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Sample records for steady periodic water

  1. Locations, values, and uncertainties of hydraulic-head observations for the steady-state, prepumped period of the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set contains the locations, values, and uncertainties of 700 hydraulic-head observations used in the steady-state, prepumped period of...

  2. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    Science.gov (United States)

    Raz, O.; Subaşı, Y.; Jarzynski, C.

    2016-04-01

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents. To generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters—also known as a stochastic pump (SP)—reaches a periodic state with nonvanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems, we establish a mapping between nonequilibrium stationary states and stochastic pumps. Given a NESS characterized by a particular set of stationary probabilities, currents, and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: They show that stochastic pumps are able to mimic the behavior of nonequilibrium steady states, and vice versa, within the theoretical framework of discrete-state stochastic thermodynamics. Nonequilibrium steady states and stochastic pumps are often used to model, respectively, biomolecular motors driven by chemical reactions and artificial molecular machines steered by the variation of external, macroscopic parameters. Our results loosely suggest that anything a biomolecular machine can do, an artificial molecular machine can do equally well. We illustrate this principle by showing that kinetic proofreading, a NESS mechanism that explains the low error rates in biochemical reactions, can be effectively mimicked by a constrained periodic driving.

  3. Steady-state leaching of tritiated water from silica gel

    DEFF Research Database (Denmark)

    Das, H.A.; Hou, Xiaolin

    2009-01-01

    Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion.......Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion....

  4. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    Science.gov (United States)

    2016-08-29

    biochemical reactions , can be effectively mimicked by a constrained periodic driving. DOI: 10.1103/PhysRevX.6.021022 Subject Areas: Statistical...error rates in biochemical reactions such as protein synthesis. The system in kinetic proofreading is described by a discrete-state continuous-time... concentrations are constantly maintained out of equilibrium. Such a coupling modifies the Arrhenius rates : Denoting the rate matrix now by R (as it is not

  5. Immediate Analysis of Periodic Steady States in Switched DC-DC Converters via SPICE

    Directory of Open Access Journals (Sweden)

    D. Biolek

    2012-04-01

    Full Text Available The method of immediate analysis of periodic steady states in switched DC-DC converters operating in the continuous current mode is described. The initial conditions, which correspond to the periodic steady state, are found in the first step. They are used consequently for the conventional transient analysis. A special SPICE model of the converter finds automatically these initial conditions, which are then available within the transient analysis. The method works both for the well-known behavioral models of switched converters and also for models which employ complex nonlinear SPICE models of semiconductor switches.

  6. Algorithm for determining two-periodic steady-states in AC machines directly in time domain

    Directory of Open Access Journals (Sweden)

    Sobczyk Tadeusz J.

    2016-09-01

    Full Text Available This paper describes an algorithm for finding steady states in AC machines for the cases of their two-periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain despite of the fact that two-periodic waveforms are not repeated in any finite time interval. The basis for such an algorithm is a discrete differential operator that specifies the temporary values of the derivative of the two-periodic function in the selected set of points on the basis of the values of that function in the same set of points. It allows to develop algebraic equations defining the steady state solution reached in a chosen point set for the nonlinear differential equations describing the AC machines when electrical and mechanical equations should be solved together. That set of those values allows determining the steady state solution at any time instant up to infinity. The algorithm described in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.

  7. Prethermal Floquet Steady States and Instabilities in the Periodically Driven, Weakly Interacting Bose-Hubbard Model.

    Science.gov (United States)

    Bukov, Marin; Gopalakrishnan, Sarang; Knap, Michael; Demler, Eugene

    2015-11-13

    We explore prethermal Floquet steady states and instabilities of the weakly interacting two-dimensional Bose-Hubbard model subject to periodic driving. We develop a description of the nonequilibrium dynamics, at arbitrary drive strength and frequency, using a weak-coupling conserving approximation. We establish the regimes in which conventional (zero-momentum) and unconventional [(π,π)-momentum] condensates are stable on intermediate time scales. We find that condensate stability is enhanced by increasing the drive strength, because this decreases the bandwidth of quasiparticle excitations and thus impedes resonant absorption and heating. Our results are directly relevant to a number of current experiments with ultracold bosons.

  8. Exact solution to the steady-state dynamics of a periodically modulated resonator

    Directory of Open Access Journals (Sweden)

    Momchil Minkov

    2017-07-01

    Full Text Available We provide an analytic solution to the coupled-mode equations describing the steady-state of a single periodically modulated optical resonator driven by a monochromatic input. The phenomenology of this system was qualitatively understood only in the adiabatic limit, i.e., for low modulation speed. However, both in and out of this regime, we find highly non-trivial effects for specific parameters of the modulation. For example, we show complete suppression of the transmission even with zero detuning between the input and the static resonator frequency. We also demonstrate the possibility for complete, lossless frequency conversion of the input into the sideband frequencies, as well as for optimizing the transmitted signal towards a given target temporal waveform. The analytic results are validated by first-principle simulations.

  9. Well balancing of the SWE schemes for moving-water steady flows

    Science.gov (United States)

    Caleffi, Valerio; Valiani, Alessandro

    2017-08-01

    In this work, the exact reproduction of a moving-water steady flow via the numerical solution of the one-dimensional shallow water equations is studied. A new scheme based on a modified version of the HLLEM approximate Riemann solver (Dumbser and Balsara (2016) [18]) that exactly preserves the total head and the discharge in the simulation of smooth steady flows and that correctly dissipates mechanical energy in the presence of hydraulic jumps is presented. This model is compared with a selected set of schemes from the literature, including models that exactly preserve quiescent flows and models that exactly preserve moving-water steady flows. The comparison highlights the strengths and weaknesses of the different approaches. In particular, the results show that the increase in accuracy in the steady state reproduction is counterbalanced by a reduced robustness and numerical efficiency of the models. Some solutions to reduce these drawbacks, at the cost of increased algorithm complexity, are presented.

  10. Hydrocarbons on sea water: steady-state spreading signatures determined

    Directory of Open Access Journals (Sweden)

    Adriana Mazurek

    2007-09-01

    Full Text Available The spreading properties of several hydrocarbons (vegetable,engine, gear and crude oils on distilled and artificial seawater were determined under laboratory conditions using a noveloptical method. With the aid of Langmuir's equation, the geometricalsignatures of a discrete lens of each hydrocarbon droplet floatingon a water tank served to calculate the enteringE (31.30-94.18 mN m-1 and spreadingS (-3.50 to -57.49 mN m-1 coefficients, and equilibriumthicknesses t∞ (0.20-1.25 cm. They appeared to be in agreementwith the values derived from direct interfacial tension measurements (Wilhelmyplate and stalagmometer methods. Empirical relations of the normalized lensradius rL / rdrop and S on the water surface tensionγAW were postulated as being of significant value in oil spillassessment studies at sea. The parameters obtained together with the surfaceproperties of a natural surfactant-containing water body represent theprincipal input data required for modelling the spreading of asurface-tension-gradient-driven oil spill at sea.

  11. Visualizing ocular lens fluid dynamics using MRI: manipulation of steady state water content and water fluxes.

    Science.gov (United States)

    Vaghefi, Ehsan; Pontre, Beau P; Jacobs, Marc D; Donaldson, Paul J

    2011-08-01

    Studies using various MRI techniques have shown that a water-protein concentration gradient exists in the ocular lens. Because this concentration is higher in the core relative to the lens periphery, a gradient in refractive index is established in the lens. To investigate how the water-protein concentration profile is maintained, bovine lenses were incubated in different solutions, and changes in water-protein concentration ratio monitored using proton density weighted (PD-weighted) imaging in the absence and presence of heavy water (D(2)O). Lenses incubated in artificial aqueous humor (AAH) maintained the steady state water-protein concentration gradient, but incubating lenses in high extracellular potassium (KCl-AAH) or low temperature (Low T-AAH) caused a collapse of the gradient due to a rise in water content in the core of the lens. To visualize water fluxes, lenses were incubated in D(2)O, which acts as a contrast agent. Incubation in KCl-AAH and low T-AAH dramatically slowed the movement of D(2)O into the core but did not affect the movement of D(2)O into the outer cortex. D(2)O seemed to preferentially enter the lens cortex at the anterior and posterior poles before moving circumferentially toward the equatorial regions. This directionality of D(2)O influx into the lens cortex was abolished by incubating lenses in high KCl-AAH or low T-AAH, and resulted in homogenous influx of D(2)O into the outer cortex. Taken together, our results show that the water-protein concentration ratio is actively maintained in the core of the lens and that water fluxes preferentially enter the lens at the poles.

  12. Non-steady-state photoelectromotive force effect under linear and periodical phase modulation: application to detection of Doppler frequency shift.

    Science.gov (United States)

    Mansurova, S; Zarate, P Moreno; Rodriguez, P; Stepanov, S; Köber, S; Meerholz, K

    2012-02-01

    Non-steady-state photoelectromotive force effect in the presence of periodical and linear phase shift was investigated both theoretically and experimentally. It was shown that superposition of oscillating and linear movements of the interference pattern leads to the appearance of the sharp peak in the frequency dependence of the photoelectromotive force output current when the frequency of periodical modulation matches the frequency of the linear phase shift. We demonstrated experimentally that this effect can be used for determination of a Doppler frequency shift between signal and reference beam.

  13. Impact of hot-carrier degradation on the Low-Frequency Noise in MOSFETs under steady-state and periodic Large-Signal Excitation

    NARCIS (Netherlands)

    Kolhatkar, J.S.; Hoekstra, E.; Hof, A.J.; Salm, Cora; Schmitz, Jurriaan; Wallinga, Hans

    2005-01-01

    This letter reports the diagnostic power of the low-frequency noise analysis (steady-state and periodic large-signal excitation) in MOSFETs subjected to hot-carrier degradation. The LF noise under periodic large-signal excitation is shown to increase more rapidly than the LF noise in steady-state.

  14. Real-time dynamic hydraulic model for water distribution networks: steady state modelling

    CSIR Research Space (South Africa)

    Osman, Mohammad S

    2016-09-01

    Full Text Available steady state hydraulic model that will be used within a real-time dynamic hydraulic model (DHM). The Council for Scientific and Industrial Research (CSIR) water distribution network (WDN) is used as a pilot study for this purpose. A hydraulic analysis...

  15. Accurate and efficient computation of steady water flow with surface waves and turbulence

    NARCIS (Netherlands)

    Wackers, J.; Koren, B.

    2006-01-01

    A surface capturing method is developed for steady water-air flow with gravity. Second-order accuracy is obtained with flux limiting and turbulence is modeled with Menter's model. The model is solved efficiently with a combination of multigrid and defect correction. Results for two test cases

  16. Planet X and the origins of the shower and steady state flux of short-period comets

    Energy Technology Data Exchange (ETDEWEB)

    Matese, J.J.; Whitmire, D.P.

    1986-01-01

    An extensive analysis of the planet X model is presented. Unlike prior analyses, it takes into account the fact that only those comets scattered directly into the zones of influence (ZOI) of Saturn and Jupiter can contribute to a shower whose duration is in agreement with observation. It is predicted that some of the comets scattered directly into ZOI of Uranus and Neptune wiwll evolve on time scales of about 100 million years into the steady state flux of short-period comets. The absolute numbers of shower and steady state comets were found to be comparable with the known terrestrial cratering rate, assuming the existence of long-lived extinct comet cores. Canonical planet X model parameters are given, and it is suggested that planet X, in its present orbit, can create the requisite density gradient of comets near perihelion and aphelion during the lifetime of the solar system. It is concluded that the existence of planet X and the comet disk can explain the origin of the steady state flux of short-period comets over a wide range of parameters. 43 references

  17. Steady-state time-periodic finite element analysis of a brushless DC motor drive considering motion

    Directory of Open Access Journals (Sweden)

    Jagieła Mariusz

    2015-09-01

    Full Text Available This paper aims at providing a framework for comprehensive steady-state time-domain analysis of rotating machines considering motion. The steady-state waveforms of electromagnetic and circuit quantities are computed via iterative solution of the nonlinear field-circuit-and-motion problem with constraints of time periodicity. The cases with forced speed and forced load torque are considered. A comparison of execution times with a conventional time-stepping transient model is carried out for two different machines. The numerical stability of a time-periodic model with forced speed is shown to be worse than that of traditional transient time-stepping one, although the model converges within a reasonable number of iterations. This is not the case if forced load via equation of mechanical balance is accounted for. To ensure convergence of the iterative process the physical equation of motion is replaced by the fixed-point equation. In this way the model delivers time-periodic solutions regarding not only the electromagnetic quantities but also the rotational speed.

  18. Steady-State Diffusion of Water through Soft-Contact LensMaterials

    Energy Technology Data Exchange (ETDEWEB)

    Fornasiero, Francesco; Krull, Florian; Radke, Clayton J.; Prausnitz, JohnM.

    2005-01-31

    Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through soft-contact-lens materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens{trademark} One Day, hilafilcon A, water content at saturation W{sub 10} = 70 weight %) and a silicone hydrogel material (PureVision{trademark}, balafilcon A, W{sub 10} = 36 %), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional HEMA-SCL (W{sub 10} = 38 %) hydrogel are reexamined and compared with those for SofLens{trademark} One Day and PureVision{trademark} hydrogels. Measured steady-state water fluxes are largest for SofLens{trademark} One Day, followed by PureVision{trademark} and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when the relative humidity is below 55-75%. Steady-state water-fluxes are interpreted through an extended Maxwell-Stefan diffusion model for a mixture of species starkly different in size. Thermodynamic nonideality is considered through Flory-Rehner polymer-solution theory. Shrinking/swelling is self-consistently modeled by conservation of the total polymer mass. Fitted Maxwell-Stefan diffusivities increase significantly with water concentration in the contact lens.

  19. Augmented Riemann solvers for the shallow water equations over variable topography with steady states and inundation

    Science.gov (United States)

    George, David L.

    2008-03-01

    We present a class of augmented approximate Riemann solvers for the shallow water equations in the presence of a variable bottom surface. These belong to the class of simple approximate solvers that use a set of propagating jump discontinuities, or waves, to approximate the true Riemann solution. Typically, a simple solver for a system of m conservation laws uses m such discontinuities. We present a four wave solver for use with the the shallow water equations—a system of two equations in one dimension. The solver is based on a decomposition of an augmented solution vector—the depth, momentum as well as momentum flux and bottom surface. By decomposing these four variables into four waves the solver is endowed with several desirable properties simultaneously. This solver is well-balanced: it maintains a large class of steady states by the use of a properly defined steady state wave—a stationary jump discontinuity in the Riemann solution that acts as a source term. The form of this wave is introduced and described in detail. The solver also maintains depth non-negativity and extends naturally to Riemann problems with an initial dry state. These are important properties for applications with steady states and inundation, such as tsunami and flood modeling. Implementing the solver with LeVeque's wave propagation algorithm [R.J. LeVeque, Wave propagation algorithms for multi-dimensional hyperbolic systems, J. Comput. Phys. 131 (1997) 327-335] is also described. Several numerical simulations are shown, including a test problem for tsunami modeling.

  20. Steady state method to determine unsaturated hydraulic conductivity at the ambient water potential

    Science.gov (United States)

    HUbbell, Joel M.

    2014-08-19

    The present invention relates to a new laboratory apparatus for measuring the unsaturated hydraulic conductivity at a single water potential. One or more embodiments of the invented apparatus can be used over a wide range of water potential values within the tensiometric range, requires minimal laboratory preparation, and operates unattended for extended periods with minimal supervision. The present invention relates to a new laboratory apparatus for measuring the unsaturated hydraulic conductivity at a single water potential. One or more embodiments of the invented apparatus can be used over a wide range of water potential values within the tensiometric range, requires minimal laboratory preparation, and operates unattended for extended periods with minimal supervision.

  1. Deep water periodic waves as Hamiltonian relative equilibria

    NARCIS (Netherlands)

    van Groesen, Embrecht W.C.; Lie She Liam, L.S.L.; Lakhturov, I.; Andonowati, A.; Biggs, N.

    2007-01-01

    We use a recently derived KdV-type of equation for waves on deep water to study Stokes waves as relative equilibria. Special attention is given to investigate the cornered Stokes-120 degree wave as a singular solution in the class of smooth steady wave profiles.

  2. In-pipe water quality monitoring in water supply systems under steady and unsteady state flow conditions: a quantitative assessment.

    Science.gov (United States)

    Aisopou, Angeliki; Stoianov, Ivan; Graham, Nigel J D

    2012-01-01

    Monitoring the quality of drinking water from the treatment plant to the consumers tap is critical to ensure compliance with national standards and/or WHO guideline levels. There are a number of processes and factors affecting the water quality during transmission and distribution which are little understood. A significant obstacle for gaining a detailed knowledge of various physical and chemical processes and the effect of the hydraulic conditions on the water quality deterioration within water supply systems is the lack of reliable and low-cost (both capital and O & M) water quality sensors for continuous monitoring. This paper has two objectives. The first one is to present a detailed evaluation of the performance of a novel in-pipe multi-parameter sensor probe for reagent- and membrane-free continuous water quality monitoring in water supply systems. The second objective is to describe the results from experimental research which was conducted to acquire continuous water quality and high-frequency hydraulic data for the quantitative assessment of the water quality changes occurring under steady and unsteady-state flow conditions. The laboratory and field evaluation of the multi-parameter sensor probe showed that the sensors have a rapid dynamic response, average repeatability and unreliable accuracy. The uncertainties in the sensor data present significant challenges for the analysis and interpretation of the acquired data and their use for water quality modelling, decision support and control in operational systems. Notwithstanding these uncertainties, the unique data sets acquired from transmission and distribution systems demonstrated the deleterious effect of unsteady state flow conditions on various water quality parameters. These studies demonstrate: (i) the significant impact of the unsteady-state hydraulic conditions on the disinfectant residual, turbidity and colour caused by the re-suspension of sediments, scouring of biofilms and tubercles from the

  3. Instabilities in fluid layers and in reaction-diffusion systems: Steady states, time-periodic solutions, non-periodic attractors, and related convective and otherwise non-linear phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Velarde, M.

    1977-07-01

    Thermo convective instabilities in horizontal fluid layers are discussed with emphasis on the Rayleigh-Bernard model problem. Steady solutions and time-dependent phenomena (relaxation oscillations and transition to turbulence) are studied within the nonlinear Boussinesq-Oberbeck approximation. Homogeneous steady solutions, limit cycles, and inhomogeneous (ordered) spatial structures are also studied in simple reaction-diffusion systems. Lastly, the non-periodic attractor that appears at large Rayleigh numbers in the truncated Boussinesq-Oberbeck model of Lorenz, is constructed, and a discussion of turbulent behavior is given. (Author) 105 refs.

  4. Steady-state pharmacokinetics of once-daily cyclobenzaprine extended release: a randomized, double-blind, 2-period crossover study in healthy volunteers.

    Science.gov (United States)

    Darwish, Mona; Hellriegel, Edward T

    2011-06-01

    The single-dose pharmacokinetic profile of cyclobenzaprine extended-release (CER) has been previously characterized and compared with the pharmacokinetics of cyclobenzaprine immediate-release (CIR) administered 3 times daily for 3 doses. The objective of this study was to characterize the multiple-dose pharmacokinetic properties of once-daily CER 30 mg and CIR 10 mg TID formulations in healthy volunteers. In this double-blind, single-center, 2-period crossover study, healthy subjects were randomized to dosing sequences with once-daily CER 30 mg or CIR 10 mg TID for 7 days. Subjects crossed over to the alternative regimen following a 14-day washout period. Pharmacokinetic assessments at steady state included area under the plasma cyclobenzaprine concentration-time curve over the dosing interval (AUC(0-τ,ss)), peak plasma cyclobenzaprine concentration (C(max,ss)), time to observed C(max) (T(max,ss)), observed minimum cyclobenzaprine concentration (C(min,ss)), average cyclobenzaprine concentration (C(avg,ss)), accumulation ratio (R(ac)), and terminal elimination half-life (t(½)). Tolerability and safety assessments were conducted. A total of 36 subjects were randomized; 34 completed both dosing periods (1 subject was lost to follow-up, 1 withdrew consent). Steady state was reached for CER 30 mg on day 7. Mean C(max,ss), C(min,ss), and C(avg,ss) were 41.1, 21.4, and 31.4 ng/mL, respectively. The median T(max,ss) for CER 30 mg was 7.0 hours, with a mean t(½) of 34.8 hours. At steady state, CER produced a sustained plasma cyclobenzaprine concentration with a single peak in plasma concentration during the 24-hour dose interval. The R(ac) for CER was 2.65. Because of a protocol violation (insufficient data), no steady-state pharmacokinetic assessments could be performed for CIR. Most adverse events were mild or moderate in intensity. Somnolence was the most frequently reported adverse event (100% of subjects) in those receiving CER, followed by dry mouth (58

  5. Extended period simulation (EPS) modelling of urban water ...

    African Journals Online (AJOL)

    Water distribution network was constructed, calibrated and validated for extended period simulation studies using the network's physical, operational, calibration and validation data. The model was then applied to evaluate: (i) effects of fluctuating water demand on system storage over 24 hour period and (ii) level of service ...

  6. Efficient computation of steady, 3D water-wave patterns, application to hovercraft-type flows

    NARCIS (Netherlands)

    M.R. Lewis; B. Koren (Barry)

    2002-01-01

    textabstractNumerical methods for the computation of stationary free surfaces is the subject of much current research in computational engineering. The present report is directed towards free surfaces in maritime engineering. Of interest here are the long steady waves generated by hovercraft and

  7. Modelling non-steady-state isotope enrichment of leaf water in a gas-exchange cuvette environment.

    Science.gov (United States)

    Song, Xin; Simonin, Kevin A; Loucos, Karen E; Barbour, Margaret M

    2015-12-01

    The combined use of a gas-exchange system and laser-based isotope measurement is a tool of growing interest in plant ecophysiological studies, owing to its relevance for assessing isotopic variability in leaf water and/or transpiration under non-steady-state (NSS) conditions. However, the current Farquhar & Cernusak (F&C) NSS leaf water model, originally developed for open-field scenarios, is unsuited for use in a gas-exchange cuvette environment where isotope composition of water vapour (δv ) is intrinsically linked to that of transpiration (δE ). Here, we modified the F&C model to make it directly compatible with the δv -δE dynamic characteristic of a typical cuvette setting. The resultant new model suggests a role of 'net-flux' (rather than 'gross-flux' as suggested by the original F&C model)-based leaf water turnover rate in controlling the time constant (τ) for the approach to steady sate. The validity of the new model was subsequently confirmed in a cuvette experiment involving cotton leaves, for which we demonstrated close agreement between τ values predicted from the model and those measured from NSS variations in isotope enrichment of transpiration. Hence, we recommend that our new model be incorporated into future isotope studies involving a cuvette condition where the transpiration flux directly influences δv . There is an increasing popularity among plant ecophysiologists to use a gas-exchange system coupled to laser-based isotope measurement for investigating non-steady state (NSS) isotopic variability in leaf water (and/or transpiration); however, the current Farquhar & Cernusak (F&C) NSS leaf water model is unsuited for use in a gas-exchange cuvette environment due to its implicit assumption of isotope composition of water vapor (δv ) being constant and independent of that of transpiration (δE ). In the present study, we modified the F&C model to make it compatible with the dynamic relationship between δv and δE as is typically associated

  8. Rapid phase-modulated water-excitation steady-state free precession for fat-suppressed cine cardiovascular MR

    Directory of Open Access Journals (Sweden)

    Raman Subha V

    2008-05-01

    Full Text Available Abstract Background The purpose of this article is to describe a steady-state free precession (SSFP sequence for fat-suppressed cine cardiovascular magnetic resonance (CMR. A rapid phase-modulated binomial water-excitation (WE pulse is utilized to minimize repetition time and acquisition time. Methods Three different water-excitation pulses were combined with cine-SSFP for evaluation. The frequency response of each sequence was simulated and examined in phantom imaging studies. The ratio of fat to water signal amplitude was measured in phantoms to evaluate the fat-suppression capabilities of each method. Six volunteers underwent CMR of the heart at 1.5T to compare retrospectively-gated cine-SSFP with and without water-excitation. The ratio of fat to myocardium signal amplitude was measured for conventional cine-SSFP and phase-modulated WE-SSFP. The proposed WE-SSFP method was tested in one patient referred for CMR to characterize a cardiac mass. Results and discussion The measured frequency response in a phantom corresponded to the numerical Bloch equation simulation demonstrating the widened stop-band around the fat resonant frequency for all water-excitation pulses tested. In vivo measurements demonstrated that a rapid, phase-modulated water-excitation pulse significantly reduced the signal amplitude ratio of fat to myocardium from 6.92 ± 2.9 to 0.8 ± 0.13 (mean ± SD without inducing any perceptible artifacts in SSFP cine CMR. Conclusion fat-suppression can be achieved in SSFP cine CMR while maintaining steady-state equilibrium using rapid, phase modulated, binomial water-excitation pulses.

  9. On periodic geophysical water flows with discontinuous vorticity in the equatorial f-plane approximation

    Science.gov (United States)

    Martin, Calin Iulian

    2017-12-01

    We are concerned here with geophysical water waves arising as the free surface of water flows governed by the f-plane approximation. Allowing for an arbitrary bounded discontinuous vorticity, we prove the existence of steady periodic two-dimensional waves of small amplitude. We illustrate the local bifurcation result by means of an analysis of the dispersion relation for a two-layered fluid consisting of a layer of constant non-zero vorticity γ1 adjacent to the surface situated above another layer of constant non-zero vorticity γ2≠γ1 adjacent to the bed. For certain vorticities γ1,γ2, we also provide estimates for the wave speed c in terms of the speed at the surface of the bifurcation inducing laminar flows. This article is part of the theme issue 'Nonlinear water waves'.

  10. A steady-state analysis of the temperature responses of water vapor and aerosol lifetimes

    NARCIS (Netherlands)

    Roelofs, G.J.H.|info:eu-repo/dai/nl/100925375

    2013-01-01

    The dominant removal mechanism of soluble aerosol is wet deposition. The atmospheric lifetime of aerosol, relevant for aerosol radiative forcing, is therefore coupled to the atmospheric cycling time of water vapor. This study investigates the coupling between water vapor and aerosol lifetimes in a

  11. Analytical approximation and numerical simulations for periodic travelling water waves

    Science.gov (United States)

    Kalimeris, Konstantinos

    2017-12-01

    We present recent analytical and numerical results for two-dimensional periodic travelling water waves with constant vorticity. The analytical approach is based on novel asymptotic expansions. We obtain numerical results in two different ways: the first is based on the solution of a constrained optimization problem, and the second is realized as a numerical continuation algorithm. Both methods are applied on some examples of non-constant vorticity. This article is part of the theme issue 'Nonlinear water waves'.

  12. Steadiness of a “water bell” surface to a destruction at a flow around of the thin rods assembly

    Directory of Open Access Journals (Sweden)

    Slesareva Ekaterina

    2015-01-01

    Full Text Available The experimental research of hydrodynamic stability of a dome-shaped film liquid at a flow around a thin plate has been carried out. Experiments were carry out with a film in shape a «water bell». The film was formed by a leak-in jet of water width 10 mm on a hard disk with diameter 14.5 mm. The width of a plate ζ changed from 0.05 to 3.5 mm. The plate placed along or across relative to the vector of velocity of a liquid in a film. Experiments have shown, that stability of a film of liquid at a flow around the plate is defined by velocity of water and a thickness of a film δ in front of the rod. It is shown, that for the appointed value of Reynolds number Reδ probably continuous flow at a flow around the plate, if Weber number Weζ less than threshold value. The criterion of steadiness a film of the «water bell» by a surface destruction at a flow around the rod is determined on the transverse size of the rod relative to the vector of velocity of a liquid.

  13. Analytical approximation and numerical simulations for periodic travelling water waves.

    Science.gov (United States)

    Kalimeris, Konstantinos

    2018-01-28

    We present recent analytical and numerical results for two-dimensional periodic travelling water waves with constant vorticity. The analytical approach is based on novel asymptotic expansions. We obtain numerical results in two different ways: the first is based on the solution of a constrained optimization problem, and the second is realized as a numerical continuation algorithm. Both methods are applied on some examples of non-constant vorticity.This article is part of the theme issue 'Nonlinear water waves'. © 2017 The Author(s).

  14. Novel Slope Source Term Treatment for Preservation of Quiescent Steady States in Shallow Water Flows

    Directory of Open Access Journals (Sweden)

    Khawar Rehman

    2016-10-01

    Full Text Available This paper proposes a robust method for modeling shallow-water flows and near shore tsunami propagation, applicable for both simple and complex geometries with uneven beds. The novel aspect of the model includes the introduction of a new method for slope source terms treatment to preserve quiescent equilibrium over uneven topographies, applicable to both structured and unstructured mesh systems with equal accuracy. Our model is based on the Godunov-type finite volume numerical approximation. Second-order spatial and temporal accuracy is achieved through high resolution gradient reconstruction and the predictor-corrector method, respectively. The approximate Riemann solver of Harten, Lax, and van Leer with contact wave restoration (HLLC is used to compute fluxes. Comparisons of the model’s results with analytical, experimental, and published numerical solutions show that the proposed method is capable of accurately predicting experimental and real-time tsunami propagation/inundation, and dam-break flows over varying topographies.

  15. Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

    Science.gov (United States)

    Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

    2014-01-01

    Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

  16. Two-dimensional, steady-state model of ground-water flow, Nevada Test Site and vicinity, Nevada-California

    Science.gov (United States)

    Waddell, R.K.

    1982-01-01

    A two-dimensional, steady-state model of ground-water flow beneath the Nevada Test Site and vicinity has been developed using inverse techniques. The area is underlain by clastic and carbonate rocks of Precambrian and Paleozoic age and by volcanic rocks and alluvium of Tertiary and Quaternary age that have been juxtaposed by normal and strike-slip faulting. Aquifers are composed of carbonate and volcanic rocks and alluvium. Characteristics of the flow system are determined by distribution of low-conductivity rocks (barriers); by recharge originating in the Spring Mountains, Pahranagat, Timpahute, and Sheep Ranges, and in Pahute Mesa; and by underflow beneath Pahute Mesa from Gold Flat and Kawich Valley. Discharge areas (Ash Meadows, Oasis Valley, Alkali Flat, and Furnace Creek Ranch) are upgradient from barriers. Sensitivities of simulated hydraulic heads and fluxes to variations in model parameters were calculated to guide field studies and to help estimate errors in predictions from transport modeling. Hydraulic heads and fluxes are very sensitive to variations in the greater magnitude recharge/discharge terms. Transmissivity at a location may not be the most important transmissivity for determining flux there. Transmissivities and geometries of large barriers that impede flow from Pahute Mesa have major effects on fluxes elsewhere; as their transmissivities are decreased, flux beneath western Jackass Flats and Yucca Mountains is increased as water is diverted around the barriers. Fortymile Canyon is underlain by highly transmissive rocks that cause potentiometric contours to vee upgradient; increasing their transmissivity increases flow through them, and decreases it beneath Yucca Mountain. (USGS)

  17. Diurnal cycles in water quality across the periodic table

    Science.gov (United States)

    Kirchner, James

    2014-05-01

    Diurnal cycles in water quality can provide important clues to the processes that regulate aquatic chemistry, but they often are masked by longer-term, larger-amplitude variability, making their detection and quantification difficult. Here I outline methods that can detect diurnal cycles even when they are massively obscured by statistically ill-behaved noise. I demonstrate these methods using high-frequency water quality data from the Plylimon catchment in mid-Wales (Neal et al., 2013; Kirchner and Neal, 2013). Several aspects combine to make the Plynlimon data set unique worldwide. Collected at 7-hour intervals, the Plynlimon data set is much more densely sampled than typical long-term weekly or monthly water quality data. This 7-hour sampling was also continued for two years, much longer than typical intensive sampling campaigns, and the resulting time series encompass a wide range of climatic and hydrological conditions. Furthermore, each sample was analyzed for a wide range of solutes with diverse sources in the natural environment. However, the 7-hour sampling frequency is both coarse and irregular in comparison to diurnal cycles, making their detection and quantification difficult. Nonetheless, the methods outlined here enable detection of statistically significant diurnal cycles in over 30 solutes at Plynlimon, including alkali metals (Li, Na, K, Rb, and Cs), alkaline earths (Be, Mg, Ca, Sr, and Ba), transition metals (Al, Ti, Mn, Fe, Co, Ni, Zn, Mo, Cd, and Pb), nonmetals (B, NO3, Si, As, and Se), lanthanides and actinides (La, Ce, Pr, and U), as well as total dissolved nitrogen (TDN), dissolved organic carbon (DOC), Gran alkalinity, pH, and electrical conductivity. These solutes span every row of the periodic table, and more than six orders of magnitude in concentration. Many of these diurnal cycles are subtle, representing only a few percent, at most, of the total variance in the concentration time series. Nonetheless they are diagnostically useful

  18. Lateral boundary of the steady-state ground-water flow model by D'Agnese and others (2002), Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the lateral boundary of the area simulated by the steady-state ground-water flow model of the Death Valley regional ground-water flow...

  19. Meta-analysis assessing potential of steady-state chlorophyll fluorescence for remote sensing detection of plant water, temperature and nitrogen stress

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Malenovský, Z.; Olejníčková, Julie; Gallé, A.; Rascher, U.; Mohammed, G.

    2015-01-01

    Roč. 168, oct (2015), s. 420-436 ISSN 0034-4257 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : steady-state chlorophyll fluorescence * passive sun-induced fluorescence * active laser-induced fluorescence * photosynthesis * stress * water * temperature * nitrogen * random-effects meta-analysis * FLEX satellite mission Subject RIV: EH - Ecology, Behaviour Impact factor: 5.881, year: 2015

  20. Periodic fluctuations in deep water formation due to sea ice

    Science.gov (United States)

    Saha, R.

    2012-12-01

    During the last ice age, several abrupt warming events took place, known as Dansgaard-Oeschger (D-O) events. Their effects were felt globally, although the North Atlantic experienced the largest temperature increase. The leading hypothesis to explain their occurrence postulates that the warming was caused by abrupt disruptions of the North Atlantic Current due to meltwater discharge from destabilized ice sheets (Heinrich events). However, the number of warming events outnumber the those of ice-sheet collapse. Thus, the majority of D-O events are not attributed to surface freshwater anomalies, and the underlying mechanism behind their occurrence remain unexplained. Using a simple dynamical model of sea ice and an overturning circulation, I show the existence of self-sustained relaxation oscillations in the overturning circulation. The insulating effect of sea ice is shown to paradoxically lead to a net loss of heat from the top layer of the polar ocean when sea ice retreats. Repeated heat loss results in a denser top layer and a destabilized water column, which triggers convection. The convective state pulls the system out of its preferred mode of circulation, setting up relaxation oscillations. The period of oscillations in this case is linked to the geometry of the ocean basin, if solar forcing is assumed to remain constant. If appropriate glacial freshwater forcing is applied to the model, a pattern of oscillation is produced that bears remarkable similarity to the observed fluctuations in North Atlantic climate between 50,000 and 30,000 years before present.; Comparison of NGRIP δ 18-O (proxy for near surface air temperature) between 50,000 and 30,000 years before present, showing Bond cycles (left) with the model output when forced with appropriate glacial freshwater forcing (right).

  1. Maritime Crime in Nigeria and Waters Beyond Analysing the Period ...

    African Journals Online (AJOL)

    Incidents of maritime crime in Nigerian waters have become of punctuated interest recently, with maritime criminals finding the water spaces of the country conducive for their activities, and these waters thus becoming some of the most dangerous in the world. This paper considers maritime crime alongside the rise of the oil ...

  2. Neutron scattering study of water confined in periodic mesoporous organosilicas

    Science.gov (United States)

    Levy, Esthy; Kay Chan, Lok; Yu, Dehong; Marek Koza, Michael; Mastai, Yitzhak; Ford, R. C.; Li, Jichen

    2010-07-01

    A series of quasi-elastic neutron scattering measurements were performed using IN6 at the Institute Laue Langevin for a mesoporous organosilica material with phenyl functions, called phenyltriethoxysilane (PTES). The aim of the experiment was to study the diffusion dynamics of nano-scale water clusters inside the hydrophobic pores as a function of temperature and hydration. By fitting the Debye-Waller factor, the data show clearly the different behavior between water, both inside and outside the hydrophobic pores, which resembles bulk water. The mean thermal displacement of the external water increases with T almost linearly up to 353 K, while the internal water quickly reaches the maximum at T˜323 K, indicating the confinement by an averaged pore diameter of the porous organosilica.

  3. Numerical Investigation of the Influence of Water Jumping on the Local Scour beneath a Pipeline under Steady Flow

    Directory of Open Access Journals (Sweden)

    Fei Fan

    2017-08-01

    Full Text Available Rigid-lid approximation is usually used to replace the free surface in scour simulation. The influence of the rigid lid assumption on the prediction precision of scour hole in steady flow is studied in this paper. Firstly, a local scour model was constructed based on the open sources Computational Fluid Dynamics (CFD model OpenFOAM, where both the bed load and suspended load were considered. In the present model, the bed shear stress was calculated by the Newton shear stress formula, instead of the traditional calculation method with the assumption that the flow velocity in vertical direction complies with a logarithmic distribution. The Volume of Fluid (VOF method was used to capture the free surface and a moving-mesh method was used to track the change of bed surface. Then, several experiments were chosen to validate the model, and the modeling results fitted well with the measured data. Lastly, the effect of the rigid lid assumption on surface elevation, bed shear stress and the profile of the scour hole in steady flow are studied. The result shows that the surface elevation suffers a drop above the pipeline, and the difference of surface elevation between the upstream and downstream increases with decreasing dimensionless depth. Compared with the free surface condition, the bed shear stress and scour hole depth computed with the rigid lid approximation were underestimated.

  4. Critical loads of acid deposition for wilderness lakes in the sierra nevada (california) estimated by the steady-state water chemistry model

    OpenAIRE

    Shaw, GD; Cisneros, R; Schweizer, D; Sickman, JO; Fenn, ME

    2014-01-01

    Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (mean specific conductance=8.0 ?S cm?1) and characterized by low acid neutralizing capacity (ANC; mean= 56.8 ?eq L?1). Two variant...

  5. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets

    Science.gov (United States)

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak

    2015-01-01

    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet–height and diameter– and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials. PMID:26354891

  6. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets.

    Science.gov (United States)

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak

    2015-09-10

    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet-height and diameter- and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials.

  7. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets

    Science.gov (United States)

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, Youngpak

    2015-09-01

    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet-height and diameter- and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials.

  8. Water temperatures in select nearshore environments of the Colorado River in Grand Canyon, Arizona, during the Low Steady Summer Flow experiment of 2000

    Science.gov (United States)

    Vernieu, William S.; Anderson, Craig R.

    2013-01-01

    Water releases from Glen Canyon Dam, Arizona, are the primary determinant of streamflow, sediment transport, water quality, and aquatic and riparian habitat availability in the Colorado River downstream of the dam in Grand Canyon. The presence and operation of the dam have transformed the seasonally warm Colorado River into a consistently cold river because of hypolimnetic, or deep-water, releases from the penstock withdrawal structures on the dam. These releases have substantially altered the thermal regime of the downstream riverine environment. This, in turn, has affected the biota of the river corridor, particularly native and nonnative fish communities and the aquatic food web. In the spring and summer of 2000, a Low Steady Summer Flow experiment was conducted by the U.S. Geological Survey and the Bureau of Reclamation to evaluate the effects of the experimental flow on physical and biological resources of the Colorado River ecosystem downstream from Glen Canyon Dam to Lake Mead on the Arizona-Nevada border. This report describes the water temperatures collected during the experimental flow from 14 nearshore sites in the river corridor in Grand Canyon to assess the effects of steady releases on the thermal dynamics of nearshore environments. These nearshore areas are characterized by low-velocity flows with some degree of isolation from the higher velocity flows in the main channel and are hypothesized to be important rearing environments for young native fish. Water-temperature measurements were made at 14 sites, ranging from backwater to open-channel environments. Warming during daylight hours, relative to main-channel temperatures, was measured at all sites in relation to the amount of isolation from the main-channel current. Boat traffic, amount of direct solar radiation, and degree of isolation from the main-channel current appear to be the primary factors affecting the differential warming of the nearshore environment.

  9. An analytical study on nested flow systems in a Tóthian basin with a periodically changing water table

    Science.gov (United States)

    Zhao, Ke-Yu; Jiang, Xiao-Wei; Wang, Xu-Sheng; Wan, Li; Wang, Jun-Zhi; Wang, Heng; Li, Hailong

    2018-01-01

    Classical understanding on basin-scale groundwater flow patterns is based on Tóth's findings of a single flow system in a unit basin (Tóth, 1962) and nested flow systems in a complex basin (Tóth, 1963), both of which were based on steady state models. Vandenberg (1980) extended Tóth (1962) by deriving a transient solution under a periodically changing water table in a unit basin and examined the flow field distortion under different dimensionless response time, τ∗. Following Vandenberg's (1980) approach, we extended Tóth (1963) by deriving the transient solution under a periodically changing water table in a complex basin and examined the transient behavior of nested flow systems. Due to the effect of specific storage, the flow field is asymmetric with respect to the midline, and the trajectory of internal stagnation points constitutes a non-enclosed loop, whose width decreases when τ∗ decreases. The distribution of the relative magnitude of hydraulic head fluctuation, Δh∗ , is dependent on the horizontal distance away from a divide and the depth below the land surface. In the shallow part, Δh∗ decreases from 1 at the divide to 0 at its neighboring valley under all τ∗, while in the deep part, Δh∗ reaches a threshold, whose value decreases when τ∗ increases. The zones with flowing wells are also found to change periodically. As water table falls, there is a general trend of shrinkage in the area of zones with flowing wells, which has a lag to the declining water table under a large τ∗. Although fluxes have not been assigned in our model, the recharge/discharge flux across the top boundary can be obtained. This study is critical to understand a series of periodically changing hydrogeological phenomena in large-scale basins.

  10. Breath-held MR cholangiopancreatography (MRCP) using a 3D Dixon fat-water separated balanced steady state free precession sequence.

    Science.gov (United States)

    Glockner, James F; Saranathan, Manojkumar; Bayram, Ersin; Lee, Christine U

    2013-10-01

    A novel 3D breath-held Dixon fat-water separated balanced steady state free precession (b-SSFP) sequence for MR cholangiopancreatography (MRCP) is described and its potential clinical utility assessed in a series of patients. The main motivation is to develop a robust breath-held alternative to the respiratory gated 3D Fast Spin Echo (FSE) sequence, the current clinical sequence of choice for MRCP. Respiratory gated acquisitions are susceptible to motion artifacts and blurring in patients with significant diaphragmatic drift, erratic respiratory rhythms or sleep apnea. A two point Dixon fat-water separation scheme was developed which eliminates signal loss arising from B0 inhomogeneity effects and minimizes artifacts from perturbation of the b-SSFP steady state. Preliminary results from qualitative analysis of 49 patients demonstrate robust performance of the 3D Dixon b-SSFP sequence with diagnostic image quality acquired in a 20-24s breath-hold. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Ex-Stream: A MATLAB program for calculating fluid flux through sediment-water interfaces based on steady and transient temperature profiles

    Science.gov (United States)

    Swanson, Travis E.; Cardenas, M. Bayani

    2011-10-01

    Temperature is a useful environmental tracer for quantifying movement and exchange of water and heat through and near sediment-water interfaces (SWI). Heat tracing involves analyzing temperature time series or profiles from temperature probes deployed in sediments. Ex-Stream is a MATLAB program that brings together two transient and two steady one-dimensional coupled heat and fluid flux analytical models. The program includes a graphical user interface, a detailed user manual, and postprocessing capabilities that enable users to extract fluid fluxes from time-series temperature observations. Program output is written to comma-separated values files, displayed within the MATLAB command window, and may be optionally plotted. The models that are integrated into Ex-Stream can be run collectively, allowing for direct comparison, or individually.

  12. Studies on the steady shear flow behavior and chemical properties of water-soluble polysaccharide from Ziziphus lotus fruit.

    Science.gov (United States)

    Adeli, Mostafa; Samavati, Vahid

    2015-01-01

    The extraction of water-soluble polysaccharide from Ziziphus lotus fruit (WPZL) was performed by ultrasonic-assisted extraction method. A Box-Behnken design (BBD) was applied to evaluate the effects of three independent variables (ultrasonic power (X1: 70-100 W), extraction time (X2: 10-30 min), extraction temperature (X3: 55-95 °C), and water to raw material ratio (X4: 5-25)) on the extraction yield of APH. The effect of temperature and concentration on flow behavior of gum solution was studied. WPZL solutions exhibited shear-thinning non-Newtonian flow behavior for concentrations above 0.5% (w/v). The viscosity of fully hydrated gum solutions decreased as temperature increase. The correlation analysis of the mathematical-regression model indicated that quadratic polynomial model could be employed to optimize the extraction of WPZL. The optimal conditions to obtain the highest extraction of WPZL (13.398 ± 0.019%) were as follows: ultrasonic power, 88.77 W; extraction time, 29.96 min, extraction temperature, 77.73 °C and water to raw material ratio 24.44 mL/g. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Cartilage imaging at 3.0T with gradient refocused acquisition in the steady-state (GRASS) and IDEAL fat-water separation.

    Science.gov (United States)

    Kijowski, Richard; Tuite, Michael; Passov, Leo; Shimakawa, Ann; Yu, Huanzhou; Hu, Huanzhou; Reeder, Scott B

    2008-07-01

    To demonstrate the feasibility of evaluating the articular cartilage of the knee joint at 3.0T using gradient refocused acquisition in the steady-state (GRASS) and iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) fat-water separation. Bloch equation simulations and a clinical pilot study (n = 10 knees) were performed to determine the influence of flip angle of the IDEAL-GRASS sequence on the signal-to-noise ratio (SNR) of cartilage and synovial fluid and the contrast-to-noise ratio (CNR) between cartilage and synovial fluid at 3.0T. The optimized IDEAL-GRASS sequence was then performed on 30 symptomatic patients as part of the routine 3.0T knee MRI examination at our institution. The optimal flip angle was 50 degrees for IDEAL-GRASS cartilage imaging, which maximized contrast between cartilage and synovial fluid. The IDEAL-GRASS sequence consistently produced high-quality fat- and water-separated images of the knee with bright synovial fluid and 0.39 x 0.67 x 1.0 mm resolution in 5 minutes. IDEAL-GRASS images had high cartilage SNR and high contrast between cartilage and adjacent joint structures. The IDEAL-GRASS sequence provided excellent visualization of cartilage lesions in all patients. The IDEAL-GRASS sequence shows promise for use as a morphologic cartilage imaging sequence at 3.0T. (c) 2008 Wiley-Liss, Inc.

  14. Chicken meat quality as a function of fasting period and water spray

    Directory of Open Access Journals (Sweden)

    CM Komiyama

    2008-09-01

    Full Text Available This study aimed at evaluating the effect of different fasting periods and water spray during lairage on the quality of chicken meat. A number of 300 male Ross broilers were reared up to 42 days of age, and submitted to four pre-slaughter fasting periods (4, 8, 12, and 16 hours and sprayed with water or not during lairage. Deboned breast meat was submitted to the following analysis: pH, color, drip loss, water retention capacity, cooking loss, and shear force. There was a significant effect (p < 0.05 of fasting period on meat luminosity was significantly different, with the highest value obtained for 4-hour fasting, whereas no difference was found among the other fasting periods. Meat pH values were different among fasting periods when birds received water spray, with birds fasted for 4, 8, and 12 hours of fasting presenting lower meat pH values (5.87, 5.87, and 6.04, respectively. The interaction between fasting period and water spray influenced meat drip loss and cooking loss, with birds fasted for 16h and not receiving water spray presenting higher drip loss (4.88 and higher cooking loss (28.24 as compared to the other birds. Fasting period affects meat quality, and very short periods (4h impair meat quality.

  15. Modifications to the steady-state 41-node thermoregulatory model including validation of the respiratory and diffusional water loss equations

    Science.gov (United States)

    1974-01-01

    After the simplified version of the 41-Node Stolwijk Metabolic Man Model was implemented on the Sigma 3 and UNIVAC 1110 computers in batch mode, it became desirable to make certain revisions. First, the availability of time-sharing terminals makes it possible to provide the capability and flexibility of conversational interaction between user and model. Secondly, recent physiological studies show the need to revise certain parameter values contained in the model. Thirdly, it was desired to make quantitative and accurate predictions of evaporative water loss for humans in an orbiting space station. The result of the first phase of this effort are reported.

  16. Effect of Periodic Water Addition on Citric Acid Production in Solid State Fermentation

    Science.gov (United States)

    Utpat, Shraddha S.; Kinnige, Pallavi T.; Dhamole, Pradip B.

    2013-09-01

    Water addition is one of the methods used to control the moisture loss in solid state fermentation (SSF). However, none of the studies report the timing of water addition and amount of water to be added in SSF. Therefore, this work was undertaken with an objective to evaluate the performance of periodic water addition on citric acid production in SSF. Experiments were conducted at different moistures (50-80 %) and temperatures (30-40 °C) to simulate the conditions in a fermenter. Citric acid production by Aspergillus niger (ATCC 9029) using sugarcane baggase was chosen as a model system. Based on the moisture profile, citric acid and sugar data, a strategy was designed for periodic addition of water. Water addition at 48, 96, 144 and 192 h enhanced the citric acid production by 62 % whereas water addition at 72, 120, and 168 h increased the citric acid production by just 17 %.

  17. Covariation of coastal water temperature and microbial pollution at interannual to tidal periods

    Science.gov (United States)

    Boehm, Alexandria B.; Lluch-Cota, Daniel B.; Davis, Kristen A.; Winant, Clinton D.; Monismith, Stephen G.

    2004-03-01

    Water temperature and fecal indicator bacteria levels covary along the shoreline of Huntington and Newport Beach, California at interannual to tidal periods. During summer, cooler than average waters caused by interannual variability in sea surface temperature (SST), synoptic upwelling, and tidal-period cooling are coincident with elevated levels of microbial pollution in the surf zone. This relationship can be explained by the effects of weakening in stratification on the fate of a waste water plume and the prolonged persistence of fecal indicator bacteria in colder waters. During winter, warmer than average water caused by basin scale oscillations and atmospheric and oceanographic processes that contribute to the Multivariate El Nino Southern Oscillation Index are indicative of elevated total coliform levels in the surf zone. The elevated coliform levels can be ascribed to increased rainfall, and the resultant storm water inflow to the surf zone.

  18. Hydrogeology and steady-state numerical simulation of groundwater flow in the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado

    Science.gov (United States)

    Arnold, L.R.

    2010-01-01

    The Lost Creek Designated Ground Water Basin (Lost Creek basin) is an important alluvial aquifer for irrigation, public supply, and domestic water uses in northeastern Colorado. Beginning in 2005, the U.S. Geological Survey, in cooperation with the Lost Creek Ground Water Management District and the Colorado Water Conservation Board, collected hydrologic data and constructed a steady-state numerical groundwater flow model of the Lost Creek basin. The model builds upon the work of previous investigators to provide an updated tool for simulating the potential effects of various hydrologic stresses on groundwater flow and evaluating possible aquifer-management strategies. As part of model development, the thickness and extent of regolith sediments in the basin were mapped, and data were collected concerning aquifer recharge beneath native grassland, nonirrigated agricultural fields, irrigated agricultural fields, and ephemeral stream channels. The thickness and extent of regolith in the Lost Creek basin indicate the presence of a 2- to 7-mile-wide buried paleovalley that extends along the Lost Creek basin from south to north, where it joins the alluvial valley of the South Platte River valley. Regolith that fills the paleovalley is as much as about 190 ft thick. Average annual recharge from infiltration of precipitation on native grassland and nonirrigated agricultural fields was estimated by using the chloride mass-balance method to range from 0.1 to 0.6 inch, which represents about 1-4 percent of long-term average precipitation. Average annual recharge from infiltration of ephemeral streamflow was estimated by using apparent downward velocities of chloride peaks to range from 5.7 to 8.2 inches. Average annual recharge beneath irrigated agricultural fields was estimated by using passive-wick lysimeters and a water-balance approach to range from 0 to 11.3 inches, depending on irrigation method, soil type, crop type, and the net quantity of irrigation water applied

  19. Chicken meat quality as a function of fasting period and water spray

    OpenAIRE

    CM Komiyama; AA Mendes; SE Takahashi; Moreira, J.; RG Garcia; Sanfelice,C; HS Borba; FR Leonel; ICL Almeida Paz; Balog, A.

    2008-01-01

    This study aimed at evaluating the effect of different fasting periods and water spray during lairage on the quality of chicken meat. A number of 300 male Ross broilers were reared up to 42 days of age, and submitted to four pre-slaughter fasting periods (4, 8, 12, and 16 hours) and sprayed with water or not during lairage. Deboned breast meat was submitted to the following analysis: pH, color, drip loss, water retention capacity, cooking loss, and shear force. There was a significant effect ...

  20. Simulated carbon and water processes of forest ecosystems in Forsmark and Oskarshamn during a 100-year period

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, David; Jansson, Per-Erik [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Land and Water Resources Engineering; Gaerdenaes, Annemieke [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences; Eckersten, Henrik [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Crop Production Ecology

    2006-12-15

    The Swedish Nuclear Fuel and Waste Management Co (SKB) is currently investigating the Forsmark and Oskarshamn areas for possible localisation of a repository for spent nuclear fuel. Important components of the investigations are characterizations of the land surface ecosystems in the areas with respect to hydrological and biological processes, and their implications for the fate of radionuclide contaminants entering the biosphere from a shallow groundwater contamination. In this study, we simulate water balance and carbon turnover processes in forest ecosystems representative for the Forsmark and Oskarshamn areas for a 100-year period using the ecosystem process model CoupModel. The CoupModel describes the fluxes of water and matter in a one-dimensional soil-vegetation-atmosphere system, forced by time series of meteorological variables. The model has previously been parameterized for many of the vegetation systems that can be found in the Forsmark and Oskarshamn areas: spruce/pine forests, willow, grassland and different agricultural crops. This report presents a platform for further use of models like CoupModel for investigations of radionuclide turnover in the Forsmark and Oskarshamn area based on SKB data, including a data set of meteorological forcing variables for Forsmark 1970-2004, suitable for simulations of a 100-year period representing the present day climate, a hydrological parameterization of the CoupModel for simulations of the forest ecosystems in the Forsmark and Oskarshamn areas, and simulated carbon budgets and process descriptions for Forsmark that correspond to a possible steady state of the soil storage of the forest ecosystem.

  1. Sodium periodate as a primary oxidant for water-oxidation catalysts.

    Science.gov (United States)

    Parent, Alexander R; Brewster, Timothy P; De Wolf, Wendy; Crabtree, Robert H; Brudvig, Gary W

    2012-06-04

    Sodium periodate was characterized as a primary chemical oxidant for the catalytic evolution of oxygen at neutral pH using a variety of water-oxidation catalysts. The visible spectra of solutions formed from Cp*Ir(bpy)SO(4) during oxygen-evolution catalysis were measured. NMR spectroscopy suggests that the catalyst remains molecular after several turnovers with sodium periodate. Two of our [Cp*Ir(bis-NHC)][PF(6)](2) complexes, along with other literature catalysts, such as the manganese terpyridyl dimer, Hill's cobalt polyoxometallate, and Meyer's blue dimer, were also tested for activity. Sodium periodate was found to function only for water-oxidation catalysts with low overpotentials. This specificity is attributed to the relatively low oxidizing capability of sodium periodate solutions relative to solutions of other common primary oxidants. Studying oxygen-evolution catalysis by using sodium periodate as a primary oxidant may, therefore, provide preliminary evidence that a given catalyst has a low overpotential.

  2. WATER ACTIVITY INFLUENCE ON THE SAFE AGING PERIOD OF CONDENSED MILK

    Directory of Open Access Journals (Sweden)

    Ilona Šostakienė

    2010-01-01

    Full Text Available The majority of chemical and biological processes causing the change of nutrients and finally their spoilage are dependent on water. Microbiological growth is directly related to water activity. Water activity (aw was introduced by an Australian microbiologist W.J. Scott in 1952. He defined this concept as a “fundamental property of water solutions” and i.e. a ratio between pure water (p0 and steam pressure solution (p. The water activity of the unsweetened condensed milk packed into canister remains unchanged during the storage period (aw.= 0,902. The water activity in the sweetened condensed milk slightly increases after 18 months (aw.= 0,784, after 18 months aw = 0,787. Though water activity does not actually change the storage of such a product and does not create a possibility for the growth of microorganisms. However, milk is a system of array compounds and a limitless storage of such a product is impossible. It is determined that the allowed storage period of 12 months is justified as after this period a major part of milk changes become accelerated

  3. Comparisons of Water Quality and Biological Variables from Colorado River Shoreline Habitats in Grand Canyon, Arizona, under Steady and Fluctuating Discharges from Glen Canyon Dam

    Science.gov (United States)

    Ralston, Barbara E.; Lauretta, Matthew V.; Kennedy, Theodore A.

    2007-01-01

    Glen Canyon Dam operations are known to affect mainstem Colorado River temperature and shoreline habitats for native fish. Options for ameliorating the impacts that operations have on young native fish include changing release volumes and/or changing the daily range of releases. Long-term alterations of operations that may produce a measurable biological response can be costly, particularly if the treatment involves reduced power generation. In September and October 2005, a series of two-week releases occurred that alternated between daily fluctuations that varied by 76 m3 s-1 and steady releases. The purpose of these short-term experiments was to study the effect of daily operations on water quality parameters and biotic constituents (phytoplankton, macroinvertebrates, and fishes) of associated shoreline habitats. Our results indicate that measured biological and physical parameters were, in general, unaffected by flow treatments. However, results should be interpreted cautiously as time within and between treatments was likely insufficient to affect measured parameters. These results lead to the recommendation that studies like this may be more amenable to laboratory experiments first and then applied to a large-scale setting, preferably for longer duration.

  4. Depth of soil water uptake by tropical rainforest trees during dry periods: does tree dimension matter?

    Science.gov (United States)

    Stahl, Clément; Hérault, Bruno; Rossi, Vivien; Burban, Benoit; Bréchet, Claude; Bonal, Damien

    2013-12-01

    Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψpd) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψpd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models.

  5. An Iterated Local Search Algorithm for Multi-Period Water Distribution Network Design Optimization

    Directory of Open Access Journals (Sweden)

    Annelies De Corte

    2016-08-01

    Full Text Available Water distribution networks consist of different components, such as reservoirs and pipes, and exist to provide users (households, agriculture, industry with high-quality water at adequate pressure and flow. Water distribution network design optimization aims to find optimal diameters for every pipe, chosen from a limited set of commercially available diameters. This combinatorial optimization problem has received a lot of attention over the past forty years. In this paper, the well-studied single-period problem is extended to a multi-period setting in which time varying demand patterns occur. Moreover, an additional constraint—which sets a maximum water velocity—is imposed. A metaheuristic technique called iterated local search is applied to tackle this challenging optimization problem. A full-factorial experiment is conducted to validate the added value of the algorithm components and to configure optimal parameter settings. The algorithm is tested on a broad range of 150 different (freely available test networks.

  6. Long-period variability of oxygen dissolved in Black Sea waters

    Science.gov (United States)

    Polonsky, A. B.; Kotolypova, A. A.

    2017-09-01

    Using an archival database from the Institute of Natural and Technical Systems, the low-frequency variability of oxygen dissolved in the deep-water and northwestern parts of the Black Sea for the period of 1955-2004 is analyzed. The upper mixed layer (UML) is characterized by quasi-periodic variability in the dissolved oxygen concentration in the interdecadal scale. Deeper, a long-term decrease in the oxygen concentration is recorded.

  7. Diurnal variations in water relations of deficit irrigated lemon trees during fruit growth period

    Directory of Open Access Journals (Sweden)

    Y. García-Orellana

    2013-01-01

    Full Text Available Field-grown lemon trees (Citrus limon (L. Burm. fil. cv. Fino were subjected to different drip irrigation treatments: a control treatment, irrigated daily above crop water requirements in order to obtain non-limiting soil water conditions and two deficit irrigation treatments, reducing the water applied according to the maximum daily trunk shrinkage (MDS signal intensity (actual MDS/control treatment MDS threshold values of 1.25 (T1 treatment and 1.35 (T2 treatment, which induced two different drought stress levels. Daily variations in leaf (Yleaf and stem (Ystem water potentials, leaf conductance, net photosynthesis, sap flow (SF and trunk diameter fluctuations were studied on four occasions during the lemon fruit growth period. Ystem and Yleaf revealed a diurnal pattern in response to changes in evaporative demand of the atmosphere. Both water potentials decreased in response to water deficits, which were more pronounced in the T2 treatment. Ystem was seen to be a better plant water status indicator than Yleaf. The difference between the two values of Y (Ystem - Yleaf  = DY was closely correlated with sap flow, making it a suitable measure of leaf transpiration. Using the slope of this relationship, the canopy hydraulic conductance (KC was estimated. When other continuously recorded plant-based indicators are not accessible, the concurrent measurement of leaf and stem water potentials at midday, which are relatively inexpensive to measure and user-friendly, act as sufficiently good indicators of the plant water status in field grown Fino lemon trees.

  8. A randomized, 2-period, crossover design study to assess the effects of dexlansoprazole, lansoprazole, esomeprazole, and omeprazole on the steady-state pharmacokinetics and pharmacodynamics of clopidogrel in healthy volunteers.

    Science.gov (United States)

    Frelinger, Andrew L; Lee, Ronald D; Mulford, Darcy J; Wu, Jingtao; Nudurupati, Sai; Nigam, Anu; Brooks, Julie K; Bhatt, Deepak L; Michelson, Alan D

    2012-04-03

    The aim of this study was to assess the effects of different proton pump inhibitors (PPIs) on the steady-state pharmacokinetics and pharmacodynamics of clopidogrel. Metabolism of clopidogrel requires cytochrome P450s (CYPs), including CYP2C19. However, PPIs may inhibit CYP2C19, potentially reducing the effectiveness of clopidogrel. A randomized, open-label, 2-period, crossover study of healthy subjects (n = 160, age 18 to 55 years, homozygous for CYP2C19 extensive metabolizer genotype, confined, standardized diet) was conducted. Clopidogrel 75 mg with or without a PPI (dexlansoprazole 60 mg, lansoprazole 30 mg, esomeprazole 40 mg, or, as a positive control to maximize potential interaction and demonstrate assay sensitivity, omeprazole 80 mg) was given daily for 9 days. Pharmacokinetics and pharmacodynamics were assessed on days 9 and 10. Pharmacodynamic end-points were vasodilator-stimulated phosphoprotein P2Y(12) platelet reactivity index, maximal platelet aggregation to 5 and 20 μmol/l adenosine diphosphate, and VerifyNow P2Y12 platelet response units. Pharmacokinetic and pharmacodynamic responses with omeprazole demonstrated assay sensitivity. The area under the curve for clopidogrel active metabolite decreased significantly with esomeprazole but not with dexlansoprazole or lansoprazole. Similarly, esomeprazole but not dexlansoprazole or lansoprazole significantly reduced the effect of clopidogrel on vasodilator-stimulated phosphoprotein platelet reactivity index. All PPIs decreased the peak plasma concentration of clopidogrel active metabolite (omeprazole > esomeprazole > lansoprazole > dexlansoprazole) and showed a corresponding order of potency for effects on maximal platelet aggregation and platelet response units. Generation of clopidogrel active metabolite and inhibition of platelet function were reduced less by the coadministration of dexlansoprazole or lansoprazole with clopidogrel than by the coadministration of esomeprazole or omeprazole. These

  9. Alleviation of Water Stress Effects on MR220 Rice by Application of Periodical Water Stress and Potassium Fertilization

    Directory of Open Access Journals (Sweden)

    Nurul Amalina Mohd Zain

    2014-02-01

    Full Text Available The use of periodical water stress and potassium fertilization may enhance rice tolerance to drought stress and improve the crop’s instantaneous water use efficiency without much yield reduction. This study was conducted to assess the effects of different periodical water stress combined with potassium fertilization regimes on growth, yield, leaf gas exchanges and biochemical changes in rice grown in pots and compare them with standard local rice grower practices. Five treatments including (1 standard local grower’s practice (control, 80CF = 80 kg K2O/ha + control flooding; (2 120PW15 = 120 kg K2O/ha + periodical water stress for 15 days; (3 120DS15V = 120 kg K2O/ha + drought stress for 15 days during the vegetative stage; (4 120DS25V = 120 kg K2O/ha + drought stress for 25 days and (5 120DS15R = 120 kg K2O/ha + drought stress for 15 days during the reproductive stage, were evaluated in this experiment. Control and 120PW15 treatments were stopped at 100 DAS, and continuously saturated conditions were applied until harvest. It was found that rice under 120PW15 treatment showed tolerance to drought stress evidenced by increased water use efficiency, peroxidase (POX, catalase (CAT and proline levels, maximum efficiency of photosystem II (fv/fm and lower minimal fluorescence (fo, compared to other treatments. Path coefficient analysis revealed that most of parameters contribute directly rather than indirectly to rice yield. In this experiment, there were four factors that are directly involved with rice yield: grain soluble sugar, photosynthesis, water use efficiency and total chlorophyll content. The residual factors affecting rice yield are observed to be quite low in the experiment (0.350, confirming that rice yield was mostly influenced by the parameters measured during the study.

