; Hutchison, B

2004-01-01

306

Evaluation and Long-Term Monitoring of the Time-Dependent Characteristics of Self-Consolidating Concrete in an Instrumented Kansas Prestressed Concrete Bridge.  

National Technical Information Service (NTIS)

Construction of a new prestressed bridge with Self-Consolidating Concrete (SCC) provided the opportunity to further study the time-dependent properties of SCC mix and its long-term performance; considering the results and recommendations of previous studi...

A. Esmaeily J. Holste R. J. Peterman

2014-01-01

307

Effects of retail style or food service style packaging type and storage time on sensory characteristics of bacon manufactured from commercially sourced pork bellies.  

PubMed

Objectives were to characterize differences in pork bellies that were stored frozen for different durations prior to processing and characterize sensory properties of the bacon derived from those bellies when stored in either retail or food service style packaging. Bellies (n = 102) were collected from 4 different time periods, fresh bellies (never frozen) and bellies frozen for 2, 5, or 7 mo, and manufactured into bacon under commercial conditions. Food service bacon was packaged in oxygen-permeable polyvinyl lined boxes layered on wax-covered lined paper and blast frozen (-33 °C) for 45 or 90 d after slicing. Retail bacon was vacuum-packaged in retail packages and refrigerated (2 °C) in the dark for 60 or 120 d after slicing. At the end of respective storage times after slicing, bacon was analyzed for sensory attributes and lipid oxidation. Off-flavor and oxidized odor of bacon increased (P < 0.01) with increasing storage time in both packaging types. Lipid oxidation increased (P < 0.01) as storage time increased from day 0 to day 45 in food service packaged bacon from frozen bellies, but was unchanged (P ? 0.07) with time in food service packaged bacon from fresh bellies. Lipid oxidation was also unchanged (P ? 0.21) over time in retail packaged bacon, with the exception of bellies frozen for 5 mo, which was increased from day 0 to day 90. Overall, off-flavor, oxidized odor, and lipid oxidation increased as storage time after processing increased. Freezing bellies before processing may exacerbate lipid oxidation as storage time after processing was extended. PMID:24837349

Lowe, B K; Bohrer, B M; Holmer, S F; Boler, D D; Dilger, A C

2014-06-01

308

Characteristics of the m2000 Automated Sample Preparation and Multiplex Real-Time PCR System for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae?  

PubMed Central

We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay.

Marshall, R.; Chernesky, M.; Jang, D.; Hook, E. W.; Cartwright, C. P.; Howell-Adams, B.; Ho, S.; Welk, J.; Lai-Zhang, J.; Brashear, J.; Diedrich, B.; Otis, K.; Webb, E.; Robinson, J.; Yu, H.

2007-01-01

309

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)

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.

Gilroi, H. G.

1979-01-01

310

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)

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).

Trimpi, Robert L.; Cohen, Nathaniel B.

1961-01-01

311

Characteristic time scales of turbulent transport, chemistry, and plant physiology within a tropical rain forest: the exchange of nitrogen oxides and ozone  

NASA Astrophysics Data System (ADS)

The exchange of reactive trace gases at the atmosphere-biosphere interface is the result of several interacting processes including turbulent transport, chemical reactions, and stomatal uptake. This is especially the case in tall tropical forests where turbulent transport plays a key role. By governing the residence time of air within the huge canopy space, transport mechanisms control to what extent emitted and deposited species are affected by these processes during transfer to or from the atmosphere. Within the EUSTACH-LBA project, mean vertical profile and high frequency measurements of wind, temperature, NO, O_3, H_2O, and CO_2 were performed at a tower site in the state of Rondonia (southwest Amazonia), Brazil. Fluxes of heat, O_3, H_2O, and CO_2 were determined by the application of a surface renewal approach on high resolution time series. Good agreement with corresponding fluxes measured by eddy covariance confirmed large scale intermittent turbulent structures to be the dominant exchange mechanisms. A continuous wavelet transform was used to determine the residence times associated with these structures. We compared the results with corresponding time scales of chemical reactions and uptake processes at different canopy levels. Even within a few meters of the forest floor, almost all soil emitted NO reacts with O_3 to form NO_2 due to restricted transport. On the other hand, focusing on O_3 deposition, the chemical reaction with NO plays a minor role compared to the fast uptake process in the uppermost canopy layers.

Rummel, U.; Ammann, C.; Gut, A.; Foken, T.; Andreae, M. O.; Meixner, F. X.

2003-04-01

312

Time series forecast and soil characteristics-based simple and multivariate linear models for management of Diaprepes abbreviatus root weevil in citrus  

Microsoft Academic Search

Synthesis of insect and soil variable patterns in space and time via process models would be useful for reducing the cost of field monitoring and for achieving improved integrated pest management. During 2001–2003, we monitored the Diaprepes abbreviatus (L.) root weevil population in a flatwoods citrus grove containing a sandy Alfisol and a loamy Mollisol in Hendry County, South Florida.

Hong Li; Stephen H. Futch; James P. Syvertsen; Clay W. McCoy

2007-01-01

313

Physico-chemical, textural and structural characteristics of sous-vide cooked pork cheeks as affected by vacuum, cooking temperature, and cooking time.  

PubMed

This paper describes the influence of different factors on sous-vide cooked pork. Pork cheeks were cooked at different combinations of temperature (60°C or 80°C), time (5 or 12h) and vacuum (vacuum or air packaged). Weight losses were lower and moisture content higher in samples cooked for a shorter time (P=0.054) and at a lower temperature (P<0.001). Samples cooked at 60°C showed more lightness (L*) and redness (a*) (P<0.001). Lipid oxidation showed an interaction between cooking time and temperature (P=0.007), with higher TBARs values for samples cooked for 12h at 60°C and lower for those cooked for 12h at 80°C. Samples cooked at 80°C for 12h showed lower (P<0.05) values for most textural parameters than all the other types of samples. Vacuum packaging showed no influence on any of the studied variables. For the treatments evaluated, cooking temperature×time combination seems to be more important than vacuum packaging in the textural and colour parameters of pork cheeks. PMID:22154568

Sánchez Del Pulgar, José; Gázquez, Antonio; Ruiz-Carrascal, Jorge

2012-03-01

314

Wentzel-Kramer-Brillouin and finite-difference time-domain analysis of Terahertz band electromagnetic characteristics of target coated with unmagnetized plasma  

Microsoft Academic Search

We investigate computationally the attenuation and reflection of Terahertz (THz) wave using targets coated with plasmas. The simulators are the Wentzel-Kramer-Brillouin (WKB) method and finite-difference time-domain (FDTD) method. The relation between the frequency of the incident electromagnetic (EM) wave and the attenuation caused by unmagnitized plasma is analyzed. The results demonstrate that the amount of absorbed power is a decreasing

Liu Shaobin; Zhou Tao; Liu Meilin; Hong Wei

2008-01-01

315

Real-time numerical simulations and experimental research for the propagation characteristics of shock waves and gas flow during coal and gas outburst  

Microsoft Academic Search

When coal and gas outburst occurs, high-speed gas flow and air shock wave with high kinetic energy could be created. In this paper, the formation process of outburst shock waves and gas flow has been analyzed firstly. Afterwards, the numerical simulation models of the roadways with right-angled intersection have been established, by which real-time simulation of the propagation of outburst

Kai Wang; Aitao Zhou; Jianfang Zhang; Pin Zhang

316

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)

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.

Nakayama, Y.; Tanaka, S.; Mitsugi, R.

