Cell chip temperature measurements in different operation regimes of HCPV modules

NASA Astrophysics Data System (ADS)

Rumyantsev, V. D.; Chekalin, A. V.; Davidyuk, N. Yu.; Malevskiy, D. A.; Pokrovskiy, P. V.; Sadchikov, N. A.; Pan'chak, A. N.

2013-09-01

A new method has been developed for accurate measurements of the solar cell temperature in maximum power point (MPP) operation regime in comparison with that in open circuit (OC) regime (TMPP and TOC). For this, an electronic circuit has been elaborated for fast variation of the cell load conditions and for voltage measurements, so that VOC values could serve as an indicator of TMPP at the first moment after the load disconnection. The method was verified in indoor investigations of the single-junction AlGaAs/GaAs cells under CW laser irradiation, where different modifications of the heat spreaders were involved. PV modules of the "SMALFOC" design (Small-size concentrators; Multijunction cells; "All-glass" structure; Lamination technology; Fresnel Optics for Concentration) with triple-junction InGaP/GaAs/Ge cells were examined outdoors to evaluate temperature regimes of their operation.

The quiescent H-mode regime for high performance edge localized mode-stable operation in future burning plasmas [The quiescent H-mode regime for high performance ELM-stable operation in future burning plasmas

DOE PAGES

Garofalo, Andrea M.; Burrell, Keith H.; Eldon, David; ...

2015-05-26

For the first time, DIII-D experiments have achieved stationary quiescent H-mode (QH-mode) operation for many energy confinement times at simultaneous ITER-relevant values of beta, confinement, and safety factor, in an ITER similar shape. QH-mode provides excellent energy confinement, even at very low plasma rotation, while operating without edge localized modes (ELMs) and with strong impurity transport via the benign edge harmonic oscillation (EHO). By tailoring the plasma shape to improve the edge stability, the QH-mode operating space has also been extended to densities exceeding 80% of the Greenwald limit, overcoming the long-standing low-density limit of QH-mode operation. In the theory,more » the density range over which the plasma encounters the kink-peeling boundary widens as the plasma cross-section shaping is increased, thus increasing the QH-mode density threshold. Here, the DIII-D results are in excellent agreement with these predictions, and nonlinear MHD analysis of reconstructed QH-mode equilibria shows unstable low n kink-peeling modes growing to a saturated level, consistent with the theoretical picture of the EHO. Furthermore, high density operation in the QH-mode regime has opened a path to a new, previously predicted region of parameter space, named “Super H-mode” because it is characterized by very high pedestals that can be more than a factor of two above the peeling-ballooning stability limit for similar ELMing H-mode discharges at the same density.« less

Improving the accuracy of operation coding in surgical discharge summaries

PubMed Central

Martinou, Eirini; Shouls, Genevieve; Betambeau, Nadine

2014-01-01

Procedural coding in surgical discharge summaries is extremely important; as well as communicating to healthcare staff which procedures have been performed, it also provides information that is used by the hospital's coding department. The OPCS code (Office of Population, Censuses and Surveys Classification of Surgical Operations and Procedures) is used to generate the tariff that allows the hospital to be reimbursed for the procedure. We felt that the OPCS coding on discharge summaries was often incorrect within our breast and endocrine surgery department. A baseline measurement over two months demonstrated that 32% of operations had been incorrectly coded, resulting in an incorrect tariff being applied and an estimated loss to the Trust of £17,000. We developed a simple but specific OPCS coding table in collaboration with the clinical coding team and breast surgeons that summarised all operations performed within our department. This table was disseminated across the team, specifically to the junior doctors who most frequently complete the discharge summaries. Re-audit showed 100% of operations were accurately coded, demonstrating the effectiveness of the coding table. We suggest that specifically designed coding tables be introduced across each surgical department to ensure accurate OPCS codes are used to produce better quality surgical discharge summaries and to ensure correct reimbursement to the Trust. PMID:26734286

Vibration analysis of a hydro generator for different operating regimes

NASA Astrophysics Data System (ADS)

Haţiegan, C.; Pădureanu, I.; Jurcu, M.; Nedeloni, M. D.; Hamat, C. O.; Chioncel, C. P.; Trocaru, S.; Vasile, O.; Bădescu, O.; Micliuc, D.; (Filip Nedeloni, L.; Băra, A.; (Barboni Haţiegan, L.

2017-01-01

Based on experimental measurements, this paper presents the vibration analysis of a hydro generator that equips a Kaplan hydraulic turbine of a Hydropower plant in Romania. This analysis means vibrations measurement to different operating regimes of the hydro generator respectively before installing it and into operation, namely putting off load mode (unexcited and excited) respectively putting on load mode. By comparing, through the experimental results obtained before and after the operation of hydro aggregates are observed vibrations improvements.

Magnetic dipole discharges. II. Cathode and anode spot discharges and probe diagnostics

NASA Astrophysics Data System (ADS)

Stenzel, R. L.; Urrutia, J. M.; Ionita, C.; Schrittwieser, R.

2013-08-01

The high current regime of a magnetron-type discharge has been investigated. The discharge uses a permanent magnet as a cold cathode which emits secondary electrons while the chamber wall or a grounded electrode serves as the anode. As the discharge voltage is increased, the magnet develops cathode spots, which are short duration arcs that provide copious electrons to increase the discharge current dramatically. Short (1 μs), high current (200 A) and high voltage (750 V) discharge pulses are produced in a relaxation instability between the plasma and a charging capacitor. Spots are also observed on a negatively biased plane Langmuir probe. The probe current pulses are as large as those on the magnet, implying that the high discharge current does not depend on the cathode surface area but on the properties of the spots. The fast current pulses produce large inductive voltages, which can reverse the electrical polarity of the magnet and temporarily operate it as an anode. The discharge current may also oscillate at the frequency determined by the charging capacitor and the discharge circuit inductance. Each half cycle of high-current current pulses exhibits a fast (≃10 ns) current rise when a spot is formed. It induces high frequency (10-100 MHz) transients and ringing oscillations in probes and current circuits. Most probes behave like unmatched antennas for the electromagnetic pulses of spot discharges. Examples are shown to distinguish the source of oscillations and some rf characteristics of Langmuir probes.

Operation regimes of a dielectric laser accelerator

NASA Astrophysics Data System (ADS)

Hanuka, Adi; Schächter, Levi

2018-04-01

We investigate three operation regimes in dielectric laser driven accelerators: maximum efficiency, maximum charge, and maximum loaded gradient. We demonstrate, using a self-consistent approach, that loaded gradients of the order of 1 to 6 [GV/m], efficiencies of 20% to 80%, and electrons flux of 1014 [el/s] are feasible, without significant concerns regarding damage threshold fluence. The latter imposes that the total charge per squared wavelength is constant (a total of 106 per μm2). We conceive this configuration as a zero-order design that should be considered for the road map of future accelerators.

Characteristic properties of the frame-antenna-produced RF discharge evolution in the Uragan-3M torsatron

NASA Astrophysics Data System (ADS)

Chechkin, V. V.; Grigor'eva, L. I.; Pavlichenko, R. O.; Kulaga, A. Ye.; Zamanov, N. V.; Moiseenko, V. E.; Burchenko, P. Ya.; Lozin, A. V.; Tsybenko, S. A.; Tarasov, I. K.; Pankratov, I. M.; Grekov, D. L.; Beletskii, A. A.; Kasilov, A. A.; Voitsenya, V. S.; Pashnev, V. K.; Konovalov, V. G.; Shapoval, A. N.; Mironov, Yu. K.; Romanov, V. S.

2014-08-01

In the ℓ = 3 Uragan-3M torsatron, hydrogen plasma is produced and heated by RF fields in the Alfvén range of frequencies (ω ≲ ω ci ). To this end, a frame antenna with a broad spectrum of generated parallel wavenumbers is used. The RF discharge evolution is studied experimentally at different values of the RF power fed to the antenna (the anode voltage of the oscillator and the antenna current) and the initial pressure of the fueling gas. It is shown that, depending on the antenna current and hydrogen pressure, the discharge can operate in two regimes differing in the plasma density, temperature, and particle loss. The change in the discharge regime with increasing anode voltage is steplike in character. The particular values of the anode voltage and pressure at which the change occurs are affected by RF preionization or breakdown stabilization by a microwave discharge. The obtained results will be used in future experiments to choose the optimal regimes of the frame-antenna-produced RF discharge as a target for the production and heating of a denser plasma by another, shorter wavelength three-half-turn antenna.

Evaluation of Spatial Pattern of Altered Flow Regimes on a River Network Using a Distributed Hydrological Model

PubMed Central

Ryo, Masahiro; Iwasaki, Yuichi; Yoshimura, Chihiro; Saavedra V., Oliver C.

2015-01-01

Alteration of the spatial variability of natural flow regimes has been less studied than that of the temporal variability, despite its ecological importance for river ecosystems. Here, we aimed to quantify the spatial patterns of flow regime alterations along a river network in the Sagami River, Japan, by estimating river discharge under natural and altered flow conditions. We used a distributed hydrological model, which simulates hydrological processes spatiotemporally, to estimate 20-year daily river discharge along the river network. Then, 33 hydrologic indices (i.e., Indicators of Hydrologic Alteration) were calculated from the simulated discharge to estimate the spatial patterns of their alterations. Some hydrologic indices were relatively well estimated such as the magnitude and timing of maximum flows, monthly median flows, and the frequency of low and high flow pulses. The accuracy was evaluated with correlation analysis (r > 0.4) and the Kolmogorov–Smirnov test (α = 0.05) by comparing these indices calculated from both observed and simulated discharge. The spatial patterns of the flow regime alterations varied depending on the hydrologic indices. For example, both the median flow in August and the frequency of high flow pulses were reduced by the maximum of approximately 70%, but these strongest alterations were detected at different locations (i.e., on the mainstream and the tributary, respectively). These results are likely caused by different operational purposes of multiple water control facilities. The results imply that the evaluation only at discharge gauges is insufficient to capture the alteration of the flow regime. Our findings clearly emphasize the importance of evaluating the spatial pattern of flow regime alteration on a river network where its discharge is affected by multiple water control facilities. PMID:26207997

Air-jet power ultrasonic field applied to electrical discharge

NASA Astrophysics Data System (ADS)

Balek, Rudolf; Pekarek, Stanislav

2010-01-01

We describe a new setup of the Hartmann air-jet ultrasonic generator combined with electrical discharge in the nozzle-resonator gap. Using the schlieren visualization of air jet and ultrasonic field we investigated the shape and structure of the discharge and we determined relationship among the acoustic field in the nozzle-resonator gap, generator ultrasonic emission and discharge behavior. Apart of the fact that the discharge in the nozzle-resonator gap is stabilized and becomes more uniform, it increases its volume when the generator works in the regime of ultrasonic emission. At the same time the discharge light emission distribution is more over uniform in the gap. In the regime without the ultrasonic emission the discharge light emission is fragmented. We also found that the impedance of the discharge is decreased in case when the generator works in the regime of ultrasonic emission.

Temporally, spatially, and spectrally resolved barrier discharge produced in trapped helium gas at atmospheric pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiper, Alina Silvia; Popa, Gheorghe

2013-06-07

Experimental study was made on induced effects by trapped helium gas in the pulsed positive dielectric barrier discharge (DBD) operating in symmetrical electrode configuration at atmospheric pressure. Using fast photography technique and electrical measurements, the differences in the discharge regimes between the stationary and the flowing helium are investigated. It was shown experimentally that the trapped gas atmosphere (TGA) has notable impact on the barrier discharge regime compared with the influence of the flowing gas atmosphere. According to our experimental results, the DBD discharge produced in trapped helium gas can be categorized as a multi-glow (pseudo-glow) discharge, each discharge workingmore » in the sub-normal glow regime. This conclusion is made by considering the duration of current pulse (few {mu}s), their maximum values (tens of mA), the presence of negative slope on the voltage-current characteristic, and the spatio-temporal evolution of the most representative excited species in the discharge gap. The paper focuses on the space-time distribution of the active species with a view to better understand the pseudo-glow discharge mechanism. The physical basis for these effects was suggested. A transition to filamentary discharge is suppressed in TGA mode due to the formation of supplementary source of seed electrons by surface processes (by desorption of electrons due to vibrationally excited nitrogen molecules, originated from barriers surfaces) rather than volume processes (by enhanced Penning ionisation). Finally, we show that the pseudo-glow discharge can be generated by working gas trapping only; maintaining unchanged all the electrical and constructive parameters.« less

Identifying microturbulence regimes in a TCV discharge making use of physical constraints on particle and heat fluxes

DOE PAGES

Mariani, Alberto; Brunner, S.; Dominski, J.; ...

2018-01-17

Reducing the uncertainty on physical input parameters derived from experimental measurements is essential towards improving the reliability of gyrokinetic turbulence simulations. This can be achieved by introducing physical constraints. Amongst them, the zero particle flux condition is considered here. A first attempt is also made to match as well the experimental ion/electron heat flux ratio. This procedure is applied to the analysis of a particular Tokamak à Configuration Variable discharge. A detailed reconstruction of the zero particle flux hyper-surface in the multi-dimensional physical parameter space at fixed time of the discharge is presented, including the effect of carbon as themore » main impurity. Both collisionless and collisional regimes are considered. Hyper-surface points within the experimental error bars are found. In conclusion, the analysis is done performing gyrokinetic simulations with the local version of the GENE code, computing the fluxes with a Quasi-Linear (QL) model and validating the QL results with non-linear simulations in a subset of cases.« less

Identifying microturbulence regimes in a TCV discharge making use of physical constraints on particle and heat fluxes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mariani, Alberto; Brunner, S.; Dominski, J.

Reducing the uncertainty on physical input parameters derived from experimental measurements is essential towards improving the reliability of gyrokinetic turbulence simulations. This can be achieved by introducing physical constraints. Amongst them, the zero particle flux condition is considered here. A first attempt is also made to match as well the experimental ion/electron heat flux ratio. This procedure is applied to the analysis of a particular Tokamak à Configuration Variable discharge. A detailed reconstruction of the zero particle flux hyper-surface in the multi-dimensional physical parameter space at fixed time of the discharge is presented, including the effect of carbon as themore » main impurity. Both collisionless and collisional regimes are considered. Hyper-surface points within the experimental error bars are found. In conclusion, the analysis is done performing gyrokinetic simulations with the local version of the GENE code, computing the fluxes with a Quasi-Linear (QL) model and validating the QL results with non-linear simulations in a subset of cases.« less

Influence of driving frequency on discharge modes in the dielectric barrier discharge excited by a triangle voltage

NASA Astrophysics Data System (ADS)

Li, Xuechen; Liu, Rui; Jia, Pengying; Wu, Kaiyue; Ren, Chenhua; Yin, Zengqian

2018-01-01

A one-dimensional fluid model in atmospheric pressure argon is employed to investigate the influence of the driving frequency on dielectric barrier discharge modes excited by a triangle voltage. Results indicate that a stepped discharge mode is obtained with a low driving frequency of 35 kHz. The current amplitude increases, while its plateau duration decreases with increasing the frequency. The stepped discharge transits into a multi-pulsed mode when the frequency is increased to 80 kHz. With its further increment, the pulse number decreases, and a double-pulsed discharge is realized at 90 kHz, which finally transits to a single-pulsed discharge. Through analyzing spatial distributions of electron density, ion density, and electric field, it can be concluded that the discharge regime transits from a Townsend-like discharge to a glow discharge with increasing the frequency. The regime transition is further verified by analyzing voltage-current curves. These simulated results are consistent with the experimental phenomena.

Wake meandering of a model wind turbine operating in two different regimes

NASA Astrophysics Data System (ADS)

Foti, Daniel; Yang, Xiaolei; Campagnolo, Filippo; Maniaci, David; Sotiropoulos, Fotis

2018-05-01

The flow behind a model wind turbine under two different turbine operating regimes (region 2 for turbine operating at optimal condition with the maximum power coefficient and 1.4-deg pitch angle and region 3 for turbine operating at suboptimal condition with a lower power coefficient and 7-deg pitch angle) is investigated using wind tunnel experiments and numerical experiments using large-eddy simulation (LES) with actuator surface models for turbine blades and nacelle. Measurements from the model wind turbine experiment reveal that the power coefficient and turbine wake are affected by the operating regime. Simulations with and without a nacelle model are carried out for each operating condition to study the influence of the operating regime and nacelle on the formation of the hub vortex and wake meandering. Statistics and energy spectra of the simulated wakes are in good agreement with the measurements. For simulations with a nacelle model, the mean flow field is composed of an outer wake, caused by energy extraction by turbine blades, and an inner wake directly behind the nacelle, while for the simulations without a nacelle model, the central region of the wake is occupied by a jet. The simulations with the nacelle model reveal an unstable helical hub vortex expanding outward toward the outer wake, while the simulations without a nacelle model show a stable and columnar hub vortex. Because of the different interactions of the inner region of the wake with the outer region of the wake, a region with higher turbulence intensity is observed in the tip shear layer for the simulation with a nacelle model. The hub vortex for the turbine operating in region 3 remains in a tight helical spiral and intercepts the outer wake a few diameters further downstream than for the turbine operating in region 2. Wake meandering, a low-frequency large-scale motion of the wake, commences in the region of high turbulence intensity for all simulations with and without a nacelle model

Characterization of novel pin-hole based plasma source for generation of discharge in liquids supplied by DC non-pulsing voltage

NASA Astrophysics Data System (ADS)

Krčma, F.; Kozáková, Z.; Mazánková, V.; Horák, J.; Dostál, L.; Obradović, B.; Nikiforov, A.; Belmonte, T.

2018-06-01

A recently presented novel plasma source generating discharge in liquids based on the pin-hole discharge configuration is characterized in detail. The system is supplied by DC non-pulsing high voltage of both polarities in NaCl water solutions at a conductivity range of 100–15 000 μS/cm. The discharge itself shows self-pulsing operation. The discharge ignition is observed in micro bubbles by transient discharge followed by a glow discharge in positive polarity at lower conductivities propagating inside the bubbles. At high conductivities, the glow regime is particularly replaced by a more energetic sequence of transient discharges followed by a shorter glow mode operation. The transient regime probability and its intensity are higher in the negative discharge polarity. The transient discharge produces acoustic waves and shock waves, which are observed at the moment of the bubble cavitation. The average gas temperature of 700–1500 K was calculated from the lowest OH (A-X) 0-0 band transitions. The average electron concentrations of 1020–1023 m‑3 were calculated from H α and H β line profiles. Finally, the production of a chemically active species is determined by hydrogen peroxide energy yields related to the energy consumption of the whole interelectrode system. All these quantities are dependent on the solution conductivity, the discharge polarity, and the applied power.

Wildfire vs. Agricultural Operations: A Tale of Overprinted Disturbance Regimes

NASA Astrophysics Data System (ADS)

Gray, A. B.; Pasternack, G. B.; Watson, E. B.; Warrick, J. A.; Hatten, J. A.; Goni, M. A.

2016-12-01

Punctuated disturbances, such as wildfire, compete with interdecadal scale changes to land surfaces, such as shifting agricultural practices, resulting in complex trends in the suspended sediment transport dynamics of watersheds. A powerful, though data intensive approach to identifying dominant disturbance regimes is the application of retrospective forensic analysis, whereby time series of major factors potentially affecting watershed expression are investigated. In the test case, a decreasing trend in discharge corrected suspended sediment concentrations was found in the lower Salinas River, California between 1967 and 2011. Event to decadal scale patterns in sediment production in the Salinas River have been found to be largely controlled by antecedent hydrologic conditions, but decreasing suspended sediment concentrations over the last 15 years of the record departed from those expected from hydro-climatic forcing. Sediment production from the mountainous headwaters of the central California Coast Ranges, which are drained in part by the Salinas River, is known to be dominated by the interaction of wildfire and large rainfall/runoff events. However, the decreasing trend in Salinas River suspended sediment concentrations run contrary to increases in the watershed's effective burn area over time. The departure from hydrologic and wildfire forcing on suspended sediment concentration patterns was found to coincide with a rapid conversion of irrigation practices from sprinkler and furrow to subsurface drip irrigation. Changes in agricultural operations appear to have decreased sediment supply to the Salinas River over late 20th to early 21st century; obscuring the influence of wildfire on suspended sediment production.

Effect of gas heating on the generation of an ultrashort avalanche electron beam in the pulse-periodic regime

NASA Astrophysics Data System (ADS)

Baksht, E. Kh.; Burachenko, A. G.; Lomaev, M. I.; Sorokin, D. A.; Tarasenko, V. F.

2015-07-01

The generation of an ultrashort avalanche electron beam (UAEB) in nitrogen in the pulse-periodic regime is investigated. The gas temperature in the discharge gap of the atmospheric-pressure nitrogen is measured from the intensity distribution of unresolved rotational transitions ( C 3Π u , v' = 0) → ( B 3Π g , v″ = 0) in the nitrogen molecule for an excitation pulse repetition rate of 2 kHz. It is shown that an increase in the UAEB current amplitude in the pulse-periodic regime is due to gas heating by a series of previous pulses, which leads to an increase in the reduced electric field strength as a result of a decrease in the gas density in the zone of the discharge formation. It is found that in the pulse-periodic regime and the formation of the diffuse discharge, the number of electrons in the beam increases by several times for a nitrogen pressure of 9 × 103 Pa. The dependences of the number of electrons in the UAEB on the time of operation of the generator are considered.

Physics and performance of the I-mode regime over an expanded operating space on Alcator C-Mod

NASA Astrophysics Data System (ADS)

Hubbard, A. E.; Baek, S.-G.; Brunner, D.; Creely, A. J.; Cziegler, I.; Edlund, E.; Hughes, J. W.; LaBombard, B.; Lin, Y.; Liu, Z.; Marmar, E. S.; Reinke, M. L.; Rice, J. E.; Sorbom, B.; Sung, C.; Terry, J.; Theiler, C.; Tolman, E. A.; Walk, J. R.; White, A. E.; Whyte, D.; Wolfe, S. M.; Wukitch, S.; Xu, X. Q.; the Alcator C-Mod Team

2017-12-01

New results on the I-mode regime of operation on the Alcator C-Mod tokamak are reported. This ELM-free regime features high energy confinement and a steep temperature pedestal, while particle confinement remains at L-mode levels, giving stationary density and avoiding impurity accumulation. I-mode has now been obtained over nearly all of the magnetic fields and currents possible in this high field tokamak (I p 0.55-1.7 MA, B T 2.8-8 T) using a configuration with B  ×  ∇ B drift away from the X-point. Results at 8 T confirm that the L-I power threshold varies only weakly with B T, and that the power range for I-mode increases with B T; no 8 T discharges transitioned to H-mode. Parameter dependences of energy confinement are investigated. Core transport simulations are giving insight into the observed turbulence reduction, profile stiffness and confinement improvement. Pedestal models explain the observed stability to ELMs, and can simulate the observed weakly coherent mode. Conditions for I-H transitions have complex dependences on density as well as power. I-modes have now been maintained in near-DN configurations, leading to improved divertor power flux sharing. Prospects for I-mode on future fusion devices such as ITER and ARC are encouraging. Further experiments on other tokamaks are needed to improve confidence in extrapolation.

DC corona discharge ozone production enhanced by magnetic field

NASA Astrophysics Data System (ADS)

Pekárek, S.

2010-01-01

We have studied the effect of a stationary magnetic field on the production of ozone from air at atmospheric pressure by a negative corona discharge in a cylindrical electrode configuration. We used a stainless steel hollow needle placed at the axis of the cylindrical discharge chamber as a cathode. The outer wall of the cylinder was used as an anode. The vector of magnetic induction was perpendicular to the vector of current density. We found that: (a) the magnetic field extends the current voltage range of the discharge; (b) for the discharge in the Trichel pulses regime and in the pulseless glow regime, the magnetic field has no substantial effect on the discharge voltage or on the concentration of ozone that is produced; (c) for the discharge in the filamentary streamer regime for a particular current, the magnetic field increases the discharge voltage and consequently an approximately 30% higher ozone concentration can be obtained; (d) the magnetic field does not substantially increase the maximum ozone production yield. A major advantage of using a magnetic field is that the increase in ozone concentration produced by the discharge can be obtained without additional energy requirements.

Systematic investigation of the barrier discharge operation in helium, nitrogen, and mixtures: discharge development, formation and decay of surface charges

NASA Astrophysics Data System (ADS)

Tschiersch, R.; Bogaczyk, M.; Wagner, H.-E.

2014-09-01

As a logical extension to previous investigations of the barrier discharge (BD) in helium and nitrogen, the present work reports on the operation in any mixtures of both pure gases. Using a well-established plane-parallel discharge cell configuration allows to study the influence of the He/N2 mixing ratio on the formation of different discharge modes. Their characterization was made by measuring the discharge emission development together with the formation and decay of surface charges on a bismuth silicon oxide (Bi12SiO20, BSO) crystal. This was realized by the simultaneous application of the spatio-temporally resolved optical emission spectroscopy, and the electro-optic Pockels effect in combination with a CCD high speed camera. The existence diagram for diffuse and filamentary BDs was determined by varying the amplitude and shape of the applied voltage. Over the entire range of the He/N2 ratio, the diffuse mode can be operated at moderate voltage amplitudes whereas filamentation occurs at significant overvoltage and is favoured by a high voltage slew rate. Irrespective of the discharge mode, the overall charge transfer during a discharge breakdown is found to be in excellent agreement with the amount of accumulated surface charges. An exponential decay of the surface charge deposited on the BSO crystal is induced by LED illumination beyond a typical discharge cycle. During the decay process, a broadening of the radial profiles of positive as well as negative surface charge spots originating from previous microdischarges is observed. The investigations contribute to a better understanding of the charge accumulation at a dielectric.

Energetic Ion Beam Production by a Low-Pressure Plasma Focus Discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, L. K.; Yap, S. L.; Wong, C. S.

Energetic ion beam emissions in a 3 kJ Mather type plasma focus operating at low-pressure regime are investigated. Deuterium gas is used and the discharge is operated in a low-pressure regime of below 1 mbar. Formation of the current sheath during the breakdown phase at the back wall is assisted by a set delayed trigger pulse. Energetic and intense ion beams with good reproducibility have been obtained for the operating pressure ranging from 0.05 mbar to 0.5 mbar. Deuteron beam is determined by time resolved measurement by making use of three biased ion collectors placed at the end on direction.more » The average energies of deuteron beams are resolved by using time-of flight method. Correlation between the ion emissions and the current sheath dynamics is also discussed.« less

A Compact Source of Flash-Corona Discharge for Biomedical Applications

NASA Astrophysics Data System (ADS)

Moshkunov, S. I.; Khomich, V. Yu.; Shershunova, E. A.

2018-01-01

A compact source of low-temperature plasma for biological and medical applications is proposed, which operates at kilohertz frequencies in the regime of flash-corona discharge with an energy of 0.1 mJ/pulse. The plasma source was tested in application to plasma pretreatment of green salad seeds. Plasma-treated seeds exhibited increased (by about 25%) germination speed as compared to that in the untreated control.

Infrasound reveals transition to oscillatory discharge regime during lava fountaining: Implication for early warning

NASA Astrophysics Data System (ADS)

Ulivieri, Giacomo; Ripepe, Maurizio; Marchetti, Emanuele

2013-06-01

present the analysis of ~4 million infrasonic signals which include 39 episodes of lava fountains recorded at 5.5 km from the active vents. We show that each eruptive episode is characterized by a distinctive trend in the amplitude, waveform, and frequency content of the acoustic signals, reflecting different explosive levels. Lava fountain starts with an ~93 min long violent phase of acoustic transients at ~1.25 Hz repeating every 2-5 s. Infrasound suddenly evolves into a persistent low-frequency quasi-monochromatic pressure oscillation at ~0.4 Hz. We interpret this shift as induced by the transition from the slug (discrete Strombolian) to churn flow (sustained lava fountain) regime that is reflecting an increase in the gas discharge rate. We calculate that infrasonic transition can occur at a gas superficial velocity of ≤76 m/s and it can be used to define infrasonic-based thresholds for an efficient early warning system.

46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

Burning plasma regime for Fussion-Fission Research Facility

NASA Astrophysics Data System (ADS)

Zakharov, Leonid E.

2010-11-01

The basic aspects of burning plasma regimes of Fusion-Fission Research Facility (FFRF, R/a=4/1 m/m, Ipl=5 MA, Btor=4-6 T, P^DT=50-100 MW, P^fission=80-4000 MW, 1 m thick blanket), which is suggested as the next step device for Chinese fusion program, are presented. The mission of FFRF is to advance magnetic fusion to the level of a stationary neutron source and to create a technical, scientific, and technology basis for the utilization of high-energy fusion neutrons for the needs of nuclear energy and technology. FFRF will rely as much as possible on ITER design. Thus, the magnetic system, especially TFC, will take advantage of ITER experience. TFC will use the same superconductor as ITER. The plasma regimes will represent an extension of the stationary plasma regimes on HT-7 and EAST tokamaks at ASIPP. Both inductive discharges and stationary non-inductive Lower Hybrid Current Drive (LHCD) will be possible. FFRF strongly relies on new, Lithium Wall Fusion (LiWF) plasma regimes, the development of which will be done on NSTX, HT-7, EAST in parallel with the design work. This regime will eliminate a number of uncertainties, still remaining unresolved in the ITER project. Well controlled, hours long inductive current drive operation at P^DT=50-100 MW is predicted.

ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts.

PubMed

Yang, Wenming; Zhu, Rong; Zong, Xianli

2016-12-01

Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 10(17)/m(3) orders of magnitude, which is practicable for most discharging applications.

The operating regime in mechanical pulps--the significance of fiber failure

Treesearch

Lauri K. Lehtonen; Alan W. Rudie; Douglas W. Coffin; Derek H. Page

2004-01-01

In order to circumvent the problem of altering the sheet composition to increase bonding, in this study the bonding was increased by wet pressing and press drying sheets to various levels of RBA. The operating regime problem was then studied by interpreting the tear relative to bonding (where bonding is measured as T/Z, Tensile index/Zero span tensile index)...

Effects of dam operation on the endangered Júcar nase, Parachondrostoma arrigonis, related to mesohabitats, microhabitat availability and water temperature regime, in the river Cabriel (Spain)

NASA Astrophysics Data System (ADS)

Martinez-Capel, Francisco; Costa, Rui; Muñoz-Mas, Rafael; Diego Alcaraz-Hernandez, Juan; Hernandez-Mascarell, Aina

2010-05-01

The presence of large dams affects habitat availability, often regarded as the primary factor that limits population and community recovery in rivers. Physical habitat is often targeted in restoration, but there is often a paucity of useful information. Habitat degradation has reduced the complexity and connectivity of the Mediterranean streams in Spain. These changes have diminished the historical range of the endangered Júcar nase, Parachondrostoma arrigonis (Steindachner, 1866), isolated the populations of this species, and probably contributed to its risk of extinction. In the Júcar River basin (Spain), where this fish is endemic, the populations are mainly restricted to the river Cabriel, which is fragmented in two segments by the large dam of Contreras. In this river, 3 main lines of research were developed from 2006 to 2008, i.e., microhabitat suitability, mesohabitat suitability, and water temperature, in order to relate such kind of variables with the flow regime. The main goal of the research project, funded by the Spanish Ministry of Environment, was to detect the main reasons of the species decline, and to propose dam operation improvements to contribute to the recovery of the species. The flow and water temperature regimes were also studied in the river Cabriel, upstream and downstream the large dam of Contreras. During the three years of study, below the dam it was observed a small and not significant variation in the proportions of slow and fast habitats; the regulated flow regime was pointed out as the main reason of such variations. At the microhabitat scale, optimal ranges for average depth and velocity were defined; these data allowed us to develop an estimation of weighted useable area under natural and regulated conditions. The Júcar nase were found majorly at depths no greater than 1,15 meters with slow water velocities. It was possible to observe a clear alteration of the flow and water temperature regime below the dam, due to the cold

Application of Effective Discharge Analysis to Environmental Flow Decision-Making.

PubMed

McKay, S Kyle; Freeman, Mary C; Covich, Alan P

2016-06-01

Well-informed river management decisions rely on an explicit statement of objectives, repeatable analyses, and a transparent system for assessing trade-offs. These components may then be applied to compare alternative operational regimes for water resource infrastructure (e.g., diversions, locks, and dams). Intra- and inter-annual hydrologic variability further complicates these already complex environmental flow decisions. Effective discharge analysis (developed in studies of geomorphology) is a powerful tool for integrating temporal variability of flow magnitude and associated ecological consequences. Here, we adapt the effectiveness framework to include multiple elements of the natural flow regime (i.e., timing, duration, and rate-of-change) as well as two flow variables. We demonstrate this analytical approach using a case study of environmental flow management based on long-term (60 years) daily discharge records in the Middle Oconee River near Athens, GA, USA. Specifically, we apply an existing model for estimating young-of-year fish recruitment based on flow-dependent metrics to an effective discharge analysis that incorporates hydrologic variability and multiple focal taxa. We then compare three alternative methods of environmental flow provision. Percentage-based withdrawal schemes outcompete other environmental flow methods across all levels of water withdrawal and ecological outcomes.

Application of effective discharge analysis to environmental flow decision-making

USGS Publications Warehouse

McKay, S. Kyle; Freeman, Mary C.; Covich, A.P.

2016-01-01

Well-informed river management decisions rely on an explicit statement of objectives, repeatable analyses, and a transparent system for assessing trade-offs. These components may then be applied to compare alternative operational regimes for water resource infrastructure (e.g., diversions, locks, and dams). Intra- and inter-annual hydrologic variability further complicates these already complex environmental flow decisions. Effective discharge analysis (developed in studies of geomorphology) is a powerful tool for integrating temporal variability of flow magnitude and associated ecological consequences. Here, we adapt the effectiveness framework to include multiple elements of the natural flow regime (i.e., timing, duration, and rate-of-change) as well as two flow variables. We demonstrate this analytical approach using a case study of environmental flow management based on long-term (60 years) daily discharge records in the Middle Oconee River near Athens, GA, USA. Specifically, we apply an existing model for estimating young-of-year fish recruitment based on flow-dependent metrics to an effective discharge analysis that incorporates hydrologic variability and multiple focal taxa. We then compare three alternative methods of environmental flow provision. Percentage-based withdrawal schemes outcompete other environmental flow methods across all levels of water withdrawal and ecological outcomes.

Basal Resources in Backwaters of the Colorado River Below Glen Canyon Dam-Effects of Discharge Regimes and Comparison with Mainstem Depositional Environments

USGS Publications Warehouse

Behn, Katherine E.; Kennedy, Theodore A.; Hall, Robert O.

2010-01-01

Eight species of fish were native to the Colorado River before the closure of Glen Canyon Dam, but only four of these native species are currently present. A variety of factors are responsible for the loss of native fish species and the limited distribution and abundance of those that remain. These factors include cold and constant water temperatures, predation and competition with nonnative fish species, and food limitation. Backwaters are areas of stagnant flow in a return-current channel and are thought to be critical rearing habitat for juvenile native fish. Backwaters can be warmer than the main channel and may support higher rates of food production. Glen Canyon Dam is a peaking hydropower facility and, as a result, has subdaily variation in discharge because of changes in demand for power. Stable daily discharges may improve the quality of nearshore rearing habitats such as backwaters by increasing warming, stabilizing the substrate, and increasing food production. To evaluate whether backwaters have greater available food resources than main-channel habitats, and how resource availability in backwaters is affected by stable flow regimes, we quantified water-column and benthic food resources in backwaters seasonally for 1 year using both standing (organic matter concentration/density; chlorophyll a concentration/density; zooplankton concentration; benthic invertebrate density and biomass) and process measurements (chamber estimates of ecosystem metabolism). We compared backwater resource measurements with comparable data from main-channel habitats, and compared backwater data collected during stable discharge with data collected when there was subdaily variation in discharge. Rates of primary production in backwaters (mean gross primary production of 1.7 g O2/m2/d) and the main channel (mean gross primary production of 2.0 g O2/m2/d) were similar. Benthic organic matter standing stock (presented as ash-free dry mass-AFDM) was seven times higher in backwaters

Stable operating regime for traveling wave devices

DOEpatents

Carlsten, Bruce E.

2000-01-01

Autophase stability is provided for a traveling wave device (TWD) electron beam for amplifying an RF electromagnetic wave in walls defining a waveguide for said electromagnetic wave. An off-axis electron beam is generated at a selected energy and has an energy noise inherently arising from electron gun. The off-axis electron beam is introduced into the waveguide. The off-axis electron beam is introduced into the waveguide at a second radius. The waveguide structure is designed to obtain a selected detuning of the electron beam. The off-axis electron beam has a velocity and the second radius to place the electron beam at a selected distance from the walls defining the waveguide, wherein changes in a density of the electron beam due to the RF electromagnetic wave are independent of the energy of the electron beam to provide a concomitant stable operating regime relative to the energy noise.

Effective discharge analysis of ecological processes in streams

USGS Publications Warehouse

Doyle, Martin W.; Stanley, Emily H.; Strayer, David L.; Jacobson, Robert B.; Schmidt, John C.

2005-01-01

Discharge is a master variable that controls many processes in stream ecosystems. However, there is uncertainty of which discharges are most important for driving particular ecological processes and thus how flow regime may influence entire stream ecosystems. Here the analytical method of effective discharge from fluvial geomorphology is used to analyze the interaction between frequency and magnitude of discharge events that drive organic matter transport, algal growth, nutrient retention, macroinvertebrate disturbance, and habitat availability. We quantify the ecological effective discharge using a synthesis of previously published studies and modeling from a range of study sites. An analytical expression is then developed for a particular case of ecological effective discharge and is used to explore how effective discharge varies within variable hydrologic regimes. Our results suggest that a range of discharges is important for different ecological processes in an individual stream. Discharges are not equally important; instead, effective discharge values exist that correspond to near modal flows and moderate floods for the variable sets examined. We suggest four types of ecological response to discharge variability: discharge as a transport mechanism, regulator of habitat, process modulator, and disturbance. Effective discharge analysis will perform well when there is a unique, essentially instantaneous relationship between discharge and an ecological process and poorly when effects of discharge are delayed or confounded by legacy effects. Despite some limitations the conceptual and analytical utility of the effective discharge analysis allows exploring general questions about how hydrologic variability influences various ecological processes in streams.

Generation of whistler-wave heated discharges with planar resonant RF networks.

PubMed

Guittienne, Ph; Howling, A A; Hollenstein, Ch

2013-09-20

Magnetized plasma discharges generated by a planar resonant rf network are investigated. A regime transition is observed above a magnetic field threshold, associated with rf waves propagating in the plasma and which present the characteristics of whistler waves. These wave heated regimes can be considered as analogous to conventional helicon discharges, but in planar geometry.

Discharge coefficient correlations for circular-arc venturi flowmeters at critical /sonic/ flow

NASA Technical Reports Server (NTRS)

Arnberg, B. T.; Britton, C. L.; Seidl, W. F.

1973-01-01

Experimental data are analyzed to support theoretical predictions for discharge coefficients in circular-arc venturi flow meters operating in the critical sonic flow regime at throat Reynolds numbers above 150 thousand. The data tend to verify the predicted 0.25% decrease in the discharge coefficient during transition from a laminar to turbulent boundary layer. Four different test gases and three flow measurement facilities were used in the experiments with 17 venturis with throat sizes from 0.15 to 1.37 in. and Beta ratios ranging from 0.014 to 0.25. Recommendations are given as to how the effectiveness of future studies in the field could be improved.

O-regime dynamics and modeling in Tore Supra

NASA Astrophysics Data System (ADS)

Turco, F.; Giruzzi, G.; Imbeaux, F.; Udintsev, V. S.; Artaud, J. F.; Barana, O.; Dumont, R.; Mazon, D.; Ségui, J.-L.

2009-06-01

The regime of nonlinear temperature oscillations (O-regime), characteristic of noninductive discharges on Tore Supra [Équipe Tore Supra, Proceedings of the 12th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Nice, France, 1988 (International Atomic Energy Agency, Vienna, 1989), Vol. 1, p. 9], is investigated in its triggering and suppressing mechanism. This regime can be described by two nonlinearly coupled equations for the current density j(r ) and the electron temperature Te(r) where the equation coefficients are functions of j and Te themselves. Both the integrated modeling code CRONOS [V. Basiuk et al., Nucl. Fusion 43, 822 (2003)] and a two-patch predator-prey system with diffusion and noise have been used and results have been compared to the experimental observations of the O-regime. A database of discharges is analyzed which features monotonic, flat, and reversed safety factor (q) profiles in order to characterize the action of external actuators on the regime dynamics with the widest generality. Electron cyclotron current drive and neutral beam injections have been used in order to induce localized perturbations in the total current profile j(r ) as well as to change the plasma confinement conditions in the central region. Magnetic shear perturbations and modifications of the heat transport turn out to be the central parameters governing the dynamics of the O-regime.

Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nad, Shreya; Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824; Gu, Yajun

2015-07-15

The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100–260 Torr pressure range and 1.5–2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficienciesmore » (η{sub coup}) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance.« less

Plasma in a Pulsed Discharge Environment

NASA Technical Reports Server (NTRS)

Remy, J.; Bienier, L.; Salama, F.

2005-01-01

The plasma generated in a pulsed slit discharge nozzle is used to form molecular ions in an astrophysically relevant environment. The plasma has been characterized as a glow discharge in the abnormal regime. Laboratory studies help understand the formation processes of polycyclic aromatic hydrocarbon (PAH) ions that are thought to be the source of the ubiquitous unidentified infrared bands.

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

Use of geomorphic regime diagrams in channel restoration

NASA Astrophysics Data System (ADS)

Buffington, J. M.; Parker, G.

2005-12-01

Regime diagrams can be used to predict channel characteristics (depth, grain size, slope) and reach-scale channel morphology (pool-riffle, plane-bed, etc.) as a function imposed values of discharge and bedload sediment supply. In terms of stream restoration, these diagrams can be used to set target values for creating or maintaining desired channel types and associated aquatic habitats or to assess the stable channel morphology for imposed watershed conditions. However, alluvial channels are dynamic and may move toward new states with interannual changes in discharge or sediment supply. These changes may be small-scale adjustments of channel dimensions, grain size, or slope, or they may be whole-sale metamorphosis to a new reach type. The degree of change likely depends on local physiography and the associated characteristic variations of discharge and sediment supply. We propose a framework for assessing the relative degree of channel stability in different physiographic settings using a regime diagram that is explicitly linked to rational equations for discharge and sediment supply. This approach allows a more dynamic representation of potential channel conditions that can be expected for a given restoration design (or for an existing channel), and links site conditions to discharge and sediment supply variability imposed by larger-scale basin conditions and physiography.

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

NASA Astrophysics Data System (ADS)

Gregor, Joseph Atilla

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

Champagne experiences various rhythmical bubbling regimes in a flute.

PubMed

Liger-Belair, Gérard; Tufaile, Alberto; Jeandet, Philippe; Sartorelli, José-Carlos

2006-09-20

Bubble trains are seen rising gracefully from a few points on the glass wall (called nucleation sites) whenever champagne is poured into a glass. As time passes during the gas-discharging process, the careful observation of some given bubble columns reveals that the interbubble distance may change suddenly, thus revealing different rhythmical bubbling regimes. Here, it is reported that the transitions between the different bubbling regimes of some nucleation sites during gas discharging is a process which may be ruled by a strong interaction between tiny gas pockets trapped inside the nucleation site and/or also by an interaction between the tiny bubbles just blown from the nucleation site.

Discharging dynamics in an electrolytic cell

NASA Astrophysics Data System (ADS)

Feicht, Sarah E.; Frankel, Alexandra E.; Khair, Aditya S.

2016-07-01

We analyze the dynamics of a discharging electrolytic cell comprised of a binary symmetric electrolyte between two planar, parallel blocking electrodes. When a voltage is initially applied, ions in the electrolyte migrate towards the electrodes, forming electrical double layers. After the system reaches steady state and the external current decays to zero, the applied voltage is switched off and the cell discharges, with the ions eventually returning to a uniform spatial concentration. At voltages on the order of the thermal voltage VT=kBT /q ≃25 mV, where kB is Boltzmann's constant, T is temperature, and q is the charge of a proton, experiments on surfactant-doped nonpolar fluids observe that the temporal evolution of the external current during charging and discharging is not symmetric [V. Novotny and M. A. Hopper, J. Electrochem. Soc. 126, 925 (1979), 10.1149/1.2129195; P. Kornilovitch and Y. Jeon, J. Appl. Phys. 109, 064509 (2011), 10.1063/1.3554445]. In fact, at sufficiently large voltages (several VT), the current during discharging is no longer monotonic: it displays a "reverse peak" before decaying in magnitude to zero. We analyze the dynamics of discharging by solving the Poisson-Nernst-Planck equations governing ion transport via asymptotic and numerical techniques in three regimes. First, in the "linear regime" when the applied voltage V is formally much less than VT, the charging and discharging currents are antisymmetric in time; however, the potential and charge density profiles during charging and discharging are asymmetric. The current evolution is on the R C timescale of the cell, λDL /D , where L is the width of the cell, D is the diffusivity of ions, and λD is the Debye length. Second, in the (experimentally relevant) thin-double-layer limit ɛ =λD/L ≪1 , there is a "weakly nonlinear" regime defined by VT≲V ≲VTln(1 /ɛ ) , where the bulk salt concentration is uniform; thus the R C timescale of the evolution of the current magnitude

Impact of air conditioning system operation on increasing gases emissions from automobile

NASA Astrophysics Data System (ADS)

Burciu, S. M.; Coman, G.

2016-08-01

The paper presents a study concerning the influence of air conditioning system operation on the increase of gases emissions from cars. The study focuses on urban operating regimes of the automobile, regimes when the engines have low loads or are operating at idling. Are presented graphically the variations of pollution emissions (CO, CO2, HC) depending of engine speed and the load on air conditioning system. Additionally are presented, injection duration, throttle position, the mechanical power required by the compressor of air conditioning system and the refrigerant pressure variation on the discharge path, according to the stage of charging of the air conditioning system.

Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat; Plasma Technology and Nuclear Fusion Research Unit, Chulalongkorn University, Bangkok

2015-04-24

Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) canmore » be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.« less

Stage-Discharge Relations for the Colorado River in Glen, Marble, and Grand Canyons, Arizona, 1990-2005

USGS Publications Warehouse

Hazel, Joseph E.; Kaplinski, Matt; Parnell, Rod; Kohl, Keith; Topping, David J.

2007-01-01

This report presents stage-discharge relations for 47 discrete locations along the Colorado River, downstream from Glen Canyon Dam. Predicting the river stage that results from changes in flow regime is important for many studies investigating the effects of dam operations on resources in and along the Colorado River. The empirically based stage-discharge relations were developed from water-surface elevation data surveyed at known discharges at all 47 locations. The rating curves accurately predict stage at each location for discharges between 141 cubic meters per second and 1,274 cubic meters per second. The coefficient of determination (R2) of the fit to the data ranged from 0.993 to 1.00. Given the various contributing errors to the method, a conservative error estimate of ?0.05 m was assigned to the rating curves.

33 CFR 151.69 - Operating requirements: Discharge of garbage outside special areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION VESSELS CARRYING OIL, NOXIOUS LIQUID SUBSTANCES... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage Pollution and Sewage § 151.69 Operating requirements: Discharge of garbage outside special areas. (a) When...

33 CFR 151.69 - Operating requirements: Discharge of garbage outside special areas.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION VESSELS CARRYING OIL, NOXIOUS LIQUID SUBSTANCES... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage Pollution and Sewage § 151.69 Operating requirements: Discharge of garbage outside special areas. (a) When...

33 CFR 151.69 - Operating requirements: Discharge of garbage outside special areas.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION VESSELS CARRYING OIL, NOXIOUS LIQUID SUBSTANCES... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage Pollution and Sewage § 151.69 Operating requirements: Discharge of garbage outside special areas. (a) When...

Dielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single filaments

NASA Astrophysics Data System (ADS)

Brandenburg, Ronny

2017-05-01

Dielectric barrier discharges (DBDs) are plasmas generated in configurations with an insulating (dielectric) material between the electrodes which is responsible for a self-pulsing operation. DBDs are a typical example of nonthermal atmospheric or normal pressure gas discharges. Initially used for the generation of ozone, they have opened up many other fields of application. Therefore DBDs are a relevant tool in current plasma technology as well as an object for fundamental studies. Another motivation for further research is the fact that so-called partial discharges in insulated high voltage systems are special types of DBDs. The breakdown processes, the formation of structures, and the role of surface processes are currently under investigation. This review is intended to give an update to the already existing literature on DBDs considering the research and development within the last two decades. The main principles and different modes of discharge generation are summarized. A collection of known as well as special electrode configurations and reactor designs will be presented. This shall demonstrate the different and broad possibilities, but also the similarities and common aspects of devices for different fields of applications explored within the last years. The main part is devoted to the progress on the investigation of different aspects of breakdown and plasma formation with the focus on single filaments or microdischarges. This includes a summary of the current knowledge on the electrical characterization of filamentary DBDs. In particular, the recent new insights on the elementary volume and surface memory mechanisms in these discharges will be discussed. An outlook for the forthcoming challenges on research and development will be given.

Super H-mode: theoretical prediction and initial observations of a new high performance regime for tokamak operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, Philip B.; Solomon, Wayne M.; Burrell, Keith H.

2015-07-21

A new “Super H-mode” regime is predicted, which enables pedestal height and predicted fusion performance substantially higher than for H-mode operation. This new regime is predicted to exist by the EPED pedestal model, which calculates criticality constraints for peeling-ballooning and kinetic ballooning modes, and combines them to predict the pedestal height and width. EPED usually predicts a single (“H-mode”) pedestal solution for each set of input parameters, however, in strongly shaped plasmas above a critical density, multiple pedestal solutions are found, including the standard “Hmode” solution, and a “Super H-Mode” solution at substantially larger pedestal height and width. The Supermore » H-mode regime is predicted to be accessible by controlling the trajectory of the density, and to increase fusion performance for ITER, as well as for DEMO designs with strong shaping. A set of experiments on DIII-D has identified the predicted Super H-mode regime, and finds pedestal height and width, and their variation with density, in good agreement with theoretical predictions from the EPED model. Finally, the very high pedestal enables operation at high global beta and high confinement, including the highest normalized beta achieved on DIII-D with a quiescent edge.« less

Development of an inflow controlled environmental flow regime for a Norwegian river

NASA Astrophysics Data System (ADS)

Alfredsen, Knut; Harby, Atle; Linnansaari, Tommi; Ugedal, Ola

2010-05-01

For most regulated rivers in Norway the common environmental flow regime is static and shows very little variation over the year. Recent research indicate that flow regimes that follow the natural inflow variation can meet the ecological and social demands for water in a better way. The implementation of a variable environmental flow regime provides many challenges both related to defining flow for various species and user groups in the river, but also due to practical implementation, legislation and control. A inflow controlled flow regime is developed for a Norwegian river regulated for hydro power as a pilot study. The regime should meet ecological demands from Atlantic salmon and brown trout, recreational use of water and visual impression of the river. This should be achieved preferably without altering the energy production in the hydro power system. The flow regime is developed for wet, dry and normal discharge conditions based on unregulated inflow to the catchment. The development of the seasonal flow requirements for various targets identified is done using a modification of the Building Block Method. Several options are tested regarding the integration of the flow regime into the operational strategy of the hydropower plant, both using real time prognosis of inflow and combinations with historical data. An important topic in selecting the release strategy is how it meets current Norwegian legislation and how well future documentation and environmental control can be carried out. An evaluation protocol is also proposed for the flow regime to test if the ecological targets are met.

