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1

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

2

Numerical simulation of laminar-turbulent transition in a spatially-developing flat plate wake  

NASA Technical Reports Server (NTRS)

Laminar-turbulent transition of an incompressible flat-plate wake is investigated by direct numerical integration of the Navier-Stokes equations. For the numerical integration, a combination of finite-difference and spectral methods along with an ADI/Crank-Nicolson/Adams-Bashforth time integration scheme is employed. Subject to 2D forcing, the wake exhibited a rapidly-growing fundamental disturbance that quickly saturated. This saturation was due partly to the stabilizing effect of the mean flow distortion. Downstream of the saturation point, disturbance energy was concentrated in the fundamental disturbance, the second harmonic, and the mean flow distortion component. At large amplitude levels, a Karman vortex street formed. Variations in the 2D forcing level did not alter the qualitative behavior of the disturbances. Simulations of 3D breakdown indicates that the presence of large-amplitude, 2D disturbances tends to initially suppress small-amplitude 3D disturbance growth. Following this initial suppression, a resumption of 3D growth is observed that may have been due to a secondary instability mechanism. For high levels of 3D disturbance energy, lambda-shaped vortical structures formed between adjacent Karman vortices.

Dratler, D. I.; Fasel, H. F.

1993-01-01

3

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

E-print Network

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

Seshasayanan, K

2015-01-01

4

On the role of secondary instabilities in laminar-turbulent transition of 2D and 3D boundary layers  

NASA Technical Reports Server (NTRS)

The accurate prediction of laminar/turbulent transition is one of the fundamental problems in engineering fluid mechanics. There is almost unanimous consent that such a transition criterion should come from stability theory. Linear primary stability theory describes the initial stage of transition, but falls short of predicting transition. Only in conjunction with empirical correlations, the widely used e(sup n) method is obtained, which, however, lacks a solid physical base. Three-dimensional secondary instabilities are known to play an important role in the transition process. However, no use has been made so far of secondary instabilities, instability interactions or wave resonances to define a 'transition location'. The paper summarizes new attempts to identify certain interaction and resonance phenomena within the laminar-turbulent transition regime in two and three-dimensional boundary layers which are associated with rapid structural and temporal changes of fluctuations beyond their exponential growths.

Dallman, Uwe; Fischer, Thomas M.; Koch, Werner; Bippes, Hans

1992-01-01

5

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

6

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

7

A parametric study of LES on laminar-turbulent transitional flows past an airfoil  

NASA Astrophysics Data System (ADS)

Low-Reynolds-number aerodynamic performance of small-sized air vehicles is an area of increasing interest. In this study, low-Reynolds-number flows past an SD7003 airfoil are investigated to understand important viscous features of laminar separation and transitional flow followed by the complicated behavior of the flow reattachment process. In order to satisfy the three-dimensional (3D) requirement of the code, a simple “3D wing” is constructed from a two-dimensional (2D) airfoil. A parametric study of large eddy simulation (LES) on the airfoil flows at Re=60,000 is performed. Effects of grid resolution and sub-grid scale (SGS) models are investigated. Although 3D effects cannot be accurately captured owing to the limitation of the grid resolution in the spanwise direction, the preliminary LES calculations do reveal some important flow characteristics such as leading-edge laminar separation and vortex shedding from the primary laminar separation bubble on the low-Reynolds-number airfoil.

Yuan, W.; Xu, H.; Khalid, M.; Radespiel, R.

2006-01-01

8

Experiments on the effect of laminar-turbulent transition on the SWBLI in H2K at Mach 6  

NASA Astrophysics Data System (ADS)

This paper presents the results of the experiments performed in the hypersonic wind tunnel H2K in the framework of the ESA technology research project "laminar to turbulent transition in hypersonic flows". The investigations include the free boundary-layer transition on a flat plate as well as the influence of a shock wave-boundary layer interaction on the transition. The shock is created by a wedge with a small angle of attack resulting in a moderate shock intensity. The experiments were performed at Mach 6.0, at three different unit Reynolds numbers and with a translational displacement of the shock generator. Besides the optical methods—Schlieren photography and infrared thermography—several intrusive sensors were used. High-speed measurements were carried out using PCB and atomic layer thermo pile sensors. Kulite sensors were used for low- and mid-speed pressure measurements. The data analysis includes the comparison of the absolute values, the frequency spectra and wavelets and their distributions in time and space.

Willems, Sebastian; Gülhan, Ali; Steelant, Johan

2015-03-01

9

Characteristic Time Scales of Characteristic Magmatic Processes and Systems  

NASA Astrophysics Data System (ADS)

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

Marsh, B. D.

2004-05-01

10

Studies of "Kapustinsky's" light pulser timing characteristics  

E-print Network

We present the results of studies of a nanosecond light pulser built following J.S.Kapustinsky et al original design 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.

B. K. Lubsandorzhiev; Y. E. Vyatchin

2004-10-29

11

Studies of "Kapustinsky's" light pulser timing characteristics  

E-print Network

We present the results of studies of a nanosecond light pulser built following J.S.Kapustinsky et al original design 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

2006-01-01

12

Stochastic Modeling of Laminar-Turbulent Transition  

NASA Technical Reports Server (NTRS)

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

Rubinstein, Robert; Choudhari, Meelan

2002-01-01

13

Predicting river travel time from hydraulic characteristics  

USGS Publications Warehouse

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

Jobson, H.E.

2001-01-01

14

Loudspeaker Phase Characteristics and Time Delay Distortion: Part 2.  

E-print Network

Loudspeaker Phase Characteristics and Time Delay Distortion: Part 2. RICHARD C. HEYSER Jet counterpart. A derivation is obtained for the effect of a loudspeaker's imperfect frequency response] the defini- backward. Because of considerable mathematical com- tion of loudspeaker frequency response

Allen, Jont

15

Time-reversal characteristics of quantum normal diffusion: time-continuous models  

NASA Astrophysics Data System (ADS)

In quantum map systems exhibiting normal diffusion, time-reversal characteristics converge to a universal scaling behavior which implies a prototype of irreversible quantum process [H.S. Yamada, K.S. Ikeda, Eur. Phys. J. B 85, 41 (2012)]. In the present paper, we extend the investigation of time-reversal characteristic to time-continuous quantum systems which show normal diffusion. Typical four representative models are examined, which is either deterministic or stochastic, and either has or not has the classical counterpart. Extensive numerical examinations demonstrate that three of the four models have the time-reversal characteristics obeying the same universal limit as the quantum map systems. The only nontrivial counterexample is the critical Harper model, whose time-reversal characteristics significantly deviates from the universal curve. In the critical Harper model modulated by a weak noise that does not change the original diffusion constant, time-reversal characteristic recovers the universal behavior.

Yamada, H. S.; Ikeda, K. S.

2012-06-01

16

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

17

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. PMID:22046149

Kuznetsov, Nikita A.; Wallot, Sebastian

2011-01-01

18

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.

19

Real-Time Mapping alert system; characteristics and capabilities  

USGS Publications Warehouse

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

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

1995-01-01

20

Meteor trail characteristics observed by high time resolution lidar  

NASA Astrophysics Data System (ADS)

We report and analyse the characteristics of 1382 meteor trails based on a sodium data set of ~ 680 h. The observations were made at Yanqing (115.97° E, 40.47° N), China by a ground-based Na fluorescence lidar. The temporal resolution of the raw profiles is 1.5 s and the altitude resolution is 96 m. We discover some characteristics of meteor trails different from those presented in previous reports. The occurrence heights of the trails follow a double-peak distribution with the peaks at ~ 83.5 km and at ~ 95.5 km, away from the peak height of the regular Na layer. 4.7% of the trails occur below 80 km, and 3.25% above 100 km. 75% of the trails are observed in only one 1.5 s profile, suggesting that the dwell time in the laser beam is not greater than 1.5 s. The peak density of the trails as a function of height is similar to that of the background sodium layer. The raw occurrence height distribution is corrected taking account of three factors which affect the relative lifetime of a trail as a function of height: the meteoroid velocity (which controls the ratio of Na/Na+ ablated); diffusional spreading of the trail; and chemical removal of Na. As a result, the bi-modal distribution is more pronounced. Modelling results show that the higher peak corresponds to a meteoroid population with speeds between 20 and 30 km s-1, whereas the lower peak should arise from much slower particles in a near-prograde orbit. It is inferred that most meteoroids in this data set have masses of ~ 1 mg, in order for ablation to produce sufficient Na atoms to be detected by lidar. Finally, the evolution of longer-duration meteor trails is investigated. Signals at each altitude channel consist of density enhancement bursts with the growth process usually faster than the decay process, and there exists a progressive phase shift among these altitude channels.

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

2014-10-01

21

Termination time of characteristics of Hamilton-Jacobi equations  

NASA Astrophysics Data System (ADS)

This paper concerns with Hamilton-Jacobi equations of n space variables, where the Hamiltonians are convex and the initial data are admitted to be unbounded. First, we study the characteristics for the general case of initial data being Lipschitz by using the Hopf formula. Sufficient and necessary conditions are established for guaranteeing a characteristic to start from y 0 at t = 0 with direction DH( P 0) and for a characteristic never terminating on a singularity of the solution. Next, in the case of initial data being C 2, we prove that the set of singularities consists of at most countable path-connected components, which is an extension of (Zhao et al. in J Hyperbolic Differ Equ 5(3):663-680, 2008) and (Li in Sci Sinica 22(9):979-990, 1979).

Li, Tian-Hong; Li, Xing

2013-06-01

22

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

23

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

24

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

25

EMBAYMENT CHARACTERISTIC TIME AND BIOLOGY VIA TIDAL PRISM MODEL  

EPA Science Inventory

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

26

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

27

Spawning by California Golden Trout: Characteristics of Spawning Fish, Seasonal and Daily Timing, Redd Characteristics, and Microhabitat Preferences  

Microsoft Academic Search

We investigated the spawning biology of California golden trout Oncorhynchus mykiss aguabonita, an endemic subspecies of rainbow trout, in the Golden Trout Wilderness, California. We investigated the influence of stream temperature on the seasonal and daily timing of spawning, measured characteristics of completed redds, and quantified microhabitat use and preferences by spawning females. We also quantified size at sexual maturity,

Roland A. Knapp; Vance T. Vredenburg

1996-01-01

28

Characteristic relaxation times and their invariance to thermodynamic conditions  

E-print Network

-Debye behavior; (ii) the dynamic crossover at which derivatives of the relaxation time and strength exhibit the nature of the intermolecular potential, thus providing fundamental insights into chemical structure evident when crystallization is avoided (for example, by quenching); temperature changes near the glass

Weeks, Eric R.

29

Bilinear System Characteristics from Nonlinear Time Series Analysis  

SciTech Connect

Detection of changes in the resonant frequencies and mode shapes of a system is a fundamental problem in dynamics. This paper describes a time series method of detecting and quantifying changes in these parameters for a ten degree-of-freedom bilinear system excited by narrow band random noise. The method partitions the state space and computes mode frequencies and mode shapes for each region. Different regions of the space may exhibit different mode shapes, allowing diagnosis of stiffness changes at structural discontinuities. The method is useful for detecting changes in the properties of joints in mechanical systems or for detection of damage as the properties of a structure change during use.

Hunter, N.F. Jr.

1999-02-08

30

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

31

Cases where finding the minimum entropy coloring of a characteristic graph is a polynomial time problem  

E-print Network

In this paper, we consider the problem of finding the minimum entropy coloring of a characteristic graph under some conditions which allow it to be in polynomial time. This problem arises in the functional compression ...

Feizi, Soheil

32

Characteristics of the melatonin signal that provide the photoperiodic code for timing seasonal  

E-print Network

Characteristics of the melatonin signal that provide the photoperiodic code for timing seasonal studies to identify important features of the circadian pattern of melatonin secretion which provide of experiments evaluated two conceptual models of how melatonin codes for daylength : the circadian timing

Boyer, Edmond

33

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

34

Combustion characteristics of a direct-injection natural gas engine under various fuel injection timings  

Microsoft Academic Search

The combustion characteristics of a direct-injection natural gas engine under various fuel injection timings were investigated. The results showed that fuel injection timing had a large influence on the engine performance, combustion and emissions and these influences became largely in the case of late injection. Over-late injection would supply insufficient time for the fuel–air mixing of the late part of

Ke Zeng; Zuohua Huang; Bing Liu; Liangxin Liu; Deming Jiang; Yi Ren; Jinhua Wang

2006-01-01

35

Time-dependent regimes of a Bursian diode II: Characteristic features of nonlinear oscillations  

SciTech Connect

A study is made of the physical phenomena characteristic of nonlinear oscillations in a Bursian diode in the regime with a virtual cathode. The question of how the shape of the oscillations varies as the beam current density increases is investigated for the first time. Sharp jumps in the time evolution of the convective current are revealed, and their causes are explained. The reason is found for the onset of long-lived electrons, and their properties are analyzed.

Kuznetsov, V. I.; Ender, A. Ya. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2010-03-15

36

Bacterial synthesized cellulose nanofibers; Effects of growth times and culture mediums on the structural characteristics  

Microsoft Academic Search

In this study the effects of growth times and culture mediums on the structural characteristics of bacterial cellulose have been investigated. Bacterial cellulose (BC) nanofibers were synthesized by Gluconacetobacter xylinus. BC pellicles were compared using SEM, FT-IR and X-ray diffraction techniques. The crystallinity index (CrI) and crystallite size (CrS) were calculated based on X-ray measurements. Three growth times (7, 14

Somayeh Sheykhnazari; Taghi Tabarsa; Alireza Ashori; Alireza Shakeri; Masood Golalipour

2011-01-01

37

Working control system for space-time characteristics of industrial IR lasers  

Microsoft Academic Search

This paper discusses the problem of monitoring emission parameters of lasers in industrial use. The principles of a system for working control and analysis of the space-time characteristics of these IR lasers are considered. The authors explain how the IR emission of a laser is applied to a beam splitter and the component is diverted to the aperture of a

S. A. Dvoretskii; L. M. Zaitsev; D. G. Kvirikadze; V. M. Klyuchnikov; L. A. Pospelova; M. V. Senashenko; E. B. Shelemin

1986-01-01

38

Length-speed ratio (LSR) as a characteristic for moving elements real-time classification  

Microsoft Academic Search

In this article, the length-speed ratio (LSR) is proposed as a basic characteristic for the real-time detection of moving objects. We define the LSR of a uniform moving zone as the relation between its length in the direction of motion and the speed of this motion. For a given zone of the image with uniform gray level (or patch), the

Miguel A. Fern; A. Fern

39

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

40

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

41

Iterative approach to the characteristic time for chemical reactions of type A + B ! C + D  

E-print Network

The analytic solution for the kinetic description of binary reactions can be seen as the continuum version of a basic discrete iterate mapping. This fact allows a clear definition of the reaction characteristic time which takes the backward effect into account.

R. Aldrovandi

2013-10-13

42

Influence of patient characteristics on care time in patients hospitalized with schizophrenia  

PubMed Central

Background In the current Japanese payment system for the treatment of psychiatric inpatients, the length of hospital stay and nurse staffing levels are key determinants of the amount of payment. These factors do not fully reflect the costs of care for each patient. The objective of this study was to clarify the relationship between patient characteristics and their care costs as measured by “care time” for patients with schizophrenia. Methods Patient characteristics and care time were investigated in 14,557 inpatients in 102 psychiatric hospitals in Japan. Of these 14,557 inpatients, data for 8,379 with schizophrenia were analyzed using a tree-based model. Results The factor exerting the greatest influence on care time was ”length of stay”, so subjects were divided into 2 groups, a “short stay group” with length of stay ?104 days, and “long stay group” ?105 days. Each group was further subdivided according to dependence with regard to “activities of daily living”, “psychomotor agitation”, “verbal abuse”, and “frequent demands/repetitive complaints”, which were critical variables affecting care time. The mean care time was shorter in the long-stay group; however, in some long-stay patients, the mean care time was considerably longer than that in patients in the short-stay group. Conclusion The results of this study suggest that it is necessary to construct a new payment system reflecting not only length of stay and nurse staffing levels, but also individual patient characteristics. PMID:25187720

Sugibayashi, Yukiko; Yoshimura, Kimio; Yamauchi, Keita; Inagaki, Ataru; Ikegami, Naoki

2014-01-01

43

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

PubMed Central

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

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

2014-01-01

44

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

PubMed

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

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

2014-01-01

45

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

NASA Astrophysics Data System (ADS)

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

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

46

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

47

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

48

Using time series analysis to study the relationship of precipitation to other climate characteristics across different time scales  

NASA Astrophysics Data System (ADS)

The occurrence, duration and intensity of precipitation are highly related to other climate characteristics, such as air pressure, relative humidity and temperature. At the same time, short-term precipitation variability at a point is nested into trends at much larger temporal (and spatial) scales. Most climate researchers describe regional precipitation either with reference to historical observations or by making generalized forecasts of decadal, annual, or seasonal trends informed by global or regional climate models. Despite its importance in runoff generation, infiltration, erosion, and other processes, trends in short time scale precipitation remain poorly characterized. In this study, hourly historical precipitation in six coastal cities (New York, Philadelphia, Providence, Boston, and Baltimore) is compared to longer (e.g. daily, monthly, annual) precipitation trends, as well as to other hourly climate measurements (e.g. relative humidity and air pressure) using time series analysis. The results describe the dependency of fine scale precipitation patterns on coarser ones, as well as relate micro-scale precipitation patterns to trends in other hourly climate characteristics. Historical observations reveal a positive dependence of cumulative rainfall depth across different temporal scales (e.g. hourly on daily, daily on monthly, monthly on annual) in all locations, while temporal trends were not obvious. The probability of rain is negatively correlated to air pressure throughout the year despite seasonal supply of humidity from the ocean.

Yu, Z.; Montalto, F. A.

2012-12-01

49

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

50

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

SciTech Connect

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

Advani, S.H.; Lee, T.S. [Lehigh Univ., Bethlehem, PA (United States); Moon, H. [Ohio State Univ., Columbus, OH (United States)

1992-10-01

51

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

SciTech Connect

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

Advani, S.H.; Lee, T.S. (Lehigh Univ., Bethlehem, PA (United States)); Moon, H. (Ohio State Univ., Columbus, OH (United States))

1992-10-01

52

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

PubMed

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 canary grass (Phalaris arundinacea), and sainfoin (Onobrychis viciifolia). These crops are considered as fuels for thermal conversion. From September 2002 to April 2003, biomass was sampled monthly, and the effects of harvest time on the fuel characteristics of the five crops were studied. With respect to ash and some undesired element contents in biomass, a delayed harvest in spring resulted in a better fuel quality than a traditional harvest in autumn. Of the five species, indigo bush and sand willow had the lowest ash contents when harvested in spring. Switch grass is a promising herbaceous energy crop in semiarid areas in terms of its yield, fuel characteristics, and low water use. Chlorine had the most significant correlation with harvest time and ash content in the biomass. In a comparison with the biofuel crops in Europe and North America, a much higher proportion of chlorine was found in all examined plants. The results from this study indicate that an energy crop with delayed harvest may extend fuel resources and conserve soil in semiarid regions in northern China, practices that will help maintain and improve economical and ecological sustainability. PMID:17382539

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

2008-02-01

53

Time domain characteristics of UWB signal transmitting through a finitely conducting slab  

NASA Astrophysics Data System (ADS)

A new approximate time domain reflection coefficient, the relationship between the reflection and refraction on slab surfaces, and expression for propagation loss term within the slab in time domain are deduced in this paper. By using time domain convolution of the three terms, a simplified analytic solution for UWB impulse signal transmitting through a finitely conducting slab is proposed. This solution takes into account the frequency range from 3.1 to 10.6 GHz and is suitable for most common building construction materials within indoor environment. The simulations of incident monocycle transmitting through slabs of different materials and thickness are presented by applying the simplified time domain analytic solution to illustrate the characteristics of transmission and give some results in simplification of transmission field analysis in indoor channel modeling.

Wang, Yang; Zhang, Naitong; Zhang, Qinyu; Zhang, Zhongzhao

2007-11-01

54

Characteristics and time evolution of a hollow cathode produced glow discharge plasma in air  

NASA Astrophysics Data System (ADS)

Current radar systems use mechanical directors and phased array technology for beam steering. Use of a sheet plasma as a microwave reflector promises several advantages over these methods. Operation is inherently broad-band, since all frequencies below the plasma frequency are reflected. The orientation and shape of the reflector may be changed directly through electronic control without resort to moving parts or expensive RF switches. The relatively fast plasma formation and extinction times ([/approx]10/ /mus) allow for rapid redirection of the microwave beam. An experimental system, dubbed the Agile Mirror, has been constructed using a cylindrical LexanTM vacuum chamber suspended within a water cooled Helmholtz coil pair capable of producing a uniform 500 Gauss field. Using this system we have created plasmas capable of reflecting 10 GHz microwaves with characteristics comparable to that of a plane metallic reflector. Most previous glow discharge work has concentrated either on the DC characteristics, or on the very early evolution (<1-2 ?s), of the discharge. To create a practical agile mirror direction, we must be able to produce a stable, flat, homogeneous plasma sheet with predictable characteristics timescales from 5 ?s to 1 ms-a regime where little pertinent quantitative data exists. This work concentrates on diagnosing the time resolved behavior of the agile mirror plasma during the mid-time, from t = 5-300 ?s, in a regime which accentuates observed changes in the discharge circuit characteristics. Measurements on an air discharge produced using VD/approx2.2 kV, p ? 208 mTorr, and B ? 250 G reveal an ne=1011/ cm-3,/ Te=1[-]3 eV plasma with distinct negative glow, Faraday dark space, and positive column regions. Analysis of time resolved potential, temperature, and spectroscopic data reveal that this discharge transitions-on time scales of [/approx]100/ /mus-into a pure negative glow discharge. The characteristics and evolution of the discharge are highly reproducible. A computer model of the discharge reveals that heating of the background gas is responsible for the transition. Implications for operation of the agile mirror discharge as a plasma mirror are discussed.

Gregor, Joseph Atilla

55

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

56

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

57

Characteristics of the boundary-layer equations of the minimum time-to-climb problem  

NASA Technical Reports Server (NTRS)

In many singular perturbation solutions of optimal control problems, the most difficult numerical task is to solve the boundary-layer equations. However, these equations have a special structure that may often be used to expedite their solution. This paper begins by noting the general nature of the boundary-layer equations for optimal control problems. These results are then applied to the aircraft minimum time-to-climb problem. A specific numerical example is considered to illustrate the characteristics of the solution of the boundary-layer equations for this problem.

Ardema, M. D.

1976-01-01

58

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

59

Associations of Neighborhood Characteristics with Sleep Timing and Quality: The Multi-Ethnic Study of Atherosclerosis  

PubMed Central

Study Objectives: To investigate the associations of specific neighborhood features (disorder, safety, social cohesion, physical environment, and socioeconomic status) with sleep duration and quality. Design: Cross-sectional. One wave of a population-based study (Multi-Ethnic Study of Atherosclerosis). Setting: Community-dwelling participants in New York, NY and Los Angeles, CA. Participants: There were 1,406 participants (636 males, 770 females). Interventions: NA. Measurements and Results: Sleep was assessed using reported hours of sleep, the Epworth Sleepiness Scale, and insomnia symptoms. Neighborhood characteristics were assessed via questionnaires administered to neighbors of study participants and were aggregated to the neighborhood (census tract) level using empirical Bayes estimation. An adverse social environment (characterized by high disorder, and low safety and social cohesion) was associated with shorter sleep duration after adjustment for the physical environment, neighborhood and individual-level socioeconomic status (SES), and other short sleep risk factors (mean difference per standard deviation increase in summary social environment scale 0.24 h 95% confidence interval 0.08, 0.43). Adverse neighborhood social and physical environments, and neighborhood SES were associated with greater sleepiness, but associations with physical environments were no longer statistically significant after adjustment for sociodemographic characteristics. Neighborhood SES was a weaker and less consistent predictor of specific measures of neighborhood social and physical environments. Neighborhood characteristics were not associated with insomnia. Conclusions: Shortened sleep related to adverse social environments represents one potential pathway through which neighborhoods may influence health. Citation: DeSantis AS; Diez Roux AV; Moore K; Baron KG; Mujahid MS; Nieto FJ. Associations of neighborhood characteristics with sleep timing and quality: the multi-ethnic study of atherosclerosis. SLEEP 2013;36(10):1543-1551. PMID:24082314

DeSantis, Amy S.; Diez Roux, Ana V.; Moore, Kari; Baron, Kelly G.; Mujahid, Mahasin S.; Nieto, F. Javier

2013-01-01

60

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

SciTech Connect

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

Talamo, Alberto, E-mail: alby@anl.gov [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)] [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)

2013-05-01

61

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

PubMed

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

Kim, Sang-Oh; Shelby, Bo

2008-04-01

62

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. PMID:22956865

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

2012-01-01

63

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

64

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. PMID:21818282

Liu, Jiming; Tao, Li; Xiao, Bo

2011-01-01

65

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

NASA Astrophysics Data System (ADS)

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

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

2002-05-01

66

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)

2013-07-01

67

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

68

Erosion characteristics of an erodible tablet incorporated in a time-delayed capsule device.  

PubMed

A time-delayed oral drug delivery device was investigated in which an erodible tablet (ET), sealing the mouth of an insoluble capsule, controlled the lag-time prior to drug release. The time-delayed capsule (TDC) lag-time may be altered by manipulation of the excipients used in the preparation of the ET. Erosion rates and drug release profiles from TDCs were investigated with four different excipient admixtures with lactose: calcium sulphate dihydrate (CSD), dicalcium phosphate (DCP), hydroxypropylmethyl cellulose (HPMC; Methocel K100LV grade) and silicified microcrystalline cellulose (SMCC; Prosolv 90 grade). Additionally, the compressibility of different insoluble coated capsules was tested at different moisture levels to determine their overall integrity and suitability for oral delivery. Erosion rates of CSD, DCP, and SMCC displayed a nonlinear relationship to their concentration, while HPMC indicated rapid first-order erosion followed by zero-order erosion, the onset of which was dependent on the HPMC concentration. Capsule integrity was confirmed to be most suitable for oral delivery when the insoluble ethyl cellulose coat was applied to a hard gelatin capsule using an organic spray coating process. T50% drug release times varied between 245 (+/-33.4) and 393 (+/-40.8) minutes for 8% and 20% DCP, respectively, T50% release times of 91 (+/-22.1) and 167 (+/-34.6) were observed for 8% and 20% CSD; both formulations showed incidence of premature drug release. The SMCC formulations showed high variability due to lamination effects. The HPMC formulations had T50% release times of 69 (+/-13.9), 213 (+/-25.4), and 325 (+/-30.3) minutes for 15%, 24%, and 30% HPMC concentrations respectively, with no premature drug release. In conclusion, HPMC showed the highest reproducibility for a range of time-delayed drug release from the assembled capsule formulation. The method of capsule coating was confirmed to be important by investigation of the overall capsule integrity at elevated humidity levels. The erosion characteristics of ETs containing HPMC may be described by gravimetric loss. The novel time-delayed capsule device presented in this study may be assembled to include an erodible tablet with a known concentration of HPMC. A variety of suitable drugs for targeted chronopharmaceutical therapy can be incorporated into such a device, ultimately improving drug efficacy and patient compliance, and reducing harmful side effects. PMID:15704859

McConville, Jason T; Ross, Alistair C; Florence, Alastair J; Stevens, Howard N E

2005-01-01

69

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

70

CCMR: Quantifying the Relationship Between Nanofiber Web Pore Characteristics and Electrospinning Time  

NSDL National Science Digital Library

Nonwoven, electrospun nanofibers have enjoyed increased research attention for many of their unique electrical, optical and mechanical properties; high surface to volume ratio; and ability to be designed to display a desired surface charge. In order to aid future research involving filtration and particle detection, the goal of this study was to quantify pore characteristics of polyvinyl alcohol (PVA) fabrics spun for low times. The two methods used were capillary flow porometry and scanning electron microscope image analysis. 8, 10 and 12 w% solutions of PVA with maleic anhydride (MA) and Polybrene additives for surface charge were spun at 0.01 mL/min with a 15 cm collecting distance and an applied charge of 12kV. The 10 w% for both solutions had better spinnability and fiber uniformity, although the PVA/MA had significantly greater fiber diameter uniformity over the PVA/Polybrene solution. The porometer returned a range of 30.9 ?m to 3.3 ?m and the image analysis a range of about 6 ?m to 1 ?m from 5 seconds to 5 minutes. Although capillary flow porometry cannot measure porosity, SEM image analysis found that the porosity of both solutions was reduced from 80% at 5 seconds to only 28% at 5 minutes. The uniformity of pores became apparent with roughly 1 minute of spinning time and increased with times greater than 1 minute.

Luginbuhl, Kelli M.

2010-08-15

71

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

NASA Astrophysics Data System (ADS)

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

Moghadam, Ali Jabari

2015-02-01

72

Working control system for space-time characteristics of industrial IR lasers  

SciTech Connect

This paper discusses the problem of monitoring emission parameters of lasers in industrial use. The principles of a system for working control and analysis of the space-time characteristics of these IR lasers are considered. The authors explain how the IR emission of a laser is applied to a beam splitter and the component is diverted to the aperture of a shaping optical system that transforms the radiation and separates the investigated radiation parameter. The IR radiation acting on the LS causes heating of the luminor excited by the source. The image on the LS is projected through an optical system that contains a filter opaque to the UV radiation. The output goes to a computing unit and are picked off the radiation-beam parameters needed for monitoring and control.