317

Development of a perfusion chamber assay to study in real time the kinetics of thrombosis and the antithrombotic characteristics of antiplatelet drugs  

PubMed Central

Background Arterial thrombosis triggered by vascular injury is a balance between thrombus growth and thrombus fragmentation (dethrombosis). Unbalance towards thrombus growth can lead to vascular occlusion, downstream ischemia and tissue damage. Here we describe the development of a simple methodology that allows for continuous real time monitoring and quantification of both processes during perfusion of human blood under arterial shear rate conditions. Using this methodology, we have studied the effects of antiplatelet agents targeting COX-1 (aspirin), P2Y12 (2-MeSAMP, clopidogrel), GP IIb-IIIa (eptifibatide) and their combinations on the kinetics of thrombosis over time. Results Untreated samples of blood perfused over type III collagen at arterial rates of shear promoted the growth of stable thrombi. Modulation by eptifibatide affected thrombus growth, while that mediated by 2-MeSAMP and aspirin affected thrombus stability. Using this technique, we confirmed the primacy of continuous signaling by the ADP autocrine loop acting on P2Y12 in the maintenance of thrombus stability. Analysis of the kinetics of thrombosis revealed that continuous and prolonged analysis of thrombosis is required to capture the role of platelet signaling pathways in their entirety. Furthermore, studies evaluating the thrombotic profiles of 20 healthy volunteers treated with aspirin, clopidogrel or their combination indicated that while three individuals did not benefits from either aspirin or clopidogrel treatments, all individuals displayed marked destabilization profiles when treated with the combination regimen. Conclusions These results show the utility of a simple perfusion chamber technology to assess in real time the activity of antiplatelet drugs and their combinations. It offers the opportunity to perform pharmacodynamic monitoring of arterial thrombosis in clinical trials and to investigate novel strategies directed at inhibiting thrombus stability in the management of cardiovascular disease.

2012-01-01

318

Effects of preslaughter feed withdrawal time on finishing pig carcass, body weight gain, and food safety characteristics in a commercial environment.  

PubMed

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

Frobose, H L; Dritz, S S; Tokach, M D; Prusa, K J; DeRouchey, J M; Goodband, R D; Nelssen, J L

2014-08-01

319

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)

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).

Ramos, Maria C.

2014-05-01

320

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  

NASA Astrophysics Data System (ADS)

We present 50-210 ?m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 ?m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H2O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 ? 13 up to J = 40 ? 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 ?m [O I] flux ratio is 17.2 ± 9.2. The [O I] 63 ?m line correlates with L 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 bol increased by 1.25 (1.06) and T 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 ({\\langle { {N}}\\rangle} = (0.70 +/- 1.12){{} \\times 10^{49}} total particles). { {N}}_CO correlates strongly with L bol, but neither T rot nor { {N}}_CO(warm)/{ {N}}_CO(hot) correlates with L 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 H2O ({\\langle {T_rot}\\rangle } = 194 +/- 85 K) and OH ({\\langle {T_rot}\\rangle } =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. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Green, Joel D.; Evans, Neal J., II; Jørgensen, Jes K.; Herczeg, Gregory J.; Kristensen, Lars E.; Lee, Jeong-Eun; Dionatos, Odysseas; Yildiz, Umut A.; Salyk, Colette; Meeus, Gwendolyn; Bouwman, Jeroen; Visser, Ruud; Bergin, Edwin A.; van Dishoeck, Ewine F.; Rascati, Michelle R.; Karska, Agata; van Kempen, Tim A.; Dunham, Michael M.; Lindberg, Johan E.; Fedele, Davide; DIGIT Team

2013-06-01

321

Effect of very fast chilling and aging time on ultra-structure and meat quality characteristics of Chinese Yellow cattle M. Longissimus lumborum.  

PubMed

Objectives of the current study were to evaluate meat ultra-structure and tenderness variation at different chilling regimes and aging times. Hot boned longissimus lumborum of 18 Chinese crossbred cattle were divided into 4 portions per side. One portion underwent very fast chilling (VFC, at -21 °C to achieve core temperature of 0 °C, then transferred to another incubator at 2 °C), whereas other treatments were held at 14, 7 and 0 °C for 10 h postmortem, respectively. At 10 h postmortem, all muscles were vacuum aged at 2 °C for 21 d. Cold shortened muscles had greatest absolute amount of tenderization during aging. VFC caused lowest sarcomere length, with super-contractions, ruptured Z-lines and myofibril cleavage, but improved myofibril fragmentation index (MFI), with no significant negative effect on toughness. Overall, aging improved the meat quality of cold shortened beef. Moreover, it should be prudent in some applications to apply VFC to excised muscles from a food safety perspective, and to improve tenderness compared to cold-shortened muscles. PMID:22857853

Li, Ke; Zhang, Yimin; Mao, Yanwei; Cornforth, Daren; Dong, Pengcheng; Wang, Renhuan; Zhu, He; Luo, Xin

2012-12-01

322

Frequency-domain array technique analysis for the rupture duration time and geometrical characteristics of the 2001 Kunlun Mountain Pass earthquake  

NASA Astrophysics Data System (ADS)

In this paper, we briefly describe the principle of tracking energy radiation sources of large earthquakes using frequency-domain far-field array technique, present general steps of tracking energy radiation sources, and take the 2001 Kunlun Mountain Pass earthquake as an example to analyze key factors for setting parameters while processing data. Using broadband waveform data from a seismic array in Ethiopia and Kenya (EK Array), we obtain that the rupture initiation point of the 2001 Kunlun Mountain Pass earthquake is located in the east of Buka Daban Peak (35.92°N, 91.70°E), and the rupture duration time is less than 160 s, the rupture length about 520 km, with 180 km in the west of the initiation point and 340 km in the east, respectively. The western segment of the earthquake fault bends towards southwest near Buka Daban Peak, which is in concordance with the surface rupture trace. The eastern segment apparently bends towards northeast near Xidatan, which is in agreement with the strike of Xidatan fault, but 30 km away from Xidatan fault. In addition, the results imply that the western segment of the earthquake fault appears erect while the eastern segment appears to be gradually dipping southwards.

Zhang, Hong-Xia; Xu, Li-Sheng; Chen, Yun-Tai; Li, Chun-Lai; Klaus, Stammler

2008-01-01

323

Are streamflow recession characteristics really characteristic?  

NASA Astrophysics Data System (ADS)

Streamflow recession has been investigated by a variety of methods, often involving the fit of a model to empirical recession plots to parameterize a non-linear storage-outflow relationship. Such recession analysis methods (RAMs) are used to estimate hydraulic conductivity, storage capacity, or aquifer thickness and to model streamflow recession curves for regionalization and prediction at the catchment scale. Numerous RAMs have been published, but little is known about how characteristic the resulting recession models are to distinguish characteristic catchment behavior. In this study we combined three established recession extraction methods with three different parameter-fitting methods to the power-law storage-outflow model to compare the range of recession characteristics that result from the application of these different RAMs. Resulting recession characteristics including recession time and corresponding storage depletion were evaluated for 20 meso-scale catchments in Germany. We found plausible ranges for model parameterization, however, calculated recession characteristics varied over two orders of magnitude. While recession characteristics of the 20 catchments derived with the different methods correlate strongly, particularly for the RAMs that use the same extraction method and while they rank the catchments relatively consistent, there are still considerable differences among the methods. To elucidate this variability we discuss the ambiguous roles of recession extraction procedures and the parameterization of storage-outflow model and the limitations of the presented recession plots. The results suggest strong limitations to the comparability of recession characteristics derived with different methods, not only in the model parameters but also in the relative characterization of different catchments. A multiple methods approach to investigate streamflow recession characteristics should be considered for applications whenever possible.

Stoelzle, M.; Stahl, K.; Weiler, M.

2012-09-01

324

Characteristics of climate and environmental signals with the various time scales from past 720,000 years in Dome Fuji ice core, Antarctica  

NASA Astrophysics Data System (ADS)

Two deep ice cores (DF1: 2503m and DF2: 3035m) at Dome Fuji, Antarctica have the in-depth information of global environmental change from present to the past 720,000 years. We made the data set of major ion concentration, dust concentration and stable isotope ratio which were analyzed 10cm sample every 50cm from 2400m to 3035m using the DF2 core. The age of this depth was covered from 300,000 to 720,000 years before. Using the DF1 core, major chemical species were carried out using 7-10cm ice samples cut out of the 50 cm-long spaced from 0.5 to 2.5m. All data was averaged by every 5 m or every 1,000 years. The indexes of climate and environment are the following elements; MSA-, Cl-, NO3-, SO42-, H+ (calculated from pH), Na+, NH4+, K+, Mg2+, Ca2+, ss-Na+, nss-Cl-, nss-SO42-, nss-K+, nss-Mg2+, nss-Ca2+, dD, d18O, d-excess, dust, pH and electrical conductivity. There is a feature in correlation respectively by the climatic stage. dD or d18O which becomes the index of the temperature and the environmental elements (for example, Na+ and Mg2+) indicate the strong negative correlation, but its degree is different depending on the climatic stages. Deep ice core records are compared with initial conditions (precipitation and surface snow). Time scales of our studies are daily, yearly, millennial-scales and glacial-interglacial cycle. We show the difference of the chemistry of surface snow by the difference of the snow type in the same area.