Effects of flow regime on benthic algae and macroinvertebrates - A comparison between regulated and unregulated rivers.

PubMed

Schneider, Susanne C; Petrin, Zlatko

2017-02-01

Natural fluctuations in flow are important for maintaining the ecological integrity of riverine ecosystems. However, the flow regime of many rivers has been modified. We assessed the impact of water chemistry, habitat and streamflow characteristics on macroinvertebrates and benthic algae, comparing 20 regulated with 20 unregulated sites. Flow regime, calculated from daily averaged discharge over the five years preceding sampling, was generally more stable at regulated sites, with higher relative discharges in winter, lower relative discharges in spring and smaller differences between upper and lower percentiles. However, no consistent differences in benthic algal or macroinvertebrate structural and functional traits occurred between regulated and unregulated sites. When regulated and unregulated sites were pooled, overall flow regime, calculated as principal components of discharge characteristics over the five years preceding sampling, affected macroinvertebrate species assemblages, but not indices used for ecosystem status assessment or functional feeding groups. This indicates that, while species identity shifted with changing flow regime, the exchanged taxa had similar feeding habits. In contrast to macroinvertebrates, overall flow regime did not affect benthic algae. Our results indicate that overall flow regime affected the species pool of macroinvertebrates from which recolonization after extreme events may occur, but not of benthic algae. When individual components of flow regime were analyzed separately, high June (i.e. three months before sampling) flow maxima were associated with low benthic algal taxon richness, presumably due to scouring. Macroinvertebrate taxon richness decreased with lower relative minimum discharges, presumably due to temporary drying of parts of the riverbed. However, recolonization after such extreme events presumably is fast. Generally, macroinvertebrate and benthic algal assemblages were more closely related to water physico

In situ CF3 Detection in Low Pressure Inductive Discharges by Fourier Transform Infrared Spectroscopy

NASA Technical Reports Server (NTRS)

Kim, J. S.; Cappelli, M. A.; Sharma, S. P.; Arnold, J. O. (Technical Monitor)

1998-01-01

The detection of CF(x) (x=1-3) radicals in low pressure discharges using source gases such as CF4 and CHF3 is of importance to the understanding of their chemical structure and relevance in plasma based etching processes. These radicals are known to contribute to the formation of fluorocarbon polymer films, which affect the selectivity and anisotropy of etching. In this study, we present preliminary results of the quantitative measurement of trifluoromethyl radicals, CF3, in low pressure discharges. The discharge studied here is an inductively (transformer) coupled plasma (ICP) source in the GEC reference cell, operating on pure CF4 at pressures ranging from 10 - 100 mTorr, This plasma source generates higher electron number densities at lower operating pressures than obtainable with the parallel-plate capacitively coupled version of the GEC reference cell. Also, this expanded operating regime is more relevant to new generations of industrial plasma reactors being used by the microelectronics industry. Fourier transform infrared (FTIR) spectroscopy is employed to observe the absorption band of CF3 radicals in the electronic ground state X2Al in the region of 1233-1270/cm. The spectrometer is equipped with a high sensitivity HgCdTe (MCT) detector and has a fixed resolution of 0.125/cm. The CF3 concentrations are measured for a range of operating pressures and discharge power levels.

Direct current microhollow cathode discharges on silicon devices operating in argon and helium

NASA Astrophysics Data System (ADS)

Michaud, R.; Felix, V.; Stolz, A.; Aubry, O.; Lefaucheux, P.; Dzikowski, S.; Schulz-von der Gathen, V.; Overzet, L. J.; Dussart, R.

2018-02-01

Microhollow cathode discharges have been produced on silicon platforms using processes usually used for MEMS fabrication. Microreactors consist of 100 or 150 μm-diameter cavities made from Ni and SiO2 film layers deposited on a silicon substrate. They were studied in the direct current operating mode in two different geometries: planar and cavity configuration. Currents in the order of 1 mA could be injected in microdischarges operating in different gases such as argon and helium at a working pressure between 130 and 1000 mbar. When silicon was used as a cathode, the microdischarge operation was very unstable in both geometry configurations. Strong current spikes were produced and the microreactor lifetime was quite short. We evidenced the fast formation of blisters at the silicon surface which are responsible for the production of these high current pulses. EDX analysis showed that these blisters are filled with argon and indicate that an implantation mechanism is at the origin of this surface modification. Reversing the polarity of the microdischarge makes the discharge operate stably without current spikes, but the discharge appearance is quite different from the one obtained in direct polarity with the silicon cathode. By coating the silicon cathode with a 500 nm-thick nickel layer, the microdischarge becomes very stable with a much longer lifetime. No current spikes are observed and the cathode surface remains quite smooth compared to the one obtained without coating. Finally, arrays of 76 and 576 microdischarges were successfully ignited and studied in argon. At a working pressure of 130 mbar, all microdischarges are simultaneously ignited whereas they ignite one by one at higher pressure.

Comparison between off-resonance and electron Bernstein waves heating regime in a microwave discharge ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro, G.; Di Giugno, R.; Miracoli, R.

2012-02-15

A microwave discharge ion source (MDIS) operating at the Laboratori Nazionali del Sud of INFN, Catania has been used to compare the traditional electron cyclotron resonance (ECR) heating with an innovative mechanisms of plasma ignition based on the electrostatic Bernstein waves (EBW). EBW are obtained via the inner plasma electromagnetic-to-electrostatic wave conversion and they are absorbed by the plasma at cyclotron resonance harmonics. The heating of plasma by means of EBW at particular frequencies enabled us to reach densities much larger than the cutoff ones. Evidences of EBW generation and absorption together with X-ray emissions due to high energy electronsmore » will be shown. A characterization of the discharge heating process in MDISs as a generalization of the ECR heating mechanism by means of ray tracing will be shown in order to highlight the fundamental physical differences between ECR and EBW heating.« less

Zero dimensional model of atmospheric SMD discharge and afterglow in humid air

NASA Astrophysics Data System (ADS)

Smith, Ryan; Kemaneci, Efe; Offerhaus, Bjoern; Stapelmann, Katharina; Peter Brinkmann, Ralph

2016-09-01

A novel mesh-like Surface Micro Discharge (SMD) device designed for surface wound treatment is simulated by multiple time-scaled zero-dimensional models. The chemical dynamics of the discharge are resolved in time at atmospheric pressure in humid conditions. Simulated are the particle densities of electrons, 26 ionic species, and 26 reactive neutral species including: O3, NO, and HNO3. The total of 53 described species are constrained by 624 reactions within the simulated plasma discharge volume. The neutral species are allowed to diffuse into a diffusive gas regime which is of primary interest. Two interdependent zero-dimensional models separated by nine orders of magnitude in temporal resolution are used to accomplish this; thereby reducing the computational load. Through variation of control parameters such as: ignition frequency, deposited power density, duty cycle, humidity level, and N2 content, the ideal operation conditions for the SMD device can be predicted. The described model has been verified by matching simulation parameters and comparing results to that of previous works. Current operating conditions of the experimental mesh-like SMD were matched and results are compared to the simulations. Work supported by SFB TR 87.

Analytic theory of alternate multilayer gratings operating in single-order regime.

PubMed

Yang, Xiaowei; Kozhevnikov, Igor V; Huang, Qiushi; Wang, Hongchang; Hand, Matthew; Sawhney, Kawal; Wang, Zhanshan

2017-07-10

Using the coupled wave approach (CWA), we introduce the analytical theory for alternate multilayer grating (AMG) operating in the single-order regime, in which only one diffraction order is excited. Differing from previous study analogizing AMG to crystals, we conclude that symmetrical structure, or equal thickness of the two multilayer materials, is not the optimal design for AMG and may result in significant reduction in diffraction efficiency. The peculiarities of AMG compared with other multilayer gratings are analyzed. An influence of multilayer structure materials on diffraction efficiency is considered. The validity conditions of analytical theory are also discussed.

A Practice-Oriented Bifurcation Analysis for Pulse Energy Converters. Part 2: An Operating Regime

NASA Astrophysics Data System (ADS)

Kolokolov, Yury; Monovskaya, Anna

The paper continues the discussion on bifurcation analysis for applications in practice-oriented solutions for pulse energy conversion systems (PEC-systems). Since a PEC-system represents a nonlinear object with a variable structure, then the description of its dynamics evolution involves bifurcation analysis conceptions. This means the necessity to resolve the conflict-of-units between the notions used to describe natural evolution (i.e. evolution of the operating process towards nonoperating processes and vice versa) and the notions used to describe a desirable artificial regime (i.e. an operating regime). We consider cause-effect relations in the following sequence: nonlinear dynamics-output signal-operating characteristics, where these characteristics include stability and performance. Then regularities of nonlinear dynamics should be translated into regularities of the output signal dynamics, and, after, into an evolutional picture of each operating characteristic. In order to make the translation without losses, we first take into account heterogeneous properties within the structures of the operating process in the parametrical (P-) and phase (X-) spaces, and analyze regularities of the operating stability and performance on the common basis by use of the modified bifurcation diagrams built in joint PX-space. Then, the correspondence between causes (degradation of the operating process stability) and effects (changes of the operating characteristics) is decomposed into three groups of abnormalities: conditionally unavoidable abnormalities (CU-abnormalities); conditionally probable abnormalities (CP-abnormalities); conditionally regular abnormalities (CR-abnormalities). Within each of these groups the evolutional homogeneity is retained. After, the resultant evolution of each operating characteristic is naturally aggregated through the superposition of cause-effect relations in accordance with each of the abnormalities. We demonstrate that the practice

Statistical properties of the radiation from SASE FEL operating in the linear regime

NASA Astrophysics Data System (ADS)

Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

1998-02-01

The paper presents comprehensive analysis of statistical properties of the radiation from self amplified spontaneous emission (SASE) free electron laser operating in linear mode. The investigation has been performed in a one-dimensional approximation, assuming the electron pulse length to be much larger than a coherence length of the radiation. The following statistical properties of the SASE FEL radiation have been studied: field correlations, distribution of the radiation energy after monochromator installed at the FEL amplifier exit and photoelectric counting statistics of SASE FEL radiation. It is shown that the radiation from SASE FEL operating in linear regime possesses all the features corresponding to completely chaotic polarized radiation.

76 FR 65431 - National Pollutant Discharge Elimination System (NPDES) Concentrated Animal Feeding Operation...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-21

...-AF22 National Pollutant Discharge Elimination System (NPDES) Concentrated Animal Feeding Operation... co-proposes two options for obtaining basic information from CAFOs to support EPA in meeting its water quality protection responsibilities under the Clean Water Act (CWA). The purpose of this co...

Dynamics and density distributions in a capillary-discharge waveguide with an embedded supersonic jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlis, N. H., E-mail: nmatlis@gmail.com; Gonsalves, A. J.; Steinke, S.

We present an analysis of the gas dynamics and density distributions within a capillary-discharge waveguide with an embedded supersonic jet. This device provides a target for a laser plasma accelerator which uses longitudinal structuring of the gas-density profile to enable control of electron trapping and acceleration. The functionality of the device depends sensitively on the details of the density profile, which are determined by the interaction between the pulsed gas in the jet and the continuously-flowing gas in the capillary. These dynamics are captured by spatially resolving recombination light from several emission lines of the plasma as a function ofmore » the delay between the jet and the discharge. We provide a phenomenological description of the gas dynamics as well as a quantitative evaluation of the density evolution. In particular, we show that the pressure difference between the jet and the capillary defines three regimes of operation with qualitatively different longitudinal density profiles and show that jet timing provides a sensitive method for tuning between these regimes.« less

Self-organized criticality: An interplay between stable and turbulent regimes of multiple anodic double layers in glow discharge plasma

NASA Astrophysics Data System (ADS)

Alex, Prince; Carreras, Benjamin Andres; Arumugam, Saravanan; Sinha, Suraj Kumar

2018-05-01

The role of self-organized criticality (SOC) in the transformation of multiple anodic double layers (MADLs) from the stable to turbulent regime has been investigated experimentally as the system approaches towards critical behavior. The experiment was performed in a modified glow discharge plasma setup, and the initial stable state of MADL comprising three concentric perceptible layers was produced when the drift velocity of electrons towards the anode exceeds the electron thermal velocity (νd ≥ 1.3νte). The macroscopic arrangement of both positive and negative charges in opposite layers of MADL is attributed to the self-organization scenario. Beyond νd ≥ 3νte, MADL begins to collapse and approaches critical and supercritical states through layer reduction which continue till the last remaining layer of the double layer is transformed into a highly unstable radiant anode glow. The avalanche resulting from the collapse of MADL leads to the rise of turbulence in the system. Long-range correlations, a key signature of SOC, have been explored in the turbulent floating potential fluctuations using the rescaled-range analysis technique. The result shows that the existence of the self-similarity regime with self-similarity parameter H varies between 0.55 and 0.91 for time lags longer than the decorrelation time. The power law tail in the rank function, slowly decaying tail of the autocorrelation function, and 1/f behavior of the power spectra of the fluctuations are consistent with the fact that SOC plays a conclusive role in the transformation of MADL from the stable to turbulent regime. Since the existence of SOC gives a measure of complexity in the system, the result provides the condition under which complexity arises in cold plasma.

A bank-operated traveling-block cableway for stream discharge and sediment measurements

Treesearch

James J. Paradiso

2000-01-01

Streams often present a challenge for collecting flow and sediment measurements on a year-round basis. Streams that can normally be waded become hazardous during seasonal flows, either endangering hydrographers or precluding data collection completely. A hand-operated cableway permits the accurate and safe collection of discharge and sediment data from the stream bank...

Spatial-temporal evolution of self-organized loop-patterns on a water surface and a diffuse discharge in the gap

NASA Astrophysics Data System (ADS)

Li, Xuechen; Geng, Jinling; Jia, Pengying; Zhang, Panpan; Zhang, Qi; Li, Yaru

2017-11-01

Excited by an alternating current voltage, a patterned discharge and a diffuse discharge are generated in a needle to liquid configuration. Using an intensified charge-coupled device (ICCD), temporal evolution of the discharge between the two electrodes is investigated for the diffuse mode and the patterned mode, respectively. For the diffuse mode, the positive discharge is in a glow regime, and the negative discharge is in a Townsend discharge regime. For the patterned mode, the discharge always belongs to the Townsend discharge regime. Moreover, in the patterned mode, various patterns including the single loop, single loop with the surrounding corona, triple loops, and concentric loops with a central spot are observed on the water surface with the increasing positive peak-value of the applied voltage (Upp). Temporally resolved images of the loop-patterns are captured on the water surface. From the electrical measurements and the ICCD imaging, it is found that the loop pattern emerges after the discharge bridges the two electrodes. Then, it begins to evolve and finally degenerates with the decrease in the discharge current. The pattern does not disappear until the discharge quenches. Formation of the loop-patterns is attributed to the role of negative ions.

Anomalous Transport in High Beta Poloidal DIII-D Discharges

NASA Astrophysics Data System (ADS)

Pankin, A.; Garofalo, A.; Kritz, A.; Rafiq, T.; Weiland, J.

2016-10-01

Dominant instabilities that drive anomalous transport in high beta poloidal DIII-D discharges are investigated using the MMM7.1, and TGLF models in the predictive integrated modeling TRANSP code. The ion thermal transport is found to be strongly reduced in these discharges, but turbulence driven by the ITG modes along with the neoclassical transport still play a role in determining the ion temperature profiles. The electron thermal transport driven by the ETG modes impact the electron temperature profiles. The E × B flow shear is found to have a small effect in reducing the electron thermal transport. The Shafranov shift is found to strongly reduce the anomalous transport in the high beta poloidal DIII-D discharges. The reduction of Shafranov shift can destroy the ion internal transport barrier and can result in significantly lower core temperatures. The MMM7.1 model predicts electron and ion temperature profiles reasonably well, but it fails to accurately predict the properties of electron internal transport barrier, which indicates that the ETG model in MMM7.1 needs to be improved in the high beta poloidal operational regime. Research supported by the Office of Science, US DOE.

Discharge runaway in high power impulse magnetron sputtering of carbon: the effect of gas pressure, composition and target peak voltage

NASA Astrophysics Data System (ADS)

Vitelaru, Catalin; Aijaz, Asim; Constantina Parau, Anca; Kiss, Adrian Emil; Sobetkii, Arcadie; Kubart, Tomas

2018-04-01

Pressure and target voltage driven discharge runaway from low to high discharge current density regimes in high power impulse magnetron sputtering of carbon is investigated. The main purpose is to provide a meaningful insight of the discharge dynamics, with the ultimate goal to establish a correlation between discharge properties and process parameters to control the film growth. This is achieved by examining a wide range of pressures (2–20 mTorr) and target voltages (700–850 V) and measuring ion saturation current density at the substrate position. We show that the minimum plasma impedance is an important parameter identifying the discharge transition as well as establishing a stable operating condition. Using the formalism of generalized recycling model, we introduce a new parameter, ‘recycling ratio’, to quantify the process gas recycling for specific process conditions. The model takes into account the ion flux to the target, the amount of gas available, and the amount of gas required for sustaining the discharge. We show that this parameter describes the relation between the gas recycling and the discharge current density. As a test case, we discuss the pressure and voltage driven transitions by changing the gas composition when adding Ne into the discharge. We propose that standard Ar HiPIMS discharges operated with significant gas recycling do not require Ne to increase the carbon ionization.

Operation Regime Analysis of Conduction Cooled Cavities through Multi-Physics Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostin, R.; Kanareykin, A.; Kephart, R. D.

Euclid Techlabs in collaboration with Fermilab IARC (Batavia, IL) is developing industrial superconducting 10MeV electron linac [1, 2]. Cryocoolers are to be used for cooling instead of liquid helium bath to simplify the linac infrastructure [3]. The cavity linked to commercially available cryo-cooler cold head [4, 5] through highly conductive aluminium (AL) strips. However, this solution raises a problem of contact thermal resistance. This paper shows some results of Comsol multyphysics simulations of the cavity cooling by AL strips. Some insight was obtained on the acceptable range of contact resistance. Operation regimes were obtained at different accelerating gradients and cavitymore » temperatures. The results of simula-tion are presented and discussed.« less

Temporal changes in VOC discharge to surface water from a fractured rock aquifer during well installation and operation, Greenville, South Carolina

USGS Publications Warehouse

Vroblesky, D.A.; Robertson, J.F.

1996-01-01

Analysis of the vapor in passive vapor samplers retrieved from a streambed in fractured rock terrain implied that volatile organic carbon (VOC) discharge from ground water to surface water substantially increased following installation of a contaminant recovery well using air rotary drilling. The air rotary technique forced air into the aquifer near the stream. The injection produced an upward hydraulic gradient that appears to have transported water and contaminants from deeper parts of the aquifer through fractures into shallow parts of the aquifer. Once in the shallow flow regime, the contamination was transported to the stream, where it discharged during the next several weeks following well installation. After the recovery well was activated and began continuously pumping contaminated ground water to a treatment facility, the VOC concentrations in the stream bottom passive vapor samplers decreased to below detectable concentrations, suggesting that the withdrawal had captured the contaminated ground water that previously had discharged to the stream.

A New Look at the GEO and Near-GEO Regimes: Operations, Disposals, and Debris

NASA Technical Reports Server (NTRS)

Johnson, Nicholas

2011-01-01

Since 1963 more than 900 spacecraft and more than 200 launch vehicle upper stages have been inserted into the vicinity of the geosynchronous regime. Equally important, more than 300 spacecraft have been maneuvered into disposal orbits at mission termination to alleviate unnecessary congestion in the finite GEO region. However, the number of GEO satellites continues to grow, and evidence exists of a substantial small debris population. In addition, the operational modes of an increasing number of GEO spacecraft differ from those of their predecessors of several decades ago, including more frequent utilization of inclined and eccentric geosynchronous orbits. Consequently, the nature of the GEO regime and its immediate surroundings is evolving from well-known classical characteristics. This paper takes a fresh look at the GEO satellite population and the near- and far-term environmental implications of the region, including the effects of national and international debris mitigation measures.

Microwave Discharges

NASA Astrophysics Data System (ADS)

Marec, J.; Bloyet, E.; Chaker, M.; Leprince, P.; Nghiem, P.

Microwave discharges first appeared as unwanted and disturbing effects. However, beginning about the end of World War II, Professors Allis and Brown at the Massachusetts Institute of Technology started to investigate the physics of these discharges. During the next few years, many experimental and theoretical studies were undertaken. However, in the early 60's and for about 15 years, there were few studies of such discharges because of the theoretical difficulties encountered. Effectively, the impossibility of modeling microwave discharges prevented a good understanding of their behavior, and their future use did not appear promising. Recently there has been new interest in these discharges. The plasmas produced by microwave discharges find applications in areas such as: 1) spectroscopy (because of their low contamination), and 2) plasma chemistry. Another advantage of these discharges as compared to d.c. discharges is their ease of operation.

The New English Quality Assurance Regime

ERIC Educational Resources Information Center

Brown, Roger

2011-01-01

England is developing a new quality assurance regime that will come into effect in October 2011. A new funding regime will operate from the following year, together with new rules to ease the participation of private higher education providers. This article describes and analyses the new quality and funding regimes. It argues that the greater…

Enhanced focus steering abilities of multi-element therapeutic arrays operating in nonlinear regimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuldashev, P., E-mail: petr@acs366.phys.msu.ru; Ilyin, S.; Gavrilov, L.

2015-10-28

Steering abilities of a typical HIFU therapeutic array operated in linear and nonlinear regimes were compared using numerical simulation with the 3D Westervelt equation. The array included 256 elements of 1.2 MHz frequency and 6.6 mm diameter distributed in a quasi-random pattern over a spherical shell with a 130 mm aperture and a focal length of 120 mm. In the case of linear focusing, thermal effects are proportional to the intensity level and the criterion for safe array operation is that the intensity in the grating lobes should be less than 10% of the intensity in the main focus. Inmore » the case of nonlinear focusing, the heating effect is no longer proportional to intensity; therefore the heat deposition rate was chosen as the relevant metric, using the same 10% threshold for the secondary lobe in comparison with the focal maximum. When steering the focus, the same linearly predicted intensity level at the main focus was maintained by increasing the array power. Numerical simulations of the acoustic field were performed for nonlinear propagation both in water and in tissue. It was shown that for shock-forming conditions in the main focus, the steering range of safe electronic focusing is larger than that for linear propagation conditions. Nonlinear sonication regimes therefore can be used to enlarge tissue volumes that can be sonicated using electronic steering of the focus of HIFU arrays.« less

Parametric system identification of resonant micro/nanosystems operating in a nonlinear response regime

NASA Astrophysics Data System (ADS)

Sabater, A. B.; Rhoads, J. F.

2017-02-01

The parametric system identification of macroscale resonators operating in a nonlinear response regime can be a challenging research problem, but at the micro- and nanoscales, experimental constraints add additional complexities. For example, due to the small and noisy signals micro/nanoresonators produce, a lock-in amplifier is commonly used to characterize the amplitude and phase responses of the systems. While the lock-in enables detection, it also prohibits the use of established time-domain, multi-harmonic, and frequency-domain methods, which rely upon time-domain measurements. As such, the only methods that can be used for parametric system identification are those based on fitting experimental data to an approximate solution, typically derived via perturbation methods and/or Galerkin methods, of a reduced-order model. Thus, one could view the parametric system identification of micro/nanosystems operating in a nonlinear response regime as the amalgamation of four coupled sub-problems: nonparametric system identification, or proper experimental design and data acquisition; the generation of physically consistent reduced-order models; the calculation of accurate approximate responses; and the application of nonlinear least-squares parameter estimation. This work is focused on the theoretical foundations that underpin each of these sub-problems, as the methods used to address one sub-problem can strongly influence the results of another. To provide context, an electromagnetically transduced microresonator is used as an example. This example provides a concrete reference for the presented findings and conclusions.

Exploration of Gas Discharges with GaAs, GaP and ZnSe Electrodes Under Atmospheric Pressure

NASA Astrophysics Data System (ADS)

Kurt, H. Hilal

2018-03-01

This work reports on the electrical and optical characterization of the atmospheric pressure glow discharge regimes for different semiconductor electrodes made of GaAs, GaP and ZnSe. The discharge cell is driven by DC feeding voltages at a wide pressure range of 0.66-120 kPa in argon and air media for different interelectrode gaps. The discharge phenomena including different stages of discharges such as glow and Townsend breakdown have been examined. In addition, the infrared sensitivities of the semiconducting materials are evaluated in the micro-discharge cell and discharge light emission measurements have been performed. The qualities of the semiconducting electrode samples can be determined by seeking the homogeneity of the discharge light emission for the optoelectronic device applications. Operation of optical devices under atmospheric pressures gives certain advantages for manufacturing of the devices including the material processing and surface treatment procedures. Besides, finite element analyses of the overall experimental system have been performed for the abovementioned semiconductors. The electron densities and potential patterns have been determined on the discharge cell plane between the electrodes. The findings have proven that the electron densities along the plasma cell depend on both the semiconductor type and plasma parameters.

Beyond feast and famine: Selecting a PHA accumulating photosynthetic mixed culture in a permanent feast regime.

PubMed

Fradinho, J C; Reis, M A M; Oehmen, A

2016-11-15

Currently, the feast and famine (FF) regime is the most widely applied strategy to select for polyhydroxyalkanoate (PHA) accumulating organisms in PHA production systems with mixed microbial cultures. As an alternative to the FF regime, this work studied the possibility of utilizing a permanent feast regime as a new operational strategy to select for PHA accumulating photosynthetic mixed cultures (PMCs). The PMC was selected in an illuminated environment and acetate was constantly present in the mixed liquor to guarantee a feast regime. During steady-state operation, the culture presented low PHA accumulation levels, likely due to low light availability, which resulted in most of the acetate being used for biomass growth (Y x/s of 0.64 ± 0.18 Cmol X/Cmol Acet). To confirm the light limitation on the PMC, SBR tests were conducted with higher light availability, at similar levels as would be expectable from natural sunlight. In this case, the Y x/s reduced to 0.11 ± 0.01 Cmol X/Cmol Acet and the culture presented a PHB production yield on acetate of 0.67 ± 0.01 Cmol PHB/Cmol Acet, leading to a maximum PHB content of 60%. Unlike other studied PMCs, the PMC was capable of simultaneous growth and PHB accumulation continuously throughout the cycle. Thus far, 60% PHA content is the maximum value ever reported for a PMC, a result that prospects the utilization of feast regimes as an alternative strategy for the selection of PHA accumulating PMCs. Furthermore, the PMC also presented high phosphate removal rates, delivering an effluent that complies with phosphate discharge limits. The advantages of selecting PMCs under a permanent feast regime are that no aeration inputs are required; it allows higher PHA contents and phosphate removal rates in comparison to FF-operated PMC systems; and it represents a novel means of integrating wastewater treatment with resource recovery in the form of PHA. Copyright © 2016 Elsevier Ltd. All rights reserved.

High energy bursts from a solid state laser operated in the heat capacity limited regime

DOEpatents

Albrecht, G.; George, E.V.; Krupke, W.F.; Sooy, W.; Sutton, S.B.

1996-06-11

High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes. 5 figs.

High energy bursts from a solid state laser operated in the heat capacity limited regime

DOEpatents

Albrecht, Georg; George, E. Victor; Krupke, William F.; Sooy, Walter; Sutton, Steven B.

1996-01-01

High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes.

Optimization of DIII-D discharges to avoid AE destabilization

NASA Astrophysics Data System (ADS)

Varela, Jacobo; Spong, Donald; Garcia, Luis; Huang, Juan; Murakami, Masanori

2017-10-01

The aim of the study is to analyze the stability of Alfven Eigenmodes (AE) perturbed by energetic particles (EP) during DIII-D operation. We identify the optimal NBI operational regimes that avoid or minimize the negative effects of AE on the device performance. We use the reduced MHD equations to describe the linear evolution of the poloidal flux and the toroidal component of the vorticity in a full 3D system, coupled with equations of density and parallel velocity moments for the energetic particles, including the effect of the acoustic modes. We add the Landau damping and resonant destabilization effects using a closure relation. We perform parametric studies of the MHD and AE stability, taking into account the experimental profiles of the thermal plasma and EP, also using a range of values of the energetic particles β, density and velocity as well the effect of the toroidal couplings. We reproduce the AE activity observed in high poloidal β discharge at the pedestal and reverse shear discharges. This material based on work is supported both by the U.S. Department of Energy, Office of Science, under Contract DE-AC05-00OR22725 with UT-Battelle, LLC. Research sponsored in part by the Ministerio de Economia y Competitividad of Spain under the project.

Recurrent vaginal discharge in children.

PubMed

McGreal, Sharon; Wood, Paul

2013-08-01

Childhood vaginal discharge remains a frequent reason for referral from primary to secondary care. The Pediatric and Adolescent Gynecology (PAG) service at Kettering General Hospital was established in 1993 and provides a specialized service that meets the needs of children with gynaecological conditions. To investigate recurrent vaginal discharge noting symptomatology, defining pathogens, common and rarer causes, exploring management regimes, and any changes in practice over time. Retrospective review spanning 15 years identifying prepubertal children attending the outpatient PAG clinic with recurrent vaginal discharge. We reviewed the medical notes individually. 110 patients were identified; 85% were referred from primary care. The age distribution was bimodal at four and eight years. Thirty-five percent of our patients were discharged after the initial consultation. The commonest cause of discharge was vulvovaginitis (82%). Other important causes included suspected sexual abuse (5%), foreign body (3%), labial adhesions (3%), vaginal agenesis (2%). 35% of patients were admitted for vaginoscopy. Vaginal discharge is the most common gynecological symptom in prepubertal girls and can cause repeated clinical episodes. Vulvovaginitis is the most common cause and often responds to simple hygiene measures. Awareness of the less common causes of vaginal discharge is essential. Copyright © 2013 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

20 CFR 726.207 - Discharge by the carrier of obligations and duties of operator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Discharge by the carrier of obligations and duties of operator. 726.207 Section 726.207 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION, DEPARTMENT OF LABOR FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED BLACK LUNG BENEFITS...

H2OTSTUF: Appropriate Operating Regimes for Magnetohydrodynamic Augmentation

NASA Technical Reports Server (NTRS)

Jones, Jonathan E.; Hawk, Clark W.

1998-01-01

A trade study of magnetohydrodynamic (MHD) augmented propulsion reveals a unique operating regime at lower thrust levels. Substantial mass savings are realized over conventional chemical, solar, and electrical propulsion concepts when MHD augmentation is used to obtain optimal I(sub sp). However, trip times for the most conservative estimates of power plant specific impulse and accelerator efficiency may be prohibitively long. Quasi-one-dimensional calculations show that a solar or nuclear thermal system augmented by MHD can provide competitive performance while utilizing a diverse range of propellants including water, which is available from the Space Shuttle, the Moon, asteroids, and various moons and planets within our solar system. The use of in-situ propellants will reduce costs of space operations as well as enable human exploration of our Solar System. The following conclusions can be drawn from the results of the mission trade study: (1) There exists a maximum thrust or mass flow rate above which MHD augmentation increases the initial mass in low earth orbit (LEO); (2) Mass saving of over 50% can be realized for unique combination of solar/MHD systems; (3) Trip times for systems utilizing current power supply technology may be prohibitively long. Theoretical predictions of MHD performance for in space propulsion systems show that improved efficiencies can reduce trip times to acceptable levels; (4) Long trip times indicative of low thrust systems can be shortened by an increase in the MHD accelerator efficiency or a decrease in the specific mass of the power supply and power processing unit; and (5) As for all propulsion concepts, missions with larger (Delta)v's benefit more from the increased specific impulse resulting from MHD augmentation. Using a quasi-one-dimensional analysis, the required operating conditions for a MHD accelerator to reach acceptable efficiencies are outlined. This analysis shows that substantial non-equilibrium ionization is

Infrared gas phase study on plasma-polymer interactions in high-current diffuse dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Liu, Y.; Welzel, S.; Starostin, S. A.; van de Sanden, M. C. M.; Engeln, R.; de Vries, H. W.

2017-06-01

A roll-to-roll high-current diffuse dielectric barrier discharge at atmospheric pressure was operated in air and Ar/N2/O2 gas mixtures. The exhaust gas from the discharge was studied using a high-resolution Fourier-transform infrared spectrometer in the range from 3000 to 750 cm-1 to unravel the plasma-polymer interactions. The absorption features of HxNyOz, COx, and HCOOH (formic acid) were identified, and the relative densities were deduced by fitting the absorption bands of the detected molecules. Strong interactions between plasma and polymer (Polyethylene-2,6-naphthalate, or PEN) in precursor-free oxygen-containing gas mixtures were observed as evidenced by a high COx production. The presence of HCOOH in the gas effluent, formed through plasma-chemical synthesis of COx, turns out to be a sensitive indicator for etching. By adding tetraethylorthosilicate precursor in the plasma, dramatic changes in the COx production were measured, and two distinct deposition regimes were identified. At high precursor flows, a good agreement with the precursor combustion and the COx production was observed, whereas at low precursor flows an etching-deposition regime transpires, and the COx production is dominated by polymer etching.

Operational Constraints on Hydropeaking and its Effects on the Hydrologic and Thermal Regime of a River in Central Chile

NASA Astrophysics Data System (ADS)

Olivares, M. A.; Guzman, C.; Rossel, V.; De La Fuente, A.

2013-12-01

Hydropower accounts for about 44% of installed capacity in Chile's Central Interconnected System, which serves most of the Chilean population. Hydropower reservoir projects can affect ecosystems by changing the hydrologic regime and water quality. Given its volumen regulation capacity, low operation costs and fast response to demand fluctuations, reservoir hydropower plants commonly operate on a load-following or hydropeaking scheme. This short-term operational pattern produces alterations in the hydrologic regime downstream the reservoir. In the case of thermally stratified reservoirs, peaking operations can affect the thermal structure of the reservoir, as well as the thermal regime downstream. In this study, we assessed the subdaily hydrologic and thermal alteration donwstream of Rapel reservoir in Central Chile for alternative operational scenarios, including a base case and several scenarios involving minimum instream flow (Qmin) and maximum hourly ramping rates (ΔQmax). Scenarios were simulated for the stratification season of summer 2009-2012 in a grid-wide short-term economic dispatch model which prescribes hourly power production by every power plant on a weekly horizon. Power time series are then translated into time series of turbined flows at each hydropower plants. Indicators of subdaily hydrologic alteration (SDHA) were computed for every scenario. Additionally, turbined flows were used as input data for a three-dimensional hydrodynamic model (CWR-ELCOM) of the reservoir which simulated the vertical temperature profile in the reservoir and the outflow temperature. For the time series of outflow temperatures we computed several indicators of subdaily thermal alteration (SDTA). Operational constraints reduce the values of both SDHA and SDTA indicators with respect to the base case. When constraints are applied separately, the indicators of SDHA decrease as each type of constraint (Qmin or ΔQmax) becomes more stringent. However, ramping rate

Application of Temperature Index Model to Assess the Future Hydrological Regime of the Glacierized Catchments in Nepal.

NASA Astrophysics Data System (ADS)

Kayastha, R.; Kayastha, R. B.

2017-12-01

Unavailability of hydro meteorological data in the Himalayan regions is challenging on understanding the flow regimes. Temperature index model is simple yet the powerful glacio-hydrological model to simulate the discharge in the glacierized basin. Modified Positive Degree Day (MPDD) Model Version 2.0 is a grid-ded based semi distributed model with baseflow module is a robust melt modelling tools to estimate the discharge. MPDD model uses temperature and precipitation as a forcing datasets to simulate the discharge and also to obtain the snowmelt, icemelt, rain and baseflow contribution on total discharge. In this study two glacierized, Marsyangdi and Langtang catchment were investigated for the future hydrological regimes. Marsyangdi encompasses an area of 4026.19 sq. km with 20% glaciated area, whereas Langtang catchment with area of 354.64 sq. km with 36% glaciated area is studied to examine for the future climatic scenarios. The model simulates discharge well for the observed period; (1992-1998) in Marsyangdi and from (2007-2013) in Langtang catchment. The Nash-Sutcliffe Efficiency (NSE) for the both catchment were above 0.75 with the volume difference less than - 8 %. The snow and ice melts contribution in Marsyangdi were 4.7% and 10.2% whereas in Langtang the contribution is 15.3% and 23.4%, respectively. Rain contribution ( 40%) is higher than the baseflow contribution in total discharge in both basins. The future river discharge is also predicted using the future climate data from the regional climate models (RCMs) of CORDEX South Asia experiments for the medium stabilization scenario RCP4.5 and very high radiative forcing scenario RCP8.5 after bias correction. The projected future discharge of both catchment shows slightly increase in both scenarios with increase of snow and ice melt contribution on discharge. The result generated from the model can be utilized to understand the future hydrological regimes of the glacierized catchment also the impact of

Pain after discharge following head and neck surgery in children.

PubMed

Wilson, Caroline A; Sommerfield, David; Drake-Brockman, Thomas F E; von Bieberstein, Lita; Ramgolam, Anoop; von Ungern-Sternberg, Britta S

2016-10-01

It is well established that children experience significant pain for a considerable period following adenotonsillectomy. Less is known, however, about pain following other common head and neck operations. The aim of this study was to describe the severity and duration of postoperative pain experienced by children undergoing elective head and neck procedures (primary outcomes). Behavioral disturbance, nausea and vomiting, parental satisfaction, and medical reattendance rates were also measured (secondary outcomes). Parents of children (0-18 years) undergoing common head and neck operations were invited to participate. Pain scores on the day of surgery and each day post discharge were collected via multiple telephone interviews. Data collected included pain levels, analgesia prescribed and given, behavioral disturbance rates, and nausea and vomiting scores. Follow-up was continued until pain resolved. Two hundred and fifty-one patients were analyzed (50 adenoidectomy, 51 adenotonsillectomy, 19 myringoplasty, 52 myringotomy, 43 strabismus, and 36 tongue tie divisions). On the day of surgery myringoplasty, strabismus surgery, and adenotonsillectomy patients on average had moderate pain, whereas adenoidectomy, tongue tie, and myringotomy patients had mild pain. Adenotonsillectomy patients continued to have moderate pain for several days with pain lasting on average 9 days. From day 1 postoperatively mild pain was experienced in the other surgical groups with the average duration of pain varying from 1 to 3 days depending on the surgery performed. Frequency of behavioral issues closely followed pain scores for each group. Analgesic prescribing and regimes at home varied widely, both within and between the different surgical groups. Rates of nausea and vomiting following discharge were low in all groups. The overall unplanned medical reattendance rate was 16%. Adenotonsillectomy patients represent the biggest challenge in postoperative pain management of the head and neck

Plasma dynamics in a packed bed dielectric barrier discharge (DBD) operated in helium

NASA Astrophysics Data System (ADS)

Mujahid, Zaka-ul-Islam; Hala, Ahmed

2018-03-01

Packed bed dielectric barrier discharges (DBDs) are very promising for several applications including remediation of environmental pollutants and greenhouse gas conversion. In this work, we have investigated the space and time-resolved emission from a packed bed DBD operated in helium, to understand the plasma dynamics. We have chosen a simple planar DBD arrangement with a patterned dielectric, which mimics the spherical boundaries between the dielectric pellets and allows the optical access to the plasma. The results show that plasma is sustained in a packed bed DBD by three mechanisms: filamentary discharge in the void (between the center of dielectric structures and the opposite electrode), microdischarges at the contact points and surface ionization waves over the dielectric surface. It is observed that for most of the duration plasma is generated at the contact points between the dielectric structures.

Experimental investigations on characteristics of stable water electrospray in air without discharge

NASA Astrophysics Data System (ADS)

Park, Inyong; Hong, Won Seok; Kim, Sang Bok; Kim, Sang Soo

2017-06-01

An experimental study was conducted to resolve previous conflicting results on water electrospray in air at atmospheric pressure. Using a small flow rate relative to that used in previous studies and a small nonmetallic nozzle, we observed stable electrospray of water in air without discharge and distinguished three distinct operating regimes for applied voltage and flow rate. The well-known cone-jet mode was observed and the general scaling law of the generated droplet size in the cone-jet mode was confirmed by direct visualization of the meniscus, jet, and generated droplets. We also observed and analyzed whipping motion in the electrified water jet.

Characterization of millimetre magnitude atmospheric pressure streamer discharge in pin-to-plane dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Xu, S. J.; Zhang, Y. H.; Yu, Z.; Yao, J.; Zhang, Z. T.

2013-03-01

The streamer regime of pin-to-plane dielectric barrier discharge in air was studied by means of fast photography, electrical measurement and photoelectricity. The fast photographs of positive streamer were obtained by CCD camera with micro lens. The exposure time is one microseconds. The images illustrate that the streamer is non-axisymmetric because of some random factors, such as surface charge position, space charge distribution, gas liquidity and so on. In fact, the streamer propagates along bend discharge channel. The bending degree increases with the electric field strengthen. By surveying a mass of images, the diameter of streamer, height of surface charge effect and scope of surface charge was estimate used to describe the shape of streamer.

Sediment regime constraints on river restoration - An example from the lower Missouri river

USGS Publications Warehouse

Jacobson, R.B.; Blevins, D.W.; Bitner, C.J.

2009-01-01

Dammed rivers are subject to changes in their flow, water-quality, and sediment regimes. Each of these changes may contribute to diminished aquatic habitat quality and quantity. Of the three factors, an altered sediment regime is a particularly unyielding challenge on many dammed rivers. The magnitude of the challenge is illustrated on the Lower Missouri River, where the largest water storage system in North America has decreased the downriver suspended-sediment load to 0.2%–17% of pre-dam loads. In response to the altered sediment regime, the Lower Missouri River channel has incised as much as 3.5 m just downstream of Gavins Point Dam, although the bed has been stable to slightly aggrading at other locations farther downstream. Effects of channel engineering and commercial dredging are superimposed on the broad-scale adjustments to the altered sediment regime.The altered sediment regime and geomorphic adjustments constrain restoration and management opportunities. Incision and aggradation limit some objectives of flow-regime management: In incising river segments, ecologically desirable reconnection of the floodplain requires discharges that are beyond operational limits, whereas in aggrading river segments, small spring pulses may inundate or saturate low-lying farmlands. Lack of sediment in the incising river segment downstream of Gavins Point Dam also limits sustainable restoration of sand-bar habitat for bird species listed under the Endangered Species Act. Creation of new shallow-water habitat for native fishes involves taking sediment out of floodplain storage and reintroducing most or all of it to the river, raising concerns about increased sediment, nutrient, and contaminant loads. Calculations indicate that effects of individual restoration projects are small relative to background loads, but cumulative effects may depend on sequence and locations of projects. An understanding of current and historical sediment fluxes, and how they vary along the river

Neutral gas rotation in magnetron discharge

NASA Astrophysics Data System (ADS)

Pal, A. F.; Ryabinkin, A. N.; Serov, A. O.; Filippov, A. V.

2014-12-01

We have experimentally established the existence and determined the velocity of motion of the neutral component of plasma in a planar magnetron discharge, which takes place in the direction of drift of the charged plasma component in crossed electric and magnetic ( E × B) fields. For this purpose, we have studied the propagation of a small gaseous additive over the plasma ring of dc magnetron discharge in the diffusion regime. The obtained temporal dependences of the intensity of atomic emission spectra of the additive in various regions of the plasma ring are compared to the results of numerical solution of the diffusion equation for the experimental conditions studied.

Dynamics of laser-guided alternating current high voltage discharges

NASA Astrophysics Data System (ADS)

Daigle, J.-F.; Théberge, F.; Lassonde, P.; Kieffer, J.-C.; Fujii, T.; Fortin, J.; Châteauneuf, M.; Dubois, J.

2013-10-01

The dynamics of laser-guided alternating current high voltage discharges are characterized using a streak camera. Laser filaments were used to trigger and guide the discharges produced by a commercial Tesla coil. The streaking images revealed that the dynamics of the guided alternating current high voltage corona are different from that of a direct current source. The measured effective corona velocity and the absence of leader streamers confirmed that it evolves in a pure leader regime.

Resistive Wall Modes Identification and Control in RFX-mod low qedge tokamak discharges

NASA Astrophysics Data System (ADS)

Baruzzo, Matteo; Bolzonella, Tommaso; Cavazzana, Roberto; Marchiori, Giuseppe; Marrelli, Lionello; Martin, Piero; Paccagnella, Roberto; Piovesan, Paolo; Piron, Lidia; Soppelsa, Anton; Zanca, Paolo; in, Yongkyoon; Liu, Yueqiang; Okabayashi, Michio; Takechi, Manabu; Villone, Fabio

2011-10-01

In this work the MHD stability of RFX mode tokamak discharges with qedge < 3 will be studied. The target plasma scenario is characterized by a plasma current 100kA operation in this regime is limited by the onset of a slowly rotating m = 2 n = 1 kink mode, which eventually locks to the wall and induces a disruption. The mode growth rates have been characterized with regard to the main plasma parameters and have been compared with predictions by the linear MHD code MARS-F, and the 3D finite elements code CARMA, permitting a full Resistive Wall Mode identification. The stability of the mode in the vicinity of the unstable operational space has been studied using MHD spectroscopy on the (2/1) mode. A good discharge behaviour with qedge < 2 has been routinely obtained using the RFX-mod MHD active control system, which is capable of fully stabilizing the mode acting on the radial magnetic field at the plasma edge.

Low Pressure Experimental Simulation of Electrical Discharges Above and Inside a Cloud

NASA Technical Reports Server (NTRS)

Jarzembski, Maurice A.; Srivastava, Vandana

1996-01-01

A low pressure laboratory experiment to generate sporadic electrical discharges in either a particulate dielectric or air, representing a competing path of preferred electrical breakdown, was investigated. At high pressures, discharges occurred inside the dielectric particulate; at low pressures, discharges occurred outside the dielectric particulate; at a transition pressure regime, which depends on conductivity of the dielectric particulate, discharges were simultaneously generated in both particulate dielectric and air. Unique use of a particulate dielectric was critical for sporadic discharges at lower pressures which were not identical in character to discharges without the particulate dielectric. Application of these experimental results to the field of atmospheric electricity and simulation of the above-cloud type discharges that have recently been documented, called jets and sprites, are discussed.

Direct electron-impact mechanism of excitation of mercury monobromide in a double-pulse dielectric-barrier-discharge HgBr lamp

NASA Astrophysics Data System (ADS)

Datsyuk, V. V.; Izmailov, I. A.; Naumov, V. V.; Kochelap, V. A.

2016-08-01

In a nonequlibrium plasma of a gas-discharge HgBr lamp, the terminal electronic state of the HgBr(B-X) radiative transition with a peak wavelength of 502 nm remains populated for a relatively long time and is repeatedly excited to the B state in collisions with plasma electrons. This transfer of the HgBr molecules from the ground state X to the excited state B is the main mechanism of formation of the light-emitting molecules especially when the lamp is excited by double current pulses. According to our simulations, due to the electron-induced transitions between HgBr(X) and HgBr(B), the output characteristics of the DBD lamp operating in a double-pulse regime are better than those of the lamp operating in a single-pulse regime. In the considered case, the peak power is calculated to increase by a factor of about 2 and the lamp efficiency increases by about 50%.

Stability of DIII-D high-performance, negative central shear discharges

DOE PAGES

Hanson, Jeremy M.; Berkery, John W.; Bialek, James M.; ...

2017-03-20

Tokamak plasma experiments on the DIII-D device demonstrate high-performance, negative central shear (NCS) equilibria with enhanced stability when the minimum safety factor q min exceeds 2, qualitatively confirming theoretical predictions of favorable stability in the NCS regime. The discharges exhibit good confinement with an L-mode enhancement factor H 89 = 2.5, and are ultimately limited by the ideal-wall external kink stability boundary as predicted by ideal MHD theory, as long as tearing mode (TM) locking events, resistive wall modes (RWMs), and internal kink modes are properly avoided or controlled. Although the discharges exhibit rotating TMs, locking events are avoided asmore » long as a threshold minimum safety factor value q min > 2 is maintained. Fast timescale magnetic feedback control ameliorates RWM activity, expanding the stable operating space and allowing access to β N values approaching the ideal-wall limit. Quickly growing and rotating instabilities consistent with internal kink mode dynamics are encountered when the ideal-wall limit is reached. The RWM events largely occur between the no- and ideal-wall pressure limits predicted by ideal MHD. However, evaluating kinetic contributions to the RWM dispersion relation results in a prediction of passive stability in this regime due to high plasma rotation. In addition, the ideal MHD stability analysis predicts that the ideal-wall limit can be further increased to β N > 4 by broadening the current profile. Furthermore, this path toward improved stability has the potential advantage of being compatible with the bootstrap-dominated equilibria envisioned for advanced tokamak (AT) fusion reactors.« less

Stability of DIII-D high-performance, negative central shear discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, Jeremy M.; Berkery, John W.; Bialek, James M.

Tokamak plasma experiments on the DIII-D device demonstrate high-performance, negative central shear (NCS) equilibria with enhanced stability when the minimum safety factor q min exceeds 2, qualitatively confirming theoretical predictions of favorable stability in the NCS regime. The discharges exhibit good confinement with an L-mode enhancement factor H 89 = 2.5, and are ultimately limited by the ideal-wall external kink stability boundary as predicted by ideal MHD theory, as long as tearing mode (TM) locking events, resistive wall modes (RWMs), and internal kink modes are properly avoided or controlled. Although the discharges exhibit rotating TMs, locking events are avoided asmore » long as a threshold minimum safety factor value q min > 2 is maintained. Fast timescale magnetic feedback control ameliorates RWM activity, expanding the stable operating space and allowing access to β N values approaching the ideal-wall limit. Quickly growing and rotating instabilities consistent with internal kink mode dynamics are encountered when the ideal-wall limit is reached. The RWM events largely occur between the no- and ideal-wall pressure limits predicted by ideal MHD. However, evaluating kinetic contributions to the RWM dispersion relation results in a prediction of passive stability in this regime due to high plasma rotation. In addition, the ideal MHD stability analysis predicts that the ideal-wall limit can be further increased to β N > 4 by broadening the current profile. Furthermore, this path toward improved stability has the potential advantage of being compatible with the bootstrap-dominated equilibria envisioned for advanced tokamak (AT) fusion reactors.« less

Flow regimes in a T-mixer operating with a binary mixture

NASA Astrophysics Data System (ADS)

Camarri, Simone; Siconolfi, Lorenzo; Galletti, Chiara; Salvetti, Maria Vittoria

2015-11-01

Efficient mixing in small volumes is a key target in many processes. Among the most common micro-devices, passive T-shaped micro-mixers are widely used. For this reason, T-mixers have been studied in the literature and its working flow regimes have been identified. However, in most of the available theoretical studies it is assumed that only one working fluid is used, i.e. that the same fluid at the same thermodynamic conditions is entering the two inlet conduits of the mixer. Conversely, the practical use of micro-devices often involves the mixing of two different fluids or of the same fluid at different thermodynamic conditions. In this case flow regimes significantly different than those observed for a single working fluid may occur. The present work aims at investigating the flow regimes in a T-mixers when water at two different temperatures, i.e. having different viscosity and density, is entering the mixer. The effect of the temperature difference on the flow regimes in a 3D T-mixer is investigated by DNS and stability analysis and the results are compared to the case in which a single working fluid is employed.