  10. "Periodic-table-style" paper device for monitoring heavy metals in water.

    Science.gov (United States)

    Li, Miaosi; Cao, Rong; Nilghaz, Azadeh; Guan, Liyun; Zhang, Xiwang; Shen, Wei

    2015-03-03

    If a paper-based analytical device (μ-PAD) could be made by printing indicators for detection of heavy metals in chemical symbols of the metals in a style of the periodic table of elements, it could be possible for such μ-PAD to report the presence and the safety level of heavy metal ions in water simultaneously and by text message. This device would be able to provide easy solutions to field-based monitoring of heavy metals in industrial wastewater discharges and in irrigating and drinking water. Text-reporting could promptly inform even nonprofessional users of the water quality. This work presents a proof of concept study of this idea. Cu(II), Ni(II), and Cr(VI) were chosen to demonstrate the feasibility, specificity, and reliability of paper-based text-reporting devices for monitoring heavy metals in water.

  11. Water resources change in Russia, Ukraine and Belarus in the post-soviet period

    Science.gov (United States)

    Bibikova, Tatiana

    2010-05-01

    In recent decades large changes in the state, formation and utilization of water resources have taken place on the territory of the former Soviet Union. There are several reasons for this. Water resources change is caused by different natural and anthropogenic factors. The main reason is climatic, first of all warming during cold seasons and augmentation of rainfall in winter and in summer. During the last 15 years on the territories of Russia and Belarus the rise in river runoff has been observed. Changes in the river runoff in Ukraine were not so certain in the ninetieth but at the very end of the 20th century the raise was also seen. Change of the climatic conditions coincides with the human impact on water resources. After the collapse of the Soviet Union there were great changes in political, social and economic spheres of the new formed states. The economic recession as well as the economic rise since the last years of the 20th century has affected the state of water resources. During the last 15 years water use and therefore water sewage reduction has been well seen. The structure of water consumption and therefore of all water management is defined by climatic conditions. First of all it is seen in irrigated agriculture, but also takes place in other branches of water management. We tried to show the dependence of some water consumption characteristics on the mean annual air temperature and on its correlation with the annual precipitation in the regions of the Russian Federation, Ukraine and Belarus. It was found out that in the regions of Russia with low air temperature water consumption per area unit is less than on the territories with high air temperature. This is typical for the period of economic recession after the collapse of the USSR, as well as for the period of economic growth during the last years. Besides, more severe climate in Russia causes lower water consumption per area unit, at the same time in Russia self-purification is less intensive

  12. Development of Extended Period Pressure-Dependent Demand Water Distribution Models

    Energy Technology Data Exchange (ETDEWEB)

    Judi, David R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mcpherson, Timothy N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-20

    Los Alamos National Laboratory (LANL) has used modeling and simulation of water distribution systems for N-1 contingency analyses to assess criticality of water system assets. Critical components considered in these analyses include pumps, tanks, and supply sources, in addition to critical pipes or aqueducts. A contingency represents the complete removal of the asset from system operation. For each contingency, an extended period simulation (EPS) is run using EPANET. An EPS simulates water system behavior over a time period, typically at least 24 hours. It assesses the ability of a system to respond and recover from asset disruption through distributed storage in tanks throughout the system. Contingencies of concern are identified as those in which some portion of the water system has unmet delivery requirements. A delivery requirement is defined as an aggregation of water demands within a service area, similar to an electric power demand. The metric used to identify areas of unmet delivery requirement in these studies is a pressure threshold of 15 pounds per square inch (psi). This pressure threshold is used because it is below the required pressure for fire protection. Any location in the model with pressure that drops below this threshold at any time during an EPS is considered to have unmet service requirements and is used to determine cascading consequences. The outage area for a contingency is the aggregation of all service areas with a pressure below the threshold at any time during the EPS.

  13. Van der Waals forces from first principles for periodic systems: Application to graphene-water interactions

    OpenAIRE

    Partovi-Azar, Pouya; Kühne, T. D.

    2015-01-01

    We extend the method of Silvestrelli [P. L. Silvestrelli, J. Chem. Phys. 139, 054106 (2013)] to approximate long-range van der Waals interactions at the density functional theory level based on maximally localized Wannier functions combined with the quantum harmonic oscillator model, to periodic systems. Applying this scheme to study London dispersion forces between graphene and water layers, we demonstrate that collective many-body effects beyond simple additive pair-wise interactions are es...

  14. Computer forecasting of the soil water infiltration parameters in seasonal freezing and thawing periods

    National Research Council Canada - National Science Library

    Fan, Guisheng; Han, Yonghong; Ma, Danni

    2013-01-01

    ..., most research on soil moisture infiltration during freezing and thawing periods have been focused on the water loss and soil erosion caused by snow melting  [1–3] , the soil swelling from soil frozen-in and the change of moisture and salinity  [4] , the influence factors and mechanism of moisture infiltration into freezing and thawing soils  [5–9] and...

  15. Diurnal variations in water relations of deficit irrigated lemon trees during fruit growth period

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Orellana, Y.; Ortuno, M. F.; Conejero, W.; Ruiz-Sanchez, M. C.

    2013-05-01

    Field-grown lemon trees (Citrus limon (L.) Burm. fil. cv. Fino) were subjected to different drip irrigation treatments: a control treatment, irrigated daily above crop water requirements in order to obtain non-limiting soil water conditions and two deficit irrigation treatments, reducing the water applied according to the maximum daily trunk shrinkage (MDS) signal intensity (actual MDS/control treatment MDS) threshold values of 1.25 (T1 treatment) and 1.35 (T2 treatment), which induced two different drought stress levels. Daily variations in leaf (Y{sub l}eaf) and stem (Y{sub s}tem) water potentials, leaf conductance, net photosynthesis, sap flow (SF) and trunk diameter fluctuations were studied on four occasions during the lemon fruit growth period. Ystem and Y{sub l}eaf revealed a diurnal pattern in response to changes in evaporative demand of the atmosphere. Both water potentials decreased in response to water deficits, which were more pronounced in the T2 treatment. Y{sub s}tem was seen to be a better plant water status indicator than Y{sub l}eaf. The difference between the two values of Y (Y{sub s}tem - Y{sub l}eaf {Delta}{Psi}) was closely correlated with sap flow, making it a suitable measure of leaf transpiration. Using the slope of this relationship, the canopy hydraulic conductance (KC) was estimated. When other continuously recorded plant-based indicators are not accessible, the concurrent measurement of leaf and stem water potentials at midday, which are relatively inexpensive to measure and user-friendly, act as sufficiently good indicators of the plant water status in field grown Fino lemon trees. (Author) 40 refs.

  16. Ground water quality evaluation in the lean period of a mining township

    Science.gov (United States)

    Prasad, Bably; Maiti, Deblina; Kumar, Adarsh

    2017-11-01

    Groundwater of mining towns is very much affected due to mining activity. During mining of mineral from underground, huge quantity of ground water is pumped out to make mining possible. Groundwater samples have been collected from the 20 sampling sites of Dhanbad, a mining Township, in the lean period (summer) of the years 2011 and 2014. Four samples have been obtained from open well and 16 from hand pumps. Water quality parameters such as pH, total hardness, Ca hardness, Mg Hardness, chloride, sulphate, total dissolved solids, and heavy metals have been evaluated. The values of pH, total hardness, Ca hardness, Mg hardness, chloride, sulphate, and total dissolved solids have increased in 2014 as compared to 2011 which may be due to increase in mineral content in the lean period and decrease in the rate of recharge of aquifers in 2014. The concentration of heavy metals has decreased in 2014 as compared to 2011 which may be due to less leaching of heavy metals from the ground strata. From the overall study, it has been concluded that most of the water quality parameters of all the 20 groundwater samples in the year 2014 are not exceeding the acceptable concentration level, as mentioned in Indian drinking water specifications. Groundwater in the year 2014 has not shown any significant change in its quality as compared to the year 2011. In the incoming years, quality of groundwater will not show any drastic change unless and until any anthropogenic activity other than mining will affect it.

  17. Heterogeneous Catalysis for Water Oxidation by an Iridium Complex Immobilized on Bipyridine-Periodic Mesoporous Organosilica.

    Science.gov (United States)

    Liu, Xiao; Maegawa, Yoshifumi; Goto, Yasutomo; Hara, Kenji; Inagaki, Shinji

    2016-07-04

    Heterogenization of metal-complex catalysts for water oxidation without loss of their catalytic activity is important for the development of devices simulating photosynthesis. In this study, efficient heterogeneous iridium complexes for water oxidation were prepared using bipyridine-bridged periodic mesoporous organosilica (BPy-PMO) as a solid chelating ligand. The BPy-PMO-based iridium catalysts (Ir-BPy-PMO) were prepared by postsynthetic metalation of BPy-PMO and characterized through physicochemical analyses. The Ir-BPy-PMOs showed high catalytic activity for water oxidation. The turnover frequency (TOF) values for Ir-BPy-PMOs were one order of magnitude higher than those of conventional heterogeneous iridium catalysts. The reusability and stability of Ir-BPy-PMO were also examined, and detailed characterization was conducted using powder X-ray diffraction, nitrogen adsorption, (13) C DD MAS NMR spectroscopy, TEM, and XAFS methods. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Properties of Water Confined in Periodic Mesoporous Organosilicas: Nanoimprinting the Local Structure.

    Science.gov (United States)

    Mietner, J Benedikt; Brieler, Felix J; Lee, Young Joo; Fröba, Michael

    2017-09-25

    The properties of materials confined in porous media are important in scientific and technological aspects. Topology, size, and surface polarity of the pores play a critical role in the confinement effects, however, knowledge regarding the guest-pore interface structure is still lacking. Herein, we show that the molecular mobility of water confined in periodic mesoporous organosilicas (PMOs) is influenced by the polarity of the organic moiety. Multidimensional solid-state NMR spectroscopy directly probes the spatial arrangement of water inside the pores, showing that water interacts either with only the silicate layer or with both silicate and organic layers depending on the alternating surface polarity. A modulated and a uniform pore filling mode are proposed for different types of PMOs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. North Atlantic Surface and Deep-Water Hydrography during the Early Pliocene Warm Period

    Science.gov (United States)

    Voelker, A. H. L.; Evans, H. F.; Naafs, B. D.; Cavaleiro, C. D.; Rebotim, A.; Ventura, C.; Stein, R. H.; Channell, J. E. T.

    2014-12-01

    The early Pliocene, with atmospheric carbon dioxide concentrations at levels similar to today, is seen as a case study for Earth's future climate evolution. During this period the progressive closing of the Central American Seaway led to increased poleward heat and salt transport within the Atlantic with North Atlantic Deep Water (NADW) becoming warmer and saltier and resulting in an enhanced Atlantic Meridional Overturning Circulation (AMOC). In order to understand how stable the AMOC really was we produced millennial-scale (1-2 kyr) surface and deep-water records for IODP Site U1313 (41°N, 33°W, 3412m) for the interval from 3.4 to 4.1 Ma. This site is ideally located to monitor past AMOC changes with North Atlantic Drift waters at the surface and NADW in the deep. Although interglacial/glacial cycles are visible, the higher frequency oscillations recorded in both the planktonic G. ruber (white) and benthic Cibicidoides sp. δ18O records impede tuning to the LR04 stack (Lisiecki and Raymo, 2005). We therefore exploit a different approach: using the magnetic polarity chrons (Gilbert, Cochiti) as recorded at Site U1313 as framework, we tune our benthic δ18O record to that of ODP Site 1085 (on LR04 ages). The benthic δ13C record shows millennial-scale oscillations, and the values indicate nearly continuous NADW presence and confirm a strong AMOC, also during most of the glacial periods. Varying surface water conditions, especially during the younger interglacial periods, are reflected in the G. ruber isotope data and appear to be linked to salinity changes since they are not recorded in the alkenone sea-surface temperature data. Although glacial stages Gi 2 and Gi 4 show the expected higher benthic δ18O values, Gi 6 was the glacial period with the strongest impact on the AMOC as revealed by cooler, less ventilated surface waters and a less ventilated NADW. Overall, the AMOC was strong throughout, but experienced high frequency oscillations at a level similar to

  20. Evaluation of the return periods of water crises and evaporation in Monte Cotugno reservoir (Southern Italy)

    Science.gov (United States)

    Copertino, Vito; Lo Vecchio, Giuseppina; Marotta, Lucia; Pastore, Vittoria; Ponzio, Giuseppe; Scavone, Giuseppina; Telesca, Vito; Vita, Michele

    2010-05-01

    In the past water resources management has been dealt and solved increasing water availabilities; today such opportunities have been considerably reduced and the technical-scientific perspectives are addressed above all to improve water system effectiveness and to promote an use of water resources that holds account of the droughts frequency and based on a correct estimate of the hydrologic balance. In this work a study on the water stored in Monte Cotugno reservoir in Sinni river - Basilicata (Southern Italy) - is proposed, estimating water crises return periods and reservoir evaporation. For such purpose the runs method was applied, based on the comparison between the temporal series of the "water volume" hydrological variable and a threshold representative of the "normal" conditions regarding which the availability in excess or defect was estimated. This allowed to individualize the beginning and the end of a water crisis event and to characterize the droughts in terms of duration, sum deficit and intensity. Therefore the return period was evaluated by means of the methodology proposed by Shiau and Shen in 2001, turned out equal approximately to 6 years. Such value was then verified with a frequency analysis of the "water volume" random variable, using the Weibull's distribution. Subsequently, the Fourier's analysis in the last twenty years was carried out, obtaining the same result of the previous methods. Moreover, in proximity of the Monte Cotugno reservoir the weather station of Senise is located, managed by ALSIA (Agenzia Lucana di Sviluppo e Innovazione in Agricultura), that provides in continuous measurements of air temperature and humidity, wind speed and direction, and global solar radiation since 2000. Such parameters allowed to apply five methods for reservoir evaporation estimate selected from those proposed in the literature, of which the first three, the Jensen-Haise's method, Makkink's method and Stephens-Stewart's one are based on solar radiation

  1. Progressive development of water resources in the Middle East for sustainable water supply in a period of climate change.

    Science.gov (United States)

    Issar, Arie S; Adar, Eilon

    2010-11-28

    The history of the Middle East has been influenced by past global climatic changes. Warm periods caused droughts, resulting in desertification, migration and war. Cold periods were humid and brought prosperity and agricultural settlement to the desert fringes. The forecast based on this correlation is that the present global warming will cause the drying up of the Middle East. As in the past, this negative impact should be mitigated by using the groundwater resources stored from past wetter times. This will involve deep drilling, pumping and modern irrigation methods within the framework of a new policy of 'progressive development', which will entail the use of currently undeveloped natural water resources beyond that of present water replenishment. While the use of the one-time groundwater reserves is taking place, a master long-term comprehensive progressive development plan for the Middle East will be prepared. This plan will include the step-by-step development of other water resources such as treated effluents, desalinated brackish groundwater and desalination of seawater.

  2. Comparing the Performance of Artificial Intelligence Models in Estimating Water Quality Parameters in Periods of Low and High Water Flow

    Directory of Open Access Journals (Sweden)

    majid montaseri

    2017-03-01

    Full Text Available Introduction: A total dissolved solid (TDS is an important indicator for water quality assesment. Since the composition of mineral salts and discharge affects the TDS of water, it is important to understand the relationships of mineral salts composition with TDS. Materials and Methods: In this study, methods of artificial neural networks with five different training algorithm,Levenberg-Marquardt (LM, Scaled Conjugate Gradient (SCG, Fletcher Conjugate Gradient (CGF, One Step Secant (OSS and Gradient descent with adaptive learning rate backpropagation(GDAalgorithm and adaptive Neurofuzzy inference system based on Subtractive Clustering were used to model water quality properties of Zarrineh River Basin, to be developed in total dissolved solids prediction. ANN and ANFIS program code were written in MATLAB language. Here, the ANN with one hidden layer was used and the hidden nodes’ number was determined using trial and error. Different activation functions (logarithm sigmoid, tangent sigmoid and linear were tried for the hidden and output nodes. Therefore, water quality data from seven hydrometer stationswere used during the statistical period of 18years (1993-2010.In this research, the study period was divided into two periods of dry and wet flow, and then in a preliminary statistical analysis, the main parameters affecting the estimation of the TDS are determined and isused for modeling. 75% of data are used for remaining and 25% of the data are used for evaluation of the model, randomly. In this paper, three statistical evaluation criteria, correlation coefficient (R, the root mean square error (RMSE and mean absolute error (MAE were used to assess models’ performances. Results and Discussion: By applying correlation coefficients method between the parameters of water quality and discharge with total dissolved solid in two periods, wet and dry periods, the significant (at 95% level variables entered into the model were Q, HCO3., Cl, So4, Ca

  3. Born dry in the photoevaporation desert: Kepler's ultra-short-period planets formed water-poor

    Science.gov (United States)

    Lopez, Eric D.

    2017-11-01

    Recent surveys have uncovered an exciting new population of ultra-short-period (USP) planets with orbital periods less than a day. These planets typically have radii ≲1.5 R⊕, indicating that they likely have rocky compositions. This stands in contrast to the overall distribution of planets out to ˜100 d, which is dominated by low-density sub-Neptunes above 2 R⊕, which must have gaseous envelopes to explain their size. However, on the USP orbits, planets are bombarded by intense levels of photoionizing radiation and consequently gaseous sub-Neptunes are extremely vulnerable to losing their envelopes to atmospheric photoevaporation. Using models of planet evolution, I show that the rocky USP planets can easily be produced as the evaporated remnants of sub-Neptunes with H/He envelopes and that we can therefore understand the observed dearth of USP sub-Neptunes as a natural consequence of photoevaporation. Critically however, planets on USP orbits could often retain their envelopes if they are formed with very high-metallicity water-dominated envelopes. Such water-rich planets would commonly be ≳2 R⊕ today, which is inconsistent with the observed evaporation desert, indicating that most USP planets likely formed from water-poor material within the snow-line. Finally, I examine the special case of 55 Cancri e and its possible composition in the light of recent observations, and discuss the prospects for further characterizing this population with future observations.

  4. Quantum steady computation

    Energy Technology Data Exchange (ETDEWEB)

    Castagnoli, G. (Dipt. di Informatica, Sistemistica, Telematica, Univ. di Genova, Viale Causa 13, 16145 Genova (IT))

    1991-08-10

    This paper reports that current conceptions of quantum mechanical computers inherit from conventional digital machines two apparently interacting features, machine imperfection and temporal development of the computational process. On account of machine imperfection, the process would become ideally reversible only in the limiting case of zero speed. Therefore the process is irreversible in practice and cannot be considered to be a fundamental quantum one. By giving up classical features and using a linear, reversible and non-sequential representation of the computational process - not realizable in classical machines - the process can be identified with the mathematical form of a quantum steady state. This form of steady quantum computation would seem to have an important bearing on the notion of cognition.

  5. Water level changes for Lake Turkana and climate variability during the African Humid Period

    Science.gov (United States)

    Bloszies, C.; Forman, S. L.; Wright, D. K.

    2013-12-01

    The chronology of East African paleoclimate suggests the transition through the African Humid Period (AHP) at ca. 15 to 5 ka was a binary shift from wet conditions in the Late Pleistocene to current aridity. Previous studies indicate that water levels for Lake Turkana for the AHP were stable at ~88 to 98 m above current level with outflow into the White Nile Basin. This study of relict beaches around Lake Turkana indicates surprisingly >50 m variability in water level between 14 and 4 ka. The elevation of past water level is constrained by barometric and GPS-based altimetry of relict beaches and age control by 14C dating of associated mollusks and OSL dating of quartz grains from surrounding littoral and sublittoral deposits. We also include well provenanced lake level data from prior studies to constrain more fully the timing and height of water level fluctuations in the Late Quaternary. Additionally, previous studies indicate that peak water levels may be regionally amplified by increased precipitation causing overflow into the Lake Turkana Basin from the adjacent Suguta and Chew Bahir basins, particularly during high stands at ca. >8.5 ka and at 6.3 ka. Our analysis of the Lake Turkana strandplain reveals that water level may have varied by × 60 m, potentially reaching the outlet elevation at ca.11.3, 10.3, 9.0, 6.3 and 5.1 ka. There are other possible high stands at ca. 13.0, 8.4, 7.8 and 7.0 ka with limited elevational and age constraints; it is unknown if these lake stands reached the outlet elevation. Evidence from relict strand plains indicate that lake level was probably below 20 m since ca. 4.5 ka, though there were two noticeable high stands up to >12 to 18 m at ca. 830 years ago and lake levels. Inferences on the source of moisture to sustain these many high stands are based on the isotopic data on leaf wax (δDwax) from lakes Tanganika and Victoria and associated sea surface temperature (SST) records from the Indian and the Atlantic oceans. A brief

  6. Water mass transformation in the Greenland Sea during the period 1986-2016

    Science.gov (United States)

    Brakstad, Ailin; Våge, Kjetil; Håvik, Lisbeth; Moore, Kent

    2017-04-01

    The Greenland Sea is among the few regions of the global ocean where deep convection, forming dense intermediate and deep water masses, takes place during winter. This process replenishes the deep ocean with oxygen and is important for maintaining its thermohaline properties. Several studies have documented significant changes in the convective activity in the Greenland Sea during the past few decades. In particular, the convection has been limited to the upper 2000 m since the cessation of deep and bottom convection in the 1980s. By analyzing historical hydrographic measurements from ships, autonomous profiling floats, and instrumented seals for the period 1986 to 2016, we find that a new, less dense class of intermediate water started forming in the Greenland Sea gyre in winters 1993-94 and 1994-95. The preceding winters were characterized by shallow (< 300 m) convection that resulted from a combination of anomalously fresh near-surface layers that increased the stability of the upper part of the water column and weak atmospheric forcing. The subsequent deeper convection marked the beginning of a pronounced change in the hydrographic structure of the upper 2000 m in the Greenland Sea that is still ongoing. Sensitivity studies, using a one-dimensional mixed-layer model, suggest that the deeper convection was primarily a result of reduced water column stability due to higher near-surface salinities. Since it first started forming in winter 1993-94, this less dense class of intermediate water has been the main product of convection in the Greenland Sea, and its volume has expanded in line with generally increased depths of convection over the past 10-15 years.

  7. Hormonal and Hydroxycinnamic Acids Profiles in Banana Leaves in Response to Various Periods of Water Stress

    Directory of Open Access Journals (Sweden)

    Jalel Mahouachi

    2014-01-01

    Full Text Available The pattern of change in the endogenous levels of several plant hormones and hydroxycinnamic acids in addition to growth and photosynthetic performance was investigated in banana plants (Musa acuminata cv. “Grand Nain” subjected to various cycles of drought. Water stress was imposed by withholding irrigation for six periods with subsequent rehydration. Data showed an increase in abscisic acid (ABA and indole-3-acetic acid (IAA levels, a transient increase in salicylic acid (SA concentration, and no changes in jasmonic acid (JA after each period of drought. Moreover, the levels of ferulic (FA and cinnamic acids (CA were increased, and plant growth and leaf gas exchange parameters were decreased by drought conditions. Overall, data suggest an involvement of hormones and hydroxycinnamic acids in plant avoidance of tissue dehydration. The increase in IAA concentration might alleviate the senescence of survival leaves and maintained cell elongation, and the accumulation of FA and CA could play a key role as a mechanism of photoprotection through leaf folding, contributing to the effect of ABA on inducing stomatal closure. Data also suggest that the role of SA similarly to JA might be limited to a transient and rapid increase at the onset of the first period of stress.

  8. Hormonal and hydroxycinnamic acids profiles in banana leaves in response to various periods of water stress.

    Science.gov (United States)

    Mahouachi, Jalel; López-Climent, María F; Gómez-Cadenas, Aurelio

    2014-01-01

    The pattern of change in the endogenous levels of several plant hormones and hydroxycinnamic acids in addition to growth and photosynthetic performance was investigated in banana plants (Musa acuminata cv. "Grand Nain") subjected to various cycles of drought. Water stress was imposed by withholding irrigation for six periods with subsequent rehydration. Data showed an increase in abscisic acid (ABA) and indole-3-acetic acid (IAA) levels, a transient increase in salicylic acid (SA) concentration, and no changes in jasmonic acid (JA) after each period of drought. Moreover, the levels of ferulic (FA) and cinnamic acids (CA) were increased, and plant growth and leaf gas exchange parameters were decreased by drought conditions. Overall, data suggest an involvement of hormones and hydroxycinnamic acids in plant avoidance of tissue dehydration. The increase in IAA concentration might alleviate the senescence of survival leaves and maintained cell elongation, and the accumulation of FA and CA could play a key role as a mechanism of photoprotection through leaf folding, contributing to the effect of ABA on inducing stomatal closure. Data also suggest that the role of SA similarly to JA might be limited to a transient and rapid increase at the onset of the first period of stress.

  9. Renal excretion of water-soluble contrast media after enema in the neonatal period.

    Science.gov (United States)

    Kim, Hee Sun; Je, Bo-Kyung; Cha, Sang Hoon; Choi, Byung Min; Lee, Ki Yeol; Lee, Seung Hwa

    2014-08-01

    When abdominal distention occurs or bowel obstruction is suspected in the neonatal period, a water-soluble contrast enema is helpful for diagnostic and therapeutic purposes. The water-soluble contrast medium is evacuated through the anus as well as excreted via the kidneys in some babies. This study was designed to evaluate the incidence of renal excretion after enemas using water-soluble contrast media and presume the causes. Contrast enemas using diluted water-soluble contrast media were performed in 23 patients under 2 months of age. After the enema, patients were followed with simple abdominal radiographs to assess the improvement in bowel distention, and we could also detect the presence of renal excretion of contrast media on the radiographs. Reviewing the medical records and imaging studies, including enemas and consecutive abdominal radiographs, we evaluated the incidence of renal excretion of water-soluble contrast media and counted the stay duration of contrast media in urinary tract, bladder, and colon. Among 23 patients, 12 patients (52%) experienced the renal excretion of water-soluble contrast media. In these patients, stay-in-bladder durations of contrast media were 1-3 days and stay-in-colon durations of contrast media were 1-10 days, while stay-in-colon durations of contrast media were 1-3 days in the patients not showing renal excretion of contrast media. The Mann-Whitney test for stay-in-colon durations demonstrated the later evacuation of contrast media in the patients with renal excretion of contrast media (p = 0.07). The review of the medical records showed that 19 patients were finally diagnosed as intestinal diseases, including Hirschsprung's disease, meconium ileum, meconium plug syndrome, and small bowel atresia or stenosis. Fisher's exact test between the presence of urinary excretion and intestinal diseases indicated a statistically significant difference (p = 0.04). The intestinal diseases causing bowel obstruction may increase the

  10. Hydrology of surface waters and thermohaline circulation during the last glacial period; Hydrologie des eaux de surface et circulation thermohaline au cours de la derniere periode glaciaire

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, L.

    1996-03-27

    Sedimentological studies on oceanic cores from the north Atlantic have revealed, over the last glacial period, abrupt climatic changes with a periodicity of several thousand years which contrasts strongly with the glacial-interglacial periodicity (several tens of thousand years). These periods of abrupt climate changes correspond to massive icebergs discharges into the north Atlantic. The aim of this work was to study the evolution of the thermohaline circulation in relation to these episodic iceberg discharges which punctuated the last 60 ka. To reconstruct the oceanic circulation in the past, we have analysed oxygen and carbon stable isotopes on benthic foraminifera from north Atlantic deep-sea cores. First of all, the higher temporal resolution of sedimentary records has enabled us to establish a precise chrono-stratigraphy for the different cores. Then, we have shown the close linkage between surface water hydrology and deep circulation, giving evidence of the sensibility of thermohaline circulation to melt water input in the north Atlantic ocean. Indeed, changes in deep circulation are synchronous from those identified in surface waters and are recorded on a period which lasted {approx} 1500 years. Deep circulation reconstructions, before and during a typical iceberg discharge reveal several modes of circulation linked to different convection sites at the high latitudes of the Atlantic basin. Moreover, the study of the last glacial period gives the opportunity to differentiate circulation changes due to the external forcing (variations of the orbital parameters) and those linked to a more local forcing (icebergs discharges). 105 refs., 50 figs., 14 tabs., 4 appends.

  11. Drift dives and prolonged surfacing periods in Baikal seals: resting strategies in open waters?

    Science.gov (United States)

    Watanabe, Yuuki Y; Baranov, Eugene A; Miyazaki, Nobuyuki

    2015-09-01

    Many pinnipeds frequently rest on land or ice, but some species remain in open waters for weeks or months, raising the question of how they rest. A unique type of dive, called drift dives, has been reported for several pinnipeds with suggested functions of rest, food processing and predator avoidance. Prolonged surfacing periods have also been observed in captive seals and are thought to aid food processing. However, information from other species in a different environment would be required to better understand the nature and function of this behavior. In this study, we attached multi-sensor tags to Baikal seals Pusa sibirica, a rare, freshwater species that has no aquatic predators and few resting grounds during the ice-free season. The seals exhibited repeated drift dives (mean depth, 116 m; duration, 10.1 min) in the daytime and prolonged periods at the surface (mean duration, 1.3 h) mainly around dawn. Drift dives and prolonged surfacing periods were temporally associated and observed between a series of foraging dives, suggesting a similar function, i.e. a combination of resting and food processing. The maximum durations of both drift and foraging dives were 15.4 min, close to the aerobic dive limit of this species; therefore, metabolic rates might not be significantly depressed during drift dives, further supporting the function of food processing rather than purely resting. Our results also show that drift diving can occur in a predator-free environment, and thus predator avoidance is not a general explanation of drift dives in pinnipeds. © 2015. Published by The Company of Biologists Ltd.

  12. On steady electromagnetic equilibria

    Science.gov (United States)

    Lehnert, B.

    1986-12-01

    The existence of steady electromagnetic equilibrium states predicted by an extended Lorentz invariant formulation of Maxwell's equations is analyzed. General equilibrium solutions are outlined which lead to integrated field quantities of the system, such as total charge qo, magnetic moment Mo, mass mo and angular momentum so. The quantization of moMo/qo in terms of Bohr magnetons is shown to be equivalent to the proposed resonance condition of circulating self-confined radiation. Exact equilibrium solutions were deduced in two simple cases, thereby leading to a so of the same order as that of the electron, and to a qo one order of magnitude larger than the electronic charge. A variational procedure is suggested in search for states of minimum charge, under the subsidiary quantum conditions on moMo/qo and so, i.e., by varying the profile of the electric space charge distribution.

  13. WATER ACTIVITY INFLUENCE ON THE SAFE AGING PERIOD OF CONDENSED MILK

    OpenAIRE

    Ilona Šostakienė; Jūratė Blazgienė

    2010-01-01

    The majority of chemical and biological processes causing the change of nutrients and finally their spoilage are dependent on water. Microbiological growth is directly related to water activity. Water activity (aw) was introduced by an Australian microbiologist W.J. Scott in 1952. He defined this concept as a “fundamental property of water solutions” and i.e. a ratio between pure water (p0) and steam pressure solution (p). The water activity of the unsweetened condensed milk packed into canis...

  14. Renewable Energy Water Pumping Systems Handbook; Period of Performance: April 1--September 1, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Argaw, N.

    2004-07-01

    Water is one of the most basic necessities of rural development. This book provides valuable information on how renewable energy technologies can be used for irrigation, livestock watering, and domestic water supplies. This report emphasizes wind and solar energy resources, and hybrid water pumping systems.

  15. [Effects of deep plowing and mulch in fallow period on soil water and yield of wheat in dryland].

    Science.gov (United States)

    Deng, Yan; Gao, Zhi-Qiang; Sun, Min; Zhao, Wei-Feng; Zhao, Hong-Mei; Li, Qing

    2014-01-01

    A field test was carried out in Qiujialing Village, Wenxi, Shanxi from 2009 to 2011 to study the soil water movement of 0-300 cm layer, yield formation and water use efficiency (WUE) of wheat with deep plowing and mulching the whole ground immediately (no mulch as control) 15 days and 45 days after harvest. The results indicated that deep plowing and mulch in fallow period could improve soil water storage of the 100-180 cm layer before sowing, the soil water storage efficiency in fallow period, and soil water storage from pre-wintering stage to booting stage. Compared with deep plowing 15 days after wheat harvest, deep plowing 45 days after wheat harvest did better in improving soil water storage and water use efficiency, as well as ear number and yield, which was more conducive in the year with more precipitation. Generally, deep plowing and mulching after raining during fallow period could benefit the soil water storage and conservation, thus would be helpful to improve wheat yield in dryland.

  16. Features of water purification from Vuoksa river during the summer period

    OpenAIRE

    N.I. Vatin; V.N. Chechevichkin; A. V. Chechevichkin

    2010-01-01

    Purification of water from the river Vuoksi of the Karelian Isthmus of Russia to drinking water quality is important and serious problem.Fluctuations in the composition of these waters in the summer, not only related to the hydrometeorological situation, but with increasing human influence on the ecosystem of the river Vuoksi greatly complicate usually adopted for such waters coagulation treatment.The instability of such indicators of these waters, as alkalinity, permanganate oxidation and co...

  17. Contribution of the Steady State Method to Water Permeability Measurement in Very Low Permeability Porous Media Contribution de la méthode stationnaire dans les mesures des très faibles perméabilités à l’eau

    Directory of Open Access Journals (Sweden)

    Boulin P.F.

    2012-04-01

    Full Text Available Very low permeability geomaterials (order of nanoDarcy (10-21 m2, such as clay rocks, are of interest for many industrial applications including production from unconventional reserves of oil and gas, CO2 geological storage and deep geological disposal of high-level long-lived radioactive waste. In these last two applications, the efficiency of clay, as a barrier, relies on their very low permeability. Yet, laboratory measurement of low permeability to water (below 100 nD (10-19 m2 remains a technical challenge. Some authors (Hsieh et al., 1981, Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 18, 245-252 argue that steady state methods are irrelevant due to the time required to stabilize water fluxes in such low permeability media and prefer a transient technique called pulse decay. This study aims to perform and compare transient and steady state techniques on three samples. Regarding the steady state method, a high precision pump was used to measure water flow rate through the sample. We show that with a suitable set-up, the steady state method enables us to measure a very low permeability of 0.8 nD (8 × 10-22 m2 over a period of three days and 2.6 nD (2.6 × 10-21 m2 over a period of one day. While the pulse decay test provides only an average estimate of the permeability for a comparable duration. Many issues are raised in pulse decay tests: determination of the reservoirs storage factor, micro leakage effects, determination of the initial pulse pressure, 2D mechanical effect. Contrary to the widespread belief that transient techniques are required to measure very low permeability, we show that direct steady state measurement of water permeability, with suitable equipments, can be much faster and more accurate than measurement by pulse decay. In fact, low water and rock compressibilities result in fast propagation of pressure wave and it cannot be argued that steady state conditions are not reachable in a reasonable amount of time

  18. Hydrologic drought of water year 2011 compared to four major drought periods of the 20th century in Oklahoma

    Science.gov (United States)

    Shivers, Molly J.; Andrews, William J.

    2013-01-01

    Water year 2011 (October 1, 2010, through September 30, 2011) was a year of hydrologic drought (based on streamflow) in Oklahoma and the second-driest year to date (based on precipitation) since 1925. Drought conditions worsened substantially in the summer, with the highest monthly average temperature record for all States being broken by Oklahoma in July (89.1 degrees Fahrenheit), June being the second hottest and August being the hottest on record for those months for the State since 1895. Drought conditions continued into the fall, with all of the State continuing to be in severe to exceptional drought through the end of September. In addition to effects on streamflow and reservoirs, the 2011 drought increased damage from wildfires, led to declarations of states of emergency, water-use restrictions, and outdoor burning bans; caused at least $2 billion of losses in the agricultural sector and higher prices for food and other agricultural products; caused losses of tourism and wildlife; reduced hydropower generation; and lowered groundwater levels in State aquifers. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted an investigation to compare the severity of the 2011 drought with four previous major hydrologic drought periods during the 20th century – water years 1929–41, 1952–56, 1961–72, and 1976–81. The period of water years 1925–2011 was selected as the period of record because few continuous record streamflow-gaging stations existed before 1925, and gaps in time existed where no streamflow-gaging stations were operated before 1925. In water year 2011, statewide annual precipitation was the 2d lowest, statewide annual streamflow was 16th lowest, and statewide annual runoff was 42d lowest of those 87 years of record. Annual area-averaged precipitation totals by the nine National Weather Service climate divisions from water year 2011 were compared to those during four previous major hydrologic drought

  19. Temporal variation and spatial distribution of PAH in water of Three Gorges Reservoir during the complete impoundment period.

    Science.gov (United States)

    Wang, Jingxian; Henkelmann, Bernhard; Bi, Yonghong; Zhu, Kongxian; Pfister, Gerd; Hu, Wei; Temoka, Cedrique; Westrich, Bernhard; Schramm, Karl-Werner

    2013-10-01

    Bioavailable concentrations of polycyclic aromatic hydrocarbons (PAHs) were investigated in water of Three Gorges Reservoir (TGR) using semipermeable membrane devices during the period of completely impounding water. ∑PAH concentrations in water of TGR in the period of completely impounding water were 15-381 ng L(-1). ∑PAH concentrations increased from town or counties to big industrialized cities in TGR, indicating urbanization effects on PAH pollution in the water. Tributaries in TGR have a certain contribution of PAH pollution to the mainstream of Yangtze River and their pollution could not be neglected. An obvious decrease of PAH concentration was observed after 175-m water impounding in 2011 in TGR. Several factors may account for this decrease, including execution of comprehensive treatment and management measures in TGR, less rainfall in 2011, and sedimentation effect caused by the dam. Passive sampling method has been successfully applied in the investigation of trace PAH in water of TGR and proved to be a useful and efficient tool for the management and sustainable development of the big reservoir. The results of the study provide valuable information about PAH pollution in the whole reservoir including some tributaries, and the pollution status is dynamically related with human activities. Therefore, PAH could be used as a marker compound or indicator in the network monitoring system to surveil and trace the pollution status in TGR.

  20. Risk assessment of water security in Haihe River Basin during drought periods based on D-S evidence theory

    Directory of Open Access Journals (Sweden)

    Qian-jin DONG

    2014-04-01

    Full Text Available The weights of the drought risk index (DRI, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer (D-S evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. (2005, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.

  1. A Steady-State Head-to-Head Pharmacokinetic Comparison of All FK-506 (Tacrolimus) Formulations (ASTCOFF): An Open-Label, Prospective, Randomized, Two-Arm, Three-Period Crossover Study.

    Science.gov (United States)

    Tremblay, S; Nigro, V; Weinberg, J; Woodle, E S; Alloway, R R

    2017-02-01

    This two-sequence, three-period crossover study is the first pharmacokinetic (PK) study to compare all three innovator formulations of tacrolimus (twice-daily immediate-release tacrolimus capsules [IR-Tac]; once-daily extended-release tacrolimus capsules [ER-Tac]; novel once-daily tacrolimus tablets [LCPT]). Stable renal transplant patients were dosed with each drug for 7 days, and blood samples were obtained over 24 h. Thirty subjects were included in the PK analysis set. A conversion factor of 1:1:0.80 for IR-Tac:ER-Tac:LCPT was used; no dose adjustments were permitted during the study. The median (interquartile range) total daily dose was 6.0 (4.0-8.0) mg for IR-Tac and ER-Tac and 4.8 (3.3-6.3) for LCPT. Significantly higher exposure on a per milligram basis, lower intraday fluctuation and prolonged time (Tmax ) to peak concentration (Cmax ) were found for LCPT versus IR-Tac or ER-Tac. ER-Tac showed no differences versus IR-Tac in exposure, Cmax , Tmax or fluctuation. The observed exposure of IR-Tac was used to normalize exposure for LCPT and ER-Tac, resulting in the following recommended total daily dose conversion rates: IR-Tac:ER-Tac, +8%; IR-Tac:LCPT, -30%; ER-Tac:LCPT, -36%. After exposure normalization, Cmax was ~17% lower for LCPT than for IR-Tac or ER-Tac; Cmin was ~6% lower for LCPT compared with IR-Tac and 3% higher compared with ER-Tac. © 2016 The Authors. American Journal of Transplantation published by Wiley Periodicals, Inc. on behalf of American Society of Transplant Surgeons.

  2. Water Quality Assessment of the Los Angeles River Watershed, California, USA in Wet and Dry Weather Periods

    Science.gov (United States)

    Rezaie Boroon, M. H.; Von L Coo, C.

    2015-12-01

    The purpose of this study is to identify sources of potential pollutants and characterize urban water quality along the Los Angeles River from its head to the mouth during dry and wet weather periods. Los Angeles (LA) River flows through heavily populated urbanized area in the Los Angeles downtown. The LA River is an effluent-dominated water body during the dry season. The three waste water treatment plants (WWTP) including the Tillman, Burbank, and Glendale discharge the majority of the volume flowing in the LA River during the dry and wet period. The concentration values (ppm) for anions in the dry season ranging 5.5-16,027 (Cl), 0-1.0 (F), 0-21(NO3), 0-1.6 (PO4), and 13.3-2,312 (SO4); whereas the values (ppm) for anions in the wet season ranging 3.4-5,860 (Cl), 0-0.66 (F), 0-17 (NO3), 0-0.67 (PO4), 7.9- 745 (SO4). Dry season concentrations values for trace metals were obtained with values (ppb) ranging 0.9-10 (Ni), 0.8-62 (Zn), 1-4 (As), 0-1 (Pb) and 0-3 (Se). As for wet season trace metals (ppb) ranging 0.001-0.008 (Ni), 0.000001-0.038 (Zn), 0.0016-0.016 (As), 0.00099-0.0058 (Pb), 0.000001-0.0093 (Se). Higher concentrations values during the dry period in the LA River watershed may be attributed to the three WWTPs discharge (75% of the volume of water flowing in the LA River). In water-limited areas such as the Los Angeles basin, urban runoff is a water resource that could enhance restricted water supplies and to enhance localized renewable groundwater resources, thus an assessment of this precious water resource is important for local city and regulatory organizations. In water-limited areas such as the LA basin, urban runoff is a water resource that could enhance restricted water supplies and groundwater resources, thus an assessment of this precious water resource is important for local regulatory organizations.

  3. Combined Steady-State and Dynamic Heat Exchanger Experiment

    Science.gov (United States)

    Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

    2009-01-01

    This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

  4. Steady states in conformal theories

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    A novel conjecture regarding the steady state behavior of conformal field theories placed between two heat baths will be presented. Some verification of the conjecture will be provided in the context of fluid dynamics and holography.

  5. Sulfur bacteria in wastewater stabilization ponds periodically affected by the 'red-water' phenomenon

    NARCIS (Netherlands)

    Belila, A.; Abbas, B.; Fazaa, I.; Saidi, N.; Snoussi, M.; Hassen, A.; Muyzer, G.

    2013-01-01

    Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the ‘red-water’ phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El

  6. Spawning period and first maturity size of deep water rose shrimp ...

    African Journals Online (AJOL)

    Parapenaeus longirostris is one of the most important commercial crustaceans for the trawl fleet in the Aegean Sea. Spawning period and size at first sexual maturity of female P. longirostris were analysed from monthly samples collected by demersal trawls in the bay of Sıacık and Kuadası in the Aegean Sea, from May 2008 ...

  7. 75 FR 16363 - Beverages: Bottled Water; Reopening of the Comment Period

    Science.gov (United States)

    2010-04-01

    ... result in a limit on the level of this chemical in bottled water that conflicts with this chemical's... regulations. In the 1996 final rule, FDA stated that it was not aware of the potential conflict between the... Council Directive 85/572/EEC laying down the list of simulants to be used for testing migration of...

  8. Impact of length of calibration period on the APEX model water quantity and quality simulation performance

    Science.gov (United States)

    Availability of continuous long-term measured data for model calibration and validation is limited due to time and resources constraints. As a result, hydrologic and water quality models are calibrated and, if possible, validated when measured data is available. Past work reported on the impact of t...

  9. Decadal and shorter period variability of surf zone water quality at Huntington Beach, California.

    Science.gov (United States)

    Boehm, A B; Grant, S B; Kim, J H; Mowbray, S L; McGee, C D; Clark, C D; Foley, D M; Wellman, D E

    2002-09-15

    The concentration of fecal indicator bacteria in the surf zone at Huntington Beach, CA, varies over time scales that span at least 7 orders of magnitude, from minutes to decades. Sources of this variability include historical changes in the treatment and disposal of wastewater and dry weather runoff, El Niño events, seasonal variations in rainfall, spring-neap tidal cycles, sunlight-induced mortality of bacteria, and nearshore mixing. On average, total coliform concentrations have decreased over the past 43 years, although point sources of shoreline contamination (storm drains, river outlets, and submarine outfalls) continue to cause transiently poor water quality. These transient point sources typically persist for 5-8 yr and are modulated by the phase of the moon, reflecting the influence of tides on the sourcing and transport of pollutants in the coastal ocean. Indicator bacteria are very sensitive to sunlight therefore, the time of day when samples are collected can influence the outcome of water quality testing. These results demonstrate that coastal water quality is forced by a complex combination of local and external processes and raise questions about the efficacy of existing marine bathing water monitoring and reporting programs.

  10. The risk of river pollution due to washout from contaminated floodplain water bodies during periods of high magnitude floods

    Science.gov (United States)

    Lyubimova, T.; Lepikhin, A.; Parshakova, Ya.; Tiunov, A.

    2016-03-01

    The risk of river pollution due to washout (removal of pollutants) from contaminated floodplain water bodies (floodplain lakes and quarries whose origin is related to the large-scale mining of nonmetallic building materials in the floodplain zone) during high magnitude flood periods is analyzed using a combination of one-, two- and three-dimensional hydrodynamic modeling and in situ measurements. The modeling performed for the floodplain water bodies contaminated by N compounds shows that during large magnitude floods washout occurs. The washout process consists of two stages: an initial rapid stage lasting about two hours during which the upper (3-4 m thick) layer is washed out, followed by a second stage when the concentration of NH4-N in the floodplain water body remains nearly constant. The maximum contaminant concentration in the river in the vicinity of a water intake for drinking water located 21 km downstream is attained about 9 h from the beginning of the flood; concentration of NH4-N can reach values several times larger than acceptable concentration guidelines. The initial primary peak in contaminant concentration at the water intake is followed by a slight decrease in contaminant concentration; a second peak related to the contaminant transport through the inundated floodplain subsequently occurs, after which the concentration slowly decreases, reaching acceptable values after 30-40 h. Contaminated floodplain water bodies located near drinking water supply systems are not significant sources of contamination during small and moderate floods, but during high magnitude floods, they can become sources of water pollution. Operational measures that can decrease potential health risks are discussed.

  11. Chlorination of iodide-containing waters in the presence of CuO: Formation of periodate

    KAUST Repository

    Liu, Chao

    2014-11-18

    It has been shown previously that the disproportionation of halogen-containing oxidants (e.g., HOCl, HOBr, and ClO2) is enhanced by a CuO-catalyzed process. In this study, the transformation of iodine during chlorination in the presence of CuO was investigated. There is no significant enhancement of the disproportionation of hypoiodous acid (HOI) in the presence of CuO. The formation rate of iodate (IO3 -) in the CuO-HOCl-I- system significantly increased when compared to homogeneous solutions, which was ascribed to the activation of HOCl by CuO enhancing its reactivity toward HOI. In this reaction system, iodate formation rates increase with increasing CuO (0-0.5 g L-1) and bromide (0-2 μM) doses and with decreasing pH (9.6-6.6). Iodate does not adsorb to the CuO surfaces used in this study. Nevertheless, iodate concentrations decreased after a maximum was reached in the CuO-HOCl-I-(-Br-) systems. Similarly, the iodate concentrations decrease as a function of time in the CuO-HOCl-IO3 - or CuO-HOBr-IO3 - system, and the rates increase with decreasing pH (9.6-6.6) due to the enhanced reactivity of HOCl or HOBr in the presence of CuO. It could be demonstrated that iodate is oxidized to periodate by a CuO-activated hypohalous acid, which is adsorbed on the CuO surface. No periodate could be measured in filtered solutions because it was mainly adsorbed to CuO. The adsorbed periodate was identified by scanning electron microscopy plus energy dispersive spectroscopy and X-ray photoelectron spectroscopy.

  12. Fractal water quality fluctuations spanning the periodic table in an intensively farmed watershed.

    Science.gov (United States)

    Aubert, Alice H; Kirchner, James W; Gascuel-Odoux, Chantal; Faucheux, Mikael; Gruau, Gérard; Mérot, Philippe

    2014-01-21

    Recently developed measurement technologies can monitor surface water quality almost continuously, creating high-frequency multiparameter time series and raising the question of how best to extract insights from such rich data sets. Here we use spectral analysis to characterize the variability of water quality at the AgrHys observatory (Western France) over time scales ranging from 20 min to 12 years. Three years of daily sampling at the intensively farmed Kervidy-Naizin watershed reveal universal 1/f scaling for all 36 solutes, yielding spectral slopes of 1.05 ± 0.11 (mean ± standard deviation). These 36 solute concentrations show varying degrees of annual cycling, suggesting different controls on watershed export processes. Twelve years of daily samples of SO4, NO3, and dissolved organic carbon (DOC) show that 1/f scaling does not continue at frequencies below 1/year in those constituents, whereas a 12-year daily record of Cl shows a general 1/f trend down to the lowest measurable frequencies. Conversely, approximately 12 months of 20 min NO3 and DOC measurements show that at frequencies higher than 1/day, the spectra of these solutes steepen to slopes of roughly 3, and at time scales shorter than 2-3 h, the spectra flatten to slopes near zero, reflecting analytical noise. These results confirm and extend the recent discovery of universal fractal 1/f scaling in water quality at the relatively pristine Plynlimon watershed in Wales, further demonstrating the importance of advective-dispersive transport mixing in catchments. However, the steeper scaling at subdaily time scales suggests additional short-term damping of solute concentrations, potentially due to in-stream or riparian processes.

  13. Task related doses in Spanish pressurized water reactors over the period 1988-1992

    Energy Technology Data Exchange (ETDEWEB)

    O`Donnell, P.; Labarta, T.; Amor, I. [Subdireccion de Proteccion Radiologica, Madrid (Spain)

    1995-03-01

    In order to evaluate in depth the collective dose trend and its correlation with the effectiveness of the practical application of the ALARA principle in Spanish nuclear facilities, and base the different policy lines to promote this criteria, the CSN has fullfilled an analysis of the task related doses data over the period 1988-1992. Previously, the CSN had required to the utilities the compilation of their refuelling outage collective dose from 1988 according with a predeterminate number of tasks, in order to have available a representative and retrospective set of data in an homogeneous way and coherent with the international data banks on occupational exposure in NPP, as the CEC and the NEA ones. The scope of this analysis was the following: first, the collective dose summaries for outage tasks and departments for PWR and for BWR, including the minimum, maximum and average dose (and statistics data) for 18 different refuelling outage tasks and 12 personal departments for each generation of each type of rector, the task and department related collective dose trends in each plant and in each generation, and second, the dose reduction techniques having been used during that period in each plant and the relative level of adoption. In this presentation the main results and conclusions of the first part of the study are reviewed for PWR.

  14. Periodic Density Functional Theory Study of Water Adsorption on the a-Quartz (101) Surface.

    Energy Technology Data Exchange (ETDEWEB)

    Bandura, Andrei V. [St. Petersburg State University, St. Petersburg, Russia; Kubicki, James D. [Pennsylvania State University; Sofo, Jorge O. [Pennsylvania State University

    2011-01-01

    Plane wave density functional theory (DFT) calculations have been performed to study the atomic structure, preferred H2O adsorption sites, adsorption energies, and vibrational frequencies for water adsorption on the R-quartz (101) surface. Surface energies and atomic displacements on the vacuum-reconstructed, hydrolyzed, and solvated surfaces have been calculated and compared with available experimental and theoretical data. By considering different initial positions of H2O molecules, the most stable structures of water adsorption at different coverages have been determined. Calculated H2O adsorption energies are in the range -55 to -65 kJ/mol, consistent with experimental data. The lowest and the highest O-H stretching vibrational bands may be attributed to different states of silanol groups on the watercovered surface. The dissociation energy of the silanol group on the surface covered by the adsorption monolayer is estimated to be 80 kJ/mol. The metastable states for the protonated surface bridging O atoms (Obr), which may lead to hydrolysis of siloxane bonds, have been investigated. The calculated formation energy of a Q2 center from a Q3 center on the (101) surface with 2/3 dense monolayer coverage is equal to 70 kJ/mol which is in the range of experimental activation energies for quartz dissolution.

  15. Steady-State Process Modelling

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    This chapter covers the basic principles of steady state modelling and simulation using a number of case studies. Two principal approaches are illustrated that develop the unit operation models from first principles as well as through application of standard flowsheet simulators. The approaches...... illustrate the “equation oriented” approach as well as the “sequential modular” approach to solving complex flowsheets for steady state applications. The applications include the Williams-Otto plant, the hydrodealkylation (HDA) of toluene, conversion of ethylene to ethanol and a bio-ethanol process....

  16. Coccidiosis control by administering toltrazuril in the drinking water for a 2-day period.

    Science.gov (United States)

    Mathis, G F; Froyman, R; Kennedy, T

    2004-05-07

    A 56-day floor pen study was conducted to determine the appropriate time to administer toltrazuril (Baycox) (TOL) for control of coccidiosis in broiler chickens. Litter was seeded with field strains of Eimeria acervulina, Eimeria maxima and Eimeria tenella. On Days 0, 21, 35 and 56, all birds and feed were weighed. Starting on Day 14, weekly lesion scores and oocyst counts were performed. The treatments were 125 ppm nicarb (NIC) in the starter to 66 ppm salinomycin (SAL) in the grower with no TOL (NIC/SAL/no TOL), 66 ppm salinomycin in both the starter and the grower but no TOL (SAL/SAL/no TOL), or no in-feed medication with the following TOL treatment: TOL Days 2-3, TOL Days 6-7, TOL Days 10-11, TOL Days 14-15, TOL Days 18-19, and as control NM/NM/no TOL (NM). The withdrawal feed was nonmedicated. TOL was administered in the drinking water at the rate of 7 mg/kg body weight. Oocysts per gram litter and lesion scores showed a significant infection in the NM birds, which peaked about Day 21. The NIC/SAL gave excellent early protection but only moderate protection during the SAL phase. The final performance for the SAL/SAL was significantly less compared to all TOL and NIC/SAL birds. All TOL treatments but Days 2-3 provided good coccidiosis control with accompanying performance. The absence of clinical coccidiosis relapse during the last third of the growout along with moderate oocyst counts and low lesions was indicative of unimpaired coccidiosis immunity. It can be inferred from the overall results that the use of TOL as the sole anticoccidial for two consecutive days in the drinking water between Days 10 and 14 would be the best time for good coccidiosis control allowing full performance. Copyright 2004 Elsevier B.V.

  17. WATER REQUIREMENT ESTIMATE FOR THE REPRODUCTIVE PERIOD OF MANGO ORCHADS IN THE NORTHEAST OF THE STATE OF PARÁ, BRAZIL

    Directory of Open Access Journals (Sweden)

    PAULO JORGE DE OLIVEIRA PONTE DE SOUZA

    Full Text Available ABSTRACT The aim of this study was to estimate the water consumption in mango orchard during its phenological stages in the northeastern of the State of Pará, Brazil. For this purpose, it was installed and instrumented a micrometeorological tower in a mango orchard, cv. Tommy Atkins, of 22 years old, with data collected during the crops of 2010/2011 and of 2011/2012. The actual crop evapotranspiration was estimated from the energy balance using the Bowen ratio technique. The crops were subjected to different weather conditions, consequently, some differences in the Bowen ration values were observed. The evapotranspiration suffered influences of meteorological conditions during the period. The actual crop evapotranspiration during its reproductive period ranged between 402.9 and 420 mm with a mean daily water consumption of 3.8 mm at flowering, of 4.25 mm at fruit fall, of 3.56 mm at fruit formation, of 3.0 mm at fruit maturation and of 3.73 mm for the whole period.

  18. Changes of evapotranspiration and water yield in China's terrestrial ecosystems during the period from 2000 to 2010

    Science.gov (United States)

    Liu, Y.; Zhou, Y.; Ju, W.; Chen, J.; Wang, S.; He, H.; Wang, H.; Guan, D.; Zhao, F.; Li, Y.; Hao, Y.

    2013-04-01

    Terrestrial carbon and water cycles are interactively linked at various spatial and temporal scales. Evapotranspiration (ET) plays a key role in the terrestrial water cycle and altering carbon sequestration of terrestrial ecosystems. The study of ET and its response to climate and vegetation changes is critical in China since water availability is a limiting factor for the functioning of terrestrial ecosystems in vast arid and semiarid regions. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model was employed in conjunction with a newly developed leaf area index (LAI) dataset and other spatial data to simulate daily ET and water yield at a spatial resolution of 500 m over China for the period from 2000 to 2010. The spatial and temporal variations of ET and water yield and influences of temperature, precipitation, land cover types, and LAI on ET were analyzed. The validations with ET measured at 5 typical ChinaFLUX sites and inferred using statistical hydrological data in 10 basins showed that the BEPS model was able to simulate daily and annual ET well at site and basin scales. Simulated annual ET exhibited a distinguishable southeast to northwest decreasing gradient, corresponding to climate conditions and vegetation types. It increased with the increase of LAI in 74% of China's landmass and was positively correlated with temperature in most areas of southwest, south, east, and central China and with precipitation in the arid and semiarid areas of northwest and north China. In the Tibet Plateau and humid southeast China, the increase in precipitation might cause ET to decrease. The national mean annual ET varied from 345.5 mm yr-1 in 2001 to 387.8 mm yr-1 in 2005, with an average of 369.8 mm yr-1 during the study period. The overall increase rate of 1.7 mm yr-2 (r = 0.43 p = 0.19) was mainly driven by the increase of total ET in forests. During the period from 2006 to 2009, precipitation and LAI decreased widely and consequently

  19. Water management and land-use practices from the Iron-Age to the Roman period in Eastern Iberia

    OpenAIRE

    Orengo, H.A.; Ejarque, A.; Albiach, R.

    2014-01-01

    This study investigates water and land usage in the territory of La Carència, an Ibero-Roman city located near Turís (Valencia, Spain) in Eastern Iberia. The outstanding political importance of La Carència during the Iberian Iron-Age period is attested by its large size, the monumental character of its structures and on-site finds. Multidisciplinary and micro-regional landscape work at its territory documented significant differences between the Iberian and the Roman settlement patterns, whic...

  20. Analysis and modelling of non-steady flow in pipe and channel networks

    CERN Document Server

    Jovic, Vinko

    2013-01-01

    Analysis and Modelling of Non-Steady Flow in Pipe and Channel Networks deals with flows in pipes and channel networks from the standpoints of hydraulics and modelling techniques and methods. These engineering problems occur in the course of the design and construction of hydroenergy plants, water-supply and other systems. In this book, the author presents his experience in solving these problems from the early 1970s to the present day. During this period new methods of solving hydraulic problems have evolved, due to the development of computers and numerical methods. This book

  1. Rock bream iridovirus (RBIV) replication in rock bream (Oplegnathus fasciatus) exposed for different time periods to susceptible water temperatures.

    Science.gov (United States)

    Jung, Myung-Hwa; Nikapitiya, Chamilani; Vinay, Tharabenahalli-Nagaraju; Lee, Jehee; Jung, Sung-Ju

    2017-11-01

    Rock bream iridovirus (RBIV) is a member of the Megalocytivirus genus that causes severe mortality to rock bream. Water temperature is known to affect the immune system and susceptibility of fish to RBIV infection. In this study, we evaluated the time dependent virus replication pattern and time required to completely eliminate virus from the rock bream body against RBIV infection at different water temperature conditions. The rock bream was exposed to the virus and held at 7 (group A1), 4 (group A2) and 2 days (group A3) at 23 °C before the water temperature was reduced to 17 °C. A total of 28% mortality was observed 24-35 days post infection (dpi) in only the 7 day exposure group at 23 °C. In all 23 °C exposure groups, virus replication peaked at 20 to 22 dpi (10 6 -10 7 /μl). In recovery stages (30-100 dpi), the virus copy number was gradually reduced, from 10 6 to 10 1 with faster decreases in the shorter exposure period group at 23 °C. When the water temperature was increased in surviving fish from 17 to 26 °C at 70 dpi, they did not show any mortality or signs of disease and had low virus copy numbers (below 10 2 /μl). Thus, fish need at least 50 days from peaked RBIV levels (approximately 20-25 dpi) to inhibit the virus. This indicates that maintaining the fish at low water temperature (17 °C) for 70 days is sufficient to eradicate RBIV from fish body. Thus, RBIV could be eliminated slowly from the fish body and the virus may be completely eliminated under the threshold of causing mortality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Assessment of the anthropogenic component in the formation of extreme low-water periods based on remote sensing (case study for Russian south region)

    Science.gov (United States)

    Mikhailukova, Polina; Kireeva, Maria; Ilich, Vlad; Sazonov, Alexey; Kharlamov, Maxim

    2017-04-01

    Extreme low flow periods on the rivers are one of the most hydrological hazards. The aim of the study is determine causes of these periods based on the analysis of in land use changes. The territory of research is Don river basin. There is an assumption that the changes of Don watershed determines the increased duration of low-water periods, degradation of the river system of the region and the hard deficit of water resources. Authors analyzed archive of Landsat imagery for Don river basin for key time periods. The first key period is the middle 1970s - it was period of intensive land use on watershed. The second - is the middle 1990s characterized by decreasing rate of agriculture and increasing the area of abandoned lands. The third period is the middle 2000s when the rate of land use had started to increase. And the last period - 2014-2015 years, when low-water periods in Don river basin had become a disaster. We create mosaic of satellite images for each period and then classified it for several classes - urban area, different type of agricultural fields, forest, ponds and reservoirs. The analysis of classification results is demonstrate land use dynamic during last 45 years. The watershed changes was one the many reason of losses of the snowmelt runoff, which together with climate changes greatly increased the low-water period in the Don river basin. This research was supported by Russian President Grant 2017 (contract No. MK-2331.2017.5)

  3. Analysis of uncertainties, associated to the calculating hypothesis, in discharge tables for high flows estimating, based on mathematics models for calculating water surface profiles fore steady gradually varied flow; Analisis de las incertidumbres, asociadas a las hipotesis de calculo, en la estimacion de curvas de gasto para crcidas, basada en el empleo de modelo matematico de calculo hidraulico en regimen permanente

    Energy Technology Data Exchange (ETDEWEB)

    Aldana Valverde, A. L.; Gonzalez Rodriguez, J. C.