Motoyama, Hideaki; Fuji ice core project members, Dome

2013-04-01

325

Changes in isometric force- and relaxation-time, electromyographic and muscle fibre characteristics of human skeletal muscle during strength training and detraining.  

PubMed

Eleven male subjects (20-32 years) accustomed to strength training went through progressive, high-load strength training for 24 weeks with intensities ranging variably between 70 and 120% during each month. This training was also followed by a 12-week detraining period. An increase of 26.8% (P less than 0.001) in maximal isometric strength took place during the training. The increase in strength correlated (P less than 0.05) with significant (P less than 0.05-0.01) increases in the neural activation (IEMG) of the leg extensor muscles during the most intensive training months. During the lower-intensity training, maximum IEMG decreased (P less than 0.05). Enlargements of muscle-fibre areas, especially of fast-twitch type (P less than 0.001), took place during the first 12 weeks of training. No hypertrophic changes were noted during the latter half of training. After initial improvements (P less than 0.05) no changes or even slight worsening were noted in selected force-time parameters during later strength training. During detraining a great (P less than 0.01) decrease in maximal strength was correlated (P less than 0.05) with the decrease (P less than 0.05) in the maximum IEMGs of the leg extensors. This period resulted also in decreases (P less than 0.05) of the mean muscle-fibre areas of both fibre types. It was concluded that improvement in strength may be accounted for by neural factors during the course of very intensive strength training. Selective training-induced hypertrophy also contributed to strength development but muscle hypertrophy may have some limitations during long-lasting strength training, especially in highly trained subjects. PMID:4091001

Häkkinen, K; Alén, M; Komi, P V

1985-12-01

326

Patient characteristics that influence efficacy of prophylaxis with rFVIII-FS three times per week: a subgroup analysis of the LIPLONG study.  

PubMed

Prospective data on the efficacy of secondary prophylaxis in adults with haemophilia A are limited. To analyse bleeding outcomes in the sucrose-formulated recombinant factor VIII [rFVIII-FS (control)] arm of the LIPLONG study, a randomized, double-blind, 52-week trial was conducted in patients with severe haemophilia A receiving prophylaxis with the investigational product BAY 79-4980 or rFVIII-FS. The per-protocol population of previously treated patients with severe haemophilia A without a history of inhibitors (n = 68 males; mean age, 34.4 years) received 25 IU kg?1 rFVIII-FS three times per week for a median of 50.7 weeks. Annualized bleeding rates were assessed and analysed according to predefined target joint status at study start, prestudy treatment type (prophylaxis vs. on demand), age (<30 or ?30 years), geographical region, bleeding frequency during the previous 6 months and physical activity status during the study using the Student t-test. The annualized median (range) number of bleeds was 2.2 (0.0–23) bleeds per year. The median (range) number of bleeds per year was significantly lower in patient subgroups without vs. with target joints [0.5 (0.0–17.1) vs. 4.2 (0.0–22.8); P = 0.02] and in those with ?9 vs. >9 bleeds during the previous 6 months [1.1 (0.0–19.2) vs. 5.3 (0.0–22.8); P = 0.01]. Following randomization to prophylaxis with rFVIII-FS, bleeding frequency was effectively reduced. Absence of target joints and prestudy bleeding frequency were predictors of a low bleeding frequency during prophylaxis treatment. PMID:24847524

Lalezari, S; Coppola, A; Lin, J; Enriquez, M M; Tseneklidou-Stoeter, D; Powell, J; Ingerslev, J

2014-05-01

327

Are streamflow recession characteristics really characteristic?  

NASA Astrophysics Data System (ADS)

Streamflow recession has been investigated by a variety of methods, often involving the fit of a model to empirical recession plots to parameterize a non-linear storage-outflow relationship based on the dQ/dt-Q method. Such recession analysis methods (RAMs) are used to estimate hydraulic conductivity, storage capacity, or aquifer thickness and to model streamflow recession curves for regionalization and prediction at the catchment scale. Numerous RAMs have been published, but little is known about how comparably the resulting recession models distinguish characteristic catchment behavior. In this study we combined three established recession extraction methods with three different parameter-fitting methods to the power-law storage-outflow model to compare the range of recession characteristics that result from the application of these different RAMs. Resulting recession characteristics including recession time and corresponding storage depletion were evaluated for 20 meso-scale catchments in Germany. We found plausible ranges for model parameterization; however, calculated recession characteristics varied over two orders of magnitude. While recession characteristics of the 20 catchments derived with the different methods correlate strongly, particularly for the RAMs that use the same extraction method, not all rank the catchments consistently, and the differences among some of the methods are larger than among the catchments. To elucidate this variability we discuss the ambiguous roles of recession extraction procedures and the parameterization of the storage-outflow model and the limitations of the presented recession plots. The results suggest strong limitations to the comparability of recession characteristics derived with different methods, not only in the model parameters but also in the relative characterization of different catchments. A multiple-methods approach to investigating streamflow recession characteristics should be considered for applications whenever possible.

Stoelzle, M.; Stahl, K.; Weiler, M.

2013-02-01

328

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

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.

2011-01-01

329

Time characteristics of laser initiation of PETN  

Microsoft Academic Search

Conclusions  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a We have investigated the dependence of the initiation-energy threshold for PETN on the length of the initiating laser pulse\\u000a (?=1.06 ?) over the interval 7.5–100 nsec for both direct photo-initiation of the charge and indirect initiation by means\\u000a of an intervening metal film (300 ). In these two cases the initiation-energy threshold increases with pulse length by factors

A. A. Volkova; A. D. Zinchenko; I. V. Sanin; V. I. Tarzhanov; B. B. Tokarev

1977-01-01

330

Characteristics of pressure waves  

NASA Technical Reports Server (NTRS)

Air blast characteristics generated by most types of explosions are discussed. Data cover both negative and positive blast load phases and net transverse pressure as a function of time. The effects of partial or total confinement, atmospheric propagation, absorption of energy by ground shock or cratering, and transmission over irregular terrain on blast wave properties were also considered.

1977-01-01

331

Decay time characteristics of La2O2S:Eu and La2O2S:Tb for use within an optical sensor for human skin temperature measurement  

SciTech Connect

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.

Yap, Sook Voon; Ranson, Robert M.; Cranton, Wayne M.; Koutsogeorgis, Demosthenes

2008-09-20

332

Disability Characteristics  

MedlinePLUS

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333

Geologic Time  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses the characteristics of geologic time, including the law of superposition, fossil preservation, casts and molds, and various events through the history of the Earth. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

334

Water characteristics  

SciTech Connect

Recent research on water characteristics is cited in this review article. Acid precipitation has been noted as one of the major environmental problems of the current decade. It poses a serious challenge to national and international bodies to protect water quality. Considerable interest was voiced in 1980 over the causes and effects, prevention and control of acid rain. One study estimated that acid rain was causing an estimated annual $5 billion loss in crop, forest, and aquatic yields. Several conferences were held during 1980 on acid rain problems. Groundwater contamination from acid rain was cited as one of the many current and anticipated problems in maintaining a clean and healthful water supply. Acid rain and vegetation interactions were studied in depth, as were the effects of acid precipitation on aquatic organisms. A procedure was developed which may be useful in the quantification of acid rain via isolated precipitation events. Acid precipitation was studied in forest environments. Two efforts assessed the potential for acid rain to leach into the soil. 154 references.

Smith, E.D.

1981-06-01

335

Experimental and theoretical investigation of boundary layer perturbations on a low-aspect-ratio wing  

NASA Astrophysics Data System (ADS)

Laminar-turbulent transition in a boundary layer of low-aspect-ratio wing was investigated. Experiments clarifying the flow structure, its mean and oscillatory characteristics were carried out accompanied by linear stability analysis of the wind tunnel data on the laminar flow velocity profiles. Theoretical results obtained in a parallel flow approximation are in a good agreement with the experimental data on disturbances evolution at the initial stage of transition to turbulence.

Kozlov, V. V.; Zverkov, I. D.; Zanin, B. Yu.; Dovgal, A. V.; Rudyak, V. Ya.; Bord, E. G.; Kranchev, D. F.