Analysis of thermionic bare tether operation regimes in passive mode

NASA Astrophysics Data System (ADS)

Sanmartín, J. R.; Chen, Xin; Sánchez-Arriaga, G.

2017-01-01

A thermionic bare tether (TBT) is a long conductor coated with a low work-function material. In drag mode, a tether segment extending from anodic end A to a zero-bias point B, with the standard Orbital-motion-limited current collection, is followed by a complex cathodic segment. In general, as bias becomes more negative in moving from B to cathodic end C, one first finds space-charge-limited (SCL) emission covering up to some intermediate point B*, then full Richardson-Dushman (RD) emission reaching from B* to end C. An approximate analytical study, which combines the current and voltage profile equations with results from asymptotic studies of the Vlasov-Poisson system for emissive probes, is carried out to determine the parameter domain covering two limit regimes, which are effectively controlled by just two dimensionless parameters involving ambient plasma and TBT material properties. In one such limit regime, no point B* is reached and thus no full RD emission develops. In an opposite regime, SCL segment BB* is too short to contribute significantly to the current balance.

Quasi-perpetual discharge behaviour in p-type Ge-air batteries.

PubMed

Ocon, Joey D; Kim, Jin Won; Abrenica, Graniel Harne A; Lee, Jae Kwang; Lee, Jaeyoung

2014-11-07

Metal-air batteries continue to become attractive energy storage and conversion systems due to their high energy and power densities, safer chemistries, and economic viability. Semiconductor-air batteries - a term we first define here as metal-air batteries that use semiconductor anodes such as silicon (Si) and germanium (Ge) - have been introduced in recent years as new high-energy battery chemistries. In this paper, we describe the excellent doping-dependent discharge kinetics of p-type Ge anodes in a semiconductor-air cell employing a gelled KOH electrolyte. Owing to its Fermi level, n-type Ge is expected to have lower redox potential and better electronic conductivity, which could potentially lead to a higher operating voltage and better discharge kinetics. Nonetheless, discharge measurements demonstrated that this prediction is only valid at the low current regime and breaks down at the high current density region. The p-type Ge behaves extremely better at elevated currents, evident from the higher voltage, more power available, and larger practical energy density from a very long discharge time, possibly arising from the high overpotential for surface passivation. A primary semiconductor-air battery, powered by a flat p-type Ge as a multi-electron anode, exhibited an unprecedented full discharge capacity of 1302.5 mA h gGe(-1) (88% anode utilization efficiency), the highest among semiconductor-air cells, notably better than new metal-air cells with three-dimensional and nanostructured anodes, and at least two folds higher than commercial Zn-air and Al-air cells. We therefore suggest that this study be extended to doped-Si anodes, in order to pave the way for a deeper understanding on the discharge phenomena in alkaline metal-air conversion cells with semiconductor anodes for specific niche applications in the future.

Pre-"peak water" time in the southwest Yukon: when cryospheric changes trigger hydrological regime shifts

NASA Astrophysics Data System (ADS)

Baraer, M.; Chesnokova, A.; Huh, K. I.; Laperriere-Robillard, T.

2017-12-01

Saint-Elias Mountains host numerous cryospheric systems such as glaciers, seasonal and perennial snow cover, permafrost, aufeis, and different forms of buried ice. Those systems are very sensitive to climate changes and exhibit ongoing reduction in extent and/or changes in formation/ablation times. Because they highly influence the hydrological regimes of rivers, cryospheric changes raise concerns about consequences for regional water resources and ecosystems. The present study combines historical data analysis and hydrological modeling in order to estimate how cryospheric changes impact hydrological regimes at eight watersheds of different glacier cover (0- 30%) in the southwest Yukon. Methods combine traditional hydrograph analysis techniques and more advance techniques such as Fast Fourier Transform filters used to isolate significant trends in discharge properties from noise or climatic oscillations. Measured trends in discharge variables are connected to cryospheric changes by using a water balance / peak water model (Baraer et al., 2012), here adapted to the main cryospheric systems that characterize the southwest Yukon.Results show three distinct hydrological regimes for (1) non glacierized, (2) glacierized, and (3) major lakes hosting catchments. The studied glacierized catchments have not passed the "peak water" yet and still exhibit increases in yearly and late summer discharges and a decrease in runoff variability. All watersheds show an increase in winter discharge and a snowmelt-driven shift of yearly peak discharge toward earlier in the season. The study suggests that, in a couple of decades, water resources and dependent ecosystems will face the combined effects of (A) a shift in the contribution trend from declining perennial cryospheric systems and (B) continuing alteration of the contribution from the seasonal cryospheric systems.

Overview of Initial NSTX-U Experimental Operations

NASA Astrophysics Data System (ADS)

Battaglia, Devon; the NSTX-U Team

2016-10-01

Initial operation of the National Spherical Torus Experiment Upgrade (NSTX-U) has satisfied a number of commissioning milestones, including demonstration of discharges that exceed the field and pulse length of NSTX. ELMy H-mode operation at the no-wall βN limit is obtained with Boronized wall conditioning. Peak H-mode parameters include: Ip = 1 MA, BT0 = 0.63 T, WMHD = 330 kJ, βN = 4, βN/li = 6, κ = 2.3, τE , tot >50 ms. Access to high-performance H-mode scenarios with long MHD-quiescent periods is enabled by the resilient timing of the L-H transition via feedback control of the diverting time and shape, and correction of the dominant n =1 error fields during the Ip ramp. Stationary L-mode discharges have been realized up to 1 MA with 2 s discharges achieved at Ip = 650 kA. The long-pulse L-mode discharges enabled by the new central solenoid supported initial experiments on error field measurements and correction, plasma shape control, controlled discharge ramp-down, L-mode transport and fast ion physics. Increased off-axis current drive and reduction of fast ion instabilities has been observed with the new, more tangential neutral beamline. The initial results support that access to increased field, current and heating at low-aspect-ratio expands the regimes available to develop scenarios, diagnostics and predictive models that inform the design and optimization of future burning plasma tokamak devices, including ITER. Work Supported by U.S. DOE Contract No. DE-AC02-09CH11466.

Progress Toward Steady State Tokamak Operation Exploiting the high bootstrap current fraction regime

NASA Astrophysics Data System (ADS)

Ren, Q.

2015-11-01

Recent DIII-D experiments have advanced the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Fully noninductive plasmas with extremely high values of the poloidal beta, βp >= 4 , have been sustained at βT >= 2 % for long durations with excellent energy confinement quality (H98y,2 >= 1 . 5) and internal transport barriers (ITBs) generated at large minor radius (>= 0 . 6) in all channels (Te, Ti, ne, VTf). Large bootstrap fraction (fBS ~ 80 %) has been obtained with high βp. ITBs have been shown to be compatible with steady state operation. Because of the unusually large ITB radius, normalized pressure is not limited to low βN values by internal ITB-driven modes. βN up to ~4.3 has been obtained by optimizing the plasma-wall distance. The scenario is robust against several variations, including replacing some on-axis with off-axis neutral beam injection (NBI), adding electron cyclotron (EC) heating, and reducing the NBI torque by a factor of 2. This latter observation is particularly promising for extension of the scenario to EAST, where maximum power is obtained with balanced NBI injection, and to a reactor, expected to have low rotation. However, modeling of this regime has provided new challenges to state-of-the-art modeling capabilities: quasilinear models can dramatically underpredict the electron transport, and the Sauter bootstrap current can be insufficient. The analysis shows first-principle NEO is in good agreement with experiments for the bootstrap current calculation and ETG modes with a larger saturated amplitude or EM modes may provide the missing electron transport. Work supported in part by the US DOE under DE-FC02-04ER54698, DE-AC52-07NA

Potential Industrial Applications of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) Operating in Ambient Air

NASA Astrophysics Data System (ADS)

Reece Roth, J.

2004-11-01

The majority of industrial plasma processing with glow discharges has been conducted at pressures below 10 torr. This tends to limit applications to high value workpieces as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharge plasmas would play a much larger industrial role if they could be generated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), developed at the University of Tennessee's Plasma Sciences Laboratory, is a non-thermal RF plasma operating on displacement currents with the time-resolved characteristics of a classical low pressure DC normal glow discharge. As a glow discharge, the OAUGDP operates with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum [1, 2]. Several interdisciplinary teams have investigated potential applications of the OAUGDP. These teams included collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC), and the Departments of Electrical and Computer Engineering, Microbiology, and Food Science and Technology, as well as the NASA Langley Research Center. The potential applications of the OAUGDP have all been at one atmosphere and room temperature, using air as the working gas. These applications include sterilizing medical and dental equipment; sterilizable air filters to deal with the "sick building syndrome"; removal of soot from Diesel engine exhaust; subsonic plasma aerodynamic effects, including flow re-attachment to airfoils and boundary layer modification; electrohydrodynamic (EDH) flow control of working gases; increasing the surface energy of materials; improving the adhesion of paints and electroplated layers: improving the wettability and wickability of fabrics; stripping of photoresist; and plasma deposition and directional etching of potential microelectronic relevance. [1] J. R. Roth, Industrial Plasma Engineering

Readiness for hospital discharge: A concept analysis.

PubMed

Galvin, Eileen Catherine; Wills, Teresa; Coffey, Alice

2017-11-01

To report on an analysis on the concept of 'readiness for hospital discharge'. No uniform operational definition of 'readiness for hospital discharge' exists in the literature; therefore, a concept analysis is required to clarify the concept and identify an up-to-date understanding of readiness for hospital discharge. Clarity of the concept will identify all uses of the concept; provide conceptual clarity, an operational definition and direction for further research. Literature review and concept analysis. A review of literature was conducted in 2016. Databases searched were: Academic Search Complete, CINAHL Plus with Full Text, PsycARTICLES, Psychology and Behavioural Sciences Collection, PsycINFO, Social Sciences Full Text (H.W. Wilson) and SocINDEX with Full Text. No date limits were applied. Identification of the attributes, antecedents and consequences of readiness for hospital discharge led to an operational definition of the concept. The following attributes belonging to 'readiness for hospital discharge' were extracted from the literature: physical stability, adequate support, psychological ability, and adequate information and knowledge. This analysis contributes to the advancement of knowledge in the area of hospital discharge, by proposing an operational definition of readiness for hospital discharge, derived from the literature. A better understanding of the phenomenon will assist healthcare professionals to recognize, measure and implement interventions where necessary, to ensure patients are ready for hospital discharge and assist in the advancement of knowledge for all professionals involved in patient discharge from hospital. © 2017 John Wiley & Sons Ltd.

Quantifying alteration of river flow regime by large reservoirs in France

NASA Astrophysics Data System (ADS)

Cipriani, Thomas; Sauquet, Eric

2017-04-01

Reservoirs may highly modify river flow regime. Knowing the alterations is of importance to better understand the biological and physical patterns along the river network. However data are not necessary available to carry out an analysis of modifications at a national scale, e.g. due to industrial interests or to lack of measurements. The objective of this study is to quantify the changes in a set of hydrological indices due to large reservoirs in France combining different data sources. The analysis is based on a comparison between influenced discharges (observed discharges) and natural discharges available from: (i) gauging stations available upstream the dam, (ii) regionalization procedures (Sauquet et al., 2008; Sauquet et Catalogne, 2011; Cipriani et al., 2012), or (iii) historical data free from human influence close to the dam location. The impact of large reservoirs is assessed considering different facets of the river flow regime, including flood quantiles, low flow characteristics, quantiles from the flow duration curve and the twelve mean monthly discharges. The departures from the indice representative of natural conditions quantify the effect of the reservoir management on the river flow regime. The analysis is based on 62 study cases. Results show large spread in terms of impact depending on the purposes of the reservoirs and the season of interest. Results also point out inconsistencies in data (water balance between outflow and inflow, downstream of the dam is not warranted) due to uncertainties in mean monthly discharges and to the imperfect knowledge of inflows and outflows. Lastly, we suggest a typology of hydrological alterations based on the purposes of the reservoirs. Cipriani T., Toilliez T., Sauquet E. (2012). Estimating 10 year return period peak flows and flood durations at ungauged locations in France. La Houille Blanche, 4-5: 5-13, doi : 10.1051/lhb/2012024. Sauquet E., Catalogne C. (2011). Comparison of catchment grouping methods for

Culvert analysis program for indirect measurement of discharge

USGS Publications Warehouse

Fulford, Janice M.; ,

1993-01-01

A program based on the U.S. Geological Survey (USGS) methods for indirectly computing peak discharges through culverts allows users to employ input data formats used by the water surface profile program (WSPRO). The program can be used to compute discharge rating surfaces or curves that describe the behavior of flow through a particular culvert or to compute discharges from measurements of upstream of the gradually varied flow equations and has been adapted slightly to provide solutions that minimize the need for the user to determine between different flow regimes. The program source is written in Fortran 77 and has been run on mini-computers and personal computers. The program does not use or require graphics capability, a color monitor, or a mouse.

Progress toward steady-state tokamak operation exploiting the high bootstrap current fraction regime

DOE PAGES

Ren, Q. L.; Garofalo, A. M.; Gong, X. Z.; ...

2016-06-20

Recent DIII-D experiments have increased the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Improved understanding of scenario stability has led to the achievement of very high values of β p and β N despite strong ITBs. Good confinement has been achieved with reduced toroidal rotation. These high β p plasmas challenge the energy transport understanding, especiallymore » in the electron energy channel. A new turbulent transport model, named 2 TGLF-SAT1, has been developed which improves the transport prediction. Experiments extending results to long pulse on EAST, based on the physics basis developed at DIII-D, have been conducted. Finally, more investigations will be carried out on EAST with more additional auxiliary power to come online in the near term.« less

Development of Partial Discharging Simulation Test Equipment

NASA Astrophysics Data System (ADS)

Kai, Xue; Genghua, Liu; Yan, Jia; Ziqi, Chai; Jian, Lu

2017-12-01

In the case of partial discharge training for recruits who lack of on-site work experience, the risk of physical shock and damage of the test equipment may be due to the limited skill level and improper operation by new recruits. Partial discharge simulation tester is the use of simulation technology to achieve partial discharge test process simulation, relatively true reproduction of the local discharge process and results, so that the operator in the classroom will be able to get familiar with and understand the use of the test process and equipment.The teacher sets up the instrument to display different partial discharge waveforms so that the trainees can analyze the test results of different partial discharge types.

A New Tool for Environmental and Economic Optimization of Hydropower Operations

NASA Astrophysics Data System (ADS)

Saha, S.; Hayse, J. W.

2012-12-01

As part of a project funded by the U.S. Department of Energy, researchers from Argonne, Oak Ridge, Pacific Northwest, and Sandia National Laboratories collaborated on the development of an integrated toolset to enhance hydropower operational decisions related to economic value and environmental performance. As part of this effort, we developed an analytical approach (Index of River Functionality, IRF) and an associated software tool to evaluate how well discharge regimes achieve ecosystem management goals for hydropower facilities. This approach defines site-specific environmental objectives using relationships between environmental metrics and hydropower-influenced flow characteristics (e.g., discharge or temperature), with consideration given to seasonal timing, duration, and return frequency requirements for the environmental objectives. The IRF approach evaluates the degree to which an operational regime meets each objective and produces a score representing how well that regime meets the overall set of defined objectives. When integrated with other components in the toolset that are used to plan hydropower operations based upon hydrologic forecasts and various constraints on operations, the IRF approach allows an optimal release pattern to be developed based upon tradeoffs between environmental performance and economic value. We tested the toolset prototype to generate a virtual planning operation for a hydropower facility located in the Upper Colorado River basin as a demonstration exercise. We conducted planning as if looking five months into the future using data for the recently concluded 2012 water year. The environmental objectives for this demonstration were related to spawning and nursery habitat for endangered fishes using metrics associated with maintenance of instream habitat and reconnection of the main channel with floodplain wetlands in a representative reach of the river. We also applied existing mandatory operational constraints for the

Numerical investigation on the dynamics and evolution mechanisms of multiple-current-pulse behavior in homogeneous helium dielectric-barrier discharges at atmospheric pressure

NASA Astrophysics Data System (ADS)

Zhang, Yuhui; Ning, Wenjun; Dai, Dong

2018-03-01

A systematic investigation on the dynamics and evolution mechanisms of multiple-current-pulse (MCP) behavior in homogeneous dielectric barrier discharge (HDBD) is carried out via fluid modelling. Inspecting the simulation results, two typical discharge regimes, namely the MCP-Townsend regime and MCP-glow regime, are found prevailing in MCP discharges, each with distinctive electrical and dynamic properties. Moreover, the evolution of MCP behavior with external parameters altering are illustrated and explicitly discussed. It is revealed that the discharge undergoes some different stages as external parameters vary, and the discharge in each stage follows a series of distinctive pattern in morphological characteristics and evolution trends. Among those stages, the pulse number per half cycle is perceived to observe non-monotonic variations with applied voltage amplitude (Vam) and gap width (dg) increasing, and a merging effect among pulses, mainly induced by the enhanced contribution of sinusoidal component to the total current, is considered responsible for such phenomenon. The variation of incipient discharge peak phase (Φpm) is dominated by the value of Vam as well as the proportion of total applied voltage that drops across the gas gap. Moreover, an abnormal, dramatic elevation in Jpm with dg increasing is observed, which could be evinced by the strengthened glow discharge structure and therefore enhanced space charge effect.

The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen

2013-06-15

Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of themore » frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage.« less

MHD modeling of DIII-D QH-mode discharges and comparison to observations

NASA Astrophysics Data System (ADS)

King, Jacob

2016-10-01

MHD modeling of DIII-D QH-mode discharges and comparison to observations Nonlinear NIMROD simulations, initialized from a reconstruction of a DIII-D QH-mode discharge with broadband MHD, saturate into a turbulent state, but do not saturate when flow is not included. This is consistent with the experimental results of the quiescent regime observed on DIII-D with broadband MHD activity [Garofalo et al., PoP (2015) and refs. within]. These ELM-free discharges have the normalized pedestal-plasma confinement necessary for burning-plasma operation on ITER. Relative to QH-mode operation with more coherent MHD activity, operation with broadband MHD tends to occur at higher densities and lower rotation and thus may be more relevant to ITER. The nonlinear NIMROD simulations require highly accurate equilibrium reconstructions. Our equilibrium reconstructions include the scrape-off-layer profiles and the measured toroidal and poloidal rotation profiles. The simulation develops into a saturated turbulent state and the n=1 and 2 modes become dominant through an inverse cascade. Each toroidal mode in the range of n=1-5 is dominant at a different time. The perturbations are advected and sheared apart in the counter-clockwise direction consistent with the direction of the poloidal flow inside the LCFS. Work towards validation through comparison to magnetic coil and Doppler reflectometry measurements is presented. Consistent with experimental observations during QH-mode, the simulated state leads to large particle transport relative to the thermal transport. Analysis shows that the phase of the density and temperature perturbations differ resulting in greater convective particle transport relative to the convective thermal transport. This work supported by the U.S. Department of Energy Office of Science and the SciDAC Center for Extended MHD Modeling under Contract Numbers DE-FC02-06ER54875, DE-FC02-08ER54972 and DE-FC02-04ER54698.

High performance advanced tokamak regimes in DIII-D for next-step experiments

NASA Astrophysics Data System (ADS)

Greenfield, C. M.; Murakami, M.; Ferron, J. R.; Wade, M. R.; Luce, T. C.; Petty, C. C.; Menard, J. E.; Petrie, T. W.; Allen, S. L.; Burrell, K. H.; Casper, T. A.; DeBoo, J. C.; Doyle, E. J.; Garofalo, A. M.; Gorelov, I. A.; Groebner, R. J.; Hobirk, J.; Hyatt, A. W.; Jayakumar, R. J.; Kessel, C. E.; La Haye, R. J.; Jackson, G. L.; Lohr, J.; Makowski, M. A.; Pinsker, R. I.; Politzer, P. A.; Prater, R.; Strait, E. J.; Taylor, T. S.; West, W. P.; DIII-D Team

2004-05-01

Advanced Tokamak (AT) research in DIII-D [K. H. Burrell for the DIII-D Team, in Proceedings of the 19th Fusion Energy Conference, Lyon, France, 2002 (International Atomic Energy Agency, Vienna, 2002) published on CD-ROM] seeks to provide a scientific basis for steady-state high performance operation in future devices. These regimes require high toroidal beta to maximize fusion output and poloidal beta to maximize the self-driven bootstrap current. Achieving these conditions requires integrated, simultaneous control of the current and pressure profiles, and active magnetohydrodynamic stability control. The building blocks for AT operation are in hand. Resistive wall mode stabilization via plasma rotation and active feedback with nonaxisymmetric coils allows routine operation above the no-wall beta limit. Neoclassical tearing modes are stabilized by active feedback control of localized electron cyclotron current drive (ECCD). Plasma shaping and profile control provide further improvements. Under these conditions, bootstrap supplies most of the current. Steady-state operation requires replacing the remaining Ohmic current, mostly located near the half radius, with noninductive external sources. In DIII-D this current is provided by ECCD, and nearly stationary AT discharges have been sustained with little remaining Ohmic current. Fast wave current drive is being developed to control the central magnetic shear. Density control, with divertor cryopumps, of AT discharges with edge localized moding H-mode edges facilitates high current drive efficiency at reactor relevant collisionalities. A sophisticated plasma control system allows integrated control of these elements. Close coupling between modeling and experiment is key to understanding the separate elements, their complex nonlinear interactions, and their integration into self-consistent high performance scenarios. Progress on this development, and its implications for next-step devices, will be illustrated by results

Investigation of the Discharge Characteristics of the T6 Hollow Cathode Operating on Several Inert Gases and a Kr/Xe Mixture

NASA Astrophysics Data System (ADS)

Ahmed Rudwan, M.; Gabriel, S. B.

2002-01-01

Investigation of the discharge characteristics of the T6 hollow cathode operating on several inert Xenon is currently the propellant of choice for gridded ion thrusters. But in order to make deep space missions feasible, an increase in the Specific Impulse (SI) that these thrusters can achieve is necessary. One method of achieving this is to use a propellant with a lower atomic mass (e.g. argon), as the propellant exhaust velocity is inversely proportional to the square root of the propellant mass. However, the feasibility of operating the hollow cathode using these alternative propellants has to be demonstrated. Moreover, interest in decreasing the propellant cost in missions and ground testing (especially life tests) have led to the comprehensive discharge characterisation of several gases that will be presented in this paper. A Kr/Xe mixture in the naturally occurring ratio, for example, could offer a 15 times cost saving when compared to pure xenon and 2-3 times cost saving when compared to pure krypton. The T6 hollow cathode discharge behaviour as well as its initiation characteristics have been studied. The tests were carried out in diode configuration using a T6 hollow cathode with an enclosed keeper design employing xenon, krypton, argon and a Kr/Xe mix. The discharge initiation tests were undertaken with a view to investigate some of the factors thought to influence the starting potential such as mass flow rate and tip temperature. It was found that, for mass flow rates ranging from 0.2-1.1 mg/s and cathode tip temperatures ranging from 900-1300oC, the breakdown potential was less than 50V for argon, less than 25V for krypton, less than 21V for xenon and less than 35V for the Kr/Xe mix. The discharge initiation results were then compared to those obtained by Fearn et al. with a T5 cathode operating on mercury and with a T6 cathode utilising an open keeper design using xenon propellant. The xenon breakdown potentials were found to be lower than those

Stability of DIII-D high-performance, negative central shear discharges

NASA Astrophysics Data System (ADS)

Hanson, J. M.; Berkery, J. W.; Bialek, J.; Clement, M.; Ferron, J. R.; Garofalo, A. M.; Holcomb, C. T.; La Haye, R. J.; Lanctot, M. J.; Luce, T. C.; Navratil, G. A.; Olofsson, K. E. J.; Strait, E. J.; Turco, F.; Turnbull, A. D.

2017-05-01

Tokamak plasma experiments on the DIII-D device (Luxon et al 2005 Fusion Sci. Tech. 48 807) demonstrate high-performance, negative central shear (NCS) equilibria with enhanced stability when the minimum safety factor {{q}\\text{min}} exceeds 2, qualitatively confirming theoretical predictions of favorable stability in the NCS regime. The discharges exhibit good confinement with an L-mode enhancement factor H 89  =  2.5, and are ultimately limited by the ideal-wall external kink stability boundary as predicted by ideal MHD theory, as long as tearing mode (TM) locking events, resistive wall modes (RWMs), and internal kink modes are properly avoided or controlled. Although the discharges exhibit rotating TMs, locking events are avoided as long as a threshold minimum safety factor value {{q}\\text{min}}>2 is maintained. Fast timescale magnetic feedback control ameliorates RWM activity, expanding the stable operating space and allowing access to {β\\text{N}} values approaching the ideal-wall limit. Quickly growing and rotating instabilities consistent with internal kink mode dynamics are encountered when the ideal-wall limit is reached. The RWM events largely occur between the no- and ideal-wall pressure limits predicted by ideal MHD. However, evaluating kinetic contributions to the RWM dispersion relation results in a prediction of passive stability in this regime due to high plasma rotation. In addition, the ideal MHD stability analysis predicts that the ideal-wall limit can be further increased to {β\\text{N}}>4 by broadening the current profile. This path toward improved stability has the potential advantage of being compatible with the bootstrap-dominated equilibria envisioned for advanced tokamak (AT) fusion reactors.

On transition from diffuse mode to the constricted one with high-current cathode spot in overvoltage open discharge in D2

NASA Astrophysics Data System (ADS)

Akishev, Yu S.; Karalnik, V. B.; Medvedev, M. A.; Petryakov, A. V.; Trushkin, N. I.; Shafikov, A. G.

2017-11-01

So called “open discharges” in a narrow gap between the solid cathode and grid anode are widely used for generation of the pulsed high-current electron beams with energy up to 100 keV. The need to get high-energy e-beams leads to the necessity in using of strong overvoltage of the short gas gap with the reduced electric field of the order of 105 Td or higher. The discharge under strong overvoltage is unstable and tends to transit into high-current regime with low voltage. In the case of the open discharge in D2 at low pressure (about 0.5-2 Torr) and powered by stepwise voltage with amplitude up to 25 kV we revealed that this discharge exhibits two diffuse regimes which follow one by one and finally transits into the constricted mode with formation of high-current spots on the cathode. The physical properties of these gas discharge regimes have been explored in detail with the usage of the fast multi-frame camera synchronized with the current and voltage of discharge. Our findings promote more insight into physics of the overvoltage open discharge generating the e-beams with energy up to 25 keV.

Compatibility of internal transport barrier with steady-state operation in the high bootstrap fraction regime on DIII-D

DOE PAGES

Garofalo, Andrea M.; Gong, Xianzu; Grierson, Brian A.; ...

2015-11-16

Recent EAST/DIII-D joint experiments on the high poloidal beta tokamak regime in DIII-D have demonstrated fully noninductive operation with an internal transport barrier (ITB) at large minor radius, at normalized fusion performance increased by ≥30% relative to earlier work. The advancement was enabled by improved understanding of the “relaxation oscillations”, previously attributed to repetitive ITB collapses, and of the fast ion behavior in this regime. It was found that the “relaxation oscillations” are coupled core-edge modes 2 amenable to wall-stabilization, and that fast ion losses which previously dictated a large plasma-wall separation to avoid wall over-heating, can be reduced tomore » classical levels with sufficient plasma density. By using optimized waveforms of the plasma-wall separation and plasma density, fully noninductive plasmas have been sustained for long durations with excellent energy confinement quality, bootstrap fraction ≥ 80%, β N ≤ 4 , β P ≥ 3 , and β T ≥ 2%. Finally, these results bolster the applicability of the high poloidal beta tokamak regime toward the realization of a steady-state fusion reactor.« less

Impact of Te and ne on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Dunne, M. G.; Rathgeber, S.; Burckhart, A.; Fischer, R.; Giannone, L.; McCarthy, P. J.; Schneider, P. A.; Wolfrum, E.; the ASDEX Upgrade Team

2015-01-01

ELM resolved edge current density profiles are reconstructed using the CLISTE equilibrium code. As input, highly spatially and temporally resolved edge electron temperature and density profiles are used in addition to data from the extensive set of external poloidal field measurements available at ASDEX Upgrade, flux loop difference measurements, and current measurements in the scrape-off layer. Both the local and flux surface averaged current density profiles are analysed for several ELM mitigation regimes. The focus throughout is on the impact of altered temperature and density profiles on the current density. In particular, many ELM mitigation regimes rely on operation at high density. Two reference plasmas with type-I ELMs are analysed, one with a deuterium gas puff and one without, in order to provide a reference for the behaviour in type-II ELMy regimes and high density ELM mitigation with external magnetic perturbations at ASDEX Upgrade. For type-II ELMs it is found that while a similar pedestal top pressure is sustained at the higher density, the temperature gradient decreases in the pedestal. This results in lower local and flux surface averaged current densities in these phases, which reduces the drive for the peeling mode. No significant differences between the current density measured in the type-I phase and ELM mitigated phase is seen when external perturbations are applied, though the pedestal top density was increased. Finally, ELMs during the nitrogen seeded phase of a high performance discharge are analysed and compared to ELMs in the reference phase. An increased pedestal pressure gradient, which is the source of confinement improvement in impurity seeded discharges, causes a local current density increase. However, the increased Zeff in the pedestal acts to reduce the flux surface averaged current density. This dichotomy, which is not observed in other mitigation regimes, could act to stabilize both the ballooning mode and the peeling mode at the

Achievement of radiative feedback control for long-pulse operation on EAST

NASA Astrophysics Data System (ADS)

Wu, K.; Yuan, Q. P.; Xiao, B. J.; Wang, L.; Duan, Y. M.; Chen, J. B.; Zheng, X. W.; Liu, X. J.; Zhang, B.; Xu, J. C.; Luo, Z. P.; Zang, Q.; Li, Y. Y.; Feng, W.; Wu, J. H.; Yang, Z. S.; Zhang, L.; Luo, G.-N.; Gong, X. Z.; Hu, L. Q.; Hu, J. S.; Li, J.

2018-05-01

The active feedback control of radiated power to prevent divertor target plates overheating during long-pulse operation has been developed and implemented on EAST. The radiation control algorithm, with impurity seeding via a supersonic molecular beam injection (SMBI) system, has shown great success in both reliability and stability. By seeding a sequence of short neon (Ne) impurity pulses with the SMBI from the outer mid-plane, the radiated power of the bulk plasma can be well controlled, and the duration of radiative control (feedforward and feedback) is 4.5 s during a discharge of 10 s. Reliable control of the total radiated power of bulk plasma has been successfully achieved in long-pulse upper single null (USN) discharges with a tungsten divertor. The achieved control range of {{f}rad} is 20%–30% in L-mode regimes and 18%–36% in H-mode regimes. The temperature of the divertor target plates was maintained at a low level during the radiative control phase. The peak particle flux on the divertor target was decreased by feedforward Ne injection in the L-mode discharges, while the Ne pulses from the SMBI had no influence on the peak particle flux because of the very small injecting volume. It is shown that although the radiated power increased, no serious reduction of plasma-stored energy or confinement was observed during the control phase. The success of the radiation control algorithm and current experiments in radiated power control represents a significant advance for steady-state divertor radiation and heat flux control on EAST for near-future long-pulse operation.

Operating Spin Echo in the Quantum Regime for an Atomic-Ensemble Quantum Memory

NASA Astrophysics Data System (ADS)

Rui, Jun; Jiang, Yan; Yang, Sheng-Jun; Zhao, Bo; Bao, Xiao-Hui; Pan, Jian-Wei

2015-09-01

Spin echo is a powerful technique to extend atomic or nuclear coherence times by overcoming the dephasing due to inhomogeneous broadenings. However, there are disputes about the feasibility of applying this technique to an ensemble-based quantum memory at the single-quanta level. In this experimental study, we find that noise due to imperfections of the rephasing pulses has both intense superradiant and weak isotropic parts. By properly arranging the beam directions and optimizing the pulse fidelities, we successfully manage to operate the spin echo technique in the quantum regime by observing nonclassical photon-photon correlations as well as the quantum behavior of retrieved photons. Our work for the first time demonstrates the feasibility of harnessing the spin echo method to extend the lifetime of ensemble-based quantum memories at the single-quanta level.

Prospects for Alpha Particle Heating in JET in the Hot Ion Regime

NASA Astrophysics Data System (ADS)

Cordey, J. G.; Keilhacker, M.; Watkins, M. L.

1987-01-01

The prospects for alpha particle heating in JET are discussed. A computational model is developed to represent adequately the neutron yield from JET plasmas heated by neutral beam injection. This neutral beam model, augmented by a simple plasma model, is then used to determine the neutron yields and fusion Q-values anticipated for different heating schemes in future operation of JET with tritium. The relative importance of beam-thermal and thermal-thermal reactions is pointed out and the dependence of the results on, for example, plasma density, temperature, energy confinement and purity is shown. Full 1½-D transport code calculations, based on models developed for ohmic, ICRF and NBI heated JET discharges, are used also to provide a power scan for JET operation in tritium in the low density, high ion temperature regime. The results are shown to be in good agreement with the estimates made using the simple plasma model and indicate that, based on present knowledge, a fusion Q-value in the plasma centre above unity should be achieved in JET.

The potential for facilitating spring discharge from continental climate waste stabilisation ponds by carry-over of treated wastewater: concepts and experimental findings.

PubMed

Whalley, C; Pak, L N; Heaven, S

2007-01-01

The research investigated some factors influencing the rate of stabilisation of wastewater in the spring period in continental climate waste stabilisation ponds, and in particular the potential for bringing forward the discharge date by optimising storage capacity and dilution. Experiments using pilot and modelscale ponds were set up in Almaty, Kazakhstan. These simulated operating regimes for a facultative and storage/maturation pond system subject to ice cover from late November until late March. Two pilot-scale facultative ponds were operated at hydraulic retention times (HRT) of 20 and 30 days, with surface loading rates of 100 and 67 kg BOD ha(-1) day(-1). Effluent from the 20-day HRT facultative pond was then fed to two pilot-scale storage/maturation ponds which had been partially emptied and allowed to refill over the winter period with no removal of effluent. The paper discusses the results of the experiments with respect to selection of an operating regime to make treated wastewater available early in the spring. Preliminary results indicate that there may be potential for alternative operating protocols designed to maximise their performance and economic potential.

Cold starting of fluorescent lamps - part I: a description of the transient regime

NASA Astrophysics Data System (ADS)

Langer, Reinhard; Garner, Richard; Paul, Irina; Horn, Siegfried; Tidecks, Reinhard

2016-10-01

In this paper we give a proposal for the transient behaviour of a cold-started fluorescent lamp, from the generation of the first conductive channel over the normal and abnormal glow discharge and the glow-to-arc (GTA) transition to the arc discharge in the steady state. Starting from the equilibrium voltage-current characteristics of the lamp and considering recent experimental results a qualitative description of the transient regime is developed, which was so far not available in the literature.

Can global hydrological models reproduce large scale river flood regimes?

NASA Astrophysics Data System (ADS)

Eisner, Stephanie; Flörke, Martina

2013-04-01

River flooding remains one of the most severe natural hazards. On the one hand, major flood events pose a serious threat to human well-being, causing deaths and considerable economic damage. On the other hand, the periodic occurrence of flood pulses is crucial to maintain the functioning of riverine floodplains and wetlands, and to preserve the ecosystem services the latter provide. In many regions, river floods reveal a distinct seasonality, i.e. they occur at a particular time during the year. This seasonality is related to regionally dominant flood generating processes which can be expressed in river flood types. While in data-rich regions (esp. Europe and North America) the analysis of flood regimes can be based on observed river discharge time series, this data is sparse or lacking in many other regions of the world. This gap of knowledge can be filled by global modeling approaches. However, to date most global modeling studies have focused on mean annual or monthly water availability and their change over time while simulating discharge extremes, both floods and droughts, still remains a challenge for large scale hydrological models. This study will explore the ability of the global hydrological model WaterGAP3 to simulate the large scale patterns of river flood regimes, represented by seasonal pattern and the dominant flood type. WaterGAP3 simulates the global terrestrial water balance on a 5 arc minute spatial grid (excluding Greenland and Antarctica) at a daily time step. The model accounts for human interference on river flow, i.e. water abstraction for various purposes, e.g. irrigation, and flow regulation by large dams and reservoirs. Our analysis will provide insight in the general ability of global hydrological models to reproduce river flood regimes and thus will promote the creation of a global map of river flood regimes to provide a spatially inclusive and comprehensive picture. Understanding present-day flood regimes can support both flood risk

Plasma treatment of polyethylene tubes in continuous regime using surface dielectric barrier discharge with water electrodes

NASA Astrophysics Data System (ADS)

Galmiz, Oleksandr; Zemánek, Miroslav; Pavliňák, David; Černák, Mirko

2018-05-01

Combining the surface dielectric barrier discharges generated in contact with water based electrolytes, as the discharge electrodes, we have designed a new type of surface electric discharge, generating thin layers of plasma which propagate along the treated polymer surfaces. The technique was aimed to achieve uniform atmospheric pressure plasma treatment of polymeric tubes and other hollow bodies. The results presented in this work show the possibility of such system to treat outer surface of polymer materials in a continuous mode. The technical details of experimental setup are discussed as well as results of treatment of polyethylene tubes are shown.

Optimizing Wellfield Operation in a Variable Power Price Regime.

PubMed

Bauer-Gottwein, Peter; Schneider, Raphael; Davidsen, Claus

2016-01-01

Wellfield management is a multiobjective optimization problem. One important objective has been energy efficiency in terms of minimizing the energy footprint (EFP) of delivered water (MWh/m(3) ). However, power systems in most countries are moving in the direction of deregulated markets and price variability is increasing in many markets because of increased penetration of intermittent renewable power sources. In this context the relevant management objective becomes minimizing the cost of electric energy used for pumping and distribution of groundwater from wells rather than minimizing energy use itself. We estimated EFP of pumped water as a function of wellfield pumping rate (EFP-Q relationship) for a wellfield in Denmark using a coupled well and pipe network model. This EFP-Q relationship was subsequently used in a Stochastic Dynamic Programming (SDP) framework to minimize total cost of operating the combined wellfield-storage-demand system over the course of a 2-year planning period based on a time series of observed price on the Danish power market and a deterministic, time-varying hourly water demand. In the SDP setup, hourly pumping rates are the decision variables. Constraints include storage capacity and hourly water demand fulfilment. The SDP was solved for a baseline situation and for five scenario runs representing different EFP-Q relationships and different maximum wellfield pumping rates. Savings were quantified as differences in total cost between the scenario and a constant-rate pumping benchmark. Minor savings up to 10% were found in the baseline scenario, while the scenario with constant EFP and unlimited pumping rate resulted in savings up to 40%. Key factors determining potential cost savings obtained by flexible wellfield operation under a variable power price regime are the shape of the EFP-Q relationship, the maximum feasible pumping rate and the capacity of available storage facilities. © 2015 The Authors. Groundwater published by Wiley

Electronic perturbation investigations into excitation and ionization in the millisecond pulsed glow discharge plasma

NASA Astrophysics Data System (ADS)

Li, Lei; Robertson-Honecker, Jennifer; Vaghela, Vishal; King, Fred L.

2006-06-01

This study employed a power perturbation method to examine the energy transfer processes at different locations within the afterpeak regime of a millisecond pulsed glow discharge plasma. Brief power perturbation pulses were applied during the afterpeak regime altering the environment of the collapsing plasma. Responses of several transitions to the power perturbations were measured via atomic emission and absorption spectroscopic methods at various distances from the surface of the cathode. The experimental data provide further insight into the energy transfer processes that occur at different spatial locations and in different temporal regimes of these pulsed glow discharge plasmas. Although the enhancement of the large population of metastable argon atoms is again confirmed, the mechanism responsible for this enhancement remains unclear. The most likely possibility involves some form of ion-electron recombination followed by radiative relaxation of the resulting species. The metastable argon atoms subsequently Penning ionize sputtered copper atoms which then appear to undergo a similar ion-electron recombination process yielding variable degrees of observable afterpeak emission for copper atom transitions. The kinetic information of these processes was approximated from the corresponding relaxation time. The electron thermalization time allowing for recombination with ions was found to be ˜25 μs after the discharge power termination.

Influence of ion source configuration and its operation parameters on the target sputtering and implantation process.

PubMed

Shalnov, K V; Kukhta, V R; Uemura, K; Ito, Y

2012-06-01

In the work, investigation of the features and operation regimes of sputter enhanced ion-plasma source are presented. The source is based on the target sputtering with the dense plasma formed in the crossed electric and magnetic fields. It allows operation with noble or reactive gases at low pressure discharge regimes, and, the resulting ion beam is the mixture of ions from the working gas and sputtering target. Any conductive material, such as metals, alloys, or compounds, can be used as the sputtering target. Effectiveness of target sputtering process with the plasma was investigated dependently on the gun geometry, plasma parameters, and the target bias voltage. With the applied accelerating voltage from 0 to 20 kV, the source can be operated in regimes of thin film deposition, ion-beam mixing, and ion implantation. Multi-component ion beam implantation was applied to α-Fe, which leads to the surface hardness increasing from 2 GPa in the initial condition up to 3.5 GPa in case of combined N(2)-C implantation. Projected range of the implanted elements is up to 20 nm with the implantation energy 20 keV that was obtained with XPS depth profiling.

Investigation of complexity dynamics in a DC glow discharge magnetized plasma using recurrence quantification analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitra, Vramori; Sarma, Bornali; Sarma, Arun

Recurrence is an ubiquitous feature which provides deep insights into the dynamics of real dynamical systems. A suitable tool for investigating recurrences is recurrence quantification analysis (RQA). It allows, e.g., the detection of regime transitions with respect to varying control parameters. We investigate the complexity of different coexisting nonlinear dynamical regimes of the plasma floating potential fluctuations at different magnetic fields and discharge voltages by using recurrence quantification variables, in particular, DET, L{sub max}, and Entropy. The recurrence analysis reveals that the predictability of the system strongly depends on discharge voltage. Furthermore, the persistent behaviour of the plasma time seriesmore » is characterized by the Detrended fluctuation analysis technique to explore the complexity in terms of long range correlation. The enhancement of the discharge voltage at constant magnetic field increases the nonlinear correlations; hence, the complexity of the system decreases, which corroborates the RQA analysis.« less

Catchment heterogeneity controls emergent archetype concentration-discharge relationships

NASA Astrophysics Data System (ADS)

Musolff, A.; Fleckenstein, J. H.; Rao, P. S.; Jawitz, J. W.

2017-12-01

Relationships between in-stream dissolved solute concentrations (C) and discharge (Q) are often-used indicators of catchment-scale processes and their interference with human activities. Here we analyze observational C-Q relationships from 61 catchments and 8 different solutes across a wide range of land-uses and discharge regimes. This analysis is combined with a parsimonious stochastic modeling approach to test how C-Q relationships arise from spatial heterogeneity in catchment solute sources coupled with different timescales of biogeochemical reactions. The observational data exhibit archetypical dilution, enrichment, and constant C-Q patterns. Moreover, with land-use intensification we find decreasing C variability relative to Q variability (chemostatic export regime). Our model indicates that the dominant driver of emergent C-Q patterns was structured heterogeneity of solute sources implemented as correlation of source concentration to travel time. Regardless of the C-Q pattern, with decreasing source heterogeneity we consistently find lower variability in C than in Q and a dominance of chemostatic export regimes. Here, the variance in exported loads is determined primarily by variance of Q. We conclude that efforts to improve stream water quality and ecological integrity in intensely managed catchments should lead away from landscape homogenization by introducing structured source heterogeneity. References: Musolff, A., J. H. Fleckenstein, P. S. C. Rao, and J. W. Jawitz (2017), Emergent archetype patterns of coupled hydrologic and biogeochemical responses in catchments, Geophys. Res. Lett., 44(9), 4143-4151, doi: 10.1002/2017GL072630.

Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

PubMed

Anpilov, A M; Barkhudarov, E M; Christofi, N; Kop'ev, V A; Kossyi, I A; Taktakishvili, M I; Zadiraka, Y

2002-01-01

To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

Integrated scheduling of a container handling system with simultaneous loading and discharging operations

NASA Astrophysics Data System (ADS)

Li, Chen; Lu, Zhiqiang; Han, Xiaole; Zhang, Yuejun; Wang, Li

2016-03-01

The integrated scheduling of container handling systems aims to optimize the coordination and overall utilization of all handling equipment, so as to minimize the makespan of a given set of container tasks. A modified disjunctive graph is proposed and a mixed 0-1 programming model is formulated. A heuristic algorithm is presented, in which the original problem is divided into two subproblems. In the first subproblem, contiguous bay crane operations are applied to obtain a good quay crane schedule. In the second subproblem, proper internal truck and yard crane schedules are generated to match the given quay crane schedule. Furthermore, a genetic algorithm based on the heuristic algorithm is developed to search for better solutions. The computational results show that the proposed algorithm can efficiently find high-quality solutions. They also indicate the effectiveness of simultaneous loading and discharging operations compared with separate ones.

Analysis of Alfven eigenmode destabilization in DIII-D high poloidal β discharges using a Landau closure model

NASA Astrophysics Data System (ADS)

Varela, J.; Spong, D. A.; Garcia, L.; Huang, J.; Murakami, M.; Garofalo, A. M.; Qian, J. P.; Holcomb, C. T.; Hyatt, A. W.; Ferron, J. R.; Collins, C. S.; Ren, Q. L.; McClenaghan, J.; Guo, W.

2018-07-01

Alfvén eigenmodes are destabilized at the DIII-D pedestal during transient beta drops in high poloidal β discharges with internal transport barriers (ITBs), driven by n  =  1 external kink modes, leading to energetic particle losses. There are two different scenarios in the thermal β recovery phase: with bifurcation (two instability branches with different frequencies) or without bifurcation (single instability branch). We use the reduced MHD equations in a full 3D system, coupled with equations of density and parallel velocity moments for the energetic particles as well as the geodesic acoustic wave dynamics, to study the properties of the instabilities observed in the DIII-D high poloidal β discharges and identify the conditions to trigger the bifurcation. The simulations suggest that instabilities with lower frequency in the bifurcation case are ballooning modes driven at the plasma pedestal, while the instability branch with higher frequencies are low n (n  <  4) toroidal Alfvén eigenmodes nearby the pedestal. The reverse shear region between the middle and plasma periphery in the non-bifurcated case avoids the excitation of ballooning modes at the pedestal, although toroidal Alfvén eigenmodes and reverse shear Alfvén eigenmodes are unstable in the reverse shear region. The n  =  1 and n  =  2 Alfvén eigenmode activity can be suppressed or minimized if the neutral beam injector (NBI) intensity is lower than the experimental value (). In addition, if the beam energy or neutral beam injector voltage is lower than in the experiment (), the resonance between beam and thermal plasma is weaker. The and 6 AE activity can not be fully suppressed, although the growth rate and frequency is smaller for an optimized neutral beam injector operation regime. In conclusion, AE activity in high poloidal β discharges can be minimized for optimized NBI operation regimes.

Atmospheric sampling glow discharge ionization source

DOEpatents

McLuckey, Scott A.; Glish, Gary L.

1989-01-01

An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above.

Atmospheric sampling glow discharge ionization source

DOEpatents

McLuckey, S.A.; Glish, G.L.

1989-07-18

An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

Predictive Models of the Hydrological Regime of Unregulated Streams in Arizona

USGS Publications Warehouse

Anning, David W.; Parker, John T.C.

2009-01-01

Three statistical models were developed by the U.S. Geological Survey in cooperation with the Arizona Department of Environmental Quality to improve the predictability of flow occurrence in unregulated streams throughout Arizona. The models can be used to predict the probabilities of the hydrological regime being one of four categories developed by this investigation: perennial, which has streamflow year-round; nearly perennial, which has streamflow 90 to 99.9 percent of the year; weakly perennial, which has streamflow 80 to 90 percent of the year; or nonperennial, which has streamflow less than 80 percent of the year. The models were developed to assist the Arizona Department of Environmental Quality in selecting sites for participation in the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program. One model was developed for each of the three hydrologic provinces in Arizona - the Plateau Uplands, the Central Highlands, and the Basin and Range Lowlands. The models for predicting the hydrological regime were calibrated using statistical methods and explanatory variables of discharge, drainage-area, altitude, and location data for selected U.S. Geological Survey streamflow-gaging stations and a climate index derived from annual precipitation data. Models were calibrated on the basis of streamflow data from 46 stations for the Plateau Uplands province, 82 stations for the Central Highlands province, and 90 stations for the Basin and Range Lowlands province. The models were developed using classification trees that facilitated the analysis of mixed numeric and factor variables. In all three models, a threshold stream discharge was the initial variable to be considered within the classification tree and was the single most important explanatory variable. If a stream discharge value at a station was below the threshold, then the station record was determined as being nonperennial. If, however, the stream discharge was above the threshold

Impurity transport in enhanced confinement regimes in RFX-mod Reversed Field Pinch

NASA Astrophysics Data System (ADS)

Carraro, Lorella; Menmuir, Sheena; Fassina, Alessandro

2010-11-01

The results of impurity transport studies in RFX-mod enhanced confinement quasi-single helicity (QSH) and single helical axis (SHAx) regimes are presented and discussed. The impurity diffusion coefficient and pinch velocity are obtained through comparing experimental emission pattern (line emission and SXR time evolutions, SXR profiles) with the results of a 1-D impurity transport code. Previous analysis [S. Menmuir et al. to be published in Plasma Phys. Contr. Fus.] of impurity transport in RFX-mod standard discharges showed that the impurity pinch velocity, always directed outwards, features a barrier with high values around r/a = 0.8, where the diffusion coefficient decreases by one order of magnitude. In the QSH regime, the transition region in D and v is more internal and the barrier in velocity is wider and stronger. New results have been obtained in experiments with Ni laser blow-off (LBO) injection in high current discharges (Ip>1.5 MA) with long lasting QSH, to better characterize the Ni behavior inside the helical magnetic topology.

Effects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations

USGS Publications Warehouse

Brown, Larry R.; Bauer, Marissa L.

2010-01-01

Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools. In this paper, we evaluate how existing hydrologic infrastructure and management affect streamflow characteristics of rivers in the Central Valley, California and discuss those characteristics in the context of habitat requirements of native and alien fishes. We evaluated the effects of water management by comparing observed discharges with estimated discharges assuming no water management ("full natural runoff"). Rivers in the Sacramento River drainage were characterized by reduced winter–spring discharges and augmented discharges in other months. Rivers in the San Joaquin River drainage were characterized by reduced discharges in all months but particularly in winter and spring. Two largely unaltered streams had hydrographs similar to those based on full natural runoff of the regulated rivers. The reduced discharges in the San Joaquin River drainage streams are favourable for spawning of many alien species, which is consistent with observed patterns of fish distribution and abundance in the Central Valley. However, other factors, such as water temperature, are also important to the relative success of native and alien resident fishes. As water management changes in response to climate change and societal demands, interdisciplinary programs of research and monitoring will be essential for anticipating effects on fishes and to avoid unanticipated ecological outcomes.

HOLLOW CARBON ARC DISCHARGE

DOEpatents

Luce, J.S.