    1999-08-01

    In this paper are analyzed some of the most important factors which can influence on the results of calculating water surface profiles for steady gradually varied flow. In this case, the objective of this kind of modeling, has been the estimation of discharges tables for high flows of river station gages connected to the hydrologic automatic information system (SAIH) of the Confederacion Hidrografica del Sur de Espana, system named red Hidrosur. (Author) 3 refs

  4. Steady-State Equilibrium Phase Inversion Recovery ON-resonant Water Suppression (IRON) Magnetic Resonance Angiography in Conjunction with Superparamagnetic Nanoparticles. A Robust Technique for Imaging within a Wide Range of Contrast Agent Dosages

    Science.gov (United States)

    Gitsioudis, Gitsios; Stuber, Matthias; Arend, Ingolf; Thomas, Moritz; Yu, Jing; Hilbel, Thomas; Giannitsis, Evangelos; Katus, Hugo A.; Korosoglou, Grigorios

    2012-01-01

    Objectives To investigate the ability of inversion recovery ON-resonant water suppression (IRON) in conjunction with P904 (superparamagnetic nanoparticles which consisting of a maghemite core coated with a low-molecular-weight amino-alcohol derivative of glucose) to perform steady-state equilibrium phase magnetic resonance angiography (MRA) over a wide dose range. Materials and Methods Experiments were approved by the institutional animal care committee. Rabbits (n=12) were imaged at baseline and serially after the administration of 10 incremental dosages of 0.57–5.7 mgFe/Kg P904. Conventional T1-weighted and IRON MRA were obtained on a clinical 1.5-T scanner to image the thoracic and abdominal aorta, and peripheral vessels. Contrast-to-noise ratios (CNR) and vessel sharpness were quantified. Results Using IRON MRA, CNR and vessel sharpness progressively increased with incremental dosages of the contrast agent P904, exhibiting constantly higher contrast values than T1-weighted MRA over a very wide range of contrast agent doses (CNR of 18.8±5.6 for IRON versus 11.1±2.8 for T1-weighted MRA at 1.71 mgFe/kg, p=0.02 and 19.8±5.9 for IRON versus −0.8±1.4 for T1-weighted MRA at 3.99 mgFe/kg, p=0.0002). Similar results were obtained for vessel sharpness in peripheral vessels, (Vessel sharpness of 46.76±6.48% for IRON versus 33.20±3.53% for T1-weighted MRA at 1.71 mgFe/Kg, p=0.002, and of 48.66±5.50% for IRON versus 19.00±7.41% for T1-weighted MRA at 3.99 mgFe/Kg, p=0.003). Conclusion Our study suggests that quantitative CNR and vessel sharpness after the injection of P904 are consistently higher for IRON MRA when compared to conventional T1-weighted MRA. These findings apply for a wide range of contrast agent dosages. PMID:23418107

  5. Motion of the seawater interface in a coastal aquifer by the method of successive steady states

    Science.gov (United States)

    Bear, J.; Shamir, U.; Gamliel, A.; Shapiro, A. M.

    1985-01-01

    The paper describes a method for determining the motion of the seawater interface in a phreatic coastal aquifer during a specified time period in response to changing hydrologic conditions, provided a seaward flow of fresh water is maintained everywhere above the interface. The method of successive steady states is used, leading to an approximate analytical expression which gives the motion of the interface toe during the time period as a function of the initial conditions and the change in freshwater flow to the sea above the toe during the time period. Sensitivity of the results to values of parameters and to hydrologic conditions is investigated, and the results are compared with those obtained by other methods of analysis. The motivation for developing the approximate analytical expression for movement of the interface was to facilitate the introduction of seawater intrusion as a criterion in the multiobjective management model for coastal aquifers.

  6. Evidence of a warm early instrumental period found in temperature related water isotope records from high elevation Alpine ice cores

    Science.gov (United States)

    Bohleber, Pascal; Schöner, Wolfgang; Wagenbach, Dietmar

    2015-04-01

    The variability of water isotopes (delta-O18 or delta-D) preserved in Alpine glacier ice may provide mid-latitude temperature proxy records supplementing respective information from other archives. In order to archive long term records (i.e. exceeding 100 years) the limited glacier depth at suitable Alpine drill sites requires a relatively low net accumulation rate. In this respect, the cold glacier saddle Colle Gnifetti (CG) is the unique drilling site in the European Alps offering ice core records substantially exceeding the instrumental period. However, the unique low net accumulation at CG is characterised by strong spatio-temporal variability causing depositional noise that strongly challenges the interpretation of the ice core isotope records in terms of net temperature change. Here we present our findings from comparing stable water isotope records of the CG multi core array to a site-specific temperature time series. The latter is synthesized from high elevation stations of the instrumental HISTALP network considering among others the temperature shift from the accumulation bias towards growing seasons. Within the last century dedicated time series analysis reveals a common signal in the (supra-) decadal components of the instrumental temperature and isotope records. Extending the comparison over the entire 250 years instrumental period, systematic discrepancies are found within the early instrumental period (EIP). The delta-O18 record shows an overall decreasing trend from 1760 to 1890 AD, which is not reflected in the temperature record. However, using high Alpine summer temperature lacking the latest EIP adjustment, the long-term trends between isotope and instrumental data are in better agreement. The overall mean of the isotope based temperature in the EIP indicates substantially warmer levels than the EIP-corrected instrumental temperature. It differs, however, not significantly with respect to the non-EIP-corrected temperature mean. Although the main

  7. Observations of long-period waves in the nearshore waters of central west coast of India during the fall inter-monsoon period

    Digital Repository Service at National Institute of Oceanography (India)

    Amrutha, M.M.; SanilKumar, V.; Jesbin, G.

    The waves measured in the eastern Arabian Sea during the fall inter-monsoon period (October) are examined at 4 locations during 2010–2015. Multi-modal features have been observed in measured wave spectra due to independent wave systems corresponding...

  8. Do steady fast magnetic dynamos exist?

    Science.gov (United States)

    Finn, John M.; Ott, Edward; Hanson, James D.; Kan, Ittai

    1989-01-01

    This paper considers the question of the existense of a steady fast kinematic magnetic dynamo for a conducting fluid with a steady velocity field and vanishingly small electrical resistivity. The analysis of examples of steady dynamos, found by considering the zero-resistivity dynamics, indicated that, for sufficiently small resistivity, dynamo action can indeed occur in steady smooth three-dimensional chaotic fluid flows and that fast dynamos should consequently be a typical occurrence for such flows.

  9. Thirst perception in dehydrated sickle cell disease patients in steady ...

    African Journals Online (AJOL)

    Liberal fluid intake is one of the key management strategies in sickle cell anaemia (SCA) patients in steady state, but less work has been done on the desire of patients to drink water. Using the Visual Analogue Scale we studied thirst perception (TP) in 20 euhydrated SCA patients and 28 control (HbA) subjects, as well as ...

  10. thirst perception in dehydrated sickle cell disease patients in steady ...

    African Journals Online (AJOL)

    Daniel Owu

    Summary: Liberal fluid intake is one of the key management strategies in sickle cell anaemia (SCA) patients in steady state, but less work has been done on the desire of patients to drink water. Using the Visual Analogue. Scale we studied thirst perception (TP) in 20 euhydrated SCA patients and 28 control (HbA) subjects, ...

  11. Effect of temperature on incubation period, embryonic mortality, hatch rate, egg water loss and partridge chick weight (Rhynchotus rufescens

    Directory of Open Access Journals (Sweden)

    Nakage ES

    2003-01-01

    Full Text Available The aim of this study was to determine the effects of incubation temperature (34.5; 35.5; 36.5; 37.5 and 38.5ºC, on incubation period, embryonic mortality, hatching rate, water loss and chick weight at hatch, using daily incubation of partridge (Rhynchotus rufescens eggs. The highest hatching percentage was obtained between 35.5 and 36.5ºC. Incubation length and temperature were inversely proportional. Water loss was lower in eggs incubated at low temperatures as compared to high temperatures. There was no difference among incubation temperatures in absolute and relative hatchling weights. Early embryonic mortality increased at low temperatures (36.5ºC. Our results show that, under conditions of daily incubation of eggs in the same incubator, higher hatching rate can be obtained using temperatures between 35.5ºC and 36.5ºC; incubation temperature is inversely proportional to incubation length, and absolute and relative weights of partridge chicks are not affected by incubation temperature.

  12. Resource Conservation and Recovery Act ground-water monitoring projects for Hanford facilities: Progress report for the period October 1 to December 31, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.M.; Bates, D.J.; Lundgren, R.E. (eds.)

    1990-03-01

    This is Volume 1 of a two-volume document that describes the progress of 15 Hanford Site ground-water monitoring projects for the period October 1 to December 31, 1989. This volume discusses the projects. The work described in this document is conducted by the Pacific Northwest Laboratory under the management of Westinghouse Hanford Company for the US Department of Energy. Concentrations of ground-water constituents are compared to federal drinking water standards throughout this document for reference purposes. All drinking water supplied from the samples aquifer meets regulatory standards for drinking water quality. 51 refs., 35 figs., 86 tabs.

  13. Steady State Vapor Bubble in Pool Boiling.

    Science.gov (United States)

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C; Maroo, Shalabh C

    2016-02-03

    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  14. Steady state or non-steady state? Identifying driving mechanisms of oxygen isotope signatures of leaf transpiration in functionally distinct plant species

    Science.gov (United States)

    Dubbert, Maren; Kübert, Angelika; Cuntz, Matthias; Werner, Christiane

    2015-04-01

    Isotope techniques are widely applied in ecosystem studies. For example, isoflux models are used to separate soil evaporation from transpiration in ecosystems. These models often assume that plant transpiration occurs at isotopic steady state, i.e. that the transpired water shows the same isotopic signature as the source water. Yet, several studies found that transpiration did not occur at isotopic steady state, under both controlled and field conditions. Here we focused on identifying the internal and external factors which drive the isotopic signature of leaf transpiration. Using cavity ring-down spectroscopy (CRDS), the effect of both environmental variables and leaf physiological traits on δ18OT was investigated under controlled conditions. Six plant species with distinct leaf physiological traits were exposed to step changes in relative air humidity (RH), their response in δ18OT and gas exchange parameters and their leaf physiological traits were assessed. Moreover, two functionally distinct plant types (tree, i.e. Quercus suber, and grassland) of a semi-arid Mediterranean oak-woodland where observed under natural conditions throughout an entire growth period in the field. The species differed substantially in their leaf physiological traits and their turn-over times of leaf water. They could be grouped in species with fast (240 min.) turn-over times, mostly due to differences in stomatal conductance, leaf water content or a combination of both. Changes in RH caused an immediate response in δ18OT, which were similarly strong in all species, while leaf physiological traits affected the subsequent response in δ18OT. The turn-over time of leaf water determined the speed of return to the isotopic steady or a stable δ18OT value (Dubbert & Kübert et al., in prep.). Under natural conditions, changes in environmental conditions over the diurnal cycle had a huge impact on the diurnal development of δ18OT in both observed plant functional types. However, in

  15. Water erosion during a 17-year period under two crop rotations in four soil management systems on a Southbrazilian Inceptisol

    Science.gov (United States)

    Bertol, Ildegardis; Vidal Vázquez, Eva; Paz Ferreiro, Jorge

    2010-05-01

    Soil erosion still remains a persistent issue in the world, and this in spite of the efforts to ameliorate soil management systems taken into account the point of view of environmental protection against soil losses. In South Brazil water erosion is mainly associated to rainfall events with a great volume and high intensity, which are more or less evenly distributed all over the year. Nowadays, direct drilling is the most widely soil management system used for the main crops of the region. However, some crops still are grown on conventionally tilled soils, which means mainly ploughing and harrowing and less frequently chisel ploughing. In Lages-Santa Catarina State, Brazil, a plot experiment under natural rain was started in 1992 on an Inceptisol with the aim of quantifying soil and water losses. Treatments included bare and vegetated plots. The crop succession was: oats (Avena strigosa), soybean (Glycine max), vetch (Vicia sativa), maize (Zea mays), fodder radish (Raphanus sativus) and beans (Phaseolus vulgaris). Soil tillage systems investigated in this study were: i) conventional tillage (CT), ii) reduced tillage (MT), iii) no tillage (NT) under crop rotation and iv) conventional tillage on bare soil (BS). Treatments CT and BS involved ploughing plus twice harrowing, whereas MT involved chisel ploughing plus harrowing. Rainfall erosivity from January 1 1992 to December 31 2009 was calculated. Soil losses from the BS treatment along the 17 year study period were higher than 1200 Mg ha-1. Crop cover significantly reduced erosion, so that under some crops soil losses in the CT treatment were 80% lower than in the BS treatment. In turn soil losses in the MT treatment, where tillage was performed by chiselling and harrowing, were on average about 50% lower than in the CT treatment. No tillage was the most efficient soil management system in reducing soil erosion, so that soil losses in the NT treatment were about 98% lower than in the BS treatment. The three

  16. Resource Conservation and Recovery Act ground-water monitoring projects for Hanford Facilities: Progress report for the period July 1 to September 30, 1989 - Volume 1 - Text

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.M.; Bates, D.J.; Lundgren, R.E.

    1989-12-01

    This is Volume 1 of a two-volume document that describes the progress of 14 Hanford Site ground-water monitoring projects for the period July 1 to September 30, 1989. This volume discusses the projects; Volume 2 provides as-built diagrams, completion/inspection reports, drilling logs, and geophysical logs for wells drilled, completed, or logged during this period. Volume 2 can be found on microfiche in the back pocket of Volume 1. The work described in this document is conducted by the Pacific Northwest Laboratory under the management of Westinghouse Hanford Company for the US Department of Energy. Concentrations of ground-water constituents are compared to federal drinking water standards throughout this document for reference purposes. All drinking water supplied from the sampled aquifer meets regulatory standards for drinking water quality.

  17. Mechanism for multiplicity of steady states with distinct cell concentration in continuous culture of mammalian cells.

    Science.gov (United States)

    Yongky, Andrew; Lee, Jongchan; Le, Tung; Mulukutla, Bhanu Chandra; Daoutidis, Prodromos; Hu, Wei-Shou

    2015-07-01

    Continuous culture for the production of biopharmaceutical proteins offers the possibility of steady state operations and thus more consistent product quality and increased productivity. Under some conditions, multiplicity of steady states has been observed in continuous cultures of mammalian cells, wherein with the same dilution rate and feed nutrient composition, steady states with very different cell and product concentrations may be reached. At those different steady states, cells may exhibit a high glycolysis flux with high lactate production and low cell concentration, or a low glycolysis flux with low lactate and high cell concentration. These different steady states, with different cell concentration, also have different productivity. Developing a mechanistic understanding of the occurrence of steady state multiplicity and devising a strategy to steer the culture toward the desired steady state is critical. We establish a multi-scale kinetic model that integrates a mechanistic intracellular metabolic model and cell growth model in a continuous bioreactor. We show that steady state multiplicity exists in a range of dilution rate in continuous culture as a result of the bistable behavior in glycolysis. The insights from the model were used to devise strategies to guide the culture to the desired steady state in the multiple steady state region. The model provides a guideline principle in the design of continuous culture processes of mammalian cells. © 2015 Wiley Periodicals, Inc.

  18. Microbial consortia at steady supply

    Science.gov (United States)

    Taillefumier, Thibaud; Posfai, Anna; Meir, Yigal; Wingreen, Ned S

    2017-01-01

    Metagenomics has revealed hundreds of species in almost all microbiota. In a few well-studied cases, microbial communities have been observed to coordinate their metabolic fluxes. In principle, microbes can divide tasks to reap the benefits of specialization, as in human economies. However, the benefits and stability of an economy of microbial specialists are far from obvious. Here, we physically model the population dynamics of microbes that compete for steadily supplied resources. Importantly, we explicitly model the metabolic fluxes yielding cellular biomass production under the constraint of a limited enzyme budget. We find that population dynamics generally leads to the coexistence of different metabolic types. We establish that these microbial consortia act as cartels, whereby population dynamics pins down resource concentrations at values for which no other strategy can invade. Finally, we propose that at steady supply, cartels of competing strategies automatically yield maximum biomass, thereby achieving a collective optimum. DOI: http://dx.doi.org/10.7554/eLife.22644.001 PMID:28473032

  19. Renewable Energy in Water and Wastewater Treatment Applications; Period of Performance: April 1, 2001--September 1, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Argaw, N.

    2003-06-01

    This guidebook will help readers understand where and how renewable energy technologies can be used for water and wastewater treatment applications. It is specifically designed for rural and small urban center water supply and wastewater treatment applications. This guidebook also provides basic information for selecting water resources and for various kinds of commercially available water supply and wastewater treatment technologies and power sources currently in the market.

  20. Ground-water monitoring compliance projects for Hanford Site Facilities: Progress report for the period April 1--June 30, 1988: Volume 1, Text

    Energy Technology Data Exchange (ETDEWEB)

    1988-09-01

    This is Volume 1 of a two-volume set of documents that describes the progress of 10 Hanford Site ground-water monitoring projects for the period April 1 to June 30, 1988. This volume discusses the projects; Volume 2 provides as-built diagrams, drilling logs, and geophysical logs for wells drilled during this period in the 100-N Area and near the 216-A-36B Crib.

  1. Agricultural pollutant penetration and steady state in thick aquifers.

    Science.gov (United States)

    Kraft, G J; Browne, B A; Devita, W M; Mechenich, D J

    2008-01-01

    The leakage of pollutants from agricultural lands to aquifers has increased greatly, driven by increasing fertilizer and pesticide use. Because this increase is recent, ground water pollutant concentrations, loads, and exports may also be increasing as pollutants penetrate more deeply into aquifers. We established in an aquifer profile a ground water recharge and pollutant leakage chronology in an agricultural landscape where 30 m of till blankets a 57-m thick sandstone aquifer. Pollutant concentrations increased from older ground water (1963) at the aquifer base to younger ground water (1985) at its top, a signal of increasing pollutant leakage. Nitrate-N increased from 0.9 to 13.2 mg/L, implying that leakage increased from 1.9 to 16.5 kg/ha/year. Nitrate load and export could increase from 130% to 230% before reaching a steady state in 20 to 40 years. Chloride increases were similar. Pesticide residues alachlor ethane sulfonic acid (ESA), metolachlor ESA, and atrazine residues partially penetrated the aquifer profile. Their concentration-age-date patterns exhibited an initial increase and then a leveling corresponding to the timing of product adoption and leveling of demand. Unlike NO(3), projecting pesticide residue steady states is complicated by the phasing in and out of pesticide products over time; for example, neither alachlor nor atrazine is currently used in the area, and newer products, which have not had time to transit to the aquifer, have been adopted. The circumstances that resulted in the lack of a pollutant steady state are not rare; thus, the lack of steady states in agricultural region aquifers may not be uncommon.

  2. Exact Steady Azimuthal Edge Waves in Rotating Fluids

    Science.gov (United States)

    Ionescu-Kruse, Delia

    2017-09-01

    The full problem of water waves travelling along a constant sloping beach with the shoreline parallel to the Equator, written in a moving frame with the origin at a point on the rotating Earth is introduced. An exact steady solution of this problem moving only in the azimuthal direction, with no variations in this direction, is obtained. The solution is discussed in turn in spherical coordinates, in cylindrical coordinates and in the tangent-plan approximations.

  3. Dynamics of Water Content in Light Bare Soil in Summer Half-Year in the Period of 2003–2012 and its Agro-Meteorological Determinants

    Directory of Open Access Journals (Sweden)

    Biniak-Pieróg Małgorzata

    2014-10-01

    Full Text Available The objective of the study was the estimation of decade variation of water content in layers with thickness of 0–10, 0–20, 0–40 and 0–60 cm of a bare light brown soil in the summer half-year (May–October in the 10-year period of 2003–2012 against the background of agro-meteorological conditions. The study was based on results of measurement of the moisture of a bare soil with the use of the TDR method, sums of atmospheric precipitations and ground water levels, conducted in the area of the Agro- and Hydrometeorology Observatory of the Wrocław University of Environmental and Life Sciences, situated in Wrocław-Swojec. The analyses revealed slight variation of mean decade values of water content in the bare soil in the summer half-year during the ten-year period under analysis. Irrespective of the thickness of the soil layer, precipitation in the 10-year period of 2003–2012 had a highly significant effect on the water content in the 2nd decade of July. In the case of soil layers with thickness down to 0–20 cm a statistically significant relation between soil water content and ground water levels was noted for the 3rd decade of May, July, and in the 3rd decade of September. In the layer with thickness of 0–60 cm the relations were statistically significant almost throughout the summer half-year, with the exception of the 1st and 2nd decades of May. Analysis of trends of mean water content of the bare soil over the 10-year period of 2003–2012 indicated their statistically significant increase in the case of most of the decades of the summer half-year only in soil layers with thickness of 0–10 and 0–20 cm.

  4. Morphodynamics: Rivers beyond steady state

    National Research Council Canada - National Science Library

    Church, M; Ferguson, R. I

    2015-01-01

    .... River morphodynamics—an expression of bed material erosion, transport, and deposition—is the study of these interactions, the outcome of which is river morphology, hence it is appropriate to consider together advances in understanding bed material transport and morphodynamics. Over the past half century, Water Resources Research has been a significan...

  5. Infinite slope stability under steady unsaturated seepage conditions

    Science.gov (United States)

    Lu, N.; Godt, J.

    2008-01-01

    [1] We present a generalized framework for the stability of infinite slopes under steady unsaturated seepage conditions. The analytical framework allows the water table to be located at any depth below the ground surface and variation of soil suction and moisture content above the water table under steady infiltration conditions. The framework also explicitly considers the effect of weathering and porosity increase near the ground surface on changes in the friction angle of the soil. The factor of safety is conceptualized as a function of the depth within the vadose zone and can be reduced to the classical analytical solution for subaerial infinite slopes in the saturated zone. Slope stability analyses with hypothetical sandy and silty soils are conducted to illustrate the effectiveness of the framework. These analyses indicate that for hillslopes of both sandy and silty soils, failure can occur above the water table under steady infiltration conditions, which is consistent with some field observations that cannot be predicted by the classical infinite slope theory. A case study of shallow slope failures of sandy colluvium on steep coastal hillslopes near Seattle, Washington, is presented to examine the predictive utility of the proposed framework. Copyright 2008 by the American Geophysical Union.

  6. Asymmetry of agricultural water consumption in arid regions during alternating decadal scale wet and dry periods: explanation using behavioral economics

    Science.gov (United States)

    Tian, Fuqiang

    2017-04-01

    Increase of human water consumption for agriculture and consequent degradation of the ecological environment is a common feature in many arid regions. Understanding the driving mechanisms behind this phenomenon is of critical importance for regional sustainable development. In this study, analyses of temporal patterns of human water consumption are carried out in three hyper-arid inland basins, i.e., Aral Sea Basin in Central Asia, and the Tarim and Heihe River Basins in Northwestern China. Multi-decadal time series of hydrological and human consumption data are divided into decadal sequences of wet and dry years. During the wet phases, the greater water availability inspires economic expansion and human water consumption experiences growth at a rate faster than that of incoming water. During the dry phases, however, the expanded economy (e.g., irrigation land expansion in an agriculture-based economy) has been managed to sustain or even to increase production by over-exploitation of water with sophisticated technologies. Inability to reduce human water consumption at a rate commensurate with the decrease of incoming water supply leads to serious ecosystem degradation. This asymmetric human water consumption response of society to decadal scale hydrologic variability can be explained in terms of prospect theory drawn from behavioral economics, which states that people tend to be risk averse when facing gains and show risk preference when facing losses. In the three socio-hydrological case studies, direct economic gain/loss has relatively low value but high certainty when compared to indirect economic loss/gain (such as environmental or sustainability loss/gain), which has high value but with high uncertainty. According to prospect theory, people tend to gain direct economic benefits at the expense of environmental degradation and at the risk of system collapse. The outcomes of this study have major implications for water resources management at long time scales

  7. Renewable Energy for Water Pumping Applications In Rural Villages; Period of Performance: April 1, 2001--September 1, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Argaw, N.; Foster, R.; Ellis, A.

    2003-07-01

    This report introduces conventional and renewable energy sources for water pumping applications in rural villages by reviewing the technologies and illustrating typical applications. As energy sources for water pumping, the report discusses diesel/gasoline/kerosene engines, grid power supplies, traditional windmills, electrical wind turbines, and PV.

  8. Change the number of water reservoirs in the selected cities of the Upper Silesian Agglomeration over the period 1993-2014

    Directory of Open Access Journals (Sweden)

    Dąbrowska Dominika

    2015-06-01

    Full Text Available The Upper Silesian Agglomeration is the most industrialized area in Poland and one of the most in Europe. It is situated in the eastern part of the Upper Silesia and covers nearly 1500 km2. This region is highly diverse in terms of the spatial structure. There are lots of water reservoirs besides built-up areas and industrial facilities. Many of them have also significance for nature. Water reservoirs in the Upper Silesian Agglomeration function under anthropogenic conditions. Water reservoirs have a different size and the genesis. This kind of occurrence conditions influences the water reservoirs` state. There are mainly water reservoirs of anthropogenic character in a study area. A lot of water reservoirs are strictly connected with coal exploitation in this region. Unfortunately, the number of water reservoirs in the cities of the Upper Silesian Agglomeration has lately decreased. Reservoirs are eliminated as a result of changes in industry, progressive land development, changes in environmental conditions. In this paper we present the results of the number of water reservoirs analysis in Katowice, Sosnowiec and Chorzów over the period 1993-2014. Field studies and analysis of topographic maps show a decrease in the number of water reservoirs in this region by tens of percent.

  9. Non-Markovianity-assisted steady state entanglement.

    Science.gov (United States)

    Huelga, Susana F; Rivas, Ángel; Plenio, Martin B

    2012-04-20

    We analyze the steady state entanglement generated in a coherently coupled dimer system subject to dephasing noise as a function of the degree of Markovianity of the evolution. By keeping fixed the effective noise strength while varying the memory time of the environment, we demonstrate that non-Markovianity is an essential, quantifiable resource that may support the formation of steady state entanglement whereas purely Markovian dynamics governed by Lindblad master equations lead to separable steady states. This result illustrates possible mechanisms leading to long-lived entanglement in purely decohering, possibly local, environments. We present a feasible experimental demonstration of this noise assisted phenomenon using a system of trapped ions.

  10. Long-period effects of the Denali earthquake on water bodies in the Puget Lowland: Observations and modeling

    Science.gov (United States)

    Barberopoulou, A.; Qamar, A.; Pratt, T.L.; Steele, W.P.

    2006-01-01

    Analysis of strong-motion instrument recordings in Seattle, Washington, resulting from the 2002 Mw 7.9 Denali, Alaska, earthquake reveals that amplification in the 0.2-to 1.0-Hz frequency band is largely governed by the shallow sediments both inside and outside the sedimentary basins beneath the Puget Lowland. Sites above the deep sedimentary strata show additional seismic-wave amplification in the 0.04- to 0.2-Hz frequency range. Surface waves generated by the Mw 7.9 Denali, Alaska, earthquake of 3 November 2002 produced pronounced water waves across Washington state. The largest water waves coincided with the area of largest seismic-wave amplification underlain by the Seattle basin. In the current work, we present reports that show Lakes Union and Washington, both located on the Seattle basin, are susceptible to large water waves generated by large local earthquakes and teleseisms. A simple model of a water body is adopted to explain the generation of waves in water basins. This model provides reasonable estimates for the water-wave amplitudes in swimming pools during the Denali earthquake but appears to underestimate the waves observed in Lake Union.

  11. Water as a source of renewable energy. Recommendations and energy payback periods of eight techniques; Water als bron van duurzame energie. Aanbevelingen en energieterugverdientijden van acht technologieen

    Energy Technology Data Exchange (ETDEWEB)

    Van de Berg, M.; Geurts, F.; Stolk, N.

    2010-02-15

    This report describes the environmental impact of six energy technologies using water: thermal energy storage, tidal current, tidal energy with height of fall, wave energy, aquatic biomass and osmosis energy (blue energy) [Dutch] In dit rapport zijn de omgevingseffecten van zes energietechnologieen met water beschreven: warmte koude opslag, getijdenstroming, getijdenenergie op verval, golfenergie, aquatische biomassa en osmose-energie (blue energy)

  12. Penalty model for delay of bidding section construction period in South-to-North Water Diversion Eastern Route Project from perspective of programs

    Directory of Open Access Journals (Sweden)

    Jing-chun Feng

    2012-09-01

    Full Text Available According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculation of penalty for delay of the bidding section construction period with the critical path method, we studied the effects of contractor-induced delay of the bidding section construction period in detail, including the effects on the construction period of the bidding section itself, the earliest start times of the next bidding section and other subsequent bidding sections, and the construction period of the program, and then constructed a penalty model for delay of the bidding section construction period from the perspective of programs. Using the penalty model, we conducted a practical analysis of penalty for delay of the construction period of the Baoying station program in the South-to-North Water Diversion Project. The model can help determine the amount of penalty for delay of the construction period in bidding sections scientifically and reasonably.

  13. Ground-water monitoring compliance projects for Hanford Site facilities: Progress report for the period April 1 to June 30, 1988: Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1988-09-01

    This is Volume 2 of a two-volume set of documents that describes the progress of 10 Hanford Site ground-water monitoring projects for the period April 1 to June 30, 1988. This volume discusses as-built diagrams, drilling logs, and geophysical logs for wells drilled during this period in the 100-N Area (Appendix A) and near the 216-A-36B Crib (Appendix B). Volume 1 discusses the 10 projects. This work was supported by the US Department of Energy under Contract AC06-76RL01830.

  14. Ground-water monitoring compliance projects for Hanford Site facilities: Volume 1, The report and Appendix A, Progress report for the period October 1 to December 31, 1986

    Energy Technology Data Exchange (ETDEWEB)

    1987-02-01

    This report documents recent progress on ground-water monitoring projects for four Hanford Site facilities: the 300 Area Process Trenches, the 183-H Solar Evaporation Basins, the 200 Area Low-Level Burial Grounds, and the Nonradioactive Dangerous Waste (NRDW) Landfill. The existing ground-water monitoring projects for the first two facilities named in the paragraph above are currently being expanded by adding new wells to the networks. During the reporting period, sampling of the existing wells continued on a monthly basis, and the analytical results for samples collected from September through November 1986 are included and discussed in this document. 8 refs., 41 figs., 7 tabs.

  15. Reduced admixture of North Atlantic Deep Water to the deep central South Pacific during the last two glacial periods

    Science.gov (United States)

    Molina-Kescher, Mario; Frank, Martin; Tapia, Raúl; Ronge, Thomas A.; Nürnberg, Dirk; Tiedemann, Ralf

    2016-06-01

    The South Pacific is a sensitive location for the variability of the global oceanic thermohaline circulation given that deep waters from the Atlantic Ocean, the Southern Ocean, and the Pacific Basin are exchanged. Here we reconstruct the deep water circulation of the central South Pacific for the last two glacial cycles (from 240,000 years ago to the Holocene) based on radiogenic neodymium (Nd) and lead (Pb) isotope records complemented by benthic stable carbon data obtained from two sediment cores located on the flanks of the East Pacific Rise. The records show small but consistent glacial/interglacial changes in all three isotopic systems with interglacial average values of -5.8 and 18.757 for ɛNd and 206Pb/204Pb, respectively, whereas glacial averages are -5.3 and 18.744. Comparison of this variability of Circumpolar Deep Water (CDW) to previously published records along the pathway of the global thermohaline circulation is consistent with reduced admixture of North Atlantic Deep Water to CDW during cold stages. The absolute values and amplitudes of the benthic δ13C variations are essentially indistinguishable from other records of the Southern Hemisphere and confirm that the low central South Pacific sedimentation rates did not result in a significant reduction of the amplitude of any of the measured proxies. In addition, the combined detrital Nd and strontium (87Sr/86Sr) isotope signatures imply that Australian and New Zealand dust has remained the principal contributor of lithogenic material to the central South Pacific.

  16. Adaptation to High Temperature and Water Deficit in the Common Bean (Phaseolus vulgaris L. during the Reproductive Period

    Directory of Open Access Journals (Sweden)

    Hide Omae

    2012-01-01

    Full Text Available This paper reviews the adaption to heat and drought stresses in Phaseolus vulgaris, a grain and vegetable crop widely grown in both the Old and New World. Substantial genotypic differences are found in morphophysiological characteristics such as phenology, partitioning, plant-water relations, photosynthetic parameters, and shoot growth, which are related to reproductive responses. The associations between (a days to podding and leaf water content and (b the number of pods per plant and seed yield are consistent across different environments and experiments. Leaf water content is maintained by reductions in leaf water potential and shoot extension in response to heat and drought stress. Heat-tolerant cultivars have higher biomass allocation to pods and higher pod set in branches. These traits can be used as a marker to screen germplasm for heat and drought tolerance. In this paper, we briefly review the results of our studies carried out on heat and drought tolerance in the common bean at the Tropical Agriculture Research Front, Ishigaki, Japan.

  17. Quasi-steady state conditions in heterogeneous aquifers during pumping tests

    Science.gov (United States)

    Zha, Yuanyuan; Yeh, Tian-Chyi J.; Shi, Liangsheng; Huang, Shao-Yang; Wang, Wenke; Wen, Jet-Chau

    2017-08-01

    Classical Thiem's well hydraulic theory, other aquifer test analyses, and flow modeling efforts often assume the existence of ;quasi-steady; state conditions. That is, while drawdowns due to pumping continue to grow, the hydraulic gradient in the vicinity of the pumping well does not change significantly. These conditions have built upon two-dimensional and equivalent homogeneous conceptual models, but few field data have been available to affirm the existence of these conditions. Moreover, effects of heterogeneity and three-dimensional flow on this quasi-steady state concept have not been thoroughly investigated and discussed before. In this study, we first present a quantitative definition of quasi-steady state (or steady-shape conditions) and steady state conditions based on the analytical solution of two- or three-dimensional flow induced by pumping in unbounded, homogeneous aquifers. Afterward, we use a stochastic analysis to investigate the influence of heterogeneity on the quasi-steady state concept in heterogeneous aquifers. The results of the analysis indicate that the time to reach an approximate quasi-steady state in a heterogeneous aquifer could be quite different from that estimated based on a homogeneous model. We find that heterogeneity of aquifer properties, especially hydraulic conductivity, impedes the development of the quasi-steady state condition before the flow reaching steady state. Finally, 280 drawdown-time data from the hydraulic tomographic survey conducted at a field site corroborate our finding that the quasi-steady state condition likely would not take place in heterogeneous aquifers unless pumping tests last a long period. Research significance (1) Approximate quasi-steady and steady state conditions are defined for two- or three-dimensional flow induced by pumping in unbounded, equivalent homogeneous aquifers. (2) Analysis demonstrates effects of boundary condition, well screen interval, and heterogeneity of parameters on the

  18. Effect of subsoiling in fallow period on soil water storage and grain protein accumulation of dryland wheat and its regulatory effect by nitrogen application.

    Directory of Open Access Journals (Sweden)

    Min Sun

    Full Text Available To provide a new way to increase water storage and retention of dryland wheat, a field study was conducted at Wenxi experimental site of Shanxi Agricultural University. The effect of subsoiling in fallow period on soil water storage, accumulation of proline, and formation of grain protein after anthesis were determined. Our results showed that subsoiling in fallow period could increase water storage in the 0-300 cm soil at pre-sowing stage and at anthesis stage with low or medium N application, especially for the 60-160 cm soil. However, the proline content, glutamine synthetase (GS activity, glutamate dehydrogenase (GDH activity in flag leaves and grains were all decreased by subsoiling in fallow period. In addition, the content of albumin, gliadin, and total protein in grains were also decreased while globulin content, Glu/Gli, protein yield, and glutelin content were increased. With N application increasing, water storage of soil layers from 20 to 200 cm was decreased at anthesis stage. High N application resulted in the increment of proline content and GS activity in grains. Besides, correlation analysis showed that soil storage in 40-160 cm soil was negatively correlated with proline content in grains; proline content in grains was positively correlated with GS and GDH activity in flag leaves. Contents of albumin, globulin and total protein in grains were positively correlated with proline content in grains and GDH activity in flag leaves. In conclusion, subsoiling in fallow period, together with N application at 150 kg·hm(-2, was beneficial to increase the protein yield and Glu/Gli in grains which improve the quality of wheat.

  19. Flow and Thermal Performance of a Water-Cooled Periodic Transversal Elliptical Microchannel Heat Sink for Chip Cooling.

    Science.gov (United States)

    Wei, Bo; Yang, Mo; Wang, Zhiyun; Xu, Hongtao; Zhang, Yuwen

    2015-04-01

    Flow and thermal performance of transversal elliptical microchannels were investigated as a passive scheme to enhance the heat transfer performance of laminar fluid flow. The periodic transversal elliptical micro-channel is designed and its pressure drop and heat transfer characteristics in laminar flow are numerically investigated. Based on the comparison with a conventional straight micro- channel having rectangular cross section, it is found that periodic transversal elliptical microchannel not only has great potential to reduce pressure drop but also dramatically enhances heat transfer performance. In addition, when the Reynolds number equals to 192, the pressure drop of the transversal elliptical channel is 36.5% lower than that of the straight channel, while the average Nusselt number is 72.8% higher; this indicates that the overall thermal performance of the periodic transversal elliptical microchannel is superior to the conventional straight microchannel. It is suggested that such transversal elliptical microchannel are attractive candidates for cooling future electronic chips effectively with much lower pressure drop.

  20. Ground-water monitoring compliance projects for Hanford Site facilities: Progress Report for the Period July 1 to September 30, 1987

    Energy Technology Data Exchange (ETDEWEB)

    1987-11-01

    This report documents the progress of four Hanford Site ground-water monitoring projects for the period from July 1 to September 310, 1987. The four disposal facilities are the 300 Area Process Trenches, 183-H Solar Evaporation Basins, 200 Area Low-Level Burial Grounds, and Nonradioactive Dangerous Waste (NRDW) Landfill. This report is the fifth in a series of periodic status reports. During this reporting period, field activities consisted of completing repairs on five monitoring wells originally present around the 183-H Basins and completing construction of 25 monitoring wells around the 200 Area Burial Grounds. The 14 wells in the 200 East Area were completed by Kaiser Engineers Hanford (KEH) and the 11 wells in the 200 West Area were compelted by ONWEGO Well Drilling. The NRDW Landfill interim characterization report was submitted to the WDOE and the USEPA in August 1987. Analytical results for the 300 Area, 183-H, and the NRDW Landfill indicate no deviations from previously established trends. Results from the NRDW Land-fill indiate that the facility has no effect on the ground-water quality beneath the facility, except for the detection of coliform bacteria. A possible source of this contamination is the solid-waste lanfill (SWL) adjacent to the NRDW Landfill. Ground-water monitoring data for the NRDW and SWL will be evaluated together in the future. Aquifer testing was completed in the 25 new wells surrounding the 200 Area buiral grounds. 13 refs., 19 refs., 13 tabs.

  1. Comparison of water distribution mechanisms under two localized irrigation techniques (Drip Irrigation & Buried Diffuser) for one week irrigation period in a sandy soil of southeastern Tunisia

    Science.gov (United States)

    Gasmi, Ines; Kodešová, Radka; Mechergui, Mohamed; Nikodem, Antonín; Moussa, Mohamed

    2017-04-01

    The majority of agricultural ecosystems in the Mediterranean basin of northern Africa suffer from water shortage and positions these regions in a highly vulnerable to climate change. In arid regions of Tunisia and exactly in the Southeastern part, during each growing season, plant productivity in sandy-loamy soils is dramatically reduced by limited availability of soil water and nutrients. Thus, highly permeable soils are unable to retain adequate water and nutrient resource in the plant root zone. Moreover, the investments of supplemental irrigation and agricultural amendments of additional fertilization are not sustainable due to the leaching of water supplies and nutrients, which severely limit agricultural productivity. In addition, inadequate soil water distribution, costly irrigation and fertilization leads to negative responses to plant nutrients added to highly permeable soils. That's why we should use irrigation techniques with high water use efficiency. This paper focuses on the comparison between two localized irrigation techniques which are the Drip Irrigation (DI) and the Buried Diffuser (BD) that has the same flow rates (4 l/h). The BD is buried at 15 cm depths. Experimental data was obtained from Smar-Médenine located in South-East of Tunisia. The water distribution at the soil surface for BD is very important about 195 cm2 while for the DI is about 25.12 cm2. The HYDRUS 2D/3D model helped to evaluate the water distribution and compare the water balance obtained with those two irrigation techniques for one week irrigation period. There is a rapid kinetic which has a duration of 3 hours (irrigation time) and a slow kinetic which is the result of the water distribution in the soil, the plant uptake and the effect of climatic condition. There are two mechanisms that affect the two irrigation techniques: the water distribution and the position of irrigation system. As a result, irrigation with BD goes dipper in the soil. The transmission zone for this

  2. Persistence of DNA on clothes after exposure to water for different time periods-a study on bathtub, pond, and river.

    Science.gov (United States)

    Helmus, Janine; Zorell, Sarah; Bajanowski, Thomas; Poetsch, Micaela

    2018-01-01

    DNA traces on clothes of drowned bodies can provide important evidence for police investigations, especially in cases of suspected suicides or homicides. However, it is generally assumed that the water "erodes" a large part of the DNA depending especially on the exposure time. In forensic casework, DNA of suspects could be found frequently on clothes of drowned bodies after hours, sometimes days of exposure to water. This study was conducted to attempt a general statement about the conditions under which sufficient DNA remains can be expected for molecular genetic analysis. For this purpose, different scenarios were designed including DNA from three to five people, different types of waters (tap, pond, bathtub and river) for various time periods, with higher water pressure, different temperature, and soapy water (bathtub). Epithelial cells and blood cells were mounted on cotton cloths, and the DNA left after exposure was analyzed using the Powerplex® ESX17fast kit. In the indoor experiments, complete profiles could be seen even after 10 min rinsing of clothes under the tap and after 1 week in the bathtub. Outdoors, the results differed considerably between summer and winter as well as between pond and river. The longest exposure time still resulting in a complete profile was 2 weeks for a sample with skin cells in the pond during winter. In summer, the time period for erasing the bulk of DNA was 4 hours regarding epithelial samples and more than 1 day for blood samples in pond and river environments. All in all, the results demonstrate that DNA could still be recovered from clothes exposed to water for more than 1 week.

  3. The effect of water immersion delivery on the strength of pelvic floor muscle and pelvic floor disorders during postpartum period: An experimental study.

    Science.gov (United States)

    Zhao, Yun; Xiao, Mei; Tang, Fei; Tang, Wan; Yin, Heng; Sun, Guo-Qiang; Lin, Yin; Zhou, Yong; Luo, Yan; Li, Lu-Man; Tan, Zhi-Hua

    2017-10-01

    Water immersion delivery is a non-pharmacological approach to ease labor pain. This paper aims to investigate the effect of water immersion delivery on increasing strength of pelvic floor muscle (PFM) and relieving pelvic floor disorders (PFDs) during postpartum period. A total of 2749 vaginal-delivery primiparas in postpartum 6-8 weeks were selected as research objects. Based on the modes of delivery, 600 patients were assigned into water immersion delivery group, 2149 were assigned into conventional delivery group. The scales of PFM strength and pelvic organ prolapsed (POP) were determined by specially trained personnel using digital palpation, and the symptoms of stress urinary incontinence (SUI) were investigated by questionnaire survey. The weak PFM strength was improved by doing Kegel exercise at home for 6-8 weeks. We found that ①The rate of episiotomy in water immersion delivery group was 77.50% (465/600), which was lower than that in conventional delivery group (84.69%, 1820/2149) (P  .05); ④The rates of vaginal wall prolapsed and uterus prolapsed were 29.83% (179/600) and 2.83% (17/600) in water immersion delivery group and 30.95% (665/2149) and 4.37% (94/2149) in the conventional delivery group, wherein the intergroup difference was not significant (P > .05). ⑤After Kegel exercise, the strength of PFM was promoted (P < .01). Water immersion delivery has been proved to a beneficial alternative method for conventional delivery method. This delivery mode is associated with fewer episiotomy rate, and avoiding episiotomy is beneficial for maintaining PFM strength of women in postpartum 6-8 weeks. The strength of PFM during postpartum period can be improved by doing Kegel exercise at home.

  4. 81 FR 8742 - Announcement of Public Review Period for a Report of the Advisory Committee on Water Information...

    Science.gov (United States)

    2016-02-22

    ...Notice is hereby given of the availability for public review of the draft U.S. Geological Survey report, ``Guidelines for Determining Flood Flow Frequency'', commonly known as Bulletin 17B. This report was drafted under the auspices of the Hydrologic Frequency Analysis Work Group (HFAWG), which operates under the supervision of the Advisory Committee on Water Information's (ACWI) Subcommittee on Hydrology (SOH). Public review and comment is sought under the HFAWG Terms of Reference and the USGS peer review plan for the report (URL: http://www.usgs.gov/peer_review/docs/guidelines_for_determining_flood- flow_frequency.pdf). The ACWI was established under the authority of the Office of Management and Budget Memorandum 92-01 and the Federal Advisory Committee Act. The purpose of the ACWI is to provide a forum for water- information users and professionals to advise the Federal Government about activities and plans which may improve the effectiveness of meeting the Nation's water information needs. It has been 33 years since the last revision of Bulletin 17B in March 1982. At that time, it was recognized that continued investigation and improvements of flood frequency analysis techniques were needed. In fact, Bulletin 17B included a list of areas where additional research was recommended by the Work Group in 1982. The SOH's HFAWG has done extensive work during the last few years to update the Bulletin. The draft report resulting from that process is now available for public review and comment. The report may be accessed at http:// acwi.gov/hydrology/Frequency/b17c/index.html. A printed copy of the report may be obtained by contacting the U.S. Geological Survey, 12201 Sunrise Valley Drive, 417 National Center, Reston, Virginia 20192; (703) 648-6810.

  5. SBWR Model for Steady-State and Transient Analysis

    Directory of Open Access Journals (Sweden)

    Gilberto Espinosa-Paredes

    2008-01-01

    Full Text Available This paper presents a model of a simplified boiling water reactor (SBWR to analyze the steady-state and transient behavior. The SBWR model is based on approximations of lumped and distributed parameters to consider neutronics and natural circulation processes. The main components of the model are vessel dome, downcomer, lower plenum, core (channel and fuel, upper plenum, pressure, and level controls. Further consideration of the model is the natural circulation path in the internal circuit of the reactor, which governs the safety performance of the SBWR. To demonstrate the applicability of the model, the predictions were compared with plant data, manufacturer_s predictions, and RELAP5 under steady-state and transient conditions of a typical BWR. In steady-state conditions, the profiles of the main variables of the SBWR core such as superficial velocity, void fraction, temperatures, and convective heat transfer coefficient are presented and analyzed. The transient behavior of SBWR was analyzed during the closure of all main steam line isolation valves (MSIVs. Our results in this transient show that the cooling system due to natural circulation in the SBWR is around 70% of the rated core flow. According to the results shown here, one of the main conclusions of this work is that the simplified model could be very helpful in the licensing process.

  6. Numerical simulation of pool boiling for steady state and transient heating

    Energy Technology Data Exchange (ETDEWEB)

    He, Ying; Shoji, Masahiro; Maruyama, Shigeo

    1999-07-01

    It's believed that the macrolayer plays an important role in nucleate and transition boiling heat transfer at high heat flux. Many experiments have been carried out to support the macrolayer evaporation model, however, little has been conducted in the numerical simulation of boiling heat transfer. In this study, based on the macrolayer evaporation model of Maruyama et al. (1992), a numerical simulation of pool boiling for steady state was carried out. The key points of the simulation are: (1) It is modeled that the macrolayer containing vapor stems occupies the region immediately next to the wall and that the vapor stems are formed on the active cavity sites. (2) Not only does the evaporation occur at the vapor bubble-macrolayer interface, but also at the liquid-vapor stem interface. (3) The macrolayers form periodically. No liquid is supplied to the macrolayers during the hovering period. While the vapor mass departs from the surface, the macrolayers replenish immediately despite the complicity of the transition period between the departures of two vapor masses. The major results are: (1) The boiling curves of water and FC-72 (C{sub 6}F{sub 14}) were reasonably predicted. (2) The temporal variations in surface temperature for different boiling regimes were obtained. Secondly, the simulation of transient pool boiling was conducted. It was realized with following assumptions: (1) The macrolayer evaporation model can be extended to the transient pool boiling. The macrolayer forms cyclically and its thickness is determined by the surface heat flux when the vapor mass takes off. (2) One-dimensional transient heat conduction within the heater coupled with the macrolayer model was considered. Being employed explicit FDM, the instantaneous surface temperature can be obtained. Therefore, the instantaneous heat flux can be calculated by applying the surface temperature into the macrolayer model. (3) In the transition-boiling regime, the initial thickness of macrolayer

  7. Mesotubular-Structured Hybrid Membrane Nanocontainer for Periodical Monitoring, Separation, and Recovery of Cobalt Ions from Water.

    Science.gov (United States)

    El-Safty, Sherif A; Sakai, Masaru; Selim, Mahmoud M; Alhamid, Abdulaziz A

    2015-09-01

    Exposure to toxins can cause deleterious effects even at very low concentrations. We have developed an optical sensor, filter, and extractor (i.e., containerlike) in a nanoscale membrane (NSM) for the ultratrace sensing, separation, and recovery of Co(2+) ions from water. The design of the NSM is successfully controlled by dense decoration of a hydrophobic oil-hydrophilic receptor onto mesoscale tubular-structured silica nanochannels made of a hybrid anodic alumina membrane. The particular structure of the nanocontainer is ideal to control the multiple functions of the membrane, such as the optical detection/recognition, rejection/permeation, and recovery of Co(2+) species in a single step. A typical sensor, filter, and extractor assessment experiment was performed by using a benchtop contact time technique and a flow-through cell detector to allow for precise control of the optical detection and exclusive rejection of target ions and the permeation of nontarget metal ions in water. This nanocontainer membrane has great potential to meet the increasing needs of purification and separation of Co(2+) ions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Quantum-classical correspondence in steady states of nonadiabatic systems

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Mikiya; Yamashita, Koichi [Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656 (Japan); CREST, JST, Tokyo 113-8656 (Japan)

    2015-12-31

    We first present nonadiabatic path integral which is exact formulation of quantum dynamics in nonadiabatic systems. Then, by applying the stationary phase approximations to the nonadiabatic path integral, a semiclassical quantization condition, i.e., quantum-classical correspondence, for steady states of nonadiabatic systems is presented as a nonadiabatic trace formula. The present quantum-classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow degree of freedom, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels.

  9. STEADY DISBALANCE ASPECT IN POSITION GRADING SYSTEM

    Directory of Open Access Journals (Sweden)

    Potascheva Galina Anatol’evna

    2016-12-01

    Full Text Available This paper discusses the steady system disbalance from the standpoint of getting resources from the outside and Chaos (Entropy to Order transformation. It has been demonstrated that all live beings and the System reach for steadiness and effectiveness, which are essential properties and qualities of activities. Maintaining such properties and qualities in public life requires continuous life quality improvement of the population. One of the basic measures to ensure the life quality growth is distributing incomes using the Position Grading System.

  10. Short period forecasting of catchment-scale precipitation. Part II: a water-balance storm model for short-term rainfall and flood forecasting

    Directory of Open Access Journals (Sweden)

    V. A. Bell

    2000-01-01

    Full Text Available A simple two-dimensional rainfall model, based on advection and conservation of mass in a vertical cloud column, is investigated for use in short-term rainfall and flood forecasting at the catchment scale under UK conditions. The model is capable of assimilating weather radar, satellite infra-red and surface weather observations, together with forecasts from a mesoscale numerical weather prediction model, to obtain frequently updated forecasts of rainfall fields. Such data assimilation helps compensate for the simplified model dynamics and, taken together, provides a practical real-time forecasting scheme for catchment scale applications. Various ways are explored for using information from a numerical weather prediction model (16.8 km grid within the higher resolution model (5 km grid. A number of model variants is considered, ranging from simple persistence and advection methods used as a baseline, to different forms of the dynamic rainfall model. Model performance is assessed using data from the Wardon Hill radar in Dorset for two convective events, on 10 June 1993 and 16 July 1995, when thunderstorms occurred over southern Britain. The results show that (i a simple advection-type forecast may be improved upon by using multiscan radar data in place of data from the lowest scan, and (ii advected, steady-state predictions from the dynamic model, using 'inferred updraughts', provides the best performance overall. Updraught velocity is inferred at the forecast origin from the last two radar fields, using the mass-balance equation and associated data and is held constant over the forecast period. This inference model proves superior to the buoyancy parameterisation of updraught employed in the original formulation. A selection of the different rainfall forecasts is used as input to a catchment flow forecasting model, the IH PDM (Probability Distributed Moisture model, to assess their effect on flow forecast accuracy for the 135 km2 Brue catchment

  11. Fractal Analyses of Steady Infiltration and Terrain on an Undulating Agricultural Field

    Science.gov (United States)

    Fractal scaling behaviors have been observed in systems where interacting factors cause nested spatial structures. Surface water infiltration affects spatial patterns of soil water, nutrients, and plant development and crop yield. Here, we explored simple fractal scaling of quasi-steady infiltrati...

  12. Steady-State Creep of Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Alibai Iskakbayev

    2017-02-01

    Full Text Available This paper reports the experimental investigation of the steady-state creep process for fine-grained asphalt concrete at a temperature of 20 ± 2 °С and under stress from 0.055 to 0.311 MPa under direct tension and was found to occur at a constant rate. The experimental results also determined the start, the end point, and the duration of the steady-state creep process. The dependence of these factors, in addition to the steady-state creep rate and viscosity of the asphalt concrete on stress is satisfactorily described by a power function. Furthermore, it showed that stress has a great impact on the specific characteristics of asphalt concrete: stress variation by one order causes their variation by 3–4.5 orders. The described relations are formulated for the steady-state of asphalt concrete in a complex stressed condition. The dependence is determined between stress intensity and strain rate intensity.

  13. Relationship between weights of planktonic foraminifer shell and surface water CO sub(3) sup(=) concentration during the Holocene and Last Glacial Period

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Naidu, P.D.; Govil, P.; Godad, S.

    it influences the dissolved inorganic carbon (DIC) species; CO 2 (aq), H 2 CO 3 , HCO 3 - and CO 3 = (Broecker and Peng, 1982). The increased dissolution of CO 2 consequently decreases the pH and carbonate ion concentration [CO 3 = ] of surface... and deep waters. Records from Antarctic ice cores indicate that the concentration of CO 2 in the atmosphere has varied in step with the waxing and waning of ice ages, fluctuating between 180ppmv to 280ppmv during glacial and interglacial time periods...

  14. Stability analysis of a partitioned iterative method for steady free surface flow

    Science.gov (United States)

    Demeester, Toon; Degroote, Joris; Vierendeels, Jan

    2018-02-01

    This note considers the steady free surface (FS) flow problem as encountered in the paper by van Brummelen et al. [1]. In that paper, steady flow of water in a two-dimensional slice of an infinitely wide open channel with a particular bottom wall is calculated as the first step in the development of a 3D surface fitting method for steady flow around ships. In these water-air flows, the influence of air is usually negligible due to the large difference in density. Contrary to surface capturing methods which are typically multiphase techniques (such as the volume-of-fluid method), fitting methods usually consider only the water phase. The latter approach requires appropriate FS boundary conditions. The dynamic boundary condition (DBC) used here assumes that the pressure is constant (atmospheric) at the FS and the shear stresses are zero. The kinematic boundary condition (KBC) states that the FS is impermeable.

  15. Qualidade da água em diferentes estádios de desenvolvimento do arroz irrigado Quality of water in different periods of growth of flooded rice

    Directory of Open Access Journals (Sweden)

    Joseline Molozzi

    2006-09-01

    Full Text Available Este trabalho teve como objetivo avaliar a qualidade da água utilizada para a rizicultura, em diferentes estádios de desenvolvimento da planta, no sistema de plantio pré-germinado. Foram analisadas as águas de irrigação e de drenagem no processo de cultivo. Foram escolhidas três áreas de amostragens, localizadas no Município de Gaspar, SC, que apresentam técnicas de cultivo semelhantes. A água utilizada para irrigação é retirada de um curso de água e devolvida após o uso no quarteirão, para o mesmo curso. Neste sistema não existem aportes de poluentes externos intermediários. Para avaliar a qualidade da água, foi utilizado o Índice de Qualidade de Água de Bascarán (IQAb. De acordo com os resultados, a água utilizada para irrigação apresenta qualidade imprópria (IQAb 40-50. A água de drenagem foi classificada, de modo geral, como desagradável (IQAb 30-40. Os parâmetros que mais influenciaram a diminuição do IQAb na água de drenagem foram a turbidez, fosfatos e DQO. Constatou-se que a fase de preparo do solo é a que provoca maior degradação da qualidade da água, na cultura orizícola.The objective of this study was to evaluate the quality of the water used for rice irrigation, considering different periods of the plants growth, using the pre-germinated seeds planting technique. Irrigation and drainage water were analyzed during the process of tillage. Three sites of sampling located around the City of Gaspar SC, Brazil were chosen. All three sites presented similar techniques of tillage. The water used for the irrigation was collected from a watercourse and returned after it passed through the tillage. In this system there are no external or intermediary pollutant conductors. To evaluate the quality of water it was used the Quality of Water Index from Bascarán (IQAb. The results demonstrate that the water used for irrigation, enters in the tillage area with an improper quality (IQAb 40-50. Drainage water was

  16. Impact of S fertilizers on pore-water Cu dynamics and transformation in a contaminated paddy soil with various flooding periods.

    Science.gov (United States)

    Yang, Jianjun; Zhu, Shenhai; Zheng, Cuiqing; Sun, Lijuan; Liu, Jin; Shi, Jiyan

    2015-04-09

    Impact of S fertilization on Cu mobility and transformation in contaminated paddy soils has been little reported. In this study, we investigated the dynamics and transformation of dissolved and colloidal Cu in the pore water of a contaminated paddy soil after applying ammonium sulphate (AS) and sulfur coated urea (SCU) with various flooding periods (1, 7 and 60 days). Compared to the control soil, the AS-treated soil released more colloidal and dissolved Cu over the entire flooding period, while the SCU-treated soil had lower colloidal Cu after 7-day flooding but higher colloidal and dissolved Cu after 60-day flooding. Microscopic X-ray fluorescence (μ-XRF) analysis found a close relationship between Fe and Cu distribution on soil colloids after 60-day flooding, implying the formation of colloidal Fe/Cu sulphide coprecipitates. Cu K-edge X-ray absorption near-edge structure (XANES) spectroscopy directly revealed the transformation of outer-sphere complexed Cu(II) species to Cu(II) sulphide and reduced Cu2O in the colloids of S-treated soils after 60-day flooding. These results demonstrated the great influence of S fertilization on pore-water Cu mobility by forming Cu sulphide under flooding conditions, which facilitated our understanding and control of Cu loss in contaminated paddy soils under S fertilization. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Comparison of different combined treatment processes to address the source water with high concentration of natural organic matter during snowmelt period.

    Science.gov (United States)

    Lin, Pengfei; Zhang, Xiaojian; Wang, Jun; Zeng, Yani; Liu, Shuming; Chen, Chao

    2015-01-01

    The source water in one forest region of the Northeast China had very high natural organic matter (NOM) concentration and heavy color during snowmelt period. The efficiency of five combined treatment processes was compared to address the high concentration of NOM and the mechanisms were also analyzed. Conventional treatment can hardly remove dissolved organic carbon (DOC) in the source water. KMnO4 pre-oxidization could improve the DOC removal to 22.0%. Post activated carbon adsorption improved the DOC removal of conventional treatment to 28.8%. The non-sufficient NOM removal could be attributed to the dominance of large molecular weight organic matters in raw water, which cannot be adsorbed by the micropore upon activated carbon. O3+activated carbon treatment are another available technology for eliminating the color and UV254 in water. However, its performance of DOC removal was only 36.4%, which could not satisfy the requirement for organic matter. The limited ozone dosage is not sufficient to mineralize the high concentration of NOM. Magnetic ion-exchange resin combined with conventional treatment could remove 96.2% of color, 96.0% of UV254 and 87.1% of DOC, enabling effluents to meet the drinking water quality standard. The high removal efficiency could be explained by the negative charge on the surface of NOM which benefits the static adsorption of NOM on the anion exchange resin. The results indicated that magnetic ion-exchange resin combined with conventional treatment is the best available technology to remove high concentration of NOM. Copyright © 2014. Published by Elsevier B.V.

  18. Steady laminar flow of fractal fluids

    Science.gov (United States)

    Balankin, Alexander S.; Mena, Baltasar; Susarrey, Orlando; Samayoa, Didier

    2017-02-01

    We study laminar flow of a fractal fluid in a cylindrical tube. A flow of the fractal fluid is mapped into a homogeneous flow in a fractional dimensional space with metric induced by the fractal topology. The equations of motion for an incompressible Stokes flow of the Newtonian fractal fluid are derived. It is found that the radial distribution for the velocity in a steady Poiseuille flow of a fractal fluid is governed by the fractal metric of the flow, whereas the pressure distribution along the flow direction depends on the fractal topology of flow, as well as on the fractal metric. The radial distribution of the fractal fluid velocity in a steady Couette flow between two concentric cylinders is also derived.

  19. Development of steady state magnetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Shigemitsu; Nakayama, Takahide [Hitachi Ltd., Tokyo (Japan); Nagashima, Akira; Kasai, Satoshi

    1998-12-01

    A prototype of new mechanical sensor based on the steady state electromagnetic force (J x B force) measurement has been developed and tested. The mechanical force sensor is a new type of the magnetic sensor which is available for frequencies smaller than 0.1 Hz. The prototype of the mechanical sensor has been examined, and the following results were obtained; (1) A signal was proportional to simulated force in the load cell tests. (2) A signal drift concerning the temperature was reproducible over the range of the ITER environment. (3) A signal was proportional to the magnetic field in the steady state magnetic field measurement tests. (4) A load cell linearity error did not increase significantly after irradiation of 7.2 x 10{sup 6} Gy. These results indicate that the mechanical sensor will provide the practical feasibility in the long time magnetic field measurement. (author)

  20. Steady state compact toroidal plasma production

    Science.gov (United States)

    Turner, William C.

    1986-01-01

    Apparatus and method for maintaining steady state compact toroidal plasmas. A compact toroidal plasma is formed by a magnetized coaxial plasma gun and held in close proximity to the gun electrodes by applied magnetic fields or magnetic fields produced by image currents in conducting walls. Voltage supply means maintains a constant potential across the electrodes producing an increasing magnetic helicity which drives the plasma away from a minimum energy state. The plasma globally relaxes to a new minimum energy state, conserving helicity according to Taylor's relaxation hypothesis, and injecting net helicity into the core of the compact toroidal plasma. Controlling the voltage so as to inject net helicity at a predetermined rate based on dissipative processes maintains or increases the compact toroidal plasma in a time averaged steady state mode.

  1. Summary report of responses of key resources to the 2000 Low Steady Summer Flow experiment, along the Colorado River downstream from Glen Canyon Dam, Arizona

    Science.gov (United States)

    Ralston, Barbara E.