2006-12-01

336

Time After Time  

NSDL National Science Digital Library

Students use a variety of strategies and techniques to develop an understanding of telling time. They use estimation to tell time, using seconds, hours, and minutes in order to choose reasonable time estimates for given activities. Students use pictures, words, and symbols in order to read, write, and represent time to the nearest minute. Students determine elapsed time when given a start time, counting up using minutes and hours.

Service, National S.

2009-04-22

337

U-Pb dating, Hf-isotope characteristics and trace-REE-patterns of zircons from Medet porphyry copper deposit, Bulgaria: implications for timing, duration and sources of ore-bearing magmatism  

NASA Astrophysics Data System (ADS)

Precise U-Pb geochronology, Hf isotope compositions and trace element distributions in zircons are combined in the present study to define the timing and sources of the magmatism forming the Medet porphyry copper deposit, Bulgaria. ID-TIMS U-Pb-zircon dating demonstrates that ore-bearing magmatism extended for less than 1.12 Ma. As inferred from the field relationships, it started with the intrusion of a quartz-monzodiorite at 90.59 ± 0.29 Ma followed by granodiorite porphyries at 90.47 ± 0.30 and 90.27 ± 0.60 Ma and by crosscutting aplite dykes at 90.12 ± 0.36 Ma. These units were overprinted by potassic alteration and host economic copper-(Mo-Au) mineralization. The main magmatic-hydrothermal activity ceased after that, and a later quartz-granodiorite porphyry dyke, dated at 89.26 ± 0.32 Ma, only contains an uneconomic quartz-pyrite mineralization. Assimilation of Lower Paleozoic rocks with a mantle to mantle-crust signature is characteristic of the fertile magma in the Medet deposit, as defined by positive ?-Hf values of the inherited zircons. The positive Ce-anomalies and the higher Eu/Eu* ratios of the zircons in the mineralized Cretaceous rocks of Medet deposit argue for crystallization from a generally more oxidized magma compared to the later quartz-granodiorite porphyry dyke. A change in paleostress conditions occurred during the intrusion of the Medet pluton and its dykes. The initial stage reveals E-W extension associated with N-S compression, whereas the younger granodiorite dyke was emplaced during subsequent N-S extension. The large-scale switch of the extensional stress regime during the mineralization was favourable for ore deposition by channelling the fluids and increasing the effective permeability.

Peytcheva, Irena; von Quadt, Albrecht; Neubauer, Franz; Frank, Martin; Nedialkov, Rossen; Heinrich, Christoph; Strashimirov, Strashimir

2009-05-01

338

Timing Apparatuur (Timing Apparatus).  

National Technical Information Service (NTIS)

The apparatus required for bundle-synchronous timing is described. Bundle-synchronous timing signals are used along accelerators and in experimental stations. The apparatus consists of a trigger modulator, a trigger detector, a delayed pulse generator, an...

P. Timmer

1985-01-01

339

ILLIAC 4 systems characteristics and programming manual  

NASA Technical Reports Server (NTRS)

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.

1973-01-01

340

Three-dimensional modeling of diesel engine intake flow, combustion and emissions  

NASA Technical Reports Server (NTRS)

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.

Reitz, R. D.; Rutland, C. J.

1992-01-01

341

Demand Management Demonstration Project. Stage 1: Development of Residential Load Characteristics and Stage 4: Demonstration of Residential Incremental Cost Pricing Implemented by Time-of-Day Metering. Final Report, January 1979.  

National Technical Information Service (NTIS)

In March of 1975 The Ohio Public Utilities Commission entered into a cooperative agreeement with the Federal Energy Administration to conduct a Demand Management Demonstration Project involving a Residential Load Survey, Time-of-Day Pricing, Radio-Control...

1979-01-01

342

Time of Time  

NASA Astrophysics Data System (ADS)

In his landmark 1977 paper "The Temporal Logic of Programs", Amir Pnueli gave a fundamental recognition that the ideally nonterminating behavior of ongoing concurrent programs, such as operating systems and protocols, was a vital aspect of program reasoning. As classical approaches to program correctness were based on initial-state/final-state semantics for terminating programs, these approaches were inapplicable to programs where infinite behavior was the norm. To address this shortcoming, Pnueli suggested the use of temporal logic, a formalism for reasoning about change over time originally studied by philosophers, to meaningfully describe and reason about the infinite behavior of programs. This suggestion turned out to be remarkably fruitful. It struck a resonant chord within the formal verification community, and it has had an enormous impact on the development of the area. It matured into an extremely effective mathematical tool for specifying and verifying a vast class of synchronization and coordination problems common in concurrency. Pnueli thus caused a sea-change in the field of program verification, founding the time of reasoning about time, which has been the most successful period in formal methods yet.

Allen Emerson, E.

343

How Reaction Time, Update Time, and Adaptation Time Influence the Stability of Traffic Flow  

Microsoft Academic Search

When modeling the acceleration and decel- eration of drivers, there are three characteristic time con- stants that influence the dynamics and stability of traffic flow: The reaction time of the drivers, the velocity adap- tation time needed to accelerate to a new desired velocity, and the numerical update time. By means of numerical simulations with a time-continuous car-following model, we

Arne Kesting; Martin Treiber

2008-01-01

344

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

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.

Soldati, Nicola; Calhoun, Vince D.; Bruzzone, Lorenzo; Jovicich, Jorge

2013-01-01

345

Telling Time  

NSDL National Science Digital Library

Practice telling time with these fun games and activities! Match the time on the clocks with this game! Match the clocks game! Primary Games Match the Clocks Tell time with a dragon. Stop the clock! Make the right time! Time to the Hour Quiz Time Test Time to the Minute Quiz Practice telling what time it will be later. Elapsed Time Work on Elapsed Time Test your skills with the Matching Elapsed Time Game ...

Lerdahl, Miss

2010-01-26

346

Thermistor Characteristics and Stability.  

ERIC Educational Resources Information Center

Discusses the uses of thermistors in teaching electronics and semiconductors. Describes how to experimentally measure and graph the characteristics of a thermistor. Suggests one possible approach to understand the shapes of the characteristics. (CW)

Fricker, H. S.

1987-01-01

347

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...

348

An assessment on seasonal analysis of wind energy characteristics and wind turbine characteristics  

Microsoft Academic Search

This paper presents seasonal variations of the wind characteristics and wind turbine characteristics in the regions around Elazig, namely Maden, Agin and Keban. Mean wind speed data in measured hourly time series format is statistically analyzed for the six year period 1998–2003. The probability density distributions are derived from the time series data and their distributional parameters are identified. Two

E. Kavak Akpinar; S. Akpinar

2005-01-01

349

Telling Time  

NSDL National Science Digital Library

Practice telling time with these fun games and activities! Match the time on the clocks with this game! Match the clocks game! Tell time with a dragon. Stop the clock! Practice telling what time it will be later. Elapsed Time ...

Fiefia, Mrs.

2010-03-23

350

A real-time semi-quantitative RT-PCR assay demonstrates that the pilE sequence dictates the frequency and characteristics of pilin antigenic variation in Neisseria gonorrhoeae  

Microsoft Academic Search

A semi-quantitative real-time RT-PCR assay was designed to measure gonococcal pilin antigenic- variation (SQ-PCR Av assay). This assay employs 17 hybridization probe sets that quantitate sub- populations of pilin transcripts carrying different silent pilin copy sequences and one set that detects total pilE transcript levels. Mixtures of a DNA stan- dard carrying the silent copy being detected and a clone

Melissa S. Rohrer; Matthew P. Lazio; H. Steven Seifert

2005-01-01

351

Structural and Environmental Characteristics of Stereotyped Behaviors.  

ERIC Educational Resources Information Center

This study examined structural characteristics and environmental variables in the stereotypic behaviors of eight individuals with developmental disabilities. Findings indicated that structural characteristics (percentage of time, bout length, and bout length variability) were highly correlated. Also, stereotyped behaviors were more likely to occur…

Hall, Scott; Thorns, Tracy; Oliver, Chris

2003-01-01

352

Adjoint operator approach in marginal separation theory  

NASA Astrophysics Data System (ADS)

Thin airfoils are prone to localized flow separation at their leading edge if subjected to moderate angles of attack ?. Although 'laminar separation bubbles' at first do not significantly alter the airfoil performance, they tend to 'burst' if a is increased further or perturbations acting upon the flow reach a certain intensity. This then leads either to global flow separation (stall) or triggers the laminar-turbulent transition process within the boundary layer flow. The present paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number Re --> ?, commonly referred to as marginal separation theory (MST). A new approach based on the adjoint operator method is presented to derive the fundamental similarity laws of MST and to extend the analysis to higher order. Special emphasis is placed on the breakdown of the flow description, i.e. the formation of finite time singularities (a manifestation of the bursting process), and its resolution based on asymptotic reasoning. The computation of the spatio-temporal evolution of the flow in the subsequent triple deck stage is performed by means of a Chebyshev spectral method. The associated numerical treatment of fractional integrals characteristic of MST is based on barycentric Lagrange interpolation, which is described in detail.