Dvoretskii, S.A.; Klyuchnikov, V.M.; Kuirikadze, D.G.; Pospelova, L.A.; Senashenko, M.V.; Zaitsev, L.M.

1986-01-01

73

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. PMID:24376656

Marín, Arturo; Tejero, Héctor; Nuño, Juan Carlos; Montero, Francisco

2013-01-01

74

The advantage of arriving first: characteristic times in finite size populations of error-prone replicators.  

PubMed

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. PMID:24376656

Marín, Arturo; Tejero, Héctor; Nuño, Juan Carlos; Montero, Francisco

2013-01-01

75

Flow characteristics of a pilot-scale high temperature, short time pasteurizer.  

PubMed

In this study, we present a method for determining the fastest moving particle (FMP) and residence time distribution (RTD) in a pilot-scale high temperature, short time (HTST) pasteurizer to ensure that laboratory or pilot-scale HTST apparatus meets the Pasteurized Milk Ordinance standards for pasteurization of milk and can be used for obtaining thermal inactivation data. The overall dimensions of the plate in the pasteurizer were 75 x 115 mm, with a thickness of 0.5 mm and effective diameter of 3.0 mm. The pasteurizer was equipped with nominal 21.5- and 52.2-s hold tubes, and flow capacity was variable from 0 to 20 L/h. Tracer studies were used to determine FMP times and RTD data to establish flow characteristics. Using brine milk as tracer, the FMP time for the short holding section was 18.6 s and for the long holding section was 36 s at 72 degrees C, compared with the nominal times of 21.5 and 52.2 s, respectively. The RTD study indicates that the short hold section was 45% back mixed and 55% plug flow for whole milk at 72 degrees C. The long hold section was 91% plug and 9% back mixed for whole milk at 72 degrees C. This study demonstrates that continuous laboratory and pilot-scale pasteurizers may be used to study inactivation of microorganisms only if the flow conditions in the holding tube are established for comparison with commercial HTST systems. PMID:15375033

Tomasula, P M; Kozempel, M F

2004-09-01

76

Time-frequency characteristics based motion estimation and imaging for high speed spinning targets via narrowband waveforms  

Microsoft Academic Search

This paper focuses on the motion parameters estimation and inversed synthetic aperture radar (ISAR) imaging for the high-speed\\u000a spinning targets via the time-frequency characteristics. Assuming that the translational motion is compensated with the available\\u000a motion compensation techniques, then the residual part of translational motion and the spinning motion are estimated with\\u000a high precision based on the time-frequency characteristics. Combining with

Lei Zhang; YaChao Li; Yan Liu; MengDao Xing; Zheng Bao

2010-01-01

77

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

78

Time-motion analysis, heart rate, and physiological characteristics of international canoe polo athletes.  

PubMed

To evaluate the time international canoe polo players spend performing various game activities, measure heart rate (HR) responses during games, and describe the physiological profile of elite players. Eight national canoe polo players were videotaped and wore HR monitors during 3 games at a World Championship and underwent fitness testing. The mean age, height, and weight were 25 ± 1 years, 1.82 ± 0.04 m, and 81.9 ± 10.9 kg, respectively. Time-motion analysis of 3 games indicated that the players spent 29 ± 3% of the game slow and moderate forward paddling, 28 ± 5% contesting, 27 ± 5% resting and gliding, 7 ± 1% turning, 5 ± 1% backward paddling, 2 ± 1% sprinting, and 2 ± 1% dribbling. Sixty-nine (±20)% of the game time was played at an HR intensity above the HR that corresponded to the ventilatory threshold (VT) that was determined during the peak V[Combining Dot Above]O2 test. Peak oxygen uptake and VT were 3.3 ± 0.3 and 2.2 ± 0.3 L·min, respectively, on a modified Monark arm crank ergometer. Arm crank peak 5-second anaerobic power was 379 W. The majority of the time spent during international canoe polo games involved slow-to-moderate forward paddling, contesting for the ball, and resting and gliding. Canoe polo games are played at a high intensity indicated by the HR responses, and the physiological characteristics suggest that these athletes had high levels of upper body aerobic and anaerobic fitness levels. PMID:23287835

Forbes, Scott C; Kennedy, Michael D; Bell, Gordon J

2013-10-01

79

Escape times for rigid Brownian rotators in a bistable potential from the time evolution of the Green function and the characteristic time of the probability evolution  

NASA Astrophysics Data System (ADS)

The greatest relaxation time for an assembly of three-dimensional rigid rotators in an axially symmetric bistable potential is obtained exactly in terms of continued fractions as a sum of the zero frequency decay functions (averages of the Legendre polynomials) of the system. This is accomplished by studying the entire time evolution of the Green function (transition probability) by expanding the time dependent distribution as a Fourier series and proceeding to the zero frequency limit of the Laplace transform of that distribution. The procedure is entirely analogous to the calculation of the characteristic time of the probability evolution (the integral of the configuration space probability density function with respect to the position co-ordinate) for a particle undergoing translational diffusion in a potential; a concept originally used by Malakhov and Pankratov (Physica A 229 (1996) 109). This procedure allowed them to obtain exact solutions of the Kramers one-dimensional translational escape rate problem for piecewise parabolic potentials. The solution was accomplished by posing the problem in terms of the appropriate Sturm-Liouville equation which could be solved in terms of the parabolic cylinder functions. The method (as applied to rotational problems and posed in terms of recurrence relations for the decay functions, i.e., the Brinkman approach c.f. Blomberg, Physica A 86 (1977) 49, as opposed to the Sturm-Liouville one) demonstrates clearly that the greatest relaxation time unlike the integral relaxation time which is governed by a single decay function (albeit coupled to all the others in non-linear fashion via the underlying recurrence relation) is governed by a sum of decay functions. The method is easily generalized to multidimensional state spaces by matrix continued fraction methods allowing one to treat non-axially symmetric potentials, where the distribution function is governed by two state variables.

Coffey, W. T.; Crothers, D. S. F.; Titov, S. V.

2001-09-01

80

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

81

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

NASA Astrophysics Data System (ADS)

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

Kim, Roksoon

2015-04-01

82

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

83

Consistent time-of-flight mobility measurements and polymer light-emitting diode current{endash}voltage characteristics  

SciTech Connect

We present time-of-flight mobility measurements and measured and calculated current{endash}voltage (I{endash}V) characteristics of structures fabricated using a soluble poly({ital p}-phenylene vinylene) derivative. Time-of-flight measurements were used to determine the electric field dependent hole mobility. This mobility was then used, without adjustable parameters, to calculate the I{endash}V characteristics of space-charge-limited, hole only devices. The measured and calculated I{endash}V characteristics are in good agreement over five orders of magnitude in current. These results demonstrate that an electric field dependent mobility, without invoking trapping effects, provides an accurate description of hole transport in this polymer. {copyright} {ital 1999 American Institute of Physics.}

Campbell, I.H.; Smith, D.L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Neef, C.J.; Ferraris, J.P. [The University of Texas at Dallas, Richardson, Texas 75083 (United States)] [The University of Texas at Dallas, Richardson, Texas 75083 (United States)

1999-05-01

84

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

85

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. PMID:20025395

Ram, Nilam; Gerstorf, Denis

2009-01-01

86

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

87

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

88

Predicting the unpredictable: A new prediction model for operating room times using individual characteristics and the surgeon's estimate  

Microsoft Academic Search

Background: Routine predictions made by surgeons or historical mean durations have only limited capacity to predict operating room (OR) time. The authors aimed to devise a prediction model using the surgeon's estimate and characteristics of the surgical team, the operation, and the patient. Methods: Seventeen thousand four hundred twelve consecutive, elective operations from the general surgical department in an academic

Marinus J. C. Eijkemans; Mark van Houdenhoven; Tien Nguyen; H. Boersma; Ewout W. Steyerberg; Geert Kazemier

2010-01-01

89

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

SciTech Connect

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

Paeng, Dongwoo; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu [Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720-1740 (United States); Lee, Daeho [Department of Mechanical Engineering, Gachon University, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of)

2014-08-18

90

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

91

Differentiating Blood, Lymph, and Primo Vessels by Residual Time Characteristic of Fluorescent Nanoparticles in a Tumor Model  

PubMed Central

Fluorescent nanoparticles (FNPs) which were injected into a tumor tissue flowed out through the blood and lymph vessels. The FNPs in blood vessels remained only in the order for few minutes while those in lymph vessels remained for a long time disappearing completely in 25 hours. We found a primo vessel inside a lymph vessel near a blood vessel, and FNPs remained in the primo vessel for longer than 25 hours. In addition, we examined in detail the residual time characteristics of lymph vessels because it could be useful in a future study of fluid dynamical comparison of the three conduits. These residual time characteristics of FNPs in the three kinds of vessels may have implications for the dynamics of nanoparticle drugs for cancer chemotherapy. PMID:23662147

Lee, Sungwoo; Lim, Jaekwan; Cha, Jinmyung; Lee, Jin-Kyu; Ryu, Yeon Hee; Kim, SungChul; Soh, Kwang-Sup

2013-01-01

92

Characteristics of Full-Time Public Community Junior College Instructors: The Kansas Profile.  

ERIC Educational Resources Information Center

A 10-page questionnaire was used to determine the characteristics of Kansas junior college personnel. The data collected were to provide a profile of the teachers and to be available in detail to anyone interested. The four categories of inquiry were: (1) biographical data on age, sex, marital status, residence, schooling, education and occupation…

Parker, Paul

93

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

94

Peritoneal transport characteristics and dwelling time significantly impact ghrelin clearance in peritoneal dialysis patients  

Microsoft Academic Search

Background. Plasma ghrelin exerts widespread bioactivities. Although it is effectively removed from the blood by a single course of haemodialysis, peritoneal clearance of ghrelin is uncertain. Our study aimed to determine (i) whether there is a correlation between plasma ghrelin levels and characteristics of peritoneal ghrelin clearance, and (ii) whether plasma ghrelin levels significantly impact markers of mortality or morbidity

Chia-Chu Chang; Ching-Hui Hung; Hung-Lin Chen; Kai-Lin Hwang; Ching-Yuang Lin

2006-01-01

95

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

ERIC Educational Resources Information Center

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

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

2012-01-01

96

Professional Characteristics and Job Satisfaction Among SGIM Members: A Comparison of Part-time and Full-time Physician Members  

Microsoft Academic Search

BACKGROUND  As more physicians work part-time (PT), the faculty, institutions, and organizations that represent them should understand\\u000a the factors that motivate and satisfy these physicians.\\u000a \\u000a \\u000a \\u000a OBJECTIVE  Compare factors associated with job satisfaction among PT and full-time (FT) academic physicians.\\u000a \\u000a \\u000a \\u000a DESIGN  Cross-sectional survey.\\u000a \\u000a \\u000a \\u000a PARTICIPANTS  Members of the Society of General Internal Medicine (SGIM), a national, academic Internal Medicine organization.\\u000a \\u000a \\u000a \\u000a RESULTS  Fifty percent (1,396 of 2,772) of

Rachel B. Levine; Rebecca A. Harrison; Hilit F. Mechaber; Christopher Phillips; Thomas H. Gallagher

2008-01-01

97

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

98

Performance characteristics of a microwave plasma disk ion source. [time varying electric propulsion concept  

NASA Technical Reports Server (NTRS)

The development, design, and preliminary performance characteristics of a microwave plasma disk ion source are presented. Several important design concepts indigenous to microwave plasmas have been utilized in the development of this ion source: generation of a resonantly sustained microwave discharge inside a microwave/plasma coupler, probe and length tuning of the microwave/plasma coupler, and minimization of plasma volume. The experimental results for a 2.45 GHz, eight cm ion source excited in the TE(211) and TM(011) modes are described. Results are presented for electromagnetic mode excitation, electron density, coupling efficiency and loaded cavity Q, and I-V characteristics and efficiencies. It is preliminarily shown that a microwave disk-like plasma can be sustained adjacent to the grids with either TE or TM cavity modes at pressures below 2 x 10 to the -4th torr. Over 80% of the power absorbed in the cavity is coupled into the plasma.

Asmussen, J.; Root, J.; Nakanishi, S.

1982-01-01

99

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

100

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

101

Space - time diaries and travel characteristics for different levels of respondent aggregation  

Microsoft Academic Search

Significant progress has been made in the analysis of space - time diary data. Drawing on the flexibility that such data provide, in this study the authors group respondents at five different levels of aggregation, and compare them according to their mean and standard deviation values for selected measures of travel behaviour. The measures, derived from the time - geography

D G Janelle; M F Goodchild; B Klinkenberg

1988-01-01

102

Time-dependent current-voltage characteristics of Al/p-CdTe/Pt x-ray detectors  

NASA Astrophysics Data System (ADS)

Current-voltage (I-V) characteristics of Schottky Al/p-CdTe/Pt detectors were investigated in dark and at different temperatures. CdTe detectors with Al rectifying contacts, very appealing for high resolution x-ray and gamma ray spectroscopy, suffer from bias-induced polarization phenomena which cause current increasing with the time and severe worsening of the spectroscopic performance. In this work, we studied the time-dependence of the I-V characteristics of the detectors, both in reverse and forward bias, taking into account the polarization effects. The I-V measurements, performed at different time intervals between the application of the bias voltage and the measurement of the current, and the measured current transients show as the electrical instability manifests itself even in time intervals shorter (i.e., <1 s) than those are necessary to make evident the degradation of the spectroscopic properties. The results point out as this time interval is a critical parameter for correct investigations on the electrical properties of these devices. Although the detectors are typically classified as Schottky-type detectors, we find that the thermionic emission is not the dominant transport mechanism, except at very low bias voltage values. Finally, the Schottky barrier height of the Al/p-CdTe contact was extracted by measuring the contact resistance at zero bias.

Principato, F.; Gerardi, G.; Turturici, A. A.; Abbene, L.

2012-11-01

103

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

104

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

PubMed

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

Demirel, S; Kirikçi, K

2009-02-01

105

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

106

Time domain characteristics of human force control in rejection of transient disturbances during movement  

E-print Network

Many tasks that humans successfully complete are more naturally represented in terms of their force requirements than their state (position or velocity) requirements. Yet the literature on force and timing is relatively ...

Maneri, Erin, 1977-

2004-01-01

107

Selective influence of circadian modulation and task characteristics on motor imagery time.  

PubMed

In this study, we examined the effect of circadian modulation on motor imagery (MI) time while also considering the effects of task complexity and duration. The ability to imagine in real time was influenced by circadian modulation in a simple walking condition, with longer MI times in the morning and evening sessions. By contrast, there was no effect of circadian rhythm in the complex, short or long walking conditions. We concluded that motor imagery time is modulated during the course of the day, but the effect of task difficulty is stronger than circadian modulation in altering the temporal congruence between physical practice and MI performance. Practical applications in motor learning and rehabilitation are discussed. PMID:22978194

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

2012-09-01

108

Characteristic-based algorithms for solving the Maxwell equations in the time domain  

Microsoft Academic Search

Several numerical algorithms, developed in the computational-fluid-dynamics community for solving the Euler equations, are found to be equally effective for solving the Maxwell equations in the time domain. The basic approach of these numerical procedures is to achieve the Riemann approximation to the time-dependent, three-dimensional problem in each spatial direction. The three-dimensional equations are then solved by a sequence of

J. S. Slrang; Wright-Patterson AFB

1995-01-01

109

Computing Quantitative Characteristics of Finite-State Real-Time Systems  

Microsoft Academic Search

This paper presents a general method for computing quantitative information about finite-state real-time sys- tems. We have developed algorithms that compute exact bounds on the delay between two speci$ed events and on the number of occurrences of an event in a given inter- val. This technique allows us to determine performance measures such as schedulability response time, and system load.

Sérgio Vale Aguiar Campos; Edmund M. Clarke; Wilfredo R. Marrero; Marius Minea; Hiromi Hiraishi

1994-01-01

110

Relationships among display features, eye movement characteristics, and reaction time in visual search.  

PubMed

The relative contribution of number of fixations and fixation duration to reaction time in visual search was investigated. Ten participants (age 20-24 years) took part in each of two experiments. In Experiment 1, the experimental factors were display type (icon and file name), organization (arrangements with and without grouping), and number of stimuli presented (4, 8, and 16). In Experiment 2, a search task for a target stimulus (three prespecified random letters) was conducted, and the experimental factor was the display's layout complexity. Multiple regression analysis was used to examine whether reaction time was explained by a mediational model in which reaction time is mediated by eye movements and display features are not directly related to reaction time. The mediational model was not supported, and the effects of display features on reaction time were not attributable solely to eye movements. The interaction between number of fixations and fixation duration was also explored as a function of display features. As the display feature changed and the task became more difficult, the contribution of the number of fixations to explain the variation in reaction time became dominant for both experiments. Potential applications include measurements of cognitive ability, eye muscle balance disorders, and binocular fusion ability. PMID:16435700

Murata, Atsuo; Furukawa, Nobuyasu

2005-01-01

111

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

SciTech Connect

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

Rondorf, Dennis W.; Beeman, John W.; Free, Mary E. (Seattle National Fishery Research Center, Columbia River Field Station, Cook, WA)

1988-06-01

112

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. PMID:24982908

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

113

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

114

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

115

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

SciTech Connect

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

Kwok, K.S.

1993-11-12

116

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

SciTech Connect

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

Mohamed, Norani Muti, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: pervaiz-pas@yahoo.com, E-mail: shuaib-penang@yahoo.com, E-mail: zainabh@petronas.com.my; Ahmad, Pervaiz, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: pervaiz-pas@yahoo.com, E-mail: shuaib-penang@yahoo.com, E-mail: zainabh@petronas.com.my; Saheed, Mohamed Shuaib Mohamed, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: pervaiz-pas@yahoo.com, E-mail: shuaib-penang@yahoo.com, E-mail: zainabh@petronas.com.my; Burhanudin, Zainal Arif, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: pervaiz-pas@yahoo.com, E-mail: shuaib-penang@yahoo.com, E-mail: zainabh@petronas.com.my [Center of Innovative Nanostructures and Nanodevices (COINN), Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Tronoh, Perak (Malaysia)

2014-10-24

117

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

118

Gender differences in social network characteristics and psychological well-being among Hong Kong Chinese: The role of future time perspective and adherence to Renqing  

Microsoft Academic Search

Gender differences in social network characteristics are well documented in the literature. Socioemotional selectivity theory emphasizes the importance of future time perception on selection of social partners whereas cultural studies stress the roles of Renqing (relationship orientation) on social interactions. This study examined the effects of future time perspective and adherence to Renqing on social network characteristics, and their associations

D. Y. Yeung; H. H. Fung; F. R. Lang

2007-01-01

119

Laminar, Turbulent, and Inertial Shear-Thickening Regimes in Channel Flow of Neutrally Buoyant Particle Suspensions  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

120

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

121

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

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

122

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

Microsoft Academic Search

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)

G. J. Walker

1993-01-01

123

DNS of laminar-turbulent boundary layer transition induced by solid obstacles  

E-print Network

Results of numerical simulations obtained by a staggered finite difference scheme together with an efficient immersed boundary method are presented to understand the effects of the shape of three-dimensional obstacles on the transition of a boundary layer from a laminar to a turbulent regime. Fully resolved Direct Numerical Simulations (DNS), highlight that the closer to the obstacle the symmetry is disrupted the smaller is the transitional Reynolds number. It has been also found that the transition can not be related to the critical roughness Reynolds number used in the past. The simulations highlight the differences between wake and inflectional instabilities, proving that two-dimensional tripping devices are more efficient in promoting the transition. Simulations at high Reynolds number demonstrate that the reproduction of a real experiment with a solid obstacle at the inlet is an efficient tool to generate numerical data bases for understanding the physics of boundary layers. The quality of the numerical ...

Orlandi, Paolo; Bernardini, Matteo

2015-01-01

124

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

125

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

PubMed

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

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

2014-12-19

126

Time and Difficulty with Tasks and Illness Characteristics Among Caregivers of Individuals Receiving Daily Home Hemodialysis  

E-print Network

Receiving Daily Home Hemodialysis Hannah B. Henderson, Janet L. Welch Indiana University School of Nursing and co- morbidities, and level of involvement of home dialysis staff. Mentor: Janet L.Welch, School be associated with time and difficulty of tasks experienced by caregivers of individuals receiving daily home

Zhou, Yaoqi

127

Characteristics of Disfluency Clusters over Time in Preschool Children Who Stutter  

ERIC Educational Resources Information Center

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

Sawyer, Jean; Yairi, Ehud

2010-01-01

128

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

129

Plasma characteristics of vacuum arc ion source by using time-of-flight mass spectrometry  

Microsoft Academic Search

Vacuum arc ion sources can be used to ionize both gases and solid substance. When the electrodes of the vacuum arc source are made of a metallic hydride, the hydrogen can be desorbed and ionized when vacuum arc is discharged. In this paper, the mass and velocity of ions in a pulsed vacuum arc plasma source were measured by time-of-flight

L. Cheng; L. Chen; D. Z. Jin; W. Xiang; X. H. Tan

2010-01-01

130

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

ERIC Educational Resources Information Center

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

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

2009-01-01

131

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

ERIC Educational Resources Information Center

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

Kitano, Katsunori; Fukai, Tomoki

2004-01-01

132

Performance study of a DWDM link with real-time characteristics  

Microsoft Academic Search

The Dense Wavelength Division Multiplexing is an optical technology which allows transmitting across a fiber many wavelengths, which can be added and dropped by means of passive optical components. A plugin link module, capable of building full duplex nodes in the Gb\\/s domain for systems with real-time requirements, is presented in this paper. To debug and characterize the link, the

Alberto Aloisio; R. Giordano; V. Izzo; F. Ameli; G. Giovanetti

2009-01-01

133

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

134

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. We benchmark the method of characteristics against several popular modal approaches. Two of these, which we refer to as the concentrated body force method (CBFM) and the homogeneous eigenfunction expansion method (HEEM), were developed to simplify the well-established but tedious Mindlin-Goodman method. To homogenize the boundary conditions and enable modal analysis, the CBFM and HEEM forgo the usual formalism of linear transformations (à la Mindlin-Goodman) in favor of intuitive modeling assumptions and postulated solution structures. We find, however, that these approaches introduce an artificial stress discontinuity at the forced boundary in their reformulated problems. When these reformulated problems are solved by modal analysis, spurious oscillations and significant overshoot, similar to the Gibbs phenomenon, emerge in the stress profile at the artificial discontinuity. We demonstrate that these oscillations and overshoot are physical manifestations of a series solution for stress, obtained from term-by-term differentiation, that is not uniformly convergent, as required by the formalism of mathematical analysis. The method of characteristics solution, on the other hand, is exact to within machine precision, yielding no artificial discontinuities, spurious oscillations, or unphysical overshoot. Unlike the modal approaches, the method of characteristics solves the first-order problem with time-dependent boundary conditions ‘as is' without any reformulation, restructuring, or postulated solution structures. Further, its solutions require no post-processing: no a posteriori solution treatment like l'Hôpital's rule to accommodate resonance (resonant behavior is inherently captured without the emergence of singularities), no term-by-term differentiation to deduce stress (stress is primitive in a first-order velocity-stress formulation of elastodynamics), and no convergence tests.

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

2014-02-01

135

Characteristics of a real time monitor using the interference enhanced reflection method for organic vapors.  

PubMed

Performance and sensor characteristics of a monitor for volatile organic compounds (VOC monitor) using the interference enhanced reflection (IER) method were investigated for 52 organic solvent vapors that are designated as class 1 and class 2 organic solvents by the Ordinance of Organic Solvent Poisoning Prevention in Japan. Test vapors were prepared by injecting 1 to 3 ?l of liquid solvent into a 20 l Tedlar(®) bag and perfectly vaporizing them. The vapor concentration was simultaneously measured with the monitor and a gas chromatograph (GC) equipped with flame ionization detector, and both values were compared. The monitor could detect all the solvent vapors that we used. Linear response was obtained between the concentration measured by the monitor and those by the GC. The monitor could detect 1/10 of the administrative control level for 37 of 52 solvent vapors, including toluene and xylenes. For 15 vapors, on the other hand, the monitor could not be used for the working environment measurement because the sensor response was low or the regression lines did not pass through the origin. PMID:24334693

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

2013-12-01

136

[Real-time UV imaging of chloramphenicol intrinsic dissolution characteristics from ophthalmic in situ gel].  

PubMed

In this paper, chloramphenicol was selected as a model drug to prepare in situ gels. The intrinsic dissolution rate of chloramphenicol from in situ gel was evaluated using the surface dissolution imaging system. The results indicated that intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel decreased significantly when the poloxamer concentration increased. The addition of the thickener reduced the intrinsic dissolution rate of chloramphenicol thermosensitive gel, wherein carbomer had the most impact. Different dilution ratios of simulated tear fluid greatly affected gel temperature, and had little influence on the intrinsic dissolution rate of chloramphenicol from the thermosensitive in situ gel. The pH of simulated tear fluid had little influence on the intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel. For the pH sensitive in situ gel, the dissolution rates of chloramphenicol in weak acidic and neutral simulated tear fluids were slower than that in weak alkaline simulated tear fluid. In conclusion, the intrinsic dissolution of chloramphenicol from in situ gel was dependent on formulation and physiological factors. With advantages of small volume sample required and rapid detection, the UV imaging method can be an efficient tool for the evaluation of drug release characteristics of ophthalmic in situ gel. PMID:24133985

Chen, Jian-Xiu; Guo, Zhen; Li, Hai-Yan; Wu, Li; He, Zhong-Gui; Hu, Rong-Feng; Zhang, Ji-Wen

2013-07-01

137

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

PubMed

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

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

2011-12-01

138

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

139

Taekwondo techniques and competition characteristics involved in time-loss injuries  

Microsoft Academic Search

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

Konstantinos Beis; Willy Pieter; George Abatzides

140

The effects of corridor characteristics on motorists' decisions to divert in resonse to time saving messages  

E-print Network

OP FIGURES Page Study Area, Central Section of the North Central Expressway Corridor 14 Southbound Travel Times on North Central Expressway from Lyndon B. Johnson Freeway Exit to the Central Business District . 29 Percentage of Diversion... agencies and jurisdictions. ATMS also provides the necessary infrastructure for all IVHS cotnponents such as the communication network, control center hardware and software, and operation and maintenance activities. Advanced Traveler Information Systems...

Robbins, Charles John

1993-01-01

141

Flow Characteristics of a Pilot-Scale High Temperature, Short Time Pasteurizer  

Microsoft Academic Search

In this study, we present a method for determining the fastest moving particle (FMP) and residence time distribution (RTD) in a pilot-scale high temperature, shorttime(HTST)pasteurizertoensurethatlaboratory or pilot-scale HTST apparatus meets the Pasteurized Milk Ordinance standards for pasteurization of milk andcanbeusedforobtainingthermalinactivationdata. The overall dimensions of the plate in the pasteurizer were 75 × 115 mm, with a thickness of 0.5 mm

P. M. Tomasula; M. F. Kozempel

2004-01-01

142

Characteristics of the near-Earth magnetotail variations at the time of substorm onset  

NASA Astrophysics Data System (ADS)

From the result of our statistical analysis with GEOTAIL and THEMIS data, we confirmed that tailward plasma flows are created in association with the plasma flows that propagate from X ~ -12 Re toward the earth at the time of substorm onset. To understand the physical mechanism of the formation of such tailward flows, we have performed a case study of substorm event occurred at 10:46 UT on June 22, 1997 when the GEOTAIL was located at (X, Y) ~ (-9, 6) Re and encountered with the flow bursts. The event started with earthward flows for about 2 min with the northward magnetic field enhancement, followed by slow tailward flows. Such an earthward and tailward flow sequence repeated three times. By calculating the electric current from electron and ion moment data, we found the variation in the X-component of JxB force that can be interpreted to have close relationship with the enhancement of earthward flows. Namely, the flows are not simply generated at a distant location and reach the GEOTAIL, but they are still under acceleration at X ~ -10 Re. After the passage of the flow front, the (JxB)x term takes negative values. The time derivative of Vx does not necessarily correspond to (JxB)x/mn. This inconsistency might be due to the contribution of the terms such as -grad P or (Vgrad) V. It is also necessary to check the possibility of the decoupling between electrons and ions as well as the effect of anomalous resistivity.

Machida, S.; Miyashita, Y.; Ieda, A.; Saito, Y.

2013-12-01

143

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

PubMed

Early detection of cancer is crucial for the successful diagnostics of its presence and its subsequent treatment. To improve cancer detection, we tested the progressive multimodal optical imaging of U87MG cells in culture. A combination of steady-state spectroscopic methods with the time-resolved approach provides a new insight into the native metabolism when focused on endogenous tissue fluorescence. In this contribution, we evaluated the metabolic state of living U87MG cancer cells in culture by means of endogenous flavin fluorescence. Confocal microscopy and time-resolved fluorescence imaging were employed to gather spectrally and time-resolved images of the flavin fluorescence. We observed that flavin fluorescence in U87MG cells was predominantly localized outside the cell nucleus in mitochondria, while exhibiting a spectral maximum under 500 nm and fluorescence lifetimes under 1.4 ns, suggesting the presence of bound flavins. In some cells, flavin fluorescence was also detected inside the cell nuclei in the nucleoli, exhibiting longer fluorescence lifetimes and a red-shifted spectral maximum, pointing to the presence of free flavin. Extra-nuclear flavin fluorescence was diminished by 2-deoxyglucose, but failed to increase with 2,4-dinitrophenol, the uncoupler of oxidative phosphorylation, indicating that the cells use glycolysis, rather than oxidative phosphorylation for functioning. These gathered data are the first step toward monitoring the metabolic state of U87MG cancer cells. PMID:25521208

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

2015-05-01

144

Extracting Concrete Thermal Characteristics from Temperature Time History of RC Column Exposed to Standard Fire  

PubMed Central

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

2014-01-01

145

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

NASA Astrophysics Data System (ADS)

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

Du, Yong; Liu, Jianjun; Hong, Zhi

2013-08-01

146

Space-Time Characteristics of Light Transmitted through Dense Clouds: A Green's Function Analysis.  