    2011-01-01

    In the spring and summer of 2000, a series of steady discharges of water from Glen Canyon Dam on the Colorado River were used to evaluate the effects of aquatic habitat stability and water temperatures on native fish growth and survival, with a special focus on the endangered humpback chub (Gila cypha), downstream from the dam in Grand Canyon. The steady releases were bracketed by peak powerplant releases in late-May and early-September. The duration and volume of releases from the dam varied between spring and summer. The intent of the experimental hydrograph was to mimic predam river discharge patterns by including a high, steady discharge in the spring and a low, steady discharge in the summer. The hydrologic experiment was called the Low Steady Summer Flow (LSSF) experiment because steady discharges of 226 m3/s dominated the hydrograph for 4 months from June through September 2000. The experimental hydrograph was developed in response to one of the U.S. Fish and Wildlife Service's Recommended and Prudent Alternatives (RPA) in its Biological Opinion of the Operation of Glen Canyon Dam Final Environmental Impact Statement. The RPA focused on the hypothesis that seasonally adjusted steady flows were dam operations that might benefit humpback chub more than the Record of Decision operations, known as Modified Low Fluctuating Flow (MLFF) operations. Condensed timelines between planning and implementation (2 months) of the experiment and the time required for logistics, purchasing, and contracting resulted in limited data collection during the high-release part of the experiment that occurred in spring. The LSSF experiment is the longest planned hydrograph that departed from the MLFF operations since Record of Decision operations began in 1996. As part of the experiment, several studies focused on the responses of physical properties related to environments that young-of-year (YOY) native fish might occupy (for example, measuring mainstem and shoreline water

  2. Steady laminar flow of fractal fluids

    Energy Technology Data Exchange (ETDEWEB)

    Balankin, Alexander S., E-mail: abalankin@ipn.mx [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico); Mena, Baltasar [Laboratorio de Ingeniería y Procesos Costeros, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Sisal, Yucatán, 97355 (Mexico); Susarrey, Orlando; Samayoa, Didier [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico)

    2017-02-12

    We study laminar flow of a fractal fluid in a cylindrical tube. A flow of the fractal fluid is mapped into a homogeneous flow in a fractional dimensional space with metric induced by the fractal topology. The equations of motion for an incompressible Stokes flow of the Newtonian fractal fluid are derived. It is found that the radial distribution for the velocity in a steady Poiseuille flow of a fractal fluid is governed by the fractal metric of the flow, whereas the pressure distribution along the flow direction depends on the fractal topology of flow, as well as on the fractal metric. The radial distribution of the fractal fluid velocity in a steady Couette flow between two concentric cylinders is also derived. - Highlights: • Equations of Stokes flow of Newtonian fractal fluid are derived. • Pressure distribution in the Newtonian fractal fluid is derived. • Velocity distribution in Poiseuille flow of fractal fluid is found. • Velocity distribution in a steady Couette flow is established.

  3. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  4. Resource Conservation and Recovery Act ground-water monitoring projects for Hanford facilities: Progress Report for the Period April 1 to June 30, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.M.; Bates, D.J.; Lundgren, R.E.

    1989-09-01

    This report describes the progress of 13 Hanford ground-water monitoring projects for the period April 1 to June 30, 1989. These projects are for the 300 area process trenches (300 area), 183-H solar evaporation basins (100-H area), 200 areas low-level burial grounds, nonradioactive dangerous waste landfill (southeast of the 200 areas), 1301-N liquid waste disposal facility (100-N area), 1324-N surface impoundment and 1324-NA percolation pond (100-N area), 1325-N liquid waste disposal facility (100-N area), 216-A-10 crib (200-east area), 216-A-29 ditch (200-east area), 216-A-36B crib (200-east area), 216-B-36B crib (200-east area), 216-B-3 pond (east of the 200-east area), 2101-M pond (200-east area), grout treatment facility (200-east area).

  5. Shapes and speeds of steady forced premixed flames.

    Science.gov (United States)

    Joulin, Guy; Denet, Bruno

    2014-06-01

    Steady premixed flames subjected to space-periodic steady forcing are studied via inhomogeneous Michelson-Sivashinsky (MS) and then Burgers equations. For both, the flame slope is posited to comprise contributions from complex poles to locate, and from a base-slope profile chosen in three classes (pairs of cotangents, single-sine functions or sums thereof). Base-slope-dependent equations for the pole locations, along with formal expressions for the wrinkling-induced flame-speed increment and the forcing function, are obtained on excluding movable singularities from the latter. Besides exact few-pole cases, integral equations that rule the pole density for large wrinkles are solved analytically. Closed-form flame-slope and forcing-function profiles ensue, along with flame-speed increment vs forcing-intensity curves; numerical checks are provided. The Darrieus-Landau instability mechanism allows MS flame speeds to initially grow with forcing intensity much faster than those of identically forced Burgers fronts; only the fractional difference in speed increments slowly decays at intense forcing, which numerical (spectral) timewise integrations also confirm. Generalizations and open problems are evoked.

  6. Control of VR-7 Dynamic Stall by Strong Steady Blowing

    Science.gov (United States)

    Weaver, D.; McAlister, K. W.; Tso, J.

    2004-01-01

    An experiment was performed in a water tunnel on a Boeing-Vertol VR-7 airfoil to study the effects of tangential blowing over the upper surface. Blowing was applied at the quarter-chord location during sinusoidal pitching oscillations described by alpha = alpha(sub m) + 10 deg sin omega t. Results were obtained for a Reynolds number of 1 x 10(exp 5), mean angles of 10 and 15 deg, reduced frequencies ranging from 0.005 to 0.15, and blowing rates from C(sub mu) = 0.16 to 0.66. Unsteady lift, drag, and pitching moment loads are reported, along with fluorescent-dye flow visualizations. Strong steady blowing was found to prevent the bursting of the leading-edge separation bubble at several test points. When this occurred, the lift was increased significantly, stall was averted, and the shape of the moment response showed a positive damping in pitch. In almost all cases, steady blowing reduced the hysteresis amplitudes present in the loads, but the benefits diminished as the reduced frequency and mean angle of oscillation increased. A limited number of pulsed blowing cases indicated that for low blowing rates, the greatest gains were achieved at F(sup +) = 0.9.

  7. A novel approach of periodate oxidation coupled with HPLC-FLD for the quantitative determination of 3-chloro-1,2-propanediol in water and vegetable oil.

    Science.gov (United States)

    Hu, Zhixiong; Cheng, Peng; Guo, Mingli; Zhang, Weinong; Qi, Yutang

    2013-07-10

    A novel approach of periodate oxidation coupled with high-performance liquid chromatography (HPLC)-fluorescence detection (FLD) for the quantitative determination of 3-chloro-1,2-propanediol (3-MCPD) has been established. The essence of this approach lies in the production of chloroacetaldehyde by the oxidization cleavage of 3-MCPD with sodium periodate and the HPLC analysis of chloroacetaldehyde monitored by an FLD detector after fluorescence derivatization with adenine. The experimental parameters relating to the efficiency of the derivative reaction such as concentration of adenine, chloroacetaldehyde reaction temperature, and time were studied. Under the optimized conditions, the proposed method can provide high sensitivity, good linearity (r(2) = 0.999), and repeatability (percent relative standard deviations between 2.57% and 3.44%), the limits of detection and quantification were 0.36 and 1.20 ng/mL, respectively, and the recoveries obtained for water samples were in the range 93.39-97.39%. This method has been successfully applied to the analysis of real water samples. Also this method has been successfully used for the analysis of vegetable oil samples after pretreatment with liquid-liquid extraction; the recoveries obtained by a spiking experiment with soybean oil ranged from 96.27% to 102.42%. In comparison with gas chromatography or gas chromatography-mass spectrometry, the proposed method can provide the advantages of simple instrumental requirement, easy operation, low cost, and high efficiency, thus making this approach another good choice for the sensitive determination of 3-MCPD.

  8. Topological clustering as a tool for planning water quality monitoring in water distribution networks

    DEFF Research Database (Denmark)

    Kirstein, Jonas Kjeld; Albrechtsen, Hans-Jørgen; Rygaard, Martin

    2015-01-01

    ) identify steady clusters for a part of the network where an actual contamination has occurred; (2) analyze this event by the use of mesh diagrams; and (3) analyze the use of mesh diagrams as a decision support tool for planning water quality monitoring. Initially, the network model was divided...... into strongly and weakly connected clusters for selected time periods and mesh diagrams were used for analysing cluster connections in the Nørrebro district. Here, areas of particular interest for water quality monitoring were identified by including user-information about consumption rates and consumers...... particular sensitive towards water quality deterioration. The analysis revealed sampling locations within steady clusters, which increased samples' comparability over time. Furthermore, the method provided a simplified overview of water movement in complex distribution networks, and could assist...

  9. The effect of differences rainfall data duration and time period in the assessment of rainwater harvesting system performance for domestic water use

    Science.gov (United States)

    Juliana, Imroatul C.; Kusuma, M. Syahril Badri; Cahyono, M.; Martokusumo, Widjaja; Kuntoro, Arno Adi

    2017-11-01

    One of the attempts to tackle the problem in water resources is to exploit the potential of rainwater volume with rainwater harvesting (RWH) system. A number of rainfall data required for analyzing the RWH system performance. In contrast, the availability of rainfall data is occasionally difficult to obtain. The main objective of this study is to investigate the effect of difference rainfall data duration and time period to assess the RWH system performance. An analysis was conducted on the rainfall data based on rainfall data duration and time period. The analysis was performed considering 15, 5, 3, 2 years, average year, wet year, and dry year for Palembang city in South Sumatera. The RWH system performance is calculated based on the concept of yield before spillage algorithm. A number of scenarios were conducted by varying the tank capacity, roof area, and the rainwater demand. It was observed that the use of data with a smaller duration provides a significant difference, especially for high rainwater demand. In addition, the use of daily rainfall data would describe th e behavior of the system more thoroughly. As for time step, the use of monthly rainfall data is only sufficient for low rainwater demand and bigger tank capacity.

  10. Variations in water level for Lake Turkana in the past 8500 years near Mt. Porr, Kenya and the transition from the African Humid Period to Holocene aridity

    Science.gov (United States)

    Forman, Steven L.; Wright, David K.; Bloszies, Christopher

    2014-08-01

    A stratigraphic and geomorphic study of relict beaches up to 80 m above current water level of Lake Turkana reveal four major lake level fluctuations of >50 m between ca 8.5 and 4.5 ka during the transition from the African Humid Period to Holocene aridity. We hypothesize that high stands of Lake Turkana reflect complex hydrological processes with variability in Atlantic and Indian Ocean-derived moisture into East Africa, ultimately linked to changes in sea surface temperatures (SSTs). Lake level rise was also amplified regionally by increased precipitation causing overflow from the adjacent Suguta and Chew Bahir basins, particularly during high stands at ca >8.5 ka and at 6.4 ka. The timing of transgressive and regressive events is constrained by 14C dating of carefully selected lacustrine mollusks, incorporation of previous shell ages with sufficient elevational control, and OSL dating of quartz grains from littoral and sublittoral deposits by a multiple aliquot regeneration (MAR) approach. There was a high water level up to at least 70 m at >8.5 ka that probably reached the spillover limit ˜100 m. A brief (lake level by 4.6 ka. Evidence from relict Porr strand plain indicate that lake level was probably below 20 m since ca 4.5 ka, though there were two noticeable high stands up to 12-20 m at ca 830 years ago and <100 years, the latter age is consistent with the historic record.

  11. Effect of the addition of organic acids in drinking water or feed during part of the finishing period on the prevalence of Salmonella in finishing pigs.

    Science.gov (United States)

    Argüello, Héctor; Carvajal, Ana; Costillas, Sara; Rubio, Pedro

    2013-10-01

    Pork is a major cause of foodborne salmonellosis. Consequently, effective measures that could reduce the prevalence of Salmonella at the farm are of interest. In the present study, three field trials were performed to evaluate the effect of strategic administration of organic acids, at concentrations estimated by economic criteria, on the Salmonella prevalence in finishing pigs. Pigs received either a mixture of acids (lactic, formic, propionic, and acetic) added to their drinking water at a concentration of 0.035% (trial A), or a basal diet containing 0.5% potassium-diformate, KH(COOH)₂, (trials B and C), during the last 6-7 weeks of the finishing period. Fecal Salmonella shedding and seroprevalence were monitored in the animals at four time points during the study. Mesenteric lymph nodes and cecal contents were collected from a subset of animals at the slaughterhouse and cultured for Salmonella. At the end of the finishing period in all three trials, the percentage of seropositive pigs was higher in the control group than in the experimental group, regardless of which cutoff value was used in the enzyme-linked immunosorbent assay (ELISA) assay. The frequency of fecal shedding was lower also in the treated pig groups from the trials A and B at the end of the finishing period. The results from the samples collected at the slaughterhouse did not yield differences between groups in trials A and B. However, Salmonella isolation was less frequent in the mesenteric lymph nodes from the experimental pigs in trial C. The seroprevalence reductions, together with some promising results in the reduction of shedding, support the idea that this intervention is a useful strategy to reduce Salmonella prevalence at the farm.

  12. Steady state modeling of desiccant wheels

    DEFF Research Database (Denmark)

    Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin Ryhl

    2014-01-01

    Desiccant wheels are rotary desiccant dehumidifiers used in air conditioning and drying applications. The modeling of simultaneous heat and mass transfer in these components is crucial for estimating their performances, as well as for simulating and optimizing their implementation in complete...... systems. A steady state two-dimensional model is formulated and implemented aiming to obtain good accuracy and short computational times. Comparison with experimental data from the literature shows that the model reproduces the physical behavior of desiccant wheels. Mass diffusion in the desiccant should...

  13. Exploiting multicompartment effects in triple-echo steady-state T2 mapping for fat fraction quantification.

    Science.gov (United States)

    Liu, Dian; Steingoetter, Andreas; Curcic, Jelena; Kozerke, Sebastian

    2018-01-01

    To investigate and exploit the effect of intravoxel off-resonance compartments in the triple-echo steady-state (TESS) sequence without fat suppression for T2 mapping and to leverage the results for fat fraction quantification. In multicompartment tissue, where at least one compartment is excited off-resonance, the total signal exhibits periodic modulations as a function of echo time (TE). Simulated multicompartment TESS signals were synthesized at various TEs. Fat emulsion phantoms were prepared and scanned at the same TE combinations using TESS. In vivo knee data were obtained with TESS to validate the simulations. The multicompartment effect was exploited for fat fraction quantification in the stomach by acquiring TESS signals at two TE combinations. Simulated and measured multicompartment signal intensities were in good agreement. Multicompartment effects caused erroneous T2 offsets, even at low water-fat ratios. The choice of TE caused T2 variations of as much as 28% in cartilage. The feasibility of fat fraction quantification to monitor the decrease of fat content in the stomach during digestion is demonstrated. Intravoxel off-resonance compartments are a confounding factor for T2 quantification using TESS, causing errors that are dependent on the TE. At the same time, off-resonance effects may allow for efficient fat fraction mapping using steady-state imaging. Magn Reson Med 79:423-429, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  14. FOREX Trades: Can the Takens Algorithm Help to Obtain Steady Profit at Investment Reallocations?

    Science.gov (United States)

    Petrov, V. Yu.; Tribelsky, M. I.

    2015-12-01

    We report our preliminary results of application of the Takens algorithm to build a FOREX trade strategy, resulting in a steady long-time gain for a trader. The actual historical rates for pair EUR vs. USD are used. The values of various parameters of the problem including the "stop loss" and "take profit" thresholds are optimized to provide the maximal gain during the training period. Then, these values are employed for trades. We have succeeded to get the steady gain, if the spread is neglected. It proves that the FOREX market is predictable.

  15. Historiske perioder

    DEFF Research Database (Denmark)

    2017-01-01

    For at forstå fortiden og fortællingerne om den, må vi skabe en form for orden og systematik. Her spiller inddelingen af fortiden i historiske perioder en afgørende rolle – og historiske perioder er da også et kompetencemål efter 6. klasse. Videoen diskuterer forskellige principper...... for periodisering. Kronologi og sammenhænge hænger naturligt sammen med historiske perioder. Videoen handler også om forståelser og brug af synkrone og diakrone sammenhænge i faget....

  16. Temporal filters for isolating steady photospheric flows

    Science.gov (United States)

    Hathaway, David H.

    A variety of temporal filters are tested on artificial data with 60 and 75 s sampling intervals to determine their accuracy in separating the nearly-steady photospheric flows from the p-mode oscillations in Doppler velocity data. Longer temporal averages are better at reducing the residual signal due to p-modes but they introduce additional errors from the rotation of the supergranule pattern across the solar disk. Unweighted filters (boxcar averages) leave residual rms errors of about 6 m/s from the p-modes after 60 min of averaging. Weighted filters, with nearly Gaussian shapes, leave similar residual errors after only 20 min of averaging and introduce smaller errors from the rotation of the supergranule pattern. The best filters found are weighted filters that use data separated by 150 or 120 s so that the p-modes are sampled at opposite phases.

  17. Asymptotic stability of steady compressible fluids

    CERN Document Server

    Padula, Mariarosaria

    2011-01-01

    This volume introduces a systematic approach to the solution of some mathematical problems that arise in the study of the hyperbolic-parabolic systems of equations that govern the motions of thermodynamic fluids. It is intended for a wide audience of theoretical and applied mathematicians with an interest in compressible flow, capillarity theory, and control theory. The focus is particularly on recent results concerning nonlinear asymptotic stability, which are independent of assumptions about the smallness of the initial data. Of particular interest is the loss of control that sometimes results when steady flows of compressible fluids are upset by large disturbances. The main ideas are illustrated in the context of three different physical problems: (i) A barotropic viscous gas in a fixed domain with compact boundary. The domain may be either an exterior domain or a bounded domain, and the boundary may be either impermeable or porous. (ii) An isothermal viscous gas in a domain with free boundaries. (iii) A h...

  18. Magnetic sensor for steady state tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Neyatani, Yuzuru; Mori, Katsuharu; Oguri, Shigeru; Kikuchi, Mitsuru [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-06-01

    A new type of magnetic sensor has been developed for the measurement of steady state magnetic fields without DC-drift such as integration circuit. The electromagnetic force induced to the current which leads to the sensor was used for the measurement. For the high frequency component which exceeds higher than the vibration frequency of sensor, pick-up coil was used through the high pass filter. From the results using tokamak discharges, this sensor can measure the magnetic field in the tokamak discharge. During {approx}2 hours measurement, no DC drift was observed. The sensor can respond {approx}10ms of fast change of magnetic field during disruptions. We confirm the extension of measured range to control the current which leads to the sensor. (author).

  19. Rapid multicomponent relaxometry in steady state with correction of magnetization transfer effects.

    Science.gov (United States)

    Liu, Fang; Block, Walter F; Kijowski, Richard; Samsonov, Alexey

    2016-04-01

    To study the effects of magnetization transfer (MT) on multicomponent T2 parameters obtained using mcDESPOT in macromolecule-rich tissues and to propose a new method called mcRISE to correct MT-induced biases. The two-pool mcDESPOT model was modified by the addition of an exchanging macromolecule proton pool to model the MT effect in cartilage. The mcRISE acquisition scheme was developed to provide sensitivity to all pools. An incremental fitting was applied to estimate MT and relaxometry parameters with minimized coupling. The interaction between MT and relaxometry parameters, efficacy of MT correction, and feasibility of mcRISE in vivo were investigated in simulations and in healthy volunteers. The MT effect caused significant errors in multicomponent T1/T2 values and in fast-relaxing water fraction fF , which is consistent with previous experimental observations. fF increased significantly with macromolecule content if MT was ignored. mcRISE resulted in a multifold reduction of MT biases and yielded decoupled multicomponent T1/T2 relaxometry and quantitative MT parameters. mcRISE is an efficient approach for correcting MT biases in multicomponent relaxometry based on steady state sequences. Improved specificity of mcRISE may help to elucidate the sources of the previously described high sensitivity of noncorrected mcDESPOT parameters to disease-related changes in cartilage and the brain. © 2015 Wiley Periodicals, Inc.

  20. Progress towards Steady State on NSTX

    Energy Technology Data Exchange (ETDEWEB)

    D.A. Gates; C. Kessel; J. Menard; G. Taylor; J.R. Wilson; plus 94 co-authors

    2005-01-24

    In order to reduce recirculating power fraction to acceptable levels, the spherical torus concept relies on the simultaneous achievement of high toroidal {beta} and high bootstrap fraction in steady state. In the last year, as a result of plasma control system improvements, the achievable plasma elongation on the National Spherical Torus Experiment (NSTX) has been raised from {kappa} {approx} 2.1 to {kappa} {approx} 2.6--approximately a 25% increase. This increase in elongation has lead to a doubling increase in the toroidal {beta} for long-pulse discharges. The increase in {beta} is associated with an increase in plasma current at nearly fixed poloidal {beta}, which enables higher {beta}{sub t} with nearly constant bootstrap fraction. As a result, for the first time in a spherical torus, a discharge with a plasma current of 1 MA has been sustained for 1 second. Data is presented from NSTX correlating the increase in performance with increased plasma shaping capability. In addition to improved shaping, H-modes induced during the current ramp phase of the plasma discharge have been used to reduce flux consumption during and to delay the onset of MHD instabilities. A modeled integrated scenario, which has 100% non-inductive current drive with very high toroidal {beta}, will also be presented. The NSTX poloidal field coils are currently being modified to produce the plasma shape which is required for this scenario, which requires high triangularity ({delta} {approx} 0.8) at elevated elongation ({kappa} {approx} 2.5). The other main requirement for steady state on NSTX is the ability to drive a fraction of the total plasma current with radio-frequency waves. The results of High Harmonic Fast Wave heating and current drive studies as well as electron Bernstein Wave emission studies will be presented.

  1. Absence of Effect of Rufloxacin on Theophylline Pharmacokinetics in Steady State†

    Science.gov (United States)

    Kinzig-Schippers, Martina; Fuhr, Uwe; Cesana, Marina; Müller, Carola; Staib, A. Horst; Rietbrock, S.; Sörgel, Fritz

    1998-01-01

    Several quinolone antibacterial agents are known to inhibit the metabolism of theophylline, with the potential to cause adverse events due to raised theophylline concentrations during coadministration. A randomized crossover study was therefore conducted with 12 healthy male volunteers (ages, 23 to 34 years; body weight, 64 to 101 kg) to evaluate a possible interaction between rufloxacin and theophylline. Both drugs were administered at steady state. Following the administration of an oral loading dose of 400 mg on day 1, rufloxacin was given orally at 200 mg once daily on days 2 to 7 during one period only. During both periods, 146 mg of theophylline was administered orally twice daily for 3 days (which were days 4 to 6 of the rufloxacin coadministration period) and intravenously once the next morning to test for an interaction. Theophylline and rufloxacin concentrations were measured by reversed-phase high-pressure liquid chromatography, the pharmacokinetics of theophylline at steady state following administration of the last dose were calculated by compartment-model-independent methods. To compare the treatments, analysis of variance-based point estimates and 90% confidence intervals (given in parentheses) were calculated for the mean ratios of the pharmacokinetic parameters from the test (rufloxacin coadministration) over those from the reference (theophylline without rufloxacin) period. These were as follows: maximum concentration at steady state, 1.01 (0.96 to 1.07); area under the concentration-time curve from 0 to 12 h, 0.98 (0.94 to 1.02); half-life, 0.99 (0.95 to 1.03); total clearance at steady state, 1.02 (0.99 to 1.06); and volume of distribution in the elimination phase, 1.01 (0.97 to 1.05). In conclusion, rufloxacin did not affect theophylline pharmacokinetics at steady state. Therefore, therapeutic coadministration of rufloxacin and theophylline is not expected to cause an increased incidence of theophylline-related adverse events. PMID:9736563

  2. Solving the Bloch equation with periodic excitation using harmonic balancing: application to Rabi modulated excitation.

    Science.gov (United States)

    Tahayori, Bahman; Johnston, Leigh A; Layton, Kelvin J; Farrell, Peter M; Mareels, Iven M Y

    2015-10-01

    In waveform design for magnetic resonance applications, periodic continuous-wave excitation offers potential advantages that remain largely unexplored because of a lack of understanding of the Bloch equation with periodic continuous-wave excitations. Using harmonic balancing techniques the steady state solutions of the Bloch equation with periodic excitation can be effectively solved. Moreover, the convergence speed of the proposed series approximation is such that a few terms in the series expansion suffice to obtain a very accurate description of the steady state solution. The accuracy of the proposed analytic approximate series solution is verified using both a simulation study as well as experimental data derived from a spherical phantom with doped water under continuous-wave excitation. Typically a five term series suffices to achieve a relative error of less than one percent, allowing for a very effective and efficient analytical design process. The opportunities for Rabi frequency modulated continuous-wave form excitation are then explored, based on a comparison with steady state free precession pulse sequences.

  3. PERIODIC BEHAVIORS

    NARCIS (Netherlands)

    Napp, Diego; Put, Marius van der; Shankar, Shiva

    2010-01-01

    This paper studies behaviors that are defined on a torus, or equivalently, behaviors defined in spaces of periodic functions, and establishes their basic properties analogous to classical results of Malgrange, Palamodov, Oberst et al. for behaviors on R(n). These properties-in particular the

  4. CFD/Quasi-Steady Coupled Trim Analysis of Diptera-type Flapping Wing MAV in Steady Flight

    Science.gov (United States)

    Badrya, Camli

    The nuances in flapping wing aerodynamics are not yet fully understood to the extent where concepts can be translated to practical designs. Trimmed flight is a fundamental concept for aircraft in general. It describes the flight condition when there are no accelerations on the vehicle. From an engineering perspective, trim estimation is essential for performance analysis and flapping wing vehicle design. Without an efficient trim algorithm, trial-and-error based identification of the trimmed wing kinematics is computationally expensive for any flight condition, because the large number of simulations required make the process impractical. In a global sense the nature of forces produced by flapping wings closely resemble those on a helicopter blade, such that an analogy can be drawn between the two. Therefore, techniques developed for helicopter performance calculations are adapted and applied to the flapping wing platform particularly for analyzing steady flight. Using a flight dynamic model of the insect, which comes embedded with simplified quasi- steady wing aerodynamics and is coupled to high-fidelity CFD analysis, trim solutions are obtained in realistic time frames. This procedure is analogous to rotorcraft periodic coupling for trim. This multi-fidelity approach, where many quasi-steady calculations are combined with a judicious number of CFD simulations, may be used in parametric sweeps and design studies to improve hover and cruise performance. It was shown that the coupled trim methodology based on the QS model is capable of driving the CFD towards a stable trim solution. In forward flight the trim procedure tilts the stroke plane resulting in lift generation during downstroke and propulsive force during upstroke. The airloads, thrust and power are affected by the trim parameters, and the CFD/QS methodology accurately accounted for these inter-dependencies. Also it is observed that power initially decreases as an insect goes from hover to forward flight

  5. Water

    Science.gov (United States)

    ... environment and your health: Green living Sun Water Health effects of water pollution How to protect yourself from water pollution Air Chemicals Noise Quizzes Links to more information girlshealth glossary girlshealth. ...

  6. Water Research Consortium U.S. Department of Energy Grant Award Number DE-FG02-05ER64132 Final Technical Report For Period Beginning: 15 September 2005 And Ending: 31 December 2009 Report Date: 16 March 2010

    Energy Technology Data Exchange (ETDEWEB)

    Steven R. Billingsley

    2010-03-18

    This report summarizes the activities of the INRA Water Research Consortium (IWRC) for the period beginning September 15, 2005 and ending December 16, 2010. This report compares accomplishments to project objectives, documents the activities associated with this project, and lists products developed during the course of the project. The Water Resources Research Needs Assessment team received funding from the Inland Northwest Research Alliance Water Resources Steering Committee to facilitate a structured needs assessment process that could provide a basis for future targeted research efforts to improve regional water resources management in the Inland Northwest region. The original INRA proposal specifically mentions the need to conduct a detailed assessment of the information and research needs of policy makers and water user groups during a period of increasing competition for scarce water supplies. A particular focus of this assessment would be to understand what types of research might facilitate water resource management during periods of drought. The specific goals of the Needs Assessment project were to: (1) Quickly ascertain the perceptions of diverse stakeholders in this region; (2) Condense this complex information into a format that can be shared with the INRA scientific panel, and (3) Develop of a realistic set of research needs & priorities that can shape future INRA-funded research activities.

  7. Modeling chemical accumulation in sediment of small waterbodies accounting for sediment transport and water-sediment exchange processes over long periods.

    Science.gov (United States)

    Patterson, David Albert; Strehmel, Alexander; Erzgräber, Beate; Hammel, Klaus

    2017-12-01

    In a recent scientific opinion of the European Food Safety Authority it is argued that the accumulation of plant protection products in sediments over long time periods may be an environmentally significant process. Therefore, the European Food Safety Authority proposed a calculation to account for plant protection product accumulation. This calculation, however, considers plant protection product degradation within sediment as the only dissipation route, and does not account for sediment dynamics or back-diffusion into the water column. The hydraulic model Hydrologic Engineering Center-River Analysis System (HEC-RAS; US Army Corps of Engineers) was parameterized to assess sediment transport and deposition dynamics within the FOrum for Co-ordination of pesticide fate models and their USe (FOCUS) scenarios in simulations spanning 20 yr. The results show that only 10 to 50% of incoming sediment would be deposited. The remaining portion of sediment particles is transported across the downstream boundary. For a generic plant protection product substance this resulted in deposition of only 20 to 50% of incoming plant protection product substance. In a separate analysis, the FOCUS TOXSWA model was utilized to examine the relative importance of degradation versus back-diffusion as loss processes from the sediment compartment for a diverse range of generic plant protection products. In simulations spanning 20 yr, it was shown that back-diffusion was generally the dominant dissipation process. The results of the present study show that sediment dynamics and back-diffusion should be considered when calculating long-term plant protection product accumulation in sediment. Neglecting these may lead to a systematic overestimation of accumulation. Environ Toxicol Chem 2017;36:3223-3231. © 2017 SETAC. © 2017 SETAC.

  8. Steady Particle States of Revised Electromagnetics

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2006-07-01

    Full Text Available A revised Lorentz invariant electromagnetic theory leading beyond Maxwell’s equations, and to a form of extended quantum electrodynamics, has been elaborated on the basis of a nonzero electric charge density and a nonzero electric field divergence in the vacuum state. Among the applications of this theory, there are steady electromagnetic states having no counterpart in conventional theory and resulting in models of electrically charged and neutral leptons, such as the electron and the neutrino. The analysis of the electron model debouches into a point-charge-like geometry with a very small characteristic radius but having finite self-energy. This provides an alternative to the conventional renormalization procedure. In contrast to conventional theory, an integrated radial force balance can further be established in which the electron is prevented from “exploding” under the action of its net self-charge. Through a combination of variational analysis and an investigation of the radial force balance, a value of the electronic charge has been deduced which deviates by only one percent from that obtained in experiments. This deviation requires further investigation. A model of the neutrino finally reproduces some of the basic features, such as a small but nonzero rest mass, an angular momentum but no magnetic moment, and long mean free paths in solid matter.

  9. Steady Particle States of Revised Electromagnetics

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2006-07-01

    Full Text Available A revised Lorentz invariant electromagnetic theory leading beyond Maxwell's equations, and to a form of extended quantum electrodynamics, has been elaborated on the basis of a nonzero electric charge density and a nonzero electric field divergence in the vacuum state. Among the applications of this theory, there are steady electromagnetic states having no counterpart in conventional theory and resulting in models of electrically charged and neutral leptons, such as the electron and the neutrino. The analysis of the electron model debouches into a point-charge-like geometry with a very small characteristic radius but having finite self-energy. This provides an alternative to the conventional renormalization procedure. In contrast to conventional theory, an integrated radial force balance can further be established in which the electron is prevented from "exploding" under the action of its net self-charge. Through a combination of variational analysis and an investigation of the radial force balance, a value of the electronic charge has been deduced which deviates by only one percent from that obtained in experiments. This deviation requires further investigation. A model of the neutrino finally reproduces some of the basic features, such as a small but nonzero rest mass, an angular momentum but no magnetic moment, and long mean free paths in solid matter.

  10. Maximal lactate steady state in Judo.

    Science.gov (United States)

    de Azevedo, Paulo Henrique Silva Marques; Pithon-Curi, Tania; Zagatto, Alessandro Moura; Oliveira, João; Perez, Sérgio

    2014-04-01

    the purpose of this study was to verify the validity of respiratory compensation threshold (RCT) measured during a new single judo specific incremental test (JSIT) for aerobic demand evaluation. to test the validity of the new test, the JSIT was compared with Maximal Lactate Steady State (MLSS), which is the gold standard procedure for aerobic demand measuring. Eight well-trained male competitive judo players (24.3 ± 7.9 years; height of 169.3 ± 6.7cm; fat mass of 12.7 ± 3.9%) performed a maximal incremental specific test for judo to assess the RCT and performed on 30-minute MLSS test, where both tests were performed mimicking the UchiKomi drills. the intensity at RCT measured on JSIT was not significantly different compared to MLSS (p=0.40). In addition, it was observed high and significant correlation between MLSS and RCT (r=0.90, p=0.002), as well as a high agreement. RCT measured during JSIT is a valid procedure to measure the aerobic demand, respecting the ecological validity of Judo.

  11. Steady-state creep in the mantle

    Directory of Open Access Journals (Sweden)

    G. RANALLI

    1977-06-01

    Full Text Available SUMMARY - The creep equations for steady-state flow of olivine at high
    pressure and temperature are compared in an attempt to elucidate the rheological
    behaviour of the mantle. Results are presented in terms of applied deformation
    maps and curves of effective viscosity v depth.
    In the upper mantle, the transition stress between dislocation and diffusion
    creep is between 10 to 102 bar (as orders of magnitude for grain sizes from
    0.01 to 1 cm. The asthenosphere under continents is deeper, and has higher
    viscosity, than under oceans. Predominance of one creep mechanism above the
    others depends on grain size, strain rate, and volume fraction of melt; the
    rheological response can be different for different geodynamic processes.
    In the lower mantle, on the other hand, dislocation creep is predominant
    at all realistic grain sizes and strain rates. If the effective viscosity has to be only
    slightly higher than in the upper mantle, as some interpretations of glacioisostatic
    rebound suggest, then the activation volume cannot be larger than
    11 cm3 mole^1.

  12. Motor responses to a steady beat.

    Science.gov (United States)

    Schaefer, Rebecca S; Overy, Katie

    2015-03-01

    It is increasingly well established that music containing an isochronous pulse elicits motor responses at the levels of both brain and behavior. Such motor responses are often used in pedagogical and clinical practice to induce movement, particularly where motor functions are impaired. However, the complex nature of such apparently universal human responses has, arguably, not received adequate research attention to date. In particular, it should be noted that many adults, including those with disabilities, find it somewhat difficult to synchronize their movements with a beat with perfect accuracy; indeed, perfecting the skill of being musically "in time" can take years of training during childhood. Further research is needed on the nature of both the specificity and range of motor responses that can arise from the perception of a steady auditory pulse, with different populations, musical stimuli, conditions, and required levels of accuracy in order to better understand and capture the potential value of the musical beat as a pedagogical and therapeutic tool. © 2015 New York Academy of Sciences.

  13. Loudness of steady sounds - A new theory

    Science.gov (United States)

    Howes, W. L.

    1979-01-01

    A new mathematical theory for calculating the loudness of steady sounds from power summation and frequency interaction, based on psychoacoustic and physiological information, assuems that loudness is a subjective measure of the electrical energy transmitted along the auditory nerve to the central nervous system. The auditory system consists of the mechanical part modeled by a bandpass filter with a transfer function dependent on the sound pressure, and the electrical part where the signal is transformed into a half-wave reproduction represented by the electrical power in impulsive discharges transmitted along neurons comprising the auditory nerve. In the electrical part the neurons are distributed among artificial parallel channels with frequency bandwidths equal to 'critical bandwidths for loudness', within which loudness is constant for constant sound pressure. The total energy transmitted to the central nervous system is the sum of the energy transmitted in all channels, and the loudness is proportional to the square root of the total filtered sound energy distributed over all channels. The theory explains many psychoacoustic phenomena such as audible beats resulting from closely spaced tones, interaction of sound stimuli which affect the same neurons affecting loudness, and of individually subliminal sounds becoming audible if they lie within the same critical band.

  14. Fluctuations When Driving Between Nonequilibrium Steady States

    Science.gov (United States)

    Riechers, Paul M.; Crutchfield, James P.

    2017-08-01

    Maintained by environmental fluxes, biological systems are thermodynamic processes that operate far from equilibrium without detailed-balanced dynamics. Yet, they often exhibit well defined nonequilibrium steady states (NESSs). More importantly, critical thermodynamic functionality arises directly from transitions among their NESSs, driven by environmental switching. Here, we identify the constraints on excess heat and dissipated work necessary to control a system that is kept far from equilibrium by background, uncontrolled "housekeeping" forces. We do this by extending the Crooks fluctuation theorem to transitions among NESSs, without invoking an unphysical dual dynamics. This and corresponding integral fluctuation theorems determine how much work must be expended when controlling systems maintained far from equilibrium. This generalizes thermodynamic feedback control theory, showing that Maxwellian Demons can leverage mesoscopic-state information to take advantage of the excess energetics in NESS transitions. We also generalize an approach recently used to determine the work dissipated when driving between functionally relevant configurations of an active energy-consuming complex system. Altogether, these results highlight universal thermodynamic laws that apply to the accessible degrees of freedom within the effective dynamic at any emergent level of hierarchical organization. By way of illustration, we analyze a voltage-gated sodium ion channel whose molecular conformational dynamics play a critical functional role in propagating action potentials in mammalian neuronal membranes.

  15. Steady progress toward a malaria vaccine.

    Science.gov (United States)

    Lyke, Kirsten E

    2017-10-01

    Great progress has been made in reducing malaria morbidity and mortality, yet the parasite continues to cause a startling 200 million infections and 500 000 deaths annually. Malaria vaccine development is pushing new boundaries by steady advancement toward a licensed product. Despite 50 years of research, the complexity of Plasmoidum falciparum confounds all attempts to eradicate the organism. This very complexity has pushed the boundaries of vaccine development to new heights, yet it remains to be seen if an affordable vaccine can provide durable and high-level protection. Novel vaccines such as RTS,S/AS01E are on the edge of licensure, but old techniques have resurged with the ability to deliver vialed, whole organism vaccines. Novel adjuvants, multistage/multiantigen approaches and transmission blocking vaccines all contribute to a multipronged battle plan to conquer malaria. Vaccines are the most cost-effective tools to control infectious diseases, yet the complexity of malaria has frustrated all attempts to develop an effective product. This review concentrates on recent advances in malaria vaccine development that lend hope that a vaccine can be produced and malaria eradicated.

  16. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  17. Records of wells and chemical analyses of water from wells for the period June 13, 1984 to December 4, 1986 at the Maxey Flats Radioactive Waste Disposal Site, Kentucky

    Science.gov (United States)

    Lyverse, M.A.

    1987-01-01

    Lithologic data are presented for 113 wells drilled at the Maxey Flats Radioactive Waste Disposal Site for the period June 13, 1984 to December 4, 1986. Water levels, tritium concentrations, and specific conductance are also presented for wells yielding sufficient water for measuring and sampling. At least one sample was collected from most wells for the determination of gross alpha and beta activity. These activities and the results for gamma emitting radionuclides (Cobalt 60 and Cesium 137) are also presented. (USGS)

  18. Modeling non-steady state radioisotope transport in the vadose zone - A case study using uranium isotopes at Peña Blanca, Mexico

    Science.gov (United States)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-10-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and 234U/ 238U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and α-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Peña Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced 234U/ 238U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using 234U/ 238U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  19. Modeling non-steady state radioisotope transport in the vadose zone--A case study using uranium isotopes at Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-06-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and {sup 234}U/{sup 238}U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and {alpha}-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Pena Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced {sup 234}U/{sup 238}U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using {sup 234}U/{sup 238}U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  20. Improved convection cooling in steady channel flows

    Science.gov (United States)

    Alben, Silas

    2017-10-01

    A fundamental problem in heat transfer is the convective cooling of the heated walls of a channel. We find steady two-dimensional (2D) flows that maximize the heat removed from fixed-temperature walls for a given rate of energy used to drive the flow, Pe2 (Pe is the Peclet number, a dimensionless flow speed). For parabolic (Poiseuille) flow, the heat transfer scales as Pe1/3. Starting from Poiseuille flow, we compute a sequence of optima using Newton's method with continuation. Computed optimal flows are found to be approximately unidirectional and nearly uniform outside of sharp boundary layers at the channel walls. A linear approximation near Poiseuille flow shows how the thermal boundary layer generates a boundary layer in the optimal flow. We are thus led to compute optimal unidirectional flows with boundary layers, for which the heat transfer scales as Pe2/5, an improvement over the Pe1/3 Poiseuille flow scaling. The optimal flows have viscous dissipation concentrated in boundary layers of thickness ˜Pe-2/5 at the channel walls, and have a uniform velocity ˜Pe4/5 outside the boundary layers. We explain the scalings using physical and mathematical arguments. We also show that with channels of aspect ratio (length/height) L , the outer flow speed scales as L-1 /5 and the boundary layer thickness scales as L3 /5 in the unidirectional approximation. At the Reynolds numbers near the turbulent transition for 2D Poiseuille flow in air, we find a 60% increase in heat transferred over that of Poiseuille flow.

  1. Contra-expertise on determination of radioactivity of waste water and ventilation air of Urenco Nederland B.V. Period 2011; Contra-expertise op bepalingen van radioactiviteit van afvalwater en ventilatielucht van Urenco Nederland BV. Periode 2011

    Energy Technology Data Exchange (ETDEWEB)

    Kwakman, P.J.M.; Overwater, R.M.W.

    2012-08-15

    Within the framework of a monitoring programme, RIVM measures the release of radioactivity into the waste water and atmosphere of the Urenco uranium enrichment plant in Almelo, Netherlands. Measurements are carried out eight times per year. This form of counter-expertise is aimed at verifying and supporting the reliability of the analyses carried out by the Urenco plant. As a rule, the waste water contains very low levels of gross alpha and gross beta activity. The two different sets of measurements of gross alpha and gross beta in waste water are generally in agreement, as is also the case in 2011. Radioactivity levels in the ventilation air are very close to those levels expected due to the natural presence of radon in the outside atmosphere. For gross alpha 0,007 - 0,13 mBq.m{sup -3} was found and for gross beta 0,026 - 0,5 mBq.m{sup -3}. The agreement with the measurement results of Urenco was mostly good. Taking into account the natural gross-beta activity, and the ratio gross alpha / gross beta it is possible that at SP4 in two cases a small release of uranium may have occurred. The RIVM determined the gross alpha and gross beta activity in eight waste water samples and 40 samples of ventilation air. The samples were taken by Urenco at time points dispersed throughout 2011. This procedure provides the RIVM with a method for determining the release of artificial alpha emitters into the environment. The analyses were carried out on behalf of the Department of Nuclear Safety, Security and Safeguards of the Human Environment and Transport Inspectorate from the Ministry of Infrastructure and Environment [Dutch] Het RIVM controleert achtmaal per jaar de metingen van de verrijkingsfabriek Urenco te Almelo. Het gaat hierbij om lozingen van radioactiviteit in water en lucht. De contra-expertise onderbouwt de betrouwbaarheid van de analyses die Urenco uitvoert. Uit de metingen blijkt dat er in het afvalwater doorgaans een (zeer) lage totaal {alpha} en totaal {beta

  2. Water Quality Conditions Monitored at the Corps’ Fort Peck Project in Montana during the 3-Year Period 2004 through 2006

    Science.gov (United States)

    2007-03-01

    standards. As such, the reservoir is to be maintained suitable for drinking, culinary , and food processing purposes, after conventional treatment; bathing...to the Montana/North Dakota state line. Both B-2 and B-3 waters are to be maintained suitable for drinking, culinary and food processing purposes...QUAL-W2 is a “state-of-the- art ” water quality model that can greatly facilitate addressing reservoir water quality management issues. CE-QUAL-W2 is a

  3. Estimation of Shallow Groundwater Recharge Using a Gis-Based Distributed Water Balance Model

    OpenAIRE

    Graf Renata; Przybyłek Jan

    2014-01-01

    In the paper we present the results of shallow groundwater recharge estimation using the WetSpass GISbased distributed water balance model. By taking into account WetSpass, which stands for Water an Energy Transfer between Soil, Plants and Atmosphere under quasi-Steady State, for average conditions during the period 1961–2000, we assessed the spatial conditions of the groundwater infiltration recharge process of shallow circulation systems in the Poznan Plateau area (the Great Pol...

  4. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2014

    Science.gov (United States)

    Beman, Joseph E.

    2015-10-21

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is hydrologically defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when treatment and distribution of surface water from the Rio Grande through the San Juan-Chama Drinking Water Project began. A 20-percent population increase in the basin from 1990 to 2000 and a 22-percent population increase from 2000 to 2010 resulted in an increased demand for water.

  5. Water

    Science.gov (United States)

    Leopold, Luna Bergere; Baldwin, Helene L.

    1962-01-01

    What do you use water for?If someone asked you this question you would probably think right away of water for drinking. Then you would think of water for bathing, brushing teeth, flushing the toilet. Your list would get longer as you thought of water for cooking, washing the dishes, running the garbage grinder. Water for lawn watering, for play pools, for swimming pools, for washing the car and the dog. Water for washing machines and for air conditioning. You can hardly do without water for fun and pleasure—water for swimming, boating, fishing, water-skiing, and skin diving. In school or the public library, you need water to wash your hands, or to have a drink. If your home or school bursts into flames, quantities of water are needed to put it out.In fact, life to Americans is unthinkable without large supplies of fresh, clean water. If you give the matter a little thought, you will realize that people in many countries, even in our own, may suffer from disease and dirt simply because their homes are not equipped with running water. Imagine your own town if for some reason - an explosion, perhaps - water service were cut off for a week or several weeks. You would have to drive or walk to a neighboring town and bring water back in pails. Certainly if people had to carry water themselves they might not be inclined to bathe very often; washing clothes would be a real chore.Nothing can live without water. The earth is covered by water over three-fourths of its surface - water as a liquid in rivers, lakes and oceans, and water as ice and snow on the tops of high mountains and in the polar regions. Only one-quarter of our bodies is bone and muscle; the other three-fourths is made of water. We need water to live, and so do plants and animals. People and animals can live a long time without food, but without water they die in a few days. Without water, everything would die, and the world would turn into a huge desert.

  6. Chlorine decay under steady and unsteady-state hydraulic conditions

    DEFF Research Database (Denmark)

    Stoianov, Ivan; Aisopou, Angeliki

    2014-01-01

    This paper describes a simulation framework for the scale-adaptive hydraulic and chlorine decay modelling under steady and unsteady-state flows. Bulk flow and pipe wall reaction coefficients are replaced with steady and unsteady-state reaction coefficients. An unsteady decay coefficient is defined...

  7. Interpretation of the exergy equation for steady-flow processes

    NARCIS (Netherlands)

    Siemons, R.V.

    1986-01-01

    We define and discuss the terms in exergy equations, with particular reference to the role of chemical terms in the exergy loss for steady-flow processes. Although there is a chemical contribution to exergy, exergy losses of steady-flow processes may be calculated by using a simple expression for

  8. Mechanism of Non-Steady State Dissolution of Goethite in the Presence of Siderophores

    Science.gov (United States)

    Reichard, P. U.; Kretzschmar, R.; Kraemer, S. M.

    2003-12-01

    Iron is an essential micronutrient for almost all known organisms. Bacteria, fungi, and graminaceous plants are capable of exuding siderophores as part of an iron acquisition strategy. The production of these strong iron chelating ligands is induced by iron limited conditions. Grasses under iron stress, for example, exude phytosiderophores into the rhizosphere in a special diurnal rhythm (Roemheld and Marschner 1986). A few hours after sunrise the exudation starts, culminates around noon and is shut down again until about 4 hours after noon. The phytosiderophores diffuse into the rhizosphere (Marschner et al. 1986) and are passively back transported to the plants by advective flow induced by high transpiration around noon. Despite a fairly short residence time of the phytosiderophores in the rhizosphere, it is a very effective strategy for iron acquisition. To investigate the effect of such pulse inputs of siderophores on iron acquisition, we studied the dissolution mechanism of goethite (alpha-FeOOH), a mineral phase common in soils, under non-steady state conditions. In consideration of the chemical complexity of the rhizosphere, we also investigated the effect of other organic ligands commonly found in the rhizosphere (e. g. oxalate) on the dissolution kinetics. The dissolution experiments were conducted in batch reactors with a constant goethite solids concentration of 2.5 g/l, an ionic strength of 0.01 M, a pH of 6 and 100 microM oxalate. To induce non-steady state conditions, 3 mM phytosiderophores were added to a batch after the goethite-oxalate suspension reacted for a certain time period. Before the siderophore was added to the goethite-oxalate suspension, no dissolution of iron was observed. But, with the addition of the siderophore, a high rate was observed for the iron mobilization under these non-steady state conditions that subsequently was followed by a slow steady state dissolution rate. The results of these non-steady state experiments are very

  9. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2010

    Science.gov (United States)

    Beman, Joseph E.

    2011-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25-40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the basin human population from 1990 to 2000 and about a 22 percent increase from 2000 to 2010 also resulted in an increased demand for water. A network of wells was established by the U.S. Geological Survey in cooperation with the City of Albuquerque to monitor changes in groundwater levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2010), the network consists of 124 wells and piezometers (a piezometer is a small-diameter subwell usually nested within a larger well). To better help the Albuquerque Bernalillo County Water Utility Authority manage water use, this report presents water-level data collected by U.S. Geological Survey personnel at those 124 sites through water year 2010.

  10. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2012

    Science.gov (United States)

    Beman, Joseph E.

    2013-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25-40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. A population increase of about 20 percent in the basin from 1990 to 2000 and a 22 percent increase from 2000 to 2010 resulted in an increased demand for water. An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2012), the network consists of 126 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (ABCWUA), currently (2012) measures and reports water levels from the 126 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 126 sites through water year 2012.

  11. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2011

    Science.gov (United States)

    Beman, Joseph E.

    2012-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the basin human population from 1990 to 2000 and of about 22 percent increase from 2000 to 2010 also resulted in an increased demand for water. A network of wells was established by the U.S. Geological Survey in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2011), the network consists of 126 wells and piezometers (a piezometer is a specialized well open to a specific depth in the aquifer and is often of small diameter and nested with other piezometers open to different depths). This report presents water-level data collected by U.S. Geological Survey personnel at those 126 sites through water year 2011 to better help the Albuquerque Bernalillo County Water Utility Authority manage water use.

  12. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2013

    Science.gov (United States)

    Beman, Joseph E.

    2014-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when treatment and distribution of surface water from the Rio Grande began. A population increase of about 20 percent in the basin from 1990 to 2000 and a 22-percent increase from 2000 to 2010 resulted in an increased demand for water. An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2013), the network consists of 123 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the Albuquerque Bernalillo County Water Utility Authority, currently (2013) measures and reports water levels from the 123 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 123 sites through water year 2013.

  13. [The influence of ecological factors on the formation of the parasite fauna of the common roach Rutilus rutilus Linnaeus (1758) in different periods of water abundance in Lake Sartlan (Southwestern Siberia)].

    Science.gov (United States)

    Sous', S M

    2011-01-01

    An analysis of the formation of the parasitofauna of the common roach under the influence of various biotic and abiotic environmental factors during three high water cycles observed in the last century is given. Periods of the formation of the enzooty are established.

  14. Steady state fractionation of heavy noble gas isotopes in a deep unsaturated zone

    Science.gov (United States)

    Seltzer, Alan M.; Severinghaus, Jeffrey P.; Andraski, Brian J.; Stonestrom, David A.

    2017-01-01

    To explore steady state fractionation processes in the unsaturated zone (UZ), we measured argon, krypton, and xenon isotope ratios throughout a ∼110 m deep UZ at the United States Geological Survey (USGS) Amargosa Desert Research Site (ADRS) in Nevada, USA. Prior work has suggested that gravitational settling should create a nearly linear increase in heavy-to-light isotope ratios toward the bottom of stagnant air columns in porous media. Our high-precision measurements revealed a binary mixture between (1) expected steady state isotopic compositions and (2) unfractionated atmospheric air. We hypothesize that the presence of an unsealed pipe connecting the surface to the water table allowed for direct inflow of surface air in response to extensive UZ gas sampling prior to our first (2015) measurements. Observed isotopic resettling in deep UZ samples collected a year later, after sealing the pipe, supports this interpretation. Data and modeling each suggest that the strong influence of gravitational settling and weaker influences of thermal diffusion and fluxes of CO2 and water vapor accurately describe steady state isotopic fractionation of argon, krypton, and xenon within the UZ. The data confirm that heavy noble gas isotopes are sensitive indicators of UZ depth. Based on this finding, we outline a potential inverse approach to quantify past water table depths from noble gas isotope measurements in paleogroundwater, after accounting for fractionation during dissolution of UZ air and bubbles.

  15. Steady state fractionation of heavy noble gas isotopes in a deep unsaturated zone

    Science.gov (United States)

    Seltzer, Alan M.; Severinghaus, Jeffrey P.; Andraski, Brian J.; Stonestrom, David A.

    2017-04-01

    To explore steady state fractionation processes in the unsaturated zone (UZ), we measured argon, krypton, and xenon isotope ratios throughout a ˜110 m deep UZ at the United States Geological Survey (USGS) Amargosa Desert Research Site (ADRS) in Nevada, USA. Prior work has suggested that gravitational settling should create a nearly linear increase in heavy-to-light isotope ratios toward the bottom of stagnant air columns in porous media. Our high-precision measurements revealed a binary mixture between (1) expected steady state isotopic compositions and (2) unfractionated atmospheric air. We hypothesize that the presence of an unsealed pipe connecting the surface to the water table allowed for direct inflow of surface air in response to extensive UZ gas sampling prior to our first (2015) measurements. Observed isotopic resettling in deep UZ samples collected a year later, after sealing the pipe, supports this interpretation. Data and modeling each suggest that the strong influence of gravitational settling and weaker influences of thermal diffusion and fluxes of CO2 and water vapor accurately describe steady state isotopic fractionation of argon, krypton, and xenon within the UZ. The data confirm that heavy noble gas isotopes are sensitive indicators of UZ depth. Based on this finding, we outline a potential inverse approach to quantify past water table depths from noble gas isotope measurements in paleogroundwater, after accounting for fractionation during dissolution of UZ air and bubbles.

  16. Water

    Science.gov (United States)

    ... the tap as described). 3. In all situations, drink or cook only with water that comes out of the tap cold. Water that comes out of the tap warm or hot can contain much higher levels of lead. Boiling ...

  17. Robotic finger perturbation training improves finger postural steadiness and hand dexterity.

    Science.gov (United States)

    Yoshitake, Yasuhide; Ikeda, Atsutoshi; Shinohara, Minoru

    2018-02-01

    The purpose of the study was to understand the effect of robotic finger perturbation training on steadiness in finger posture and hand dexterity in healthy young adults. A mobile robotic finger training system was designed to have the functions of high-speed mechanical response, two degrees of freedom, and adjustable loading amplitude and direction. Healthy young adults were assigned to one of the three groups: random perturbation training (RPT), constant force training (CFT), and control. Subjects in RPT and CFT performed steady posture training with their index finger using the robot in different modes: random force in RPT and constant force in CFT. After the 2-week intervention period, fluctuations of the index finger posture decreased only in RPT during steady position-matching tasks with an inertial load. Purdue pegboard test score improved also in RPT only. The relative change in finger postural fluctuations was negatively correlated with the relative change in the number of completed pegs in the pegboard test in RPT. The results indicate that finger posture training with random mechanical perturbations of varying amplitudes and directions of force is effective in improving finger postural steadiness and hand dexterity in healthy young adults. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Suppression of Dynamic Stall by Steady and Pulsed Upper-Surface Blowing

    Science.gov (United States)

    Weaver, D.; McAlister, K. W.; Tso, J.

    1996-01-01

    The Boeing-Vertol VR-7 airfoil was experimentally studied with steady and pulsed upper-surface blowing for sinusoidal pitching oscillations described by alpha = alpha(sub m) + 10 deg sin(omega t). The tests were conducted in the U.S. Army Aeroflightdynamics Directorate's Water Tunnel at NASA Ames Research Center. The experiment was performed at a Reynolds number of 100,000. Pitch oscillations with alpha(sub m) = 10 deg and 15 deg and with reduced frequencies ranging from k = 0.005 to 0.15 were examined. Blowing conditions ranged from C(sub mu) = 0.03 to 0.66 and F(+) = 0 to 3. Unsteady lift, drag, and pitching-moment loads were measured, and fluorescent-dye flow visualizations were obtained. Steady, upper-surface blowing was found to be capable of trapping a separation bubble near the leading edge during a portion of the airfoil's upward rotation. When this occurred, the lift was increased significantly and stall was averted. In all cases, steady blowing reduced the hysteresis amplitudes present in the loads and produced a large thrust force. The benefits of steady blowing diminished as the reduced frequency and mean angle of oscillation increased. Pulsed blowing showed only marginal benefits for the conditions tested. The greatest gains from pulsed blowing were achieved at F(+) = 0.9.

  19. A steady-state and pre-steady-state kinetics study of the tungstoenzyme formaldehyde ferredoxin oxidoreductase from Pyrococcus furiosus

    NARCIS (Netherlands)

    Bol, E.; Broers, N.J.; Hagen, W.R.

    2007-01-01

    Formaldehyde ferredoxin oxidoreductase from Pyrococcus furiosus is a homotetrameric protein with one tungstodipterin and one [4Fe–4S] cubane per 69-kDa subunit. The enzyme kinetics have been studied under steady-state conditions at 80 °C and pre-steady state conditions at 50 °C, in the latter case

  20. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2015

    Science.gov (United States)

    Beman, Joseph E.; Bryant, Christina F.

    2016-10-27

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is hydrologically defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift between San Acacia to the south and Cochiti Lake to the north. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) began treatment and distribution of surface water from the Rio Grande through the San Juan-Chama Drinking Water Project. A 20-percent population increase in the basin from 1990 to 2000 and a 22-percent population increase from 2000 to 2010 may have resulted in an increased demand for water in areas within the basin.An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the Albuquerque Basin. In 1983, this network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. The network currently (2015) consists of 124 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the ABCWUA, currently (2015) measures and reports water levels from the 124 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 124 sites through water year 2015 (October 1, 2014, through September 30, 2015).

  1. Critical Concavity of a Drainage Basin for Steady-State

    Science.gov (United States)

    Byun, Jongmin; Paik, Kyungrock

    2015-04-01

    Longitudinal profiles of natural streams are known to show concave forms. Saying A as drainage area, channel gradient S can be expressed as the power-law, S≈A-θ (Flint, 1974), which is one of the scale-invariant features of drainage basin. According to literature, θ of most natural streams falls into a narrow range (0.4 natural drainage basins?' To answer above questions, we analytically derive θ for a steady-state drainage basin following Lane's equilibrium (Lane, 1955) throughout the corridor and named this specific case as the 'critical concavity'. In the derivation, sediment transport capacity is estimated by unit stream power model (Yang, 1976), yielding a power function of upstream area. Stability of channel at a local point occurs when incoming flux equals outgoing flux at the point. Therefore, given the drainage at steady-state where all channel beds are stable, the exponent of the power function should be zero. From this, we can determine the critical concavity. Considering ranges of variables associated in this derivation, critical concavity cannot be resolved as a single definite value, rather a range of critical concavity is suggested. This range well agrees with the widely reported range of θ (0.4 natural streams. In this theoretical study, inter-relationships between power-laws such as hydraulic geometry (Leopold and Maddock, 1953), dominant discharge-drainage area (Knighton et al., 1999), and concavity, are coupled into the power-law framework of stream power sediment transport model. This allows us to explore close relationships between their power-law exponents: their relative roles and sensitivity. Detailed analysis and implications will be presented. References Flint, J. J., 1974, Stream gradient as a function of order, magnitude, and discharge, Water Resources Research, 10, 969-973. Knighton, A. D., 1999, Downstream variation in stream power, Geomorphology, 29, 293-306. Lane, E. W., 1955, The importance of fluvial morphology in hydraulic

  2. Theoretical and experimental study of development of two-dimensional steady and unsteady wakes within curved channels

    Energy Technology Data Exchange (ETDEWEB)

    Schobeiri, M.T.; Pappu, K.; John, J. [Texas A and M Univ., College Station, TX (United States) Turbomachinery Performance Lab.

    1995-12-01

    Development of steady and periodic unsteady wake flows downstream of stationary and rotating cylindrical rods within a curved channel under zero longitudinal pressure gradient is theoretically and experimentally investigated. Wake quantities such as the mean velocity and turbulent fluctuations in longitudinal and lateral directions, as well as the turbulent shear stress, are measured. For the nondimensionalized velocity defect, affine profiles are observed throughout the flow regime. Based on these observations and using the transformed equations of motion and continuity, a theoretical frame work is established that generally describes the two-dimensional curvilinear wake flow. To confirm the theory, development of steady and periodic unsteady wakes in the above curved channel are experimentally investigated. The detailed comparison between the measurement and the theory indicates that the complex steady and unsteady wake flows are very well predicted.

  3. Perbandingan Hasil Pemodelan Aliran Satu Dimensi Unsteady Flow dan Steady Flow pada Banjir Kota

    Directory of Open Access Journals (Sweden)

    Andreas Tigor Oktaga

    2016-06-01

    Full Text Available One dimensional flow is often used as a flood simulation for the planning capacity of the river. Flood is a type of unsteady non-uniform flow, that can be simulated using HEC-RAS. HEC-RAS software is often used for flood modeling with a one-dimensional flow method. Unsteady flow modeling results in HEC-RAS sometimes refer to error and warning due to unstable analysis program. The stability program among others influenced bend in the river flow, the steep slope of the river bottom, and changes in cross-section shape. Because the flood handling required maximum discharge and maximum flood water level, then a steady flow is often used as an alternative to simulate the flood flow. This study aimed to determine the advantages and disadvantages of modeling unsteady non-uniform and steady non-uniform flow. The research location in the Kanal Banjir Barat, in the Semarang City. Hydraulics modeling uses HEC-RAS 4.1 and for discharge the plan is obtained from the HEC-HMS 3.5. Results of the comparison modeling hydraulics the modeling of steady non-uniform flow has a tendency water level is higher and modeling of unsteady non-uniform flow takes longer to analyze. Results of the comparison the average flood water level maximun is less than 15%  (± 0,3 meters, that is 0.27 meters (13.16% for Q50, 0.25 meters (11.56% for Q100, dan 0.16 meters (4.73% for Q200. So the modeling steady non-uniform flow can still be used as a companion version the modeling unsteady non-uniform flow.

  4. Steady electric fields and currents elementary electromagnetic theory

    CERN Document Server

    Chirgwin, B H; Kilmister, C W

    2013-01-01

    Steady Electric Fields and Currents, Volume 1 is an introductory text to electromagnetism and potential theory. This book starts with the fields associated with stationary charges and unravels the stationary condition to allow consideration of the flow of steady currents in closed circuits. The opening chapter discusses the experimental results that require mathematical explanation and discussion, particularly those referring to phenomena that question the validity of the simple Newtonian concepts of space and time. The subsequent chapters consider steady-state fields, electrostatics, dielectr

  5. Ignition phase and steady-state structures of a non-thermal air plasma

    CERN Document Server

    Lu Xin Pei

    2003-01-01

    An AC-driven, non-thermal, atmospheric pressure air plasma is generated within the gap separating a disc-shaped metal electrode and a water electrode. The ignition phase and the steady-state are studied by a high-speed CCD camera. It is found that the plasma always initiates at the surface of the water electrode. The plasma exhibits different structures depending on the polarity of the water electrode: when the water electrode plays the role of cathode, a relatively wide but visibly dim plasma column is generated. At the maximum driving voltage, the gas temperature is between 800 and 900 K, and the peak current is 67 mA; when the water electrode is anode, the plasma column narrows but increases its light emission. The gas temperature in this case is measured to be in the 1400-1500 K range, and the peak current is 81 mA.