Braun, Stefan; Scheichl, Stefan; Kluwick, Alfred

2013-10-01

353

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.  

PubMed

Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) 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 commercial egg-laying hens. In each trial, the following 4 treatments were utilized: sham vaccination at 10 wk of age, ts-11MG vaccination at 10 wk of age, ts-11MG at 10 wk of age overlaid by FMG inoculation at 22 wk of age, and ts-11MG at 10 wk of age overlaid by FMG at 45 wk of age. Necropsies were performed at the end of both trials (58 wk of age), using 2 birds from each of 4 replicate units per treatment, to observe treatment effects on the following parameters: liver weight, liver lipid and moisture concentrations, incidence of fatty liver hemorrhagic syndrome, ovary weight, number of mature ovarian follicles, and the total and segmental weights, lengths, and histologies of the oviduct and small intestine. Treatments affected only vaginal length as a percentage of total oviduct length. Vaginas were relatively longer in hens that had only been vaccinated with ts-11MG at 10 wk in comparison to all the other treatment groups, including controls. Except for relative vaginal length, the digestive and reproductive organs of layers were not influenced by the ts-11MG and FMG treatment regimens imposed in this study. These results confirm that when coupled with FMG inoculations during lay, prelay ts-11MG vaccinations may be a practical substitute for prelay FMG inoculations for providing continual protection against field-strain M. gallisepticum infections in layers. PMID:19359686

Vance, A M; Branton, S L; Collier, S D; Gerard, P D; Peebles, E D

2009-05-01

354

Viscoelastic and aging characteristics of polymers  

SciTech Connect

This paper concerns the time dependent mechanical properties for incompressible polymer-like materials subjected to finite deformations. There are two parts: the viscoelastic effects and the aging characteristics. A method for determining these mechanical properties is presented in detail.

Feng, W W

1984-04-01

355

Effects of prelay ts11-strain Mycoplasma gallisepticum inoculation and time-specific F-Strain M. gallisepticum inoculation overlays on internal egg and eggshell characteristics of commercial laying hens.  

PubMed

Mycoplasma infections are pandemic in multiage layer chicken flocks, with Mycoplasma gallisepticum being the species of greatest concern to commercial egg producers. Live M. gallisepticum vaccines are presently being used to help control M. gallisepticum outbreaks. However, vaccination of layers with F-strain M. gallisepticum may adversely affect egg production. In the present study, 2 trials were conducted to compare the effects of 2 currently available live Mycoplasma vaccines (the ts11- and F-strains), used in conjunction, on internal egg and eggshell characteristics. The following 4 inoculation treatments were used: 1) sham at 10 wk of age (control), 2) ts11 at 10 wk, 3) ts11 at 10 wk overlaid by F at 22 wk, and 4) ts11 at 10 wk overlaid by F at 45 wk. In each trial at various ages between 23 and 57 wk of age, percentage of yolk weight, percentage of yolk moisture, percentage of yolk lipid, percentage of albumen weight, Haugh unit scores, and percentage of shell weight of eggs were assessed. At wk 32, percentage of yolk lipid was increased in eggs belonging to the ts11 at 10 wk and ts11 at 10 wk overlaid by F at 22 wk treatment groups in comparison with controls. There was also a significant decrease in percentage of albumen weight in eggs in the treatment with ts11 at 10 wk overlaid by F at 22 wk, as well as a decrease in Haugh unit scores in the ts11 at 10 wk treatment in comparison with controls during post-peak lay. Percentage of yolk moisture, percentage of egg yolk weight, and percentage of eggshell weight in layers were not significantly affected by a 10-wk ts11 inoculation alone or in conjunction with subsequent overlay inoculations of F during lay. It is suggested that a 10-wk inoculation of commercial layers with ts11-strain M. gallisepticum may reduce the negative impacts of a prelay F-strain M. gallisepticum inoculation on performance while providing protection against subsequent field strain M. gallisepticum infections. PMID:18577616

Vance, A M; Branton, S L; Collier, S D; Gerard, P D; Peebles, E D

2008-07-01

356

MR characteristics of iophendylate (Pantopaque).  

PubMed

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

Hackney, D B; Grossman, R I; Zimmerman, R A; Joseph, P M; Goldberg, H I; Bilaniuk, L T

1986-01-01

357

Electrical interface characteristics (I-V), optical time of flight measurements, and the x-ray (20 keV) signal response of amorphous-selenium/crystalline-silicon heterojunction structures  

NASA Astrophysics Data System (ADS)

We have investigated the dark current, optical TOF (time of flight) properties, and the X-ray response of amorphousselenium (a-Se)/crystalline-silicon (c-Si) heterostructures for application in digital radiography. The structures have been studied to determine if an x-ray generated electron signal, created in an a-Se layer, could be directly transferred to a c-Si based readout device such as a back-thinned CCD (charge coupled device). A simple first order band-theory of the structure indicates that x-ray generated electrons should transfer from the a-Se to the c-Si, while hole transfer from p-doped c-Si to the a-Se should be blocked, permitting a low dark signal as required. The structures we have tested have a thin metal bias electrode on the x-ray facing side of the a-Se which is deposited on the c-Si substrate. The heterostructures made with pure a-Se deposited on epitaxial p-doped (5×10 14 cm-3) c-Si exhibited very low dark current of 15 pA cm-2 at a negative bias field of 10 V ?m-1 applied to the a-Se. The optical TOF (time of flight) measurements show that the applied bias drops almost entirely across the a-Se layer and that the a-Se hole and electron mobilities are within the range of commonly accepted values. The x-ray signal measurements demonstrate the structure has the expected x-ray quantum efficiency. We have made a back-thinned CCD coated with a-Se and although most areas of the device show a poor x-ray response, it does contain small regions which do work properly with the expected x-ray sensitivity. Improved understanding of the a-Se/c-Si interface and preparation methods should lead to properly functioning devices.

Hunter, David M.; Ho, Chu An; Belev, George; de Crescenzo, Giovanni; Kasap, Safa O.; Yaffe, Martin J.

2011-03-01

358

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)

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.

Jacques, Dominique; Muchez, Philippe; Sintubin, Manuel

2014-05-01

359

Continuous time random walk, Mittag-Leffler waiting time and fractional diffusion: mathematical aspects  

Microsoft Academic Search

We show the asymptotic long-time equivalence of a generic power law waiting time distribution to the Mittag-Leffler waiting time distribution, characteristic for a time fractional CTRW. This asymptotic equivalence is effected by a combination of \\

Rudolf Gorenflo; Francesco Mainardi

2007-01-01

360

Correlating Aluminum Burning Times  

Microsoft Academic Search

Characteristics of aluminum combustion are summarized in an overview of the subject, focusing on the burning time of individual particles. Combustion data from over ten different sources with almost 400 datum points have been cataloged and correlated. Available models have also been used to evaluate combustion trends with key environmental parameters. The fundamental concepts that control aluminum combustion are discussed,

M. W. Beckstead

2005-01-01

361

Characteristics of early psychosis  

Microsoft Academic Search

There is little research on characteristics related to course and prognosis of early-onset psychosis. The present article aims to advance our knowledge of this disorder for the purpose of proper diagnosis and treatment. It focuses on premorbid and prodromal characteristics, treatment history, symptoms and classifications, and differences between subgroups with affective and schizophrenic psychosis.A chart review was constructed to study

Patricia F. Schothorst; Claudia Emck; Herman van Engeland

2006-01-01

362

Characteristics of Successful Schools.  