NASA Astrophysics Data System (ADS)

Here, previous work using photon diffusion theory to describe radiative transfer through dense plane-parallel clouds at nonabsorbing wavelengths is extended. The focus is on the scaling of space- and time-domain moments for transmitted light with respect to cloud thickness H and optical depth ; and the new results are as follows: accurate prefactors for asymptotic scaling, preasymptotic correction terms in closed form, 3D effects for internal variability in , and the rms transit time or pathlength. Mean pathlength is H for dimensional reasons and, from random-walk theory, we already know that it is also (1 - g) for large enough (g being the asymmetry factor). Here, it is shown that the prefactor is precisely 1/2 and that corrections are significant for (1 - g) < 10, which includes most actual boundary layer clouds. It is also shown that rms pathlength is not much larger than the mean for transmittance (its prefactor is 0.59); this proves that, in sharp contrast with reflection, pathlength distributions are quite narrow in transmission. If the light originates from a steady point source on a cloud boundary, a fuzzy spot is observed on the opposite boundary. This problem is formally mapped to the pulsed source problem, and it is shown that the rms radius of this spot slowly approaches H as increases; it is also shown that the transmitted spot shape has a flat top and an exponential tail. Because all preasymptotic corrections are computed here, the diffusion results are accurate when compared to Monte Carlo counterparts for 5, whereas the classic scaling relations apply only for 70, assuming g = 0.85. The temporal quantities shed light on observed absorption properties and optical lightning waveforms. The spatial quantity controls the three-dimensional radiative smoothing process in transmission, which was recently observed in spectral analyses of time series of zenith radiance at 725 nm. Opportunities in ground-based cloud remote sensing using the new developments are described and illustrated with simulations of 3D solar radiative transfer in realistic models of stratocumulus. Finally, since this analytical diffusion study applies only to weakly variable stratus layers, extensions to more complex cloud systems using anomalous diffusion theory are discussed.

Davis, Anthony B.; Marshak, Alexander

2002-09-01

147

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

148

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

2012-03-01

149

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

150

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

PubMed Central

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

Rankin, Tauna L.; Sponaugle, Su

2014-01-01

151

Signal characteristics in coordinate time series of GPS-DORIS co-located stations  

NASA Astrophysics Data System (ADS)

Weekly time series of coordinate residuals are analysed using the wavelet transform in order to investigate the signal of the nonlinear station motion of 14 GPS-DORIS (Global Positioning System-Doppler Orbitography and Radiopositioning Integrated by Satellite) co-located stations over 2006.0 - 2011.8. The data used were computed by IGN/JPL (Institut Géographique National, France/ Jet Propulsion Laboratory, USA) using the GIPSY-OASIS II software package, referred to ITRF2005 and expressed in the local geodetic reference frame. The Multi-resolution analysis has assessed well the nonlinear trends and the seasonal signals in the studied time series. The horizontal displacements (North and East) of the stations are mainly associated to the plate tectonics and the vertical displacements are associated to the local subsidence or postglacial rebound. However, the error due to the period of 118 days was not hopefully removed in the ign09wd01 solution for the totality of DORIS stations. Using the VisuShrink method with soft thresholding, the obtained results show that the DORIS positions are more distorted than those of GPS. Indeed, the standard deviation of the noise in respectively North, East and Vertical components is in the range of 1-2, 0.5-1 and 2-4 mm for GPS and 6-11, 5-17 and 6-15 mm for DORIS. For DORIS positions, the noise level in the East component is more important compared to the North and the Vertical ones and it is small in the stations at high latitude relatively to the other ones. Keywords: DORIS; GPS; Station coordinates; Wavelets; Multi-resolution analysis; De-noising.

Khelifa, S.; Kahlouche, S.; Faouzi Belbachir, M.

2012-04-01

152

Characteristics of settling coral reef fish are related to recruitment timing and success.  

PubMed

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

Rankin, Tauna L; Sponaugle, Su

2014-01-01

153

Long-characteristics methods with piecewise linear sources in space and time for transport on unstructured grids  

NASA Astrophysics Data System (ADS)

The method of characteristics (MOC) is a deterministic transport method that has been applied to large-scale problems including those in reactor physics and radiative transfer. Long characteristics, (LC) methods, have been used extensively to discretize and solve transport problems in the spatial domain. There is a need for an equally adequate time-dependent discretization for these transport problems. The new contributions from this research include the development of a space-time long characteristic (STLC) method with various source approximations including several that employ a piece-wise linear (PWL) approximation spatially. In the prism- PWL (PPWL) method the coefficient of each PWL spatial function is linear in time in each space-time cell. Along with STLC, a PWL-LC method is developed for steady-state problems in (x, y) and ( x, y, z). The methods developed in this work use least-squares projections to determine the coefficients of their source approximations. This work presents a detailed asymptotic analysis of the PWL-LC and STLC methods in the thick diffusion limit, which is of special interest in radiative transfer problems. This is the first such analysis reported for LC methods and these new methods are the first that are expected to perform well in this limit. Results from test problems executed with a modified version of the Parallel Deterministic Transport code, PDT, show the PWL-LC and STLC methods are more accurate than current methods for streaming problems. From asymptotic analysis and test problems, it is found that the steady-state PWL-LC method is accurate in the thick diffusion limit with solutions similar to those of analogous discontinuous finite element method, DFEM, solutions. Similarly, the PPWL-STLC method is found to be accurate in time-dependent thick diffusive problems. STLC is also a promising method for massively parallel applications because it permits the use of track-based sweeping, which appears to have significant advantages over cell-based sweeping. This is a key topic recommended for further research.

Pandya, Tara Marie

154

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

155

Time evolution of the general characteristics and Cu retention capacity in an acid soil amended with a bentonite winery waste.  

PubMed

The effect of bentonite waste added to a "poor" soil on its general characteristic and copper adsorption capacity was assessed. The soil was amended with different bentonite waste concentrations (0, 10, 20, 40 and 80 Mg ha(-1)) in laboratory pots, and different times of incubation of samples were tested (one day and one, four and eight months). The addition of bentonite waste increased the pH, organic matter content and phosphorus and potassium concentrations in the soil, being stable for P and K, whereas the organic matter decreased with time. Additionally, the copper sorption capacity of the soil and the energy of the Cu bonds increased with bentonite waste additions. However, the use of this type of waste in soil presented important drawbacks for waste dosages higher than 20 Mg ha(-1), such as an excessive increase of the soil pH and an increase of copper in the soil solution. PMID:25560662

Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

2015-03-01

156

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

SciTech Connect

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

Paulino, Arnold C., E-mail: apaulino@tmhs.or [Department of Radiology, Section of Radiation Oncology, Baylor College of Medicine, Houston, TX (United States); Ahmed, Irfan M.; Mai, Wei Y.; Teh, Bin S. [Department of Radiology, Section of Radiation Oncology, Baylor College of Medicine, Houston, TX (United States)

2009-12-01

157

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

158

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

USGS Publications Warehouse

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

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

2011-01-01

159

[Measurements of the ignition delay times of n-heptane by using characteristic emission from OH radical].  

PubMed

Using a measurement system consisting of a monochromator, a photomultiplier tube (PMT), piezoelectric pressure sensors and a digital oscilloscope, the ignition delay times of n-heptane/O2 mixture were measured behind reflected shock waves in a chemical shock tube, the onset of ignition was indicated by the steepest rise of the characteristic emission from OH radical at 306.4 nm. The experimental conditions cover temperatures from 1 170 to 1 730 K, pressures at (1.0 +/- 0.1) and (0.75 +/- 0.05) atm, and equivalence ratio of 1.0. Under these experimental conditions, the correlation formulas of ignition delay time dependence on the temperature for n-heptane have been obtained. Present results indicate that the ignition delay times of n-heptane decreases exponentially with the increase in temperatures. While temperature increases, the change rate of ignition delay time of n-heptane under the pressure of 0.75 atm is less than that of 1.0 atm. Present ignition delay data are important for constructing the kinetic model of the combustion reaction and provide an experimental criterion for validating the combustion reaction mechanism of n-heptane. PMID:21510410

Xie, Wei; Li, Ping; Zhang, Chang-Hua; Niu, Na; Nie, Xiao-Fei; Li, Cong-Shan

2011-02-01

160

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. PMID:25034216

2014-01-01

161

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

Microsoft Academic Search

Hepatic microsomal enzyme activity was induced in wild-trapped raccoons (Procyon lotor) and selected blood characteristics were measured in an effort to detect responses due to PCB ingestion, nutritional restriction, and their interactions. Barbiturate-induced sleeping times were used as an index of hepatic microsomal activity because they have been used reliably by other workers. Blood characteristics examined in the study were

W. Edward Montz; William C. Card; Roy L. Kirkpatrick

1982-01-01

162

Characteristics of pupillo-accommodative functions according to time of onset, gender and age in tonic pupil  

PubMed Central

AIM To evaluate the characteristics of pupillo-accommodative functions in patients with idiopathic tonic pupil according to the time of onset, gender, and age. METHODS Totally, 15 males and 19 females were divided into 2 groups depending on the time of disease onset: group I (onset <2 months, n=20) and group II (onset >2 months, n=14). A supersensivity test was conducted by applying diluted pilocarpine 0.125% to the eye and accommodative functions were evaluated using the near-point of accommodation (NPA) as the cutoff point, at which the patient experienced blurred vision. Pupil size and the ratio of decrease in the affected pupil after instillation of 0.125% pilocarpine were investigated. RESULTS There was no significant difference between the 2 groups regarding the various pupillary reflex results, including data on the affected pupil size before and after 0.125% pilocarpine, anisocoria, and ratio of pupil decrease. No significant difference in NPA was found between the 2 groups. However, female patients were noted to have greater anisocoria and a faster constriction ratio than those of the male patients (P=0.02 and P=0.04). On subgroup analysis, female patients from group II had larger affected-pupil sizes before 0.125% pilocarpine instillation and longer NPAs than those of the male patients. CONCLUSION No relationship was found between time of onset and dysfunction of pupillo-accommodative functions. Pupillo-accommodative functions and age were not related, except for the NPA. PMID:24195044

Koh, Kyung-Min; Kim, Ungsoo Samuel

2013-01-01

163

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

164

Effects of ramp slope on physiological characteristic and performance time of healthy adults propelling and pushing wheelchairs  

PubMed Central

[Purpose] This study examined the effects of ramp slope (1:12, 1:10, 1:8, and 1:6) on physiological characteristics and performance times of wheelchair users and the performance times of caregivers to determine which slope would be the best for wheelchairs, in order to propose a ramp slope that incorporates a universal design. [Subjects and Methods] Twenty-four healthy subjects were enrolled in this study. Fifteen of these subjects also volunteered to participate as caregivers. A wooden ramp with an adjustable slope was constructed. As manual wheelchair users, the participants performed propulsion of a wheelchair up the ramp at a self-selected pace. Four ramp slopes (1:12, 1:10, 1:8, and 1:6) were used, and the participants sequentially ascended them in order from the gentlest to the steepest slope. The caregivers also pushed a wheelchair up the ramp at a self-selected pace. The blood pressure and pulse of participants after the ascent, as well as the performance times of the caregivers and manual wheelchair users, were measured on each of the different ramp slopes. The measured data, pulse, blood pressure, and performance time, were analyzed using repeated ANOVA. [Results] Systolic blood pressure was significantly higher after ascending the 1:6 slope than after ascending the 1:12 and 1:8 slopes. Diastolic blood pressure was significantly higher after ascending the 1:6 slope than after ascending the 1:12 and 1:8 slopes. The participants’ pulses tended to increase significantly with an increase in slope. An assessment of the propulsion performance times revealed significant differences among the slopes. [Conclusion] Considering the results of the wheelchair users and caregivers, the 1:12 and 1:10 slopes are suitable ramp slopes for wheelchairs. PMID:25642025

Choi, Young Oh; Lee, Ho Young; Lee, Myoung Hee; Kwon, Oh Hyun

2015-01-01

165

A bottom-up approach: using residence time distributions and characteristic biogeochemical timescales to upscale multiphysics models of hyporheic exchange  

NASA Astrophysics Data System (ADS)

Residence time distributions (RTDs) and characteristic biogeochemical time scales (CBTSs) are integrated metrics that can be used to describe the biogeochemical evolution of water within hydrologic systems. RTDs describe the time that water and solutes are in contact with the system and strongly depend on the forcing and geomorphic features driving exchange and the system's hydraulic properties. On the other hand, CBTSs describe the time necessary for a biogeochemical transformation to take place and depend on the reaction type, solute concentrations entering the system, and chemical kinetics (or thermodynamics). Comparing RTDs and CBTSs allow us to evaluate the potential for transformation within the hydrologic system. In this work, we illustrate this approach with sinuosity-driven hyporheic zones; however, these concepts can be applied to other hydrologic systems. A two-dimensional, transient, numerical flow and transport model is used to illustrate the effect that dynamics, caused by deterministically generated flood events, has on flow fields and RTDs, and therefore on the character of the hyporheic zone as a biogeochemical reactor. A simple analytical model is used to estimate the CBTSs associated to the degradation of dissolved organic carbon in these hydrologic systems, which are compared to numerically-modeled RTDs and used to estimate the biogeochemical zonation within the HZ and its net biogeochemical response. Additionally, we use a multispecies, reactive transport model to assess this approach, paying special attention to those portions of the system with intermittent hyporheic contributions. In particular, transient flow results in time-varying hot-spot for biogeochemical reactions and induces the emergence of new modes on the dynamic RTDs, which are observed within the system and at the outlet. This parsimonious approach can be used as a predictive tool to quantify the potential of meanders as biogeochemical reactors at the watershed scale with the aid of historic discharge data, remote sensing data, and GIS processing techniques.

Gomez, Jesus D.; Wilson, John L.

2013-04-01

166

Early and long-term outcome of rehabilitation in stroke patients: The role of patient characteristics, time of initiation, and duration of interventions  

Microsoft Academic Search

Musicco M, Emberti L, Nappi G, Caltagirone C, for the Italian Multicenter Study on Outcomes of Rehabilitation of Neurological Patients. Early and long-term outcome of rehabilitation in stroke patients: the role of patient characteristics, time of initiation, and duration of interventions. Arch Phys Med Rehabil 2003;84:551-8. Objective: To determine whether and how patient characteristics and the time of initiation and

Massimo Musicco; Leonardo Emberti; Giuseppe Nappi; Carlo Caltagirone

2003-01-01

167

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

168

Long-Characteristics Methods with Piecewise Linear Sources in Space and Time for Transport on Unstructured Grids  

E-print Network

The method of characteristics (MOC) is a deterministic transport method that has been applied to large-scale problems including those in reactor physics and radiative transfer. Long characteristics, (LC) methods, have been used extensively...

Pandya, Tara M 1984-

2012-10-23

169

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

NASA Astrophysics Data System (ADS)

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

Guerra, Melania

170

Time and frequency requirement for the earth and ocean physics applications program. [characteristics and orbital mechanics of artificial satellites for data acquisition  

NASA Technical Reports Server (NTRS)

The application of time and frequency standards to the Earth and Ocean Physics Applications Program (EOPAP) is discussed. The goals and experiments of the EOPAP are described. Methods for obtaining frequency stability and time synchronization are analyzed. The orbits, trajectories, and characteristics of the satellites used in the program are reported.

Vonbun, F. O.

1972-01-01

171

A study of Time\\/Current Characteristics of the Ignition Processes in Cellulosic Material Caused by Electrical Arcing for Application in 240V Arc-Fault Circuit Interrupters  

Microsoft Academic Search

In the development of Arc-Fault Circuit interrupters (AFCIs), one of the most important parameters is the time that an arcing fault could persist before the device will interrupt the current flow and hopefully mitigate fire propagation. In 1996 Underwriters laboratories (UL) published a report on time\\/current ignition characteristics of arcs at 120 V. Despite the very limited number of tests

D. Kolker; S. Campolo; N. DiSalvo

2007-01-01

172

Time-dependent risk of developing distant metastasis in breast cancer patients according to treatment, age and tumour characteristics  

PubMed Central

Background: Metastatic breast cancer is a severe condition without curative treatment. How relative and absolute risk of distant metastasis varies over time since diagnosis, as a function of treatment, age and tumour characteristics, has not been studied in detail. Methods: A total of 9514 women under the age of 75 when diagnosed with breast cancer in Stockholm and Gotland regions during 1990–2006 were followed up for metastasis (mean follow-up=5.7 years). Time-dependent development of distant metastasis was analysed using flexible parametric survival models and presented as hazard ratio (HR) and cumulative risk. Results: A total of 995 (10.4%) patients developed distant metastasis; the most common sites were skeleton (32.5%) and multiple sites (28.3%). Women younger than 50 years at diagnosis, with lymph node-positive, oestrogen receptor (ER)-negative, >20?mm tumours and treated only locally, had the highest risk of distant metastasis (0–5 years' cumulative risk =0.55; 95% confidence interval (CI): 0.47–0.64). Women older than 50 years at diagnosis, with ER-positive, lymph node-negative and ?20-mm tumours, had the same and lowest cumulative risk of developing metastasis 0–5 and 5–10 years (cumulative risk=0.03; 95% CI: 0.02–0.04). In the period of 5–10 years after diagnosis, women with ER-positive, lymph node-positive and >20-mm tumours were at highest risk of distant recurrence. Women with ER-negative tumours showed a decline in risk during this period. Conclusion: Our data show no support for discontinuation at 5 years of clinical follow-up in breast cancer patients and suggest further investigation on differential clinical follow-up for different subgroups of patients. PMID:24434426

Colzani, E; Johansson, A L V; Liljegren, A; Foukakis, T; Clements, M; Adolfsson, J; Hall, P; Czene, K

2014-01-01

173

Changes in microarchitectural characteristics at the tibial epiphysis induced by collagen-induced rheumatoid arthritis over time  

PubMed Central

Background Little is known about the time course of changes in the microarchitecture of the tibial epiphysis with rheumatoid arthritis (RA), although such information would be valuable in predicting risk of fracture. Therefore, we used in vivo microcomputed tomography (?-CT) to assess patterns of microarchitectural alterations in the tibial epiphysis using collagen-induced RA in an animal model. Methods Bovine type II collagen was injected intradermally into the tails of rats for induction of RA. The tibial joints were scanned by in vivo ?-CT at 0, 4, and 8 weeks following injection. Microarchitectural parameters were measured to evaluate alteration patterns of bone microarchitecture at the tibial epiphysis. Results The microarchitectural alterations in an RA group were significantly different from those in a control group from 0 to 4 weeks and from 4 to 8 weeks following injection (P < 0.05). The distribution of trabecular bone thickness and trabecular bone separation from 0 weeks to 8 weeks differed significantly (P < 0.05). Conclusion These results indicate that the patterns of microarchitectural alterations at the tibial epiphysis are strongly affected by collagen-induced progression of RA and entail a severe risk of fracture at the tibial epiphysis. This study represents a valuable first approach to tracking periodic and continuous changes in the microarchitectural characteristics of the tibial epiphysis with collagen-induced RA. PMID:23049249

Lee, Joo Hyung; Chun, Keyoung Jin; Kim, Han Sung; Kim, Sang Ho; Lee, Kwon-Yong; Kim, Dae Jun; Lim, Dohyung

2012-01-01

174

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

175

Noise characteristics in DORIS station positions time series derived from IGN-JPL, INASAN and CNES-CLS analysis centres  

NASA Astrophysics Data System (ADS)

Using wavelet transform and Allan variance, we have analysed the solutions of weekly position residuals of 09 high latitude DORIS stations in STCD (STation Coordinate Difference) format provided from the three Analysis Centres : IGN-JPL (solution ign11wd01), INASAN (solution ina10wd01) and CNES-CLS (solution lca11wd02), in order to compare the spectral characteristics of their residual noise. The temporal correlations between the three solutions, two by two and station by station, for each component (North, East and Vertical) reveal a high correlation in the horizontal components (North and East). For the North component, the correlation average is about 0.88, 0.81 and 0.79 between, respectively, IGN-INA, IGN-LCA and INA-LCA solutions, then for the East component it is about 0.84, 0.82 and 0.76, respectively. However, the correlations for the Vertical component are moderate with an average of 0.64, 0.57 and 0.58 in, respectively, IGN-INA, IGN-LCA and INA-LCA solutions. After removing the trends and seasonal components from the analysed time series, the Allan variance analysis shows that the three solutions are dominated by a white noise in the all three components (North, East and Vertical). The wavelet transform analysis, using the VisuShrink method with soft thresholding, reveals that the noise level in the LCA solution is less important compared to IGN and INA solutions. Indeed, the standard deviation of the noise for the three components is in the range of 5-11, 5-12 and 4-9mm in the IGN, INA, and LCA solutions, respectively.

Khelifa, S.

2014-12-01

176

Capacitance-voltage characteristics and switching time of double barrier resonant tunneling diode fabricated with epi-Si and ?-Al 2O 3  

NASA Astrophysics Data System (ADS)

Capacitance-voltage and conductance-voltage characteristics of resonant tunneling diodes fabricated with epitaxial Si/ ?-Al 2O 3 heterostructure have been studied at room temperature. The capacitance-voltage characteristics of this structure show a large capacitance peak near the resonant tunneling bias. This capacitance peak is considered as quantum capacitance originated from the charge storage in the quantum well of the structure during tunneling process. Capacitance-voltage characteristics also were studied at different frequencies to understand the charge storage mechanism in the resonant tunneling diode structure. Resonant tunneling diodes with different barrier thicknesses were studied and tremendous improvement in the NDR characteristics was observed. A maximum peak-to-valley current ratio of 248 was obtained at room temperature. Using this capacitance value switching time and maximum operational frequency of the RTD structure were determined.

Khatun Mst, Halima; Shahjahan, Mohammad; Sawada, Kazuaki; Ishida, Makoto

2007-01-01

177

Estimating forest structural characteristics with airborne lidar scanning and a near-real time profiling laser systems  

E-print Network

LiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatiallyexplicit mapping of forest characteristics, such as canopy height and Leaf Area Index...

Zhao, Kaiguang

2009-05-15

178

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

PubMed Central

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

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

2014-01-01

179

Far-field spectral intensity characteristics of a time-dependent gaussian pulse from a circular mask with a linear circular apertures array  

Microsoft Academic Search

The spectral characteristics of a time-dependent Gaussian pulse from a circular mask with a circular apertures array in the far field are theoretically investigated and presented with numerical results. A rigorous treatment, with the Fresnel diffraction integral, to the spectral changes of a time-dependent Gaussian-shaped pulse passing through a circular mask with a linear circular apertures array is given and

Pin Han; Hone-Ene Hwang

2004-01-01

180

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  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 treat...

181

Characteristics of the maritime periods during Gosan 2006 and Gosan 2008 The time periods when the HYSPLIT (Draxler et al., 2002) back trajectories for 500, 1000 and 1500  

E-print Network

Characteristics of the maritime periods during Gosan 2006 and Gosan 2008 The time periods when no contact with land surface for five days were classified as maritime. Such periods were found only during Gosan 2006 and Gosan 2008: for Gosan 2006, 15:00, Aug. 21 - 03:00, Aug. 22 (Maritime 1) and 21:00, Aug

Meskhidze, Nicholas

182

Real-time characteristic impedance monitoring for end-point and anomaly detection in the plasma etching process  

NASA Astrophysics Data System (ADS)

We propose a practical and highly sensitive characteristic impedance monitoring (CIM) system for detecting the etching end point and anomalies during the plasma etching process. The CIM system employs a directional coupler and a newly developed vector processing system. The etching end point was successfully detected when a SiO2/Si wafer was etched with CF4 plasma; the system also detected wafer fluttering occurring during SF6-N2 plasma etching. The reactance component of the characteristic impedance primarily changed with the transient response of the electric potential on the inner glass surface during SF6-N2 plasma etching.

Motomura, Taisei; Kasashima, Yuji; Uesugi, Fumihiko; Kurita, Hiroyuki; Kimura, Naoya

2014-01-01

183

CHANGES IN STRUCTURE AND COLOR CHARACTERISTICS OF IRRADIATED CHICKEN BREASTS AS A FUNCTION OF DOSAGE AND STORAGE TIME  

Technology Transfer Automated Retrieval System (TEKTRAN)

Structural change and color characteristics of chicken breasts as a function of irradiation dose and subsequent storage process were investigated by visible spectroscopy and HunterLab measurement. It was found that the ratios of R1 = A485 nm / A560 nm and R2 = A635 nm / A560 nm, which are related...

184

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

185

Effects of injection timing on performance and droplet characteristics of a sixteen-valve four cylinder engine  

Microsoft Academic Search

The performance and droplet characteristics of a sixteen-valve, four cylinder engine operating with combustion in one cylinder\\u000a have been measured with part load, a speed of 1200?rpm and a stoichiometric mixture of gasoline and air. The indicated mean-effective\\u000a cylinder pressure was found to be constant with initiation of injection from 150 to 630 of crank angle after top-dead-centre\\u000a of intake

S. Chappuis; B. Cousyn; M. Posylkin; F. Vannobel; J. H. Whitelaw

1997-01-01

186

Temperature and electric field characteristics of time-dependent dielectric breakdown for silicon dioxide and reoxidized-nitrided oxides  

Microsoft Academic Search

TDDB characteristics of 150 Å reoxidized nitrided oxide (ONO) gate dielectrics were examined at temperatures from 77 K to 400 K. These ONO films were processed with different conditions of rapid thermal nitridation (RTN) and rapid thermal re-oxidation (RTO). Optimized ONO films show better Qbd performance while maintaining a similar temperature and electric field dependence compared to SiO2. The low

Chi-Hung Lin; James Cable; C. S. Woo

1995-01-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

188

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

SciTech Connect

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

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

1982-05-01

189

Waiting to see the specialist: patient and provider characteristics of wait times from primary to specialty care  

PubMed Central

Background Wait times are an important measure of access to various health care sectors and from a patient’s perspective include several stages in their care. While mechanisms to improve wait times from specialty care have been developed across Canada, little is known about wait times from primary to specialty care. Our objectives were to calculate the wait times from when a referral is made by a family physician (FP) to when a patient sees a specialist physician and examine patient and provider factors related to these wait times. Methods Our study used the Electronic Medical Record Administrative data Linked Database (EMRALD) which is a linkage of FP electronic medical record (EMR) data to the Ontario, Canada administrative data. The EMR referral date was linked to the administrative physician claims date to calculate the wait times. Patient age, sex, socioeconomic status, comorbidity and FP continuity of care and physician age, sex, practice location, practice size and participation in a primary care delivery model were examined with respect to wait times. Results The median waits from medical specialists ranged from 39 to 76 days and for surgical specialists from 33 days to 66 days. With a few exceptions, patient factors were not associated with wait times from primary care to specialty care. Similarly physician factors were not consistently associated with wait times, except for FP practice location and size. Conclusions Actual wait times for a referral from a FP to seeing a specialist physician are longer than those reported by physician surveys. Wait times from primary to specialty care need to be included in the calculation of surgical and diagnostic wait time benchmarks in Canada. PMID:24460619

2014-01-01

190

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

191

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

ERIC Educational Resources Information Center

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

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

2014-01-01

192

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...

193

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

194

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

2014-01-01

195

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

196

New space-time perspectives on the propagation characteristics of the Black Death epidemic and its relation to bubonic plague  

Microsoft Academic Search

This work presents, for the first time, a series of detailed space-time maps of Black Death mortality and infected area propagation\\u000a throughout the fourteenth century AD Europe. The maps integrate a variety of interdisciplinary knowledge bases about the devastating\\u000a epidemic and provide researchers and the interested public with an informative description of the Black Death dynamics (temporal\\u000a evolution, local and

George Christakos; Ricardo A. Olea

2005-01-01

197

Numerical and experimental studies of mixing characteristics in a T-junction microchannel using residence-time distribution  

Microsoft Academic Search

The mixing behavior in laminar flow in microchannels is investigated using numerical and experimental approaches. The concept of residence-time distribution (RTD) was applied to indirectly characterize flow and mixing in a T-junction microchannel chosen as a model microchannel mixer\\/reactor. The residence-time distribution used in this study, although a well-known method for characterizing mixing behavior in conventional macro mixers\\/reactors, is still

John T. Adeosun; Adeniyi Lawal

2009-01-01

198

FPGA-based real-time emulation of power electronic systems with detailed representation of device characteristics  

Microsoft Academic Search

This paper presents a Field Programmable Gate Ar- ray (FPGA) based real-time digital simulator for power electronic apparatus based on an realistic device-level behavioral model. A 3-level 12-pulse Voltage Source Converter (VSC) fed induction machine drive is implemented on the FPGA. The VSC model is computed at a fixed time-step of 12.5ns allowing an realistic representation of the IGBT nonlinear

Aung Myaing; Venkata Dinavahi

2011-01-01

199

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

200

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

201

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

202

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

203

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

204

Influence of Extraction Time and Different Sage Varieties on Sensory Characteristics of a Novel Functional Beverage by RSM  

Microsoft Academic Search

An optimized formulation was developed for the preparation of an `ice-sage tea' which might be considered to be a new healthy functional product and designed as an alternative to other cold-served drinks in the market. A central composite design was used for modeling of the experiment with two independent variables (extraction time and blending ratios of two different sage varieties:

B. Özcelik; A. Karadag; T. Cinbas; P. Yolci

2009-01-01

205

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

206

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

ERIC Educational Resources Information Center

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

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

2012-01-01

207

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

208

The effect of manual and mechanical stimulation on oxytocin release and milking characteristics in Holstein cows milked 3 times daily.  