  6. KLIMOPASS: Water-use conflicts during periods of low flow - a stakeholder analysis of the rivers Murg and Kocher in Baden-Wuerttemberg and sustainable recommendations for action

    Science.gov (United States)

    Zeitler, Florian; Dotterweich, Markus; Rothstein, Benno

    2017-04-01

    The 2003 and 2015 occurring heatwaves in Central Europe demonstrated on how dangerous long-lasting droughts and water stress can be for nature, people and companies relying on water. Climate change will increase the chance of low flow events along rivers in Baden-Wuerttemberg in the future leading to possible water-use conflicts amongst the users. This KLIMOPASS project focuses on the identification of existing and potential occurring conflicts of usage and interest for water resources. The main research concentrates on two exemplary river basins in Baden-Wuerttemberg (the Murg and the Kocher River) including all involved stakeholders and sectors (hydropower, agriculture, industry, sewage plants, ecology, tourism etc.). With the examples of the two rivers, the identification of conflicts, possible strategies for solutions and recommendations for action during current and future events of low flow have been researched. Quantitative and qualitative surveys, interviews, excursions and workshops have been conducted to analyse the stakeholder's potential for conflict. For this process it is necessary to equally consider all economic, societal and ecological interests and include all relevant stakeholders in the participatory process. According to the results, water related conflicts are not present in all sectors, but rather exclusive to certain sectors. Furthermore, these sectors are in conflict with more than one stakeholder group at the same time. In contrast, other users have not experienced any water related conflicts yet. Moreover, it is noticeable that conflicts in water use are only partly caused due to low flow events: regarding both rivers, low flow events are not only related to natural causes but particularly to anthropogenic influences.

  7. Short-crested waves in deep water: a numerical investigation of recent laboratory experiments

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Madsen, Per A.

    2006-01-01

    A numerical study of quasi-steady, doubly-periodic monochromatic short-crested wave patterns in deep water is conducted using a high-order Boussinesq-type model. Simulations using linear wavemaker conditions in the nonlinear model are initially used to approximate conditions from recent laboratory...... inclusion of steady third-order components in the wave generation is shown to significantly reduce the modulations (and other unsteady features), further confirming the explanation. This numerical work makes apparent some previously unknown difficulties associated with the physical generation of even...

  8. Slow and Steady May Win This Race.

    Science.gov (United States)

    Blankenship, James C

    2017-08-01

    This retrospective cohort study compares two strategies of stent delivery balloon inflation: inflation for 30 sec and longer as needed to stabilize the balloon pressure for 30 sec at the desired pressure, versus conventional fast inflation/fast deflation of the stent balloon The experimental technique decreased target vessel revascularization by about 50% as assessed by logistic regression and propensity analyses The investigators' recommendation to routinely use their prolonged inflation protocol is supported by six other studies over the past decade demonstrating that long stent balloon inflation produces better outcomes than does short inflation. © 2017 Wiley Periodicals, Inc.

  9. Growth rate controls mRNA turnover in steady and non-steady states.

    Science.gov (United States)

    García-Martínez, José; Troulé, Kevin; Chávez, Sebastián; Pérez-Ortín, José E

    2016-12-01

    Gene expression has been investigated in relation with growth rate in the yeast Saccharomyces cerevisiae, following different experimental strategies. The expression of some specific gene functional categories increases or decreases with growth rate. Our recently published results have unveiled that these changes in mRNA concentration with growth depend on the relative alteration of mRNA synthesis and decay, and that, in addition to this gene-specific transcriptomic signature of growth, global mRNA turnover increases with growth rate. We discuss here these results in relation with other previous and concurrent publications, and we add new evidence which indicates that growth rate controls mRNA turnover even under non-steady-state conditions.

  10. Steady thermal stress and strain rates in a rotating circular cylinder under steady state temperature

    Directory of Open Access Journals (Sweden)

    Pankaj Thakur

    2014-01-01

    Full Text Available Thermal stress and strain rates in a thick walled rotating cylinder under steady state temperature has been derived by using Seth’s transition theory. For elastic-plastic stage, it is seen that with the increase of temperature, the cylinder having smaller radii ratios requires lesser angular velocity to become fully plastic as compared to cylinder having higher radii ratios The circumferential stress becomes larger and larger with the increase in temperature. With increase in thickness ratio stresses must be decrease. For the creep stage, it is seen that circumferential stresses for incompressible materials maximum at the internal surface as compared to compressible material, which increase with the increase in temperature and measure n.

  11. Moon meteoritic seismic hum: Steady state prediction

    Science.gov (United States)

    Lognonne, P.; Feuvre, M.L.; Johnson, C.L.; Weber, R.C.

    2009-01-01

    We use three different statistical models describing the frequency of meteoroid impacts on Earth to estimate the seismic background noise due to impacts on the lunar surface. Because of diffraction, seismic events on the Moon are typically characterized by long codas, lasting 1 h or more. We find that the small but frequent impacts generate seismic signals whose codas overlap in time, resulting in a permanent seismic noise that we term the "lunar hum" by analogy with the Earth's continuous seismic background seismic hum. We find that the Apollo era impact detection rates and amplitudes are well explained by a model that parameterizes (1) the net seismic impulse due to the impactor and resulting ejecta and (2) the effects of diffraction and attenuation. The formulation permits the calculation of a composite waveform at any point on the Moon due to simulated impacts at any epicentral distance. The root-mean-square amplitude of this waveform yields a background noise level that is about 100 times lower than the resolution of the Apollo long-period seismometers. At 2 s periods, this noise level is more than 1000 times lower than the low noise model prediction for Earth's microseismic noise. Sufficiently sensitive seismometers will allow the future detection of several impacts per day at body wave frequencies. Copyright 2009 by the American Geophysical Union.

  12. Seabird transfer of nutrients and trace elements from the north water polynya to land during the mid-holocene warm period, carey islands, northwest Greenland

    DEFF Research Database (Denmark)

    Outridge, Peter M.; Goodsite, Michael Evan; Bennike, Ole

    2016-01-01

    Seabird guano from large nesting colonies is known to increase trace metal levels in adjacent terrestrial environments today, when global oceans are contaminated with Hg, Cd, and other metals. But the effect of seabird guano in the pre-industrial period has rarely been studied. We used stable C......, in which guano markedly increased environmental Hg concentrations. It could be a consequence of Hg concentrations in Arctic marine food webs in the pre-industrial period that were an order of magnitude lower than those of today....

  13. Stabilizing unstable steady states using extended time-delay autosynchronization.

    Science.gov (United States)

    Chang, Austin; Bienfang, Joshua C.; Hall, G. Martin; Gardner, Jeff R.; Gauthier, Daniel J.

    1998-12-01

    We describe a method for stabilizing unstable steady states in nonlinear dynamical systems using a form of extended time-delay autosynchronization. Specifically, stabilization is achieved by applying a feedback signal generated by high-pass-filtering in real time the dynamical state of the system to an accessible system parameter or variables. Our technique is easy to implement, does not require knowledge of the unstable steady state coordinates in phase space, automatically tracks changes in the system parameters, and is more robust to broadband noise than previous schemes. We demonstrate the controller's efficacy by stabilizing unstable steady states in an electronic circuit exhibiting low-dimensional temporal chaos. The simplicity and robustness of the scheme suggests that it is ideally suited for stabilizing unstable steady states in ultra-high-speed systems. (c) 1998 American Institute of Physics.

  14. Shoulder abduction torque steadiness is preserved in subacromial impingement syndrome.

    Science.gov (United States)

    Camargo, Paula Rezende; Avila, Mariana Arias; de Oliveira, Ana Beatriz; Asso, Naoe Aline; Benze, Benedito Galvão; de Fátima Salvini, Tania

    2009-06-01

    This study compared peak torque and torque steadiness during isometric abduction in subjects with subacromial impingement syndrome (SIS) and those with no upper limb disorders. The SIS group consisted of 27 subjects (33.48 +/- 9.94 years) with unilateral SIS. The control group consisted of 23 healthy and active subjects (32.26 +/- 9.04 years). Peak torque and torque steadiness were measured during isometric abduction (80 masculine in the scapular plane) of the shoulder. Standard deviation, coefficient of variation, stability time, median frequency, and relative power were measured from the steadiness trials. There were neither significant interactions between group and side (P > 0.05), nor were there significant main effects of group and side (P > 0.05) for all variables analyzed. The results of this study showed that steadiness is preserved by SIS during isometric abduction of the shoulder.

  15. Hearing Loss Rates Holding Steady for U.S. Teens

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_167456.html Hearing Loss Rates Holding Steady for U.S. Teens: Study Vaccine ... via earphones than ever before, but rates of hearing loss have not increased. Still, "the overall take-home ...

  16. Method and apparatus for adapting steady flow with cyclic thermodynamics

    Science.gov (United States)

    Swift, Gregory W.; Reid, Robert S.; Ward, William C.

    2000-01-01

    Energy transfer apparatus has a resonator for supporting standing acoustic waves at a selected frequency with a steady flow process fluid thermodynamic medium and a solid medium having heat capacity. The fluid medium and the solid medium are disposed within the resonator for thermal contact therebetween and for relative motion therebetween. The relative motion is produced by a first means for producing a steady velocity component and second means for producing an oscillating velocity component at the selected frequency and concomitant wavelength of the standing acoustic wave. The oscillating velocity and associated oscillating pressure component provide energy transfer between the steady flow process fluid and the solid medium as the steady flow process fluid moves through the resonator.

  17. SteadyCom: Predicting microbial abundances while ensuring community stability.

    Directory of Open Access Journals (Sweden)

    Siu Hung Joshua Chan

    2017-05-01

    Full Text Available Genome-scale metabolic modeling has become widespread for analyzing microbial metabolism. Extending this established paradigm to more complex microbial communities is emerging as a promising way to unravel the interactions and biochemical repertoire of these omnipresent systems. While several modeling techniques have been developed for microbial communities, little emphasis has been placed on the need to impose a time-averaged constant growth rate across all members for a community to ensure co-existence and stability. In the absence of this constraint, the faster growing organism will ultimately displace all other microbes in the community. This is particularly important for predicting steady-state microbiota composition as it imposes significant restrictions on the allowable community membership, composition and phenotypes. In this study, we introduce the SteadyCom optimization framework for predicting metabolic flux distributions consistent with the steady-state requirement. SteadyCom can be rapidly converged by iteratively solving linear programming (LP problem and the number of iterations is independent of the number of organisms. A significant advantage of SteadyCom is compatibility with flux variability analysis. SteadyCom is first demonstrated for a community of four E. coli double auxotrophic mutants and is then applied to a gut microbiota model consisting of nine species, with representatives from the phyla Bacteroidetes, Firmicutes, Actinobacteria and Proteobacteria. In contrast to the direct use of FBA, SteadyCom is able to predict the change in species abundance in response to changes in diets with minimal additional imposed constraints on the model. By randomizing the uptake rates of microbes, an abundance profile with a good agreement to experimental gut microbiota is inferred. SteadyCom provides an important step towards the cross-cutting task of predicting the composition of a microbial community in a given environment.

  18. Dynamic fluid connectivity during steady-state multiphase flow in a sandstone.

    Science.gov (United States)

    Reynolds, Catriona A; Menke, Hannah; Andrew, Matthew; Blunt, Martin J; Krevor, Samuel

    2017-08-01

    The current conceptual picture of steady-state multiphase Darcy flow in porous media is that the fluid phases organize into separate flow pathways with stable interfaces. Here we demonstrate a previously unobserved type of steady-state flow behavior, which we term "dynamic connectivity," using fast pore-scale X-ray imaging. We image the flow of N 2 and brine through a permeable sandstone at subsurface reservoir conditions, and low capillary numbers, and at constant fluid saturation. At any instant, the network of pores filled with the nonwetting phase is not necessarily connected. Flow occurs along pathways that periodically reconnect, like cars controlled by traffic lights. This behavior is consistent with an energy balance, where some of the energy of the injected fluids is sporadically converted to create new interfaces.

  19. Dynamic fluid connectivity during steady-state multiphase flow in a sandstone

    Science.gov (United States)

    Reynolds, Catriona A.; Menke, Hannah; Andrew, Matthew; Blunt, Martin J.; Krevor, Samuel

    2017-08-01

    The current conceptual picture of steady-state multiphase Darcy flow in porous media is that the fluid phases organize into separate flow pathways with stable interfaces. Here we demonstrate a previously unobserved type of steady-state flow behavior, which we term “dynamic connectivity,” using fast pore-scale X-ray imaging. We image the flow of N2 and brine through a permeable sandstone at subsurface reservoir conditions, and low capillary numbers, and at constant fluid saturation. At any instant, the network of pores filled with the nonwetting phase is not necessarily connected. Flow occurs along pathways that periodically reconnect, like cars controlled by traffic lights. This behavior is consistent with an energy balance, where some of the energy of the injected fluids is sporadically converted to create new interfaces.

  20. Evaluation of Impulse Unloading Efficiency Pertaining to APS Power Block Turbine for Higher Dynamic Steadiness

    Directory of Open Access Journals (Sweden)

    Yu. Filipchik

    2012-01-01

    Full Text Available The paper considers the influence of impulse unloading of APS power block turbine on its dynamic steadiness. The performed calculations while simulating four various impulse turbine characteristics have shown that the highest effect is obtained while characteristics of APS power block turbine are close to the characteristics of a steam turbine K-300/240. It has been established that an application of standard time interval for emergency automation startup and existing delay in the operation of electro-hydraulic transformer do not allow to influence on acceleration area and the positive effect due to load shedding is reached only due to an increase of braking site. While decreasing time period for control signal supply from 0,2 sec to 0,1 sec it is possible to increase steadiness by 10 %  for impulse characteristics of APS power blocks and by 39,9–42,6 % – for characteristics of the turbine K-300/240.

  1. Raman lidar measurements of water vapor and aerosols during the atmospheric radiation measurement (ARM) remote clouds sensing (RCS) intensive observation period (IOP)

    Energy Technology Data Exchange (ETDEWEB)

    Melfi, S.H.; Starr, D.O`C.; Whiteman, D. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)] [and others

    1996-04-01

    The first Atmospheric Radiation Measurement (ARM) remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) site. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program.

  2. De kwaliteit van ondiep en middeldiep grond-water in Nederland in het jaar 2000 en verandering daarvan in de periode 1984-2000

    NARCIS (Netherlands)

    Reijnders HFR; Drecht G van; Prins HF; Bronswijk JJB; Boumans LJM; LDL

    2004-01-01

    This report documents the quality of shallow (about 10 m below surface level) and medium-deep (about 25 m below surface level) groundwater in the Netherlands in the 1984-2000 period. Observations were grouped according to groups of eco-district areas. The observed concentrations were compared with

  3. Computational issues of solving the 1D steady gradually varied flow equation

    Directory of Open Access Journals (Sweden)

    Artichowicz Wojciech

    2014-09-01

    Full Text Available In this paper a problem of multiple solutions of steady gradually varied flow equation in the form of the ordinary differential energy equation is discussed from the viewpoint of its numerical solution. Using the Lipschitz theorem dealing with the uniqueness of solution of an initial value problem for the ordinary differential equation it was shown that the steady gradually varied flow equation can have more than one solution. This fact implies that the nonlinear algebraic equation approximating the ordinary differential energy equation, which additionally coincides with the wellknown standard step method usually applied for computing of the flow profile, can have variable number of roots. Consequently, more than one alternative solution corresponding to the same initial condition can be provided. Using this property it is possible to compute the water flow profile passing through the critical stage.

  4. Steady state and a general scale law of deformation

    Science.gov (United States)

    Huang, Yan

    2017-07-01

    Steady state deformation has been characterized based on the experimental results for dilute single-phase aluminium alloys. It was found that although characteristic properties such as flow stress and grain size remained constant with time, a continuous loss of grain boundaries occurred as an essential feature at steady state. A physical model, which takes into account the activity of grain boundary dislocations, was developed to describe the kinetics of steady state deformation. According to this model, the steady state as a function of strain rate and temperature defines the limit of the conventional grain size and strength relationship, i.e., the Hall-Petch relation holds when the grain size is larger than that at the steady state, and an inverse Hall-Petch relation takes over if grain size is smaller than the steady state value. The transition between the two relationships relating grain size and strength is a phenomenon that depends on deformation conditions, rather than an intrinsic property as generally perceived. A general scale law of deformation is established accordingly.

  5. Water

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-08-01

    Full Text Available , and of the remaining 2,5 percent, some 70 percent is frozen in the polar caps and around 30 percent is present as soil moisture or in underground aquifers. Less than 1 percent is thus accessible for direct use by humans, animals and plants. Consequently... be serviced with harvested water and/or grey water. Conserve and reuse cooling tower water by using efficient systems and strategies. Avoid ?once-through systems? commonly used for evaporation coolers, ice makers, hydraulic equipment, and air compressors...

  6. Changes in carbon and nitrogen allocation, growth and grain yield induced by arbuscular mycorrhizal fungi in wheat (Triticum aestivum L.) subjected to a period of water deficit

    DEFF Research Database (Denmark)

    Zhou, Qin; Ravnskov, Sabine; Jiang, Dong

    2015-01-01

    Drought is a major abiotic factor limiting agricultural crop production. One of the effective ways to increase drought resistance in plants could be to optimize the exploitation of symbiosis with arbuscular mycorrhizal fungi (AMF). Hypothesizing that alleviation of water deficits by AMF in wheat...... increased plant height in both cultivars. AMF also increased biomass and grain yield in ‘1110’ but not in ‘Vinjett’. The results showed that the improvements in growth and yield were the results of AMF-mediated increases in photosynthesis during drought stress and that the alleviating effect of AMF depended...... will help maintain photosynthetic carbon-use, we studied the role of AMF on gas-exchange, light-use efficiencies, carbon/nitrogen ratios and growth and yield parameters in the contrasting wheat (Triticum aestivum L.) cultivars ‘Vinjett’ and ‘1110’ grown with/without AMF symbiosis. Water deficits applied...

  7. Water Quality Conditions Monitored at the Corps’ Garrison Project in North Dakota during the 3-Year Period 2003 through 2005

    Science.gov (United States)

    2006-07-01

    of the lake are eutrophic to moderately eutrophic . The phytoplankton community of Lake Sakakawea was dominated by diatoms, with only minor “blooms...aerobic or oxic (i.e., oxygen-containing) environment. Oxygen is produced by aquatic plants (phytoplankton and macrophytes ) and is consumed by aquatic...increases when aquatic plants (phytoplankton or macrophytes ) remove CO2 from the water to form organic matter through photosynthesis during the day

  8. Analysis of the return period and correlation between the reservoir-induced seismic frequency and the water level based on a copula: A case study of the Three Gorges reservoir in China

    Science.gov (United States)

    Liu, Xiaofei; Zhang, Qiuwen

    2016-11-01

    Studies have considered the many factors involved in the mechanism of reservoir seismicity. Focusing on the correlation between reservoir-induced seismicity and the water level, this study proposes to utilize copula theory to build a correlation model to analyze their relationships and perform the risk analysis. The sequences of reservoir induced seismicity events from 2003 to 2011 in the Three Gorges reservoir in China are used as a case study to test this new methodology. Next, we construct four correlation models based on the Gumbel, Clayton, Frank copula and M-copula functions and employ four methods to test the goodness of fit: Q-Q plots, the Kolmogorov-Smirnov (K-S) test, the minimum distance (MD) test and the Akaike Information Criterion (AIC) test. Through a comparison of the four models, the M-copula model fits the sample better than the other three models. Based on the M-copula model, we find that, for the case of a sudden drawdown of the water level, the possibility of seismic frequency decreasing obviously increases, whereas for the case of a sudden rising of the water level, the possibility of seismic frequency increasing obviously increases, with the former being greater than the latter. The seismic frequency is mainly distributed in the low-frequency region (Y ⩽ 20) for the low water level and in the middle-frequency region (20 80) is the least likely. For the conditional return period, it can be seen that the period of the high-frequency seismicity is much longer than those of the normal and medium frequency seismicity, and the high water level shortens the periods.

  9. Water

    Directory of Open Access Journals (Sweden)

    E. Sanmuga Priya

    2017-05-01

    Full Text Available Phytoremediation through aquatic macrophytes treatment system (AMATS for the removal of pollutants and contaminants from various natural sources is a well established environmental protection technique. Water hyacinth (Eichhornia crassipes, a worst invasive aquatic weed has been utilised for various research activities over the last few decades. The biosorption capacity of the water hyacinth in minimising various contaminants present in the industrial wastewater is well studied. The present review quotes the literatures related to the biosorption capacity of the water hyacinth in reducing the concentration of dyestuffs, heavy metals and minimising certain other physiochemical parameters like TSS (total suspended solids, TDS (total dissolved solids, COD (chemical oxygen demand and BOD (biological oxygen demand in textile wastewater. Sorption kinetics through various models, factors influencing the biosorption capacity, and role of physical and chemical modifications in the water hyacinth are also discussed.

  10. Potentialities of steady-state and transient thermography in breast tumour depth detection: A numerical study.

    Science.gov (United States)

    Amri, Amina; Pulko, Susan Helen; Wilkinson, Anthony James

    2016-01-01

    Breast thermography still has inherent limitations that prevent it from being fully accepted as a breast screening modality in medicine. The main challenges of breast thermography are to reduce false positive results and to increase the sensitivity of a thermogram. Further, it is still difficult to obtain information about tumour parameters such as metabolic heat, tumour depth and diameter from a thermogram. However, infrared technology and image processing have advanced significantly and recent clinical studies have shown increased sensitivity of thermography in cancer diagnosis. The aim of this paper is to study numerically the possibilities of extracting information about the tumour depth from steady state thermography and transient thermography after cold stress with no need to use any specific inversion technique. Both methods are based on the numerical solution of Pennes bioheat equation for a simple three-dimensional breast model. The effectiveness of two approaches used for depth detection from steady state thermography is assessed. The effect of breast density on the steady state thermal contrast has also been studied. The use of a cold stress test and the recording of transient contrasts during rewarming were found to be potentially suitable for tumour depth detection during the rewarming process. Sensitivity to parameters such as cold stress temperature and cooling time is investigated using the numerical model and simulation results reveal two prominent depth-related characteristic times which do not strongly depend on the temperature of the cold stress or on the cooling period. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  11. Arc plasma generator of atomic driver for steady-state negative ion source.

    Science.gov (United States)

    Ivanov, A A; Belchenko, Yu I; Davydenko, V I; Ivanov, I A; Kolmogorov, V V; Listopad, A A; Mishagin, V V; Putvinsky, S V; Shulzhenko, G I; Smirnov, A

    2014-02-01

    The paper reviews the results of development of steady-state arc-discharge plasma generator with directly heated LaB6 cathode. This arc-discharge plasma generator produces a plasma jet which is to be converted into an atomic one after recombination on a metallic plate. The plate is electrically biased relative to the plasma in order to control the atom energies. Such an intensive jet of hydrogen atoms can be used in negative ion sources for effective production of negative ions on a cesiated surface of plasma grid. All elements of the plasma generator have an augmented water cooling to operate in long pulse mode or in steady state. The thermo-mechanical stresses and deformations of the most critical elements of the plasma generator were determined by simulations. Magnetic field inside the discharge chamber was optimized to reduce the local power loads. The first tests of the steady-state arc plasma generator prototype have performed in long-pulse mode.

  12. Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

    Science.gov (United States)

    Bazan, Ovandir; Ortiz, Jayme Pinto; Vieira Junior, Francisco Ubaldo; Vieira, Reinaldo Wilson; Antunes, Nilson; Tabacow, Fabio Bittencourt Dutra; Costa, Eduardo Tavares; Petrucci Junior, Orlando

    2013-01-01

    Introduction In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench. Objective To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. Methods To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. ) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. Results It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. Conclusions Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves. PMID:24598950

  13. Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

    Directory of Open Access Journals (Sweden)

    Ovandir Bazan

    2013-12-01

    Full Text Available INTRODUCTION: In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench. OBJECTIVE: To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. METHODS: To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. RESULTS: It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. CONCLUSIONS: Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM is superior to the 21 AJ - 501 model (Master Series. Based on the results, future studies can choose to focus on specific regions of the these valves.

  14. Molecular dynamics modeling of periodic nanostructuring of metals with a short UV laser pulse under spatial confinement by a water layer

    Science.gov (United States)

    Ivanov, D. S.; Blumenstein, A.; Ihlemann, J.; Simon, P.; Garcia, M. E.; Rethfeld, B.

    2017-12-01

    The possibility of material surfaces restructuring on the nanoscale due to ultrashort laser pulses has recently found a number of practical applications. It was found experimentally that under spatial confinement due to a liquid layer atop the surface, one can achieve even finer and cleaner structures as compared to that in air or in vacuum. The mechanism of the materials restructuring under the liquid confinement, however, is not clear and its experimental study is limited by the extreme conditions realized during the intense and localized laser energy deposition that takes place on nanometer spatial and picosecond time-scales. In this theoretical work, we suggest a molecular dynamics-based approach that is capable of simulating the processes of periodic nanostructuring with ultrashort UV laser pulse on metals. The theoretical results of the simulations are directly compared with the experimental data on the same spatial and temporal scales.

  15. Efficient steady-state solver for hierarchical quantum master equations.

    Science.gov (United States)

    Zhang, Hou-Dao; Qiao, Qin; Xu, Rui-Xue; Zheng, Xiao; Yan, YiJing

    2017-07-28

    Steady states play pivotal roles in many equilibrium and non-equilibrium open system studies. Their accurate evaluations call for exact theories with rigorous treatment of system-bath interactions. Therein, the hierarchical equations-of-motion (HEOM) formalism is a nonperturbative and non-Markovian quantum dissipation theory, which can faithfully describe the dissipative dynamics and nonlinear response of open systems. Nevertheless, solving the steady states of open quantum systems via HEOM is often a challenging task, due to the vast number of dynamical quantities involved. In this work, we propose a self-consistent iteration approach that quickly solves the HEOM steady states. We demonstrate its high efficiency with accurate and fast evaluations of low-temperature thermal equilibrium of a model Fenna-Matthews-Olson pigment-protein complex. Numerically exact evaluation of thermal equilibrium Rényi entropies and stationary emission line shapes is presented with detailed discussion.

  16. Fractality in nonequilibrium steady states of quasiperiodic systems

    Science.gov (United States)

    Varma, Vipin Kerala; de Mulatier, Clélia; Žnidarič, Marko

    2017-09-01

    We investigate the nonequilibrium response of quasiperiodic systems to boundary driving. In particular, we focus on the Aubry-André-Harper model at its metal-insulator transition and the diagonal Fibonacci model. We find that opening the system at the boundaries provides a viable experimental technique to probe its underlying fractality, which is reflected in the fractal spatial dependence of simple observables (such as magnetization) in the nonequilibrium steady state. We also find that the dynamics in the nonequilibrium steady state depends on the length of the chain chosen: generic length chains harbour qualitatively slower transport (different scaling exponent) than Fibonacci length chains, which is in turn slower than in the closed system. We conjecture that such fractal nonequilibrium steady states should arise in generic driven critical systems that have fractal properties.

  17. Steady state visually evoked potential (SSVEP) topography changes associated with cocoa flavanol consumption.

    Science.gov (United States)

    Camfield, D A; Scholey, A; Pipingas, A; Silberstein, R; Kras, M; Nolidin, K; Wesnes, K; Pase, M; Stough, C

    2012-02-28

    In a randomized, double-blind placebo controlled trial, 63 middle-aged volunteers aged between 40 and 65 years were administered a daily chocolate drink containing 250 mg or 500 mg cocoa flavanols versus a low cocoa flavanol (placebo) drink over a 30-day period. Participants were tested at baseline as well as at the end of the treatment period on a test of Spatial Working Memory. Steady State Probe Topography (SST) was used to assess neurocognitive changes associated with cocoa flavanol supplementation during the completion of the Spatial Working Memory task. SST is an electrophysiological technique which utilizes a 13 Hz diffuse visual flicker in order to generate a steady state visually evoked potential (SSVEP). Changes in the amplitude and phase of the SSVEP response after 30 days were compared between treatment groups. Behavioral measures of accuracy and reaction time were not found to be significantly different between treatment groups, while average SSVEP amplitude and phase differences at a number of posterior parietal and centro-frontal sites were found to be significantly different between groups during memory encoding, the working memory hold period and retrieval. In the absence of significant behavioral effects, these differences in brain activation can be interpreted as evidence of increased neural efficiency in spatial working memory function associated with chronic cocoa flavanol consumption. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Steady-streaming effects on the motion of the cerebrospinal fluid (CSF) in the spinal canal

    Science.gov (United States)

    Lawrence, Jenna; Coenen, Wilfried; Sanchez, Antonio; Lasheras, Juan

    2017-11-01

    With each heart beat the oscillatory blood supply to the rigid cranial vault produces a time-periodic variation of the intracranial pressure that drives the cerebrospinal fluid (CSF) periodically in and out of the compliant spinal canal. We have recently conducted an analysis of this flow-structure interaction problem taking advantage of the small compliance of the dura membrane bounding externally the CSF and of the disparity of length scales associated with the geometry of the subarachnoid space. We have shown in an idealized geometry that the steady-streaming motion associated with this periodic flow, resulting from the nonlinear cumulative effects of convective acceleration, causes a bulk recirculation of CSF inside the spinal canal, which has been observed in many radiological studies. We extend here our study to investigate the possible contribution arising from the flow around the nerve roots protruding from the spinal cord, an effect that was neglected in our previous work. For this purpose, we consider the oscillatory motion around a cylindrical post confined between two parallel plates. For large values of the relevant Strouhal number we find at leading order a harmonic Stokes flow, whereas steady-streaming effects enter in the first-order corrections, which are computed for realistic values of the Womersley number and of the cylinder height-to-radius ratio.

  19. Pre-steady-state Kinetics for Hydrolysis of Insoluble Cellulose by Cellobiohydrolase Cel7A

    DEFF Research Database (Denmark)

    Cruys-Bagger, Nicolaj; Olsen, Jens Elmerdahl; Præstgaard, Eigil

    2012-01-01

    complex, processive hydrolysis, and dissociation, respectively. These kinetic parameters elucidate limiting factors in the cellulolytic process. We concluded, for example, that Cel7A cleaves about four glycosidic bonds/s during processive hydrolysis. However, the results suggest that stalling...... for the exo-acting cellulase Cel7A using amperometric biosensors and an explicit model for processive hydrolysis of cellulose. This analysis allows the identification of a pseudo-steady-state period and quantification of a processivity number as well as rate constants for the formation of a threaded enzyme...

  20. Parallel shooting methods for finding steady state solutions to engine simulation models

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård; Thomsen, Per Grove; Carlsen, Henrik

    2007-01-01

    Parallel single- and multiple shooting methods were tested for finding periodic steady state solutions to a Stirling engine model. The model was used to illustrate features of the methods and possibilities for optimisations. Performance was measured using simulation of an experimental data set...... as test case. A parallel speedup factor of 23 on 33 processors was achieved with multiple shooting. But fast transients at the beginnings of sub intervals caused significant overhead for the multiple shooting methods and limited the best speedup to 3.8 relative to the fastest sequential method: Single...... shooting with reduced dimension of the boundary value problem....

  1. Steady stokes flow with long-range correlations, fractal fourier spectrum, and anomalous transport.

    Science.gov (United States)

    Zaks, Michael A; Straube, Arthur V

    2002-12-09

    We consider viscous two-dimensional steady flows of incompressible fluids past doubly periodic arrays of solid obstacles. In a class of such flows, the autocorrelations for the Lagrangian observables decay in accordance with the power law, and the Fourier spectrum is neither discrete nor absolutely continuous. We demonstrate that spreading of the droplet of tracers in such flows is anomalously fast. Since the flow is equivalent to the integrable Hamiltonian system with 1 degree of freedom, this provides an example of integrable dynamics with long-range correlations, fractal power spectrum, and anomalous transport properties.

  2. Non-equilibrium steady state in the hydro regime

    Energy Technology Data Exchange (ETDEWEB)

    Pourhasan, Razieh [Science Institute, University of Iceland,Dunhaga 5, 107 Reykjavik (Iceland)

    2016-02-01

    We study the existence and properties of the non-equilibrium steady state which arises by putting two copies of systems at different temperatures into a thermal contact. We solve the problem for the relativistic systems that are described by the energy-momentum of a perfect hydro with general equation of state (EOS). In particular, we examine several simple examples: a hydro with a linear EOS, a holographic CFT perturbed by a relevant operator and a barotropic fluid, i.e., P=P(E). Our studies suggest that the formation of steady state is a universal result of the hydro regime regardless of the kind of fluid.

  3. Steady-state propagation of interface corner crack

    DEFF Research Database (Denmark)

    Veluri, Badrinath; Jensen, Henrik Myhre

    2013-01-01

    Steady-state propagation of interface cracks close to three-dimensional corners has been analyzed. Attention was focused on modeling the shape of the interface crack front and calculating the critical stress for steady-state propagation of the crack. The crack propagation was investigated...... field (crack tip) solutions based on the J-integral. The adopted two-dimensional numerical approach for the calculation of fracture mechanical properties was compared with three-dimensional models for quarter-circular and straight sided crack front shapes. A quantitative approach was formulated based...... for propagation and the angle of intersection of the crack front with the free edge....

  4. Time Dependent and Steady Uni-axial Elongational Viscosity

    DEFF Research Database (Denmark)

    Nielsen, Jens K.; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    Here we present measurements of transient and steady uni-axial elongational viscosity, using the Filament Stretching Rheometer1 or FSR1 (see Fig. 1) of the following melts: Four narrow MMD polystyrene (PS) samples with weight-average molar mass Mw in the range of 50k to 390k. Three different bi......-disperse samples, mixed from the narrow MMD PS. Two low-density polyethylene (LDPE) melts (Lupolen 1840D and 3020D). A steady-state viscosity was kept for 1-2.5 Hencky strain units in all measurements....

  5. Electric machines steady state, transients, and design with Matlab

    CERN Document Server

    Boldea, Ion

    2009-01-01

    Part I: Steady StateIntroductionElectric Energy and Electric MachinesBasic Types of Transformers and Electric MachinesLosses and EfficiencyPhysical Limitations and RatingsNameplate RatingsMethods of AnalysisState of the Art and Perspective Electric TransformersAC Coil with Magnetic Core and Transformer Principles Magnetic Materials in EMs and Their LossesElectric Conductors and Their Skin EffectsComponents of Single- and 3-Phase TransformersFlux Linkages and Inductances of Single-Phase TransformersCircuit Equations of Single-Phase Transformers With Core LossesSteady State and Equivalent Circui

  6. Principle of Entropy Maximization for Nonequilibrium Steady States

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2002-01-01

    has a maximum in a steady state with regard to some thermodynamic variables, the matrix of the Onsager phenomenological coefficients becomes diagonal. The theorem requires consistent rules of the coordinate transformations in the non-equilibrium thermodynamics. Such rules are formulated. The results......The goal of this contribution is to find out to what extent the principle of entropy maximization, which serves as a basis for the equilibrium thermodynamics, may be generalized onto non-equilibrium steady states. We prove a theorem that, in the system of thermodynamic coordinates, where entropy...

  7. Emergence of advance waves in a steady-state universe

    Energy Technology Data Exchange (ETDEWEB)

    Hobart, R.H.

    1979-10-01

    In standard Wheeler-Feynman electrodynamics advanced waves from any source are absolutely canceled by the advanced waves from the absorber responding to that source. The present work shows this cancellation fails over cosmic distances in a steady-state universe. A test of the view proposed earlier, in a paper which assumed failure of cancellation ad hoc, that zero-point fluctuations of the electromagnetic field are such emergent advanced waves, is posed. The view entails anomalous slowing of spontaneous transition rates at longer emission wavelengths; available data go against this, furnishing additional argument against the suspect assumption that the universe is steady-state.

  8. Statistical Discrimination of Steady State Shift Damage Localization Metrics

    DEFF Research Database (Denmark)

    Bull, Thomas; Markvart, Morten Kusk; Sekjær, Claus

    2017-01-01

    When inspecting a linear structure subjected to spatially invariant, repeatable excitation, the recently proposed steady state shift damage localization (S3DL) method offers damage localization by mapping a postulated damage pattern to the damage-induced change in the steady state response...... with a cantilevered residential-sized wind turbine blade, which is exposed to a harmonic input and with the output taken as accelerations captured along the blade edges. Damage is manifested as a stiffness change and the damage localization interrogation will be carried out accordingly....

  9. Sand Dunes in Steady Flow at Low Froude Numbers: Dune Height Evolution and Flow Resistance

    DEFF Research Database (Denmark)

    Niemann, S. L.; Fredsøe, Jørgen; Jacobsen, Niels Gjøl

    2011-01-01

    The development of sand dunes in an erodible bed exposed to flowing water is considered using a numerical flow model. The bed is initially given a small perturbation, which is followed in the time domain. Examples are given where a sinusoidal perturbation reaches the fully developed steady...... equilibrium shape. The flow modeling is based on a k-ω turbulence closure. The sediment transport is assumed to be bed-load only, with an avalanche-like movement on the steep dune front. The model is also found capable of predicting the growth in wavelength if the initially prescribed wavelength...

  10. Erratum to: Study on Chloride Ion Penetration Resistance of Rubberized Concrete Under Steady State Condition

    Directory of Open Access Journals (Sweden)

    Md Noor Nurazuwa

    2016-01-01

    In this paper, the effect of crumb rubber, CR as fine aggregate in the concrete to enhance concrete durability against chloride ion diffusion was studied. Chloride ion diffusion in rubberized concrete was tested by migration test under steady state condition. Concrete specimen with water-to-cement ratio of 0.50 was prepared to study the CR effectiveness in comparison with lower water-to-cement ratio. In addition, 10% silica fume, SF was added to provide denser concrete and to understand its effectiveness against chloride ion diffusion. Results showed that chloride transport characteristics were improved by the increasing amount of CR in all mixed due to the fact that CR has the ability to repel water. Meanwhile, rubberized concrete with w/c = 0.35 gave better resistance against chloride ion penetration compared to w/c = 0.50. This was much improved with combination of CR and SF.

  11. Buoyancy-driven convection heat transfer of copper–water nanofluid in a square enclosure under the different periodic oscillating boundary temperature waves

    Directory of Open Access Journals (Sweden)

    Xilian Han

    2015-09-01

    Full Text Available This study investigates natural convective heat transfer of copper–water nanofluids in a square enclosure with alternating temperature at one vertical wall, relatively low temperature at the opposite sidewall and adiabatic at the other walls. The transport equations are solved numerically with finite volume approach using SIMPLEC algorithm. Calculations are performed for nanoparticle volume fractions from 0 to 0.2 and dimensionless amplitude from 0 to 1.0 with consideration of three typical alternating waves (trapezoid wave, sine wave and triangle wave. Results show the utilization of nanoparticles enhances heat transfer and the percentage increase in the time-averaged Nusselt number is around 38% d from ϕ=0 to ϕ=0.2 under the certain conditions. The oscillating waveform has a degree effect on the heat transfer enhancement and the trapezoid wave is more conducive to the enhancement of heat transfer than sine and triangle waves. And the oscillating area is introduced to combine the oscillating waveform and its amplitude and the percentage increase in the time-averaged Nusselt number is around 14.5% from S=0 to S=0.075. In the end, the regression equation about the time-averaged Nusselt number is obtained as parameters of the solid volume fraction and the oscillating area.

  12. The Assessment of Total Energy Expenditure During a 14-Day In-Season Period of Professional Rugby League Players Using the Doubly Labelled Water Method.

    Science.gov (United States)

    Morehen, James Cameron; Bradley, Warren Jeremy; Clarke, Jon; Twist, Craig; Hambly, Catherine; Speakman, John Roger; Morton, James Peter; Close, Graeme Leonard

    2016-10-01

    Rugby League is a high-intensity collision sport competed over 80 min. Training loads are monitored to maximize recovery and assist in the design of nutritional strategies although no data are available on the total energy expenditure (TEE) of players. We therefore assessed resting metabolic rate (RMR) and TEE in six Super League players over 2 consecutive weeks in-season including one game per week. Fasted RMR was assessed followed by a baseline urine sample before oral administration of a bolus dose of hydrogen (deuterium (2)H) and oxygen ((18)O) stable isotopes in the form of water ((2)H2(18)O). Every 24 hr thereafter, players provided urine for analysis of TEE via DLW method. Individual training load was quantified using session rating of perceived exertion (sRPE) and data were analyzed using magnitude-based inferences. There were unclear differences in RMR between forwards and backs (7.7 ± 0.5 cf. 8.0 ± 0.3 MJ, respectively). Indirect calorimetry produced RMR values most likely lower than predictive equations (7.9 ± 0.4 cf. 9.2 ± 0.4 MJ, respectively). A most likely increase in TEE from Week 1 to 2 was observed (17.9 ± 2.1 cf. 24.2 ± 3.4 MJ) explained by a most likelyincrease in weekly sRPE (432 ± 19 cf. 555 ± 22 AU), respectively. The difference in TEE between forward and backs was unclear (21.6 ± 4.2 cf. 20.5 ± 4.9 MJ, respectively). We report greater TEE than previously reported in rugby that could be explained by the ability of DLW to account for all match and training-related activities that contributes to TEE.

  13. Practical error analysis of the quasi-steady-state approximation ...

    African Journals Online (AJOL)

    The Quasi-Steady-State Approximation (QSSA) is a method of getting approximate solutions to differential equations, developed heuristically in biochemistry early this century. It can produce acceptable and important results even when formal analytic and numerical procedures fail. It has become associated with singular ...

  14. The effectiveness of the Auditory Steady State Response in ...

    African Journals Online (AJOL)

    This paper aims to provide a review of the emerging Auditory Steady State Response in light of existing procedures for diagnosis of hearing loss in infants. Determining the type, degree, and configuration of hearing loss in infants is a challenge requiring sophisticated electrophysiological equipment of which Auditory ...

  15. Forced Sex among Married or Steady Partners in Uganda

    African Journals Online (AJOL)

    Erah

    Research objectives were to understand the relationship between sexual, domestic and civil violence and the transmission of. HIV/AIDS in Uganda. The focus of this paper is on forced marital sex within the context of Ugandan marital and steady partner relations. Qualitative unstructured interviews were conducted in focus ...

  16. Haematological values in sickle cell anaemia in steady state and ...

    African Journals Online (AJOL)

    occlusive crisis in Benin City, Nigeria. ... Annals of African Medicine ... Method: A prospective study of 200 patients (81.3%) in steady state, 46 patients (18.7%) during vaso-occlusive crisis (VOC) and 84 control subjects seen between August 2001 ...

  17. Classical orbital paramagnetism in non-equilibrium steady state

    Indian Academy of Sciences (India)

    58

    Abstract. We report the results of our numerical simulation of classical-dissipative dynamics of a charged particle subjected to a non-markovian stochastic forcing. We find that the system develops a steady-state orbital magnetic moment in the presence of a static magnetic field. Very significantly, the sign of the orbital ...

  18. Stabilizing the border steady-state solution of two interacting ...

    African Journals Online (AJOL)

    In this paper, we have successfully developed a feedback control which has been used to stabilize an unstable steady-state solution (0, 3.3534). This convergence has occurred when the values of the final time are 190, 200, 210 and 220 which corresponds to the scenario when the value of the step length of our simulation ...

  19. Ecological marketing as instrument of steady development providing

    Directory of Open Access Journals (Sweden)

    I.V. Zamula

    2016-07-01

    Full Text Available Anthropogenic influence upon environment and its results cause ecological disbalance of a natural system, destroy of biological connection between a human being and nature. That’s why it’s necessary to protect environment from pollution. To realize this task we have to involve some economical sciences as well. Consequently, our researches are directed to the determination of the place of ecological marketing so that an enterprise could reach the principles of the concept of steady development through the harmonization of interests of producers of goods concerning to the receiving of desirable income amount, consumers concerning to satisfaction of their needs and a society as a whole about reaching a steady development. The article determines the tasks of ecological marketing as an instrument for providing the realization of principles of the steady development concept paying special attention to its constituents such as economical, ecological, and social. The author determines the advantages of implementation of the ecological marketing which allows to get definite competitive advantages at the market and create a positive image of its trade mark and its produce among customers. It is proved that the maximum synthesis of interests of economics and ecology is one of the ways of biosphere protection and reaching a steady development of all the countries and a society as a whole.

  20. The Asymptotic Solution for the Steady Variable-Viscosity Free ...

    African Journals Online (AJOL)

    Under an arbitrary time-dependent heating of an infinite vertical plate (or wall), the steady viscosity-dependent free convection flow of a viscous incompressible fluid is investigated. Using the asymptotic method of solution on the governing equations of motion and energy, the resulting Ordinary differential equations were ...

  1. Dark Entangled Steady States of Interacting Rydberg Atoms

    DEFF Research Database (Denmark)

    Dasari, Durga; Mølmer, Klaus

    2013-01-01

    their short-lived excited states lead to rapid, dissipative formation of an entangled steady state. We show that for a wide range of physical parameters, this entangled state is formed on a time scale given by the strengths of coherent Raman and Rabi fields applied to the atoms, while it is only weakly...

  2. Steady States of the Parametric Rotator and Pendulum

    Science.gov (United States)

    Bouzas, Antonio O.

    2010-01-01

    We discuss several steady-state rotation and oscillation modes of the planar parametric rotator and pendulum with damping. We consider a general elliptic trajectory of the suspension point for both rotator and pendulum, for the latter at an arbitrary angle with gravity, with linear and circular trajectories as particular cases. We treat the…

  3. Steady traffic scheduler for internet video traffic across large delay ...

    African Journals Online (AJOL)

    Steady traffic scheduler for internet video traffic across large delay networks. O.E. Ojo, A.O. Oluwatope, I.T. Arowobusoye. Abstract. No Abstract. Keywords: Computer Networks, Multimedia Networking, TCP and Large-Delay Networks. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

  4. Dispersive and steady-state recombination in organic disordered semiconductors

    Science.gov (United States)

    Hofacker, Andreas; Neher, Dieter

    2017-12-01

    Charge carrier recombination in organic disordered semiconductors is strongly influenced by the thermalization of charge carriers in the density of states (DOS). Measurements of recombination dynamics, conducted under transient or steady-state conditions, can easily be misinterpreted when a detailed understanding of the interplay of thermalization and recombination is missing. To enable adequate measurement analysis, we solve the multiple-trapping problem for recombining charge carriers and analyze it in the transient and steady excitation paradigm for different DOS distributions. We show that recombination rates measured after pulsed excitation are inherently time dependent since recombination gradually slows down as carriers relax in the DOS. When measuring the recombination order after pulsed excitation, this leads to an apparent high-order recombination at short times. As times goes on, the recombination order approaches an asymptotic value. For the Gaussian and the exponential DOS distributions, this asymptotic value equals the recombination order of the equilibrated system under steady excitation. For a more general DOS distribution, the recombination order can also depend on the carrier density, under both transient and steady-state conditions. We conclude that transient experiments can provide rich information about recombination in and out of equilibrium and the underlying DOS occupation provided that consistent modeling of the system is performed.

  5. Steady hydromagnetic Couette flow in a rotating system with ...

    African Journals Online (AJOL)

    Steady hydromagnetic Couette flow of class-II of a viscous incompressible electrically conducting fluid in a rotating system with non-conducting walls is studied. Exact solution of the governing equations is obtained in closed form. Expressions for the shear stress at the lower and upper plates due to primary and secondary ...

  6. Exact results on the steady state of a hopping model

    Science.gov (United States)

    Zhang, M. Q.

    1987-03-01

    A hopping model described by Katz, Lebowitz, and Spohn [J. Stat. Phys. 34, 497 (1983)] and by Valles and Marro [J. Stat. Phys. 43, 441 (1986)] is studied analytically for small lattice systems. The dependence of the nonequilibrium steady state on various parameters and transition rate functions is obtained exactly. The results are compared with simulations on large systems.

  7. Correlates of Steady-State Haematocrit and Hepatosplenomegaly in ...

    African Journals Online (AJOL)

    Backgroup: Sickle cell disease is a common genetic disorder in Nigeria. Objectives: To determine the steady state haematocrit, liver size and spleen size in children with sickle cell disease and the factors that influence them. Methods: This was a retrospective study of children with sickle cell disorders who attended the ...

  8. Steady magnetohydrodynamic radiating flow past a vertical porous ...

    African Journals Online (AJOL)

    Approximate solutions to the coupled non-linear equations governing the steady velocity, temperature, skin friction and rate of heat transfer are obtained invoking a perturbative series expansion in terms of the Eckert number Ec, since the Eckert, number Ec for all incompressible flows is small. We notice that the rate of heat ...

  9. Steady shear viscosity of stirred yoghurts with varying ropiness

    NARCIS (Netherlands)

    van Marle, M.E.; van Marle, M.E.; van den Ende, Henricus T.M.; de Kruif, C.G.; de Kruif, C.G.; Mellema, J.

    1999-01-01

    Stirred yogurt was viewed as a concentrated dispersion of aggregates consisting of protein particles. The steady-shear behavior of three types of stirred yogurt with varying ropiness was investigated experimentally. To describe the shear-dependent viscosity, a microrheological model was used which

  10. Steady bipartite coherence induced by non-equilibrium environment

    Science.gov (United States)

    Huangfu, Yong; Jing, Jun

    2018-01-01

    We study the steady state of two coupled two-level atoms interacting with a non-equilibrium environment that consists of two heat baths at different temperatures. Specifically, we analyze four cases with respect to the configuration about the interactions between atoms and heat baths. Using secular approximation, the conventional master equation usually neglects steady-state coherence, even when the system is coupled with a non-equilibrium environment. When employing the master equation with no secular approximation, we find that the system coherence in our model, denoted by the off-diagonal terms in the reduced density matrix spanned by the eigenvectors of the system Hamiltonian, would survive after a long-time decoherence evolution. The absolute value of residual coherence in the system relies on different configurations of interaction channels between the system and the heat baths. We find that a large steady quantum coherence term can be achieved when the two atoms are resonant. The absolute value of quantum coherence decreases in the presence of additional atom-bath interaction channels. Our work sheds new light on the mechanism of steady-state coherence in microscopic quantum systems in non-equilibrium environments.

  11. Anaerobic digester bioaugmentation influences quasi steady state performance and microbial community.

    Science.gov (United States)

    Venkiteshwaran, K; Milferstedt, K; Hamelin, J; Zitomer, D H

    2016-11-01

    Nine anaerobic digesters, each seeded with biomass from a different source, were operated identically and their quasi steady state function was compared. Subsequently, digesters were bioaugmented with a methanogenic culture previously shown to increase specific methanogenic activity. Before bioaugmentation, different seed biomass resulted in different quasi steady state function, with digesters clustering into three groups distinguished by methane (CH4) production. Digesters with similar functional performance contained similar archaeal communities based on clustering of Illumina sequence data of the V4V5 region of the 16S rRNA gene. High CH4 production correlated with neutral pH and high Methanosarcina abundance, whereas low CH4 production correlated to low pH as well as high Methanobacterium and DHVEG 6 family abundance. After bioaugmentation, CH4 production from the high CH4 producing digesters transiently increased by 11 ± 3% relative to non-bioaugmented controls (p bioaugmentation was correlated to increased relative abundance of Methanosaeta and Methaospirillum originating from the bioaugment culture. In conclusion, different anaerobic digester seed biomass can result in different quasi steady state CH4 production, SCOD removal, pH and effluent VFA concentration in the timeframe studied. The bioaugmentation employed can result in a period of increased methane production. Future research should address extending the period of increased CH4 production by employing pH and VFA control concomitant with bioaugmentation, developing improved bioaugments, or employing a membrane bioreactor to retain the bioaugment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. THE IMPACTS OF FASTING PERIODS ON FOOD INTAKE, GROWTH RATE, COMPENSATORY GROWTH, AND EFFICIENCY OF FEED UTILIZATION IN BLUE TILAPIA (Oreochromis aureus REARED IN BRACKISH WATER PONDS

    Directory of Open Access Journals (Sweden)

    Priadi Setyawan

    2012-12-01

    Full Text Available Blue tilapia (Oreochromis aureus has known as euryhaline species refers to wide range of salinity tolerance. The pure population or hybrid with other strain of tilapia can be a good candidate in marginal coastal land use. Tilapia is the most important aquaculture species in Indonesia. Refers to FAO 2010, Indonesia is the third biggest of tilapia production after China and Egypt. One of the main problems in aquaculture is their feed as the major cost in fish farming. Various techniques had carried out to reduce of feed cost such as improving fish quality, sex reversal and feed management. This research aimed to determine of compensatory growth in tilapia as one technique in feed management. Fry obtained from natural spawning in freshwater pond. Acclimatization in 20 ppt made in aquarium for 4 days after one month reared in hapas. Fish reared in 2 m x 1 m hapas with five treatments and three replications. This research had conducted at brackish water pond in Yogyakarta. The treatments is A: one day fasting and six days feeding (1/6, B: 2/5, C: 3/4, D: 4/3 and E is control. Results showed that the biggest of average weight gain is treatment of E (68.36 g followed by A (66.38 g, B (62.44 g, C (43.56 g, and D (27.30 g respectively. One-way ANOVAs analysis with 95% of interval confidences continued with Tukey’s Pairwaise comparison showed that nothing significant different between E, A, and B. The biggest of daily growth rate and specific growth rate is E (0.75 g/day and 4.68 %bw/day followed by A (0.73 g/day and 4.65 %bw/day; B (0.69 g/day and 4.58 %bw/day; C (0.48 g/day and 4.18% bw/day and D (0.29 g/day and 3.65% bw/day respectively. Survival rate of A is 73.00% followed by E. 72.00%, C. 71.00%, D. 69.69%, and B. 67.00% respectively. Feed conversion ratio of D is 0.83 followed by C (0.87, B (0.98, A (1.16, and E (1.41. Food efficiency ratio of D is 127.06% followed by C (118.75%, B (106.09%, A (88.87%, and E (73.38%. These

  13. A steady-state and pre-steady-state kinetics study of the tungstoenzyme formaldehyde ferredoxin oxidoreductase from Pyrococcus furiosus

    NARCIS (Netherlands)

    Bol, E.; Broers, N.J.; Hagen, W.R.

    2007-01-01

    Formaldehyde ferredoxin oxidoreductase from Pyrococcus furiosus is a homotetrameric protein with onetungstodipterin and one [4Fe–4S] cubane per 69-kDa subunit. The enzyme kinetics have been studied understeady-state conditions at 80 C and pre-steady state conditions at 50 C, in the latter case via

  14. 'Memory' and sustention of microdischarges in a steady-state DBD: volume plasma or surface charge?

    Science.gov (United States)

    Akishev, Yuri; Aponin, Gregory; Balakirev, Anton; Grushin, Mikhail; Karalnik, Vladimir; Petryakov, Alexander; Trushkin, Nikolay

    2011-04-01

    The results of a numerical study on the spatio-temporal behavior of transient microdischarges (MDs) in a steady-state dielectric barrier discharge (DBD) excited by a sinusoidal voltage are presented. MDs have a spatial 'memory'—every subsequent MD appears at exactly the same location occupied by the MD at the preceding half-period (HP). In the majority of cases each MD appears at its location only once during every HP. For such a case, the memory effect is not attributed to the residual surface charge deposited by the preceding MD but determined by the residual MD plasma column shunting the gap right up to the beginning of the next HP. In contrast to good memory in space, each individual MD has a large scatter with time in its appearance within every HP, i.e. there is no 'memory' concerning the phase of an applied voltage. This MD jittering within the period is attributed to the stochastic nature of partial surface breakdowns around the bases of the MD plasma column. Numerical calculations show that surface breakdown provides an MD current splash at every HP. Hence, in the steady-state DBD, the volume plasma is responsible for the existence of MD spatial 'memory' (i.e. where the MD appears), and the deposited surface charge is responsible for MD jittering in time (i.e. when the MD appears). Hot topic report presented at the 20th ESCAMPIG, 13-17 July 2010, Novi Sad, Serbia.

  15. Steady state RF facility for testing ITER ICRH RF contact component

    Energy Technology Data Exchange (ETDEWEB)

    Argouarch, A., E-mail: arnaud.argouarch@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Bamber, R. [Euratom/CCFE Association, Culham Science Centre, Abingdon, Oxon, OX143DB (United Kingdom); Bernard, J.M.; Delaplanche, J.M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Durodié, F. [Laboratory for Plasmas Physics, 1000 Brussels (Belgium); Larroque, S.; Lecomte, P.; Lombard, G.; Hatchressian, J.C.; Mollard, P.; Mouyon, D.; Pagano, M.; Patterlini, J.C.; Rasio, S.; Soler, B.; Toulouse, L.; Thouvenin, D.; Verger, J.M.; Vigne, T.; Volpe, R. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2013-10-15

    After the installation and commissioning of the TITAN [1,2], test facility, a key element – the T resonator – was assembled in order to facilitate testing components at high RF voltages and currents. This work is within the CEA roadmap for testing ITER ICRH components in a relevant environment. Several components of the future ITER ICRH antenna have been targeted. The embedded RF contact within the ITER ICRH antenna appeared as a critical component for antenna performance, requiring extensive R and D. Therefore, CEA has proposed and subsequently prepared a platform to test and validate the anticipated RF contact. A steady state resonator with active water cooling has been manufactured and assembled within the TITAN facility, including a hot pressurized water loop. The program consists of testing the contact at 2.25 kA and 62 MHz in steady state conditions. Sliding tests are also performed at high temperature and vacuum to understand component aging, including wear. The equipment installed is consistent with that required to test an ITER ICRH extensively.

  16. Absent menstrual periods - primary

    Science.gov (United States)

    Primary amenorrhea; No periods - primary; Absent periods - primary; Absent menses - primary; Absence of periods - primary ... nutrition Tumors In many cases, the cause of primary amenorrhea is not known.

  17. Steady State Dynamic Operating Behavior of Universal Motor

    Directory of Open Access Journals (Sweden)

    Muhammad Khan Burdi

    2015-01-01

    Full Text Available A detailed investigation of the universal motor is developed and used for various dynamic steady state and transient operating conditions of loads. In the investigation, output torque, motor speed, input current, input/output power and efficiency are computed, compared and analyzed for different loads. While this paper discusses the steady-state behavior of the universal motor, another companion paper, ?Transient dynamic behavior of universal motor?, will discuss its transient behavior in detail. A non-linear generalized electric machine model of the motor is considered for the analysis. This study was essential to investigate effect of output load on input current, power, speed and efficiency of the motor during operations. Previously such investigation is not known

  18. Non-equilibrium steady states in supramolecular polymerization

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Sato, Akihiro; Hermans, Thomas M.

    2017-06-01

    Living systems use fuel-driven supramolecular polymers such as actin to control important cell functions. Fuel molecules like ATP are used to control when and where such polymers should assemble and disassemble. The cell supplies fresh ATP to the cytosol and removes waste products to sustain steady states. Artificial fuel-driven polymers have been developed recently, but keeping them in sustained non-equilibrium steady states (NESS) has proven challenging. Here we show a supramolecular polymer that can be kept in NESS, inside a membrane reactor where ATP is added and waste removed continuously. Assembly and disassembly of our polymer is regulated by phosphorylation and dephosphorylation, respectively. Waste products lead to inhibition, causing the reaction cycle to stop. Inside the membrane reactor, however, waste can be removed leading to long-lived NESS conditions. We anticipate that our approach to obtain NESS can be applied to other stimuli-responsive materials to achieve more life-like behaviour.

  19. Steady streamwise transpiration control in turbulent pipe flow

    CERN Document Server

    Gómez, F; Rudman, M; Sharma, AS; McKeon, BJ

    2016-01-01

    A study of the the main features of low- and high amplitude steady streamwise wall transpiration applied to pipe flow is presented. The effect of the two transpiration parameters, amplitude and wavenumber, on the flow have been investigated by means of direct numerical simulation at a moderate turbulent Reynolds number. The behaviour of the three identified mechanisms that act in the flow: modification of Reynolds shear stress, steady streaming and generation of non-zero mean streamwise gradients, have been linked to the transpiration parameters. The observed trends have permitted the identification of wall transpiration configurations able to reduce or increase the overall flow rate in -36.1% and 19.3% respectively. A resolvent analysis has been carried out to obtain a description of the reorganization of the flow structures induced by the transpiration.

  20. Extending Molecular Theory to Steady-State Diffusing Systems

    Energy Technology Data Exchange (ETDEWEB)

    FRINK,LAURA J. D.; SALINGER,ANDREW G.; THOMPSON,AIDAN P.

    1999-10-22

    Predicting the properties of nonequilibrium systems from molecular simulations is a growing area of interest. One important class of problems involves steady state diffusion. To study these cases, a grand canonical molecular dynamics approach has been developed by Heffelfinger and van Swol [J. Chem. Phys., 101, 5274 (1994)]. With this method, the flux of particles, the chemical potential gradients, and density gradients can all be measured in the simulation. In this paper, we present a complementary approach that couples a nonlocal density functional theory (DFT) with a transport equation describing steady-state flux of the particles. We compare transport-DFT predictions to GCMD results for a variety of ideal (color diffusion), and nonideal (uphill diffusion and convective transport) systems. In all cases excellent agreement between transport-DFT and GCMD calculations is obtained with diffusion coefficients that are invariant with respect to density and external fields.

  1. Performance of a quasi-steady model for hovering hummingbirds

    Directory of Open Access Journals (Sweden)

    Jialei Song

    2015-01-01

    Full Text Available A quasi-steady model describing aerodynamics of hovering Ruby-throated hummingbirds is presented to study extent of the low-order model in representing the flow physics of the bird and also to separately quantify the forces from the translational, rotational, and acceleration effects. Realistic wing kinematics are adopted and the model is calibrated against computational fluid dynamics (CFD simulations of a corresponding revolving-wing model. The results show that the quasi-steady model is able to predict overall lift production reasonably well but fails to capture detailed force oscillations. The downstroke–upstroke asymmetry is consistent with that in the previous CFD study. Further analysis shows that significant rotational force is produced during mid-stroke rather than wing reversal.

  2. Theoretical analysis of steady state operating forces in control valves

    Directory of Open Access Journals (Sweden)

    Basavaraj Hubballi

    2018-01-01

    Full Text Available The controlling components, such as valves are used to regulate controlled fluid power. It is not always possible to calculate valve forces accurately, and with some types of valves even the existence of certain types of forces cannot be predicted with certainty. In many cases, however, the analysis can be made fairly completely and accurately. The assumption of steady state conditions is valid for the valve alone, but transient effects in the rest of the system may be large. These effects are particularly important with regard to the instability of valves, where the system may react on the valve in such a way as to make it squeal or oscillate, sometimes with large amplitude. The origin of the steady state flow force understood from a brief qualitative explanation. The following paper will summarize much of what is known about valve forces in the spool type controlling element.

  3. Evolution of periodicity in periodical cicadas.

    Science.gov (United States)

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  4. Ensuring Steady Operation of Free-Piston Generator

    Directory of Open Access Journals (Sweden)

    Pavel Nemecek

    2006-02-01

    Full Text Available This paper describes Free-Piston Generator (FPG model and its control for achieving steady operation. A FPG is a special type of combustion engine representing a new approach concerning the conversion of the chemical energy of hydrocarbon fuel into electrical energy. Unlike conventional engines, this type of engine does not use a crankshaft, and generates electric energy directly by a linear movement of pistons.