ERIC Educational Resources Information Center

The Department of Public Instruction is actively involved in efforts to improve the school experience and educational outcomes in Wisconsin. Chapter 1, "What Are the Characteristics of Successful Schools?" examines the seven characteristics of successful schools, which describe the school environment, goals, and management strategies and allow all…

Wisconsin State Dept. of Public Instruction, Madison.

363

Characteristics of Successful Entrepreneurs.  

ERIC Educational Resources Information Center

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,…

McClelland, David C.

1987-01-01

364

Universal Time  

NSDL National Science Digital Library

This article explains the concept of 'Universal Time' (UT), sometimes referred to as 'Coordinated Universal Time' (UTC). Topics include how UTC is measured, who uses it, and a brief discussion of the historical context of this time standard.

365

Comparison of Intercooler Characteristics  

NASA Technical Reports Server (NTRS)

A method is presented of comparing the performance, weight, and general dimensional characteristics of inter-coolers. The performance and dimensional characteristics covered in the comparisons are cooling effectiveness, pressure drops and weight flows of the charge and cooling air, power losses, volume, frontal area, and width. A method of presenting intercooler data is described in which two types of charts are plotted; (1) A performance chart setting forth all the important characteristics of a given intercooler and (2) a replot of these characteristics for a number of intercoolers intended to assist in making a selection to satisfy a given set of installation conditions. The characteristics of commercial intercoolers obtained from manufacturers' data and of some computed designs are presented on this basis. A standard test procedure and instrumentation are suggested whereby comparable data may be obtained by different testing organizations.

Reuter, J. George; Valerino, Michael F.

1941-01-01

366

On recent developments in marginal separation theory.  

PubMed

Thin aerofoils are prone to localized flow separation at their leading edge if subjected to moderate angles of attack ?. Although 'laminar separation bubbles' at first do not significantly alter the aerofoil performance, they tend to 'burst' if ? is increased further or if perturbations acting upon the flow reach a certain intensity. This then either leads to global flow separation (stall) or triggers the laminar-turbulent transition process within the boundary layer flow. This paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number [Formula: see text], commonly referred to as marginal separation theory. A new approach based on the adjoint operator method is presented that enables the fundamental similarity laws of marginal separation theory to be derived and the analysis to be extended to higher order. Special emphasis is placed on the breakdown of the flow description, i.e. the formation of finite-time singularities (a manifestation of the bursting process), and on its resolution being based on asymptotic arguments. The passage to the subsequent triple-deck stage is described in detail, which is a prerequisite for carrying out a future numerical treatment of this stage in a proper way. Moreover, a composite asymptotic model is developed in order for the inherent ill-posedness of the Cauchy problems associated with the current flow description to be resolved. PMID:24936013

Braun, S; Scheichl, S

2014-07-28

367

On recent developments in marginal separation theory  

PubMed Central

Thin aerofoils are prone to localized flow separation at their leading edge if subjected to moderate angles of attack ?. Although ‘laminar separation bubbles’ at first do not significantly alter the aerofoil performance, they tend to ‘burst’ if ? is increased further or if perturbations acting upon the flow reach a certain intensity. This then either leads to global flow separation (stall) or triggers the laminar–turbulent transition process within the boundary layer flow. This paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number , commonly referred to as marginal separation theory. A new approach based on the adjoint operator method is presented that enables the fundamental similarity laws of marginal separation theory to be derived and the analysis to be extended to higher order. Special emphasis is placed on the breakdown of the flow description, i.e. the formation of finite-time singularities (a manifestation of the bursting process), and on its resolution being based on asymptotic arguments. The passage to the subsequent triple-deck stage is described in detail, which is a prerequisite for carrying out a future numerical treatment of this stage in a proper way. Moreover, a composite asymptotic model is developed in order for the inherent ill-posedness of the Cauchy problems associated with the current flow description to be resolved.

Braun, S.; Scheichl, S.

2014-01-01

368

Flowfield-Dependent Mixed Explicit-Implicit (FDMEL) Algorithm for Computational Fluid Dynamics  

NASA Technical Reports Server (NTRS)

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.

Garcia, S. M.; Chung, T. J.

1997-01-01

369

Vibration Characteristics of Thermoplastic Composite  

NASA Astrophysics Data System (ADS)

Unreinforced, Long fiber and Short fiber polypropylene composites are being used in many antivibration applications, due to their time and temperature dependent specific mechanical properties. Their good damping behavior accounts for many engineering applications. For utilization of these materials in specific engineering applications, there is a need to understand the damping behavior of composites under dynamic load. For this work, unreinforced and 20% long and short reinforced glass fiber polypropylene composite materials were tested for forced transverse vibration damping characteristics under static as well as fatigue loading conditions. The damping characteristics are quantified by forced frequency response of the test material. Presence of reinforced fibers increases the damping capacity. Among reinforcements, short fiber reinforced polypropylene shows increased damping capacity then long glass fiber reinforced.

Haldar, Amit Kumar; Singh, Satnam; Prince, Prince

2011-12-01

370

Physical Characteristics of Places: The Fossil Record  

NSDL National Science Digital Library

This lesson asks students to consider how the movement of tectonic plates alters the physical characteristics of places over geologic time. They investigate how climate has changed in specific world regions since the time of the dinosaurs and write paragraphs explaining their findings.

2001-01-01

371

Quantum Time  

Microsoft Academic Search

Normally we quantize along the space dimensions but treat time classically. But from relativity we expect a high level of symmetry between time and space. What happens if we quantize time using the same rules we use to quantize space? To do this, we generalize the paths in the Feynman path integral to include paths that vary in time as

John Ashmead

2010-01-01

372

Reinventing Time  

ERIC Educational Resources Information Center

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…

Technology Teacher, 2004

2004-01-01

373

Virtual time  

Microsoft Academic Search

Virtual time is a new paradigm for organizing and synchronizing distributed systems which can be applied to such problems as distributed discrete event simulation and distributed database concurrency control. Virtual time provides a flexible abstraction of real time in much the same way that virtual memory provides an abstraction of real memory. It is implemented using the Time Warp mechanism,

David R. Jefferson

1985-01-01

374

Magnesium Battery Disposal Characteristics.  

National Technical Information Service (NTIS)

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 Ag...

L. Soffer T. Atwater

1994-01-01

375

Ionospheric characteristics: a review  

SciTech Connect

The ionosphere is important to spacecraft charging because the thermal ions and electrons provide a significant current to a spacecraft surface. Low, mid, and high altitude ionospheric characteristics are discussed.

Rich, F.J.

1983-01-01

376

3D Characteristics  

NASA Technical Reports Server (NTRS)

Contributions to the Method of Characteristics in Three Dimensions, which previously received incomplete recognition, are reviewed. They mostly follow from a fundamental paper by Rusanov which led to several developments in Russia, described by Chushkin.

Holt, Maurice

1998-01-01

377

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 ...

378

Estimating Item Characteristics Curves.  

National Technical Information Service (NTIS)

A simulation study of the effectiveness of the following four item characteristic curve estimation programs was conducted: ANCILLES, OGIVIA (from U. S. Civil Service Commission); LOGIST (from Educational Testing Service); and simple transformations to the...

M. J. Ree

1978-01-01

379

Site Characteristics. Revised.  

National Technical Information Service (NTIS)

Revegetation success on disturbed sites is closely aligned to abiotic characteristics. Site-specific, microenvironmental conditions such as temperature and precipitation, effect revegetative success. Slope angle and aspect control radiation loads and thus...

C. Moore

1983-01-01

380

3D Characteristics.  

National Technical Information Service (NTIS)

Contributions to the Method of Characteristics in Three Dimensions, which previously received incomplete recognition, are reviewed. They mostly follow from a fundamental paper by Rusanov which led to several developments in Russia, described by Chushkin.

M. Holt

1998-01-01

381

Onboard Navigation Systems Characteristics  

NASA Technical Reports Server (NTRS)

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.

1979-01-01

382

Housing characteristics 1993  

SciTech Connect

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.

NONE

1995-06-01

383

Elapsed Time  

NSDL National Science Digital Library

This interactive Java applet allows the user to practice finding elapsed time using analog or digital clocks. Using the "See" mode the user advances a clock from the beginning time to the ending time and the applet calculates the elapsed time. Using the "Guess" mode, the user must calculate the elapsed time between the given beginning and ending times. Three difficulty levels allow the user to practice with hour, five minute, or single minute increments. An optional scoring feature allows the user to keep track of number correct, though this feature is optional.