PubMed

Prestimulation administered to a cow before attachment of the milking unit has historically been performed manually. Development of innovative milking technology has allowed manual stimulation to be replaced by mechanical forms of stimulation. Holstein cows (n=30) were enrolled in a crossover design to determine the effect of manual stimulation (forestripping and drying) and high-vibration pulsation on oxytocin profiles, milk yield, milk flow rates, incidence of delayed milk ejection causing bimodal milk flow curves, and residual milk in Holstein cows milked 3 times daily (3×). All cows were subjected to all treatments. Cows received manual (forestripping and drying) or mechanical (high-vibration pulsation) stimulation along with lag times of 0, 30, or 90 s for 21 consecutive milkings. Forestripping involved the manual removal of 2 streams of milk from each teat and drying of the teats. High-vibration pulsation involved increasing the pulsation cycles from 60 to 300 pulses/min and reducing the vacuum in the pulsation chamber to 20 kPa. The 5 treatments were (1) immediate attachment of the milking machine under normal pulsation (T0); (2) dip plus forestrip and drying with 30-s lag time (FD30); (3) dip plus forestrip and drying with 90-s lag time (FD90); (4) high-vibration pulsation for 30 s (HV30); and (5) high-vibration pulsation for 90 s (HV90). Milk yield per milking averaged 14.0kg and was significantly different among treatments; however, the maximum difference detected among treatments was 0.8kg/milking. Milking unit on-time, which represents the time when the milking unit is under normal pulsation and harvesting milk (excluding the high-vibration pulsation time of 30 or 90 s), was shortest (245 s) for cows subjected to 90 s of high-vibration pulsation (HV90) and ranged from 256 to 261 s for all other treatments. Milk harvest may have begun during high-vibration pulsation; however, only 0.13 and 0.32kg of milk was harvested during high-vibration pulsation for HV30 and HV90, respectively. The incidence of bimodal milk curves was lowest for FD90 (7%) and highest for T0 (21%). The somatic cell count was <72×10(3) cells/mL for all treatments. Residual milk obtained by giving 10 IU of oxytocin in the jugular vein followed by 2min of milking unit attachment represented 12 to 14% of the total milk and did not differ among treatments. Endogenous oxytocin profiles peaked between 12.4 and 18.3 pg/mL for all treatments, and the peak occurred sooner in manually stimulated cows; however, we detected no difference in oxytocin concentration beyond 2min after milking unit attachment. High-vibration pulsation elicited a similar oxytocin release when taking the start time of stimulation from manual stimulation or high vibration into consideration. Forestripping for visual observation of milk combined with the use of high-vibration stimulation may reduce variation in the milking routine. A predetermined lag time with minimal variation may be achieved via the time spent in high-vibration stimulation instead of a lag period dictated by milking personnel. PMID:25582591

Watters, Rick D; Bruckmaier, Rupert M; Crawford, Heather M; Schuring, Norm; Schukken, Ynte H; Galton, David M

2015-03-01

209

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

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

210

X-ray observations of characteristic structures and time variations from the solar corona - Preliminary results from Skylab.  

NASA Technical Reports Server (NTRS)

Examples taken from the S-054 X-ray telescope observations made during the first Skylab mission show the hot coronal plasma tracing the configuration of the magnetic fields. The high spectral resolution and sensitivity of the instrument has enabled the following two facts to be more firmly established: (1) that the 'quiet homogeneous corona' is in fact highly structured and that the structures observed appear to be the results of dispersed active region magnetic fields; and (2) that numerous bright points are distributed randomly on the disk. Their presence at high latitudes may play a role in solar cycle models. In addition, the capability of Skylab for studying time evolution has enabled the restructuring of coronal features to be seen at times of high activity, indicating a restructuring of the coronal magnetic fields.

Vaiana, G. S.; Davis, J. M.; Giacconi, R.; Krieger, A. S.; Silk, J. K.; Timothy, A. F.; Zombeck, M.

1973-01-01

211

Characteristics of extenders: Full-time students who take light credit loads and graduate in more than four years  

Microsoft Academic Search

The existing enrollment management and student-institution fit literature generally concentrates on two student populations: persisters and dropouts. This study investigates a third population that we call extenders—those ostensibly full-time students who take longer than normal to complete a bachelor's degree. By analyzing the transcripts and survey responses of undergraduates at a public research university, we identify three groups of extenders:

James Fredericks Volkwein; Wendell G. Lorang

1996-01-01

212

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

213

Enhancement of the characteristics of LCDs by doping nanoparticles: reduction of the operating voltage, viscosity, and response times  

NASA Astrophysics Data System (ADS)

Herein, we report that liquid crystal displays (LCDs) such as TN (twisted nematic)-mode, TB (tunable birefringence)-mode, VAN (vertically aligned nematic)-mode, BN (bent nematic)-mode, and so forth, exhibit the reduction in the operating voltage and response times by doping the nanoparticles of inorganic substances such as MgO. These effects may be attributed to the modification of the physical properties of the liquid crystal host media in these LCD cells.

Sano, Satoru; Miyama, Tomohiro; Takatoh, Kohki; Kobayashi, Shunsuke

2006-02-01

214

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

Microsoft Academic Search

A new optical-fibre radiation dosimeter system, based on radioluminescence and optically stimulated luminescence from carbon-doped aluminium oxide, was developed and tested in clinical photon beams. This prototype offers several features, such as a small detector (1 × 1 × 2 mm3), high sensitivity, real-time read-out and the ability to measure both dose rate and absorbed dose. The measurements describing reproducibility

Marianne C. Aznar; Claus E. Andersen; Lars Bøtter-Jensen; Sven Å. J. Bäck; Sören Mattsson; Flemming Kjær-Kristoffersen; Joakim Medin

2004-01-01

215

Digital remote-action environment for disabled persons: automatic adaptation of the scrolling time to the user's characteristics and intentions  

Microsoft Academic Search

This article deals with a method of automatic adaptation of the scrolling time of the different actions proposed in a man\\/machine interface called “communicator”. The EDITH project (for Digital Remote-action Environment for Disabled persons), elaborated at the University of Metz, was used as a test-bed to define this method. It is only after the clinical evaluation of the EDITH system

Pierre Pino; Eric Brangier; Philippe Arnould

2000-01-01

216

An experimental approach to estimate real-time characteristic of PROFINET IO versus PROFIBUS DP V2  

Microsoft Academic Search

This paper investigates performances of PROFINET IO Class 1, based on Ethernet@100Mbit\\/s, as a replacement of PROFIBUS DP V2, based on RS485 @ 12Mbit\\/s, for the realization of time-critical and isochronous systems. In this work, two test systems have been built. In the first one, the same experimental setup with the same application has been implemented using PROFINET and PROFIBUS

P. Ferrari; A. Flammini; D. Marioli; A. Taroni

2006-01-01

217

Circadian regulation of human sleep and age-related changes in its timing, consolidation and EEG characteristics  

NASA Technical Reports Server (NTRS)

The light-entrainable circadian pacemaker located in the suprachiasmatic nucleus of the hypothalamus regulates the timing and consolidation of sleep by generating a paradoxical rhythm of sleep propensity; the circadian drive for wakefulness peaks at the end of the day spent awake, ie close to the onset of melatonin secretion at 21.00-22.00 h and the circadian drive for sleep crests shortly before habitual waking-up time. With advancing age, ie after early adulthood, sleep consolidation declines, and time of awakening and the rhythms of body temperature, plasma melatonin and cortisol shift to an earlier clock hour. The variability of the phase relationship between the sleep-wake cycle and circadian rhythms increases, and in old age sleep is more susceptible to internal arousing stimuli associated with circadian misalignment. The propensity to awaken from sleep advances relative to the body temperature nadir in older people, a change that is opposite to the phase delay of awakening relative to internal circadian rhythms associated with morningness in young people. Age-related changes do not appear to be associated with a shortening of the circadian period or a reduction of the circadian drive for wake maintenance. These changes may be related to changes in the sleep process itself, such as reductions in slow-wave sleep and sleep spindles as well as a reduced strength of the circadian signal promoting sleep in the early morning hours. Putative mediators and modulators of circadian sleep regulation are discussed.

Dijk, D. J.; Duffy, J. F.

1999-01-01

218

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

219

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

220

[Time lag characteristics of stem sap flow of common tree species during their growth season in Beijing downtown].  

PubMed

From April to September in 2008, the stem sap flow velocity (Js) of several common tree species (Ginkgo biloba, Aesculus chinensis, Magnolia denudata, Robinia pseudoacacia, Pinus tabulaeformis and Cedrus deodara) in Beijing was measured by thermal dissipation method. Crosscorrelation analysis was used to estimate the time lag between the stem sap flow and the driving factors of canopy transpiration among the tree species. The Js of the six tree species was significantly correlated with the total radiation (Rs) and vapor pressure deficit (D), and the Js was lagged behind Rs but ahead of D. The maximum correlation coefficient of Js with Rs (0.74-0.93) was often higher than that of Js with D (0.57-0.79), indicating that the diurnal Js was more dependent on Rs than on D. The sampled tree species except P. tabulaeformis had a shorter time lag of Js with Rs (10-70 min) than with D (47-130 min), and there existed significant differences among R. pseudoacacia, P. tabulaeformis, and C. deodara. The time lag between the Js and the driving factors of canopy transpiration was mainly correlated with the tree features (DBH, tree height, canopy area, and sapwood area) and the nocturnal water recharge, regardless of tree species. PMID:20030130

Wang, Hua; Ouyang, Zhi-yun; Zheng, Hua; Wang, Xiao-ke; Ni, Yong-ming; Ren, Yu-fen

2009-09-01

221

Egg laying characteristics, egg weight, embryo development, hatching weight and post-hatch growth in relation to oviposition time of broiler breeders.  

PubMed

Two experiments were conducted to determine egg laying characteristics and the effects of oviposition time on egg weight, embryo development and post-hatch growth in broiler breeders. In experiment 1, eggs collected for 3 consecutive days on hourly basis between 06:30 and 17:30h were categorized to early, middle and late oviposition times in the clutch. In experiment 2, eggs were incubated to study embryo development, remaining albumen, liver weight, heart weight and the tibia length of embryos at 12, 14, 16 and 18 days of incubation as well as the body weight of hatchlings and chickens at 7, 21 and 42 days of age in relation to oviposition time. About 76% of nest eggs were laid from 06:30 to 11:30h. A similar pattern was observed in floor eggs. Egg weight decreased (P<0.01) with advanced position in the clutch. Generally, oviposition time had no effect on embryo growth parameters. At hatch, body weight of chicks derived from eggs of late oviposition times was less (P<0.01) than that of chicks from eggs produced earlier in the clutch. From 3-week-old onwards, chickens of early oviposition time sustained heavier (P<0.05) weight than chickens of middle oviposition time whereas chickens of late oviposition time obtained a middle weight. Differences in egg weights, body weight at hatch and post-hatch growth due to time of oviposition suggest that oviposition time together with incubation conditions should be considered for obtaining greater uniformity and growth of chickens. PMID:25818523

Akil, R; Zakaria, A H

2015-05-01

222

Performance study of cementitious systems containing zeolite and silica fume: effects of four metal nitrates on the setting time, strength and leaching characteristics.  

PubMed

The aim of this study is to investigate the effect of four metal nitrate contaminants, namely chromium, manganese, lead and zinc on the mechanical and leaching characteristics of cement-based materials. For this purpose, three different matrices made of: (i) Portland cement, (ii) Portland cement and silica fume, and (iii) Portland cement and natural zeolite were studied. The effects of metals on the stabilised/solidified (S/S) product characteristics were monitored by measuring: (i) setting time, (ii) compressive strength, (iii) acid neutralisation capacity (ANC), and (iv) solubility of the metal contaminants as a function of pH. The results of both mechanical and leaching tests showed the importance of the contaminant/matrix couple considered. Setting time was accelerated in presence of chromium, while in presence of manganese, lead and zinc it was delayed. However, for the last two contaminants, a 10% replacement of cement by silica fume and zeolite, markedly accelerated the setting time compared to the cement-only matrix. Although the early strength development was adversely affected in presence of all four contaminants, the long-term strength was less affected compared to the control materials. Although the ANC of the materials was not markedly affected by the presence of contaminants, the nature of the matrix did modify the ANC behaviour of the solidified materials. The increased strength and reduced ANC observed in the presence of silica fume are both due to pozzolanic reaction. The type of matrix used for solidification did not affect the solubility of the four metal contaminants. Overall, the results showed that the use of blended cements must be carried out with care and the performance assessment of waste-containing cement-based materials must take into consideration both the mechanical and leaching characteristics of the systems. PMID:12117465

Gervais, C; Ouki, S K

2002-07-22

223

Write-once-read-many-times characteristics of Pt/Al2O3/ITO memory devices  

NASA Astrophysics Data System (ADS)

Nonvolatile write-once-read-many-times (WORM) Pt/Al2O3/ITO memory devices prepared at room temperature were demonstrated. The WORM memory devices show irreversible transition from the initial low resistance (ON) state to the high resistance (OFF) state, high ON/OFF ratio, long data retention, and good reading endurance in air at room temperature. The high performances are promising for employing the Pt/Al2O3/ITO WORM memory devices in permanent storage of information. The nonvolatile memory behaviors could be attributed to the formation and permanent rupture of conductive filament consisting of positively charged oxygen vacancies.

Wu, Shuxiang; Chen, Xinman; Ren, Lizhu; Hu, Wei; Yu, Fengmei; Yang, Kungan; Yang, Mei; Wang, Yunjia; Meng, Meng; Zhou, Wenqi; Bao, Dinghua; Li, Shuwei

2014-08-01

224

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

225

Improvements of Real Time First Motion Focal Mechanism and Noise Characteristics of New Sites at the Puerto Rico Seismic Network  

NASA Astrophysics Data System (ADS)

Seismic networks need quick and efficient ways to obtain information related to seismic events for the purposes of seismic activity monitoring, risk assessment, and scientific knowledge among others. As part of an IRIS summer internship program, two projects were performed to provide a tool for quick faulting mechanism and improve seismic data at the Puerto Rico Seismic Network (PRSN). First, a simple routine to obtain a focal mechanisms, the geometry of the fault, based on first motions was developed and implemented for data analysts routine operations at PRSN. The new tool provides the analyst a quick way to assess the probable faulting mechanism that occurred while performing the interactive earthquake location procedure. The focal mechanism is generated on-the-fly when data analysts pick P wave arrivals onsets and motions. Once first motions have been identified, an in-house PRSN utility is employed to obtain the double couple representation and later plotted using GMT's psmeca utility. Second, we addressed the issue of seismic noise related to thermal fluctuations inside seismic vaults. Seismic sites can be extremely noisy due to proximity to cultural activities and unattended thermal fluctuations inside sensor housings, thus resulting in skewed readings. In the past, seismologists have used different insulation techniques to reduce the amount of unwanted noise that a seismometers experience due to these thermal changes with items such as Styrofoam, and fiber glass among others. PRSN traditionally uses Styrofoam boxes to cover their seismic sensors, however, a proper procedure to test how these method compare to other new techniques has never been approached. The deficiency of properly testing these techniques in the Caribbean and especially Puerto Rico is that these thermal fluctuations still happen because of the intense sun and humidity. We conducted a test based on the methods employed by the IRIS Transportable Array, based on insulation by sand burial of the sensor. Two Guralps CMG-3T's connected to RefTek's 150 digitizers were used at PRSN's MPR site seismic vault to compare the two types of insulation. Two temperature loggers were placed along each seismic sensor for a period of one week to observe how much thermal fluctuations occur in each insulation method and then compared its capability for noise reduction due to thermal fluctuations. With only a single degree Celsius fluctuation inside the sand (compared to almost twice that value for the foam) the sensor buried in sand provided the best insulation for the seismic vault. In addition, the quality of the data was analyzed by comparing both sensors using PQLX. We show results of this analysis and also provide a site characteristic of new stations to be included in the daily earthquake location operations at the PRSN.

Williams, D. M.; Lopez, A. M.; Huerfano, V.; Lugo, J.; Cancel, J.

2011-12-01

226

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.

1996-01-01

227

A Time-Series Model of Phase Amplitude Cross Frequency Coupling and Comparison of Spectral Characteristics with Neural Data  

PubMed Central

Stochastic processes that exhibit cross-frequency coupling (CFC) are introduced. The ability of these processes to model observed CFC in neural recordings is investigated by comparison with published spectra. One of the proposed models, based on multiplying a pulsatile function of a low-frequency oscillation (?) with an unobserved and high-frequency component, yields a process with a spectrum that is consistent with observation. Other models, such as those employing a biphasic pulsatile function of a low-frequency oscillation, are demonstrated to be less suitable. We introduce the full stochastic process time series model as a summation of three component weak-sense stationary (WSS) processes, namely, ?, ?, and ?, with ? a 1/f? noise process. The ? process is constructed as a product of a latent and unobserved high-frequency process x with a function of the lagged, low-frequency oscillatory component (?). After demonstrating that the model process is WSS, an appropriate method of simulation is introduced based upon the WSS property. This work may be of interest to researchers seeking to connect inhibitory and excitatory dynamics directly to observation in a model that accounts for known temporal dependence or to researchers seeking to examine what can occur in a multiplicative time-domain CFC mechanism.

Lepage, Kyle Q.; Vijayan, Sujith

2015-01-01

228

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

229

Reproductive characteristics in female Swedish moose (Alces alces), with emphasis on puberty, timing of oestrus, and mating  

PubMed Central

Background The moose (Alces alces) is an intensively managed keystone species in Fennoscandia. Several aspects of reproduction in moose have not been fully elucidated, including puberty, timing of mating and oestrus, and the length of the oestrus period. These aspects are relevant for an adaptive management of moose with respect to harvest, population size, demography and environmental conditions. Therefore, an investigation of female moose reproduction was conducted during the moose-hunting period in southern Sweden from 2008 to 2011. Results A total of 250 reproductive organs and information on carcass weight and age was collected from four different hunting areas (provinces of Öland, Småland, Södermanland, and Västergötland) in southern Sweden. The results showed that puberty in female moose varied with carcass weight, age, and time of season. The period for oestrous/mating lasted from about mid September to the beginning of November. Conclusions The oestrus period (predominantly for heifers) is longer than previously reported and was not finished when the hunting period started. Sampling the uterine cervix to detect spermatozoa was a useful method to determine if mating had occurred. To avoid hunting of moose during oestrus, we suggest that the hunting period should be postponed by at least 14 days in southern Sweden. PMID:24735953

2014-01-01

230

Characteristics of microbial communities in steppe paleosols buried under kurgans of the Sarmatian time (I-IV centuries AD)  

NASA Astrophysics Data System (ADS)

Microbiological studies of paleosols buried under steppe kurgans of different ages of the Middle (I-II centuries AD) and Late Sarmatian (II-IV centuries AD) time in different regions of the Lower Volga steppes were carried out. The regularities of the soil microbial communities’ development were determined in the I-IV centuries AD by the climate dynamics and the replacement of the relatively humid conditions (the I century to the first half of the II century) by dry (the second half of the II century to the first half of the III century) and then again by humid (the end of the III century to the IV century) conditions. In the humid climatic periods, the active biomass of the microorganisms and its portion in the total microbial biomass and the Corg of the soil increased, the portion of microorganisms consuming plant residues increased in the ecological-trophic structure of the microbial community, and the index of oligotrophy decreased. These changes had an opposite direction in the arid climatic periods. The variations of the microbiological parameters relative to the century-long dynamics of the climate over the historical time were synchronous and unidirectional, though the studied soils were found in different soil-geographical zones (dry and desert steppe), natural regions (the Privolzhskaya and Ergeni uplands and the Caspian Lowland), and landforms (watersheds, river terraces, marine plains).

Demkina, T. S.; Khomutova, T. E.; Kashirskaya, N. N.; Stretovich, I. V.; Demkin, V. A.

2009-07-01

231

Effect of Annealing Time on Microstructural Evolution and Deformation Characteristics in 10Mn1.5Al TRIP Steel  

NASA Astrophysics Data System (ADS)

To investigate microstructural evolution and its effects on the deformation behaviors of cold-rolled 10Mn1.5Al TRIP steel, a series of intercritical annealing treatments with various holding times from 3 minutes to 48 hours were conducted. With the increase of the holding time from 3 minutes to 12 hours, the elongation was improved from 15 to 42 pct, while the tensile strength was only reduced from 1210 to 1095 MPa; the strength-ductility combination thus exceeded 45 GPa pct. Austenite was found to coexist with martensite within deformed grains, which reduced the strain concentration at the interface. The austenite transformation fraction, as measured from the {220} peaks, after 3 minutes annealing was half that after 12 hours annealing. This is an indication that the slip systems were more easily activated in the micro-scaled grains compared with nano-scaled grains. Therefore, although the stability of austenite would have increased during annealing, size-induced slip suppression was reduced. Thus, more strain was accommodated in the austenite, facilitating a greater strain-induced transformation and better ductility.

Han, Qihang; Zhang, Yulong; Wang, Li

2015-03-01

232

Effect of cationic surfactants on characteristics and colorimetric behavior of polydiacetylene/silica nanocomposite as time-temperature indicator  

NASA Astrophysics Data System (ADS)

Polydiacetylene (PDA)/silica nanocomposites were synthesized by self-assembly method using polymerizable amphiphilic diacetylene monomers, 10,12-pentacosadiynoic acid (PCDA). Addition of cationic surfactants (PDADMAC and CTAB) to PDA/SiO2 nanocomposites induced higher intermolecular force which affected their size, shape and color transition. Pure PDA, PDA/SiO2, PDA/SiO2/PDADMAC and PDA/SiO2/CTAB were investigated by particle size analysis, TEM, SEM, UV-vis spectroscopy and FT-IR. It was found that the PDA/SiO2 nanocomposites exhibited slightly larger particle sizes than those of other samples. The PDA/SiO2 nanocomposites with a core-shell structure were almost regarded as spherical-shaped particles. Cationic surfactants, especially CTAB, presumably affected the particle size and shape of PDA/SiO2 nanocomposites due to the disruption of hydrogen bonding between PDA head group and ammonium group. The colorimetric response of both PDA/SiO2/surfactant and surfactant-free PDA/SiO2 aqueous solutions directly changed in relation to time and temperature; thus they were expected to be applied as a new polymer-based time-temperature indicator (TTI).

Nopwinyuwong, Atchareeya; Kitaoka, Takuya; Boonsupthip, Waraporn; Pechyen, Chiravoot; Suppakul, Panuwat

2014-09-01

233

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

234

Time-dependent effects of isoflurane and dexmedetomidine on functional connectivity, spectral characteristics, and spatial distribution of spontaneous BOLD fluctuations.  

PubMed

Anesthesia is often necessary to perform fMRI experiments in the rodent model; however, commonly used anesthetic protocols may manifest changing brain conditions over the duration of the study. This possibility was explored in the current work. Eleven rats were anesthetized with 2% isoflurane anesthesia; four rats were anesthetized for a short period (30?min, simulating induction and fMRI setup) and seven rats were anesthetized for a long period (3?h, simulating surgical preparation). Following the initial anesthetic period, isoflurane was discontinued, and a dexmedetomidine bolus (0.025?mg/kg) and continuous subcutaneous infusion (0.05?mg/kg/h) were administered. Blood-oxygen-level dependent resting state imaging was performed every 30?min from 0.75?h post dexmedetomidine bolus until 5.75?h post-bolus. Evaluation of power spectra obtained from time courses in the primary somatosensory cortex revealed, in general, a monotonic increase in low-frequency power (0.05-0.3?Hz) in both groups over the duration of resting state imaging. Greater low-band spectral power (0.05-0.15?Hz) is present in the short isoflurane group for the first 2.75?h, but the spectra become highly uniform at 3.25?h. The emergence of a ~0.18?Hz peak, beginning at the 3.75?h time point, exists in both groups and evolves similarly, increasing in strength as the duration of dexmedetomidine sedation (and time since isoflurane cessation) extends. In the long isoflurane group only, bilateral functional connectivity strengthens with anesthetic duration, and correlation is linearly linked to low-band spectral power. Convergence of connectivity and spectral metrics between the short and long isoflurane groups occurs at ~3.25?h, suggesting the effects of isoflurane have subsided. Researchers using dexmedetomidine following isoflurane for functional studies should be aware of the duration specific effects of the pre-scan isoflurane durations as well as the continuing influences of long-term imaging under dexmedetomidine. PMID:24449532

Magnuson, Matthew Evan; Thompson, Garth John; Pan, Wen-Ju; Keilholz, Shella Dawn

2014-03-01

235

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

236

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

237

Effects of pressure and deposition time on the characteristics of In2Se3 films grown by magnetron sputtering  

NASA Astrophysics Data System (ADS)

Crystalline In2Se3 films were fabricated by magnetron sputtering from a sintered In2Se3-compound target and the effects of the deposition parameters, including the working pressure and deposition time, on the phase composition, structure, morphology, and optical properties were clarified. Single-phase ?-In2Se3 was prepared at 4.0 Pa, but ?-In2Se3 was recognized when the working pressure was lower than 4.0 Pa. The optical transmittance of the films decreased to 45% and the optical band gap varied from 2.9 to 2.0 eV with increasing film thickness from 80 to 967 nm. Metal-semiconductor-metal (MSM) photodetectors based on ?-In2Se3 thin films with various thicknesses were also fabricated. The result of photosensitivity research on such MSM photodetectors suggests that it may be impossible to fabricate wide-absorption-range MSM devices by just using a single material ( ?-In2Se3) because of spatial potential fluctuations in the layers. [Figure not available: see fulltext.

Yan, Yong; Li, Shasha; Ou, Yufeng; Ji, Yaxin; Yu, Zhou; Liu, Lian; Yan, Chuanpeng; Zhang, Yong; Zhao, Yong

2014-11-01

238

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. The data of the ISPSDs show that the inorganic and organic Suspended Particulate Matter (SPM), as found in the Elbe and Weser estuaries, mostly appears in a flocculated state. The substrate for organic matter is mainly imported from the seaside and transported into the estuaries as indicated by an upstream decrease of the amount of fine particles. In winter, when the freshwater discharge is high, different PPSDs are found in the case of the Elbe estuary in the Turbidity Maximum Zone (TMZ) as well as in the landward and in the seaward sections close to the TMZ. In summer, the distance between the seaward and the landward section is too low to obtain an individual PPSD within the Elbe TMZ. A missing correlation between the PPSD and ISPSD shows that the inorganic constituents do not have an influence on the in-situ floc size. Although flocs aggregate and disaggregate over a tidal cycle and with changing SSC, they do not change their PPSD. The microflocs are therefore strong enough to withstand further breakage into their inorganic constituents.

Papenmeier, Svenja; Schrottke, Kerstin; Bartholomä, Alexander

2014-01-01

239

The impact of dietary fat withdrawal on carcass iodine value, belly characteristics, and changes in body fat over time.  

PubMed

The inclusion of unsaturated fats in pig diets has raised issues related to pork carcass fat quality. The objective of this experiment was to understand how withdrawal from the diet of unsaturated dietary fat before slaughter impacts the composition of jowl fat during the growth cycle and at market. Fifty individually housed pigs (PIC 337 × C22/29; initial BW = 59.3 ± 0.55 kg) were allotted based on sex and initial BW to 10 treatments for an 82-d experiment as follows: 3 dietary fat withdrawal times before slaughter (21, 42, or 63 d) by 3 dietary fat unsaturation loads (DFUL), which includea high intake of unsaturated fatty acids supplied through an inclusion of 5% corn oil (HIGH), a high intake of a mixture of saturated and unsaturated fatty acids supplied through an inclusion of 5% animal-vegetable blend (MED), and a moderate intake of unsaturated fatty acids supplied through an inclusion of 2.5% corn oil (LOW). Pigs were weighed and jowl adipose samples were collected on d 0, 21, 42, and 63 and at harvest on d 82. Data were analyzed using PROC MIXED with treatment and sex as fixed effects. At market (d 82), increasing the withdrawal of dietary fat further away from market increased 18:1 (P = 0.045) and tended to increase 14:0 concentrations (P = 0.054). It also significantly decreased 18:2 (P < 0.001) and tended to decrease 18:3 concentrations (P = 0.081). A HIGH DFUL resulted in the greatest 18:2 concentrations in jowl fat followed by LOW; MED resulted in the lowest 18:2 levels (P < 0.001). Dietary fat withdrawal before market significantly reduced carcass iodine value (IV) measured at d 82 (P = 0.006). In conclusion, elevated 18:2 intake makes lowering carcass IV in the depot fat very difficult and may take as long as 61 d. The withdrawal of unsaturated dietary fat apparently altered the fat depot to be more reflective of fat synthesized de novo, resulting in a more saturated depot fat. Importantly, this alteration of deposited fat composition did not translate into improved belly firmness, depth, weight, or fat color. PMID:25568373

Kellner, T A; Prusa, K J; Patience, J F

2015-01-01

240

[Leisure-time physical activities among adults in Florianopolis, state of Santa Catarina, Brazil: a population-based study on the characteristics of the practices and the practitioners].  