  5. Steady State Stokes Flow Interpolation for Fluid Control

    DEFF Research Database (Denmark)

    Bhatacharya, Haimasree; Nielsen, Michael Bang; Bridson, Robert

    2012-01-01

    — suffer from a common problem. They fail to capture the rotational components of the velocity field, although extrapolation in the normal direction does consider the tangential component. We address this problem by casting the interpolation as a steady state Stokes flow. This type of flow captures...... the rotational components and is suitable for controlling liquid animations where tangential motion is pronounced, such as in a breaking wave...

  6. A stabilised nonconforming finite element method for steady incompressible flows

    Science.gov (United States)

    Huang, Pengzhan; Feng, Xinlong; Liu, Demin

    2012-02-01

    A stabilised nonconforming finite element method for the steady incompressible flow problem with damping based on local Gauss integration is considered in this article. The method combines the nonconforming finite element method with the stabilised strategy. Moreover, the stability and error estimates are analysed. Finally, numerical results are shown to support the developed theory analysis. Compared with some classical, closely related mixed finite element methods, the results of the present method show its better performance than others.

  7. Modulated stagnation-point flow and steady streaming

    Science.gov (United States)

    Merchant, Gregory J.; Davis, Stephen H.

    1989-01-01

    Plane stagnation-point flow is modulated in the free stream so that the velocity components are proportional to K(H) + K cos omega t. Similarity solutions of the Navier-Stokes equations are examined using high-frequency asymptotics for K and K(H) of unit order. Special attention is focused on the steady streaming generated in this flow with strongly non-parallel streamlines.

  8. Cavitation modeling for steady-state CFD simulations

    Science.gov (United States)

    Hanimann, L.; Mangani, L.; Casartelli, E.; Widmer, M.

    2016-11-01

    Cavitation in hydraulic turbomachines is an important phenomenon to be considered for performance predictions. Correct analysis of the cavitation onset and its effect on the flow field while diminishing the pressure level need therefore to be investigated. Even if cavitation often appears as an unsteady phenomenon, the capability to compute it in a steady state formulation for the design and assessment phase in the product development process is very useful for the engineer. In the present paper the development and corresponding application of a steady state CFD solver is presented, based on the open source toolbox OpenFOAM®. In the first part a review of different cavitation models is presented. Adopting the mixture-type cavitation approach, various models are investigated and developed in a steady state CFD RANS solver. Particular attention is given to the coupling between cavitation and turbulence models as well as on the underlying numerical procedure, especially the integration in the pressure- correction step of pressure-based solvers, which plays an important role in the stability of the procedure. The performance of the proposed model is initially assessed on simple cases available in the open literature. In a second step results for different applications are presented, ranging from airfoils to pumps.

  9. Extracting Steady State Components from Synchrophasor Data Using Kalman Filters

    Directory of Open Access Journals (Sweden)

    Farhan Mahmood

    2016-04-01

    Full Text Available Data from phasor measurement units (PMUs may be exploited to provide steady state information to the applications which require it. As PMU measurements may contain errors and missing data, the paper presents the application of a Kalman Filter technique for real-time data processing. PMU data captures the power system’s response at different time-scales, which are generated by different types of power system events; the presented Kalman Filter methods have been applied to extract the steady state components of PMU measurements that can be fed to steady state applications. Two KF-based methods have been proposed, i.e., a windowing-based KF method and “the modified KF”. Both methods are capable of reducing noise, compensating for missing data and filtering outliers from input PMU signals. A comparison of proposed methods has been carried out using the PMU data generated from a hardware-in-the-loop (HIL experimental setup. In addition, a performance analysis of the proposed methods is performed using an evaluation metric.

  10. Ideal MHD Stability of ITER Steady State Scenarios with ITBs

    Energy Technology Data Exchange (ETDEWEB)

    F.M. Poli, C.E. Kessel, S. Jardin, J. Manickam, M. Chance, J. Chen

    2011-07-27

    One of ITER goals is to demonstrate feasibility of continuous operations using non-inductive current drive. Two main candidates have been identified for advanced operations: the long duration, high neutron fluency hybrid scenario and the steady state scenario, both operating at a plasma current lower than the reference ELMy scenario [1][2] to minimize the required current drive. The steady state scenario targets plasmas with current 7-10 MA in the flat-top, 50% of which will be provided by the self-generated, pressure-driven bootstrap current. It has been estimated that, in order to obtain a fusion gain Q > 5 at a current of 9 MA, it should be ΒN > 2.5 and H > 1.5 [3]. This implies the presence of an Internal Transport Barrier (ITB). This work discusses how the stability of steady state scenarios with ITBs is affected by the external heating sources and by perturbations of the equilibrium profiles.

  11. Progress and prospect of true steady state operation with RF

    Science.gov (United States)

    Jacquinot, Jean

    2017-10-01

    Operation of fusion confinement experiments in full steady state is a major challenge for the development towards fusion energy. Critical to achieving this goal is the availability of actively cooled plasma facing components and auxiliary systems withstanding the very harsh plasma environment. Equally challenging are physics issues related to achieving plasma conditions and current drive efficiency required by reactor plasmas. RF heating and current drive systems have been key instruments for obtaining the progress made until today towards steady state. They hold all the records of long pulse plasma operation both in tokamaks and in stellarators. Nevertheless much progress remains to be made in particular for integrating all the requirements necessary for maintaining in steady state the density and plasma pressure conditions of a reactor. This is an important stated aim of ITER and of devices equipped with superconducting magnets. After considering the present state of the art, this review will address the key issues which remain to be solved both in physics and technology for reaching this goal. They constitute very active subjects of research which will require much dedicated experimentation in the new generation of superconducting devices which are now in operation or becoming close to it.

  12. Evaluation of Performance of Five Parallel Biological Water Proce

    Science.gov (United States)

    Vega, Leticia M.; Kerkhof, Lee; McGuinness, Lora; Pickering, Karen

    2004-01-01

    The objective of the work entitled Molecular Characterization of Eubacteria in a Biological Water Processor was to gain an understanding of the microbial diversity and species stability of the consortia that inhabit an anoxic bioreactor and to correlate those factors with functional performance, mechanical reliability, and stability. The evaluation was divided into four studies. During Study 1, replicate biological water processor (BWP) systems were operated to evaluate variability in the microbial diversity over time as a function of the initial consortia used for inoculation of the BWP reactors. Study 2 was designed to investigate the impact of an inoculum source on BWP performance. Study 3 was a modification of Study 2 where the impact of inoculum on BWP performance from inoculation until steady state operations was monitored. In Study 4, the reactors were divided into three different operational periods, based on the operational periods of the integrated water recovery test at the Johnson Space Center (JSC) in 2001.

  13. Sensitivity and specificity of auditory steady-state response testing

    Directory of Open Access Journals (Sweden)

    Camila Maia Rabelo

    2011-01-01

    Full Text Available INTRODUCTION: The ASSR test is an electrophysiological test that evaluates, among other aspects, neural synchrony, based on the frequency or amplitude modulation of tones. OBJECTIVE: The aim of this study was to determine the sensitivity and specificity of auditory steady-state response testing in detecting lesions and dysfunctions of the central auditory nervous system. METHODS: Seventy volunteers were divided into three groups: those with normal hearing; those with mesial temporal sclerosis; and those with central auditory processing disorder. All subjects underwent auditory steady-state response testing of both ears at 500 Hz and 2000 Hz (frequency modulation, 46 Hz. The difference between auditory steady-state response-estimated thresholds and behavioral thresholds (audiometric evaluation was calculated. RESULTS: Estimated thresholds were significantly higher in the mesial temporal sclerosis group than in the normal and central auditory processing disorder groups. In addition, the difference between auditory steady-state response-estimated and behavioral thresholds was greatest in the mesial temporal sclerosis group when compared to the normal group than in the central auditory processing disorder group compared to the normal group. DISCUSSION: Research focusing on central auditory nervous system (CANS lesions has shown that individuals with CANS lesions present a greater difference between ASSR-estimated thresholds and actual behavioral thresholds; ASSR-estimated thresholds being significantly worse than behavioral thresholds in subjects with CANS insults. This is most likely because the disorder prevents the transmission of the sound stimulus from being in phase with the received stimulus, resulting in asynchronous transmitter release. Another possible cause of the greater difference between the ASSR-estimated thresholds and the behavioral thresholds is impaired temporal resolution. CONCLUSIONS: The overall sensitivity of auditory steady

  14. 18 CFR 367.5 - Accounting period.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Accounting period. 367.5 Section 367.5 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... Instructions § 367.5 Accounting period. Each service company must keep its books on a monthly basis so that for...

  15. Hydrodynamic parameters of micro porous media for steady and oscillatory flow: Application to cryocooler regenerators

    Science.gov (United States)

    Cha, Jeesung Jeff

    microporous structures. This is particularly troubling with regards to the regenerator, where friction and thermal non-equilibrium between the fluid and the structure play crucial roles. Little attention has been paid to this issue primarily because of the difficulty of experimental measurements. Multi-dimensional modeling of a regenerator is very complex and requires knowledge about the anisotropic hydrodynamic parameters in various components, in particular the regenerator. In view of the above, this investigation was aimed at: (a) experimental measurement and correlation of the steady and periodic flow directional Darcy permeability and Forchheimer's inertial hydrodynamic parameters for some widely-used regenerator fillers; (b) system-level parametric CFD-based analyses of entire PTC systems; and (c) a preliminary CFD-based assessment of the effect of direct and linear scale-down of current Inertance Tube Pulse Tube Cryocooler (ITPTCs) on their thermal performance. Modular experimental apparatuses were designed and built for the measurement of pressure drops across five different and widely-used regenerator fillers, under steady-state and steady periodic flow conditions. Separate test sections were used so that the pressure drops in axial and lateral directions could be measured. The fillers that were investigated included 325 mesh stainless steel screens, 400 mesh stainless steel screens, sintered 400 mesh stainless steel screens, stainless steel metal foam, and stacked nickel micro-machined disks. The parametric effects that were addressed in the experiments included the porosity in the range of 26.8% to 69.2%, and frequency in the range of 5 Hz to 60 Hz for the periodic flow tests. A CFDassisted method was developed, which allowed for obtaining the directional permeability and Forchheimer coefficients from the experimental data in a rigorous manner and without any arbitrary assumption. Using the Fluent code, parametric CID analyses were performed in which entire ITPTC

  16. Modelling spatial distribution of soil steady state infiltration rate in an urban park (Vingis Parkas, Vilnius, Lithuania)

    Science.gov (United States)

    Pereira, Paulo; Cerda, Artemi; Depellegrin, Daniel; Misiune, Ieva; Bogunovic, Igor; Menchov, Oleksandr

    2016-04-01

    Within the hydrological process, infiltration is a key component as control the partitioning of the rainfall into runoff or soil water (Cerdà, 1997). And the infiltration process is determining the fate of the soil development and the human impact in the soil system (Brevik et al., 2015). On forest soils, the infiltration use to be high due to the macropore flow, which drainages the surface runoff usually generated by the hydrophobic response of soil reach in organic matter (Hewelke et al., 2015) or as a consequence of forest fires (Jordán et al., 2010; Pereira et al., 2014) due to the development of water repellent substances (Mao et al., 2015), which are mainly associated to the ash (Pereira et al., 2014; Pereira et al., 2015). To understand the role the infiltration plays in the soil development and the runoff generation is important, and also is necessary to understand how some factors such as vegetation, crust, stones, litter, mulches… play in the hydrological, erosional and pedological system (Cerdà, 2001; Keesstra, 2007; Liu et al., 2014; Bisantino et al., 2015; Cassinari et al., 2015, Cerdà et al., 2015; Mohawesh et al., 2015; Terribile et al., 2015). The well-know importance of the infiltration process did not resulted in the research on the infiltration on urban areas, although there is where the infiltration is more altered. Water infiltration is extremely important in urbanized areas, since the majority of the surfaces are sealed by concrete, asphalt and other materials. Soil sealing increases exponentially the impacts of flash floods and reduces soil infiltration capacity. This decreases importantly one of the most important services provided by soil: water storage and infiltration. In this context, the existence of green areas and urban parks are of major importance to mitigate the impact of human settlements in soil water infiltration. The aim of this work is to assess the spatial distribution of steady-state soil water infiltration in the

  17. Current status and prospect of plasma control system for steady-state operation on QUEST

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Makoto, E-mail: hasegawa@triam.kyushu-u.ac.jp; Nakamura, Kazuo; Zushi, Hideki; Hanada, Kazuaki; Fujisawa, Akihide; Tokunaga, Kazutoshi; Idei, Hiroshi; Nagashima, Yoshihiko; Kawasaki, Shoji; Nakashima, Hisatoshi; Higashijima, Aki

    2016-11-15

    Highlights: • Overall configuration of plasma control system on QUEST are presented. • Multi core system and reflective memories are used for the real-time control. • Hall sensors are used for the identification of plasma current and its position. • Repetitive gas fueling with the feed-back control of Hα signal is implemented. - Abstract: The plasma control system (PCS) of QUEST is developed according to the progress of QUEST project. Since one of the critical goals of the project is to achieve the steady-state operation with high temperature vacuum vessel wall, the PCS is also required to have the capability to control the plasma for a long period. For the increase of the loads to processing power of the PCS, the PCS is decentralized with the use of reflective memories (RFMs). The PCS controls the plasma edge position with the real-time identification of plasma current and its position. This identification is done with not only flux loops but also hall sensors. The gas fueling method by piezo valve with monitoring the Hα signal filtered by a digital low-pass filter are proposed and suitable for the steady-state operation on QUEST. The present status and prospect of the PCS are presented with recent topics.

  18. Selection of Steady-State Process Simulation Software to Optimize Treatment of Radioactive and Hazardous Waste

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Todd Travis; Barnes, Charles Marshall; Lauerhass, Lance; Taylor, Dean Dalton

    2001-06-01

    The process used for selecting a steady-state process simulator under conditions of high uncertainty and limited time is described. Multiple waste forms, treatment ambiguity, and the uniqueness of both the waste chemistries and alternative treatment technologies result in a large set of potential technical requirements that no commercial simulator can totally satisfy. The aim of the selection process was two-fold. First, determine the steady-state simulation software that best, albeit not completely, satisfies the requirements envelope. And second, determine if the best is good enough to justify the cost. Twelve simulators were investigated with varying degrees of scrutiny. The candidate list was narrowed to three final contenders: ASPEN Plus 10.2, PRO/II 5.11, and CHEMCAD 5.1.0. It was concluded from "road tests" that ASPEN Plus appears to satisfy the project's technical requirements the best and is worth acquiring. The final software decisions provide flexibility: they involve annual rather than multi-year licensing, and they include periodic re-assessment.

  19. Selection of Steady-State Process Simulation Software to Optimize Treatment of Radioactive and Hazardous Waste

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, T. T.; Barnes, C. M.; Lauerhass, L.; Taylor, D. D.

    2001-06-01

    The process used for selecting a steady-state process simulator under conditions of high uncertainty and limited time is described. Multiple waste forms, treatment ambiguity, and the uniqueness of both the waste chemistries and alternative treatment technologies result in a large set of potential technical requirements that no commercial simulator can totally satisfy. The aim of the selection process was two-fold. First, determine the steady-state simulation software that best, albeit not completely, satisfies the requirements envelope. And second, determine if the best is good enough to justify the cost. Twelve simulators were investigated with varying degrees of scrutiny. The candidate list was narrowed to three final contenders: ASPEN Plus 10.2, PRO/II 5.11, and CHEMCAD 5.1.0. It was concluded from ''road tests'' that ASPEN Plus appears to satisfy the project's technical requirements the best and is worth acquiring. The final software decisions provide flexibility: they involve annual rather than multi-year licensing, and they include periodic re-assessment.

  20. Steady-state pharmacokinetics of metformin is independent of the OCT1 genotype in healthy volunteers

    DEFF Research Database (Denmark)

    Christensen, Mette Marie Hougaard; Højlund, Kurt; Hother-Nielsen, Ole

    2015-01-01

    PURPOSE: The aim of the study was to determine the steady-state pharmacokinetics of metformin in healthy volunteers with different numbers of reduced-function alleles in the organic cation transporter 1 gene (OCT1). METHODS: The study was conducted as part of a randomized cross-over trial. Thirty......-four healthy volunteers with known OCT1 genotypes (12 with two wild-type alleles, 13 with one and 9 with two reduced-function alleles) were included. In one of the study periods, they were titrated to steady-state with 1 g metformin twice daily. RESULTS: Neither AUC(0-12), C(max) nor Cl(renal) were...... statistically significantly affected by the number of reduced-function alleles (0, 1 or 2) in OCT1: (AUC(0-12): 0, 1, 2: 14, 13 and 14 h ng/L (P = 0.61)); (C(max): 0, 1, 2: 2192, 1934 and 2233 ng/mL, (P = 0.26)) and (Cl(renal): 0, 1, 2: 31, 28 and 30 L/h (P = 0.57)) CONCLUSIONS: In a cohort of healthy...

  1. A high-density EEG investigation into steady state binaural beat stimulation.

    Directory of Open Access Journals (Sweden)

    Peter Goodin

    Full Text Available Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz or Beta (16 Hz frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others.

  2. Testing steady states carbon stocks of Yasso07 and ROMUL models against soil inventory data in Finland

    Science.gov (United States)

    Lehtonen, Aleksi; Linkosalo, Tapio; Heikkinen, Juha; Peltoniemi, Mikko; Sievänen, Risto; Mäkipää, Raisa; Tamminen, Pekka; Salemaa, Maija; Komarov, Alexander

    2015-04-01

    Soil carbon pool is a significant storage of carbon. Unfortunately, the significance of different drivers of this pool is still unknown. In order to predict future feedbacks of soils to climate change at global level, Earth system model (ESMs) are needed. These ESMs have been tested against soil carbon inventories in order to judge whether models can be used for future prediction. Unfortunately results have been poor, and e.g. Guenet et al. 2013 presents a test where soil carbon stocks by ORCHIDEE models are plotted at plot level against measurements without any correlation. Similarly, Todd-Brown et al. (2013) concludes that most ESMs are not able reproduce measured soil carbon stocks at grid level. Here we estimated litter input from trees and understorey vegetation to soil, based national forest inventory 9 data. Both, biomass estimates for trees and for understorey vegetation were smoothed with ordinary kriging methods and thereafter litter input was modeled by dominant tree species. Also regional litter input from natural mortality and harvesting residues were added to the input. Thereafter we applied Yasso07 (Tuomi et al. 2011) and ROMUL (Chertov et al. 2001) soil models to estimate steady-state carbon stocks for mineral soils of Finland on a 10*10 km2 grid. We run Yasso07 model with annual time step and using parameters based on Scandinavian data (Rantakari et al. 2012) and also with parameters based on global data set (Tuomi et al. 2011). ROMUL model was applied with and without soil water holding capacity information. Results were compared against Biosoil measurements of soil carbon stocks (n=521). We found out that the best match between model estimates and measurements by latitudinal bands (n=43) were by ROMUL model with soil water holding capacity, with RMSE of 9.9 Mg C. Second best match was with Yasso07 with Scandinavian parameters, with RMSE of 15.3 Mg C. Results of this study highlight two things, it is essential to run dynamic soil models with time

  3. Problems of providing of steady development of public transport and public transport charges

    OpenAIRE

    Elagin, Y.

    2011-01-01

    In the article essence of conception of steady development, going near determination of external public charges of transport and principle of creation of mechanisms of motivation of steady development of public transport, is considered on makroand microlevels.

  4. The non-steady-state oceanic CO2 signal: its importance, magnitude and a novel way to detect it

    Science.gov (United States)

    McNeil, B. I.; Matear, R. J.

    2012-09-01

    The ocean's role has been pivotal in modulating rising atmospheric CO2 levels since the industrial revolution, sequestering over a quarter of all fossil-fuel derived CO2 emissions. Net oceanic uptake of CO2 has roughly doubled between the 1960's (~1 Pg C yr-1) and 2000's (~2 Pg C yr-1), with expectations it will continue to absorb even more CO2 with rising future atmospheric CO2 levels. However, recent CO2 observational analyses along with numerous model predictions suggest the rate of oceanic CO2 uptake is already slowing, largely as a result of a natural decadal-scale outgassing signal. This recent and unexpected CO2 outgassing signal represents a paradigm-shift in our understanding of the oceans role in modulating atmospheric CO2. Current tracer-based estimates for the ocean storage of anthropogenic CO2 assume the ocean circulation and biology is in steady state, thereby missing the new and potentially important "non-steady-state" CO2 outgassing signal. By combining data-based techniques that assume the ocean is in steady-state, with techniques that constrain the net oceanic CO2 uptake signal, we show how to extract the non-steady-state CO2 signal from observations. Over the entire industrial era, the non-steady-state CO2 outgassing signal (~13 ± 10 Pg C) is estimated to represent about 9% of the total net CO2 inventory change (~142 Pg C). However between 1989 and 2007, the non-steady-state CO2 outgassing signal (~6.3 Pg C) has likely increased to be ~18% of net oceanic CO2 storage over that period (~36 Pg C), a level which cannot be ignored. The present uncertainty of our data-based techniques for oceanic CO2 uptake limit our capacity to quantify the non-steady-state CO2 signal, however with more data and better certainty estimates across a~range of diverse methods, this important and growing CO2 signal could be better constrained in the future.

  5. The non-steady state oceanic CO2 signal: its importance, magnitude and a novel way to detect it

    Science.gov (United States)

    McNeil, B. I.; Matear, R. J.

    2013-04-01

    The role of the ocean has been pivotal in modulating rising atmospheric CO2 levels since the industrial revolution, sequestering nearly half of all fossil-fuel derived CO2 emissions. Net oceanic uptake of CO2 has roughly doubled between the 1960s (~1 Pg C yr-1) and 2000s (~2 Pg C yr-1), with expectations that it will continue to absorb even more CO2 with rising future atmospheric CO2 levels. However, recent CO2 observational analyses along with numerous model predictions suggest the rate of oceanic CO2 uptake is already slowing, largely as a result of a natural decadal-scale outgassing signal. This recent CO2 outgassing signal represents a significant shift in our understanding of the oceans role in modulating atmospheric CO2. Current tracer-based estimates for the ocean storage of anthropogenic CO2 assume the ocean circulation and biology is in steady state, thereby missing the new and potentially important "non-steady state" CO2 outgassing signal. By combining data-based techniques that assume the ocean is in a steady state, with techniques that constrain the net oceanic CO2 uptake signal, we show how to extract the non-steady state CO2 signal from observations. Over the entire industrial era, the non-steady state CO2 outgassing signal (~13 ± 10 Pg C) is estimated to represent about 9% of the total net CO2 inventory change (~142 Pg C). However, between 1989 and 2007, the non-steady state CO2 outgassing signal (~6.3 Pg C) has likely increased to be ~18% of net oceanic CO2 storage over that period (~36 Pg C). The present uncertainty of our data-based techniques for oceanic CO2 uptake limit our capacity to quantify the non-steady state CO2 signal, however with more data and better certainty estimates across a range of diverse methods, this important and growing CO2 signal could be better constrained in the future.

  6. The non-steady state oceanic CO2 signal: its importance, magnitude and a novel way to detect it

    Directory of Open Access Journals (Sweden)

    B. I. McNeil

    2013-04-01

    Full Text Available The role of the ocean has been pivotal in modulating rising atmospheric CO2 levels since the industrial revolution, sequestering nearly half of all fossil-fuel derived CO2 emissions. Net oceanic uptake of CO2 has roughly doubled between the 1960s (~1 Pg C yr−1 and 2000s (~2 Pg C yr−1, with expectations that it will continue to absorb even more CO2 with rising future atmospheric CO2 levels. However, recent CO2 observational analyses along with numerous model predictions suggest the rate of oceanic CO2 uptake is already slowing, largely as a result of a natural decadal-scale outgassing signal. This recent CO2 outgassing signal represents a significant shift in our understanding of the oceans role in modulating atmospheric CO2. Current tracer-based estimates for the ocean storage of anthropogenic CO2 assume the ocean circulation and biology is in steady state, thereby missing the new and potentially important "non-steady state" CO2 outgassing signal. By combining data-based techniques that assume the ocean is in a steady state, with techniques that constrain the net oceanic CO2 uptake signal, we show how to extract the non-steady state CO2 signal from observations. Over the entire industrial era, the non-steady state CO2 outgassing signal (~13 ± 10 Pg C is estimated to represent about 9% of the total net CO2 inventory change (~142 Pg C. However, between 1989 and 2007, the non-steady state CO2 outgassing signal (~6.3 Pg C has likely increased to be ~18% of net oceanic CO2 storage over that period (~36 Pg C. The present uncertainty of our data-based techniques for oceanic CO2 uptake limit our capacity to quantify the non-steady state CO2 signal, however with more data and better certainty estimates across a range of diverse methods, this important and growing CO2 signal could be better constrained in the future.

  7. The requirements of a next step large steady state tokamak

    Science.gov (United States)

    Janeschitz, G.; Barabaschi, P.; Federici, G.; Ioki, K.; Ladd, P.; Mukhovatov, V.; Sugihara, M.; Tivey, R.; ITER-JCT; Home Team

    2000-06-01

    After a decision by the ITER parties to investigate the possibility of designing a reduced cost version of ITER several possible machine layouts with different aspect ratios were studied. Relatively early in this process it became clear that there is no significant cost difference between different aspect ratios and that there is a maximum realistically possible aspect ratio for a machine with 6 m major radius and rather high plasma shaping. Following this study a machine with an intermediate aspect ratio (3.1) called the ITER Fusion Energy Advanced Tokamak (ITER FEAT) was chosen as the basis for the outline design of a reduced cost ITER. Several potential steady state scenarios can be investigated in ITER FEAT, i.e. monotonic or reversed shear at full or reduced minor radius. In addition, so-called hybrid discharges, are feasible where a mixture of inductive and non-inductive current drive as well as bootstrap current allows long pulse discharges of the order of 2500 s. The βN values and H factors required for these discharges are in the same range as those observed on present machines, which provides confidence that such discharges can be studied in ITER FEAT. However, due to uncertainties in physics knowledge, for example the current drive efficiency off-axis, it is impossible at present to generate a completely self-consistent scenario taking all boundary conditions, for example engineering or heating system constraints, into account. In addition, all of these regimes have a potential problem with divertor operation compatibility (low edge density) and with helium exhaust which has to be addressed in existing experiments. For the engineering design of the in-vessel components and for the balance of the plant there is practically no difference between inductive (500 s) and steady state operation. However, the choice of heating systems and the distribution of power between them will be strongly influenced by the envisaged steady state scenarios.

  8. Relaxation versus adiabatic quantum steady-state preparation

    Science.gov (United States)

    Venuti, Lorenzo Campos; Albash, Tameem; Marvian, Milad; Lidar, Daniel; Zanardi, Paolo

    2017-04-01

    Adiabatic preparation of the ground states of many-body Hamiltonians in the closed-system limit is at the heart of adiabatic quantum computation, but in reality systems are always open. This motivates a natural comparison between, on the one hand, adiabatic preparation of steady states of Lindbladian generators and, on the other hand, relaxation towards the same steady states subject to the final Lindbladian of the adiabatic process. In this work we thus adopt the perspective that the goal is the most efficient possible preparation of such steady states, rather than ground states. Using known rigorous bounds for the open-system adiabatic theorem and for mixing times, we are then led to a disturbing conclusion that at first appears to doom efforts to build physical quantum annealers: relaxation seems to always converge faster than adiabatic preparation. However, by carefully estimating the adiabatic preparation time for Lindbladians describing thermalization in the low-temperature limit, we show that there is, after all, room for an adiabatic speedup over relaxation. To test the analytically derived bounds for the adiabatic preparation time and the relaxation time, we numerically study three models: a dissipative quasifree fermionic chain, a single qubit coupled to a thermal bath, and the "spike" problem of n qubits coupled to a thermal bath. Via these models we find that the answer to the "which wins" question depends for each model on the temperature and the system-bath coupling strength. In the case of the "spike" problem we find that relaxation during the adiabatic evolution plays an important role in ensuring a speedup over the final-time relaxation procedure. Thus, relaxation-assisted adiabatic preparation can be more efficient than both pure adiabatic evolution and pure relaxation.

  9. The structure of steady shock waves in porous metals

    Science.gov (United States)

    Czarnota, Christophe; Molinari, Alain; Mercier, Sébastien

    2017-10-01

    The paper aims at developing an understanding of steady shock wave propagation in a ductile metallic material containing voids. Porosity is assumed to be less than 0.3 and voids are not connected (foams are not considered). As the shock wave is traveling in the porous medium, the voids are facing a rapid collapse. During this dynamic compaction process, material particles are subjected to very high acceleration in the vicinity of voids, thus generating acceleration forces at the microscale that influence the overall response of the porous material. Analyzing how stationary shocks are influenced by these micro-inertia effects is the main goal of this work. The focus is essentially on the shock structure, ignoring oscillatory motion of pores prevailing at the tail of the shock wave. Following the constitutive framework developed by Molinari and Ravichandran (2004) for the analysis of steady shock waves in dense metals, an analytical approach of steady state propagation of plastic shocks in porous metals is proposed. The initial void size appears as a characteristic internal length that scales the overall dynamic response, thereby contributing to the structuring of the shock front. This key feature is not captured by standard damage models where the porosity stands for the single damage parameter with no contribution of the void size. The results obtained in this work provide a new insight in the fundamental understanding of shock waves in porous media. In particular, a new scaling law relating the shock width to the initial void radius is obtained when micro-inertia effects are significant.

  10. On the minimum circulating power of steady state tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, K.; Itoh, S.; Fukuyama, A.; Yagi, M.

    1995-07-01

    Circulating power for the sustenance and profile control of the steady state tokamak plasmas is discussed. The simultaneous fulfillment of the MHD stability at high beta value, the improved confinement and the stationary equilibrium requires the rotation drive as well as the current drive. In addition to the current drive efficiency, the efficiency for the rotation drive is investigated. The direct rotation drive by the external torque, such as the case of beam injection, is not efficient enough. The mechanism and the magnitude of the spontaneous plasma rotation are studied. (author).

  11. Steady State Analysis of Stochastic Systems with Multiple Time Delays

    Science.gov (United States)

    Xu, W.; Sun, C. Y.; Zhang, H. Q.

    In this paper, attention is focused on the steady state analysis of a class of nonlinear dynamic systems with multi-delayed feedbacks driven by multiplicative correlated Gaussian white noises. The Fokker-Planck equations for delayed variables are at first derived by Novikov's theorem. Then, under small delay assumption, the approximate stationary solutions are obtained by the probability density approach. As a special case, the effects of multidelay feedbacks and the correlated additive and multiplicative Gaussian white noises on the response of a bistable system are considered. It is shown that the obtained analytical results are in good agreement with experimental results in Monte Carlo simulations.

  12. Steady-state grain growth in UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Galinari, C.M.; Lameiras, F.S. [CDTN/CNEN, Belo Horizonte (Brazil)

    1998-06-05

    The authors have observed steady-state grain growth in sintered UO{sub 2} pellets of nuclear purity at 2,003 K under H{sub 2}. The behavior of the grain size distribution at different instants is consistent with the grain growth model proposed by one of the authors. The total number of grains was estimated using the Saltykov`s method, and the evolution is in accordance with the model proposed by Rhines and Craig. The parabolic growth law was observed for the mean intercept length with n = 0.4.

  13. Cluster sizes in interleaved silent steady state (ISSS) imaging.

    Science.gov (United States)

    Akrofi, Kwaku; Sutton, Bradley P; Ouyang, Cheng; Husain, Fatima T

    2011-01-01

    The effect of increasing the number of scans in the "cluster" of an interleaved silent steady state (ISSS) fMRI imaging scheme from 1 to 2, and then to 3 was examined by a fixed-effects analysis of an auditory short-term memory task with four subjects. Compared to a cluster size of 1, a cluster of 2 scans improved sensitivity at detecting brain activity and statistical power, while a cluster of 3 scans further improved statistical power but seemed not to improve sensitivity beyond that achieved with a cluster of 2 scans. The findings reveal that cluster size is a vital parameter for an ISSS imaging scheme.

  14. Quantum reciprocity conjecture for the non-equilibrium steady state

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, P; Mao, W [Center for Materials Theory, Rutgers University, Piscataway, NJ 08854 (United States)

    2004-05-26

    A consideration of the lack of history dependence in the non-equilibrium steady state of a quantum system leads us to conjecture that in such a system there is a set of quantum mechanical observables whose retarded response functions are insensitive to the arrow of time, and which consequently satisfy a quantum analogue of the Onsager reciprocity relations. Systems which satisfy this conjecture can be described by an effective free energy functional. We demonstrate that the conjecture holds in a resonant level model of a multi-lead quantum dot. (letter to the editor)

  15. Morphological instability during steady electrodeposition at overlimiting currents

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2015-01-01

    We present a linear stability analysis of a planar metal electrode during steady electrodeposition. We extend the previous work of Sundstrom and Bark by accounting for the extended space-charge density, which develops at the cathode once the applied voltage exceeds a few thermal voltages....... In accordance with Chazalviel's conjecture, the extended space-charge region is found to greatly affect the morphological stability of the electrode. To supplement the numerical solution of the stability problem, we have derived analytical expressions valid in the limit of low and high voltage, respectively....

  16. Non-Equilibrium Steady States of the XY Chain

    CERN Document Server

    Aschbacher, W H

    2002-01-01

    We study the non-equilibrium statistical mechanics of the two-sided XY chain. We start from an initial state in which the left and right part of the lattice {x|xM}, are at inverse temperatures beta_L and beta_R. Using a simple scattering theoretic analysis, we construct the unique non-equilibrium steady state (NESS). This state depends on beta_L and beta_R, but not on the choice of the decoupling parameter M. We prove that in the non-equilibrium case, beta_L \

  17. An Improved SIMPLEC Method for Steady and Unsteady Flow Computations

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Michelsen, Jess; Sørensen, N. N.

    2003-01-01

    A modified SIMPLEC scheme for flow computations on collocated grids has been developed. It is demonstrated that the standard SIMPLEC scheme (1) is inconsistent when applied on collocated grids. Hence, for steady computations the computed solution depends on the velocity underrelaxation parameter fu......, whereas the solutions of unsteady computations for small time steps are polluted by unphysical wiggles. A revised scheme is proposed that extends the capability of th SIMPLEC method to cope with collocated grids in a general and consistent way.The efficiency of the new scheme is demonstrated by computing...... flows past a circular cylinder and an airfoil....

  18. Nanosecond Time Resolved and Steady State Infrared Studies of Photoinduced Decomposition of TATB at Ambient and Elevated Pressures

    Science.gov (United States)

    Glascoe, Elizabeth A.; Zaug, Joseph M.; Armstrong, Michael R.; Crowhurst, Jonathan C.; Grant, Christian D.; Fried, Laurence E.

    2009-06-01

    The timescale and/or products of photo-induced decomposition of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were investigated at ambient and elevated pressures. Ultrafast time-resolved infrared and steady state Fourier transform IR (FTIR) spectroscopies were used to probe TATB and its products after photoexcitation with a 5 nanosecond pulse of 532 nm light. At ambient pressure, transient spectra of TATB indicate that the molecule has significantly decomposed within 60 nanoseconds; transient spectra also indicate that formation of CO2, an observed decomposition product, is complete within 30-40 microseconds. Comparison of steady-state FTIR spectra obtained at ambient and elevated pressure (ca. 8 GPa) indicate that the decomposition products vary with pressure and only the high pressure decomposition produces water.

  19. Liaisons dangereuses: HIV risk behavior and prevention in steady gay relationships

    NARCIS (Netherlands)

    Davidovich, E.

    2006-01-01

    This dissertation studied sexual risk-taking behavior among gay men in steady relationships. The main targets of this study were to establish: (a) whether steady relationships form a risk environment for HIV-infection; (b) some of the determinants of risky and protective behavior between steady

  20. Global Instability and Transient Growth in a Model Fusifom Aneurysm with Steady Inflow

    Science.gov (United States)

    Sheard, Gregory; Blackburn, Hugh

    2010-11-01

    The stability of the flow through a model aneurysm is computed using a global linear stability analysis and a direct transient growth analysis. The geometry consists of sinusoidal expansion in a circular pipe. Dimensions are chosen to represent a human abdominal aortic aneurysm near to the critical bulge size requiring surgical intervention. The bulge length and maximum width are 2.9 and 1.9 times the pipe diameter, respectively. Subject to a steady inflow, the flow is found to be weakly unstable to quasi-periodic global eigenmodes with azimuthal wavenumbers of 4 and 5 at a Reynolds number (based on area-averaged velocity and pipe diameter) of Re 3900. Perturbation structures in these eigenmodes are concentrated in the outer part of the bulge towards its downstream end. A transient growth analysis reveals that the flow is sensitive to transient disturbances beyond Re=33, well below the time-averaged Reynolds numbers of blood flow in the human abdominal aorta.

  1. Vesicle dynamics in a confined Poiseuille flow: From steady state to chaos

    Science.gov (United States)

    Aouane, Othmane; Thiébaud, Marine; Benyoussef, Abdelilah; Wagner, Christian; Misbah, Chaouqi

    2014-09-01

    Red blood cells (RBCs) are the major component of blood, and the flow of blood is dictated by that of RBCs. We employ vesicles, which consist of closed bilayer membranes enclosing a fluid, as a model system to study the behavior of RBCs under a confined Poiseuille flow. We extensively explore two main parameters: (i) the degree of confinement of vesicles within the channel and (ii) the flow strength. Rich and complex dynamics for vesicles are revealed, ranging from steady-state shapes (in the form of parachute and slipper shapes) to chaotic dynamics of shape. Chaos occurs through a cascade of multiple periodic oscillations of the vesicle shape. We summarize our results in a phase diagram in the parameter plane (degree of confinement and flow strength). This finding highlights the level of complexity of a flowing vesicle in the small Reynolds number where the flow is laminar in the absence of vesicles and can be rendered turbulent due to elasticity of vesicles.

  2. Observations of steady anomalous magnetic heating in thin current sheets. [of solar corona

    Science.gov (United States)

    Martens, P. C. H.; Van Den Oord, G. H. J.; Hoyng, P.

    1985-01-01

    The Hard X-ray Imaging Spectrometer of the Solar Maximum Mission has yielded observations of a faint, steadily emitting loop-like structure, which have allowed the thermal evolution of this loop over a period of about 15 hr to be followed. Only 0.1 percent of the volume of the loop appears to be steadily heated, at the large rate of 0.6 erg/cu cm sec; this suggests that the heating represents the dissipation of magnetic fields in thin current sheets. Ion-kinetic tearing, as proposed by Galeev et al. (1981), is noted to be especially consonant with these observations. The source of the present X-ray emission is identified with the H-alpha filament in the same region. The present findings are held to constitute the first direct evidence for the steady dissipation of coronal magnetic fields via enhanced thin current sheet resistivity.

  3. Bubbles and fingers in a Hele-Shaw cell: steady solutions

    CERN Document Server

    Vasconcelos, Giovani L

    2015-01-01

    Analytical solutions for both a finite assembly and a periodic array of bubbles steadily moving in a Hele-Shaw channel are presented. The particular case of multiple fingers penetrating into the channel and moving jointly with an assembly of bubbles is also analysed. The solutions are given by a conformal mapping from a multiply connected circular domain in an auxiliary complex plane to the fluid region exterior to the bubbles. In all cases the desired mapping is written explicitly in terms of certain special transcendental functions, known as the secondary Schottky-Klein prime functions. Taken together, the solutions reported here represent the complete set of solutions for steady bubbles (and fingers) in a horizontal Hele-Shaw channel when surface tension is neglected. All previous solutions under these assumptions are particular cases of the general solutions reported here. Other possible applications of the formalism described here are also discussed.

  4. Phononic heat transport in nanomechanical structures: steady-state and pumping

    Science.gov (United States)

    Sena-Junior, Marcone I.; Lima, Leandro R. F.; Lewenkopf, Caio H.

    2017-10-01

    We study the heat transport due to phonons in nanomechanical structures using a phase space representation of non-equilibrium Green’s functions. This representation accounts for the atomic degrees of freedom making it particularly suited for the description of small (molecular) junctions systems. We rigorously show that for the steady state limit our formalism correctly recovers the heuristic Landauer-like heat conductance for a quantum coherent molecular system coupled to thermal reservoirs. We find general expressions for the non-stationary heat current due to an external periodic drive. In both cases we discuss the quantum thermodynamic properties of the systems. We apply our formalism to the case of a diatomic molecular junction.

  5. Effect of hydraulic hysteresis on the stability of infinite slopes under steady infiltration

    Science.gov (United States)

    Chen, Pan; Mirus, Benjamin B.; Lu, Ning; Godt, Jonathan W.

    2017-01-01

    Hydraulic hysteresis, including capillary soil water retention (SWR), air entrapment SWR, and hydraulic conductivity, is a common phenomenon in unsaturated soils. However, the influence of hydraulic hysteresis on suction stress, and subsequently slope stability, is generally ignored. This paper examines the influence of each of these three types of hysteresis on slope stability using an infinite slope stability analysis under steady infiltration conditions. First, hypothetical slopes for representative silty and sandy soils are examined. Then a monitored hillslope in the San Francisco Bay Area, California is assessed, using observed rainfall conditions and measured hydraulic and geotechnical properties of the colluvial soil. Results show that profiles of suction stress and the corresponding factor of safety are generally strongly affected by hydraulic hysteresis. Results suggest that each of the three types of hydraulic hysteresis may play a major role in the occurrence of slope failure, indicating that ignoring hydraulic hysteresis will likely lead to underestimates of failure potential and hence to inaccurate slope stability analysis.

  6. Unconfined laminar nanofluid flow and heat transfer around a rotating circular cylinder in the steady regime

    Directory of Open Access Journals (Sweden)

    Bouakkaz Rafik

    2017-06-01

    Full Text Available In this work, steady flow-field and heat transfer through a copper- water nanofluid around a rotating circular cylinder with a constant nondimensional rotation rate α varying from 0 to 5 was investigated for Reynolds numbers of 5–40. Furthermore, the range of nanoparticle volume fractions considered is 0–5%. The effect of volume fraction of nanoparticles on the fluid flow and heat transfer characteristics are carried out by using a finite-volume method based commercial computational fluid dynamics solver. The variation of the local and the average Nusselt numbers with Reynolds number, volume fractions, and rotation rate are presented for the range of conditions. The average Nusselt number is found to decrease with increasing value of the rotation rate for the fixed value of the Reynolds number and volume fraction of nanoparticles. In addition, rotation can be used as a drag reduction technique.

  7. Steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system

    Science.gov (United States)

    Brooks, Lynette E.; Masbruch, Melissa D.; Sweetkind, Donald S.; Buto, Susan G.

    2014-01-01

    This report describes the construction, calibration, evaluation, and results of a steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system that was developed as part of the U.S. Geological Survey National Water Census Initiative to evaluate the nation’s groundwater availability. The study area spans 110,000 square miles across five states. The numerical model uses MODFLOW-2005, and incorporates and tests complex hydrogeologic and hydrologic elements of a conceptual understanding of an interconnected groundwater system throughout the region, including mountains, basins, consolidated rocks, and basin fill. The level of discretization in this model has not been previously available throughout the study area.

  8. Origin and Evolution of Short-Period Comets

    Science.gov (United States)

    Nesvorny, David; Vokrouhlicky, David; (Luke) Dones, Henry C.; Levison, Harold F.; Kaib, Nathan A.; Morbidelli, Alessandro

    2017-10-01

    Comets are icy objects that orbitally evolve from the trans-Neptunian region (the Kuiper belt and beyond) into the inner Solar System, where they are heated by solar radiation and become active due to sublimation of water ice. Here we perform end-to-end simulations in which cometary reservoirs are formed in the early Solar System and evolved over 4.5 Gyr. The gravitational effects of Planet 9 (P9), hypothesized to circle the Sun on a wide orbit, are included in some of our simulations. Different models are considered for comets to be active, including a simple assumption that comets remain active for Np(q) perihelion passages with perihelion distance q1000 is required to obtain a steady-state population of large active HTCs that is consistent with observations. To fit the ratio of the returning-to-new OCCs, by contrast, our model implies that Np(2.5)<10, possibly because the detected long-period comets are smaller and much easier to disrupt than observed HTCs.

  9. Integrated stoichiometric, thermodynamic and kinetic modelling of steady state metabolism

    Science.gov (United States)

    Fleming, R.M.T.; Thiele, I.; Provan, G.; Nasheuer, H.P.

    2010-01-01

    The quantitative analysis of biochemical reactions and metabolites is at frontier of biological sciences. The recent availability of high-throughput technology data sets in biology has paved the way for new modelling approaches at various levels of complexity including the metabolome of a cell or an organism. Understanding the metabolism of a single cell and multi-cell organism will provide the knowledge for the rational design of growth conditions to produce commercially valuable reagents in biotechnology. Here, we demonstrate how equations representing steady state mass conservation, energy conservation, the second law of thermodynamics, and reversible enzyme kinetics can be formulated as a single system of linear equalities and inequalities, in addition to linear equalities on exponential variables. Even though the feasible set is non-convex, the reformulation is exact and amenable to large-scale numerical analysis, a prerequisite for computationally feasible genome scale modelling. Integrating flux, concentration and kinetic variables in a unified constraint-based formulation is aimed at increasing the quantitative predictive capacity of flux balance analysis. Incorporation of experimental and theoretical bounds on thermodynamic and kinetic variables ensures that the predicted steady state fluxes are both thermodynamically and biochemically feasible. The resulting in silico predictions are tested against fluxomic data for central metabolism in E. coli and compare favourably with in silico prediction by flux balance analysis. PMID:20230840

  10. Thermodynamic Analysis of Closed Steady or Cyclic Systems

    Directory of Open Access Journals (Sweden)

    Jim McGovern

    2015-09-01

    Full Text Available Closed, steady or cyclic thermodynamic systems, which have temperature variations over their boundaries, can represent an extremely large range of plants, devices or natural objects, such as combined heating, cooling and power plants, computers and data centres, and planets. Energy transfer rates can occur across the boundary, which are characterized as heat or work. We focus on the finite time thermodynamics aspects, on energy-based performance parameters, on rational efficiency and on the environmental reference temperature. To do this, we examine the net work rate of a closed, steady or cyclic system bounded by thermal resistances linked to isothermal reservoirs in terms of the first and second laws of thermodynamics. Citing relevant references from the literature, we propose a methodology that can improve the thermodynamic analysis of an energy-transforming or an exergy-destroying plant. Through the reflections and analysis presented, we have found an explanation of the second law that clarifies the link between the Clausius integral of heat over temperature and the reference temperature of the Gouy–Stodola theorem. With this insight and approach, the specification of the environmental reference temperature in exergy analysis becomes more solid. We have explained the relationship between the Curzon Ahlborn heat engine and an irreversible Carnot heat engine. We have outlined the nature of subsystem rational efficiencies and have found Rant’s anergy to play an important role. We postulate that heat transfer through thermal resistance is the sole basis of irreversibility.

  11. Modeling steady-state methanogenic degradation of phenols in groundwater

    Science.gov (United States)

    Bekins, Barbara A.; Godsy, E. Michael; Goerlitz, Donald F.

    1993-01-01

    Field and microcosm observations of methanogenic phenolic compound degradation indicate that Monod kinetics governs the substrate disappearance but overestimates the observed biomass. In this paper we present modeling results from an ongoing multidisciplinary study of methanogenic biodegradation of phenolic compounds in a sand and gravel aquifer contaminated by chemicals and wastes used in wood treatment. Field disappearance rates of four phenols match those determined in batch microcosm studies previously performed by E.M. Godsy and coworkers. The degradation process appears to be at steady-state because even after a sustained influx over several decades, the contaminants still are disappearing in transport downgradient. The existence of a steady-state degradation profile of each substrate together with a low biomass density in the aquifer indicate that the bacteria population is exhibiting no net growth. This may be due to the oligotrophic nature of the biomass population in which utilization and growth are approximately independent of concentration for most of the concentration range. Thus a constant growth rate should exist over much of the contaminated area which may in turn be balanced by an unusually high decay or maintenance rate due to hostile conditions or predation.

  12. Classical Orbital Paramagnetism in Non-equilibrium Steady State

    Science.gov (United States)

    Deshpande, Avinash A.; Kumar, N.

    2017-09-01

    We report the results of our numerical simulation of classical-dissipative dynamics of a charged particle subjected to a non-Markovian stochastic forcing. We find that the system develops a steady-state orbital magnetic moment in the presence of a static magnetic field. Very significantly, the sign of the orbital magnetic moment turns out to be paramagnetic for our choice of parameters, varied over a wide range. This is shown specifically for the case of classical dynamics driven by a Kubo-Anderson type non-Markovian noise. Natural spatial boundary condition was imposed through (1) a soft (harmonic) confining potential, and (2) a hard potential, approximating a reflecting wall. There was no noticeable qualitative difference. What appears to be crucial to the orbital magnetic effect noticed here is the non-Markovian property of the driving noise chosen. Experimental realization of this effect on the laboratory scale, and its possible implications are briefly discussed. We would like to emphasize that the above steady-state classical orbital paramagnetic moment complements, rather than contradicts the Bohr-van Leeuwen (BvL) theorem on the absence of classical orbital diamagnetism in thermodynamic equilibrium.

  13. Transient and steady-state selection in the striatal microcircuit

    Directory of Open Access Journals (Sweden)

    Adam eTomkins

    2014-01-01

    Full Text Available Although the basal ganglia have been widely studied and implicated in signal processing and action selection, little information is known about the active role the striatal microcircuit plays in action selection in the basal ganglia-thalamo-cortical loops. To address this knowledge gap we use a large scale three dimensional spiking model of the striatum, combined with a rate coded model of the basal ganglia-thalamo-cortical loop, to asses the computational role the striatum plays in action selection. We identify a robust transient phenomena generated by the striatal microcircuit, which temporarily enhances the difference between two competing cortical inputs. We show that this transient is sufficient to modulate decision making in the basal ganglia-thalamo-cortical circuit. We also find that the transient selection originates from a novel adaptation effect in single striatal projection neurons, which is amenable to experimental testing. Finally, we compared transient selection with models implementing classical steady-state selection. We challenged both forms of model to account for recent reports of paradoxically enhanced response selection in Huntington's Disease patients. We found that steady-state selection was uniformly impaired under all simulated Huntington's conditions, but transient selection was enhanced given a sufficient Huntington's-like increase in NMDA receptor sensitivity. Thus our models provide an intriguing hypothesis for the mechanisms underlying the paradoxical cognitive improvements in manifest Huntington's patients.

  14. Steady states of the parametric rotator and pendulum

    Energy Technology Data Exchange (ETDEWEB)

    Bouzas, Antonio O, E-mail: abouzas@fis.mda.cinvestav.m [Departamento de Fisica Aplicada, CINVESTAV-IPN, Carretera Antigua a Progreso Km. 6, Apdo Postal 73 ' Cordemex' , Merida 97310, Yucatan (Mexico)

    2010-11-15

    We discuss several steady-state rotation and oscillation modes of the planar parametric rotator and pendulum with damping. We consider a general elliptic trajectory of the suspension point for both rotator and pendulum, for the latter at an arbitrary angle with gravity, with linear and circular trajectories as particular cases. We treat the damped, nonlinear equation of motion of the parametric rotator and pendulum perturbatively for small parametric excitation and damping, although our perturbative approach can be extended to other regimes as well. Our treatment involves only ordinary second-order differential equations with constant coefficients, and provides numerically accurate perturbative solutions in terms of elementary functions. Some of the steady-state rotation and oscillation modes studied here have not been discussed in the previous literature. Other well-known ones, such as parametric resonance and the inverted pendulum, are extended to elliptic parametric excitation tilted with respect to gravity. The results presented here should be accessible to advanced undergraduates, and of interest to graduate students and specialists in the field of nonlinear mechanics.

  15. Characterization of steady streaming for a particle manipulation system.

    Science.gov (United States)

    Amit, Roni; Abadi, Avi; Kosa, Gabor

    2016-04-01

    Accurate positioning of biological cells or microscopic particle without directly contacting them is a challenging task in biomedical engineering. Various trapping methods for controlling the position of a particle have been suggested. The common driving methods are based on laser and ultrasonic actuation principles. In this work we suggest a design for a hydrodynamic particle manoeuvring system. The system operates using steady streaming in a viscous fluid media induced by high frequency vibration of piezoelectric cantilevers. A particle within the workspace of the system can be trapped and manipulated to a desired position by the fairly unidirectional flow field created by the beams. In this paper, the flow field in the particle manipulation system is characterized numerically and experimentally. We find that the flow field resembles the analytical solutions of a flow field created by an oscillating sphere. Furthermore, we validate numerically the quadratic relation between the steady streaming velocity and the vibration amplitude of the beam. The calibration of the piezoelectric actuator's oscillation amplitudes enables effective positioning of particles with a diameter of 20 um to 1 mm. We find that a 30X0.8X2 mm(3) piezoelectric beam vibrating at its first resonance frequency, 200 Hz, is able to move a particle at a typical flow velocity ranging between 0.05 mm/sec and 0.13 mm/s in 430 cSt Si oil (Re=0.2).

  16. State of the Magnetotail: Steady and Bursty Magnetospheric Convection

    Science.gov (United States)

    Tanskanen, E. I.; Slavin, J. A.

    2004-12-01

    Geotail and Cluster observations are used to examine the state of the Earth's magnetotail. In this paper we are particularly interested about the plasma sheet convection and the tail "stress level". Tail static pressure (magnetic + thermal pressure) is used to characterize different convection modes, and earthward bulk velocity is used to identify burstyness of the plasma sheet. Four basic convection modes are identified: loading, unloading, steady magnetospheric convection (SMC) and continuous magnetospheric dissipation (CMD). Bulk ion velocity is used to characterize the nature of the convection in the plasma sheet during each of these states. Bursty bulk flows (BBFs) were found to be basic building blocks of the all the tail states. When solar wind drives magnetosphere over several substorm cycle (> 8 hours) the plasma sheet was observed to be highly active and non-steady. The tail stress level was studied by using magnetic and plasma measurements from four Cluster spacecraft. Tail total current was computed, and x-component of the J cross B was used as a "tail stress index". Examples of slightly and strongly stretched magnetotail will be presented and the validity of the tail stress index will be evaluated.

  17. Steady-state flow properties of amorphous materials

    Science.gov (United States)

    Jadhao, Vikram; O'Connor, Thomas; Robbins, Mark

    2015-03-01

    Molecular dynamics (MD) simulations are used to investigate the steady-state shear flow curves of a standard glass model: the bidisperse Lennard-Jones system. For a wide range of temperatures in the neighborhood of the glass transition temperature Tg predicted by the mode coupling theory, we compute the steady-state shear stress and viscosity as a function of the shear rate γ ˙. At temperatures near and above Tg, the stress crosses over from linear Newtonian behavior at low rates to power law shear-thinning at high rates. As T decreases below Tg, the stress shows a plateau, becoming nearly rate-independent at low γ ˙. There is a weak increase in stress that is consistent with Eyring theory for activated flow of a solid. We find that when the strain rate is reduced to extremely low values, Newtonian behavior appears once more. Insights gained from these simulations are applied to the computation of flow curves of a well-established boundary lubricant: squalane. In the elastohydrodynamic regime, squalane responds like a glassy solid with an Eyring-like response, but at low rates it has a relatively small Newtonian viscosity. Supported by the Army Research Laboratory under Grant W911NF-12-2-0022.

  18. Nd-Sr isotopic compositions of dissolved and particulate material transported by the Parana and Uruguay rivers during high (december 1993) and low (september 1994) water periods; Compositions isotopiques de Nd et Sr des matieres en suspension et dissoutes transportees par les fleuves Parana et Uraguay en periodes de hautes (decembre 1993) et basses (septembre 1994) eaux

    Energy Technology Data Exchange (ETDEWEB)

    Henry, F.; Thouron, D.; Garcon, V. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Henry, F. [Universite du Litoral, 62 - Wimereux (France). Laboratoire de Chimie Analytique appliquee a l' Environnement Naturel; Probst, J.L. [Universidad Nacional, Cordoba (Argentina). Facultad de Ciencias Exactas, Fisicas y Naturales

    1996-07-01

    Our motivation is to better constrain the neodymium and strontium isotopic signatures of the closest continental riverine source (Parana and Uruguay rivers) to the Brazil/Malvinas Confluence zone in the Southwest Atlantic Ocean. We thus present new isotopic data on the Nd and Sr of the dissolved and suspended loads of the Parana and Uruguay rivers for two water periods forming the Rio de la Plata whose drainage basin is the second largest one in South America. The Parana dissolved material shows less radiogenic ({epsilon}{sub Nd} (0) ranging between -12.1 and -8.2) than the Uruguay one with a mean {epsilon}{sub Nd} (0) value of -6.3 {+-} 0.3. Suspended particulates display the same isotopic trend (mean {epsilon}{sub Nd} (0) value of -10.3 and -6.0 for the Parana and Uruguay rivers, respectively). Dissolved load {sup 87}Sr/{sup 86}Sr in the Parana (0.7123) is found to be more radiogenic than the Uruguay one (0.7097); the suspended load follows the same trend with {sup 87}Sr/{sup 86}Sr ratios of 0.7247 and 0.7115 in the Parana and Uruguay rivers, respectively. The relatively radiogenic Nd and non radiogenic Sr of the Uruguay River as compared to the Parana River could be attributed to a predominance of tholeiitic basalts in the drainage basin. A revisited estimation of the fluxes of Nd considering all South American rivers delivering into the western South and Tropical Atlantic Ocean yields a Nd particulate flux to estuarine water two orders of magnitude higher than the Nd dissolved flux. Considering the net dissolved and suspended fluxes of Nd reaching the Rio de la Plata, we have calculated a resulting {epsilon}{sub Nd} (0) equal to -10.2. The computation of {epsilon}{sub Nd} (0) of the Rio de la Plata outflow waters gives a value of -8.3, taking into account various removal processes within the estuary. (authors)

  19. Pu recycling in a full Th-MOX PWR core. Part I: Steady state analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fridman, E., E-mail: e.fridman@fzd.d [Institute of Safety Research, Forschungszentrum Dresden-Rossendorf, POB 51 01 19, Dresden 01314 (Germany); Kliem, S. [Institute of Safety Research, Forschungszentrum Dresden-Rossendorf, POB 51 01 19, Dresden 01314 (Germany)

    2011-01-15

    Research highlights: Detailed 3D 100% Th-MOX PWR core design is developed. Pu incineration increased by a factor of 2 as compared to a full MOX PWR core. The core controllability under steady state conditions is demonstrated. - Abstract: Current practice of Pu recycling in existing Light Water Reactors (LWRs) in the form of U-Pu mixed oxide fuel (MOX) is not efficient due to continuous Pu production from U-238. The use of Th-Pu mixed oxide (TOX) fuel will considerably improve Pu consumption rates because virtually no new Pu is generated from thorium. In this study, the feasibility of Pu recycling in a typical pressurized water reactor (PWR) fully loaded with TOX fuel is investigated. Detailed 3-dimensional 100% TOX and 100% MOX PWR core designs are developed. The full MOX core is considered for comparison purposes. The design stages included determination of Pu loading required to achieve 18-month fuel cycle assuming three-batch fuel management scheme, selection of poison materials, development of the core loading pattern, optimization of burnable poison loadings, evaluation of critical boron concentration requirements, estimation of reactivity coefficients, core kinetic parameters, and shutdown margin. The performance of the MOX and TOX cores under steady-state condition and during selected reactivity initiated accidents (RIAs) is compared with that of the actual uranium oxide (UOX) PWR core. Part I of this paper describes the full TOX and MOX PWR core designs and reports the results of steady state analysis. The TOX core requires a slightly higher initial Pu loading than the MOX core to achieve the target fuel cycle length. However, the TOX core exhibits superior Pu incineration capabilities. The significantly degraded worth of control materials in Pu cores is partially addressed by the use of enriched soluble boron and B{sub 4}C as a control rod absorbing material. Wet annular burnable absorber (WABA) rods are used to flatten radial power distribution. The

  20. Periodic and quasi-periodic solutions for multi-instabilities involved in brake squeal

    Science.gov (United States)

    Coudeyras, N.; Nacivet, S.; Sinou, J.-J.

    2009-12-01

    This paper is devoted to the computation of nonlinear dynamic steady-state solutions of autonomous systems subjected to multi-instabilities and proposes a new nonlinear method for predicting periodic and quasi-periodic solutions intended for application to the disc brake squeal phenomenon. Firstly, finite element models of a pad and a disc are reduced to include only their contact nodes by using a Craig and Bampton strategy. Secondly, a complex eigenvalue analysis is performed showing two unstable modes for a wide range of friction coefficients, after which a Generalized Constrained Harmonic Balance Method (GCHBM) is presented. This method can compute nonlinear periodic or pseudo-periodic responses depending on the number of unstable frequencies. The numerical results are in good agreement with those of time marching methods.

  1. Metabolic effects of intermittent hypoxia in mice: steady versus high-frequency applied hypoxia daily during the rest period.

    Science.gov (United States)

    Carreras, Alba; Kayali, Foaz; Zhang, Jing; Hirotsu, Camila; Wang, Yang; Gozal, David

    2012-10-01

    Intermittent hypoxia (IH) is a frequent occurrence in sleep and respiratory disorders. Both human and murine studies show that IH may be implicated in metabolic dysfunction. Although the effects of nocturnal low-frequency intermittent hypoxia (IH(L)) have not been extensively examined, it would appear that IH(L) and high-frequency intermittent hypoxia (IH(H)) may elicit distinct metabolic adaptations. To this effect, C57BL/6J mice were randomly assigned to IH(H) (cycles of 90 s 6.4% O(2) and 90 s 21% O(2) during daylight), IH(L) (8% O(2) during daylight hours), or control (CTL) for 5 wk. At the end of exposures, some of the mice were subjected to a glucose tolerance test (GTT; after intraperitoneal injection of 2 mg glucose/g body wt), and others were subjected to an insulin tolerance test (ITT; 0.25 units Humulin/kg body wt), with plasma leptin and insulin levels being measured in fasting conditions. Skeletal muscles were harvested for GLUT4 and proliferator-activated receptor gamma coactivator 1-α (PGC1-α) expression. Both IH(H) and IH(L) displayed reduced body weight increases compared with CTL. CTL mice had higher basal glycemic levels, but GTT kinetics revealed marked differences between IH(L) and IH(H), with IH(L) manifesting the lowest insulin sensitivity compared with either IH(H) or CTL, and such findings were further confirmed by ITT. No differences emerged in PGC1-α expression across the three experimental groups. However, while cytosolic GLUT4 protein expression remained similar in IH(L), IH(H), and CTL, significant decreases in GLUT4 membrane fraction occurred in hypoxia and were most pronounced in IH(L)-exposed mice. Thus IH(H) and IH(L) elicit differential glucose homeostatic responses despite similar cumulative hypoxic profiles.

  2. One-Dimensional Vacuum Steady Seepage Model of Unsaturated Soil and Finite Difference Solution

    Directory of Open Access Journals (Sweden)

    Feng Huang

    2017-01-01

    Full Text Available Vacuum tube dewatering method and light well point method have been widely used in engineering dewatering and foundation treatment. However, there is little research on the calculation method of unsaturated seepage under the effect of vacuum pressure which is generated by the vacuum well. In view of this, the one-dimensional (1D steady seepage law of unsaturated soil in vacuum field has been analyzed based on Darcy’s law, basic equations, and finite difference method. First, the gravity drainage ability is analyzed. The analysis presents that much unsaturated water can not be drained off only by gravity effect because of surface tension. Second, the unsaturated vacuum seepage equations are built up in conditions of flux boundary and waterhead boundary. Finally, two examples are analyzed based on the relationship of matric suction and permeability coefficient after boundary conditions are determined. The results show that vacuum pressure will significantly enhance the drainage ability of unsaturated water by improving the hydraulic gradient of unsaturated water.