1960-10-11

A device is described for producing an energetic, direct current, hollow, carbon-arc discharge in an evacuated container and within a strong magnetic field. Such discharges are particularly useful not only in dissociation and ionization of high energy molecular ion beams, but also in acting as a shield or barrier against the instreaming of lowenergy neutral particles into a plasma formed within the hollow discharge when it is used as a dissociating mechanism for forming the plasma. There is maintained a predetermined ratio of gas particles to carbon particles released from the arc electrodes during operation of the discharge. The carbon particles absorb some of the gas particles and are pumped along and by the discharge out of the device, with the result that smaller diffusion pumps are required than would otherwise be necessary to dispose of the excess gas.

Deltas, freshwater discharge, and waves along the Young Sound, NE Greenland.

PubMed

Kroon, Aart; Abermann, Jakob; Bendixen, Mette; Lund, Magnus; Sigsgaard, Charlotte; Skov, Kirstine; Hansen, Birger Ulf

2017-02-01

A wide range of delta morphologies occurs along the fringes of the Young Sound in Northeast Greenland due to spatial heterogeneity of delta regimes. In general, the delta regime is related to catchment and basin characteristics (geology, topography, drainage pattern, sediment availability, and bathymetry), fluvial discharges and associated sediment load, and processes by waves and currents. Main factors steering the Arctic fluvial discharges into the Young Sound are the snow and ice melt and precipitation in the catchment, and extreme events like glacier lake outburst floods (GLOFs). Waves are subordinate and only rework fringes of the delta plain forming sandy bars if the exposure and fetch are optimal. Spatial gradients and variability in driving forces (snow and precipitation) and catchment characteristics (amount of glacier coverage, sediment characteristics) as well as the strong and local influence of GLOFs in a specific catchment impede a simple upscaling of sediment fluxes from individual catchments toward a total sediment flux into the Young Sound.

Radiation transport in kinetic simulations and the influence of photoemission on electron current in self-sustaining discharges

DOE PAGES

Fierro, Andrew S.; Moore, Christopher Hudson; Scheiner, Brett; ...

2017-01-12

A kinetic description for electronic excitation of helium for principal quantum number nmore » $$\\leqslant $$ 4 has been included into a particle-in-cell (PIC) simulation utilizing direct simulation Monte Carlo (DSMC) for electron-neutral interactions. The excited electronic levels radiate state-dependent photons with wavelengths from the extreme ultraviolet (EUV) to visible regimes. Photon wavelengths are chosen according to a Voigt distribution accounting for the natural, pressure, and Doppler broadened linewidths. This method allows for reconstruction of the emission spectrum for a non-thermalized electron energy distribution function (EEDF) and investigation of high energy photon effects on surfaces, specifically photoemission. A parallel plate discharge with a fixed field (i.e. space charge neglected) is used to investigate the effects of including photoemission for a Townsend discharge. When operating at a voltage near the self-sustaining discharge threshold, it is observed that the electron current into the anode is higher when including photoemission from the cathode than without even when accounting for self-absorption from ground state atoms. As a result, the photocurrent has been observed to account for as much as 20% of the total current from the cathode under steady-state conditions.« less

Advances in the high bootstrap fraction regime on DIII-D towards the Q = 5 mission of ITER steady state

DOE PAGES

Qian, Jinping P.; Garofalo, Andrea M.; Gong, Xianzu Z.; ...

2017-03-20

Recent EAST/DIII-D joint experiments on the high poloidal betamore » $${{\\beta}_{\\text{P}}}$$ regime in DIII-D have extended operation with internal transport barriers (ITBs) and excellent energy confinement (H 98y2 ~ 1.6) to higher plasma current, for lower q 95 ≤ 7.0, and more balanced neutral beam injection (NBI) (torque injection < 2 Nm), for lower plasma rotation than previous results. Transport analysis and experimental measurements at low toroidal rotation suggest that the E × B shear effect is not key to the ITB formation in these high $${{\\beta}_{\\text{P}}}$$ discharges. Experiments and TGLF modeling show that the Shafranov shift has a key stabilizing effect on turbulence. Extrapolation of the DIII-D results using a 0D model shows that with the improved confinement, the high bootstrap fraction regime could achieve fusion gain Q = 5 in ITER at $${{\\beta}_{\\text{N}}}$$ ~ 2.9 and q 95 ~ 7. With the optimization of q(0), the required improved confinement is achievable when using 1.5D TGLF-SAT1 for transport simulations. Furthermore, results reported in this paper suggest that the DIII-D high $${{\\beta}_{\\text{P}}}$$ scenario could be a candidate for ITER steady state operation.« less

INTENSE ENERGETIC GAS DISCHARGE

DOEpatents

Luce, J.S.

1960-03-01

A method and apparatus for initiating and sustaining an energetic gas arc discharge are described. A hollow cathode and a hollow anode are provided. By regulating the rate of gas flow into the interior of the cathode, the arc discharge is caused to run from the inner surface of the cathode with the result that adequate space-charge neutralization is provided inside the cathode but not in the main arc volume. Thus, the gas fed to the cathode is substantially completely ionized before it leaves the cathode, with the result that an energetic arc discharge can be maintained at lower operating pressures.

Discharge measurements using a broad-band acoustic Doppler current profiler

USGS Publications Warehouse

Simpson, Michael R.

2002-01-01

The measurement of unsteady or tidally affected flow has been a problem faced by hydrologists for many years. Dynamic discharge conditions impose an unreasonably short time constraint on conventional current-meter discharge-measurement methods, which typically last a minimum of 1 hour. Tidally affected discharge can change more than 100 percent during a 10-minute period. Over the years, the U.S. Geological Survey (USGS) has developed moving-boat discharge-measurement techniques that are much faster but less accurate than conventional methods. For a bibliography of conventional moving-boat publications, see Simpson and Oltmann (1993, page 17). The advent of the acoustic Doppler current profiler (ADCP) made possible the development of a discharge-measurement system capable of more accurately measuring unsteady or tidally affected flow. In most cases, an ADCP discharge-measurement system is dramatically faster than conventional discharge-measurement systems, and has comparable or better accuracy. In many cases, an ADCP discharge-measurement system is the only choice for use at a particular measurement site. ADCP systems are not yet ?turnkey;? they are still under development, and for proper operation, require a significant amount of operator training. Not only must the operator have a rudimentary knowledge of acoustic physics, but also a working knowledge of ADCP operation, the manufacturer's discharge-measurement software, and boating techniques and safety.

Discharge transient coupling in large space power systems

NASA Technical Reports Server (NTRS)

Stevens, N. John; Stillwell, R. P.

1990-01-01

Experiments have shown that plasma environments can induce discharges in solar arrays. These plasmas simulate the environments found in low earth orbits where current plans call for operation of very large power systems. The discharges could be large enough to couple into the power system and possibly disrupt operations. Here, the general concepts of the discharge mechanism and the techniques of coupling are discussed. Data from both ground and flight experiments are reviewed to obtain an expected basis for the interactions. These concepts were applied to the Space Station solar array and distribution system as an example of the large space power system. The effect of discharges was found to be a function of the discharge site. For most sites in the array discharges would not seriously impact performance. One location at the negative end of the array was identified as a position where discharges could couple to charge stored in system capacitors. This latter case could impact performance.

Investigation of operating parameters on CO2 splitting by dielectric barrier discharge plasma

NASA Astrophysics Data System (ADS)

Pan, CHEN; Jun, SHEN; Tangchun, RAN; Tao, YANG; Yongxiang, YIN

2017-12-01

Experiments of CO2 splitting by dielectric barrier discharge (DBD) plasma were carried out, and the influence of CO2 flow rate, plasma power, discharge voltage, discharge frequency on CO2 conversion and process energy efficiency were investigated. It was shown that the absolute quantity of CO2 decomposed was only proportional to the amount of conductive electrons across the discharge gap, and the electron amount was proportional to the discharge power; the energy efficiency of CO2 conversion was almost a constant at a lower level, which was limited by CO2 inherent discharge character that determined a constant gap electric field strength. This was the main reason why CO2 conversion rate decreased as the CO2 flow rate increase and process energy efficiency was decreased a little as applied frequency increased. Therefore, one can improve the CO2 conversion by less feed flow rate or larger discharge power in DBD plasma, but the energy efficiency is difficult to improve.

33 CFR 154.1120 - Operating restrictions and interim operating authorization.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Facility Operating in Prince William Sound, Alaska § 154.1120 Operating restrictions and interim operating authorization. (a) The owner or operator of a TAPAA facility may not operate in Prince William Sound, Alaska... practicable, a worst case discharge or a discharge of 200,000 barrels of oil, whichever is grater, in Prince...

AC Glow Discharge Plasma in N2O

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yousif, F. B.; Martinez, H.; Robledo-Martinez, A.

2006-12-04

This paper considers the optical and electrical characterization of AC glow discharge plasma in the abnormal glow mode used for optical emission spectroscopy. The total discharge current and applied voltage are measured using conventional techniques. The electrical characteristics of the planer-cathode glow discharge confirmed that the plasma is operating at abnormal discharge mode characterized by the increases in the operating voltage as the current was raised under given pressure. Optical emission spectroscopy was used to determine the main emission lines of the glow discharge plasma of N2O at pressures between 0.5 and 4.0 Torr. It shows that the discharge emissionmore » range is mainly within 300-400 nm. The emission lines correspond to NO, O2, and O{sub 2}{sup +} are the dominant lines in the glow discharge plasma in the present study. Intensity of the emission lines show linear increase with the discharge current up to 0.4 A followed by saturation at higher currents. No emission lines were observed in this work corresponding to atomic oxygen or nitrogen.« less

Ozone generation in a kHz-pulsed He-O2 capillary dielectric barrier discharge operated in ambient air

NASA Astrophysics Data System (ADS)

Sands, Brian L.; Ganguly, Biswa N.

2013-12-01

The generation of reactive oxygen species using nonequilibrium atmospheric pressure plasma jet devices has been a subject of recent interest due to their ability to generate localized concentrations from a compact source. To date, such studies with plasma jet devices have primarily utilized radio-frequency excitation. In this work, we characterize ozone generation in a kHz-pulsed capillary dielectric barrier discharge configuration comprised of an active discharge plasma jet operating in ambient air that is externally grounded. The plasma jet flow gas was composed of helium with an admixture of up to 5% oxygen. A unipolar voltage pulse train with a 20 ns pulse risetime was used to drive the discharge at repetition rates between 2-25 kHz. Using UVLED absorption spectroscopy centered at 255 nm near the Hartley-band absorption peak, ozone was detected over 1 cm from the capillary axis. We observed roughly linear scaling of ozone production with increasing pulse repetition rate up to a "turnover frequency," beyond which ozone production steadily dropped and discharge current and 777 nm O(5P→5S°) emission sharply increased. The turnover in ozone production occurred at higher pulse frequencies with increasing flow rate and decreasing applied voltage with a common energy density of 55 mJ/cm3 supplied to the discharge. The limiting energy density and peak ozone production both increased with increasing O2 admixture. The power dissipated in the discharge was obtained from circuit current and voltage measurements using a modified parallel plate dielectric barrier discharge circuit model and the volume-averaged ozone concentration was derived from a 2D ozone absorption measurement. From these measurements, the volume-averaged efficiency of ozone production was calculated to be 23 g/kWh at conditions for peak ozone production of 41 mg/h at 11 kV applied voltage, 3% O2, 2 l/min flow rate, and 13 kHz pulse repetition rate, with 1.79 W dissipated in the discharge.

40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

Code of Federal Regulations, 2014 CFR

2014-07-01

... Monitoring for Pre-existing Discharges at Remining Operations B Appendix B to Part 434 Protection of.... B Appendix B to Part 434—Baseline Determination and Compliance Monitoring for Pre-existing... monthly (single-observation) procedure and an annual procedure shall be applied, as described below. b. In...

The simultaneous discharge of liquid and grains from a silo

NASA Astrophysics Data System (ADS)

Cervantes-Álvarez, A. M.; Hidalgo-Caballero, S.; Pacheco-Vázquez, F.

2018-04-01

The flow rate of water through an orifice at the bottom of a container depends on the hydrostatic pressure whereas for a dry granular material it is nearly constant. But what happens during the simultaneous discharge of grains and liquid from a silo? By measuring the flow rate as a function of time, we found that (i) different regimes appear, going from the constant flow rate to a hydrostatic-like discharge depending on the aperture size and grain diameter, (ii) the mixed material is always discharged faster than dry grains but slower than liquid, (iii) for the mixture, the liquid level drops faster than the grain level, but they are always linearly proportional to one another, and (iv) a sudden growth in the flow rate happens during the transition from a biphasic discharge to a single phase discharge. These results are associated to the competition between the decrease in hydrostatic pressure above the granular bed and the hydrodynamic resistance. A model combining Darcy's law with Bernoulli and mass conservation equations is proposed, and the numerical results are in good agreement with experiments.

Glacier retreat and projected river regime changes in the hydrologically highly-coupled Virkisjökull catchment, Iceland

NASA Astrophysics Data System (ADS)

Flett, Verity; Kirkbride, Martin; Black, Andrew; Everest, Jez; MacDonald, Alan

2016-04-01

Virkisjökull, an outlet glacier of the Oræfajökull icecap in SE Iceland, currently has 60% glacier cover, though this is reducing due to glacier retreat. Intensive monitoring over the last 4 years includes measurement of measuring ice ablation, proglacial discharge, dye-tracing of flow pathways, and deployment of three automatic weather stations at altitudes up to 880 m. These data calibrate a distributed hydrological model (WaSIM) to project potential river regime during stages of glacier retreat. Results show: (1) glacier hypsometry sensitises the catchment to a disproportionately rapid increase in runoff as the snowline rises onto a gentle ice cap resulting in in a potential annual increase in river discharge of up to 37% (2) a dominantly channelized glacial drainage system in all seasons with a rapid runoff response to melt: englacial flow of 0.58 m s-1 is comparable to the proglacial river velocity; and (3) longer-term, reduced glacier cover and snow storage will lead to a discharge regime dominated by short-term precipitation events in all seasons, and a reduced influence of the seasonal meltwater discharge peak. The study demonstrates the importance of glacier hypsometry above the present ELA as an influence on catchment hydrological response to potential climate warming.

Operating room discharge after deep neuromuscular block reversed with sugammadex compared with shallow block reversed with neostigmine: a randomized controlled trial.

PubMed

Putz, Laurie; Dransart, Christophe; Jamart, Jacques; Marotta, Maria-Laura; Delnooz, Geraldine; Dubois, Philippe E

2016-12-01

To determine if reversing a deep or moderate block with sugammadex, compared with a shallow block reversed with neostigmine, reduces the time to operating room discharge after surgery and the time spent in the postanesthesia care unit. A randomized controlled trial. Monocentric study performed from February 2011 until May 2012. One hundred consenting women with American Society of Anesthesiologists grade I or II were randomized into 2 groups. Laparoscopic hysterectomy was performed under desflurane general anesthesia. For the neostigmine (N) group, 0.45 mg · kg -1 rocuronium was followed by spontaneous recovery. A 5-mg rescue bolus was administered only if surgical evaluation was unacceptable. At the end of surgery, 50 μg · kg -1 neostigmine with glycopyrrolate was administered. For the sugammadex (S) group, a higher intubating rocuronium dose (0.6 mg · kg -1 ) was followed by 5-mg boluses each time the train-of-four count exceeded 2. Sugammadex (2-4 mg · kg -1 ) was administered to reverse the block. All patients were extubated after obtaining a train-of-four ratio of 0.9. The duration between the end of surgery and operating room discharge and the time spent in the postanesthesia care unit. The time till operating room discharge was shorter and more predictable in group S (9.15±4.28 minutes vs 13.87±11.43 minutes in group N; P=.005). The maximal duration in group S was 22 minutes, compared with 72 minutes in group N. The time spent in the postanesthesia care unit was not significantly different (group S: 47.75±31.77 minutes and group N: 53.43±40.57 minutes; P=.543). Maintaining a deep neuromuscular block during laparoscopic hysterectomy reversed at the end of the procedure with sugammadex enabled a faster and more predictable time till operating room discharge than did the classical combination of a shallower block reversed with neostigmine. Copyright © 2016 Elsevier Inc. All rights reserved.

Multiscale regime shifts and planetary boundaries.

PubMed

Hughes, Terry P; Carpenter, Stephen; Rockström, Johan; Scheffer, Marten; Walker, Brian

2013-07-01

Life on Earth has repeatedly displayed abrupt and massive changes in the past, and there is no reason to expect that comparable planetary-scale regime shifts will not continue in the future. Different lines of evidence indicate that regime shifts occur when the climate or biosphere transgresses a tipping point. Whether human activities will trigger such a global event in the near future is uncertain, due to critical knowledge gaps. In particular, we lack understanding of how regime shifts propagate across scales, and whether local or regional tipping points can lead to global transitions. The ongoing disruption of ecosystems and climate, combined with unprecedented breakdown of isolation by human migration and trade, highlights the need to operate within safe planetary boundaries. Copyright © 2013 Elsevier Ltd. All rights reserved.

Numerical analysis of similarity of barrier discharges in the 0.95 Ne/0.05 Xe mixture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avtaeva, S. V.; Kulumbaev, E. B.

2009-04-15

Established dynamic regimes of similar (with a scale factor of 10) barrier discharges in the 0.95 Ne/0.05 Xe mixture are simulated in a one-dimensional drift-diffusion model. The similarity is examined of barrier discharges excited in gaps of lengths 0.4 and 4 mm at gas pressures of 350 and 35 Torr and dielectric layer thicknesses of 0.2 and 2 mm, the frequencies of the 400-V ac voltage applied to the discharge electrodes being 100 and 10 kHz, respectively.

A self-consistent fluid model for radio-frequency discharges in SiH4-H2 compared to experiments

NASA Astrophysics Data System (ADS)

Nienhuis, G. J.; Goedheer, W. J.; Hamers, E. A. G.; van Sark, W. G. J. H. M.; Bezemer, J.

1997-09-01

experiments. The partial pressures of silane, hydrogen, disilane, and the growth rate of amorphous silicon are compared for various combinations of the operating pressure (10-50 Pa), the power (2.5-10 W), and the frequency (13.56-65 MHz). The model shows good agreement with the experimental data in the dust free α regime. Discharges in the γ' regime, where dust has a significant influence, could not be used to validate the model.

Kinetic description of large-scale low pressure glow discharges

NASA Astrophysics Data System (ADS)

Kortshagen, Uwe; Heil, Brian

1997-10-01

In recent years the so called ``nonlocal approximation'' to the solution of the electron Boltzmann equation has attracted considerable attention as an extremely efficient method for the kinetic modeling of low pressure discharges. However, it appears that modern discharges, which are optimized to provide large-scale plasma uniformity, are explicitly designed to work in a regime, in which the nonlocal approximation is no longer strictly valid. In the presentation we discuss results of a hybrid model, which is based on the natural division of the electron distribution function into a nonlocal body, which is determined by elastic collisions only, and a high energy part which requires a more complete treatment due to the action of inelastic collisions and wall losses of electrons. The method is applied to an inductively coupled low pressure discharge. We discuss the transition from plasma density profiles maximal on the discharge axis to plasma density profiles with off-center maxima, which has been observed in experiments. A positive feedback mechanism involved in this transition is pointed out.

A method for improving predictions of bed-load discharges to reservoirs

USGS Publications Warehouse

Lopes, V.L.; Osterkamp, W.R.; Bravo-Espinosa, M.

2007-01-01

Effective management options for mitigating the loss of reservoir water storage capacity to sedimentation depend on improved predictions of bed-load discharges into the reservoirs. Most predictions of bed-load discharges, however, are based on the assumption that the rates of bed-load sediment availability equal the transport capacity of the flow, ignoring the spatio-temporal variability of the sediment supply. This paper develops a semiquantitative method to characterize bed-load sediment transport in alluvial channels, assuming a channel reach is non-supply limited when the bed-load discharge of a given sediment particle-size class is functionally related to the energy that is available to transport that fraction of the total bed-load. The method was applied to 22 alluvial stream channels in the USA to determine whether a channel reach had a supply-limited or non-supply-limited bed-load transport regime. The non-supply-limited transport regime was further subdivided into two groups on the basis of statistical tests. The results indicated the pattern of bed-load sediment transport in alluvial channels depends on the complete spectrum of sediment particle sizes available for transport rather than individual particle-size fractions represented by one characteristic particle size. The application of the method developed in this paper should assist reservoir managers in selecting bed-load sediment transport equations to improve predictions of bed-load discharge in alluvial streams, thereby significantly increasing the efficiency of management options for maintaining the storage capacity of waterbodies. ?? 2007 Blackwell Publishing Asia Pty Ltd.

Effect of pulsed discharge on the ignition of pulse modulated radio frequency glow discharge at atmospheric pressure

NASA Astrophysics Data System (ADS)

Qiu, Shenjie; Guo, Ying; Han, Qianhan; Bao, Yun; Zhang, Jing; Shi, J. J.

2018-01-01

A pulsed discharge is introduced between two sequential pulse-modulated radio frequency glow discharges in atmospheric helium. The dependence of radio frequency discharge ignition on pulsed discharge intensity is investigated experimentally with the pulse voltage amplitudes of 650, 850, and 1250 V. The discharge characteristics and dynamics are studied in terms of voltage and current waveforms, and spatial-temporal evolution of optical emission. With the elevated pulsed discharge intensity of two orders of magnitude, the ignition of radio frequency discharge is enhanced by reducing the ignition time and achieving the stable operation with a double-hump spatial profile. The ignition time of radio frequency discharge is estimated to be 2.0 μs, 1.5 μs, and 1.0 μs with the pulse voltage amplitudes of 650, 850, and 1250 V, respectively, which is also demonstrated by the spatial-temporal evolution of optical emission at 706 and 777 nm.

Effect of Doppler flow meter position on discharge measurement in surcharged manholes.

PubMed

Yang, Haoming; Zhu, David Z; Liu, Yanchen

2018-02-01

Determining the proper installation location of flow meters is important for accurate measurement of discharge in sewer systems. In this study, flow field and flow regimes in two types of manholes under surcharged flow were investigated using a commercial computational fluid dynamics (CFD) code. The error in measuring the flow discharge using a Doppler flow meter (based on the velocity in a Doppler beam) was then estimated. The values of the corrective coefficient were obtained for the Doppler flow meter at different locations under various conditions. Suggestions for selecting installation positions are provided.

Going with the flow: using species-discharge relationships to forecast losses in fish biodiversity.

PubMed

Xenopoulos, Marguerite A; Lodge, David M

2006-08-01

In response to the scarcity of tools to make quantitative forecasts of the loss of aquatic species from anthropogenic effects, we present a statistical model that relates fish species richness to river discharge. Fish richness increases logarithmically with discharge, an index of habitat space, similar to a species-area curve in terrestrial systems. We apply the species-discharge model as a forecasting tool to build scenarios of changes in riverine fish richness from climate change, water consumption, and other anthropogenic drivers that reduce river discharge. Using hypothetical reductions in discharges (of magnitudes that have been observed in other rivers), we predict that reductions of 20-90% in discharge would result in losses of 2-38% of the fish species in two biogeographical regions in the United States (Lower Ohio-Upper Mississippi and Southeastern). Additional data on the occurrence of specific species relative to specific discharge regimes suggests that fishes found exclusively in high discharge environments (e.g., Shovelnose sturgeon) would be most vulnerable to reductions in discharge. Lag times in species extinctions after discharge reduction provide a window of opportunity for conservation efforts. Applications of the species-discharge model can help prioritize such management efforts among species and rivers.

Trade-off analysis of discharge-desiltation-turbidity and ANN analysis on sedimentation of a combined reservoir-reach system under multi-phase and multi-layer conjunctive releasing operation

NASA Astrophysics Data System (ADS)

Huang, Chien-Lin; Hsu, Nien-Sheng; Wei, Chih-Chiang; Yao, Chun-Hao

2017-10-01

Multi-objective reservoir operation considering the trade-off of discharge-desiltation-turbidity during typhoons and sediment concentration (SC) simulation modeling are the vital components for sustainable reservoir management. The purposes of this study were (1) to analyze the multi-layer release trade-offs between reservoir desiltation and intake turbidity of downstream purification plants and thus propose a superior conjunctive operation strategy and (2) to develop ANFIS-based (adaptive network-based fuzzy inference system) and RTRLNN-based (real-time recurrent learning neural networks) substitute SC simulation models. To this end, this study proposed a methodology to develop (1) a series of multi-phase and multi-layer sediment-flood conjunctive release modes and (2) a specialized SC numerical model for a combined reservoir-reach system. The conjunctive release modes involve (1) an optimization model where the decision variables are multi-phase reduction/scaling ratios and the timings to generate a superior total release hydrograph for flood control (Phase I: phase prior to flood arrival, Phase II/III: phase prior to/subsequent to peak flow) and (2) a combination method with physical limitations regarding separation of the singular hydrograph into multi-layer release hydrographs for sediment control. This study employed the featured signals obtained from statistical quartiles/sediment duration curve in mesh segmentation, and an iterative optimization model with a sediment unit response matrix and corresponding geophysical-based acceleration factors, for efficient parameter calibration. This research applied the developed methodology to the Shihmen Reservoir basin in Taiwan. The trade-off analytical results using Typhoons Sinlaku and Jangmi as case examples revealed that owing to gravity current and re-suspension effects, Phase I + II can de-silt safely without violating the intake's turbidity limitation before reservoir discharge reaches 2238 m3/s; however

Oil Discharge Reporting Requirements

EPA Pesticide Factsheets

If a facility or vessel discharges oil to navigable waters or adjoining shorelines, the owner/operator is required to follow certain federal reporting requirements. This fact sheet outlines those reporting requirements.

Note: Arc discharge plasma source with plane segmented LaB{sub 6} cathode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akhmetov, T. D., E-mail: t.d.akhmetov@inp.nsk.su; Davydenko, V. I.; Ivanov, A. A.

2016-05-15

A plane cathode composed of close-packed hexagonal LaB{sub 6} (lanthanum hexaboride) segments is described. The 6 cm diameter circular cathode is heated by radiation from a graphite foil flat spiral. The cathode along with a hollow copper anode is used for the arc discharge plasma production in a newly developed linear plasma device. A separately powered coil located around the anode is used to change the magnetic field strength and geometry in the anode region. Different discharge regimes were realized using this coil.

On the Mechanism of Maintenance and Instability of the Overvoltage Low-Pressure Discharge Forming a High-Current Runaway Electron Beam

NASA Astrophysics Data System (ADS)

Akishev, Yu. S.; Balakirev, A. A.; Karal'nik, V. B.; Medvedev, M. A.; Petryakov, A. V.; Trushkin, N. I.; Shafikov, A. G.

2017-12-01

Results of experiments on the study of dynamics of an overvoltage discharge at the low pressure p = 0.5-2.5 Torr up to its transition to the high-current low-voltage regime are presented, and the instability mechanism leading to a sharp voltage drop across the discharge is suggested.

Coupling Effects of Unsteady River Discharges and Wave Conditions on Mouth Bar Formation

NASA Astrophysics Data System (ADS)

Gao, W.; Shao, D.; Zheng Bing, W.; Yang, W.; Sun, T.; Cui, B.

2017-12-01

As a key morphological unit at delta front, the evolution of mouth bar is of critical importance to channel bifurcation and the formation of deltaic distributaries, and therefore have received wide attention, primarily using numerical modelling approaches. Notably, the existing numerical modelling studies were mostly carried out under the assumption that most of the sediments are delivered to the ocean during bankfull discharge stages, so is the most significant deltaic morphological evolution, and hence periods of relatively low river discharge were `safely' neglected, leaving out the effects of unsteadiness of river discharge on the relevant morphodynamic processes altogether. However, the above assumption is worth reviewing in the context of combined fluvial and marine forcing as the relative wave strength has been repeatedly proved to be a critical parameter in estuarine-deltaic morphodynamics. In natural deltas, the period of high river discharge may or may not coincide with the occurrence of maximum wave strength, which further complicates their coupling effects. To assess the coupling effects of unsteady river discharges and wave conditions on mouth bar formation, numerical experiments using Delft3D-SWAN were conducted in this study. A host of combined high-and-low river discharges coupled with varying wave strengths were assumed to mimic the natural variability. Numerical simulation results suggest the existence of three regimes for mouth bar formation, namely, nonexistence of mouth bar (G1), formation of ephemeral mouth bar (G2) and formation of stable mouth bar (G3), which were dictated by the relative wave strength during both onset and reworking stages as well as the reworking time. Implications of the mouth bar formation regimes on delta distributary networks were also discussed. The findings have implications for coastal management at estuaries and deltas such as erosion prevention and mitigation, water and sediment regulation scheme, etc.

Direct current plasma jet at atmospheric pressure operating in nitrogen and air

NASA Astrophysics Data System (ADS)

Deng, X. L.; Nikiforov, A. Yu.; Vanraes, P.; Leys, Ch.

2013-01-01

An atmospheric pressure direct current (DC) plasma jet is investigated in N2 and dry air in terms of plasma properties and generation of active species in the active zone and the afterglow. The influence of working gases and the discharge current on plasma parameters and afterglow properties are studied. The electrical diagnostics show that discharge can be sustained in two different operating modes, depending on the current range: a self-pulsing regime at low current and a glow regime at high current. The gas temperature and the N2 vibrational temperature in the active zone of the jet and in the afterglow are determined by means of emission spectroscopy, based on fitting spectra of N2 second positive system (C3Π-B3Π) and the Boltzmann plot method, respectively. The spectra and temperature differences between the N2 and the air plasma jet are presented and analyzed. Space-resolved ozone and nitric oxide density measurements are carried out in the afterglow of the jet. The density of ozone, which is formed in the afterglow of nitrogen plasma jet, is quantitatively detected by an ozone monitor. The density of nitric oxide, which is generated only in the air plasma jet, is determined by means of mass-spectroscopy techniques.

Generation of warm dense matter using an argon based capillary discharge laser

NASA Astrophysics Data System (ADS)

Rossall, A. K.; Tallents, G. J.

2015-06-01

Argon based capillary discharge lasers operating in the extreme ultra violet (EUV) at 46.9 nm with output up to 0.5 mJ energy per pulse and repetition rates up to 10 Hz are capable of focused irradiances of 109-1012 W cm-2 and can be used to generate plasma in the warm dense matter regime by irradiating solid material. To model the interaction between such an EUV laser and solid material, the 2D radiative-hydrodynamic code POLLUX has been modified to include absorption via direct photo-ionisation, a super-configuration model to describe the ionization-dependent electronic configurations and a calculation of plasma refractive indices for ray tracing of the incident EUV laser radiation. A simulation study is presented, demonstrating how capillary discharge lasers of 1200 ps pulse duration can be used to generate warm dense matter at close to solid densities with temperatures of a few eV and energy densities up to 1 × 105 J cm-3. Plasmas produced by EUV laser irradiation are shown to be useful for examining the properties of warm dense matter as, for example, plasma emission is not masked by hotter, less dense plasma emission that occurs with visible/infra-red laser target irradiation.

A thermal profile method to identify potential ground-water discharge areas and preferred salmonid habitats for long river reaches

USGS Publications Warehouse

Vaccaro, J.J.; Maloy, K.J.

2006-01-01

The thermal regime of riverine systems is a major control on aquatic ecosystems. Ground water discharge is an important abiotic driver of the aquatic ecosystem because it provides preferred thermal structure and habitat for different types of fish at different times in their life history. In large diverse river basins with an extensive riverine system, documenting the thermal regime and ground-water discharge is difficult and problematic. A method was developed to thermally profile long (5-25 kilometers) river reaches by towing in a Lagrangian framework one or two probes that measure temperature, depth, and conductivity. One probe is towed near the streambed and, if used, a second probe is towed near the surface. The probes continuously record data at 1-3-second intervals while a Global Positioning System logs spatial coordinates. The thermal profile provides valuable information about spatial and temporal variations in habitat, and, notably, indicates ground-water discharge areas. This method was developed and tested in the Yakima River Basin, Washington, in summer 2001 during low flows in an extreme drought year. The temperature profile comprehensively documents the longitudinal distribution of a river's temperature regime that cannot be captured by fixed station data. The example profile presented exhibits intra-reach diversity that reflects the many factors controlling the temperature of a parcel of water as it moves downstream. Thermal profiles provide a new perspective on riverine system temperature regimes that represent part of the aquatic habitat template for lotic community patterns.

TREHS: An open-access software tool for investigating and evaluating temporary river regimes as a first step for their ecological status assessment.

PubMed

Gallart, Francesc; Cid, Núria; Latron, Jérôme; Llorens, Pilar; Bonada, Núria; Jeuffroy, Justin; Jiménez-Argudo, Sara-María; Vega, Rosa-María; Solà, Carolina; Soria, Maria; Bardina, Mònica; Hernández-Casahuga, Antoni-Josep; Fidalgo, Aránzazu; Estrela, Teodoro; Munné, Antoni; Prat, Narcís

2017-12-31

When the regime of a river is not perennial, there are four main difficulties with the use of hydrographs for assessing hydrological alteration: i) the main hydrological features relevant for biological communities are not quantitative (discharges) but qualitative (phases such as flowing water, stagnant pools or lack of surface water), ii) stream flow records do not inform on the temporal occurrence of stagnant pools, iii) as most of the temporary streams are ungauged, their regime has to be evaluated by alternative methods such as remote sensing or citizen science, and iv) the biological quality assessment of the ecological status of a temporary stream must follow a sampling schedule and references adapted to the flow- pool-dry regime. To overcome these challenges within an operational approach, the freely available software tool TREHS has been developed within the EU LIFE TRIVERS project. This software permits the input of information from flow simulations obtained with any rainfall-runoff model (to set an unimpacted reference stream regime) and compares this with the information obtained from flow gauging records (if available) and interviews with local people, as well as instantaneous observations by individuals and interpretation of ground-level or aerial photographs. Up to six metrics defining the permanence of water flow, the presence of stagnant pools and their temporal patterns of occurrence are used to determine natural and observed river regimes and to assess the degree of hydrological alteration. A new regime classification specifically designed for temporary rivers was developed using the metrics that measure the relative permanence of the three main phases: flow, disconnected pools and dry stream bed. Finally, the software characterizes the differences between the natural and actual regimes, diagnoses the hydrological status (degree of hydrological alteration), assesses the significance and robustness of the diagnosis and recommends the best periods

Effects of discharge chamber length on the negative ion generation in volume-produced negative hydrogen ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Kyoung-Jae; Jung, Bong-Ki; An, YoungHwa

2014-02-15

In a volume-produced negative hydrogen ion source, control of electron temperature is essential due to its close correlation with the generation of highly vibrationally excited hydrogen molecules in the heating region as well as the generation of negative hydrogen ions by dissociative attachment in the extraction region. In this study, geometric effects of the cylindrical discharge chamber on negative ion generation via electron temperature changes are investigated in two discharge chambers with different lengths of 7.5 cm and 11 cm. Measurements with a radio-frequency-compensated Langmuir probe show that the electron temperature in the heating region is significantly increased by reducingmore » the length of the discharge chamber due to the reduced effective plasma size. A particle balance model which is modified to consider the effects of discharge chamber configuration on the plasma parameters explains the variation of the electron temperature with the chamber geometry and gas pressure quite well. Accordingly, H{sup −} ion density measurement with laser photo-detachment in the short chamber shows a few times increase compared to the longer one at the same heating power depending on gas pressure. However, the increase drops significantly as operating gas pressure decreases, indicating increased electron temperatures in the extraction region degrade dissociative attachment significantly especially in the low pressure regime. It is concluded that the increase of electron temperature by adjusting the discharge chamber geometry is efficient to increase H{sup −} ion production as long as low electron temperatures are maintained in the extraction region in volume-produced negative hydrogen ion sources.« less

A gas discharge lamp for the extreme ultraviolet.

PubMed

Nicholson, A J

1970-05-01

A gas discharge lamp is described suitable for producing the many-lined spectrum of hydrogen (85-160 nm) and the Hopfield continuum in helium (60-100 nm). It was designed for use with a window-less monochromator to study photoionization and operates at pressures below 50 Torr. The hydrogen lamp has a mode of operation which concentrates the discharge into the monochromator entrance slit.

Investigation on discharge characteristics of a coaxial dielectric barrier discharge reactor driven by AC and ns power sources

NASA Astrophysics Data System (ADS)

Qian, WANG; Feng, LIU; Chuanrun, MIAO; Bing, YAN; Zhi, FANG

2018-03-01

A coaxial dielectric barrier discharge (DBD) reactor with double layer dielectric barriers has been developed for exhaust gas treatment and excited either by AC power or nanosecond (ns) pulse to generate atmospheric pressure plasma. The comparative study on the discharge characteristics of the discharge uniformity, power deposition, energy efficiency, and operation temperature between AC and ns pulsed coaxial DBD is carried out in terms of optical and electrical characteristics and operation temperature for optimizing the coaxial DBD reactor performance. The voltages across the air gap and dielectric layer and the conduction and displacement currents are extracted from the applied voltages and measured currents of AC and ns pulsed coaxial DBDs for the calculation of the power depositions and energy efficiencies through an equivalent electrical model. The discharge uniformity and operating temperature of the coaxial DBD reactor are monitored and analyzed by optical images and infrared camera. A heat conduction model is used to calculate the temperature of the internal quartz tube. It is found that the ns pulsed coaxial DBD has a much higher instantaneous power deposition in plasma, a lower total power consumption, and a higher energy efficiency compared with that excited by AC power and is more homogeneous and stable. The temperature of the outside wall of the AC and ns pulse excited coaxial DBD reaches 158 °C and 64.3 °C after 900 s operation, respectively. The experimental results on the comparison of the discharge characteristics of coaxial DBDs excited by different powers are significant for understanding of the mechanism of DBDs, reducing energy loss, and optimizing the performance of coaxial DBD in industrial applications.

Supersonic CO electric-discharge lasers

NASA Technical Reports Server (NTRS)

Hason, R. K.; Mitchner, M.; Stanton, A.

1975-01-01

Laser modeling activity is described which involved addition of an option allowing N2 as a second diatomic gas. This option is now operational and a few test cases involving N2/CO mixtures were run. Results from these initial test cases are summarized. In the laboratory, a CW double-discharge test facility was constructed and tested. Features include: water-cooled removable electrodes, O-ring construction to facilitate cleaning and design modifications, increased discharge length, and addition of a post-discharge observation section. Preliminary tests with this facility using N2 yielded higher power loadings than obtained in the first-generation facility. Another test-section modification, recently made and as yet untested, will permit injection of secondary gases into the cathode boundary layer. The objective will be to vary and enhance the UV emission spectrum from the auxiliary discharge, thereby influencing the level of photoionization in the main discharge region.

Radiation effects on ETFE polymer exposed to glow discharge

NASA Astrophysics Data System (ADS)

Minamisawa, Renato Amaral; Abidzina, Volha; de Almeida, Adelaide; Budak, Satilmis; Tereshko, I.; Elkin, I.; Ila, Daryush

2007-08-01

The polymer ethylenetetrafluoroethylene (ETFE) is composed of alternating ethylene and tetrafluoroethylene segments. Because it has applications in areas such as medical physics and industrial coatings, there is a great interest in surface modification studies of ETFE polymer. When this material is exposed to ionizing radiation it suffers damage that depends on the type, energy and intensity of the irradiation. In order to determine the radiation damage mechanism from exposure to low voltage plasma, ETFE films were exposed to residual gas plasma in glow discharge regime to a fluence of 2 × 1017 ions/cm2. Irradiated films were analyzed with optical absorption photospectrometry, Fourier transform infrared (FTIR) and Raman spectroscopy to determine the chemical nature of the structural changes caused by low energy glow discharge.

Device for generation of pulsed corona discharge

DOEpatents

Gutsol, Alexander F [San Ramon, CA; Fridman, Alexander [Marlton, NJ; Blank, Kenneth [Philadelphia, PA; Korobtsev, Sergey [Moscow, RU; Shiryaevsky, Valery [Moscow, RU; Medvedev, Dmitry [Moscow, RU

2012-05-08

The invention is a method and system for the generation of high voltage, pulsed, periodic corona discharges capable of being used in the presence of conductive liquid droplets. The method and system can be used, for example, in different devices for cleaning of gaseous or liquid media using pulsed corona discharge. Specially designed electrodes and an inductor increase the efficiency of the system, permit the plasma chemical oxidation of detrimental impurities, and increase the range of stable discharge operations in the presence of droplets of water or other conductive liquids in the discharge chamber.

Parametric investigation of enclosed keeper discharge characteristics

NASA Technical Reports Server (NTRS)

Sheheen, T. W.; Finke, R. C.

1973-01-01

Volt-ampere discharge characteristics of an enclosed keeper hollow cathode discharge were measured as a function of the mercury flow rate and external circuit impedance. Discharge currents were varied from 0 to 1 ampere and voltages were 7 to 39 volts. Batteries and a vacuum tube control circuit were used to obtain characteristics curves that were independent of power supply impedance. Variation of the neutral flow results in changes in the discharge which interact with the impedance of the external circuit, and under some conditions, give rise to multiple operating points.

High-repetition-rate short-pulse gas discharge.

PubMed

Tulip, J; Seguin, H; Mace, P N

1979-09-01

A high-average-power short-pulse gas discharge is described. This consists of a volume-preionized transverse discharge of the type used in gas lasers driven by a Blumlein energy storage circuit. The Blumlein circuit is fabricated from coaxial cable, is pulse-charged from a high-repetition-rate Marx-bank generator, and is switched by a high-repetition-rate segmented rail gap. The operation of this discharge under conditions typical of rare-gas halide lasers is described. A maximum of 900 pps was obtained, giving a power flow into the discharge of 30 kW.

Numerical analysis of effects of ion-neutral collision processes on RF ICP discharge

NASA Astrophysics Data System (ADS)

Nishida, K.; Mattei, S.; Lettry, J.; Hatayama, A.

2018-01-01

The discharge process of a radiofrequency (RF) inductively coupled plasma (ICP) has been modeled by an ElectroMagnetic Particle-in-Cell Monte Carlo Collision method (EM PIC-MCC). Although the simulation had been performed by our previous model to investigate the discharge mode transition of the RF ICP from a kinetic point of view, the model neglected the collision processes of ions (H+ and H2+) with neutral particles. In this study, the RF ICP discharge process has been investigated by the latest version of the model which takes the ion-neutral collision processes into account. The basic characteristics of the discharge mode transition provided by the previous model have been verified by the comparison between the previous and present results. As for the H-mode discharge regime, on the other hand, the ion-neutral collisions play an important role in evaluating the growth of the plasma. Also, the effect of the ion-neutral collisions on the kinetic feature of the plasma has been investigated, which has highlighted the importance of kinetic perspective for modeling the RF ICP discharge.

Sterilization/disinfection using reduced-pressure plasmas: some differences between direct exposure of bacterial spores to a discharge and their exposure to a flowing afterglow

NASA Astrophysics Data System (ADS)

Moisan, M.; Levif, P.; Séguin, J.; Barbeau, J.

2014-07-01

The use of plasma for sterilization or disinfection offers a promising alternative to conventional steam or chemical approaches. Plasma can operate at temperatures less damaging to some heat-sensitive medical devices and, in contrast to chemicals, can be non-toxic and non-polluting for the operator and the environment, respectively. Direct exposure to the gaseous discharge (comprising an electric field and ions/electrons) or exposure to its afterglow (no E-field) can both be envisaged a priori, since these two methods can achieve sterility. However, important issues must be considered besides the sterility goal. Direct exposure to the discharge, although yielding a faster inactivation of microorganisms, is shown to be potentially more aggressive to materials and sometimes subjected to the shadowing effect that precludes the sterilization of complex-form items. These two drawbacks can be successfully minimized with an adequate flowing-afterglow exposure. Most importantly, the current paper shows that direct exposure to the discharge can lead to the dislodgment and release of viable microorganisms from their substratum. Such a phenomenon could be responsible for the recontamination of sterilized devices as well as possible contamination of the ambient surroundings, additionally yielding an erroneous over-appreciation of the inactivation efficiency. The operation of the N2-O2 flowing afterglow system being developed in our group is such that there are no ions and electrons left in the process chamber (late-afterglow regime) in full contrast with their presence in the discharge. The dislodgment and release of spores could be attributed, based on the literature, to their electrostatic charging by electrons, leading to an (outward) electrostatic stress that exceeds the adhesion of the spores on their substrate.

Self-pulsing discharge of a plasma brush operated in atmospheric-pressure argon

NASA Astrophysics Data System (ADS)

Li, Xuechen; Liu, Runfu; Jia, Pengying; Bao, Wenting; Shang, Yong

2013-06-01

A plasma brush excited by DC voltage is developed with argon as working gas in the ambient air. The time evolution of the discharge current, the light emission, and the sustaining voltage are analyzed under different conditions. The self-pulsing phenomenon of the discharge is observed with oscillated voltage and intermittent current. The self-pulsing frequency ranges from several tens hertz to several hundred hertz depending on the output power and the gas flow rate. It increases with the increasing of the gas flow rate, while it decreases as the output power increases. The phenomenon is explained qualitatively based on a spatially resolved measurement about the discharge.

Flywheel Charge/Discharge Control Developed

NASA Technical Reports Server (NTRS)

Beach, Raymond.F.; Kenny, Barbara H.

2001-01-01

A control algorithm developed at the NASA Glenn Research Center will allow a flywheel energy storage system to interface with the electrical bus of a space power system. The controller allows the flywheel to operate in both charge and discharge modes. Charge mode is used to store additional energy generated by the solar arrays on the spacecraft during insolation. During charge mode, the flywheel spins up to store the additional electrical energy as rotational mechanical energy. Discharge mode is used during eclipse when the flywheel provides the power to the spacecraft. During discharge mode, the flywheel spins down to release the stored rotational energy.

33 CFR 159.315 - Sewage and graywater discharge record book.

Code of Federal Regulations, 2014 CFR

2014-07-01

... record book. 159.315 Section 159.315 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... by Cruise Vessel Operations § 159.315 Sewage and graywater discharge record book. (a) While operating... and Graywater Discharge Record Book with the vessel's name and official number listed on the front...

33 CFR 159.315 - Sewage and graywater discharge record book.

Code of Federal Regulations, 2010 CFR

2010-07-01

... record book. 159.315 Section 159.315 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... by Cruise Vessel Operations § 159.315 Sewage and graywater discharge record book. (a) While operating... and Graywater Discharge Record Book with the vessel's name and official number listed on the front...

33 CFR 159.315 - Sewage and graywater discharge record book.

Code of Federal Regulations, 2013 CFR

2013-07-01

... record book. 159.315 Section 159.315 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... by Cruise Vessel Operations § 159.315 Sewage and graywater discharge record book. (a) While operating... and Graywater Discharge Record Book with the vessel's name and official number listed on the front...

33 CFR 159.315 - Sewage and graywater discharge record book.

Code of Federal Regulations, 2012 CFR

2012-07-01

... record book. 159.315 Section 159.315 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... by Cruise Vessel Operations § 159.315 Sewage and graywater discharge record book. (a) While operating... and Graywater Discharge Record Book with the vessel's name and official number listed on the front...

33 CFR 159.315 - Sewage and graywater discharge record book.

Code of Federal Regulations, 2011 CFR

2011-07-01

... record book. 159.315 Section 159.315 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... by Cruise Vessel Operations § 159.315 Sewage and graywater discharge record book. (a) While operating... and Graywater Discharge Record Book with the vessel's name and official number listed on the front...

Investigation of a single barrier discharge in submillimeter air gaps. Nonuniform field

NASA Astrophysics Data System (ADS)

Bondarenko, P. N.; Emel'yanov, O. A.; Shemet, M. V.

2014-08-01

Pulse characteristics of single barrier discharges as well as parameters of charges accumulated on the surface of a dielectric under the atmospheric pressure in the "needle-(0.1-2.0)-mm air gap-polymer barrier-plane" system are investigated. It is found experimentally that for the positive polarity of the needle, the voltage for the discharge initiation is higher than in the case of the negative polarity by ˜25-35%. The reversal of the needle polarity from negative to positive increases the amplitude of the discharge current and the accumulated surface charge by ˜1.5-3 times. For the positive polarity of the needle, the discharge is governed by a streamer mechanism, while for the negative polarity, the discharge is initiated by the formation of a single Trichel pulse. The single pulse regime is observed for the discharge current up to a certain electrode gap d CR. For the positive needle and for air gap width d air > d CR ≈ 1.5 mm, a multipulse burst corona is formed, while for the negative needle and d air > d CR ≈ 0.9 mm, a damped sequence of Trichel pulses evolves in the system.

Investigation of the laser pumping power impact on the operating regimes of a laser passively Q-switched by a saturated absorber

NASA Astrophysics Data System (ADS)

Benarab, Mustapha; Mokdad, Rabah; Djellout, Hocine; Benfdila, Arezki; Lamrous, Omar; Meyrueis, Patrick

2011-09-01

We have adapted the point model for the study of an all-fiber laser doped with Nd3+ and Q-switched by a saturable fiber absorber doped with Cr4+. Calculations of the output power of the 1084 nm laser are considered as a function of the pump power supplied by a 790 nm laser diode. The analysis of the simulation results reveals the existence of pulsed, sinusoidal, and dc operating regimes.

33 CFR 157.31 - Discharges: Chemical additives.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Discharges: Chemical additives. 157.31 Section 157.31 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... OIL IN BULK Vessel Operation § 157.31 Discharges: Chemical additives. No person may use a chemical...

33 CFR 157.31 - Discharges: Chemical additives.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Discharges: Chemical additives. 157.31 Section 157.31 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... OIL IN BULK Vessel Operation § 157.31 Discharges: Chemical additives. No person may use a chemical...

21 CFR 1250.93 - Discharge of wastes.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Discharge of wastes. 1250.93 Section 1250.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.93 Discharge of wastes. Vessels operating...

33 CFR 157.31 - Discharges: Chemical additives.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Discharges: Chemical additives. 157.31 Section 157.31 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... OIL IN BULK Vessel Operation § 157.31 Discharges: Chemical additives. No person may use a chemical...

33 CFR 157.31 - Discharges: Chemical additives.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Discharges: Chemical additives. 157.31 Section 157.31 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... OIL IN BULK Vessel Operation § 157.31 Discharges: Chemical additives. No person may use a chemical...

33 CFR 157.31 - Discharges: Chemical additives.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Discharges: Chemical additives. 157.31 Section 157.31 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... OIL IN BULK Vessel Operation § 157.31 Discharges: Chemical additives. No person may use a chemical...

21 CFR 1250.93 - Discharge of wastes.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Discharge of wastes. 1250.93 Section 1250.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.93 Discharge of wastes. Vessels operating...

A pulser-sustainer carbon monoxide electric-discharge supersonic laser

NASA Technical Reports Server (NTRS)

Monson, D. J.; Srinivasan, G.

1977-01-01

Operation of a CW CO electric-discharge supersonic laser with a pulser-sustainer discharge is described. High-power operation as well as independent control over electron energy and density are demonstrated. Maximum input power achieved to date is 100 kW. The maximum output power is 6 kW or 10% of the sustainer positive-column power. Much improved performance appears possible.