PubMed

The study established characteristics of practices and practitioners of leisure-time physical activities among adults in Florianopolis, Brazil. It was a population-based, cross-sectional survey conducted between September 2009 and January 2010. Leisure-time physical activity was assessed using a validated questionnaire. Walking and weight lifting were the most frequently reported activities. Vigorous physical activities were more frequent among men and young adults. There were no gender or age differences in relation to the frequency and duration of physical activities. Walking and gymnastics were more frequently practiced by women, and jogging and soccer by men. Age was positively associated with walking, and negatively with soccer and weight lifting. Caucasian and black males practiced gymnastics and soccer more frequently. Adults living with a partner practiced more walking and soccer, and less weight lifting. Educational level was directly associated with jogging and gymnastics, but inversely with soccer. Income was inversely associated with soccer and directly associated with weight lifting. Policies to promote physical activity should consider the different interests of the population to stimulate the scope of their practice in leisure-time. PMID:25351325

Del Duca, Giovâni Firpo; Nahas, Markus Vinicius; Hallal, Pedro Curi; Peres, Karen Glazer

2014-11-01

241

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. PMID:24312773

Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

2012-01-01

242

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

243

Time-dependent characteristic of negative feedback optical amplifier at bit rates 10-Gbit/s based on an optical triode  

NASA Astrophysics Data System (ADS)

We proposed and demonstrated an all-optical triode based on a tandem wavelength converter using cross-gain modulation (XGM) in semiconductor optical amplifiers (SOAs). Negative feedback optical amplification scheme, which has the key advantages of reducing bit error rate and waveform reshaping at the output, was employed in this optical triode. This scheme utilizes an input signal and a negative feedback signal (a signal with reverse intensity to the input) and they were fed together into the optical amplifier. Manipulating the intensity of negative feedback signal enabled the noise suppression effect to be optimized and the outputs recorded improvements in bit error rate (BER) and also undergone waveform reshaping shown by the eye-pattern. In negative feedback optical amplifier, the negative feedback signal and input signal were fed into the SOA. However, due to XGM mechanism, there is a setback in which both signals could not be simultaneously fed. Therefore, by using an optical delay, negative feedback timing was manipulated and we investigate timing characteristics of negative feedback optical amplifier with BER and eye-pattern waveforms at 10 Gb/s.

Harada, Yuki; Azmi, Mohamad Syafiq; Azizan, Siti Aisyah; Matsutani, Takaomi; Maeda, Yoshinobu

2015-01-01

244

Characteristics of individual rain events and its dependency on the minimum inter-event time in a dry desert area in north China  

NASA Astrophysics Data System (ADS)

The rain event characteristics was analysed using a pluviograph record of 2008 from an arid desert area of Shapotou in the Tengger Desert, China. Changing the minimum inter-event time (MIT) from 30 min to 24 h alters the number of rain events from 72 to 21. The mean rain rate declines from 0.85 mm h-1 to 0.4 mm h-1, and the geometric mean event duration rises from 0.64 h to 5.04 h. The number of rain events, the mean rain rate, and the geometric mean event duration differed under different criteria of individual rain depth (e.g., 0.1, 0.5, 1.0, 5.0 mm), except that for an individual rain depth of 0.5, 1.0, and 5.0 mm, the features (the number of rain events, the mean rain rate, and the geometric mean event duration) mentioned above are identical for MIT=2 and 3 h. Therefore, there is no need for further identification to set MIT at two or three hours in this specific arid desert area. This wide variation in the properties of rain events indicates that more attention needs to be paid to the selection and reporting of event criteria in studies that adopt event-based data analysis. The selection of a MIT criterion is shown to involve a compromise between the independence of widely-spaced events and their increasingly variable intra-event characteristics (Dunkerley, Hydrological Processes, 2008, 22(26): 5024-5036).

Wang, X.

2009-04-01

245

Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ˜120-145 K above the measured glass transition temperatures (˜207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (˜70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (?2) and new non-Gaussian (?) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.

Das, Anuradha; Das, Suman; Biswas, Ranjit

2015-01-01

246

Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): time-resolved fluorescence measurements and all-atom molecular dynamics simulations.  

PubMed

Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ?120-145 K above the measured glass transition temperatures (?207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (?70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (?2) and new non-Gaussian (?) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems. PMID:25612718

Das, Anuradha; Das, Suman; Biswas, Ranjit

2015-01-21

247

Comparison of the physiological responses and time-motion characteristics of young soccer players in small-sided games: the effect of goalkeeper.  

PubMed

Köklü, Y, Sert, Ö, Alemdaro?lu, U, and Arslan, Y. Comparison of the physiological responses and time-motion characteristics of young soccer players in small-sided games: The effect of goalkeeper. J Strength Cond Res 29(4): 964-971, 2015-The purpose of this study was to investigate the effect of "with goalkeeper" (SSGwith) and "without goalkeeper" (SSGwithout) conditions on players' physiological responses and time-motion characteristics in small-sided games. Sixteen young soccer players (age: 16.5 ± 1.5 years; height: 175.5 ± 5.2 cm; body mass: 63.0 ± 6.9 kg; training experience: 6.3 ± 1.3 years) participated in 2 different 2-a-side, 3-a-side, and 4-a-side games: SSGwith and SSGwithout. The players underwent anthropometric measurements (height and body mass) followed by the Yo-Yo intermittent recovery test (level 1). Then they played 2-a-side, 3-a-side, and 4-a-side SSGwith and SSGwithout soccer-specific SSGs in random order at 2-day intervals. Heart rate (HR) responses and distance covered in different speed zones (walking [WLK, 0-6.9 km·h], low-intensity running [LIR, 7.0-12.9 km·h], moderate-intensity running [MIR, 13.0-17.9 km·h], and high-intensity running [HIR, >18 km·h]) were measured during the SSGs, whereas the rating of perceived exertion (RPE) and blood lactate (La) were determined at the end of the last bout of each SSG. During the SSGwithout players showed higher %HR, La, and RPE (p ? 0.05), greater distance covered in LIR, MIR, HIR, and total distance (p ? 0.05) compared with the SSGwith during the 2-a-side, 3-a-side, and 4-a-side games. The results of this study suggest that both SSGwith and SSGwithout could be used for the physiological adaptations required for soccer-specific aerobic endurance. However, if coaches want both higher physiological responses and greater distance covered in the intensity running zone from their teams, SSGwithout should be organized. In addition, this study also suggests that smaller format games (i.e., 2-a-side) may promote some anaerobic adaptations for youth soccer players. PMID:23942169

Köklü, Yusuf; Sert, Özcan; Alemdaro?lu, Utku; Arslan, Yunus

2015-04-01

248

When holding your horses meets the deer in the headlights: time-frequency characteristics of global and selective stopping under conditions of proactive and reactive control  

PubMed Central

The ability to inhibit unwanted thoughts or actions is crucial for successful functioning in daily life; however, this ability is often impaired in a number of psychiatric disorders. Despite the relevance of inhibition in everyday situations, current models of inhibition are rather simplistic and provide little generalizability especially in the face of clinical disorders. Thus, given the importance of inhibition for proper cognitive functioning, the need for a paradigm, which incorporates factors that will subsequently improve the current model for understanding inhibition, is of high demand. A popular paradigm used to assess motor inhibition, the stop-signal paradigm, can be modified to further advance the current conceptual model of inhibitory control and thus provide a basis for better understanding different facets of inhibition. Namely, in this study, we have developed a novel version of the stop-signal task to assess how preparation (that is, whether reactive or proactive) and selectivity of the stopping behavior effect well-known time-frequency characteristics associated with successful inhibition and concomitant behavioral measures. With this innovative paradigm, we demonstrate that the selective nature of the stopping task modulates theta and motoric beta activity and we further provide the first account of delta activity as an electrophysiological feature sensitive to both manipulations of selectivity and preparatory control. PMID:25540615

Lavallee, Christina F.; Meemken, Marie T.; Herrmann, Christoph S.; Huster, Rene J.

2014-01-01

249

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. PMID:24251279

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

2013-01-01

250

Real-time electrocardiogram P-QRS-T detection-delineation algorithm based on quality-supported analysis of characteristic templates.  

PubMed

The main objective of this study is to introduce a simple, low-latency, and accurate algorithm for real-time detection of P-QRS-T waves in the electrocardiogram (ECG) signal. In the proposed method, real-time signal preprocessing, which includes high frequency noise filtering and baseline wander reduction, is performed by applying discrete wavelet transform (DWT). A method based on signal first-order derivative and adaptive threshold adjustment is employed for real-time detection of the QRS complex. Moreover, detection and delineation of P- and T-waves are achieved by correlation analysis conducted between signal and their templates. Besides, signal quality is investigated online, and if the quality of the analysis window is unacceptable, then the algorithm will guess (estimate) the locations of P- and T-waves. The operating characteristics of the proposed algorithm are evaluated by its implementation to an artificially generated ECG signal whose quality is adjustable from the best (Quality, 100%) to the worst (Quality, ?40%) cases based on the random-walk noise theory. The algorithm was applied to the MIT-BIH arrhythmia database, QT database, and Physionet/CinC challenge 2011competition database. The obtained results, which were based on the QT database, showed sensitivity and positive predictivity of Se=99.63% and P+=99.83%, Se=99.83% and P+=99.98%, and Se=99.74% and P+=99.89% for the detection of P-, QRS-, and T-waves, respectively, and the obtained results, which were based on the MIT-BIH arrhythmia database, showed Se=99.81% and P+=99.70% for the detection of the QRS complex. Moreover, it will be shown that the results of the proposed method are reliable for a minimum signal quality value of 70%. According to numerical assessments, 8-ms after the occurrence of R-wave, its location will be identified by the computer code of the proposed algorithm. This parameter is 198-ms and 177-ms for P- and T-waves, respectively. PMID:25063881

Karimipour, Atiyeh; Homaeinezhad, Mohammad Reza

2014-09-01

251

Determination of time-of-travel, dispersion characteristics, and oxygen reaeration coefficients during low streamflows--Lower Tacony/Frankford Creek, Philadelphia, Pennsylvania  

USGS Publications Warehouse

Time-of-travel, dispersion characteristics, and oxygen reaeration coefficients were determined by use of dye and gas tracing for a 2-mile reach of Tacony/Frankford Creek in Philadelphia, southeastern Pennsylvania. The reach frequently has concentrations of dissolved oxygen (DO) below the water-quality standard of 4 milligrams per liter during warm months. Several large combined sewer overflows (CSOs), including one of the largest in Philadelphia (former Wingohocking Creek), discharge to the study reach in this urbanized watershed, affecting water quality and the timing and magnitude of storm peaks. In addition, a dam that commonly results in backwater conditions and reduced natural reaeration is present a few hundred feet from the end of the study reach. Time-of-travel and reaeration data were collected under base-flow conditions in August and September 2009 for three sub-reaches from Roosevelt Boulevard (U.S. Route 1) to Castor Avenue. Determination of traveltimes to the centroid of the dye cloud were needed for calculation of the reaeration coefficients. Results of the dye study in Tacony/Frankford Creek indicate that traveltimes were affected by the presence of man-made structures, such as the large scour hole and pool developed at the outfall of the T14 CSO and the dam, both of which reduce stream velocities. Mean stream velocities during the dye-tracer tests ranged from a maximum of 0.44 to 0.04 foot per second through a large pool. The dispersion efficiency of the stream was determined from relations between normalized unit concentrations to time to peak for use in water-quality modeling. Oxygen reaeration coefficients determined by a constant rate-injection method using propane as the tracer gas were as low as 0.04 unit per hour in a long pool affected by backwater conditions behind a dam. The highest reaeration coefficient was 2.29 units per hour for a steep-gradient reach with multiple winding channels through gravel deposits, just downstream of a large scour pool developed at the outlet of the T14 CSO. Reaeration coefficients determined from the field tracer-gas method were compared to values calculated by two other methods, one that is based on theoretical equations using physical properties of the stream as variables and the other that is based on equations using the timing of measured daily maximum DO concentrations in the stream. Reaeration coefficients from the two alternate methods were most similar to values determined from the field tracer-gas method for the upstream portion of the study reach, characterized by free-flowing riffle and pools. Values of reaeration coefficients determined by the tracer-gas method were 2 to 10 times higher than values determined by 2 alternate methods for most subreaches hydraulically affected by man-made structures. In addition to the tracer gas, propane, the gas analysis also included methane, ethane, and ethene, of which only methane was measured in concentrations above a few micrograms per liter. Methane, thought to occur naturally or because of ongoing processes in the stream, was measured in concentrations ranging from 6.6 to 78 micrograms per liter; the concentrations were greatest in sub-reaches dominated by pools.

Senior, Lisa A.; Gyves, Matthew C.

2010-01-01

252

Experiments on hypersonic boundary layer transition on blunt cones with acoustic-absorption coating  

NASA Astrophysics Data System (ADS)

The laminar-turbulent transition is studied experimentally on a cone with an acoustic-absorption coating and with different nose bluntness in a high-speed flow. The acoustic-absorption coating is a felt metal sheet with a random microstructure. Experiments were carried out on a 1-meter length 7 degree cone at free-stream Mach number M = 8 and zero angle of attack. Locations of the laminar-turbulent transition are detected using heat flux distributions registered by calorimeter sensors. In addition, boundary layer pulsations are measured by means of ultrafast heat flux sensors. It is shown that the laminar-turbulent transition is caused by the second-mode instability, and the laminar run extends as the bluntness is increased. The porous coating effectively suppresses this instability for all tested bluntness values and 1.3-1.85 times extends the laminar run.

Shiplyuk, A.; Lukashevich, S.; Bountin, D.; Maslov, A.; Knaus, H.

2012-01-01

253

Comparison of sludge characteristics and performance of a submerged membrane bioreactor and an activated sludge process at high solids retention time.  

PubMed

This work aims to compare biomass structure and performance of a submerged membrane bioreactor (SMBR) and an activated sludge process (ASP) treating the same domestic wastewater. The influence of the separation technique (membrane filtration or settling) and operation at high sludge-retention time (SRT) were investigated. Over the entire range of SRT (10-110 days), the SMBR achieved very good organic removal efficiencies, ranging from 90.8+/-0.2% to 94.2+/-1.6% based on total COD (TCOD), whereas those of ASP were between 87.4+/-1.8% and 90.3+/-0.8%. The contribution of the membrane in the increase in performance was due to total suspended solid retention and also partly due to retention of proteins and polysaccharides of the sludge supernatant. No significant difference in excess sludge production was observed between the two processes operated at the same SRT, but sludge production in SMBR decreased from 0.31 to 0.13 g(VSS)g(COD)(-1) as SRT increased from 9 to 110 days. The difference in sludge characteristics and performance was especially pronounced as SRT increased, resulting in deterioration of sludge settleability and effluent quality of the ASP (filamentous bacteria, increase of protein and polysaccharide release). Membrane filtration induced accumulation of soluble and colloidal proteins and polysaccharides which were progressively degraded in the supernatant as the SRT increased. At similar SRT, no significant difference was observed in the amount of extractable exocellular polymeric substances (bound EPS) from ASP and SMBR sludge. However as the SRT increased, the total specific amount of bound EPS in flocs decreased and the ratio proteins/polysaccharides also decreased. Concomitantly, laser diffraction analysis, microscopic observations, turbidity and DSVI measurement showed that the SRT increase induced significant modifications in sludge morphology in SMBR: decrease in floc size, densification of aggregates, and development of non-flocculating organisms. PMID:16759682

Massé, Anthony; Spérandio, Mathieu; Cabassud, Corinne

2006-07-01

254

Step-changes in the physical, chemical and biological characteristics of the Gulf of Maine, as documented by the GNATS time series  

USGS Publications Warehouse

We identify step-changes in the physical, chemical and biological characteristics of the Gulf of Maine (GoM) using the Gulf of Maine North Atlantic Time Series (GNATS), a series of oceanographic measurements obtained between September 1998 and December 2010 along a transect in the GoM running from Portland, ME, to Yarmouth, NS. GNATS sampled a period of extremes in precipitation and river discharge (4 of the 8 wettest years of the last century occurred between 2005 and 2010). Coincident with increased precipitation, we observed the following shifts: (1) decreased salinity and density within the surface waters of the western GoM; (2) both reduced temperature and vertical temperature gradients in the upper 50 m; (3) increased colored dissolved organic matter (CDOM) concentrations and particle scattering in the western GoM; (4) increased concentrations of nitrate and phosphate across all but the eastern GoM; (5) increased silicate, particularly in the western GoM, with a sharp increase in the ratio of silicate to dissolved inorganic nitrogen; (6) sharply decreased carbon fixation by phytoplankton; (7) moderately decreased chlorophyll, particulate organic carbon (POC) and particulate inorganic carbon (PIC) in the central GoM and (8) decreased POC- and PIC-specific growth rates. Gulf-wide anomaly analyses suggest that (1) the surface density changes were predominantly driven by temperature, (2) dissolved nutrients, as well as POC/PON, varied in Redfield ratios and (3) anomalies for salinity, density, CDOM, particle backscattering and silicate were significantly correlated with river discharge. Precipitation and river discharge appear to be playing a critical role in controlling the long-term productivity of the Gulf of Maine by supplying CDOM and detrital material, which ultimately competes with phytoplankton for light absorption.

Balch, William M.; Drapeau, D.T.; Bowler, B.C.; Huntington, Thomas G.

2012-01-01

255

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.

256

Recovery of topsoil characteristics after landslip erosion in dry hill country of New Zealand, and a test of the space-for-time hypothesis  

Microsoft Academic Search

The rate of development of topsoil is an important characteristic for soil resilience and sustainable use. We located a chronosequence (1–59 yr) of recovering landslip scars in erodible siltstone hill country under permanent pasture for sheep farming in New Zealand. We measured the rates of recovery in microbial C, respiration, catabolic diversity, phosphatase, sulphatase and invertase activities, pH, total C,

Graham Sparling; Des Ross; Noel Trustrum; Greg Arnold; Andrew West; Tom Speir; Louis Schipper

2003-01-01

257

Performance study of cementitious systems containing zeolite and silica fume: effects of four metal nitrates on the setting time, strength and leaching characteristics  

Microsoft Academic Search

The aim of this study is to investigate the effect of four metal nitrate contaminants, namely chromium, manganese, lead and zinc on the mechanical and leaching characteristics of cement-based materials. For this purpose, three different matrices made of: (i) Portland cement, (ii) Portland cement and silica fume, and (iii) Portland cement and natural zeolite were studied. The effects of metals

C Gervais; S. K Ouki

2002-01-01

258

Wastewater characteristics  

Microsoft Academic Search

Characterization of plant influent, effluent, and internal process streams provides plant operations personnel with the information they need to properly control treatment processes. To obtain that information, the operator should determine the characteristics of the raw wastewater and stream by collecting and analyzing representative samples throughout the plant. This paper gives a basic understanding of wastewater characteristics and sampling necessary

Samorn Muttamara

1996-01-01

259

A time-course study of behavioral and electrophysiological characteristics in a mouse model of different stages of Parkinson's disease using 6-hydroxydopamine.  

PubMed

Parkinson's disease (PD) is characterized by abnormal motor symptoms and increased neuronal activity in the subthalamic nucleus (STN) as the disease progresses. We investigated the behavioral and electrophysiological characteristics in a mouse model mimicking the progressive stages of human PD (early, moderate, and advanced) by injecting 6-hydroxydopamine (6-OHDA) into the right medial forebrain bundle (MFB) at three different concentrations (2, 4, and 6?g/2?l). Significant changes in motor symptoms were demonstrated between groups in association with relative TH-positive cell loss in the substantia nigra pars compacta (SNc). Moreover, electrophysiologically assessed changes in the mean neuronal firing rate in the STN neurons were comparable to those in the early to advanced stages of human PD. Thus, the mouse model presented herein replicates the unique characteristics of each progressive stage of PD, in both motor and neurophysiological aspects, and therefore can be useful for further investigations of PD pathology. PMID:25698596

Park, Sunghee Estelle; Song, Kang-Il; Suh, Jun-Kyo Francis; Hwang, Dosik; Youn, Inchan

2015-05-01

260

Effects of growth path, sire type, calving time and sex on growth and carcass characteristics of beef cattle in the agricultural area of Western Australia  

Microsoft Academic Search

Growth, carcass characteristics and meat quality of the steer and heifer progeny of autumn (AC: March-April) and winter (WC: June-July) calving cows following weaning in January in each of 3 years (2003-05) were measured. The cows were mated to sires with a high estimated breeding value for either retail beef yield (RBY), intramuscular fat (IMF) or both RBY and IMF.

B. L. McIntyreA; G. D. TudorA; D. ReadA; W. Smart; T. J. Della BoscaA; E. J. SpeijersA; B. OrchardA

2009-01-01

261

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

262

Active play and screen time in US children aged 4 to 11 years in relation to sociodemographic and weight status characteristics: a nationally representative cross-sectional analysis  

Microsoft Academic Search

BACKGROUND: The high prevalence of childhood obesity underscores the importance of monitoring population trends in children's activity and screen time, and describing associations with child age, gender, race\\/ethnicity, and weight status. Our objective was to estimate the proportion of young children in the US who have low levels of active play or high levels of screen time, or who have

Sarah E Anderson; Christina D Economos; Aviva Must

2008-01-01

263

The Effect of Beaver Activity on the Ammonium Uptake and Water Residence Time Characteristics of a Third-Order Stream Reach  

NASA Astrophysics Data System (ADS)

Increasing beaver populations within low gradient basins in the northeastern United States are fundamentally changing the way water and dissolved nutrients are exported through these stream networks to the coast. Beaver dams can increase water residence time and contact with organic material, promote anoxic conditions and enhance both surface and hyporheic transient storage; all of these may have an impact on biogeochemical reactivity and nutrient retention. To quantitatively assess some of these effects we co-injected NaCl and NH4+ into the same 3rd-order stream reach in Massachusetts, USA under pre- and post-dam conditions. These experiments were done at similar discharge rates to isolate the impacts of a large natural beaver dam (7 m X 1.3 m) on the low-gradient (0.002) system where variable discharge also imparts a strong control on residence time. During the post-dam experiment there was an estimated 2300 m3 of water impounded behind the structure, which influenced more than 300 m of the 650 m stream reach. Our results showed that median transport time through the reach increased by 160% after dam construction. Additionally the tracer tailing time normalized to the corresponding median transport time increased from 1.08 to 1.51, indicating a pronounced tailing of the tracer signal in the post-dam condition. Data collected within the beaver pond just upstream of the dam indicated poor mixing and the presence of preferential flow paths through the generally stagnant zone. The uptake length (Sw) for NH4+ was 1250 m under the pre-dam condition, and may have changed for the post-dam reach in part because of the observed changes in residence time. As beaver population growth continues within these basins the consequences may be a smoothing of the outlet hydrograph and increased nutrient and organic matter removal and storage along the stream network.

Briggs, M.; Gooseff, M. N.; Wollheim, W. M.; Peterson, B. J.; Morkeski, K.

2009-12-01

264

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. PMID:17202273

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

265

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

266

Determination of the correct migration time and other parameters of the Haarhoff-van der Linde function from the peak geometry characteristics.  

PubMed

For Gaussian peaks, the migration time of the analyte results as the position of the top of the peak and the zone variance is proportional to the peak width. Similar relations have not yet been derived for the Haarhoff-van der Linde (HVL) function, which appears as a fundamental peak-shape function in electrophoresis. We derive the relations between the geometrical measures of the HVL-shaped peak, that is the position of its maximum, its width and a measure of its asymmetry, and the respective parameters a1 , a2 , and a3 , of the corresponding HVL function. Under the condition of the HVL-shaped peak, the a1 parameter reflects the true migration time of the analyte, which may differ from the peak top position significantly. Our procedure allows us to express the parameters without the need of any external data processing (nonlinear regression). We demonstrate our approach on simulated peaks and on experimental data integrated by the ChemStation software (delivered with the CE instrumentation by Agilent Technologies). A significant improvement is achieved reading the migration time of the experimental and simulated peaks, which draws the error of the HVL-shaped peak migration time evaluation down to the resolution of the data sampling rate. PMID:25475400

Dubský, Pavel; Dvo?ák, Martin; M?llerová, Ludmila; Gaš, Bohuslav

2015-03-01

267

Amplitude-time characteristics of the long-latency components ( N 1, N 2, and P 300) of acoustic evoked potential in healthy subjects  

Microsoft Academic Search

The aim of the study was to trace the cumulative changes in the amplitude-time parameters of the AEP (acoustic evoked potential)\\u000a components N1, N2, and P300 in the experimental situations of different complexities (counting and listening to sounds) and to compare the differences\\u000a between young and mature subjects. The AEP was recorded in 12 healthy subjects aged 18 to 22

L. B. Oknina; O. A. Kuznetsova; A. P. Belostotskyi; N. L. Nechaeva; E. V. Kutakova; E. L. Masherow; A. S. Romanov

2011-01-01

268

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.

269

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

270

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

271

Resolving the EGF-EGFR interaction characteristics through a multiple-temperature, multiple-inhibitor, real-time interaction analysis approach  

PubMed Central

Overexpression and aberrant activity of the epidermal growth factor (EGF) have been observed in various cancer types, rendering it an important target in oncology research. The interaction between EGF and its receptor (EGFR), as well as subsequent internalization, is complex and may be affected by various factors including tyrosine kinase inhibitors (TKIs). By combining real-time binding curves produced in LigandTracer® with internalization assays conducted at different temperatures and with different TKIs, the processes of ligand binding, internalization and excretion was visualized. SKOV3 cells had a slower excretion rate compared to A431 and U343 cells, and the tested TKIs (gefitinib, lapatinib, AG1478 and erlotinib) reduced the degree of internalization. The kinetic analysis of the binding curves further demonstrated TKI-dependent balances of EGFR monomer and dimer populations, where lapatinib promoted the monomeric form, while the other TKIs induced dimers. The dimer levels were found to be associated with the apparent affinity of the EGF-EGFR interaction, with EGF binding stronger to EGFR dimers compared to monomers. This study analyzed how real-time molecular interaction analysis may be utilized in combination with perturbations in order to understand the kinetics of a ligand-receptor interaction, as well as some of its associated intracellular processes. Our multiple-temperature and -inhibitor assay setup renders it possible to follow the EGFR monomer, dimer and internalized populations in a detailed manner, allowing for a new perspective of the EGFR biology. PMID:24649173

BJÖRKELUND, HANNA; GEDDA, LARS; MALMQVIST, MAGNUS; ANDERSSON, KARL

2013-01-01

272

On some time, mass, energy and power characteristics of the interstellar flights in a one-step rocket. Can the kardashev-type of civilizations exist?  

NASA Astrophysics Data System (ADS)

By definition Kardashev-type civilizations, after learning to manage the energy of the star, can conquer large parts of the galaxy. Is this possible at all? In the present paper several types of interstellar flights are considered with different velocities v, different types of fuel: chemical, fission nuclear fuel, fusion nuclear fuel and antimatter fuel. The flight parameters for different exhaust velocities u measured relative to the center of mass of the interstellar rocket are also discussed. For thermal (chemical) propulsion u/c = 10 -5, for ion (nuclear) propulsion u/c = 10 -1 and for the photon (matter-antimatter annihilation) propulsion u/c = 1 . The following more advanced interstellar trips are analysed: (a) to the center of our Galaxy, Xa = 30.000 light years (l.y.). (b) to the nearest neighbouring galaxy Andromeda, Xb = 2.3 × 10 6 l.y., (c) to the frontiers of the visibility of the largest optical telescope, xc = 5 × 10 9 l.y. It follows from the above analysis that the realization of interstellar flights in one-step rocket is very improbable even to the nearest stars during the time comparable to the human life-time and even by the much more advanced civilization than that of our own.

Subotowicz, M.

273

Effects of blade tenderization, aging method and aging time on meat quality characteristics of Longissimus lumborum steaks from cull Holstein cows.  

PubMed

The effects of blade tenderization (BT), two aging methods (dry (D) and wet (W)), and aging time (2 and 23 d) on tenderness, color, and sensory properties of Longissimus lumborum muscles from 12 cull Holstein cows were evaluated. Dry-aged loins had higher combined trim and aging losses than control (C) for both D- and W-aging, mostly because of excess trim losses. BT steaks had WBSF of 33.13 N while C steaks had WBSF of 41.46 N (P=0.09). Aging decreased WBSF. Blade tenderized steaks had higher cook loss than C steaks. Aging, W-aging, and BT×W-aging improved myofibrillar (sensory) tenderness scores. Aging and/or BT improves sensory panel tenderness cull cow Longissimus lumborum steaks. Aging and blade tenderization combined can increase tenderness and value of Longissimus steaks from cull Holstein cows. PMID:24334044

Obuz, Ersel; Akkaya, Levent; Gök, Veli; Dikeman, Michael E

2014-03-01

274

A survey on time and frequency characteristics of induction motors with broken rotor bars in line-start and inverter-fed modes  

NASA Astrophysics Data System (ADS)

This paper deals with the comprehensive detailed concepts of the rotor broken bars fault in industrial induction motors. It reviews the most important and applicable techniques for fault detection, and addresses fault diagnosing procedures at different supply modes including line-start and inverter-fed modes. Moreover, new analytical and experimental aspects of fault are proposed using the time and frequency domain variations of the motor variables such as current, voltage, electromagnetic torque and speed. Since the faulty motor behavior cannot be correctly identified without considering the motor operating condition, and the capability of the previous fault indicators are studied deeply in order to investigate their applicability at different conditions. These conditions include various faults, load and reference speed levels and also fault location. All in all, a precise condition assessment of the rotor broken bar induction motors, suitable for industrial purposes, is presented considering motor supply and conditions changes.