  3. Stationary Distribution and Thermodynamic Relation in Nonequilibrium Steady States

    KAUST Repository

    Komatsu, Teruhisa S.

    2010-01-01

    We describe our recent attempts toward statistical mechanics and thermodynamics for nonequilibrium steady states (NESS) realized, e.g., in a heat conducting system. Our first result is a simple expression of the probability distribution (of microscopic states) of a NESS. Our second result is a natural extension of the thermodynamic Clausius relation and a definition of an accompanying entropy in NESS. This entropy coincides with the normalization constant appearing in the above mentioned microscopic expression of NESS, and has an expression similar to the Shannon entropy (with a further symmetrization). The NESS entropy proposed here is a clearly defined measurable quantity even in a system with a large degrees of freedom. We numerically measure the NESS entropy in hardsphere fluid systems with a heat current, by observing energy exchange between the system and the heat baths when the temperatures of the baths are changed according to specified protocols.

  4. Millisecond pulsars with r-modes as steady gravitational radiators.

    Science.gov (United States)

    Reisenegger, Andreas; Bonacić, Axel

    2003-11-14

    Millisecond pulsars (MSPs) probably achieve their fast rotation by mass transfer from their companion stars in low-mass x-ray binaries (LMXBs). The lack of MSPs and LMXBs rotating near breakup has been attributed to the accretion torque being balanced, at fast rotation, by gravitational radiation, perhaps caused by an unstable oscillation mode. It has been argued that internal dissipation involving hyperons may cause LMXBs to evolve into a quasisteady state, with nearly constant rotation rate, temperature, and mode amplitude. We show that MSPs descending from these LMXBs spend a long time in a similar state, as extremely steady sources of gravitational waves and thermal x rays, while they spin down due to gravitational radiation and the standard magnetic torque. Observed MSP braking torques already place meaningful constraints on this scenario.

  5. Analysis of steady-state ductile crack growth

    DEFF Research Database (Denmark)

    Niordson, Christian

    1999-01-01

    The fracture strength under quasi-static steady-state crack growth in an elastic-plastic material joined by a laser weld is analyzed. Laser welding gives high mismatch between the yield stress within the weld and the yield stress in the base material. This is due to the fast termic cycle, which....... Both models predict that in general a thinner laser weld gives higher interface strength. Furthermore, both fracture criteria show, that the preferred path of the crack is close outside the weld material; a phenomenon also observed in experiments....... the material undergoes in welding. The elastic properties, on the other hand, are insensitive to the termic cycle, and are therefore essentially the same in the weld and in the base material. The material is described by $J_2$-flow theory, and the analysis is performed by using a numerical algorithm, in which...

  6. An Adsorption Equilibria Model for Steady State Analysis

    KAUST Repository

    Ismail, Azhar Bin

    2016-02-29

    The investigation of adsorption isotherms is a prime factor in the ongoing development of adsorption cycles for a spectrum of advanced, thermally-driven engineering applications, including refrigeration, natural gas storage, and desalination processes. In this work, a novel semi-empirical mathematical model has been derived that significantly enhances the prediction of the steady state uptake in adsorbent surfaces. This model, a combination of classical Langmuir and a novel modern adsorption isotherm equation, allows for a higher degree of regression of both energetically homogenous and heterogeneous adsorbent surfaces compared to several isolated classical and modern isotherm models, and has the ability to regress isotherms for all six types under the IUPAC classification. Using a unified thermodynamic framework, a single asymmetrical energy distribution function (EDF) has also been proposed that directly relates the mathematical model to the adsorption isotherm types. This fits well with the statistical rate theory approach and offers mechanistic insights into adsorption isotherms.

  7. Optimal operation of Petlyuk distillation: Steady-state behavior

    Directory of Open Access Journals (Sweden)

    Ivar J. Halvorsen

    2001-07-01

    Full Text Available The "Petlyuk" or "dividing-wall" or "fully thermally coupled" distillation column is an interesting alternative to the conventional cascaded binary columns for separation of multi-component mixtures. However, the industrial use has been limited, and difficulties in operation have been reported as one reason. With three product compositions controlled, the system has two degrees of freedom left for on-line optimization. We show that the steady-state optimal solution surface is quite narrow, and depends strongly on disturbances and design parameters. Thus it seems difficult to achieve the potential energy savings compared to conventional approaches without a good control strategy. We discuss candidate variables which may be used as feedback variables in order to keep the column operation close to optimal in a "self-optimizing" control scheme.

  8. Steady-State Chemotactic Response in E. coli

    CERN Document Server

    Kafri, Yariv

    2007-01-01

    The bacterium E. coli maneuvers itself to regions with high chemoattractant concentrations by performing two stereotypical moves: `runs', in which it moves in near straight lines, and `tumbles', in which it does not advance but changes direction randomly. The duration of each move is stochastic and depends upon the chemoattractant concentration experienced in the recent past. We relate this stochastic behavior to the steady-state density of a bacterium population, and we derive the latter as a function of chemoattractant concentration. In contrast to earlier treatments, here we account for the effects of temporal correlations and variable tumbling durations. A range of behaviors obtains, that depends subtly upon several aspects of the system - memory, correlation, and tumbling stochasticity in particular.

  9. Creep stresses in a spherical shell under steady state temperature

    Science.gov (United States)

    Verma, Gaurav; Rana, Puneet

    2017-10-01

    The paper investigates the problem of creep of a spherical structure under the influence of steady state temperature. The problem of creep in spherical shell is solved by using the concept of generalized strain measures and transition hypothesis given by Seth. The problem has reduced to non-linear differential equation for creep transition. This paper deals with the non-linear behaviour of spherical shell under thermal condition. The spherical shell structures are easily vulnerable to creep, shrinkage and thermal effects; a thorough understanding of their time-dependent behaviour has been fully established. The paper aims to provide thermal creep analysis to enhance the effective design and long life of shells, and a theoretical model is developed for calculating creep stresses and strains in a spherical shell with purpose. Results obtained for the problem are depicted graphically.

  10. Postural control and shoulder steadiness in F-16 pilots

    DEFF Research Database (Denmark)

    Lange, Britt; Murray, Mike; Chreiteh, Shadi S

    2014-01-01

    reports the results of the secondary objective, which was to increase the understanding of possible mechanisms underlying such neck pain and its intervention-related relief. METHODS: In a parallel, single-blinded, randomized controlled study, 55 F-16 pilots were evaluated at baseline and randomized......BACKGROUND: During maneuvering, fighter pilots experience loads of up to 50-70 kg on their necks. Neck disorders are common and have been linked to impairment in muscle control. We conducted an intervention study introducing targeted training for 24 wk that reduced neck pain. The current study...... to a control group (CG; N = 28) or training group (TG; N = 27). Postural control was tested in four different settings: Romberg with open and closed eyes, unilateral stance, and perturbation. Maximal voluntary contraction and force steadiness was measured for shoulder elevation. RESULTS: At follow...

  11. Fast Prediction Method for Steady-State Heat Convection

    KAUST Repository

    Wáng, Yì

    2012-03-14

    A reduced model by proper orthogonal decomposition (POD) and Galerkin projection methods for steady-state heat convection is established on a nonuniform grid. It was verified by thousands of examples that the results are in good agreement with the results obtained from the finite volume method. This model can also predict the cases where model parameters far exceed the sample scope. Moreover, the calculation time needed by the model is much shorter than that needed for the finite volume method. Thus, the nonuniform POD-Galerkin projection method exhibits high accuracy, good suitability, and fast computation. It has universal significance for accurate and fast prediction. Also, the methodology can be applied to more complex modeling in chemical engineering and technology, such as reaction and turbulence. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. NASA Lewis Steady-State Heat Pipe Code Architecture

    Science.gov (United States)

    Mi, Ye; Tower, Leonard K.

    2013-01-01

    NASA Glenn Research Center (GRC) has developed the LERCHP code. The PC-based LERCHP code can be used to predict the steady-state performance of heat pipes, including the determination of operating temperature and operating limits which might be encountered under specified conditions. The code contains a vapor flow algorithm which incorporates vapor compressibility and axially varying heat input. For the liquid flow in the wick, Darcy s formula is employed. Thermal boundary conditions and geometric structures can be defined through an interactive input interface. A variety of fluid and material options as well as user defined options can be chosen for the working fluid, wick, and pipe materials. This report documents the current effort at GRC to update the LERCHP code for operating in a Microsoft Windows (Microsoft Corporation) environment. A detailed analysis of the model is presented. The programming architecture for the numerical calculations is explained and flowcharts of the key subroutines are given

  13. Liquid-liquid separation using steady-state bed coalescer

    Directory of Open Access Journals (Sweden)

    Šećerov-Sokolović Radmila M.

    2016-01-01

    Full Text Available This paper presents a literature review on the current understanding of liquid-liquid separation that is immensely widespread in practice, highlighting the steady-state bed coalescer being a good solution in various engineering application. Generally, the fibre bed coalescence has proven to be very effective separation method in the industry. Due to the complexity of bed coalescence phenomenon coalescer design and sizing procedure relies on experimental test. This review provides a research overview of the key phenomena essential for the efficient bed coalescence, such as mechanisms of droplet coalescence and emulsion flow through the fibre bed. In addition to this provides an overview of the current knowledge about coalescer´s design properties and variables such as: fluid velocity, fluid flow orientation/flow mode, fibre bed geometry, and bed length. [[Projekat Ministarstva nauke Republike Srbije, br. 172022

  14. Outsourcing and "dismantling" of steady jobs at hospitals

    Directory of Open Access Journals (Sweden)

    Helton Saragor de Souza

    2016-04-01

    Full Text Available Abstract OBJECTIVE To relate hospitals' organizational structure as the core of a web of outsourced services and flexible employment bonds among healthcare professionals in the context of finance capitalism, analyzing work arrangements based mainly on the type of employment bond. METHOD Qualitative research through ethnography, interviews, data analysis, and case studies. The case studies were concentrated in 3 hospitals located in the São Paulo metropolitan region under different management types: public administration; outsourced administration via a healthcare social organization (HSO; and private administration. RESULTS This study highlights a trend in outsourcing, dismantling of steady jobs, and shaping working relations asymmetrically in terms of healthcare professions. CONCLUSION These aspects are characteristic of contemporary capitalism and post-Fordist work organization. In this context, the state under sponsorship cripples the very existence of an effective human resources policy, creating a favorable environment for outsourcing and flexibility of employment bonds among healthcare workers.

  15. Manifest and Subtle Cyclic Behavior in Nonequilibrium Steady States

    CERN Document Server

    Zia, R K P; Mandal, Dibyendu; Fox-Kemper, Baylor

    2016-01-01

    Many interesting phenomena in nature are described by stochastic processes with irreversible dynamics. To model these phenomena, we focus on a master equation or a Fokker-Planck equation with rates which violate detailed balance. When the system settles in a stationary state, it will be a nonequilibrium steady state (NESS), with time independent probability distribution as well as persistent probability current loops. The observable consequences of the latter are explored. In particular, cyclic behavior of some form must be present: some are prominent and manifest, while others are more obscure and subtle. We present a theoretical framework to analyze such properties, introducing the notion of "probability angular momentum" and its distribution. Using several examples, we illustrate the manifest and subtle categories and how best to distinguish between them. These techniques can be applied to reveal the NESS nature of a wide range of systems in a large variety of areas. We illustrate with one application: var...

  16. Positive contrast MR imaging of tendons, ligaments, and menisci by subtraction of signals from a double echo steady state sequence (Sub-DESS).

    Science.gov (United States)

    Martirosian, Petros; Schraml, Christina; Springer, Fabian; Schwenzer, Nina F; Würslin, Christian; Schick, Fritz; Deimling, Michael

    2014-01-01

    To improve the visualization of fibrous tissues as tendons, ligaments and fibrocartilage structures as menisci by positive contrast using a new 3D Double Echo Steady State (DESS) sequence. The proposed 3D DESS sequence works with separate acquisition of a first echo with an echo time (TE1 ) of 1.2 ms followed by a more heavily T2 -weighted second echo recorded at time TE2 . Subtraction of images from both echoes leads to positive signal from fibrous tissues, whereas in other tissues as musculature and fat the subtraction signal nearly vanishes due to almost similar signal strength in both echoes. Systematic measurements in healthy volunteers with different sets of pulse repetition time (TR), TE1 , readout bandwidth and flip angle were performed to determine optimal sequence parameters. The presented 3D sequence with Cartesian readout requires relatively short measuring time, provides reasonable signal-to-noise ratio and can be easily implemented in protocols for clinical musculoskeletal MR imaging. Degenerative changes or tears of tendons, ligaments and fibrocartilage are known to cause increased water content and therefore prolongation of transverse relaxation times, which leads to reduced signal intensities in the "subtraction images." Positive contrast of fibrous tissue as demonstrated by the proposed sub-DESS approach provides improved conspicuity and allows for three-dimensional reconstruction especially of structures with curved geometry. Copyright © 2013 Wiley Periodicals, Inc.

  17. Magnetic reconnection during steady magnetospheric convection and other magnetospheric modes

    Science.gov (United States)

    Hubert, Benoit; Gérard, Jean-Claude; Milan, Steve E.; Cowley, Stanley W. H.

    2017-03-01

    We use remote sensing of the proton aurora with the IMAGE-FUV SI12 (Imager for Magnetopause to Aurora Global Exploration-Far Ultraviolet-Spectrographic Imaging at 121.8 nm) instrument and radar measurements of the ionospheric convection from the SuperDARN (Super Dual Aurora Radar Network) facility to estimate the open magnetic flux in the Earth's magnetosphere and the reconnection rates at the dayside magnetopause and in the magnetotail during intervals of steady magnetospheric convection (SMC). We find that SMC intervals occur with relatively high open magnetic flux (average ˜ 0.745 GWb, standard deviation ˜ 0.16 GWb), which is often found to be nearly steady, when the magnetic flux opening and closure rates approximately balance around 55 kV on average, with a standard deviation of 21 kV. We find that the residence timescale of open magnetic flux, defined as the ratio between the open magnetospheric flux and the flux closure rate, is roughly 4 h during SMCs. Interestingly, this number is approximately what can be deduced from the discussion of the length of the tail published by Dungey (1965), assuming a solar wind speed of ˜ 450 km s-1. We also infer an enhanced convection velocity in the tail, driving open magnetic flux to the nightside reconnection site. We compare our results with previously published studies in order to identify different magnetospheric modes. These are ordered by increasing open magnetic flux and reconnection rate as quiet conditions, SMCs, substorms (with an important overlap between these last two) and sawtooth intervals.

  18. Non-steady wind turbine response to daytime atmospheric turbulence.

    Science.gov (United States)

    Nandi, Tarak N; Herrig, Andreas; Brasseur, James G

    2017-04-13

    Relevant to drivetrain bearing fatigue failures, we analyse non-steady wind turbine responses from interactions between energy-dominant daytime atmospheric turbulence eddies and the rotating blades of a GE 1.5 MW wind turbine using a unique dataset from a GE field experiment and computer simulation. Time-resolved local velocity data were collected at the leading and trailing edges of an instrumented blade together with generator power, revolutions per minute, pitch and yaw. Wind velocity and temperature were measured upwind on a meteorological tower. The stability state and other atmospheric conditions during the field experiment were replicated with a large-eddy simulation in which was embedded a GE 1.5 MW wind turbine rotor modelled with an advanced actuator line method. Both datasets identify three important response time scales: advective passage of energy-dominant eddies (≈25-50 s), blade rotation (once per revolution (1P), ≈3 s) and sub-1P scale (<1 s) response to internal eddy structure. Large-amplitude short-time ramp-like and oscillatory load fluctuations result in response to temporal changes in velocity vector inclination in the aerofoil plane, modulated by eddy passage at longer time scales. Generator power responds strongly to large-eddy wind modulations. We show that internal dynamics of the blade boundary layer near the trailing edge is temporally modulated by the non-steady external flow that was measured at the leading edge, as well as blade-generated turbulence motions.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

  19. Generating multiple contrasts using single-shot radial T1 sensitive and insensitive steady-state imaging.

    Science.gov (United States)

    Benkert, Thomas; Bartsch, Andreas J; Blaimer, Martin; Jakob, Peter M; Breuer, Felix A

    2015-06-01

    Recently, the (Resolution Enhanced-) T1 insensitive steady-state imaging (TOSSI) approach has been proposed for the fast acquisition of T2 -weighted images. This has been achieved by balanced steady-state free precession (bSSFP) imaging between unequally spaced inversion pulses. The purpose of this work is to present an extension of this technique, considerably increasing both the efficiency and possibilities of TOSSI. A radial trajectory in combination with an appropriate view-sharing reconstruction is used. Because each projection traverses the contrast defining k-space center, several different contrasts can be extracted from a single-shot measurement. These contrasts include various T2 -weightings and T2 /T1 -weighting if an even number of inversion pulses is used, while an odd number allow the generation of several images with predefined tissue types cancelled. The approach is validated for brain and abdominal imaging at 3.0 Tesla. Results are compared with RE-TOSSI, bSSFP, and turbo spin-echo images and are shown to provide similar contrasts in a fraction of scan time. Furthermore, the potential utility of the approach is illustrated by images obtained from a brain tumor patient. Radial T1 sensitive and insensitive steady-state imaging is able to generate multiple contrasts out of one single-shot measurement in a short scan time. © 2014 Wiley Periodicals, Inc.

  20. Visual quasi-periodicity

    NARCIS (Netherlands)

    Pogalin, E.; Smeulders, A.W.M.; Thean, A.H.C.

    2008-01-01

    Periodicity is at the core of the recognition of many actions. This paper takes the following steps to detect and measure periodicity. 1) We establish a conceptual framework of classifying periodicity in 10 essential cases, the most important of which are flashing (of a traffic light), pulsing (of

  1. Fat attenuation using a dual steady‐state balanced‐SSFP sequence with periodically variable flip angles

    National Research Council Canada - National Science Library

    Absil, J; Denolin, V; Metens, T

    2006-01-01

    .... The sequence uses periodically variable flip angles and produces a dual steady state of the signal, which is obtained after a dual transient phase if an appropriate preparation is used. The off...

  2. Observations of water movement in a block of fractured welded Tuff

    Energy Technology Data Exchange (ETDEWEB)

    Thamir, F.; Kwicklis, E.M. [Geological Survey, Denver, CO (United States); Hampson, D. [Foothills Engineering Consultants Inc., Golden, CO (United States); Anderton, S. [ROCKTECH West Jordan, UT (United States)

    1994-12-31

    A laboratory water infiltration experiment through a block of fractured, moderately welded volcanic tuff was conducted at different boundary pressures. The block measured 47.5 cm long {times} 54.3 cm wide {times} 80.6 cm high. The purpose of the experiment was: (a) to test an instrumentation scheme for a field test, and (b) to make flow measurements through a fractured network at different boundary pressures to understand mechanisms that affect fracture flow. The upper boundary water pressure was decreased in steps; each step lasted several weeks where the pressure was kept steady. Water inflow and outflow rates were measured for each boundary condition. Entrapped air was found to impede water movement. The gas phase in the fracture network was found to not be continuous; its pressure within the network was not known. The matric potential values could not be measured with tensiometers alone since a known gas pressure is required. Long-term input and output flow rates were equal. Outflow rate did not stabilize during the test period; it continued to decrease, even when the upper boundary water pressure was kept steady. No relation between boundary pressure and flow rate was established. Bacteria, which was found in the outflow, possibly caused variations in the behavior. Trapped air caused the outflow to periodically decrease or stop; however, outflow rates following the interruptions did not change long-term flow trends.

  3. Moxidectin steady state prior to inoculation protects cats from subsequent, repeated infection with Dirofilaria immitis.

    Science.gov (United States)

    Little, Susan E; Hostetler, Joe A; Thomas, Jennifer E; Bailey, Keith L; Barrett, Anne W; Gruntmeir, Kaylynn; Gruntmeir, Jeff; Starkey, Lindsay A; Basel, Chris; Blagburn, Byron L

    2015-02-18

    Infection of cats with Dirofilaria immitis causes seroconversion on antibody tests and pulmonary pathology, often without subsequent development of adult heartworms. Consistent administration of topical 10% imidacloprid-1% moxidectin has been shown to result in sustained plasma levels of moxidectin in cats after three to five treatments, a pharmacokinetic behavior known as "steady state". To evaluate the ability of moxidectin at "steady state" to protect cats from subsequent infection with D. immitis, cats (n = 10) were treated with the labeled dose of topical 10% imidacloprid-1% moxidectin for four monthly treatments. Each cat was inoculated with 25 third-stage larvae of D. immitis 7, 14, 21, and 28 days after the last treatment; non-treated cats (n = 9) were inoculated on the same days, serving as infection controls. Blood samples were collected from each cat from 1 month prior to treatment until 7 months after the final inoculation and tested for antibody to, and antigen and microfilaria of, D. immitis. Measurement of serum levels of moxidectin confirmed steady state in treated cats. Cats treated with topical 10% imidacloprid-1% moxidectin prior to trickle inoculation of D. immitis L3 larvae throughout the 28 day post-treatment period remained negative on antibody and antigen tests throughout the study and did not develop gross or histologic lesions characteristic of heartworm infection. A majority of non-treated cats tested antibody positive by 3-4 months post infection (6/9) and, after heat treatment, tested antigen positive by 6-7 months post-infection (5/9). Histologic lesions characteristic of D. immitis infection, including intimal and medial thickening of the pulmonary artery, were present in every cat with D. immitis antibodies (6/6), although adult D. immitis were confirmed in only 5/6 antibody-positive cats at necropsy. Microfilariae were not detected at any time. Taken together, these data indicate that prior treatment with 10% imidacloprid-1

  4. Experimental calibration and validation of sewer/surface flow exchange equations in steady and unsteady flow conditions

    Science.gov (United States)

    Rubinato, Matteo; Martins, Ricardo; Kesserwani, Georges; Leandro, Jorge; Djordjević, Slobodan; Shucksmith, James

    2017-09-01

    The linkage between sewer pipe flow and floodplain flow is recognised to induce an important source of uncertainty within two-dimensional (2D) urban flood models. This uncertainty is often attributed to the use of empirical hydraulic formulae (the one-dimensional (1D) weir and orifice steady flow equations) to achieve data-connectivity at the linking interface, which require the determination of discharge coefficients. Because of the paucity of high resolution localised data for this type of flows, the current understanding and quantification of a suitable range for those discharge coefficients is somewhat lacking. To fulfil this gap, this work presents the results acquired from an instrumented physical model designed to study the interaction between a pipe network flow and a floodplain flow. The full range of sewer-to-surface and surface-to-sewer flow conditions at the exchange zone are experimentally analysed in both steady and unsteady flow regimes. Steady state measured discharges are first analysed considering the relationship between the energy heads from the sewer flow and the floodplain flow; these results show that existing weir and orifice formulae are valid for describing the flow exchange for the present physical model, and yield new calibrated discharge coefficients for each of the flow conditions. The measured exchange discharges are also integrated (as a source term) within a 2D numerical flood model (a finite volume solver to the 2D Shallow Water Equations (SWE)), which is shown to reproduce the observed coefficients. This calibrated numerical model is then used to simulate a series of unsteady flow tests reproduced within the experimental facility. Results show that the numerical model overestimated the values of mean surcharge flow rate. This suggests the occurrence of additional head losses in unsteady conditions which are not currently accounted for within flood models calibrated in steady flow conditions.

  5. Effects of pumping strategies on pesticide concentration of a drinking water well

    DEFF Research Database (Denmark)

    Aisopou, Angeliki; Binning, Philip John; Bjerg, Poul Løgstrup

    was to examine numerically the effects of pumping on pesticide contamination of drinking water wells using a reactive transport model in a hypothetical aquifer system resembling a typical Danish well field. The application history of the pesticides is crucial. This can be taken into account by assessing...... was assumed for the application period of each pesticide. The pre-abstraction age distribution of the water in the system was first estimated using a steady-state flow and transport simulation. These water ages were then used as the initial conditions for the transient simulations. The results......Groundwater is an important source of drinking water production in many countries including Denmark. This requires high quality groundwater that meets the standards of the European Water Framework Directive. Yet as a result of agricultural activitity, deposition and previous handling, pesticides...

  6. A Quasi-Steady Lifting Line Theory for Insect-Like Hovering Flight.

    Directory of Open Access Journals (Sweden)

    Mostafa R A Nabawy

    Full Text Available A novel lifting line formulation is presented for the quasi-steady aerodynamic evaluation of insect-like wings in hovering flight. The approach allows accurate estimation of aerodynamic forces from geometry and kinematic information alone and provides for the first time quantitative information on the relative contribution of induced and profile drag associated with lift production for insect-like wings in hover. The main adaptation to the existing lifting line theory is the use of an equivalent angle of attack, which enables capture of the steady non-linear aerodynamics at high angles of attack. A simple methodology to include non-ideal induced effects due to wake periodicity and effective actuator disc area within the lifting line theory is included in the model. Low Reynolds number effects as well as the edge velocity correction required to account for different wing planform shapes are incorporated through appropriate modification of the wing section lift curve slope. The model has been successfully validated against measurements from revolving wing experiments and high order computational fluid dynamics simulations. Model predicted mean lift to weight ratio results have an average error of 4% compared to values from computational fluid dynamics for eight different insect cases. Application of an unmodified linear lifting line approach leads on average to a 60% overestimation in the mean lift force required for weight support, with most of the discrepancy due to use of linear aerodynamics. It is shown that on average for the eight insects considered, the induced drag contributes 22% of the total drag based on the mean cycle values and 29% of the total drag based on the mid half-stroke values.

  7. Nonconstant Positive Steady States and Pattern Formation of 1D Prey-Taxis Systems

    Science.gov (United States)

    Wang, Qi; Song, Yang; Shao, Lingjie

    2017-02-01

    Prey-taxis is the process that predators move preferentially toward patches with highest density of prey. It is well known to have an important role in biological control and the maintenance of biodiversity. To model the coexistence and spatial distributions of predator and prey species, this paper concerns nonconstant positive steady states of a wide class of prey-taxis systems with general functional responses over 1D domain. Linearized stability of the positive equilibrium is analyzed to show that prey-taxis destabilizes prey-predator homogeneity when prey repulsion (e.g., due to volume-filling effect in predator species or group defense in prey species) is present, and prey-taxis stabilizes the homogeneity otherwise. Then, we investigate the existence and stability of nonconstant positive steady states to the system through rigorous bifurcation analysis. Moreover, we provide detailed and thorough calculations to determine properties such as pitchfork and turning direction of the local branches. Our stability results also provide a stable wave mode selection mechanism for thee reaction-advection-diffusion systems including prey-taxis models considered in this paper. Finally, we provide numerical studies of prey-taxis systems with Holling-Tanner kinetics to illustrate and support our theoretical findings. Our numerical simulations demonstrate that the 2× 2 prey-taxis system is able to model the formation and evolution of various striking patterns, such as spikes, periodic oscillations, and coarsening even when the domain is one-dimensional. These dynamics can model the coexistence and spatial distributions of interacting prey and predator species. We also give some insights on how system parameters influence pattern formation in these models.

  8. A Quasi-Steady Lifting Line Theory for Insect-Like Hovering Flight.

    Science.gov (United States)

    Nabawy, Mostafa R A; Crowthe, William J

    2015-01-01

    A novel lifting line formulation is presented for the quasi-steady aerodynamic evaluation of insect-like wings in hovering flight. The approach allows accurate estimation of aerodynamic forces from geometry and kinematic information alone and provides for the first time quantitative information on the relative contribution of induced and profile drag associated with lift production for insect-like wings in hover. The main adaptation to the existing lifting line theory is the use of an equivalent angle of attack, which enables capture of the steady non-linear aerodynamics at high angles of attack. A simple methodology to include non-ideal induced effects due to wake periodicity and effective actuator disc area within the lifting line theory is included in the model. Low Reynolds number effects as well as the edge velocity correction required to account for different wing planform shapes are incorporated through appropriate modification of the wing section lift curve slope. The model has been successfully validated against measurements from revolving wing experiments and high order computational fluid dynamics simulations. Model predicted mean lift to weight ratio results have an average error of 4% compared to values from computational fluid dynamics for eight different insect cases. Application of an unmodified linear lifting line approach leads on average to a 60% overestimation in the mean lift force required for weight support, with most of the discrepancy due to use of linear aerodynamics. It is shown that on average for the eight insects considered, the induced drag contributes 22% of the total drag based on the mean cycle values and 29% of the total drag based on the mid half-stroke values.

  9. Bioavailability of two manufacturers' sustained-release quinidine gluconate tablets at steady state.

    Science.gov (United States)

    Zinny, M A; Taggart, W V

    1984-01-01

    Steady-state bioavailability of sustained-release quinidine gluconate tablets manufactured by two companies was compared in a crossover study. The tablets were Quinaglute Dura-Tabs, manufactured by Berlex Laboratories, Inc., and generic quinidine gluconate tablets, manufactured by Bolar Pharmaceutical Company. Sixteen healthy male volunteers were given multiple doses of the two products in randomized sequence. Blood samples were obtained immediately before administration of the seventh dose (hour 72) and at 1, 2, 3, 4, 5, 6, 8, 10, and 12 hours after administration. Plasma samples were assayed for quinidine content by high-performance liquid chromatography. The tablets manufactured by Berlex provided statistically significantly higher plasma levels during the second half of the dosing interval (six to 12 hours postdose). A 29% difference in plasma levels was observed between the products at the end of the dosing interval. The Bolar quinidine gluconate tablets had a statistically significant lower area under the curve (AUC). The greatest difference in AUC occurred during the last six hours of the dosing period. The six- to 12-hour AUC for the Bolar tablets was 24% less than that for Berlex tablets. The generic tablets also achieved peak plasma level 31% sooner than did Quinaglute Dura-Tabs. The pharmacokinetic characteristics of the two products at steady state indicate that the Bolar quinidine gluconate tablet exhibited a more rapid onset of peak plasma levels and a more rapid decline to minimum plasma levels. In summary, the data from this multiple-dose study, performed using commercially available material, indicate that differences exist in pharmacokinetic performance of the products. However, the exact correlation between pharmacokinetic data and clinical effectiveness has not been established.

  10. Comparison of Glucose Monitoring Methods during Steady-State Exercise in Women

    Directory of Open Access Journals (Sweden)

    Kelly L. Pritchett

    2012-09-01

    Full Text Available Data from Continuous Glucose Monitoring (CGM systems may help improve overall daily glycemia; however, the accuracy of CGM during exercise remains questionable. The objective of this single group experimental study was to compare CGM-estimated values to venous plasma glucose (VPG and capillary plasma glucose (CPG during steady-state exercise. Twelve recreationally active females without diabetes (aged 21.8 ± 2.4 years, from Central Washington University completed the study. CGM is used by individuals with diabetes, however the purpose of this study was to first validate the use of this device during exercise for anyone. Data were collected between November 2009 and April 2010. Participants performed two identical 45-min steady-state cycling trials (~60% Pmax on non-consecutive days. Glucose concentrations (CGM-estimated, VPG, and CPG values were measured every 5 min. Two carbohydrate gel supplements along with 360 mL of water were consumed 15 min into exercise. A product-moment correlation was used to assess the relationship and a Bland-Altman analysis determined error between the three glucose measurement methods. It was found that the CGM system overestimated mean VPG (mean absolute difference 17.4 mg/dL (0.97 mmol/L and mean CPG (mean absolute difference 15.5 mg/dL (0.86 mmol/L. Bland-Altman analysis displayed wide limits of agreement (95% confidence interval of 44.3 mg/dL (2.46 mmol/L (VPG compared with CGM and 41.2 mg/dL (2.29 mmol/L (CPG compared with CGM. Results from the current study support that data from CGM did not meet accuracy standards from the 15197 International Organization for Standardization (ISO.

  11. Busy Period of a Delayed-Service Single-Server Poisson Queue

    Science.gov (United States)

    Haghighi, A. M.; Mishev, D. P.; Chukova, S. S.

    2007-10-01

    In this paper we investigate busy period of a single-server Poisson queue with delayed-service. We will analyze this model by considering M/G/1 approximating a non-Markovian system. We obtain the distribution of the length of a busy period. Additionally, steady-state mean and distribution of the queue length will be obtained.

  12. Steady 3D Numerical Simulation of the Evaporator and Compensation Chamber of a Loop Heat Pipe

    Directory of Open Access Journals (Sweden)

    A. V. Nedayvozov

    2017-01-01

    Full Text Available The paper presents results of a steady three-dimensional numerical simulation of a flat evaporator and compensation chamber (CC of a loop heat pipe (LHP and describes a procedure of the thermal state calculation of the evaporator and the compensation chamber.The LHP is an efficient heat transfer device operating on the principle of evaporation-condensation cycle. It is successfully used in space technology and also to cool the heat-stressed components of electronic devices and computer equipment. The authors carried out a numerical study of the influence of the condensate pipeline length, immersed in water, on the thermal state of the evaporator and the compensation chamber.  The paper shows the influence of the mass forces field on the calculation results. Presents all the numerical studies carried out by the authors for a brass flat evaporator with a thermal load of 80 W. Water is used as a LHP heat-transfer fluid. Fields of temperature, pressure and velocity are presented for each design option.Based on the calculation results, the authors came to the following conclusions:Influence of the mass forces field for the LHP of this type is significant and leads to arising water vortex flow in the condensate pipeline and CC, thereby mixing and equalizing the water temperature in the CC and in the porous element, reducing the maximum temperature of the porous element;The increasing section length of the condensate pipeline in the CC leads to increasing velocity of the heat-transfer fluid in the CC and in the porous element, decreasing mixing zone of the condensate in the CC, and increasing temperature non-uniformity of the porous element.

  13. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    Science.gov (United States)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-01

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  14. Mineralizing urban net-zero water treatment: Phase II field ...

    Science.gov (United States)

    Net-zero water (NZW) systems, or water management systems achieving high recycling rates and low residuals generation so as to avoid water import and export, can also conserve energy used to heat and convey water, while economically restoring local eco-hydrology. However, design and operating experience are extremely limited. The objective of this paper is to present the results of the second phase of operation of an advanced oxidation-based NZW pilot system designed, constructed, and operated for a period of two years, serving an occupied four-person apartment. System water was monitored, either continuously or thrice daily, for routine water quality parameters, minerals, and MicroTox® in-vitro toxicity, and intermittently for somatic and male-specific coliphage, adenovirus, Cryptosporidium, Giardia, emerging organic constituents (non-quantitative), and the Florida drinking water standards. All 115 drinking water standards with the exception of bromate were met in this phase. Neither virus nor protozoa were detected in the treated water, with the exception of measurement of adenovirus genome copies attributed to accumulation of inactive genetic material in hydraulic dead zones. Chemical oxygen demand was mineralized to 90% in treatment. Total dissolved solids were maintained at ∼500 mg/L at steady state, partially through aerated aluminum electrocoagulation. Bromate accumulation is projected to be controlled by aluminum electrocoagulation with separate dispo

  15. Second Period Access Report

    DEFF Research Database (Denmark)

    Maisondieu, Christophe; Giebhardt, Jochen; Tetu, Amelie

    The work described in this publication has received support from the European Community - Research Infrastructure Action under the FP7 “Capacities” Specific Programme through grant agreement number 262552, MaRINET. Project Periodic Report. 2nd Period: October 2012 – March 2014 inclusive.......The work described in this publication has received support from the European Community - Research Infrastructure Action under the FP7 “Capacities” Specific Programme through grant agreement number 262552, MaRINET. Project Periodic Report. 2nd Period: October 2012 – March 2014 inclusive....

  16. Painful menstrual periods

    Science.gov (United States)

    Menstruation - painful; Dysmenorrhea; Periods - painful; Cramps - menstrual; Menstrual cramps ... a few days during each menstrual cycle. Painful menstruation is the leading cause of lost time from ...

  17. Characterization of interfacial reactions and oxide films on 316L stainless steel in various simulated PWR primary water environments

    Science.gov (United States)

    Chen, Junjie; Xiao, Qian; Lu, Zhanpeng; Ru, Xiangkun; Peng, Hao; Xiong, Qi; Li, Hongjuan

    2017-06-01

    The effect of water chemistry on the electrochemical and oxidizing behaviors of 316L SS was investigated in hydrogenated, deaerated and oxygenated PWR primary water at 310 °C. Water chemistry significantly influenced the electrochemical impedance spectroscopy parameters. The highest charge-transfer resistance and oxide-film resistance occurred in oxygenated water. The highest electric double-layer capacitance and constant phase element of the oxide film were in hydrogenated water. The oxide films formed in deaerated and hydrogenated environments were similar in composition but different in morphology. An oxide film with spinel outer particles and a compact and Cr-rich inner layer was formed in both hydrogenated and deaerated water. Larger and more loosely distributed outer oxide particles were formed in deaerated water. In oxygenated water, an oxide film with hematite outer particles and a porous and Ni-rich inner layer was formed. The reaction kinetics parameters obtained by electrochemical impedance spectroscopy measurements and oxidation film properties relating to the steady or quasi-steady state conditions in the time-period of measurements could provide fundamental information for understanding stress corrosion cracking processes and controlling parameters.

  18. Fast Estimation of Plant Steady State, with Application to Static RTO

    OpenAIRE

    Rodrigues, Diogo; Amrhein, Michael; Billeter, Julien; Bonvin, Dominique

    2016-01-01

    In the operation of continuous processes, many tasks require the knowledge of plant steady state at various operating points. This is for example the case in the context of kinetic modeling, response surface modeling and real-time optimization. If the computational techniques are in principle straightforward, the time needed to reach steady state represents the main limiting factor. This work proposes a novel way of speeding up the estimation of plant steady state through...

  19. Kinematical Analysis along Maximal Lactate Steady State Swimming Intensity

    Directory of Open Access Journals (Sweden)

    Pedro Figueiredo, Rafael Nazario, Marisa Sousa, Jailton Gregório Pelarigo, João Paulo Vilas-Boas, Ricardo Fernandes

    2014-09-01

    Full Text Available The purpose of this study was to conduct a kinematical analysis during swimming at the intensity corresponding to maximal lactate steady state (MLSS. Thirteen long distance swimmers performed, in different days, an intermittent incremental protocol of n x 200 m until exhaustion and two to four 30-min submaximal constant speed bouts to determine the MLSS. The video analysis, using APAS System (Ariel Dynamics Inc., USA, allowed determining the following relevant swimming determinants (in five moments of the 30-min test: 0, 25, 50, 75, and 100%: stroke rate, stroke length, trunk incline, intracyclic velocity variation, propelling efficiency, index of coordination and the time allotted to propulsion per distance unit. An ANOVA for repeated measures was used to compare the parameters mean values along each moment of analysis. Stoke rate tended to increase and stroke length to decrease along the test; a tendency to decrease was also found for intracyclic velocity variation and propelling efficiency whereas the index of coordination and the propulsive impulse remained stable during the MLSS test. It can be concluded that the MLSS is not only an intensity to maintain without a significant increase of blood lactate concentration, but a concomitant stability for some biomechanical parameters exists (after an initial adaptation. However, efficiency indicators seem to be more sensitive to changes occurring during swimming at this threshold intensity.

  20. Steady-State Thermoelastic Analytical Solutions for Insulated Pipelines

    Directory of Open Access Journals (Sweden)

    M. Fraldi

    2016-01-01

    Full Text Available A steady-state thermoelastic analytical solution for a multilayer hollow cylinder, composed of an arbitrary number of phases and subject to both radial pressure and temperature gradient, is presented. By assuming each phase to be homogeneous and thermally isotropic and by varying the mechanical and thermal constitutive parameters, a sensitivity analysis has been performed with the aim of finally applying the study to the mechanical behaviour of an industrial pipeline composed of three phases (steel, insulating coating, and polyethylene under the action of the above-mentioned load conditions. By making reference to a classical Hencky-von Mises criterion, the stress profiles along the thickness of the layers have been carried out, also localizing the onset of plasticity as a function of the temperature variations, material properties, and geometrical features characterizing the composite structure of interest. At the end, some numerical results of practical interest in the engineering applications have been specialized to three different insulated coating materials (expanded polyurethane, laminate glass, and syntactic foam, to highlight the cases in which thermal properties and loads can significantly interfere with the mechanical response in pipes, in terms of stresses, in this way suggesting possible strategies for avoiding unexpected failure and supporting the optimal structural design of these systems.

  1. Attentional modulation of auditory steady-state responses.

    Directory of Open Access Journals (Sweden)

    Yatin Mahajan

    Full Text Available Auditory selective attention enables task-relevant auditory events to be enhanced and irrelevant ones suppressed. In the present study we used a frequency tagging paradigm to investigate the effects of attention on auditory steady state responses (ASSR. The ASSR was elicited by simultaneously presenting two different streams of white noise, amplitude modulated at either 16 and 23.5 Hz or 32.5 and 40 Hz. The two different frequencies were presented to each ear and participants were instructed to selectively attend to one ear or the other (confirmed by behavioral evidence. The results revealed that modulation of ASSR by selective attention depended on the modulation frequencies used and whether the activation was contralateral or ipsilateral. Attention enhanced the ASSR for contralateral activation from either ear for 16 Hz and suppressed the ASSR for ipsilateral activation for 16 Hz and 23.5 Hz. For modulation frequencies of 32.5 or 40 Hz attention did not affect the ASSR. We propose that the pattern of enhancement and inhibition may be due to binaural suppressive effects on ipsilateral stimulation and the dominance of contralateral hemisphere during dichotic listening. In addition to the influence of cortical processing asymmetries, these results may also reflect a bias towards inhibitory ipsilateral and excitatory contralateral activation present at the level of inferior colliculus. That the effect of attention was clearest for the lower modulation frequencies suggests that such effects are likely mediated by cortical brain structures or by those in close proximity to cortex.

  2. Attentional modulation of auditory steady-state responses.

    Science.gov (United States)

    Mahajan, Yatin; Davis, Chris; Kim, Jeesun

    2014-01-01

    Auditory selective attention enables task-relevant auditory events to be enhanced and irrelevant ones suppressed. In the present study we used a frequency tagging paradigm to investigate the effects of attention on auditory steady state responses (ASSR). The ASSR was elicited by simultaneously presenting two different streams of white noise, amplitude modulated at either 16 and 23.5 Hz or 32.5 and 40 Hz. The two different frequencies were presented to each ear and participants were instructed to selectively attend to one ear or the other (confirmed by behavioral evidence). The results revealed that modulation of ASSR by selective attention depended on the modulation frequencies used and whether the activation was contralateral or ipsilateral. Attention enhanced the ASSR for contralateral activation from either ear for 16 Hz and suppressed the ASSR for ipsilateral activation for 16 Hz and 23.5 Hz. For modulation frequencies of 32.5 or 40 Hz attention did not affect the ASSR. We propose that the pattern of enhancement and inhibition may be due to binaural suppressive effects on ipsilateral stimulation and the dominance of contralateral hemisphere during dichotic listening. In addition to the influence of cortical processing asymmetries, these results may also reflect a bias towards inhibitory ipsilateral and excitatory contralateral activation present at the level of inferior colliculus. That the effect of attention was clearest for the lower modulation frequencies suggests that such effects are likely mediated by cortical brain structures or by those in close proximity to cortex.

  3. Development of the ITER Advanced Steady State and Hybrid Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    C.E. Kessel, D. Campbell, T. Casper, Y. Gribov, and J. Snipes

    2010-09-24

    Full discharge simulations are performed to examine the plasma current rampup, flattop and rampdown phases self-consistently with the poloidal field (PF) coils and their limitations, plasma transport evolution, and heating/current drive (H/CD) sources. Steady state scenarios are found that obtain 100% non-inductive current with Ip = 7.3-10.0 MA, βN ~ 2.5 for H98 = 1.6, Q’s range from 3 to 6, n/nGr = 0.75-1.0, and NB, IC, EC, and LH source have been examined. The scenarios remain within CS/PF coil limits by advancing the pre-magnetization by 40 Wb. Hybrid scenarios have been identified with 35-40% non-inductive current for Ip = 12.5 MA, H98 ~ 1.25, with q(0) reaching 1 at or after the end of rampup. The equilibrium operating space for the hybrid shows a large range of scenarios can be accommodated, and access 925-1300 s flattop burn durations.

  4. Ising game: Nonequilibrium steady states of resource-allocation systems

    Science.gov (United States)

    Xin, C.; Yang, G.; Huang, J. P.

    2017-04-01

    Resource-allocation systems are ubiquitous in the human society. But how external fields affect the state of such systems remains poorly explored due to the lack of a suitable model. Because the behavior of spins pursuing energy minimization required by physical laws is similar to that of humans chasing payoff maximization studied in game theory, here we combine the Ising model with the market-directed resource-allocation game, yielding an Ising game. Based on the Ising game, we show theoretical, simulative and experimental evidences for a formula, which offers a clear expression of nonequilibrium steady states (NESSs). Interestingly, the formula also reveals a convertible relationship between the external field (exogenous factor) and resource ratio (endogenous factor), and a class of saturation as the external field exceeds certain limits. This work suggests that the Ising game could be a suitable model for studying external-field effects on resource-allocation systems, and it could provide guidance both for seeking more relations between NESSs and equilibrium states and for regulating human systems by choosing NESSs appropriately.

  5. The steady aerodynamics of aerofoils with porosity gradients

    Science.gov (United States)

    Hajian, Rozhin; Jaworski, Justin W.

    2017-09-01

    This theoretical study determines the aerodynamic loads on an aerofoil with a prescribed porosity distribution in a steady incompressible flow. A Darcy porosity condition on the aerofoil surface furnishes a Fredholm integral equation for the pressure distribution, which is solved exactly and generally as a Riemann-Hilbert problem provided that the porosity distribution is Hölder-continuous. The Hölder condition includes as a subset any continuously differentiable porosity distributions that may be of practical interest. This formal restriction on the analysis is examined by a class of differentiable porosity distributions that approach a piecewise, discontinuous function in a certain parametric limit. The Hölder-continuous solution is verified in this limit against analytical results for partially porous aerofoils in the literature. Finally, a comparison made between the new theoretical predictions and experimental measurements of SD7003 aerofoils presented in the literature. Results from this analysis may be integrated into a theoretical framework to optimize turbulence noise suppression with minimal impact to aerodynamic performance.

  6. Classical quasi-steady state reduction-A mathematical characterization

    Science.gov (United States)

    Goeke, Alexandra; Walcher, Sebastian; Zerz, Eva

    2017-04-01

    We discuss parameter dependent polynomial ordinary differential equations that model chemical reaction networks. By classical quasi-steady state (QSS) reduction we understand the following familiar (heuristically motivated) mathematical procedure: Set the rate of change for certain (a priori chosen) variables equal to zero and use the resulting algebraic equations to obtain a system of smaller dimension for the remaining variables. This procedure will generally be valid only for certain parameter ranges. We start by showing that the reduction is accurate if and only if the corresponding parameter is what we call a QSS parameter value, and that the reduction is approximately accurate if and only if the corresponding parameter is close to a QSS parameter value. The QSS parameter values can be characterized by polynomial equations and inequations, hence parameter ranges for which QSS reduction is valid are accessible in an algorithmic manner. A defining characteristic of a QSS parameter value is that the algebraic variety defined by the QSS relations is invariant for the differential equation. A closer investigation of the associated systems shows the existence of further invariant sets; here singular perturbations enter the picture in a natural manner. We compare QSS reduction and singular perturbation reduction, and show that, while they do not agree in general, they do, up to lowest order in a small parameter, for a quite large and relevant class of examples. This observation, in turn, allows the computation of QSS reductions even in cases where an explicit resolution of the polynomial equations is not possible.

  7. A theory of nonequilibrium steady states in quantum chaotic systems

    Science.gov (United States)

    Wang, Pei

    2017-09-01

    Nonequilibrium steady state (NESS) is a quasistationary state, in which exist currents that continuously produce entropy, but the local observables are stationary everywhere. We propose a theory of NESS under the framework of quantum chaos. In an isolated quantum system whose density matrix follows a unitary evolution, there exist initial states for which the thermodynamic limit and the long-time limit are noncommutative. The density matrix \\hat ρ of these states displays a universal structure. Suppose that \\renewcommand{\\ket}[1]{{\\vert #1 >}} \\ketα and \\renewcommand{\\ket}[1]{{\\vert #1 >}} \\ketβ are different eigenstates of the Hamiltonian with energies E_α and E_β , respectively. \\renewcommand{\\bra}[1]{} \\braα\\hat ρ \\ketβ behaves as a random number which has zero mean. In thermodynamic limit, the variance of \\renewcommand{\\bra}[1]{} \\braα\\hat ρ \\ketβ is a smooth function of ≤ft\\vert E_α-E_β\\right\\vert , scaling as 1/≤ft\\vert E_α-E_β\\right\\vert 2 in the limit ≤ft\\vert E_α-E_β\\right\\vert \\to 0 . If and only if this scaling law is obeyed, the initial state evolves into NESS in the long time limit. We present numerical evidence of our hypothesis in a few chaotic models. Furthermore, we find that our hypothesis indicates the eigenstate thermalization hypothesis (ETH) for current operators in a bipartite system.

  8. Exergy optimization in a steady moving bed heat exchanger.

    Science.gov (United States)

    Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

    2009-04-01

    This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small.

  9. Attentional Modulation of Auditory Steady-State Responses

    Science.gov (United States)

    Mahajan, Yatin; Davis, Chris; Kim, Jeesun

    2014-01-01

    Auditory selective attention enables task-relevant auditory events to be enhanced and irrelevant ones suppressed. In the present study we used a frequency tagging paradigm to investigate the effects of attention on auditory steady state responses (ASSR). The ASSR was elicited by simultaneously presenting two different streams of white noise, amplitude modulated at either 16 and 23.5 Hz or 32.5 and 40 Hz. The two different frequencies were presented to each ear and participants were instructed to selectively attend to one ear or the other (confirmed by behavioral evidence). The results revealed that modulation of ASSR by selective attention depended on the modulation frequencies used and whether the activation was contralateral or ipsilateral. Attention enhanced the ASSR for contralateral activation from either ear for 16 Hz and suppressed the ASSR for ipsilateral activation for 16 Hz and 23.5 Hz. For modulation frequencies of 32.5 or 40 Hz attention did not affect the ASSR. We propose that the pattern of enhancement and inhibition may be due to binaural suppressive effects on ipsilateral stimulation and the dominance of contralateral hemisphere during dichotic listening. In addition to the influence of cortical processing asymmetries, these results may also reflect a bias towards inhibitory ipsilateral and excitatory contralateral activation present at the level of inferior colliculus. That the effect of attention was clearest for the lower modulation frequencies suggests that such effects are likely mediated by cortical brain structures or by those in close proximity to cortex. PMID:25334021

  10. Glaucoma affects steady state VEP contrast thresholds before psychophysics.

    Science.gov (United States)

    Vaegan; Rahman, Anmar M A; Sanderson, Gordon F

    2008-07-01

    Frequency doubling technology (FDT) is a recent psychophysical test for glaucoma. It measures the contrast threshold to low spatial frequency, high temporal frequency sinusoidal luminance profile bars. We wanted to confirm, with stricter controls, Vaegan and Hollow's report that contrast thresholds of steady state visual evoked potentials (ssVEPs) to a stimulus resembling the central field of the FDT test was more sensitive to glaucoma than the subjective threshold to the same stimulus and to start to optimize the technique. A double masked trial using 57 eyes of 42 subjects. Both thresholds were estimated by modified binary search. In psychophysical testing, subjects were given a two alternative forced choice task. In ssVEP testing a significant signal in any one of eight channels was deemed to be a detection. In some subjects electrode positions were compared, both eyes were tested, tests were repeated to estimate reliability, stimulus frequencies were varied or full contrast functions were obtained. Thresholds and percent abnormal increased as a function of glaucoma severity for ssVEPs but not for psychophysics. Both threshold measures were reliable. Interocular correlations were low. SsVEP amplitude against contrast functions had similar thresholds to those found by modified binary search. The data was too irregular for individual thresholds to be estimated from a fitted exponential. Amplitudes were greatest at 7 to 10 Hz, psychophysical thresholds at 18.29 Hz, when formal controls were used, as they had in a less controlled previous study at 7.14 Hz.

  11. Lithium surface operating under steady-state power load

    Energy Technology Data Exchange (ETDEWEB)

    Khripunov, B.I. E-mail: boris@nfi.kiae.ru; Petrov, V.B.; Shapkin, V.V.; Antonov, N.V.; Pleshakov, A.S.; Rupyshev, A.S.; Prokhorov, D.Yu.; Evtikhin, V.A.; Lyublinsky, I.E.; Vertkov, V.V

    2003-04-01

    A liquid lithium surface is considered for application in divertor of a fusion tokamak-reactor. Lithium surface has been realized in experimental mock-ups and its operation has been demonstrated under high power load at reactor relevant heat fluxes. Lithium targets have been developed on the basis of capillary pore structures. A vertical working surface was investigated under steady-state electron beam. The range of power loads 1-50 MW/m{sup 2} was covered by the studies. Long-duration experiments were performed on thermally stabilized targets at 1-10 MW/m{sup 2}. Evaporation was shown to be efficient mechanism of power removal and a high lithium mass loss rate was measured. Operation of the facility with plasma at 0.2 g/s of lithium flow was shown. The problem of lithium balance in divertor and SOL is discussed. Pumping of lithium is possible by solid and liquid metal wall structures in reactor conditions in the divertor channel.

  12. The physiology of submaximal exercise: The steady state concept.

    Science.gov (United States)

    Ferretti, Guido; Fagoni, Nazzareno; Taboni, Anna; Bruseghini, Paolo; Vinetti, Giovanni

    2017-12-01

    The steady state concept implies that the oxygen flow is invariant and equal at each level along the respiratory system. The same is the case with the carbon dioxide flow. This condition has several physiological consequences, which are analysed. First, we briefly discuss the mechanical efficiency of exercise and the energy cost of human locomotion, as well as the roles played by aerodynamic work and frictional work. Then we analyse the equations describing the oxygen flow in lungs and in blood, the effects of ventilation and of the ventilation - perfusion inequality, and the interaction between diffusion and perfusion in the lungs. The cardiovascular responses sustaining gas flow increase in blood are finally presented. An equation linking ventilation, circulation and metabolism is developed, on the hypothesis of constant oxygen flow in mixed venous blood. This equation tells that, if the pulmonary respiratory quotient stays invariant, any increase in metabolic rate is matched by a proportional increase in ventilation, but by a less than proportional increase in cardiac output. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Flavour fields in steady state: stress tensor and free energy

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Avik; Kundu, Arnab [Theory Division, Saha Institute of Nuclear Physics,1/AF Bidhannagar, Kolkata- 700064 (India); Kundu, Sandipan [Department of Physics, Cornell University,Ithaca, New York, 14853 (United States)

    2016-02-16

    The dynamics of a probe brane in a given gravitational background is governed by the Dirac-Born-Infeld action. The corresponding open string metric arises naturally in studying the fluctuations on the probe. In Gauge-String duality, it is known that in the presence of a constant electric field on the worldvolume of the probe, the open string metric acquires an event horizon and therefore the fluctuation modes on the probe experience an effective temperature. In this article, we bring together various properties of such a system to a formal definition and a subsequent narration of the effective thermodynamics and the stress tensor of the corresponding flavour fields, also including a non-vanishing chemical potential. In doing so, we point out a potentially infinitely-degenerate scheme-dependence of regularizing the free energy, which nevertheless yields a universal contribution in certain cases. This universal piece appears as the coefficient of a log-divergence in free energy when a space-filling probe brane is embedded in AdS{sub d+1}-background, for d=2,4, and is related to conformal anomaly. For the special case of d=2, the universal factor has a striking resemblance to the well-known heat current formula in (1+1)-dimensional conformal field theory in steady-state, which endows a plausible physical interpretation to it. Interestingly, we observe a vanishing conformal anomaly in d=6.

  14. Steady state quantum discord for circularly accelerated atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jiawei, E-mail: hujiawei@nbu.edu.cn [Center for Nonlinear Science and Department of Physics, Ningbo University, Ningbo, Zhejiang 315211 (China); Yu, Hongwei, E-mail: hwyu@hunnu.edu.cn [Center for Nonlinear Science and Department of Physics, Ningbo University, Ningbo, Zhejiang 315211 (China); Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China)

    2015-12-15

    We study, in the framework of open quantum systems, the dynamics of quantum entanglement and quantum discord of two mutually independent circularly accelerated two-level atoms in interaction with a bath of fluctuating massless scalar fields in the Minkowski vacuum. We assume that the two atoms rotate synchronically with their separation perpendicular to the rotating plane. The time evolution of the quantum entanglement and quantum discord of the two-atom system is investigated. For a maximally entangled initial state, the entanglement measured by concurrence diminishes to zero within a finite time, while the quantum discord can either decrease monotonically to an asymptotic value or diminish to zero at first and then followed by a revival depending on whether the initial state is antisymmetric or symmetric. When both of the two atoms are initially excited, the generation of quantum entanglement shows a delayed feature, while quantum discord is created immediately. Remarkably, the quantum discord for such a circularly accelerated two-atom system takes a nonvanishing value in the steady state, and this is distinct from what happens in both the linear acceleration case and the case of static atoms immersed in a thermal bath.

  15. The steady aerodynamics of aerofoils with porosity gradients.

    Science.gov (United States)

    Hajian, Rozhin; Jaworski, Justin W

    2017-09-01

    This theoretical study determines the aerodynamic loads on an aerofoil with a prescribed porosity distribution in a steady incompressible flow. A Darcy porosity condition on the aerofoil surface furnishes a Fredholm integral equation for the pressure distribution, which is solved exactly and generally as a Riemann-Hilbert problem provided that the porosity distribution is Hölder-continuous. The Hölder condition includes as a subset any continuously differentiable porosity distributions that may be of practical interest. This formal restriction on the analysis is examined by a class of differentiable porosity distributions that approach a piecewise, discontinuous function in a certain parametric limit. The Hölder-continuous solution is verified in this limit against analytical results for partially porous aerofoils in the literature. Finally, a comparison made between the new theoretical predictions and experimental measurements of SD7003 aerofoils presented in the literature. Results from this analysis may be integrated into a theoretical framework to optimize turbulence noise suppression with minimal impact to aerodynamic performance.

  16. Quasi-steady state aerodynamics of the cheetah tail.

    Science.gov (United States)

    Patel, Amir; Boje, Edward; Fisher, Callen; Louis, Leeann; Lane, Emily

    2016-08-15

    During high-speed pursuit of prey, the cheetah (Acinonyx jubatus) has been observed to swing its tail while manoeuvring (e.g. turning or braking) but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities. © 2016. Published by The Company of Biologists Ltd.

  17. Quasi-steady state aerodynamics of the cheetah tail

    Directory of Open Access Journals (Sweden)

    Amir Patel

    2016-08-01

    Full Text Available During high-speed pursuit of prey, the cheetah (Acinonyx jubatus has been observed to swing its tail while manoeuvring (e.g. turning or braking but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities.

  18. LBM-LES Simulation of the Transient Asymmetric Flow and Free Surface Fluctuations under Steady Operating Conditions of Slab Continuous Casting Process

    Science.gov (United States)

    Zhao, Peng; Li, Qiang; Kuang, S. B.; Zou, Zongshu

    2017-02-01

    Transient flow structures in a continuous casting mold can strongly influence the slag entrainment in liquid steel and the bubbles capture in the initial solidified shell, both of which are associated with the quality of the final product. This paper presents a numerical study of the turbulent flow with a top free surface in the continuous casting mold at a meso-scale level by a three-dimensional combined approach of Free Surface Lattice Boltzmann Method and Large Eddy Simulation (FSLBM-LES). The validity of the model is verified by the good agreement between the calculated results and the measurements from various water experiments in terms of the flow velocity and free surface profile. The mathematical model is then used to reveal the transient and spatiotemporal asymmetric characteristics associated with the transient flow field and the free surface fluctuation, although the steady state operation is considered during the continuous casting process. The results show that the locations of the jets of liquid steel from the two out ports of the Submerged Entry Nozzle (SEN) always fluctuate alternatively within a certain range, and periodically deviate from the design angle of the SEN within the same time period. The oscillating behavior of the jets promotes the asymmetric flow patterns and multi-scale vortices at both sides of the SEN. By introducing the Q-criterion in the results analysis, the formation, development, and shedding of the coherent structure (CS) of the turbulent flow are quantitatively characterized. The interaction between the transient flow patterns and the fluctuations of the top free surface as well as the evolution of the transient profile and velocities of the free surface are also demonstrated. The results obtained from the current study suggest that the FSLBM-LES model offers a promising way to study the complex flows and related transfer phenomena in the continuous casting process.

  19. Computational multiple steady states for enzymatic esterification of ethanol and oleic acid in an isothermal CSTR.

    Science.gov (United States)

    Ho, Pang-Yen; Chuang, Guo-Syong; Chao, An-Chong; Li, Hsing-Ya

    2005-05-01

    The capacity of complex biochemical reaction networks (consisting of 11 coupled non-linear ordinary differential equations) to show multiple steady states, was investigated. The system involved esterification of ethanol and oleic acid by lipase in an isothermal continuous stirred tank reactor (CSTR). The Deficiency One Algorithm and the Subnetwork Analysis were applied to determine the steady state multiplicity. A set of rate constants and two corresponding steady states are computed. The phenomena of bistability, hysteresis and bifurcation are discussed. Moreover, the capacity of steady state multiplicity is extended to the family of the studied reaction networks.

  20. An analytical description of balanced steady-state free precession with finite radio-frequency excitation.

    Science.gov (United States)

    Bieri, Oliver

    2011-02-01

    Conceptually, the only flaw in the standard steady-state free precession theory is the assumption of quasi-instantaneous radio-frequency pulses, and 10-20% signal deviations from theory are observed for common balanced steady-state free precession protocols. This discrepancy in the steady-state signal can be resolved by a simple T(2) substitution taking into account reduced transverse relaxation effects during finite radio-frequency excitation. However, finite radio-frequency effects may also affect the transient phase of balanced steady-state free precession, its contrast or its spin-echo nature and thereby have an adverse effect on common steady-state free precession magnetization preparation methods. As a result, an in-depth understanding of finite radio-frequency effects is not only of fundamental theoretical interest but also has direct practical implications. In this article, an analytical solution for balanced steady-state free precession with finite radio-frequency pulses is derived for the transient phase (under ideal conditions) and in the steady state demonstrating that balanced steady-state free precession key features are preserved but revealing an unexpected dependency of finite radio-frequency effects on relaxation times for the transient decay. Finally, the mathematical framework reveals that finite radio-frequency theory can be understood as a generalization of alternating repetition time and fluctuating equilibrium steady-state free precession sequence schemes. Copyright © 2010 Wiley-Liss, Inc.