Electrochemical reaction mechanisms under various charge-discharge operating conditions for Li1.2Ni0.13Mn0.54Co0.13O2 in a lithium-ion battery

NASA Astrophysics Data System (ADS)

Konishi, Hiroaki; Hirano, Tatsumi; Takamatsu, Daiko; Gunji, Akira; Feng, Xiaoliang; Furutsuki, Sho; Okumura, Takefumi; Terada, Shohei; Tamura, Kazuhisa

2018-06-01

The potential in each state of charge (SOC) during charging of Li1.2Ni0.13Mn0.54Co0.13O2 is higher than that during discharging. In other words, the potential hysteresis occurs between charging and discharging. Furthermore, the potential in each SOC changes according to the charge-discharge operating conditions, indicating that the charge-discharge reaction mechanism is also affected. To clarify the effect of charge-discharge operating conditions on the electrochemical reaction, Li1.2Ni0.13Mn0.54Co0.13O2 was charged and discharged under various charge-discharge operating ranges, and open-circuit potential (OCP), crystal structure, and oxidation states of the transition metals were evaluated by electrochemical measurement, X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS). These results indicate that OCP, lattice parameters, and oxidation states of the transition metals of Li1.2Ni0.13Mn0.54Co0.13O2 in each SOC are not constant. The XRD results indicate that two phases, namely, LiNi0.33Mn0.33Co0.33O2-like and Li2MnO3-like, exist in Li1.2Ni0.13Mn0.54Co0.13O2. For the LiNi0.33Mn0.33Co0.33O2-like phase, the relationship between OCP, lattice parameters, and oxidation states of the transition metals in each SOC is not affected by the charge-discharge operating conditions, indicating that extraction and insertion of lithium ions for the LiNi0.33Mn0.33Co0.33O2-like phase progresses at almost the same potential. Although the extraction and insertion of lithium ions for the Li2MnO3-like phase progresses at almost the same potential in the low-SOC region, the OCP and lattice parameter in each SOC in the high-SOC region are not constant. Therefore, the extraction of lithium ions from the Li2MnO3-like phase in the high-SOC region causes the potential hysteresis of Li1.2Ni0.13Mn0.54Co0.13O2.

Sediment discharge from highway construction near Port Carbon, Pennsylvania

USGS Publications Warehouse

Helm, Robert E.

1978-01-01

About 16,000 tons of suspended-sediment was discharged from the basin during the construction. The highway construction produced about 8,000 tons or 50 percent of the total sediment discharge. Steep slopes, the availability of fine coal wastes, coal-washing operations, and other land uses in the basin were responsible for most of the remaining sediment discharge. Seventy percent of the total suspended-sediment discharge occurred during eight storms.

Thermodynamic analysis of journal bearings operating under steady state loading in laminar regime. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Khonsari, M. M.

1983-01-01

Thermohydrodynamic effects in journal bearings operating under steady load in laminar regime are investigated. An analytical model for the finite and infinitely long journal bearings is formulated. The model includes correction factors for the cavitation effects in the unloaded region of the bearing and the mixing of the recirculating oil and supply oil at the oil inlet. A finite difference computer program is developed to numerically solve the governing equations of the continuity, Reynolds, energy, Laplace heat conduction, and a viscosity-temperature relation simultaneously. The program includes a numerical technique for obtaining an isothermal shaft temperature. The numerical results of temperature distribution and the heat effects on the bearing load carrying capacity agree closely with those of experimental findings. Several different sets of simpler boundary conditions for the energy equation are studied.

Theory of beam plasma discharge

NASA Technical Reports Server (NTRS)

Papadopoulos, K.

1982-01-01

The general theory of beam plasma discharge (BPD) is discussed in relation to space and laboratory beam injection situations. An important concept introduced is that even when beam plasma instabilities are excited, there are two regime of BPD with radically different observational properties. They are described here as BPD with either classical or anomalous energy depositions. For high pressures or low altitudes, the classical is expected to dominate. For high altitudes and laboratory experiments, where the axial system size is less than lambda sub en, no BPD will be triggered unless the unstable waves are near the ambient plasma frequency and their amplitudes at saturation are large enough to create suprathermal tails by collapsing.

An Apparatus for Measuring Rates of Discharge of a Fuel-Injection System

NASA Technical Reports Server (NTRS)

Dutee, Francis J

1941-01-01

A portable apparatus for rapidly determining rates of discharge of a fuel-injection system is described. Satisfactory operation of this apparatus with injection-pump speeds up to 2400 r.p.m was obtained. Rate-of-discharge tests were made with several cam-plunger-valve injection systems with long injection tubes. A check valve designed to reduce secondary discharges was tested. This check valve was operated with injection-pump speeds up to 2400 r.p.m without the occurrence of large secondary discharges.

Cross-scale analysis of fire regimes

Treesearch

Donald A. Falk; Carol Miller; Donald McKenzie; Anne E. Black

2007-01-01

Cross-scale spatial and temporal perspectives are important for studying contagious landscape disturbances such as fire, which are controlled by myriad processes operating at different scales. We examine fire regimes in forests of western North America, focusing on how observed patterns of fire frequency change across spatial scales. To quantify changes in fire...

40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Rather than assign one a rank of 2 and the other a rank of 3, the average of 2 and 3 (i.e., 2.5) is given... baseline and monitoring (i.e., n = 12 and m = 12), the critical value C is 99. (f) Compare C to Sn. If Sn... Discharges at Remining Operations I. General Procedure Requirements a. This appendix presents the procedures...

40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Rather than assign one a rank of 2 and the other a rank of 3, the average of 2 and 3 (i.e., 2.5) is given... baseline and monitoring (i.e., n = 12 and m = 12), the critical value C is 99. (f) Compare C to Sn. If Sn... Discharges at Remining Operations I. General Procedure Requirements a. This appendix presents the procedures...

Influence of the voltage waveform during nanocomposite layer deposition by aerosol-assisted atmospheric pressure Townsend discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Profili, J.; Département de Physique, Université de Montréal, Montréal, Québec H3C 3J7; Levasseur, O.

2016-08-07

This work examines the growth dynamics of TiO{sub 2}-SiO{sub 2} nanocomposite coatings in plane-to-plane Dielectric Barrier Discharges (DBDs) at atmospheric pressure operated in a Townsend regime using nebulized TiO{sub 2} colloidal suspension in hexamethyldisiloxane as the growth precursors. For low-frequency (LF) sinusoidal voltages applied to the DBD cell, with voltage amplitudes lower than the one required for discharge breakdown, Scanning Electron Microscopy of silicon substrates placed on the bottom DBD electrode reveals significant deposition of TiO{sub 2} nanoparticles (NPs) close to the discharge entrance. On the other hand, at higher frequencies (HF), the number of TiO{sub 2} NPs deposited stronglymore » decreases due to their “trapping” in the oscillating voltage and their transport along the gas flow lines. Based on these findings, a combined LF-HF voltage waveform is proposed and used to achieve significant and spatially uniform deposition of TiO{sub 2} NPs across the whole substrate surface. For higher voltage amplitudes, in the presence of hexamethyldisiloxane and nitrous oxide for plasma-enhanced chemical vapor deposition of inorganic layers, it is found that TiO{sub 2} NPs become fully embedded into a silica-like matrix. Similar Raman spectra are obtained for as-prepared TiO{sub 2} NPs and for nanocomposite TiO{sub 2}-SiO{sub 2} coating, suggesting that plasma exposure does not significantly alter the crystalline structure of the TiO{sub 2} NPs injected into the discharge.« less

Use of flumes in measuring discharge

USGS Publications Warehouse

Kilpatrick, F.A.; Schneider, V.R.

1983-01-01

Flumes for measuring discharge are usually of two general groups-critical-flow flumes and supercritical-flow flumes. In this chapter, the underlying design principles for each group are discussed; the most commonly used flumes are described and their discharge ratings presented. There is also discussion of considerations in choosing and fitting the appropriate flume for a given situation as well as flume construction techniques and operational experiences.

The path to COVIS: A review of acoustic imaging of hydrothermal flow regimes

NASA Astrophysics Data System (ADS)

Bemis, Karen G.; Silver, Deborah; Xu, Guangyu; Light, Russ; Jackson, Darrell; Jones, Christopher; Ozer, Sedat; Liu, Li

2015-11-01

Acoustic imaging of hydrothermal flow regimes started with the incidental recognition of a plume on a routine sonar scan for obstacles in the path of the human-occupied submersible ALVIN. Developments in sonar engineering, acoustic data processing and scientific visualization have been combined to develop technology which can effectively capture the behavior of focused and diffuse hydrothermal discharge. This paper traces the development of these acoustic imaging techniques for hydrothermal flow regimes from their conception through to the development of the Cabled Observatory Vent Imaging Sonar (COVIS). COVIS has monitored such flow eight times a day for several years. Successful acoustic techniques for estimating plume entrainment, bending, vertical rise, volume flux, and heat flux are presented as is the state-of-the-art in diffuse flow detection.

RF assisted Glow Discharge Condition experiment for SST-1 Tokamak

NASA Astrophysics Data System (ADS)

Raval, Dilip; Khan, Ziauddin; George, Siju; Dhanani, Kalpeshkumar R.; Paravastu, Yuvakiran; Semwal, Pratibha; Thankey, Prashant; Shoaib Khan, Mohammad; Kakati, Bharat; Pradhan, Subrata

2017-04-01

Impurity control reduces the radiation loss from plasma and hence enhances the plasma operation. Oxygen and water vapors are the most common impurities in tokamak devices. Water vapour can be reduced with extensive baking while in order to have a significant reduction in oxygen it is necessary to use glow discharge condition (GDC). RF assisted glow discharge cleaning system will be implemented to remove low z impurities at PFC installed SST-1 vacuum vessel. A RF assisted Glow discharge conditioning is studied at laboratory to find the optimum operating parameters in a view to implement at SST-1 tokamak. Helium is used as a fuel gas in the present experiment. It is observed that the ultimate impurity level is reduced significantly below to the accepted level for plasma operation after RF assisted GDC. The experimental findings of RF assisted Glow discharge conditioning is discussed in details in this paper.

Discharge reliability in ablative pulsed plasma thrusters

NASA Astrophysics Data System (ADS)

Wu, Zhiwen; Sun, Guorui; Yuan, Shiyue; Huang, Tiankun; Liu, Xiangyang; Xie, Kan; Wang, Ningfei

2017-08-01

Discharge reliability is typically neglected in low-ignition-cycle ablative pulsed plasma thrusters (APPTs). In this study, the discharge reliability of an APPT is assessed analytically and experimentally. The goals of this study are to better understand the ignition characteristics and to assess the accuracy of the analytical method. For each of six sets of operating conditions, 500 tests of a parallel-plate APPT with a coaxial semiconductor spark plug are conducted. The discharge voltage and current are measured with a high-voltage probe and a Rogowski coil, respectively, to determine whether the discharge is successful. Generally, the discharge success rate increases as the discharge voltage increases, and it decreases as the electrode gap and the number of ignitions increases. The theoretical analysis and the experimental results are reasonably consistent. This approach provides a reference for designing APPTs and improving their stability.

XeCl Avalanche discharge laser employing Ar as a diluent

DOEpatents

Sze, Robert C.

1981-01-01

A XeCl avalanche discharge exciplex laser which uses a gaseous lasing starting mixture of: (0.2%-0.4% chlorine donor/2.5%-10% Xe/97.3%-89.6% Ar). The chlorine donor normally comprises HCl but can also comprise CCl.sub.4 BCl.sub.3. Use of Ar as a diluent gas reduces operating pressures over other rare gas halide lasers to near atmospheric pressure, increases output lasing power of the XeCl avalanche discharge laser by 30% to exceed KrF avalanche discharge lasing outputs, and is less expensive to operate.

Impurity confinement and transport in high confinement regimes without edge localized modes on DIII-D [Impurity confinement and transport in high confinement regimes without ELMs on DIII-D

DOE PAGES

Grierson, Brian A.; Burrell, Keith H.; Nazikian, Raffi M.; ...

2015-04-17

Here, impurity transport in the DIII-D tokamak is investigated in stationary high confinement (H-mode) regimes without edge localized modes (ELMs). In plasmas maintained by resonant magnetic perturbation (RMP) ELM-suppression and QH-mode the confinement time of fluorine (Z=9) is equivalent to that in ELMing discharges with 40 Hz ELMs. For selected discharges with impurity injection the impurity particle confinement time compared to the energy confinement time is in the range of τ p/τ e ≈ 2 $-$ 3. In QH-mode operation the impurity confinement time is shown to be smaller for intense, coherent magnetic and density fluctuations of the edge harmonicmore » oscillation than weaker fluctuations. Transport coefficients are derived from the time evolution of the impurity density profile and compared to neoclassical and turbulent transport models NEO and TGLF. Neoclassical transport of fluorine is found to be small compared to the experimental values. In the ELMing and RMP ELM-suppressed plasma the impurity transport is affected by the presence of tearing modes. For radii larger than the mode radius the TGLF diffusion coefficient is smaller than the experimental value by a factor of 2-3, while the convective velocity is within error estimates. Low levels of diffusion are observed for radii smaller than the tearing mode radius. In the QH-mode plasma investigated, the TGLF diffusion coefficient higher inside of ρ = 0.4 and lower outside of 0.4 than the experiment, and the TGLF convective velocity is more negative by a factor of approximately 1.7.« less

Aperiodic pressure pulsation under non optimal hydraulic turbine regimes at low swirl number

NASA Astrophysics Data System (ADS)

Skripkin, S. G.; Tsoy, M. A.; Kuibin, P. A.; Shtork, S. I.

2017-09-01

Off-design operating conditions of hydraulic turbines is hindered by pressure fluctuations in the draft tube of the turbine. A precessing helical vortex rope develops, which imperils the mechanical structure and limits the operation flexibility of hydropower station. Understanding of the underlying instabilities of precessing vortex rope at low swirl number is incomplete. In this paper flow regimes with different residual swirl is analysed, particular attention is paid to the regime with a small swirl parameter. Study defines upper and low boundaries of regime where aperiodic pressure surge is observed. Flow field at the runner exit is investigated by Laser Doppler Velocimetry and high-speed visualizations, which are complemented draft tube wall pressure measurements.

Changing Waters: Are Climate-Driven Changes in Discharge Regimes Increasing Eutrophication Risk in the Great Lakes Basin?

NASA Astrophysics Data System (ADS)

Van Meter, K. J.; Basu, N. B.

2017-12-01

In recent decades, the Great Lakes Basin (GLB) has experienced increasing precipitation, warming temperatures, and earlier spring thaws. During this same period, the region has been plagued by problems of water quality, with Lake Erie, in particular, experiencing a re-emergence of major eutrophication events, including an increased incidence of Harmful Algal Blooms. Although the prevailing paradigm is that eutrophication of inland waters is directly correlated with total phosphorus (P) inputs, recent decades have seen a decrease in the total P being delivered to the lakes from contributing watersheds. This apparent disconnect between inputs and outputs, i.e. decreasing P inputs but increased eutrophication, has led some to speculate that loading of total P is an insufficient metric of eutrophication risk and that increasing ratios of soluble reactive P (SRP) in relation to the total P (TP) entering inland water bodies may be a more important driver of algal growth. We hypothesize that changes in seasonal discharge patterns may be contributing to changes in the forms of P being delivered to the lakes, potentially due to changes in delivery pathways-for example surface pathways are more dominant in spring snowmelt, while shallow subsurface and tile pathways are more dominant during winter freeze-thaw events. To test this hypothesis, we have utilized data from more than 200 gaging stations across the GLB to explore the influences of climate and changing hydrologic patterns on biogeochemical processing and transport within the GLB. More specifically, we have asked the following questions: 1) How are discharge patterns changing across the GLB? 2) Are SRP:TP ratios increasing in subwatersheds of the GLB, and what are the spatial patterns in these changes? 3) Are climate-related changes in seasonality, e.g. earlier snowmelt, decreasing snowfall, longer growing seasons, linked to increased ratios of bioavailable P? Our results suggest that changes in precipitation as well

Advances in the high bootstrap fraction regime on DIII-D towards the Q  =  5 mission of ITER steady state

NASA Astrophysics Data System (ADS)

Qian, J. P.; Garofalo, A. M.; Gong, X. Z.; Ren, Q. L.; Ding, S. Y.; Solomon, W. M.; Xu, G. S.; Grierson, B. A.; Guo, W. F.; Holcomb, C. T.; McClenaghan, J.; McKee, G. R.; Pan, C. K.; Huang, J.; Staebler, G. M.; Wan, B. N.

2017-05-01

Recent EAST/DIII-D joint experiments on the high poloidal beta {β\\text{P}} regime in DIII-D have extended operation with internal transport barriers (ITBs) and excellent energy confinement (H 98y2 ~ 1.6) to higher plasma current, for lower q 95  ⩽  7.0, and more balanced neutral beam injection (NBI) (torque injection  <  2 Nm), for lower plasma rotation than previous results (Garofalo et al, IAEA 2014, Gong et al 2014 IAEA Int. Conf. on Fusion Energy). Transport analysis and experimental measurements at low toroidal rotation suggest that the E  ×  B shear effect is not key to the ITB formation in these high {β\\text{P}} discharges. Experiments and TGLF modeling show that the Shafranov shift has a key stabilizing effect on turbulence. Extrapolation of the DIII-D results using a 0D model shows that with the improved confinement, the high bootstrap fraction regime could achieve fusion gain Q  =  5 in ITER at {β\\text{N}} ~ 2.9 and q 95 ~ 7. With the optimization of q(0), the required improved confinement is achievable when using 1.5D TGLF-SAT1 for transport simulations. Results reported in this paper suggest that the DIII-D high {β\\text{P}} scenario could be a candidate for ITER steady state operation.

Numerical investigation of trichel pulse of negative corona discharge in N2-O2 mixture

NASA Astrophysics Data System (ADS)

Xia, Qing; Zhang, Yu; Jiang, Zhaorui; Wang, Ronggang; Ouyang, Jiting

2017-12-01

Trichel pulse of negative corona discharge in atmospheric air is investigated numerically using a 2D fluid model. The model consists of a hyperbolic cathode tip and a plane anode, and considers 11 kinds of particles and the most important interactions among them. The spatio-temporal evolution of charged species and the electric field are evaluated during the pulse process. During the pulse rising edge, the positive ions accumulate ahead of the tip forming the temporal cathode sheath, significantly enhancing the local field. In the pulse decay edge, the temporal sheath collapses and the discharge falls back to a low-current mode. In the pulse interval, the discharge does not cease but sustains weakly until the next pulse. The location of the temporal sheath is independent of the averaged value during the Trichel pulse regime and also the same with that in a normal glow regime, which determines a nearly constant pulse rising time at given configurations. However, a smaller tip radius will lead to their decrease. The effect of negative ions on the pulse process is studied by adjusting the attachment rates. It indicates that the negative ions are actually not necessary in the Trichel pulse process, but will influence the pulse waveform significantly.

Electric-discharge-pumped nitrogen ion laser

NASA Technical Reports Server (NTRS)

Laudenslager, J. B.; Pacala, T. J.; Wittig, C.

1976-01-01

The routine operation is described of an N2(+) laser oscillating on the first negative band system of N2(+) which is produced in a preionized transverse discharge device. The discharge design incorporates features which favor the efficient production of the excitation transfer reaction of He2(+) with N2. A capacitive discharge switched by means of a high-current grounded grid thyratron is used to meet the design requirement of a volumetric discharge in high-pressure gas mixtures where the electric discharge need not have an ultrafast rise time (greater than 10 nsec) but should be capable of transferring large quantities of stored electric energy to the gas. A peak power of 180 kW in an 8-nsec laser pulse was obtained with a 0.1% mixture of N2 in helium at a total pressure of 3 atm. The most intense laser oscillations were observed on the (0,1) vibrational transition at 427.8 microns.

Numerical simulation of an oxygen-fed wire-to-cylinder negative corona discharge in the glow regime

NASA Astrophysics Data System (ADS)

Yanallah, K.; Pontiga, F.; Castellanos, A.

2011-02-01

Negative glow corona discharge in flowing oxygen has been numerically simulated for a wire-to-cylinder electrode geometry. The corona discharge is modelled using a fluid approximation. The radial and axial distributions of charged and neutral species are obtained by solving the corresponding continuity equations, which include the relevant plasma-chemical kinetics. Continuity equations are coupled with Poisson's equation and the energy conservation equation, since the reaction rate constants may depend on the electric field and temperature. The experimental values of the current-voltage characteristic are used as input data into the numerical calculations. The role played by different reactions and chemical species is analysed, and the effect of electrical and geometrical parameters on ozone generation is investigated. The reliability of the numerical model is verified by the reasonable agreement between the numerical predictions of ozone concentration and the experimental measurements.

Height Dependency of Aerosol-Cloud Interaction Regimes: Height Dependency of ACI Regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jingyi; Liu, Yangang; Zhang, Minghua

This study investigates the height dependency of aerosol-cloud interaction regimes in terms of the joint dependence of the key cloud microphysical properties (e.g. cloud droplet number concentration, cloud droplet relative dispersion, etc.) on aerosol number concentration (N a) and vertical velocity (w). The three distinct regimes with different microphysical features are the aerosol-limited regime, the updraft-limited regime, and the transitional regime. The results reveal two new phenomena in updraft-limited regime: 1) The “condensational broadening” of cloud droplet size distribution in contrast to the well-known “condensational narrowing” in the aerosol-limited regime; 2) Above the level of maximum supersaturation, some cloud dropletsmore » are deactivated into interstitial aerosols in the updraft-limited regime whereas all droplets remain activated in the aerosol-limited regime. Further analysis shows that the particle equilibrium supersaturation plays important role in understanding these unique features. Also examined is the height of warm rain initiation and its dependence on N a and w. The rain initiation height is found to depend primarily on either N a or w or both in different N a-w regimes, thus suggesting a strong regime dependence of the second aerosol indirect effect.« less

Height Dependency of Aerosol-Cloud Interaction Regimes: Height Dependency of ACI Regime

DOE PAGES

Chen, Jingyi; Liu, Yangang; Zhang, Minghua; ...

2018-01-10

This study investigates the height dependency of aerosol-cloud interaction regimes in terms of the joint dependence of the key cloud microphysical properties (e.g. cloud droplet number concentration, cloud droplet relative dispersion, etc.) on aerosol number concentration (N a) and vertical velocity (w). The three distinct regimes with different microphysical features are the aerosol-limited regime, the updraft-limited regime, and the transitional regime. The results reveal two new phenomena in updraft-limited regime: 1) The “condensational broadening” of cloud droplet size distribution in contrast to the well-known “condensational narrowing” in the aerosol-limited regime; 2) Above the level of maximum supersaturation, some cloud dropletsmore » are deactivated into interstitial aerosols in the updraft-limited regime whereas all droplets remain activated in the aerosol-limited regime. Further analysis shows that the particle equilibrium supersaturation plays important role in understanding these unique features. Also examined is the height of warm rain initiation and its dependence on N a and w. The rain initiation height is found to depend primarily on either N a or w or both in different N a-w regimes, thus suggesting a strong regime dependence of the second aerosol indirect effect.« less

All-regime combined-cycle plant: Engineering solutions

NASA Astrophysics Data System (ADS)

Berezinets, P. A.; Tumanovskii, G. G.; Tereshina, G. E.; Krylova, I. N.; Markina, V. N.; Migun, E. N.

2016-12-01

The development of distributed power generation systems as a supplement to the centralized unified power grid increases the operational stability and efficiency of the entire power generation industry and improves the power supply to consumers. An all-regime cogeneration combined-cycle plant with a power of 20-25 mW (PGU-20/25T) and an electrical efficiency above 50% has been developed at the All-Russia Thermal Engineering Institute (ATEI) as a distributed power generation object. The PGU-20/25T two-circuit cogeneration plant provides a wide electrical and thermal power adjustment range and the absence of the mutual effect of electrical and thermal power output regimes at controlled frequency and power in a unified or isolated grid. The PGU-20/25T combined-cycle plant incorporates a gas-turbine unit (GTU) with a power of 16 MW, a heat recovery boiler (HRB) with two burners (before the boiler and the last heating stage), and a cogeneration steam turbine with a power of 6/9 MW. The PGU-20/25T plant has a maximum electrical power of 22 MW and an efficiency of 50.8% in the heat recovery regime and a maximum thermal power output of 16.3 MW (14 Gcal/h) in the cogeneration regime. The use of burners can increase the electrical power to 25 MW in the steam condensation regime at an efficiency of 49% and the maximum thermal power output to 29.5 MW (25.4 Gcal/h). When the steam turbine is shut down, the thermal power output can grow to 32.6 MW (28 Gcal/h). The innovative equipment, which was specially developed for PGU-20/25T, improves the reliability of this plant and simplifies its operation. Among this equipment are microflame burners in the heat recovery boiler, a vacuum system based on liquid-ring pumps, and a vacuum deaerator. To enable the application of PGU-20/25T in water-stressed regions, an air condenser preventing the heat-transfer tubes from the risk of covering with ice during operation in frost air has been developed. The vacuum system eliminates the need for

The Impact of Harness Impedance on Hall Thruster Discharge Oscillations

NASA Technical Reports Server (NTRS)

Pinero, Luis R.

2017-01-01

Hall thrusters exhibit characteristic discharge voltage and current oscillations during steady-state operation. The lower frequency breathing-mode current oscillations are inherent to each thruster and could impact thruster operation and power processing unit (PPU) design. The design of the discharge output filter, in particular, the output capacitor is important because it supplies the high peak current oscillations that the thruster demands. However, space-rated, high-voltage capacitors are not readily available and can have significant mass and volume. So, it is important for a PPU designer to know what is the minimum amount of capacitance required to operate a thruster. Through Simulation Program with Integrated Circuit Emphasis modeling and electrical measurements on the Hall Effect Rocket with Magnetic Shielding thruster, it was shown that the harness impedance between the power supply and the thruster is the main contributor towards generating voltage ripple at the thruster. Also, increasing the size of the discharge filter capacitor, as previously implemented during thruster tests, does not reduce the voltage oscillations. The electrical characteristics of the electrical harness between the discharge supply and the thruster is crucial to system performance and could have a negative impact on performance, life and operation.

The Impact of Harness Impedance on Hall Thruster Discharge Oscillations

NASA Technical Reports Server (NTRS)

Pinero, Luis R.

2017-01-01

Hall thrusters exhibit characteristic discharge voltage and current oscillations during steady-state operation. The lower frequency breathing-mode current oscillations are inherent to each thruster and could impact thruster operation and PPU design. The design of the discharge output filter, in particular, the output capacitor is important because it supplies the high peak current oscillations that the thruster demands. However, space-rated, high-voltage capacitors are not readily available and can have significant mass and volume. So, it is important for a PPU designer to know what is the minimum amount of capacitance required to operate a thruster. Through SPICE modeling and electrical measurements on the Hall Effect Rocket with Magnetic Shielding (HERMeS) thruster, it was shown that the harness impedance between the power supply and the thruster is the main contributor towards generating voltage ripple at the thruster. Also, increasing the size of the discharge filter capacitor, as previously implemented during thruster tests, does not reduce the voltage oscillations. The electrical characteristics of the electrical harness between the discharge supply and the thruster is crucial to system performance and could have a negative impact on performance, life and operation.

XeCl avalanche discharge laser employing Ar as a diluent

DOEpatents

Sze, R.C.

1979-10-10

A XeCl avalanche discharge exciplex laser which uses a gaseous lasing starting mixture of: 0.2 to 0.4% chlorine donor/2.5% to 10% Xe/97.3% to 89.6% Ar) is provided. The chlorine donor normally comprises HCl but can also comprise CCl/sub 4/ BCl/sub 3/. Use of Ar as a diluent gas reduces operating pressures over other rare gas halide lasers to near atmospheric pressure, increases output lasing power of the XeCl avalanche discharge laser by 30% to exceed KrF avalanche discharge lasing outputs, and is less expensive to operate.

Inertial electrostatic confinement and nuclear fusion in the interelectrode plasma of a nanosecond vacuum discharge. I: Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurilenkov, Yu. K.; Skowronek, M.

2010-12-15

Properties of an aerosol substance with a high power density in the interelectrode space of a nano- second vacuum discharge are studied. The possibilities of emission and/or trapping of fast ions and hard X-rays by ensembles of clusters and microparticles are analyzed. The possibility of simultaneous partial trapping (diffusion) of X-rays and complete trapping of fast ions by a cluster ensemble is demonstrated experimentally. Due to such trapping, the aerosol ensemble transforms into a 'dusty' microreactor that can be used to investigate a certain class of nuclear processes, including collisional DD microfusion. Operating regimes of such a microreactor and theirmore » reproducibility were studied. On the whole, the generation efficiency of hard X-rays and neutrons in the proposed vacuum discharge with a hollow cathode can be higher by two orders of magnitude than that in a system 'high-power laser pulse-cluster cloud.' Multiply repeated nuclear fusion accompanied by pulsating DD neutron emission was reproducibly detected in experiment. Ion acceleration mechanisms in the interelectrode space and the fundamental role of the virtual cathode in observed nuclear fusion processes are discussed.« less

77 FR 6112 - Notice of Final National Pollutant Discharge Elimination System (NPDES) General Permit for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-07

... Elimination System (NPDES) General Permit for Discharges From Concentrated Animal Feeding Operations (CAFOs... permit for discharges from eligible owners/operators of concentrated animal feeding operations (CAFOs... of the final permit, animal feeding operations that are defined as CAFOs or designated as CAFOs by...

Environmental Flows: Evaluating Long-Term Baselines for Hydrological Regime Change in the Southern United States

NASA Astrophysics Data System (ADS)

Deines, A. M.; Morrison, A. M.; Menzie, C.

2016-12-01

The wide variety of ecosystem services associated with running fresh waters are dependent on an assortment of flow conditions including timing and duration of seasonal floods as well as intermittent flows, such as storm peaks. Modern methods of assessing environmental flows consider hydrological regime change by comparing actual or simulated baseline flow conditions against putatively altered regime flows. These calculated flow changes are used as inputs to models of ecosystem responses such as for fish populations, inundated habitat area, or nutrient supplies. However, common and recommended tools and software used to make flow comparisons between putative regimes lack robust mechanisms for evaluating the significance of hydrological regime change in the context of long-term (multiple decades, centuries, or greater) trends, such as climatic conditions, or the facility to determine the existence and causes of regime changes when no obvious discontinuity exists, such as the construction of a dam. As such, environmental flow decisions based on short (recent) baseline records or baseline records assumed to represent stable hydrological conditions may lead to inefficient water use and ecosystem services distribution. Here we examine long-term patterns in discharge, the frequency and severity of regional droughts, and the Atlantic Multidecadal Oscillation to better understand the occurrence and causes of hydrological regime change in rivers in the Southern United States. For each river we ask: 1) Has hydrological regime change occurred? 2) To what degree is observed regime change associated with regional climatic drivers? 3) How might environmental flows suggested by current methods (e.g. the USGS Hydroecological Integrity Assessment or the Indicators of Hydrologic Alteration software) compare with flows derived by additional consideration of long-term drivers of hydrological change? We discuss the different temporal scales through which climate can influence a

Comparison of high-voltage ac and pulsed operation of a surface dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Williamson, James M.; Trump, Darryl D.; Bletzinger, Peter; Ganguly, Biswa N.

2006-10-01

A surface dielectric barrier discharge (DBD) in atmospheric pressure air was excited either by low frequency (0.3-2 kHz) high-voltage ac or by short, high-voltage pulses at repetition rates from 50 to 600 pulses s-1. The short-pulse excited discharge was more diffuse and did not have the pronounced bright multiple cathode spots observed in the ac excited discharge. The discharge voltage, current and average power deposited into the discharge were calculated for both types of excitation. As a measure of plasma-chemical efficiency, the ozone number density was measured by UV absorption as a function of average deposited power. The density of ozone produced by ac excitation did not increase so rapidly as that produced by short-pulse excitation as a function of average power, with a maximum measured density of ~3 × 1015 cm-3 at 25 W. The maximum ozone production achieved by short-pulse excitation was ~8.5 × 1015 cm-3 at 20 W, which was four times greater than that achieved by ac excitation at the same power level.

A Regime Diagram for Subduction

NASA Astrophysics Data System (ADS)

Stegman, D. R.; Farrington, R.; Capitanio, F. A.; Schellart, W. P.

2009-12-01

regimes are generated primarily as a product of two mechanisms. The first mechanism is that of the competition between the weight of the slab and the strength of the plate, which can be understood in terms of the applied bending moment, and this competition results in a particular radius of curvature (for which we provide a simple scaling theory). The second mechanism is the interaction between the slab and the more viscous lower mantle, which produces each regime's distinct slab morphology. Thus, the emergence of five distinct styles of subduction is a direct consequence of the presence of the modest barrier to flow into the lower mantle. Although only 2 of these styles presently operate on Earth, the possibility exists that other modes may have been the predominant mode in the past. Based on these models, we propose that the lithosphere is the primary factor in describing key elements of the plate tectonics system over time, rather than the convecting mantle. We discuss the various factors that may have influenced secular changes in Earth's tectonic behavior, some of which may have interesting consequences for the geochemical evolution of the Earth.

Do dam constructions in a Vietnamese river basin result in change points in hydrologic regime and how reliable are different methods?

NASA Astrophysics Data System (ADS)

Vu, Tinh Thi; Kiesel, Jens; Guse, Bjoern; Fohrer, Nicola

2017-04-01

The damming of rivers causes one of the most considerable impacts of our society on the riverine environment. More than 50% of the world's streams and rivers are currently impounded by dams before reaching the oceans. The construction of dams is of high importance in developing and emerging countries, i.e. for power generation and water storage. In the Vietnamese Vu Gia - Thu Bon Catchment (10,350 km2), about 23 dams were built during the last decades and store approximately 2,156 billion m3 of water. The water impoundment in 10 dams in upstream regions amounts to 17 % of the annual discharge volume. It is expected that impacts from these dams have altered the natural flow regime. However, up to now it is unclear how the flow regime was altered. For this, it needs to be investigated at what point in time these changes became significant and detectable. Many approaches exist to detect changes in stationary or consistency of hydrological records using statistical analysis of time series for the pre- and post-dam period. The objective of this study is to reliably detect and assess hydrologic shifts occurring in the discharge regime of an anthropogenically influenced river basin, mainly affected by the construction of dams. To achieve this, we applied nine available change-point tests to detect change in mean, variance and median on the daily and annual discharge records at two main gauges of the basin. The tests yield conflicting results: The majority of tests found abrupt changes that coincide with the damming-period, while others did not. To interpret how significant the changes in discharge regime are, and to which different properties of the time series each test responded, we calculated Indicators of Hydrologic Alteration (IHAs) for the time period before and after the detected change points. From the results, we can deduce, that the change point tests are influenced in different levels by different indicator groups (magnitude, duration, frequency, etc) and that

Annual bed-elevation regime in the alluvial channel of Squamish River, southwestern British Columbia Canada

USGS Publications Warehouse

Stanford, S.D.; Seidl, M.A.; Ashley, G.M.

2000-01-01

The aim of this study is to examine the annual regime of channel scour and fill by monitoring bed-elevation changes in a reach of Squamish River in southwestern British Columbia, Canada. Sonar surveys of 13 river cross-sections in a sandy gravel-bed single-channel study reach were repeated biweekly over a full hydrologic year (1995/6). The survey results show that bedload movement occurs as waves or pulses forming bedwaves that appear to maintain an overall coherence with movement downstream. These bedwaves propagate downstream by a mode here termed pulse scour and pulse fill, a process distinguished from the conventional mode of scour and fill commonly associated with flood events (here termed local scour and local fill). Bedwave celerity was estimated to be about 15.5 m d-1 corresponding to a bedwave residence time in the study reach of almost one hydrologic year. The total amount of local bed-elevation change ranged between 0.22 m and 2.41 m during the period of study. Analysis of the bed-elevation and flow data reveals that, because of the bedware phenomenon, there is no simple relation between the mean bed-elevation and discharge nor any strong linear correlation among cross-sectional behaviour. The bed-elevation data also suggest that complex changes to the bed within a cross-section are masked when the bed is viewed in one dimension, although no definitive trends in bed behaviour were found in the two-dimensional analysis. Although a weak seasonal effect is evident in this study, the bed-elevation regime is dominated by sediment supply-driven fluctuations in bedload transport occurring at timescales shorter than the seasonal fluctuation in discharge. The study also indicates that bed-elevation monitoring on Squamish River, and others like it, for purposes of detecting and measuring aggradation/degradation must take into account very considerable and normal channel-bed variability operating at timescales from hours to months. Copyright (C) 2000 John Wiley and

Defining the formative discharge for alternate bars in alluvial rivers

NASA Astrophysics Data System (ADS)

Redolfi, M.; Carlin, M.; Tubino, M.; Adami, L.; Zolezzi, G.

2017-12-01

We investigate the properties of alternate bars in long straight reaches of channelized streams subject to an unsteady, irregular flow regime. To this aim we propose a novel integration of a statistical approach with the analytical perturbation model of Tubino (1991) which predicts the evolution of bar properties (namely amplitude and wavelength) as consequence of a flood. The outcomes of our integrated modelling approach are probability distribution of the bar properties, which depend essentially on two ingredients: (i) the statistical properties of the flow regime (duration, frequency and magnitude of the flood events, and (ii) the reach-averaged hydro-geomorphic characteristics of the channel (bed material, channel gradient and width). This allows to define a "bar-forming" discharge value as the flow value which would reproduce the most likely bar properties in a river reach under unsteady flow. Alternate bars are often migrating downstream and growing or declining during flood events. The timescale of bar growth and migration is often comparable with the duration of the floods: consequently, bar properties such as height and wavelength do not respond instantaneously to discharge variations (i.e. quasi-equilibrium response) but may depend on previous flood events. Theoretical results are compared with observations in three Alpine, channelized gravel bed rivers with encouraging outcomes.

Numerical modelling of ozone production in a wire-cylinder corona discharge and comparison with a wire-plate corona discharge

NASA Astrophysics Data System (ADS)

Wang, Pengxiang; Chen, Junhong

2009-02-01

The effect of electrode configuration on ozone production in the direct-current corona discharge of dry and humid air is studied by a numerical model that combines the electron distribution in the corona plasma, plasma chemistry and transport phenomena. Two electrode configurations are considered: wire-cylinder discharge with air flowing along the wire axis and wire-plate discharge with air flowing transverse to the wire. The ozone distributions in both types of discharges are compared. For both electrode configurations, the ozone production rate is higher in the negative corona than in the positive corona and it decreases with an increase in relative humidity. More importantly, the detailed ozone distribution in the neighbourhood of the discharge wire, together with the ozone kinetics, reveals the possible difference in the ozone production from the two discharges. With the same operating conditions and sufficiently short flow residence time, the ozone production rate is nearly the same for both electrode configurations. When the flow residence time is longer than the characteristic time for homogeneous ozone destruction, the net ozone production is higher in the wire-cylinder discharge than in the wire-plate discharge due to relatively less ozone destruction.

Computing discharge using the index velocity method

USGS Publications Warehouse

Levesque, Victor A.; Oberg, Kevin A.

2012-01-01

Application of the index velocity method for computing continuous records of discharge has become increasingly common, especially since the introduction of low-cost acoustic Doppler velocity meters (ADVMs) in 1997. Presently (2011), the index velocity method is being used to compute discharge records for approximately 470 gaging stations operated and maintained by the U.S. Geological Survey. The purpose of this report is to document and describe techniques for computing discharge records using the index velocity method. Computing discharge using the index velocity method differs from the traditional stage-discharge method by separating velocity and area into two ratings—the index velocity rating and the stage-area rating. The outputs from each of these ratings, mean channel velocity (V) and cross-sectional area (A), are then multiplied together to compute a discharge. For the index velocity method, V is a function of such parameters as streamwise velocity, stage, cross-stream velocity, and velocity head, and A is a function of stage and cross-section shape. The index velocity method can be used at locations where stage-discharge methods are used, but it is especially appropriate when more than one specific discharge can be measured for a specific stage. After the ADVM is selected, installed, and configured, the stage-area rating and the index velocity rating must be developed. A standard cross section is identified and surveyed in order to develop the stage-area rating. The standard cross section should be surveyed every year for the first 3 years of operation and thereafter at a lesser frequency, depending on the susceptibility of the cross section to change. Periodic measurements of discharge are used to calibrate and validate the index rating for the range of conditions experienced at the gaging station. Data from discharge measurements, ADVMs, and stage sensors are compiled for index-rating analysis. Index ratings are developed by means of regression

Influence of driving frequency on discharge modes in a dielectric-barrier discharge with multiple current pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Weiman; Tang, Jie; Wang, Yishan

2013-07-15

A one-dimensional self-consistent fluid model was employed to investigate the effect of the driving frequency on the discharge modes in atmospheric-pressure argon discharge with multiple current pulses. The discharge mode was discussed in detail not only at current peaks but also between two adjacent peaks. The simulation results show that different transitions between the Townsend and glow modes during the discharge take place with the driving frequency increased. A complicated transition from the Townsend mode, through glow, Townsend, and glow, and finally back to the Townsend one is found in the discharge with the driving frequency of 8 kHz. Theremore » is a tendency of transition from the Townsend to glow mode for the discharge both at the current peaks and troughs with the increasing frequency. The discharge in the half period can all along operate in the glow mode with the driving frequency high enough. This is resulted from the preservation of more electrons in the gas gap and acquisition of more electron energy from the swiftly varying electric field with the increase in driving frequency. Comparison of the spatial and temporal evolutions of the electron density at different driving frequencies indicates that the increment of the driving frequency allows the plasma chemistry to be enhanced. This electrical characteristic is important for the applications, such as surface treatment and biomedical sterilization.« less

Numerical simulation of operation modes in atmospheric pressure uniform barrier discharge excited by a saw-tooth voltage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Xuechen; Niu Dongying; Yin Zengqian

2012-08-15

The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ionmore » appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.« less

Numerical simulations of dielectric barrier discharges

NASA Astrophysics Data System (ADS)

Martens, Tom

A plasma or gas discharge is a state of matter which can be described as a gas containing ionized atoms and molecules. This ionized gas exhibits a collective behaviour under influence of an electric or a magnetic field, which are responsible for unique properties which make all new kinds of technology possible. The most important motivation behind the research is finding more efficient ways to produce a low-temperature plasma. In order to achieve this different reactor geometries are studied, it is investigated which is the most suitable power source and the influence of small contaminations of the operating gas is assessed. The studied plasmas are mainly operated at atmospheric pressure. Working at this pressure is cheaper and it makes it possible to develop assembly line treatments. Such plasmas are most easily generated in very small geometries, although energetic derailment of the discharge becomes a substantial risk. This is avoided when the electrodes are electrically insulated. In such setup the insulators accumulate charges which compensate the governing electric field, which keeps the energy transfer to the discharge limited. By studying these discharges using computer models, the changes in the plasma chemistry in time and also under the influence of different levels of impurities were characterized in great detail. Moreover, it was also determined how these chemical changes determine the electrical characteristics of the plasma. Finally, the insights in the charging and discharging effects of the insulators were used to make predictions on which type of power source is the most efficient in using the potential energy stored on the insulator surface to generate the plasma. The most important conclusions are that molecular impurities of the order of only one part per million already dominate the ionic particle distributions in the plasma and that a well-designed alteration in the applied voltage profile leads to a plasma generation with a more than three

Evaluating species-specific changes in hydrologic regimes: an iterative approach for salmonids in the Greater Yellowstone Area (USA)

USGS Publications Warehouse

Al-Chokhachy, Robert K.; Sepulveda, Adam; Ray, Andrew M.; Thoma, David P.; Tercek, Michael T.

2017-01-01

Despite the importance of hydrologic regimes to the phenology, demography, and abundance of fishes such as salmonids, there have been surprisingly few syntheses that holistically assess regional, species-specific trends in hydrologic regimes within a framework of climate change. Here, we consider hydrologic regimes within the Greater Yellowstone Area in the Rocky Mountains of western North America to evaluate changes in hydrologic metrics anticipated to affect salmonids, a group of fishes with high regional ecological and socioeconomic value. Our analyses assessed trends across different sites and time periods (1930–, 1950–, and 1970–2015) as means to evaluate spatial and temporal shifts. Consistent patterns emerged from our analyses indicating substantial shifts to (1) earlier peak discharge events; (2) reductions of summer minimum streamflows; (3) declines in the duration of river ice; and (4) decreases in total volume of water. We found accelerated trends in hydrologic change for the 1970–2015 period, with an average peak discharge 7.5 days earlier, 27.5% decline in summer minimum streamflows, and a 15.6% decline in the annual total volume of water (1 October–September 30) across sites. We did observe considerable variability in magnitude of change across sites, suggesting different levels of vulnerability to a changing climate. Our analyses provide an iterative means for assessing climate predictions and an important step in identifying the climate resilience of landscapes.

Remote wind sensing with a CW diode laser lidar beyond the coherence regime.

PubMed

Hu, Qi; Rodrigo, Peter John; Pedersen, Christian

2014-08-15

We experimentally demonstrate for the first time (to our knowledge) a coherent CW lidar system capable of wind speed measurement at a probing distance beyond the coherence regime of the light source. A side-by-side wind measurement was conducted on the field using two lidar systems with identical optical designs but different laser linewidths. While one system was operating within the coherence regime, the other was measuring at least 2.4 times the coherence range. The probing distance of both lidars is 85 m and the radial wind speed correlation was measured to be r2=0.965 between the two lidars at a sampling rate of 2 Hz. Based on our experimental results, we describe a practical guideline for designing a wind lidar operating beyond the coherence regime.

Discharge Characteristics of DC Arc Water Plasma for Environmental Applications

NASA Astrophysics Data System (ADS)

Li, Tianming; Sooseok, Choi; Takayuki, Watanabe

2012-12-01

A water plasma was generated by DC arc discharge with a hafnium embedded rod-type cathode and a nozzle-type anode. The discharge characteristics were examined by changing the operation parameter of the arc current. The dynamic behavior of the arc discharge led to significant fluctuations in the arc voltage and its frequency. Analyses of the high speed image and the arc voltage waveform showed that the arc discharge was in the restrike mode and its frequency varied within several tens of kilohertz according to the operating conditions. The larger thermal plasma volume was generated by the higher flow from the forming steam with a higher restrike frequency in the higher arc current conditions. In addition, the characteristics of the water plasma jet were investigated by means of optical emission spectroscopy to identify the abundant radicals required in an efficient waste treatment process.

Statistical prediction of seasonal discharge in Central Asia for water resources management: development of a generic (pre-)operational modeling tool

NASA Astrophysics Data System (ADS)

Apel, Heiko; Baimaganbetov, Azamat; Kalashnikova, Olga; Gavrilenko, Nadejda; Abdykerimova, Zharkinay; Agalhanova, Marina; Gerlitz, Lars; Unger-Shayesteh, Katy; Vorogushyn, Sergiy; Gafurov, Abror

2017-04-01

The semi-arid regions of Central Asia crucially depend on the water resources supplied by the mountainous areas of the Tien-Shan and Pamirs. During the summer months the snow and glacier melt dominated river discharge originating in the mountains provides the main water resource available for agricultural production, but also for storage in reservoirs for energy generation during the winter months. Thus a reliable seasonal forecast of the water resources is crucial for a sustainable management and planning of water resources. In fact, seasonal forecasts are mandatory tasks of all national hydro-meteorological services in the region. In order to support the operational seasonal forecast procedures of hydromet services, this study aims at the development of a generic tool for deriving statistical forecast models of seasonal river discharge. The generic model is kept as simple as possible in order to be driven by available hydrological and meteorological data, and be applicable for all catchments with their often limited data availability in the region. As snowmelt dominates summer runoff, the main meteorological predictors for the forecast models are monthly values of winter precipitation and temperature as recorded by climatological stations in the catchments. These data sets are accompanied by snow cover predictors derived from the operational ModSnow tool, which provides cloud free snow cover data for the selected catchments based on MODIS satellite images. In addition to the meteorological data antecedent streamflow is used as a predictor variable. This basic predictor set was further extended by multi-monthly means of the individual predictors, as well as composites of the predictors. Forecast models are derived based on these predictors as linear combinations of up to 3 or 4 predictors. A user selectable number of best models according to pre-defined performance criteria is extracted automatically by the developed model fitting algorithm, which includes a test

Does arousal interfere with operant conditioning of spike-wave discharges in genetic epileptic rats?

PubMed

Osterhagen, Lasse; Breteler, Marinus; van Luijtelaar, Gilles

2010-06-01

One of the ways in which brain computer interfaces can be used is neurofeedback (NF). Subjects use their brain activation to control an external device, and with this technique it is also possible to learn to control aspects of the brain activity by operant conditioning. Beneficial effects of NF training on seizure occurrence have been described in epileptic patients. Little research has been done about differentiating NF effectiveness by type of epilepsy, particularly, whether idiopathic generalized seizures are susceptible to NF. In this experiment, seizures that manifest themselves as spike-wave discharges (SWDs) in the EEG were reinforced during 10 sessions in 6 rats of the WAG/Rij strain, an animal model for absence epilepsy. EEG's were recorded before and after the training sessions. Reinforcing SWDs let to decreased SWD occurrences during training; however, the changes during training were not persistent in the post-training sessions. Because behavioural states are known to have an influence on the occurrence of SWDs, it is proposed that the reinforcement situation increased arousal which resulted in fewer SWDs. Additional tests supported this hypothesis. The outcomes have implications for the possibility to train SWDs with operant learning techniques. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Broad-beam high-current dc ion source based on a two-stage glow discharge plasma.

PubMed

Vizir, A V; Oks, E M; Yushkov, G Yu

2010-02-01

We have designed, made, and demonstrated a broad-beam, dc, ion source based on a two-stage, hollow-cathode, and glow discharges plasma. The first-stage discharge (auxiliary discharge) produces electrons that are injected into the cathode cavity of a second-stage discharge (main discharge). The electron injection causes a decrease in the required operating pressure of the main discharge down to 0.05 mTorr and a decrease in required operating voltage down to about 50 V. The decrease in operating voltage of the main discharge leads to a decrease in the fraction of impurity ions in the ion beam extracted from the main gas discharge plasma to less than 0.2%. Another feature of the source is a single-grid accelerating system in which the ion accelerating voltage is applied between the plasma itself and the grid electrode. The source has produced steady-state Ar, O, and N ion beams of about 14 cm diameter and current of more than 2 A at an accelerating voltage of up to 2 kV.

Fundamental experiment of ion thruster using ECR discharge

NASA Astrophysics Data System (ADS)

Yasui, Toshiaki; Kitayama, Jiro; Tahara, Hirokazu; Onoe, Ken-Ichi; Yoshikawa, Takao

A microwave ion thruster has the potential to overcome a lifetime problem of electric propulsion by eliminating electrodes. Two types of microwave ion thruster have been investigated to examine the operational characteristics. The one is the thruster using cavity-resonance microwave discharge, and the other is the thruster using Electron Cyclotron Resonance (ECR) discharge. Cavity-resonance microwave discharge produced plasmas by strong electric field in the resonant cavity and sustained plasmas at argon mass flow rates above 10 sccm. However, ECR discharge was capable of sustaining plasmas at lower mass flow rate, because ECR discharge efficiently produced plasmas by resonance absorption. From these generated microwave plasmas, ions were electrostatically extracted by two multiaperture grids. In ECR discharge, the maximum ion beam current of 75 mA and the highest mass utilization efficiency of 18.7% were achieved at a total extraction voltage of 950 V.

High Power ECR Ion Thruster Discharge Characterization

NASA Technical Reports Server (NTRS)

Foster, John E.; Kamhawi, Hani; Haag, Thomas; Carpenter, Christian; Williams, George W.