Ghorbanian, Vahid; Faiz, Jawad

2015-03-01

275

Sentinel site-enhanced near-real time surveillance documenting West Nile virus circulation in two Culex mosquito species indicating different transmission characteristics, Djibouti City, Djibouti.  

PubMed

The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to investigate whether autochthonous WNV transmission occurs in the Djibouti City area, in how far, and which of, the endemic Culex mosquito species are involved in WNV circulation activity,and whether sentinel site-enhanced near-real time surveillance (SSE-NRTS) may increase WNV detection sensitivity, mosquito vector monitoring was conducted from January 2010 to June 2012. Six monitoring locations, including two identified sentinel sites, considered most probable for potential anthroponotic and zoonotic virus circulation activity, have been continuously employed. Among the 20431 mosquitoes collected, 19069 (93.4%) were Cx. quinquefasciatus, and 1345 (6.6%) Cx. pipiens ssp. torridus. WNV lineage 2 circulation activity was detected between December 20th, 2010 and January 7th, 2011. Overall, 19 WNV RNA-positive mosquito pools were detected. Generally, urban environment-specific WNV-RNA circulation took place in Cx. pipiens ssp. torridus, whereas periurban and rural area-linked circulation was detected only in Cx. quinquefasciatus. Serological investigation data from 10 volunteers employed at the dislocated zoonotic WNV transmission sentinel site suggest that six persons (60%) had an acute, or recent, WNV infection. Results show that WNV should be considered endemic for Djibouti and sentinel site-enhanced near-real time surveillance is an elegant and highly effective epidemiological tool. In Djibouti, the endemicity level, public health impact and transmission modes of vector-borne diseases in concordance with locally optimized monitoring and control regimen deserve further investigation. PMID:23214223

Faulde, Michael K; Spiesberger, Michael; Abbas, Babiker

2012-08-01

276

EMBEDDED PROTOSTARS IN THE DUST, ICE, AND GAS IN TIME (DIGIT) HERSCHEL KEY PROGRAM: CONTINUUM SEDs, AND AN INVENTORY OF CHARACTERISTIC FAR-INFRARED LINES FROM PACS SPECTROSCOPY  

SciTech Connect

We present 50-210 {mu}m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 {mu}m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H{sub 2}O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 {yields} 13 up to J = 40 {yields} 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 {mu}m [O I] flux ratio is 17.2 {+-} 9.2. The [O I] 63 {mu}m line correlates with L{sub bol}, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L{sub bol} increased by 1.25 (1.06) and T{sub bol} decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ( = (0.70 {+-} 1.12) x 10{sup 49} total particles). N{sub CO} correlates strongly with L{sub bol}, but neither T{sub rot} nor N{sub CO}(warm)/N{sub CO}(hot) correlates with L{sub bol}, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H{sub 2}O ( = 194 +/- 85 K) and OH ( = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines.

Green, Joel D.; Evans, Neal J. II; Rascati, Michelle R. [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Jorgensen, Jes K.; Dionatos, Odysseas; Lindberg, Johan E. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Kristensen, Lars E.; Yildiz, Umut A.; Van Kempen, Tim A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Salyk, Colette [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Meeus, Gwendolyn [Dpt. Fisica Teorica, Universidad Autonoma de Madrid, Campus Cantoblanco, E-28049 Madrid (Spain); Bouwman, Jeroen [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Visser, Ruud; Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Van Dishoeck, Ewine F.; Karska, Agata; Fedele, Davide [Max-Planck Institute for Extraterrestrial Physics, Postfach 1312, D-85741 Garching (Germany); Dunham, Michael M., E-mail: joel@astro.as.utexas.edu [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Collaboration: DIGIT Team1

2013-06-20

277

Comparison of the Detection Characteristics of Trace Species Using Laser-Induced Breakdown Spectroscopy and Laser Breakdown Time-of-Flight Mass Spectrometry.  

PubMed

The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS) and laser breakdown time-of-flight mass spectrometry (LB-TOFMS). Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application. PMID:25769051

Wang, Zhenzhen; Deguchi, Yoshihiro; Yan, Junjie; Liu, Jiping

2015-01-01

278

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

279

Real time quantification of low temperature radiofrequency ablation lesion size using phased array intracardiac echocardiography in the canine model: comparison of two dimensional images with pathological lesion characteristics  

PubMed Central

Objective: To evaluate the feasibility of quantifying low temperature radiofrequency catheter ablation (RFCA) lesions using a phased array intracardiac echocardiography (ICE) catheter—with better tissue penetration and in a deflectable device—in the canine model. Intervention: Low temperature radiofrequency (RF) energy (50–60°C at up to 40 W) was delivered to the left ventricle in 11 beagles for 60 seconds, using an 8 French catheter with a deflectable tip and a 4 mm distal electrode. Main outcome measures: Comparison of the width and depth of RFCA lesions measured by ICE with pathological findings. Results: 33 RF energies were delivered in 11 dogs. 31 lesions (94%) were confirmed at necropsy. 27 of 31 ablation lesions (87%) were detected by ICE. The mean (SD) width and depth of the ICE detected lesions were 10.4 (2.6) mm and 5.7 (1.9) mm, respectively. Pathological findings showed that RFCA lesions consisted of inner and outer layers. Macroscopically, the mean (SD) width and depth of the inner layers were 7.6 (2.3) mm and 3.6 (1.2) mm and those for the whole layers were 10.0 (2.8) mm and 5.3 (1.5) mm, respectively. Microscopically, the inner and outer layers corresponded to necrotic and oedematous areas, respectively. The ICE detected lesion size had better correlation with the pathological measurements of the whole layers in width (r = 0.911) and in depth (r = 0.756). Conclusion: The real time evaluation of RFCA lesion size using the phased array ICE is feasible, even with a low temperature RF application. However, ICE slightly overestimates RFCA lesion size compared with pathological necrotic lesion size. PMID:12860873

Doi, A; Takagi, M; Toda, I; Teragaki, M; Yoshiyama, M; Takeuchi, K; Yoshikawa, J

2003-01-01

280

Impact of co-morbidities and patient characteristics on international normalized ratio control over time in patients with nonvalvular atrial fibrillation.  

PubMed

This study determined the association between co-morbidities, including heart failure (HF) and time in therapeutic range (TTR), in patients with nonvalvular atrial fibrillation. Longitudinal patient-level anticoagulation management records collected from 2006 to 2010 were analyzed. Adult patients with nonvalvular atrial fibrillation who used warfarin for a 12-month period with no gap of >60 days between visits were identified. TTR <55% was defined as "lower" TTR. CHADS? score of ?2 was defined as "higher" CHADS?. Logistic regression analyses were conducted to determine the association between co-morbidities and TTR. A total of 23,425 patients met the study criteria. The mean age ± SD was 74.8 ± 9.7 years, with 84.8% aged ?65 years. The most common co-morbidities were hypertension (41.7%), diabetes (24.1%), HF (11.7%), and previous stroke (11.1%). The mean TTR ± SD was 67.3 ± 14.4%, with 18.6% of patients in the lower TTR range. In multivariate analyses using age, gender, hypertension, diabetes, stroke, and region as covariates, HF (adjusted odds ratio [OR] 1.41, 95% confidence interval [CI] 1.28 to 1.56; p <0.001), diabetes (OR 1.28, 95% CI 1.19 to 1.38; p <0.001), and previous stroke (OR 1.15, 95% CI 1.04 to 1.27; p <0.001) were associated with lower TTR. In a second set of multivariate analyses using gender and region as covariates, a higher CHADS? score was associated with lower TTR (OR 1.11, 95% CI 1.04 to 1.18; p <0.001). In conclusion, HF was associated with the greatest likelihood of a lower TTR, followed by diabetes, then stroke. Anticoagulation control may be more challenging for patients with these conditions. PMID:23800552

Nelson, Winnie W; Choi, Jiyoon C; Vanderpoel, Julie; Damaraju, Chandrasekharra V; Wildgoose, Peter; Fields, Larry E; Schein, Jeffrey R

2013-08-15

281

Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics.  

ERIC Educational Resources Information Center

Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

Denoyer, Eric; And Others

1982-01-01

282

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

283

Seasonal characteristics of fine particulate matter (PM) based on high resolution time-of-flight aerosol mass spectrometric (HR-ToF-AMS) measurements at the HKUST Supersite in Hong Kong  

NASA Astrophysics Data System (ADS)

Atmospheric particulate matter (PM) remains poorly understood due to the lack of comprehensive measurements at high time resolution for tracking its dynamic features and the lack of long-term observation for tracking its seasonal variability. Here, we present highly time-resolved and seasonal compositions and characteristics of non-refractory components in PM with diameter less than 1 ?m (NR-PM1) at a suburban site in Hong Kong. The measurements were made with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) at the Hong Kong University of Science and Technology (HKUST) Air Quality Research Supersite for four months, with one in each season of the year. The average NR-PM1 concentration of ~15 ?g m-3 is higher than those AMS measurements made in South Korea and Japan, but lower than those in North China, the Yangtze River Delta and the nearby Pearl River Delta. The seasonal dependence of the total NR-PM1 monthly averaged concentrations was small but that of the fractions of the species in NR-PM1 was significant. Site characteristic plays an important role in the relative fractions of species in NR-PM1 and our results are generally consistent with measurements at other non-urban sites in this regard. Detailed analyses were conducted on the AMS data in the aspects of (1) species concentrations, (2) size distributions, (3) degree of oxygenation of organics, and (4) positive matrix factorization (PMF)-resolved organic factors in a seasonal context, as well as with air mass origin from back-trajectory analysis. Sulfate had the highest fraction in NR-PM1 (> 40%) and the surrogates of secondary organic species, semi-volatile oxygenated organic aerosol (SVOOA) and low-volatility oxygenated organic aerosol (LVOOA), prevailed (~80%) in the organic portion of NR-PM1. Local contributions to the organic portion of NR-PM1 at this suburban site was strongly dependent on season. The hydrocarbon-like organic aerosol (HOA) factor related to local traffic emissions contributed > 10% to organic aerosols in spring and summer, but only 6-7% in autumn and winter. The cooking organic aerosol (COA) factor contributed > 10% to organic aerosols in winter. With the aid of highly time-resolved data, diurnal patterns of the degree of oxygenation of organic aerosols were used to determine the sources and formation processes of the least understood organic portion of PM. The oxygen-to-carbon atomic ratio (O : C) and average carbon oxidation state (OSC) showed little variation in autumn and winter when the long-range transport of oxidized organics dominated, whereas they peaked in the afternoon in spring and summer when locally produced secondary organic aerosol prevailed. Air mass origin, in contrast, had a strong influence on both NR-PM1 concentrations and the fractions of species in NR-PM1. The findings of the current study provide a better understanding of the role of air mass origin in the seasonal characteristics of the PM composition and the relative importance of local vs. transported organic aerosols in this region.

Li, Y. J.; Lee, B. P.; Su, L.; Fung, J. C. H.; Chan, C. K.

2014-08-01

284

Seasonal characteristics of fine particulate matter (PM) based on high-resolution time-of-flight aerosol mass spectrometric (HR-ToF-AMS) measurements at the HKUST Supersite in Hong Kong  

NASA Astrophysics Data System (ADS)

Atmospheric particulate matter (PM) remains poorly understood due to the lack of comprehensive measurements at high time resolution for tracking its dynamic features and the lack of long-term observation for tracking its seasonal variability. Here, we present highly time-resolved and seasonal compositions and characteristics of non-refractory components in PM with a diameter less than 1 ?m (NR-PM1) at a suburban site in Hong Kong. The measurements were made with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) at the Hong Kong University of Science and Technology (HKUST) Air Quality Research Supersite for 4 months, with one in each season of the year. The average NR-PM1 concentration of ~ 15 ?g m-3 is higher than those AMS measurements made in South Korea and Japan, but lower than those in North China, the Yangtze River Delta and the nearby Pearl River Delta. The seasonal dependence of the total NR-PM1 monthly averaged concentrations was small, but that of the fractions of the species in NR-PM1 was significant. Site characteristic plays an important role in the relative fractions of species in NR-PM1 and our results are generally consistent with measurements at other non-urban sites in this regard. Detailed analyses were conducted on the AMS data in the aspects of (1) species concentrations, (2) size distributions, (3) degree of oxygenation of organics, and (4) positive matrix factorization (PMF)-resolved organic factors in a seasonal context, as well as with air mass origin from back-trajectory analysis. Sulfate had the highest fraction in NR-PM1 (> 40%), and the surrogates of secondary organic species - semi-volatile oxygenated organic aerosol (SVOOA) and low-volatility oxygenated organic aerosol (LVOOA) - prevailed (~ 80%) in the organic portion of NR-PM1. Local contributions to the organic portion of NR-PM1 at this suburban site was strongly dependent on season. The hydrocarbon-like organic aerosol (HOA) factor related to local traffic emissions contributed > 10% to organic aerosols in spring and summer but only 6-7% in autumn and winter. The cooking organic aerosol (COA) factor contributed > 10% to organic aerosols in winter. With the aid of highly time-resolved data, diurnal patterns of the degree of oxygenation of organic aerosols were used to determine the sources and formation processes of the least understood organic portion of PM. The oxygen-to-carbon atomic ratio (O : C) and average carbon oxidation state OS C) showed little variation in autumn and winter, when the long-range transport of oxidized organics dominated, whereas they peaked in the afternoon in spring and summer, when locally produced secondary organic aerosol prevailed. Air mass origin, in contrast, had a strong influence on both NR-PM1 concentrations and the fractions of species in NR-PM1. The findings of the current study provide a better understanding of the role of air mass origin in the seasonal characteristics of the PM composition and the relative importance of local vs. transported organic aerosols in this region.

Li, Y. J.; Lee, B. P.; Su, L.; Fung, J. C. H.; Chan, C. K.

2015-01-01

285

GEOLOGICAL CHARACTERISTICS  

E-print Network

CAPSULE DESCRIPTION: Ilmenite, hemo-ilmenite or titaniferous magnetite accumulations as cross-cutting lenses or dike-like bodies, Ia> ers or disseminations within anorthositiclgabbroicinoritic rocks. These deposits can be subdivided into an ilmenite subtype (anorthosite-hosted titanium-iron) and a titaniferous magnetite subtype (gabbro-anorthosite-hosted iron-titanium). TECTONIC SETTING: Commonly associated with anorthosite-gabbro-norite-monzonite (mangerite)charnockite granite (AMCG) suites that are conventionally interpreted to be anorogenic and/or extensional. Some of the iron-titanium deposits occur at continental margins related to island arc magmatism followed by an episode of erogenic compression. DEPOSITIONAL ENVIRONMENT i GEOLOGICAL SETTING: Deposits occur in intrusive complexes which typically are emplaced at deeper levels in the crust. Progressive differentiation of liquids residual from anorthosite-norite magmas leads to late stage intrusions enriched in Fe and Ti oxides and apatite. AGE OF MINERALIZATION: Mainly Mesoproterozoic (1.65 to 0.90 Ga) for the ihnenite deposits, but this may be a consequence of a particular combination of tectonic circumstances, rather than any a priori temporal control. The Fe-Ti deposits with titaniferous magnetite do not appear to be restricted in time. HOST/ASSOCIATED ROCKS: Hosted by massive, layered or zoned intrusive complexes- anorthosite, norite,

G. A. Gross; C. F. Gower; D. V. Lefebure; Commodities (byproducts) Ti

286

The wind characteristics program  

NASA Astrophysics Data System (ADS)

Wind characteristics research activities emphasize wind resource assessment, site selection and evaluation techniques, and wind characteristics for wind turbine design, performance and operations evaluation. Wind resource analysis shows the greatest area of high wind power resource is in the midsection of the U.S. High wind power is available in other sections of the country and is described in some detail on a state by state basis in twelve regional atlases. To carry the wind prospecting process to a finer scale, site selection techniques for small and large wind turbines were developed, tested, and documented. There is a broad range of sophistication and reliability in these techniques and their application must be matched with the priorities and time available for energy planning efforts. The nature of wind gustiness was evaluated statistically and modeled for calculating fatigue cycles and extreme events.

Wendell, L. L.

287

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

288

[A secondary discussion on acupoint characteristic].  

PubMed

With references of historical materials and modern literature regarding acupoint characteristic, a secondary analysis on the concept, origin, related factors and research methods in present research of acupoint characteristic is performed. The acupoint characteristic should be considered as an acupoint inherent attribute that could explain physiological and pathological manifestations at the same time, including location attribute and function attribute, which is related with time and treatment method. Some re-thinking on acupoint characteristic is proposed as well as advice on further research method and direction, hoping to promote the research development of acupoint characteristic. PMID:25112091

Niu, Jian-Fei; Zhao, Xiao-Feng; Wu, Lian-Zhong; Shi, Xue-Min

2014-06-01

289

Predictors of delay discounting among smokers: Education level and a Utility Measure of Cigarette Reinforcement Efficacy are better predictors than demographics, smoking characteristics, executive functioning, impulsivity, or time perception.  

PubMed

Ninety-four smokers completed the delay discounting procedure for either hypothetical amounts of money, $10 (money) and $1000 (money) or hypothetical amounts of cigarettes ($10 and $1000 worth of cigarettes). We investigated how variables previously found to be related to rates of delay discounting accounted for the observed results. These variables included the following: demographic information, smoking characteristics, executive function abilities, impulsivity, time perception, and the Utility Measure of Cigarette Reinforcing Efficacy (UMCE). Education level and UMCE were each significantly correlated with 3 out of 4 of the discounting measures. Moreover, the largest effect sizes observed were between these two measures and the four discounting measures. All potential discounting predictors were also investigated using step-wise linear regression with Bayesian Information Criterion (BIC) analysis - these BIC models revealed that education level and UMCE accounted for large portions of the variance. We conclude that education level and UMCE were the most consistent predictors of discounting. This data is discussed within the framework of a widely accepted neuroeconomic model that suggests that two brain systems separately assess two separate facets of decision-making, and the interplay between these two systems determines self-control in smokers. We hypothesize that education level and UMCE may serve as surrogate measures of the functionality of these two systems and that discounting may be a sentinel measure of self-control. PMID:25661991

George Wilson, A; Franck, Christopher T; Terry Mueller, E; Landes, Reid D; Kowal, Benjamin P; Yi, Richard; Bickel, Warren K

2015-06-01

290

Bayesian estimation of test characteristics of real-time PCR, bacteriological culture and California mastitis test for diagnosis of intramammary infections with Staphylococcus aureus in dairy cattle at routine milk recordings.  

PubMed

Danish farmers can order a real-time PCR mastitis diagnostic test on routinely taken cow-level samples from milk recordings. Validation of its performance in comparison to conventional mastitis diagnostics under field conditions is essential for efficient control of intramammary infections (IMI) with Staphylococcus aureus (S. aureus). Therefore, the objective of this study was to estimate the sensitivity (Se) and specificity (Sp) of real-time PCR, bacterial culture (BC) and California mastitis test (CMT) for the diagnosis of the naturally occurring IMI with S. aureus in routinely collected milk samples using latent class analysis (LCA) to avoid the assumption of a perfect reference test. Using systematic random sampling, a total of 609 lactating dairy cows were selected from 6 dairy herds with bulk tank milk PCR cycle threshold (Ct) value ?39 for S. aureus. At routine milk recordings, automatically obtained cow-level (composite) milk samples were analyzed by PCR and at the same milking, 2436 quarter milk samples were collected aseptically for BC and CMT. Results showed that 140 cows (23%) were positive for S. aureus IMI by BC while 170 cows (28%) were positive by PCR. Estimates of Se and Sp for PCR were higher than test estimates of BC and CMT. SeCMT was higher than SeBC however, SpBC was higher than SpCMT. SePCR was 91%, while SeBC was 53%, and SeCMT was 61%. SpPCR was 99%, while SpBC was 89%, and SpCMT was 65%. In conclusion, PCR has a higher performance than the conventional diagnostic tests (BC and CMT) suggesting its usefulness as a routine test for accurate diagnosis of S. aureus IMI from dairy cows at routine milk recordings. The use of LCA provided estimates of the test characteristics for two currently diagnostic tests (BC, CMT) and a novel technique (real-time PCR) for diagnosing S. aureus IMI under field conditions at routine milk recordings in Denmark. PMID:23992955

Mahmmod, Yasser S; Toft, Nils; Katholm, Jørgen; Grønbæk, Carsten; Klaas, Ilka C

2013-11-01

291

Optical characteristics of lightning  

NASA Technical Reports Server (NTRS)

A study of the optical characteristics of cloud-to-ground dischargers and how they compare with intracloud flashes was completed. Time resolved optical (7774A) and electric field-change waveforms were measured above clouds from a U2 airplane coincident with ground-based measurements of lightning. The optical pulse trains are studied for within and between flash variability. Specifically, for each flash researchers examine the 10, 50 (full width half maximum), and 90 percent pulse widths; the 10-10, 10-50, 10-90, and 10-peak percent amplitude rise times; the radiances (optical power densities); radiant energy densities; and pulse intervals. The optical pulse characteristics of first strokes, subsequent strokes, the intracloud components of cloud-to-ground flashes and intracloud flashes as viewed from above cloud are shown to exhibit very similar waveshapes, radiances and radiant energy densities. Descriptive statistics on these pulse categories were tabulated for 25 visually confirmed cloud-to-ground flashes (229 optical pulses) and 232 intracloud flashes (3126 optical pulses). A companion study of lightning observations above and below cloud in storms, storm complexes, and mesoscale convective systems has also been completed. Researchers compared the mapping of total lightning activity from above clouds with ground-based measurements and storm evolution. Although the total (IC + CG) lightning activity is the more representative indication of thunderstorm growth and decay, the ground strike data can be used to locate, diagnose, and track storm evolution in a number of instances.

Goodman, S. J.

1985-01-01

292

Characteristics of Male Alcohol Offenders.  

ERIC Educational Resources Information Center

Because most studies investigating psychological profiles of subjects convicted of driving under the influence of alcohol (DUI) have been conducted at the time of arrest or treatment, it is unclear whether subjects' anxiety, depression, and hostility represent "trait" characteristics central to alcohol abuse or "state" responses to arrest and…

Ratliff, Katharine G.; Ellis, Thomas E.

293

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

294

Seasonal vegetation characteristics of the United States  

Microsoft Academic Search

The U.S. Geological Survey's EROS Data Center has created a prototype 1?km resolution data base of vegetation seasonal characteristics. The characteristics are derived from time?series NDVI data collected by the AVHRR satellite sensor. Information covering the 5 years 1989–1993 is included in the data base. Although quantitative validation of the seasonal characteristics cannot be made until several evaluation efforts are

Bradley C. Reed; Limin Yang

1997-01-01

295

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

296

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

297

Exploring Lightning Jump Characteristics  

NASA Technical Reports Server (NTRS)

This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to higher Maximum Expected Size of Hail, Vertical Integrated Liquid and lightning flash rates (area-normalized) than the clusters that did not exhibit any LJ (LJ0). The respective mean values for LJ1 (LJ0) clusters are 80 min (35 min), 14 mm (8 mm), 25 kg per square meter (18 kg per square meter) and 0.05 flash per min per square kilometer (0.01 flash per min per square kilometer). Furthermore, the LJ1 clusters are also characterized by slower decaying autocorrelation functions, a result that implies a less "random" behavior in the temporal flash rate evolution. In addition, the temporal occurrence of the last LJ provides an estimate of the time remaining to the storm's dissipation. Depending of the LJ strength (i.e., varying thresholds), these values typically range between 20-60 min, with stronger jumps indicating more time until storm decay. This study's results support the hypothesis that the LJ is a proxy for the storm's kinematic and microphysical state rather than a coincidental value.

Chronis, Themis; Carey, Larry D.; Schultz, Christopher J.; Schultz, Elise; Calhoun, Kristin; Goodman, Steven J.

2014-01-01

298

Characteristic sounds facilitate visual search.  

PubMed

In a natural environment, objects that we look for often make characteristic sounds. A hiding cat may meow, or the keys in the cluttered drawer may jingle when moved. Using a visual search paradigm, we demonstrated that characteristic sounds facilitated visual localization of objects, even when the sounds carried no location information. For example, finding a cat was faster when participants heard a meow sound. In contrast, sounds had no effect when participants searched for names rather than pictures of objects. For example, hearing "meow" did not facilitate localization of the word cat. These results suggest that characteristic sounds cross-modally enhance visual (rather than conceptual) processing of the corresponding objects. Our behavioral demonstration of object-based cross-modal enhancement complements the extensive literature on space-based cross-modal interactions. When looking for your keys next time, you might want to play jingling sounds. PMID:18567253

Iordanescu, Lucica; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

2008-06-01

299

Switching Characteristics of Ferroelectric Transistor Inverters  

NASA Technical Reports Server (NTRS)

This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

2010-01-01

300

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

301

Characteristics and mechanisms of electrorheological fluids  

Microsoft Academic Search

Electrorheological (ER) fluids consist of suspensions of fine polarizable particles in a dielectric medium, which upon application of an electric field take on the characteristics of a solid in times of the order of milliseconds and reversibly return to liquid behavior upon removal of the field. The rheology, electrical characteristics, and structure of typical ER fluids are here reviewed. The

Hans Conrad; Arnold F. Sprecher

1991-01-01

302

Fetal Alcohol Syndrome: Characteristics, Prevention, Treatment and Long Term Outlook.  

ERIC Educational Resources Information Center

This article discusses fetal alcohol syndrome (FAS) including causes, common characteristics, secondary characteristics, prevention, and treatment. Economic implications are noted which suggest that treatment costs are 100 times the cost of prevention programs. (DB)

Seward, Cynthia A.; Barber, William H.

1991-01-01

303

Real-time imaging  

Microsoft Academic Search

Real-time imaging systems are a special class that underlies important application domains that include industrial, medical and military. The main characteristic of a real-time imaging system is the need for deadline satisfaction. Admittedly, this definition is very broad and vague. The case can be made that every system is real-time. In a \\

P. A. Laplante

2005-01-01

304

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.

National Security Agency Central Security Service

2009-04-22

305

Characteristic Evolution and Matching  

E-print Network

I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black spacetime. A prime application of characteristic evolution is to compute waveforms via Cauchy-characteristic matching, which is also reviewed.

Jeffrey Winicour

2005-12-08

306

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

307

Bluetooth energy characteristics in wireless sensor networks  

Microsoft Academic Search

In this paper a measurement system to create an experimental model and a tool box for simulations concerning both the energy consumption and the time aspect when creating wireless sensor networks using Bluetooth 2.0 + enhanced data rate has been developed. Further energy and time characteristics for critical events when using Bluetooth 2.0 in wireless sensor networks are investigated experimentally,

M. Blom; M. Ekstrom; J. G. Castano; M. Linden

2008-01-01

308

PressurePressure Indiana Coal Characteristics  

E-print Network

TimeTime PressurePressure · Indiana Coal Characteristics · Indiana Coals for Coke · CoalTransportation in Indiana · Coal Slurry Ponds Evaluation · Site Selection for Coal Gasification · Coal-To-Liquids Study, CTL · Indiana Coal Forecasting · Under-Ground Coal Gasification · Benefits of Oxyfuel Combustion · Economic

Fernández-Juricic, Esteban

309

Characteristic Evolution and Matching  

E-print Network

I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress in characteristic evolution is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black hole spacetime. Cauchy codes have now been successful at simulating all aspects of the binary black hole problem inside an artificially constructed outer boundary. A prime application of characteristic evolution is to extend such simulations to null infinity where the waveform from the binary inspiral and merger can be unambiguously computed. This has now been accomplished by Cauchy-characteristic extraction, where data for the characteristic evolution is supplied by Cauchy data on an extraction worldtube inside the artificial outer boundary. The ultimate application of characteristic evolution is to eliminate the role of this outer boundary by constructing a global solution via Cauchy-characteristic matching. Progress in this direction is discussed.

Jeffrey Winicour

2012-01-12

310

Aircraft compass characteristics  

NASA Technical Reports Server (NTRS)

A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Characteristics of Navy aircraft compasses IV to IX and some other compasses are shown for the range of temperatures experienced in flight. Results of flight tests are presented. These results indicate that the characteristic most desired in a steering compass is a short period and, in a check compass, a low overswing.

Peterson, John B; Smith, Clyde W

1937-01-01

311

Observation of a metal-to-insulator transition with both Mott-Hubbard and Slater characteristics in Sr2IrO4 from time-resolved photocarrier dynamics  

E-print Network

We perform a time-resolved optical study of Sr[subscript 2]IrO[subscript 4] to understand the influence of magnetic ordering on the low energy electronic structure of a strongly spin-orbit coupled J[subscript eff] = 1/2 ...

Hsieh, David

312

A high performance liquid chromatography fingerprinting and ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry chemical profiling approach to rapidly find characteristic chemical markers for quality evaluation of dispensing granules, a case study on Chuanxiong Rhizoma.  