2007-01-01

384

Characteristic times for lean blowoff in turbine combustors  

SciTech Connect

The purpose of this paper is to utilize a more complete set of new J85 lean blowoff data obtained at the Naval Air Propulsion Center (NAPC) and thus continue the validation of the model's application to annular combustors. A blowoff limit equation recommended here correlating data for two can combustors, as well as the GE and NAPC J85 data, suggests the model is able to characterize blowoff independently of combustor type.

Derr, W.S.; Mellor, A.M.

1986-01-01

385

Rise-Time Characteristics of Organic Solution Scintillators  

Microsoft Academic Search

A special demountable cathode-ray tube has been designed to produce electron-beam excitation of organic scintillator solutions. Solutions are irradiated through an electron-permeable window. The beam is swept across the window in 0.4 ?? 10-9 seconds. A 1P28 photomultiplier and traveling-wave oscilloscope are used in recording. About 25,000 mev of excitation energy is delivered per pulse and pulse oscillograms are free

D. F. McDonald; B. J. Dunn; J. V. Braddock

1960-01-01

386

The Pulse Waveform Characteristic Points Detection Based on Wavelet Transform  

Microsoft Academic Search

The pulse waveform characteristic points detection is very important for detecting cardiovascular parameters. A real-time algorithm based on wavelet transform (WT) is developed for detecting the characteristic points exactly. The algorithm combines the zero-crossing of a wavelet with one vanishing moment and the local extrema of a wavelet with two vanishing moment to improve the detection rate of characteristic points.

Qun Wang; Zhiwen Liu

2009-01-01

387

Residential Housing Characteristics Survey 1997  

NSDL National Science Digital Library

Specific information such as how many homes have PCs, modems and FAX machines or how home appliance usage has changed over time (1978-1997) can now be obtained in this recently-released Residential Housing Characteristics Survey by the US Energy Information Administration. Nearly two decades of Regional Energy Consumption Surveys (RECS) on US households and their energy is contained on site in addition to supplementary maps, a glossary of terms, and documentation of EIA survey methods and data quality. To further facilitate research, the EIA provides a Data Table Home Page where users may choose variables and access data tables directly on site.

1998-01-01

388

Physical characteristics of polymethylmethacrylate scintillator SOFG-120  

NASA Astrophysics Data System (ADS)

Characteristics of the polimethylmetacrylate scintillator which is used for the fast scintillating trigger in the liquid argon neutrino detector of the Tagged Neutrino Facility are studied. Scintillator SOFG-120 consists of PMMA-85%, naphtalene-14%, PPO-0.8%, and POPOP-0.08%. As main characteristics, spectral emission, light output (50% NE-110), time resolution 4.8 ns, and attenuation length (for sheet 1265x333x22 mm(exp 3)) lambda approximately = m were obtained.

Belikov, S. V.; Gurzhiev, S. N.; Dyachkov, A. P.

389

Thrombin Time  

MedlinePLUS

... this website will be limited. Search Help? Thrombin Time Share this page: Was this page helpful? Also ... for monitoring dabigatran therapy? 1. Can the thrombin time be performed in my doctor's office? With the ...

390

Entropic Time  

SciTech Connect

The formulation of quantum mechanics within the framework of entropic dynamics includes several new elements. In this paper we concentrate on one of them: the implications for the theory of time. Entropic time is introduced as a book-keeping device to keep track of the accumulation of changes. One new feature is that, unlike other concepts of time appearing in the so-called fundamental laws of physics, entropic time incorporates a natural distinction between past and future.

Caticha, Ariel [Department of Physics, University at Albany-SUNY, Albany, NY 12222 (United States)

2011-03-14

391

Universal Time  

NSDL National Science Digital Library

This is a lesson plan for an activity that explores time zone math. Learners will translate their local time to times in other zones around the world and work with the concept of Universal Time, specifically in reference to the reporting, description and analysis of solar flares and coronal mass ejections. This is activity 10 from Exploring Magnetism Guide 3: Magnetic Mysteries of the Aurora educator guide.

392

Telling Time  

NSDL National Science Digital Library

Help your child learn how to tell time on a digital and analog clock. Practice Telling Time with this fun game! Then, match the apple clock with the digital clock to show the correct Time! Finally, is it A.M. or P.M.? Practice with this fun game! ...

Popwell, Ms.

2010-10-03

393

Sequencing Time  

NSDL National Science Digital Library

In this activity, students gain an understanding of relative and numerical time by placing events in sequence and assigning relative times to the events. This will familarize them with the methods used by scientists to develop the geologic time scale. This activity contains objectives, materials, procedure, and extensions.

2007-12-12

394

Geologic Time.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science topics, the booklet provides those interested in geologic time with an introduction to the subject. Separate sections discuss the relative time scale, major divisions in geologic time, index fossils used as guides for telling the age of rocks, the atomic scale, and the age of the earth.…

Newman, William L.

395

Reaction Time  

NSDL National Science Digital Library

In this activity, learners explore reaction time and challenge themselves to improve their coordination. Do you want to move faster? Catch that ball that you never seem to see in time? Use a simple test to help you improve your reaction (or response) time.

Science, New Y.

1999-01-01

396

Time Honoured  

ERIC Educational Resources Information Center

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…

Campbell, Mora; Timmerman, Peter

2007-01-01

397

Relative Timing  

Microsoft Academic Search

Relative Timing is introduced as an informal method for aggressive asynchronous design. It is demonstrated on three example circuits (C-Element, FIFO, and RAPPID Tag Unit), facilitating transformations from speed-independent circuits to burst-mode, relative timed, and pulse-mode cir- cuits. Relative timing enables improved performance, area, power and testability in all three cases. The design of RAPPID, the asynchronous instruction length decoder,

Ken S. Stevens; Shai Rotem; Ran Ginosar

1999-01-01

398

Time Machine  

NSDL National Science Digital Library

In this lesson students will experience how geological and biological events have occurred in a clear sequence of vast but measured time. Students are taken on a simulated voyage backward in time, to the beginning of our planet. They witness that beginning, the origin of life, and a number of key events leading to the present. This becomes a dramatic experience, involving body and mind, helping students to relate physically at least to the relative timing of events in geological and biological history, if not to the absolute vastness of that time.

Flammer, Larry

399

Geologic Time  

NSDL National Science Digital Library

The Earth is very old -- 4.5 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.

Newman, William L.

1997-01-01

400

The Variance Reaction Time Model  

ERIC Educational Resources Information Center

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…

Sikstrom, Sverker

2004-01-01

401

Time response of plastic scintillators  

Microsoft Academic Search

Time-response characteristics of eight commercial plastic scintillators ; have been studied. Samples were excited by 50 ps electron or bremsstrahlung ; pulses. Sampling techniques were used to record the signal from a fast vacuum ; photodiode. Effects of surface preparation on time response were studied. The ; observed fwhm (in ns) for the three fastest plastics was 1.5, 2.0, and

P. B. Lyons; J. Stevens

1974-01-01

402

Real-Time Complex Systems.  

National Technical Information Service (NTIS)

We developed modified linear hybrid automata models for complex real- time tasks, e.g. tasks that have complex internal behaviors, may interact or synchronize in complex ways, and may have variable or not-fully-known timing characteristics. We report on i...

S. Vestal

2004-01-01

403

Magnesium battery disposal characteristics  

Microsoft Academic Search

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

Louis Soffer; Terrill Atwater

1994-01-01

404

Characteristics of USB noise  

NASA Technical Reports Server (NTRS)

An extensive series of noise measurements, for a variety of geometric and operational parameters, was made on models of upper surface blowing (USB) powered lift systems. The data obtained were analyzed and the effects and trends of parametric variation defined. The behavior and nature of USB noise and the design of USB systems with low noise characteristics is examined.

Gibson, J. S.; Searle, N.

1976-01-01

405

Convention Center Operating Characteristics  

Microsoft Academic Search

While convention centers have continued to grow and expand, the basic facts about this segment of the hospitality industry have not been widely available. This article seeks to change that situation by undertaking exploratory research that takes the most important characteristics of convention centers (Adams, 1984; Fenich, 1992; Leo & Levite, 1986; Zia, 1988) and then provides descriptive statistics for

George Fenich

1999-01-01

406

Tunneling characteristics of graphene  

Microsoft Academic Search

Negative differential conductance and tunneling characteristics of two-terminal graphene devices are observed before and after electric breakdown, respectively. The former is caused by the strong scattering under a high E-field, and the latter is due to the appearance of a tunneling barrier in graphene channel induced by a structural transformation from crystalline graphene to disordered graphene because of the breakdown.