2006-01-01

Electron cyclotron resonance (ECR) based ion thrusters with carbon based ion optics can potentially satisfy lifetime requirements for long duration missions (approximately 10 years) because grid erosion and cathode insert depletion issues are virtually eliminated. Though the ECR plasma discharge has been found to typically operate at slightly higher discharge losses than conventional DC ion thrusters (for high total thruster power applications), the discharge power fraction is small (less than 1 percent at 25 kW). In this regard, the benefits of increased life, low discharge plasma potentials, and reduced complexity are welcome tradeoffs for the associated discharge efficiency decrease. Presented here are results from discharge characterization of a large area ECR plasma source for gridded ion thruster applications. These measurements included load matching efficacy, bulk plasma properties via Langmuir probe, and plasma uniformity as measured using current probes distributed at the exit plane. A high degree of plasma uniformity was observed (flatness greater than 0.9). Additionally, charge state composition was qualitatively evaluated using emission spectroscopy. Plasma induced emission was dominated by xenon ion lines. No doubly charged xenon ions were detected.

High performance discharges in the Lithium Tokamak eXperiment with liquid lithium walls

DOE PAGES

Schmitt, J. C.; Bell, R. E.; Boyle, D. P.; ...

2015-05-15

The first-ever successful operation of a tokamak with a large area (40% of the total plasma surface area) liquid lithium wall has been achieved in the Lithium Tokamak eXperiment (LTX). These results were obtained with a new, electron beam-based lithium evaporation system, which can deposit a lithium coating on the limiting wall of LTX in a five-minute period. Preliminary analyses of diamagnetic and other data for discharges operated with a liquid lithium wall indicate that confinement times increased by 10 x compared to discharges with helium-dispersed solid lithium coatings. Ohmic energy confinement times with fresh lithium walls, solid and liquid,more » exceed several relevant empirical scaling expressions. Spectroscopic analysis of the discharges indicates that oxygen levels in the discharges limited on liquid lithium walls were significantly reduced compared to discharges limited on solid lithium walls. Finally, Tokamak operations with a full liquid lithium wall (85% of the total plasma surface area) have recently started.« less

Advanced high frequency partial discharge measuring system

NASA Technical Reports Server (NTRS)

Karady, George G.

1994-01-01

This report explains the Advanced Partial Discharge Measuring System in ASU's High Voltage Laboratory and presents some of the results obtained using the setup. While in operation an insulation is subjected to wide ranging temperature and voltage stresses. Hence, it is necessary to study the effect of temperature on the behavior of partial discharges in an insulation. The setup described in this report can be used to test samples at temperatures ranging from -50 C to 200 C. The aim of conducting the tests described herein is to be able to predict the behavior of an insulation under different operating conditions in addition to being able to predict the possibility of failure.

Uncertainties in discharge projections in consequence of climate change

NASA Astrophysics Data System (ADS)

Liebert, J.; Düthmann, D.; Berg, P.; Feldmann, H.; Ihringer, J.; Kunstmann, H.; Merz, B.; Ott, I.; Schädler, G.; Wagner, S.

2012-04-01

The fourth assessment report of the IPCC summarizes possible effects of the global climate change. For Europe an increasing variability of temperature and precipitation is expected. While the increasing temperature is projected almost uniformly for Europe, for precipitation the models indicate partly heterogeneous tendencies. In order to maintain current safety-standards in the infrastructure of our various water management systems, the possible future floods discharges are very often a central question. In the planning and operation of water infrastructure systems uncertainties considerations have an important function. In times of climate change the analyses of measured historical gauge data (normally 30 - 80 years) are not sufficient enough, because even significant trends are only valid in the analyzed time period and extrapolations are exceedingly difficult. Therefore combined climate and hydrological modeling for scenario based projections become more and more popular. Regarding that adaptation measures in water infrastructure are in general very time-consuming and cost intensive qualified questions to the variability and uncertainty of model based results are important as well. The CEDIM-Project "Flood hazards in a changing climate" is focusing on both: future changes in flood discharge and assess the uncertainties that are involved in such model based future predictions. In detail the study bases on an ensemble of hydrological model (HM) simulations in 3 representative small to medium sized German river catchments (Ammer, Mulde and Ruhr). The meteorological Input bases on 2 high resolution (7 km) regional climate models (RCM) driven by 2 global climate models (GCM) for the near future (2021 - 2050) following the A1B emission scenario (SRES). Two of the catchments (Ruhr and Mulde) have sub-mountainous and one (Ammer) has alpine character. Besides analyzing the future changes in discharge in the catchments, the describing and potential quantification of the

A Framework to Assess the Cumulative Hydrological Impacts of Dams on flow Regime

NASA Astrophysics Data System (ADS)

Wang, Y.; Wang, D.

2016-12-01

In this study we proposed a framework to assess the cumulative impact of dams on hydrological regime, and the impacts of the Three Gorges Dam on flow regime in Yangtze River were investigated with the framework. We reconstructed the unregulated flow series to compare with the regulated flow series in the same period. Eco-surplus and eco-deficit and the Indicators of Hydrologic Alteration parameters were used to examine the hydrological regime change. Among IHA parameters, Wilcoxon signed-rank test and Principal Components Analysis identified the representative indicators of hydrological alterations. Eco-surplus and eco-deficit showed that the reservoir also changed the seasonal regime of the flows in autumn and winter. Annual extreme flows and October flows changes lead to negative ecological implications downstream from the Three Gorges Dam. Ecological operation for the Three Gorges Dam is necessary to mitigate the negative effects on the river ecosystem in the middle reach of Yangtze River. The framework proposed here could be a robust method to assess the cumulative impacts of reservoir operation.

High intensity discharge device containing oxytrihalides

DOEpatents

Lapatovich, Walter P.; Keeffe, William M.; Liebermann, Richard W.; Maya, Jakob

1987-01-01

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO.sub.2, with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube.

High intensity discharge device containing oxytrihalides

DOEpatents

Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

1987-06-09

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

NASA Astrophysics Data System (ADS)

Guo, Leicheng; Su, Ni; Zhu, Chunyan; He, Qing

2018-05-01

Streamflow and sediment loads undergo remarkable changes in worldwide rivers in response to climatic changes and human interferences. Understanding their variability and the causes is of vital importance regarding river management. With respect to the Changjiang River (CJR), one of the largest river systems on earth, we provide a comprehensive overview of its hydrological regime changes by analyzing long time series of river discharges and sediment loads data at multiple gauge stations in the basin downstream of Three Gorges Dam (TGD). We find profound river discharge reduction during flood peaks and in the wet-to-dry transition period, and slightly increased discharges in the dry season. Sediment loads have reduced progressively since 1980s owing to sediment yield reduction and dams in the upper basin, with notably accelerated reduction since the start of TGD operation in 2003. Channel degradation occurs in downstream river, leading to considerable river stage drop. Lowered river stages have caused a 'draining effect' on lakes by fostering lake outflows following TGD impoundments. The altered river-lake interplay hastens low water occurrence inside the lakes which can worsen the drought given shrinking lake sizes in long-term. Moreover, lake sedimentation has decreased since 2002 with less sediment trapped in and more sediment flushed out of the lakes. These hydrological changes have broad impacts on river flood and drought occurrences, water security, fluvial ecosystem, and delta safety.

The natural sediment regime in rivers: broadening the foundation for ecosystem management

USGS Publications Warehouse

Wohl, Ellen E.; Bledsoe, Brian P.; Jacobson, Robert B.; Poff, N. LeRoy; Rathburn, Sara L.; Walters, David M.; Wilcox, Andrew C.

2015-01-01

Water and sediment inputs are fundamental drivers of river ecosystems, but river management tends to emphasize flow regime at the expense of sediment regime. In an effort to frame a more inclusive paradigm for river management, we discuss sediment inputs, transport, and storage within river systems; interactions among water, sediment, and valley context; and the need to broaden the natural flow regime concept. Explicitly incorporating sediment is challenging, because sediment is supplied, transported, and stored by nonlinear and episodic processes operating at different temporal and spatial scales than water and because sediment regimes have been highly altered by humans. Nevertheless, managing for a desired balance between sediment supply and transport capacity is not only tractable, given current geomorphic process knowledge, but also essential because of the importance of sediment regimes to aquatic and riparian ecosystems, the physical template of which depends on sediment-driven river structure and function.

Discharge prediction in the Upper Senegal River using remote sensing data

NASA Astrophysics Data System (ADS)

Ceccarini, Iacopo; Raso, Luciano; Steele-Dunne, Susan; Hrachowitz, Markus; Nijzink, Remko; Bodian, Ansoumana; Claps, Pierluigi

2017-04-01

The Upper Senegal River, West Africa, is a poorly gauged basin. Nevertheless, discharge predictions are required in this river for the optimal operation of the downstream Manantali reservoir, flood forecasting, development plans for the entire basin and studies for adaptation to climate change. Despite the need for reliable discharge predictions, currently available rainfall-runoff models for this basin provide only poor performances, particularly during extreme regimes, both low-flow and high-flow. In this research we develop a rainfall-runoff model that combines remote-sensing input data and a-priori knowledge on catchment physical characteristics. This semi-distributed model, is based on conceptual numerical descriptions of hydrological processes at the catchment scale. Because of the lack of reliable input data from ground observations, we use the Tropical Rainfall Measuring Mission (TRMM) remote-sensing data for precipitation and the Global Land Evaporation Amsterdam Model (GLEAM) for the terrestrial potential evaporation. The model parameters are selected by a combination of calibration, by match of observed output and considering a large set of hydrological signatures, as well as a-priori knowledge on the catchment. The Generalized Likelihood Uncertainty Estimation (GLUE) method was used to choose the most likely range in which the parameter sets belong. Analysis of different experiments enhances our understanding on the added value of distributed remote-sensing data and a-priori information in rainfall-runoff modelling. Results of this research will be used for decision making at different scales, contributing to a rational use of water resources in this river.

Redefinition of the self-bias voltage in a dielectrically shielded thin sheath RF discharge

NASA Astrophysics Data System (ADS)

Ho, Teck Seng; Charles, Christine; Boswell, Rod

2018-05-01

In a geometrically asymmetric capacitively coupled discharge where the powered electrode is shielded from the plasma by a layer of dielectric material, the self-bias manifests as a nonuniform negative charging in the dielectric rather than on the blocking capacitor. In the thin sheath regime where the ion transit time across the powered sheath is on the order of or less than the Radiofrequency (RF) period, the plasma potential is observed to respond asymmetrically to extraneous impedances in the RF circuit. Consequently, the RF waveform on the plasma-facing surface of the dielectric is unknown, and the behaviour of the powered sheath is not easily predictable. Sheath circuit models become inadequate for describing this class of discharges, and a comprehensive fluid, electrical, and plasma numerical model is employed to accurately quantify this behaviour. The traditional definition of the self-bias voltage as the mean of the RF waveform is shown to be erroneous in this regime. Instead, using the maxima of the RF waveform provides a more rigorous definition given its correlation with the ion dynamics in the powered sheath. This is supported by a RF circuit model derived from the computational fluid dynamics and plasma simulations.

Generation of ozone by pulsed corona discharge over water surface in hybrid gas liquid electrical discharge reactor

NASA Astrophysics Data System (ADS)

Lukes, Petr; Clupek, Martin; Babicky, Vaclav; Janda, Vaclav; Sunka, Pavel

2005-02-01

Ozone formation by a pulse positive corona discharge generated in the gas phase between a planar high voltage electrode made from reticulated vitreous carbon and a water surface with an immersed ground stainless steel plate electrode was investigated under various operating conditions. The effects of gas flow rate (0.5-3 litre min-1), discharge gap spacing (2.5-10 mm), applied input power (2-45 W) and gas composition (oxygen containing argon or nitrogen) on ozone production were determined. Ozone concentration increased with increasing power input and with increasing discharge gap. The production of ozone was significantly affected by the presence of water vapour formed through vaporization of water at the gas-liquid interface by the action of the gas phase discharge. The highest energy efficiency for ozone production was obtained using high voltage pulses of approximately 150 ns duration in Ar/O2 mixtures with the maximum efficiency (energy yield) of 23 g kW h-1 for 40% argon content.

Low pressure arc discharge lamp apparatus with magnetic field generating means

DOEpatents

Grossman, M.W.; George, W.A.; Maya, J.

1987-10-06

A low-pressure arc discharge apparatus having a magnetic field generating means for increasing the output of a discharge lamp is disclosed. The magnetic field generating means, which in one embodiment includes a plurality of permanent magnets, is disposed along the lamp for applying a constant transverse magnetic field over at least a portion of the positive discharge column produced in the arc discharge lamp operating at an ambient temperature greater than about 25 C. 3 figs.

Low pressure arc discharge lamp apparatus with magnetic field generating means

DOEpatents

Grossman, Mark W.; George, William A.; Maya, Jakob

1987-01-01

A low-pressure arc discharge apparatus having a magnetic field generating means for increasing the output of a discharge lamp is disclosed. The magnetic field generating means, which in one embodiment includes a plurality of permanent magnets, is disposed along the lamp for applying a constant transverse magnetic field over at least a portion of the positive discharge column produced in the arc discharge lamp operating at an ambient temperature greater than about 25.degree. C.

Restoring a flow regime through the coordinated operation of a multireservoir system: The case of the Zambezi River basin

NASA Astrophysics Data System (ADS)

Tilmant, A.; Beevers, L.; Muyunda, B.

2010-07-01

Large storage facilities in hydropower-dominated river basins have traditionally been designed and managed to maximize revenues from energy generation. In an attempt to mitigate the externalities downstream due to a reduction in flow fluctuation, minimum flow requirements have been imposed to reservoir operators. However, it is now recognized that a varying flow regime including flow pulses provides the best conditions for many aquatic ecosystems. This paper presents a methodology to derive a trade-off relationship between hydropower generation and ecological preservation in a system with multiple reservoirs and stochastic inflows. Instead of imposing minimum flow requirements, the method brings more flexibility to the allocation process by building upon environmental valuation studies to derive simple demand curves for environmental goods and services, which are then used in a reservoir optimization model together with the demand for energy. The objective here is not to put precise monetary values on environmental flows but to see the marginal changes in release policies should those values be considered. After selecting appropriate risk indicators for hydropower generation and ecological preservation, the trade-off curve provides a concise way of exploring the extent to which one of the objectives must be sacrificed in order to achieve more of the other. The methodology is illustrated with the Zambezi River basin where large man-made reservoirs have disrupted the hydrological regime.

Lithium thionyl chloride high rate discharge

NASA Technical Reports Server (NTRS)

Klinedinst, K. A.

1980-01-01

Improvements in high rate lithium thionyl chloride power technology achieved by varying the electrolyte composition, operating temperature, cathode design, and cathode composition are discussed. Discharge capacities are plotted as a function of current density, cell voltage, and temperature.

Cost efficient environmental survey paths for detecting continuous tracer discharges

NASA Astrophysics Data System (ADS)

Alendal, G.

2017-07-01

Designing monitoring programs for detecting potential tracer discharges from unknown locations is challenging. The high variability of the environment may camouflage the anticipated anisotropic signal from a discharge, and there are a number of discharge scenarios. Monitoring operations may also be costly, constraining the number of measurements taken. By assuming that a discharge is active, and a prior belief on the most likely seep location, a method that uses Bayes' theorem combined with discharge footprint predictions is used to update the probability map. Measurement locations with highest reduction in the overall probability of a discharge to be active can be identified. The relative cost between reallocating and measurements can be taken into account. Three different strategies are suggested to enable cost efficient paths for autonomous vessels.

Experimental and modeling study of the oxidation of acetaldehyde in an atmospheric-pressure pulsed corona discharge

NASA Astrophysics Data System (ADS)

Klett, C.; Touchard, S.; Vega-Gonzalez, A.; Redolfi, M.; Bonnin, X.; Hassouni, K.; Duten, X.

2012-08-01

This paper reports the results obtained for the degradation of acetaldehyde by an atmospheric plasma corona discharge working in a pulsed regime. It was shown that a few hundred ppm of acetaldehyde diluted in a pure N2 gas flow can be removed up to 80% by a discharge fed with an electric power lower than 1 W. Under the same conditions, adding up to 5% of O2 allowed the removal of up to 95% of the initial acetaldehyde. The main identified end products were CO2, CO and methanol. A quasi-homogeneous zero-dimensional chemical model was developed to investigate the respective efficiency of the discharge and post-discharge periods in the global removal of the pollutant. The identified main pathways of acetaldehyde degradation were quenching of N2 metastable states during plasma pulses and oxidation by O and OH radicals during the post-discharge. This latter contribution increased with input power because of ozone accumulation in the gas mixture acting as an additional oxygen reservoir.

Efficient 'Foton' electric-discharge KrCl laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panchenko, Aleksei N; Tarasenko, Viktor F

The design of the 'Foton' electric-discharge laser, optimised for operation on the basis of KrCl* molecules, and its energy parameters were investigated. At {lambda} = 222 nm the radiation energy was up to 250 mJ per pulse. The specific output radiation energy was 2.5 J litre{sup -1} and the laser efficiency was in excess of 0.8%. The possibility of further improvement of the characteristics of electric-discharge KrCl lasers are discussed. (lasers)

Optical and electrical characteristics of hollow-needle to plate atmospheric-pressure discharge in nitrogen

NASA Astrophysics Data System (ADS)

Simek, Milan; Schmidt, Jiri; Pekarek, Stanislav; Khun, Josef

2006-10-01

We have studied basic optical and electrical characteristics of the DC hollow needle to plate electrical discharge enhanced by the gas flow through the needle. Substantial advantage of this arrangement is that all gas supplied to the discharge passes through the discharge zone and therefore it is affected by plasma chemical processes. Depending on the energy dissipated between electrodes, we previously observed two basic discharge regimes: a) DC corona and b) DC corona superimposed with pulsed filamentary streamers [1]. In this work, we have analyzed radiation induced by filamentary streamers. In addition to nitrogen emissions driven by electron impact processes we have detected emission induced by specific energy transfer processes [2]. We have also determined mean repetition frequency of filamentary streamers (0.1-15 kHz) for the needle-to-plane gap and for the nitrogen flow through the needle ranging between 2-6 mm and 1-10 slm, respectively. [1] M. Simek and S.Pekarek, GEC 2005, Bul. Am. Phys. Soc. 50, 29, (2005) ; [2] M. Simek at al, Pure Appl. Chem. 78, 1213, (2006).

DC discharges in atmospheric air for bio-decontamination - spectroscopic methods for mechanism identification

NASA Astrophysics Data System (ADS)

Machala, Z.; Jedlovský, I.; Chládeková, L.; Pongrác, B.; Giertl, D.; Janda, M.; Ikurová, L. Å.; Polčic, P.

2009-08-01

Three types of DC electrical discharges in atmospheric air (streamer corona, transient spark and glow discharge) were tested for bio-decontamination of bacteria and yeasts in water solution, and spores on surfaces. Static vs. flowing treatment of contaminated water were compared, in the latter the flowing water either covered the grounded electrode or passed through the high voltage needle electrode. The bacteria were killed most efficiently in the flowing regime by transient spark. Streamer corona was efficient when the treated medium flew through the active corona region. The spores on plastic foil and paper surfaces were successfully inactivated by negative corona. The microbes were handled and their population evaluated by standard microbiology cultivation procedures. The emission spectroscopy of the discharges and TBARS (thiobarbituric acid reactive substances) absorption spectrometric detection of the products of lipid peroxidation of bacterial cell membranes indicated a major role of radicals and reactive oxygen species among the bio-decontamination mechanisms.

NPDES (National Pollution Discharge & Elimination System) Minor Dischargers

EPA Pesticide Factsheets

As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. The NPDES permit program regulates direct discharges from municipal and industrial wastewater treatment facilities that discharge directly into surface waters. The NPDES permit program is part of the Permit Compliance System (PCS) which issues, records, tracks, and regulates point source discharge facilities. Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES permit. Facilities in PCS are identified as either major or minor. Within the major/minor classification, facilities are grouped into municipals or non-municipals. In many cases, non-municipals are industrial facilities. This data layer contains Minor dischargers. Major municipal dischargers include all facilities with design flows of greater than one million gallons per day; minor dischargers are less that one million gallons per day. Essentially, a minor discharger does not meet the discharge criteria for a major. Since its introduction in 1972, the NPDES permit program is responsible for significant improvements to our Nation's water quality.

Simulated Beam Extraction Performance Characterization of a 50-cm Ion Thruster Discharge

NASA Technical Reports Server (NTRS)

Foster, John E.; Hubble, Aimee; Nowak-Gucker, Sarah; Davis, Chris; Peterson, Peter; Viges, Eric; Chen, Dave

2013-01-01

A 50 cm ion thruster is being developed to operate at >65 percent total efficiency at 11 kW, 2700 s Isp and over 25 kW, 4500 s Isp at a total efficiency of >75 percent. The engine is being developed to address the need for a multimode system that can provide a range of thrust-to- power to service national and commercial near-earth onboard propulsion needs such as station-keeping and orbit transfer. Operating characteristics of the 50 cm ion thruster were measured under simulated beam extraction. The discharge current distribution at the various magnet rings was measured over a range of operating conditions. The relationship between the anode current distribution and the resulting plasma uniformity and ion flux measured at the thruster exit plane is discussed. The thermal envelope will also be investigated through the monitoring of magnet temperatures over the range of discharge powers investigated. Discharge losses as a function of propellant utilization was also characterized at multiple simulated beam currents. Bulk plasma conditions such as electron temperature and electron density near engine centerline was measured over a range of operating conditions using an internal Langmuir probe. Sensitivity of discharge performance to chamber length is also discussed. This data acquired from this discharge study will be used in the refinement of a throttle table in anticipation for eventual beam extraction testing.

Ion flow experiments in a multipole discharge chamber

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Robinson, R. S.; Frisa, L. E.

1982-01-01

It has been customary to assume that ions flow nearly equally in all directions from the ion production region within an electron-bombardment discharge chamber. Ion flow measurements in a multipole discharge chamber have shown that this assumption is not true. In general, the electron current through a magnetic field can alter the electron density, and hence the ion density, in such a way that ions tend to be directed away from the region bounded by the magnetic field. When this mechanism is understood, it becomes evident that many past discharge chamber designs have operated with a preferentially directed flow of ions.

Observation of an abrupt electron heating mode transition in capacitive single radio frequency discharges

NASA Astrophysics Data System (ADS)

Wilczek, Sebastian; Trieschmann, Jan; Schulze, Julian; Brinkmann, Ralf Peter; Mussenbrock, Thomas; Derzsi, Aranka; Korolov, Ihor; Donkó, Zoltan

2013-09-01

The electron heating in capacitive discharges at very low pressures (~1 Pa) is dominated by stochastic heating. In this regime electrons are accelerated by the oscillating sheaths, traverse through the plasma bulk and interact with the opposite sheath. By varying the driving frequency or the gap size of the discharge, energetic electrons reach the sheath edge at different temporal phases, i.e., the collapsing or expanding phase, or the moment of minimum sheath width. This work reports numerical experiments based on Particle-In-Cell simulations which show that at certain frequencies the discharge switches abruptly from a low density mode in a high density mode. The inverse transition is also abrupt, but shows a significant hysteresis. This behavior is explained by the complex interaction of the bulk and the sheath. This work is supported by the German Research Foundation in the frame of TRR 87.

Observation of dynamic interactions between fundamental and second-harmonic modes in a high-power sub-terahertz gyrotron operating in regimes of soft and hard self-excitation.

PubMed

Saito, Teruo; Tatematsu, Yoshinori; Yamaguchi, Yuusuke; Ikeuchi, Shinji; Ogasawara, Shinya; Yamada, Naoki; Ikeda, Ryosuke; Ogawa, Isamu; Idehara, Toshitaka

2012-10-12

Dynamic mode interaction between fundamental and second-harmonic modes has been observed in high-power sub-terahertz gyrotrons [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009); T. Saito et al. Phys. Plasmas 19, 063106 (2012)]. Interaction takes place between a parasitic fundamental or first-harmonic (FH) mode and an operating second-harmonic (SH) mode, as well as among SH modes. In particular, nonlinear excitation of the parasitic FH mode in the hard self-excitation regime with assistance of a SH mode in the soft self-excitation regime was clearly observed. Moreover, both cases of stable two-mode oscillation and oscillation of the FH mode only were observed. These observations and theoretical analyses of the dynamic behavior of the mode interaction verify the nonlinear hard self-excitation of the FH mode.

Measurement of laser absorptivity for operating parameters characteristic of laser drilling regime

NASA Astrophysics Data System (ADS)

Schneider, M.; Berthe, L.; Fabbro, R.; Muller, M.

2008-08-01

Laser drilling in the percussion regime is commonly used in the aircraft industry to drill sub-millimetre holes in metallic targets. Characteristic laser intensities in the range of 10 MW cm-2 are typically employed for drilling metallic targets. With these intensities the temperature of the irradiated matter is above the vaporization temperature and the drilling process is led by hydrodynamic effects. Although the main physical processes involved are identified, this process is not correctly understood or completely controlled. A major characteristic coefficient of laser-matter interaction for this regime, which is the absorptivity of the laser on the irradiated surface, is still unknown, because of the perturbing effects due to laser beam geometrical trapping inside the drilled hole. So, by using time resolved experiments, this study deals with the direct measurement of the variation of the intrinsic absorption of aluminium, nickel and steel materials, as a function of the incident laser intensity up to 20 MW cm-2. We observe that for this incident intensity, the absorptivity can reach up to 80%. This very high and unexpected value is discussed by considering the microscopic behaviour of the heated matter near the vapour-liquid interface that undergoes possible Rayleigh-Taylor instability or volume absorption.

An experimental system for symmetric capacitive rf discharge studies

NASA Astrophysics Data System (ADS)

Godyak, V. A.; Piejak, R. B.; Alexandrovich, B. M.

1990-09-01

An experimental system has been designed and built to comprehensively study the electrical and plasma characteristics in symmetric capacitively coupled rf discharges at low gas pressures. Descriptions of the system concept, the discharge chamber, the vacuum-gas control system, and the rf matching and electrical measurement system are presented together with some results of electrical measurements carried out in an argon discharge at 13.56 MHz. The system has been specifically designed to facilitate external discharge parameter measurements and probe measurements and to be compatible with a wide variety of other diagnostics. External electrical measurements and probe measurements within the discharge show that it is an ideal vehicle to study low-pressure rf discharge physics. Measurements from this system should be comparable to one-dimensional rf symmetric capacitive discharge theories and may help to verify them. Although only a few results are given here, the system has been operated reliably over a wide range of gas pressures and should give reproducible and accurate results for discharge electrical characteristics and plasma parameters over a wide range of driving frequency and gas components.

Phenomena of oscillations in atmospheric pressure direct current glow discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Fu-cheng; Yan, Wen; Wang, De-zhen

2013-12-15

Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transformmore » spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.« less

Evaluating Spatial Variability in Sediment and Phosphorus Concentration-Discharge Relationships Using Bayesian Inference and Self-Organizing Maps

NASA Astrophysics Data System (ADS)

Underwood, Kristen L.; Rizzo, Donna M.; Schroth, Andrew W.; Dewoolkar, Mandar M.

2017-12-01

Given the variable biogeochemical, physical, and hydrological processes driving fluvial sediment and nutrient export, the water science and management communities need data-driven methods to identify regions prone to production and transport under variable hydrometeorological conditions. We use Bayesian analysis to segment concentration-discharge linear regression models for total suspended solids (TSS) and particulate and dissolved phosphorus (PP, DP) using 22 years of monitoring data from 18 Lake Champlain watersheds. Bayesian inference was leveraged to estimate segmented regression model parameters and identify threshold position. The identified threshold positions demonstrated a considerable range below and above the median discharge—which has been used previously as the default breakpoint in segmented regression models to discern differences between pre and post-threshold export regimes. We then applied a Self-Organizing Map (SOM), which partitioned the watersheds into clusters of TSS, PP, and DP export regimes using watershed characteristics, as well as Bayesian regression intercepts and slopes. A SOM defined two clusters of high-flux basins, one where PP flux was predominantly episodic and hydrologically driven; and another in which the sediment and nutrient sourcing and mobilization were more bimodal, resulting from both hydrologic processes at post-threshold discharges and reactive processes (e.g., nutrient cycling or lateral/vertical exchanges of fine sediment) at prethreshold discharges. A separate DP SOM defined two high-flux clusters exhibiting a bimodal concentration-discharge response, but driven by differing land use. Our novel framework shows promise as a tool with broad management application that provides insights into landscape drivers of riverine solute and sediment export.

Stereotactic radiosurgery - discharge

MedlinePlus

Gamma knife - discharge; Cyberknife - discharge; Stereotactic radiotherapy - discharge; Fractionated stereotactic radiotherapy - discharge; Cyclotrons - discharge; Linear accelerator - discharge; Lineacs - discharge; Proton beam radiosurgery - discharge

Simulated natural hydrologic regime of an intermountain playa conservation site

USGS Publications Warehouse

Sanderson, J.S.; Kotliar, N.B.; Steingraeber, D.A.; Browne, C.

2008-01-01

An intermountain playa wetland preserve in Colorado's San Luis Valley was studied to assess how its current hydrologic function compares to its natural hydrologic regime. Current hydrologic conditions were quantified, and on-site effects of off-site water use were assessed. A water-budget model was developed to simulate an unaltered (i.e., natural) hydrologic regime, and simulated natural conditions were compared to observed conditions. From 1998-2002, observed stream inflows accounted for ??? 80% of total annual water inputs. No ground water discharged to the wetland. Evapotranspiration (ET) accounted for ??? 69% of total annual water loss. Simulated natural conditions differed substantially from current altered conditions with respect to depth, variability, and frequency of flooding. During 1998-2002, observed monthly mean surface-water depth was 65% lower than under simulated natural conditions. Observed monthly variability in water depth range from 129% greater (May) to 100% less (September and October) than simulated. As observed, the wetland dried completely (i.e., was ephemeral) in all years; as simulated, the wetland was ephemeral in two of five years. For the period 1915-2002, the simulated wetland was inundated continuously for as long as 16 years and nine months. The large differences in observed and simulated surface-water dynamics resulted from differences between altered and simulated unaltered stream inflows. The maximum and minimum annual total stream inflows observed from 1998-2005 were 3.1 ?? 106 m3 and 0 m3, respectively, versus 15.5 ?? 106 m3 and 3.2 ?? 106 m3 under simulated natural conditions from 1915-2002. The maximum simulated inflow was 484% greater than observed. These data indicate that the current hydrologic regime of this intermountain playa differs significantly from its natural hydrologic regime, which has important implications for planning and assessing conservation success. ?? 2008, The Society of Wetland Scientists.

Study of a contracted glow in low-frequency plasma-jet discharges operating with argon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minotti, F.; Giuliani, L.; Xaubet, M.

2015-11-15

In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in argon. The discharge has the characteristics of a contracted glow with a current channel of submillimeter diameter and a relatively high voltage cathode layer. In order to interpret the measurements, we consider the separate modeling of each region of the discharge: main channel and cathode layer, which must then be properly matched together. The main current channel was modeled, extending a previous work, as similar to an arc in which joule heating is balanced by lateral heat conduction, without thermal equilibrium betweenmore » electrons and heavy species. The cathode layer model, on the other hand, includes the emission of secondary electrons by ion impact and by additional mechanisms, of which we considered emission due to collision of atoms excited at metastable levels, and field-enhanced thermionic emission (Schottky effect). The comparison of model and experiment indicates that the discharge can be effectively sustained in its contracted form by the secondary electrons emitted by collision of excited argon atoms, whereas thermionic emission is by far insufficient to provide the necessary electrons.« less

An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

NASA Astrophysics Data System (ADS)

Gudmundsson, J. T.; Lundin, D.; Brenning, N.; Raadu, M. A.; Huo, Chunqing; Minea, T. M.

2016-12-01

A new reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with a titanium target. It is then applied to study the temporal behavior of the discharge plasma parameters such as electron density, the neutral and ion composition, the ionization fraction of the sputtered vapor, the oxygen dissociation fraction, and the composition of the discharge current. We study and compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we explore the current increase and find that when the discharge is operated in the metal mode Ar+ and Ti+ -ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+ -ions contribute most significantly to the discharge current and the contribution of O+ -ions, Ti+ -ions, and secondary electron emission is much smaller. Furthermore, we find that recycling of atoms coming from the target, that are subsequently ionized, is required for the current generation in both modes of operation. From the R-IRM results it is found that in the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates. We also show that working gas recycling can lead to very high discharge currents but never to a runaway. It is concluded that the dominating type of recycling determines the discharge current waveform.

Soil thaw effects on river discharge recessions of a subarctic catchment

NASA Astrophysics Data System (ADS)

Ploum, Stefan; Lyon, Steve; Teuling, Ryan; van der Velde, Ype

2017-04-01

limited in spatial extent, these results further support our connectivity hypothesis, which predicts increasing non-linearity of river discharges (higher discharge peaks and lower low flows under the same precipitation regime) as permafrost thaws.

Understanding Hydrological Regime Alterations Caused by dams: the Santiago River case in the Andean Region of the Amazon Basin.

NASA Astrophysics Data System (ADS)

Rosero-Lopez, D.; Flecker, A.; Walter, M. T.

2016-12-01

Water resources in South America have been clearly targeted as key sources for hydropower expansion over the next 30 years. Ecuador, among the most biologically diverse countries in the world, has the highest density of hydropower dams, either operational, under construction, or planned, in the Amazon Basin. Ecuador's ambitious plan to change its energy portfolio is conceived to satisfy the country's demand and to empower the country to be the region's first hydroelectric energy exporter. The Santiago watershed located in the southeast part of the country has 39 facilities either under construction or in operation. The Santiago River and its main tributaries (Zamora and Upano) are expected to be impounded by large dams over the next 10 years. In order to understand the magnitude and potential impacts of regional dam development on hydrological regimes, a 35-year historical data set of stream discharge was analyzed. We examined flow regimes for time series between the construction of each dam, starting with the oldest and largest built in 1982 up until the most recent dam built in 2005. Preliminary results indicate a systematic displacement in flow seasonality following post-dam compared to pre-dam conditions. There are also notable differences in the distributions of peaks and pulses in post-dam flows. The range of changes from these results shows that punctuated and cumulative impacts are related to the size of each new impoundment. These observations and their implications to the livelihoods, biota, and ecosystems services in the Santiago watershed need to be incorporated into a broader cost-benefit analysis of hydropower generation in the western Amazon Basin.

Experimental investigation on a diode-pumped cesium-vapor laser stably operated at continuous-wave and pulse regime.

PubMed

Chen, Fei; Xu, Dongdong; Gao, Fei; Zheng, Changbin; Zhang, Kuo; He, Yang; Wang, Chunrui; Guo, Jin

2015-05-04

Employing a fiber-coupled diode-laser with a center wavelength of 852.25 nm and a line width of 0.17 nm, experimental investigation on diode-end-pumped cesium (Cs) vapor laser stably operated at continuous-wave (CW) and pulse regime is carried out. A 5 mm long cesium vapor cell filled with 60 kPa helium and 20 kPa ethane is used as laser medium. Using an output coupler with reflectivity of 48.79%, 1.26 W 894.57 nm CW laser is obtained at an incident pump power of 4.76 W, corresponding an optical-optical efficiency of 26.8% and a slope-efficiency of 28.8%, respectively. The threshold temperature is 67.5 °C. Stable pulsed cesium laser with a maximum average output power of 2.6 W is obtained at a repetition rate of 76 Hz, and the pulse repetition rate can be extend to 1 kHz with a pulse width of 18 μs.

FIM motor scores for classifying community discharge after inpatient rehabilitation for hip fracture.

PubMed

Wang, Ching-Yi; Graham, James E; Karmarkar, Amol M; Reistetter, Timothy A; Protas, Elizabeth J; Ottenbacher, Kenneth J

2014-06-01

To assess the utility of functional status in classifying patients by discharge setting after inpatient rehabilitation for hip fracture. Retrospective cohort study. A total of 1257 inpatient rehabilitation facilities in the United States. Medicare beneficiaries (N = 117,168) receiving inpatient rehabilitation for hip fracture from 2007 to 2009. Receiver operating characteristic curve analyses to assess the overall discriminatory ability of functional status scores (Functional Independence Measure [FIM] total, FIM cognition, and FIM motor) and to identify the functioning threshold that best differentiates patients by discharge setting. Discharge setting (community versus institutional). Approximately 68% of patients were discharged to the community after inpatient rehabilitation for hip fracture. Receiver operating characteristic curve analyses indicate that discharge FIM motor ratings (area under the curve: 0.84) alone are as effective as a multivariable model (area under the curve: 0.85), including sociodemographic and clinical factors, in discriminating patients discharged to the community from those discharged to an institution. A discharge FIM motor rating of 58 yielded the best balance in sensitivity and specificity for classifying patients by discharge setting. Discharge FIM motor ratings demonstrated good discriminatory ability for classifying discharge setting. An FIM motor rating of 58 may serve as a clinical tool to guide treatment plans and/or as additional information in complex discharge planning decisions for patients with hip fracture. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

An experimental investigation of a hollow cathode discharge

NASA Technical Reports Server (NTRS)

Wilbur, P. J.

1971-01-01

An experimental study of the effects of various modifications to the hollow cathode discharge region of a 20 cm electron bombardment ion thruster is presented. The introduction of electrical insulation between the main and cathode discharge regions is shown to have no significant effect on thruster performance. Adjustment of both the diameter and length of the cathode discharge region from the design condition are examined and the reduced sizes are shown to effect large improvements in propellant utilization when the thruster is operating at about 30% of the design thrust level. Performance improvements are shown to be less significant at higher thrust levels. The feasibility of using a high voltage tickler electrode to initiate the cathode-keeper discharge is considered and results obtained suggest this mode of startup is unsatisfactory.

Arctic circulation regimes

PubMed Central

Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L.

2015-01-01

Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. PMID:26347536

77 FR 44528 - Dry Cargo Residue Discharges in the Great Lakes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-30

...The Coast Guard proposes replacing its existing interim rule with a new rule to regulate the operation of U.S. and foreign vessels carrying bulk dry cargo such as limestone, iron ore, and coal on the U.S. waters of the Great Lakes, and the operation of U.S. bulk dry cargo vessels anywhere on the Great Lakes. Specifically, the Coast Guard proposes new requirements for the discharge of bulk dry cargo residue (DCR) on the U.S. waters of the Great Lakes. The Coast Guard also announces the availability of the tiered Draft Environmental Impact Statement (DEIS) prepared in support of this proposal. The proposed rule would continue to allow non-hazardous and non-toxic discharges of bulk DCR in limited areas of the Great Lakes. However, vessel owners and operators would need to minimize DCR discharges using methods they would be required to document in DCR management plans. The proposed rule would prohibit limestone and clean stone DCR discharges in some waters where they are now permitted. The proposed rule promotes the Coast Guard's strategic goals of maritime mobility and safety and protection of natural resources.

Large discharge-volume, silent discharge spark plug

DOEpatents

Kang, Michael

1995-01-01

A large discharge-volume spark plug for providing self-limiting microdischarges. The apparatus includes a generally spark plug-shaped arrangement of a pair of electrodes, where either of the two coaxial electrodes is substantially shielded by a dielectric barrier from a direct discharge from the other electrode, the unshielded electrode and the dielectric barrier forming an annular volume in which self-terminating microdischarges occur when alternating high voltage is applied to the center electrode. The large area over which the discharges occur, and the large number of possible discharges within the period of an engine cycle, make the present silent discharge plasma spark plug suitable for use as an ignition source for engines. In the situation, where a single discharge is effective in causing ignition of the combustible gases, a conventional single-polarity, single-pulse, spark plug voltage supply may be used.

21 CFR 1250.53 - Discharge of wastes on air conveyances.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Discharge of wastes on air conveyances. 1250.53 Section 1250.53 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... CONVEYANCE SANITATION Equipment and Operation of Land and Air Conveyances § 1250.53 Discharge of wastes on...

21 CFR 1250.53 - Discharge of wastes on air conveyances.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Discharge of wastes on air conveyances. 1250.53 Section 1250.53 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... CONVEYANCE SANITATION Equipment and Operation of Land and Air Conveyances § 1250.53 Discharge of wastes on...

21 CFR 1250.53 - Discharge of wastes on air conveyances.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Discharge of wastes on air conveyances. 1250.53 Section 1250.53 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... CONVEYANCE SANITATION Equipment and Operation of Land and Air Conveyances § 1250.53 Discharge of wastes on...

Turbulent transport regimes and the scrape-off layer heat flux width

NASA Astrophysics Data System (ADS)

Myra, J. R.; D'Ippolito, D. A.; Russell, D. A.

2015-04-01

Understanding the responsible mechanisms and resulting scaling of the scrape-off layer (SOL) heat flux width is important for predicting viable operating regimes in future tokamaks and for seeking possible mitigation schemes. In this paper, we present a qualitative and conceptual framework for understanding various regimes of edge/SOL turbulence and the role of turbulent transport as the mechanism for establishing the SOL heat flux width. Relevant considerations include the type and spectral characteristics of underlying instabilities, the location of the gradient drive relative to the SOL, the nonlinear saturation mechanism, and the parallel heat transport regime. We find a heat flux width scaling with major radius R that is generally positive, consistent with the previous findings [Connor et al., Nucl. Fusion 39, 169 (1999)]. The possible relationship of turbulence mechanisms to the neoclassical orbit width or heuristic drift mechanism in core energy confinement regimes known as low (L) mode and high (H) mode is considered, together with implications for the future experiments.

Discharge rate measurements in a canal using radiotracer methods.

PubMed

Pant, H J; Goswami, Sunil; Biswal, Jayashree; Samantray, J S; Sharma, V K

2016-06-01

Discharge rates of water were measured in a canal using radiotracer methods with an objective to validate the efficacy of Concrete Volute Pumps (CVPs) installed at various pumping stations along the canal. Pulse velocity and dilution methods were applied to measure the discharge rates using Iodine-131 as a radiotracer. The discharge rate measured in one of the sections of the canal using the pulse velocity method was found to be 22.5m(3)/s, whereas the discharge rates measured using the dilution method in four different sections of the canal varied from 20.27 to 20.62m(3)/s with single CVP in operation. The standard error in discharge rate measurements using dilution method ranged from ±1.1 to ±1.8%. The experimentally measured values of the discharge rate were in good agreement with the design value of the discharge rate (20m(3)/s) thus validating the performance of the CVPs used in the canal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Numerical investigation of dielectric barrier discharges

NASA Astrophysics Data System (ADS)

Li, Jing

1997-12-01

A dielectric barrier discharge (DBD) is a transient discharge occurring between two electrodes in coaxial or planar arrangements separated by one or two layers of dielectric material. The charge accumulated on the dielectric barrier generates a field in a direction opposite to the applied field. The discharge is quenched before an arc is formed. It is one of the few non-thermal discharges that operates at atmospheric pressure and has the potential for use in pollution control. In this work, a numerical model of the dielectric barrier discharge is developed, along with the numerical approach. Adaptive grids based on the charge distribution is used. A self-consistent method is used to solve for the electric field and charge densities. The Successive Overrelaxation (SOR) method in a non-uniform grid spacing is used to solve the Poisson's equation in the cylindrically-symmetric coordinate. The Flux Corrected Transport (FCT) method is modified to solve the continuity equations in the non-uniform grid spacing. Parametric studies of dielectric barrier discharges are conducted. General characteristics of dielectric barrier discharges in both anode-directed and cathode-directed streamer are studied. Effects of the dielectric capacitance, the applied field, the resistance in external circuit and the type of gases (O2, air, N2) are investigated. We conclude that the SOR method in an adaptive grid spacing for the solution of the Poisson's equation in the cylindrically-symmetric coordinate is convergent and effective. The dielectric capacitance has little effect on the g-factor of radical production, but it determines the strength of the dielectric barrier discharge. The applied field and the type of gases used have a significant role on the current peak, current pulse duration and radical generation efficiency, discharge strength, and microstreamer radius, whereas the external series resistance has very little effect on the streamer properties. The results are helpful in

Influence of catalyst packing configuration on the discharge characteristics of dielectric barrier discharge reactors: A numerical investigation

NASA Astrophysics Data System (ADS)

Gadkari, Siddharth; Gu, Sai

2018-06-01

A two-dimensional numerical fluid model is developed for studying the influence of packing configurations on dielectric barrier discharge (DBD) characteristics. Discharge current profiles and time averaged electric field strength, electron number density, and electron temperature distributions are compared for the three DBD configurations, plain DBD with no packing, partially packed DBD, and fully packed DBD. The results show that a strong change in discharge behaviour occurs when a DBD is fully packed as compared to partial packing or no packing. While the average electric field strength and electron temperature of a fully packed DBD are higher relative to the other DBD configurations, the average electron density is substantially lower and may impede the DBD reactor performance under certain operating conditions. Possible scenarios of the synergistic effect of the combination of plasma with catalysis are also discussed.

Craniosynostosis repair - discharge

MedlinePlus

... a child's skull to grow together (fuse) too early. ... Craniectomy - child - discharge; Synostectomy - discharge; Strip craniectomy - discharge; Endoscopy-assisted craniectomy - discharge; Sagittal craniectomy - discharge; Frontal-orbital advancement - discharge; FOA - discharge

Dynamical Localization for Discrete Anderson Dirac Operators

NASA Astrophysics Data System (ADS)

Prado, Roberto A.; de Oliveira, César R.; Carvalho, Silas L.

2017-04-01

We establish dynamical localization for random Dirac operators on the d-dimensional lattice, with d\\in { 1, 2, 3} , in the three usual regimes: large disorder, band edge and 1D. These operators are discrete versions of the continuous Dirac operators and consist in the sum of a discrete free Dirac operator with a random potential. The potential is a diagonal matrix formed by different scalar potentials, which are sequences of independent and identically distributed random variables according to an absolutely continuous probability measure with bounded density and of compact support. We prove the exponential decay of fractional moments of the Green function for such models in each of the above regimes, i.e., (j) throughout the spectrum at larger disorder, (jj) for energies near the band edges at arbitrary disorder and (jjj) in dimension one, for all energies in the spectrum and arbitrary disorder. Dynamical localization in theses regimes follows from the fractional moments method. The result in the one-dimensional regime contrast with one that was previously obtained for 1D Dirac model with Bernoulli potential.

Characterizing flow regimes for floodplain forest conservation: An assessment of factors affecting sapling growth and survivorship on three cold desert rivers

USGS Publications Warehouse

Andersen, D.C.

2005-01-01

I analyzed annual height growth and survivorship of Fremont cottonwood (Populus fremontii S. Watson) saplings on three floodplains in Colorado and Utah to assess responses to interannual variation in flow regime and summer precipitation. Mammal exclosures, supplemented with an insecticide treatment at one site, were used to assess flow regime – herbivore interactions. Multiple regression analyses on data collected over 7–11 years indicated that growth of continuously injury-free saplings was positively related to either peak discharge or the maximum 30-day discharge but was not related to interannual decline in the late-summer river stage (ΔWMIN) or precipitation. Growth was fastest where ΔWMIN was smallest and depth to the late-summer water table moderate (≤1.5 m). Survivorship increased with ΔWMIN where the water table was at shallow depths. Herbivory reduced long-term height growth and survivorship by up to 60% and 50%, respectively. The results support the concept that flow history and environmental context determine whether a particular flow will have a net positive or negative influence on growth and survivorship and suggest that the flow regime that best promotes sapling growth and survival along managed rivers features a short spring flood pulse and constant base flow, with no interannual variation in the hydrograph. Because environmental contexts vary, interannual variation may be necessary for best overall stand performance.

Hydropeaking in Nordic rivers - combined analysis from effects of changing climate conditions and energy demands to river regimes

NASA Astrophysics Data System (ADS)

Ashraf, Faisal Bin; Marttila, Hannu; Torabi Haghighi, Ali; Alfredsen, Knut; Riml, Joakim; Kløve, Bjørn

2017-04-01

Increasing national and international demands for more flexible management of the energy resources with more non-storable renewables being used in adapting to the ongoing climate change will influence hydropower operations. Damming and regulation practices of river systems causes homogenization of long term river dynamics but also higher temporal sub-daily flow variations i.e. hydropeaking. In Nordic countries, many major rivers and lakes are regulated for hydropower purposes, which have caused considerable changes in river biotic, hydrologic and morphologic structures. Due to rapidly changing energy markets in the Nordic countries (deregulation of the power market and adding of renewable but intermittent sources of energy like, wind, solar, etc.) sub-daily flow conditions are under change within regulated river systems due to the increased demand on hydropower for providing balancing power. However, holistic analysis from changes in energy markets and its effect on sub-daily river regimes is lacking. This study analyzes the effects of hydropeaking on river regime in Finland, Sweden and Norway using long term high resolution data (15 minutes to hourly time interval) from 72 pristine and 136 regulated rivers with large spatial coverage across Fennoscandia. Since the sub-daily discharge variation is masked through the monthly or daily analyzes, in order to quantify these changes high resolution data is needed. In our study we will document, characterize and classify the impacts of sub-daily flow variation due to regulation and climatic variation on various river systems in Fennoscandia. Further, with increasing social demands for ecosystem services in regulated rivers, it is important to evaluate the new demand and update hydropower operation plan accordingly. We will analyse ecological response relationships along gradients of hydrological alteration for the biological communities, processes of river ecosystems and climate boundaries together with considering the

Estimation of lifespan and economy parameters of steam-turbine power units in thermal power plants using varying regimes

NASA Astrophysics Data System (ADS)

Aminov, R. Z.; Shkret, A. F.; Garievskii, M. V.

2016-08-01

The use of potent power units in thermal and nuclear power plants in order to regulate the loads results in intense wear of power generating equipment and reduction in cost efficiency of their operation. We review the methodology of a quantitative assessment of the lifespan and wear of steam-turbine power units and estimate the effect of various operation regimes upon their efficiency. To assess the power units' equipment wear, we suggest using the concept of a turbine's equivalent lifespan. We give calculation formulae and an example of calculation of the lifespan of a steam-turbine power unit for supercritical parameters of steam for different options of its loading. The equivalent lifespan exceeds the turbine's assigned lifespan only provided daily shutdown of the power unit during the night off-peak time. We obtained the engineering and economical indices of the power unit operation for different loading regulation options in daily and weekly diagrams. We proved the change in the prime cost of electric power depending on the operation regimes and annual daily number of unloading (non-use) of the power unit's installed capacity. According to the calculation results, the prime cost of electric power for the assumed initial data varies from 11.3 cents/(kW h) in the basic regime of power unit operation (with an equivalent operation time of 166700 hours) to 15.5 cents/(kW h) in the regime with night and holiday shutdowns. The reduction of using the installed capacity of power unit at varying regimes from 3.5 to 11.9 hours per day can increase the prime cost of energy from 4.2 to 37.4%. Furthermore, repair and maintenance costs grow by 4.5% and by 3 times, respectively, in comparison with the basic regime. These results indicate the need to create special maneuverable equipment for working in the varying section of the electric load diagram.

Radical prostatectomy - discharge

MedlinePlus

... prostatectomy - discharge; Laparoscopic radical prostatectomy - discharge; LRP - discharge; Robotic-assisted laparoscopic prostatectomy - discharge; RALP - discharge; Pelvic lymphadenectomy - discharge; Prostate cancer - prostatectomy

Resonant-frequency discharge in a multi-cell radio frequency cavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popovic, S; Upadhyay, J; Mammosser, J

2014-11-07

We are reporting experimental results on microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency (SRF) cryomodule (in situ operation). This discharge offers an efficient mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the problemsmore » related to generation and sustaining the multi-cell cavity plasma, which are breakdown and resonant detuning. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal.« less

Venous Thromboembolism-Related Readmission in Emergency General Surgery Patients: A Role for Prophylaxis on Discharge?