PubMed

A high performance liquid chromatography-photodiode array detector (HPLC-PDA) fingerprinting and ultra high performance liquid chromatography-photodiode array detector coupled with quadrupole time-of-flight mass spectrometry (UHPLC-PDA-QTOF-MS/MS) based chemical profiling approach was developed to rapidly find characteristic chemical markers for quality control of dispensing granules, taking Chuanxiong Rhizoma (CR) as a model herb. Firstly, CR crude drugs, their traditional decoctions and CR dispensing granules were analyzed by HPLC-PDA to rapidly establish the fingerprints and thereby generate the simulative median chromatograms of CR crude drugs, decoctions and dispensing granules, and by comparing the simulative median chromatograms, major characteristic peaks of CR decoctions and dispensing granules could be determined. Secondary, UHPLC-PDA-QTOF-MS/MS was used to identify the major characteristic peaks of CR decoctions and dispensing granules. The identities of three major peaks were elucidated and confirmed to be ferulic acid (1), senkyunolide I (2) and senkyunolide H (3) by comparing the mass/UV spectra and retention times with that of the reference compounds. Thirdly, an HPLC-PDA method was validated to quantify the three characteristic components in commercial CR dispensing granules. The average contents of ferulic acid and senkyunolide H were found to be less than 1.0mg/g, whereas that of senkyunolide I was 4.40mg/g in CR dispensing granules, which indicated that senkyunolide I might be chosen as a suitable quantitative marker, while ferulic acid and senkyunolide H as qualitative markers for the quality evaluation of CR dispensing granules. It is suggested that this newly established approach could be used to practically and rapidly find suitable marker compounds for quality control of dispensing granules derived from other medicinal herbs. PMID:24176743

Zhang, Xiao-Lin; Liu, Li-Fang; Zhu, Ling-Ying; Bai, Ying-Jia; Mao, Qian; Li, Song-Lin; Chen, Shi-Lin; Xu, Hong-Xi

2014-01-01

313

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 ...

314

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

315

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

316

Patient characteristics and fairness  

Microsoft Academic Search

This study examines the fairness concept of health care professionals, and asks whether they are willing to use a patient’s\\u000a age and other potential fairness characteristics rather than health benefits as relevant arguments in the allocation of health\\u000a care resources? The patient characteristics in the health care professionals’ survey encompass age, productivity and lifestyle.\\u000a The study is a replication of

Hannu Valtonen

2009-01-01

317

A Characteristic Particle Length  

E-print Network

It is argued that there are characteristic intervals associated with any particle that can be derived without reference to the speed of light $c$. Such intervals are inferred from zeros of wavefunctions which are solutions to the Schr\\"odinger equation. The characteristic length is $\\ell=\\beta^2\\hbar^2/(8Gm^3)$, where $\\beta=3.8\\dots$; this length might lead to observational effects on objects the size of a virus.

Mark D. Roberts

2014-06-14

318

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

319

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

320

A modified berman model for the prediction of time-dependent dielectric breakdown (TDDB) characteristics of low-k\\/ULK interconnect dielectrics from dual-voltage ramp dielectric breakdown (DVRDB) test  

Microsoft Academic Search

We present a modified Berman model that relates breakdown voltage distributions, from dual voltage ramp dielectric breakdown (DVRDB) test, to the distribution of time-to-fail (TTF) during constant voltage stress (CVS) conditions, assuming that dielectric failure behavior under a constant voltage stress follows the square-root E-model. The methodology presented in this work demonstrates a fast and very effective way of extracting

Tae-Young Jeong; Seunghee Oh; Miji Lee; Seungman Choi; A. T. Kim

2010-01-01

321

Hydrodynamic characteristics of UASB bioreactors.  

PubMed

The hydrodynamic characteristics of UASB bioreactors operated under different organic loading and hydraulic loading rates were studied, using three laboratory scale models treating concocted sucrose wastewater. Residence time distribution (RTD) analysis using dispersion model and tanks-in-series model was directed towards the characterization of the fluid flow pattern in the reactors and correlation of the hydraulic regime with the biomass content and biogas production. Empty bed reactors followed a plug flow pattern and the flow pattern changed to a large dispersion mixing with biomass and gas production. Effect of increase in gas production on the overall hydraulics was insignificant. PMID:23505813

John, Siby; Tare, Vinod

2011-10-01

322

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

323

Commercial Buildings Characteristics, 1992  

SciTech Connect

Commercial Buildings Characteristics 1992 presents statistics about the number, type, and size of commercial buildings in the United States as well as their energy-related characteristics. These data are collected in the Commercial Buildings Energy Consumption Survey (CBECS), a national survey of buildings in the commercial sector. The 1992 CBECS is the fifth in a series conducted since 1979 by the Energy Information Administration. Approximately 6,600 commercial buildings were surveyed, representing the characteristics and energy consumption of 4.8 million commercial buildings and 67.9 billion square feet of commercial floorspace nationwide. Overall, the amount of commercial floorspace in the United States increased an average of 2.4 percent annually between 1989 and 1992, while the number of commercial buildings increased an average of 2.0 percent annually.

Not Available

1994-04-29

324

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

325

Amplitude and correlation of environmental signals in solid precipitation, surface snow and deep ice core at Dome Fuji, Antarctica - Characteristics of climate and environmental signals with the various time scales -  

NASA Astrophysics Data System (ADS)

Two deep ice cores (DF1: 2503m, DF2: 3035m) at Dome Fuji, Antarctica have the in-depth information on 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+, Mg2+, Ca2+, dD, d18O, d-excess, dust. Generally, 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. Especially, warming events (AIM, inter-glacial stage) are studied with different time scale. Time scales of our studies are daily, yearly, decadal, few hundred and millennial-scales and glacial-interglacial cycle. Deep ice core records are compared with initial conditions (precipitation and surface snow). We show the difference of the chemistry of surface snow by the difference of the snow type in the same area. The amplitude of the variation of the signal becomes small from surface snow to ice. The average value of snow is inter-glacial stage level. By the way, the concentration of nitrate decreased from the snow surface as you know. Calcium and nitrate has no correlation in surface snow but they have a strong correlation in the ice core.

Motoyama, H.

2013-12-01

326

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. PMID:24936013

Braun, S.; Scheichl, S.

2014-01-01

327

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

328

High resolution 3-D imaging for characteristics of (111)-oriented Pb(Zr0.35Ti0.65)O3 thin film by using time-of-flight secondary ion mass spectrometry and piezoresponse force microscopy  

NASA Astrophysics Data System (ADS)

The properties of Pb(Zr0.35Ti0.65)O3 (PZT) thin films, ˜150-nm thick, deposited on an electrode Pt (111)/Ti layer and an SiO2/Si (100) substrate using a chemical sol-gel solution deposition method were investigated by using the high resolution X-ray diffraction (HR-XRD), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and piezoresponse force microscopy (PFM) systems. The in-plane orientations of crystal phase for the PZT film were confirmed with a 3-D pole-figure measurement method. The degree of the c-axis orientation was also measured by 2 ?-w scans and a scan (rocking-curve) measurement. Through 2D and 3D images by TOF-SIMS, we could confirm visually the concentration distribution for the surface and diffusion status to depth direction. Through atomic force microscopy (AFM) techniques, the grain profiles in the local area were characterized in detail. The 3-D images of the phase and magnitude for the polarization behavior along the applying electric field were displayed by using PFM techniques.

Shin, Hyun-Chang; Song, Joon-Tae

2011-09-01

329

Personal Characteristics. Career Guidance.  

ERIC Educational Resources Information Center

Materials contained in this career guidance unit are designed to direct the attention of the senior high school student to five types of personal characteristics to facilitate a more realistic career exploration: abilities, interests, values, physical traits, and personal and social behavior. The two- to three-hour unit contains self-instruction,…

Mesa Public Schools, AZ.

330

Malting Barley Characteristics  

E-print Network

Malting Barley Characteristics for Craft Brewers Executive Summary The brewing industry is evolving.S. brewing industry is currently undergoing profound and lasting structural change. Craft brewers for a growing brewing Industry. Nonetheless, prior to the advent of craft brewery companies in the late 1970s

331

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.

332

Life Mode Characteristics  

NSDL National Science Digital Library

This exercise provides a standardized format that can be used to describe the life mode and its characteristics for most any organism or group of organisms. This format is used (reinforced) in many other exercises as the context for comparing and contrasting clades within and among systematic groups. The classification also provides a context for discussing patterns and trends in evolution and ecology.

Steve Hageman

333

Employment Characteristics of Families  

NSDL National Science Digital Library

The Bureau of Labor Statistics site offers data on the employment characteristics of American families. The statistics include data on employment and unemployment in families by race, relationship, sex, marital status, presence of children in the family, and presence of children under three, among others. The data can be accessed from a table of contents or reviewed in an extensive news release.

334

Telling Time  

NSDL National Science Digital Library

Lets practice telling time! Practice with the dragon to tell time. Dragon Telling Time How long does it take you to tell time?Stop the Clock! Can you set the correct time? Try it here! Setting the correct time ...

Ms. Berman

2008-11-12

335

Adult Learner Characteristics and Instructional Objectives.  

ERIC Educational Resources Information Center

Using 40 male and 40 female part time learners with an average age of 36.6, this program planning study explored relationships between selected learner characteristics and behaviorally stated cognitive instructional objectives (IOs). Variables included age, sex, socioeconomic status, verbal ability, and a measure of learners' goals or learning…

Etter, David Campbell George

336

Characteristic impedance of unbalanced TDR probes  

Microsoft Academic Search

Time domain reflectometry (TDR) may be used to make simultaneous measurements of both dielectric constant and conductivity by means of a probe inserted into the medium. The air-spaced characteristic impedance of the probe is required in order to estimate the conductivity from the final value of the TDR waveform. Unbalanced probes derived from a coaxial line by replacing the outer

James A. R. Ball

2002-01-01

337

Relationship Between Faculty Characteristics and Research Productivity.  

ERIC Educational Resources Information Center

Research to identify the characteristics of the active research producer within dental schools is described. A survey was mailed to 4,901 full-time faculty members in 53 U.S. dental schools. Faculty research productivity was defined as the number of publications generated by a faculty member during an academic career. (Author/MLW)

Harrington, Marilyn S.; Levine, Daniel U.

1986-01-01

338

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 ...

Miss Lerdahl

2010-01-26

339

Photodetector and Receiver Characteristics  

NSDL National Science Digital Library

In this video from the ICT Center, learn about fiber optic receivers. Investigate the components of an optical receiver; how a photodetector converts an optical signal to an electrical one; and the characteristics of PIN, avalanche, and metal-semiconductor-metal photodiodes.The video runs 2:07 and is accompanied by a background essay, standards alignment, and discussion questions. Users who sign up for a free account can save the resource and download the video as well.

340

Characteristics of healthcare wastes  

SciTech Connect

A comprehensive understanding of the quantities and characteristics of the material that needs to be managed is one of the most basic steps in the development of a plan for solid waste management. In this case, the material under consideration is the solid waste generated in healthcare facilities, also known as healthcare waste. Unfortunately, limited reliable information is available in the open literature on the quantities and characteristics of the various types of wastes that are generated in healthcare facilities. Thus, sound management of these wastes, particularly in developing countries, often is problematic. This article provides information on the quantities and properties of healthcare wastes in various types of facilities located in developing countries, as well as in some industrialized countries. Most of the information has been obtained from the open literature, although some information has been collected by the authors and from reports available to the authors. Only data collected within approximately the last 15 years and using prescribed methodologies are presented. The range of hospital waste generation (both infectious and mixed solid waste fractions) varies from 0.016 to 3.23 kg/bed-day. The relatively wide variation is due to the fact that some of the facilities surveyed in Ulaanbaatar include out-patient services and district health clinics; these facilities essentially provide very basic services and thus the quantities of waste generated are relatively small. On the other hand, the reported amount of infectious (clinical, yellow bag) waste varied from 0.01 to 0.65 kg/bed-day. The characteristics of the components of healthcare wastes, such as the bulk density and the calorific value, have substantial variability. This literature review and the associated attempt at a comparative analysis point to the need for worldwide consensus on the terms and characteristics that describe wastes from healthcare facilities. Such a consensus would greatly facilitate comparative analyses among different facilities, studies and countries.

Diaz, L.F. [CalRecovery, Inc., Concord, California (United States)], E-mail: ludiaz@calrecovery.com; Eggerth, L.L. [CalRecovery, Inc., Concord, California (United States); Enkhtsetseg, Sh. [Ministry of Health, Ulaanbaatar (Mongolia); Savage, G.M. [CalRecovery, Inc., Concord, California (United States)

2008-07-01

341

Black time … white time: My time … your time  

Microsoft Academic Search

Indigenous time began with the Era of Creation. White time began with the invention of the calendar, sundial and clock. White time was, and still is, influenced by the calendar, clock or watch. Time to go to sleep, time to get up, time to go to work...go home, time for dinner and time to watch the football or cricket. Even

Yalmambirra

2000-01-01

342

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 ...

Mrs. Fiefia

2010-03-23

343

The First Time  

ERIC Educational Resources Information Center

In this article, the author narrates her experience of meeting a Montessori kid for the first time and shares the characteristics she observed in Montessori students. The author was working as director of academic resources in university housing at the University of Wisconsin-Madison and met Jason, a pre-med sophomore who was the resident…

Black, Beth

2011-01-01

344

animals --produce characteristic, heritable incubation times and patterns of brain  

E-print Network

into hamsters, the animals died rapidly. So the infectious agent had silently replicated for several years to hamsters, it is hard to understand why -- in thisinstance--theyretainedtheirinfectivity. It would seem

Hays, Graeme

345

Long Characteristic Method in Space and Time for Transport Problems  

E-print Network

originating : at 1 , 0 rays originating 1 on left or right : , boundaries k k k initial k k k k k k x x t x x t t allv w m m w m m mw m m - - - #2; = + D + >#3; #4; #5; #6;#7; #4; = - D + <#8; #3; #2; +#4; #4; = + D#5; #6; #4; #4;#8;#7; (2.5) Figure 2... statement of conservation for the STLC method for the cell. # of tracks 2 , , , 1 1 1 02 2 M out in SSk s k k m m k m k t k m k k k m k s ss Q v w sm s f = = D D D#2; #3;+ Y - Y + D Y - - =#6; #5; #8; #7; (2.11) Looking at the limit of fine track...

Pandya, Tara M.

2010-07-14

346

The time characteristics of cyclic service in Profibus  

Microsoft Academic Search

In Profibus master stations poll data from slave stations using the cyclic service CSRD (Cyclic Send and Request Data with Reply). Because the polling-interval determines the data sampling interval, it is important for the Profibus user to be able to know the maximum polling-interval of a cyclic service. We develop a formula for determining the maximum polling-interval of a cyclic

M. Li; L. Stoeckli

1996-01-01

347

Hangman: Characteristics Of Matter  

NSDL National Science Digital Library

The Quintessential Instructional Archive (QUIA) Web site (last mentioned in the July 13, 2001 Scout Report) contains fun, online science-related activities. The Characteristics Of Matter hangman game was created by students to test your knowledge of matter in the universe. Users can choose individual letters to see if they're right; if not, another body part appears on the hangman illustration. Puzzles include hints such as "Changes from a liquid to a gas" and "A change in which a new substance is formed." This activity gives students a fun way to use the Internet to learn about science and spark interest on a particular subject.

348

LED and Transmitter Characteristics  

NSDL National Science Digital Library

In this video from the ICT Center, learn about fiber optic transmitters. Explore the components of a fiber optic transmitter, including a source, a modulator, an electrical driving circuit, and fiber coupling mechanics. Animations illustrate how the process of spontaneous emission converts electrical information to an optical signal in a light-emitting diode, or LED. In addition, learn about characteristics that make a source suitable for fiber optic communications.The video runs 3:12 and is accompanied by a background essay, standards alignment, and discussion questions. Users who sign up for a free account can save the resource and download the video as well.

349

Wave Types and Characteristics  

NSDL National Science Digital Library

This is the first in a series of new marine meteorology modules based on COMET’s old laser disk and CD-ROM modules on marine meteorology. This module is an introduction to waves and their associated characteristics. Several types of waves are presented, from the common wind wave to the rare tsunami wave. The basic physical, mathematical, and statistical traits of waves are discussed, along with how they change once waves become swell. This material serves as a building block to subsequent modules on wave generation, propagation, and dispersion.

2014-09-14

350

Fibre Optic Sensors for Selected Wastewater Characteristics  

PubMed Central

Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising. PMID:23881131

Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

2013-01-01

351

Gender, work roles and psychosocial work characteristics as determinants of health  

Microsoft Academic Search

This paper aims to identify gender similarities and differences in psychosocial work characteristics for those in and out of paid employment, to inform research on possible health-related effects. Specifically five questions are addressed: do women report poorer work characteristics than men; are gender differences related to specific characteristics; do work characteristics differ between full- and part-time women workers and between

Sharon Matthews; Clyde Hertzman; Aleck Ostry; Chris Power

1998-01-01

352

Video Game Structural Characteristics: A New Psychological Taxonomy  

Microsoft Academic Search

Excessive video game playing behaviour may be influenced by a variety of factors including the structural characteristics\\u000a of video games. Structural characteristics refer to those features inherent within the video game itself that may facilitate\\u000a initiation, development and maintenance of video game playing over time. Numerous structural characteristics that influence\\u000a gambling frequency and expenditure have been identified in the gambling

Daniel King; Paul Delfabbro; Mark Griffiths

2010-01-01

353

Characteristics of Business Owners Survey  

NSDL National Science Digital Library

The Census Bureau has released the results of the 1992 Characteristics of Business Owners Survey (CBO). These results provide data for comparing the "selected economic, demographic, and sociological characteristics" of business owners.

354

Telling Time  

NSDL National Science Digital Library

Students - These games will help you practice telling time and calculating time measurements. Students practice telling time from an analog clock. Play this game to figure out What time is it? Play this game at least 15 times, then come back and play another clock game. Students practice your telling time skills by clicking here. In this game you determine What time will it be?. Play this game at least 10 times. After ...

Mr. Udy

2006-11-14

355

Three Characteristics of Effective Teachers  

ERIC Educational Resources Information Center

This article discusses three characteristics that are often associated with successful music educators. The three characteristics discussed include nonverbal communication, teacher self-efficacy, and servant leadership. Although there is no magical combination of characteristics that will produce an effective music teacher, these three attributes…

Steele, Natalie A.

2010-01-01

356

Characteristics of successful employer brands  

Microsoft Academic Search

Abstract Inthe last decade, employer branding has been hailed as a key strategic marketing activity. This study examines ,the perceived characteristics of successful ,and unsuccessful employer brands. Information from an expert ,panel is analysed ,to uncover ,successful\\/unsuccessful employer,brand characteristics and to establish areas of convergence ,and divergence with existing product and corporate branding ,literature. A typology ,of the ,characteristics is

Lara Moroko; Mark D Uncles

2008-01-01

357

8-, 16-, and 32-Bit Processors: Characteristics and Appropriate Applications.  

ERIC Educational Resources Information Center

Defines and describes the components and functions that constitute a microcomputer--bits, bytes, address register, cycle time, data path, and bus. Characteristics of 8-, 16-, and 32-bit machines are explained in detail, and microprocessor evolution, architecture, and implementation are discussed. Application characteristics or types for each bit…

Williams, James G.

1984-01-01

358

Regional relationships between basin size and runoff characteristics  

Microsoft Academic Search

The effect of basin size on runoff characteristics is investigated. The maximum observed floodflow, the maximum annual constant loss, the lag time and the unitgraph peak for a certain storm duration of basins in the western and northwestern regions of Greece are increasing power functions of the basin size. These functions explain significantly the variation in the runoff characteristics. For

MARIA MIMIKOU

1984-01-01

359

Video Game Structural Characteristics: A New Psychological Taxonomy  

ERIC Educational Resources Information Center

Excessive video game playing behaviour may be influenced by a variety of factors including the structural characteristics of video games. Structural characteristics refer to those features inherent within the video game itself that may facilitate initiation, development and maintenance of video game playing over time. Numerous structural…

King, Daniel; Delfabbro, Paul; Griffiths, Mark

2010-01-01

360

Firm characteristics, total quality management, and financial performance  

Microsoft Academic Search

This paper uses a sample of quality award winners to empirically test hypotheses that relate changes in operating income associated with effective implementation of total quality management (TQM) to various firm characteristics. The characteristics examined are firm size, the degree of capital intensity, the degree of diversification, the timing of TQM implementation, and the maturity of the program. We find

Kevin B Hendricks; Vinod R Singhal

2001-01-01

361

Firm characteristics, total quality management, and financial performance  

Microsoft Academic Search

This paper uses a sample of quality award winners to empirically test hypotheses that relate changes in operating income associated with effective implementation of total quality management (TQM) to various firm characteristics. The characteristics examined are firm size, the degree of capital intensity, the degree of diversification, the timing of TQM implementation, and the maturity of the program. We find

Kevin B. Hendricks; Vinod R. Singhal

2000-01-01

362

An Implicit Characteristic Based Method for Electromagnetics  

NASA Technical Reports Server (NTRS)

An implicit characteristic-based approach for numerical solution of Maxwell's time-dependent curl equations in flux conservative form is introduced. This method combines a characteristic based finite difference spatial approximation with an implicit lower-upper approximate factorization (LU/AF) time integration scheme. This approach is advantageous for three-dimensional applications because the characteristic differencing enables a two-factor approximate factorization that retains its unconditional stability in three space dimensions, and it does not require solution of tridiagonal systems. Results are given both for a Fourier analysis of stability, damping and dispersion properties, and for one-dimensional model problems involving propagation and scattering for free space and dielectric materials using both uniform and nonuniform grids. The explicit Finite Difference Time Domain Method (FDTD) algorithm is used as a convenient reference algorithm for comparison. The one-dimensional results indicate that for low frequency problems on a highly resolved uniform or nonuniform grid, this LU/AF algorithm can produce accurate solutions at Courant numbers significantly greater than one, with a corresponding improvement in efficiency for simulating a given period of time. This approach appears promising for development of dispersion optimized LU/AF schemes for three dimensional applications.

Beggs, John H.; Briley, W. Roger

2001-01-01

363

Wafer characteristics via reflectometry  

DOEpatents

Various exemplary methods (800, 900, 1000, 1100) are directed to determining wafer thickness and/or wafer surface characteristics. An exemplary method (900) includes measuring reflectance of a wafer and comparing the measured reflectance to a calculated reflectance or a reflectance stored in a database. Another exemplary method (800) includes positioning a wafer on a reflecting support to extend a reflectance range. An exemplary device (200) has an input (210), analysis modules (222-228) and optionally a database (230). Various exemplary reflectometer chambers (1300, 1400) include radiation sources positioned at a first altitudinal angle (1308, 1408) and at a second altitudinal angle (1312, 1412). An exemplary method includes selecting radiation sources positioned at various altitudinal angles. An exemplary element (1650, 1850) includes a first aperture (1654, 1854) and a second aperture (1658, 1858) that can transmit reflected radiation to a fiber and an imager, respectfully.

Sopori, Bhushan L. (Denver, CO)

2010-10-19

364

Chapter 3 Numerical Characteristics and Characteristic Functions c # 3.3 Characteristic functions  

E-print Network

.3 Characteristic functions 3.3.1 Definitions Modulus inequality: |E| E||. yyy. P = + i. K|E| = (E)2 + (E)2, E.3 Characteristic functions 3.3.1 Definitions Modulus inequality: |E| E||. yyy. P = + i. K|E| = (E)2 + (E)2, E and Characteristic Functions c �á# 3.3 Characteristic functions 3.3.1 Definitions Modulus inequality: |E| E||. yyy

Zhang, Li-Xin

365

TIME MANAGEMENT Time Management Questionnaire  

E-print Network

= ____ Number of hours for meals/snacks (including preparation/clean-up time) ____ x 7 = ____ Travel time of hours for meals/snacks (including preparation/clean-up time) 3 x 7 = 21 Travel time to and from campus 1

366

Clinical Characteristics of Primary Peritoneal Carcinoma  

PubMed Central

Purpose The goal of this study was to determine the clinical and therapeutic characteristics of women with a primary peritoneal carcinoma (PPC). Materials and Methods A retrospective clinical study was conducted to evaluate 22 women diagnosed with a PPC from 1993 to 2007 at the Hospitals of The Catholic University of Korea. Diagnoses were based on the Gynecologic Oncology Group criteria and clinical data. We collected patient clinicopathological data including age, presenting symptoms, pretreatment CA-125 values (U/ml), clinical stage (based on the FIGO stage), performance status (using the Eastern Cooperative Oncology Group scale), whether cytoreductive surgery was optimal or not, types of chemotherapy and response to treatment. We evaluated the clinical characteristics and response to treatment, time to treatment failure and overall survival. Results The median overall survival of all patients was 23.1 months. The estimated 3-year survival rate was 29% (SE, 13%). The response rate to first-line platinum-based chemotherapy was 79% and the median time to treatment failure was 9.9 months (95% confidence interval, 1.38~18.4 months). By univariate and multivariate analysis, performance status was the only significant factor associated with overall survival (p<0.05). Conclusion We evaluated the clinical characteristics and treatment response of patients with a primary peritoneal carcinoma. Our results showed that it is possible to achieve long-term survival in patients with PPC. A further clinical study is to need to establish clinical characteristics and treatment outcomes. PMID:19746214

Roh, Sang Young; Hong, Sook Hee; Ko, Yoon Ho; Kim, Tae Hee; Lee, Myung Ah; Shim, Byoung Yong; Woo, In Sook; Kang, Jin Hyoung; Hong, Young Seon; Lee, Kyung Shik

2007-01-01

367

Characteristic Features of the Volcanism of the Siberian Platform  

Microsoft Academic Search

WIDESPREAD VOLCANISM is characteristic of the Siberian platform, and was especially intense during uppermost Paleozoic and lower Mesozoic time. The Siberian traps, which occupy an area of more than 1,500,000 km\\

V. S. SOBOLEV

368

Elapsed Time  

NSDL National Science Digital Library

In this activity, students are shown three clocks, one with a starting time, one an ending time, and the third has the current time. At first the current time is the same as the start time and the students advance the current time by either one hour, five minutes, or one minute until they get to the end time. The applet keeps track of how much total time has elapsed. The student can also switch to guess mode where they are given a start time and end time and have to guess the amount of elapsed time between them. This activity allows students to practice reading clocks and finding how much time has elapsed between two times. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

2010-01-01

369

Characterization of Neonatal Personnel Time Inputs and Prediction From Clinical Variables — A Time and Motion Study  

Microsoft Academic Search

OBJECTIVE: To characterize and predict personnel time inputs to neonatal intensive care using infant characteristics from chart review.STUDY DESIGN: For 12 hours each day, observers timed all direct care, charting, discussions, and procedures for 154 infants. Time inputs were correlated with 40 infant characteristics and resource markers, as well as the Score for Neonatal Acute Physiology (SNAP) for that day

John A F Zupancic; Douglas K Richardson

2002-01-01

370

Characteristics of Engineering Citations.  

ERIC Educational Resources Information Center

An analysis of 4,780 citations taken from scholarly journals in 16 areas of engineering showed that journals are cited 53% of the time; electrical engineering literature has the shortest "half-life"; and literature types age at different rates for engineering researchers, with books having the longest useful lives and conference papers the…

Musser, Linda R.; Conkling, Thomas W.

1996-01-01

371

Characteristics of flight simulator visual systems  

NASA Technical Reports Server (NTRS)

The physical parameters of the flight simulator visual system that characterize the system and determine its fidelity are identified and defined. The characteristics of visual simulation systems are discussed in terms of the basic categories of spatial, energy, and temporal properties corresponding to the three fundamental quantities of length, mass, and time. Each of these parameters are further addressed in relation to its effect, its appropriate units or descriptors, methods of measurement, and its use or importance to image quality.

Statler, I. C. (editor)

1981-01-01

372

Noise characteristics in IFOG  

NASA Astrophysics Data System (ADS)

IFOG (Interferometric Fiber Optic Gyroscope) is the most promising angular velocity sensor in the inertial guidance market due to its attractive advantages, which is often regarded as the next generation gyro that can ultimately replace the traditional mechanical gyroscope. In order to improve the performance of IFOG, especially to low down the bias drift and angle random walk (ARW) of IFOG, it is valuable to research the noise characteristics of IFOG. In this paper, the ultra low frequency random noise and the relatively high frequency random noise has been investigated respectively. The experimental data of a practical open loop IFOG is obtained by different sampling frequency, through which the different frequency scope of the noise can be researched separately. The frequency spectral analysis of the noise deduces the follow result: (1) the relative high frequency (higher than about 0.001 Hz) random noise can be approximately modeled as Gaussian white noise (GWN), and its spectral range is determined by the system bandwidth of IFOG. The angle random walk of IFOG is determined by this kind of noise. (2) The ultra low frequency (lower than about 0.001 Hz) random noise can not be Gaussian white noise, which is much more great than other noises, and with the rise of frequency, the power of the relevant frequency component is lower down sharply. The ultra low frequency noise is often regarded as the source of bias drift of IFOG.

Chang, Jianxin; Wang, Peng; Qin, BingKun; Chen, Shufen

2000-10-01

373

Sensor Characteristics Reference Guide  

SciTech Connect

The Buildings Technologies Office (BTO), within the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), is initiating a new program in Sensor and Controls. The vision of this program is: • Buildings operating automatically and continuously at peak energy efficiency over their lifetimes and interoperating effectively with the electric power grid. • Buildings that are self-configuring, self-commissioning, self-learning, self-diagnosing, self-healing, and self-transacting to enable continuous peak performance. • Lower overall building operating costs and higher asset valuation. The overarching goal is to capture 30% energy savings by enhanced management of energy consuming assets and systems through development of cost-effective sensors and controls. One step in achieving this vision is the publication of this Sensor Characteristics Reference Guide. The purpose of the guide is to inform building owners and operators of the current status, capabilities, and limitations of sensor technologies. It is hoped that this guide will aid in the design and procurement process and result in successful implementation of building sensor and control systems. DOE will also use this guide to identify research priorities, develop future specifications for potential market adoption, and provide market clarity through unbiased information

Cree, Johnathan V.; Dansu, A.; Fuhr, P.; Lanzisera, Steven M.; McIntyre, T.; Muehleisen, Ralph T.; Starke, M.; Banerjee, Pranab; Kuruganti, T.; Castello, C.