Young Jun Shin; Gopinadhan Kalon; Jaesung Son; Jae Hyun Kwon; Jing Niu; Charanjit S. Bhatia; Gengchiau Liang; Hyunsoo Yang

2010-01-01

407

Characteristic Curves of PEMFC  

NSDL National Science Digital Library

This in-class exercise will allow students hands-on experience working with a proton exchange membrane fuel cell, or PEMFC. The class will examine the characteristic curve of one of these fuel cells and measure the voltage and current output of the cell. Step by step instructions are provided for the experiment. This document may be downloaded in PDF file format.

2012-07-11

408

Maintenance Workforce Characteristics.  

National Technical Information Service (NTIS)

We identified the characteristics of the FY01 DoD maintenance workforce, placing it in the larger context of the total DoD workforce and analyzing trends from FY97 to FY01. We evaluated the workforce in terms of age, years of service, retirement eligibili...

R. A. Clifford J. Callender N. T. O'Meara

2003-01-01

409

Geological Time  

NSDL National Science Digital Library

"Why do engineers need to know about geologic time?" That question is answered in this resource from the University of Saskatchewan's Department of Civil and Geological Engineering. Provided here is a discussion of the concepts of geological time; relative dating methods, such as correlation; and absolute dating methods, such as radiometric methods. Diagrams and charts are included to demonstrate these complex concepts.

2008-04-17

410

Time Management  

ERIC Educational Resources Information Center

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…

Stoilov, Todor, Ed.

2012-01-01

411

Virtual Time  

Microsoft Academic Search

Virtual time is a broad, new paradigm for organizing and synchronizing distributed systems, subsuming such heretofore distantly related problems as distributed discrete event simulation and distributed database concurrency control. It is an abstraction of real time in much the same way that virtual memory is an abstraction of real memory, and it reorganizes the concepts of concurrency and synchronization in

David Jefferson

1983-01-01

412

The characteristics of colliding black holes  

NASA Astrophysics Data System (ADS)

I review the characteristic initial value problem, its implementation as a robust computational algorithm for a 4-dimensional vacuum space-time (the PITT NULL CODE) and its application to the calculation of gravitational waveforms emitted by black holes. I describe the potential applications of the code to the binary black hole problem, via Cauchy-characteristic matching or pure characteristic evolution. In particular, the event horizon is itself a characteristic hypersurface and can be treated by characteristic methods as a stand-alone object. This allows an analytic treatment of the intrinsic geometry of the event horizon for colliding black holes which produces the pair-of-pants horizon found in the numerical simulation of the head-on-collision of black holes and the initially toroidal event horizon found in the simulation of a collapsing, rotating cluster. Most previous studies of black hole formation and merger are restricted to the axisymmetric case. However, axisymmetric horizons, like the Schwarzschild horizon, are non-generic. When applied to a non-axisymmetric horizon, the characteristic approach reveals substantially new features. In particular, coalescing black holes generically go through a toroidal phase before they become spherical. In a bigger picture, this analytic model of the event horizon provides part of the data for a simulation of the space-time exterior to a binary merger by means of the null code.

Winicour, Jeffrey

1999-11-01

413

The Characteristic Treatment of Black Holes  

NASA Astrophysics Data System (ADS)

The characteristic initial value problem has been successfully implemented as a robust computational algorithm (the PITT NULL CODE) to evolve 4-dimensional vacuum space-times. It has been applied to the calculation of gravitational waveforms emitted by black holes and to the event horizon structure in the merger of black holes. The characteristic code also has potential application to the binary black hole problem via Cauchy-characteristic matching. Because the event horizon is itself a characteristic hypersurface, it can be analyzed by characteristic techniques as a stand-alone object. We have developed an analytic conformal model of null hypersurfaces which gives new insight into the intrinsic geometry of the pair-of-pants horizon found in the numerical simulation of the head-on collision of black holes and into the initially toroidal horizon found in the simulation of a collapsing, rotating cluster. Most studies of black hole formation and merger have been restricted to axisymmetry. However, axisymmetric horizons, like the Schwarzschild horizon, are non-generic. When applied to a non-axisymmetric horizon, the characteristic approach reveals substantially new features. In particular, coalescing black holes generically go through a toroidal phase before they become spherical. The conformal structure of the event horizon supplies part of the data for a simulation of the exterior space-time. This provides a new way to calculate the post-merger waveforms from a binary black hole inspiral.

Winicour, J.

414

Screen Time  

NSDL National Science Digital Library

This game asks you a series of questions about how much time you spend in front of a screen, not being active. It begins by pointing out that since we spend a lot of time in front of computer screens at work or school, additional time at home can really affect how healthy we are. It asks how much time you spend watching TV, playing computer games, and using the computer each day. It then adds up the total amount of screen time you spend every day, and calculates how many hours you spend a year in front of a screen. It also tells you if that's a healthy amount, and suggests ways to stay active while in front of screens.

Omsi

2007-01-01

415

Time Clocks  

NSDL National Science Digital Library

This exercise can be used to demonstrate changes in the Earth through time, and the length of time it took for those changes to take place. A list of Important Dates in Earth History is provided that contains the dates of the events shown on a time clock. The teacher can pick events from the list of key events and calculate (or have students calculate) the time for the key events they wish to use. A page-size image of the clock can be printed and turned into an overhead transparency. To better demonstrate the changes since the beginning of the Paleozoic Era, the same exercise could be done the second day of class, using only the last 570 million years of time.

Greb, Stephen

416

Finding time.  

PubMed

We understand time through our models of it. These are typically models of our physical chronometers, which we then project into our subjects. A few of these models of the nature of time and its effects on the behavior of organisms are reviewed. New models, such as thermodynamics and spectral decomposition, are recommended for the potential insights that they afford. In all cases, associations are essential features of timing. To make them, time must be discretized by stimuli such as hours, minutes, conditioned stimuli, trials, and contexts in general. Any one association is seldom completely dominant, but rather shares control through proximity in a multidimensional space, important dimensions of which may include physical space and time as rendered by Fourier transforms. PMID:23973706

Killeen, Peter R

2014-01-01

417

Bleeding time  

MedlinePLUS

Bleeding time is a blood test that looks at how fast small blood vessels in the skin close to stop you from bleeding. ... deep enough to cause a tiny amount of bleeding. The blood pressure cuff is immediately deflated. Blotting ...

418

Creative Time  

NSDL National Science Digital Library

Creative Time curates, funds, and organizes public art projects, so their website is a reference of the form dating back to 1975. You can browse by program name, date or artist's name (the most common of these being "multiple artists.") Creative Time's roster also includes familiar names such as Marina Abramovic, Doug Aitken, Laurie Anderson, David Byrne, Paul Chan, Jenny Holzer, Gary Hume, Vik Muniz, Takashi Murakami, Shirin Neshat, Steve Powers, and Cai Guo-Qiang. For example, Creative Time worked with Cai Guo-Qiang to present Light Cycle, in 2003, to celebrate the 150th anniversary of New York City's Central Park; in 2008 David Byrne's Playing the Building transformed the Battery Maritime Building in Lower Manhattan into a massive sound sculpture that visitors could play using a keyboard; and in summer 2012 Creative Time and multiple artists hosted a sandcastle competition at Far Rockaway, possibly the start of a new New York summer tradition.

2012-08-31

419

Timing During Interruptions in Timing  

ERIC Educational Resources Information Center

Duration and location of breaks in time interval production were manipulated in various conditions of stimulus presentation (Experiments 1-4). Produced intervals shortened and then stabilized as break duration lengthened, suggesting that participants used the break as a preparatory period to restart timing as quickly as possible at the end of the…

Fortin, Claudette; Bedard, Marie-Claude; Champagne, Julie

2005-01-01

420

Wuda Time  

NSDL National Science Digital Library

The Wuda Time project management tool is designed to help individuals keep track of their dedication to various tasks and operations. Visitors can sign up right on the site to have instant access to this powerful tool. It's easy to use and users can prioritize certain tasks with a color-coded system or designate certain task completion times. This version is compatible with all operating systems.

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