PubMed

DeWane, Michael P; Davis, Kimberly A; Schuster, Kevin M; Maung, Adrian A; Becher, Robert D

2018-06-01

Patients undergoing emergency general surgery (EGS) operations experience high rates of venous thromboembolism (VTE). The rates at which thrombus formation occurs after discharge, and whether VTE prophylaxis at discharge might be warranted to prevent readmission, are unknown. This analysis aimed to determine risk factors associated with VTE formation after discharge for EGS operations. An analysis of the American College of Surgeons NSQIP database from 2013 and 2014 of patients undergoing 10 common EGS operations in an emergent fashion. Multivariable logistic regression modeling was used to determine factors that predicted VTE after discharge. A total of 130,036 patients were included. The 30-day VTE rate was 1.30%, with 35% of all VTEs occurring after discharge. Of those who had VTE develop after discharge, 69.4% required readmission. Predictive factors for post-discharge VTE included prolonged length of stay (odds ratio [OR] 5.25; p < 0.001), presence of metastatic cancer (OR 2.23; p < 0.001), urinary tract infection (OR 1.91; p < 0.001), and postoperative sepsis (OR 1.55; p < 0.001). Identified high-risk groups had a rate of readmission with thrombus 6 times greater than that of average-risk EGS patients. More than 30% of VTEs in the EGS population occur after discharge; of these, a vast majority require readmission. Select high-risk EGS subgroups might benefit from prophylactic anticoagulation at discharge. Copyright © 2018 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Transport Equations Resolution By N-BEE Anti-Dissipative Scheme In 2D Model Of Low Pressure Glow Discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraloua, B.; Hennad, A.

The aim of this paper is to determine electric and physical properties by 2D modelling of glow discharge low pressure in continuous regime maintained by term constant source. This electric discharge is confined in reactor plan-parallel geometry. This reactor is filled by Argon monatomic gas. Our continuum model the order two is composed the first three moments the Boltzmann's equations coupled with Poisson's equation by self consistent method. These transport equations are discretized by the finite volumes method. The equations system is resolved by a new technique, it is about the N-BEE explicit scheme using the time splitting method.

On electron heating in a low pressure capacitively coupled oxygen discharge

NASA Astrophysics Data System (ADS)

Gudmundsson, J. T.; Snorrason, D. I.

2017-11-01

We use the one-dimensional object-oriented particle-in-cell Monte Carlo collision code oopd1 to explore the charged particle densities, the electronegativity, the electron energy probability function, and the electron heating mechanism in a single frequency capacitively coupled oxygen discharge, when the applied voltage amplitude is varied. We explore discharges operated at 10 mTorr, where electron heating within the plasma bulk (the electronegative core) dominates, and at 50 mTorr, where sheath heating dominates. At 10 mTorr, the discharge is operated in a combined drift-ambipolar and α-mode, and at 50 mTorr, it is operated in the pure α-mode. At 10 mTorr, the effective electron temperature is high and increases with increased driving voltage amplitude, while at 50 mTorr, the effective electron temperature is much lower, in particular, within the electronegative core, where it is roughly 0.2-0.3 eV, and varies only a little with the voltage amplitude.

The measurement of argon metastable atoms in the barrier discharge plasma

NASA Astrophysics Data System (ADS)

Ghildina, Anna R.; Mikheyev, Pavel Anatolyevich; Chernyshov, Aleksandr Konstantinovich; Lunev, Nikolai Nikolaevich; Azyazov, Valeriy Nikolaevich

2018-04-01

The mandatory condition for efficient operation of an optically-pumped all-rare-gas laser (OPRGL) is the presence of rare gas metastable atoms in the discharge plasma with number density of the order of 1012-1013 cm-3. This requirement mainly depends on the choice of a discharge system. In this study the number density values of argon metastable atoms were obtained in the condition of the dielectric-barrier discharge (DBD) at an atmospheric pressure.

Facilitating emergency hospital evacuation through uniform discharge criteria.

PubMed

Sandra, Keret; Meital, Nahari; Ofer, Merin; Limor, Aharonson-Daniel; Sara, Goldberg; Bruria, Adini

2017-05-01

Though hospitals' operational continuity is crucial, full institutional evacuation may at times be unavoidable. The study's objective was to establish criteria for discharge of patients during complete emergency evacuation and compare scope of patients suitable for discharge pre/post implementation of criteria. Standards for patient discharge during an evacuation were developed based on literature and disaster managers. The standards were reviewed in a two-round Delphi process. All hospitals in Israel were requested to identify inpatients' that could be released home during institutional evacuation. Potential discharges were compared in 2013-2014, before and after formulation of discharge criteria. Consensus exceeding 80% was obtained for four out of five criteria after two Delphi cycles. Average projected discharge rate before and after formulation of criteria was 34.2% and 42.9%, respectively (p<0.001). Variance in potential dischargeable patients was 31-fold less in 2014 than in 2013 (MST=8,452 versus MST=264,366, respectively; p<0.001). Differences were found between small, medium and large hospitals in mean rate of dischargeable patients: 52.1%, 41.5% and 42.2%, respectively (p=0.001). The study's findings enable to forecast the extent of patients that may be released home during full emergency evacuation of a hospital; thereby facilitating preparedness of contingency plans. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterization of direct-current atmospheric-pressure discharges useful for ambient desorption/ionization mass spectrometry.

PubMed

Shelley, Jacob T; Wiley, Joshua S; Chan, George C Y; Schilling, Gregory D; Ray, Steven J; Hieftje, Gary M

2009-05-01

Two relatively new ambient ionization sources, direct analysis in real time (DART) and the flowing atmospheric-pressure afterglow (FAPA), use direct current, atmospheric-pressure discharges to produce reagent ions for the direct ionization of a sample. Although at a first glance these two sources appear similar, a fundamental study reveals otherwise. Specifically, DART was found to operate with a corona-to-glow transition (C-G) discharge whereas the FAPA was found to operate with a glow-to-arc transition (G-A) discharge. The characteristics of both discharges were evaluated on the basis of four factors: reagent-ion production, response to a model analyte (ferrocene), infrared (IR) thermography of the gas used for desorption and ionization, and spatial emission characteristics. The G-A discharge produced a greater abundance and a wider variety of reagent ions than the C-G discharge. In addition, the discharges yielded different adducts and signal strengths for ferrocene. It was also found that the gas exiting the discharge chamber reached a maximum of 235 degrees C and 55 degrees C for the G-A and C-G discharges, respectively. Finally, spatially resolved emission maps of both discharges showed clear differences for N(2)(+) and O(I). These findings demonstrate that the discharges used by FAPA and DART are fundamentally different and should have different optimal applications for ambient desorption/ionization mass spectrometry (ADI-MS).

PONDCALC - A Tool to Estimate Discharge from the Alviso Salt Ponds, California

USGS Publications Warehouse

Shellenbarger, Gregory; Schoellhamer, David H.; Lionberger, Megan A.

2007-01-01

Former commercial salt ponds in Alviso, California, now are operated by the U.S. Fish and Wildlife Service (USFWS) to provide habitat for birds. The USFWS has modified the operation of the ponds to prevent exceedingly high salinity. Ponds that were formerly hydraulically isolated from South San Francisco Bay and adjacent sloughs now are managed as flow-through ponds, and some are allowed to discharge to the Bay and sloughs. This discharge is allowed under a permit issued by the Regional Water Quality Control Board. As a requirement of the permit, the USFWS must estimate the amount of discharge from each discharge pond for the period May through November of each year. To facilitate the accurate estimation of pond discharge, a calculation methodology (hereafter referred to as 'calculator' or PONDCALC) for the discharging Alviso ponds has been developed as a Microsoft Excel file and is presented in this report. The presence of flap gates on one end of the discharge culverts, which allow only outflow from a pond, complicates the hydraulic analysis of flow through the culverts. The equation typically used for culvert flow contains an energy loss coefficient that had to be determined empirically using measured water discharge and head at the discharge structure of one of the ponds. A standard weir-flow equation is included in PONDCALC for discharge calculation in the ponds having weir box structures in addition to culverts. The resulting methodology is applicable only to the five Alviso ponds (A2W, A3W, A7, A14, and A16) that discharge to South San Francisco Bay or adjacent sloughs under the management practices for 2005.

Charge Management in LISA Pathfinder: The Continuous Discharging Experiment

NASA Astrophysics Data System (ADS)

Ewing, Becca Elizabeth

2018-01-01

Test mass charging is a significant source of excess force and force noise in LISA Pathfinder (LPF). The planned design scheme for mitigation of charge induced force noise in LISA is a continuous discharge by UV light illumination. We report on analysis of a charge management experiment on-board LPF conducted during December 2016. We discuss the measurement of test mass charging noise with and without continuous UV illumination, in addition to the dynamic response in the continuous discharge scheme. Results of the continuous discharge system will be discussed for their application to operating LISA with lower test mass charge.

Modeling of plasma chemical processes in the artificial ionized layer in the upper atmosphere by the nanosecond corona discharge

NASA Astrophysics Data System (ADS)

Vikharev, A. L.; Gorbachev, A. M.; Ivanov, O. A.; Kolisko, A. L.; Litvak, A. G.

1993-08-01

The plasma chemical processes in the corona discharge formed in air by a series of high voltage pulses of nanosecond duration are investigated experimentally. The experimental conditions (reduced electric field, duration and repetition frequency of the pulses, gas pressure in the chamber) modeled the regime of creation of the artificial ionized layer (AIL) in the upper atmosphere by a nanosecond microwave discharge. It was found that in a nanosecond microwave discharge predominantly generation of ozone occurs, and that the production of nitrogen dioxide is not large. The energy expenditures for the generation of one O 3 molecule were about 15 eV. On the basis of the experimental results the prognosis of the efficiency of ozone generation in AIL was made.

Life history theory predicts fish assemblage response to hydrologic regimes.

PubMed

Mims, Meryl C; Olden, Julian D

2012-01-01

The hydrologic regime is regarded as the primary driver of freshwater ecosystems, structuring the physical habitat template, providing connectivity, framing biotic interactions, and ultimately selecting for specific life histories of aquatic organisms. In the present study, we tested ecological theory predicting directional relationships between major dimensions of the flow regime and life history composition of fish assemblages in perennial free-flowing rivers throughout the continental United States. Using long-term discharge records and fish trait and survey data for 109 stream locations, we found that 11 out of 18 relationships (61%) tested between the three life history strategies (opportunistic, periodic, and equilibrium) and six hydrologic metrics (two each describing flow variability, predictability, and seasonality) were statistically significant (P < or = 0.05) according to quantile regression. Our results largely support a priori hypotheses of relationships between specific flow indices and relative prevalence of fish life history strategies, with 82% of all significant relationships observed supporting predictions from life history theory. Specifically, we found that (1) opportunistic strategists were positively related to measures of flow variability and negatively related to predictability and seasonality, (2) periodic strategists were positively related to high flow seasonality and negatively related to variability, and (3) the equilibrium strategists were negatively related to flow variability and positively related to predictability. Our study provides important empirical evidence illustrating the value of using life history theory to understand both the patterns and processes by which fish assemblage structure is shaped by adaptation to natural regimes of variability, predictability, and seasonality of critical flow events over broad biogeographic scales.

Analytical expressions for maximum wind turbine average power in a Rayleigh wind regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlin, P.W.

Average or expectation values for annual power of a wind turbine in a Rayleigh wind regime are calculated and plotted as a function of cut-out wind speed. This wind speed is expressed in multiples of the annual average wind speed at the turbine installation site. To provide a common basis for comparison of all real and imagined turbines, the Rayleigh-Betz wind machine is postulated. This machine is an ideal wind machine operating with the ideal Betz power coefficient of 0.593 in a Rayleigh probability wind regime. All other average annual powers are expressed in fractions of that power. Cases consideredmore » include: (1) an ideal machine with finite power and finite cutout speed, (2) real machines operating in variable speed mode at their maximum power coefficient, and (3) real machines operating at constant speed.« less

46 CFR 64.35 - Bottom filling or discharge connection.

Code of Federal Regulations, 2010 CFR

2010-10-01

....35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.35 Bottom filling or discharge... the product, and a manually operated valve that is located— (a) Inside the tank and operated outside...

ANALYSING PERFORMANCE ASSESSMENT IN PUBLIC SERVICES: HOW USEFUL IS THE CONCEPT OF A PERFORMANCE REGIME?

PubMed

Martin, Steve; Nutley, Sandra; Downe, James; Grace, Clive

2016-03-01

Approaches to performance assessment have been described as 'performance regimes', but there has been little analysis of what is meant by this concept and whether it has any real value. We draw on four perspectives on regimes - 'institutions and instruments', 'risk regulation regimes', 'internal logics and effects' and 'analytics of government' - to explore how the concept of a multi-dimensional regime can be applied to performance assessment in public services. We conclude that the concept is valuable. It helps to frame comparative and longitudinal analyses of approaches to performance assessment and draws attention to the ways in which public service performance regimes operate at different levels, how they change over time and what drives their development. Areas for future research include analysis of the impacts of performance regimes and interactions between their visible features (such as inspections, performance indicators and star ratings) and the veiled rationalities which underpin them.

SHEAR-DRIVEN DYNAMO WAVES IN THE FULLY NONLINEAR REGIME

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pongkitiwanichakul, P.; Nigro, G.; Cattaneo, F.

2016-07-01

Large-scale dynamo action is well understood when the magnetic Reynolds number ( Rm ) is small, but becomes problematic in the astrophysically relevant large Rm limit since the fluctuations may control the operation of the dynamo, obscuring the large-scale behavior. Recent works by Tobias and Cattaneo demonstrated numerically the existence of large-scale dynamo action in the form of dynamo waves driven by strongly helical turbulence and shear. Their calculations were carried out in the kinematic regime in which the back-reaction of the Lorentz force on the flow is neglected. Here, we have undertaken a systematic extension of their work tomore » the fully nonlinear regime. Helical turbulence and large-scale shear are produced self-consistently by prescribing body forces that, in the kinematic regime, drive flows that resemble the original velocity used by Tobias and Cattaneo. We have found four different solution types in the nonlinear regime for various ratios of the fluctuating velocity to the shear and Reynolds numbers. Some of the solutions are in the form of propagating waves. Some solutions show large-scale helical magnetic structure. Both waves and structures are permanent only when the kinetic helicity is non-zero on average.« less

Performance of a CW double electric discharge for supersonic CO lasers

NASA Technical Reports Server (NTRS)

Stanton, A. C.; Hanson, R. K.; Mitchner, M.

1980-01-01

The results of an experimental investigation of a CW double discharge in supersonic CO mixtures are reported. Stable discharges in CO/N2 and CO/Ar mixtures, with a maximum energy loading of 0.5 eV/CO molecule, were achieved in a small-scale continuous-flow supersonic channel. Detailed measurements of the discharge characteristics were performed, including electrostatic probe measurements of floating potential and electron number density and spectroscopic measurements of the CO vibrational population distributions. The results of these measurements indicate that the vibrational excitation efficiency of the discharge is approximately 60%, for moderate levels of main discharge current. These experiments, on a small scale, demonstrate that the double-discharge scheme provides adequate vibrational energy loading for efficient CO laser operation under CW supersonic flow conditions.

Brine reuse in ion-exchange softening: salt discharge, hardness leakage, and capacity tradeoffs.

PubMed

Flodman, Hunter R; Dvorak, Bruce I

2012-06-01

Ion-exchange water softening results in the discharge of excess sodium chloride to the aquatic environment during the regeneration cycle. In order to reduce sodium chloride use and subsequent discharge from ion-exchange processes, either brine reclaim operations can be implemented or salt application during regeneration can be reduced. Both result in tradeoffs related to loss of bed volumes treated per cycle and increased hardness leakage. An experimentally validated model was used to compare concurrent water softening operations at various salt application quantities with and without the direct reuse of waste brine for treated tap water of typical midwestern water quality. Both approaches were able to reduce salt use and subsequent discharge. Reducing salt use and discharge by lowering the salt application rate during regeneration consequently increased hardness leakage and decreased treatment capacity. Single or two tank brine recycling systems are capable of reducing salt use and discharge without increasing hardness leakage, although treatment capacity is reduced.

Scalable quantum memory in the ultrastrong coupling regime.

PubMed

Kyaw, T H; Felicetti, S; Romero, G; Solano, E; Kwek, L-C

2015-03-02

Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances.

Scalable quantum memory in the ultrastrong coupling regime

PubMed Central

Kyaw, T. H.; Felicetti, S.; Romero, G.; Solano, E.; Kwek, L.-C.

2015-01-01

Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances. PMID:25727251

Steady and transient regimes in hydropower plants

NASA Astrophysics Data System (ADS)

Gajic, A.

2013-12-01

Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock.

Shoulder replacement - discharge

MedlinePlus

Total shoulder arthroplasty - discharge; Endoprosthetic shoulder replacement - discharge; Partial shoulder replacement - discharge; Partial shoulder arthroplasty - discharge; Replacement - shoulder - discharge; Arthroplasty - shoulder - ...

Operational Characteristics of an Accelerator Driven Fissile Solution System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimpland, Robert Herbert

Operational characteristics represent the set of responses that a nuclear system exhibits during normal operation. Operators rely on this behavior to assess the status of the system and to predict the consequences of off-normal events. These characteristics largely refer to the relationship between power and system operating conditions. The static and dynamic behavior of a chain-reacting system, operating at sufficient power, is primarily governed by reactivity effects. The science of reactor physics has identified and evaluated a number of such effects, including Doppler broadening and shifts in the thermal neutron spectrum. Often these reactivity effects are quantified in the formmore » of feedback coefficients that serve as coupling coefficients relating the neutron population and the physical mechanisms that drive reactivity effects, such as fissile material temperature and density changes. The operational characteristics of such nuclear systems usually manifest themselves when perturbations between system power (neutron population) and system operating conditions arise. Successful operation of such systems requires the establishment of steady equilibrium conditions. However, prior to obtaining the desired equilibrium (steady-state) conditions, an approach from zero-power (startup) must occur. This operational regime may possess certain limiting system conditions that must be maintained to achieve effective startup. Once steady-state is achieved, a key characteristic of this operational regime is the level of stability that the system possesses. Finally, a third operational regime, shutdown, may also possess limiting conditions of operation that must be maintained. This report documents the operational characteristics of a “generic” Accelerator Driven Fissile Solution (ADFS) system during the various operational regimes of startup, steady-state operation, and shutdown. Typical time-dependent behavior for each operational regime will be illustrated, and

Use of flumes in metering discharge at gaging stations

USGS Publications Warehouse

Kilpatrick, F.A.; Schneider, V.R.

1982-01-01

Flumes for metering discharge are usually of two general types--critical-flow flumes and supercritical-flow flumes. In this report the principles underlying the design of each are discussed, the most commonly used flumes of each of the two types are described, and discharge ratings for each are presented. Considerations in choosing and fitting the appropriate flume for a given situation are discussed along with construction techniques and operational experiences.

Beam ion acceleration by ICRH in JET discharges

NASA Astrophysics Data System (ADS)

Budny, R. V.; Gorelenkova, M.; Bertelli, N.; JET Collaboration

2015-11-01

The ion Monte-Carlo orbit integrator NUBEAM, used in TRANSP has been enhanced to include an ``RF-kick'' operator to simulate the interaction of RF fields and fast ions. The RF quasi-linear operator (localized in space) uses a second R-Z orbit integrator. We apply this to analysis of recent JET discharges using ICRH with the ITER-like first wall. An example of results for a high performance Hybrid discharge for which standard TRANSP analysis simulated the DD neutron emission rate below measurements, re-analysis using the RF-kick operator results in increased beam parallel and perpendicular energy densities (~=40% and 15% respectively), and increased beam-thermal neutron emission (~= 35%), making the total rate closer to the measurement. Checks of the numerics, comparisons with measurements, and ITER implications will be presented. Supported in part by the US DoE contract DE-AC02-09CH11466 and by EUROfusion No 633053.

Electrochemical models for the discharge characteristics of the nickel cadmium cell

NASA Technical Reports Server (NTRS)

Spritzer, M. S.

1981-01-01

The potential time characteristics of a preconditioned fully charged cell discharge at constant current was studied. Electrochemical principles applied to the sealed nickel cadmium cell and its behavior and to predict operating characteristics were described. A thermodynamic approach to arrive at several related but different equations and its discharge are reported.

Two discharge modes of a repetitive nanosecond pulsed helium glow discharge under sub-atmospheric pressure in the repetition frequency range of 20 to 600 kHz

NASA Astrophysics Data System (ADS)

Kikuchi, Yusuke; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

2018-05-01

Two discharge modes, α and γ, of a repetitive nanosecond pulsed helium glow discharge at a gas pressure of 10 kPa in the repetition frequency range from 20 to 600 kHz are reported for the first time. The pulsed glow discharge is produced in a pair of parallel plate metal electrodes without insertion of dielectrics. The α mode discharge is volumetrically produced in the electrode gap at a low-repetition frequency, whereas the γ mode discharge is localized at the cathode surface at a high-repetition frequency. At high-repetition frequency, the time interval between voltage pulses is shorter than the lifetime of the afterglow produced by the preceding discharge. Then, the γ mode discharge is maintained by a large number of secondary electrons emitted from the cathode exposed to high-density ions and metastable helium atoms in the afterglow. In the α mode discharge with a low-repetition frequency operation, primary electrons due to gas ionization dominate the ionization process. Thus, a large discharge voltage is needed for the excitation of the α mode discharge. It is established that the bifurcation of α-γ discharge mode, accompanied by a decrease in the discharge voltage, occurs at the high-repetition frequency of ∼120 kHz.

Climate change impact assessment on the hydrological regime of the Kaligandaki Basin, Nepal.

PubMed

Bajracharya, Ajay Ratna; Bajracharya, Sagar Ratna; Shrestha, Arun Bhakta; Maharjan, Sudan Bikash

2018-06-01

The Hindu Kush-Himalayan region is an important global freshwater resource. The hydrological regime of the region is vulnerable to climatic variations, especially precipitation and temperature. In our study, we modelled the impact of climate change on the water balance and hydrological regime of the snow dominated Kaligandaki Basin. The Soil and Water Assessment Tool (SWAT) was used for a future projection of changes in the hydrological regime of the Kaligandaki basin based on Representative Concentration Pathways Scenarios (RCP 4.5 and RCP 8.5) of ensemble downscaled Coupled Model Intercomparison Project's (CMIP5) General Circulation Model (GCM) outputs. It is predicted to be a rise in the average annual temperature of over 4°C, and an increase in the average annual precipitation of over 26% by the end of the 21st century under RCP 8.5 scenario. Modeling results show these will lead to significant changes in the basin's water balance and hydrological regime. In particular, a 50% increase in discharge is expected at the outlet of the basin. Snowmelt contribution will largely be affected by climate change, and it is projected to increase by 90% by 2090.Water availability in the basin is not likely to decrease during the 21st century. The study demonstrates that the important water balance components of snowmelt, evapotranspiration, and water yield at higher elevations in the upper and middle sub-basins of the Kaligandaki Basin will be most affected by the increasing temperatures and precipitation. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Plasma Discharge Process in a Pulsed Diaphragm Discharge System

NASA Astrophysics Data System (ADS)

Duan, Jianjin; Hu, Jue; Zhang, Chao; Wen, Yuanbin; Meng, Yuedong; Zhang, Chengxu

2014-12-01

As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages: (1) Joule heating and heat exchange stage; (2) nucleated site formation; (3) plasma generation (initiation of the breakdown stage); (4) avalanche growth and plasma expansion; (5) plasma contraction; (6) termination of the plasma discharge; and (7) heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

Mach 5 bow shock control by a nanosecond pulse surface dielectric barrier discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishihara, M.; Takashima, K.; Rich, J. W.

2011-06-15

Bow shock perturbations in a Mach 5 air flow, produced by low-temperature, nanosecond pulse, and surface dielectric barrier discharge (DBD), are detected by phase-locked schlieren imaging. A diffuse nanosecond pulse discharge is generated in a DBD plasma actuator on a surface of a cylinder model placed in air flow in a small scale blow-down supersonic wind tunnel. Discharge energy coupled to the actuator is 7.3-7.8 mJ/pulse. Plasma temperature inferred from nitrogen emission spectra is a few tens of degrees higher than flow stagnation temperature, T = 340 {+-} 30 K. Phase-locked Schlieren images are used to detect compression waves generatedmore » by individual nanosecond discharge pulses near the actuator surface. The compression wave propagates upstream toward the baseline bow shock standing in front of the cylinder model. Interaction of the compression wave and the bow shock causes its displacement in the upstream direction, increasing shock stand-off distance by up to 25%. The compression wave speed behind the bow shock and the perturbed bow shock velocity are inferred from the Schlieren images. The effect of compression waves generated by nanosecond discharge pulses on shock stand-off distance is demonstrated in a single-pulse regime (at pulse repetition rates of a few hundred Hz) and in a quasi-continuous mode (using a two-pulse sequence at a pulse repetition rate of 100 kHz). The results demonstrate feasibility of hypersonic flow control by low-temperature, repetitive nanosecond pulse discharges.« less

Molecular systems under shock compression into the dense plasma regime: carbon dioxide and hydrocarbon polymers

NASA Astrophysics Data System (ADS)

Mattsson, Thomas R.; Cochrane, Kyle R.; Root, Seth; Carpenter, John H.

2013-10-01

Density Functional Theory (DFT) has proven remarkably accurate in predicting properties of matter under shock compression into the dense plasma regime. Materials where chemistry plays a role are of interest for many applications, including planetary science and inertial confinement fusion (ICF). As examples of systems where chemical reactions are important, and demonstration of the high fidelity possible for these both structurally and chemically complex systems, we will discuss shock- and re-shock of liquid carbon dioxide (CO2) in the range 100 to 800 GPa and shock compression of hydrocarbon polymers, including GDP (glow discharge polymer) which is used as an ablator in laser ICF experiments. Experimental results from Sandia's Z machine validate the DFT simulations at extreme conditions and the combination of experiment and DFT provide reliable data for evaluating existing and constructing future wide-range equations of state models for molecular compounds. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Electron Information in Single- and Dual-Frequency Capacitive Discharges at Atmospheric Pressure.

PubMed

Park, Sanghoo; Choe, Wonho; Moon, Se Youn; Shi, Jian Jun

2018-05-14

Determining the electron properties of weakly ionized gases, particularly in a high electron-neutral collisional condition, is a nontrivial task; thus, the mechanisms underlying the electron characteristics and electron heating structure in radio-frequency (rf) collisional discharges remain unclear. Here, we report the electrical characteristics and electron information in single-frequency (4.52 MHz and 13.56 MHz) and dual-frequency (a combination of 4.52 MHz and 13.56 MHz) capacitive discharges within the abnormal α-mode regime at atmospheric pressure. A continuum radiation-based electron diagnostic method is employed to estimate the electron density (n e ) and temperature (T e ). Our experimental observations reveal that time-averaged n e (7.7-14 × 10 11  cm -3 ) and T e (1.75-2.5 eV) can be independently controlled in dual-frequency discharge, whereas such control is nontrivial in single-frequency discharge, which shows a linear increase in n e and little to no change in T e with increases in the rf input power. Furthermore, the two-dimensional spatiotemporal evolution of neutral bremsstrahlung and associated electron heating structures is demonstrated. These results reveal that a symmetric structure in electron heating becomes asymmetric (via a local suppression of electron temperature) as two-frequency power is simultaneously introduced.

Deterministic-random separation in nonstationary regime

NASA Astrophysics Data System (ADS)

Abboud, D.; Antoni, J.; Sieg-Zieba, S.; Eltabach, M.

2016-02-01

In rotating machinery vibration analysis, the synchronous average is perhaps the most widely used technique for extracting periodic components. Periodic components are typically related to gear vibrations, misalignments, unbalances, blade rotations, reciprocating forces, etc. Their separation from other random components is essential in vibration-based diagnosis in order to discriminate useful information from masking noise. However, synchronous averaging theoretically requires the machine to operate under stationary regime (i.e. the related vibration signals are cyclostationary) and is otherwise jeopardized by the presence of amplitude and phase modulations. A first object of this paper is to investigate the nature of the nonstationarity induced by the response of a linear time-invariant system subjected to speed varying excitation. For this purpose, the concept of a cyclo-non-stationary signal is introduced, which extends the class of cyclostationary signals to speed-varying regimes. Next, a "generalized synchronous average'' is designed to extract the deterministic part of a cyclo-non-stationary vibration signal-i.e. the analog of the periodic part of a cyclostationary signal. Two estimators of the GSA have been proposed. The first one returns the synchronous average of the signal at predefined discrete operating speeds. A brief statistical study of it is performed, aiming to provide the user with confidence intervals that reflect the "quality" of the estimator according to the SNR and the estimated speed. The second estimator returns a smoothed version of the former by enforcing continuity over the speed axis. It helps to reconstruct the deterministic component by tracking a specific trajectory dictated by the speed profile (assumed to be known a priori).The proposed method is validated first on synthetic signals and then on actual industrial signals. The usefulness of the approach is demonstrated on envelope-based diagnosis of bearings in variable

Dynamic regime marginal structural mean models for estimation of optimal dynamic treatment regimes, Part I: main content.

PubMed

Orellana, Liliana; Rotnitzky, Andrea; Robins, James M

2010-01-01

Dynamic treatment regimes are set rules for sequential decision making based on patient covariate history. Observational studies are well suited for the investigation of the effects of dynamic treatment regimes because of the variability in treatment decisions found in them. This variability exists because different physicians make different decisions in the face of similar patient histories. In this article we describe an approach to estimate the optimal dynamic treatment regime among a set of enforceable regimes. This set is comprised by regimes defined by simple rules based on a subset of past information. The regimes in the set are indexed by a Euclidean vector. The optimal regime is the one that maximizes the expected counterfactual utility over all regimes in the set. We discuss assumptions under which it is possible to identify the optimal regime from observational longitudinal data. Murphy et al. (2001) developed efficient augmented inverse probability weighted estimators of the expected utility of one fixed regime. Our methods are based on an extension of the marginal structural mean model of Robins (1998, 1999) which incorporate the estimation ideas of Murphy et al. (2001). Our models, which we call dynamic regime marginal structural mean models, are specially suitable for estimating the optimal treatment regime in a moderately small class of enforceable regimes of interest. We consider both parametric and semiparametric dynamic regime marginal structural models. We discuss locally efficient, double-robust estimation of the model parameters and of the index of the optimal treatment regime in the set. In a companion paper in this issue of the journal we provide proofs of the main results.

Primary Productivity Regime and Nutrient Removal in the Danube Estuary

NASA Astrophysics Data System (ADS)

Humborg, C.

1997-11-01

The primary productivity regime, as well as the distribution of dissolved inorganic nutrients and particulate organic matter in the Danube estuary, were investigated during several cruises at different discharge regimes of the Danube River. The shallowness of the upper surface layer due to insignificant tidal mixing and strong stratification of the Danube estuary, as well as the high nutrient concentrations, are favourable for elevated primary production. The incident light levels at the bottom of the upper surface layer of the water column (0·5-3·0 m) were generally higher than 20% of the surface irradiance. Elevated chlorophyll (Chl) aconcentrations with maxima at mid salinities were found during each survey. Within the upper mixed layer estimated primary production of 0·2-4·4 g m-2day-1is very high compared with estuaries of other major world rivers. Mixing diagrams of dissolved inorganic nutrients reveal removal of significant quantities of nutrients during estuarine mixing. These observations were consistent with the distribution of particular organic matter, which was negatively correlated to the nutrient distribution during each survey. C:Chl aratios, as well as the elevated estimated production, indicate that biological transformation processes govern the nutrient distribution in this estuary.

33 CFR 157.37 - Discharge of oily mixtures from oil cargoes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... recent year must be retained on board the vessel. (e) Ballast water containing an oily mixture may be... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Discharge of oily mixtures from... CARRYING OIL IN BULK Vessel Operation § 157.37 Discharge of oily mixtures from oil cargoes. (a) A tank...

33 CFR 157.37 - Discharge of oily mixtures from oil cargoes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... recent year must be retained on board the vessel. (e) Ballast water containing an oily mixture may be... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Discharge of oily mixtures from... CARRYING OIL IN BULK Vessel Operation § 157.37 Discharge of oily mixtures from oil cargoes. (a) A tank...

33 CFR 157.37 - Discharge of oily mixtures from oil cargoes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... recent year must be retained on board the vessel. (e) Ballast water containing an oily mixture may be... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Discharge of oily mixtures from... CARRYING OIL IN BULK Vessel Operation § 157.37 Discharge of oily mixtures from oil cargoes. (a) A tank...

33 CFR 157.37 - Discharge of oily mixtures from oil cargoes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... recent year must be retained on board the vessel. (e) Ballast water containing an oily mixture may be... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Discharge of oily mixtures from... CARRYING OIL IN BULK Vessel Operation § 157.37 Discharge of oily mixtures from oil cargoes. (a) A tank...

33 CFR 157.37 - Discharge of oily mixtures from oil cargoes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... recent year must be retained on board the vessel. (e) Ballast water containing an oily mixture may be... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Discharge of oily mixtures from... CARRYING OIL IN BULK Vessel Operation § 157.37 Discharge of oily mixtures from oil cargoes. (a) A tank...

Study of a rare-gas transverse fast discharge

NASA Technical Reports Server (NTRS)

Chubb, D. L.; Michels, C. J.

1979-01-01

An experimental and analytical study of a Blumlein-type transverse fast discharge operating with He and Xe are presented. An electro-optical voltage probe was used to measure the discharge voltage, and the measured voltages were in agreement with the computed voltages. The analytical model was used to predict the dependence of the discharge efficiency for producing metastables and ions on the important plasma and external circuit parameters. In He the ion efficiency is greater than the metastable efficiency, while in Xe it is the opposite; the He ion efficiencies are much larger than in Xe, while Xe metastable efficiencies are much larger than in He. These differences between Xe and He are accounted by the large dissociative recombination rate of Xe compared with He.

Home Antibiotics at Discharge for Pediatric Complicated Appendicitis: Friend or Foe?

PubMed

Anderson, K Tinsley; Bartz-Kurycki, Marisa A; Kawaguchi, Akemi L; Austin, Mary T; Holzmann-Pazgal, Galit; Kao, Lillian S; Lally, Kevin P; Tsao, Kuojen

2018-04-20

The role of home antibiotics (HA) at discharge in children after perforated appendicitis is unclear. This study evaluates the outcomes of complicated appendicitis in patients being discharged with or without HA after initial operation and inpatient treatment. The 2015 and 2016 NSQIP-Pediatric database was queried for patients younger than 18 years of age with complicated appendicitis. Home antibiotics were prescribed or not (no home antibiotics [NHA]). Patients were stratified based on presence or absence of predischarge surgical site infection (SSI) and postoperative day of discharge (≤5 days or >5 days). The primary end point was 30-day postdischarge composite morbidity, including emergency department visit, readmission, postdischarge reoperation, and SSI. Multivariable logistic regression was used to adjust for baseline covariables. Of 6,412 patients with complicated appendicitis, the majority were discharged with HA (HA 56.4%; NHA 43.6%). Patients receiving HA had higher preoperative leukocytosis, longer procedures, higher incidence of sepsis, more predischarge SSIs, and longer length of stay than the NHA cohort (all p < 0.01), suggesting greater severity of illness. In adjusted multivariable models, HA patients without a predischarge SSI had higher postdischarge morbidity (adjusted odds ratio [aOR] 1.22; 95% CI 1.04 to 1.44), as did HA patients discharged ≤5 days post operation (aOR 1.28; 95% CI 1.04 to 1.57) compared with NHA patients. Composite morbidity was similar between NHA and HA patients with predischarge SSIs (aOR 1.06; 95% CI 0.56 to 2.00) or who were discharged >5 days post operation (aOR 1.14; 95% CI 0.89 to 1.46). Although the majority of pediatric patients with complicated appendicitis are discharged with HA, NSQIP-Pediatric data suggest there is no evidence of a significant benefit. There might be a cohort of patients with more severe disease who require continued antibiotics. Copyright © 2018 American College of Surgeons. Published by

State-discharge relations at dams on the Illinois and Des Plaines rivers in Illinois

USGS Publications Warehouse

Mades, Dean M.

1981-01-01

Stage-discharge relations were developed for the Brandon Road Dam on the Des Plainse River and the Dresden Island, Marseilles, Starved Rock, Peoria, and La Grange Dams on the Illinois River. At Brandon Road Dam, streamflow is regulated by the operation of tainter gates and headgates. Tainter gates are operated to regulate streamflow at the Dresden Island, Marseilles, and Starved Rock Dams. Peoria Dam and La Grange Dam comprise timber Chanoine wickets which are lowered to a horizontal position on the streambed when used for streamflow regulation. Both dams have concrete abutments housing butterfly valves that are also used for regulation. A total of 50 discharge measurements ranging from 49.0 to 2,450 cubic meter per second were used to determine discharge coefficients in equations expressing discharge as a function of headwater depth, tailwater depth, and gate opening. A stage-discharge relation for Chanoine wicket dams developed from a U.S. Army Corps of Engineers hydraulic model study in 1937 and 1938 was verified with discharge measurements made downstream from the Peoria and La Grange Dams. (USGS)

Discharge stabilization studies of CO laser gas mixtures in quasi-steady supersonic flow

NASA Technical Reports Server (NTRS)

Srinivasan, G.; Smith, J. A.

1976-01-01

Experiments were conducted to study the applicability of a double discharge stabilization scheme in conditions appropriate for high energy CO lasers in supersonic flows. A Ludwieg tube impulse flow facility and a ballasted capacitor bank provided essentially steady flow and discharge conditions (d.c.) for times longer than ten electrode length-flow transit times. Steady, arc-free, volume discharges were produced in a Mach 3 test cavity using an auxiliary discharge to stabilize the main discharge in N2 and He/CO mixture. A signigicant result is the lack of observed plasma E/N changes in response to auxiliary discharge current changes. Also, where glow discharges were obtained, the energy loading achieved was very much less than the threshold level required for laser operation.

The electrical characteristics of the dielectric barrier discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yehia, Ashraf, E-mail: yehia30161@yahoo.com; Department of Physics, Faculty of Science, Assiut University, Assiut 71516

2016-06-15

The electrical characteristics of the dielectric barrier discharges have been studied in this paper under different operating conditions. The dielectric barrier discharges were formed inside two reactors composed of electrodes in the shape of two parallel plates. The dielectric layers inside these reactors were pasted on the surface of one electrode only in the first reactor and on the surfaces of the two electrodes in the second reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at the normal temperature and pressure, in parallel with applying a sinusoidal ac voltagemore » between the electrodes of the reactor. The amount of the electric charge that flows from the reactors to the external circuit has been studied experimentally versus the ac peak voltage applied to them. An analytical model has been obtained for calculating the electrical characteristics of the dielectric barrier discharges that were formed inside the reactors during a complete cycle of the ac voltage. The results that were calculated by using this model have agreed well with the experimental results under the different operating conditions.« less

Gyrokinetics with Advanced Collision Operators

NASA Astrophysics Data System (ADS)

Belli, E. A.; Candy, J.

2014-10-01

For gyrokinetic studies in the pedestal region, collisions are expected to play a more critical role than in the core and there is concern that more advanced collision operators, as well as numerical methods optimized for the strong collisionality regime, are needed. For this purpose, a new gyrokinetic solver CGYRO has been developed for precise studies of high collisionality regimes. Building on GYRO and NEO, CGYRO uses the NEO pitch angle and energy velocity-space coordinate system to optimize the accuracy of the collision dynamics, particularly for multi-species collisions and including energy diffusion. With implementation of the reduced Hirshman-Sigmar collision operator with full cross-species coupling, CGYRO recovers linear ITG growth rates and the collisional GAM test at moderate collision frequency. Methods to improve the behavior in the collisionless regime, particularly for the trapped/passing particle boundary physics for kinetic electrons, are studied. Extensions to advanced model operators with finite-k⊥ corrections, e.g., the Sugama operator, and the impact of high collisionality on linear gyrokinetic stability in the edge are explored. Work supported by the US DOE under DE-FG02-95ER54309.

Nanoscale discharge electrode for minimizing ozone emission from indoor corona devices.

PubMed

Bo, Zheng; Yu, Kehan; Lu, Ganhua; Mao, Shun; Chen, Junhong; Fan, Fa-Gung

2010-08-15

Ground-level ozone emitted from indoor corona devices poses serious health risks to the human respiratory system and the lung function. Federal regulations call for effective techniques to minimize the indoor ozone production. In this work, stable atmospheric corona discharges from nanomaterials are demonstrated using horizontally suspended carbon nanotubes (CNTs) as the discharge electrode. Compared with the conventional discharges employing micro- or macroscale electrodes, the corona discharge from CNTs could initiate and operate at a much lower voltage due to the small electrode diameter, and is thus energy-efficient. Most importantly, the reported discharge is environmentally friendly since no ozone (below the detection limit of 0.5 ppb) was detected for area current densities up to 0.744 A/m(2) due to the significantly reduced number of electrons and plasma volume generated by CNT discharges. The resulting discharge current density depends on the CNT loading. Contrary to the conventional wisdom, negative CNT discharges should be used to enhance the current density owing to the efficient field emission of electrons from the CNT surface.

Compulsory licensing in Canada and Thailand: comparing regimes to ensure legitimate use of the WTO rules.

PubMed

Lybecker, Kristina M; Fowler, Elisabeth

2009-01-01

This paper examines two recent examples of compulsory licensing legislation: one globally embraced regime and one internationally controversial regime operating under the same WTO rules. In particular, we consider Canadian legislation and the use of compulsory licensing for HIV/AIDS drugs destined for a developing country. This is then contrasted with the conditions under which Thai authorities are pursuing compulsory licenses, the outcomes of their compulsory licenses, as well as the likely impact of the Thai policy. Finally, we construct a rubric to evaluate characteristics of a successful regime. This is used to analyze the Canadian and Thai regimes and frame the expected implications of each national policy. It is hoped that the assessment will guide changes to compulsory licensing design to ensure that legitimate regimes are embraced while illegitimate ones are disallowed.

Cardiac catheterization - discharge

MedlinePlus

Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary artery disease - cardiac catheterization ...

Feasibility of a Clinical Pathway with Early Oral Intake and Discharge for Laparoscopic Gastrectomy.

PubMed

Nakagawa, M; Tomii, C; Inokuchi, M; Otsuki, S; Kojima, K

2017-12-01

Although some studies have reported the safety of early oral intake after gastrectomy, it still remains controversial. This study focused on the feasibility of a clinical pathway with early oral intake and discharge setting for exclusively laparoscopic distal gastrectomy. A clinical pathway was applied to 403 patients until December 2014. In the protocol, patients are allowed to take a sip of water and a soft diet on the first and second days after the operation, respectively, and the discharge day is set as the fifth to seventh day after the operation. Clinicopathological variables were prospectively collected, and risk factors for discharge variances were analyzed. The completion rate of the clinical pathway was 76.9%. There were five re-admissions (1.2%). The overall morbidity rate was 18% ( n = 72), and major complications (Clavien-Dindo IIIa or greater) occurred in 13 patients (3%). Complications were the causes for discharge variances in 68 cases (73%), while the attending surgeons' judgment was the cause in 25 cases (27%). On multivariate analysis, age (odds ratio = 2.23, 95% confidence interval = 1.38-3.60, p = 0.001) and operative time (odds ratio = 2.38, 95% confidence interval = 1.45-3.98, p = 0.001) were independent risk factors for discharge variances. A high completion rate of a clinical pathway with early oral intake and discharge setting for laparoscopic distal gastrectomy was achievable with an acceptably low re-admission rate. Laparoscopic distal gastrectomy is recommended as a first step for a clinical pathway with an early oral intake and discharge protocol.

Neural network based adaptive control for nonlinear dynamic regimes

NASA Astrophysics Data System (ADS)

Shin, Yoonghyun

Adaptive control designs using neural networks (NNs) based on dynamic inversion are investigated for aerospace vehicles which are operated at highly nonlinear dynamic regimes. NNs play a key role as the principal element of adaptation to approximately cancel the effect of inversion error, which subsequently improves robustness to parametric uncertainty and unmodeled dynamics in nonlinear regimes. An adaptive control scheme previously named 'composite model reference adaptive control' is further developed so that it can be applied to multi-input multi-output output feedback dynamic inversion. It can have adaptive elements in both the dynamic compensator (linear controller) part and/or in the conventional adaptive controller part, also utilizing state estimation information for NN adaptation. This methodology has more flexibility and thus hopefully greater potential than conventional adaptive designs for adaptive flight control in highly nonlinear flight regimes. The stability of the control system is proved through Lyapunov theorems, and validated with simulations. The control designs in this thesis also include the use of 'pseudo-control hedging' techniques which are introduced to prevent the NNs from attempting to adapt to various actuation nonlinearities such as actuator position and rate saturations. Control allocation is introduced for the case of redundant control effectors including thrust vectoring nozzles. A thorough comparison study of conventional and NN-based adaptive designs for a system under a limit cycle, wing-rock, is included in this research, and the NN-based adaptive control designs demonstrate their performances for two highly maneuverable aerial vehicles, NASA F-15 ACTIVE and FQM-117B unmanned aerial vehicle (UAV), operated under various nonlinearities and uncertainties.

Sensitivity to spatial and temporal scale and fire regime inputs in deriving fire regime condition class

Treesearch

Linda Tedrow; Wendel J. Hann

2015-01-01

The Fire Regime Condition Class (FRCC) is a composite departure measure that compares current vegetation structure and fire regime to historical reference conditions. FRCC is computed as the average of: 1) Vegetation departure (VDEP) and 2) Regime (frequency and severity) departure (RDEP). In addition to the FRCC rating, the Vegetation Condition Class (VCC) and Regime...

Recent trends and changes in freshwater discharge into Hudson, James, and Ungava Bays

NASA Astrophysics Data System (ADS)

Déry, S. J.; Stieglitz, M.; McKenna, E.; Wood, E. F.

2004-05-01

Recent trends and changes in the observed river discharge into Hudson, James, and Ungava Bays (HJUBs) for the period 1964-1994 will be presented. Forty-two rivers with outlets into these bays contribute on average 700 cubic kilometers (= 0.02 sverdrups) of freshwater to the Arctic Ocean. River discharge attains a mean annual peak of 4.2 cubic kilometers per day on average each 17 June for the system as a whole, whereas the minimum of 0.6 cubic kilometers occurs on average each 3 April. The Nelson River supplies as much as 30% of the daily discharge for the entire system during winter, but diminishes in relative importance during spring and summer. Runoff rates per contributing area are highest (lowest) on the eastern (western) shores of Hudson and James Bays. Linear trend analyses reveal decreasing discharge in 38 out of the 42 rivers over the 31-year period. By 1994, the total annual freshwater discharge into the Arctic Ocean diminished by 110 cubic kilometers from its values in 1964, equivalent to a reduction of 0.0035 sverdrups. The annual peak discharge rates associated with snowmelt advanced by 16 days between 1964 and 1994 and has diminished slightly in intensity. There is a direct correlation between the time of this hydrological event and the latitude of a river's mouth; the timing of the peak discharge rates varies by 5 days for each degree of latitude. Continental snowmelt induces a seasonal pulse of freshwater from HJUBs that is tracked along its path into the Labrador Current and that coincides with ocean salinity anomalies on the inner Newfoundland Shelf. The talk will end with a discussion on the implications of a changing freshwater regime in HJUBs.

Modeling of dialogue regimes of distance robot control

NASA Astrophysics Data System (ADS)

Larkin, E. V.; Privalov, A. N.

2017-02-01

Process of distance control of mobile robots is investigated. Petri-Markov net for modeling of dialogue regime is worked out. It is shown, that sequence of operations of next subjects: a human operator, a dialogue computer and an onboard computer may be simulated with use the theory of semi-Markov processes. From the semi-Markov process of the general form Markov process was obtained, which includes only states of transaction generation. It is shown, that a real transaction flow is the result of «concurrency» in states of Markov process. Iteration procedure for evaluation of transaction flow parameters, which takes into account effect of «concurrency», is proposed.

Understanding discharge data uncertainty and its consequences for analyses of spatial and temporal change in hydrological response

NASA Astrophysics Data System (ADS)

Westerberg, Ida

2017-04-01

Understanding and quantifying how hydrological response behaviour varies across catchments, or how catchments change with time requires reliable discharge data. For reliable estimation of spatial and temporal change, the change in the response behaviour needs to be larger than the uncertainty in the response behaviour estimates that are compared. Understanding how discharge data uncertainty varies between catchments and over time, and how these uncertainties propagate to information derived from the data, is therefore key to drawing the right conclusions in comparative analyses. Uncertainty in discharge data is often highly place-specific and reliable estimation depends on detailed analyses of the rating curve model and stage-discharge measurements used to calculate discharge time series from stage (water level) at the gauging station. This underlying information is often not available when discharge data is provided by monitoring agencies. However, even without detailed analyses, the chance that the discharge data would be uncertain at particular flow ranges can be assessed based on information about the gauging station, the flow regime, and the catchment. This type of information is often available for most catchments even if the rating curve data are not. Such 'soft information' on discharge uncertainty may aid interpretation of results from regional and temporal change analyses. In particular, it can help reduce the risk of wrongly interpreting differences in response behaviour caused by discharge uncertainty as real changes. In this presentation I draw on several previous studies to discuss some of the factors that affect discharge data uncertainty and give examples from catchments worldwide. I aim to 1) illustrate the consequences of discharge data uncertainty on comparisons of different types of hydrological response behaviour across catchments and when analysing temporal change, and 2) give practical advice as to what factors may help identify catchments

Electrochemical cell with high discharge/charge rate capability

DOEpatents

Redey, Laszlo

1988-01-01

A fully charged positive electrode composition for an electrochemical cell includes FeS.sub.2 and NiS.sub.2 in about equal molar amounts along with about 2-20 mole percent of the reaction product Li.sub.2 S. Through selection of appropriate electrolyte compositions, high power output or low operating temperatures can be obtained. The cell includes a substantially constant electrode impedance through most of its charge and discharge range. Exceptionally high discharge rates and overcharge protection are obtainable through use of the inventive electrode composition.

Interactions between surface discharges induced by volume discharges in a dielectric barrier discharge system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Yenan; Dong, Lifang, E-mail: donglfhbu@163.com; Zhao, Longhu

2014-10-15

The interaction between micro-discharges involved in surface discharges (SDs) is studied in dielectric barrier discharge system. Instantaneous images taken by high speed cameras show that the SDs are induced by volume discharges (VDs). They cannot cross the midperpendicular of two neighbouring volume charges at low voltage while they stretch along it at high voltage, indicating that there is interaction between SDs. The differences of plasma parameters between SD and VD are studied by optical emission spectroscopy. The simulation of the electric fields of the wall charges accumulated by VD further confirms the existence of the interaction.

Electric arc discharge damage to ion thruster grids

NASA Technical Reports Server (NTRS)

Beebe, D. D.; Nakanishi, S.; Finke, R. C.