2013-04-01

374

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.

375

Time Out for Time Management.  

ERIC Educational Resources Information Center

Discusses time management skills, noting that effective time management entails awareness of such things as how we use time and when our mental energy peaks and falls. Offers time management suggestions for day-care administrators such as developing a realistic "to-do" list, scheduling uninterrupted time to engage in important tasks, and limiting…

Herr, Judy; And Others

1995-01-01

376

Pharmacological characteristics of metamizole.  

PubMed

Metamizole (dipyrone) is a popular analgetic, non-opioid drug, commonly used in human and veterinary medicine. In some cases, this agent is still incorrectly classified as a non-steroidal anti-inflammatory drug (NSAID). Metamizole is a pro-drug, which spontaneously breaks down after oral administration to structurally related pyrazolone compounds. Apart from its analgesic effect, the medication is an antipyretic and spasmolytic agent. The mechanism responsible for the analgesic effect is a complex one, and most probably rests on the inhibition of a central cyclooxygenase-3 and activation of the opioidergic system and cannabinoid system. Metamizole can block both PG-dependent and PG-independent pathways of fever induced by LPS, which suggests that this drug has a profile of antipyretic action distinctly different from that of NSAIDs. The mechanism responsible for the spasmolytic effect of metamizole is associated with the inhibited release of intracellular Ca2+ as a result of the reduced synthesis of inositol phosphate. Metamizole is predominantly applied in the therapy of pain of different etiology, of spastic conditions, especially affecting the digestive tract, and of fever refractory to other treatments. Co-administration of morphine and metamizole produces superadditive, antinociceptive effects. Metamizole is a relatively safe pharmaceutical preparation although it is not completely free from undesirable effects. Among these side-effects, the most serious one that raises most controversy is the myelotoxic effect. It seems that in the past the risk of metamizole-induced agranulocytosis was exaggerated. Despite the evidence showing no risk of teratogenic and embryotoxic effects, the drug must not be administered to pregnant women, although it is allowed to be given to pregnant and lactating animals. This paper seeks to describe the characteristics of metamizole in the light of current knowledge. PMID:24724493

Jasiecka, A; Ma?lanka, T; Jaroszewski, J J

2014-01-01

377

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

378

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

379

Gases: Characteristics and Properties  

NSDL National Science Digital Library

The first site related to ideal gas, called Ideal and Real Gas Laws, is maintained by Liina Ladon of Townsen University (1). Visitors can read about the properties of ideal gases, what the ideal gas law is, how to use it, and much more. The next site, titled Gas Laws, (2) is offered by the Ohio State University Department of Chemistry. This interactive site contains Shockwave movies of animations and audio files that describe what a gas is, the Ideal Gas Law equation, mixtures of gases, and problems using the ideal gas law. The University of Oregon site, Virtual Laboratory, teaches about the ideal gas law on the Welcome to the Pressure Chamber page (3). Those who enjoy online interaction will enjoy being able to control the action of a piston in a pressure chamber to see how the gases inside react. The fourth site includes another fun multimedia activity related to ideal gases provided by the Department of Physics and Astronomy at Western Washington University. The Air Filled Balloon in Liquid Nitrogen (4) movie shows an actual experiment of the effects on a balloon that's covered with liquid nitrogen. The page contains some additional information on the science behind the observations. The next site, called Ideal Gas Equations (5) is an online calculator that's part of Kean University's Department of Geology and Meteorology Web site. Users can calculate the pressure, volume, or temperature of a gas by inputting known variables into the various forms. Several methods and variations of calculating the values are provided as well as brief instructions. The next page from North Carolina State University's Basic Concepts in Environmental Science Web site is called Characteristics of Gases (6). Part of a larger learning module, the lesson plans objective is to use the ideal gas law to determine gas volumes at different absolute temperatures and absolute pressures. Everything needed to conduct the activity is provided including links to a volume calculator and practice problems. The seventh site is another animation that illustrates how gases react, called Molecular Model for an Ideal Gas (7). By changing the number of molecules in the chamber, their velocity, and the pressure and width of the container, users get to see how the molecules react to the conditions. The last site, Gases and Their Properties, is maintained by the Electronic Teaching Assistance Program(8). Students learn about the history of gas science, how gas laws describe ideal gases, what Dalton's Law and Graham's Law are, and much more.

Brieske, Joel A.

380

Time Series Analysis Nonstationary Data Analysis by Time Deformation  

Microsoft Academic Search

In this article we discuss methodology for analyzing nonstationary time series whose periodic nature changes approximately linearly with time. We make use of the M-stationary process to describe such data sets, and in particular we use the discrete Euler(p) model to obtain forecasts and estimate the spectral characteristics. We discuss the use of the M-spectrum for displaying linear time-varying periodic

HENRY L. GRAY; CHU-PING C. VIJVERBERG; WAYNE A. WOODWARD

381

Multiple steady states for characteristic initial value problems  

NASA Technical Reports Server (NTRS)

The time dependent, isentropic, quasi-one-dimensional equations of gas dynamics and other model equations are considered under the constraint of characteristic boundary conditions. Analysis of the time evolution shows how different initial data may lead to different steady states and how seemingly anamolous behavior of the solution may be resolved. Numerical experimentation using time consistent explicit algorithms verifies the conclusions of the analysis. The use of implicit schemes with very large time steps leads to erroneous results.

Salas, M. D.; Abarbanel, S.; Gottlieb, D.

1984-01-01

382

Characteristics of Ethical Business Cultures  

ERIC Educational Resources Information Center

The purpose of this study was to identify general characteristics attributed to ethical business cultures by executives from a variety of industries. Our research identified five clusters of characteristics: (1) Mission- and Values-Driven; (2) Stakeholder Balance; (3) Leadership Effectiveness; (4) Process Integrity; and (5) Long-term Perspective.…

Ardichvili, Alexandre A.; Jondle, Douglas J.; Mitchell, James A.

2008-01-01

383

A Taxonomy of Usability Characteristics  

E-print Network

A Taxonomy of Usability Characteristics in Virtual Environments Deliverable to Office of Naval This document can be found at http://csgrad.cs.vt.edu/jgabbard/ve/taxonomy/ #12;#12;A Taxonomy of Usability accomplished, yielding a comprehensive multi-dimensional taxonomy of usability characteristics specifically

Gabbard, Joseph L.

384

CHARACTERISTICS OF FISH POPULATIONS IN  

E-print Network

CHARACTERISTICS OF FISH POPULATIONS IN UPPER MISSISSIPPI RIVER BACKWATER AREAS Manne Bio and Wildlife, John S. Gottschalk, Direct or CHARACTERISTICS OF FISH POPULATIONS IN UPPER MISSISSIPPI RIVER B 16 Ifercentage composition 16 Weight per acre 16 Comparison with other waters 20 Mississippi River

385

Cattaraugus Creek Characteristics  

NSDL National Science Digital Library

Students start this exercise using topographic maps of an area recently visited on a field trip to calculate and consider stream gradient of a major river south of Buffalo, NY. The activity then changes gears to have students work with discharge measurements from this stream. They use these measurements to plot and evaluate a few hydrographs which are used to compare how discharge in this stream can be used to consider how much precipitation was received in a certain year. In this lab, students practice mathematically calculating geomorphic properties of a stream, plotting data, and comparing topographic maps to what they observed on the recent field trip. Designed for a geomorphology course Uses online and/or real-time data Addresses student fear of quantitative aspect and/or inadequate quantitative skills

Kevin Williams

386

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.

2012-08-03

387

Characteristics of synchrotron radiation  

SciTech Connect

Synchrotron radiation is having a very significant impact on the many disciplines that make use of the radiation in the x-ray, vacuum ultraviolet, and infra-red regions of the spectrum. The rapidly increasing demand for beam time at existing facilities, the construction and commissioning of new facilities, and the world wide planning for future sources is clear testimony to the unique, interdisciplinary nature of the research applications. The nature of synchrotron radiation research continues to change and expand. This conference on the application of synchrotron radiation (SR) to polymer research illustrates that point. In this introductory paper it is impossible to cover in depth any of the applications. The intent, instead, is to give a brief, condensed summary of the properties of SR which have brought it to the fore as a research tool. No single source can provide the proper radiation for all applications. This paper should provide enough information and references to allow anyone contemplating a particular experiment to understand the widely varying parameters from different facilities, and thereby make some initial decisions concerning feasibility, and proper source. The NSLS will, in general, be used for illustration purposes since the conference is being held at Brookhaven where the attendees can get first hand familiarity with the facility.

Thomlinson, W.

1984-01-01

388

Characteristics of gamma-ray line flares  

NASA Technical Reports Server (NTRS)

Observations of solar gamma rays by the Solar Maximum Mission (SMM) demonstrate that energetic protons and ions are rapidly accelerated during the impulsive phase. To understand the acceleration mechanisms for these particles, the characteristics of the gamma ray line flares observed by SMM were studied. Some very intense hard X-ray flares without detectable gamma ray lines were also investigated. Gamma ray line flares are distinguished from other flares by: (1) intense hard X-ray and microwave emissions; (2) delay of high energy hard X-rays; (3) emission of type 2 and/or type 4 radio bursts; and (4) flat hard X-ray spectra (average power law index: 3.1). The majority of the gamma ray line flares shared all these characteristics, and the remainder shared at least three of them. Positive correlations were found between durations of spike bursts and spatial sizes of flare loops as well as between delay times and durations of spike bursts.

Bai, T.; Dennis, B.

1983-01-01

389

Analytic prediction of airplane equilibrium spin characteristics  

NASA Technical Reports Server (NTRS)

The nonlinear equations of motion are solved algebraically for conditions for which an airplane is in an equilibrium spin. Constrained minimization techniques are employed in obtaining the solution. Linear characteristics of the airplane about the equilibrium points are also presented and their significance in identifying the stability characteristics of the equilibrium points is discussed. Computer time requirements are small making the method appear potentially applicable in airplane design. Results are obtained for several configurations and are compared with other analytic-numerical methods employed in spin prediction. Correlation with experimental results is discussed for one configuration for which a rather extensive data base was available. A need is indicated for higher Reynolds number data taken under conditions which more accurately simulate a spin.

Adams, W. M., Jr.

1972-01-01

390

Measuring spatial variability in soil characteristics  

DOEpatents

The present invention provides systems and methods for measuring a load force associated with pulling a farm implement through soil that is used to generate a spatially variable map that represents the spatial variability of the physical characteristics of the soil. An instrumented hitch pin configured to measure a load force is provided that measures the load force generated by a farm implement when the farm implement is connected with a tractor and pulled through or across soil. Each time a load force is measured, a global positioning system identifies the location of the measurement. This data is stored and analyzed to generate a spatially variable map of the soil. This map is representative of the physical characteristics of the soil, which are inferred from the magnitude of the load force.

Hoskinson, Reed L. (Rigby, ID); Svoboda, John M. (Idaho Falls, ID); Sawyer, J. Wayne (Hampton, VA); Hess, John R. (Ashton, ID); Hess, J. Richard (Idaho Falls, ID)

2002-01-01

391

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

392

Making Time  

ERIC Educational Resources Information Center

This article presents several tips that teachers can use to teach children about time. One activity, investigating 24-hour time, aims to familiarise upper primary students with converting a.m. and p.m. notations to 24-hour time. Another activity requires students to construct a calendar month in order to familiarize themselves with the components…

Gorham, Gail; Bobis, Janette

2005-01-01

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

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.

2012-06-26

395

Modelling Time  

E-print Network

We briefly review two concepts of time - the usual time associated with "being" and more recent ideas, answering to the description of "becoming". The approximation involved in the former is examined. Finally we argue that it is (unpredictable) fluctuations that underlie time.

Burra G. Sidharth

2008-09-03

396

Space-time ODN suppressing reverberation method  

Microsoft Academic Search

Reverberation of active sonar that resemble clutter of airborne radar has space-time coupling characteristic. Based on which, a method of space-time ODN reverberation is presented in this paper. Project matrix method is utilized to design time and space ODN filters. The time ODN filter is used to suppress the mainlobe reverberation with the same direction as the target. The space

Zhan Haoke; Cai Zhiming; Yuan Bingcheng

2008-01-01

397

Practicing school psychologists: Their characteristics, activities, and populations served  

Microsoft Academic Search

Administered the National School Psychology Questionnaire, which was developed for the present study, to a nationwide, random sample of 877 school psychologists. The measure was designed to assess demographic characteristics, actual and desired activities, and actual and desired amount of time spent with various student groups. Results indicate that the majority of time was spent in assessment (54%), followed by

Douglas K. Smith

1984-01-01

398

G-seat system step input and sinusoidal response characteristics  

NASA Technical Reports Server (NTRS)

The step input and sinusoidal response characteristics of a pneumatically driven computer controlled G set are examined in this study. The response data show that this system can be modeled as a first order system with an 0.08 sec time lag and a 0.53 sec time constant.

Showalter, T. W.; Miller, R. J.

1978-01-01

399

Investigation of dynamic characteristics of a turbine-propeller engine  

NASA Technical Reports Server (NTRS)

Time constants that characterize engine speed response of a turbine-propeller engine over the cruising speed range for various values of constant fuel flow and constant blade angle were obtained both from steady-state characteristics and from transient operation. Magnitude of speed response to changes in fuel flow and blade angle was investigated and is presented in the form of gain factors. Results indicate that at any given value of speed in the engine cruising speed range, time constants obtained both from steady-state characteristics and from transient operation agree satisfactorily for any given constant fuel flow, whereas time constants obtained from transient operation exceed time constants obtained from steady-state characteristics by approximately 14 percent for any given blade angle.

Oppenheimer, Frank L; Jacques, James R

1951-01-01

400

Assessment of wind characteristics and wind turbine characteristics in Taiwan  

Microsoft Academic Search

Wind characteristics and wind turbine characteristics in Taiwan have been thoughtfully analyzed based on a long-term measured data source (1961–1999) of hourly mean wind speed at 25 meteorological stations across Taiwan. A two-stage procedure for estimating wind resource is proposed. The yearly wind speed distribution and wind power density for the entire Taiwan is firstly evaluated to provide annually spatial

Tsang-Jung Chang; Yu-Ting Wu; Hua-Yi Hsu; Chia-Ren Chu; Chun-Min Liao

2003-01-01

401

Quantum Time  

E-print Network

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 well as in space. We use Morlet wavelet decomposition to ensure convergence and normalization of the path integrals. We derive the Schr\\"odinger equation in four dimensions from the short time limit of the path integral expression. We verify that we recover standard quantum theory in the non-relativistic, semi-classical, and long time limits. Quantum time is an experiment factory: most foundational experiments in quantum mechanics can be modified in a way that makes them tests of quantum time. We look at single and double slits in time, scattering by time-varying electric and magnetic fields, and the Aharonov-Bohm effect in time.

John Ashmead

2010-05-05

402

The Physical Characteristics of Minerals  

NSDL National Science Digital Library

Offered by Amethyst Galleries, Inc. (an online minerals store), the Physical Characteristics of Minerals Web site offers a detailed description of how minerals are identified. Each page gives good information and examples of a particular characteristic (e.g, color, hardness, cleavage, feel, and taste). Also, on the first page are links to dozens of minerals that are categorized by name, class, interesting groupings, and great localities. These give the class, subclass, group, uses, physical characteristics, and sample photographs of that particular mineral. Anyone interested in geology, minerals, or gemstones will find this site very informative and fun to explore.

403

Simulation and Experimental Investigation of Structural Dynamic Frequency Characteristics Control  

PubMed Central

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results. PMID:22666072

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

404

Real time automated inspection  

DOEpatents

A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

Fant, Karl M. (Minneapolis, MN); Fundakowski, Richard A. (Saint Paul, MN); Levitt, Tod S. (Minneapolis, MN); Overland, John E. (Plymouth, MN); Suresh, Bindinganavle R. (New Brighton, MN); Ulrich, Franz W. (Minneapolis, MN)

1985-01-01

405

Real time automated inspection  

DOEpatents

A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

1985-05-21

406

Health-Compromising Behaviors characteristics  

E-print Network

of vulnerability #12;Substance abuse: Links " Conflict with parents and family problems " Impulsivity " StressHealth-Compromising Behaviors characteristics substance abuse and dependence ­ opponent process theory ­ incentive salience ­ frontal executive effects alcohol abuse and dependence smoking #12

Meagher, Mary

407

Health-Compromising Behaviors characteristics  

E-print Network

Health-Compromising Behaviors characteristics substance abuse and dependence ­ opponent process Behaviors develop gradually rather than being acquired "all at once" Substance abuse of all kinds;Substance abuse: Links Conflict with parents and family problems Impulsivity Stress Seems

Meagher, Mary

408

Concrete Pavements Surface Characteristics Program  

E-print Network

.E. Structural Faulting, fatigue cracking Material ASR, D-cracking Functional (Surface Characteristics) Friction friction as a function of speed ­ ASTM E 1911 Measures wet friction on small rubber pads which slow from 50

409

Characteristics of Populations (title provided or enhanced by cataloger)  

NSDL National Science Digital Library

The concept that populations are dynamic with identifiable characteristics and measurable growth patterns is addressed in this lesson plan. Population characteristics are explained, including biotic potential, density, natality, mortality, and age distribution. The lesson plan provides objectives, skills, time needed, a content outline, materials, significant terms, and questions for the class. The main goal of the lesson plan is for students to develop an understanding of the interdependence of all organisms and the need for conserving natural resources.

410

IRRADIATION EFFECTS ON THE PHYSICAL CHARACTERISTICS OF SEWAGE SLUDGE  

SciTech Connect

The radiation effects on the physical characteristic of the sewage sludge were studied in order to obtain information which will be used for study on the enhancement of the sludge's dewaterability. Water contents, capillary suction time, zeta potential, irradiation dose, sludge acidity, total solid concentration, sludge particle size and microbiology before and after irradiation were investigated. Irradiation gave an effect on physical characteristics sludge. Water content in sludge cake could be reduced by irradiation at the dose of 10kGy.

Lee, M-J.; Lee, J-K.; Yoo, D-H.; Ho, K.

2004-10-05

411

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.

Larry Flammer

412

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.

William L. Newman

1997-01-01

413

Heat transfer characteristics of an emergent strand  

NASA Technical Reports Server (NTRS)

A mathematical model was developed to describe the heat transfer characteristics of a hot strand emerging into a surrounding coolant. A stable strand of constant efflux velocity is analyzed, with a constant (average) heat transfer coefficient on the sides and leading surface of the strand. After developing a suitable governing equation to provide an adequate description of the physical system, the dimensionless governing equation is solved with Laplace transform methods. The solution yields the temperature within the strand as a function of axial distance and time. Generalized results for a wide range of parameters are presented, and the relationship of the results and experimental observations is discussed.

Simon, W. E.; Witte, L. C.; Hedgcoxe, P. G.

1974-01-01

414

Coal-water slurry atomization characteristics  

SciTech Connect

The overall objective of this work was to fully characterize the CWS fuel sprays of a medium-speed diesel engine injection system. Specifically, the spray plume penetration as a function of time was determined for a positive-displacement fuel injection system. The penetration was determined as a function of orifice diameter, coal loading, gas density in the engine, and fuel line pressure. Preliminary droplet information also was obtained. The results of this study will assist CWS engine development by providing much needed insight about the fuel spray. In addition, the results will aid the development and use of CWS engine cycle simulations which require information on the fuel spray characteristics.

Caton, J.A.; Kihm, K.D.

1994-04-01

415

Calibration of a ?- Re ? transition model and its application in low-speed flows  

NASA Astrophysics Data System (ADS)

The prediction of laminar-turbulent transition in boundary layer is very important for obtaining accurate aerodynamic characteristics with computational fluid dynamic (CFD) tools, because laminar-turbulent transition is directly related to complex flow phenomena in boundary layer and separated flow in space. Unfortunately, the transition effect isn't included in today's major CFD tools because of non-local calculations in transition modeling. In this paper, Menter's ?- Re ? transition model is calibrated and incorporated into a Reynolds-Averaged Navier-Stokes (RANS) code — Trisonic Platform (TRIP) developed in China Aerodynamic Research and Development Center (CARDC). Based on the experimental data of flat plate from the literature, the empirical correlations involved in the transition model are modified and calibrated numerically. Numerical simulation for low-speed flow of Trapezoidal Wing (Trap Wing) is performed and compared with the corresponding experimental data. It is indicated that the ?- Re ? transition model can accurately predict the location of separation-induced transition and natural transition in the flow region with moderate pressure gradient. The transition model effectively imporves the simulation accuracy of the boundary layer and aerodynamic characteristics.

Wang, YunTao; Zhang, YuLun; Meng, DeHong; Wang, GunXue; Li, Song

2014-12-01

416

[Characteristics analysis of human tongue reflectance spectra].  

PubMed

The present paper presents the spectroscopic analysis method. Eighty samples of spectra data of tongue parts with coating and without coating were collected by Usb4000 spectrometer of Ocean Optics, then comparing the spectra data of the different parts of tongue we found that there was a relation between the spectra characteristics and tongue coating, and further analysis of the spectra data showed that there was a big difference between the two parts within the wavelength range between 500 and 600 nm. It was also found that the biggest differences appear when the wavelength is 579.39 nm, and at the same time, different colors of tongue coating were also compared, and the spectrum was also quite different because of different color and thickness of the tongue coating. The experiment results show that different color, thickness, and dryness of the human tongue coating lead to different spectral characteristics, and compared with the current colorimetric method of tongue characterization, spectral reflectance can reflect more physiological and pathological information. The experiment results also indicated that the different spectral characteristics of tongue property and tongue coating will be used for further separation of these two parts, and to provide an objective analysis index for tongue coating qualitative and quantitative analysis, so as to promote the objectivity of the TCM. PMID:25474963

Zhao, Jing; Liu, Ming; Lu, Xiao-zuo; Li, Gang

2014-08-01

417

[Characteristics analysis of human tongue reflectance spectra].  

PubMed

The present paper presents the spectroscopic analysis method. Eighty samples of spectra data of tongue parts with coating and without coating were collected by Usb4000 spectrometer of Ocean Optics, then comparing the spectra data of the different parts of tongue we found that there was a relation between the spectra characteristics and tongue coating, and further analysis of the spectra data showed that there was a big difference between the two parts within the wavelength range between 500 and 600 nm. It was also found that the biggest differences appear when the wavelength is 579.39 nm, and at the same time, different colors of tongue coating were also compared, and the spectrum was also quite different because of different color and thickness of the tongue coating. The experiment results show that different color, thickness, and dryness of the human tongue coating lead to different spectral characteristics, and compared with the current colorimetric method of tongue characterization, spectral reflectance can reflect more physiological and pathological information. The experiment results also indicated that the different spectral characteristics of tongue property and tongue coating will be used for further separation of these two parts, and to provide an objective analysis index for tongue coating qualitative and quantitative analysis, so as to promote the objectivity of the TCM. PMID:25508742

Zhao, Jing; Liu, Ming; Lu, Xiao-zuo; Li, Gang

2014-08-01

418

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

419

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.

420

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

421

Elapsed Time  

NSDL National Science Digital Library

This lesson is designed to develop students' ability to find elapsed time given starting and ending times. This lesson provides links to discussions and activities related to the topic as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2011-05-24

422

Managing Time.  

ERIC Educational Resources Information Center

This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household…

Murphy, Linda; Della Corte, Suzanne

1991-01-01

423

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.

2012-06-26

424

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

425

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.

Stephen Greb

426

Electrochemical characteristics of lithium-ion cells  

SciTech Connect

The authors describe below the electrochemical performance characteristics, including charge-discharge characteristics at different rates, of cylindrical 18650 (18 mm diameter, 65 mm high) and prismatic lithium ion cells at ambient and sub-ambient temperatures. Ragone plots of power and energy data for these cells are compared and indicate that at room temperature the prismatic lithium ion cells (approx. 500 mAh) exhibit higher specific power and power density than the 18650 cells (approx. 1,100 mAhr). The cell impedance was measured between 35 C and {minus}40 C at three open circuit voltages: 4.1 v (fully charged), 3.6 v (partially discharged), and 3.1 v (almost completely discharged). Over the temperature range from 35 C to {minus}20 C, the cell impedance is nearly constant for both cell types and increases by 2 to 3 times at {minus}40 C. The impedance doesn`t vary significantly with open circuit voltage (OCV). These cells show very little voltage drop at room temperature for current pulses up to 1 A. The charge-discharge characteristics of the cells are being studied at different rates as a function of temperature to compute the power, energy, and capacity outputs. This will not only broaden the database on lithium ion cells, but will also allow us to evaluate the suitability of the cells as power sources for low temperature applications. Other electrochemical characteristics of these cells including pulse response are being evaluated. Impedance measurements of the cells under load are planned to make meaningful correlations between the voltage drop and the current pulse amplitude.

Nagasubramanian, C.; Roth, P.; Jungst, R.G.; Clark, N.

1998-01-01

427

Time ephemeris  

NASA Astrophysics Data System (ADS)

The location-independent part of barycentric coordinate time and geocentric coordinate time (TCB-TCG), the difference between the two new time scales adopted by the IAU, was integrated numerically for three JPL planetary/lunar ephemerides; DE102, DE200, and DE245. The differences among these three integrations were mostly explained by the difference in the adopted constants of the ephemerides. It was shown that the post-Newtonian correction and the perturbation by asteroids are negligible except for the mean rate, LC. The comparison of these numerical integrations with the analytical formulas of Hirayama et al. (1987) and Fairhead & Bretagnon (1990) as well as their extended versions lead to the best estimate of LC as 1.480 826 845 7 x 10-8 + or - 1.0 x 10-17. Combining this with the recent value of the geoid potential in Bursa et al. (1992), we estimate the value of LB, the scale difference between TCB and terrestrial time (TT), as 1.550 519 748 x 10-8 + or - 4 x 10-17. This will be useful in converting the numerical values of some astronomical constants determined in the old IAU time scale barycentric dynamic time (TDB) to those in TCB. Also the paper will be useful when converting between TCB and TDB, i.e. the time scales themselves.

Fukushima, T.

1995-02-01

428

Time-Distance Helioseismology  

NASA Technical Reports Server (NTRS)

Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

Duvall, Thomas L., Jr.

2010-01-01

429

On Time  

NSDL National Science Digital Library

This online exhibit from a prominent American museum explores the character of time -- its impact on our daily lives and its ability to shape and reform human consciousness. The site is from the National Museum of American History and concentrates on how humans have measured time from 1700 to the present. The exhibit presents text and images describing the history of keeping time from the century immediately preceding the industrial revolution -- when sundials were still in use -- to our present age of digital access and a global village that never sleeps.

430

Journal of Geophysical Research Publications: Community Characteristics  

NASA Astrophysics Data System (ADS)

Do earth science publications differ by subfield or gender? To figure this out we analyzed publications in JGR Atmosphere, Oceans, and Solid Earth for the year 2000. We assumed that the first author exerted controlling influence over publication characteristics and then we looked at the number of co-authors, number of institutions represented by co-author affiliations, page length of the article, number of references cited, number of subject categories represented in the cited references, number of times the article was cited, and the time between the date the article was submitted and the date when it was accepted for publication. We found that, within each field, there was remarkable similarity between the publications led by women and those led by men. Interesting differences showed up between subfields: for example, Solid Earth authors use more references than do authors publishing in Atmosphere or Oceans.

Pfirman, S. L.; Porter, A.

2009-12-01

431

Thrombin Time  

MedlinePLUS

... 1. Can the thrombin time be performed in my doctor's office? With the exception of a PT ... DC. Pp 227-238. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson R, Pincus ...

432

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

433

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 ...

434

Time Management  

NSDL National Science Digital Library

This section of Mind Tools teaches you time management skills. These are the simple, practical techniques that have helped the leading people in business, sport and public service reach the pinnacles of their careers.

MindTools (MindTools)

2012-01-20

435

Time outs  

MedlinePLUS

... Time-out technique for discipline. Children's Health Network web site. http://www.childrenshealthnetwork.org/CRS/CRS/pa_ ... a break from negative behavior. Massachusetts Medical Society web site. http://www.massmed.org/patient-care/health- ...

436

Highly segmented, high resolution time-of-flight system  

SciTech Connect

The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

1991-12-31

437

Part-Time Faculty Handbook.  

ERIC Educational Resources Information Center

This document contains comprehensive information designed to orient the part-time faculty member to the College of the Mainland. Information included in the handbook covers the history and philosophy of the college; student and instructor rights; a description of social and economic characteristics of the students; a description of the faculty;…

College of the Mainland, Texas City, TX.

438

Timing in the Time Domain: Cygnus X-1  

E-print Network

Quantities characterizing temporal property, e.g. power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variability duration, and correlation between different characteristic quantities on different time scale can be studied in the time domain as well. The temporal analysis technique in the time domain is a powerful tool, particularly in studying rapid variability on short time scales (or in high frequencies). Results of studying variabilities of X-rays from Cyg X-1 with the analysis technique in the time domain and RXTE data reveal valuable clues to understanding production and propagation processes of X-rays and structure of accretion disk in the black hole system.

Ti-pei Li

2001-09-26

439

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.

440

About time  

NASA Technical Reports Server (NTRS)

Time has historically been a measure of progress of recurrent physical processes. Coordination of future actions, prediction of future events, and assigning order to events are three practical reasons for implementing clocks and signalling mechanisms. In large networks of computers, these needs lead to the problem of synchronizing the clocks throughout the network. Recent methods allow this to be done in large networks with precision around 1 millisecond despite mean message exchange times near 5 milliseconds. These methods are discussed.

Denning, Peter J.

1990-01-01