  1. The Living Periodic Table

    Science.gov (United States)

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  2. Application of hybrid methodology to rotors in steady and maneuvering flight

    Science.gov (United States)

    Rajmohan, Nischint

    Helicopters are versatile flying machines that have capabilities that are unparalleled by fixed wing aircraft, such as operating in hover, performing vertical takeoff and landing on unprepared sites. This makes their use especially desirable in military and search-and-rescue operations. However, modern helicopters still suffer from high levels of noise and vibration caused by the physical phenomena occurring in the vicinity of the rotor blades. Therefore, improvement in rotorcraft design to reduce the noise and vibration levels requires understanding of the underlying physical phenomena, and accurate prediction capabilities of the resulting rotorcraft aeromechanics. The goal of this research is to study the aeromechanics of rotors in steady and maneuvering flight using hybrid Computational Fluid Dynamics (CFD) methodology. The hybrid CFD methodology uses the Navier-Stokes equations to solve the flow near the blade surface but the effect of the far wake is computed through the wake model. The hybrid CFD methodology is computationally efficient and its wake modeling approach is nondissipative making it an attractive tool to study rotorcraft aeromechanics. Several enhancements were made to the CFD methodology and it was coupled to a Computational Structural Dynamics (CSD) methodology to perform a trimmed aeroelastic analysis of a rotor in forward flight. The coupling analyses, both loose and tight were used to identify the key physical phenomena that affect rotors in different steady flight regimes. The modeling enhancements improved the airloads predictions for a variety of flight conditions. It was found that the tightly coupled method did not impact the loads significantly for steady flight conditions compared to the loosely coupled method. The coupling methodology was extended to maneuvering flight analysis by enhancing the computational and structural models to handle non-periodic flight conditions and vehicle motions in time accurate mode. The flight test

  3. On some periodicity effects

    DEFF Research Database (Denmark)

    Sorokin, Sergey V.

    2015-01-01

    The talk is concerned with the modelling of wave propagation in and vibration of periodic elastic structures. Although analysis of wave-guide properties of infinite periodic structures is a well establish research subject, some issues have not yet been fully addressed in the literature. The aim...... of the talk is to illustrate these issues in simple examples and to discuss possible applications and generalisations. First, the eigenfrequency spectra of finite periodic structures are compared with the location of stop-bands for their infinite counterparts for a hierarchy of four mathematical models....... In each case, special attention is paid to eigenfrequencies and eigenmodes of a single periodicity cell with appropriate boundary conditions. The influence of the amount of periodicity cells in a finite compound structure on its eigenfrequency spectrum is analyzed. Several features common...

  4. Periods and Nori motives

    CERN Document Server

    Huber, Annette

    2017-01-01

    This book casts the theory of periods of algebraic varieties in the natural setting of Madhav Nori’s abelian category of mixed motives. It develops Nori’s approach to mixed motives from scratch, thereby filling an important gap in the literature, and then explains the connection of mixed motives to periods, including a detailed account of the theory of period numbers in the sense of Kontsevich-Zagier and their structural properties. Period numbers are central to number theory and algebraic geometry, and also play an important role in other fields such as mathematical physics. There are long-standing conjectures about their transcendence properties, best understood in the language of cohomology of algebraic varieties or, more generally, motives. Readers of this book will discover that Nori’s unconditional construction of an abelian category of motives (over fields embeddable into the complex numbers) is particularly well suited for this purpose. Notably, Kontsevich's formal period algebra represents a to...

  5. Response of surface buoy moorings in steady and wave flows

    Digital Repository Service at National Institute of Oceanography (India)

    Anand, N.M.; Nayak, B.U.; SanilKumar, V.

    A numerical model has been developed to evaluate the dynamics of surface buoy mooring systems under wave and current loading. System tension response and variation of tension in the mooring line at various depths have been evaluated for deep water...

  6. Theory of Periodic Conjugate Heat Transfer

    CERN Document Server

    Zudin, Yuri B

    2012-01-01

    This book presents the theory of periodic conjugate heat transfer in a detailed way. The effects of thermophysical properties and geometry of a solid body on the commonly used and experimentally determined heat transfer coefficient are analytically presented from a general point of view. The main objective of the book is a simplified description of the interaction between a solid body and a fluid as a boundary value problem of the heat conduction equation for the solid body. At the body surface, the true heat transfer coefficient is composed of two parts: the true mean value resulting from the solution of the steady state heat transfer problem and a periodically variable part, the periodic time and length to describe the oscillatory hydrodynamic effects. The second edition is extended by (i) the analysis of stability boundaries in helium flow at supercritical conditions in a heated channel with respect to the interaction between a solid body and a fluid; (ii) a periodic model and a method of heat transfer sim...

  7. Formulating the spring discharge-function for the recession period ...

    Indian Academy of Sciences (India)

    Prediction of spring water availability during the recession period is the key to its proper management. ... The efficiency of the formulated master discharge function of the spring for the recession period has been ... The only feasible answer to this water scarcity problem in recession period is to store it when it is in excess ...

  8. Mean-periodic functions

    Directory of Open Access Journals (Sweden)

    Carlos A. Berenstein

    1980-01-01

    Full Text Available We show that any mean-periodic function f can be represented in terms of exponential-polynomial solutions of the same convolution equation f satisfies, i.e., u∗f=0(μ∈E′(ℝn. This extends to n-variables the work of L. Schwartz on mean-periodicity and also extends L. Ehrenpreis' work on partial differential equations with constant coefficients to arbitrary convolutors. We also answer a number of open questions about mean-periodic functions of one variable. The basic ingredient is our work on interpolation by entire functions in one and several complex variables.

  9. Steady-State Thermal-Hydraulics Analyses for the Conversion of the BR2 Reactor to LEU

    Energy Technology Data Exchange (ETDEWEB)

    Licht, J. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Bergeron, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Dionne, B. [Argonne National Lab. (ANL), Argonne, IL (United States); Van den Branden, G. [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium); Kalcheva, S [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium); Sikik, E [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium); Koonen, E [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium)

    2016-09-01

    BR2 is a research reactor used for radioisotope production and materials testing. It’s a tank-in-pool type reactor cooled by light water and moderated by beryllium and light water. The reactor core consists of a beryllium moderator forming a matrix of 79 hexagonal prisms in a hyperboloid configuration; each having a central bore that can contain a variety of different components such as a fuel assembly, a control or regulating rod, an experimental device, or a beryllium or aluminum plug. Based on a series of tests, the BR2 operation is currently limited to a maximum allowable heat flux of 470 W/cm2 to ensure fuel plate integrity during steady-state operation and after a loss-of-flow/loss-of-pressure accident. A feasibility study for the conversion of the BR2 reactor from highly-enriched uranium (HEU) to low-enriched uranium (LEU) fuel was previously performed to verify it can operate safely at the same maximum nominal steady-state heat flux. An assessment was also performed to quantify the heat fluxes at which the onset of flow instability and critical heat flux occur for each fuel type. This document updates and expands these results for the current representative core configuration (assuming a fresh beryllium matrix) by evaluating the onset of nucleate boiling (ONB), onset of fully developed nucleate boiling (FDNB), onset of flow instability (OFI) and critical heat flux (CHF).

  10. On the computation of steady, self - consistent spherical dynamos

    Science.gov (United States)

    Fearn, D. R.; Proctor, M. R. E.

    In an earlier paper (Fearn and Proctor, 1984) we described results from a preliminary model of a spherical hydromagnetic dynamo driven by convection. An iterative approach was used. Starting from some guess for the mean toroidal field B we solved for the form of the convective instability in the presence of this field. The mean e.m.f. E [defined in (2.13)] associated with the convection was calculated, and from this, an-effect was constructed (=E/B). We then solved a mean field-dynamo model to produce a new "B". This cycle was repeated until B converged. For a preliminary investigation, there were good reasons for using an-effect formalism. However, a more straightforward and physically more realistic approach is to use the e.m.f. E directly to force the mean field dynamo. This "EΩ-dynamo" is used here. The converged results of Fearn and Proctor (1984) are successfully reproduced and in addition we have found converged steady dynamos in the absence of any poloidal flow (cf. Roberts, 1972). Our iterative dynamo is still far from being completely self-consistent since several parameters and the mean fluid flow have had to be arbitrarily prescribed. The next step is to incorporate more of the dynamics. We use the mean momentum equation to determine the mean flow and, in particular, apply Taylor's (1963) constraint to determine the otherwise arbitrary geostrophic flow UG(s)? The EΩ-dynamo permits this to be done with relative ease (see Fearn and Proctor, 1987). No converged results were found. Solutions either became too detailed to resolve, magnetic instabilities became present, or the solution jumped between two different modes of convection.

  11. Phencyclidine Disrupts the Auditory Steady State Response in Rats.

    Directory of Open Access Journals (Sweden)

    Emma Leishman

    Full Text Available The Auditory Steady-State Response (ASSR in the electroencephalogram (EEG is usually reduced in schizophrenia (SZ, particularly to 40 Hz stimulation. The gamma frequency ASSR deficit has been attributed to N-methyl-D-aspartate receptor (NMDAR hypofunction. We tested whether the NMDAR antagonist, phencyclidine (PCP, produced similar ASSR deficits in rats. EEG was recorded from awake rats via intracranial electrodes overlaying the auditory cortex and at the vertex of the skull. ASSRs to click trains were recorded at 10, 20, 30, 40, 50, and 55 Hz and measured by ASSR Mean Power (MP and Phase Locking Factor (PLF. In Experiment 1, the effect of different subcutaneous doses of PCP (1.0, 2.5 and 4.0 mg/kg on the ASSR in 12 rats was assessed. In Experiment 2, ASSRs were compared in PCP treated rats and control rats at baseline, after acute injection (5 mg/kg, following two weeks of subchronic, continuous administration (5 mg/kg/day, and one week after drug cessation. Acute administration of PCP increased PLF and MP at frequencies of stimulation below 50 Hz, and decreased responses at higher frequencies at the auditory cortex site. Acute administration had a less pronounced effect at the vertex site, with a reduction of either PLF or MP observed at frequencies above 20 Hz. Acute effects increased in magnitude with higher doses of PCP. Consistent effects were not observed after subchronic PCP administration. These data indicate that acute administration of PCP, a NMDAR antagonist, produces an increase in ASSR synchrony and power at low frequencies of stimulation and a reduction of high frequency (> 40 Hz ASSR activity in rats. Subchronic, continuous administration of PCP, on the other hand, has little impact on ASSRs. Thus, while ASSRs are highly sensitive to NMDAR antagonists, their translational utility as a cross-species biomarker for NMDAR hypofunction in SZ and other disorders may be dependent on dose and schedule.

  12. Phencyclidine Disrupts the Auditory Steady State Response in Rats.

    Science.gov (United States)

    Leishman, Emma; O'Donnell, Brian F; Millward, James B; Vohs, Jenifer L; Rass, Olga; Krishnan, Giri P; Bolbecker, Amanda R; Morzorati, Sandra L

    2015-01-01

    The Auditory Steady-State Response (ASSR) in the electroencephalogram (EEG) is usually reduced in schizophrenia (SZ), particularly to 40 Hz stimulation. The gamma frequency ASSR deficit has been attributed to N-methyl-D-aspartate receptor (NMDAR) hypofunction. We tested whether the NMDAR antagonist, phencyclidine (PCP), produced similar ASSR deficits in rats. EEG was recorded from awake rats via intracranial electrodes overlaying the auditory cortex and at the vertex of the skull. ASSRs to click trains were recorded at 10, 20, 30, 40, 50, and 55 Hz and measured by ASSR Mean Power (MP) and Phase Locking Factor (PLF). In Experiment 1, the effect of different subcutaneous doses of PCP (1.0, 2.5 and 4.0 mg/kg) on the ASSR in 12 rats was assessed. In Experiment 2, ASSRs were compared in PCP treated rats and control rats at baseline, after acute injection (5 mg/kg), following two weeks of subchronic, continuous administration (5 mg/kg/day), and one week after drug cessation. Acute administration of PCP increased PLF and MP at frequencies of stimulation below 50 Hz, and decreased responses at higher frequencies at the auditory cortex site. Acute administration had a less pronounced effect at the vertex site, with a reduction of either PLF or MP observed at frequencies above 20 Hz. Acute effects increased in magnitude with higher doses of PCP. Consistent effects were not observed after subchronic PCP administration. These data indicate that acute administration of PCP, a NMDAR antagonist, produces an increase in ASSR synchrony and power at low frequencies of stimulation and a reduction of high frequency (> 40 Hz) ASSR activity in rats. Subchronic, continuous administration of PCP, on the other hand, has little impact on ASSRs. Thus, while ASSRs are highly sensitive to NMDAR antagonists, their translational utility as a cross-species biomarker for NMDAR hypofunction in SZ and other disorders may be dependent on dose and schedule.

  13. The study of candidate materials in steady state plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khripunov, B.I. [Inst. of Nuclear Fusion, Russian Research Center ``Kurchatov Inst.``, Moscow (Russian Federation); Shapkin, V.V. [Inst. of Nuclear Fusion, Russian Research Center ``Kurchatov Inst.``, Moscow (Russian Federation); Petrov, V.B. [Inst. of Nuclear Fusion, Russian Research Center ``Kurchatov Inst.``, Moscow (Russian Federation); Antonov, N.V. [Inst. of Nuclear Fusion, Russian Research Center ``Kurchatov Inst.``, Moscow (Russian Federation)

    1995-12-31

    The choice of the materials for the ITER and future reactors first wall till now is restricted to three basic elements - carbon, beryllium, tungsten. New materials are being developed on this basis for plasma facing components. Here carbon based materials and tungsten are investigated under steady state plasma in the linear simulator LENTA. Erosion and hydrogen isotope retention are of the most interest in this study. High flux deuterium plasma is produced in beam-plasma discharge (20 kW): ion flux 10{sup 17}-10{sup 19} ion/cm{sup 2}s, electron temperature 15-30 eV, electron density up to 10{sup 13}cm{sup -3}. Ion fluence {approx}10{sup 22}ion/cm{sup 2} is achieved in several hours expositions. Bombarding ion energy is in the interval from several hundreds eV to {approx}20 eV, it can be controlled by bias voltage; this range covers the threshold values for physical sputtering and is actually of great interest. Experiments have been performed with RG-Ti, VPG, CFC Russian graphites and American POCO at 1100C. Erosion of graphites is found to be fluence dependent for values <10{sup 21}ion/cm{sup 2} and is almost constant at 10{sup 21}-10{sup 22}ion/cm{sup 2}. The erosion yield was 0.06-0.08 for all these graphites. Very low deuterium retention in RG-Ti was found. High tungsten erosion was observed in the experiments with samples biasing in the range 0-(-100)V just below the threshold value for physical sputtering by deuterium ions. (orig.).

  14. A steady-state model of the lunar ejecta cloud

    Science.gov (United States)

    Christou, Apostolos

    2014-05-01

    Every airless body in the solar system is surrounded by a cloud of ejecta produced by the impact of interplanetary meteoroids on its surface [1]. Such ``dust exospheres'' have been observed around the Galilean satellites of Jupiter [2,3]. The prospect of long-term robotic and human operations on the Moon by the US and other countries has rekindled interest on the subject [4]. This interest has culminated with the - currently ongoing - investigation of the Moon's dust exosphere by the LADEE spacecraft [5]. Here a model is presented of a ballistic, collisionless, steady state population of ejecta launched vertically at randomly distributed times and velocities and moving under constant gravity. Assuming a uniform distribution of launch times I derive closed form solutions for the probability density functions (pdfs) of the height distribution of particles and the distribution of their speeds in a rest frame both at the surface and at altitude. The treatment is then extended to particle motion with respect to a moving platform such as an orbiting spacecraft. These expressions are compared with numerical simulations under lunar surface gravity where the underlying ejection speed distribution is (a) uniform (b) a power law. I discuss the predictions of the model, its limitations, and how it can be validated against near-surface and orbital measurements.[1] Gault, D. Shoemaker, E.M., Moore, H.J., 1963, NASA TN-D 1767. [2] Kruger, H., Krivov, A.V., Hamilton, D. P., Grun, E., 1999, Nature, 399, 558. [3] Kruger, H., Krivov, A.V., Sremcevic, M., Grun, E., 2003, Icarus, 164, 170. [4] Grun, E., Horanyi, M., Sternovsky, Z., 2011, Planetary and Space Science, 59, 1672. [5] Elphic, R.C., Hine, B., Delory, G.T., Salute, J.S., Noble, S., Colaprete, A., Horanyi, M., Mahaffy, P., and the LADEE Science Team, 2014, LPSC XLV, LPI Contr. 1777, 2677.

  15. The Periodic Table CD.

    Science.gov (United States)

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  16. Setting the Periodic Table.

    Science.gov (United States)

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  17. From steady-state to climatically driven denudation across the Central Andes - SE Peru

    Science.gov (United States)

    Ruiz, G.; Carlotto, V.; Andriessen, P.

    2009-04-01

    To better constrain the orogenic growth of the Andean chain, we investigated the time-Temperature paths of bedrocks from the two morpho-structural highs of the Central Andes that are separated by the vanishing Altiplano, i.e. the Eastern and Western Cordilleras of SE Peru. The Western Cordillera is a volcanic to volcano-detrital chain that developed ~40-35 Ma ago and is characterized by a 4000m high mean altitude whose origin is poorly constrained. Fission-Track data on apatite and zircon crystals extracted from an Eocene pluton yield ages comprised between 24 and 14 Ma, and 38 and 30 Ma respectively. One of the noteworthy aspects of the data is that analyses reveal a steady-state phase of exhumation from the late Eocene to at least the middle Miocene (38-14 Ma) with no disruption of the exhumation path since 38 Ma either by sedimentary burial and/or rapid exhumation. The uplift of the Western Cordillera was thus probably steady since, avoiding the deposition of foreland basin sequences as in the Altiplano region. Further east, Apatite Fission-Track ages are much younger and range between 7.6 and 2.5 Ma for the Eastern Cordillera and between 11.2 and 1.5 Ma for the Sub-Andean Zone. Age-altitude relationships suggest that denudation increased from a more quiescent Late Miocene period to a high rate of 0.8 km/my for the Pliocene. Such abrupt change is supported by a net in sediment accumulation rates in the Andean Amazon Basin but as far as offshore the Amazon fan. A global climate change is usually invoked for high Pliocene rates; however it post-dated a documented period of surface uplift in the Eastern Andes. Denudation patterns are much contrasted across the Andes of SE Peru. The western Cordillera, despite significant topography and deep river valleys in the studied area, still yield information that suggest a steady and slow uplift from the late Eocene until at least the middle Miocene. We thus propose a coupled scenario: first the Andean orographic barrier

  18. Determining Steady-state Tissue Residues for Invertebrates in Contaminated Sediment

    Science.gov (United States)

    2010-05-01

    ER D C/ EL T R -1 0 -2 Dredging Operations and Environmental Research Program Determining Steady-state Tissue Residues for Invertebrates ...2010 Determining Steady-state Tissue Residues for Invertebrates in Contaminated Sediment Alan J. Kennedy, Guilherme R. Lotufo, Jeffery A. Steevens...involves quantification of compounds in tissues via laboratory bioaccumulation exposures of benthic invertebrates . However, the standard 28-day expo

  19. AN EFFICIENT CODE TO COMPUTE NONPARALLEL STEADY FLOWS AND THEIR LINEAR-STABILITY

    NARCIS (Netherlands)

    DIJKSTRA, HA; MOLEMAKER, MJ; VANDERPLOEG, A; BOTTA, EFF

    A simple, fast and efficient algorithm to compute steady non-parallel flows and their linear stability in parameter space is described. The pseudo-arclength continuation method is used to trace branches of steady states as one of the parameters is varied. To determine the linear stability of each

  20. The steady state of a particle in a vibrating box and possible ...

    Indian Academy of Sciences (India)

    In particular, the parameter range is found in which the particle oscillates between the walls in steady state as if the wall was static and it is showed that for these parameter ranges the particle settles to this steady state for all initial conditions. It is proposed that this phenomenon can be used to bunch charged particles in ...

  1. 40 CFR 86.1362-2007 - Steady-state testing with a ramped-modal cycle.

    Science.gov (United States)

    2010-07-01

    ... Exhaust Test Procedures § 86.1362-2007 Steady-state testing with a ramped-modal cycle. This section... testing the engine on a dynamometer with the following ramped-modal duty cycle to determine whether it... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Steady-state testing with a ramped...

  2. Universal, computer facilitated, steady state oscillator, closed loop analysis theory and some applications to precision oscillators

    Science.gov (United States)

    Parzen, Benjamin

    1992-01-01

    The theory of oscillator analysis in the immittance domain should be read in conjunction with the additional theory presented here. The combined theory enables the computer simulation of the steady state oscillator. The simulation makes the calculation of the oscillator total steady state performance practical, including noise at all oscillator locations. Some specific precision oscillators are analyzed.

  3. Effect of steady versus oscillating flow on porcine coronary arterioles - Involvement of NO and superoxide anion

    NARCIS (Netherlands)

    Sorop, Oana; Spaan, Jos A. E.; Sweeney, Terrence E.; VanBavel, Ed

    2003-01-01

    Coronary blood vessels are compressed by the contracting myocardium. This leads to oscillations in flow in especially the subendocardium. We examined the effects of steady and oscillating flow on isolated, cannulated subendocardial and subepicardial porcine arterioles. Steady flow-induced dilation

  4. A predictive quasi-steady model of aerodynamic loads on flapping wings

    NARCIS (Netherlands)

    Wang, Q.; Goosen, J.F.L.; van Keulen, A.

    2016-01-01

    Quasi-steady aerodynamic models play an important role in evaluating aerodynamic performance and conducting design and optimization of flapping wings. The kinematics of flapping wings is generally a resultant motion of wing translation (yaw) and rotation (pitch and roll). Most quasi-steady models

  5. Steady-State Thermal-Hydraulics Analyses for the Conversion of the BR2 Reactor to LEU

    Energy Technology Data Exchange (ETDEWEB)

    Licht, J. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Bergeron, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Dionne, B. [Argonne National Lab. (ANL), Argonne, IL (United States); Van den Branden, G. [SCK CEN (Belgium); Kalcheva, S. [SCK CEN (Belgium); Sikik, E. [SCK CEN (Belgium); Koonen, E. [SCK CEN (Belgium)

    2015-12-01

    BR2 is a research reactor used for radioisotope production and materials testing. It’s a tank-in-pool type reactor cooled by light water and moderated by beryllium and light water (Figure 1). The reactor core consists of a beryllium moderator forming a matrix of 79 hexagonal prisms in a hyperboloid configuration; each having a central bore that can contain a variety of different components such as a fuel assembly, a control or regulating rod, an experimental device, or a beryllium or aluminum plug. Based on a series of tests, the BR2 operation is currently limited to a maximum allowable heat flux of 470 W/cm2 to ensure fuel plate integrity during steady-state operation and after a loss-of-flow/loss-of-pressure accident.

  6. Ankle torque steadiness is related to muscle activation variability and coactivation in children with cerebral palsy

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Rose, Martin Høyer; Sløk, Rikke

    2009-01-01

    The aims of this study were to: (1) investigate the significance of muscle activation variability and coactivation for the ability to perform steady submaximal ankle torque (torque steadiness) in healthy children and those with cerebral palsy (CP), and (2) assess ankle function during isometric...... contractions in those children. Fourteen children with CP who walked with equinus foot deformity and 14 healthy (control) children performed maximal and steady submaximal ankle dorsi- and plantarflexions. Dorsiflexion torque steadiness was related to agonist and antagonist muscle activation variability as well...... as the plantarflexor coactivation level in children with CP (r > 0.624, P torque and submaximal torque steadiness of both dorsi- and plantarflexion compared with controls (P muscle groups may benefit from strength training, as they exhibit...

  7. A steady-state target calculation method based on "point" model for integrating processes.

    Science.gov (United States)

    Pang, Qiang; Zou, Tao; Zhang, Yanyan; Cong, Qiumei

    2015-05-01

    Aiming to eliminate the influences of model uncertainty on the steady-state target calculation for integrating processes, this paper presented an optimization method based on "point" model and a method determining whether or not there is a feasible solution of steady-state target. The optimization method resolves the steady-state optimization problem of integrating processes under the framework of two-stage structure, which builds a simple "point" model for the steady-state prediction, and compensates the error between "point" model and real process in each sampling interval. Simulation results illustrate that the outputs of integrating variables can be restricted within the constraints, and the calculation errors between actual outputs and optimal set-points are small, which indicate that the steady-state prediction model can predict the future outputs of integrating variables accurately. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  8. The effect of steady aerodynamic loading on the flutter stability of turbomachinery blading

    Science.gov (United States)

    Smith, Todd E.; Kadambi, Jaikrishnan R.

    1991-01-01

    An aeroelastic analysis is presented which accounts for the effect of steady aerodynamic loading on the aeroelastic stability of a cascade of compressor blades. The aeroelastic model is a two degree of freedom model having bending and torsional displacements. A linearized unsteady potential flow theory is used to determine the unsteady aerodynamic response coefficients for the aeroelastic analysis. The steady aerodynamic loading was caused by the addition of airfoil thickness and camber and steady flow incidence. The importance of steady loading on the airfoil unsteady pressure distribution is demonstrated. Additionally, the effect of steady loading on the tuned flutter behavior and flutter boundaries indicates that neglecting either airfoil thickness, camber or incidence could result in nonconservative estimates of flutter behavior.

  9. Periodicity in magmatic systems

    Science.gov (United States)

    Caricchi, Luca

    2016-04-01

    Magmatic systems show periodicity in productivity, magma chemistry and dynamics of volcanic eruptions. The timescales over which such parameters change are highly variable and ranges between several tens of millions of years down to few hundredths of thousands years. While magmatic activity appears modulated at various frequencies, the lifetime of single volcanic systems, the duration of emplacement of single plutons, or the timespan over which a given volcanic region is active, appear to last for distinct but characteristic periods of time. Hundredths of thousands of years is a typical number for the range of zircon crystallisation ages in the products of large eruptions or for the lifetime of single plutons, while activity in volcanic regions or the duration of emplacement of crustal batholiths appears to last up to about 10 Ma. Several mechanisms such as variable magma productivity in the mantle, delamination, thermal and mechanical maturation of the crust have been proposed to modulate magmatic activity. All these processes indeed contribute to modulate the periodicity of magmatic activity, but because certain timescales are recurrent, some fundamental processes must play a fundamental role in regulating the "tempo" of magmatism. Are transitions of behaviour finally the product of major changes in mantle dynamics or is the crust the plays the pivotal role in modulating periodic variations observed in magmatic systems? In this contribution I will provide an overview of existing data on periodicity of magmatic systems and use thermal modelling to show that periodic variations of magma chemistry and the physical properties of magmas are an inexorable consequence of the evolution of the thermal budget of magmatic systems. I hope to trigger discussion and collaborations between experts of geodynamics and magmatism to establish relationships between periodicity, mantle and crustal processes.

  10. Investigations on Quasi-Steady Characteristics for an Airfoil Oscillating at Low Reduced Frequencies

    Directory of Open Access Journals (Sweden)

    Deepakkumar M. Sharma

    2010-01-01

    Full Text Available Wind tunnel experiments were conducted on NACA-0015 airfoil model to investigate the effect of the reduced frequency (κ=0.0001 to 0.5 and that Reynolds number (Re=0.2E06 to 0.7E06 on the aerodynamic characteristics and hysteresis behavior associated with the oscillating motion of the airfoil. Pressure measurements were conducted on the midspan of the airfoil for quantitative results. Although dynamic stall study has been conducted to greater extent of reduced frequencies, for current work, emphasis is made on investigating the low reduced frequency regimes up to which the steady conditions prevail under dynamic mode of operation. In present investigations of oscillating sinusoidal α=10∘+15∘sin(ωt motion, the airfoil was allowed to execute oscillating motion from static to almost steady (quasi-steady conditions with the incremental increase in the reduced frequency. The limiting conditions of κ and Re for quasi-steady state are carefully extracted and analyzed. Static and quasi-steady conditions are critically assessed in context of the existence of laminar separation bubble within the opted Re regime. The flow separation was found to be trailing edge flow separation with existence of LSB upstream towards the leading edge with no evidence of unsteady flow reversals. Normal force defect and pitch damping factor are estimated for varied range of Re and κ within the quasi-steady conditions. Re effect is dominant at steady and quasi-steady regimes while the effect of reduced frequency is negligible in this domain. Minor hysteresis effect associated with the stalling and reattachment point is due to existence of weak stall flutter which is further restrained by the oscillatory motion of the airfoil. Laminar separation bubble traced during steady condition is conserved in quasi-steady domain as well.

  11. Outsourcing and "dismantling" of steady jobs at hospitals.

    Science.gov (United States)

    Souza, Helton Saragor de; Mendes, Áquilas Nogueira

    2016-04-01

    To relate hospitals' organizational structure as the core of a web of outsourced services and flexible employment bonds among healthcare professionals in the context of finance capitalism, analyzing work arrangements based mainly on the type of employment bond. Qualitative research through ethnography, interviews, data analysis, and case studies. The case studies were concentrated in 3 hospitals located in the São Paulo metropolitan region under different management types: public administration; outsourced administration via a healthcare social organization (HSO); and private administration. This study highlights a trend in outsourcing, dismantling of steady jobs, and shaping working relations asymmetrically in terms of healthcare professions. These aspects are characteristic of contemporary capitalism and post-Fordist work organization. In this context, the state under sponsorship cripples the very existence of an effective human resources policy, creating a favorable environment for outsourcing and flexibility of employment bonds among healthcare workers. Relacionar a estrutura organizativa dos hospitais como núcleo de uma rede de serviços subcontratados e a flexibilização dos vínculos contratuais dos profissionais de saúde no contexto de capitalismo financeirizado, analisando os regimes de trabalho condicionados centralmente pelo vínculo empregatício. Pesquisa qualitativa através de etnografia, realização de entrevistas, análise de dados e utilização de estudo de caso. Os estudos de caso concentram-se em três hospitais localizados Região Metropolitana de São Paulo com gestões distintas: administração pública; administração terceirizada para Organização Social de Saúde (OSS); e administração privada. Destacamos a tendência da terceirização, do desmonte do emprego estável e a conformação de relações trabalhistas assimétricas para as profissões em saúde. Esses aspectos são característicos do período do capitalismo

  12. Specific determination of maximal lactate steady state in soccer players.

    Science.gov (United States)

    Loures, João P; Chamari, Karim; Ferreira, Eliel C; Campos, Eduardo Z; Zagatto, Alessandro M; Milioni, Fabio; da Silva, Adelino S R; Papoti, Marcelo

    2015-01-01

    The aim of this study was to establish the validity of the anaerobic threshold (AT) determined on the soccer-specific Hoff circuit (ATHoff) to predict the maximal lactate steady-state exercise intensity (MLSSHoff) with the ball. Sixteen soccer players (age: 16.0 ± 0.5 years; body mass: 63.7 ± 9.0 kg; and height: 169.4 ± 5.3 cm) were submitted to 5 progressive efforts (7.0-11.0 km·h) with ball dribbling. Thereafter, 11 players were submitted to 3 efforts of 30 minutes at 100, 105, and 110% of ATHoff. The ATHoff corresponded to the speed relative to 3.5 mmol·L lactate concentration. The speed relative to 4.0 mmol·L was assumed to be ATHoff4.0, and the ATHoffBI was determined through bisegmented adjustment. For comparisons, Student's t-test, intraclass correlation coefficient (ICC), and Bland and Altman analyses were used. For reproducibility, ICC, typical error, and coefficient of variation were used. No significant difference was found between AT test and retest determined using different methods. A positive correlation was observed between ATHoff and ATHoff4.0. The MLSSHoff (10.6 ± 1.3 km·h) was significantly different compared with ATHoff (10.2 ± 1.2 km·h) and ATHoffBI (9.5 ± 0.4 km·h) but did not show any difference from LAnHoff4.0 (10.7 ± 1.4 km·h). The MLSSHoff presented high ICCs with ATHoff and ATHoff4.0 (ICC = 0.94; and ICC = 0.89; p ≤ 0.05, respectively), without significant correlation with ATHoffBI. The results suggest that AT determined on the Hoff circuit is reproducible and capable of predicting MLSS. The ATHoff4.0 was the method that presented a better approximation to MLSS. Therefore, it is possible to assess submaximal physiological variables through a specific circuit performed with the ball in young soccer players.

  13. Hydraulic flow through a contraction: multiple steady states

    NARCIS (Netherlands)

    Akers, B.; Bokhove, Onno

    We consider shallow water flows through a channel with a contraction by experimental and theoretical means. The horizontal channel consists of a sluice gate and an upstream channel of constant width $b_0$ ending in a linear contraction of minimum width $b_c$. Experimentally, we observe upstream

  14. Hydraulic flow through a channel contraction: multiple steady states

    NARCIS (Netherlands)

    Akers, B.; Bokhove, Onno

    2008-01-01

    We have investigated shallow water flows through a channel with a contraction by experimental and theoretical means. The horizontal channel consists of a sluice gate and an upstream channel of constant width $b_0$ ending in a linear contraction of minimum width $b_c$. Experimentally, we observe

  15. Realizing Steady Supply to a Treatment Plant from Multiple Sources

    NARCIS (Netherlands)

    van Nooijen, R.R.P.; Kolechkina, A.G.

    2016-01-01

    In sewer systems sewage from different areas is often treated in a shared Waste Water Treatment Plant (WWTP). Currently the flows from different areas are usually determined by needs local to that area. During dry weather this may result in large variations in the flow into the WWTP. There are two

  16. Steady-state critical loads of acidity for forest soils in the Georgia Basin, British Columbia

    Directory of Open Access Journals (Sweden)

    Shaun A. WATMOUGH

    2010-08-01

    Full Text Available There has been growing interest in acid rain research in western Canada where sulphur (S and nitrogen (N emissions are expected to increase during the next two decades. One region of concern is southern British Columbia, specifically the Georgia Basin, where emissions are expected to increase owing to the expansion of industry and urban centres (Vancouver and Victoria. In the current study, weathering rates and critical loads of acidity (S and N for forest soils were estimated at nineteen sites located within the Georgia Basin. A base cation to aluminium ratio of 10 was selected as the critical chemical criterion associated with ecosystem damage. The majority of the sites (58% had low base cation weathering rates (≤50 meq m–2 y–1 based on the PROFILE model. Accordingly, mean critical load for the study sites, estimated using the steady-state mass balance model, ranged between 129–168 meq m–2 y–1. Annual average total (wet and dry S and N deposition during the period 2005–2006 (estimated by the Community Multiscale Air Quality model, exceeded critical load at five–nine of the study sites (mean exceedance = 32–46 meq m–2 y–1. The high-elevation (>1000 m study sites had shallow, acid sensitive, soils with low weathering rates; however, critical loads were predominantly exceeded at sites close to Vancouver under higher modelled deposition loads. The extent of exceedance is similar to other industrial regions in western and eastern Canada.

  17. Diversification Models of Sales Activity for Steady Development of an Enterprise

    Directory of Open Access Journals (Sweden)

    Nestor Shpak

    2016-04-01

    Full Text Available The paper substantiates the importance of the optimal directionality choice of sales activity as one of the main lines of enterprise activity, the functioning of which should be complete, synchronous and complementary. Diversification is one of the powerful instruments to ensure the steady development of the sales activity of an enterprise. Three models of sales activity diversification of an enterprise are developed. The first model is based on unveiling the potential of sales channels and allows us to show the peculiarities of their use. The second model of the optimal quantitative distribution of production between sales channels is based on profit maximization. This approach not only takes into account the evaluation of the prescribed parameters of sales channels, but also provides the high profitability of each assortment item and of the whole enterprise. The third model of the optimal distribution of production between sales channels accounts for the experience of collaboration between the enterprise and sales channels during the past period and ensures the minimal risk and appropriate profitability for each sales channel. The proposed models are tested and compared to actual data of the enterprise; the advantages and peculiarities of each model are discussed.

  18. Algebraic method for constructing singular steady solitary waves: A case study

    CERN Document Server

    Clamond, Didier; Galligo, André

    2016-01-01

    This article describes the use of algebraic methods in a phase plane analysis of ordinary differential equations. The method is illustrated by the study of capillary-gravity steady surface waves propagating in shallow water. We consider the (fully nonlinear, weakly dispersive) Serre-Green-Naghdi equations with surface tension, because it provides a tractable model that, in the same time, is not too simple so the interest of the method can be emphasised. In particular, we analyse a special class of solutions, the solitary waves, which play an important role in many fields of Physics. In capillary-gravity regime, there are two kinds of localised infinitely smooth travelling wave solutions -- solitary waves of elevation and of depression. However, if we allow the solitary waves to have an angular point, the "zoology" of solutions becomes much richer and the main goal of this study is to provide a complete classification of such singular localised solutions using the methods of the effective Algebraic Geometry.

  19. Steady Flow in Subject-Specific Human Airways from Mouth to Sixth Bronchial Generation

    Science.gov (United States)

    Banko, Andrew; Coletti, Filippo; Schiavazzi, Daniele; Elkins, Christopher; Eaton, John

    2013-11-01

    Understanding the complex flow topology within the human lung is critical to assess gas exchange and particle transport as they relate to the development and treatment of respiratory diseases. While idealized airway models have been investigated extensively, only limited information is available for anatomically accurate geometries. We have measured the full three-dimensional, mean velocity field from the mouth to the sixth bronchial generation in a patient-specific geometry at steady inspiration. Magnetic resonance velocimetry is used to measure the flow of water at realistic Reynolds number in a 3D-printed model derived from the CT scan of a healthy subject. The canonical laryngeal jet is observed; however, its structure is altered by an upstream jet behind the tongue, which is not discussed in the literature. Regions of separation in the supraglottic space are found to generate streamwise vortices. The resulting swirl persists to the first bifurcation and modifies the vorticity distribution in the main bronchi relative to that of a symmetric bifurcation with uniform inlet conditions. An integral momentum distortion parameter is calculated along several complete bronchial paths to assess the impact of branching angle and generation length on the flow field.

  20. FRAPCON-1: a computer code for the steady state analysis of oxide fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Berna, G. A.; Bohn, M. P.; Coleman, D. R.; Lanning, D. D.

    1978-08-01

    FRAPCON is a FORTRAN IV computer code which predicts the steady state long-term burnup response of a light water reactor fuel rod. The coupled effects of fuel and cladding deformation, temperature, and internal gas pressure on the behavior of the fuel rod are considered in determining fuel rod response. The cladding deformation model includes multi-axial, elasto-plastic analysis and considers both primary and secondary creep. The fuel temperature model considers the effects of fuel cracking and relocation in determining the fuel temperature distribution. Burnup dependent fission gas generation and release is included in calculating fuel rod internal pressure. An integral fuel rod failure subcode determines failure and failure modes based on the operating conditions at each timestep. The material property subcode, MATPRO, provides gas, fuel and cladding properties to the computational subcodes in FRAPCON. No material properties need to be supplied by the code user. FRAPCON is a completely modular code with each major computational subcode isolated within the code and coupled to the main code by subroutine calls and data transfer through argument lists. FRAPCON is soft-coupled to the transient fuel rod code, FRAP-T, to provide initial conditions to initiate analysis of such off-normal transients as a loss-of-coolant accident. The code is presently programmed and running on a CDC 7600 computer.

  1. Experiments on a Steady Low Reynolds Number Airfoil in a Shear Flow

    Science.gov (United States)

    Olson, David; Naguib, Ahmed; Koochesfahani, Manoochehr

    2016-11-01

    The aerodynamics of steady airfoils in uniform flow have received considerably more attention than that of an airfoil operating in a non-uniform flow. Inviscid theory by Tsien (1943) shows that an airfoil experiences a decrease in the zero lift angle of attack for a shear flow with uniform clockwise vorticity. The current work utilizes a shaped honeycomb technique to create a velocity profile with a large region of uniform shear in a water tunnel. Direct force measurements are implemented and validated using experiments on a circular cylinder and NACA 0012 in a uniform cross-flow. Results for a NACA 0012 airfoil with a chord Reynolds number of 1.2 ×104 in a non-uniform approach flow are compared to concurrent CFD calculations (presented in a companion talk) showing an increase in the zero lift angle of attack; in contradiction with inviscid theory. The effect of shear on the mean lift coefficient over a wide range of angles of attack is also explored. This work was supported by AFOSR Award Number FA9550-15-1-0224.

  2. Hydrodynamics of steady state phloem transport with radial leakage of solute

    Science.gov (United States)

    Cabrita, Paulo; Thorpe, Michael; Huber, Gregor

    2013-01-01

    Long-distance phloem transport occurs under a pressure gradient generated by the osmotic exchange of water associated with solute exchange in source and sink regions. But these exchanges also occur along the pathway, and yet their physiological role has almost been ignored in mathematical models of phloem transport. Here we present a steady state model for transport phloem which allows solute leakage, based on the Navier-Stokes and convection-diffusion equations which describe fluid motion rigorously. Sieve tube membrane permeability Ps for passive solute exchange (and correspondingly, membrane reflection coefficient) influenced model results strongly, and had to lie in the bottom range of the values reported for plant cells for the results to be realistic. This smaller permeability reflects the efficient specialization of sieve tube elements, minimizing any diffusive solute loss favored by the large concentration difference across the sieve tube membrane. We also found there can be a specific reflection coefficient for which pressure profiles and sap velocities can both be similar to those predicted by the Hagen-Poiseuille equation for a completely impermeable tube. PMID:24409189

  3. Numerical study of the air-flow in an oscillating water column wave energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Paixao Conde, J.M. [Department of Mechanical and Industrial Engineering, Faculty of Sciences and Technology, New University of Lisbon, Monte de Caparica, 2829-516 Caparica (Portugal); IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal); Gato, L.M.C. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal)

    2008-12-15

    The paper presents a numerical study of the air-flow in a typical pneumatic chamber geometry of an oscillating water column (OWC)-type wave energy converter (WEC), equipped with two vertical-axis air turbines, asymmetrically placed on the top of the chamber. Outwards and inwards, steady and periodic, air-flow calculations were performed to investigate the flow distribution at the turbines' inlet sections, as well as the properties of the air-jet impinging on the water free-surface. The original design of the OWC chamber is likely to be harmful for the operation of the turbines due to the possible air-jet-produced water-spray at the water free-surface subsequently ingested by the turbine. A geometry modification of the air chamber, using a horizontal baffle-plate to deflect the air from the turbines, is proposed and proved to be very effective in reducing the risk of water-spray production from the inwards flow. The flow distribution at the turbines' inlet sections for the outwards flow was found to be fairly uniform for the geometries considered, providing good inlet flow conditions for the turbines. Steady flow was found to be an acceptable model to study the air-flow inside the pneumatic chamber of an OWC-WEC. (author)

  4. "Ictal" lateralized periodic discharges.

    Science.gov (United States)

    Sen-Gupta, Indranil; Schuele, Stephan U; Macken, Micheal P; Kwasny, Mary J; Gerard, Elizabeth E

    2014-07-01

    Whether lateralized periodic discharges (LPDs) represent ictal or interictal phenomena, and even the circumstances in which they may represent one or the other, remains highly controversial. Lateralized periodic discharges are, however, widely accepted as being ictal when they are time-locked to clinically apparent symptoms. We sought to investigate the characteristics of "ictal" lateralized periodic discharges (ILPDs) defined by time-locked clinical symptoms in order to explore the utility of using this definition to dichotomize LPDs into "ictal" and "nonictal" categories. Our archive of all continuous EEG (cEEG) reports of adult inpatients undergoing prolonged EEG monitoring for nonelective indications between 2007 and 2011 was searched to identify all reports describing LPDs. Lateralized periodic discharges were considered ILPDs when they were reported as being consistently time-locked to clinical symptoms; LPDs lacking a clear time-locked correlate were considered to be "nonictal" lateralized periodic discharges (NILPDs). Patient charts and available neuroimaging studies were also reviewed. Neurophysiologic localization of LPDs, imaging findings, presence of seizures, discharge outcomes, and other demographic factors were compared between patients with ILPDs and those with NILPDs. p-Values were adjusted for false discovery rate (FDR). One thousand four hundred fifty-two patients underwent cEEG monitoring at our institution between 2007 and 2011. Lateralized periodic discharges were reported in 90 patients, 10 of whom met criteria for ILPDs. Nine of the patients with ILPDs demonstrated motor symptoms, and the remaining patient experienced stereotyped sensory symptoms. Ictal lateralized periodic discharges had significantly increased odds for involving central head regions (odds ratio [OR]=11; 95% confidence interval [CI]=2.16-62.6; p=0.018, FDR adjusted), with a trend towards higher proportion of lesions involving the primary sensorimotor cortex (p=0.09, FDR

  5. Distinct features of auditory steady-state responses as compared to transient event-related potentials.

    Directory of Open Access Journals (Sweden)

    Li Zhang

    Full Text Available Transient event-related potentials (ERPs and steady-state responses (SSRs have been popularly employed to investigate the function of the human brain, but their relationship still remains a matter of debate. Some researchers believed that SSRs could be explained by the linear summation of successive transient ERPs (superposition hypothesis, while others believed that SSRs were the result of the entrainment of a neural rhythm driven by the periodic repetition of a sensory stimulus (oscillatory entrainment hypothesis. In the present study, taking auditory modality as an example, we aimed to clarify the distinct features of SSRs, evoked by the 40-Hz and 60-Hz periodic auditory stimulation, as compared to transient ERPs, evoked by a single click. We observed that (1 SSRs were mainly generated by phase synchronization, while late latency responses (LLRs in transient ERPs were mainly generated by power enhancement; (2 scalp topographies of LLRs in transient ERPs were markedly different from those of SSRs; (3 the powers of both 40-Hz and 60-Hz SSRs were significantly correlated, while they were not significantly correlated with the N1 power in transient ERPs; (4 whereas SSRs were dominantly modulated by stimulus intensity, middle latency responses (MLRs were not significantly modulated by both stimulus intensity and subjective loudness judgment, and LLRs were significantly modulated by subjective loudness judgment even within the same stimulus intensity. All these findings indicated that high-frequency SSRs were different from both MLRs and LLRs in transient ERPs, thus supporting the possibility of oscillatory entrainment hypothesis to the generation of SSRs. Therefore, SSRs could be used to explore distinct neural responses as compared to transient ERPs, and help us reveal novel and reliable neural mechanisms of the human brain.

  6. The Preliminary GAMMA Code Thermal hydraulic Analysis for the Steady State of HTR-10 Initial Core

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Ji Su; Lim, Hong Sik; Lee, Won Jae

    2006-07-15

    This report describes the preliminary thermalhydraulic analysis of HTR-10 steady state full power initial core to provide a benchmark calculation of VHTGR(Very High-Temperature Gas-Cooled Reactors) safety analysis code of GAMMA(GAs Multicomponent Mixture Analysis). The input data of GAMMA code are produced for the models of fluid block, wall block, radiation heat transfer and each component material properties in HTR-10 reactor. The temperature and flow distributions of HTR-10 steady state 10 MW{sub th} full power initial core are calculated by GAMMA code with boundary conditions of total reactor inlet flow rate of 4.32 kg/s, inlet temperature of 250 .deg. C, inlet pressure of 3 MPa, outlet pressure of 2.992 MPa and the fixed temperature at RCCS water cooling tube of 50 .deg C. The calculation results are compared with the measured solid material temperatures at 22 fixed instrumentation positions in HTR-10. The wall temperature distribution in pebble bed core shows that the minimum temperature of 358 .deg. C is located at upper core, a higher temperature zone than 829 .deg. C is located at the inner region of 0.45 m radius at the bottom of core centre, and the maximum wall temperature is 897 .deg. C. The wall temperatures linearly decreases at radially and axially farther side from the bottom of core centre. The maximum temperature of RPV is 230 .deg. C, and the maximum values of fuel average temperature and TRISO centreline temperature are 907 .deg. C and 929 .deg. C, respectively and they are much lower than the fuel temperature limitation of 1230 .deg. C. The comparsion between the GAMMA code predictions and the measured temperature data shows that the calculation results are very close to the measured values in top and side reflector region, but a great difference is appeared in bottom reflector region. Some measured data are abnormally high in bottom reflector region, and so the confirmation of data is necessary in future. Fifteen of twenty two data have a

  7. Technical Note: Clinical translation of the Rapid-Steady-State-T1 MRI method for direct cerebral blood volume quantification.

    Science.gov (United States)

    Perles-Barbacaru, Teodora-Adriana; Tropres, Irene; Sarraf, Michel G; Chechin, David; Zaccaria, Affif; Grand, Sylvie; Le Bas, Jean-François; Berger, François; Lahrech, Hana

    2015-11-01

    In preclinical studies, the Rapid-Steady-State-T1 (RSST1) MRI method has advantages over conventional MRI methods for blood volume fraction (BVf) mapping, since after contrast agent administration, the BVf is directly quantifiable from the signal amplitude corresponding to the vascular equilibrium magnetization. This study focuses on its clinical implementation and feasibility. Following sequence implementation on clinical Philips Achieva scanners, the RSST1-method is assessed at 1.5 and 3 T in the follow-up examination of neurooncological patients receiving 0.1-0.2 mmol/kg Gd-DOTA to determine the threshold dose needed for cerebral BVf quantification. Confounding effects on BVf quantification such as transendothelial water exchange, transverse relaxation, and contrast agent extravasation are evaluated. For a dose≥0.13 mmol/kg at 1.5 T and ≥0.16 mmol/kg at 3 T, the RSST1-signal time course in macrovessels and brain tissue with Gd-DOTA impermeable vasculature reaches a steady state at maximum amplitude for about 8 s. In macrovessels, a BVf of 100% was obtained validating cerebral microvascular BVf quantification (3.5%-4.5% in gray matter and 1.5%-2.0% in white matter). In tumor tissue, a continuously increasing signal is detected, necessitating signal modeling for tumor BVf calculation. Using approved doses of Gd-DOTA, the steady state RSST1-signal in brain tissue is reached during the first pass and corresponds to the BVf. The first-pass duration is sufficient to allow accurate BVf quantification. The RSST1-method is appropriate for serial clinical studies since it allows fast and straightforward BVf quantification without arterial input function determination. This quantitative MRI method is particularly useful to assess the efficacy of antiangiogenic agents.

  8. Emergence of steady and oscillatory localized structures in a phytoplankton-nutrient model

    Science.gov (United States)

    Zagaris, A.; Doelman, A.

    2011-12-01

    Co-limitation of marine phytoplankton growth by light and nutrient, both of which are essential for phytoplankton, leads to complex dynamic behaviour and a wide array of coherent patterns. The building blocks of this array can be considered to be deep chlorophyll maxima, or DCMs, which are structures localized in a finite depth interior to the water column. From an ecological point of view, DCMs are evocative of a balance between the inflow of light from the water surface and of nutrients from the sediment. From a (linear) bifurcational point of view, they appear through a transcritical bifurcation in which the trivial, no-plankton steady state is destabilized. This paper is devoted to the analytic investigation of the weakly nonlinear dynamics of these DCM patterns, and it has two overarching themes. The first of these concerns the fate of the destabilizing stationary DCM mode beyond the centre manifold regime. Exploiting the natural singularly perturbed nature of the model, we derive an explicit reduced model of asymptotically high dimension which fully captures these dynamics. Our subsequent and fully detailed study of this model—which involves a subtle asymptotic analysis necessarily transgressing the boundaries of a local centre manifold reduction—establishes that a stable DCM pattern indeed appears from a transcritical bifurcation. However, we also deduce that asymptotically close to the original destabilization, the DCM loses its stability in a secondary bifurcation of Hopf type. This is in agreement with indications from numerical simulations available in the literature. Employing the same methods, we also identify a much larger DCM pattern. The development of the method underpinning this work—which, we expect, shall prove useful for a larger class of models—forms the second theme of this paper.

  9. Modeling hourly subsurface drainage using steady-state and transient methods

    Science.gov (United States)

    Xian, Changchi; Qi, Zhiming; Tan, Chin S.; Zhang, Tie-Quan

    2017-07-01

    Computer models have been frequently used to simulate the hydrologic and environmental processes in subsurface-drained cropland. The widely-tested steady-state Hooghoudt (ssH) equation, implemented in the Root Zone Water Quality Model (RZWQM2, version 2.94.00), serves in simulating subsurface drainage. However, transient methods such as the integrated Hooghoudt (inH) and van Schilfgaarde (vanS) equations have seldom been implemented in models. In the present study, RZWQM2's hydrologic component was modified to initiate the soil water redistribution process when rainfall occurred. The three drainage equations (ssH, inH and vanS) were tested in each of two versions of RZWQM2 (original and modified). Field data from Iowa (2007-2008) and Ontario (2009-2010) were used to evaluate different model version × equation combinations' simulation accuracy at both daily and hourly scales, evaluated using the percent of bias (PBIAS), Nash-Sutcliffe efficiency coefficient (NSE), and the Index of Agreement (IoA). On a daily scale and across equations, for the Iowa data the original model (PBIAS ⩽ 14.96, NSE ⩾ 0.40, ⩾ 0.69) was outperformed by the modified model (PBIAS ⩽ 6.48, NSE ⩾ 0.70, IoA ⩾ 0.76). Similarly, for the Ontario data, the original model (PBIAS ⩽ 8.87, NSE ⩾ 0.19, IoA ⩾ 0.65) was outperformed by the modified model (PBIAS ⩽ 3.59, NSE ⩾ 0.31, IoA ⩾ 0.67). However, based on a parity of PBIAS, NSE and IoA values, hourly scale tile drainage computed using the modified model equipped with transient equations did not improve model performance compared with the original ssH equation.

  10. Periodic Table of Students.

    Science.gov (United States)

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  11. Hereditary periodic fever syndromes

    NARCIS (Netherlands)

    McDermott, MF; Frenkel, J

    Hereditary periodic fever syndromes are defined by recurrent attacks of generalised inflammation for which no infectious or auto-immune cause can be identified. For most of these disorders, the molecular basis has recently been elucidated. This has opened the prospect of novel therapeutic

  12. Sawtooth Period Scaling

    CERN Document Server

    Connor, J W; Hastie, R J; Zocco, A

    2012-01-01

    We discuss the role of neoclassical resistivity and local magnetic shear in the prediction of the sawtooth period in tokamaks. When collisional detrapping of electrons is considered the value of the safety factor on axis, $q(t,0)$, evolves on a new time scale, $\\tau_{*}=\\tau_{\\eta}\

  13. Effects of Energy Beverage Consumption on Pistol Aiming Steadiness in Law Enforcement Officers.

    Science.gov (United States)

    Monaghan, Taylor P; Jacobson, Bert H; Sellers, John H; Estrada, Carlos A

    2017-09-01

    Monaghan, TP, Jacobson, BH, Sellers, JH, and Estrada, CA. Effects of energy beverage consumption on pistol aiming steadiness in law enforcement officers. J Strength Cond Res 31(9): 2557-2561, 2017-The popularity of energy drinks (EDs)/shots (ESs) has grown steadily over the years resulting in billions of dollars of sales annually. Energy drink marketing focuses on the improved performance and alertness and a reduction in fatigue. Although caffeine comprises one of the ingredients, it is not fully known how the combination of the many remaining active ingredients affects physical performance. The purpose of this study was to investigate the effect of a commercially available ES on pistol aiming steadiness. Subjects (N = 10) consisted of accredited police officers in the Midwest. A randomized, blinded, crossover design was used to evaluate the pistol aiming steadiness after the consumption of an ES or placebo. Pistol aiming steadiness was measured using a hole/stylus steadiness tester and laser attached to a training pistol before and 30 minutes after ES or placebo consumption. Analysis revealed that the ES significantly (p ≤ 0.05) impaired pistol steadiness, whereas the placebo yielded no significant difference in aiming steadiness. Based on these results, it was concluded that the consumption of an ES could compromise aiming accuracy and shot placement, thereby jeopardizing the health and welfare of law enforcement personnel.

  14. The effects of ionic strength on the toxicity of aluminium to Atlantic salmon (Salmo salar under non-steady state chemical conditions

    Directory of Open Access Journals (Sweden)

    Antonio B.S. POLÉO

    2002-02-01

    Full Text Available We have tested the influence of water ionic strength on the toxicity of aluminium in fish by comparing the mortality of Atlantic salmon (Salmo salar parr exposed to Al-rich water with additions of Ca2+ or Na+. The fish were exposed in parallel to Al-rich water (Al 500 μg l-1, pH 5.8 under non-steady state conditions, with and without the addition of one of the two base cations. The amount of Na+ and Ca2+ added to the water was calculated in order to obtain an identical increase in water ionic strength. Fish mortality was dependent on water residence time and whether or not base cations were added to the Al-rich water. In all Al-exposures, the highest mortality was always observed in fish exposed to water with the shortest residence time. Mortality decreased systematically with increasing water residence time through the exposure set-up. The addition of a base cation, Ca2+ or Na+, to the Al-rich water reduced fish mortality significantly compared to the Al-only exposures. Furthermore, increasing ionic strength with Na+ reduced mortality to a larger extent than the corresponding increase in ionic strength by the addition of Ca2+. The variation in mortality between the various aluminium and base cation treatments is discussed in terms of aluminium chemistry, specific mitigating effects of Ca2+ and Na+, and the general importance of water ionic strength. This study clearly demonstrates that Ca2+ does not play an unique role as an ameliorating cation for Al-toxicity in fish under non-steady state chemical conditions. Thus, ionic strength seems to be important, probably for the interaction between aluminium and the gill surface, reducing the possibility for positively charged aluminium species to bind to negatively charged sites.

  15. Transversally periodic solitary gravity–capillary waves

    Science.gov (United States)

    Milewski, Paul A.; Wang, Zhan

    2014-01-01

    When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity–capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity–capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922

  16. Two-phase bioconversion product recovery by microfiltration I. Steady state studies.

    Science.gov (United States)

    Conrad, P B; Lee, S S

    1998-03-20

    Recovery of an aqueous bioconversion product from complex, two-phase Pseudomonas putida broths containing 20% (v/v) soybean oil presents a significant challenge for downstream processing. Although not used before in multiple-phase separation for complex biotech products, crossflow filtration employing ceramic filters is one of the most attractive options which allow the design of integrated, continuous bioconversion processes. As a first attempt, we studied multichannel, monolithic ceramic membranes of different nominal pore sizes and lumen diameters under steady-state conditions. The best performance was obtained with 0.2-microm-pore/3-mm-lumen membrane, which completely rejected both cells and oil droplets from the permeate, creating a clear aqueous product stream. Although the same separation was achieved, the 50K molecular weight cut-off (MWCO) ultrafilter showed greater irreversible but similar reversible resistance, in addition to an order-of-magnitude higher membrane resistance. Larger nominal pore microfilters, such as 0.45 and 1.0 microm, experienced both cell and oil leakage even at low transmembrane pressure (10 psig). Attributed to greater shear at the same recirculation rate, smaller lumen filters did provide greater permeate flux. However, for practical purposes, the 0. 2-microm-pore/4-mm-lumen ceramic membrane was chosen for further evaluation. Transmembrane pressures up to 50 psig provided only marginal gains in filtration performance, whereas increasing shear rate resulted in linear increases in steady-state flux, presumably due to formation of shear-sensitive, complex gel/oil/cell layer near the membrane surface. A nominal shear rate of 9200 s-1 and 20 psig transmembrane pressure were chosen as optimal operating conditions. Additional studies in a clean system revealed that as low as 5% (v/v) soybean oil in deionized (DI) water resulted in an order-of-magnitude decline in steady-state permeate flux. Breakthrough of oil droplets occurred at 35 psig

  17. Steady-state chlorophyll fluorescence (Fs) as a tool to monitor plant heat and drought stress

    Science.gov (United States)

    Cendrero Mateo, M.; Carmo-Silva, A.; Salvucci, M.; Moran, S. M.; Hernandez, M.

    2012-12-01

    Crop yield decreases when photosynthesis is limited by heat or drought conditions. Yet farmers do not monitor crop photosynthesis because it is difficult to measure at the field scale in real time. Steady-state chlorophyll fluorescence (Fs) can be used at the field level as an indirect measure of photosynthetic activity in both healthy and physiologically-perturbed vegetation. In addition, Fs can be measured by satellite-based sensors on a regular basis over large agricultural regions. In this study, plants of Camelina sativa grown under controlled conditions were subjected to heat and drought stress. Gas exchange and Fs were measured simultaneously with a portable photosynthesis system under light limiting and saturating conditions. Results showed that Fs was directly correlated with net CO2 assimilation (A) and inversely correlated with non-photochemical quenching (NPQ). Analysis of the relationship between Fs and Photosynthetically Active Radiation (PAR) revealed significant differences between control and stressed plants that could be used to track the status, resilience, and recovery of photochemical processes. In summary, the results provide evidence that Fs measurements, even without normalization, are an easy means to monitor changes in plant photosynthesis, and therefore, provide a rapid assessment of plant stress to guide farmers in resource applications. Figure1. Net CO2 assimilation rate (A) of Camelina sativa plants under control conditions and after heat stress exposure for 1 or 3 days (1d-HS and 3d-HS, respectively) (right) and control, drought and re-watering conditions (left). Conditions for infra-red gas analysis were: reference CO2 = 380 μmol mol-1, PPFD = 500 μmol m-2 s-1 and Tleaf set to 25°C (control, drought and re-water) or 35°C (HS). Different letters denote significant differences at the α=0.05 level. Values are means±SEM (n=10). Figure 2. Stable chlorophyll fluorescence (Fs) of Camelina sativa plants under control conditions and

  18. Interleaved silent steady state (ISSS) imaging: a new sparse imaging method applied to auditory fMRI.

    Science.gov (United States)

    Schwarzbauer, Christian; Davis, Matt H; Rodd, Jennifer M; Johnsrude, Ingrid

    2006-02-01

    The acoustic scanner noise that is generated by rapid gradient switching in echo planar imaging (EPI) is an important confounding factor in auditory fMRI. "Sparse imaging" designs overcome the influence of scanner noise on stimulus presentation by acquiring single brain volumes following a silent stimulus presentation period. However, conventional sparse imaging requires assumptions about the time-to-peak of the evoked hemodynamic response and reduces the amount of EPI data which can be acquired and hence statistical power. In this article, we describe an "interleaved silent steady state" (ISSS) sampling scheme in which we rapidly acquire a set of EPI volumes following each silent stimulus presentation period. We avoid T1-related signal decay during the acquisition of the EPI volumes by maintaining the steady state longitudinal magnetization with a train of silent slice-selective excitation pulses during the silent period, ensuring that signal contrast is constant across successive scans. A validation study comparing ISSS to conventional sparse imaging demonstrates that ISSS imaging provides time course information that is absent in conventional sparse imaging data. The ISSS sequence has a temporal resolution like event-related (ER) imaging within a single trial (unlike conventional sparse imaging, where ER-like temporal resolution can only be achieved by compiling data across many jittered trials of the same stimulus type). This temporal resolution within trials makes ISSS particularly suitable for experiments in which a) scanner noise would interfere with the perception and processing of the stimulus; b) stimuli are several seconds in duration, and activation is expected to evolve and change as the stimulus unfolds; and c) it is impractical to present a single stimulus more than once (for example, repetition priming or familiarity effects would be expected).

  19. Strain-rate dependence of the effective viscosity under steady-wave shock compression

    Energy Technology Data Exchange (ETDEWEB)

    Grady, D.E.

    1981-05-15

    Relationships among Hugoniot pressure, effective viscosity, and strain rate under conditions of steady-wave shock compression are predicted based on the assumption of invariance of a shock property equal to the product of the energy dissipated in shock compression and the rise time of the steady wave. Effective viscosity is found to decrease as happrox.e/sup -1/2/, while strain rate increases as eapprox.p/sup 4//sub h/ with Hugoniot pressure. These results are consistent with steady-wave profile measurements on aluminum.

  20. Relaxation, multiplicity of steady states, and autooscillations in kinetics of catalytic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kol`tsov, N.I.; Fedotov, V.Kh.; Alekseev, B.V. [Chuvash State Univ., Chuvashia (Russian Federation)

    1995-01-01

    A review of the authors` recent findings of researche into steady-state and non-steady-state catalytic reactions is given. The method for the estimation of relaxation times for particular reaction classes is generalized. Basic critical phenomena, such as the multiplicity of steady states, are discussed in terms of the structures of reaction schemes. Mechanisms of simplest catalytic oscillators are systematized. The results outlined in this paper are shown to reflect close relations between relaxation characteristics and complex critical phenomena, which are peculiar to catalytic reactions. The discussion is held within the framework of the mass action law.