1974-01-01

Arcs representative of those occurring between the grids of a mercury ion thruster were simulated. Parameters affecting an arc and the resulting damage were studied. The parameters investigated were arc energy, arc duration, and grid geometry. Arc attenuation techniques were also investigated. Potentially serious damage occurred at all energy levels representative of actual thruster operating conditions. Of the grids tested, the lowest open-area configuration sustained the least damage for given conditions. At a fixed energy level a long duration discharge caused greater damage than a short discharge. Attenuation of arc current using various impedances proved to be effective in reducing arc damage. Faults were also deliberately caused using chips of sputtered materials formed during the operation of an actual thruster. These faults were cleared with no serious grid damage resulting using the principles and methods developed in this study.

Plasma Perturbations in High-Speed Probing of Hall Thruster Discharge Chambers: Quantification and Mitigation

NASA Technical Reports Server (NTRS)

Jorns, Benjamin A.; Goebel, Dan M.; Hofer, Richard R.

2015-01-01

An experimental investigation is presented to quantify the effect of high-speed probing on the plasma parameters inside the discharge chamber of a 6-kW Hall thruster. Understanding the nature of these perturbations is of significant interest given the importance of accurate plasma measurements for characterizing thruster operation. An array of diagnostics including a high-speed camera and embedded wall probes is employed to examine in real time the changes in electron temperature and plasma potential induced by inserting a high-speed reciprocating Langmuir probe into the discharge chamber. It is found that the perturbations onset when the scanning probe is downstream of the electron temperature peak, and that along channel centerline, the perturbations are best characterized as a downstream shift of plasma parameters by 15-20% the length of the discharge chamber. A parametric study is performed to investigate techniques to mitigate the observed probe perturbations including varying probe speed, probe location, and operating conditions. It is found that the perturbations largely disappear when the thruster is operated at low power and low discharge voltage. The results of this mitigation study are discussed in the context of recommended methods for generating unperturbed measurements of the discharge chamber plasma.

Psychiatric Discharge Process

PubMed Central

Alghzawi, Hamzah M.

2012-01-01

Background. Integration of research evidence into clinical nursing practice is essential for the delivery of high-quality nursing care. Discharge planning is an essential process in psychiatric nursing field, in order to prevent recurrent readmission to psychiatric units. Objective. The purpose of this paper is to perform literature overview on psychiatric discharge planning, in order to develop evidence-based practice guideline of psychiatric discharge plan. Methods. A search of electronic databases was conducted. The search process aimed to locate different levels of evidence. Inclusion criteria were studies including outcomes related to prevention of readmission as stability in the community, studies investigating the discharge planning process in acute psychiatric wards, and studies that included factors that impede discharge planning and factors that aid timely discharge. On the other hand, exclusion criteria were studies in which discharge planning was discussed as part of a multi faceted intervention and was not the main focus of the review. Result. Studies met inclusion criteria were mainly literature reviews, consensus statements, and descriptive studies. All of these studies are considered at the lower levels of evidence. Conclusion. This review demonstrated that discharge planning based on general principles (evidence based principles) should be applied during psychiatric discharge planning to make this discharge more effective. Depending on this review, it could be concluded that effective discharge planning includes main three stages; initial discharge meeting, regular discharge meeting(s), and leaving from hospital and discharge day. Each stage of them has requirements should be accomplished be go to the next stage. PMID:23762767

Thinning regimes and initial spacing for Eucalyptus plantations in Brazil.

PubMed

Ferraz Filho, Antonio C; Mola-Yudego, Blas; González-Olabarria, José R; Scolforo, José Roberto S

2018-01-01

This study focuses on the effects of different thinning regimes on clonal Eucalyptus plantations growth. Four different trials, planted in 1999 and located in Bahia and Espírito Santo States, were used. Aside from thinning, initial planting density, and post thinning fertilization application were also evaluated. Before canopy closure, and therefore before excessive competition between trees took place, it was found that stands planted under low densities (667 trees per hectare) presented a lower mortality proportion when compared to stand planted under higher densities (1111 trees per hectare). However, diameter growth prior to thinning operations was not statistically different between these two densities, presenting an overall mean of 4.9 cm/year. After canopy closure and the application of the thinning treatments, it was found that thinning regimes beginning early in the life of the stand and leaving a low number of residual trees presented the highest diameter and height growth. Unthinned treatments and thinning regimes late in the life of the stand (after 5.5 years), leaving a large number of residual trees presented the highest values of basal area production. The choice of the best thinning regime for Eucalyptus clonal material will vary according to the plantation objective.

Interaction between pulsed discharge and radio frequency discharge burst at atmospheric pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jie; College of Science, Donghua University, Shanghai 201620; Guo, Ying

The atmospheric pressure glow discharges (APGD) with dual excitations in terms of pulsed voltage and pulse-modulation radio frequency (rf) power are studied experimentally between two parallel plates electrodes. Pulse-modulation applied in rf APGD temporally separates the discharge into repetitive discharge bursts, between which the high voltage pulses are introduced to ignite sub-microsecond pulsed discharge. The discharge characteristics and spatio-temporal evolution are investigated by means of current voltage characteristics and time resolved imaging, which suggests that the introduced pulsed discharge assists the ignition of rf discharge burst and reduces the maintain voltage of rf discharge burst. Furtherly, the time instant ofmore » pulsed discharge between rf discharge bursts is manipulated to study the ignition dynamics of rf discharge burst.« less

Validating the MFiX-DEM Model for Flow Regime Prediction in a 3D Spouted Bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Subhodeep; Guenther, Chris; Rogers, William A.

The spout-fluidized bed reactor with relatively large oxygen carrier particles offers several advantages in chemical looping combustion operation using solid fuels. The large difference in size and weight between the oxygen carrier particles and the smaller coal or ash particles allows the oxygen carrier to be easily segregated for recirculation; the increased solids mixing due to dynamic flow pattern in the spout-fluidization regime prevents agglomeration. The primary objective in this work is to determine the effectiveness of the MFiX-DEM model in predicting the flow regime in a spouted bed. Successful validation of the code will allow the user to finemore » tune the operating conditions of a spouted bed to achieve the desired operating condition.« less

Collisional radiative model of an argon atmospheric capillary surface-wave discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yanguas-Gil, A.; Cotrino, J.; Gonzalez-Elipe, A.R.

2004-12-01

The characteristics of a microwave surface-wave sustained plasma operated at atmospheric pressure in an open-ended dielectric tube are investigated theoretically as a first step in the development of a self-consistent model for these discharges. The plasma column is sustained in flowing argon. A surface-wave discharge that fills the whole radial cross section of the discharge tube is considered. With experimental electron temperature profiles [Garcia et al., Spectrochim. Acta, Part B 55, 1733 (2000)] the numerical model is used to test the validity of the different approximations and to study the influence of the different kinetic processes and power loss mechanismsmore » on the discharge.« less

Does activity limitation predict discharge destination for postacute care patients?

PubMed

Chang, Feng-Hang; Ni, Pengsheng; Jette, Alan M

2014-09-01

This study aimed to examine the ability of different domains of activity limitation to predict discharge destination (home vs. nonhome settings) 1 mo after hospital discharge for postacute rehabilitation patients. A secondary analysis was conducted using a data set of 518 adults with neurologic, lower extremity orthopedic, and complex medical conditions followed after discharge from a hospital into postacute care. Variables collected at baseline include activity limitations (basic mobility, daily activity, and applied cognitive function, measured by the Activity Measure for Post-Acute Care), demographics, diagnosis, and cognitive status. The discharge destination was recorded at 1 mo after being discharged from the hospital. Correlational analyses revealed that the 1-mo discharge destination was correlated with two domains of activity (basic mobility and daily activity) and cognitive status. However, multiple logistic regression and receiver operating characteristic curve analyses showed that basic mobility functioning performed the best in discriminating home vs. nonhome living. This study supported the evidence that basic mobility functioning is a critical determinant of discharge home for postacute rehabilitation patients. The Activity Measure for Post-Acute Care-basic mobility showed good usability in discriminating home vs. nonhome living. The findings shed light on the importance of basic mobility functioning in the discharge planning process.

Endoreversible quantum heat engines in the linear response regime.

PubMed

Wang, Honghui; He, Jizhou; Wang, Jianhui

2017-07-01

We analyze general models of quantum heat engines operating a cycle of two adiabatic and two isothermal processes. We use the quantum master equation for a system to describe heat transfer current during a thermodynamic process in contact with a heat reservoir, with no use of phenomenological thermal conduction. We apply the endoreversibility description to such engine models working in the linear response regime and derive expressions of the efficiency and the power. By analyzing the entropy production rate along a single cycle, we identify the thermodynamic flux and force that a linear relation connects. From maximizing the power output, we find that such heat engines satisfy the tight-coupling condition and the efficiency at maximum power agrees with the Curzon-Ahlborn efficiency known as the upper bound in the linear response regime.

Design of a fast computer-based partial discharge diagnostic system

NASA Technical Reports Server (NTRS)

Oliva, Jose R.; Karady, G. G.; Domitz, Stan

1991-01-01

Partial discharges cause progressive deterioration of insulating materials working in high voltage conditions and may lead ultimately to insulator failure. Experimental findings indicate that deterioration increases with the number of discharges and is consequently proportional to the magnitude and frequency of the applied voltage. In order to obtain a better understanding of the mechanisms of deterioration produced by partial discharges, instrumentation capable of individual pulse resolution is required. A new computer-based partial discharge detection system was designed and constructed to conduct long duration tests on sample capacitors. This system is capable of recording large number of pulses without dead time and producing valuable information related to amplitude, polarity, and charge content of the discharges. The operation of the system is automatic and no human supervision is required during the testing stage. Ceramic capacitors were tested at high voltage in long duration tests. The obtained results indicated that the charge content of partial discharges shift towards high levels of charge as the level of deterioration in the capacitor increases.

Study of the catastrophic discharge phenomenon in a Hall thruster

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Su, Hongbo; Li, Peng; Wei, Liqiu; Li, Hong; Peng, Wuji; Xu, Yu; Sun, Hezhi; Yu, Daren

2017-10-01

In a 1350-W Hall-effect thruster, in which a technique for pushing down the magnetic field is implemented, a catastrophic discharge phenomenon is identified by varying the magnetic field strength while keeping all other operating parameters constant. According to experiments, before and after the discharge catastrophe, the plume changes from focusing state to a divergent state, and discharge parameters such as discharge current and thrust exhibit noticeable changes. The divergence half-angle of the plume increases from 22° to 46°. The oscillation amplitude and mean values of the discharge current significantly increase from 0.8 A to 4 A and from 4.6 A to 6.3 A, respectively, while the thrust increases from 89.3 mN to 91 mN. Analysis of the experimental results shows that as the maximum magnetic field of the thruster we developed is in the plume region, the acceleration occurs in the plume region and a large number of Xe2+ ions appear in the plume area, the catastrophic discharge phenomenon observed.

Lognormal firing rate distribution reveals prominent fluctuation–driven regime in spinal motor networks

PubMed Central

Petersen, Peter C; Berg, Rune W

2016-01-01

When spinal circuits generate rhythmic movements it is important that the neuronal activity remains within stable bounds to avoid saturation and to preserve responsiveness. Here, we simultaneously record from hundreds of neurons in lumbar spinal circuits of turtles and establish the neuronal fraction that operates within either a ‘mean-driven’ or a ‘fluctuation–driven’ regime. Fluctuation-driven neurons have a ‘supralinear’ input-output curve, which enhances sensitivity, whereas the mean-driven regime reduces sensitivity. We find a rich diversity of firing rates across the neuronal population as reflected in a lognormal distribution and demonstrate that half of the neurons spend at least 50 % of the time in the ‘fluctuation–driven’ regime regardless of behavior. Because of the disparity in input–output properties for these two regimes, this fraction may reflect a fine trade–off between stability and sensitivity in order to maintain flexibility across behaviors. DOI: http://dx.doi.org/10.7554/eLife.18805.001 PMID:27782883

Feedback-Assisted Extension of the Tokamak Operating Space to Low Safety Factor

NASA Astrophysics Data System (ADS)

Hanson, J. M.

2013-10-01

Recent DIII-D experiments have demonstrated stable operation at very low edge safety factor, q95 <~ 2 through the use of magnetic feedback to control the n = 1 resistive wall mode (RWM) instability. The performance of tokamak fusion devices may benefit from increased plasma current, and thus, decreased q. However, disruptive stability limits are commonly encountered in experiments at qedge ~ 2 (limited plasmas) and q95 ~ 2 (diverted plasmas), limiting exploration of low q regimes. In the recent DIII-D experiments, the impact and control of key disruptive instabilities was studied. Locked n = 1 modes with exponential growth times on the order of the wall eddy current decay timescale τw preceded disruptions at q95 = 2 . The instabilities have a poloidal structure that is consistent with VALEN simulations of the RWM mode structure at q95 = 2 . Applying proportional gain magnetic feedback control of the n = 1 mode resulted in stabilized operation with q95 reaching 1.9, and an extension of the discharge lifetime for > 100τw . Loss of feedback control was accompanied by power supply saturation, followed by a rapidly growing n = 1 mode and disruption. Comparisons of the feedback dynamics with VALEN simulations will be presented. The DIII-D results complement and will be discussed alongside recent RFX-MOD demonstrations of RWM control using magnetic feedback in limited tokamak discharges with qedge < 2. These results call attention to the utility of magnetic feedback in significantly extending the tokamak operational space and potentially opening a new route to economical fusion power production. Supported by the US Department of Energy under DE-FG02-04ER54761 and DE-FC02-04ER54698.

Demonstration of a high repetition rate capillary discharge waveguide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonsalves, A. J., E-mail: ajgonsalves@lbl.gov; Pieronek, C.; Daniels, J.

2016-01-21

A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources.

Dynamic photolytical actinometry of the vacuum-ultraviolet radiation produced by multichannel surface discharges of submicrosecond duration.

PubMed

Tcheremiskine, V I; Uteza, O P; Sentis, M L; Mikheev, L D

2007-06-01

Absolute measurements of the vacuum-ultraviolet (VUV) radiation power produced by a planar broadband optical source of submicrosecond light pulse duration are carried out in the transient regime of formation of a photodissociation (bleaching) wave in a photodecomposing absorptive medium. The source is based on a multichannel surface discharge initiated in ArN(2) gas mixtures on the area of approximately 0.1 m(2). The energetic characteristics of the produced VUV radiation are determined on the basis of spatially and temporally resolved observations of the pulsed photolysis of XeF(2) vapors. It is shown that the photon flux intensity produced by the source within the spectral range of 120-200 nm reaches 1.1 x 10(23) photonscm(2) s corresponding to the effective brightness temperature of discharge plasma of 20 kK and to the intrinsic efficiency of the discharge VUV emission of 3.2%. Numerical simulations of the photolysis process show a rather weak sensitivity of the results to the fraction of discharge radiation emitted into the line spectrum, as well as to the angular distribution of emitted radiation. The spectral band of measurements can be selected according to the choice of parent photodecomposing particles.

Ventriculoperitoneal shunt - discharge

MedlinePlus

... ventriculoperitoneal - discharge; VP shunt - discharge; Shunt revision - discharge; Hydrocephalus shunt placement - discharge ... Your child has hydrocephalus and needed a shunt placed to drain excess fluid and relieve pressure in the brain. This buildup of brain ...

Bone marrow transplant - discharge

MedlinePlus

Transplant - bone marrow - discharge; Stem cell transplant - discharge; Hematopoietic stem cell transplant - discharge; Reduced intensity; Non-myeloablative transplant - discharge; Mini transplant - discharge; Allogenic bone marrow transplant - discharge; ...

Estimated discharge of treated wastewater in Florida, 1990

USGS Publications Warehouse

Marella, R.L.

1994-01-01

According to the Florida Department of Environ- mental Protection, 5,100 wastewater treatment systems were in operation during 1990. Of this total, 72 percent were domestic wastewater facilities and 28 percent were industrial waste- water facilities. The number of wastewater systems inventoried for 1990 was 1,062 (systems that treated and discharged more than 0.01 Mgal/d or had a plant capacity of greater than 0.04 Mgal/d. Based on this inventory, the estimated discharge of treated wastewater in Florida during 1990 totaled 1,638 million gallons per day. Approxi- mately 65 percent of this water was discharged to surface water during 1990 and the remaining 35 percent was discharged to ground water. Discharge to surface water includes effluent outfalls into the Atlantic Ocean (32 percent), while the re- maining (68 percent) is discharged into the Gulf of Mexico, bays, rivers, wetlands, and other surface water bodies throughout Florida. Discharge to ground-water includes treated effluent outfalls to land application systems (reuse systems and spray fields), drain fields, percolation ponds (51 percent), and to injection wells (49 percent). An estimated 322 million gallons per day of the treated domestic and industrial wastewater was reused during 1990. Discharge of treated domestic wastewater from the 994 systems inventoried in Florida during 1990 totaled 1,353 million gallons per day and served an estimated 8.58 million people (66 percent of the population of Florida in 1990). The remaining 34 percent of the popu- lation (4.36 million) are served by the 2,700 smaller domestic wastewater systems or have individual septic tanks. In 1990, there were 1.56 million septic tanks in Florida. Discharge of industrial wastewater was inventoried for 68 systems in 1990 and totaled 285 million gallons per day. Discharge of domestic wastewater in- creased more than 20 percent and industrial wastewater discharge increased 5 percent from 1985 to 1990. (USGS)

Vibrational and Rotational CARS Measurements of Nitrogen in Afterglow of Streamer Discharge in Atmospheric Pressure Fuel/Air Mixtures

DTIC Science & Technology

2012-01-01

in a variety of different ignition regimes, including pulsed detonation engines ( PDEs ) and automobile engines, with experiments demonstrating TPI to...Vibrational and rotational CARS measurements of nitrogen in afterglow of streamer discharge in atmospheric pressure fuel/air mixtures This article...DATE 2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Vibrational and rotational CARS measurements of

Gallbladder removal - laparoscopic - discharge

MedlinePlus

Cholecystectomy laparoscopic - discharge; Cholelithiasis - laparoscopic discharge; Biliary calculus - laparoscopic discharge; Gallstones - laparoscopic discharge; Cholecystitis - laparoscopic discharge

Pediatric heart surgery - discharge

MedlinePlus

... of the aorta repair - discharge; Heart surgery for children - discharge; Atrial septal defect repair - discharge; Ventricular septal ... discharge; Acquired heart disease - discharge; Heart valve surgery - ... Heart surgery - pediatric - discharge; Heart transplant - pediatric - ...

Turbulent transport regimes and the SOL heat flux width

NASA Astrophysics Data System (ADS)

Myra, J. R.; D'Ippolito, D. A.; Russell, D. A.

2014-10-01

Understanding the responsible mechanisms and resulting scaling of the scrape-off layer (SOL) heat flux width is important for predicting viable operating regimes in future tokamaks, and for seeking possible mitigation schemes. Simulation and theory results using reduced edge/SOL turbulence models have produced SOL widths and scalings in reasonable accord with experiments in many cases. In this work, we attempt to qualitatively and conceptually understand various regimes of edge/SOL turbulence and the role of turbulent transport in establishing the SOL heat flux width. Relevant considerations include the type and spectral characteristics of underlying instabilities, the location of the gradient drive relative to the SOL, the nonlinear saturation mechanism, and the parallel heat transport regime. Recent SOLT turbulence code results are employed to understand the roles of these considerations and to develop analytical scalings. We find a heat flux width scaling with major radius R that is generally positive, consistent with older results reviewed in. The possible relationship of turbulence mechanisms to the heuristic drift mechanism is considered, together with implications for future experiments. Work supported by US DOE grant DE-FG02-97ER54392.

Effects of local climate and hydrological conditions on the thermal regime of a reservoir at Tropic of Cancer, in southern China.

PubMed

Wang, Sheng; Qian, Xin; Han, Bo-Ping; Luo, Lian-Cong; Hamilton, David P

2012-05-15

Thermal regime is strongly associated with hydrodynamics in water, and it plays an important role in the dynamics of water quality and ecosystem succession of stratified reservoirs. Changes in both climate and hydrological conditions can modify thermal regimes. Liuxihe Reservoir (23°45'50″N; 113°46'52″E) is a large, stratified and deep reservoir in Guangdong Province, located at the Tropic of Cancer of southern China. The reservoir is a warm monomictic water body with a long period of summer stratification and a short period of mixing in winter. The vertical distribution of suspended particulate material and nutrients are influenced strongly by the thermal structure and the associated flow fields. The hypolimnion becomes anoxic in the stratified period, increasing the release of nutrients from the bottom sediments. Fifty-one years of climate and reservoir operational observations are used here to show the marked changes in local climate and reservoir operational schemes. The data show increasing air temperature and more violent oscillations in inflow volumes in the last decade, while the inter-annual water level fluctuations tend to be more moderate. To quantify the effects of changes in climate and hydrological conditions on thermal structure, we used a numerical simulation model to create scenarios incorporating different air temperatures, inflow volumes, and water levels. The simulations indicate that water column stability, the duration of the mixing period, and surface and outflow temperatures are influenced by both natural factors and by anthropogenic factors such as climate change and reservoir operation schemes. Under continuous warming and more stable storage in recent years, the simulations indicate greater water column stability and increased duration of stratification, while irregular large discharge events may reduce stability and lead to early mixing in autumn. Our results strongly suggest that more attention should be focused on water quality

Vessel Sewage Discharges: No-Discharge Zones (NDZs)

EPA Pesticide Factsheets

States may petition the EPA to establish areas, called no discharge zones (NDZs), where vessel sewage discharges are prohibited. This page describes how NDZs are designated, the types of designations, who enforces them, and how to comply.

Comprehension and compliance with the discharge advice and quality of life at home among the postoperative neurosurgery patients discharged from PGIMER, Chandigarh, India

PubMed Central

Kumar, Vishal; Singh, Amarjeet; Tewari, Manoj K.; Kaur, Sukhpal

2016-01-01

Problem Statement: Neurosurgical patients require special care not only in the hospital but also after their discharge from the hospital. Comprehension and compliance to the instructions given by the doctors/nurses at the time of discharge is important in home care of these patients. Many such patients suffer from various co-morbidities. Variable periods of convalescence affect health-related quality of life in these patients. Purpose of the Study: To determine the degree of compliance of neurosurgery patients and their family caregivers with the discharge advice given by the consultantsTo evaluate the quality of life of these patientsTo know the problems faced by these patients at home. Materials and Methods: This cross-sectional interview-based descriptive study was conducted in 2010 in Chandigarh. These patients were visited at their home. A scale was evolved to evaluate comprehension and compliance to the advice given at the time of discharge, according to the criteria developed by Clark et al. Lawton Brody instrumental activity of daily life and Spitzer quality of life index were used to assess patients' quality of life after the operation. Verbatim responses were recorded for the purpose of qualitative research. Results: Overall, 58 patients and their caregivers were interviewed at home. Mean age of the patients was 38.9 years. Out of 37 patients, 35 showed good comprehension and 33 patients had a good compliance with the instructions given for medication. The condition of 74.1% patients improved after the operation. Depression was reported in 31% of the patients. Many (36.2%) patients had to quit their job due to the disease. Almost half (47.4%) of the patients were independent in daily activities of their life while being evaluated on Barthel activity of daily life index. Conclusion and Recommendations: It is in the long term that the true complexity and impact of operations become apparent. After operation, such patients are likely to have a range of

Mode transition of a Hall thruster discharge plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hara, Kentaro, E-mail: kenhara@umich.edu; Sekerak, Michael J., E-mail: msekerak@umich.edu; Boyd, Iain D.

2014-05-28

A Hall thruster is a cross-field plasma device used for spacecraft propulsion. An important unresolved issue in the development of Hall thrusters concerns the effect of discharge oscillations in the range of 10–30 kHz on their performance. The use of a high speed Langmuir probe system and ultra-fast imaging of the discharge plasma of a Hall thruster suggests that the discharge oscillation mode, often called the breathing mode, is strongly correlated to an axial global ionization mode. Stabilization of the global oscillation mode is achieved as the magnetic field is increased and azimuthally rotating spokes are observed. A hybrid-direct kinetic simulationmore » that takes into account the transport of electronically excited atoms is used to model the discharge plasma of a Hall thruster. The predicted mode transition agrees with experiments in terms of the mean discharge current, the amplitude of discharge current oscillation, and the breathing mode frequency. It is observed that the stabilization of the global oscillation mode is associated with reduced electron transport that suppresses the ionization process inside the channel. As the Joule heating balances the other loss terms including the effects of wall loss and inelastic collisions, the ionization oscillation is damped, and the discharge oscillation stabilizes. A wide range of the stable operation is supported by the formation of a space charge saturated sheath that stabilizes the electron axial drift and balances the Joule heating as the magnetic field increases. Finally, it is indicated from the numerical results that there is a strong correlation between the emitted light intensity and the discharge current.« less

Wall conditioning by ECRH discharges and He-GDC in the limiter phase of Wendelstein 7-X

NASA Astrophysics Data System (ADS)

Wauters, T.; Brakel, R.; Brezinsek, S.; Dinklage, A.; Goriaev, A.; Laqua, H. P.; Marsen, S.; Moseev, D.; Stange, T.; Schlisio, G.; Pedersen, T. Sunn; Volzke, O.; Wenzel, U.; the W7-X Team

2018-06-01

Wendelstein 7-X (W7-X) relies on wall conditioning to control the density and the impurity content of the plasma. Wall conditioning in the first operation campaign of W7-X consisted of baking at 150 °C during 1 week prior to operation, glow discharge conditioning (GDC) in helium (He) and electron cyclotron resonance heating (ECRH) discharges. Additionally, the usage of He-GDC was limited to avoid sputtering and migration of metallic plasma facing components. This presented a unique opportunity for studying the applicability of ECRH discharges for initial wall conditioning on a stellarator, albeit in the carbon limiter configuration. A single envelope curve is observed in the normalised outgassing data that takes into account all ECRH discharges. This illustrates that the majority of discharges operates at the limits of a radiative collapse. Hydrogen recycling dominated the fuelling of ECRH discharges throughout while CO outgassing was found strongest at the start of the campaign. A reduction of recycling was observed throughout the campaign. Temporarily depleting the walls from H and impurities was possible by He-GDC. It was shown that the recycling coefficient in -ECRH plasmas could be reduced and the pulse duration significantly extended by He-’recovery’ ECRH plasmas. Good wall conditions were defined by normalised outgassing values below mbar kJ‑1. In absence of -GDC, more than 311 cumulated discharge seconds of ECRH discharges are needed for obtaining lasting low outgassing levels. A release model with two trapping reservoirs could reproduce the normalised outgassing trend, including ECRH and GDC plasma wall interactions.

Determination of discharge during pulsating flow

USGS Publications Warehouse

Thompson, T.H.

1968-01-01

Pulsating flow in an open channel is a manifestation of unstable-flow conditions in which a series of translatory waves of perceptible magnitude develops and moves rapidly downstream. Pulsating flow is a matter of concern in the design and operation of steep-gradient channels. If it should occur at high stages in a channel designed for stable flow, the capacity of the channel may be inadequate at a discharge that is much smaller than that for which the channel was designed. If the overriding translatory wave carries an appreciable part of the total flow, conventional stream-gaging procedures cannot be used to determine the discharge; neither the conventional instrumentation nor conventional methodology is adequate. A method of determining the discharge during pulsating flow was tested in the Santa Anita Wash flood control channel in Arcadia, Calif., April 16, 1965. Observations of the dimensions and velocities of translatory waves were made during a period of controlled reservoir releases of about 100, 200, and 300 cfs (cubic feet per second). The method of computing discharge was based on (1) computation of the discharge in the overriding waves and (2) computation of the discharge in the shallow-depth, or overrun, part of the flow. Satisfactory results were obtained by this method. However, the procedure used-separating the flow into two components and then treating the shallow-depth component as though it were steady--has no theoretical basis. It is simply an expedient for use until laboratory investigation can provide a satisfactory analytical solution to the problem of computing discharge during pulsating flow. Sixteen months prior to the test in Santa Anita Wash, a robot camera had been designed .and programmed to obtain the data needed to compute discharge by the method described above. The photographic equipment had been installed in Haines Creek flood control channel in Los Angeles, Calif., but it had not been completely tested because of the infrequency of

Ion density evolution in a high-power sputtering discharge with bipolar pulsing

NASA Astrophysics Data System (ADS)

Britun, N.; Michiels, M.; Godfroid, T.; Snyders, R.

2018-06-01

Time evolution of sputtered metal ions in high power impulse magnetron sputtering (HiPIMS) discharge with a positive voltage pulse applied after a negative one (regime called "bipolar pulse HiPIMS"—BPH) is studied using 2-D density mapping. It is demonstrated that the ion propagation dynamics is mainly affected by the amplitude and duration of the positive pulse. Such effects as ion repulsion from the cathode and the ionization zone shrinkage due to electron drift towards the cathode are clearly observed during the positive pulse. The BPH mode also alters the film crystallographic structure, as observed from X-ray diffraction analysis.

Effect of land cover, stream discharge, and precipitation on water quality in Puerto Rico

NASA Astrophysics Data System (ADS)

Hall, J. S.; Uriarte, M.

2017-12-01

In 2015, Puerto Rico experienced one of the worst droughts in its history, causing widespread water rationing and sparking concerns for future resources. The drought represents precipitation extremes that provide valuable insight into the effects of land cover (LC), on modulating discharge and water quality indices at varying spatial scales. We used data collected from 38 water quality and 55 precipitation monitoring stations in Puerto Rico from 2005 to 2016, paired with a 2010 land cover map to (1) determine whether temporal variability in discharge, precipitation, or antecedent precipitation was a better predictor of water quality, (2) find the spatial scale where LC has the greatest impact on water quality, and (3) quantify impacts of LC on water quality indices, including dissolved oxygen (mg/L), total nitrogen (mg/L), phosphorous (mg/L), turbidity (NTRU), fecal coliforms (colony units/100mL) and instantaneous discharge (ft3/s). The resulting linear mixed effects models account for between 36-68% of the variance in water quality. Preliminary results indicate that phosphorous and nitrogen were best predicted from instantaneous stream discharge, the log of discharge was the better predictor for turbidity and fecal coliforms, and summed 2 and 14-day antecedent precipitation indices were better predictors for dissolved oxygen and discharge, respectively. Increased urban and pasture area reliably decreased water quality in relation to forest cover, while agriculture and wetlands had little or mixed effects. Turbidity and nitrogen responded to a watershed level LC, while phosphorous, fecal coliforms, and discharge responded to LC in 60 m riparian buffers at the watershed scale. Our results indicate that LC modulates changing precipitation regimes and the ensuing impacts on water quality at a range of spatial scales.

Experimental observation of the inductive electric field and related plasma nonuniformity in high frequency capacitive discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, S. K.; Chang, H. Y.

To elucidate plasma nonuniformity in high frequency capacitive discharges, Langmuir probe and B-dot probe measurements were carried out in the radial direction in a cylindrical capacitive discharge driven at 90 MHz with argon pressures of 50 and 400 mTorr. Through the measurements, a significant inductive electric field (i.e., time-varying magnetic field) was observed at the radial edge, and it was found that the inductive electric field creates strong plasma nonuniformity at high pressure operation. The plasma nonuniformity at high pressure operation is physically similar to the E-H mode transition typically observed in inductive discharges. This result agrees well with themore » theories of electromagnetic effects in large area and/or high frequency capacitive discharges.« less

Improved Confinement Regimes and the Ignitor Experiment

NASA Astrophysics Data System (ADS)

Bombarda, F.; Coppi, B.; Detragiache, P.

2013-10-01

The Ignitor experiment is the only one designed and planned to reach ignition under controlled DT burning conditions. The machine prameters have been established on the basis of existing knowledge of the confinement properties of high density plasmas. The optimal plasma evolution in order to reach ignition by means of Ohmic heating only, without the contribution of transport barriers has been identified. Improved confinement regimes are expected to be accessible by means of the available ICRH additional heating power and the injection of pellets for density profile control. Moreover, ECRH of the outer edge of the (toroidal) plasma column has been proposed using very high frequency sources developed in Russia. Ignition can then be reached at slightly reduced machine parameters. Significant exploration of the behavior of burning, sub-ignited plasmas can be carried out in less demanding operational conditions than those needed for ignition with plasmas accessing the I or H-regimes. These conditions will be discussed together with the provisions made in order to maintain the required (for ignition) degree of plasma purity. Sponsored in part by the U.S. DOE.

46 CFR 153.964 - Discharge by gas pressurization.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Discharge by gas pressurization. 153.964 Section 153.964 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer...

46 CFR 153.964 - Discharge by gas pressurization.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Discharge by gas pressurization. 153.964 Section 153.964 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer...

46 CFR 153.964 - Discharge by gas pressurization.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Discharge by gas pressurization. 153.964 Section 153.964 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer...

46 CFR 153.964 - Discharge by gas pressurization.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Discharge by gas pressurization. 153.964 Section 153.964 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer...

46 CFR 153.964 - Discharge by gas pressurization.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Discharge by gas pressurization. 153.964 Section 153.964 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer...

Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter.

PubMed

Vizir, A V; Tyunkov, A V; Shandrikov, M V; Oks, E M

2010-02-01

The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10(9) cm(-3) at an operating gas pressure in the vacuum chamber of less than 2x10(-2) Pa. The device features high power efficiency, design simplicity, and compactness.

Study of Plasma Flows Generated in Plasma Focus Discharge in Different Regimes of Working Gas Filling

NASA Astrophysics Data System (ADS)

Voitenko, D. A.; Ananyev, S. S.; Astapenko, G. I.; Basilaia, A. D.; Markolia, A. I.; Mitrofanov, K. N.; Myalton, V. V.; Timoshenko, A. P.; Kharrasov, A. M.; Krauz, V. I.

2017-12-01

Results are presented from experimental studies of the plasma flows generated in the KPF-4 Phoenix Mather-type plasma focus device (Sukhum Physical Technical Institute). In order to study how the formation and dynamics of the plasma flow depend on the initial distribution of the working gas, a system of pulsed gas puffing into the discharge volume was developed. The system allows one to create profiled gas distributions, including those with a reduced gas density in the region of plasma flow propagation. Results of measurements of the magnetic field, flow profile, and flow deceleration dynamics at different initial distributions of the gas pressure are presented.

Online recognition of the multiphase flow regime and study of slug flow in pipeline

NASA Astrophysics Data System (ADS)

Liejin, Guo; Bofeng, Bai; Liang, Zhao; Xin, Wang; Hanyang, Gu

2009-02-01

Multiphase flow is the phenomenon existing widely in nature, daily life, as well as petroleum and chemical engineering industrial fields. The interface structure among multiphase and their movement are complicated, which distribute random and heterogeneously in the spatial and temporal scales and have multivalue of the flow structure and state[1]. Flow regime is defined as the macro feature about the multiphase interface structure and its distribution, which is an important feature to describe multiphase flow. The energy and mass transport mechanism differ much for each flow regimes. It is necessary to solve the flow regime recognition to get a clear understanding of the physical phenomena and their mechanism of multiphase flow. And the flow regime is one of the main factors affecting the online measurement accuracy of phase fraction, flow rate and other phase parameters. Therefore, it is of great scientific and technological importance to develop new principles and methods of multiphase flow regime online recognition, and of great industrial background. In this paper, the key reasons that the present method cannot be used to solve the industrial multiphase flow pattern recognition are clarified firstly. Then the prerequisite to realize the online recognition of multiphase flow regime is analyzed, and the recognition rules for partial flow pattern are obtained based on the massive experimental data. The standard templates for every flow regime feature are calculated with self-organization cluster algorithm. The multi-sensor data fusion method is proposed to realize the online recognition of multiphase flow regime with the pressure and differential pressure signals, which overcomes the severe influence of fluid flow velocity and the oil fraction on the recognition. The online recognition method is tested in the practice, which has less than 10 percent measurement error. The method takes advantages of high confidence, good fault tolerance and less requirement of

Characterization of high power impulse magnetron sputtering discharges

NASA Astrophysics Data System (ADS)

Hala, Matej

Paper I: In the first paper, we present a new approach in the characterization of the high power pulsed magnetron sputtering (HiPIMS) discharge evolution—time- and species-resolved plasma imaging—employing a set of band-pass optical interference filters suitable for the isolation of the emission originating from different species populating the plasma. We demonstrate that the introduction of such filters can be used to distinguish different phases of the discharge, and to visualize numerous plasma effects including background gas excitations during the discharge ignition, gas shock waves, and expansion of metal-rich plasmas. In particular, the application of this technique is shown on the diagnostics of the 200 µs long non-reactive HiPIMS discharges using a Cr target. Paper II: In order to gain further information about the dynamics of reactive HiPIMS discharges, both fast plasma imaging and time- and space-resolved optical emission spectroscopy (OES) are used for a systematic investigation of the 200 µs long HiPIMS pulses operated in Ar, N2 and N 2/Ar mixtures and at various pressures. It is observed that the dense metal plasma created next to the target propagates in the reactor at a speed ranging from 0.7 to 3.5 km s-1, depending on the working gas composition and the pressure. In fact, it increases with higher N 2 concentration and with lower pressure. The visible form of the propagating plasma wave changes from a hemispherical shape in Ar to a drop-like shape extending far from the target with increasing N2 concentration, owing to the significant emission from molecular N2. Interestingly, the evidence of the target self-sputtering is found for all investigated conditions, including pure N2 atmosphere. Paper III: Here, we report on the time- and species-resolved plasma imaging analysis of the dynamics of the 200 µs long HiPIMS discharges above a Cr target ignited in pure O2. It is shown that the discharge emission is dominated solely by neutral and

Alfvén oscillations in ohmic discharges with runaway electrons in the TUMAN-3M tokamak

NASA Astrophysics Data System (ADS)

Tukachinsky, A. S.; Askinazi, L. G.; Balachenkov, I. M.; Belokurov, A. A.; Gin, D. B.; Zhubr, N. A.; Kornev, V. A.; Lebedev, S. V.; Khil'kevich, E. M.; Chugunov, I. N.; Shevelev, A. E.

2016-12-01

Studying the mechanism of Alfvén wave generation in plasma is important, since the interaction of these waves with energetic particles in tokamak-type reactors can increase the losses of energy and particles with the corresponding decrease in the efficiency of plasma heating and, under certain conditions, lead to the damage of structural elements of the system. Despite the previous detailed investigations of the excitation of Alfvén waves by superthermal particles in regimes with additional heating, the physics of Alfvén mode generation in discharges with ohmic heating of plasma is still not sufficiently studied. We have established that a significant factor inf luencing the development of Alfvén oscillations in ohmic discharge is the presence of runaway electrons. A physical mechanism explaining this relationship is proposed.

Hospital-based, acute care after ambulatory surgery center discharge.

PubMed

Fox, Justin P; Vashi, Anita A; Ross, Joseph S; Gross, Cary P

2014-05-01

As a measure of quality, ambulatory surgery centers have begun reporting rates of hospital transfer at discharge. This process, however, may underestimate the acute care needs of patients after care. We conducted this study to determine rates and evaluate variation in hospital transfer and hospital-based, acute care within 7 days among patients discharged from ambulatory surgery centers. Using data from the Healthcare Cost and Utilization Project, we identified adult patients who underwent a medical or operative procedure between July 2008 and September 2009 at ambulatory surgery centers in California, Florida, and Nebraska. The primary outcomes were hospital transfer at the time of discharge and hospital-based, acute care (emergency department visits or hospital admissions) within 7-days expressed as the rate per 1,000 discharges. At the ambulatory surgery center level, rates were adjusted for age, sex, and procedure-mix. We studied 3,821,670 patients treated at 1,295 ambulatory surgery centers. At discharge, the hospital transfer rate was 1.1 per 1,000 discharges (95% confidence interval 1.1-1.1). Among patients discharged home, the hospital-based, acute care rate was 31.8 per 1,000 discharges (95% confidence interval 31.6-32.0). Across ambulatory surgery centers, there was little variation in adjusted hospital transfer rates (median = 1.0/1,000 discharges [25th-75th percentile = 1.0-2.0]), whereas substantial variation existed in adjusted, hospital-based, acute care rates (28.0/1,000 [21.0-39.0]). Among adult patients undergoing ambulatory care at surgery centers, hospital transfer at time of discharge from the ambulatory care center is a rare event. In contrast, the rate of need for hospital-based, acute care in the first week afterwards is nearly 30-fold greater, varies across centers, and may be a more meaningful measure for discriminating quality. Published by Mosby, Inc.

Dynamic Discharge Arc Driver. [computerized simulation

NASA Technical Reports Server (NTRS)

Dannenberg, R. E.; Slapnicar, P. I.

1975-01-01

A computer program using nonlinear RLC circuit analysis was developed to accurately model the electrical discharge performance of the Ames 1-MJ energy storage and arc-driver system. Solutions of circuit parameters are compared with experimental circuit data and related to shock speed measurements. Computer analysis led to the concept of a Dynamic Discharge Arc Driver (DDAD) capable of increasing the range of operation of shock-driven facilities. Utilization of mass addition of the driver gas offers a unique means of improving driver performance. Mass addition acts to increase the arc resistance, which results in better electrical circuit damping with more efficient Joule heating, producing stronger shock waves. Preliminary tests resulted in an increase in shock Mach number from 34 to 39 in air at an initial pressure of 2.5 torr.

GAS DISCHARGE DEVICES

DOEpatents

Arrol, W.J.; Jefferson, S.

1957-08-27

The construction of gas discharge devices where the object is to provide a gas discharge device having a high dark current and stabilized striking voltage is described. The inventors have discovered that the introduction of tritium gas into a discharge device with a subsequent electrical discharge in the device will deposit tritium on the inside of the chamber. The tritium acts to emit beta rays amd is an effective and non-hazardous way of improving the abovementioned discharge tube characteristics

Application of the gravity search algorithm to multi-reservoir operation optimization

NASA Astrophysics Data System (ADS)

Bozorg-Haddad, Omid; Janbaz, Mahdieh; Loáiciga, Hugo A.

2016-12-01

Complexities in river discharge, variable rainfall regime, and drought severity merit the use of advanced optimization tools in multi-reservoir operation. The gravity search algorithm (GSA) is an evolutionary optimization algorithm based on the law of gravity and mass interactions. This paper explores the GSA's efficacy for solving benchmark functions, single reservoir, and four-reservoir operation optimization problems. The GSA's solutions are compared with those of the well-known genetic algorithm (GA) in three optimization problems. The results show that the GSA's results are closer to the optimal solutions than the GA's results in minimizing the benchmark functions. The average values of the objective function equal 1.218 and 1.746 with the GSA and GA, respectively, in solving the single-reservoir hydropower operation problem. The global solution equals 1.213 for this same problem. The GSA converged to 99.97% of the global solution in its average-performing history, while the GA converged to 97% of the global solution of the four-reservoir problem. Requiring fewer parameters for algorithmic implementation and reaching the optimal solution in fewer number of functional evaluations are additional advantages of the GSA over the GA. The results of the three optimization problems demonstrate a superior performance of the GSA for optimizing general mathematical problems and the operation of reservoir systems.

Which Patients Require Extended Thromboprophylaxis After Colectomy? Modeling Risk and Assessing Indications for Post-discharge Pharmacoprophylaxis.

PubMed

Beal, Eliza W; Tumin, Dmitry; Chakedis, Jeffery; Porter, Erica; Moris, Dimitrios; Zhang, Xu-Feng; Arnold, Mark; Harzman, Alan; Husain, Syed; Schmidt, Carl R; Pawlik, Timothy M

2018-07-01

Given the conflicting nature of reported risk factors for post-discharge venous thromboembolism (VTE) and unclear guidelines for post-discharge pharmacoprophylaxis, we sought to determine risk factors for 30-day post-discharge VTE after colectomy to predict which patients will benefit from post-discharge pharmacoprophylaxis. Patients who underwent colectomy in the American College of Surgeons National Surgical Quality Improvement Project Participant Use Files from 2011 to 2015 were identified. Logistic regression modeling was used. Receiver-operating characteristic curves were used and the best cut-points were determined using Youden's J index (sensitivity + specificity - 1). Hosmer-Lemeshow goodness-of-fit test was used to test model calibration. A random sample of 30% of the cohort was used as a validation set. Among 77,823 cases, the overall incidence of VTE after colectomy was 1.9%, with 0.7% of VTE events occurring in the post-discharge setting. Factors associated with post-discharge VTE risk including body mass index, preoperative albumin, operation time, hospital length of stay, race, smoking status, inflammatory bowel disease, return to the operating room and postoperative ileus were included in logistic regression equation model. The model demonstrated good calibration (goodness of fit P = 0.7137) and good discrimination (area under the curve (AUC) = 0.68; validation set, AUC = 0.70). A score of ≥-5.00 had the maxim sensitivity and specificity, resulting in 36.63% of patients being treated with prophylaxis for an overall VTE risk of 0.67%. Approximately one-third of post-colectomy VTE events occurred after discharge. Patients with predicted post-discharge VTE risk of ≥-5.00 should be recommended for extended post-discharge VTE prophylaxis.

Discharge ratings for control gates at Mississippi River lock and dam 12, Bellevue, Iowa

USGS Publications Warehouse

Heinitz, Albert J.

1986-01-01

The water level of the navigation pools on the Mississippi River are maintained by the operation of tainter and roller gates at the locks and dams. Discharge ratings for the gates on Lock and Dam 12, at Bellevue, Iowa, were developed from current-meter discharge measurements made in the forebays of the gate structures. Methodology is given to accurately compute the gate openings of the tainter gates. Discharge coefficients, in equations that express discharge as a function of tailwater head , forebay head, and height of gate opening, were determined for conditions of submerged-orifice and fee-weir flow. A comparison of the rating discharges to the hydraulic-model rating discharges is given for submerged orifice flow for the tainter and roller gates.

Tubal ligation - discharge

MedlinePlus

... discharge; Tube tying - discharge; Tying the tubes - discharge; Contraception - tubal ... chap 23. Jensen JT, Mishell DR. Family planning: contraception, sterilization, and pregnancy termination. In: Lentz GM, Lobo ...

Hysterectomy - vaginal - discharge

MedlinePlus

Vaginal hysterectomy - discharge; Laparoscopically assisted vaginal hysterectomy - discharge; LAVH - discharge ... you were in the hospital, you had a vaginal hysterectomy. Your surgeon made a cut in your ...

Numerical modeling of flow focusing: Quantitative characterization of the flow regimes

NASA Astrophysics Data System (ADS)

Mamet, V.; Namy, P.; Dedulle, J.-M.

2017-09-01

Among droplet generation technologies, the flow focusing technique is a major process due to its control, stability, and reproducibility. In this process, one fluid (the continuous phase) interacts with another one (the dispersed phase) to create small droplets. Experimental assays in the literature on gas-liquid flow focusing have shown that different jet regimes can be obtained depending on the operating conditions. However, the underlying physical phenomena remain unclear, especially mechanical interactions between the fluids and the oscillation phenomenon of the liquid. In this paper, based on published studies, a numerical diphasic model has been developed to take into consideration the mechanical interaction between phases, using the Cahn-Hilliard method to monitor the interface. Depending on the liquid/gas inputs and the geometrical parameters, various regimes can be obtained, from a steady state regime to an unsteady one with liquid oscillation. In the dispersed phase, the model enables us to compute the evolution of fluid flow, both in space (size of the recirculation zone) and in time (period of oscillation). The transition between unsteady and stationary regimes is assessed in relation to liquid and gas dimensionless numbers, showing the existence of critical thresholds. This model successfully highlights, qualitatively and quantitatively, the influence of the geometry of the nozzle, in particular, its inner diameter.

Estimation of Uncertainties in Stage-Discharge Curve for an Experimental Himalayan Watershed

NASA Astrophysics Data System (ADS)

Kumar, V.; Sen, S.

2016-12-01

Various water resource projects developed on rivers originating from the Himalayan region, the "Water Tower of Asia", plays an important role on downstream development. Flow measurements at the desired river site are very critical for river engineers and hydrologists for water resources planning and management, flood forecasting, reservoir operation and flood inundation studies. However, an accurate discharge assessment of these mountainous rivers is costly, tedious and frequently dangerous to operators during flood events. Currently, in India, discharge estimation is linked to stage-discharge relationship known as rating curve. This relationship would be affected by a high degree of uncertainty. Estimating the uncertainty of rating curve remains a relevant challenge because it is not easy to parameterize. Main source of rating curve uncertainty are errors because of incorrect discharge measurement, variation in hydraulic conditions and depth measurement. In this study our objective is to obtain best parameters of rating curve that fit the limited record of observations and to estimate uncertainties at different depth obtained from rating curve. The rating curve parameters of standard power law are estimated for three different streams of Aglar watershed located in lesser Himalayas by maximum-likelihood estimator. Quantification of uncertainties in the developed rating curves is obtained from the estimate of variances and covariances of the rating curve parameters. Results showed that the uncertainties varied with catchment behavior with error varies between 0.006-1.831 m3/s. Discharge uncertainty in the Aglar watershed streams significantly depend on the extent of extrapolation outside the range of observed water levels. Extrapolation analysis confirmed that more than 15% for maximum discharges and 5% for minimum discharges are not strongly recommended for these mountainous gauging sites.

Tribological study of an aerodynamic thrust bearing in the supersonic regime

NASA Astrophysics Data System (ADS)

Dupuy, F.; Bou-Saïd, B.; Garcia, M.

2017-02-01

Nowadays, aerodynamic air thrust bearing are mainly used over a large panel of turbo-machineries. These systems become increasingly faster and up to operate in supersonic regime. They have not reached a sufficient level of research in terms of high speed. The possibility of an aerodynamic thrust bearing operating in a supersonic regime is studied. First, the air film dynamic study for high Reynolds number is based on the “modified Reynolds” equations, which take into account the inertia terms, the viscosity’s variation in the film thickness, and the turbulence. It’s an extension of the traditional model used in lubrication called the generalized Reynolds equation. The results show that a depression occur at the location of the change of slope of the tapper flat geometry. The hypothesis of presence of shock or rarefaction waves shows that the pressure gradient in the film thickness may be no longer negligible. The modified Reynolds equation may be not enough to describe the problem. A new system is built to study these phenomena: the Navier-Stokes equation are adapted to the film’s geometry. The dynamic air film’s behavior study in supersonic regime requires a shock capturing scheme called WENO scheme (“Weighted Essentially Non Oscillatory”), mainly used in shock and turbulence studies. The numerical results give the film behavior modelling of a fixed air thrust bearing pad. The evolution of the quantities shows that shock wave can occur in a thin film.

Discharge Characterization of 40 cm-Microwave ECR Ion Source and Neutralizer

NASA Technical Reports Server (NTRS)

Foster, John E.; Patterson, Michael J.; Britton, Melissa

2003-01-01

Discharge characteristics of a 40 cm, 2.45 GHz Electron Cyclotron Resonance (ECR) ion thruster discharge chamber and neutralizer were acquired. Thruster bulk discharge plasma characteristics were assessed using a single Langmuir probe. Total extractable ion current was measured as a function of input microwave power and flow rate. Additionally, radial ion current density profiles at the thruster.s exit plane were characterized using five equally spaced Faraday probes. Distinct low and high density operating modes were observed as discharge input power was varied from 0 to 200 W. In the high mode, extractable ion currents as high as 0.82 A were measured. Neutralizer emission current was characterized as a function of flow rate and microwave power. Neutralizer extraction currents as high as 0.6 A were measured.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge

NASA Astrophysics Data System (ADS)

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge.

PubMed

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.